Reduction of Peroxodisulfate at Porous and Crystalline Silicon Electrodes: An Anomaly\ud

Electroluminescence from n-type porous silicon can be generated in solution by reduction of peroxodisulfate. It has been assumed that the SO4•- radical ion, formed in the first reduction step, injects a hole into the valence band of the porous semiconductor. The hole should subsequently undergo radiative recombination with a conduction band electron. Using two techniques, viz., photocurrent quantum efficiency measurements with p-type porous and crystalline silicon electrodes and minority carrier injection studies with the “transistor technique”, we found that the reduction of peroxodisulfate is, however, not always accompanied by hole injection. The silicon results are compared with results obtained on GaAs electrodes. \u

Synthesis and antibacterial effects of cobalt–cellulose magnetic nanocomposites

© The Royal Society of Chemistry. Green synthesis is employed to prepare cobalt/cellulose nanocomposites with cubic (α-cobalt) cobalt as a main component with antibacterial and magnetic properties. An in situ reduction of aqueous solutions of cobalt ions on a model cellulose substrate surface using hydrogen gas affords spherical, cellulose-stabilised cobalt nanoclusters with magnetic properties and an average diameter of 7 nm that are distributed evenly over the surface of the cellulose fibres. These cobalt/cellulose nanocomposites exhibit good antibacterial action against opportunistic pathogens both Gram-positive (S. aureus) and Gram-negative (E. coli, A. baumannii and P. aeruginosa), with zones of inhibition up to 15 mm, thereby encouraging the deployment of these advanced materials for the treatment of wastewater or within medical dressings. This method of preparation is compared with the analogous in situ reduction of cobalt ions on a cellulose surface using sodium borohydride as reducing agent

Основные вехи деятельности Народного управления религиозными делами мусульман Крыма

В статье рассматривается история создания системы народного управления в Крымской АССР, анализируется деятельность мусульманских съездов и уточняется политика советской власти по отношению к мусульманам в рассматриваемый исторический период

Effect of Al substitution on the magnetocaloric properties of La(Fe SiAl)

Here we study the influence of Al doping on the magnetization, heat capacity, and entropy change of La(FeSiAl ) where x = 0, 0.048, and 0.081. When x = 0, the system shows a remarkably sharp heat capacity feature associated with spin fluctuations coincident with, but quite distinct from the latent heat spike of the first order paramagnetic to ferromagnetic phase transition. With the addition of Al the magnetic and calorimetric features become more distributed in field, suggesting that Al adds disorder to the system. For both finite x compositions studied here, the latent heat disappears and the transition can be classified as second order. Although the entropy change associated with the transition is reduced once Al is substituted for Si, the adiabatic temperature change, ΔT is still significant. In La(Fe [Al) the balance between changes in the field dependence of the heat capacity with respect to overall ΔT gain is highlighted, showing that a small amount of Al doping clearly offers some advantage for application

Tunable supramolecular gel properties by varying thermal history

YesThe possibility of using differential pre‐heating prior to supramolecular gelation to control the balance between hydrogen‐bonding and aromatic stacking interactions in supramolecular gels and obtain consequent systematic regulation of structure and properties is demonstrated. Using a model aromatic peptide amphiphile, Fmoc‐tyrosyl‐leucine (Fmoc‐YL) and a combination of fluorescence, infrared, circular dichroism and NMR spectroscopy, it is shown that the balance of these interactions can be adjusted by temporary exposure to elevated temperatures in the range 313–365 K, followed by supramolecular locking in the gel state by cooling to room temperature. Distinct regimes can be identified regarding the balance between H‐bonding and aromatic stacking interactions, with a transition point at 333 K. Consequently, gels can be obtained with customizable properties, including supramolecular chirality and gel stiffness. The differential supramolecular structures also result in changes in proteolytic stability, highlighting the possibility of obtaining a range of supramolecular architectures from a single molecular structure by simply controlling the pre‐assembly temperature.FP7 Ideas: European Research Council. Grant Number: 25877

Identification of oligomerization and drug-binding domains of the membrane fusion protein EmrA

Many pathogenic Gram-negative bacteria possess tripartite transporters that catalyze drug extrusion across the inner and outer membranes, thereby conferring resistance. These transporters consist of inner (IMP) and outer (OMP) membrane proteins, which are coupled by a periplasmic membrane fusion (MFP) protein. However, it is not know whether the MFP translocates the drug between the membranes, by acting as a channel, or whether it brings the IMP and OMP together, facilitating drug transfer. The MFP EmrA has an elongated periplasmic domain, which binds transported drugs, and is anchored to the inner membrane by a single -helix, which contains a leucine zipper dimerization domain. Consistent with CD and hydrodynamic analyses, the periplasmic domain is predicted to be composed of a -sheet subdomain and an -helical coiled-coil. We propose that EmrA forms a trimer in which the coiled-coils radiate across the periplasm, where they could sequester the OMP TolC. The "free" leucine zipper in the EmrA trimer might stabilize the interaction with the IMP EmrB, which also possesses leucine zipper motifs in the putative N- and C-terminal helices. The -sheet subdomain of EmrA would sit at the membrane surface adjacent to the EmrB, from which it receives the transported drug, inducing a conformational change that triggers the interaction with the OMP

