germanium and germanium-oxide

This article is devoted to a review of studies on the determination of trace elements in germanium and germanium dioxide. For this purpose, methods both with and without preliminary matrix separation procedure have been developed and applied. The advantage of methods without a matrix separation procedure is simple and fast sample preparation, since it does not require specific devices or installations. On the other hand, the limits of detection (LODs) of trace elements remain relatively high, and the germanium matrix effect occurs when attempts are made to lower them. Since germanium and germanium dioxide are currently among the purest substances, the purest germanium containing trace elements at the level of pg g

Topics: Germanium; Limit of Detection; Spectrophotometry, Atomic; Trace Elements

One-dimensional ternary germanate nanomaterials exhibited wide application potential in the fields of magnetic devices, photocatalysis, sensors and lithium ion batteries owing to their good magnetic, photocatalytic, electrochemical and optical properties. The article reviewed the recent progress and patents on one-dimensional ternary germanate nanomaterials. The recent progress and patents on the synthesis of ternary germanate nanowires, nanorods and nanobelts synthesized by thermal evaporation, hydrothermal method and chemical vapor deposition process were demonstrated. The experimental progress and patents on the application of one-dimensional ternary germanate nanomaterials as magnetic devices, electrochemical sensors, photocatalysis and lithium ion batteries were discussed in detail. Finally, the future development direction of one-dimensional ternary germanate nanomaterials for the synthesis and application was also discussed.

Topics: Catalysis; Electric Power Supplies; Electrochemical Techniques; Germanium; Magnetics; Metals; Nanostructures; Nanotubes; Nanowires; Patents as Topic

Ge nanowires exhibit wide application potential in the fields of nanoscale devices due to their excellently optical and electrical properties. This article reviews the recent progress and patents of Ge nanowires. The recent progress and patents for the synthesis of Ge nanowires using chemical vapor deposition, laser ablation, thermal evaporation, template method and supercritical fluid-liquid-solid method are demonstrated. Amorphous germanium oxide layer and defects existing in Ge nanowires result in poor Ohmic contact between Ge nanowires and electrodes. Therefore, Ge nanowires should be passivated in order to deposit connecting electrodes before applied in nanoelectronic devices. The experimental progress and patents on the application of Ge nanowires as field effect transistors, lithium batteries, photoresistors, memory cell and fluid sensors are discussed. Finally, the future development of Ge nanowires for the synthesis and practical application is also discussed.

Topics: Electric Power Supplies; Electronics; Gases; Germanium; Nanowires; Patents as Topic

Mitochondrial DNA (mtDNA) mutations/deletions are considered to be associated with the development of age-related hearing loss (AHL). We assessed the role of accumulation of mtDNA mutations in the development of AHL using Polg(D257A) knock-in mouse, which exhibited increased spontaneous mtDNA mutation rates during aging and showed accelerated aging primarily due to increased apoptosis. They exhibited moderate hearing loss and degeneration of the hair cells, spiral ganglion cells and stria vascularis by 9 month of age, while wild-type animals did not. We next examined if mitochondrial damage induced by systemic application of germanium dioxide caused progressive hearing loss and cochlear damage. Guinea pigs and mice given germanium dioxide exhibited degeneration of the muscles and kidney and developed hearing loss due to degeneration of cochlear tissues, including the stria vascularis. Calorie restriction, which causes a metabolic shift toward increased energy metabolism in some organs, has been shown to attenuate AHL and age-related cochlear degeneration and to lower quantity of mtDNA deletions in the cochlea of mammals. Together these findings indicate that decreased energy metabolism due to accumulation of mtDNA mutations/deletions and decline of respiratory chain function play an important role in the manifestation of AHL.

Topics: Animals; Caloric Restriction; Cochlea; DNA, Mitochondrial; Energy Metabolism; Germanium; Guinea Pigs; Humans; Mice; Mitochondria; Mutation; Oligonucleotide Array Sequence Analysis; Presbycusis

Germanium-containing dietary supplements became popular in the 1970s in Japan and later in other countries, as elixirs for certain diseases (e.g., cancer and AIDS). Germanium is not an essential element. Its acute toxicity is low. However, at least 31 reported human cases linked prolonged intake of germanium products with renal failure and even death. Signs of kidney dysfunction, kidney tubular degeneration, and germanium accumulation were observed. Other adverse effects were anemia, muscle weakness, and peripheral neuropathy. Recovery of renal function is slow and incomplete even long after germanium intake was stopped. The total dose of ingested germanium (as dioxide, carboxyethyl germanium sesquioxide, germanium-lactate-citrate, or unspecified forms) varied from 15 to over 300 g; the exposure duration varied from 2 to 36 months. In laboratory animals, elevated germanium in tissues and impaired kidney and liver function were observed in a life-time drinking water (5 ppm germanium) study. Other toxicities associated with ingested germanium products in human cases were also demonstrated in animal studies with germanium dioxide and sometimes other germanium compounds. Based on the evidence of persistent renal toxicity associated with germanium dioxide, the lack of conclusive findings of differential nephrotoxicity of organic germanium compounds, and the possibility of contamination of the organic germanium products with inorganic germanium, it is clear that germanium products present a potential human health hazard.

Topics: Administration, Oral; Adolescent; Adult; Anemia; Animals; Antimutagenic Agents; Antineoplastic Agents; Child; Child, Preschool; Female; Food, Fortified; Germanium; Humans; Kidney; Lethal Dose 50; Liver; Male; Middle Aged; Muscle Weakness; Neurons; Organometallic Compounds; Propionates; Renal Insufficiency; Risk Assessment

There is no known biological requirement for germanium (Ge), germanates, or any organogermanium compound. Ge deficiency has not been demonstrated in any animal. The estimated average dietary intake of Ge in humans is 1.5 mg/d. Ge is widely distributed in edible foods, all of which, with few exceptions, contain less than 5 ppm Ge, since higher levels are toxic to most plants. Ingestion of Ge compounds has been shown to produce toxic effects in experimental animals. In recent years inorganic germanium salts and novel organogermanium compounds, such as carboxyethyl germanium sesquioxide (Ge-132) and lactate-citrate-germanate (Ge lactate citrate) have been sold as "nutritional supplements" in some countries for their purported immunomodulatory effects or as health-producing elixirs, resulting in intakes of Ge significantly exceeding the estimated average dietary intake. Since 1982, there have been 18 reported cases of acute renal dysfunction or failure, including two deaths, linked to oral intake of Ge elixirs containing germanium dioxide (GeO2) or Ge-132. In these cases, biopsies show vacuolar degeneration in renal tubular epithelial cells, without proteinuria or hematuria, in the absence of glomerular changes. Serum creatinine levels have been well above 400 mumol/L in such patients. In 17 of 18 cases, accumulated elemental Ge intakes reportedly ranged between 16 to 328 g over a 4-36 mo period, or between 100 to 2000 times the average estimated dietary intake for human. In surviving patients, renal function improved after discontinuation of Ge supplementation. However, in no case was recovery complete. One organogermanium compound, an azaspiran organogermanium compound, 2-aza-8-germanspiro[4,5] decane-2-propamine-8,8-diethyl-N,N-dimethyl dichloride (spirogermanium), has been found to cause both neurotoxicity and pulmonary toxicity in phase I and II studies examining its chemotherapeutic potential as an antitumor drug in the treatment of various malignancies. In cancer patients given the drug spirogermanium, 40% experienced marked, yet transient neurotoxicity. Two patients suffered from pulmonary toxicity. Results of phases I and II human cancer trials for spirogermanium have not been favorable, with the exception of moderate benefits for three types of malignancies. It is recommended that patients exposed to long-term (greater than 3 mo) Ge supplementation at levels well above the estimated daily intake be medically supervised and monitored for potential re

Topics: Animals; Creatinine; Germanium; Humans; Kidney; Kidney Function Tests; Kidney Tubules; Lethal Dose 50; Mice; Nervous System; Organometallic Compounds

We report two cases of renal failure following long-term ingestion of germanium dioxide (GeO2) and comment on eight other cases reported in Japan. Ge-induced nephropathy is characterized by insidious onset of renal failure without proteinuria or hematuria after oral intake of Ge-containing compounds for more than several months, and by degeneration of renal tubular cells with minor glomerular abnormality in histology. When patients ceased to ingest Ge compounds, renal function gradually recovered but never returned to the normal range. Serious extrarenal complication can contribute to an unfavorable prognosis.

Topics: Acute Kidney Injury; Adult; Cardiomegaly; Female; Germanium; Humans; Kidney; Male; Middle Aged; Myocardium; Time Factors; Tissue Distribution

Germanium and germanium-based compounds are widely used in microelectronics, optics, solar cells, and sensors. Recently, germanium and its oxides, nitrides, and phosphides have been studied as active electrode materials in lithium- and sodium-ion battery anodes. Herein, the newly introduced highly soluble germanium oxide (HSGO) was used as a versatile precursor for germanium-based functional materials. In the first stage, a germanium-dioxide-reduced graphene oxide (rGO) composite was obtained by complete precipitation of GeO

Topics: Electrodes; Germanium; Ions; Lithium

Persistent luminescence nanoparticles (PLNPs) emitting in the NIR window (700-1700 nm) have shown great promise in the field of fluorescence imaging due to their unique properties, including the absence of in situ excitation and low optical scattering in tissues. However, they are still facing some challenges, such as irregular shape, wide size distribution and poor persistent luminescence performance. Here, we report a facile mesoporous template method for synthesizing mSiO

Topics: Calcium Compounds; Chromium; Germanium; Infrared Rays; Luminescence; Nanoparticles; Optical Imaging; Oxides; Particle Size; Silicon Dioxide; Surface Properties; Ytterbium; Zinc Oxide

The occurrence of anthocyanin (ACN) and metal (Me) complexes has been widely supported by many research works while the possibility that ACNs bind to metalloids (Mds) is yet to be proven. Here, metalloids (H

Topics: Anthocyanins; Boric Acids; Coordination Complexes; Density Functional Theory; Germanium; Metalloids; Models, Molecular; Quantum Theory; Spectrophotometry, Ultraviolet

A novel process is developed for the recovery of germanium from the leach liquor of Zener diodes using solvent extraction. Extraction is carried out using a phosphonium ionic liquid, Cyphos IL 104, as an extractant. Preliminary investigations carried out on Ge(IV) extraction using Cyphos IL 104 include influence of various parameters like temperature, equilibration time, and concentration of extractant, chloride ion, and acid on the distribution of Ge(IV). NMR spectrum of Ge(IV)-extractant complex was analyzed to support the proposed extracting species of germanium. Quantitative extraction of germanium is achieved from 7 mol/L HCl onwards using 0.1 mol/L Cyphos IL 104. Optimum conditions for quantitative extraction of Ge from leach liquor of Zener diodes were developed. McCabe-Thiele plots were constructed for the extraction and stripping of Ge(IV) from leach liquor to determine the number of stages required at a particular aqueous/organic phase ratio. Separation of germanium from copper, mercury and iron has been achieved by selective stripping of these metal ions. Germanium is recovered as germanium oxide from the strip solution using NaOH as a precipitating agent. The synthesized germanium oxide is characterized by XRD, FE-SEM and EDX techniques.

Topics: Chlorides; Germanium; Ionic Liquids; Metals

The development of photoactive nanomaterials with high biocompatibility for targeted tumor phototherapy is of great significance for antitumor applications; this study presents a novel phototherapeutic agent, the Ge/GeO2 complex, which shows broad photoabsorption in the near infrared (NIR) region. As a result, it can synchronously produce reactive oxygen species (ROS) and heat under NIR irradiation. After being loaded onto macrophages, Ge/GeO2 could be delivered to tumors in a targeted fashion. Combining the abovementioned merits together, macrophage-loaded Ge/GeO2 realized in vivo synergetic photothermal and photodynamic outcomes to completely remove solid tumors in mice via intravenous administration. In this study, B-ultrasonography was also employed to monitor the tumor evolution after phototherapy, revealing a sequential process of tumor necrosis, liquefaction/softening, and finally disappearance. In addition, Ge/GeO2 proposed in this study shows negligible cytotoxicity and hematotoxicity, especially after being loaded onto macrophages.

Topics: Animals; Cell Survival; Coordination Complexes; Female; Germanium; Hep G2 Cells; Humans; Infrared Rays; Macrophages; Mice; Mice, Nude; Neoplasms; Photochemotherapy; Phototherapy; Reactive Oxygen Species

Topics: Animals; Ascorbate Oxidase; Ascorbic Acid; Enzyme Assays; Fluorescent Dyes; Germanium; Limit of Detection; Male; Manganese; Metal Nanoparticles; Rats; Smartphone; Spectrometry, Fluorescence; Zinc

To investigate the effects of β-carboxyethyl germanium sequioxide (Ge-132) and germanium dioxide (GeO

Topics: Catalase; Germanium; Germination; Malondialdehyde; Oenothera biennis; Organometallic Compounds; Peroxidase; Plant Roots; Plant Shoots; Propionates; Seeds; Sodium Chloride; Stress, Physiological; Superoxide Dismutase

We present a novel four-layer structure consisting of bottom, second, third, and surface layers in the sensing region, for a D-shaped step-index fiber-optic evanescent wave (FOEW) sensor. To reduce the background noise, the surface of the longitudinal section in the D-shaped region is coated with a light-absorbing film. We check the morphologies of the second and surface layers, examine the refractive indices (RIs) of the third and surface layers, and analyze the composition of the surface layer. We also investigate the effects of the thicknesses and RIs of the third and surface layers and the LA film on the light transmission and sensitivity of the FOEW sensors. The results highlight the very good sensitivity of the proposed FOEW sensor with a four-layer structure, which reached -0.077 (μg/l)

Topics: Animals; Antibodies, Anti-Idiotypic; Balsams; Biosensing Techniques; Drug Combinations; Equipment Design; Fiber Optic Technology; Germanium; Goats; Gutta-Percha; Immunoglobulin G; Mice; Optical Fibers; Polymers; Zinc Oxide

In this paper, we present the results of a study on the effects of exogenous antioxidant germanium (Ge) on seed germination and seedling growth, and its role as a radical scavenger that regulates related enzymes, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), under salt stress. Seeds were incubated in 0, 50, 100, 150, 200, 250 and 300 mM NaCl to determine the salt tolerance of the Lycium ruthenicum Murr seedlings and from the results, the critical and ultimate salt concentrations were chosen for the next experiment. Subsequently, two treatments (seeds soaked in Ge and Ge added to salt) with four concentrations of GeO2 (0, 5, 10 and 20 μM) were used with the critical (150 mM) and ultimate salt concentrations (250 mM). The results demonstrated that salt alone inhibited seed germination significantly (≥150 mM) and reduced seedling growth (≥200 mM). The addition of exogenous Ge to the salt solution, as well as soaking the seeds in Ge, attenuated the salt stress effects in a manner dependent on the dose of Ge, as indicated by the increased percentage of seeds that germinated and improved seedling growth. The addition of Ge also showed a significant reversal of salt stress on the activities of antioxidant enzymes, with a decrease in SOD and POD activity, but an increase in CAT activity with 150 mM NaCl, and enhancement of SOD, POD and CAT with 250 mM NaCl. Correspondingly, the level of malondialdehyde was decreased significantly by each Ge treatment under salt stress. Further, for L. ruthenicum, adding 10 Ge and seeds soaked in 5 Ge were the most effective treatments. To our knowledge, this is the first report to show the protective effects of exogenous Ge against salt-induced oxidative damage in L. ruthenicum seed germination and seedling growth. Thus, L. ruthenicum can be used in areas with salty soil and Ge can promote the plants' salt tolerance.

