Tailoring and structure of PtRu nanoparticles supported on functionalized carbon for DMFC applications: New evidence of the hydrous ruthenium oxide phase

The influence of the structure and morphology of PtRu nanoparticles supported on functionalized carbon black has been investigated for CO and methanol electrooxidation in a half-cell and in a DMFC single cell. Carbon black was treated with HNO₃ to obtain an oxidized surface (Vulcan-N), and PtRu nanoparticles supported on Vulcan-N were prepared via impregnation, Bönnemann's method and the sulfito-complex route. Temperature programmed reduction (TPR) measurements evidence the presence of RuO₂·xH₂O phase in the catalyst obtained by the sulfito-complex route. This phase was stabilized by metal–support interaction, whereas alloy characteristics were estimated for PtRu catalyst obtained by impregnation and Bönnemann's method. The nature of the precursor–support interaction, induced by the nature of the functional groups on the carbon surface, affects the structure of the electrocatalyst and subsequent behavior in electroactivity. When synthesized through Bönnemann's method, the surface oxygen-containing groups of the support seem to be unable to stabilize the anhydrous precursors of platinum and ruthenium, yielding crystalline RuO₂. Methanol electrooxidation performance was clearly different in the three catalysts, whereas only a few negligible differences were observed in CO oxidation. The superior performance in DMFC of the catalysts obtained by the sulfito-complex route accounts for both the presence of RuO₂·xH₂O species and the functionalization of carbon black.     

Synthesis,Structural Analysis,and Biological Evaluation of Thioxoquinazoline Derivatives as Phosphodiesterase 7 Inhibitors

PDE7 inhibitors regulate pro‐inflammatory and immune T‐cell functions, and are a potentially novel class of drugs particularly useful for treatment of a wide variety of immune and inflammatory disorders. Structural optimization of thioxoquinazoline derivatives led to new compounds with very interesting profiles as PDE7 or PDE7/PDE4 dual inhibitors, which may be further developed as new drugs for inflammatory and neurological diseases.

     

Electrochemical synthesis of NbC–Sn composite powder in molten chloride

NbC–Sn composite powder was successfully prepared from SnO₂, Nb₂O₅ and carbon by electrochemical reduction and carbonization in CaCl₂–NaCl molten salt at 900 °C. The reaction pathway was investigated by terminating electrochemical experiments for various durations. The influence of carbon on the final products was considered. NbC particles were obtained by leaching the composite with acid. The results showed that the aggregated NbC–Sn composite powdev contained NbC particles about 50–100 nm and Sn particles about 200 nm. SnO₂ was reduced to Sn in the sintering process. Nb₂O₅ was electrochemically reduced to Nb in molten salt, experiencing some intermediate products of calcium niobates and niobium suboxides. Nb metal obtained was converted to NbC with assistance of carbon. The reduction of Nb oxides may be incomplete and Nb₃Sn would be formed if carbon is insufficient in the cathodic pellet. NbC with good dispersity is produced by leaching NbC–Sn with HCl.     

Toxicokinetics of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) in the European corn borer,Ostrinia nubilalis (Hübner)

2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), the major hydroxamic acid present in corn, and its tritiated derivative, were prepared synthetically for use in the determination of the toxicokinetics of this insect deterrent in the European corn borer (ECB),Ostrinia nubilalis. In growth studies with DIMBOA (0, 0.05, 0.2, and 0.5 mg/g diet), the mean time to pupation and adult emergence were significantly lengthened by an increase in concentration. Pupal and adult weights, for both female and male, decreased with an increase in concentration. Increased larval and pupal mortality occurred at the highest concentration of DIMBOA. DIMBOA, at concentrations of 0.2 and 0.5 mg/g diet, resulted in a decrease in the number of egg masses produced per female, and at 0.5 mg/g diet, in a decrease in the number of eggs per egg mass. Larvae fed from the neonate stage on a diet containing 0.2 mg [³H]- + [¹H]DIMBOA/g diet showed an increase in the content of label from fourth to fifth instar, but levels declined at pupation and emergence. A large amount of the labeled compounds was excreted by the insect in the pupal case. In dose-related studies, both uptake and excretion increased with an increase in concentration of DIMBOA (0.05, 0.2, 0.4 mg/g diet), while a body burden (concentration in the tissues/concentration in the frass) of approximately 0.25 was maintained for all concentrations. At the highest dose of DIMBOA (0.4 mg/g), the ECB increased consumption, possibly to compensate for the toxic effects of the compound. In topical application studies, elimination of the labeled compound in the frass was rapid, reaching 65% by 4 hr and 88% by 48 hr. Accumulation of label in tissues other than hemolymph was low. The results show that the ECB does possess adaptive mechanisms to deal with the effects of this host-derived compound.     

Intraspecific variation of two components in sex pheromone gland ofPlanotortrix excessana sibling species

Two components, (Z)-5- and (Z)-7-tetradecenyl acetates, in the sex pheromone gland of aPlanotortrix excessana sibling species, were found to vary continuously from a ratio of 397 to 7129 in individual female moths reared from wild larvae collected around New Zealand. Two laboratory colonies were established from populations representing extremes of these ratios. Although both the ratios and the total quantities of the components in individual female moths from both colonies were significantly different from each other, there was a small number of females that overlapped in both ratio and quantity. The variation was confirmed as intraspecific in a field cage experiment with male moths from both populations mating with tethered female moths from both populations.Lepidoptera: Tortricidae: Tortricinae.     

