385 research outputs found

    Divergence in Eco-Physiological Responses to Drought Mirrors the Distinct Distribution of Chamerion angustifolium Cytotypes in the Himalaya–Hengduan Mountains Region

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    Polyploid species generally occupy harsher habitats (characterized by cold, drought and/or high altitude) than diploids, but the converse was observed for Chamerion angustifolium, in which diploid plants generally inhabit higher altitudes than their polyploid derivatives. Plants at high altitudes may experience cold-induced water stress, and we therefore examined the physiological responses of diploid and hexaploid C. angustifolium to water stress to better understand the ecological differentiation of plants with different ploidy levels. We conducted a common garden experiment by subjecting seedlings of different ploidy levels to low, moderate and severe water stress. Fourteen indicators of physiological fitness were measured, and the anatomical characteristics of the leaves of each cytotype were determined. Both cytotypes were influenced by drought, and diploids exhibited higher fitness in terms of constant root:shoot ratio (R:S ratio) and maximum quantum yield of PSⅡ (Fv/Fm), less reduced maximal photosynthetic rate (Amax), transpiration rate (E), intercellular CO2 concentration (Ci) and stomatal conductance (gs), and higher long-term water use efficiency (WUEL) under severe water stress than did hexaploids. Analysis of leaf anatomy revealed morphological adjustments for tolerating water deficiency in diploids, in the form of closely packed mesophyll cells and small conduits in the midvein. Our results indicate that diploid C. angustifolium is more tolerant of drought than hexaploid plants, ensuring the successful survival of the diploid at high altitudes. This eco-physiological divergence may facilitate the species with different cytotypes to colonize new and large geographic ranges with heterogeneous environmental conditions

    Transverse optical binding for a dual dipolar dielectric nanoparticle dimer

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    Funding: This work was supported by the National Key R&D Program of China (2017YFA0303400) andPostgraduate Education Reform Project of Tongji University (2018GH103). KD acknowledges support of the UK Engineering and Physical Sciences Research Council (grant EP/P030017/1).The physical origins of transverse optical binding force and torque beyond Rayleigh approximation have not been clearly expressed to date. Here, we present analytical expressions of the force and torque for a dual dipolar dielectric dimer illuminated by a plane wave propagating perpendicularly to the dimer axis. Using this analytical model, we explore the role of the hybridized electric dipolar, magnetic dipolar, and electric-magnetic dipolar coupling interactions in the total force and torque on the particles. We find significant departures from the predictions of the Rayleigh approximation, especially for high-refractive index particles, where the force is dominated by the magnetic interaction. This results in the enhancement of the dimer stability by 1 to 4 orders of magnitude compared to the predictions of the Rayleigh approximation. For the torque, this is dominated by the coupling interaction and increases by an order of magnitude. Our results will help to guide future experimental work in the light-controlled self-assembly of high-refractive-index dielectric particles.PostprintPeer reviewe

    Investigation of the morbidity of dry eye among special crowd in Shunde district

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    AIM: To investigate the morbidity of dry eye in policeman of Shunde district, and to analyze the related factors and proposed methods of preventing and treating dry eye.<p>METHODS:Totally 650 policemen who came for physical examination in Shunde district recived questionnaire survey. The patients with dye eye disease were finally diagnosed through slit lamp examination, Schirmer test, tear film break-up time(BUT)measurement and keratoconjunctival fluorescent staining. The morbidity among different policemen was further analyzed and stasticed.<p>RESULTS:The results showed that 152 in 650 policemen suffered from dry eye disease, the ratio was 23.4%. Comparied with security police and crimanl police, the ratio in traffic police, patrolman,and back office police was significantly higher. The prevalence was higher when the ages were greater than 40.<p>CONCLUSION: Unsuitable working environment, air contamination are high risk factors of dry eye disease

