germanium and stannic-oxide

A new method for the site-selective synthesis of nanowires has been developed to enable material growth with defined morphology and, at the same time, different composition on the same chip surface. The chemical vapor deposition approach for the growth of these nanowire-based resistive devices using micromembranes can be easily modified and represents a simple, adjustable fabrication process for the direct integration of nanowire meshes in multifunctional devices. This proof-of-concept study includes the deposition of SnO

Topics: Carbon Monoxide; Electronic Nose; Germanium; Nanowires; Oxides; Particle Size; Surface Properties; Tin Compounds; Tungsten

PET scintigraphy with (68)Ga-labelled analogs is of increasing interest in Nuclear Medicine and performed all over the world. Here we report the characteristics of the eluate of SnO(2)-based (68)Ge/(68)Ga generators prepared by iThemba LABS (Somerset West, South Africa). Three purification and concentration techniques of the eluate for labelling DOTA-TATE and concordant SPE purifications were investigated.. Characteristics of 4 SnO(2)-based generators (range 0.4-1 GBq (68)Ga in the eluate) and several concentration techniques of the eluate (HCl) were evaluated. The elution profiles of SnO(2)-based (68)Ge/(68)Ga generators were monitored, while [HCl] of the eluens was varied from 0.3-1.0 M. Metal ions and sterility of the eluate were determined by ICP. Fractionated elution and concentration of the (68)Ga eluate were performed using anion and cation exchange. Concentrated (68)Ga eluate, using all three concentration techniques, was used for labelling of DOTA-TATE. (68)Ga-DOTA-TATE-containing solution was purified and RNP increased by SPE, therefore also 11 commercially available SPE columns were investigated.. The amount of elutable (68)Ga activity varies when the concentration of the eluens, HCl, was varied, while (68)Ge activity remains virtually constant. SnO(2)-based (68)Ge/(68)Ga generator elutes at 0.6 M HCl >100% of the (68)Ga activity at calibration time and ±75% after 300 days. Eluate at discharge was sterile and Endotoxins were <0.5 EU/mL, RNP was always <0.01%. Metal ions in the eluate were <10 ppm (in total). Highest desorption for anion purification was obtained with the 30 mg Oasis WAX column (>80%). Highest desorption for cation purification was obtained using a solution containing 90% acetone at increasing molarity of HCl, resulted in a (68)Ga desorption of 68±8%. With all (68)Ge/(68)Ga generators and for all 3 purification methods a SA up to 50 MBq/nmol with >95% incorporation (ITLC) and RCP (radiochemical purity) by HPLC ±90% could be achieved. Purification and concentration of the eluate with anion exchange has the benefit of more elutable (68)Ga with 1 M HCl as eluens. The additional washing step of the anion column with NaCl and ethanol, resulted in a lower and less variable [H(+)] in the eluate, and, as a result the pH in the reaction vial is better controlled, more constant, and less addition of buffer is required and concordant smaller reaction volumes. Desorption of (68)Ga-DOTA-TATE of SPE columns varied, highest desorption was obtained with Baker C(18) 100 mg (84%). Purification of (68)Ga-DOTA-TATE by SPE resulted in an RNP of <10(-4)%.. Eluate of SnO(2)-based (68)Ge/(68)Ga generator, either by fractionated elution as by ion exchange can be used for labelling DOTA-peptides with (68)Ga at a SA of 50 MBq/nmol at >95% incorporation and a RCP of ±90%. SPE columns are very effective to increase RNP.

Topics: Gallium Radioisotopes; Germanium; Heterocyclic Compounds, 1-Ring; Isotope Labeling; Peptides; Positron-Emission Tomography; Radioisotopes; Radiopharmaceuticals; Solid Phase Extraction; Tin Compounds

The efficiency of growth of nanocrystalline tin oxide-germania nanocomposites at room temperature was investigated in the presence of the amino acids arginine, histidine, and lysine under varying conditions. The preparation of tin oxide nanoparticles under similar conditions was also examined. It was observed that of the three amino acids, arginine was the most efficient and formed higher yields of the products. Calcination of the products led to crystalline materials. The growth was carried out using a biological approach under mild conditions at room temperature. The morphology and the crystallinity of the products were examined by transmission electron microscopy and atomic force microscopy. The optical properties of the nanocomposites were characterized by fluorescence, and ultraviolet-visible spectroscopy. The nitrogen adsorption studies indicate that the nanocomposites obtained were mesoporous in nature. The nanocomposites exhibited high BET surface area. Such materials could be potentially useful for the development of improved gas sensor devices and optical devices.

Topics: Amino Acids; Arginine; Catalysis; Germanium; Histidine; Lysine; Microscopy, Atomic Force; Microscopy, Electron, Transmission; Nanocomposites; Nanoparticles; Nitrogen; Spectrometry, Fluorescence; Spectrophotometry, Infrared; Spectrophotometry, Ultraviolet; Tin Compounds

Topics: Gallium Radioisotopes; Germanium; Radioisotopes; Radionuclide Generators; Tin; Tin Compounds