68 research outputs found

    Metal-Enriched Neutral Gas Reservoir around a Strongly-lensed, Low-mass Galaxy at z=4z=4 Identified by JWST/NIRISS and VLT/MUSE

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    Direct observations of low-mass, low-metallicity galaxies at z4z\gtrsim4 provide an indispensable opportunity for detailed inspection of the ionization radiation, gas flow, and metal enrichment in sources similar to those that reionized the Universe. Combining the James Webb Space Telescope (JWST), VLT/MUSE, and ALMA, we present detailed observations of a strongly lensed, low-mass (107.6\approx 10^{7.6} M{\rm M}_\odot) galaxy at z=3.98z=3.98 (also see Vanzella et al. 2022). We identify strong narrow nebular emission, including CIV λλ1548,1550\lambda\lambda1548,1550, HeII λ1640\lambda1640, OIII] λλ1661,1666\lambda\lambda1661,1666, [NeIII] λ3868\lambda3868, [OII] λ3727\lambda3727, and Balmer series of Hydrogen from this galaxy, indicating a metal-poor HII region (0.12 Z\lesssim 0.12\ {\rm Z}_\odot) powered by massive stars. Further, we detect a metal-enriched damped Lyα\alpha system (DLA) associated with the galaxy with the HI column density of NHI1021.8N_{\rm{HI}}\approx 10^{21.8} cm2^{-2}. The metallicity of the associated DLA may reach the super solar metallicity (Z{\gtrsim Z}_\odot). Moreover, thanks to JWST and gravitational lensing, we present the resolved UV slope (β\beta) map at the spatial resolution of 100\approx 100 pc at z=4z=4, with steep UV slopes reaching β2.5\beta \approx -2.5 around three star-forming clumps. Combining with low-redshift analogs, our observations suggest that low-mass, low-metallicity galaxies, which dominate reionization, could be surrounded by a high covering fraction of the metal-enriched, neutral-gaseous clouds. This implies that the metal enrichment of low-mass galaxies is highly efficient, and further support that in low-mass galaxies, only a small fraction of ionizing radiation can escape through the interstellar or circumgalactic channels with low column-density neutral gas.Comment: 4 pages, 1 table; submitted to the ApJL; welcome comment

    Changing Urban Form and Transport CO2 Emissions: An Empirical Analysis of Beijing, China

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    Decentralization development and changing urban form will increase the mobility and contribute to global CO2 emissions, in particular for developing countries which are experiencing rapid economic growth and urban expansion. In this paper, an integrated analytical framework, which can quantify the impact of changing urban form on commuting CO2 emissions, is presented. This framework simultaneously considers two emission dependent factors, commuting demand and modal share based on the concept of excess commuting and accessibility analysis, and ensures its applicability to other cities where the detailed individual travel data is not available. A case study of Beijing from 2000 to 2009 is used to illustrate this framework. The findings suggest that changing urban form in Beijing did have a significant impact on commuting CO2 emission increase. Changing to a more decentralized urban form in Beijing had a larger impact on commuting distance and increased usage of cars, which resulted in a significant rise in CO2 emissions. There is a larger space and an urgent need for commuting CO2 emission reduction, in 2009 in Beijing, by planning and by strategic measures in order to promote sustainable transport

    A Method for Screening Climate Change-Sensitive Infectious Diseases

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    Climate change is a significant and emerging threat to human health, especially where infectious diseases are involved. Because of the complex interactions between climate variables and infectious disease components (i.e., pathogen, host and transmission environment), systematically and quantitatively screening for infectious diseases that are sensitive to climate change is still a challenge. To address this challenge, we propose a new statistical indicator, Relative Sensitivity, to identify the difference between the sensitivity of the infectious disease to climate variables for two different climate statuses (i.e., historical climate and present climate) in non-exposure and exposure groups. The case study in Anhui Province, China has demonstrated the effectiveness of this Relative Sensitivity indicator. The application results indicate significant sensitivity of many epidemic infectious diseases to climate change in the form of changing climatic variables, such as temperature, precipitation and absolute humidity. As novel evidence, this research shows that absolute humidity has a critical influence on many observed infectious diseases in Anhui Province, including dysentery, hand, foot and mouth disease, hepatitis A, hemorrhagic fever, typhoid fever, malaria, meningitis, influenza and schistosomiasis. Moreover, some infectious diseases are more sensitive to climate change in rural areas than in urban areas. This insight provides guidance for future health inputs that consider spatial variability in response to climate change

