2,466 research outputs found
IsaB Inhibits Autophagic Flux to Promote Host Transmission of Methicillin-Resistant Staphylococcus aureus.
Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major nosocomial pathogen that is widespread in both health-care facilities and in the community at large, as a result of direct host-to-host transmission. Several virulence factors are associated with pathogen transmission to naive hosts. Immunodominant surface antigen B (IsaB) is a virulence factor that helps Staphylococcus aureus to evade the host defense system. However, the mechanism of IsaB on host transmissibility remains unclear. We found that IsaB expression was elevated in transmissible MRSA. Wild-type isaB strains inhibited autophagic flux to promote bacterial survival and elicit inflammation in THP-1 cells and mouse skin. MRSA isolates with increased IsaB expression showed decreased autophagic flux, and the MRSA isolate with the lowest IsaB expression showed increased autophagic flux. In addition, recombinant IsaB rescued the virulence of the isaB deletion strain and increased the group A streptococcus (GAS) virulence in vivo. Together, these results reveal that IsaB diminishes autophagic flux, thereby allowing MRSA to evade host degradation. These findings suggest that IsaB is a suitable target for preventing or treating MRSA infection
Integral equation method for the electromagnetic wave propagation in stratified anisotropic dielectric-magnetic materials
We investigate the propagation of electromagnetic waves in stratified
anisotropic dielectric-magnetic materials using the integral equation method
(IEM). Based on the superposition principle, we use Hertz vector formulations
of radiated fields to study the interaction of wave with matter. We derive in a
new way the dispersion relation, Snell's law and reflection/transmission
coefficients by self-consistent analyses. Moreover, we find two new forms of
the generalized extinction theorem. Applying the IEM, we investigate the wave
propagation through a slab and disclose the underlying physics which are
further verified by numerical simulations. The results lead to a unified
framework of the IEM for the propagation of wave incident either from a medium
or vacuum in stratified dielectric-magnetic materials.Comment: 14pages, 3figure
The Sac1 Lipid Phosphatase Regulates Cell Shape Change and the JNK Cascade during Dorsal Closure in Drosophila
AbstractThe Sac1 lipid phosphatase dephosphorylates several phosphatidylinositol (PtdIns) phosphates and, in yeast, regulates a diverse range of cellular processes including organization of the actin cytoskeleton and secretion [1]. We have identified mutations in the gene encoding Drosophila Sac1. sac1 mutants die as embryos with defects in dorsal closure (DC). DC involves the migration of the epidermis to close a hole in the dorsal surface of the embryo occupied by the amnioserosa. It requires cell shape change in both the epidermis and amnioserosa and activation of a Jun N-terminal kinase (JNK) MAPK cascade in the leading edge cells of the epidermis [2]. Loss of Sac1 leads to the improper activation of two key events in DC: cell shape change in the amnioserosa and JNK signaling. sac1 interacts genetically with other participants in these two events, and our data suggest that loss of Sac1 leads to upregulation of one or more signals controlling DC. This study is the first report of a role for Sac1 in the development of a multicellular organism
Efficacy of multidomain interventions to improve physical frailty, depression and cognition: data from cluster- randomized controlled trials
BackgroundFrailty is the pre- eminent exigency of aging. Although frailty- related impairments are preventable, and multidomain interventions appear more effective than unimodal ones, the optimal components remain uncertain.MethodsWe devised multidomain interventions against physical and cognitive decline among prefrail/frail community- dwelling - ¥65- year- olds and evaluated these in complementary cluster- randomized trials of efficacy and participant empowerment. The Efficacy Study compared ~3- monthly telephone consultations vs. 16, 2 h sessions/year comprising communally partaken physical and cognitive training plus nutrition and disease education; the Empowerment Study compared the standard Efficacy Study multidomain intervention (Sessions 1- 10) vs. an enhanced version redesigned to empower and motivate individual participants. Changes from baseline in physical, functional, and cognitive performance were measured after 6 and 12 months in the Efficacy Study and after 6 months in the Empowerment Study, with post- intervention follow- up at 9 months. Primary outcomes are as