The Effect of Splayed Pins on Vortex Creep and Critical Currents

We study the effects of splayed columnar pins on the vortex motion using realistic London Langevin simulations. At low currents vortex creep is strongly suppressed, whereas the critical current j_c is enhanced only moderately. Splaying the pins generates an increasing energy barrier against vortex hopping, and leads to the forced entanglement of vortices, both of which suppress creep efficiently. On the other hand splaying enhances kink nucleation and introduces intersecting pins, which cut off the energy barriers. Thus the j_c enhancement is strongly parameter sensitive. We also characterize the angle dependence of j_c, and the effect of different splaying geometries.Comment: 4 figure

Caenorhabditis elegans Semi-Automated Liquid Screen Reveals a Specialized Role for the Chemotaxis Gene cheB2 in Pseudomonas aeruginosa Virulence

Pseudomonas aeruginosa is an opportunistic human pathogen that causes infections in a variety of animal and plant hosts. Caenorhabditis elegans is a simple model with which one can identify bacterial virulence genes. Previous studies with C. elegans have shown that depending on the growth medium, P. aeruginosa provokes different pathologies: slow or fast killing, lethal paralysis and red death. In this study, we developed a high-throughput semi-automated liquid-based assay such that an entire genome can readily be scanned for virulence genes in a short time period. We screened a 2,200-member STM mutant library generated in a cystic fibrosis airway P. aeruginosa isolate, TBCF10839. Twelve mutants were isolated each showing at least 70% attenuation in C. elegans killing. The selected mutants had insertions in regulatory genes, such as a histidine kinase sensor of two-component systems and a member of the AraC family, or in genes involved in adherence or chemotaxis. One mutant had an insertion in a cheB gene homologue, encoding a methylesterase involved in chemotaxis (CheB2). The cheB2 mutant was tested in a murine lung infection model and found to have a highly attenuated virulence. The cheB2 gene is part of the chemotactic gene cluster II, which was shown to be required for an optimal mobility in vitro. In P. aeruginosa, the main player in chemotaxis and mobility is the chemotactic gene cluster I, including cheB1. We show that, in contrast to the cheB2 mutant, a cheB1 mutant is not attenuated for virulence in C. elegans whereas in vitro motility and chemotaxis are severely impaired. We conclude that the virulence defect of the cheB2 mutant is not linked with a global motility defect but that instead the cheB2 gene is involved in a specific chemotactic response, which takes place during infection and is required for P. aeruginosa pathogenicity

Anomalous behavior of the irreversible magnetization and time relaxation in YBa2_2Cu3_3O7_7 single crystals with splayed tracks

We have studied the angular dependence of the irreversible magnetization and its time relaxation in YBa$_2$Cu$_3$O$_7$ single crystals with one or two families of columnar defects inclined with respect to the c-axis. At high magnetic fields, the magnetization shows the usual maximum centered at the mean tracks' orientation and an associated minimum in the normalized relaxation rate. In contrast, at low fields we observe an anomalous local minimum in the magnetization and a maximum in the relaxation rate. We present a model to explain this anomaly based on the slowing down of the creep processes arising from the increase of the vortex-vortex interactions as the applied field is tilted away from the mean tracks' direction.Comment: 15 pages, 6 figures. Submitted to Phys. Rev .

Tomato Pathogenesis-related Protein Genes are Expressed in Response to Trialeurodes vaporariorum and Bemisia tabaci Biotype B Feeding

The temporal and spatial expression of tomato wound- and defense-response genes to Bemisia tabaci biotype B (the silverleaf whitefly) and Trialeurodes vaporariorum (the greenhouse whitefly) feeding were characterized. Both species of whiteflies evoked similar changes in tomato gene expression. The levels of RNAs for the methyl jasmonic acid (MeJA)- or ethylene-regulated genes that encode the basic β-1,3-glucanase (GluB), basic chitinase (Chi9), and Pathogenesis-related protein-1 (PR-1) were monitored. GluB and Chi9 RNAs were abundant in infested leaves from the time nymphs initiated feeding (day 5). In addition, GluB RNAs accumulated in apical non-infested leaves. PR-1 RNAs also accumulated after whitefly feeding. In contrast, the ethylene- and salicylic acid (SA)-regulated Chi3 and PR-4 genes had RNAs that accumulated at low levels and GluAC RNAs that were undetectable in whitefly-infested tomato leaves. The changes in Phenylalanine ammonia lyase5 (PAL5) were variable; in some, but not all infestations, PAL5 RNAs increased in response to whitefly feeding. PAL5 RNA levels increased in response to MeJA, ethylene, and abscisic acid, and declined in response to SA. Transcripts from the wound-response genes, leucine aminopeptidase (LapA1) and proteinase inhibitor 2 (pin2), were not detected following whitefly feeding. Furthermore, whitefly infestation of transgenic LapA1:GUS tomato plants showed that whitefly feeding did not activate the LapA1 promoter, although crushing of the leaf lamina increased GUS activity up to 40 fold. These studies indicate that tomato plants perceive B. tabaci and T. vaporariorum in a manner similar to baterical pathogens and distinct from tissue-damaging insects

Surviving Sepsis Campaign: International guidelines for management of severe sepsis and septic shock: 2008

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Track D Social Science, Human Rights and Political Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd

The Interplay between Glucose-Regulated Protein 78 (GRP78) and Steroids in the Reproductive System

The glucose-regulated protein 78 (GRP78) is a molecular chaperone that is responsible for protein folding, which belongs to the heat shock protein 70 kDa (HSPA/HSP70). Because of the conjunction of GRP78 transcription with endoplasmic reticulum stress, the chaperone plays an important role in the unfolded protein response (UPR), which is induced after the accumulation of misfolded proteins. In the last years, a significant body of research concentrated on interplay between GRP78 and sexual steroid hormones. Throughout this review, we describe the mechanisms by which GRP78 regulates steroidogenesis at multiple levels and how steroids modulate GRP78 expression in different mammalian reproductive organs. Finally, we discuss the cooperation between GRP78 and steroids for cell survival and proliferation in the context of reproduction and tumorigenesis. This new paradigm offers significant opportunities for future exploration