The adsorption and photocatalytic degradation of Ethyl methylphosphonate (EMPA) on powdery TiO2 film has experimentally investigated using attenuated total reflection-infrared Fourier transform spectroscopy (ATR-FTIR) in ambient condition. Characteristic IR frequency as P-O-C vibration mode as EtO was observed by EMPA adsorbed at the surface of TiO2. By TiO2 photocatalysis, the adsorbed EMPA was decomposed to methyl phosphonic acid and phosphoric acid. The increment of IR intensity of which is assigned to Ti–O-P-O-Ti of EMPA was accompanied with increasing the IR peak intensity assigned to MPA. About that, we suggest that the appearance of the Ti–O-P-O-Ti of EMPA by the TiO2 photocatalysis is regarded as acceleration of the hydrolysis of EMPA by the surface OH groups of TiO2. The plausible adsorption structure and the photocatalytic reaction mechanism of EMPA at the surface of TiO2 photocatalyst were elucidated.
Geometric structures and excited-state proton dislocation of size-selected salicylic acid clusters (salicylic acid and 5-methoxysalicylic acid) with water were studied by using laser spectroscopic techniques. Fluorescence excitation, dispersed fluorescence, and infrared (IR) spectra of those clusters in supersonic jets were examined for both the electronic ground (S0) and first excited (S1) states. The geometric structures of the clusters were determined on the basis of the IR spectra of the OH stretch region with the help of quantum chemical calculations. The hydroxyl group of the water moiety in the clusters forms a ring involving the carboxylic group of the salicylic acid moiety. The IR spectra in S0 show that the intramolecular hydrogen bond in the salicylic acid moiety is still held upon cluster formation, but the phenolic OH stretch band intensity is remarkably weaken in the clusters. The IR spectra in the S1 state and dispersed fluorescence spectra indicated that the intramolecular excited state proton dislocation is hardly affected by the microsolvation with water, in contrast with the strong suppression of the dislocation in the self-solvation. 相似文献
A fast disintegrating compressed tablet was formulated using amino acids, such as L-lysine HCl, L-alanine, glycine and L-tyrosine as disintegration accelerator. The tablets having the hardness of about 4 kgf were prepared and the effect of amino acids on the wetting time and disintegration time in the oral cavity of tablets was examined on the basis of surface free energy of amino acids. The wetting time of the tablets increased in the order of L-lysine HCl, L-alanine, glycine and L-tyrosine, whereas the disintegration time in the oral cavity of the tablets increased in the order of L-alanine, glycine, L-lysine HCl and L-tyrosine. These behaviors were well analyzed by the introduction of surface free energy. When the polar component of amino acid was large value or the dispersion component was small value, faster wetting of tablet was observed. When the dispersion component of amino acid was large value or the dispersion component was small value, faster disintegration of tablet was observed, expect of L-tyrosine tablet. The fast disintegration of tablets was explained by the theory presented by Matsumaru. 相似文献
A co-cross-linking reaction of bio-based multi-functional epoxides (1) derived from limonene oxide and bisphenol A diglycidyl ether (BPADE) in the presence of 2-ethyl-4-methylimidazole (EMI) as a cross-linker afforded the corresponding network copolymers (2) having the 10% thermal decomposition temperature (Td10) of 294.4?°C at maximum. Adhesive strength induced by 1, especially tetra-functional epoxide, and BPADE exhibited remarkably higher than that by BPADE alone. 相似文献
The UVA is currently thought to be carcinogenic because, similar to UVB, it induces the formation of cyclobutane pyrimidine dimers (CPDs). Various drugs have been reported to cause photosensitive drug eruptions as an adverse effect. Although the precise mechanism of photosensitive drug eruption remains to be elucidated, it is generally accepted that free radicals and other reactive molecules generated via UV‐irradiated drugs play important roles in the pathogenesis of photosensitive drug eruptions. The waveband of concern for photo‐reactive drugs is UVA‐visible light, but some extend into the UVB region. We tested whether photosensitive drugs could enhance CPD formation after UVA exposure by using isolated DNA in the presence of several reported photosensitive drugs using high‐performance liquid chromatography. We found that the diuretic agent hydrochlorothiazide (HCT) significantly enhanced the production of TT dimers over a wide range of UVA. Furthermore, we investigated whether UVA plus HCT could enhance CPD production in xeroderma pigmentosum model mice defective in nucleotide excision repair. Immunofluorescence studies showed that CPD formation in the skin significantly increased after 365 nm narrow‐band UVA irradiation in the presence of HCT, compared with that in wild‐type mice. HCT could be used with caution because of its enhancement of UVA‐induced DNA damage. 相似文献
We previously found that some Saccharomyces cerevisiae and Lactobacillus plantarum remarkably formed mixed-specie biofilm in a static co-culture and deduced that this biofilm had potential as immobilized cells. We investigated the application of mixed-specie biofilm formed by S. cerevisiae BY4741 and L. plantarum HM23 for ethanol fermentation in repeated batch cultures. This mixed-specie biofilm was far abundantly formed and far resistant to washing compared with S. cerevisiae single biofilm. Adopting mixed-specie biofilm formed on cellulose beads as immobilized cells, we could produce enough ethanol from 10 or 20 % glucose during ten times repeated batch cultures for a duration of 10 days. Cell numbers of S. cerevisiae and L. plantarum during this period were stable. In mixed-specie biofilm system, though ethanol production was slightly lower compared to S. cerevisiae single-culture system due to by-production of lactate, pH was stably maintained under pH 4 without artificial control suggesting high resistance to contamination. Inoculated model contaminants, Escherichia coli and Bacillus subtilis, were excluded from the system in a short time. From the above results, it was indicated that the mixed-specie biofilm of S. cerevisiae and L. plantarum was a promising immobilized cell for ethanol fermentation for its ethanol productivity and robustness due to high resistance to contamination. 相似文献