Topics: Antioxidants; Catalase; Germanium; Germination; Lycium; Malondialdehyde; Peroxidase; Plant Roots; Plant Shoots; Salt Tolerance; Seedlings; Seeds; Sodium Chloride; Stress, Physiological; Superoxide Dismutase

To elucidate the mechanism(s) responsible for the profound impact germanium has on the setting reaction of zinc silicate glass ionomer cements (GICs).. Five <45μm glass powder compositions (0.48-xSiO2, xGeO2, 0.36 ZnO, 0.16 CaO; where x=0.12, 0.24, 0.36, 0.48mol. fraction) were synthesized. Glass degradation was assessed under simulated setting conditions using acetic acid from 0.5 to 60min, monitoring the concentrations of ions released using ICP-OES. Subsequently, GICs were prepared by mixing fresh glass powders with polyacrylic acid (PAA, Mw=12,500g/mol, 50wt% aq. solution) at a 1:0.75 ratio. Cement structure and properties were evaluated using ATR-FTIR and rheology (for 60min), as well as 24h biaxial flexural strength.. Reduced Si:Ge ratios yielded faster degrading glasses, yet contrary to expectation, the corresponding ATR-FTIR spectra indicated slower crosslinking within the GIC matrix. Rheology testing found the initial viscosity cement pastes reduced with decreased Si:Ge, and Ge containing cements all set significantly slower than the Si based GIC. Interestingly, biaxial flexural strength remained consistent regardless of setting behavior.. This counter-intuitive combination of behaviors is attributed to the presence of a chemical complex species specific to Ge-containing glasses that delays, but does not hinder, the formation of the GIC matrix. These findings embody chemical complex species as a mechanism to decouple glass reactivity from cement setting rate, a mechanism with the potential to enhance the utility of GICs in both dental and orthopaedic applications.

Topics: Calorimetry; Compressive Strength; Dental Restoration Failure; Germanium; Glass Ionomer Cements; Materials Testing; Powders; Silicates; Spectrophotometry, Atomic; Spectroscopy, Fourier Transform Infrared; Viscosity; X-Ray Diffraction; Zinc Compounds

The ITO (indium tin oxide) conductive glass-matrix CuS-GeO2-TiO2 composite coating was generated via EPD (electrophoretic deposition) and followed by a sintering treatment at 450°C for 40 minutes. Characterizations of the CuS-GeO2-TiO2 composite coating were taken by SEM (scanning electron microscope), XRD (X-ray diffraction), EDX (energy dispersive X-ray), UV-Vis DRS (ultraviolet-visible diffuse reflection spectrum), and FT-IR (Fourier transform infrared spectroscopy). Results showed that CuS and GeO2 had dispersed in this CuS-GeO2-TiO2 composite coating (mass percentages for CuS and GeO2 were 1.23% and 2.79%, respectively). The electrochemical studies (cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization) of this CuS-GeO2-TiO2 composite coating electrode were performed in pH = 9.51 Na2CO3-NaHCO3 buffer solution containing 0.50 mol/L CH3OH under the conditions of visible light, ultraviolet light (λ = 365 nm), and dark (without light irradiation as control), respectively. Electrochemical studies indicated that this CuS-GeO2-TiO2 composite coating electrode had better photoelectrocatalytic activity than the pure TiO2 electrode in the electrocatalysis of methanol under visible light.

Topics: Catalysis; Copper; Electrochemical Techniques; Electrodes; Germanium; Methanol; Photochemical Processes; Sulfides; Tin Compounds; Titanium

Effect of the structural changes, electrical conductivity, and dielectric properties on the addition of a third glass-former, GeO2, to the borophosphate glasses, 40Li2O-10B2O3-(50 - x)P2O5-xGeO2, x = 0-25 mol %, has been studied. Introduction of GeO2 causes the structural modifications in the glass network, which results in a continuous increase in electrical conductivity. Glasses with low GeO2 content, up to 10 mol %, show a rapid increase in dc conductivity as a result of the interlinkage of slightly depolymerized phosphate chains and negatively charged [GeO4](-) units, which enhances the migration of Li(+) ions. The Li(+) ions compensate these delocalized charges connecting both phosphate and germanium units, which results in reduction of both bond effectiveness and binding energy of Li(+) ions and therefore enables their hop to the next charge-compensating site. For higher GeO2 content, the dc conductivity increases slightly, tending to approach a maximum in Li(+) ion mobility caused by the incorporation of GeO2 units into phosphate network combined with conversion of GeO4 to GeO6 units. The strong cross-linkage of germanium and phosphate units creates heteroatomic P-O-Ge bonds responsible for more effectively trapped Li(+) ions. A close correspondence between dielectric and conductivity parameters at high frequencies indicates that the increase in conductivity indeed is controlled by the modification of structure as a function of GeO2 addition.

Topics: Boron Compounds; Electric Conductivity; Germanium; Glass; Ions; Lithium; Magnetic Resonance Spectroscopy; Phosphates; Spectrum Analysis, Raman; Temperature; Transition Temperature

In this paper, we present a high-sensitivity polymer fiber-optic evanescent wave (FOEW) sensor with a three-layer structure that includes bottom, inter-, and surface layers in the sensing region. The bottom layer and inter-layer are POFs composed of standard cladding and the core of the plastic optical fiber, and the surface layer is made of dilute Canada balsam in xylene doped with GeO2. We examine the morphology of the doped GeO2, the refractive index and composition of the surface layer and the surface luminous properties of the sensing region. We investigate the effects of the content and morphology of the GeO2 particles on the sensitivity of the FOEW sensors by using glucose solutions. In addition, we examine the response of sensors incubated with staphylococcal protein A plus mouse IgG isotype to goat anti-mouse IgG solutions. Results indicate very good sensitivity of the three-layer FOEW sensor, which showed a 3.91-fold improvement in the detection of the target antibody relative to a conventional sensor with a core-cladding structure, and the novel sensor showed a lower limit of detection of 0.2ng/l and a response time around 320s. The application of this high-sensitivity FOEW sensor can be extended to biodefense, disease diagnosis, biomedical and biochemical analysis.

Topics: Animals; Biosensing Techniques; Equipment Design; Fiber Optic Technology; Germanium; Glucose; Goats; Immunoglobulin G; Mice; Optical Fibers; Refractometry; Staphylococcaceae; Staphylococcal Protein A; Xylenes

Non-classical ionomer glasses like those based on zinc-boron-germanium glasses are of special interest in a variety of medical applications owning to their unique combination of properties and potential therapeutic efficacy. These features may be of particular benefit with respect to the utilization of glass ionomer cements for minimally invasive dental applications such as the atruamatic restorative treatment, but also for expanded clinical applications in orthopedics and oral-maxillofacial surgery. A unique system of zinc-boron-germanium-based glasses (10 compositions in total) has been designed using a Design of Mixtures methodology. In the first instance, ionomer glasses were examined via differential thermal analysis, X-ray diffraction, and (11)B MAS NMR spectroscopy to establish fundamental composition - structure-property relationships for the unique system. Secondly, cements were synthesized based on each glass and handling characteristics (working time, Wt, and setting time, St) and compression strength were quantified to facilitate the development of both experimental and mathematical composition-structure-property relationships for the new ionomer cements. The novel glass ionomer cements were found to provide Wt, St, and compression strength in the range of 48-132 s, 206-602 s, and 16-36 MPa, respectively, depending on the ZnO/GeO2 mol fraction of the glass phase. A lower ZnO mol fraction in the glass phase provides higher glass transition temperature, higher N4 rate, and in combination with careful modulation of GeO2 mol fraction in the glass phase provides a unique approach to extending the Wt and St of glass ionomer cement without compromising (in fact enhancing) compression strength. The data presented in this work provide valuable information for the formulation of alternative glass ionomer cements for applications within and beyond the dental clinic, especially where conventional approaches to modulating working time and strength exhibit co-dependencies (i.e. the enhancement of one property comes at the expense of the other) and therefore limit development strategies.

Topics: Biomechanical Phenomena; Boron; Compressive Strength; Germanium; Glass Ionomer Cements; Humans; Magnetic Resonance Spectroscopy; Materials Testing; Regression Analysis; Thermodynamics; X-Ray Diffraction; Zinc

A green-light emitting germanium nanocrystal-based biosensor to monitor lysosomal pH changes is developed. The Ge nanocrystals are synthesized in an aqueous solution with a significantly enhanced photoluminescence quantum yield of 26%. This synthesis involves a facile solution based route which avoided the use of toxic or environmentally unfriendly agents. Importantly, the photoluminescence intensity of the synthesized Ge nanocrystals is particularly sensitive to changes in pH between 5 and 6. When incubated with cultured cells, the nanocrystals are internalized and subsequently translocated via the lysosomal pathway, and the Ge nanocrystals' fluorescence are greatly enhanced, even when the lysosomal pH is only slightly increased. These results reveal that the Ge nanocrystals possess high pH sensitivity compared to a commercially available dye, LysoSensor Green DND-189. The fluorescent properties of the Ge nanocrystals are demonstrated to be dependent on both the crystal form and their surface chemistry. The superior fluorescence properties and bioapplicability of the Ge nanocrystals makes them a promising intracellular bioimaging probe for monitoring various pH-sensitive processes in cells.

Topics: Benzimidazoles; Biosensing Techniques; Cell Line, Tumor; Cell Survival; Fluorescent Dyes; Germanium; Humans; Hydrogen-Ion Concentration; Luminescence; Lysosomes; Microscopy, Confocal; Microscopy, Electron, Transmission; Nanoparticles; Naphthalimides; Oxygen; Photochemistry; Photoelectron Spectroscopy; Quantum Dots; Spectroscopy, Fourier Transform Infrared; Temperature; Ultraviolet Rays

The recombination luminescence from Zn imperfections has been extensively investigated; however, there have been few reports on the long persistent luminescence of Zn imperfections as emitting centers. Here, we observed a long persistent luminescence in blue-white visible region from 6 ZnO:3 GeO2:Al2O3 phosphor with Zn imperfections as emitting centers. Persistent luminescence could be observed beyond 2h with naked eyes. The properties of traps were also elaborated by the measurements of thermo-luminescence spectra and photo-stimulated luminescence decay curves. Furthermore, a long persistent phosphor with warm white color was developed by doping Cr(3+) into 6 ZnO:3 GeO2:Al2O3 phosphor.

Topics: Aluminum Hydroxide; Aluminum Oxide; Germanium; Luminescence; Luminescent Agents; Zinc; Zinc Oxide

Er(3+) doped and Er(3+)/Ce(3+) co-doped silica-germanate glasses were synthesized by high-temperature melt-quenching technique. A detailed study of the 1.53μm spectroscopic properties and thermal stability was presented in this work. The absorption spectra, 1.53μm emission spectra and fluorescence lifetimes were measured and investigated, along with the quantitative calculations and analyses of Judd-Ofelt intensity parameters, stimulated absorption and emission cross-sections and the product of FWHM×σem(p). It was found that the prepared samples have outstanding thermal stability (Tg=585°C), large FWHM (77nm and 108nm) and high stimulated emission cross-sections (9.55×10(-28)cm(3) and 8.72×10(-28)cm(3)) of Er(3+). The 1.53μm fluorescence intensity improved significantly with the introduction of Ce(3+). Furthermore, the wavelength dependent gain coefficient G(λ) of (4)I13/2→(4)I15/2 transition of Er(3+) was determined by means of the absorption and emission cross-sections. The results indicate that the developed glass co-doped with Er(3+)/Ce(3+) is a promising gain medium applied for broadband amplifier pumped with a 980nm laser diode.

Topics: Cations; Cerium; Erbium; Germanium; Glass; Hot Temperature; Lasers, Semiconductor; Silicon Dioxide; Spectrometry, Fluorescence; Spectrophotometry

We apply first principles quantum mechanical techniques to the study of the solid solution Si1-xGexO2 of α-quartz where silicon atoms are progressively substituted with germanium atoms, to different extents, as a function of the substitutional fraction x. For the first time, the whole range of the substitution (x = 0.0, 0.1[Formula: see text], 0.[Formula: see text], 0.5, 0.[Formula: see text], 0.8[Formula: see text], 1.0), including pure end-members α-SiO2 and α-GeO2, is explored. An elongated supercell (doubled along the c crystallographic axis) is built with respect to the unit cell of pure α-quartz and a set of 13 symmetry-independent configurations is considered. Their structural, energetic, dielectric, elastic and piezoelectric properties are computed and analyzed. All the calculations are performed using the CRYSTAL14 program with a Gaussian-type function basis set with pseudopotentials, and the hybrid functional PBE0; all geometries are fully optimized at this level of theory. In particular, for each configuration, fourth-rank elastic and compliance tensors and third-rank direct and converse piezoelectric tensors are computed. It has already been shown that the structural distortion of the solid solution increases, almost linearly, as the substitutional fraction x increases. The piezoelectric properties of the Si1-xGexO2 solid solution are found to increase with x, with a similar quasi-linear behavior. The electromechanical coupling coefficients are enhanced as well and the linear trend recently predicted by Ranieri et al (2011 Inorg. Chem. 50 4632) can be confirmed from first principles calculations. These doped crystals do represent good candidates for technological applications requiring high piezoelectric coupling and high thermal stability.

Topics: Computer Simulation; Elastic Modulus; Electric Impedance; Germanium; Micro-Electrical-Mechanical Systems; Models, Chemical; Models, Molecular; Molecular Conformation; Quartz; Silicon Dioxide; Stress, Mechanical

In the work the new glass compositions in the GeO2-GaO-BaO system have been prepared and thermal, structural properties of in germanate glasses co-doped with Yb(3+)/Tb(3+)ions were studied. Glasses were obtained by conventional high-temperature melt-quenching technique. The study of the crystallization kinetics processes of glasses co-doped with 0.7Yb2O3:0.7Tb2O3 was performed with DSC measurements. The activation energies have been calculated using Freedman analysis and verified with the Flynn-Wall-Ozawa method. In this order, the DSC curves have been registered with different heating rates, between 5 and 15 degrees/min. The structure of fabricated glasses has been studied by infrared and Raman spectroscopes. The effect of heat treatment on the structural properties was determined. In all glass samples the dominated infrared absorbance band at 800cm(-1) corresponds to asymmetric stretching motions of GeO4 tetrahedra containing bridging (Ge-O(Ge)) and non-bridging (Ge-O(-)) oxygens. Additionally, the influence of heat treatment on the luminescent properties was evaluated. Strong luminescence at 489, 543, 586 and 621nm corresponding to (5)D4→(7)FJ (J=6, 5, 4, 3) transitions was measured. The highest upconversion emission intensity was obtained in the germanate glass co-doped with 0.7Yb2O3/0.7Tb2O3.

Topics: Cations; Crystallization; Germanium; Glass; Kinetics; Luminescence; Spectrum Analysis, Raman; Terbium; Thermodynamics; Ytterbium

Esterification reaction between different fatty acid namely; lauric, stearic, oleic and linoleic acids and polyethylene glycol-400 were performed. The produced polyethylene glycol ester were reacted with p-amine benzoic acid followed by condensation reaction with germanium dioxide in presence of sodium carbonate to form desired germinate surfactants. The chemical structures of the synthesized surfactants were determined using different spectra tools. The surface parameter including: the critical micelle concentration (CMC), effectiveness (π(cmc)), efficiency (Pc20), maximum surface excess (Γ(max)) and minimum surface area (A(min)), were calculated from the surface tension measurements. The synthesized surfactants showed higher surface activity. The thermodynamic parameters showed that adsorption and micellization processes are spontaneous. It is clear that the synthesized nonionic surfactants showed their tendency towards adsorption at the interfaces and also micellization in the bulk of their solutions. The synthesized surfactants were tested against different strain of bacteria using inhibition zone diameters. The synthesized surfactants showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative as well as fungi. The promising inhibition efficiency of these compounds against the sulfate reducing bacteria facilitates them to be applicable as new categories of sulfate reducing bacteria biocides.

