Charge-transfer chromatographic study of the complex formation of some steroidal drugs with carboxymethyl-gamma-cyclodextrin

Methyl tert-butyl ether (MTBE) is a widely used gasoline oxygenate. Two other ethers, ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME), are also used in reformulated gasoline. Inhalation is a major route for human exposure to MTBE and other gasoline ethers. The possible adverse effects of MTBE in humans are a public concern and some of the reported symptoms attributed to MTBE exposure appear to be related to olfactory sensation. In the present study, we have demonstrated that the olfactory mucosa of the male Sprague-Dawley rat possesses the highest microsomal activities, among the tissues examined, in metabolizing MTBE, ETBE, and TAME. The metabolic activity of the olfactory mucosa was 46-fold higher than that of the liver in metabolizing MTBE, and 37- and 25-fold higher, respectively, in metabolizing ETBE and TAME. No detectable activities were found in the microsomes prepared from the lungs, kidneys, and olfactory bulbs of the brain. The observations that the metabolic activity was localized exclusively in the microsomal fraction, depended on the presence of NADPH, and was inhibitable by carbon monoxide are consistent with our recent report on MTBE metabolism in human and mouse livers (Hong et al., 1997) and further confirm that cytochrome P450 enzymes play a critical role in the metabolism of MTBE, ETBE, and TAME. The apparent K(m) and Vmax values for the metabolism of MTBE, ETBE, and TAME in rat olfactory microsomes were very similar, ranging from 87 to 125 microM and 9.8 to 11.7 nmol/min/mg protein, respectively. Addition of TAME (0.1 to 0.5 mM) into the incubation mixture caused a concentration-dependent inhibition of the metabolism of MTBE and ETBE. Coumarin (50 microM) inhibited the metabolism of these ethers by approximately 87%. Further comparative studies with human nasal tissues on the metabolism of these ethers are needed in order to assess the human relevance of our present findings.     

Relationship between retention characteristics and physicochemical parameters of solutes on porous graphitized carbon column

The retention of 44 barbituric acid derivatives was determined on porous graphitized carbon (PGC) column using dioxane water mixtures as eluents. Linear correlations were calculated between the logarithm of the capacity factor and the dioxane concentration in the eluent. Free Wilson analysis combined with stepwise regression analysis was used to elucidate the role of individual substituents in the retention behaviour. Calculations indicated that the apolar substituents lie parallel to the surface of PGC surface increasing in this manner the retention and--as opposed to the retention characteristics of traditional reversed-phase supports--the position of substituents also exerts a marked influence on the retention.     

Salivary sialic acid and cancer

In this preliminary study the salivary sialic acid levels in 56 randomly selected cancer patients of different ages were compared with those of 70 healthy controls of similar age distribution. The cancer patients consisted of 25 women and 31 men. Twenty were suffering from lung cancer. Unstimulated whole saliva was collected by expectoration. The mean sialic acid levels were 185 +/- 22.8 mg/dl in the cancer group and 6.2 +/- 3.72 mg/dl in the controls and the difference between them was significant (p < 0.0001). The subjects were also grouped according to age and cancer type. However there were no significant differences in sialic acid levels between these.     

Blast colony forming cells in umbilical cord blood: frequency and correlation to other haemopoietic progenitors

Streptomycin-treated adult mice were investigated as a possible model for studying the enteropathogenicity of Aeromonas species. C57BL mice pre-treated with streptomycin (5.0 g/L drinking water, 48 hours) received a single intragastric dose (10(10) bacteria /10.5 mL) of one of six well-characterized, toxin-producing, human diarrhoeal isolates of A. veronii biovar sobria (n = 3) or A. hydrophila (n = 3). Their faeces were examined for Aeromonas for 10 days post-challenge. All strains colonized the antibiotic-treated mice. Colonization did not occur in mice which did not receive streptomycin. Strains of A. hydrophila were recovered in greater numbers than strains of A. veronii biovar sobria, and colonized ( > or = 10(3) cfu/g of faeces) a greater proportion of mice at day 10. Strains of the latter species, however, were more adherent in cell line assays used as models of intestinal adhesion. A. hydrophila strains localized in the large intestine and appeared not to be cell associated. This study, therefore, points to species-related differences in intestinal colonization mechanisms. The streptomycin-treated adult mouse model may prove useful for further investigation of some of these mechanisms. Diarrhoeal symptoms were, however, not produced in this model.     