    Molecular and Structural Evolution of Porcine Epidemic Diarrhea Virus

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    To analyze the evolutionary characteristics of the highly contagious porcine epidemic diarrhea virus (PEDV) at the molecular and structural levels, we analyzed the complete genomes of 647 strains retrieved from the GenBank database. The results showed that the spike (S) gene exhibited larger dS (synonymous substitutions per synonymous site) values than other PEDV genes. In the selective pressure analysis, eight amino acid (aa) sites of the S protein showed strong signals of positive selection, and seven of them were located on the surface of the S protein (S1 domain), suggesting a high selection pressure of S protein. Topologically, the S gene is more representative of the evolutionary relationship at the genome-wide level than are other genes. Structurally, the evolutionary pattern is highly S1 domain-related. The haplotype networks of the S gene showed that the strains are obviously clustered geographically in the lineages corresponding to genotypes GI and GII. The alignment analysis on representative strains of the main haplotypes revealed three distinguishable nucleic acid sites among those strains, suggesting a putative evolutionary mechanism in PEDV. These findings provide several new fundamental insights into the evolution of PEDV and guidance for developing effective prevention countermeasures against PEDV

    Severity of functional tricuspid regurgitation is associated with mortality in patients with pulmonary hypertension in long‐term follow‐up

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    Abstract Pulmonary hypertension (PH) is a hemodynamic and pathophysiologic state present in many cardiovascular, respiratory, and systemic diseases. PH is considered to have a higher risk of cardiovascular events and mortality. The most common type of functional tricuspid regurgitation (FTR) is associated with PH. The aim of this study was to evaluate the association between FTR severity and mortality in PH in western China. This is a retrospective analysis in PH patients and all patients underwent right‐heart catheterization (RHC) for hemodynamic measurements. The FTR severity was determined according to the guidelines. Uni‐ and multivariate analyses were used to identify risk factors for mortality. From 2015 to 2021, 136 patients with PH with a median age of 50 years (interquartile range [IQR]: 35–64 years). During 26‐month median follow‐up (mean 27.7 ± 15.1 months), 40 (29.2%) patients died (mean after 21.7 ± 14.1 months). In the univariate Cox regression analysis, World Health Organization functional class (WHO FC) III/IV, elevated B‐type natriuretic peptide, pulmonary vascular resistance (≥16.2 Wood units), pulmonary artery oxygen saturation, severe FTR and right ventricular diameter/left ventricular diameter (≥0.62) were significantly associated with mortality. In the multivariate Cox regression analysis, severe FTR, WHO FC III/IV, and right ventricular end‐diastolic pressure (RVEDP) were risk factors for mortality. Severe FTR at baseline was strongly associated with mortality in both precapillary and postcapillary PH patients, independent of the other risk factors as RVEDP, HO FC III/IV, optimal pulmonary arterial hypertension targeted therapy

    Total Burden of Cerebral Small Vessel Disease on MRI May Predict Cognitive Impairment in Parkinson’s Disease

