A simple and inexpensive microfluidic electrolysis cell

A single channel microfluidic electrolysis cell based on inexpensive materials and fabrication techniques is described. The cell is characterised using the electrochemistry of the Fe(CN)₆³⁻/Fe(CN)₆⁴⁻ couple and its application in electrosynthesis is illustrated using the methoxylation reactions of N-formylpyrrolidine and 4-t-butyltoluene. It is shown that the reactions can be carried out with a good conversion in a single pass. The device, as described, allows the production of several mmol/hour of the methoxylated products.     

Electroreduction of oxygen on sputter-deposited Pd nanolayers on multi-walled carbon nanotubes

The electrochemical reduction of oxygen on Pd nanoparticle/multi-walled carbon nanotube (PdNP/MWCNT) catalysts was studied in acid and alkaline solutions using the rotating disk electrode (RDE) method. The PdNP/MWCNT nanocomposites were prepared by sputter-deposition of palladium onto the surface of MWCNTs. The surface morphology of the PdNP/MWCNT composites was characterised by scanning electron microscopy (SEM). The SEM images showed the formation of Pd nanolayers around MWCNTs. The RDE results revealed a high electrocatalytic activity of PdNP/MWCNT catalysts towards the oxygen reduction reaction (ORR) in alkaline media. Two Tafel regions with different slope can be distinguished. At low overpotentials the Tafel slope is close to −60 mV dec⁻¹ and at higher current densities the slope is approximately −100 mV dec⁻¹. The PdNP/MWCNT composite is a promising material to be used as a cathode catalyst for alkaline membrane fuel cells.     

Scientific and practical approaches to creating ceramic refractory materials and technology

A comprehensive methodological approach is proposed for resolving metallurgical problems within the scope of a multistage problem formula “composition – structure – properties” – “technology” – “thermal shock-corrosion-erosion-resistant material” followed by development of material technology and objects conforming to refractory conditions and operating regimes in heating units. Practical scientific approaches are considered for forming heat and corrosion resistant refractory materials. A general structural model is proposed for ceramic refractory technology making it possible by computer modelling to perform systematic analysis, prediction and calculation of specific technological parameters in the main production stages.     

Modeling and calculation of the temperature fields in two-layer articles

A mathematical model and algorithm for calculation of the temperature fields for two-layer articles are developed. Using the new algorithm a program is created and numerical calculations of the temperature fields that develop in a two-layer article (nonswirl nozzle) in the course of preparation of the pony ladle of a continuous-casting machine for service and in its operating regime are performed. With the use of the program and computer software (in light of experimental results) it becomes possible to perform calculations and predict the sintering mode of ceramic refractory materials as well as optimize the temperature and time heat-treatment diagrams of one-and two-layer articles.     

Heat Shock Proteins Revisited: Using a Mutasynthetically Generated Reblastatin Library to Compare the Inhibition of Human and Leishmania Hsp90s

Thirteen new reblastatin derivatives, with alkynyl, amino and fluoro substituents on the aromatic ring, were prepared by a chemo‐biosynthetic approach using an AHBA(?) mutant strain of Streptomyces hygroscopicus, the geldanamycin producer. The inhibitory potencies of these mutaproducts and of an extended library of natural products and derivatives were probed with purified heat shock proteins (Hsps), obtained from Leishmania braziliensis (LbHsp90) as well as from human sources (HsHsp90). We determined the activities of potential inhibitors by means of a displacement assay in which fluorescence‐labelled ATP competes for the ATP binding sites of Hsps in the presence of the inhibitor in question. The results were compared with those of cell‐based assays and, in selected cases, of isothermal titration calorimetry (ITC) measurements. In essence, reblastatin derivatives are also able to bind effectively to the ATP‐binding site of LbHsp90, and for selected derivatives, moderate differences in binding to LbHsp90 and HsHsp90 were encountered. This work demonstrates that parasitic heat shock proteins can be developed as potential pharmaceutical targets.     