Topics: 4-Aminobenzoic Acid; Adsorption; Carbonates; Drug Resistance, Bacterial; Esterification; Esters; Fatty Acids; Germanium; Gram-Negative Bacteria; Gram-Positive Bacteria; Polyethylene Glycols; Surface Properties; Surface-Active Agents; Thermodynamics

We demonstrate the use of silk based proteins to control the particle/crystallite size during GeO2 formation, using a bio-mimetic approach at circumneutral pH and ambient temperature. Multicrystalline GeO2 was prepared from germanium tetraethoxide (TEOG) in the presence of different silk-based proteins: Bombyx mori silk (native silk) and two chimeric proteins prepared by linking a germania binding peptide (Ge28: HATGTHGLSLSH) with Bombyx mori silk via chemical coupling at different peptide loadings (silk-Ge28 10% and silk-Ge28 50%). The mineralisation activity of the silk-based proteins was compared with that of peptide Ge28 as a control system. GeO2 mineralisation was investigated in water and in citric acid/bis-tris propane buffer at pH 6. Morphology, particle size, crystallinity, water and organic content of the materials obtained were analysed to study the effect of added biomolecules and mineralisation environment on material properties. In the presence of silk additives well-defined cube-shape hybrid materials composed of hexagonal germania and up to ca. 5 wt% organic content were obtained. The cubic particles ranged from 0.4 to 1.4 μm in size and were composed of crystalline domains in the range 35-106 nm depending on the additive used and synthesis conditions. The organic material incorporated in the mineral did not appear to affect the unit cell dimensions. The silk and chimeric proteins in water promote material formation and crystal growth, possibly via an effective ion-channelling mechanism, however further studies are needed to assert to what extent the presence of the silk impacts on nucleation and growth stages. The germania binding peptide alone did not have any significant effect on reaction rate, yield or the material's properties compared to the blank. Interestingly, the peptide content in the silk chimeras tested did not affect mineralisation. The presence of buffer inhibited mineral condensation rate and yield. The use of silk-based biomolecules allows control of crystallite/particle size of hybrid materials opening up opportunities for bio-inspired approaches to be applied for the synthesis of functional germania based devices and materials.

Topics: Animals; Biomimetics; Bombyx; Germanium; Microscopy, Electron, Scanning; Oligopeptides; Particle Size; Silk; Spectroscopy, Fourier Transform Infrared; Thermogravimetry; X-Ray Diffraction

An investigation has been made of glass beads and optical fibres as novel dosimeters for small-field photon radiation therapy dosimetry. Commercially available glass beads of largest dimension 1.5 mm and GeO2-doped SiO2 optical fibres of 5 mm length and 120 µm diameter were characterized as thermoluminescence dosimeters. Results were compared against Monte-Carlo simulations with BEAMnrc/DOSXYZnrc, EBT3 Gafchromic film, and a high-resolution 2D-array of liquid-filled ionization chambers. Measurements included relative output factors and dose profiles for square-field sizes of 1, 2, 3, 4, and 10 cm. A customized Solid-Water® phantom was employed, and the beads and fibres were placed at defined positions along the longitudinal axis to allow accurate beam profile measurement. Output factors and the beam profile parameters were compared against those calculated by BEAMnrc/DOSXYZnrc. The output factors and field width measurements were found to be in agreement with reference measurements to within better than 3.5% for all field sizes down to 2 cm2 for both dosimetric systems, with the beads showing a discrepancy of no more than 2.8% for all field sizes. The results confirm the potential of the beads and fibres as thermoluminescent dosimeters for use in small photon radiation field sizes.

Topics: Fiber Optic Technology; Germanium; Glass; Humans; Monte Carlo Method; Phantoms, Imaging; Photons; Silicon Dioxide; Thermoluminescent Dosimetry; Water

Many applications of germanium (Ge) are underpinned by effective oxide removal and surface passivation. This important surface treatment step often requires H-X (X = Cl, Br, I) or HF etchants. Here, we show that aqueous citric acid solutions are effective in the removal of GeOx. The stability of citric acid-treated Ge(100) is compared to HF and HCl treated surfaces and analyzed by X-ray photoelectron spectroscopy. Further Ge surface passivation was investigated by thiolation using alkane monothiols and dithiols. The organic passivation layers show good stability with no oxide regrowth observed after 3 days of ambient exposure.

Topics: Citric Acid; Germanium

A new open-framework germanate, denoted as GeO-JU90, was prepared by the hydrothermal synthesis method using 1,5-bis(methylpyrrolidinium)pentane dihydroxide as the organic structure-directing agent (SDA). The structure of GeO-JU90 was determined from synchrotron X-ray powder diffraction (XRPD) data using the charge-flipping algorithm. It revealed a complicated framework structure containing 11 Ge atoms in the asymmetric unit. The framework is built of 7-connected Ge7 clusters and additional tetrahedral GeO3(OH) units forming a new three-dimensional interrupted framework with interesting 12 × 12 × 11-ring intersecting channels. The Ge K-edge extended X-ray absorption fine structure (EXAFS) analysis was performed to provide the local structural information around Ge atoms, giving rise to a first-shell contribution from about 4.2(2) O atoms at the average distance of 1.750(8) Å. The guest species in the channels were subsequently determined by the simulated annealing method from XRPD data combining with other characterization techniques, e.g., (13)C NMR spectroscopy, infrared spectroscopy (FTIR), compositional analyses, and thermogravimetric analysis (TGA). Crystallographic data |(C15N2H32)(NH4)|[Ge11O21.5(OH)4], orthorhombic Ama2 (No. 40), a = 37.82959 Å, b = 15.24373 Å, c = 12.83659 Å, and Z = 8.

Topics: Algorithms; Germanium; Models, Molecular; Organometallic Compounds; Powder Diffraction

Topics: Aged, 80 and over; Female; Foreign Bodies; Germanium; Humans; Ileum; Intestinal Mucosa; Intestinal Perforation; Serous Membrane

In this work, a new and non-conventional oxide glass composition based on Bi2O3-GeO2-ZnO system has been formulated with an aim to realize low phonon oxide glass and elucidate its performance when co-doped with Ho(3+)/Yb(3+) for the energy transfer based NIR emission at 2 μm from Ho(3+) ions under Yb(3+) excitation. The glass with 1.0 mol% Ho2O3 and 0.5 mol% Yb2O3 has exhibited maximum energy transfer rate (3602 s(-1)) and energy transfer efficiency (65.92%). Important radiative properties have been predicted for emission transitions of Ho(3+) ions using intensity parameters derived from measured absorption spectra using standard Judd-Ofelt theory. At lower acceptor ion concentration (0.1 mol%), an efficient NIR to visible up-conversion emission has been observed based on two photon absorption process which has found to be reduced significantly at higher Ho(3+) concentrations with simultaneous enhancement in 2 μm emission. Hence, this newly developed glass codoped with Yb(3+)/Ho(3+) is promising glass for sensitized 2 μm emission applications as broad band tunable lasers because of the combination of low phonon energy (707 cm(-1)), high energy transfer efficiency, moderately high emission cross-section (5.33×10(-21) cm(2)) and larger effective half-width of the emission band value of 169 nm.

Topics: Bismuth; Germanium; Glass; Holmium; Luminescence; Ytterbium; Zinc Oxide

Germanium- and tellurium-based glasses have been largely studied due to their recognized potential for photonics. In this paper, we review our recent studies that include the investigation of the Stokes and anti-Stokes photoluminescence (PL) in different glass systems containing metallic and semiconductor nanoparticles (NPs). In the case of the samples with metallic NPs, the enhanced PL was attributed to the increased local field on the rare-earth ions located in the proximity of the NPs and/or the energy transfer from the metallic NPs to the rare-earth ions. For the glasses containing silicon NPs, the PL enhancement was mainly due to the energy transfer from the NPs to the Er(3+) ions. The nonlinear (NL) optical properties of PbO-GeO2 films containing gold NPs were also investigated. The experiments in the pico- and subpicosecond regimes revealed enhanced values of the NL refractive indices and large NL absorption coefficients in comparison with the films without gold NPs. The reported experiments demonstrate that germanate and tellurite glasses, having appropriate rare-earth ions doping and NPs concentration, are strong candidates for PL-based devices, all-optical switches, and optical limiting.

Topics: Germanium; Materials Testing; Metal Nanoparticles; Refractometry; Semiconductors; Tellurium

Magnesiothermic reduction can directly convert SiO2 into Si nanostructures. Despite intense efforts, efficient fabrication of highly nanoporous silicon by Mg still remains a significant challenge due to the exothermic reaction nature. By employing table salt (NaCl) as a heat scavenger for the magnesiothermic reduction, we demonstrate an effective route to convert diatom (SiO2) and SiO2/GeO2 into nanoporous Si and Si/Ge composite, respectively. Fusion of NaCl during the reaction consumes a large amount of heat that otherwise collapses the nano-porosity of products and agglomerates silicon domains into large crystals. Our methodology is potentially competitive for a practical production of nanoporous Si-based materials.

Topics: Chemistry Techniques, Synthetic; Germanium; Hot Temperature; Nanostructures; Porosity; Silicon; Silicon Dioxide

The structure of several network-forming liquids and glasses is considered, where a focus is placed on the detailed information that is made available by using the method of neutron diffraction with isotope substitution (NDIS). In the case of binary network glass-forming materials with the MX2 stoichiometry (e.g. GeO2, GeSe2, ZnCl2), two different length scales at distances greater than the nearest-neighbour distance manifest themselves by peaks in the measured diffraction patterns. The network properties are influenced by a competition between the ordering on these "intermediate" and "extended" length scales, which can be manipulated by changing the chemical identity of the atomic constituents or by varying state parameters such as the temperature and pressure. The extended-range ordering, which describes the decay of the pair-correlation functions at large-r, can be represented by making a pole analysis of the Ornstein-Zernike equations, an approach that can also be used to describe the large-r behaviour of the pair-correlation functions for liquid and amorphous metals where packing constraints are important. The first applications are then described of the NDIS method to measure the detailed structure of aerodynamically-levitated laser-heated droplets of "fragile" glass-forming liquid oxides (CaAl2O4 and CaSiO3) at high-temperatures (~2000 K) and the structure of a "strong" network-forming glass (GeO2) under pressures ranging from ambient to ~8 GPa. The high-temperature experiments show structural changes on multiple length scales when the oxides are vitrified. The high-pressure experiment offers insight into the density-driven mechanisms of network collapse in GeO2 glass, and parallels are drawn with the high-pressure behaviour of silica glass. Finally, the hydrogen-bonded network of water is considered, where the first application of the method of oxygen NDIS is used to measure the structures of light versus heavy water and a difference of approximately equal to 0.5% is found between the O-D and O-H intra-molecular bond lengths. The experimental data are best matched by using path integral molecular dynamics simulations with a flexible anharmonic water model, and the results support a competing quantum effects model for water in which its structural and dynamical properties are governed by an offset between intra-molecular and inter-molecular quantum contributions.

Topics: Aluminum Compounds; Calcium Compounds; Germanium; Glass; Hot Temperature; Models, Molecular; Neutron Diffraction; Pressure; Silicates

We study the cytotoxicity of indium chloride (InCl₃) in Chinese hamster lung fibroblasts, the V79 cells, using MTT assay. The results showed that InCl₃ did not induce significant cytotoxicity at various concentrations tested. In addition, the frequency of micronuclei (MN) was assayed to evaluate the genotoxic effects of InCl₃ in V79 cells. InCl₃ at concentrations ranged 0.1-1 μM significantly increased MN frequency in a concentration-dependent manner. Both catalase and superoxide dismutase at concentrations of 75 and 150 μg/mL significantly inhibited InCl₃-induced MN. Similarly, Germanium oxide (GeO₂) and dimercaprol expressed antigenotoxic effects. From these findings, it is concluded that InCl₃ is a potent genotoxic chemical, which may be mediated partly by inducing oxidative stress. The significance of this study shows that the workers in the semiconductor factories should be cautious in exposing to the hazardous genotoxic InCl₃.

Topics: Animals; Catalase; Cell Line; Cell Survival; Cricetinae; Cricetulus; Dimercaprol; DNA Damage; Fibroblasts; Free Radical Scavengers; Germanium; Indium; Lung; Micronucleus Tests; Oxidative Stress; Reactive Oxygen Species; Superoxide Dismutase

Single-crystalline metal germanate nanowires, including SrGe4O9, BaGe4O9, and Zn2GeO4 were successfully grown on carbon textile via a simple low-cost hydrothermal method on a large scale. The as-grown germanate nanowires-carbon textiles were directly used as binder-free anodes for lithium-ion batteries, which exhibited highly reversible capacity in the range of 900-1000 mA h g(-1) at 400 mA g(-1), good cyclability (no obvious capacity decay even after 100 cycles), and excellent rate capability with a capacity of as high as 300 mA h g(-1) even at 5 A g(-1). Such excellent electrochemical performance can be ascribed to the three-dimensional interconnected conductive channels composed of the flexible carbon microfibers, which not only serve as the current collector but also buffer the volume change of the active material upon cycling. Additionally, the one-dimensional nanostructures grown directly on the carbon microfibers also ensure fast charge carrier (e(-) and Li(+)) transport, large surface areas, better permeabilities, and more active sites, which also contributed to the improved electrochemical performance.

Topics: Carbon; Electric Power Supplies; Electrochemical Techniques; Germanium; Ions; Lithium; Nanowires; Oxides

A GeO(2)-SiO(2)-chitosan-medium (GSCM)-coated hollow optical fiber (HOF) is proposed. The HOF consists of three parts: the fiber core (air), cladding (SiO(2)), and coating (GSCM), which shows the highest refractive index of the three. The HOF's luminescence properties and surface morphology are investigated. Their adsorption capacity for Rhodopseudomonas palustris CQK 01 is also assayed. We discovered that when the amount of 2GeO(2)-SiO(2) sol dopant is 0.9 mass percent, the HOF exhibits the highest luminous intensity and uniform light distribution, and the adsorption capacity for the cell is 3.2 times higher than that of a normal solid optical fiber.

Topics: Biofilms; Cells, Immobilized; Chitosan; Germanium; Glass; Optical Fibers; Silicon Dioxide

We compute the temperature-dependent barrier for α-relaxations in several liquids, without adjustable parameters, using experimentally determined elastic, structural, and calorimetric data. We employ the random first order transition (RFOT) theory, in which relaxation occurs via activated reconfigurations between distinct, aperiodic minima of the free energy. Two different approximations for the mismatch penalty between the distinct aperiodic states are compared, one due to Xia and Wolynes (Proc. Natl. Acad. Sci. U. S. A. 2000, 97, 2990), which scales universally with temperature as for hard spheres, and one due to Rabochiy and Lubchenko (J. Chem. Phys. 2013, 138, 12A534), which employs measured elastic and structural data for individual substances. The agreement between the predictions and experiment is satisfactory, given the uncertainty in the measured experimental inputs. The explicitly computed barriers are used to calculate the glass transition temperature for each substance--a kinetic quantity--from the static input data alone. The temperature dependence of both the elastic and structural constants enters the temperature dependence of the barrier over an extended range to a degree that varies from substance to substance. The lowering of the configurational entropy, however, seems to be the dominant contributor to the barrier increase near the laboratory glass transition, consistent with previous experimental tests of the RFOT theory using the XW approximation. In addition, we compute the temperature dependence of the dynamical correlation length, also without using adjustable parameters. These agree well with experimental estimates obtained using the Berthier et al. (Science 2005, 310, 1797) procedure. Finally, we find the temperature dependence of the complexity of a rearranging region is consistent with the picture based on the RFOT theory but is in conflict with the assumptions of the Adam-Gibbs and "shoving" scenarios for the viscous slowing down in supercooled liquids.

