528 research outputs found
Fiber absorption measurement errors resulting from re-emission of radiation
We show that errors in the absorption measured in rare-earth-doped fibers can exceed 50% and severely distort the spectral shape. This is a result of re-emission in fibers with overlapping absorption and emission spectra
Infection-generated electric field in gut epithelium drives bidirectional migration of macrophages.
Many bacterial pathogens hijack macrophages to egress from the port of entry to the lymphatic drainage and/or bloodstream, causing dissemination of life-threatening infections. However, the underlying mechanisms are not well understood. Here, we report that Salmonella infection generates directional electric fields (EFs) in the follicle-associated epithelium of mouse cecum. In vitro application of an EF, mimicking the infection-generated electric field (IGEF), induces directional migration of primary mouse macrophages to the anode, which is reversed to the cathode upon Salmonella infection. This infection-dependent directional switch is independent of the Salmonella pathogenicity island 1 (SPI-1) type III secretion system. The switch is accompanied by a reduction of sialic acids on glycosylated surface components during phagocytosis of bacteria, which is absent in macrophages challenged by microspheres. Moreover, enzymatic cleavage of terminally exposed sialic acids reduces macrophage surface negativity and severely impairs directional migration of macrophages in response to an EF. Based on these findings, we propose that macrophages are attracted to the site of infection by a combination of chemotaxis and galvanotaxis; after phagocytosis of bacteria, surface electrical properties of the macrophage change, and galvanotaxis directs the cells away from the site of infection
Frequency and Outcomes of Abnormal Imaging in Patients With Cirrhosis Enrolled in a Hepatocellular Carcinoma Surveillance Program
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148235/1/lt25398_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148235/2/lt25398.pd
A novel auxiliary subunit critical to BK channel function in caenorhabditis elegans
The BK channel is a Ca(2+)- and voltage-gated potassium channel with many important physiological functions. To identify proteins important to its function in vivo, we screened for C. elegans mutants that suppressed a lethargic phenotype caused by expressing a gain-of-function (gf) isoform of the BK channel α-subunit SLO-1. BKIP-1, a small peptide with no significant homology to any previously characterized molecules was thus identified. BKIP-1 and SLO-1 showed similar expression and subcellular localization patterns, and appeared to interact physically through discrete domains. bkip-1 loss-of-function (lf) mutants phenocopied slo-1(lf) mutants in behavior and synaptic transmission, and suppressed the lethargy, egg-laying defect, and deficient neurotransmitter release caused by SLO-1(gf). In heterologous expression systems, BKIP-1 decreased the activation rate and shifted the conductance-voltage (G-V) relationship of SLO-1 in a Ca(2+)-dependent manner, and increased SLO-1 surface expression. Thus, BKIP-1 is a novel auxiliary subunit critical to SLO-1 function in vivo
Clinical and basic implications of dynamic T cell receptor clonotyping in hematopoietic cell transplantation
TCR repertoire diversification constitutes a foundation for successful immune reconstitution after allogeneic hematopoietic cell transplantation (allo-HCT). Deep TCR V beta sequencing of 135 serial specimens from a cohort of 35 allo-HCT recipients/donors was performed to dissect posttransplant TCR architecture and dynamics. Paired analysis of clonotypic repertoires showed a minimal overlap with donor expansions. Rarefied and hyperexpanded clonotypic patterns were hallmarks of T cell reconstitution and influenced clinical outcomes. Donor and pretransplant TCR diversity as well as divergence of class I human leukocyte antigen genotypes were major predictors of recipient TCR repertoire recovery. Complementary determining region 3-based specificity spectrum analysis indicated a predominant expansion of pathogen- and tumor-associated clonotypes in the late post-allo-HCT phase, while autoreactive clones were more expanded in the case of graft-versus-host disease occurrence. These findings shed light on post-allo-HCT adaptive immune reconstitution processes and possibly help in tracking alloreactive responses
Comparison of heavy-ion transport simulations: Collision integral with pions and Î resonances in a box
We compare ten transport codes for a system confined in a box, aiming at
improved handling of the production of resonances and pions, which is
indispensable for constraining high-density symmetry energy from observables
such as the yield ratio in heavy-ion collisions. The system in a
box is initialized with nucleons at saturation density and at 60 MeV
