Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: KEGG:D01931 (TiO2)
 11,320 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of surface roughness on osteoblast proliferation, differentiation, and protein synthesis was examined. Human osteoblast-like cells (MG63) were cultured on titanium (Ti) disks that had been prepared by one of five different treatment regimens. All disks were pretreated with hydrofluroic acid-nitric acid and washed (PT). PT disks were also: washed, and then electropolished (EP); fine sandblasted, etched with HCl and H2SO4, and washed (FA); coarse sandblasted, etched with HCl and H2SO4, and washed (CA); or Ti plasma-sprayed (TPS). Standard tissue culture plastic was used as a control. Surface topography and profile were evaluated by brightfield and darkfield microscopy, cold field emission scanning electron microscopy, and laser confocal microscopy, while chemical composition was mapped using energy dispersion X-ray analysis and elemental distribution determined using Auger electron spectroscopy. The effect of surface roughness on the cells was evaluated by measuring cell number, [3H]thymidine incorporation into DNA, alkaline phosphatase specific activity, [3H]uridine incorporation into RNA, [3H]proline incorporation into collagenase digestible protein (CDP) and noncollagenase-digestible protein (NCP), and [35S]sulfate incorporation into proteoglycan. Based on surface analysis, the five different Ti surfaces were ranked in order of smoothest to roughest: EP, PT, FA, CA, and TPS. A TiO2 layer was found on all surfaces that ranged in thickness from 100 A in the smoothest group to 300 A in the roughest. When compared to confluent cultures of cells on plastic, the number of cells was reduced on the TPS surfaces and increased on the EP surfaces, while the number of cells on the other surfaces was equivalent to plastic. [3H]Thymidine incorporation was inversely related to surface roughness. Alkaline phosphatase specific activity in isolated cells was found to decrease with increasing surface roughness, except for those cells cultured on CA. In contrast, enzyme activity in the cell layer was only decreased in cultures grown on FA- and TPS-treated surfaces. A direct correlation between surface roughness and RNA and CDP production was found. Surface roughness had no apparent effect on NCP production. Proteoglycan synthesis by the cells was inhibited on all the surfaces studied, with the largest inhibition observed in the CA and EP groups. These results demonstrate that surface roughness alters osteoblast proliferation, differentiation, and matrix production in vitro. The results also suggest that implant surface roughness may play a role in determining phenotypic expression of cells in vivo.
 ...
PMID:Effect of titanium surface roughness on proliferation, differentiation, and protein synthesis of human osteoblast-like cells (MG63). 754 45

We present an investigation of the physico-chemical surface properties of commercially pure titanium coverslips which were submitted to various treatments designed to optimize their topography in view of application in oral implantology. The surface microroughness, chemical composition and water wettability were analyzed on titanium coverslips prepared by mechanical polishing, acid attack in HCl/H2SO4, after mechanical polishing or sandblasting, and titanium plasma-spray. The chemical composition has been measured by Auger electron spectroscopy. The treatments have no major influence on the surface chemical composition and all the samples display a composition approaching that of TiO2 with minor amounts of carbon, sulfur, silicon and calcium as impurities. The roughness has been measured by scanning force microscopy on an area of 20 microns x 20 microns on each sample. Polished titanium is smooth (peak-to-valley roughness 81 nm), whereas the acid-attacked surfaces exhibit a micro-roughness in the microns range (2100 nm for polished and acid attacked; 3600 nm for sandblasted and acid attacked) which is quite reproducible over large areas of the sample. The acid attacked samples present a subsurface layer which contains hydrogen below the native passivating oxide layer. Water wettability measurement shows that all surfaces are hydrophobic with a slightly higher contact angle for the acid attacked surfaces. The different treatments analyzed in this study essentially influence the surface roughness by preserving the chemical composition and the wettability properties of titanium native oxide surface layer.
 ...
PMID:Influence of surface treatments developed for oral implants on the physical and biological properties of titanium. (I) Surface characterization. 958 65

A series of sulfate-doped titania-silica mixed oxides have been prepared by immersing titania-silica gel in the required volume of sulfuric acid, followed by drying. The mixed oxide gel is obtained by hydrolyzing an equimolar mixture of tetraethylorthosilicate (TEOS) and tetrabutylorthotitanate (TBOT) at pH 3. The materials, after calcining at 723 K for 4 h, are characterized by XRD, FT-IR, the BET method, and surface acid strength by the Hammett indicator method. The catalytic activity tests are carried in a fixed bed catalytic reactor (i.d. = 10 mm) for alcohol conversion, whereas cumene cracking/dehydrogenation reactions are carried out in a micropulse reactor. XRD results shows that the titania-silica mixture is amorphous and the crystallization starts with sulfation. The surface of the mixed oxide contains both bridged and normal hydroxyl groups, as observed from FT-IR data. The surface area of the material is not much altered by sulfation and lies within 50 m2/g. The acid strength of 4 wt% SO2-4/TiO2-SiO2 is found to be stronger than that of 100% concentrated H2SO4. In the case of 2-propanol conversion, low acetone selectivity indicates the presence of weak basic sites, whereas methanol conversion over all solids shows that dehydration follows a parallel and consecutive pathway. A good correlation is found between the cumene cracking and the acidity of the catalysts. Copyright 1999 Academic Press.
 ...
PMID:SO2-4/TiO2-SiO2 Mixed Oxide Catalyst, I: Synthesis, Characterization, and Acidic Properties. 1039 70

