2,229 research outputs found

    Tissue Factor, Blood Coagulation, and Beyond: An Overview

    Get PDF
    Emerging evidence shows a broad spectrum of biological functions of tissue factor (TF). TF classical role in initiating the extrinsic blood coagulation and its direct thrombotic action in close relation to cardiovascular risks have long been established. TF overexpression/hypercoagulability often observed in many clinical conditions certainly expands its role in proinflammation, diabetes, obesity, cardiovascular diseases, angiogenesis, tumor metastasis, wound repairs, embryonic development, cell adhesion/migration, innate immunity, infection, pregnancy loss, and many others. This paper broadly covers seminal observations to discuss TF pathogenic roles in relation to diverse disease development or manifestation. Biochemically, extracellular TF signaling interfaced through protease-activated receptors (PARs) elicits cellular activation and inflammatory responses. TF diverse biological roles are associated with either coagulation-dependent or noncoagulation-mediated actions. Apparently, TF hypercoagulability refuels a coagulation-inflammation-thrombosis circuit in “autocrine” or “paracrine” fashions, which triggers a wide spectrum of pathophysiology. Accordingly, TF suppression, anticoagulation, PAR blockade, or general anti-inflammation offers an array of therapeutical benefits for easing diverse pathological conditions

    Simulated X-ray Spectra From Ionized Wind-Blown Nebulae around Massive Stars

    Full text link
    Using an ionization gasdynamics code, we simulate a model of the wind-blown bubble around a 40 solar mass star. We use this to compute the X-ray spectra from the bubble, which can be directly compared to observations. We outline our methods and techniques for these computations, and contrast them with previous calculations. Our simulated X-ray spectra compare reasonably well with observed spectra of Wolf-Rayet bubbles. They suggest that X-ray nebulae around massive stars may not be easily detectable, consistent with observations.Comment: 7 pages, 2 figures. Revised and shortened version following referee comments. Accepted to High Energy Density Physic

    Dusty Wind-Blown Bubbles

    Full text link
    Spurred by recent observations of 24 micron emission within wind-blown bubbles, we study the role that dust can play in such environments, and build an approximate model of a particular wind-blown bubble, `N49.' First, we model the observations with a dusty wind-blown bubble, and then ask whether dust could survive within N49 to its present age (estimated to be 5x10^5 to 10^6 years). We find that dust sputtering and especially dust-gas friction would imply relatively short timescales (t ~ 10^4 years) for dust survival in the wind-shocked region of the bubble. To explain the 24 micron emission, we postulate that the grains are replenished within the wind-blown bubble by destruction of embedded, dense cloudlets of ISM gas that have been over-run by the expanding wind-blown bubble. We calculate the ablation timescales for cloudlets within N49 and find approximate parameters for the embedded cloudlets that can replenish the dust; the parameters for the cloudlets are roughly similar to those observed in other nebula. Such dust will have an important effect on the bubble: including simple dust cooling in a wind-blown bubble model for N49, we find that the luminosity is higher by approximately a factor of six at a bubble age of about 10^4 years. At ages of 10^7 years, the energy contained in the bubble is lower by about a factor of eight if dust is included; if dust must be replenished within the bubble, the associated accompanying gas mass will also be very important to wind-blown bubble cooling and evolution. While more detailed models are certainly called for, this work illustrates the possible strong importance of dust in wind-blown bubbles, and is a first step toward models of dusty, wind-blown bubbles.Comment: 13 pages, 14 figures, Accepted to Ap

    GPS multi-receiver direct position estimation for aerial applications

    Get PDF
    Modern aviation safety increasingly depends on reliable GPS services, while signal degrading effects such as multipath and masking often occur during critical flight phases, such as take-off and landing. In this regard, we propose Multi-Receiver Direct Position Estimation (MR-DPE), which operates a network of DPE receivers to enhance GPS measurement certainty in degraded signal environments. A DPE receiver directly estimates navigation solutions in the PVT domain with a maximum-likelihood approach, bypassing the intermediate range measurements. Whereas prior works have shown the enhanced measurement certainty of DPE under weak signals, MR-DPE provides further improvement by leveraging the information redundancy and the geometric diversity provided by the network of receivers and antennas. We implemented MR-DPE using software-defined radio and conducted comprehensive, full-scale flight experiments, a first for DPE-related works. A wide range of flight profiles were explored, especially those prone to signal multipath and masking, and preliminary analyses were performed on the data collected to ensure the conceptual validity of MR-DPE

