检索结果-南通市图书馆

Radiation Medicine and Protection 2024年第1期5卷 11-15页

作者： jing chen United Nations Scientific Committee on the Effects of Atomic Radiation Vienna International CentreP.O.Box 5001400ViennaAustria

The annex D of the United Nations Scientific Committee on the Effects of Atomic Radiation(UNSCEAR)2020/2021 Report presented a comprehensive global estimate of occupational exposure to ionizing *** worldwide annual number of workers exposed to natural and human-made sources of ionizing radiation was estimated to be approximately 24 million in the period *** 52% of those were employed in the sectors that involve exposure to natural sources of *** worldwide average annual effective dose for all workers during the period 2010-2014 was estimated to be around 1.2 mSv-about two thirds of the value estimated for the period *** annual effective dose was estimated to be around 2.0 mSv for workers exposed to natural sources and 0.5 mSv for workers exposed to human-made *** overriding limitation of current evaluation was the low rate of participation by United Nations Member States in providing occupational exposure monitoring data,especially data from non-nuclear sectors and occupational sectors involving naturally occurring radioactive *** the assessment of the worldwide occupational exposure is a complex task,the Committee relies on the collection of up-to-date data on occupational exposure from United Nations Member States in a broad range of occupational sectors,and continues collaboration with international organizations.

关键词： Occupational exposure Ionizing radiation United Nations Scientific Committee on the Effects of Atomic Radiation

The Use of Zein and Shuanghuangbu for Periodontal Tissue Engineering

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Oral Science 2010年第3期2卷 142-148页

作者： Yan-zhi Xu jing-jing wu Yan-ping chen Jian Liu Na Li Feng-ying Yang Department of Stomatology the Fourth Hospital of Hebei Medical University Shijiazhuang China

Aim Tissue engineering is a promising area with a broad range of applications in the fields of regenerative medicine and human health. The emergence of periodontal tissue engineering for clinical treatment of periodontal disease has opened a new therapeutic avenue. The choice of scaffold is crucial. This study was conducted to prepare zein scaffold and explore the suitability of zein and Shuanghuangbu for periodontal tissue *** A zein scaffold was made using the solvent casting/particulate leaching method with sodium chloride （NaC1） particles as the porogen. The physical properties of the zein scaffold were evaluated by observing its shape and determining its pore structure and porosity. Cytotoxicity testing of the scaffold was carried out via in vitro cell culture experiments, including a liquid extraction experi- ment and the direct contact assay. Also, the Chinese medicine Shuanghuangbu, as a growth factor, was diluted by scaffold extract into different concentrations. This Shuanghuangbu-scaffold extract was then added to periodontal ligament cells （PDLCs） in order to determineits effect on cell proliferation. Results The zein scaffold displayed a sponge-like structure with a high porosity and sufficient thickness. The porosity and pore size of the zein scaffold can be controlled by changing the porogen particles dosage and size. The porosity was up to 64.1%-78.0%. The pores were well-distributed, interconnected, and porous. The toxicity of the zein scaffold was graded as 0-1. Furthermore, PDLCs displayed full stretching and vigorous growth under scanning electronic microscope （SEM）. Shuanghuangbu-scaffold extract could reinforce proliferation activity of PDLCs compared to the control group, especially at 100 μ***^-1 （P〈0.01）. Conclusion A zein scaffold with high porosity, open pore wall structure, and good biocompatibility is conducive to the growth of PDLCs. Zein could be used as scaffold to repair periodontal tissue defects. Also, Shuanghu

关键词： zein periodontal tissue engineering scaffold,periodontal ligament cells Shuanghuangbu

Introduction of rare-earth element Sc in alloy design to modify wear features of dual-phase high-entropy alloy

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第2期43卷 817-828页

作者： Hao Ren Rui-Run chen Xue-Feng Gao Tong Liu Gang Qin Yu-Lung Chiu Shi-Ping wu jing-Jie Guo Guo National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin150001China School of Metallurgy and Materials University of BirminghamBirminghamB152TTUK

