907 research outputs found

    A new approach to non-invasive oxygenated mixed venous PCO(sub)2

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    A clinically practical technique was developed to calculate mixed venous CO2 partial pressure for the calculation of cardiac output by the Fick technique. The Fick principle states that the cardiac output is equal to the CO2 production divided by the arterio-venous CO2 content difference of the pulmonary vessels. A review of the principles involved in the various techniques used to estimate venous CO2 partial pressure is presented

    Overlapping Roles of CXCL13, Interleukin 7 Receptor α, and CCR7 Ligands in Lymph Node Development

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    Lymphoid tissue development is associated with local accumulation of CD4+ CD3− IL-7Rαhi hematopoietic cells that deliver lymphotoxin (LT)α1β2 signals to resident stromal cells. Previous studies have established an important role for CXCL13 (BLC) in the development of Peyer's patches (PP) and some peripheral lymph nodes (LNs), but the chemokine requirements for several LN types, including mesenteric LNs, remain undefined. Using CXCL13−/− mice that additionally carry the paucity of LN T cell mutation (plt/plt), we discovered that CCR7 ligands function in peripheral LN development. We also tested for a genetic interaction during LN development between CXCL13 and a cytokine receptor required in PP development, IL-7Rα. Mice deficient for both CXCL13 and IL-7Rα displayed a striking absence of LNs, including mesenteric LNs. These data extend the role of CXCL13 to the development of all LNs and establish a previously unappreciated role for IL-7Rα in this process. Both circulating and LN CD4+ CD3− IL-7Rαhi cells are shown to express LTα1β2 in an IL-7Rα–dependent manner. Furthermore, CXCL13 was found to be sufficient to mediate CD4+ CD3− IL-7Rαhi cell recruitment in vivo to an ectopic site. These findings indicate that CXCL13 and CCR7 ligands promote accumulation of CD4+ CD3− IL-7Rαhi cells, delivering IL-7Rα–dependent LTα1β2 signals critical for LN development

    Prevalence of Trypanosoma evansi in horses (Equus caballus) and donkeys (Equus asinus) in El-Bayadh district, southwestern Algeria

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    NO ABSTRACT AVAILABLETrypanosoma evansi is a parasite that causes surra in a variety of wild and domestic animals and is mainly transmitted by biting flies in Africa, Asia and Latin-America. Horses infected by Trypanosoma evansi present a chronic weight loss, icterus, oedema, anemia, abortions and neurological troubles. Due to this parasite, cases of human trypanosomiosis have been reported in different countries by contacting with infected animals. In this study, 206 healthy equines (177 horses and 29 donkeys) from El-Bayadh district, located in southwest Algeria, were tested for the presence of parasites in blood using Giemsa-stained blood films and for the presence of antibodies against T. evansi using CATT /T. evansi. While none of the equines showed detectable parasites in the blood, the individual seroprevalence of T. evansi was found to be 46.6% (CI 95%, 40.7-54.4%). Out of 98 positives samples, 56.1% (55/98) were shown at level 1 (+), 27.5% (27/98) at level 2 (++) and 16.3% (16/98) at level 3 (+++). The results show that out of 177 tested horses, 80 were seropositive to T. evansi, 45.2% (CI 95%, 37.8-52.5%) and out of 29 tested donkeys, 18 were seropositive to T. evansi, 62.1% (CI 95%, 44.4-79.7%). A questionnaire for the owners, targeted to associate risk factors for surra in horses, showed that environmental factors that are favorable for Tabanids, such as water and vegetation, but also promiscuity with dromedaries were positively associated with the seroprevalence rate in the horses. El-Bayadh district is a highly endemic region for surra in Algeria

    Measuring the Difference Between Pictures From Controlled and Uncontrolled Sources to Promote a Destination. A Deep Learning Approach

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    Promoting a destination is a major task for Destination Marketing Organizations (DMOs). Although DMOs control, to some extent, the information presented to travelers (controlled sources), there are other different sources of information (uncontrolled sources) that could project an unfavorable image of the destination. Measuring differences between information sources would help design strategies to mitigate negative factors. In this way, we propose a deep learning-based approach to automatically measure the changes between images from controlled and uncontrolled information sources. Our approach exempts experts from the time-consuming task of assessing enormous quantities of pictures to track changes. To our best knowledge, this work is the first work that focuses on this issue using technological paradigms. Notwithstanding this, our approach paves novel pathways to acquire strategic insights that can be harnessed for the augmentation of destination development, the refinement of recommendation systems, the analysis of online travel reviews, and myriad other pertinent domains

    Aberrant T cell differentiation in the absence of Dicer

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    Dicer is an RNaseIII-like enzyme that is required for generating short interfering RNAs and microRNAs. The latter have been implicated in regulating cell fate determination in invertebrates and vertebrates. To test the requirement for Dicer in cell-lineage decisions in a mammalian organism, we have generated a conditional allele of dicer-1 (dcr-1) in the mouse. Specific deletion of dcr-1 in the T cell lineage resulted in impaired T cell development and aberrant T helper cell differentiation and cytokine production. A severe block in peripheral CD8+ T cell development was observed upon dcr-1 deletion in the thymus. However, Dicer-deficient CD4+ T cells, although reduced in numbers, were viable and could be analyzed further. These cells were defective in microRNA processing, and upon stimulation they proliferated poorly and underwent increased apoptosis. Independent of their proliferation defect, Dicer-deficient helper T cells preferentially expressed interferon-γ, the hallmark effector cytokine of the Th1 lineage

    Cathode & Electromagnet Qualification Status and Power Processing Unit Development Update for the Ascendant Sub-kW Transcelestial Electric Propulsion System

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    A review of the component-level flight qualification efforts and power processing unit development status of the Ascendant Sub-kW Transcelestial Electric Propulsion System (ASTRAEUS) program is presented. Component-level qualification efforts were undertaken for the system’s ultra-compact heaterless LaB6 hollow cathode and electromagnets, both of which employ designs bespoke to ASTRAEUS, as they represent the highest failure risks for the thruster. Through parallel long-duration wear and ignition tests, the ASTRAEUS cathode demonstrated invariant discharge performance over more than 5000 h of operation at its maximum operating current of 4 A and demonstrated more than 25,000 ignition cycles. The ASTRAEUS electromagnets completed their environmental qualification through a demonstration of more than 1200 deep thermal cycles with no indication of coil degradation (the test articles previously completed qualification-level vibration and shock testing). ASTRAEUS’s prototype power processing unit has demonstrated more than 92% total power conversion efficiency and class-leading power density & specific power density of 4.5 W/cm3 & 1670 W/kg, respectively. The various power converters found in the ASTRAEUS power processing unit are reviewed with a focus on the methods by which such high performance was achieved
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