Excitonic ferromagnetism in the hexaborides

A ferromagnet with a small spontaneous moment but with a high Curie temperature can be obtained by doping an excitonic insulator made from a spin triplet exciton condensate. Such a condensate can occur in a semimetal with a small overlap or a semiconductor with a small bandgap. We propose that it is responsible for the unexpected ferromagnetism in the doped hexaboride material Ca_{1-x}La_xB_6.Comment: 4 pages, 3 figure

Succession of biofilm communities responsible for biofouling of membrane bioreactors (MBRs)

© 2017 Luo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Biofilm formation is one of the main factors associated with membrane biofouling in membrane bioreactors (MBRs). As such, it is important to identify the responsible organisms to develop targeted strategies to control biofouling. This study investigated the composition and changes in the microbial communities fouling MBR membranes over time and correlated those changes with an increase in transmembrane pressure (TMP). Based on qPCR data, bacteria were the dominant taxa of the biofilm (92.9–98.4%) relative to fungi (1.5–6.9%) and archaea (0.03–0.07%). NMDS analysis indicated that during the initial stages of operation, the biofilm communities were indistinguishable from those found in the sludge. However, the biofilm community significantly diverged from the sludge over time and ultimately showed a unique biofilm profile. This suggested that there was strong selection for a group of organisms that were biofilm specialists. This pattern of succession and selection was correlated with the rapid increase in TMP, where bacteria including Rhodospirillales, Sphingomonadales and Rhizobiales dominated the biofilm at this time. While most of the identified fungal OTUs matched Candida sp., the majority of fungal communities were unclassified by 18S rRNA gene sequencing. Collectively, the data suggests that bacteria, primarily, along with fungi may play an important role in the rapid TMP increase and loss of system performance

Polarization and temperature dependence of photoluminescence from zincblende and wurtzite InP nanowires

We use polarization-resolved and temperature-dependent photoluminescence of single zincblende (ZB) (cubic) and wurtzite (WZ) (hexagonal) InPnanowires to probe differences in selection rules and bandgaps between these two semiconductor nanostructures. The WZ nanowires exhibit a bandgap80meV higher in energy than the ZB nanowires. The temperature dependence of the PL is similar but not identical for the WZ and ZB nanowires. We find that ZB nanowires exhibit strong polarization parallel to the nanowire axis, while the WZ nanowires exhibit polarized emission perpendicular to the nanowire axis. This behavior is interpreted in terms of the different selection rules for WZ and ZB crystal structures.A.M., L.V.T., T.B.H., H.E.J., L.M.S., and J.M.Y.-R. acknowledge support from the Institute for Nanoscale Science and Technology of the University of Cincinnati and the National Science Foundation through Grant Nos. EEC/NUE 0532495 and ECCS 0701703. The Australian authors acknowledge support from the Australian Research Council. Y.K. acknowledges support by the Korean Science and Engineering Foundation KOSEF through Grant No. F01- 2007-000-10087-0

Water splitting with polyoxometalate-treated photoanodes: Enhancing performance through sensitizer design

Visible light driven water oxidation has been demonstrated at near-neutral pH using photoanodes based on nanoporous films of TiO2, polyoxometalate (POM) water oxidation catalyst [{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]10- (1), and both known photosensitizer [Ru(bpy)2(H4dpbpy)]2+ (P2) and the novel crown ether functionalized dye [Ru(5-crownphen)2(H2dpbpy)] (H22). Both triads, containing catalyst 1, and catalyst-free dyads, produce O2 with high faradaic efficiencies (80 to 94%), but presence of catalyst enhances quantum yield by up to 190% (maximum 0.39%). New sensitizer H22 absorbs light more strongly than P2, and increases O2 quantum yields by up to 270%. TiO2-2 based photoelectrodes are also more stable to desorption of active species than TiO2-P2: losses of catalyst 1 are halved when pH > TiO2 point-of-zero charge (pzc), and losses of sensitizer reduced below the pzc (no catalyst is lost when pH < pzc). For the triads, quantum yields of O2 are higher at pH 5.8 than at pH 7.2, opposing the trend observed for 1 under homogeneous conditions. This is ascribed to lower stability of the dye oxidized states at higher pH, and less efficient electron transfer to TiO2, and is also consistent with the 4th 1-to-dye electron transfer limiting performance rather than catalyst TOFmax. Transient absorption reveals that TiO2-2-1 has similar 1st electron transfer dynamics to TiO2-P2-1, with rapid (ps timescale) formation of long-lived TiO2(e-)-2-1(h+) charge separated states, and demonstrates that metallation of the crown ether groups (Na+/Mg2+) has little or no effect on electron transfer from 1 to 2. The most widely relevant findings of this study are therefore: (i) increased dye extinction coefficients and binding stability significantly improve performance in dye-sensitized water splitting systems; (ii) binding of POMs to electrode surfaces can be stabilized through use of recognition groups; (iii) the optimal homogeneous and TiO2-bound operating pHs of a catalyst may not be the same; and (iv) dye-sensitized TiO2 can oxidize water without a catalyst

