1,244 research outputs found

    The Cosmic Infrared Background: Measurements and Implications

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    The cosmic infrared background records much of the radiant energy released by processes of structure formation that have occurred since the decoupling of matter and radiation following the Big Bang. In the past few years, data from the Cosmic Background Explorer mission provided the first measurements of this background, with additional constraints coming from studies of the attenuation of TeV gamma-rays. At the same time there has been rapid progress in resolving a significant fraction of this background with the deep galaxy counts at infrared wavelengths from the Infrared Space Observatory instruments and at submillimeter wavelengths from the Submillimeter Common User Bolometer Array instrument. This article reviews the measurements of the infrared background and sources contributing to it, and discusses the implications for past and present cosmic processes.Comment: 61 pages, incl. 9 figures, to be published in Annual Reviews of Astronomy and Astrophysics, 2001, Vol. 3

    Star Formation in Galaxies Along the Hubble Sequence

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    Observations of star formation rates (SFRs) in galaxies provide vital clues to the physical nature of the Hubble sequence, and are key probes of the evolutionary properties of galaxies. The focus of this review is on the broad patterns in the star formation properties of galaxies along the Hubble sequence, and their implications for understanding galaxy evolution and the physical processes that drive the evolution. Star formation in the disks and nuclear regions of galaxies are reviewed separately, then discussed within a common interpretive framework. The diagnostic methods used to measure SFRs are also reviewed, and a self-consistent set of SFR calibrations is presented as an aid to workers in the field.Comment: 41 pages, with 9 figures. To appear in Volume 36 of the Annual Review of Astronomy and Astrophysic

    B7-H1-Deficiency Enhances the Potential of Tolerogenic Dendritic Cells by Activating CD1d-Restricted Type II NKT Cells

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    Background: Dendritic cells (DC) can act tolerogenic at a semi-mature stage by induction of protective CD4+ T cell and NKT cell responses. Methodology/Principal Findings: Here we studied the role of the co-inhibitory molecule B7-H1 (PD-L1, CD274) on semimature DC that were generated from bone marrow (BM) cells of B7-H12/2 mice and applied to the model of Experimental Autoimmune Encephalomyelitis (EAE). Injections of B7-H1-deficient DC showed increased EAE protection as compared to wild type (WT)-DC. Injections of B7-H12/2 TNF-DC induced higher release of peptide-specific IL-10 and IL-13 after restimulation in vitro together with elevated serum cytokines IL-4 and IL-13 produced by NKT cells, and reduced IL-17 and IFN-c production in the CNS. Experiments in CD1d2/2 and Ja2812/2 mice as well as with type I and II NKT cell lines indicated that only type II NKT cells but not type I NKT cells (invariant NKT cells) could be stimulated by an endogenous CD1d-ligand on DC and were responsible for the increased serum cytokine production in the absence of B7-H1. Conclusions/Significance: Together, our data indicate that BM-DC express an endogenous CD1d ligand and B7-H1 to ihibit type II but not type I NKT cells. In the absence of B7-H1 on these DC their tolerogenic potential to stimulate tolerogenic CD4+ and NKT cell responses is enhanced

    A β-Lactam Antibiotic Dampens Excitotoxic Inflammatory CNS Damage in a Mouse Model of Multiple Sclerosis

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    In multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), impairment of glial “Excitatory Amino Acid Transporters” (EAATs) together with an excess glutamate-release by invading immune cells causes excitotoxic damage of the central nervous system (CNS). In order to identify pathways to dampen excitotoxic inflammatory CNS damage, we assessed the effects of a β-lactam antibiotic, ceftriaxone, reported to enhance expression of glial EAAT2, in “Myelin Oligodendrocyte Glycoprotein” (MOG)-induced EAE. Ceftriaxone profoundly ameliorated the clinical course of murine MOG-induced EAE both under preventive and therapeutic regimens. However, ceftriaxone had impact neither on EAAT2 protein expression levels in several brain areas, nor on the radioactive glutamate uptake capacity in a mixed primary glial cell-culture and the glutamate-induced uptake currents in a mammalian cell line mediated by EAAT2. Moreover, the clinical effect of ceftriaxone was preserved in the presence of the EAAT2-specific transport inhibitor, dihydrokainate, while dihydrokainate alone caused an aggravated EAE course. This demonstrates the need for sufficient glial glutamate uptake upon an excitotoxic autoimmune inflammatory challenge of the CNS and a molecular target of ceftriaxone other than the glutamate transporter. Ceftriaxone treatment indirectly hampered T cell proliferation and proinflammatory INFγ and IL17 secretion through modulation of myelin-antigen presentation by antigen-presenting cells (APCs) e.g. dendritic cells (DCs) and reduced T cell migration into the CNS in vivo. Taken together, we demonstrate, that a β-lactam antibiotic attenuates disease course and severity in a model of autoimmune CNS inflammation. The mechanisms are reduction of T cell activation by modulation of cellular antigen-presentation and impairment of antigen-specific T cell migration into the CNS rather than or modulation of central glutamate homeostasis