Tailoring the alloy composition,which induces the hard secondary phase to increase hardness and strength to improve the wear features,is a feasible approach for developing wear-resistant metal ***,a group of(AlCoCrFeNi)_(100–x)Sc_(x)(x=0–2.0,at%)high-entropy alloys(HEAs)are designed and the phase compositions and wear behaviors are ***-doped HEA series contain the primary body-centered cubic(BCC)and eutectic phases,in which the eutectic phase is composed of the alternately grown BCC and Laves *** addition promotes the diffusion of Ni atoms from BCC phase to form the Sc-rich Laves phase at the grain *** hardness increases due to solid solution strengthening and second phase *** the second phase strengthening plays a more significant role relative to solid solution *** phase and the oxides caused by wear heating prevent the direct contact between friction pair and HEAs,thus inducing a decreased wear rate from 6.82×10^(−5) to 3.47×10^(−5)m^(3)·N^(−1)·m^(−1).Moreover,the wear mechanism changes from adhesive wear,abrasive wear and oxidative wear to abrasive wear and oxidative wear.

关键词： High entropy alloy(HEA) Laves phase Hardness Wear mechanism

A Hf-doped dual-phase high-entropy alloy: phase evolution and wear features

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第1期43卷 324-333页

作者： Hao Ren Rui-Run chen Xue-Feng Gao Tong Liu Gang Qin Yu-Lung Chiu Shi-Ping wu jing-Jie Guo National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China School of Metallurgy and Materials University of BirminghamEdgbastonBirmingham B152TTUK

Initially defined high entropy alloys(HEAs)usually exhibit a single-phase solid-solution ***,two and/or more types of phases in HE As possibly induce the desired microstructure features,which contribute to improving the wear properties of HE ***,we prepare a series of(AlCoCrFeNi)_(100-x)Hf_(x)(x=0,2,4and 6;at%) HEAs and concern their phase compositions,micro structures and wear *** leads to the formation of(Ni,Co)_(2)Hf-type Laves phase and tailors the microstructure from a body-centered cubic(BCC) singlephase structure to a hypoeutectic *** increased hardness from~HV 512.3 to~HV 734.1 is due to solid-solution strengthening,grain refinement strengthening and precipitated phase *** a few oxides(Al_(2)O_(3)+Cr_(2)O_(3)) caused by the wear heating contribute to an 85.5% decrease in wear rate of the HEA system from6.71×10^(-5) to 0.97×10^(-5) m^(3)·N^(-1)·m^(-1).In addition,Hf addition changes the wear mechanism from abrasive wear,mild oxidative wear and adhesive wear to oxidative wear and adhesive wear.

关键词： High entropy alloy Laves phase Hardness Wear mechanism

Bias distribution and regulation in photoelectrochemical overall water-splitting cells

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第4期11卷 141-150页

作者： Kun Dang Siqin Liu Lei wu Daojian Tang jing Xue Jiaming Wang Hongwei Ji Chuncheng chen Yuchao Zhang Jincai Zhao Key Laboratory of Photochemistry CAS ResearchEducation Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

The water oxidation half-reaction at anodes is always considered the rate-limiting step of overall water splitting（OWS）,but the actual bias distribution between photoanodes and cathodes of photoelectro chemical（PEC） OWS cells has not been investigated *** this work,we find that,for PEC cells consisting of photoanodes（nickel-modified n-Si [Ni/n-Si] and α-Fe2O3） with low photovoltage(Vph 1V,the bias required for cathode activation can be significantly reduced,exhibiting a kinetics-controlled *** investigations show that the bias distribution can be regulated by tuning the electrolyte pH and using alternative half-reaction ***,a volcano plot is presented for the rational design of the overall reactions and unbiased PEC *** by this,an unbiased PEC cell consisting of a simple Ni/n-Si photoanode and Pt cathode is assembled,delivering a photo current density of 5.3±0.2 mA cm-2.

