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Oxidative Stress in Collegiate Cross Country Skiers in Mid- and Post-Seasons

journal of Biosciences and Medicines 2024年第5期12卷 99-110页

作者： Scott P. jerome kriya L. Dunlap Ava M. Parrish Matthew L. Lowman Emily M. Shipman lawrence k. Duffy Arleigh j. Reynolds Department of Chemistry & Biochemistry University of Alaska Fairbanks Fairbanks AK USA Institute of Arctic Biology University of Alaska Fairbanks Fairbanks AK USA Department of Biology & Wildlife University of Alaska Fairbanks Fairbanks AK USA Department of Veterinary Medicine University of Alaska Fairbanks Fairbanks AK USA

Purpose: The oxidative stress (OS) hypothesis of overtraining syndrome argues that increased production of free radicals through exercise cause muscle fatigue and damage resulting in lower athletic performance. Several studies have investigated OS immediately before and after exercise bouts in a training macrocycle. Our study aimed to compare OS of endurance athletes between a competition macrocycle and the immediate post-season recovery macrocycle. In addition, we aimed to identify athletes who experienced an unexplainable drop in athletic performance during the competition season in order to compare their OS to those who experienced no drop in performance. Methods: Fifteen members of the University of Alaska Fairbanks cross country ski team volunteered for this study. Blood samples were taken in early February (“mid-season”) and late April (“post-season”). Participants completed questionnaires regarding physical activity and athletic performance at the time of the blood draws. Plasma was analyzed for 4-hydroxynonenal (HNE), nitrotyrosine, nitric oxide (NOX), and superoxide dismutase (SOD). Significance was determined by Wilcoxon and Mann-Whitney tests. Results: Participants displayed significantly higher (p Conclusion: Signs of oxidative stress and mitigation during the post-season recovery macrocycle were higher in athletes who reported experiencing a drop in athletic performance during the competition season macrocycle.

关键词： Oxidative Stress 4-Hydroxynonenal Superoxide Dismutase Athletic Performance Training Macrocycle

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Nat Genet:单细胞分析解开结直肠癌细胞的神秘面纱

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现代生物医学进展 2017年第15期17卷 I0003-I0003页

作者： Huipeng Li, Elise T Courtois, Debarka Sengupta, Yuliana Tan Shyam Prabhakar Elise T Courtois, Yuliana Tan Paul Robson Debarka Sengupta kok Hao Chen, jolene jie Lin Goh Paul jongjoon Choi Say Li kong, Axel M Hillmer Iain Beehuat Tan Clarinda Chua Iain Beehuat Tan Lim kiat Hon Wah Siew Tan Mark Wong lawrence j k wee Iain Beehuat Tan Paul Robson Paul Robson Paul Robson Computational and Systems Biology Genome Institute of Singapore Singapore Developmental Cellomics Laboratory Genome Institute of Singapore Singapore Department of Computer Science and Engineering and Center for Computational Biology Indraprastha Institute of Information Technology Delhi India Synthetic Biology Genome Institute of Singapore Singapore Cancer Therapeutics and Stratified Oncology Genome Institute of Singapore Singapore Department of Medical Oncology National Cancer Centre Singapore Singapore Department of Pathology Singapore General Hospital Singapore Department of Colorectal Surgery Singapore General Hospital Singapore Data Analytics Department Institute for Infocomm Research Singapore Program in Cancer and Stem Cell Biology Duke-NUS Medical School Singapore The jackson Laboratory for Genomic Medicine Farmington Connecticut USA Department of Genetics and Genome Sciences Institute for Systems Genomics University of Connecticut Farmington Connecticut USA Department of Biological Sciences National University of Singapore Singapore.

结合单细胞基因组学和计算机技术，一个研究团队（包括来自杰克逊实验室（jAx）单细胞生物学主任Paul Robson博士在内）鉴定出了11种结直肠癌肿瘤的癌细胞组成及邻近的非癌细胞。这对于更好的肿瘤靶向诊断和治疗很重要。”使用单细胞测... 详细信息

结合单细胞基因组学和计算机技术，一个研究团队（包括来自杰克逊实验室（jAx）单细胞生物学主任Paul Robson博士在内）鉴定出了11种结直肠癌肿瘤的癌细胞组成及邻近的非癌细胞。这对于更好的肿瘤靶向诊断和治疗很重要。”使用单细胞测序。”jAX科学家、这篇发表在Nature Genetics上的文章共同第一作者Elise Courtois说道。”我们可以根据肿瘤中的细胞组成将结直肠癌进一步分类。因为每种亚型的肿瘤病人生存率存在差别，我们的方法将为肿瘤医生提供更多的关于肿瘤预后和治疗的信息。”

关键词：单细胞分析结直肠癌癌细胞 Nat 细胞组成肿瘤病计算机技术细胞生物学

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The pollen tube clear zone: Clues to the mechanism of polarized growth