    Risk factors of amyotrophic lateral sclerosis: a global meta-summary

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    BackgroundThe etiology of amyotrophic lateral sclerosis (ALS) remains largely unknown. This study aimed to summarize the relationship between ALS and its genetic and non-genetic risk factors.MethodA search of relevant literature from PubMed, Embase, and Cochrane Database from inception to December 2022 was performed. Random-effects or fixed-effects models were performed by Stata MP 15.0 to pool multivariate or adjusted ratios (OR). PROSPERO registration number: CRD42022301549.Results230 eligible studies were included, of which 67 involved 22 non-genetic factors, and 163 involved genetic factors. Four aspects of non-genetic factors, including lifestyle, environmental and occupational exposures, pre-existing diseases/comorbidity and medical exposures, and others, were analyzed. Exposure to heavy metals (OR = 1.79), pesticides (OR = 1.46), solvents (OR = 1.37), previous head trauma (OR = 1.37), military service (OR = 1.29), stroke (OR = 1.26), magnetic field (OR = 1.22) and hypertension (OR = 1.04) are significant risk factors, but use of antidiabetics (OR = 0.52), high BMI (OR = 0.60 for obese and overweight vs. normal and underweight), living in urban (OR = 0.70), diabetes mellitus (OR = 0.83), and kidney disease (OR = 0.84) decrease the risk for ALS. In addition, eight common ALS-related genes were evaluated, the mutation frequencies of these genes were ranked from highest to lowest as SOD1 (2.2%), C9orf72 (2.1%), ATXN2 (1.7%), FUS (1.7%), TARDBP (0.8%), VCP (0.6%), UBQLN2(0.6%) and SQSTM1 (0.6%) in all the ALS patients.ConclusionsOur findings suggested that effective intervention for risk exposure and timely modification of lifestyle might prevent the occurrence of ALS. Genetic mutations are important risk factors for ALS and it is essential to detect genetic mutations correctly and scientifically.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=301549, identifier: CRD42022301549

    Density functional theory study on the adsorption and decomposition of the formic acid catalyzed by highly active mushroom-like Au@Pd@Pt tri-metallic nanoparticles

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    National Natural Science Foundation of China [20620130427, 20925311]; National Basic Research Program of China [2009CB930703, 2010CB923300]; Goran Gustafsson Foundation for Research in Natural Sciences and Medicine; Swedish National Infrastructure for Computing (SNIC)Local structures and adsorption energies of a formic acid molecule and its decomposed intermediates (H, O, OH, CO, HCOO, and COOH) on highly electrocatalytically active mushroom-like Au-core@Pd-shell@Pt-cluster nanoparticles with two atomic layers of the Pd shell and stoichiometric Pt coverage of around half-monolayer (Au@2 ML [email protected] ML Pt) have been investigated by first principles calculations. The adsorption sites at the center (far away from the Pt cluster) and the edge (close to the Pt cluster) are considered and compared. Significant repulsive interaction between the edge sites and CO is observed. The calculated potential energy surfaces demonstrate that, with respect to the center sites, the CO2 pathway is considerably promoted in the edge area. Our results reveal that the unique edge structure of the Pt cluster is responsible for the experimentally observed high electrocatalytic activity of the Au@Pd@Pt nanoparticles toward formic acid oxidation. Such microscopic understanding should be useful for the design of new electrochemical catalysts

    Population phylogenomic analysis of mitochondrial DNA in wild boars and domestic pigs revealed multiple domestication events in East Asia

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    A fine-grained mitochondrial DNA phylogenomic analysis was conducted in domestic pigs and wild boars, revealing that pig domestication in East Asia occurred in the Mekong and the middle and downstream regions of the Yangtze river

    Observations on Copy Number Variations in a Kidney-yang Deficiency Syndrome Family

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    We have performed an analysis of a family with kidney-yang deficiency syndrome (KDS) in order to determine the structural genomic variations through a novel approach designated as “copy number variants” (CNVs). Twelve KDS subjects and three healthy spouses from this family were included in this study. Genomic DNA samples were genotyped utilizing an Affymetrix 100 K single nucleotide polymorphism array, and CNVs were identified by Copy Number Algorithm (CNAT4.0, Affymetrix). Our results demonstrate that 447 deleted and 476 duplicated CNVs are shared among KDS subjects within the family. The homologus ratio of deleted CNVs was as high as 99.78%. One-copy-duplicated CNVs display mid-range homology. For two copies of duplicated CNVs (CNV4), a markedly heterologous ratio was observed. Therefore, with the important exception of CNV4, our data shows that CNVs shared among KDS subjects display typical Mendelian inheritance. A total of 113 genes with established functions were identified from the CNV flanks; significantly enriched genes surrounding CNVs may contribute to certain adaptive benefit. These genes could be classified into categories including: binding and transporter, cell cycle, signal transduction, biogenesis, nerve development, metabolism regulation and immune response. They can also be included into three pathways, that is, signal transduction, metabolic processes and immunological networks. Particularly, the results reported here are consistent with the extensive impairments observed in KDS patients, involving the mass-energy-information-carrying network. In conclusion, this article provides the first set of CNVs from KDS patients that will facilitate our further understanding of the genetic basis of KDS and will allow novel strategies for a rational therapy of this disease
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