The ‘algebra of evolution’: the Robertson–Price identity and viability selection for body mass in a wild bird population

By the Robertson–Price identity, the change in a quantitative trait owing to selection, is equal to the trait’s covariance with relative fitness. In this study, we applied the identity to long-term data on superb fairy-wrens Malurus cyaneus, to estimate phenotypic and genetic change owing to juvenile viability selection. Mortality in the four-week period between fledging and independence was 40%, and heavier nestlings were more likely to survive, but why? There was additive genetic variance for both nestling mass and survival, and a positive phenotypic covariance between the traits, but no evidence of additive genetic covariance. Comparing standardized gradients, the phenotypic selection gradient was positive, βP = 0.108 (0.036, 0.187 95% CI), whereas the genetic gradient was not different from zero, βA = −0.025 (−0.19, 0.107 95% CI). This suggests that factors other than nestling mass were the cause of variation in survival. In particular, there were temporal correlations between mass and survival both within and between years. We suggest that use of the Price equation to describe cross-generational change in the wild may be challenging, but a more modest aim of estimating its first term, the Robertson–Price identity, to assess within-generation change can provide valuable insights into the processes shaping phenotypic diversity in natural populations. This article is part of the theme issue ‘Fifty years of the Price equation’G.K.H. was supported by the U.K. Natural Environment Research Council (grant no. NE/L002558/1) through the University of Edinburgh’s E3 Doctoral Training Partnership, and L.E.B.K. was funded by an ARC Future Fellowship FT110100453. The long-term superb fairy-wren study research has been facilitated by a series of Discovery Project grants from the Australian Research Council to A.C. and L.E.B.K., most recently DP150100298

The characterisation of microsatellite markers reveals tetraploidy in the Greater Water Parsnip, Sium latifolium (Apiaceae).

BACKGROUND: The Greater Water Parsnip, Sium latifolium (Apiaceae), is a marginal aquatic perennial currently endangered in England and consequently the focus of a number of conservation translocation projects. Microsatellite markers were developed for S. latifolium to facilitate comparison of genetic diversity and composition between natural and introduced populations. RESULTS: We selected 65 S. latifolium microsatellite (MiSeq) sequences and designed primer pairs for these. Primer sets were tested in 32 individuals. We found 15 polymorphic loci that amplified consistently. For the selected 15 loci, the number of alleles per locus ranged from 8 to 17. For all loci, S. latifolium individuals displayed up to four alleles indicating polyploidy in this species. CONCLUSIONS: These are the first microsatellite loci developed for S. latifolium and each individual displayed 1-4 alleles per locus, suggesting polyploidy in this species. These markers provide a valuable resource in evaluating the population genetic composition of this endangered species and thus will be useful for guiding conservation and future translocations of the species

The A-B transition in superfluid helium-3 under confinement in a thin slab geometry

The influence of confinement on the topological phases of superfluid 3He is studied using the torsional pendulum method. We focus on the phase transition between the chiral A-phase and the time-reversal-invariant B-phase, motivated by the prediction of a spatiallymodulated (stripe) phase at the A-B phase boundary. We confine superfluid 3He to a single 1.08 {\mu}m thick nanofluidic cavity incorporated into a high-precision torsion pendulum, and map the phase diagram between 0.1 and 5.6 bar. We observe only small supercooling of the A-phase, in comparison to bulk or when confined in aerogel. This has a non-monotonic pressure dependence, suggesting that a new intrinsic B-phase nucleation mechanism operates under confinement, mediated by the putative stripe phase. Both the phase diagram and the relative superfluid fraction of the A and B phases, show that strong coupling is present at all pressures, with implications for the stability of the stripe phase.Comment: 6 figures, 1 table + supplemental informatio

A new automated method for the determination of the Total Antioxidant Capacity (TAC) of human plasma, based on the crocin bleaching assay

