bromochloroacetic-acid and titanium-dioxide

Anatase nanocrystals were successfully synthesized and deposited on protein keratin-type wool fibers with good compatibility and significant photocatalytic self-cleaning activity using the sol-gel process. Due to the low chemical resistance and liability to photo-degradation of protein materials, the effect of the acid catalyst used in the sol synthesis was studied. The sols were prepared using oxidizing and non-oxidizing catalysts, nitric acid and hydrochloric acid, respectively, for the hydrolysis and condensation reactions of the titanium dioxide precursor. The size distribution and crystallinity of the sols were characterized by X-ray diffraction spectroscopy and photon correlation spectroscopy. The compatibility of sol formulations and wool is thoroughly compared and discussed by analyzing fibers photo-degradation, surface morphology and self-cleaning properties including stain degradation and colorant decomposition. The UV absorption and mechanical properties of wool fibers before and after coating are also discussed.

Topics: Biocompatible Materials; Catalysis; Feasibility Studies; Hydrochloric Acid; Hydrolysis; Keratins; Nanostructures; Nanotechnology; Oxygen; Phase Transition; Photochemistry; Stress, Mechanical; Titanium; Ultraviolet Rays; X-Ray Diffraction

We report the details of our success in conferring photocatalytic self-cleaning properties on keratin fibers using modified sol-gel colloids. To the best of our knowledge, we studied for the first time the crucial effect of the concentration of titanium dioxide precursor on colloid composition, properties, and biocompatibility in an attempt to enhance the properties and application of anatase titanium dioxide colloid to keratins. The transparency, the particle size distribution, and the crystallinity of synthesized colloids were systematically investigated. The compatibility of the colloids and keratin substrates is thoroughly compared and discussed. The insights presented contribute to the further understanding of the structure-property-use relationship of titanium dioxide in biomaterial applications.

Topics: Biocompatible Materials; Catalysis; Colloids; Keratins; Particle Size; Photochemical Processes; Titanium

In this article, we report an optimization study of a photocatalytic self-cleaning sol-gel formulation. In particular we studied the effect of formulation preparation time on the formation of anatase titanium dioxide sol and its compatibility to protein keratin-type wool fibers. The sols were formed by a low temperature sol-gel process. The nucleated anatase was characterized by UV-vis transmission, particle size distribution, X-ray diffraction, and transmission electron microscopy. The compatibility between the formulations and wool fibers is evaluated by field-emission scanning electron microscopy, UV transmission, and mechanical properties. The photocatalytic self-cleaning activity of coated fibers and its reproducibility are also discussed.

Topics: Animals; Catalysis; Coloring Agents; Keratins; Methylene Blue; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nanotechnology; Particle Size; Photochemistry; Proteins; Spectrophotometry, Ultraviolet; Tensile Strength; Titanium; Wool; X-Ray Diffraction

Using current diagnostic criteria, this work summarizes the microscopic review of 16 proliferative squamous lesions, previously diagnosed as cystic keratinizing squamous cell carcinoma, in the lungs of rats from a 2-year inhalation study with pigment-grade titanium dioxide particles.. In the aftermath of two international pathology workshops designed, in part, to establish histological criteria for classifying pulmonary keratin lesions, these lesions were evaluated by four pathologists using current diagnostic criteria.. Unanimous agreement was reached as to the diagnosis of each of the lesions. Two of the lesions were diagnosed as squamous metaplasia and one as a poorly keratinizing squamous cell carcinoma. The remaining 13 lesions were diagnosed as non-neoplastic pulmonary keratin cysts.. These keratin cysts are a species-specific lesion that is unique to the rat lung under conditions of particle overload exposure.

Topics: Animals; Cysts; Dose-Response Relationship, Drug; Dust; Environmental Exposure; Female; Inhalation Exposure; Keratins; Lung Diseases; Lung Neoplasms; Male; Neoplasms, Squamous Cell; Pulmonary Alveoli; Rats; Species Specificity; Titanium

The present study was performed in order to examine the composition of the connective tissue that forms an attachment to a dental implant. 6 beagle dogs were used. All mandibular premolars were extracted. After 3 months of healing, 6 fixtures--3 in each side of the mandible--(Astra Tech Implants, Dental System TiO blast; Astra Tech AB, Mölndal, Sweden) were installed. After another 3 months of healing, abutment (Uni-abutment 45; Astra Tech AB, Mölndal, Sweden) connection was performed and a plaque control program was initiated. The animals were sacrificed and perfused with a fixative through the carotid arteries. Each implant site, including the implant and the soft and hard peri-implant tissues, was dissected, decalcified in EDTA and further processed using a "fracture technique". The specimens were subsequently embedded in EPON, cut with the microtome set at 3 microm and the sections stained in PAS and toluidine blue. From the EPON-embedded blocks, ultra-thin sections were cut and electron micrographs were prepared. The detailed histologic and morphometrical examinations were restricted to a 200 microm wide zone of connective tissue interposed between the apical border of the junctional epithelium and the bone tissue. In the analysis, this zone was further subdivided into 2 different units; (i) one central, 40 microm wide unit (zone A) located immediately next to the implant surface, and (ii) one lateral, 160 microm wide unit (zone B) that was continuous with the central unit. The implant surface apical of the junctional epithelium and coronal of the bone crest appeared to be in direct contact with a connective tissue. Zone A of this connective tissue was characterized by its (i) absence of blood vessels and (ii) abundance of fibroblasts which were interposed between thin collagen fibers. The more lateral zone B contained comparatively fewer fibroblasts, but more collagen fibers and blood vessels. There are reasons to assume that the fibroblast rich barrier tissue next to the titanium surface plays a rôle in the maintenance of a proper seal between the oral environment and the peri-implant bone.

Topics: Alveolar Process; Animals; Bicuspid; Biocompatible Materials; Collagen; Connective Tissue; Dental Abutments; Dental Implantation, Endosseous; Dental Implants; Dental Plaque; Dogs; Epithelial Attachment; Fibroblasts; Keratins; Mandible; Microscopy, Electron; Mouth Mucosa; Periodontium; Surface Properties; Titanium; Wound Healing