Doped two orbital chains with strong Hund's rule couplings - ferromagnetism, spin gap, singlet and triplet pairings

Different models for doping of two-orbital chains with mobile $S=1/2$ fermions and strong, ferromagnetic (FM) Hund's rule couplings stabilizing the S=1 spins are investigated by density matrix renormalization group (DMRG) methods. The competition between antiferromagnetic (AF) and FM order leads to a rich phase diagram with a narrow FM region for weak AF couplings and strongly enhanced triplet pairing correlations. Without a level difference between the orbitals, the spin gap persists upon doping, whereas gapless spin excitations are generated by interactions among itinerant polarons in the presence of a level difference. In the charge sector we find dominant singlet pairing correlations without a level difference, whereas upon the inclusion of a Coulomb repulsion between the orbitals or with a level difference, charge density wave (CDW) correlations decay slowest. The string correlation functions remain finite upon doping for all models.Comment: 9pages, 9figure

Exposure to aircraft and road traffic noise and associations with heart disease and stroke in six European countries: a cross-sectional study

This work was supported by the Economic and Social Research Council (grant ES/F038763/1) with additional funding from the European Network for Noise and Health (ENNAH, EU FP7 grant number 226442)

Degradation of millimolar concentration of the herbicide dalapon (2,2-Dichloropropionic Acid) by rhizobium Sp isolated from soil

The herbicide Dalapon is widely used in agricultural areas and is persistent in ground water. A Rhizobium sp. was able to grow at 0.2 mM 2,2-dichloropropionic acid (2,2DCP), which was 100-fold lower than the concentration of the substrate routinely used. Apparently, no new dehalogenases are required to allow growth on this low concentration of 2,2DCP as judged by electrophoretic mobility of dehalogenase proteins in native-PAGE analysis and protein separation by anion-exchange column chromatography. The kinetic analysis suggested that the known dehalogenases were able to act efficiently on low concentrations of haloalkanoic acids. The amount of each dehalogenase, from cells grown on low substrate concentration was different compared to that seen at 20 mM 2,2DCP due to complex regulatory controls, which respond to the growth environment

CD32+CD4+ T cells are enriched in HIV-1 DNA

Background: CD32 was reported to mark the HIV-1 reservoir harboring replication-competentproviruses, but several recent reports challenged this finding. We aimed to confirm or deny theusefulness of CD32 as a marker of the latent reservoir and to further characterize the phenotype of theseCD32+CD4+ T cells, as well as the transcriptional activity of HIV-1 residing in this reservoir.Methods: CD32 expression was measured by flow cytometry on PBMCs from ART-treated HIV-1 infectedpatients and uninfected controls. Co-expression of HLA-DR, immune checkpoint receptors (PD-1, TIGIT,LAG-3) and CD2 was measured by flow cytometry. HIV-1 DNA and unspliced RNA were quantified in bulkPBMC samples and in CD32+ and CD32- fractions of CD4+ T cells sorted with magnetic beads.Results: The median frequency of CD32+CD4+ T cells in HIV-infected individuals (n=18) was 0.07% whichwas significantly higher than in the controls (0.01%, p=0.016). We found a positive correlation betweenthe percentage of CD32+CD4+ T cells and total HIV-1 DNA load in PBMCs (rho=0.58; p=0.012).CD32+CD4+ T cells demonstrated increased expression of LAG-3 (p=0.016), TIGIT (p=0.016) and HLA-DR(p< 0.0001) compared with CD32-CD4+ T cells in HIV-infected patients. In the full sample, CD32+CD4+ Tcells were not enriched for HIV-1 DNA or RNA compared with CD32-CD4+ cells. However, in a subgroupof patients with smaller (and presumably purer) CD32+CD4+ T-cell fractions (n=9), we observed asignificant enrichment for HIV-1 DNA in this fraction (average of 6-fold, p=0.012). We thereforeoptimized our assay to isolate a purer fraction of CD32+CD4+ T cells and found a positive enrichment forHIV-1 DNA in the CD32+CD4+ fraction in all the additional patients (n=7) tested (average of 14-fold,p=0.016).Conclusions: We confirmed that CD32+CD4+ T cells are enriched for HIV-1 DNA, although the level ofenrichment was less pronounced than previously reported. Our results also highlight the importance ofgetting a sufficiently pure CD32+CD4+ T cells fraction for analysis and might explain the negative resultsobtained by others. Our data further indicate that these CD32+CD4+ T cells are activated cells, and thatthey often co-express the immune checkpoint receptors TIGIT and LAG-3.info:eu-repo/semantics/publishe

Soil seed banks in the floodplain of a large river: A test of hypotheses on seed bank composition in relation to flooding and established vegetation

International audienceQuestions This study investigates soil seed banks in relation to established vegetation in the floodplain of a large river with high‐energy floods. It addresses the composition of seed banks and extant vegetation over a wide flooding and succession gradient. Tested hypotheses were: (a) species richness and seed bank density are highest in mid‐succession habitats; (b) seed bank variability increases with succession; (c) the proportion of species in the established vegetation with permanent seed banks declines with succession; and (d) similarity between vegetation and seed bank declines with succession. Location Mareau‐aux‐Prés, the Loire River, close to Orléans, France. Methods Seed banks and vegetation were sampled in five habitats from a succession series: (a) Pioneer vegetation of shores and sandbanks; (b) softwood shrubs; (c) softwood forest; (d) mature forest; and (e) Elytrigia‐dominated grasslands. Sample units were 5 m x 5 m plots. Soil samples were taken from the upper 6 cm. Seed banks were studied via the seedling emergence method, followed by screening of sediment for remaining seeds. Composition of seed banks was compared to that of vegetation using the Sørenson similarity index. Results Seed bank density varied between 260 and 11,260 seeds/m2. Clear differences between habitats existed in the composition of species in seed banks and established vegetation. Seeds of most dominant species were distributed across the whole range of floodplain habitats but species were more restricted in the vegetation. Species richness and seed bank densities did not vary with succession as expected, but the proportion of species that produce persistent seed banks did decline with succession. Conclusions Floodplains of large rivers provide an excellent context to test hypotheses about the processes that influence the links between seed banks and standing vegetation. In the case of high‐energy floods and high sediment dynamics, the methods commonly used to study seed banks can, however, be questioned