Topics: Boron Compounds; Chlorides; Elasticity; Germanium; Glycerol; Kinetics; Microscopy; Organophosphorus Compounds; Silicon Dioxide; Thermodynamics; Toluene; Toluidines; Zinc Compounds

This work reports on the spectral dependence of both nonlinear refraction and absorption in lead-germanium oxide glasses (PbO-GeO₂) containing silver nanoparticles. We have found that this material is suitable for all-optical switching at telecom wavelengths but at the visible range it behaves either as a saturable absorber or as an optical limiter.

Topics: Germanium; Glass; Lead; Light; Materials Testing; Nanoparticles; Nonlinear Dynamics; Oxides; Refractometry; Scattering, Radiation; Silver; Surface Plasmon Resonance

Improving optical property is critical for optimizing the power conversion efficiency of organic solar cells. In the present research, we show that modification of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) layer with GeO2 leads to 15% improvement of power conversion efficiency in a polymer solar cells through enhancement of short circuit currents. Modified PEDOT:PSS layer with optimized concentration of GeO2 assists active layer absorbing much light by playing a role of optical spacer. Using AFM and grazing incidence X-ray diffraction (GIXD) data, we also present the evidence that an addition of GeO2 does not affect crystallinity of active layer.

Topics: Electric Power Supplies; Electron Transport; Equipment Design; Equipment Failure Analysis; Germanium; Nanostructures; Solar Energy

The 2.7 μm emission properties in Er3+-doped bismuthate (Bi2O3-GeO2-Ga2O3-Na2O) glass were investigated in the present Letter. An intense 2.7 μm emission in Er3+-doped bismuthate glass was observed. It is found that Er3+-doped bismuthate glass possesses high spontaneous transition probability A (65.26 s(-1)) and large 2.7 μm emission cross section σ(em) (9.53×10(-21) cm2) corresponding to the stimulated emission of Er3+:4I11/2→4I13/2 transition. The emission characteristic and energy transfer process upon excitation of a conventional 980 nm laser diode in bismuthate glass were analyzed. Additionally, the structure of bismuthate glass was analyzed by the Raman spectrum. The advantageous spectroscopic characteristics of Er3+ single-doped bismuthate glass together with the prominent thermal property indicate that bismuthate glass might become an attractive host for developing solid-state lasers around 2.7 μm.

Topics: Absorption; Bismuth; Erbium; Gallium; Germanium; Glass; Oxides; Sodium Compounds; Spectrophotometry, Infrared; Spectrum Analysis, Raman

Heavy metal oxide glasses, containing bismuth and/or lead in their glass structure are new alternatives for rare eart (RE) doped hosts. Hence, the study of the structure of these vitreous systems is of great interest for science and technology. In this research work, GeO(2)-PbO-Bi(2)O(3) glass host doped with Er(3+)/Yb(3+) ions was synthesized by a conventional melt quenching method. The Fourier transform infrared (FTIR) results showed that PbO and Bi(2)O(3) participate with PbO(4) tetragonal pyramids and strongly distort BiO(6) octahedral units in the glass network, which subsequently act as modifiers in glass structure. These results also confirmed the existence of both four and six coordination of germanium oxide in glass matrix.

Topics: Bismuth; Erbium; Germanium; Glass; Lead; Oxides; Spectroscopy, Fourier Transform Infrared; Ytterbium

We report on the directed synthesis of germanium oxide (GeO(x)) nanowires (NWs) by locally catalyzed thermal oxidation of aligned arrays of gold catalyst-tipped germanium NWs. During oxygen anneals conducted above the Au-Ge binary eutectic temperature (T > 361 °C), one-dimensional oxidation of as-grown Ge NWs occurs by diffusion of Ge through the Au-Ge catalyst droplet, in the presence of an oxygen containing ambient. Elongated GeO(x) wires grow from the liquid catalyst tip, consuming the adjoining Ge NWs as they grow. The oxide NWs' diameter is dictated by the catalyst diameter and their alignment generally parallels that of the growth direction of the initial Ge NWs. Growth rate comparisons reveal a substantial oxidation rate enhancement in the presence of the Au catalyst. Statistical analysis of GeO(x) nanowire growth by ex situ transmission electron microscopy and scanning electron microscopy suggests a transition from an initial, diameter-dependent kinetic regime, to diameter-independent wire growth. This behavior suggests the existence of an incubation time for GeO(x) NW nucleation at the start of vapor-liquid-solid oxidation.

Topics: Crystallization; Gases; Germanium; Macromolecular Substances; Materials Testing; Molecular Conformation; Nanostructures; Oxidation-Reduction; Particle Size; Phase Transition; Solutions; Surface Properties

A GeO2 doped triangular-core photonic-crystal fiber (PCF) is designed and fabricated to allow the generation of a hollow beam through a nonlinear-optical transformation by femtosecond pulses at 1040 nm from a high power Yb-doped PCF laser oscillator. The hollow beam supercontinuum is obtained at far field by adjusting incident light polarization to excite the high order supermode, behaving as a mode convertor. The supercontinuum ranging from 540 to 1540 nm is achieved with an average power of 1.04 W.

Topics: Computer-Aided Design; Equipment Design; Equipment Failure Analysis; Fiber Optic Technology; Germanium; Lasers; Porosity; Refractometry

Near-infrared and mid-infrared (MIR) ultrabroad emission bands were observed in as-grown and annealed Bi(2)O(3)-GeO(2) binary glasses, in the wavelength ranges of 1000-1800 nm and 1800-3020 nm, respectively. The MIR emission band could appear through high doping ratio of Bi(2)O(3) or annealing process in air atmosphere. The structure of these glasses, the transformation of emission centers, and the effect of Al ions doping have been discussed, with the conclusion that the Bi(2)O(3)-GeO(2) binary glasses could be a promising laser material.

Topics: Atmosphere; Bismuth; Germanium; Glass; Infrared Rays; Luminescent Measurements

We report generation of femtosecond optical pulses tunable in the 1.6-2.5 μm range using GeO2-doped core silica-cladding fibers. Optical solitons with a duration of 80-160 fs have been measured by the FROG technique in the 2-2.3 μm range. To the best of our knowledge, these are the longest wavelength temporally characterized solitons generated in silica-based fibers. We have also demonstrated more than octave-spanning femtosecond supercontinuum generation in the 1.0-2.6 μm range.

Topics: Fiber Optic Technology; Germanium; Lasers; Optical Fibers; Silicon Dioxide

High oxygen content apatite germanates, La(10)Ge(6-x)W(x)O(27+x), have been prepared by doping on the Ge site with W. In addition to increasing the oxygen content, this doping strategy is shown to result in stabilisation of the hexagonal lattice, and yield high conductivities. Structural studies of La(10)Ge(5.5)W(0.5)O(27.5) show that the interstitial oxygen sites are associated to a different degree with the Ge/WO(4) tetrahedra, leading to five coordinate Ge/W and significant disorder for the oxygen sites associated with these units. Raman spectroscopy studies suggest that in the case of the WO(5) units, the interstitial oxygen is more tightly bonded and therefore not as mobile as in the case of the GeO(5) units, thus not contributing significantly to the conduction process.

Topics: Apatites; Electric Conductivity; Germanium; Lanthanum; Models, Molecular; Oxides; Spectrum Analysis, Raman; Tungsten; X-Ray Diffraction

Size-tunable GeO₂ nanocubes were initially prepared by a modified sono-assisted reverse micelle method and then functionalized with an amino-terminated silanizing agent. Subsequently, gold decorated GeO₂ nanocomposites were prepared at pH ≈ 7 and 80 °C. It was found that well-dispersed gold nanoparticles on GeO₂ nanocubes could be obtained only if gold salt is abundant to favor simultaneous, homogeneous nucleation of gold particles. Additional gold ions were reduced onto these attached 'seed' particles accompanied by synchronous dissolution of water-soluble GeO₂ cores, resulting in gold hollow cubic shells. The GeO₂ nanocubes and Au/GeO₂ nanocomposites as well as gold hollow cubic shells were characterized by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and UV-visible spectroscopy. In particular, gold hollow cubic shells feature a plasmon resonance peak at above 900 nm, which renders it quite promising in biochemical applications.

Topics: Germanium; Gold; Gold Compounds; Isocyanates; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nanocomposites; Nanoshells; Particle Size; Silanes; Solubility; Spectrometry, X-Ray Emission; Spectrophotometry; Surface Plasmon Resonance; Water; X-Ray Diffraction

We have calculated the vibrational frequencies of clusters of atoms from the first principles by using the density-functional theory in the local density approximation (LDA). We are also able to calculate the electronic binding energy for all of the clusters of atoms from the optimized structure. We have made clusters of BanOm (n, m=1-6) and have determined the bond lengths, vibrational frequencies as well as intensities in each case. We find that the peroxide cluster BaO2 occurs with the O-O vibrational frequency of 836.3 cm(-1). We also find that a glass network occurs in the material which explains the vibrational frequency of 67 cm(-1). The calculated values agree with those measured from the Raman spectra of barium peroxide and Ba-B-oxide glass. We have calculated the vibrational frequencies of BaO4, GeO4 and SiO4 each in tetrahedral configuration and find that the vibrational frequencies in these systems depend on the inverse square root of the atomic mass.

Topics: Barium Compounds; Germanium; Mathematical Computing; Oxides; Silicon Compounds; Silicon Dioxide; Spectrum Analysis, Raman; Vibration

A novel all-fiber laser based on a highly GeO2-doped dispersion-shifted Tm-codoped fiber, pumped at 1.56 µm wavelength and lasing at 1.862 µm wavelength with a slope efficiency up to 37% was demonstrated. The single-mode Tm-doped fiber with the 55GeO2-45SiO2 core was fabricated for the first time by MCVD technique. The laser produces spectral side bands, resulting from the four-wave mixing owing to the shift of the zero-dispersion-wavelength of the fiber to the laser wavelength, thus, making it potentially particularly attractive for dispersion management and ultrashort pulse generation.

Topics: Equipment Design; Equipment Failure Analysis; Fiber Optic Technology; Germanium; Lasers, Solid-State; Thulium

This paper reports on the spectroscopic properties and energy transfer analysis of Tm(3+)-doped BaF(2)-Ga(2)O(3)-GeO(2)-La(2)O(3) glasses with different Tm(2)O(3) doping concentrations (0.2, 0.5, 2.0, 2.5, 3.0, 3.5, 3.5, 4.0 wt%). Mid-IR fluorescence intensities in the range of 1,300 nm-2,200 nm have been measured when excited under an 808 nm LD for all the samples with the same pump power. Energy level structure and Judd-Ofelt parameters have been calculated based on the absorption spectra of Tm(3+), cross-relaxation rates and multi-phonon relaxation rates have been estimated with different Tm(2)O(3) doping concentrations. The maximum fluorescence intensity at around 1.8 mum has been obtained in Tm(2)O(3)-3 wt% sample and the maximum value of calculated stimulated emission cross-section of Tm(3+) in this sample is about 0.48 x 10(-20) cm(2) at 1,793 nm, and there is not any crystallization peak in the DSC curve of this sample, which indicate the potential utility of Tm(3+)-doped BaF(2)-Ga(2)O(3)-GeO(2)- La(2)O(3) glass for 2.0-microm optical fiber laser.

Topics: Crystallization; Energy Transfer; Fluorescence; Germanium; Glass; Lasers; Spectrum Analysis

To solve the problem of low growth rate and metabolism level in suspension cultures of protocorm-like bodies (PLBs) of Dendrobium huoshanense. The effects of germanium on PLB proliferation and accumulation of polysaccharides together with nutrient utilization were investigated and the contents of reducing sugars, soluble proteins, the activities of antioxidant enzymes and redox status of the cells of PLB were analyzed. The results indicated that the optimum concentration of germanium dioxide (4.0 mg/L) significantly enhanced the cell growth and accumulation of polysaccharides, greatly improved contents of reducing sugars and soluble proteins, increased the activities of superoxide dismutase (SOD) and catalase (CAT) but decreased the activity of peroxidase(POD). The cell dry weight and production of polysaccharides were 32.6 g/L and 3.78 g/L, respectively. The analysis of cellular redox status showed that the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) in cells and the activity of glutathione reductase were significantly increased by the addition of germanium dioxide. The suitable concentration of germanium dioxide was beneficial to the cell growth and the accumulation of polysaccharides.

Topics: Cell Proliferation; Culture Techniques; Dendrobium; Germanium; Oxidation-Reduction; Polysaccharides; Superoxide Dismutase

Adding a small amount of commercial GeO(2) into aqueous suspension significantly enhanced the photocatalytic activity of titania-based photocatalysts for the degradation of dyes.

Topics: Catalysis; Germanium; Photolysis; Suspensions; Titanium

The Eu(3+) ion was introduced into Er(3+) doped Bi(2)O(3)-GeO(2)-Ga(2)O(3)-Na(2)O (BGGN) glasses to improve the 1.5 microm band emission. As a function of Eu(2)O(3) doped content, we observed the increase in non-radiative decay rate of Er(3+) not only (4)I(11/2) energy level but also (4)I(13/2) energy level, while the lifetime of Er(3+):(4)I(11/2) and (4)I(13/2) levels were shortened from 607 to 241 micros and from 3.37 to 1.88 ms, respectively. Accordingly, the upconversion fluorescence (green and red) was quenched. The total quantum efficiency of the Er(3+):(4)I(13/2) increased with the Eu(2)O(3) content increasing up to 0.2 mol% due to the state-selective energy transfer from Er(3+) to Eu(3+).

Topics: Absorption; Bismuth; Energy Transfer; Erbium; Europium; Fluorescence; Gallium; Germanium; Glass; Oxides; Sodium Compounds

The semiconductor element, germanium (Ge), is essential for the manufacture of modern integrated circuits. Because of its anti-tumor and immunomodulative effects, Ge-containing compounds are also used as health-promoting ingredients in food. However, some histological studies have shown the toxic effects of Ge-containing compounds on various organs, including the central nervous system. Even now, the effect of germanium on auditory system function is not completely clear. To clarify this question, brainstem auditory evoked potentials (BAEPs) were applied to examine the effect of germanium dioxide (GeO(2)) on the ascending auditory pathway. Since the voltage-gated sodium channel is important to neuron activation and nerve conduction, the effect of GeO(2) on voltage-gated sodium channels was also examined. The result revealed GeO(2) elevated the BAEPs threshold dose-dependently. GeO(2) also prolonged latencies and interpeak latencies (IPLs) of BAEPs, but the amplitudes of suprathreshold intensities (90dB) did not show any obvious change. In addition, the results of whole cell patch clamp studies indicated GeO(2) reduced inward sodium current. These results suggest the toxic effect of GeO(2) on the conduction of the auditory system, and that inhibitory effect of GeO(2) on the voltage-gated sodium channels might play a role in GeO(2)-induced abnormal hearing loss.

Topics: Animals; Auditory Pathways; Body Weight; Cell Line, Tumor; Dose-Response Relationship, Drug; Electrophysiology; Evoked Potentials, Auditory, Brain Stem; Germanium; Ion Channel Gating; Male; Mice; Neurons; Patch-Clamp Techniques; Rats; Rats, Wistar; Sodium Channel Blockers; Sodium Channels

The aim of this work is to compare the radiosensitizing effect between organic and inorganic germanium compounds and to investigate whether nanometer-sized germanium particles can act as radiosensitizers.. Bis (2-carboxyethylgermanium) sesquioxide (Ge-132), germanium oxide (GeO(2)) and germanium nanoparticles were used in this study. Cell viability was determined by clonogenic survival assay. Cellular DNA damage was evaluated by alkaline comet assay, confocal microscopy and the cellular level of phospho-histone H2AX (gamma-H2AX).. Nanometer-sized germanium particles were fabricated. They have a similar radiosensitizing effect as that of GeO(2). Conversely, Ge-132 did not enhance the radiosensitivity of cells. Comet assay was employed to evaluate the level of DNA damage and confirmed that inorganic germanium compounds enhanced cellular radiosensitivity. Notably, the comet assay indicated that the nanoparticle itself caused a higher level of DNA damage. The possibility that germanium nanoparticles per se caused DNA damage was ruled out when the cellular level of gamma-H2AX was examined.. We demonstrated that inorganic but not organic germanium compounds exerted radiosensitizing effect in cells. Nanometer-sized germanium particles were fabricated and were able to enhance the radiosensitivity of cells. Confounding effect may occur when comet assay is used to estimate the level of DNA damage in the presence of germanium nanoparticles.

