164 research outputs found

    Carbon-Chain Molecules in Molecular Outflows and Lupus I Region--New Producing Region and New Forming Mechanism

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    Using the new equipment of the Shanghai Tian Ma Radio Telescope, we have searched for carbon-chain molecules (CCMs) towards five outflow sources and six Lupus I starless dust cores, including one region known to be characterized by warm carbon-chain chemistry (WCCC), Lupus I-1 (IRAS 15398-3359), and one TMC-1 like cloud, Lupus I-6 (Lupus-1A). Lines of HC3N J=2-1, HC5N J=6-5, HC7N J=14-13, 15-14, 16-15 and C3S J=3-2 were detected in all the targets except in the outflow source L1660 and the starless dust core Lupus I-3/4. The column densities of nitrogen-bearing species range from 1012^{12} to 1014^{14} cm2^{-2} and those of C3_3S are about 1012^{12} cm2^{-2}. Two outflow sources, I20582+7724 and L1221, could be identified as new carbon-chain--producing regions. Four of the Lupus I dust cores are newly identified as early quiescent and dark carbon-chain--producing regions similar to Lup I-6, which together with the WCCC source, Lup I-1, indicate that carbon-chain-producing regions are popular in Lupus I which can be regard as a Taurus like molecular cloud complex in our Galaxy. The column densities of C3S are larger than those of HC7N in the three outflow sources I20582, L1221 and L1251A. Shocked carbon-chain chemistry (SCCC) is proposed to explain the abnormal high abundances of C3S compared with those of nitrogen-bearing CCMs. Gas-grain chemical models support the idea that shocks can fuel the environment of those sources with enough S+S^+ thus driving the generation of S-bearing CCMs.Comment: 7 figures, 8 tables, accepted by MNRA

    Mechanism of bending-sideslip of inclined thick bedding slope: A case study of Qingkou landslide in Wulong, Chongqing

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    The Qingkou landslide in Wulong, Chongqing, has developed on an inclined thick abrupt cliff, with a large area of goaf formed due to hundreds of years of coal mining below. Based on the analysis of the geological conditions, current goaf situation, and deformation characteristics of the mountain, it is identified that the landslide exhibits both bending-tension and sideslip deformations, suggesting a bending-sideslip failure mode. The deformation history of the mountain is examined, and the deformation characteristics of the landslide are analyzed in two stages: bending deformation and sideslipping deformation. Change in the rock surface occurrence are studied accordingly. Considering the combination relationship between bedding and the free face, the mountain failure is divided into bending-tension failure, wedge failure and plane-sliding failure. Criteria for each failure stage are established, revealing the evolution rules and formation mechanism of the bending-sideslip landslide. This study provides a scientific basis for the disaster prevention and mitigation of such landslides

    Bioactivity Determination of Native and Variant Forms of Therapeutic Interferons

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    The traditional antiviral assays for the determination of interferon potency are reported to have considerable variability between and within assays. Although several reporter gene assays based on interferon-inducible promoter activities have been reported, data from comprehensive validation studies are lacking and few studies have been conducted to analyze the variant forms of interferons, which could have undesirable clinical implications. Here, a reporter gene assay employing a HEK293 cell line stably transfected with luciferase gene under the control of interferon-stimulated response element promoter was developed and validated. The assay was found to be more sensitive, with a larger detection range than the antiviral assay. Several cytokines tested did not interfere with the test, suggesting the assay possesses a certain degree of selectivity. Moreover, the robustness of the assay was demonstrated by minimal variations in the results generated by different analysts and cell passage number (up to 52 passages). Finally, the method was employed to analyze several interferon variants (interferon-α 2a) and we found that the aggregated form has completely lost its potency; while a modest loss of bioactivity in oxidized interferon was observed (approx. 23%), the deamidated form essentially retained its activity

    An improved method to measure 12C/13C\rm ^{12}C/^{13}C and 14N/15N\rm ^{14}N/^{15}N abundance ratios: revisiting CN isotopologues in the Galactic outer disk

