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A fractional differential constitutive model for dynamic stress intensity factors of an anti-plane crack in viscoelastic materials

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Acta Mechanica Sinica 2014年第3期30卷 403-409页

作者： Run-Tao Zhan zhao-xia li Lei Wang Department of Engineering Mechanics Southeast UniversityJiangsu Key Laboratory of Engineering Mechanics School of Civil Engineering Southeast University

Fractional differential constitutive relationships are introduced to depict the history of dynamic stress inten- sity factors （DSIFs） for a semi-infinite crack in infinite viscoelastic material subjected to anti-plane shear impact load. The basic equations which govern the anti-plane deformation behavior are converted to a fractional wave-like equation. By utilizing Laplace and Fourier integral transforms, the fractional wave-like equation is cast into an ordinary differential equation （ODE）. The unknown function in the solution of ODE is obtained by applying Fourier transform directly to the boundary conditions of fractional wave-like equation in Laplace domain instead of solving dual integral equations. Analytical solutions of DSIFs in Laplace domain are derived by Wiener-Hopf technique and the numerical solutions of DSIFs in time domain are obtained by Talbot algorithm. The effects of four parameters α, β, b1, b2 of the fractional dif- ferential constitutive model on DSIFs are discussed. The numerical results show that the present fractional differential constitutive model can well describe the behavior of DSIFs of anti-plane fracture in viscoelastic materials, and the model is also compatible with solutions of DSIFs of anti-plane fracture in elastic materials.

关键词： Dynamic fracture Stress intensity factors Fractional differentiation - Anti-plane fracture Viscoelasticmaterial Wiener-Hopf

Gene Sequence, Soluble Expression and Homologous Comparison of a D-Hydantoinase fromPseudomonas putida YZ-26

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Chemical Research in Chinese Universities 2005年第5期21卷 552-557页

作者： SHI Ya-wei zhao li-xia NIU li-xi FENG xia YUAN Jing-ming Key Laboratory for Chemical Biology and Molecular Engineering of Ministry of Education Institute of Biotechnology Shanxi University Taiyuan 030006 P. R. China

A 1440bp open-reading frame encoding D-hydantoinase from Pseudomonas putida YZ-26 was cloned and sequenced（ GenBank AY387829）. The DNA fragment was inserted into Nde and BamHI sites of vector pET-3a, yielding a recombinant plasmid, pET-HDT. After being transferred into the host strain, the artificial strain, pET-HDT/ E. coli BL21 can express the D-hydantoinase as the soluble form in the Lura-Bertani medium without addition of any inducers. The activity of the enzyme toward substrate DL-hydantoin can reach 3000-4000 IU per cells from one-liter bacterial culture incubated at 30 ℃ for 10-12 h. By the comparison of amino acid sequence homology, hydrophobic residues analysis and secondary structure prediction, it was found that D-hydantoinase reported herein is quite similar to that from Pseudomonas putdia CCRC12857, and alike to that from Pseudomonas putdia DSM84 or other bacteria. A rapid and efficient purification procedure of the enzyme was performed by a three-step procedure： ammonium sulfate fractionation, phenyl Sepharose hydrophobic interaction chromatography and Sephacryl S-200 gel filtration. The molecular mass of the monomeric enzyme is 52042 Da as determined by MALDI-TOF mass spectrometry.

关键词： D-Hydantoinase Gene sequence Soluble expression Homologous comparison Purification Mass spectrum

Study on superoxide and hydroxyl radicals generated in indirect electrochemical oxidation by chemiluminescence and UV-Visible spectra

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Journal of Environmental Sciences 2008年第8期20卷 1006-1011页

作者： ZHANG, Bo-Tao zhao, li-xia liN, Jin-Ming State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Department of Chemistry Tsinghua University Beijing 100084 China

The generation and transformation of radicals on the cathode of indirect electrochemical oxidation were studied by chemilumines- cence(CL)and UV-Visible spectra in the reactor with a salt bridge that connected the separated *** CL intensity of 4×10^(-9)mol/L luminol on the cathode with bubbling oxygen was about seven times that of the intensity without it,which was because of the generation of reactive oxygen species(ROS).The existence of ROS,especially the generation of the superoxide radical,coul...