Extraction of high-energy particle beams through the yoke of the synchrocyclotron magnet

A method of obtaining collimated beams of high-energy particles (in particular, pions) is described; this method makes use of the yoke of the synchrocyclotron magnet as the main shield against the direct radiation of the accelerator. The collimators, which are set into channels drilled in the yoke of the magnet, make it possible to obtain beams of pions with energies up to 400 Mev.Deceased.In conclusion, we wish to express our gratitude to A. V. Chestnoi and B. I. Zamolodchikov for valuable advice, to K. A. Baicher and S. I. Zhigoman for drilling the holes in the magnet yoke, and to P. T. Pavlov for the construction of the collimators which were installed in the yoke.     

Intramuscular Exposure to a Lethal Dose of Ricin Toxin Leads to Endothelial Glycocalyx Shedding and Microvascular Flow Abnormality in Mice and Swine

Ricin toxin isolated from the castor bean (Ricinus communis) is one of the most potent and lethal molecules known. While the pathophysiology and clinical consequences of ricin poisoning by the parenteral route, i.e., intramuscular penetration, have been described recently in various animal models, the preceding mechanism underlying the clinical manifestations of systemic ricin poisoning has not been completely defined. Here, we show that following intramuscular administration, ricin bound preferentially to the vasculature in both mice and swine, leading to coagulopathy and widespread hemorrhages. Increased levels of circulating VEGF and decreased expression of vascular VE-cadherin caused blood vessel impairment, thereby promoting hyperpermeability in various organs. Elevated levels of soluble heparan sulfate, hyaluronic acid and syndecan-1 were measured in blood samples following ricin intoxication, indicating that the vascular glycocalyx of both mice and swine underwent extensive damage. Finally, by using side-stream dark field intravital microscopy imaging, we determined that ricin poisoning leads to microvasculature malfunctioning, as manifested by aberrant blood flow and a significant decrease in the number of diffused microvessels. These findings, which suggest that glycocalyx shedding and microcirculation dysfunction play a major role in the pathology of systemic ricin poisoning, may serve for the formulation of specifically tailored therapies for treating parenteral ricin intoxication.     

Sleep patterns and sleep disruptions in school-age children.

This study assessed the sleep patterns, sleep disruptions, and sleepiness of school-age children. Sleep patterns of 140 children (72 boys and 68 girls; 2nd-, 4th-, and 6th-grade students) were evaluated with activity monitors (actigraphs). In addition, the children and their parents completed complementary sleep questionnaires and daily reports. The findings reflected significant age differences, indicating that older children have more delayed sleep onset times and increased reported daytime sleepiness. Girls were found to spend more time in sleep and to have an increased percentage of motionless sleep. Fragmented sleep was found in 18% of the children. No age differences were found in any of the sleep quality measures. Scores on objective sleep measures were associated with subjective reports of sleepiness. Family stress, parental age, and parental education were related to the child's sleep–wake measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterisation of steam-treated nanoporous carbide-derived carbon of TiC origin: structure and enhanced electrochemical performance

Modifications of pore size distribution and structural order of nanoporous carbide-derived carbon (CDC) materials with variety of surface areas and pore sizes were investigated using physical activation by etching with water vapour. Variable etching duration was used to explore the activation impact on the pore size distribution and the adsorption behaviour of TiC-derived carbon. A distribution of micro- and mesopores, modified during physical activation, was studied using N₂ and CO₂ adsorption. Notable impact of preceding carbon structure on the activation product was revealed by the results of scanning electron microscopy, powder X-ray diffraction and Raman spectroscopy. An infrared spectroscopy, energy dispersive spectroscopy and X-ray photoelectron spectroscopy confirmed that water-induced etching of CDC followed by high-temperature treatment in inert gas atmosphere does not change notably the total amount of surface oxygen, however, leads to the changes in a composition of oxygen containing functional groups in post-activated carbon. The electrochemical evaluation was performed in triethylmethylammonium tetrafluoroborate/acetonitrile electrolyte to elaborate the structure-electrochemical properties relationships on post-activated nanoporous CDC materials. It was observed that the degree of improvement in double-layer capacitance achievable with a steam-treatment significantly depends on the preceding properties of CDC prior treatment, whereby the highest capacitance, ~?160 Fg^?1, was reached for the steam-treated TiC-derived CDC made at 800 °C, which clearly is a very promising material for the electrical double-layer capacitor.