Topics: Animals; Cell Survival; CHO Cells; Cricetinae; Cricetulus; DNA Damage; Germanium; Histones; Nanoparticles; Organometallic Compounds; Phosphorylation; Propionates; Radiation Tolerance; Radiation-Sensitizing Agents

New classes of amphiphilic polyesters were prepared from metallated (Si, Ge) fatty methyl ester (FAME) precursors and poly(tetramethylene oxide) glycol. Hydrosilylation of 10-undecenoic methyl ester by tetramethyldisiloxane occurred at 80 degrees C in the presence of Karstedt's catalyst, and hydrogermylation of the same FAME derivative was obtained at the same temperature under radical AIBN initiation. These diester precursors, obtained in high yields (approximately 90%), reacted with poly(tetramethylene oxide) glycol under free solvent to give silicon polymers or germanium oligomers. These condensed materials display both the characteristic of organic-inorganic hybrid materials and those of amphiphilic polymers. The nature of organometallic fragment (hydrophobicity of tetramethyldisiloxy and sterical hindrance of diphenylgermyl) was shown to influence the chemical reactivity of the polymerizable monomers and the physical properties of the resulting copolymers. The amphiphilicity of these materials provides a driving force for the formation of small objects (approximately 1 nm), making them very attractive as hybrid nanocontainers.

Topics: Fatty Acids, Unsaturated; Germanium; Glycols; Magnetic Resonance Spectroscopy; Polyesters; Polymers; Siloxanes; Surface-Active Agents

Recently, tellurium (Te), antimony (Sb) and germanium (Ge) have been used as an alloy in phase-change optical magnetic disks, such as digital versatile disk-random access memory (DVD-RAM) and DVD-recordable disk (DVD-RW). Although these metalloids, the so-called "exotic" elements, are known to be non-essential and harmful, little is known about their toxic effects and metabolism. Metalloid compounds, tellurite, antimonite and germanium dioxide, were simultaneously administered to rats. Their distributions metabolites were determined and identified by speciation. Te and Sb accumulated in red blood cells (RBCs): Te accumulated in RBCs in the dimethylated form, while Sb accumulated in the inorganic/non-methylated form. In addition, trimethyltelluronium (TMTe) was the urinary metabolite of Te, whereas Sb in urine was not methylated but oxidized. Ge was also not methylated in rats. These results suggest that each metalloid is metabolized via a unique pathway.

Topics: Animals; Antimony; Drug Combinations; Environmental Pollutants; Erythrocytes; Germanium; Mass Spectrometry; Rats; Rats, Wistar; Tellurium

We describe an approach for acquiring high quality x-ray absorption fine structure (XAFS) spectroscopy spectra with wide energy range at high pressure using diamond anvil cell (DAC). Overcoming the serious interference of diamond Bragg peaks is essential for combining XAFS and DAC techniques in high pressure research, yet an effective method to obtain accurate XAFS spectrum free from DAC induced glitches has been lacking. It was found that these glitches, whose energy positions are very sensitive to the relative orientation between DAC and incident x-ray beam, can be effectively eliminated using an iterative algorithm based on repeated measurements over a small angular range of DAC orientation, e.g., within +/-3 degrees relative to the x-ray beam direction. Demonstration XAFS spectra are reported for rutile-type GeO2 recorded by traditional ambient pressure and high pressure DAC methods, showing similar quality at 440 eV above the absorption edge. Accurate XAFS spectra of GeO2 glass were obtained at high pressure up to 53 GPa, providing important insight into the structural polymorphism of GeO2 glass at high pressure. This method is expected be applicable for in situ XAFS measurements using a diamond anvil cell up to ultrahigh pressures.

Topics: Absorption; Algorithms; Diamond; Germanium; Glass; Pressure; Reproducibility of Results; Spectrum Analysis; X-Rays

Photo-patternable GeO(2)-contained organic-inorganic hybrid films, which can be used for the low cost and mass production of integrated photonic circuits, were synthesized by combining a low-temperature sol-gel process with a spin-coating technique. Optical waveguide properties and photochemical activities of the hybrid sol-gel films were characterized and monitored by a prism coupling technique and a Fourier transform infrared spectroscopy. Advantages for fabrication of ridge structures based on the hybrid films were demonstrated by one-step spin-coating process followed by direct ultraviolet light irradiation. The results indicate that the as-prepared photo-patternable hybrid materials have great applicability for the fabrication of photonic components, and the fabrication process has the advantages of cost-effect and very short processing time over inorganic materials patterning methods.

Topics: Crystallization; Gels; Germanium; Inorganic Chemicals; Light; Materials Testing; Membranes, Artificial; Optics and Photonics; Organic Chemicals; Photochemistry; Photons; Surface Properties

Biomimetic synthesis is emerging as an advantageous alternative to the harsh synthetic conditions traditionally used in metal oxide syntheses techniques. Silaffins, proteins from the C. fusiformis diatom, form silica in an aqueous environment under benign conditions. Amine terminated PAMAM and PPI dendrimers are effective mimics of silaffins and other silica precipitating polyamines. We have expanded the scope of dendrimer mediated metal oxide formation to include titanium dioxide, a photocatalyst, and germanium dioxide, a blue photoluminescent material. The nanoparticles were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (IR), and X-ray diffraction patterns (XRD). A variable temperature XRD analysis of TiO(2) nanoparticles was conducted to study the transition from anatase to rutile. TiO(2) nanoparticles synthesized in phosphate buffer showed a 200 degrees C decrease in the anatase to rutile transition temperature relative to TiO(2) templated in water. XRD analysis of GeO(2) nanoparticles in either water or phosphate buffer reveal crystalline alpha-phase germanium oxide. To our knowledge, this is the first report of the synthesis of crystalline GeO(2) under ambient conditions.

Topics: Biomimetic Materials; Buffers; Catalysis; Dendrimers; Germanium; Microscopy, Electron, Scanning; Nanoparticles; Photochemistry; Spectroscopy, Fourier Transform Infrared; Titanium; Transition Temperature; Water; X-Ray Diffraction

So-called germanium 'health' products including dietary supplements, cosmetics, accessories, and warm bath service containing germanium compounds and metalloid are popular in Japan. Subchronic and chronic oral exposure of germanium dioxide (GeO(2)), popular chemical form of inorganic germanium causes severe germanium toxicosis including death and kidney dysfunction in humans and experimental animals. Intestinal absorption of neutralized GeO(2) or germanate is almost complete in humans and animals. However, it is not known whether germanium is cutaneously absorbed. We tested dermal absorption of neutralized GeO(2) or germanate using male F344/N rats. Three groups of rats were treated with a 3-h topical application of hydrophilic ointment containing graded level of neutralized GeO(2) (pH 7.4): 0, 0.21 and 0.42 mg GeO(2)/g. Germanium concentration in blood and tissues sampled from rats after topical application of inorganic germanium was measured by inductively coupled plasma-mass spectrometry. Animals topically applied 0.42 mg GeO(2)/g ointment had significantly higher germanium concentrations in plasma, liver, and kidney than those of rats that received no topical germanium. The results indicate that skin is permeable to inorganic germanium ion or germanate and recurrent exposure of germanium compounds may pose a potential health hazard.

Topics: Administration, Cutaneous; Animals; Antimutagenic Agents; Dose-Response Relationship, Drug; Germanium; Japan; Kidney; Liver; Male; Mass Spectrometry; Ointments; Permeability; Rats; Rats, Inbred F344; Skin; Skin Absorption; Tissue Distribution

The interfacial reaction of hafnium-silicate [(HfO(2))(x)(SiO(2))(1-x), x=0.5,0.7] thin films grown on Ge(001) by atomic layer deposition was investigated using x-ray photoelectron spectroscopy and medium energy ion scattering spectroscopy. According to the peak changes in Hf 4f and Ge 3d, the Hf-silicate film reacted with the oxidized Ge surface forming Hf-germanate at the interface. The formation of Hf-germanate induced band bending of the Ge substrate at the interface and decreased band gap to 5.1 eV, which was lower than that of GeO(2) (5.6 eV). In particular, the interfacial reaction was dependent on the amount of SiO(2) in the Hf-silicate film, which resulted in more decrement in the band gap in the film with a high SiO(2) fraction.

Topics: Germanium; Hafnium; Silicates; Silicon Dioxide; Spectroscopy, Electron Energy-Loss; Temperature

Glasses with the composition of (99.5-chi)GeO2-chiWO(3)-0.5Bi2O3 (chi=3, 6, 9 mol%) and (99.5-psi)GeO2-psiBaO-0.5Bi2O3 (psi=3, 6, 9 mol%) were prepared. Their thermal, emission and absorption measurements were carried out. The near-infrared super broadband emission of the prepared samples peak around 1.3 microm was discovered. The results indicated, in GeO2-WO3-Bi2O3 glasses, increasing amount of WO3 brought about the broadening of FWHM, prolonging of lifetime and enhancing of thermal stabilities. While in GeO2-BaO-Bi2O3 glasses, concomitant with the increasing amount of BaO were the broadened FWHM as well as the prolonged lifetime. Red-shift tendency of absorption edges was discovered in both two groups of glasses indicating the Bi5+ ions might take responsibility for the broadband emission.

Topics: Barium Compounds; Bismuth; Germanium; Glass; Hot Temperature; Oxides; Spectrophotometry, Infrared; Time Factors; Tungsten

The absorption spectra and upconversion fluorescence spectra of Er3+/Yb3+-codoped natrium-gallium-germanium-bismuth glasses are measured and investigated. The intense green (533 and 549 nm) and red (672 nm) emission bands were simultaneously observed at room temperature. The quadratic dependence of the green and red emission on excitation power indicates that the two-photon absorption processes occur. The influence of Ga2C3 on upconversion intensity is investigated. The intensity of green emissions increases slowly with increasing Ga2O3 content, while the intensity of red emission increases significantly. The possible upconversion mechanisms for these glasses have also been discussed. The maximum phonon energy of the glasses determined based on the infrared (IR) spectral analysis is as low as 740 cm-1. The studies indicate that Bi2O3-GeO2-Ga2O3-Na2O glasses may be potential materials for developing upconversion optical devices.

Topics: Bismuth; Erbium; Gallium; Germanium; Glass; Oxides; Sodium Compounds; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Ytterbium

The comparison between non-magnetic spin-Peierls (SP) and magnetic Néel ground states have been investigated in CuGeO(3) doped with Zn(2+), Ni(2+) and Mn(2+) ions by using the electron spin resonance (ESR) techniques in the temperature range of 3-300 K. It was concluded that the one-dimensional (1D) antiferromagnetic (AF) spin chain formed of spin-1/2 (Cu(2+)) ions is broken by spin-0 (Zn(2+)), spin-1 (Ni(2+)), and spin-5/2 (Mn(2+)) ions, giving uncoupled spins at the end of the chains that give extra contribution to the spectra at lower temperature. An almost linearly dependence of frequency of resonance field has been showed for X-, K- and Q-band spectra. By the analysis of resonance field-frequency relations, the effects of the internal field is refined and thus the spectroscopic g-factor and internal field were calculated to be g=1.9386 and H(i)=148 G, respectively.

Topics: Copper; Electron Spin Resonance Spectroscopy; Germanium; Spin Labels; Temperature

A method for the separation of no-carrier-added (nca) arsenic radionuclides from bulk amounts of irradiated germanium oxide (GeO2) target was developed in view of their potentialities in different biological and nuclear medicine applications. The beta- emitting 77As radionuclide, produced by the decay of 77Ge through the natGe(n,gamma)77Ge nuclear reaction, was used for standardization of the radiochemical separation procedure. The radiochemical separation was performed by precipitation followed by solvent extraction. About 99% post-irradiation recovery of the GeO2 target material, in a form suitable for reuse in future irradiation, was achieved. The developed method was suitable for the production of nca arsenic radionuclides either as trivalent or pentavalent arsenic in various vehicles which provided flexibility of formulations of different kinds of compound. The overall radiochemical yield for the complete separation of 77As was 90%. The separated nca 77As was of high radionuclidic purity and did not contain detectable amounts of the target material. This method can be adopted for the radiochemical separation of other different arsenic radionuclides produced from GeO2 through cyclotron as well as reactor irradiation.

Topics: Arsenic; Beta Particles; Clinical Laboratory Techniques; Cyclotrons; Germanium; Radiochemistry; Radioisotopes

Ab initio band-structure calculations based on density functional theory have been completed for alpha-quartz phase GeO2 to obtain electric-field gradients (efg) for oxygen atoms, including those for GeO2 at elevated pressure and temperature. To interpret the resulting efg values and examine correlations between structure and 17O quadrupolar coupling parameters, additional ab initio self-consistent Hartree-Fock molecular orbital calculations were completed. The quadrupolar coupling constant was found to have a strong dependence on Ge-O distance and angleGe-O-Ge, with the quadrupolar asymmetry parameter being primarily dependent on angleGe-O-Ge. Analytical expressions describing these dependencies consistent with earlier investigations of analogous silicate compounds are also reported.

Topics: Computer Simulation; Germanium; Models, Chemical; Models, Molecular; Molecular Conformation; Oxygen Isotopes; Phase Transition; Spin Labels

One fascinating high-pressure behavior of tetrahedral glasses and melts is the local coordination change with increasing pressure, which provides a structural basis for understanding numerous anomalies in their high-pressure properties. Because the coordination change is often not retained upon decompression, studies must be conducted in situ. Previous in situ studies have revealed that the short-range order of tetrahedrally structured glasses and melts changes above a threshold pressure and gradually transforms to an octahedral form with further pressure increase. Here, we report a thermal effect associated with the coordination change at given pressures and show distinct thermal behaviors of GeO(2) glass in tetrahedral, octahedral, and their intermediate forms. An unusual thermally induced densification, as large as 16%, was observed on a GeO(2) glass at a pressure of 5.5 gigapascal (GPa), based on in situ density and x-ray diffraction measurements at simultaneously high pressures and high temperatures. The large thermal densification at high pressure was found to be associated with the 4- to 6-fold coordination increase. Experiments at other pressures show that the tetrahedral GeO(2) glass displayed small thermal densification at 3.3 GPa arising from the relaxation of intermediate range structure, whereas the octahedral glass at 12.3 GPa did not display any detectable thermal effects.

Topics: Germanium; Glass; Hot Temperature; Pressure; Scattering, Small Angle; Spectrum Analysis, Raman; X-Ray Diffraction

This investigation addressed the effect of germanium dioxide (GeO(2))-induced mitochondrial dysfunction on hearing acuity. Guinea pigs were fed chow that contained 0%, 0.15%, or 0.5% GeO(2). The animals that were fed 0.5% GeO(2) for 2 months developed hearing impairment chiefly due to degeneration of stria vascularis and cochlear supporting cells, which exhibited electron-dense mitochondrial inclusions. Cytochrome c oxidase activity was decreased in the skeletal muscles and kidney, which also exhibited electron-dense mitochondrial inclusions. No apparent pathological changes were observed in the utricle, semicircular canal, or among the vestibular nerve fibers, or in the liver or heart. The untreated animals and those treated with 0.15% GeO(2) did not exhibit hearing impairment or pathological changes in any organs. These findings suggest that administration of 0.5% GeO(2) induces mitochondrial dysfunction in the stria vascularis and supporting cells in the cochlea, as in the skeletal muscles and kidney, thereby causing hearing impairment in the guinea pigs.