High Pressure Processing of Dairy Foods

End of Project ReportThe term High Pressure Processing (HPP) is used to describe the technology whereby products are exposed to very high pressures in the region of 50 - 800 MPa (500 - 8000 Atmospheres). The potential application of HPP in the food industry has gained popularity in recent years, due to developments in the construction of HPP equipment which makes the technology more affordable. Applying HPP to food products results in modifications to interactions between individual components, rates of enzymatic reactions and inactivation of micro-organisms. The first commercial HPP products appeared on the market in 1991 in Japan, where HPP is now being used commercially for products such as jams, sauces, fruit juices, rice cakes and desserts. The pioneering research into the application of HPP to milk dates back to the end of the 19th century. Application of HPP to milk has been shown to modify its gel forming characteristics as well as reducing its microbial load. HPP offers the potential to induce similar effects to those generated by heat on milk protein. Recent reports have also indicated that HPP could accelerate the ripening of cheese. Much of the Irish cheese industry is based on the production of Cheddar cheese, the ripening time for which can vary from 4 - 12 months or more, depending on grade. A substantial portion of the cost associated with Cheddar manufacture is therefore attributed to storage under controlled conditions during ripening. Thus, any technology which may accelerate the ripening of Cheddar cheese while maintaining a balanced flavour and texture is of major economic significance. While food safety is a dominant concern, consumers are increasingly demanding foods that maintain their natural appearance and flavour, while free of chemical preservatives. HPP offers the food industry the possibility of achieving these twin goals as this technology can lead to reduced microbial loads without detrimentally effecting the nutritional or sensory qualities of the product. The development of food ingredients with novel functional properties offers the dairy industry an opportunity to revitalise existing markets and develop new ones. HPP can lead to modifications in the structure of milk components, in particular protein, which may provide interesting possibilities for the development of high value nutritional and functional ingredients. Hence these projects set out to investigate the potential of HPP in the dairy industry and to identify products and processes to which it could be applied.Department of Agriculture, Food and the Marin

Phenotypic Diversity for Seed Mineral Concentration in North American Dry Bean Germplasm of Middle American Ancestry

Dry bean (Phaseolus vulgaris L.) seeds are a major protein, carbohydrate, and mineral source in the human diet of peoples in multiple regions of the world. Seed mineral biofortification is an ongoing objective to improve this important food source. The objective of this research was to assess the seed mineral concentration of five macroelements and eight microelements in a large panel (n = 277) of modern race Durango and race Mesoamerica genotypes to determine if variability existed that could be exploited for targeted seed biofortification. Varieties that derive from these races are found in many diets throughout the world. The panel was grown in replicated trials under typical production conditions in the major bean growing regions of the United States, and a subset of the panel was also grown in replicated trials at three locations under control and terminal drought conditions. Except for K, seed mineral concentrations were higher for race Mesoamerica genotypes. Significantly higher seed concentrations for the majority of the minerals were observed for white-seeded genotypes and race Durango genotypes with the now preferred indeterminate, upright growth habit. Modern genotypes (since 1997) had equal or increased mineral concentrations compared with older genotypes. Drought affected mineral content differentially, having no effect on the microelement content but increased Co, Fe, and Ni concentrations. The correlation of Ca and Mn concentrations suggests that these elements may share seed deposition mechanisms. The high heritability for seed mineral concentration implies that breeding progress can be achieved by parental selection from this panel

Characterisation of haematological profiles and whole blood relative gene expression levels in Holstein-Friesian and Jersey bull calves undergoing gradual weaning

peer-reviewedHaematological profiles indicate the health status of an animal and can be used to identify sub-clinical stress responses. The objectives of the study were to examine (i) the effect of breed and plane of nutrition, on haematological profiles of artificially reared Holstein-Friesian and Jersey bull calves in response to gradual weaning, and (ii) the effect of breed on immune response genes in bovine whole blood using real-time quantitative PCR. Holstein-Friesian and Jersey bull calves were group housed indoors and individually fed using an automatic feeder. They were allocated to a high, medium or low plane of nutrition, based on milk replacer (MR) and concentrate. The nutrition treatments were calculated using National Research Council guidelines in order to achieve a high, medium or low growth rate for each respective breed. During the weaning phase MR was gradually reduced over a 14-day (d) period (d −13 to d 0). Calves were blood sampled on d −14, −6, −3, 0, 1, 3, 8 and 14 relative to weaning (d 0) for subsequent haematological analysis. On d −14, 1 and 8, a subset of eight Holstein-Friesian calves randomly selected from the medium nutrition treatment and eight Jersey calves randomly selected from the high nutrition treatment, were blood sampled for gene expression profiling, targeting biomarkers of weaning stress. These two treatment groups were chosen to examine the effect of breed on expression of the genes of interest, as energy intake and animal performance were similar. There was no effect of breed×plane of nutrition interaction nor effect of plane of nutrition on any variable measured (P>0.05). Gradual weaning produced differential biological responses in the two breeds evidenced by breed×time interactions for lymphocyte, monocyte and red blood cell number, plasma haemoglobin and haptoglobin concentrations (P<0.05). The typical stress response consisting of neutrophilia and lymphopaenia was not observed for any treatment. An immune response to gradual weaning was observed as the relative gene expression level of the pro-apoptotic gene, Fas, increased on d 1 relative to d −14 (P<0.05). Relative gene expression levels were greater in Jersey calves compared with Holstein-Friesian for the pro-inflammatory cytokine CXCL8 (P=0.05) and the glucocorticoid receptor, GRα (P<0.05). The increased levels of these transcripts suggest that Jersey calves may have a more sensitive immune system compared with Holstein-Friesian