2,617 research outputs found
Chinese Expert Consensus on Critical Care Ultrasound Applications at COVID-19 Pandemic
The spread of new coronavirus (SARS-Cov-2) follows a different pattern than previous respiratory viruses, posing a serious public health risk worldwide. World Health Organization (WHO) named the disease as COVID-19 and declared it a pandemic. COVID-19 is characterized by highly contagious nature, rapid transmission, swift clinical course, profound worldwide impact, and high mortality among critically ill patients. Chest X-ray, computerized tomography (CT), and ultrasound are commonly used imaging modalities. Among them, ultrasound, due to its portability and non-invasiveness, can be easily moved to the bedside for examination at any time. In addition, with use of 4G or 5G networks, remote ultrasound consultation can also be performed, which allows ultrasound to be used in isolated medial areas. Besides, the contact surface of ultrasound probe with patients is small and easy to be disinfected. Therefore, ultrasound has gotten lots of positive feedbacks from the frontline healthcare workers, and it has played an indispensable role in the course of COVID-19 diagnosis and follow up
Current understanding of CTLA-4: from mechanism to autoimmune diseases
Autoimmune diseases (ADs) are characterized by the production of autoreactive lymphocytes, immune responses to self-antigens, and inflammation in related tissues and organs. Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is majorly expressed in activated T cells and works as a critical regulator in the inflammatory response. In this review, we first describe the structure, expression, and how the signaling pathways of CTLA-4 participate in reducing effector T-cell activity and enhancing the immunomodulatory ability of regulatory T (Treg) cells to reduce immune response, maintain immune homeostasis, and maintain autoimmune silence. We then focused on the correlation between CTLA-4 and different ADs and how this molecule regulates the immune activity of the diseases and inhibits the onset, progression, and pathology of various ADs. Finally, we summarized the current progress of CTLA-4 as a therapeutic target for various ADs
Observation of Effective Pseudospin Scattering in ZrSiS
3D Dirac semimetals are an emerging class of materials that possess
topological electronic states with a Dirac dispersion in their bulk. In
nodal-line Dirac semimetals, the conductance and valence bands connect along a
closed path in momentum space, leading to the prediction of pseudospin vortex
rings and pseudospin skyrmions. Here, we use Fourier transform scanning
tunneling spectroscopy (FT-STS) at 4.5 K to resolve quasiparticle interference
(QPI) patterns at single defect centers on the surface of the line nodal
semimetal zirconium silicon sulfide (ZrSiS). Our QPI measurements show
pseudospin conservation at energies close to the line node. In addition, we
determine the Fermi velocity to be eV {\AA} in the
{\Gamma}-M direction ~300 meV above the Fermi energy , and the line node
to be ~140 meV above . More importantly, we find that certain scatterers
can introduce energy-dependent non-preservation of pseudospins, giving rise to
effective scattering between states with opposite valley pseudospin deep inside
valence and conduction bands. Further investigations of quasiparticle
interference at the atomic level will aid defect engineering at the synthesis
level, needed for the development of lower-power electronics via
dissipationless electronic transport in the future
A Characterization of Scale Invariant Responses in Enzymatic Networks
An ubiquitous property of biological sensory systems is adaptation: a step
increase in stimulus triggers an initial change in a biochemical or
physiological response, followed by a more gradual relaxation toward a basal,
pre-stimulus level. Adaptation helps maintain essential variables within
acceptable bounds and allows organisms to readjust themselves to an optimum and
non-saturating sensitivity range when faced with a prolonged change in their
environment. Recently, it was shown theoretically and experimentally that many
adapting systems, both at the organism and single-cell level, enjoy a
remarkable additional feature: scale invariance, meaning that the initial,
transient behavior remains (approximately) the same even when the background
signal level is scaled. In this work, we set out to investigate under what
conditions a broadly used model of biochemical enzymatic networks will exhibit
scale-invariant behavior. An exhaustive computational study led us to discover
a new property of surprising simplicity and generality, uniform linearizations
with fast output (ULFO), whose validity we show is both necessary and
sufficient for scale invariance of enzymatic networks. Based on this study, we