A piloting plane for controlling wireless devices

The development of the IEEE wireless technologies is promising the ultimate Internet service deployment on wireless and mobile infrastructures since they would offer larger bandwidth at cheaper price. However, it is disquieting to see that the different control algorithms supposed to be the heart of the wireless deployment are not evolving as fast as the wireless technologies do. Here we come up with the hard question: how to pilot these control algorithms? This paper is proposing a revolutionary tyre where all control algorithms are fed in a concerted manner by a self-steering system. In network terms, this paper is proposing a definitely new technology that will permit to optimize, secure, manage and control the wireless devices using an automatic pilot system.     

Radiologic evaluation of gastrointestinal leiomyosarcomatosis

A 68-year-old woman who had previously undergone small intestinal resection because of leiomyosarcoma was referred to our clinic with epigastric pain. A double-contrast barium study and the subsequent abdominopelvic CT and abdominal MRI examinations demonstrated multiple extraluminal growing tumors arising from the walls of stomach, small bowel, and colon. A CT-guided aspiration biopsy revealed malignant mesenchymal tumor. The presence of disseminated intra-abdominal masses without concomitant ascites and invasion of tissue planes on CT in a patient operated on prior because of a leiomyosarcoma led to the diagnosis of gastrointestinal leiomyosarcomatosis. In this report we discuss the radiological approach to this rare entity.     

基于组件的三维CAD系统开发的关键技术研究

研究子组件技术和特征造型技术 ,并以“金银花”系统的开发为实例对基于组件开发三维 CAD系统的相关技术和实现方法进行了深入研究 ,给出了实现系统的框架结构和组件结构。     

Relation between potential and catalytic activity of rhodium in propylene combustion

The relation between the catalyst potential and the catalytic performance has been investigated in the gas-phase combustion of propylene with oxygen over rhodium catalysts at 375 °C. The rhodium catalyst, deposited on yttria-stabilized zirconia (YSZ) solid electrolyte, also served as working electrode in the electrochemical cell. Under open-circuit conditions, the measured catalyst potential was found to be a sensitive indicator of the oxidation state of the rhodium catalyst, which influences the catalytic reaction rate dramatically and depends strongly both on the method of catalyst film preparation and on the composition of the reacting gas mixture. In turn, under closed-circuit conditions, the applied catalyst potential is a convenient tool to maintain the catalyst in its more active, reduced form and to control its catalytic performance. The activity of atomic oxygen at the three-phase boundary (tpb) during open-circuit catalytic reaction was estimated from solid electrolyte potentiometric (SEP) measurements, in good agreement with the average surface oxidation state obtained from XRD and XPS analyses. O/Rh atomic ratios higher than stoichiometric were found by XPS at the outer surface of the catalysts suggesting a strong open circuit O^2– spillover due to strong metal support interactions (SMSI) and a concomitant extension of the electric double layer to the gas-exposed catalyst surface, similarly to emersed electrodes in aqueous electrochemistry. Applying potentials up to several hundreds of mV, highly nonfaradaic promotion of propylene combustion was achieved. Electrochemical promotion of catalysis (EPOC) was most efficient at stoichiometric gas composition, that is, close to the limit of surface reduction, and with the catalyst exhibiting the smallest O^2– spillover population at open-circuit conditions.     

Fe2+液相催化氧化脱除烟气中SO2

提出了一种烟气脱硫新工艺。实验选用水作脱硫剂 ,在只以Fe为催化剂的条件下进行。加入吸收液槽中的铁屑可与脱硫产生的稀硫酸进行反应 ,不仅可维持较高的吸收液pH值 ,而且产生的Fe2 + 引发了液相催化氧化SO2 反应。连续运行实验结果表明脱硫过程在不同阶段分别受SO2 溶解、Fe2 + 液相催化氧化SO2 反应、气相中SO2 扩散和铁屑与酸反应控制。吸收液中Fe2 + 质量浓度的变化和初始Fe2 + 质量浓度对脱硫率及吸收液pH值影响显示 ,可直接由清水制取高浓度硫酸亚铁溶液。实验还调查了SO2 入口质量浓度、液气比、空塔气速和吸收温度对脱硫率和吸收液pH值的影响     

Effect of the solid precursors on the formation of nanosized TiBx powders in RF thermal plasma

Continuous synthesis of TiB_x (x≈0.5–2) nanoparticles from various low cost solid precursors such as titanium and titanium dioxide admixed with boron and/or carbon in radiofrequency thermal plasma was studied. Feasibility of TiB₂ formation was predicted by thermodynamic equilibrium calculations in the 500–5000 K temperature range. In all the investigated system high temperature reactions resulted in nanometer-sized TiB_x powders with a mean size varying between 13 and 83 nm. The yield of particular runs ranged from 38% to 97%. Among the synthesized products in addition to TiB_x, oxidized precursor residues were also found in smaller quantities. Although addition of carbon to the precursors could not completely prevent surface oxidation of boride particles, it contributed to the reduction of the mean particle size of the formed TiB₂.