temperature. The reactions and
are implemented, but the Pauli blocking and the
mean-field potential are deactivated in the present comparison. Results are
compared to those from the two reference cases of a chemically equilibrated
ideal gas mixture and of the rate equation. In the results of the numbers of
and , deviations from the reference values are observed in many
codes, and they depend significantly on the size of the time step. These
deviations are tied to different ways in ordering the sequence of collisions
and decays, that take place in the same time step. Better agreements are seen
in the reaction rates and the number ratios among the isospin species of
and . These are, however, affected by the correlations, which are
absent in the Boltzmann equation, but are induced by the way particle
scatterings are treated in transport calculations. The uncertainty in the
transport-code predictions of the ratio for the system
initialized at n/p = 1.5, after letting the existing resonances decay,
is found to be within a few percent, which is sufficiently small so that it
does not strongly impact constraining the high-density symmetry energy from
heavy-ion collisions. Most of the sources of uncertainties have been
understood, and individual codes may be further improved. This investigation
will be extended in the future to heavy-ion collisions to ensure the problems
identified here remain under control.Comment: 36 pages, 27 figures; a new Fig. 21 and revised results from some
codes, achieving improved and consistent understandin
Regulation of Embryonic and Induced Pluripotency by Aurora Kinase-p53 Signaling
SummaryMany signals must be integrated to maintain self-renewal and pluripotency in embryonic stem cells (ESCs) and to enable induced pluripotent stem cell (iPSC) reprogramming. However, the exact molecular regulatory mechanisms remain elusive. To unravel the essential internal and external signals required for sustaining the ESC state, we conducted a short hairpin (sh) RNA screen of 104 ESC-associated phosphoregulators. Depletion of one such molecule, aurora kinase A (Aurka), resulted in compromised self-renewal and consequent differentiation. By integrating global gene expression and computational analyses, we discovered that loss of Aurka leads to upregulated p53 activity that triggers ESC differentiation. Specifically, Aurka regulates pluripotency through phosphorylation-mediated inhibition of p53-directed ectodermal and mesodermal gene expression. Phosphorylation of p53 not only impairs p53-induced ESC differentiation but also p53-mediated suppression of iPSC reprogramming. Our studies demonstrate an essential role for Aurka-p53 signaling in the regulation of self-renewal, differentiation, and somatic cell reprogramming
Measurement of quarkonium production at forward rapidity in pp collisions at âs=7 TeV
The inclusive production cross sections at forward rapidity of J/Ï , Ï(2S) , ΄ (1S) and ΄ (2S) are measured in pp collisions at sâ=7 TeV with the ALICE detector at the LHC. The analysis is based on a data sample corresponding to an integrated luminosity of 1.35 pbâŸÂč . Quarkonia are reconstructed in the dimuon-decay channel and the signal yields are evaluated by fitting the ÎŒ+ÎŒâ invariant mass distributions. The differential production cross sections are measured as a function of the transverse momentum pT and rapidity y , over the ranges 0<pT<20 GeV/c for J/Ï , 0<pT<12 GeV/c for all other resonances and for \(2.5 . The measured cross sections integrated over pT and y , and assuming unpolarized quarkonia, are: ÏJ/Ï=6.69±0.04±0.63 ÎŒ b, ÏÏ(2S)=1.13±0.07±0.19 ÎŒ b, Ï΄(1S)=54.2±5.0±6.7 nb and Ï΄(2S)=18.4±3.7±2.9 nb, where the first uncertainty is statistical and the second one is systematic. The results are compared to measurements performed by other LHC experiments and to theoretical models
Event-by-event mean pT fluctuations in pp and PbâPb collisions at the LHC
Event-by-event fluctuations of the mean transverse momentum of charged particles produced in pp collisions at TeX TeX 0.9, 2.76 and 7 TeV, and PbâPb collisions at TeX TeX 2.76 TeV are studied as a function of the charged-particle multiplicity using the ALICE detector at the LHC. Dynamical fluctuations indicative of correlated particle emission are observed in all systems. The results in pp collisions show little dependence on collision energy. The Monte Carlo event generators PYTHIA and PHOJET are in qualitative agreement with the data. Peripheral PbâPb data exhibit a similar multiplicity dependence as that observed in pp. In central PbâPb, the results deviate from this trend, featuring a significant reduction of the fluctuation strength. The results in PbâPb are in qualitative agreement with previous measurements in AuâAu at lower collision energies and with expectations from models that incorporate collective phenomena
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