Topics: Animals; Cochlea; Germanium; Guinea Pigs; Hearing Loss; Male; Mitochondria; Mitochondrial Diseases

Germanium (Ge) is commonly used in the semiconductor industry as well as health-promoting and medical field. Biologically, germanium possesses erythropoietic, anti-microbial, anti-tumor, anti-amyloidosis, and immunomodulative effects. However, toxic effects of Ge-containing compounds on kidney, muscle, neuronal cells, and nerves have been reported. Mitochondrial dysfunction was found to be involved in the pathogenesis of GeO(2)-induced nephropathy and myopathy. Since it is well known that mitochondria play a major role in apoptosis triggered by many stimuli, an effort was made to examine whether the Ge-induced neurotoxicity occurs through mitochondria-mediated apoptosis. A mouse neuroblastoma cell line, Neuro-2A, was used in the present study. After incubating with 0.1-800microM of GeO(2) for 0-72h, the cell viability of Neuro-2A cells was inhibited in a dose- and time-dependent manner. Further analysis showed that aside from the changes in the nuclear morphology responsible for apoptosis, the release of cytochrome c, the loss of mitochondrial membrane potential, the translocation of Bax, and the reduction of Bcl-2 expression were also observed in Neuro-2A cells after GeO(2) treatment. These results indicate that the mitochondria-mediated apoptosis is involved in this in vitro model of GeO(2)-induced neurotoxicity.

Topics: Acridine Orange; Analysis of Variance; Animals; Antimutagenic Agents; Apoptosis; bcl-2-Associated X Protein; Cell Line, Tumor; Cell Survival; Cytochromes c; Dose-Response Relationship, Drug; Ethidium; Flow Cytometry; Germanium; Immunohistochemistry; In Situ Nick-End Labeling; Membrane Potential, Mitochondrial; Mice; Mitochondria; Neuroblastoma; Proto-Oncogene Proteins c-bcl-2; Time Factors

During recent experimental studies, the erbium:YAG laser has been shown to be more efficient for lithotripsy and more precise for incision of soft urinary tissues than the conventional holmium:YAG laser. Mid-infrared optical fibers are being developed to allow endoscopic delivery of Er:YAG laser radiation. This paper describes the simple construction and characterization of a side-firing germanium oxide fiber for potential use with the Er:YAG laser in endourology.. The 450-microm-core side-firing fibers were constructed from germanium oxide fibers by polishing the distal tip at a 45 degrees angle and placing a protective quartz cap over the tip. The Er:YAG laser radiation, with a wavelength of 2.94 microm, was transmitted through the fibers.. The fiber transmission rate and damage threshold measured 48 +/- 4% and 149 +/- 37 mJ, respectively (n = 6 fibers). Sufficient pulse energies were transmitted through the side-firing fibers to produce contact tissue ablation.

Topics: Aluminum; Erbium; Fiber Optic Technology; Germanium; Humans; Laser Therapy; Lithotripsy, Laser; Optical Fibers; Urinary Calculi; Urologic Surgical Procedures; Yttrium

Endoscopic applications of the Erbium:YAG laser have been limited due to the lack of a suitable optical fiber delivery system. The purpose of this study was to compare the transmission of Er:YAG laser radiation through germanium oxide trunk fibers with silica and sapphire fiber tips for potential use in contact tissue ablation during endoscopy.. Er:YAG laser radiation with a wavelength of 2.94 microm, pulse length of 300 microseconds, pulse energies from 5 to 1,360 mJ, coupled into pulse repetition rates of 3-10 Hz, was through 1-m-long germanium oxide fibers with either 1-cm-long, 550-microm-diameter silica or sapphire tips.. Transmission through the germanium oxide/sapphire fibers measured 65+/-5% compared with 55+/-4% for the germanium oxide/silica fibers (P<0.05). The damage threshold for the hybrid fibers averaged 309+/- 44 mJ and 126+/-43 mJ, respectively (n = 7 fibers each) (P<0.05). The highest pulse energies transmitted through the fibers were 700 mJ and 220 mJ, respectively.. Improved index-matching of the trunk fiber and fiber tip at 2.94 microm resulted in higher transmission and damage thresholds for the germanium oxide/sapphire fibers. The germanium oxide/sapphire fiber may represent a promising mid-infrared optical fiber delivery system for use in endoscopic applications of the Er:YAG laser requiring a flexible, biocompatible, and robust fiber delivery system for contact tissue ablation.

Topics: Aluminum Oxide; Endoscopes; Equipment Design; Erbium; Fiber Optic Technology; Germanium; Laser Therapy; Optical Fibers; Silicon Dioxide

The biomineralization capacity of the photosynthetic marine diatom Nitzschia frustulum was harnessed to fabricate Si-Ge oxide nanocomposite materials. Germanium was incorporated into the diatom cell by a two-stage cultivation process. In stage 1, the N. frustulum cell suspension was grown up to cell density of 3 x 10(6) cells/mL in 0.35 mM silicic acid within a bubble-column photobioreactor. In stage 2, when all of the soluble silicon was consumed, 0.10 mM Ge(OH)4 or a mixture of 0.020 mM Ge(OH)4 and 0.25 mM Si(OH)4 were added to Si-starved cells. The cells assimilated soluble germanium by a surge uptake mechanism. The cell mass was thermally annealed in air at 800 degrees C for 6 h to oxidize carbonaceous materials. The thermally annealed cell biomass was characterized by TEM-EDS, FT-IR, and XRD. These measurements confirmed the formation nanostructured Ge-Si oxides composed of CaSiO3 and Ca3GeO5.

Topics: Calcium Compounds; Cell Culture Techniques; Crystallization; Diatoms; Germanium; Marine Biology; Molecular Conformation; Nanostructures; Silicates

Germanium oxide (GeO2) nanowires have been prepared by heating a mixture of Ge powder and carbon in an Ar + O2 mixture at 900 degrees C. The nanowires have been characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and spectroscopic measurements. The nanowires are single crystalline with diameters in the 15-250-nm range. They exhibit characteristic blue luminescence.

Topics: Crystallization; Electric Wiring; Germanium; Luminescent Measurements; Materials Testing; Molecular Conformation; Nanotechnology; Nanotubes; Particle Size; Surface Properties

Germanium oxide (GeOx) nanoparticles in the size range from 1.5 to 10 nm were synthesized in a low-pressure premixed H2/O2/Ar flame in the pressure range 25-55 mbar. The flame was doped with different amounts of tetramethylgermanium (Ge(CH3)4) ranging from 500 to 2000 ppm. The influence of process parameters such as pressure, flame coordinate, and cold gas flow velocity with respect to growth of germanium oxide particles were investigated. The formed particles were analyzed in-situ according to their mass and charge by means of a particle mass spectrometer (PMS). The specific surface area was determined ex-situ by the BET method. The crystal structure and chemical composition of the produced nanopowder was characterized by EDX and XRD measurements. Additionally, the particles were analyzed by means of FT-IR spectroscopy.

Topics: Crystallization; Germanium; Materials Testing; Molecular Conformation; Molecular Weight; Nanotechnology; Nanotubes; Particle Size; Surface Properties

Radioarsenic labelled radiopharmaceuticals could be a valuable asset to Positron Emission Tomography (PET). In particular, the long half-lives of (72)As (T(1/2)=26 h) and (74)As (T(1/2)=17.8 d) allow to investigate slow physiological or metabolical processes, like the enrichment and distribution of antibodies in tumor tissue. This work describes the direct production of no-carrier-added (nca) arsenic isotopes *As, with *=71, 72, 73, 74 or 77, the reaction to [*As]AsI(3) and its radiochemical separation from the irradiated solid germanium oxide via polystyrene-based solid-phase extraction. The germanium oxide target, irradiated at a cyclotron or a nuclear reactor, is dissolved in concentrated HF and Ge is separated almost quantitatively (99.97%) as [GeF(6)](2-). [*As]AsI(3) is formed by addition of potassium iodide. The radiochemical separation yield for arsenic is >90%. [*As]AsI(3) is a versatile radioarsenic labelling synthon.

Topics: Arsenic; Germanium; Half-Life; Positron-Emission Tomography; Radioisotopes; Radiopharmaceuticals

The vibrational frequencies and corresponding normal mode assignments of the germanium monoxide tetramer (Ge4O4) in Td symmetry are examined theoretically using the Gaussian03 set of quantum chemistry codes and compared against available experimental data. All normal modes were successfully assigned to one of two types of motion predicted by a group theoretical analysis (Ge-O stretch and Ge-O-Ge bend) utilizing the Td symmetry of the molecule. The molecule possesses a cubane-like structure.

Topics: Germanium; Molecular Conformation; Spectrophotometry, Infrared; Spectrum Analysis, Raman; Vibration

We demonstrate the temperature-dependent growth of germanium oxide and silicon oxide based composite nanostructures (multiple nanojunctions of Ge nanowires and SiO(x) nanowires, Ge-filled SiO(2) nanotubes, Ge/SiO(2) coaxial nanocables, and a variety of interesting micrometer-sized structures), aligned SiO(x) nanowire assemblies, and SiO(x) microtubes. The structures were characterized by SEM, TEM, energy-dispersive X-ray spectroscopy, and electron diffraction. The combination of laser ablation of a germanium target and thermal evaoporation of silicon monoxide powders resulted in the formation of Ge and SiO(x) species in a carrier gas; the nano/micro-sized structures grow by either a Ge-catalyzed vapor-liquid-solid or a Ge-nanowire-templated vapor-solid process.

Topics: Crystallization; Germanium; Metal Nanoparticles; Microscopy, Electron, Transmission; Molecular Conformation; Nanostructures; Nanotechnology; Nanotubes; Nanowires; Semiconductors; Silicon; Silicon Dioxide; Temperature

The use of elemental mass spectrometry as detection for ion chromatography allows sensitive determination of several bromine and iodine species at a reasonable time scale. Lowest concentrations observable are 66 ng L(-1) for bromate, 45 ng L(-1) for iodate, 74 ng L(-1) for bromide and 151 ng L(-1) for iodide. A major drawback of previous IC-ICP-MS applications is the high consumption of time and thus the running costs. The use of GeO2 as internal standard not only allows improved external calibration, but also semiquantitative determination of bromate, bromide, iodate and iodide without any calibration procedure. Furthermore, GeO2 can be used for all known types of anion exchange columns regardless of their construction principles. It is shown, that the analyte-to-GeO2 ratio of four bromine and iodine species was nearly constant over 4 months and almost independent from the ICP-MS instrumental settings. The quantification by means of the analyte-to-GeO2 ratio for samples taken from a bromate round robin test shows that the values obtained are in excellent agreement with calibration curve and isotope dilution results.

Topics: Bromates; Bromides; Germanium; Indicators and Reagents; Iodates; Iodides; Mass Spectrometry; Online Systems; Reference Standards

Previous studies have demonstrated that the erbium:YAG laser is two to three times more efficient for laser lithotripsy than the holmium:YAG laser. However, the lack of a suitable optical fiber delivery system remains a major obstacle to clinical application of Er:YAG laser lithotripsy. This paper describes the initial testing of a hybrid germanium oxide/silica optical fiber for potential endoscopic use with the Er:YAG laser.. Er:YAG laser radiation with a wavelength of 2.94 microm, a pulse energy of 10 to 600 mJ, a pulse length of 220 microsec, and pulse-repetition rates of 3 to 10 Hz was focused into either 350- or 425- microm-core hybrid germanium/silica fibers in contact with human uric acid or calcium oxalate monohydrate stones.. Average Er:YAG pulse energies of 157 +/- 46 mJ (66 J/cm(2)) (N = 8) were delivered at 10 Hz through the 425-microm hybrid fibers in contact with urinary stones before fiber damage was observed. A maximum pulse energy of 233 mJ (98 J/cm(2)) was also measured through the hybrid fiber in contact with the stones. These values are significantly greater than the stone ablation thresholds of 15 to 23 mJ (6-10 J/cm(2)) and the fiber damage thresholds measured for germanium oxide, 18 +/- 1 mJ (13 J/cm(2)), and sapphire, 73 mJ (51 J/cm(2)), optical fibers during Er:YAG laser lithotripsy (P < 0.05).. A prototype hybrid germanium/silica optical fiber demonstrated better performance than both germanium oxide and sapphire fibers for transmission of Er:YAG laser radiation during in vitro lithotripsy.

Topics: Aluminum Oxide; Erbium; Fiber Optic Technology; Germanium; Humans; In Vitro Techniques; Lithotripsy, Laser; Optical Fibers; Silicon Dioxide; Urinary Calculi

We investigated here the combined effect of GeO(2) and radiation on cell viability. Cells were treated with 0 to 22 mM GeO(2) for 12 h followed by 1 Gy X irradiation. A synergistic cytotoxic effect was observed for the combined treatment with a dose-dependent reduction of cell viability. Complete survival curves showed a 2.3- and 2.75-fold increase in radiosensitivity for 50% cell death in the presence of 5 and 15 mM GeO(2), respectively. The increased radiosensitivity also occurred when GeO(2) was given either 4 h prior to irradiation or immediately after radiation exposure. GeO(2) did not affect the total soluble thiol content or the activities of catalase and glutathione S-transferase. Analysis of the production of reactive oxygen species (ROS) revealed that the combined treatment dramatically increased the synthesis of ROS. Addition of N-acetyl cysteine (NAC, 20 mM) decreased the production of ROS in cells. NAC, however, increased cell viability only slightly after treatment with GeO(2) and radiation. Thus increased production of ROS makes little or no contribution to the observed death. The combination of GeO(2) and X radiation, however, significantly increased the frequency of DNA double-strand breaks (DSBs). Notably, the presence of GeO(2) also reduced the efficiency of DNA repair. We conclude that treatment with GeO(2) followed by X irradiation increases DNA DSBs and cell death.

Topics: Acetylcysteine; Animals; Antimutagenic Agents; Catalase; Cell Survival; CHO Cells; Cricetinae; DNA Damage; DNA Repair; Dose-Response Relationship, Drug; Dose-Response Relationship, Radiation; Free Radical Scavengers; Germanium; Glutathione Transferase; Radiation Tolerance; Reactive Oxygen Species; Sulfhydryl Compounds; Time Factors; X-Rays

We report here for the first time that germanium oxide (GeO(2)) blocks cell progression. GeO(2) is not genotoxic to Chinese hamster ovary (CHO) cells and has limited cytotoxicity. However, GeO(2) arrests cells at G2/M phase. The proportion of cells stopped at G2/M phase increased dose-dependently up to 5 mM GeO(2) when treated for 12 h, but decreased at GeO(2) concentration was greater than 5 mM. Analysis of 5-bromodeoxyuridine-labeled cells indicated that GeO(2) delayed S phase progression in a dose-dependent manner, and blocked cells at G2/M phase. Microscopic examination confirmed that GeO(2) treatment arrested cells at G2 phase. Similar to several other events that cause G2 block, the GeO(2)-induced G2 block can also be ameliorated by caffeine in a dose- and time-dependent manner. To explore the mechanism of G2 arrest by GeO(2), cyclin content and cyclin-dependent kinase activity were examined. Cyclin B1 level was not affected after GeO(2) treatment in CHO cells. However, GeO(2) decreased p34(cdc2) kinase (Cdk1) activity. The kinase activity recovered within 9 h after GeO(2) removal and correlated with the transition of G2/M-G1 phase of the cells. This result suggests that GeO(2) treatment reduces Cdk1 activity and causing the G2 arrest in CHO cells.

