2,721 research outputs found

    Remnants of an ancient forest provide ecological context for Early Miocene fossil apes

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    The lineage of apes and humans (Hominoidea) evolved and radiated across Afro-Arabia in the early Neogene during a time of global climatic changes and ongoing tectonic processes that formed the East African Rift. These changes probably created highly variable environments and introduced selective pressures influencing the diversification of early apes. However, interpreting the connection between environmental dynamics and adaptive evolution is hampered by difficulties in locating taxa within specific ecological contexts: time-averaged or reworked deposits may not faithfully represent individual palaeohabitats. Here we present multiproxy evidence from Early Miocene deposits on Rusinga Island, Kenya, which directly ties the early ape Proconsul to a widespread, dense, multistoried, closed-canopy tropical seasonal forest set in a warm and relatively wet, local climate. These results underscore the importance of forested environments in the evolution of early apes

    Analysis of visceral hyperalgesia in symptomatic subgroups of the "irritable bowel syndrome" : lowered bowel compliance or increased pain sensitivity?

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    Examines visceral hypersensitivity in three groups of irritable bowel syndrome (IBS) patients. It is suggested that visceral hypersensitivity, as demonstrated by a lower pain threshold to distension of the colon in IBS patients, could explain a major part of the clinical symptomatology of these patients. A total of 46 IBS patients (either diarrhea predominant, constipation predominant, or alternating diarrhea and constipation predominant) and 14 healthy controls participated in the study that compared sensation and motility responses to graded distensions of the sigmoid colon. Results supported findings from a previous study that show reduced volume thresholds of IBS patients with abdominal pain symptoms and diarrhea, but not in constipated patients and controls. This lowered colonic compliance is sufficient enough to explain visceral hypersensitivity as well as the correlated increases in elicited contractions in IBS patients. The increased pressure thresholds that were found demonstrated that these patients do not suffer from genuine hyperalgesia; rather, they experience an abnormal tonic reflex response that produces steeper pressure volume curves. Thresholds for non-nociceptive sensations exhibited the same pattern. Finally, no differences were found between groups in somatic pain sensitivity. It is concluded that reliable visceral pain tests are important for the differentiation of the IBS subgroups as well as for other syndromes with gastrointestinal pain

    Insect Cell Expression and Purification of Recombinant SARS-COV-2 Spike Proteins That Demonstrate ACE2 Binding

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    The COVID-19 pandemic caused by SARS-CoV-2 infection has led to socio-economic shutdowns and the loss of over 5 million lives worldwide. There is a need for the identification of therapeutic targets to treat COVID-19. SARS-CoV-2 spike is a target of interest for the development of therapeutic targets. We developed a robust SARS-CoV-2 S spike expression and purification protocol from insect cells and studied four recombinant SARS-CoV-2 spike protein constructs based on the original SARS-CoV-2 sequence using a baculovirus expression system: a spike protein receptor-binding domain that includes the SD1 domain (RBD) coupled to a fluorescent tag (S-RBD-eGFP), spike ectodomain coupled to a fluorescent tag (S-Ecto-eGFP), spike ectodomain with six proline mutations and a foldon domain (S-Ecto-HexaPro(+F)), and spike ectodomain with six proline mutations without the foldon domain (S-Ecto-HexaPro(-F)). We tested the yield of purified protein expressed from the insect cell lines Spodoptera frugiperda (Sf9) and Trichoplusia ni (Tni) and compared it to previous research using mammalian cell lines to determine changes in protein yield. We demonstrated quick and inexpensive production of functional glycosylated spike protein of high purity capable of recognizing and binding to the angiotensin converting enzyme 2 (ACE2) receptor. To further confirm functionality, we demonstrate binding of eGFP fused construct of the spike ectodomain (S-Ecto-eGFP) to surface ACE2 receptors on lung epithelial cells by flow cytometry analysis and show that it can be decreased by means of receptor manipulation (blockade or downregulation)

    Oxidative costs of reproduction in mouse strains selected for different levels of food intake and which differ in reproductive performance

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    We are grateful to the animal house staff for their care of the animals. This work was supported in part by the US National Institute of Health grants R01AG043972 to J.R.S. and D.B.A. and P30AG050886 and P30DK056336 to D.B.A. The opinions expressed are those of the authors and do not necessarily represent those of the N.I.H. or any other organization. A.H.A.J. was supported by an Iraqi government student scholarship.Peer reviewedPublisher PD

    Modular Robotic Vehicle

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    A modular robotic vehicle includes a chassis, driver input devices, an energy storage system (ESS), a power electronics module (PEM), modular electronic assemblies (eModules) connected to the ESS via the PEM, one or more master controllers, and various embedded controllers. Each eModule includes a drive wheel containing a propulsion-braking module, and a housing containing propulsion and braking control assemblies with respective embedded propulsion and brake controllers, and a mounting bracket covering a steering control assembly with embedded steering controllers. The master controller, which is in communication with each eModule and with the driver input devices, communicates with and independently controls each eModule, by-wire, via the embedded controllers to establish a desired operating mode. Modes may include a two-wheel, four-wheel, diamond, and omni-directional steering modes as well as a park mode. A bumper may enable docking with another vehicle, with shared control over the eModules of the vehicles
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