go on to develop a mathematical explanation of how ULFO results in scale
invariance. Our work provides a surprisingly consistent, simple, and general
framework for understanding this phenomenon, and results in concrete
experimental predictions
The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)
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Off-line and Real-time Evaluations of Eastern-Shore Sensors With a Generalized Detection Performance Monitoring System
SHA/UM/6-8The primary objectives of this study are to develop a detector performance monitoring system for both off-line and on-line applications, and to implement such a system for the Eastern Shore region\u2019s current and proposed sensors, including: evaluate the data quality and reliability of the six sensors deployed in the Eastern Shore region; assess the applicability of the six sensors in the Eastern Shore region for supporting various traffic monitoring and congestion-control strategies; and analyze the data applicability and effectiveness of the proposed 14 more sensors for the Eastern Shore region for traffic monitoring, congestion control, or emergency evaluation, based on their proposed deployment locations. The first product of this study is a set of guidelines for selecting the deployment locations for traffic sensors in the Easter Shore region for different purposes, such as speed monitoring, signal design, or congestion control. The second product is an innovative, multi-stage control model for traffic professionals to efficiently assess the quality of massive speed and flow rate data produced from a deployed detector. Based on the quality assessment results, the responsible maintenance engineers/staff can better classify the operational status of each deployed detector, including \u201cfor speed-monitoring only,\u201d \u201cfor traffic control and management,\u201d \u201cneed to replace with new detector,\u201d and \u201cneed a field calibration to improve the detection accuracy.\u201
N-Acetylglucosamine Induces White to Opaque Switching, a Mating Prerequisite in Candida albicans
To mate, the fungal pathogen Candida albicans must undergo homozygosis at the mating-type locus and then switch from the white to opaque phenotype. Paradoxically, opaque cells were found to be unstable at physiological temperature, suggesting that mating had little chance of occurring in the host, the main niche of C. albicans. Recently, however, it was demonstrated that high levels of CO2, equivalent to those found in the host gastrointestinal tract and select tissues, induced the white to opaque switch at physiological temperature, providing a possible resolution to the paradox. Here, we demonstrate that a second signal, N-acetylglucosamine (GlcNAc), a monosaccharide produced primarily by gastrointestinal tract bacteria, also serves as a potent inducer of white to opaque switching and functions primarily through the Ras1/cAMP pathway and phosphorylated Wor1, the gene product of the master switch locus. Our results therefore suggest that signals produced by bacterial co-members of the gastrointestinal tract microbiota regulate switching and therefore mating of C. albicans
Heme Oxygenase Isoforms Differ in Their Subcellular Trafficking during Hypoxia and Are Differentially Modulated by Cytochrome P450 Reductase
Heme oxygenase (HO) degrades heme in concert with NADPH cytochrome P450 reductase (CPR) which donates electrons to the reaction. Earlier studies reveal the importance of the hydrophobic carboxy-terminus of HO-1 for anchorage to the endoplasmic reticulum (ER) which facilitates the interaction with CPR. In addition, HO-1 has been shown to undergo regulated intramembrane proteolysis of the carboxy-terminus during hypoxia and subsequent translocation to the nucleus. Translocated nuclear HO-1 was demonstrated to alter binding of transcription factors and to alter gene expression. Little is known about the homologous membrane anchor of the HO-2 isoform. The current work is the first systematic analysis in a eukaryotic system that demonstrates the crucial role of the membrane anchor of HO-2 for localization at the endoplasmic reticulum, oligomerization and interaction with CPR. We show that although the carboxy-terminal deletion mutant of HO-2 is found in the nucleus, translocation of HO-2 to the nucleus does not occur under conditions of hypoxia. Thus, we demonstrate that proteolytic regulation and nuclear translocation under hypoxic conditions is specific for HO-1. In addition we show for the first time that CPR prevents this translocation and promotes oligomerization of HO-1. Based on these findings, CPR may modulate gene expression via the amount of nuclear HO-1. This is of particular relevance as CPR is a highly polymorphic gene and deficiency syndromes of CPR have been described in humans
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