    Colloidal toxic trace metals in urban riverine and estuarine waters of Yantai City, southern coast of North Yellow Sea

    Get PDF
    The environmental characteristics of colloidal toxic trace metals Cd, Cu and Pb in riverine and estuarine waters collected from two urban rivers of Yantai City in eastern China, the Guangdang and Xin'an Rivers, were investigated using a modified centrifugal ultrafiltration (CUF) method in conjunction with acid extraction and inductively coupled plasma mass spectrometry. The target metals in dissolved pool were divided into four CUF fractions, i.e. <1 kDa, 1-3 kDa, 3-10 kDa and 10 kDa-0.2 mu m, and the results showed that colloidal Cd, Cu and Pb were dominated by 1-10 kDa (1-3 and 3-10 kDa), 1-3 kDa and 10 kDa-0.2 lm fractions, respectively. The coagulation/flocculation of low-molecular-weight (1-10 kDa) colloidal Cd and Cu in the estuaries was obvious and strong, while the enrichment of dissolved Pb in the 10 kDa-0.2 lm fraction may be mainly related to its biogeochemical interactions with Fe-oxides, which is easy to occur in macromolecular colloids. In addition, the actual molecular weight cutoffs (MWCOs) of the three used CUF units with nominal MWCOs of 1, 3 and 10 kDa were determined to be 4.9, 8.5 and 33.9 kDa, respectively, indicating that membrane calibration is essential for explaining the actual fraction of dissolved trace metals and verifying the integrity of ultrafiltration membrane. Overall, the results in this study provide a further understanding of the heterogeneity in biogeochemical features, migration and fate of toxic trace metals in aquatic ecosystems, especially that of the river-sea mixing zone. (C) 2019 Elsevier B.V. All rights reserved

    Comparison of the effect of environmental temperature on rabbits and cattle, Part 2, Influence of raising environmental temperature on the physiological reactions of rabbits and cattle.

    Get PDF
    The bulletin reports on Department of Dairy Husbandry Research Project 125, Climatic Factors--P. [3].Digitized 2007 AES.Includes bibliographical references (pages 15-17)

    Examination Of The Influence Of Service Quality On Membership Renewal In Fitness Centers In San Francisco Bay Area

    Get PDF
    Corporations have to learn how to satisfy their customers&rsquo; various demands as the era of interactivity with customers has emerged (Pepper &amp; Rogers, 1999). For fitness center, customers&rsquo; demands are increasing and diversified. Therefore, service quality is an index of quality assessment from customers for service-producing industries. Furthermore, the concept of corporate expansion and customer relationship has become the foundation of service-providers for higher profitability through customers&rsquo; renewal of membership. The main purpose of this study is to evaluate the impact of service quality on the renewal willingness of fitness center membership. Customers from four fitness centers in the San Francisco Bay Area, USA, were randomly selected for this survey. A total of 50 subjects participated in this survey. The data was analyzed by multiple regression and stepwise regression. The result indicated that the service quality has positive influence on the renewal willingness of membership

    Protein kinase C is a calcium sensor for presynaptic short-term plasticity

    Get PDF
    In presynaptic boutons, calcium (Ca2+) triggers both neurotransmitter release and short-term synaptic plasticity. Whereas synaptotagmins are known to mediate vesicle fusion through binding of high local Ca2+ to their C2 domains, the proteins that sense smaller global Ca2+ increases to produce short-term plasticity have remained elusive. Here, we identify a Ca2+ sensor for post-tetanic potentiation (PTP), a form of plasticity thought to underlie short-term memory. We find that at the functionally mature calyx of Held synapse the Ca2+-dependent protein kinase C isoforms α and β are necessary for PTP, and the expression of PKCβ in PKCαβ double knockout mice rescues PTP. Disruption of Ca2+ binding to the PKCβ C2 domain specifically prevents PTP without impairing other PKCβ-dependent forms of synaptic enhancement. We conclude that different C2-domain-containing presynaptic proteins are engaged by different Ca2+ signals, and that Ca2+ increases evoked by tetanic stimulation are sensed by PKCβ to produce PTP. DOI: http://dx.doi.org/10.7554/eLife.03011.00
    corecore