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journal of Integrative Plant Biology 2015年第1期57卷 79-92页

作者： Peter k.Hepler lawrence j.Winship Biology Department University of Massachusetts School of Natural Science Hampshire College

Pollen tubes usually exhibit a prominent region at their apex called the ＂clear zone＂ because it lacks light refracting amyloplasts. A robust, long clear zone often associates with fast growing pollen tubes, and thus serves as an indicator of pollen tube health. Nevertheless we do not understand how it arises or how it is maintained. Here we review the structure of the clear zone, and attempt to explain the factors that contribute to its formation. While amyloplasts and vacuolar elements are excluded from the clear zone, virtually all other organelles are present including secretory vesicles, mitochondria, Golgi dictyosomes, and the endoplas-mic reticulum （ER）. Secretory vesicles aggregate into an inverted cone appressed against the apical plasma membrane. ER elements move nearly to the extreme apex, whereas mitochondria and Golgi dictyosomes move less far forward. The cortical actin fringe assumes a central position in the control of clear zone formation and maintenance, given its role in generating cytoplasmic streaming. Other likely factors include the tip-focused calcium gradient, the apical pH gradient, the influx of water, and a host of signaling factors （small G-proteins）. We think that the clear zone is an emergent property that depends on the interaction of several factors crucial for polarized growth.

关键词： Actin endoplasmic reticulum myosin polarized growth pollen tube

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Calcium at the Cell Wall-Cytoplast Interface

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journal of Integrative Plant Biology 2010年第2期52卷 147-160页

作者： Peter k.Hepler lawrence j.Winship Department of Biology University of MassachusettsAmherstMA 01003USA School of Natural Science Hampshire CollegeAmherstMA 01002USA

Attention is given to the role of Ca^2＋ at the interface between the cell wall and the cytoplast, especially as seen in pollen tubes. While the cytoplasm directs the synthesis and deposition of the wall, it is less well appreciated that the wall exerts considerable self control and influences activities of the cytoplasm. Ca^2＋ participates as a crucial factor in this two way communication. In the cytoplasm, a [Ca^2＋] above 0.1 μM, regulates myriad processes, including secretion of cell wall components. In the cell wall Ca^2＋ , at 10μM to 10 mM, binds negative charges on pectins and imparts structural rigidity to the wall. The plasma membrane occupies a pivotal position between these two compartments, where selective channels regulate influx of Ca^2＋ , and specific carriers pump the ion back into the wall. In addition we draw attention to different factors, which either respond to the wall or are present in the wall, and usually generate elevated[Ca^2＋ ] in the cytoplasm. These factors include：（i） stretch activated channels; （ii） calmodulin; （iii） annexins; （iv） wall associated kinases; （v） oligogalacturonides; and （vi） extracellular adenosine 5＇-triphosphate. Together they provide evidence for a rich and multifaceted system of communication between the cytoplast and cell wall, with Ca^2＋ as a carrier of information.

关键词： Calcium at the Cell Wall-Cytoplast Interface CNGC

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Control of Cell Wall Extensibility during Pollen Tube Growth

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Molecular Plant 2013年第4期6卷 998-1017页

作者： Peter k. Hepler Caleb M. Rounds lawrence j. Winship Biology Department University of Massachusetts Amherst MA 01003 USA School of Natural Science Hampshire College Amherst MA 01002 USA

In this review, we address the question of how the tip-growing pollen tube achieves its rapid rate of elongation while maintaining an intact cell wall. Although turgor is essential for growth to occur, the local expansion rate is controlled by local changes in the viscosity of the apical wall. We focus on several different structures and underly- ing processes that are thought to be major participants including exocytosis, the organization and activity of the actin cytoskeleton, calcium and proton physiology, and cellular energetics. We think that the actin cytoskeleton, in particular the apical cortical actin fringe, directs the flow of vesicles to the apical domain, where they fuse with the plasma mem- brane and contribute their contents to the expanding cell wall. While pH gradients, as generated by a proton-ATPase located on the plasma membrane along the side of the clear zone, may regulate rapid actin turnover and new polymeri- zation in the fringe, the tip-focused calcium gradient biases secretion towards the polar axis. The recent data showing that exocytosis of new wall material precedes and predicts the process of cell elongation provide support for the idea that the intussusception of newly secreted pectin contributes to decreases in apical wall viscosity and to cell expansion. Other prime factors will be the localization and activity of the enzyme pectin methyl-esterase, and the chelation of calcium by pectic acids. Finally, we acknowledge a role for reactive oxygen species in the control of wall viscosity.

关键词： cell expansion cell walls cytoskeleton dynamics polarity pollen development.

