1,863 research outputs found

    Cross talk between the lungs in piglets

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    Case Report: man on antiretroviral therapy with painful thighs

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    A 54 year old man presented with increasing pain in both thighs for three months during a follow up visit at the antiretroviral therapy (ART) clinic of Queen Elizabeth Central Hospital

    Technology production of carbon nanofibers and methane-hydrogen mixture in the reactor of catalytic decomposition natural gas

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    This paper presents a technology of production methane-hydrogen mixture for use as motor fuel. We investigated different the various modes and selected the most effective catalysts for this process. Established optimal condition for carry out this process

    Allergen-specific subcutaneous immunotherapy in allergic asthma: immunologic mechanisms and improvement

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    Allergic asthma is a disease characterized by persistent allergen-driven airway inflammation, remodeling, and airway hyperresponsiveness. CD4+ T-cells, especially T-helper type 2 cells, play a critical role in orchestrating the disease process through the release of the cytokines IL-4, IL-5, and IL-13. Allergen-specific immunotherapy (SIT) is currently the only treatment with a long-term effect via modifying the natural course of allergy by interfering with the underlying immunological mechanisms. However, although SIT is effective in allergic rhinitis and insect venom allergy, in allergic asthma it seldom results in complete alleviation of the symptoms. Improvement of SIT is needed to enhance its efficacy in asthmatic patients. Herein, the immunoregulatory mechanisms underlying the beneficial effects of SIT are discussed with the ultimate aim to improve its treatment efficacy

    Interleukin-5 Potentiates Sulfidopeptide Leukotriene Production by Human Eosinophils

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    Interleukin-5 (IL-5) has been shown to be a selective eosinophil growth and differentiation factor. In the present study, the effect of recombinant human IL-5 on human eosinophil sulfidopeptide leukotriene production was investigated. IL-5 did not affect leukotriene synthesis in unstimulated eosinophils. However, IL-5 potentiated leukotriene synthesis by eosinophils stimulated with serum treated zymosan (STZ) or the calcium ionophore A23187 by 69% and 135%, respectively. The priming effect of IL-5 was dose dependent, with significant stimulation occurring at 1 000 U/ml for STZ and 100-1 000 U/ml for A23187. Pre-incubation with IL-5 did not increase leukotriene synthesis further

    Moderating the neutralist–selectionist debate: exactly which propositions are we debating, and which arguments are valid?

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    Half a century after its foundation, the neutral theory of molecular evolution continues to attract controversy. The debate has been hampered by the coexistence of different interpretations of the core proposition of the neutral theory, the ‘neutral mutation–random drift’ hypothesis. In this review, we trace the origins of these ambiguities and suggest potential solutions. We highlight the difference between the original, the revised and the nearly neutral hypothesis, and re-emphasise that none of them equates to the null hypothesis of strict neutrality. We distinguish the neutral hypothesis of protein evolution, the main focus of the ongoing debate, from the neutral hypotheses of genomic and functional DNA evolution, which for many species are generally accepted. We advocate a further distinction between a narrow and an extended neutral hypothesis (of which the latter posits that random non-conservative amino acid substitutions can cause non-ecological phenotypic divergence), and we discuss the implications for evolutionary biology beyond the domain of molecular evolution. We furthermore point out that the debate has widened from its initial focus on point mutations, and also concerns the fitness effects of large-scale mutations, which can alter the dosage of genes and regulatory sequences. We evaluate the validity of neutralist and selectionist arguments and find that the tested predictions, apart from being sensitive to violation of underlying assumptions, are often derived from the null hypothesis of strict neutrality, or equally consistent with the opposing selectionist hypothesis, except when assuming molecular panselectionism. Our review aims to facilitate a constructive neutralist–selectionist debate, and thereby to contribute to answering a key question of evolutionary biology: what proportions of amino acid and nucleotide substitutions and polymorphisms are adaptive?

