Integrated carbon composite bipolar plate for polymer–electrolyte membrane fuel cells

The electrical resistance of bipolar plates for polymer–electrolyte membrane fuel cells (PEMFCs) should be very low to conduct the electricity generated with minimum electrical loss. The resistance of a bipolar plate consists of the bulk material resistance and the interfacial contact resistance when two such plates are contacted to provide channels for fuel and air (oxygen) supplies.     

Metabolic profiling of liver from hypercholesterolemic pigs fed rye or wheat fiber and from normal pigs. High-resolution magic angle spinning 1H NMR spectroscopic study

This study presents the first application of a high-resolution magic angle spinning 1H NMR approach to elucidate the metabolic effects of a hypercholesterolemic condition and two high-fiber diets based on rye and wheat bread, respectively, in intact pig liver biopsy samples. Standard 1D and spin-echo 1H spectra were acquired on a total of 20 biopsy samples, and 2D total correlation spectroscopy experiments were carried out on selected samples for assignment of the observed resonances. Principal component analyses and partial least-squares regression discriminant analysis revealed differences in the hepatic lipid content and choline-containing compounds between normal and hypercholesterolemic pigs. In addition, the results demonstrated that the liver metabolite profile of hypercholesterolemic pigs fed a high-fiber rye bread differed from that of pigs fed high-fiber wheat bread with respect to both the lipoprotein fractions and the choline-containing compounds. These findings suggest that earlier reports on high-fiber rye diet-induced effects on plasma HDL/LDL content partially can be ascribed to effects on liver cholesterol metabolism and that the hepatic phospholipase pathways of phosphatidylcholine breakdown are affected by the high-fiber rye diet.     

Study of natural mango juice spoilage and microbial contamination with Penicillium expansum by high resolution H NMR spectroscopy

High resolution ¹H NMR has been applied to monitor the changes in the composition of natural mango juice subjected to spoilage and to microbial contamination with Penicillium expansum. A vast number of compounds undergoing changes upon these processes have been identified and their variations followed throughout time (132 h). Besides the formation of typical fermentation products (e.g. acetate, lactic acid, acetoin and isopropanol/2,3-butanediol) and the utilization of the major sugars (sucrose, glucose and fructose), there were changes in organic acids (e.g. decreases of quinic and shikimic acids with formation of 3,4,5-trihydroxycyclohexane acid in spoiled juice, and decreases of citric and malic acids in contaminated juice), amino acids (decreases of alanine, leucine, isoleucine and valine), and less abundant components such as oligosaccharides and aromatic compounds. The possibility of using these changes as early indicators of natural spoilage or P. expansum contamination is discussed.     

Transient Receptor Potential Channels and Itch

Transient Receptor Potential (TRP) channels are multifunctional sensory molecules that are abundant in the skin and are involved in the sensory pathways of itch, pain, and inflammation. In this review article, we explore the complex physiology of different TRP channels, their role in modulating itch sensation, and their contributions to the pathophysiology of acute and chronic itch conditions. We also cover small molecule and topical TRP channel agents that are emerging as potential anti-pruritic treatments; some of which have shown great promise, with a few treatments advancing into clinical trials—namely, TRPV1, TRPV3, TRPA1, and TRPM8 targets. Lastly, we touch on possible ethnic differences in TRP channel genetic polymorphisms and how this may affect treatment response to TRP channel targets. Further controlled studies on the safety and efficacy of these emerging treatments is needed before clinical use.     

Preparation and characterisation of vanadium catalysts supported over alumina-pillared clays

Supported vanadium-containing catalysts were prepared by impregnation of Al-pillared clays with NaVO₃ precursor aqueous solutions. A montmorillonite and a saponite, both natural as well as previously pillared with Al₁₃-Keggin polycations, were used as supports, being impregnated with solutions of the precursor by means of the incipient wetness technique. The layered structure of the supports is maintained after impregnation, and even after calcination of the impregnated solids at 500 °C, although with a significant worsening of the textural properties of the solids, in particular, a loss of specific surface area. Three crystalline vanadium-containing phases were identified in the impregnated solids, namely, NaV₃O₈, AlVO₄ and V₂O₅ (shcherbinaite). The reduction of these phases to V³⁺ species was observed as wide processes in the 450–750 °C range, all of them centred at ca. 600 °C.     

Water sorption of poly(vinyl alcohol)/ poly(diallyldimethylammonium chloride) interpenetrating polymer network hydrogels

Temperature‐responsive interpenetrating polymer network (IPN) hydrogels constructed with poly(vinyl alcohol) and poly(diallyldimethylammonium chloride) using the sequential IPN method were studied. The characteristics of IPN hydrogels were investigated using the dynamic vapor sorption system. IPN hydrogels exhibited a relatively high sorption ratio, 180–360% at room temperature. The sorption ratio of hydrogels depended on temperature. Diffusion coefficients were calculated according to the Fickian Law at several temperatures. The apparent activation energy was 5.43 kJ mol^?1, which corresponds to typical diffusion processes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1389–1392, 2003