关键词： chemiluminescence(CL) UV-Visible radical indirect electrochemical oxidation

丙泊酚通过Fox O1/TXNIP信号通路介导自噬对高糖诱导心肌细胞损伤的作用

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中国临床药理学杂志 2024年第16期40卷 2344-2348页

作者：杨育明彭粤韩红任从才赵丽霞中山大学附属第八医院(深圳福田)麻醉科广东深圳518000

目的探讨丙泊酚(Pro)通过叉头盒蛋白O1(Fox O1)/硫氧还蛋白相互作用蛋白(TXNIP)信号通路介导自噬对高糖(HG)诱导心肌细胞损伤的影响。方法将H9c2细胞分为空白组(5.5 mmol·L^(-1)葡萄糖)、高葡萄糖(HG)组(30 mmol·L^(-1)葡萄糖)、HG+Pr... 详细信息

目的探讨丙泊酚(Pro)通过叉头盒蛋白O1(Fox O1)/硫氧还蛋白相互作用蛋白(TXNIP)信号通路介导自噬对高糖(HG)诱导心肌细胞损伤的影响。方法将H9c2细胞分为空白组(5.5 mmol·L^(-1)葡萄糖)、高葡萄糖(HG)组(30 mmol·L^(-1)葡萄糖)、HG+Pro组(30 mmol·L^(-1)葡萄糖+25μmol·L^(-1)Pro)、HG+Pro+阴性对照(OE NC)组(先转染OE NC,再以30 mmol·L^(-1)葡萄糖+25μmol·L^(-1)Pro处理)、HG+Pro+Fox O1过表达质粒(Fox O1-OE)组(先转染Fox O1-OE,再以30 mmol·L^(-1)葡萄糖+25μmol·L^(-1)Pro处理)。用细胞计数试剂盒-8(CCK-8)法、原位末端转移酶标记技术(TUNEL)法、酶联免疫吸附试验(EliSA)、透射电镜、蛋白质印迹法(Western blot)分别检测细胞存活率、凋亡率、上清液中超氧化物歧化酶(SOD)、丙二醛(MDA)水平以及自噬体、Fox O1/TXNIP及自噬蛋白表达水平变化。结果空白组、HG组、HG+Pro组、HG+Pro+OE NC组、HG+Pro+Fox O1-OE组细胞活力分别为(100.00±0.00)%、(48.15±4.82)%、(79.66±7.98)%、(78.89±7.91)%和(49.22±4.93)%,凋亡率分别为(12.04±1.21)%、(42.34±4.25)%、(26.22±2.63)%、(27.02±2.71)%和(38.29±3.86)%,SOD水平分别为(62.24±6.25)、(28.21±2.85)、(55.37±5.58)、(55.09±5.53)和(30.66±3.08)U·mg^(-1)pro,MDA水平分别为(0.38±0.04)、(1.43±0.15)、(0.67±0.07)、(0.72±0.08)和(1.34±0.14)U·mg^(-1)pro,自噬体数量分别为(6.24±0.63)、(13.05±1.32)、(8.31±0.84)、(8.55±0.86)和(12.22±1.23)个,磷酸化Fox O1(p-Fox O1)/Fox O1比值分别为0.34±0.04、0.86±0.09、0.48±0.05、0.43±0.05和0.74±0.08,TXNIP表达分别为0.24±0.03、0.62±0.08、0.38±0.04、0.36±0.04和0.58±0.06,Bcelin-1表达分别为1.12±0.12、0.53±0.06、1.02±0.11、1.05±0.11和0.62±0.07,p62表达分别为0.56±0.06、1.56±0.16、0.82±0.09、0.86±0.09和1.44±0.15。HG组的上述指标与空白组比较,HG+Pro组的上述指标与HG组比较,HG+Pro+Fox O1-OE组的上述指标与HG+Pro+OE NC组比较,在统计学上差异均有统计学差异(均P<0.05)。结论Pro通过抑制Fox O1/TXNIP信号通路抑制自噬,改善HG诱导心肌细胞损伤。

关键词：丙泊酚叉头盒蛋白O1/硫氧还蛋白相互作用蛋白信号通路自噬高糖心肌细胞损伤

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硫酸镁在子痫前期治疗中的争议及其不良反应

国际妇产科学杂志 2024年第4期51卷 448-452页

作者：赵丽霞王小青长治医学院山西省长治市046000 大同市第三人民医院产科

子痫前期是妊娠期导致母儿不良妊娠结局的特发性疾病。解痉是治疗子痫前期的重要且有效手段,硫酸镁是一线解痉药物。目前硫酸镁在治疗子痫前期中仍存在着一些争议,包括:非重度子痫前期是否用硫酸镁治疗,既往研究不推荐应用硫酸镁预防子... 详细信息