Topics: Animals; CDC2 Protein Kinase; Cell Cycle; CHO Cells; Colchicine; Cricetinae; Cyclins; Cytotoxins; Dose-Response Relationship, Drug; Drug Interactions; G2 Phase; Germanium; Immunoblotting; Micronucleus Tests; Mitosis; Time Factors

A molecular model was created consisting of leucine enkephalin (a pentapeptide protein) near a germanium dioxide (GeO2) surface surrounded by water molecules. A molecular dynamic (MD) simulation of the system was conducted, and forces exerted by the water on both the surface and the protein were calculated. Orientational and spatial distribution functions of the water were calculated and were examined to determine if structured water existed and how it contributed to the intermolecular forces. Results from the study demonstrated that there is a strong spatial and orientational structuring of water near the GeO2 surface and that it is dependent on the proximity of the protein to the surface. Only minimal structuring occurred near the protein. A linear correlation was observed between the force of water on the protein and the angular distribution of water molecules in the region with the highest spatial density. When the protein is oriented with its polar side toward the GeO2 surface, the water structure near the protein disrupts the typical structure of the water near the surface, causing a force that pushes the protein away from the surface. When the protein is oriented with its non-polar side toward the surface, there is only minimal disruption of the typical water structure, and the resulting net forces between surface and protein are attractive.

Topics: Adsorption; Enkephalin, Leucine; Germanium; Hydrophobic and Hydrophilic Interactions; Models, Molecular; Surface Properties; Thermodynamics; Water

Boron (B)-deficient pumpkin (Cucurbita moschata Duchesne) plants exhibit reduced growth, and their tissues are brittle. The leaf cell walls of these plants contain less than one-half the amount of borate cross-linked rhamnogalacturonan II (RG-II) dimer than normal plants. Supplying germanium (Ge), which has been reported to substitute for B, to B-deficient plants does not restore growth or reduce tissue brittleness. Nevertheless, the leaf cell walls of the Ge-treated plants accumulated considerable amounts of Ge. Dimeric RG-II (dRG-II) accounted for between 20% and 35% of the total RG-II in the cell walls of the second to fourth leaves from Ge-treated plants, but only 2% to 7% of the RG-II was cross-linked by germanate (dRG-II-Ge). The ability of RG-II to form a dimer is not reduced by Ge treatment because approximately 95% of the monomeric RG-II generated from the walls of Ge-treated plants is converted to dRG-II-Ge in vitro in the presence of germanium oxide and lead acetate. However, dRG-II-Ge is unstable and is converted to monomeric RG-II when the Ge is removed. Therefore, the content of dRG-II-Ge and dRG-II-B described above may not reflect the actual ratio of these in muro. (10)B-Enriched boric acid and Ge are incorporated into the cell wall within 10 min after their foliar application to B-deficient plants. Foliar application of (10)B but not Ge results in an increase in the proportion of dRG-II in the leaf cell wall. Taken together, our results suggest that Ge does not restore the growth of B-deficient plants.

Topics: Boric Acids; Boron; Cell Wall; Cucurbita; Germanium; Pectins; Plant Leaves

The purpose of the study was to build up an animal model of mitochondrial myopathy in order to analyse the pathogenesis of the disease.. The skeletal muscles from Wistar rats treated with germanium dioxide for 24 weeks were analysed by histopathologic and electron-microscopic studies. A quantitative analysis was carried out in mitochondrial DNAs of these samples. The biological function of the model was determined.. An animal model of mitochondrial myopathy was built up, in which oxygen free radicals were increased and mitochondrial DNA copies were decreased contrasted with controls.. It suggested that environmental toxin may play a role in the pathogenesis of mitochondrial myopathy. The increase of oxygen free radicals is an important link causing the disease.

Topics: Animals; Disease Models, Animal; DNA, Mitochondrial; Germanium; Male; Mitochondria, Muscle; Mitochondrial Myopathies; Rats; Rats, Wistar; Reactive Oxygen Species

Gap junctional intercellular communication (GJIC) is thought to be essential for maintaining cellular homeostasis and growth control. In order to detect any protective agent against tumor formation, we examined the anticarcinogenic effect of a germanium dioxide (GeO(2)) using a model system of GJIC in F344 rat liver epithelial cells, named WB cells. 12-O-tetradecanoylphorbol-13-acetate (TPA), known as tumor promoters, inhibited GJIC in the epithelial cells as determined by the scrape loading/dye transfer (SL/DT) assay. And GeO(2) recovered this inhibition of GJIC. Immunostaining of connexin 43 (Cx43) protein in WB cells indicated that TPA caused a loss of Cx43 protein from the cell membranes. However, GeO(2) treatment showed re-appearance of Cx43 protein on the membrane. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blots were analyzed to determine whether the test compounds might have altered the steady-state levels of gap junction mRNA and/or connexin protein levels or phosphorylation. The inhibition of GJIC by TPA in WB cells was correlated with the hyperphosphorylation of Cx43 as measured by mobility shifts of the western blot bands of Cx43. TPA induced hyperphosphorylation of Cx43 protein, while GeO(2) appeared to partially block this hyperphosphorylation. Here, we showed that pre- and co-incubation with GeO(2) in TPA-treated WB-cells abolished down-regulation of GJIC by TPA. These data suggest that GeO(2) may inhibit tumor promotion by enhancing GJIC.

Topics: Animals; Anticarcinogenic Agents; Cell Communication; Cell Line; Connexin 43; Connexins; Epithelial Cells; Fluorescent Antibody Technique; Gap Junctions; Germanium; Phosphorylation; Rats; Rats, Inbred F344; Reverse Transcriptase Polymerase Chain Reaction; Tetradecanoylphorbol Acetate

The compound material of nm size particles GeO2-SiO2 was synthesized through hydrolysis of Si(OC2H5)4 and GeCl4 with pH-2. A heat-treatment was carried out for samples at 100-1,200 degrees C in air. Its optical property was determined by UV-Vis spectrum. We have found that the absorption edge of spectrum shifted progressively to longer wavelengths. The quantum size effect of nanocrystals appears because crystals grow and the energy of optical band gap reduces due to the influence of temperature. By the analysis of X-ray diffraction we have observed the process in which the structure of particles changed from disorder into order, and the particles with size 5-10 nm came into obviously as temperature increased until 1,100 degrees C.

Topics: Gels; Germanium; Glass; Nanotechnology; Polymethyl Methacrylate; Silicon Dioxide

Long-term oral ingestion of germanium dioxide (GeO2) causes progressive renal failure derived from tubulointerstitial nephropathy in humans and animals. The characteristic of GeO2-induced nephropathy is the renal tissue injury persisting for a long time, even after cessation of GeO2 ingestion. However, a treatment that can suppress the long-lasting renal tissue injury has not yet been established.. Using the methods of immunohistochemistry and reverse transcription-polymerase chain reaction, we examined the expression of ED1-positive cells (macrophages/monocytes), transforming growth factor (TGF)-beta1 mRNA and protein and collagen type IV mRNA and protein in the kidneys of rats with GeO2-induced nephropathy. Concomitantly, the effects of L-arginine treatment on their expression was explored in the kidneys of rats with GeO2-induced nephropathy.. Chronic administration of GeO2 caused tubulointerstitial nephropathy characterized by leukocyte invasion into the enlarged tubulointerstitial space in rats. The expression of ED1-positive cells, TGF-beta1 protein and collagen type IV protein was markedly increased in the tubulointerstitium of the renal cortex from rats with GeO2-induced nephropathy. Similarly, TGF-beta1 and collagen type IV mRNA were significantly enhanced in the renal cortex of rats with GeO2-induced nephropathy. A small number of tubulointerstitial cells expressing TGF-beta1 protein were also observed in the renal cortex of rats with GeO2-induced nephropathy. However, L-arginine treatment led to a parallel decrease in the expression of ED1-positive cells, TGF-beta1 mRNA and collagen type IV mRNA and protein in rats with GeO2-induced nephropathy.. In general, collagen synthesis is driven by TGF-beta1 in the fibrotic process associated with a variety of renal disorders. TGF-beta1 is secreted by TGF-beta1 producing cells such as macrophages, fibroblasts and myofibroblasts. Thus, the present study indicates that the expression of collagen type IV may be mediated by TGF-beta1 released from invading macrophages and, to a lesser extent, released from tubulointerstitial cells, presumably fibroblasts and/or myofibroblasts in GeO2-induced nephropathy. L-Arginine treatment inhibits collagen type IV synthesis possibly by suppressing macrophage invasion and the resultant TGF-beta1 expression in this nephropathy. L-Arginine treatment may be beneficial in the prevention of tubulointerstitial fibrosis, which is considered to be the terminal stage of GeO2-induced nephropathy.

Topics: Animals; Arginine; Collagen; Female; Germanium; Kidney; Kidney Diseases; Kidney Tubules; Macrophages; Monocytes; Rats; Rats, Wistar; RNA, Messenger; Transforming Growth Factor beta

The purpose of this study were 1) to determine the earliest pathological changes of germanium dioxide (GeO2)-induced myopathy; 2) to determine the pathomechanism of GeO2-induced myopathy; and 3) to determine the minimal dose of GeO2 to induce myopathy in rats. One hundred and twenty five male and female Sprague-Dawley rats, each weighing about 150 gm, were divided into seven groups according to daily doses of GeO2. Within each group, histopathological studies were done at 4, 8, 16, and 24 weeks of GeO2 administration. Characteristic mitochondrial myopathy was induced in the groups treated daily with 10 mg/kg of GeO2 or more. In conclusion, the results were as follows: 1) The earliest pathological change on electron microscope was the abnormalities of mitochondrial shape, size and increased number of mitochondria; 2) The earliest pathological change on light microscope was the presence of ragged red fibers which showed enhanced subsarcolemmal succinate dehydrogenase and cytochrome c oxidase reactivity; 3) GeO2 seemed to affect the mitochondrial oxidative metabolism of muscle fibers; 4) GeO2 could induce mitochondrial myopathy with 10 mg/kg of GeO2 for 4 weeks or less duration in rats.

Topics: Animals; Electron Transport Complex IV; Female; Germanium; Histocytochemistry; Male; Mitochondrial Myopathies; Muscles; Rats; Rats, Sprague-Dawley; Succinate Dehydrogenase

The kinetics of germanium dioxide (GeO2) in single dose and repeated exposures were investigated in male Wistar rats. In the single dose GeO2 (100 mg/kg BW, p.o.) exposure study, values of several kinetic parameters were shown as follows, a maximum concentration in serum of 15.5+/-0.7 microg/ml (mean +/- S.E.M.), an absorption half-life of 0.7+/-0.1 h (mean +/- S.E.M.), an elimination half-life of 2.3+/-0.5 h (mean +/- S.E.M.), a distribution of the central compartment Vp (3.1+/-0.3 1, mean +/- S.E.M.), and the apparent volume of distribution of the tissue compartment Vt (8.5+/-2.9 1, mean +/- S.E.M.). In the repeated exposure study, 730+/-92 mg GeO2 in 1 1 double-distilled H2O ( = 100 mg/kg/day) was given daily to rats for 4 weeks (p.o.). After sacrificing the rats, the analysis of tissue distribution showed that GeO2 was accumulated in some important organs or tissues in the body, especially the peripheral nerves and kidney. These results indicate that GeO2 could be absorbed rapidly but had a longer elimination half-life in rats. In addition, GeO2 was accumulated especially in the nerves and kidney following long-term exposure.

Topics: Animals; Germanium; Half-Life; Male; Rats; Rats, Wistar; Tissue Distribution

Phenylmercury acetate (PMA), which not only causes an elevation of sister chromatid exchanges (SCEs) but also induces high frequency of endoreduplication in human lymphocytes, may be genotoxic to humans. The major aim of our study was to investigate the effects of germanium oxide (GeO2), D-penicillamine (D-PA), dimercaprol (BAL), and diltiazem (DTM) on PMA-induced genotoxicity as quantified by SCEs. All concentrations of the four chemical compounds tested alone did not induce genotoxicity in cultured human lymphocytes. However, GeO2 significantly inhibited PMA-induced genotoxicity in a concentration-dependent manner. Similarly, D-PA at concentrations of 3 microM and 10 microM, and BAL at a concentration of 30 microM produced the antigenotoxic effects. In addition, GeO2 (1.5 microM) significantly reversed an increase of endoreduplication frequency caused by PMA. In a cell cycle kinetic study, GeO2 (0.5-5.0 microM) reversed the inhibition of PMA on the proliferating rate index (PRI) of lymphocytes. On the contrary, both D-PA and DTM at concentrations of 30-300 microM markedly potentiated PMA-induced inhibition of PRI. These findings show that GeO2, D-PA and BAL could antagonize PMA-induced genotoxicity, and GeO2 appears to be the most effective.

Topics: Adult; Antidotes; Antimutagenic Agents; Calcium Channel Blockers; Cells, Cultured; Diltiazem; Dimercaprol; Dose-Response Relationship, Drug; Fungicides, Industrial; Germanium; Humans; Lymphocytes; Male; Mitomycin; Mutagenesis; Nucleic Acid Synthesis Inhibitors; Penicillamine; Phenylmercuric Acetate; Sister Chromatid Exchange

Topics: Germanium; Humans; Kidney; Kidney Diseases; Kidney Failure, Chronic; Male; Middle Aged; Peripheral Nervous System Diseases

A simple correlation between average Na-O bond length and 23Na isotropic chemical shift in crystalline germanates and borates has been established, similar to existing correlations for sodium in silicates and carbonates. This empirical trend is discussed in terms of a decreasing paramagnetic contribution to the chemical shift with increasing average bond length. The correlation is then applied to data for sodium borate and germanate glasses and melts from room temperature to 1200 degrees C, where both structural and compositional effects on the chemical shift are apparent.

Topics: Borates; Chemical Phenomena; Chemistry, Physical; Crystallization; Germanium; Glass; Magnetic Resonance Spectroscopy; Sodium Isotopes

A histopathological study was performed to examine the influence of propagermanium and germanium dioxide (GeO2) on chemically induced renal lesions in rats. Animals were treated with adriamycin or mercuric chloride to induce glomerular or proximal tubular damage, and then given drinking water containing propagermanium (480 or 2,400 ppm solution) or GeO2 (300 or 1,500 ppm solution: equivalent to propagermanium in terms of germanium contents). The distal tubular epithelium after 8 weeks dosage with the 1,500 ppm solution of GeO2 was characterized by vacuolization and deposits of PAS-positive material not only in adriamycin-treated rats, but also in normal rats. In contrast, propagermanium administration was not associated with any alternation in the changes induced by adriamycin or mercuric chloride. We previously clarified that propagermanium had no biochemical influence on the renal function of these renal injured rats. The histological demonstration that this compound does not exert renal toxicity, even when given at a high dosage to renal injured rats, further indicates that it would not exacerbate renal dysfunction already present. This confirms that propagermanium may be a safe compound for use in individuals with compromised kidneys.

