6,221 research outputs found

    Abundances of Micrometazoans in Three Sandy Beaches in the Island Area of Western Lake Erie

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    Author Institution: Department of Biology, Union CollegeDuring August 1978 the interstitial micrometazoa of 3 beaches on Kelley's, Pelee and South Bass Islands in the western basin of Lake Erie were sampled. Representatives of the following taxa were found: Acarina, Cladocera, Copepoda, Ostracoda, Gastrotricha, Oligochaeta, Rotifera, Tardigrada and Turbellaria. The South Bass Island beach had the greatest mean density of micrometazoans (46.5/cm3), followed by the Pelee Island (14.2/cm3) and Kelley's Island (5.2/cm3) beaches. The South Bass community was numerically dominated by turbellarians, the Pelee community by rotifers and the Kelley's community by rotifers and gastrotrichs. The mean density of total fauna decreased with depth in the sand (70% in the top 1 cm) except at subsites in the wave-influenced zone at the water's edge where 60% of the fauna were found in the 2—3 cm depth fraction. The densities of most taxa were significantly affected by an interaction between position on the beach and depth in the sand. Densities of the 4 most abundant rotifer genera (Trichocerca, Lecane, Wierzjskiella and Cepbalodella) varied among beaches and as a function of position and depth. The gastrotrich genera Chaetonotus, Icbthydium and Lepidodermella exhibited strong differences in their distributional patterns, with only one genus abundant at any beach, position or depth. The tardigrades Hypsibius augusti and Hypsibius saltursus were found in low densities (combined mean of 0.5/cm3) below the waterline only on Pelee Island

    Hyperbaric Oxygen Therapy as a Sole Agent Is Not Immunosuppressant in a Highly Immunogenic Mouse Model

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    Background. Hyperbaric oxygen (HBO) therapy, which is used for many conditions, may also have immunosuppressive effects and could be used for prevention or treatment of graft-versus-host disease (GvHD). If HBO is immunosuppressant, then we hypothesize that HBO therapy will delay the T-cell mediated skin graft rejection. Methods. C57/BL6 black-coated (H2B) mice received skin graft from CBA (H2D) white-coated mice. Mice were treated with either 19 session of 240 kpa oxygen or 29 session of 300 kpa oxygen, for 90 minutes. Mice were housed either 4 per cage or separately, to prevent friction and mechanical factors that may affect graft survival. Skin grafts were assessed daily. Results. There was no difference in length of graft survival between mice that received either regimens of HBO therapy and mice that did not receive HBO therapy. Conclusions. HBO therapy, as a sole agent, did not delay skin graft rejection in a highly immunogenic mouse model

    The single cell transcriptional landscape of esophageal adenocarcinoma and its modulation by neoadjuvant chemotherapy

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    Immune checkpoint blockade has recently proven effective in subsets of patients with esophageal adenocarcinoma (EAC) but little is known regarding the EAC immune microenvironment. We determined the single cell transcriptional profile of EAC in 8 patients who were treatment-naive (n = 4) or had received neoadjuvant chemotherapy (n = 4). Analysis of 52,387 cells revealed 10 major cell subsets of tumor, immune and stromal cells. Prior to chemotherapy tumors were heavy infiltrated by T regulatory cells and exhausted effector T cells whilst plasmacytoid dendritic cells were markedly expanded. Two dominant cancer-associated fibroblast populations were also observed whilst endothelial populations were suppressed. Pathological remission following chemotherapy associated with broad reversal of immune abnormalities together with fibroblast transition and an increase in endothelial cells whilst a chemoresistant epithelial stem cell population correlated with poor response. These findings reveal features that underlie and limit the response to current immunotherapy and identify a range of novel opportunities for targeted therapy. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12943-022-01666-x

    An Introduction to the Chandra Carina Complex Project

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    The Great Nebula in Carina provides an exceptional view into the violent massive star formation and feedback that typifies giant HII regions and starburst galaxies. We have mapped the Carina star-forming complex in X-rays, using archival Chandra data and a mosaic of 20 new 60ks pointings using the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer, as a testbed for understanding recent and ongoing star formation and to probe Carina's regions of bright diffuse X-ray emission. This study has yielded a catalog of properties of >14,000 X-ray point sources; >9800 of them have multiwavelength counterparts. Using Chandra's unsurpassed X-ray spatial resolution, we have separated these point sources from the extensive, spatially-complex diffuse emission that pervades the region; X-ray properties of this diffuse emission suggest that it traces feedback from Carina's massive stars. In this introductory paper, we motivate the survey design, describe the Chandra observations, and present some simple results, providing a foundation for the 15 papers that follow in this Special Issue and that present detailed catalogs, methods, and science results.Comment: Accepted for the ApJS Special Issue on the Chandra Carina Complex Project (CCCP), scheduled for publication in May 2011. All 16 CCCP Special Issue papers are available at http://cochise.astro.psu.edu/Carina_public/special_issue.html through 2011 at least. 43 pages; 18 figure

    Modelling chemistry in the nocturnal boundary layer above tropical rainforest and a generalised effective nocturnal ozone deposition velocity for sub-ppbv NOx conditions

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    Measurements of atmospheric composition have been made over a remote rainforest landscape. A box model has previously been demonstrated to model the observed daytime chemistry well. However the box model is unable to explain the nocturnal measurements of relatively high [NO] and [O3], but relatively low observed [NO2]. It is shown that a one-dimensional (1-D) column model with simple O3 -NOx chemistry and a simple representation of vertical transport is able to explain the observed nocturnal concentrations and predict the likely vertical profiles of these species in the nocturnal boundary layer (NBL). Concentrations of tracers carried over from the end of the night can affect the atmospheric chemistry of the following day. To ascertain the anomaly introduced by using the box model to represent the NBL, vertically-averaged NBL concentrations at the end of the night are compared between the 1-D model and the box model. It is found that, under low to medium [NOx] conditions (NOx <1 ppbv), a simple parametrisation can be used to modify the box model deposition velocity of ozone, in order to achieve good agreement between the box and 1-D models for these end-of-night concentrations of NOx and O3. This parametrisation would could also be used in global climate-chemistry models with limited vertical resolution near the surface. Box-model results for the following day differ significantly if this effective nocturnal deposition velocity for ozone is implemented; for instance, there is a 9% increase in the following day’s peak ozone concentration. However under medium to high [NOx] conditions (NOx > 1 ppbv), the effect on the chemistry due to the vertical distribution of the species means no box model can adequately represent chemistry in the NBL without modifying reaction rate constants
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