关键词： photoelectrochemistry overall reaction cell bias distribution photoanode water splitting

Total Synthesis of Laurane and Guaiane Sesquiterpenoids via Oxidative Nazarov Reaction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第11期42卷 1267-1274页

作者： Yuye chen Wenqing chen Zhiting Zhang jing Xu Shenzhen Grubbs Institute and Department of Chemistry and Guangming Advanced Research Institute and Guangdong Provincial Key Laboratory of Catalysis and Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis Southern University of Science and TechnologyShenzhenGuangdong518055 China

As one of the most common structural motifs in natural products,cyclopentenones usually can be fabricated by Nazarov cyclization using divinyl ketones or functionalized tertiary divinyl carbinols(TDCs)as ***,straightforward method for transforming unfunctionalized TDCs to their corresponding cyclopentenones is currently ***,we wish to report the total syntheses of four structurally distinct terpenoids,namely laurane-type marine sesquiterpenoids isolaurene,debromoaplysin and aplysin,and guaiane sesquiterpenoid guaiadienone A,all using a novel synthetic method,named oxidative Nazarov cyclization,as the key *** work demonstrated our robust method is suitable for synthesizing various highly substituted cyclopentenones.

关键词： Total synthesis Synthetic methods Sesquiterpenoids Oxidative Nazarov reaction Electrocyclization Oxoammonium salt Pericyclic reaction Annulation

Parametric resonance of axially functionally graded pipes conveying pulsating fluid

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 239-260页

作者： Jie jing Xiaoye MAO Hu DING Liqun chen Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

Based on the generalized Hamilton's principle,the nonlinear governing equation of an axially functionally graded(AFG)pipe is *** non-trivial equilibrium configuration is superposed by the modal functions of a simply supported *** the direct multi-scale method,the response and stability boundary to the pulsating fluid velocity are solved analytically and verified by the differential quadrature element method(DQEM).The influence of Young's modulus gradient on the parametric resonance is investigated in the subcritical and supercritical *** general,the pipe in the supercritical region is more sensitive to the pulsating *** nonlinearity changes from hard to soft,and the non-trivial equilibrium configuration introduces more frequency components to the ***,the increasing Young's modulus gradient improves the critical pulsating flow velocity of the parametric resonance,and further enhances the stability of the *** addition,when the temperature increases along the axial direction,reducing the gradient parameter can enhance the response *** work further complements the theoretical analysis of pipes conveying pulsating fluid.

关键词： pipe conveying fluid axially functionally graded supercritical resonance multi-scale method parametric resonance

Prevalence and clinical impact of sarcopenia in liver transplant recipients:A meta-analysis

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第8期30卷 956-968页

作者： Min-Jie Jiang Mu-chen wu Zhong-Hui Duan jing wu Xiao-Tong Xu Juan Li Qing-Hua Meng Department of Hepatology Beijing You-An HospitalCapital Medical UniversityBeijing 100069China Department of Emergency Beijing You-An HospitalCapital Medical UniversityBeijing 100069China

BACKGROUND The prevalence of sarcopenia in patients undergoing liver transplantation(LT)remains to be determined partly because of different diagnostic *** has recently been recognized as a new prognostic factor for predicting outcomes in LT *** To estimate the prevalence of sarcopenia and evaluate its clinical effect on LT *** This systematic search was conducted in PubMed,Web of Science,Embase,and Cochrane Library for original English-language articles that investigated the prevalence and influence of sarcopenia in patients undergoing LT from database inception to November 30,*** studies of the definition of sarcopenia that estimate sarcopenia prevalence and evaluate its effect on clinical outcomes and the risk of mortality were *** Twenty-five studies involving 7760 patients undergoing LT were *** pooled prevalence of sarcopenia in patients undergoing LT was 40.7%[95%confidence intervals(95%CI):32.1-49.6].The 1-,3-,and 5-year cumulative probab-ilities of post-LT survival in patients with preoperative sarcopenia were all lower than those without sarcopenia(P<0.05).Sarcopenia was associated with an increased risk of post-LT mortality in patients undergoing LT(adjusted hazard ratio:1.58;95%CI:1.21-2.07).Patients with preoperative sarcopenia had a longer intensive care unit stay,a high risk ratio of sepsis,and serious post-LT complications than those without *** Sarcopenia is prevalent in a substantial proportion of patients undergoing LT and is strongly and independently associated with higher a risk of mortality risk.

