Formation of Bromate Ion Through a Radical Pathway in a Continuous Flow Reactor

The contribution of ozone and hydroxyl radical to the formation of bromate ion was investigated in a continuous flow reactor. Experiments were conducted under a wide range of ozone dose (0.7 ～ 3.8 mgL), pH (6.5 ～ 8.5), and t-butanol concentration (0 ～ 0.5 mM). The formation of bromate ion was found to depend on radical reaction pathway, because the amount of bromate ion formed increased with pH and decreased with t-butanol, a radical scavenger, even when dissolved ozone concentrations were almost the same. In fact, the amount of bromate ion formed was reduced by 90% in the presence of t-butanol. Furthermore, the formation of bromate ion occurred even when dissolved ozone was not significantly detected in the presence of organic matter (TOC of 1 mgCL). The second-order reaction rate constant of hydroxyl radical with bromide ion, k _HO,Br^? of 1.7 × 10⁹ (M^?1s^?1), was obtained on the assumption that the reactions of bromide ion and t-butanol with hydroxyl radical were competitive with each other in the presence of t-butanol and that the formation of bromate ion depended on the reaction of bromide ion with hydroxyl radical. Therefore, it is concluded that the reaction of bromide ion with hydroxyl radical dominated in the overall reaction from bromide ion to bromate ion in the continuous flow reactor.     

An EMQ-switched CO2 laser as a pump source for afar-infrared laser with a high peak power and a high repetitionrate

A modified current pulsed Q (EMQ)-switched CO₂ laser which is Q-switched by a mechanical beam chopper in combination with a pulsed discharge current is discussed. The laser produces a very stable output with a peak power greater than 1 kW at a repetition rate of 1000 p.p.s. for all transitions in the P and R branches of the CO₂ spectrum. A CH₃F laser pumped by the EMQ-switched laser produces 496 μm radiation in a 6.5 W peak, 100 ns pulses at 500 p.p.s. in the lowest loss EH₁₁ mode     

Crystallins from rat lens are especially susceptible to calpain-induced light scattering compared to other species

PURPOSE: To compare the susceptibility of crystallins from various animal species to formation of light scattering elements after proteolysis by calpain II enzyme (EC 3.4.22.17). METHODS: Lens, total soluble proteins from: 12-day and 4-week old rat, fetal and adult bovine, 16-day embryonic and 10-week chicken, and young human cortex and nucleus were proteolyzed by either endogenous lens calpain or addition of purified calpain II for 24 h followed by incubation for up to 11 days. Absorbance of light at 405 nm estimated light scattering by crystallins; SDS-PAGE and 2D-electrophoresis assessed proteolysis on the crystallins. RESULTS: Most rapid light scattering occurred with total soluble proteins from young rat lens, either after adding purified calpain or by activating endogenous lens calpain with calcium. (Only rat lens showed activation of endogenous calpain II.) beta-crystallin polypeptides from rat, bovine, human, and to a more limited extent, chick lens were partially proteolyzed by addition of purified calpain II. In spite of this proteolysis, total soluble proteins from chicken, bovine, and human lenses showed no obvious light scattering by action of calpain. Crystallins from older rat lens showed approximately 50% of the light scattering displayed by crystallins from younger rats after 3 days, but only when purified calpain was added. CONCLUSIONS: Our results indicate an unusually high susceptibility of crystallin polypeptides from young rat lens to formation of light scattering elements after limited proteolysis. Thus, young rat lens provides a unique opportunity to investigate how properties of crystallins influence the development of light scattering found in cataract.     

Isolation and characterization of high-osmolarity-sensitive mutants of fission yeast

