4,053 research outputs found

    Distribution of the extensive Doppler redshift of quasars

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    We make an analysis of the distribution of the extensive Doppler redshift defined as z~Dopp=(zabszem)/(1+zem)\widetilde{z}_{Dopp}=(z_{abs}-z_{em})/(1+z_{em}) with a sample of 1317 absorption redshifts available from 401 quasars. The analysis reveals a bi-peak structure in the distribution, with one component located at z~Dopp0.00\widetilde{z}_{Dopp}\simeq 0.00 and the other at z~Dopp0.01\widetilde{z}% _{Dopp}\simeq -0.01. A study of some possible causes suggests that the structure can be well interpreted: while the absorbers inside the same cluster as the quasar concerned could contribute to the first component and the less populated space between clusters could explain the gap between the two peaks, the typical distance between clusters could account for the second component. If the bi-peak structure is true, which needs to be confirmed by complete samples, one would be able to obtain some useful cosmological information.Comment: 13 pages, 8 figure

    Age-Related Thymic Atrophy: Mechanisms and Outcomes

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    Age-related thymic atrophy or involution, a hallmark of thymic aging, takes place both in humans and animals. In this chapter, we will discuss age-related thymic atrophy, outlining the underlying cellular and molecular mechanisms of its occurrence. We will also address the downstream influences on the aged T cell immune system, not only regarding insufficiency against pathogens, but also hyper-reactivity to self. Particularly, we will focus on how thymic atrophy disrupts efficient establishment of central T cell immune tolerance primarily via impairment of thymocyte negative selection, resulting in an increased number of self-reactive conventional T cells, and on thymic-derived regulatory T cell generation. Finally, we will provide a framework for understanding the significant role that the atrophied thymus plays in shaping inflammaging: a chronic, low-grade, systemic inflammatory phenotype observed in aged individuals in the absence of acute infection. The involvement of T cell adaptive immunity in mediating inflammaging plays a crucial role in the progression of many age-related neurological and cardiovascular diseases

    Stage-specific changes in fetal thymocyte proliferation during the CD4(-)8(-) to CD4(+)8(+) transition in wild type, Rag1(-/-), and Hoxa3,Pax1 mutant mice

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    BACKGROUND: The function of the thymic microenvironment is to promote thymocyte maturation, in part via regulation of thymocyte proliferation and cell death. Defects in fetal thymic epithelial cell (TEC) development and function, and therefore in the formation of a functional microenvironment, can be caused either directly by TEC differentiation defects or indirectly by defective thymocyte maturation. In this paper we studied fetal thymocyte proliferation during the early transition from the CD3(-)4(-)8(-) (triple negative, TN) to CD4(+)8(+) (double positive, DP) stages. We compared wild type mice with Rag1(-/-) mice and with Hoxa3(+/-)Pax1(-/-) compound mutant mice, which have blocks at different stages of thymocyte development. RESULTS: Wild type fetal and adult thymus showed stage-specific differences in the proliferation profiles of developing thymocytes, with fetal stages showing generally higher levels of proliferation. The proliferation profile of fetal thymocytes from Rag1(-/-) mutants also had stage-specific increases in proliferation compared to wild type fetal thymocytes, in contrast to the lower proliferation previously reported for thymocytes from adult Rag1(-/-) mutants. We have previously shown that Hoxa3(+/-)Pax1(-/-) mice have abnormal fetal TEC development, resulting in increased apoptosis at the TN to DP transition and decreased DP cell numbers. Fetal thymocytes from Hoxa3(+/-)Pax1(-/-) compound mutants had increased proliferation, but fewer proliferating cells, at the DP stage. We also observed a decrease in the level of the cytokines IL-7 and SCF produced by Hoxa3(+/-)Pax1(-/-)TECs. CONCLUSION: Our results indicate complex and stage-specific effects of abnormal TEC development on thymocyte proliferation

    Concept for a Future Super Proton-Proton Collider

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    Following the discovery of the Higgs boson at LHC, new large colliders are being studied by the international high-energy community to explore Higgs physics in detail and new physics beyond the Standard Model. In China, a two-stage circular collider project CEPC-SPPC is proposed, with the first stage CEPC (Circular Electron Positron Collier, a so-called Higgs factory) focused on Higgs physics, and the second stage SPPC (Super Proton-Proton Collider) focused on new physics beyond the Standard Model. This paper discusses this second stage.Comment: 34 pages, 8 figures, 5 table

    Tie-dye technique and pattern features

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    Relationship between tie-dye technique and image pattern has been studied. Based on digital image processing, average value of HSV (hue, saturation, value) tri-component of valid tie-dye area, proportion of incompletely dyed area in HSV color space and the Tamura first three texture features of digital tie-dye image have been extracted. Then, the repeated tests and analysis of variance (ANOVA) of rotation speed and concentration have been done. The results show the obvious impact of concentration and rotation speed on the color and texture feature of tie-dye pattern. Furthermore, back propagation neutral network is developed and partial pattern features with low correlation is used to forecast the tie-dye concentration and rotation speed. The experiment results show the 100% rate of forecast, which proves that pattern features can effectively achieve the technique forecast

    Beneficial Effects of Anisodamine in Shock Involved Cholinergic Anti-Inflammatory Pathway

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    Anisodamine, an antagonist of muscarinic receptor, has been used therapeutically to improve blood flow in circulatory disorders such as septic shock in China since 1965. The main mechanism of anisodamine for anti-shock proposed in Pharmacology for Chinese medical students is to improve blood flow in the microcirculation. Here, we suggest a new mechanism for its anti-shock effect. That is, anisodamine, by blocking muscarinic receptor, results in rerouting of acetylcholine to α7 nicotinic acetylcholine receptor (α7nAChR) bringing about increased acetylcholine-mediated activation of α7nAChR and the cholinergic anti-inflammatory pathway
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