    Post exposure prophylaxis of HIV transmission after occupational injuries in Queen Elizabeth Central Hospital, Blantyre, Malawi, 2003 – 2008

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    Health care worker (HCW) in Malawi may acquire HIV infection through occupational injuries, in particular since HIV prevalence among inpatients and incidence of occupational injuries are high. A post exposure prophylaxis (PEP) programme for occupational injuries at QueenElizabeth Central Hospital (QECH) commenced in 2003. We performed an audit of this programme from 2003 through 2008. 203 Occupational injuries were reported. The majority were needle stick injuries (76.3%). Half of the clients were in a training position. A dual ART regimen was most frequently prescribed. Triple therapy use increased over time and wasmore frequent in expatriate students. Many nurses and clinical officers were not fully vaccinated for HBV. Based on previous incidence data, occupational injuries were likely to be underreported. Data on side effects were incomplete, however PEP discontinuation due to side effects occurredonly twice. Follow up visits were poorly attended, therefore the efficacy of PEP could not be evaluated. Prevention efforts for occupational injuries should be increased and specifically target HCWs in training positions.Measures to improve quality of the PEP programme include effective publicity campaigns, compulsory Hepatitis B vaccination and active tracing of HCWs who default follow up after PEP

    Climate model boundary conditions for four Cretaceous time slices

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    International audienceGeneral circulation models (GCMs) are useful tools for investigating the characteristics and dynamics of past climates. Understanding of past climates contributes significantly to our overall understanding of Earth's climate system. One of the most time consuming, and often daunting, tasks facing the paleoclimate modeler, particularly those without a geological background, is the production of surface boundary conditions for past time periods. These boundary conditions consist of, at a minimum, continental configurations derived from plate tectonic modeling, topography, bathymetry, and a vegetation distribution. Typically, each researcher develops a unique set of boundary conditions for use in their simulations. Thus, unlike simulations of modern climate, basic assumptions in paleo surface boundary conditions can vary from researcher to researcher. This makes comparisons between results from multiple researchers difficult and, thus, hinders the integration of studies across the broader community. Unless special changes to surface conditions are warranted, researcher dependent boundary conditions are not the most efficient way to proceed in paleoclimate investigations. Here we present surface boundary conditions (land-sea distribution, paleotopography, paleobathymetry, and paleovegetation distribution) for four Cretaceous time slices (120 Ma, 110 Ma, 90 Ma, and 70 Ma). These boundary conditions are modified from base datasets to be appropriate for incorporation into numerical studies of Earth's climate and are available in NetCDF format upon request from the lead author. The land-sea distribution, bathymetry, and topography are based on the 1°×1° (latitude × longitude) paleo Digital Elevation Models (paleoDEMs) of Christopher Scotese. Those paleoDEMs were adjusted using the paleogeographical reconstructions of Ronald Blakey (Northern Arizona University) and published literature and were then modified for use in GCMs. The paleovegetation distribution is based on published data and reconstructions and consultation with members of the paleobotanical community and is represented as generalized biomes that should be easily translatable to many vegetation-modeling schemes

    Rapid Urine-Based Screening for Tuberculosis to Reduce AIDS-Related Mortality in Hospitalized Patients in Africa (STAMP) Trial Protocol

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    Trial protocol for the STAMP trial- a multi-country (Malawi and South Africa) individually randomised clinical trial to determine the impact on early mortality of the addition of rapid, urine-based TB screening to the standard of care TB screening in HIV-infected patients requiring admission to medical wards in hospitals in southern Africa

    Chromosome-scale genome assemblies of aphids reveal extensively rearranged autosomes and long-term conservation of the X chromosome

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    Chromosome rearrangements are arguably the most dramatic type of mutations, often leading to rapid evolution and speciation. However, chromosome dynamics have only been studied at the sequence level in a small number of model systems. In insects, Diptera and Lepidoptera have conserved genome structure at the scale of whole chromosomes or chromosome arms. Whether this reflects the diversity of insect genome evolution is questionable given that many species exhibit rapid karyotype evolution. Here, we investigate chromosome evolution in aphids-an important group of hemipteran plant pests-using newly generated chromosome-scale genome assemblies of the green peach aphid (Myzus persicae) and the pea aphid (Acyrthosiphon pisum), and a previously published assembly of the corn-leaf aphid (Rhopalosiphum maidis). We find that aphid autosomes have undergone dramatic reorganization over the last 30 My, to the extent that chromosome homology cannot be determined between aphids from the tribes Macrosiphini (Myzus persicae and Acyrthosiphon pisum) and Aphidini (Rhopalosiphum maidis). In contrast, gene content of the aphid sex (X) chromosome remained unchanged despite rapid sequence evolution, low gene expression, and high transposable element load. To test whether rapid evolution of genome structure is a hallmark of Hemiptera, we compared our aphid assemblies with chromosome-scale assemblies of two blood-feeding Hemiptera (Rhodnius prolixus and Triatoma rubrofasciata). Despite being more diverged, the blood-feeding hemipterans have conserved synteny. The exceptional rate of structural evolution of aphid autosomes renders them an important emerging model system for studying the role of large-scale genome rearrangements in evolution
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