follows: Cardiovascular Health Study frailty score; gait speed; handgrip strength; and Montreal Cognitive Assessment (MoCA). Secondary outcomes are as follows: instrumental activities of daily living; metabolic equivalent of task (MET); depressed mood (Geriatric Depression Scale- 5 - ¥2); and malnutrition (Mini- Nutritional Assessment short- form - ¤11). Intervention effects were analyzed using a generalized linear mixed model.ResultsEfficacy Study participants (n = 1082, 40 clusters) were 75.1 ± 6.3 years old, 68.7% women, and 64.7% prefrail/frail; analytic clusters: 19 intervention (410/549 completed) vs. 21 control (375/533 completed). Empowerment Study participants (n = 440, 14 clusters) were 75.9 ± 7.1 years old, 83.6% women, and 56.7% prefrail/frail; analytic clusters: seven intervention (209/230 completed) vs. seven control (189/210 completed). The standard and enhanced multidomain interventions both reduced frailty and significantly improved aspects of physical, functional, and cognitive performance, especially among - ¥75- year- olds. Standard multidomain intervention decreased depression [odds ratio 0.56, 95% confidence interval (CI) 0.32, 0.99] and malnutrition (odds ratio 0.45, 95% CI 0.26, 0.78) by 12 months and improved concentration at Months 6 (0.23, 95% CI 0.04, 0.42) and 12 (0.46, 95% CI 0.22, 0.70). Participant empowerment augmented activity (4.67 MET/h, 95% CI 1.64, 7.69) and gait speed (0.06 m/s, 95% CI 0.00, 0.11) at 6 months, with sustained improvements in delayed recall (0.63, 95% CI 0.20, 1.06) and MoCA performance (1.29, 95% CI 0.54, 2.03), and less prevalent malnutrition (odds ratio 0.39, 95% CI 0.18, 0.84), 3 months after the intervention ceased.ConclusionsPragmatic multidomain intervention can diminish physical frailty, malnutrition, and depression and enhance cognitive performance among community- dwelling elders, especially - ¥75- year- olds; this might supplement healthy aging policies, probably more effectively if participants are empowered.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/156002/1/jcsm12534.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/156002/2/10.1002_jcsm.12534_Fig_S4.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/156002/3/jcsm12534_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/156002/4/10.1002_jcsm.12534_Fig_S2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/156002/5/10.1002_jcsm.12534_Table_S3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/156002/6/10.1002_jcsm.12534_Fig_S3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/156002/7/10.1002_jcsm.12534_Appendix_S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/156002/8/10.1002_jcsm.12534_Table_S2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/156002/9/10.1002_jcsm.12534_Table_S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/156002/10/10.1002_jcsm.12534_Fig_S1.pd
Feasibility of Direct Utilization of Biomass Gasification Product Gas Fuels in Tubular Solid Oxide Fuel Cells for On-Site Electricity Generation
Biomass is one of the most abundant and cheap renewable energy sources, and gasification product gases from the pyrolysis process of biomass, such as mallee wood and wheat straw, contain typically 20-27% H2 and a small amount of CO and CH4 (8-13%). Here, preliminary results on the performance of Ni/Y2O3-ZrO2 cermet anode-supported tubular solid oxide fuel cells (SOFCs) for the electricity generation from gasification product gases are presented. Two product gases derived from mallee wood and wheat straw are used as the fuels. The tubular SOFCs deliver a maximum power density over 576 mW cm-2 at 800 °C, close to the power density based on the equivalent amount of pure H2 or CH4 fuel. The power density is affected by the flow rate of product gas, but there are no significant differences of power output among the product gas sources used. However, the cell performance decreases gradually, and the degradation in the electricity generation performance of the tubular SOFC is most likely due to the presence of impurities, such as sulfur- and chlorine-containing compounds in the biomass feedstock. The results demonstrate the feasibility of the gasification product gas-fueled SOFCs for the on-site electricity generation, and the deterioration effect of impurities could be mitigated by cleaning the product gases or developing the contaminant-tolerant electrodes
Phenomenological Consequences of Right-handed Down Squark Mixings
The mixings of quarks, hidden from view in Standard Model (SM), are
naturally the largest if one has an Abelian flavor symmetry. With supersymmetry
(SUSY) their effects can surface via squark loops. Squark and
gluino masses are at TeV scale, but they can still induce effects comparable to
