402 research outputs found

    Comparative growth and static allometry in the genus Chlorocebus

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    Characterizing variation in growth across populations is critical to understanding multiple aspects of development in primates, including within-taxon developmental plasticity and the evolution of life history patterns. Growth in wild primates has often been reported and directly compared across larger taxonomic groups and within social groups, but comparisons are rarely investigated across widely dispersed populations of a single taxon. With the Vervet Phenome-Genome Project and the International Vervet Research Consortium, we trapped 936 vervet monkeys of all ages representing three populations (Kenyan pygerythrus, South African pygerythrus, and sabaeus from St. Kitts & Nevis). We gathered 10 different body measurements from each including mass, body breadth and length, segmental limb lengths, and chest circumference. To gain a better understanding of how ontogenetic patterns vary in these populations, we calculated bivariate allometry coefficients, derived using PCA on log-transformed and z-standardized trait values, and compared them to isometric vector coefficients. Within all population samples, around weaning age most traits showed a negative allometric relationship to body length. As each population ages, however, distinct patterns emerge, showing population differences in onset and intensity of growth among traits. In concordance with other analyses on growth in these populations, our results suggest that there exist relative differences in patterns of growth between Chlorocebus populations, further suggesting selection for unique developmental pathways in each

    The effect of concentration gradients on deflagration-to-detonation transition in a rectangular channel with and without obstructions : a numerical study

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    Explosions in homogeneous reactive mixtures have been widely studied both experimentally and numerically. However, in accident scenarios, mixtures are usually inhomogeneous due to the localized nature of most fuel releases, buoyancy effects and the finite time between release and ignition. It is imperative to determine whether mixture inhomogeneity can increase the explosion hazard beyond what is known for homogeneous mixtures. The present numerical investigation aims to study flame acceleration and transition to detonation in homogeneous and inhomogeneous hydrogen-air mixtures with two different average hydrogen concentrations in a horizontal rectangular channel. A density-based solver was implemented within the OpenFOAM CFD toolbox. The Harten–Lax–van Leer–Contact (HLLC) scheme was used for accurate shock capturing. A high-resolution grid is provided by using adaptive mesh refinement, which leads to 30 grid points per half reaction length (HRL). In agreement with previous experimental results, it is found that transverse concentration gradients can either strengthen or weaken flame acceleration, depending on average hydrogen concentration and channel obstruction. Comparing experiments and simulations, the paper analyses flame speed and pressure histories, identifies locations of detonation onset, and interprets the effects of concentration gradients

    Focal subarachnoid haemorrhage mimicking transient ischaemic attack - do we really need MRI in the acute stage?

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    Background: Acute non-traumatic focal subarachnoid haemorrhage (fSAH) is a rare transient ischaemic attack (TIA)-mimic. MRI is considered to be indispensable by some authors in order to avoid misdiagnosis, and subsequent improper therapy. We therefore evaluated the role of CT and MRI in the diagnosis of fSAH patients by comparing our cases to those from the literature. Methods: From 01/2010 to 12/2012 we retrospectively identified seven patients with transient neurological episodes due to fSAH, who had received unenhanced thin-sliced multiplanar CT and subsequent MRI within 3 days on a 1.5 T scanner. MRI protocol included at least fast-field-echo (FFE), diffusion-weighted imaging (DWI), T2-weighted fluid-attenuated inversion recovery (FLAIR) and time-of-flight (TOF) MRA sequences. By using MRI as gold-standard, we re-evaluated images and data from recent publications regarding the sensitivity to detect fSAH in unenhanced CT. Results: fSAH was detected by CT and by FFE and FLAIR on MRI in all of our own cases. However, DWI and T2w-spinecho sequences revealed fSAH in 3 of 7 and 4 of 6 cases respectively. Vascular imaging was negative in all cases. FFE-MRI revealed additional multiple microbleeds and superficial siderosis in 4 of 7 patients and 5 of 7 patients respectively. Including data from recently published literature CT scans delivered positive results for fSAH in 95 of 100 cases (95%), whereas MRI was positive for fSAH in 69 of 69 cases (100%). Conclusions: Thin-sliced unenhanced CT is a valuable emergency diagnostic tool to rule out intracranial haemorrhage including fSAH in patients with acute transient neurological episodes if immediate MRI is not available. However, MRI work-up is crucial and mandatorily has to be completed within the next 24-72 hours

    A neuroskeletal atlas: Spatial mapping and contextualization of axon subtypes innervating the long bones of C3H and B6 mice

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    Nerves in bone play well-established roles in pain and vasoregulation and have been associated with progression of skeletal disorders, including osteoporosis, fracture, arthritis, and tumor metastasis. However, isolation of the region-specific mechanisms underlying these relationships is limited by our lack of quantitative methods for neuroskeletal analysis and precise maps of skeletal innervation. To overcome these limitations, we developed an optimized workflow for imaging and quantitative analysis of axons in and around the bone, including validation of Baf53b-Cre in concert with R26R-tdTomato (Ai9) as a robust pan-neuronal reporter system for use in musculoskeletal tissues. In addition, we created comprehensive maps of sympathetic adrenergic and sensory peptidergic axons within and around the full length of the femur and tibia in two strains of mice (B6 and C3H). In the periosteum, these maps were related to the surrounding musculature, including entheses and myotendinous attachments to bone. Three distinct patterns of periosteal innervation (termed type I, II, III) were defined at sites that are important for bone pain, bone repair, and skeletal homeostasis. For the first time, our results establish a gradient of bone marrow axon density that increases from proximal to distal along the length of the tibia and define key regions of interest for neuroskeletal studies. Lastly, this information was related to major nerve branches and local maps of specialized mechanoreceptors. This detailed mapping and contextualization of the axonal subtypes innervating the skeleton is intended to serve as a guide during the design, implementation, and interpretation of future neuroskeletal studies and was compiled as a resource for the field as part of the NIH SPARC consortium. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