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    (1) Objective: to investigate the association between the total burden of cerebral small vessel disease (CSVD) and cognitive function in Parkinson’s disease (PD). (2) Methods: this retrospective study compared clinical and neuroimaging characteristics of 122 PD patients to determine the association between cognitive decline and total burden of CSVD in PD. All patients underwent brain MRI examinations, and their total CSVD burden scores were evaluated by silent lacunar infarction (SLI), cerebral microbleeds (CMB), white matter hyperintensities (WMH), and enlarged perivascular spaces (EPVS). The cognitive function was assessed by administering Mini-Mental State Examination (MMSE). Receiver-operating characteristic (ROC) curve and the area under the ROC curve (AUC) were performed to quantify the accuracy of the total burden of CSVD and PVH in discriminating PD patients with or without cognitive impairment. (3) Results: the PD patients with cognitive impairment had a significantly higher SLI, CMB, periventricular hyperintensities (PVH), deep white matter hyperintensities (DWMH), enlarged perivascular spaces of basal ganglia (BG-EPVS), and the total CSVD score compared with no cognitive impairment. Total CSVD score and MMSE had a significant negative correlation (r = −0. 483). Furthermore, total burden of CSVD and PVH were the independent risk factors of cognitive impairment in PD, and their good accuracy in discriminating PD patients with cognitive impairment from those with no cognitive impairment was confirmed by the results of ROC curves. (4) Conclusions: total burden of CSVD tightly linked to cognitive impairment in PD patients. The total burden of CSVD or PVH may predict the cognitive impairment in PD

    Map of Enteropathogenic Escherichia coli Targets Mitochondria and Triggers DRP-1-Mediated Mitochondrial Fission and Cell Apoptosis in Bovine Mastitis

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    Bovine mastitis seriously affects bovine health and dairy product quality. Escherichia coli is the most important pathogen in the environment and dairy products. Enteropathogenic Escherichia coli (EPEC) is a zoonotic pathogen, which seriously threatens the health of people and dairy cows. We recently reported that E. coli can induce endogenous apoptosis in bovine mammary epithelial cells. However, the mechanism of EPEC-damaged mitochondria and -induced bovine mastitis is unclear. In this study, we found that EPEC can induce DRP-1-dependent mitochondrial fission and apoptosis. This was verified by the application of Mdivi, a DRP-1 inhibitor. Meanwhile, in order to verify the role of the Map virulence factor in EPEC-induced bovine mastitis, we constructed a map mutant, complementary strain, and recombinant plasmid MapHis. In the present study, we find that Map induced DRP-1-mediated mitochondrial fission, resulting in mitochondrial dysfunction and apoptosis. These inferences were further verified in vivo by establishing a mouse mastitis model. After the map gene was knocked out, breast inflammation and apoptosis in mice were significantly alleviated. All results show that EPEC targets mitochondria by secreting the Map virulence factor to induce DRP-1-mediated mitochondrial fission, mitochondrial dysfunction, and endogenous apoptosis in bovine mastitis

    Roles of BDNF, dopamine D-3 receptors, and their interactions in the expression of morphine-induced context-specific locomotor sensitization

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    Drug seeking, craving, and relapse can be triggered by environmental stimuli that acquire motivational salience through repeated associations with the drug&#39;s effects. Previous studies indicated that the dopamine D-3 receptor (Drd3) might be involved in the expression of drug-conditioned responses in rats, and brain-derived neurotrophic factor (BDNF) could modulate Drd3 expression in the nucleus accumbens (NAc). However, the involvement of neural regions with Drd3 activation and the underlying interaction between BDNF and Drd3 in the expression of behavioral responses controlled by a drug-associated environment have remained poorly understood. The present study used a conditioning procedure to assess the roles of BDNF, Drd3, and their interactions in the NAc in the expression of morphine-induced context-specific locomotor sensitization. We showed that the expression of locomotor sensitization in the morphine-paired environment was accompanied by significantly increased expression of Drd3 mRNA and BDNF mRNA and protein levels. Both sensitized locomotion in morphine-paired rats and enhanced Drd3 mRNA were suppressed by intra-NAc infusion of anti-tyrosine kinase receptor B (TrkB) IgG. Furthermore, intra-NAc infusion of the Drd3-selective antagonist SB-277011A significantly decreased the expression of context-specific locomotor sensitization and upregulated BDNF mRNA. Altogether, these results suggest that BDNF/TrkB signaling and activation of Drd3 in the NAc are required for the expression of morphine-induced context-specific locomotor sensitization. (C) 2011 Elsevier B.V. and ECNP. All rights reserved.</p
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