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    The variations of elemental abundance and their ratios along the Galactocentric radius result from the chemical evolution of the Milky Way disks. The 12C/13C\rm ^{12}C/^{13}C ratio in particular is often used as a proxy to determine other isotopic ratios, such as 16O/18O\rm ^{16}O/^{18}O and 14N/15N\rm ^{14}N/^{15}N. Measurements of 12CN\rm ^{12}CN and 13CN\rm ^{13}CN (or C15N\rm C^{15}N) -- with their optical depths corrected via their hyper-fine structure lines -- have traditionally been exploited to constrain the Galactocentric gradients of the CNO isotopic ratios. Such methods typically make several simplifying assumptions (e.g. a filling factor of unity, the Rayleigh-Jeans approximation, and the neglect of the cosmic microwave background) while adopting a single average gas phase. However, these simplifications introduce significant biases to the measured 12C/13C\rm ^{12}C/^{13}C and 14N/15N\rm ^{14}N/^{15}N. We demonstrate that exploiting the optically thin satellite lines of 12CN\rm ^{12}CN constitutes a more reliable new method to derive 12C/13C\rm ^{12}C/^{13}C and 14N/15N\rm ^{14}N/^{15}N from CN isotopologues. We apply this satellite-line method to new IRAM 30-m observations of 12CN\rm ^{12}CN, 13CN\rm ^{13}CN, and C15N\rm C^{15}N N=10N=1\to0 towards 15 metal-poor molecular clouds in the Galactic outer disk (Rgc>R_{\rm gc} > 12 kpc), supplemented by data from the literature. After updating their Galactocentric distances, we find that 12C/13C\rm ^{12}C/^{13}C and 14N/15N\rm ^{14}N/^{15}N gradients are in good agreement with those derived using independent optically thin molecular tracers, even in regions with the lowest metallicities. We therefore recommend using optically thin tracers for Galactic and extragalactic CNO isotopic measurements, which avoids the biases associated with the traditional method.Comment: 41 pages, 29 figures, accepted by MNRAS. Meeting materials related to this work at https://box.nju.edu.cn/d/5035a574e236408eab94

    Dependence of Chemical Abundance on the Cosmic Ray Ionization Rate in IC 348

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    Ions (e.g., H3+_3^+, H2_2O+^+) have been used extensively to quantify the cosmic-ray ionization rate (CRIR) in diffuse sightlines. However, measurements of CRIR in low-to-intermediate density gas environments are rare, especially when background stars are absent. In this work, we combine molecular line observations of CO, OH, CH, and HCO+^+ in the star-forming cloud IC~348, and chemical models to constrain the value of CRIR and study the response of the chemical abundances distribution. The cloud boundary is found to have an AVA_{\rm V} of approximately 4 mag. From the interior to the exterior of the cloud, the observed 13^{13}CO line intensities drop by an order of magnitude. The calculated average abundance of 12^{12}CO (assuming 12^{12}C/13^{13}C = 65) is (1.2±\pm0.9) ×\times104^{-4}, which increases by a factor of 6 from the interior to the outside regions. The average abundance of CH (3.3±\pm0.7 ×\times 108^{-8}) is in good agreement with previous findings in diffuse and translucent clouds (AVA_{\rm V} << 5 mag). However, we did not find a decline in CH abundance in regions of high extinction (AVA_{\rm V}\simeq8 mag) as previously reported in Taurus. By comparing the observed molecular abundances and chemical models, we find a decreasing trend of CRIR as AVA_{\rm V} increases. The inferred CRIR of ζcr\zeta_{cr} = (4.7±\pm1.5) ×\times 1016^{-16} s1^{-1} at low AVA_{\rm V} is consistent with H3+^+_3 measurements toward two nearby massive stars.Comment: 21 pages, 11 figures. Submitted to Ap

    Baitouweng decoction alleviates ulcerative colitis by regulating tryptophan metabolism through DOPA decarboxylase promotion

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    BackgroundBaitouweng decoction (BTW) is a classic botanical drugs formula that has been widely used clinically for the treatment of gut-related disorders in China. However, its role in ameliorating ulcerative colitis (UC) remains to be explored.PurposeThe study aimed to determine the therapeutic efficacy and potential mechanism of action of BTW on dextran sodium sulfate (DSS)-induced colitis mice.MethodsIn vivo: 3.5% DSS-induced experimental colitis mice were treated with BTW (Pulsatilla chinensis (Bunge) Regel, Phellodendron chinense C. K. Schneid, Coptis chinensis Franch and Fraxinus chinensis Roxb), kynurenine or DOPA decarboxylase (DDC) inhibitor (carbidopa). In vitro: Caco-2 cells were stimulated with TNF-α to activate inflammation and later treated with various concentrations of BTW and carbidopa. Model evaluation included body weight, disease activity index (DAI) score, colon length and histopathology. Cytokine levels were measured by flow cytometry. Protein levels were analyzed by proteomics and functionally annotated. The levels of tryptophan metabolites in mouse serum and colon were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Alcian Blue/Phosphate Acid Schiff (AB/PAS) staining, immunohistochemistry and western blot were used to assess the intestinal barrier function and detect the protein expression levels.ResultsBTW significantly reduced the DAI, ameliorated colonic injury and regulated inflammatory cytokines in DSS-induced colitis mice. The botanical drugs formula also promoted intestinal epithelial barrier repair by enhancing the expression of the tight junction (TJ) proteins. Tryptophan metabolic signaling pathway was significantly enriched in DSS-induced UC mice, and BTW decreased the level of kynurenine, increased indole metabolites. The therapeutic effect of BTW was evidently reduced when kynurenine was given to mice. Also, BTW promoted DDC protein expression and activated the aryl hydrocarbon receptor (AHR)/IL-22 signaling pathway.ConclusionBTW improves ulcerative colitis by promoting DDC expression, regulating the conversion of tryptophan metabolism from the kynurenine pathway to the indole metabolism pathway, thereby modulating tryptophan metabolism to increase indole metabolites, and activating AHR receptors to restore intestinal barrier function