    Differential proteomics analysis of Frankliniella occidentalis immune response after infection with Tomato spotted wilt virus (Tospovirus)

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    Tomato spotted wilt virus (TSWV) is mainly vectored by Frankliniella occidentalis Pergande, and it potentially activates the vector's immune response. However, molecular background of the altered immune response is not clearly understood. Therefore, using a proteomic approach, we investigated the immune pathways that are activated in F. occidentalis larvae after 24 h exposure to TSWV. Two-dimensional isoelectric focusing/sodium dodecyl sulfate polyacrylamide gel electrophoresis (2D-IEF/SDS/PAGE) combined with mass spectrometry (MS), were used to identify proteins that were differentially expressed upon viral infection. High numbers of proteins were abundantly expressed in F. occidentalis exposed to TSWV (73%) compared to the non-exposed (27%), with the majority functionally linked to the innate immune system such as: signaling, stress response, defense response, translation, cellular lipids and nucleotide metabolism. Key proteins included: 70 kDa heat shock proteins, Ubiquitin and Dermcidin, among others, indicative of a responsive pattern of the vector's innate immune system to viral infection. © 2016 Elsevier Lt

    Morphological variation in the genus Chlorocebus: Ecogeographic and anthropogenically mediated variation in body mass, postcranial morphology, and growth

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    Objectives Direct comparative work in morphology and growth on widely dispersed wild primate taxa is rarely accomplished, yet critical to understanding ecogeographic variation, plastic local variation in response to human impacts, and variation in patterns of growth and sexual dimorphism. We investigated population variation in morphology and growth in response to geographic variables (i.e., latitude, altitude), climatic variables (i.e., temperature and rainfall), and human impacts in the vervet monkey (Chlorocebus spp.). Methods We trapped over 1,600 wild vervets from across Sub‐Saharan Africa and the Caribbean, and compared measurements of body mass, body length, and relative thigh, leg, and foot length in four well‐represented geographic samples: Ethiopia, Kenya, South Africa, and St. Kitts & Nevis. Results We found significant variation in body mass and length consistent with Bergmann\u27s Rule in adult females, and in adult males when excluding the St. Kitts & Nevis population, which was more sexually dimorphic. Contrary to Rensch\u27s Rule, although the South African population had the largest average body size, it was the least dimorphic. There was significant, although very small, variation in all limb segments in support for Allen\u27s Rule. Females in high human impact areas were heavier than those with moderate exposures, while those in low human impact areas were lighter; human impacts had no effect on males. Conclusions Vervet monkeys appear to have adapted to local climate as predicted by Bergmann\u27s and, less consistently, Allen\u27s Rule, while also responding in predicted ways to human impacts. To better understand deviations from predicted patterns will require further comparative work in vervets

    A Combination of Two Human Monoclonal Antibodies Limits Fetal Damage by Zika Virus in Macaques

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    Human infection by Zika virus (ZIKV) during pregnancy can lead to vertical transmission and fetal aberrations, including microcephaly. Prophylactic administration of antibodies can diminish or prevent ZIKV infection in animal models, but whether passive immunization can protect nonhuman primates and their fetuses during pregnancy has not been determined. Z004 and Z021 are neutralizing monoclonal antibodies to domain III of the envelope (EDIII) of ZIKV. Together the two antibodies protect nonpregnant macaques against infection even after Fc modifications to prevent antibody-dependent enhancement in vitro (ADE) and extend their half-lives. Here we report on prophylactic co-administration of the Fc-modified antibodies to pregnant rhesus macaques challenged 3 times with ZIKV during first and second trimester. The two antibodies did not entirely eliminate maternal viremia but limited vertical transmission protecting the fetus from neurologic damage. Thus, maternal passive immunization with two antibodies to EDIII can shield primate fetuses from the harmful effects of ZIKV

    Review of mass drug administration for malaria and its operational challenges.

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    Mass drug administration (MDA) was a component of many malaria programs during the eradication era, but later was seldomly deployed due to concerns regarding efficacy and feasibility and fear of accelerating drug resistance. Recently, however, there has been renewed interest in the role of MDA as an elimination tool. Following a 2013 Cochrane Review that focused on the quantitative effects of malaria MDA, we have conducted a systematic, qualitative review of published, unpublished, and gray literature documenting past MDA experiences. We have also consulted with field experts, using their historical experience to provide an informed, contextual perspective on the role of MDA in malaria elimination. Substantial knowledge gaps remain and more research is necessary, particularly on optimal target population size, methods to improve coverage, and primaquine safety. Despite these gaps, MDA has been used successfully to control and eliminate Plasmodium falciparum and P. vivax malaria in the past, and should be considered as part of a comprehensive malaria elimination strategy in specific settings
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