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Improved prediction of clay soil expansion using machine learning algorithms and meta-heuristic dichotomous ensemble classifiers

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Geoscience Frontiers 2022年第1期13卷 268-284页

作者： E.U.Eyo S.j.Abbey T.T.lawrence F.k.Tetteh Department of Geography and Environmental Management University of the West of EnglandBristolUnited Kingdom Research Centre for Fluid and Complex Systems Coventry UniversityCoventryUnited Kingdom Department of Civil Engineering University of BirminghamBirminghamUnited Kingdom

Soil swelling-related disaster is considered as one of the most devastating geo-hazards in modern ***,proper determination of a soil’s ability to expand is very vital for achieving a secure and safe ground for ***,this study has provided a novel and intelligent approach that enables an improved estimation of swelling by using kernelised machines(Bayesian linear regression(BLR)&bayes point machine(BPM)support vector machine(SVM)and deep-support vector machine(D-SVM));(multiple linear regressor(REG),logistic regressor(LR)and artificial neural network(ANN)),tree-based algorithms such as decision forest(RDF)&boosted trees(BDT).Also,and for the first time,meta-heuristic classifiers incorporating the techniques of voting(VE)and stacking(SE)were *** independent scenarios of explanatory features’combination that influence soil behaviour in swelling were *** results indicated BLR as possessing the highest amount of deviation from the predictor variable(the actual swell-strain).REG and BLR performed slightly better than ANN while the meta-heuristic learners(VE and SE)produced the best overall performance(greatest R2 value of 0.94 and RMSE of 0.06%exhibited by VE).CEC,plasticity index and moisture content were the features considered to have the highest level of *** binary classifiers(SVM,D-SVM and BPM)gave better accuracy(average accuracy and recall rate of 0.93 and 0.60)compared to ANN,LR and ***-driven diagnostic test indicated that the meta-heuristic models’best performance occurred when ML training was conducted using k-fold validation ***,it is recommended that the concepts developed herein be deployed during the preliminary phases of a geotechnical or geological site characterisation by using the best performing meta-heuristic models via their background coding resource.

关键词： Artificial neural networks Machine learning Clays Algorithm Soil swelling Soil plasticity

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A system for probing Casimir energy corrections to the condensation energy

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Microsystems & Nanoengineering 2020年第1期6卷 1-12页

作者： Diego Perez-Morelo Alexander Stange Richard W.Lally lawrence k.Barrett Matthias Imboden Abhishek Som David k.Campbell Vladimir A.Aksyuk David j.Bishop Department of ECE Boston UniversityBostonMA 02215USA Physical Measurement Laboratory National Institute of Standards and TechnologyGaithersburgMD 20899USA Institute for Research in Electronics and Applied Physics&Maryland NanoCenter University of MarylandCollege ParkMD 20742USA Division of MSE Boston UniversityBostonMA 02215 USA 54k-MEMS Sarl Rue des Lavannes 172072 St BlaiseSwitzerland Department of Physics Boston UniversityBostonMA 02215USA Department of ME Boston UniversityBostonMA 02215USA Department of BME Boston UniversityBostonMA 02215USA

In this article,we present a nanoelectromechanical system(NEMS)designed to detect changes in the Casimir *** Casimir effect is a result of the appearance of quantum fluctuations in an electromagnetic *** experiments have used nano-or microscale parallel plate capacitors to detect the Casimir force by measuring the small attractive force these fluctuations exert between the two *** this new set of experiments,we aim to directly detect the shifts in the Casimir energy in a vacuum due to the presence of the metallic parallel plates,one of which is a superconductor.A change in the Casimir energy of this configuration is predicted to shift the superconducting transition temperature(T_(c))because of the interaction between it and the superconducting condensation *** our experiment,we take a superconducting film,carefully measure its transition temperature,bring a conducting plate close to the film,create a Casimir cavity,and then measure the transition temperature *** expected shifts are smaller than the normal shifts one sees in cycling superconducting films to cryogenic temperatures,so using a NEMS resonator in situ is the only practical way to obtain accurate,reproducible *** a thin Pb film and opposing Au surface,we observe no shift in T_(c)>12µk down to a minimum spacing of~70 nm at zero applied magnetic field.

关键词： cycling energy film

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The spatial evolution of velocity and density profiles in an arrested salt wedge

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Theoretical & Applied Mechanics Letters 2019年第6期9卷 403-408页

作者： Adam j.k.Yang E.W.Tedford G.A.lawrence Department of Civil Engineering University of British Columbia

The spatial variation in the properties of an arrested salt wedge have been investigated,both analytically and in the *** the laboratory particle image velocimetry and laser induced fluorescence were used to obtain flow velocities and the height of the density *** analytical solution for the profile of interface height,in the absence of interfacial instabilities,has been developed from two-layer internal hydraulic *** evolution of the velocity profile is predicted using a momentum diffusion equation following a Lagrangian frame of reference along the interface of the salt *** centre of the shear layer is predicted to lie above the density interface,with this offset decreasing in the downstream *** theoretical predictions are in good agreement with our laboratory measurements.