    Discovery of a radio lobe in the Cloverleaf Quasar at z = 2.56

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    The fast growth of supermassive black holes and their feedback to the host galaxies play an important role in regulating the evolution of galaxies, especially in the early Universe. However, due to cosmological dimming and the limited angular resolution of most observations, it is difficult to resolve the feedback from the active galactic nuclei (AGN) to their host galaxies. Gravitational lensing, for its magnification, provides a powerful tool to spatially differentiate emission originated from AGN and host galaxy at high redshifts. Here we report a discovery of a radio lobe in a strongly lensed starburst quasar, H1413+117 or Cloverleaf at redshift z=2.56z= 2.56, based on observational data at optical, sub-millimetre, and radio wavelengths. With both parametric and non-parametric lens models and with reconstructed images on the source plane, we find a differentially lensed, kpc scaled, single-sided radio lobe, located at 1.2kpc{\sim}1.2\,\mathrm{kpc} to the north west of the host galaxy on the source plane. From the spectral energy distribution in radio bands, we find that the radio lobe has an energy turning point residing between 1.5 GHz and 8 GHz, indicating an age of 20--50 Myr. This could indicate a feedback switching of Cloverleaf quasar from the jet mode to the quasar mode

    Re-visiting the extended Schmidt law: the important role of existing stars in regulating star formation

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    We revisit the proposed extended Schmidt law (Shi et al. 2011) which points that the star formation efficiency in galaxies depends on the stellar mass surface density, by investigating spatially-resolved star formation rates (SFRs), gas masses and stellar masses of star formation regions in a vast range of galactic environments, from the outer disks of dwarf galaxies to spiral disks and to merging galaxies as well as individual molecular clouds in M33. We find that these regions are distributed in a tight power-law as Sigma_SFR ~(Sigma_star^0.5 Sigma_gas )^1.09, which is also valid for the integrated measurements of disk and merging galaxies at high-z. Interestingly, we show that star formation regions in the outer disks of dwarf galaxies with Sigma_SFR down to 10^(-5) Msun/yr/kpc^2, which are outliers of both Kennicutt-Schmidt and Silk-Elmegreen law, also follow the extended Schmidt law. Other outliers in the Kennicutt-Schmidt law, such as extremely-metal poor star-formation regions, also show significantly reduced deviations from the extended Schmidt law. These results suggest an important role for existing stars in helping to regulate star formation through the effect of their gravity on the mid-plane pressure in a wide range of galactic environments.Comment: 15 pages, 6 figures, 3 tables; ApJ in pres

    Sishen Pill and its active phytochemicals in treating inflammatory bowel disease and colon cancer: an overview

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    The incidence of inflammatory bowel disease (IBD) and the associated risk of colon cancer are increasing globally. Traditional Chinese medicine (TCM) treatment has unique advantages. The Sishen Pill, a common Chinese patented drug used to treat abdominal pain and diarrhea, consists mainly of Psoraleae Fructus, Myristicae Semen, Euodiae Fructus, and Schisandra Chinensis. Modern research has confirmed that Sishen Pill and its active secondary metabolites, such as psoralen, myristicin, evodiamine, and schisandrin, can improve intestinal inflammation and exert antitumor pharmacological effects. Common mechanisms in treating IBD and colon cancer mainly include regulating inflammation-related signaling pathways such as nuclear factor-kappa B, mitogen-activated protein kinase, phosphatidylinositol 3-kinase, NOD-like receptor heat protein domain-related protein 3, and wingless-type MMTV integration site family; NF-E2-related factor 2 and hypoxia-inducible factor 1α to inhibit oxidative stress; mitochondrial autophagy and endoplasmic reticulum stress; intestinal immune cell differentiation and function through the Janus kinase/signal transducer and activator of transcription pathway; and improving the gut microbiota and intestinal barrier. Overall, existing evidence suggests the potential of the Sishen pill to improve IBD and suppress inflammation-to-cancer transformation. However, large-scale randomized controlled clinical studies and research on the safety of these clinical applications are urgently required
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