First Principles Study of Structural, Electronic and Magnetic Interplay in Ferroelectromagnetic Yttrium Manganite

We present results of local spin density approximation pseudopotential calculations for the ferroelectromagnet, yttrium manganite (YMnO3). The origin of the differences between ferroelectric and non-ferroelectric perovskite manganites is determined by comparing the calculated properties of yttrium manganite in its ferroelectric hexagonal and non-ferroelectric orthorhombic phases. In addition, orthorhombic YMnO3 is compared with the prototypical non-ferroelectric manganite, lanthanum manganite. We show that, while the octahedral crystal field splitting of the cubic perovskite structure causes a centro-symmetric Jahn-Teller distortion around the Mn3+ ion, the markedly different splitting in hexagonal perovskites creates an electronic configuration consistent with ferroelectric distortion. We explain the nature of the distortion, and show that a local magnetic moment on the Mn3+ ion is a requirement for it to occur.Comment: Replacement of earlier version with error in pseudopotentia

Robust automated servicing of passenger train fluids

To meet increased capacity demands of passengers in the rail industry, a robotic and autonomous system that services the fluids on passenger rail vehicles was proposed. A hierarchical task analysis of fluid servicing processes was conducted and human and system errors were highlighted. This information, along with opinions of technical managers and staff were inputted into a quality function deployment matrix to make a design specification; from this specification two concepts were proposed. Both concepts are viable but modification to rail vehicles is required. A proof of concept will next be developed to begin a path to a commercial product.Brunel University London would like to acknowledge RSSB and RRUKA for funding this project and providing contact with key rail stakeholders

Room temperature plasmon laser by total internal reflection

Plasmon lasers create and sustain intense and coherent optical fields below light's diffraction limit with the unique ability to drastically enhance light-matter interactions bringing fundamentally new capabilities to bio-sensing, data storage, photolithography and optical communications. However, these important applications require room temperature operation, which remains a major hurdle. Here, we report a room temperature semiconductor plasmon laser with both strong cavity feedback and optical confinement to 1/20th of the wavelength. The strong feedback arises from total internal reflection of surface plasmons, while the confinement enhances the spontaneous emission rate by up to 20 times.Comment: 8 Page, 2 Figure

Probing the ultimate limits of plasmonic enhancement.

Metals support surface plasmons at optical wavelengths and have the ability to localize light to subwavelength regions. The field enhancements that occur in these regions set the ultimate limitations on a wide range of nonlinear and quantum optical phenomena. We found that the dominant limiting factor is not the resistive loss of the metal, but rather the intrinsic nonlocality of its dielectric response. A semiclassical model of the electronic response of a metal places strict bounds on the ultimate field enhancement. To demonstrate the accuracy of this model, we studied optical scattering from gold nanoparticles spaced a few angstroms from a gold film. The bounds derived from the models and experiments impose limitations on all nanophotonic systems.Supported by Air Force Office of Scientific Research grant FA9550-09-1-0562 and by the Army Research Office through Multidisciplinary University Research Initiative grant W911NF-09-1-0539. Also supported by the Leverhulme Trust and the Marie Curie Actions (J.B.P., S.A.M., and A.I.F.-D.), NIH grant R21EB009862 (A.C.), and NIH F32 award F32EB009299 (R.T.H.)

Understanding the direct and indirect mechanisms of xylanase action on starch digestion in broilers

The objective of the current study was to investigate the mechanisms of xylanase action in a maize-soya diet and its effect on starch digestion. A total of 60 broilers were divided into 6 treatment groups; a control group without xylanase, and five other groups supplemented with xylanase (Econase XT 25; 100 g/t) from 1, 2, 3, 4 or 5 weeks before slaughter. At the end of the experiment, digesta was collected from the gizzard, upper and lower small intestine, and both caeca. Digesta pH ranged from pH 2.2-4.4, 5.9-6.6, 6.7-7.8 and 5.7-7.3 in the gizzard, upper small intestine, lower small intestine, and both caeca, respectively, with no effect of xylanase (P > 0.05). Scanning Electron Microscope (SEM) images along with total starch measurements showed the progression of starch digestion through the tract. The SEM did not show any greater disruption to cell wall material with xylanase supplementation. This suggests that xylanase was not working directly on the cell wall and provides evidence for the hypothesis that xylanase works through an indirect mechanism. Peptide YY (PYY) concentration in the blood was higher during the first few weeks of supplementation, with longer periods of supplementation nulling this effect, implying that xylanase may be acting through a prebiotic mechanism. The RT-q PCR results revealed a numerical increase in glucose transporter (GLUT2 and SGLT1) expression at 2 and 3 weeks of xylanase supplementation, respectively, which might suggest a greater absorption capacity of birds. From these results, a potential mechanism of xylanase action in maize-based diets has been proposed

Investigating the association between obesity and asthma in 6- to 8-year-old Saudi children:a matched case-control study