关键词： Arrested salt wedge Internal hydraulics Shear layer Asymmetry

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Whole-genome sequencing to detect mutations associated with resistance to insecticides and Bt proteins in Spodoptera frugiperda

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Insect Science 2021年第3期28卷 627-638页

作者： Fang Guan jianpeng Zhang Huiwen Shen Xingliang Wang Amanda Padovan Tom k.Walsh wee Tek Tay karl H.j.Gordon William james Cecilia Czepak Michael Hilary Otim Donald kachigamba Yidong Wu College of Plant Protection Nanjing Agricultural UniversityNanjingChina CSIRO Black Mountain Laboratories Clunies Ross StreetCanberraACTAustralia Escola de Agronomia Universidade Federal de GoiasGoianiaBrazil National Crops Resources Research Institute NamulongeKampalaUganda Department of Agricultural Research Services(DARS) LilongweMalawi

The fall armyworm(FAW),Spodoptera frugiperda,is a major pest native to the Americas that has recently invaded the Old *** mutations in the target-site proteins acetylcholinesterase-1(ace-1),voltage-gated sodium channel(VGSC)and ryanodine receptor(RyR)have been identified in *** as major resistance mechanisms to organophosphate,pyrethroid and diamide insecticides *** in the adenosine triphosphate-binding cassette transporter C2 gene(ABCC2)have also been identified to confer resistance to Cry IF *** this study,we applied a whole-genome sequencing(WGS)approach to identify point mutations in the target-site genes in 150 FAW individuals collected from China,Malawi,Uganda and *** approach revealed three amino acid substitutions(A201S,G227A and F290V)of *** ace-1,which are known to be associated with organophosphate *** Brazilian population had all three ace-1 point mutations and the 227A allele(mean frequency=0.54)was the most *** from China,Malawi and Uganda harbored two of the three ace-1 point mutations(A201S and F290V)with the 290V allele(0.47-0.58)as the dominant *** mutations in VGSC(T929I,L932F and L1014F)and RyR(I4790M and G4946E)were not detected in any of the 150 individuals.A novel 12-bp insertion mutation in exon 15 of the ABCC2 gene was identified in some of the Brazilian individuals but absent in the invasive *** results not only demonstrate robustness of the WGS-based genomic approach for detection of resistance mutations,but also provide insights for improvement of resistance management tactics in ***.

关键词： Bt resistance insecticide resistance mutation detection Spodoptera frugiperda whole-genome sequencing

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Influence of supraphysiological cortisol manipulation on predator avoidance behaviors and physiological responses to a predation threat in a wild marine teleost fish

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Integrative Zoology 2018年第2期13卷 206-218页

作者： Michael j.lawrence Erika j.ELIASON jacob W.BROWNSCOMBE kathleen M.GILMOUR john W.MANDELMAN Lee F.G.GUTOWSkY Steven j.COOkE Fish Ecology and Conservation Physiology Laboratory Department of BiologyCarleton UniversityOttawaOntarioCanada Department of Ecology Evolution&Marine BiologyUniversity of CaliforniaSanta BarbaraCaliforniaUSA Department of Biology University of OttawaOttawaOntarioCanada School for the Environment University of New EnglandBiddefordMaineUSA john H.Prescott Marine Laboratory New England AquariumBostonMassachusettsUSA

The stress axis in teleost fish attempts to maintain internal homeostasis in the face of allostatic ***,stress axis induction has been associated with a higher predation rate in *** date,the physiological and behavioral factors associated with this outcome are poorly *** purpose of the present study was to investigate the impact of experimental cortisol elevation on anti-predator behavior and physiological responses to predator *** hypothesized that semi-chronic cortisol elevation would increase susceptibility to predation by increasing stress-induced risk-taking *** test this hypothesis,schoolmaster snapper were given cocoa butter implants without cortisol(sham)or with cortisol(50 mg/kg body weight)and tethered to *** were exposed to either a lemon shark or control conditions for *** use and activity were recorded throughout and fish were terminally sampled for *** implantation,relative to shams,resulted in higher blood glucose and plasma cortisol concentrations with a lower plasma lactate *** exposure,relative to controls,elicited higher blood glucose and lactate concentrations but had no effect on plasma cortisol *** interactions were detected between shark exposure and cortisol treatment for any physiological *** metrics,including shelter use and activity,were unaffected by either cortisol implantation or shark *** responses to cortisol implantation likely resulted from enhanced gluconeogenic activity,whereas alterations under predator exposure may have been the product of catecholamine *** work should address context-specific influences of stress in mediating behavioral responses to predation.

关键词： homeostatic overload lemon shark predation refuging stress axis teleost physiology

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