鼠源性抗EHEC O157:H7 Stx2噬菌体Fab抗体库的构建及筛选

目的构建鼠源性抗EHEC O157∶H7 Stx2噬菌体Fab抗体库,并从中筛选特异性的抗体。方法用EHEC O157∶H7 Stx2类毒素免疫BALB/c小鼠,取脾分离淋巴细胞,提取总RNA,RT-PCR分别扩增抗体轻、重链(к和Fd)基因,经双酶切依次克隆入噬粒载体pComb3X中,电转化大肠杆菌XL1-Blue,以辅助噬菌体M13K07进行超感染,构建抗EHEC O157∶H7 Stx2的Fab噬菌体抗体库。以纯化的Stx2为抗原进行筛选,获得抗EHECO157∶H7Stx2的特异性Fab抗体,Western blot法检测噬菌体抗体与毒素抗原的结合活性,并对所得阳性克隆进行基因序列分析。结果构建了一个库容为1.56×107的Fab抗体库,筛选出3株特异性较强的阳性克隆,其中2个可与Stx2A1亚单位抗原反应,1个可与Stx2B亚单位抗原反应。基因序列分析显示,轻、重链可变区氨基酸序列与GenBank中已注册的鼠免疫球蛋白可变区氨基酸序列同源性分别为98.5%和99.6%。结论已成功构建了鼠源性抗EHEC O157∶H7 Stx2噬菌体Fab抗体库,为进一步制备抗EHECO157∶H7Stx2的治疗性人源化抗体奠定了基础。     

普卢利沙星关键中间体的合成研究

用螯合法把化合物6,7-二氟-1-甲基-4-氧代-4H-[1,3]噻嗪并[3,2-a]喹啉-3-羧酸乙酯与三乙酰氧化硼在DMSO中螯合,制得普卢利沙星的关键中间体6,7-二氟-1-甲基-4-氧代-4H-[1,3]噻嗪并[3,2-a]喹啉-3-羧基-O6,O7-二乙酸合硼,考察了不同溶剂、反应温度、反应时间对6,7-二氟-1-甲基-4-氧代-4H-[1,3]噻嗪并[3,2-a]喹啉-3-羧基-O6,O7-二乙酸合硼收率的影响。结果表明,所得产物的质量分数可达99.8%(HPLC归一法),产率97.1%,质量分数和产率都比文献[1~3]报道的高。     

旋毛虫感染诱导的小鼠乳腺癌MCF-7细胞基因表达的变化

目的构建旋毛虫感染诱导的小鼠乳腺癌MCF-7细胞基因表达变化的cDNA消减文库,探讨旋毛虫感染诱导的MCF-7细胞基因表达的变化。方法复制MCF-7细胞小鼠模型,设对照组和旋毛虫感染组(实验组),采用抑制性消减杂交技术构建旋毛虫感染诱导的MCF-7细胞上调基因表达消减文库,并利用反向Northernblot技术对所获得基因的特异性表达进行验证。结果成功构建了旋毛虫感染诱导的MCF-7细胞上调基因表达消减文库,克隆的目的基因片段大小分布在200～500bp之间,20个阳性克隆的测序结果经BLAST比对,获得差异表达的已知功能基因8个和未知功能基因4个,这些基因在小鼠乳腺癌细胞中均有表达,而在肌肉组织中无表达。结论旋毛虫感染诱导的MCF-7细胞差异表达基因上调,其中RB基因可能与乳腺癌细胞的生长抑制密切相关,为在基因水平研究旋毛虫抗肿瘤机理奠定了基础。     

7-去氢胆甾乙酸酯的合成研究

研究7-去氢胆甾乙酸酯的合成方法,以胆甾乙酸酯为原料,经过上溴和脱溴反应制得7-去氢胆甾乙酸酯,用气相色谱法检测7-去氢胆甾乙酸酯的含量,通过7-去氢胆甾乙酸酯的质量变化以及计算从胆甾乙酸酯至7-去氢胆甾乙酸酯的收率来考察上、脱溴反应的选择性。对偶氮化合物和过氧化物化合物自由基引发剂进行选择,最终确定最合适的ABV引发剂,使上、脱溴反应的选择性得到提高。此外．还对上溴反应温度、上溴反应时间以及上溴引发剂的用量进行探讨,确定最佳反应条件。结果表明,脱溴物中7-去氢胆甾乙睃酯的含量由60％提高至70％,从胆甾乙酸酯至7-去氢胆甾乙酸酯的收率由56％提高至69％以上。     

Deposition and characterisation of TiO2 coatings on various supports for structured (photo)catalytic reactors

Different types of aqueous TiO₂–P25 suspensions were prepared and their properties, including rheological behaviour and zeta potential, were studied. Then, TiO₂ suspensions were used to elaborate TiO₂ coatings on various substrates (cordierite monolith, stainless steel plates and -SiC foam) using a dip-coating method. The relationship between the suspension stability and the coating adhesion has been considered. The structural and morphological characterisation of TiO₂ coatings has been performed using scanning electron microscopy, X-ray diffraction and other methods. Finally, the photocatalytic properties of the materials have been determined by studying the photooxidation of aqueous ammonia.