Background: Previous studies have demonstrated an association between obesity and asthma, but there remains considerable uncertainty about whether this reflects an underlying causal relationship. Aims: To investigate the association between obesity and asthma in pre-pubertal children and to investigate the roles of airway obstruction and atopy as possible causal mechanisms. Methods: We conducted an age- and sex-matched case–control study of 1,264 6- to 8-year-old schoolchildren with and without asthma recruited from 37 randomly selected schools in Madinah, Saudi Arabia. The body mass index (BMI), waist circumference and skin fold thickness of the 632 children with asthma were compared with those of the 632 control children without asthma. Associations between obesity and asthma, adjusted for other potential risk factors, were assessed separately in boys and girls using conditional logistic regression analysis. The possible mediating roles of atopy and airway obstruction were studied by investigating the impact of incorporating data on sensitisation to common aeroallergens and measurements of lung function. Results: BMI was associated with asthma in boys (odds ratio (OR)=1.14, 95% confidence interval (CI), 1.08–1.20; adjusted OR=1.11, 95% CI, 1.03–1.19) and girls (OR=1.37, 95% CI, 1.26–1.50; adjusted OR=1.38, 95% CI, 1.23–1.56). Adjusting for forced expiratory volume in 1 s had a negligible impact on these associations, but these were attenuated following adjustment for allergic sensitisation, particularly in girls (girls: OR=1.25; 95% CI, 0.96–1.60; boys: OR=1.09, 95% CI, 0.99–1.19). Conclusions: BMI is associated with asthma in pre-pubertal Saudi boys and girls; this effect does not appear to be mediated through respiratory obstruction, but in girls this may at least partially be mediated through increased risk of allergic sensitisation

Bacterial porin disrupts mitochondrial membrane potential and sensitizes host cells to apoptosis

The bacterial PorB porin, an ATP-binding beta-barrel protein of pathogenic Neisseria gonorrhoeae, triggers host cell apoptosis by an unknown mechanism. PorB is targeted to and imported by host cell mitochondria, causing the breakdown of the mitochondrial membrane potential (delta psi m). Here, we show that PorB induces the condensation of the mitochondrial matrix and the loss of cristae structures, sensitizing cells to the induction of apoptosis via signaling pathways activated by BH3-only proteins. PorB is imported into mitochondria through the general translocase TOM but, unexpectedly, is not recognized by the SAM sorting machinery, usually required for the assembly of beta-barrel proteins in the mitochondrial outer membrane. PorB integrates into the mitochondrial inner membrane, leading to the breakdown of delta psi m. The PorB channel is regulated by nucleotides and an isogenic PorB mutant defective in ATP-binding failed to induce delta psi m loss and apoptosis, demonstrating that dissipation of delta psi m is a requirement for cell death caused by neisserial infection

Living on the edge: utilising lidar data to assess the importance of vegetation structure for avian diversity in fragmented woodlands and their edges

Context: In agricultural landscapes, small woodland patches can be important wildlife refuges. Their value in maintaining biodiversity may, however, be compromised by isolation, and so knowledge about the role of habitat structure is vital to understand the drivers of diversity. This study examined how avian diversity and abundance were related to habitat structure in four small woods in an agricultural landscape in eastern England. Objectives: The aims were to examine the edge effect on bird diversity and abundance, and the contributory role of vegetation structure. Specifically: what is the role of vegetation structure on edge effects, and which edge structures support the greatest bird diversity? Methods: Annual breeding bird census data for 28 species were combined with airborne lidar data in linear mixed models fitted separately at (i) the whole wood level, and (ii) for the woodland edges only. Results: Despite relatively small woodland areas (4.9–9.4 ha), bird diversity increased significantly towards the edges, being driven in part by vegetation structure. At the whole woods level, diversity was positively associated with increased vegetation above 0.5 m and especially with increasing vegetation density in the understorey layer, which was more abundant at the woodland edges. Diversity along the edges was largely driven by the density of vegetation below 4 m. Conclusions: The results demonstrate that bird diversity was maximised by a diverse vegetation structure across the wood and especially a dense understorey along the edge. These findings can assist bird conservation by guiding habitat management of remaining woodland patches

Projections of the healthcare costs and disease burden due to hepatitis C infection under different treatment policies in Malaysia, 2018-2040

The World Health Organisation (WHO) has set ambitious goals to reduce the global disease burden associated with, and eventually eliminate, viral hepatitis

Increasing condom use in heterosexual men: development of a theory-based interactive digital intervention

Increasing condom use to prevent sexually transmitted infections is a key public health goal. Interventions are more likely to be effective if they are theory- and evidence-based. The Behaviour Change Wheel (BCW) provides a framework for intervention development. To provide an example of how the BCW was used to develop an intervention to increase condom use in heterosexual men (the MenSS website), the steps of the BCW intervention development process were followed, incorporating evidence from the research literature and views of experts and the target population. Capability (e.g. knowledge) and motivation (e.g. beliefs about pleasure) were identified as important targets of the intervention. We devised ways to address each intervention target, including selecting interactive features and behaviour change techniques. The BCW provides a useful framework for integrating sources of evidence to inform intervention content and deciding which influences on behaviour to target