SM in (or ) mixings, while mixing could be close to recent
hints from data. In general, CP phases would be different from SM, as may be
indicated by recent B Factory data. Presence of non-standard soft SUSY
breakings with large could enhance (or )
transitions.Comment: Version to appear in Phys. Rev. Let
Isostructural Phase Transition of TiN Under High Pressure
In situ high-pressure energy dispersive x-ray diffraction experiments on
polycrystalline powder TiN with NaCl-type structure have been conducted with
the pressure up to 30.1 GPa by using the diamond anvil cell instrument with
synchrotron radiation at room tempearture. The experimental results suggested
that an isostructural phase transition might exist at about 7 GPa as revealed
by the discontinuity of V/V0 with pressure.Comment: submitte
New Family of Robust 2D Topological Insulators in van der Waals Heterostructures
We predict a new family of robust two-dimensional (2D) topological insulators
in van der Waals heterostructures comprising graphene and chalcogenides BiTeX
(X=Cl, Br and I). The layered structures of both constituent materials produce
a naturally smooth interface that is conducive to proximity induced new
topological states. First principles calculations reveal intrinsic
topologically nontrivial bulk energy gaps as large as 70-80 meV, which can be
further enhanced up to 120 meV by compression. The strong spin-orbit coupling
in BiTeX has a significant influence on the graphene Dirac states, resulting in
the topologically nontrivial band structure, which is confirmed by calculated
nontrivial Z2 index and an explicit demonstration of metallic edge states. Such
heterostructures offer an unique Dirac transport system that combines the 2D
Dirac states from graphene and 1D Dirac edge states from the topological
insulator, and it offers new ideas for innovative device designs
Multiplex immunofluorescence to measure dynamic changes in tumor-infiltrating lymphocytes and PD-L1 in early-stage breast cancer.
BACKGROUND: The H&E stromal tumor-infiltrating lymphocyte (sTIL) score and programmed death ligand 1 (PD-L1) SP142 immunohistochemistry assay are prognostic and predictive in early-stage breast cancer, but are operator-dependent and may have insufficient precision to characterize dynamic changes in sTILs/PD-L1 in the context of clinical research. We illustrate how multiplex immunofluorescence (mIF) combined with statistical modeling can be used to precisely estimate dynamic changes in sTIL score, PD-L1 expression, and other immune variables from a single paraffin-embedded slide, thus enabling comprehensive characterization of activity of novel immunotherapy agents.
METHODS: Serial tissue was obtained from a recent clinical trial evaluating loco-regional cytokine delivery as a strategy to promote immune cell infiltration and activation in breast tumors. Pre-treatment biopsies and post-treatment tumor resections were analyzed by mIF (PerkinElmer Vectra) using an antibody panel that characterized tumor cells (cytokeratin-positive), immune cells (CD3, CD8, CD163, FoxP3), and PD-L1 expression. mIF estimates of sTIL score and PD-L1 expression were compared to the H&E/SP142 clinical assays. Hierarchical linear modeling was utilized to compare pre- and post-treatment immune cell expression, account for correlation of time-dependent measurement, variation across high-powered magnification views within each subject, and variation between subjects. Simulation methods (Monte Carlo, bootstrapping) were used to evaluate the impact of model and tissue sample size on statistical power.
RESULTS: mIF estimates of sTIL and PD-L1 expression were strongly correlated with their respective clinical assays (p \u3c .001). Hierarchical linear modeling resulted in more precise estimates of treatment-related increases in sTIL, PD-L1, and other metrics such as CD8+ tumor nest infiltration. Statistical precision was dependent on adequate tissue sampling, with at least 15 high-powered fields recommended per specimen. Compared to conventional t-testing of means, hierarchical linear modeling was associated with substantial reductions in enrollment size required (n = 25➔n = 13) to detect the observed increases in sTIL/PD-L1.
CONCLUSION: mIF is useful for quantifying treatment-related dynamic changes in sTILs/PD-L1 and is concordant with clinical assays, but with greater precision. Hierarchical linear modeling can mitigate the effects of intratumoral heterogeneity on immune cell count estimations, allowing for more efficient detection of treatment-related pharmocodynamic effects in the context of clinical trials.
TRIAL REGISTRATION: NCT02950259
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