For the fission yeast Schizosaccharomyces pombe, adaptation to high-osmolarity medium is mediated by a mitogen-activated protein (MAP) kinase cascade, involving the Wis1 MAP kinase kinase and the Sty1 MAP kinase. The MAP kinase pathway transduces an osmotic signal and accordingly regulates the expression of the downstream target gene (gpd1(+)) that encodes NADH-dependent glycerol-3-phosphate dehydrogenase, in order to adaptively accumulate glycerol inside the cells as an osmoprotectant. We previously characterized a set of high-osmolarity-sensitive S. pombe mutants, including wis1, sty1, and gpd1. In this study, we attempted to further isolate novel osmolarity-sensitive mutants. For some of the mutants isolated, profiles of glycerol production in response to the osmolarity of the growth medium were indistinguishable from that of the wild-type cells, suggesting that they are novel types. They were classified into three distinct types genetically and, thus, were designated hos1, hos2, and hos3 (high osmolarity sensitive) mutants. One of them, the hos1 mutant, was characterized in detail. The hos1 mutant was demonstrated to have a mutational lesion in the known ryh1(+) gene, which encodes a small GTP-binding protein. Disruption of the ryh1(+) gene results not only in osmosensitivity but also in temperature sensitivity for growth. It was also found that the delta ryh1 mutant is severely sterile. These results are discussed with special reference to the osmoadaptation of S. pombe.     

Analytical model for high-performance shallow-junction-welltransistor (SJET) with a fully depleted channel structure

An analytical model for a very-shallow-junction-well transistor (SJET) is described. Solving the one-dimensional Poisson equation at the channel region, it was found that the channel depletion-layer charge can be reduced by extending the p-n junction depletion layer width between the well region and the substrate in the SJET. Therefore, in the SJET, the p-well thickness and the substrate bias are very important factors for realizing its high performance. According to this model, larger carrier mobility in the inversion layer and smaller subthreshold swing can be realized in the SJET compared to a conventional MOSFET. Moreover, by controlling the electron injection from the inversion layer to the substrate at high substrate bias, a vertical operating mode in the SJET (VSJET) can also be realized     

Extracellular dextran-induced p-nitrophenyl-alpha-D-glucoside-hydrolyzing enzyme of Bacillus circulans KA-304: a producer of Schizophyllum commune-lytic enzyme

We previously reported that centrally administered neuropeptide FF (NPFF) inhibited arginine vasopressin (AVP) release. In this study, immunoneutralization of central NPFF was performed to evaluate the role of endogenous NPFF in the regulation of AVP release. Intracerebroventricular (ICV) injection of antiserum against NPFF (Anti-NPFF) significantly augmented the plasma AVP increase induced by hyperosmolality [intraperitoneal injection of hypertonic saline (600 mOsm/kg, 2% BW)] at 60 min after ICV injection compared with normal rabbit serum (NRS) (NRS: 4.20+/-0.30 pg/ml, Anti-NPFF: 5.83+/-0.46 pg/ml, p < 0.01). Anti-NPFF did not cause significant change in plasma osmolality, plasma volume or arterial blood pressure. This evidence indicates that endogenous NPFF might be physiologically involved in osmoregulation of the plasma AVP level through its inhibitory action.     

Beneficial effect of long-term combined treatment with voglibose and pioglitazone on pancreatic islet function of genetically diabetic GK rats

Vitamin A or its synthetic analogues are potent in controlling cell differentiation and in preventing epithelial cancer in experimental animals. Although some community-based studies have found that high serum retinol levels in prediagnostic sera were associated with reduced risk for cancer, other reports in humans have not confirmed this finding. This study is to evaluate the preoperative serum vitamin A level in breast cancer patients in Taiwan. The serum specimens were collected from 106 female cases of breast cancer (aged 30 to 70 years), 32 female cases of benign breast disease (aged 29 to 57 years), and 40 healthy females (aged 22 to 52 years). The serum vitamin A levels were measured by colorimetic analysis. The results showed the mean value of the vitamin A level was 140.4 +/- 65.7 micrograms/dl in the breast cancer group comparing to 145.2 +/- 44.2 micrograms/dl in the benign breast disease group, 144.0 +/- 30.0 micrograms/dl in the control group (P > 0.05). The characteristics of the breast cancer group were analyzed and they revealed that serum vitamin A levels did not bear statistically significant differences in age, duration, steroid receptor, tumor size and menopausal state. (P > 0.05) In conclusion, the serum vitamin A levels were not decreased in early breast cancer patients. The serum vitamin A levels were significantly decreased in the metastatic breast cancer group, especially in liver metastatic women. (P < 0.05). Postoperative vitamin A supplement may have potential benefit to metastatic breast cancer patients.