    Changes in the nutrient status of soil caused by cropping and fertilization in a Typic Ustochrept

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    Field experiments were conducted during 1984-1986 on an alluvial (Typic Ustochrept) soil (pH 8.0. organic carbon 0.46%) at IARI farm. New Delhi to study the changes in available soil nutrients (N, P, K, Mn, Fe. Zn and Cu) at different production levels. Fertilizer was applied to wheat followed by maize, based on the Ta rge tted yield concept’, and mustard was grown after the sequence to estimate the residual effect of nutrients. Nutrient applications for the largest yield targets ( 6 t h a -1 of wheat followed by 4 or 5 t h a -1 of maize) resulted in a comparatively greater buildup of soil nutrients (N, P and K). the greatest yield of a succeeding mustard crop, and a better soil nutrient status than that at the start of the experiment, even after the mustard. When both crops were fertilized for the largest target yield with straight fertilizers (Urea. SSP and KC1), the additions of N, P and K and of micronutrient cations (Mn, Fe. Zn and Cu) maintained a favorable balance for major and trace nutrients and provided a sound basis for profitable crop productio

    Toward a theory‐based specification of non‐pharmacological treatments in aging and dementia: Focused reviews and methodological recommendations

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    INTRODUCTION: Non-pharmacological treatments (NPTs) have the potential to improve meaningful outcomes for older people at risk of, or living with dementia, but research often lacks methodological rigor and continues to produce mixed results. METHODS: In the current position paper, experts in NPT research have specified treatment targets, aims, and ingredients using an umbrella framework, the Rehabilitation Treatment Specification System. RESULTS: Experts provided a snapshot and an authoritative summary of the evidence for different NPTs based on the best synthesis efforts, identified main gaps in knowledge and relevant barriers, and provided directions for future research. Experts in trial methodology provide best practice principles and recommendations for those working in this area, underscoring the importance of prespecified protocols. DISCUSSION: We conclude that the evidence strongly supports various NPTs in relation to their primary targets, and discuss opportunities and challenges associated with a unifying theoretical framework to guide future efforts in this area

    Psoriasin (S100A7) expression is altered during skin tumorigenesis

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    BACKGROUND: Psoriasin (S100A7) expression has previously been associated with psoriasiform hyperplasia as well as with tumor progression in breast cancer. Its expression profile for different stages of skin lesions is unknown. The aim of this study was to determine the relationship between psoriasin (S100A7) and tumor progression in skin. METHODS: Psoriasin was assessed by immunohistochemistry and levels of expression determined by semi-quantitative scoring in skin biopsies from 50 patients. The cohort included normal skin, actinic keratosis, squamous carcinoma in-situ, invasive squamous cell carcinoma, and basal cell carcinoma. RESULTS: In normal skin, psoriasin was rarely detected in epidermis but was expressed in underlying adnexae. In abnormal epidermis psoriasin was frequently expressed in abnormal keratinocytes in actinic keratosis, in-situ and invasive squamous cell carcinoma, but was rarely observed in the basal epidermal layer or in superficial or invasive basal cell carcinoma. The highest levels of expression were seen within squamous carcinoma in-situ. Significantly reduced levels of expression were observed in both unmatched (p = 0.0001) and matched (p < 0.004) invasive squamous cell carcinoma. Psoriasin expression within abnormal squamous lesions correlated with mitotic count (r = 0.54, p = 0.0036), however no significant relation was found with the intensity of dermal inflammatory cell infiltrates assessed within each pathology. CONCLUSION: These results suggest that altered psoriasin expression occurs in abnormal epidermis and that downregulation may be related to the onset of invasion in squamous cell carcinoma in skin

    Development, standardization and refinement of procedures for evaluating effects of endocrine active compounds on development and sexual differentiation of Xenopus laevis

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    Xenopus laevis has been introduced as a model to study effects of endocrine-active compounds (EAC) on development and sexual differentiation. However, variable and inconsistent data have raised questions about the reliability of the test methods applied. The current study was conducted in two laboratories to develop, refine, and standardize procedures and protocols. Larvae were exposed in flow-through systems to 17β-estradiol (E2), at concentrations from 0.2 to 6.0 μg E2 L−1 in Experiment 1A, and 0.015 to 2.0 μg E2 L−1 in Experiment 1B. In both studies survival (92%, 99%) and percentage of animals that completed metamorphosis (97%, 99%) indicated reproducible biological performance. Furthermore, minor variations in husbandry led to significant differences in snout-to-vent length, weight, and gonad size. In Experiment 1A, almost complete feminization occurred in all E2 treatment groups whereas a concentration response was observed in Experiment 1B resulting in an EC50 of 0.12 μg E2 L−1. The final verified protocol is suitable for determining effects of EAC on development and sexual differentiation in X. laevis

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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