子痫前期是妊娠期导致母儿不良妊娠结局的特发性疾病。解痉是治疗子痫前期的重要且有效手段,硫酸镁是一线解痉药物。目前硫酸镁在治疗子痫前期中仍存在着一些争议,包括:非重度子痫前期是否用硫酸镁治疗,既往研究不推荐应用硫酸镁预防子痫发作,但近年研究认为,子痫前期患者应酌情使用硫酸镁预防子痫;关于产前硫酸镁治疗子痫前期的使用疗程问题,近年研究认为硫酸镁的使用疗程应该小于24 h;产后硫酸镁预防子痫发作,现有的研究支持产后硫酸镁应用可以小于24 h,甚至不使用;硫酸镁使用后相关的不良反应,包括增加母体产后出血风险,引起母体高镁血症、低钙血症,导致新生儿低钙血症、影响骨钙沉积和新生儿高钾血症等。

关键词：硫酸镁先兆子痫子痫药物相关性副作用和不良反应高镁血症治疗

Evolution of inner wall wrinkle defects in the sinking zone of a thick-walled steel tube during radial forging

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Advances in Manufacturing 2024年第2期12卷 396-408页

作者： Yu-zhao Yang Cheng Xu li-xia Fan School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094People’s Republic of China

An axial wrinkle defect was observed in the inner wall of the sinking zone of a thick-wall steel tube processed by cold radial *** can evolve into *** present study focuses on the evolution of wrinkles and the effects of process parameters on them using a three-dimensional radial forging process finite element model,radial forging experiments,and surface morphology *** results indicated that the vertical section angle of the hammer die and the size of the tube blank significantly affect the evolution of *** height-to-width ratioλwas introduced to describe the morphology of *** had an approximately linear relationship with the radius reduction in the sinking *** was a linear correlation between the growth slope ofλand the axial to circumferential strain ratio|εr/εθ|,which can predict theλunder few process *** the 30SiMn2MoVA steel,at the junction of the forging and sinking zones,the threshold ofλof the wrinkle that can evolve into a fissure is approximately 1.123.

关键词： Radial forging Inner wall Wrinkle defects Evolution Sinking zone

比浊法测定土壤有效硫的优化及与ICP-OES法对比

维普期刊数据库评论

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中国土壤与肥料 2024年第1期 238-246页

作者：潘政赵丽霞陕红占国艳潘晓威梁耀辉刘丽丽欧阳小雪孙宝利叶剑芝中国热带农业科学院农产品加工研究所/农业农村部农产品加工质量安全风险评估实验室(湛江) 广东湛江524001 农业农村部环境保护科研监测所/农田有机污染生物消减创新团队/农业农村部产地环境污染防控重点实验室/天津市农业环境与农产品安全重点实验室天津300191 中国农业科学院农业环境与可持续发展研究所/农业农村部农业环境重点实验室北京100081 天津市农业科学院农产品质量安全与营养研究所天津300381

第三次全国土壤普查意义重大,为确保普查数据真实可靠,需对行业标准检测方法进行反复验证以优选出适合在全国范围内推广的方法。由于NY/T 1121.14—2006比浊法测定土壤有效硫标准曲线线性较差,亟须优化其提取、测定条件以提高方法的准... 详细信息

第三次全国土壤普查意义重大,为确保普查数据真实可靠,需对行业标准检测方法进行反复验证以优选出适合在全国范围内推广的方法。由于NY/T 1121.14—2006比浊法测定土壤有效硫标准曲线线性较差,亟须优化其提取、测定条件以提高方法的准确度和精密度。鉴于此,主要探究了沉淀剂的状态、品牌及线性拟合方式对比浊法测定土壤有效硫标准曲线线性的影响,结果表明,有效硫标准曲线改用现用现配的40 g/L氯化钡溶液定容可显著提高标准曲线的线性,使其相关系数r>0.999,满足分析测试的要求。同时本实验室对电感耦合等离子体光谱法(ICP-OES)测定土壤有效硫进行方法验证、对比,比浊法、ICP-OES法的检出限分别为1.20、0.80 mg/kg,均满足分析测试的要求。方法准确度和精密度验证结果表明,二者均可用于土壤有效硫的测定并且测定结果无显著性差异。其中,比浊法适用于测定低含量(<48 mg/kg)样品,ICP-OES法适用于含量范围在0~150 mg/kg的样品。结合本实验室在第三次全国土壤普查内业检测试点工作中的经验,建议将ICP-OES法作为第三次全国土壤普查有效硫测定的首选方法,以期为第三次全国土壤普查内业检测提供参考和借鉴。