To further improve the photooxidation techniques for water and waste-water purification, a Ti/TiO2 mesh electrode, was successfully prepared by anodizing Ti mesh in 0.5M H2SO4 solution. The structural and surface morphology of the Ti/TiO2 electrode was examined by Raman spectroscopy and scanning electronic microscopy (SEM) respectively. The examination results indicated that its structure and properties were affected by its growth rate in the anodization process, and anatase TiO2 was dominant in its composition. The photocatalytic (PC) oxidation and photoelectrocatalytic (PEC) oxidation of rhodamine B in aqueous solution using the Ti/TiO2 electrode were investigated and compared. The experimental results demonstrated that the PEC oxidation by applying an electrical bias between the Ti/TiO2 electrode and Pt electrode could significantly enhance the degradation rate of rhodamine B compared with the PC oxidation. It was found that the best performance of PEC oxidation was achieved by applying the electrical bias of 0.6 V. The mechanism of rhodamine B degradation in the PEC process was discussed by studying the changes of absorbance spectrum and proton nuclear magnetic resonance spectroscopy of rhodamine B during the PEC degradation. The experimental results illustrated that both de-ethylation and chromogen destruction of rhodamine B under UV-light irradiation in the PEC degradation took place simultaneously.
 ...
PMID:Photoelectrocatalytic oxidation of rhodamine B in aqueous solution using Ti/TiO2 mesh photoelectrodes. 1184 69

A new type of photoelectrode was innovated by anodising titanium mesh in H2SO4 solution and named Ti/TiO2 mesh electrode. The structural and surface morphology of the Ti/TiO2 mesh was examined by X-ray diffraction, Laser Raman spectra and scanning electronic microscopy (SEM). The results indicated that its crystal structure, morphology and the size of pore were affected greatly by the anodisation voltage, current density. The photoelectrocatalytic (PEC) oxidation of methyl orange (MO) solution using the Ti/TiO2 mesh was investigated. The results demonstrated that Ti/TiO2 mesh prepared at 160 V and 110 mA cm(-2) had the best PEC activity. The PEC oxidation efficiency could be significantly enhanced by applying an optimal electrical bias voltage between the working electrode and counter electrode. It was found that the best performance of PEC oxidation was achieved by applying an electrical bias of 0.6 V. It is suggested that the recombination of electrons and holes was hindered owing to applying electrical bias voltage.
 ...
PMID:An innovative Ti/Tio2 mesh photoelectrode for methyl orange photoelectrocatalytic degradation. 1204 61

The treatment of the simulated wastewater containing formic acid and Cu(II) ions was investigated using photocatalytic technology of immobilized TiO2 film. The technology could efficiently remove COD and Cu(II) from the solution. In parallel, a rapid deactivation for COD removal was observed in a successive batch experiment. By XRD, UV-Vis diffuse reflectance spectra, SEM image and TG analysis, it was inferred that the deactivation was attributed to the shield of the deposited Cu(0) from UV light. The Cu(0)-fouled TiO2 film could be regenerated using three kinds of methods, air oxidation, electrochemical oxidation and air-assisted electrochemical oxidation. The regeneration time was mainly dependent on the used regeneration strategy while the regeneration extent was obviously associated with the tested regeneration medium. For the deactivated film with a relative activity of about 20%, the regeneration time is in order air-assisted electrochemical oxidation < electrochemical oxidation < air oxidation, and HNO3 medium has a regeneration extent of 97.2% for the air-assisted electrochemical oxidation, more desirable than HCl and H2SO4 mediums.
 ...
PMID:Strategies for regeneration of copper(0)-deposited TiO2 photocatalytic film. 1236 45