BACKGROUND: Antioxidant molecules, which scavenge free radical species to prevent or delay oxidative damage of important macromolecules, membrane lipids and lipoproteins, are prevalent in plasma and other biological fluids. Among them, bilirubin, uric acid and protein thiols are the major endogenous antioxidants, while vitamins C and E, as well as a number of food-derived (poly)aromatic substances, belonging to stilbens, flavonoids and phenolic acids, are the main classes of nutritional antioxidants. Assays for total antioxidant capacity in plasma differ in their type of oxidation source, target and measurement used to detect the oxidized product. METHODS: In the present work we present an automated assay for the estimation of blood total antioxidant capacity (TAC assay), based on the crocin bleaching (oxidation) method. This method was adapted on a modern autoanalyzer, was linear over a wide range of values (0–3 mmol/L), and performed using an end point measurement. RESULTS: The TAC method presented a linear correlation with another automated commercial Total Antioxidant Status (TAS) test. Detection of the interference of different metabolites revealed a significant participation of TAC from uric acid, bilirubin, albumin, a minor interference from ascorbic acid, and no interference from hemoglobin. TAC was not modified by two freeze/thawing cycles, and was stable in samples stored at room temperature for 4 hours. K-EDTA and heparin were the best anticoagulants, while citrate decreased TAC by 20%. Reference values derived from samples of normal blood donors was 1.175 ± 0.007 mmol/L (mean ± SEM), while a diet rich in antioxidants more than doubled this value. CONCLUSIONS: The proposed TAC assay, is fully automated, stable and reliable, and could be of value in the estimation of the AC of plasma. It is further proposed to calculate the antioxidant capacity of plasma after a subtraction of all interference deriving from endogenous and/or exogenous metabolites. The antioxidant capacity of plasma thus calculated can be used as a useful indicator of the antioxidant value of foods and beverages in the daily diet

Identifying Schistosoma japonicum Excretory/Secretory Proteins and Their Interactions with Host Immune System

Schistosoma japonicum is a major infectious agent of schistosomiasis. It has been reported that large number of proteins excreted and secreted by S. japonicum during its life cycle are important for its infection and survival in definitive hosts. These proteins can be used as ideal candidates for vaccines or drug targets. In this work, we analyzed the protein sequences of S. japonicum and found that compared with other proteins in S. japonicum, excretory/secretory (ES) proteins are generally longer, more likely to be stable and enzyme, more likely to contain immune-related binding peptides and more likely to be involved in regulation and metabolism processes. Based on the sequence difference between ES and non-ES proteins, we trained a support vector machine (SVM) with much higher accuracy than existing approaches. Using this SVM, we identified 191 new ES proteins in S. japonicum, and further predicted 7 potential interactions between these ES proteins and human immune proteins. Our results are useful to understand the pathogenesis of schistosomiasis and can serve as a new resource for vaccine or drug targets discovery for anti-schistosome

CD74 in kidney disease

CD74 (invariant MHC class II) regulates protein trafficking and is a receptor for macrophage migration inhibitory factor (MIF) and d-dopachrome tautomerase (d-DT/MIF-2). CD74 expression is increased in tubular cells and/or glomerular podocytes and parietal cells in human metabolic nephropathies, polycystic kidney disease, graft rejection and kidney cancer and in experimental diabetic nephropathy and glomerulonephritis. Stressors like abnormal metabolite (glucose, lyso-Gb3) levels and inflammatory cytokines increase kidney cell CD74. MIF activates CD74 to increase inflammatory cytokines in podocytes and tubular cells and proliferation in glomerular parietal epithelial cells and cyst cells. MIF overexpression promotes while MIF targeting protects from experimental glomerular injury and kidney cysts, and interference with MIF/CD74 signaling or CD74 deficiency protected from crescentic glomerulonephritis. However, CD74 may protect from interstitial kidney fibrosis. Furthermore, CD74 expression by stressed kidney cells raises questions about the kidney safety of cancer therapy strategies delivering lethal immunoconjugates to CD74-expressing cells. Thus, understanding CD74 biology in kidney cells is relevant for kidney therapeuticsGrant support: ISCIII and FEDER funds CP14/00133, PI13/00047, Sociedad Española de Nefrologia, ISCIII-RETIC REDinREN/RD012/0021, Comunidad de Madrid CIFRA S2010/ BMD-2378. Salary support: FIS to LV-R, Miguel Servet to MS-N. Programa Intensificación Actividad Investigadora (ISCIII/ Agencia Laín-Entralgo/CM) to AO