关键词：第三次全国土壤普查有效硫比浊法电感耦合等离子体光谱仪

利用DXA评估系统性红斑狼疮患者中肌少症的现患率

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广东医学 2024年第5期45卷 603-609页

作者：李朝霞欧阳辉黎晓萱徐浩周毅暨南大学附属第一医院风湿免疫科广东广州510630 暨南大学附属第一医院康复科广东广州510630 暨南大学附属第一医院核医学科广东广州510630

目的评估系统性红斑狼疮(systemic lupus erythematosus,SLE)患者中肌少症的现患率,分析SLE共病肌少症患者的体成分变化,探讨SLE患者肌少症发生的危险因素。方法共纳入114例SLE患者(病例组)和114例健康对照者(对照组)。采用双能X线吸收... 详细信息

目的评估系统性红斑狼疮(systemic lupus erythematosus,SLE)患者中肌少症的现患率,分析SLE共病肌少症患者的体成分变化,探讨SLE患者肌少症发生的危险因素。方法共纳入114例SLE患者(病例组)和114例健康对照者(对照组)。采用双能X线吸收法(dual energy X-ray absorptiometry,DXA)测量两组的肌肉质量,通过握力和步速分别评估患者的肌力和体能。根据欧洲老年人肌少症工作组及亚洲肌少症工作组诊断标准对SLE患者进行肌少症诊断及分期,将SLE患者分为肌少症组及非肌少症组,比较组间患者的体成分及骨密度等指标的差异,分析SLE患者共病肌少症的影响因素。结果SLE患者的平均病程为(79.6±72.8)个月。45.6%(n=52)的SLE患者共病肌少症,其中22.8%(n=26)的患者为肌少症前期,16.7%(n=19)的患者为肌少症期,6.1%(n=7)的患者为严重肌少症期。肌少症组患者的体重、体质指数、脂肪质量指数、全身瘦组织含量、瘦质量指数、全身去脂体重、去脂体重指数均低于非肌少症组和对照组。肌少症组的骨矿物质含量、腰椎和股骨骨密度明显低于对照组。多因素回归分析显示,体质指数(OR=0.61,P<0.001,95%CI:0.49~0.75)和职业劳动强度(OR=2.0,P=0.009,95%CI:1.19~3.34)是SLE患者共病肌少症的影响因素。结论SLE患者中约半数共病肌少症,共病肌少症SLE患者的脂肪、肌肉含量和重要部位骨密度下降,其中体质指数和职业劳动强度是SLE患者出现肌少症的影响因素。

关键词：系统性红斑狼疮体成分双能X线吸收法肌少症骨密度

Potential of arbuscular mycorrhizal fungi for soil health:A review

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Pedosphere 2024年第2期34卷 279-288页

作者： Junling ZHANG Ruotong zhao xia li Jiangzhou ZHANG College of Resources and Environmental Sciences National Academy of Agriculture Green DevelopmentKey Laboratory of Plant-Soil InteractionsMinistry of EducationChina Agricultural UniversityBeijing 100193China College of Agronomy and life Science Shanxi Datong UniversityDatong 037009China College of Resources and Environment/International Magnesium Institute Fujian Agriculture and Forestry UniversityFuzhou 350002China

Soil health is an important component of“One Health”.Soils provide habitat to diverse and abundant *** microbial diversity and functions is essential for building healthy soils towards sustainable *** mycorrhizal fungi(AMF)form potentially symbiotic associations with approximately 80%of land plant species that are well recognized for carbon flux and nutrient *** addition to disentangling the signaling pathways and regulatory mechanisms between the two partners,recent advances in hyphosphere research highlight some emerging roles of AMF and associated microbes in the delivery of soil *** paper reviews the contribution of AMF to soil health in agroecosystems,with a major focus on recent progress in the contribution of hyphosphere microbiome to nutrient cycling,carbon sequestration,and soil *** hyphosphere microbiome and fungal stimulants open avenues for developing new fertilizer formulas to promote AMF *** practice,developing AMF-friendly management strategies will have long-term positive effects on sustainable agriculture aiming at simultaneously providing food security,increasing resource use efficiency,and maintaining environment integrity.

关键词： arbuscular mycorrhizal fungi-friendly management strategies carbon sequestration hyphosphere microbiome nutrient cycling soil aggregation soilfunctions