Topics: Animals; Doxorubicin; Epithelium; Germanium; Kidney Diseases; Kidney Tubules, Distal; Male; Mercuric Chloride; Organometallic Compounds; Propionates; Rats; Rats, Wistar

Two acute (4 hr) and one subacute (4 wk) inhalation toxicity studies on germanium dioxide (purity > or = 99%, mean particle size 1.7-2.6 microns) were conducted in young adult Wistar rats. In the acute studies, exposure of two groups of five rats of each sex to maximum attainable concentrations of either 3.10 g amorphous or 1.42 g hexagonal germanium dioxide/m3 for 4 hr was not lethal. In the subacute study, four groups of five rats of each sex were exposed to 0, 16, 72 and 309 mg hexagonal germanium dioxide/m3 for 6 hr/day, 5 days/wk during 4 wk. Two additional groups of 5 rats per sex, exposed either to 0 or to 309 mg/m3, were kept for a 33-day post-exposure period. At the end of the treatment period, changes were observed only in rats of the high concentration group: these changes were decreased body weight gain (both sexes), decreases in haematocrit (females) and thrombocyte count (both sexes), and increases in neutrophil count (both sexes) and white blood cell count (females). On clinical chemistry evaluation, decreased fasting blood glucose (females), decreased total protein concentration (both sexes), increased plasma alanine aminotransferase and aspartate aminotransferase activities (females), increased plasma urea nitrogen (males) and increased plasma bilirubin level (females) were observed. In addition, urinary volume was elevated, and urine density and pH were lowered in both sexes. Relative weights of kidneys, spleen, heart and lungs were higher than in controls. Microscopic examination revealed effects on renal tubular epithelium. Effects on growth, kidneys, and liver were still present at the end of the 33-day recovery period. It was concluded that the 4-hr LC50 value of amorphous germanium dioxide was greater than 3.10 g/m3 and that of the hexagonal form greater than 1.42 g/m3. The no-adverse-effect-level in the 4-wk study using hexagonal germanium dioxide was 72 mg/m3.

Topics: Administration, Inhalation; Animals; Body Weight; Dose-Response Relationship, Drug; Female; Germanium; Growth; Kidney; Male; Organ Size; Rats; Rats, Wistar; Sex Factors

We report an experimental model of germanium dioxide (GeO2)-induced neuropathy in rats. More than 6 months administration of GeO2 to young rats produced neuropathy characterized by segmental demyelination/remyelination and nerve edema. Electron microscopic studies demonstrated that changes in Schwann cells, such as an increased cytoplasmic volume or disintegration of the cytoplasm, were the earliest pathological findings. Schwann cell mitochondria contained high electron-dense materials. Subsequent removal of necrotic Schwann cell debris and myelin by invading macrophages was evident. These findings suggested that the Schwann cells themselves are the primary target of the toxin. The deposition of electron-dense granules in the intra-axonal vesicles, which was suggestive of glycogen granules in mitochondria, was observed in the advanced stage of the neuropathy. The findings of endoneurial edema with splitting of myelin lamellae were noted at the early stage of demyelination. Nerve edema may be the result of GeO2-induced endothelial cell injury.

Topics: Animals; Antimutagenic Agents; Cytoplasm; Demyelinating Diseases; Edema; Germanium; Male; Microscopy, Electron; Mitochondria; Myelin Sheath; Rats; Rats, Wistar; Schwann Cells; Sciatic Nerve; Time Factors

The effects of germanium oxide on the genotoxicity of cadmium chloride were investigated. The incorporation of [3H]thymidine into testicular DNA was inhibited in mice injected ip with 1.35, 1.80 or 2.70 mg cadmium chloride/kg body weight. Germanium oxide (0.05 or 0.1 mg/kg body weight, sc) alone did not affect [3H]thymidine incorporation into testicular DNA but 0.05 mg germanium oxide/kg antagonized the inhibitory effect of 1.35 mg cadmium chloride/kg. However, combinations of the other doses of the two compounds did not show statistically significant antagonistic effects. Cadmium chloride significantly increased the frequencies of micronucleus formation in polychromatic erythrocytes, and of chromosome aberrations in the bone marrow of mice treated with 0.7, 1.4 or 2.7 mg/kg body weight, in a dose-related manner. These effects were inhibited by germanium oxide at doses of 0.1 or 0.5 mg/kg body weight, although germanium oxide alone did not affect micronucleus formation or the chromosome aberration rate. Cadmium chloride produced a dose-related increase in the frequency of sister chromatid exchanges in cultured human lymphocytes at concentrations of 5, 10 or 50 mumol. This effect was also inhibited by germanium oxide (0.05 or 0.1 mumol), although germanium oxide alone had no effect. There was a dose-related increase in the frequency of sperms with abnormal head morphologies from mice treated with 0.6, 1.1 or 2.2 mg cadmium chloride/kg body weight and this too was antagonized by the injection of germanium oxide (0.1 or 0.5 mg/kg body weight). Germanium oxide alone did not affect the frequency of sperm-head abnormalities.

Topics: Animals; Antimutagenic Agents; Bone Marrow; Bone Marrow Cells; Cadmium; Cadmium Chloride; Chlorides; Chromosome Aberrations; Chromosomes; DNA; Dose-Response Relationship, Drug; Germanium; Humans; Male; Mice; Mice, Inbred BALB C; Mice, Inbred ICR; Micronucleus Tests; Sister Chromatid Exchange; Sperm Head

A patient with hepatitis B virus-associated cirrhosis manifested various symptoms such as anemia, renal damage and neurological signs including cerebellar ataxia due to long-term administration of germanium-containing food. The patient was a 40-year-old male who had taken germanium containing mineral cheese for 26 months after he was diagnosed as having cirrhosis. Twenty four months after beginning to take the mineral cheese, he began manifesting paresthesia of the extremities, dysarthria and gait ataxia. Laboratory findings revealed anemia and renal damage. Biopsy of the peripheral nerve revealed loss of the large sheathed nerve, a characteristic feature of germanium intoxication. A high concentration of germanium (GeO2) was detected in patient's hair and urine. Cerebellar ataxia was characteristic in this patient, which was not reported in the previous papers.

Topics: Adult; Cerebellar Ataxia; Cheese; Food, Fortified; Germanium; Humans; Liver Cirrhosis; Male

Chronic nephrotoxicity was investigated in rats orally administered germanium dioxide (GeO2) and carboxyethylgermanium sesquioxide (Ge-132) for 24 weeks. Increased BUN and serum phosphate as well as decreased creatinine clearance, weight loss, anemia and liver dysfunction were apparent at week 24 only in the GeO2 treated group. Vacuolar degeneration and granular depositions were observed by light microscope in the degenerated renal distal tubules in the rats of this group, with the semiquantitative scores of tubular degeneration being 95 +/- 9% in the GeO2 group, 3 +/- 1% in the Ge-132 group and 1 +/- 1% in the control group, respectively. Electron microscopy revealed electron-dense inclusions in the swollen mitochondrial matrix of the distal tubular epithelium in the GeO2 group. Although systemic toxicities were reduced after GeO2 was discontinued at week 24, renal tubulointerstitial fibrosis became prominent even at week 40 (16 weeks after discontinuation). A Ge.K alpha X-ray spectrum was clearly demonstrated in the mitochondrial matrix of the distal tubular epithelium in the GeO2 group with the help of electron probe X-ray microanalysis. On the other hand, neither toxic effects nor renal histological abnormalities were manifested in either the Ge-132 or the control group. The renal tissue content of germanium was high at weeks 24 and 40 in the GeO2 group. From these results, it is concluded that GeO2 causes characteristic nephropathy while Ge-132 does not. In addition, it appears that residual GeO2 remains for a considerably long time even after the cessation of GeO2 intake.

Topics: Animals; Electron Probe Microanalysis; Female; Germanium; Kidney Diseases; Kidney Tubules; Microscopy, Electron; Organometallic Compounds; Propionates; Rats; Rats, Inbred Strains; Tissue Distribution

Germanium dioxide is found to increase the frequencies of the genetical transformation in Bacillus subtilis 30-40 fold. The increased frequency of transformation was registered in Sil- mutant in contrast to Sil+ strain having the decreased one. Bacillus megatherium strain KU-2 and Bacillus oligonitrophilus KU-1 were isolated from soil. These strains possess better ability to utilize the orthoclase and biotite. Germanium dioxide did not induce the transformation frequencies increase in these strains. Sil mutant of Bacillus oligonitrophilus demonstrated no competence to transformation.

Topics: Bacillus; Bacillus subtilis; Cell Survival; Genes, Bacterial; Germanium; Mutation; Plasmids; Silicon; Soil Microbiology; Transformation, Genetic

The long-term administration of germanium dioxide (GeO2) to rats produced Ge myopathy characterized by the formation of ragged-red fibers. The earliest pathological changes in experimental Ge myopathy were a decrease in cytochrome c oxidase activity and accumulation of high electron-dense materials in mitochondria. These findings suggest that a mitochondrial dysfunction may be most important in the genesis of experimental Ge myopathy, which could be a useful animal model for the investigation of and therapeutic trials for human mitochondrial myopathies.

Topics: Animals; Germanium; Male; Microscopy, Electron; Muscles; Muscular Diseases; Rats; Rats, Inbred Strains; Time Factors; Vacuoles

The dose dependency of germanium dioxide(GeO2)-induced nephrotoxicity was investigated experimentally in rat groups orally treated with high (150 mg/kg/day), moderate (75 mg/kg/day), or low (37.5 mg/kg/day) doses of GeO2, and in an untreated group. Renal dysfunction, indicated by the increase of blood urea nitrogen and the decrease of creatinine clearance, and systemic toxicity by weight loss, anemia, and hypoproteinemia were more apparent in rats treated with higher dose of GeO2. Urinalysis including daily urinary protein excretion did not reveal any abnormalities in any of the groups. Urinary excretion and renal-tissue content of Ge were significantly elevated in the group of the higher dose of GeO2. Light microscopically, vacuolar degeneration and depositions of granules positive for periodic acid-Schiff in distal tubules were predominant in the higher-dose group of GeO2. The present study demonstrates that GeO2-induced nephrotoxicity develops dose dependently.

Topics: Animals; Blood Urea Nitrogen; Creatinine; Dose-Response Relationship, Drug; Female; Germanium; Kidney; Rats; Rats, Inbred Strains

Chronic renal failure developed in 5 patients who were taking germanium dioxide (GeO2)-containing compounds. Renal functional deterioration was slow but progressive and dialysis treatment was necessitated temporarily in 2 patients. After the discontinuation of GeO2, the impaired renal function tended to improve but remained abnormal for an observation period of 10-40 months. The lack of proteinuria and hematuria was characterized as the clinical manifestations. Renal biopsy specimens revealed the tubular epithelial cell degeneration containing hematoxylin-positive fine granules on light microscopy, and electron-dense inclusions in the swollen mitochondria on electron microscopy. These findings localized mainly in distal segment of the tubules. In the rats given GeO2 orally for 10 weeks, similar histological lesions were evident, as manifested by marked weight loss, anemia, azotemia, and negative proteinuria. In the rats given carboxyethylgermanium sesquioxide, these changes were not observed and Ge concentration of kidney was significantly lower than in the rats given GeO2. The present study indicates that chronic GeO2 intake causes progressive renal dysfunction characterized by the degeneration of distal tubules.

Topics: Adolescent; Adult; Animals; Female; Germanium; Humans; Kidney Failure, Chronic; Male; Middle Aged; Rats; Rats, Inbred Strains

Germanium (Ge; atomic number 32, atomic weight 72.6) belongs to IVb group of the Periodic Table and is found as a trace metal in soil, rocks, plants, and animals. It is widely used in industry because of its semiconductive nature. Some biological activities have been shown in Ge derivatives. Recently, patients with persistent renal damage after chronic ingestion of germanium dioxide (GeO2)-containing compounds have been reported in Japan. This study aimed to investigate subacute nephrotoxicity of GeO2 in Lewis male rats. The rats were treated orally with GeO2 for 13 weeks (GeO2 group) and were compared with those treated with GeO2 for only the first 4 weeks (GeO2-4-week group) and with untreated controls. Renal dysfunction was demonstrated by the increased serum creatinine, BUN, and serum phosphate and decreased creatinine clearance. Liver dysfunction was observed as demonstrated by the increased GOT and GPT, and hypoproteinemia by the decreased total protein and albumin in the GeO2 group. However, daily urinary protein excretion or urinalysis did not differ among the groups. Kidney weight and Ge content of tissues were significantly elevated in the GeO2 group. With the light microscope, vacuoles and the depositions of PAS-stained particles, which correspond to electron-microscopic dense granules in the swollen mitochondria, were predominantly observed in distal tubular epithelium in the GeO2 group. Even in the GeO2-4-week group of rats, serum creatinine was increased and the above-mentioned histological abnormalities were observed, but were less intense.

Topics: Acute Kidney Injury; Animals; Body Weight; Eating; Germanium; Kidney Tubular Necrosis, Acute; Kidney Tubules, Distal; Male; Metabolic Clearance Rate; Microscopy, Electron; Mitochondrial Swelling; Organ Size; Rats

Toxic side effects of germanium dioxide contained in drugs that promote health, include nephropathy, anemia and peripheral neuropathy. Although the neuropathy, which we are interested in, is believed to occur in the patients taking excessive amounts of germanium dioxide, the pathogenesis of such neuropathy is not well understood. Therefore, we studied whether germanium dioxide causes the degeneration of the peripheral nerve in rats and monkeys. Our results showed that in rats, germanium dioxide administered orally and intraperitoneally, 100 mg/kg per day, 3 days a week for 8 weeks and 400 mg/kg per day, once a week for 8 weeks, respectively, did not produce a degeneration of myelinated fibers in teased fiber preparations and Epon-embedded sections of the peripheral nerve. In two monkeys also, germanium dioxide, administered orally, 30 to 40 mg/kg per day, 5 days a week for 8 months, did not produce a degeneration of myelinated fibers of the sural nerve on biopsy, although our results revealed proteinuria and elevated blood urea nitrogen. Further studies are warranted to elucidate the pathogenesis of germanium dioxide induced neuropathy.

Topics: Animals; Germanium; Haplorhini; Nerve Degeneration; Nerve Fibers, Myelinated; Peripheral Nerves; Rats

Topics: Adolescent; Follow-Up Studies; Food, Fortified; Germanium; Humans; Kidney; Kidney Diseases; Male

Topics: Acrolein; Cobalt; DNA Repair; Escherichia coli; Female; Germanium; Humans; Mutagenicity Tests; Mutagens; Mutation; Placenta; Pregnancy; Salmonella typhimurium; Tissue Extracts; Ultraviolet Rays

Topics: Air Pollutants; Animals; Arsenic; Arsenic Trioxide; Arsenicals; Drug Synergism; Germanium; Male; Maximum Allowable Concentration; Oxides; Rats; Sperm Motility; Sulfhydryl Compounds

A germanium compound, germanium oxide (GeO2) behaved as a potent antimutagen on frameshift-type reverse mutations induced by 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) in strains of Salmonella typhimurium TA98 and TA1538 with and without a plasmid pKM101, respectively. This metal antimutagen seems to work independently of the plasmid, a promotive factor in chemically induced mutagenesis through error-prone DNA repair.

Topics: Animals; Biotransformation; Carbolines; Germanium; Indoles; Kinetics; Male; Microsomes, Liver; Mutagenicity Tests; Mutagens; Mutation; Rats; Rats, Inbred Strains; Salmonella typhimurium

A rapid, difference UV spectrophotometric assay of formulated drugs containing a 1,2-diphenolic group is described. In this assay are utilized the bathochromic shift of the absorption band of 1,2-diphenolic substances from approximately 280 to approximately 287 nm and the concomitant hyperchromic effect induced by the addition of germanium dioxide to an aqueous solution of the drug buffered at pH 6. The absorbance of the solution of the complexed drug relative to that of an equimolar solution of the free drug, which is maximum at approximately 292 nm, is proportional to the concentration of the drug and is unaffected by the presence of other UV-absorbing substances in the formulations that lack the 1,2-diphenolic moiety. Applications of the assay are described for formulations containing epinephrine, isoetharine, isoproterenol, levodopa, and methyldopa.

Topics: Catechols; Chemical Phenomena; Chemistry; Germanium; Hydrogen-Ion Concentration; Pharmaceutical Preparations; Solutions; Spectrophotometry, Ultraviolet; Tablets