This work explores the ability of photocatalysis to decontaminate water and air from chemical warfare agent mustard using its simulant 2-phenethyl 2-chloroethyl sulfide (PECES). PECES like mustard slowly dissolves in water with hydrolysis, forming 2-phenethyl 2-hydroxyethyl sulfide (PEHES). Irradiation of TiO2 suspension containing PECES with the unfiltered light of a mercury lamp (lambda > or = 254 nm) decomposed all PECES mostly via photolysis. Reaction under filtered light (lambda > 300 nm) proceeds mainly photocatalytically and requires longer time. Sulfur from starting PECES is completely transformed into sulfuric acid at the end of the reaction. Detected volatile, nonvolatile, surface products, and the suggested scheme of degradation are reported. The main volatile products are styrene and benzaldehyde, nonvolatile--hydroxylated PEHES, surface--2-phenethyl disulfide. Photolysis of PECES produced the same set of volatile products as photocatalysis. Photocatalytic degradation of gaseous PECES in air results in its mineralization but is accompanied by TiO2 deactivation. The highest rate of mineralization with minimum deactivation was observed at about room temperature and a water concentration of 27,500 ppm. No gaseous products except CO2 were detected. The main extracted surface product was styrene. It was concluded that PECES photocatalytic degradation proceeds mainly via C-S bond cleavage and further oxidation of the products. Hydrolysis of the C-S bond was detected only in gas-phase photocatalytic degradation. The quantum efficiency of gas-phase degradation (0.28%) was much higher than that of liquid-phase degradation (0.008%). The results demonstrate the ability of photocatalysis to decontaminate an aqueous and especially an air environment
 ...
PMID:Photocatalytic degradation of 2-phenethyl-2-chloroethyl sulfide in liquid and gas phases. 1252 45

An innovative photoelectrode, TiO2/Ti mesh electrode, was prepared by anodisation. In anodisation, 0.5 mol/L H2SO4 was used as electrolytic solution, the current had been constantly 1A from the beginning of the oxidation until reaching a designed voltage. Results showed that the photocatalytic activity of electrode was better when the designed voltage was 160 V. The morphology and the crystalline texture of the TiO2 film on mesh electrode were examined by scanning electronic microscopy and Raman spectroscopy respectively. The examination results indicated that the structure and properties of the film depended on anodisation rate, and the anatase was the dominant component under the controlled experimental conditions. Degradation of Rhodamine B in photocatalytic (PC) and photoelectrocatalytic (PEC) reaction was investigated.
 ...
PMID:Preparation of TiO2/Ti mesh photoelectrode and properties. 1293 78

A procedure was developed for the rapid analysis of titanium dioxide (TiO2) concentrations in feed and fecal samples. Samples were digested in concentrated H2SO4 for 2 h, followed by addition of 30% H2O2, and absorbance was measured at 410 nm. Standards were prepared by spiking blanks with increasing amounts of TiO2, resulting in a linear standard curve. Complete analysis using this procedure can typically be accomplished within 4.5 h. This procedure was compared to a previously published dry-ash procedure for the analysis of TiO2 in bovine fecal samples. Three sources of OM devoid of TiO2 (a forage sample, a bovine fecal sample without Cr2O3, and a bovine fecal sample containing Cr2O3) were spiked with graded amounts (0, 2, 4, 6, 8, or 10 mg) of TiO2. With our procedure, TiO2 recoveries averaged 96.7, 97.5, and 98.5%, for the three OM sources, respectively, vs. 74.3, 83.8, and 53.1% for the same samples analyzed using the dry-ash method. These results suggest that our procedure is a rapid and accurate alternative to dry-ash procedures for the determination of TiO2.
 ...
PMID:Technical note: a procedure for the preparation and quantitative analysis of samples for titanium dioxide. 1475 60

In this paper, the nano-sized SO4(2-)/TiO2 solid superacid photocatalysts have been prepared by the method of hydrothermal heating the mixed solution of Ti(S04)2 and urea, heating-decomposing, wet impregnating-calcining. The middle products and the ultimate products have been characterized by XRD, BET, FTIR, DRS and FS. The degradation of rhodamine B by photocatalyst was regarded as a model reaction. The optimum condition of preparing SO4(2-)/TiO2 photocatalysts has been chosen. The results show that hydrothermal treating the solution of Ti(SO4)2 can get the anatase nano-sized TiO2 in the weak alkalinity medium; at 300 degrees C by-products of hydrothermal reaction, such as (NH4)2SO4 and so on, can be decomposed by calcining for 4 hours, avoiding much loss of H2SO4; the most important factors that influence the photocatalystic activities of SO4(2-)/TiO2 are the concentration of SO4(2-) on TiO2 and the calcination time. SO4(2-)/TiO2 photocatalysts have the best photocatalystic activities, up to the level of P-25 photocatalyst, when the concentration of SO4(2-) on TiO2 is 11% and the calcination temperature is 450 degrees C.
 ...
PMID:[Spectral studies on nano-sized SO4(2-)/TiO2 photocatalyst prepared by hydrothermal heating the solution of Ti(SO4)2]. 1575 70


1 2 3 4 5 6 Next >>