关键词： Sarcopenia Liver transplantation Mortality Clinical outcomes

Small nucleolar RNA and its potential role in the oncogenesis and development of colorectal cancer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第2期30卷 115-127页

作者： Yang-Zheng Lan Zheng wu Wen-Jia chen Ze-Xuan Fang Xin-Ning Yu Hua-Tao wu jing Liu The Breast Center Cancer Hospital of Shantou University Medical CollegeShantou 515041Guangdong ProvinceChina Department of General Surgery The First Affiliated Hospital of Shantou University Medical CollegeShantou 515041Guangdong ProvinceChina

Small nucleolar RNAs(snoRNAs)represent a class of non-coding RNAs that play pivotal roles in post-transcriptional RNA processing and modification,thereby contributing significantly to the maintenance of cellular functions related to protein *** have been discovered to possess the ability to influence cell fate and alter disease progression,holding immense potential in controlling human *** is suggested that the dysregulation of snoRNAs in cancer exhibits differential expression across various cancer types,stages,metastasis,treatment response and/or prognosis in *** the other hand,colorectal cancer(CRC),a prevalent malignancy of the digestive system,is characterized by high incidence and mortality rates,ranking as the third most common cancer *** research indicates that snoRNA dysregulation is associated with CRC,as snoRNA expression significantly differs between normal and cancerous ***,assessing snoRNA expression level and function holds promise for the prognosis and diagnosis of ***,current comprehension of the potential roles of snoRNAs in CRC remains *** review offers a comprehensive survey of the aberrant regulation of snoRNAs in CRC,providing valuable insights into the discovery of novel biomarkers,therapeutic targets,and potential tools for the diagnosis and treatment of CRC and furnishing critical cues for advancing research into CRC and the judicious selection of therapeutic targets.

关键词： Small nucleolar RNAs Colorectal cancer Dysregulation Biomarker

Study on the mechanism and reaction characteristics of metal-supported phosphogypsum as oxygen carrier in a chemical looping gasification application

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第4期138卷 428-438页

作者： jing Yang Yujie Ren Shuoyu chen Jinsuo Lu School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

This study aimed to explore the chemical looping gasification(CLG)reaction characteristics of the metal-supported composite phosphogypsum(PG)oxygen carriers(OCs)and the thermodynamic *** FactSage 7.1 thermodynamic simulation was used to explore the oxygen release and H_(2)S removal *** experimental results showed that the syngas yield of CLG with PG-CuFe_(2)O_(4)was more than that with PG-Fe_(2)O_(3)20/CuO40 or PG-Fe_(2)O_(3)30/CuO30 OC at 1023 K when the water vapor content was ***,the maximum syngas yield of the CO selectivity was 70.3% and of the CO_(2)selectivity was 23.8%.The H_(2)/CO value was 0.78,and the highest carbon conversion efficiency was 91.9% in PG-CuFe_(2)O_(4)at the gasification temperature of 1073 *** metal-supported PG composite oxygen carrier was proved not only as an oxygen carrier to participate in the preparation of syngas but also as a catalyst to catalyze coal gasification ***,both the experimental results and FactSage 7.1 thermodynamic analysis revealed that the trapping mechanism of H_(2)S by composite OCs was as follows:CuO first lost lattice oxygen as an oxygen carrier to generate Cu_(2)O,which,in turn,reacted with H_(2)S to generate Cu_(2)*** study provided efficient guidance and reference for OC design in CLG.

关键词： Metal-supported composite phosphogypsum Reaction characteristics Thermodynamic mechanism Chemical looping gasification