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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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The EPSPS Pro106Ser substitution solely accounts for glyphosate resistance in a goosegrass(Eleusine indica) population from Tennessee, United States

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journal of Integrative Agriculture 2016年第6期15卷 1304-1312页

作者： janel L Huffman Chance w Riggins lawrence E Steckel Patrick j Tranel Department of Crop Sciences University of Illinois Urbana IL 61801 USA Department of Plant Sciences University of Tennessee Jackson TN 38301 USA

Previous studies have documented the occurrence of glyphosate-resistant （GR） goosegrass （Eleusine indica （L.） Gaertn.） and, in at least some cases, resistance is due to an altered target site. Research was performed to determine if an altered target site was responsible for GR in a Tennessee, United States goosegrass population （TennGR）. DNA sequencing revealed a mutation in TennGR plants conferring the Prol06Ser 5-enolpyruvylshikimate-3-phosphate synthase （EPSPS） substitution previously identified in other GR populations. F2 populations were derived from TennGR plants crossed with plants from a glyphosate-susceptible population （TennGS） and analyzed for their response to glyphosate and genotyped at the EPSPS locus. Plants from the F2 populations segregated 1：2：1 sensitive：intermediate：resistant in response to a selec- tive dose of glyphosate, and these responses co-segregated with the EPSPS genotypes （PP106, PS106, and SS106）. To separately investigate the effect of the Prol06Ser substitution on GR, glyphosate dose-response curves and 50% effective dose （EDso） values were compared among the three genotypes and the two parental populations. The SS106 genotype was 3.4-fold resistant relative to the PP106 genotype, identical to the resistance level obtained when comparing the resistant and susceptible parental populations. we conclude that the mutation conferring a Prol06Ser EPSPS mutation is solely responsible for GR in the TennGR goosegrass population.

关键词： herbicide resistance monogenic trait glyphosate PCR amplification of specific alleles (PASA) EPSPS target-site mutation

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The best of the future of business lawrence j. Gitman, Carl McDaniel 1st Edition

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2003年

作者： lawrence j. Gitman Carl McDaniel

来源：畅想之星图书光盘版（南... 评论

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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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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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NEw MURID RODENTS FROM THE LATE CENOZOIC OF YUSHE BASIN, SHANXI

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古脊椎动物学报(中英文） 1992年第1期 29-38+87-88页

作者： lawrence j.Flynn Harvard University NY Research Associate American Museum of Natural History and Peabody Museum

As scientific collaborators of the Chinese-American joint project "Neogene Rocks and Faunas, Yushe Basin, Shanxi, PRC", the present authors, with william R. Downs, Northern Arizona University, sampled the Yushe microfauna in the fall of 1987 and 1988. The fossil temains were retrieved by surface collection and by wet-sieving bulk quantities of sediment.

关键词： Yushe Basin Late cenozoic murids new taxa

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Co-author weighting in Bibliometric Methodology and Subfields of a Scientific Discipline

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journal of Data and Information Science 2020年第3期5卷 84-96页

作者： lawrence Smolinsky Aaron j Lercher Department of Mathematics Louisiana State UniversityBaton RougeLA 70803USA Middleton Library Louisiana State UniversityBaton RougeLA 70803USA

Purpose: To give a theoretical framework to measure the relative impact of bibliometric methodology on the subfields of a scientific discipline, and how that impact depends on the method of evaluation used to credit individual scientists with citations and publications. The authors include a study of the discipline of physics to illustrate the method. Indicators are introduced to measure the proportion of a credit space awarded to a subfield or a set of ***/methodology/approach: The theoretical methodology introduces the notion of credit spaces for a discipline. These quantify the total citation or publication credit accumulated by the scientists in the discipline. One can then examine how the credit is divided among the subfields. The design of the physics study uses the American Physical Society print journals to assign subdiscipline classifications to articles and gather citation, publication, and author information. Credit spaces for the collection of Physical Review journal articles are computed as a proxy for ***: There is a substantial difference in the value or impact of a specific subfield depending on the credit system employed to credit individual *** limitations: Subfield classification information is difficult to obtain. In the illustrative physics study, subfields are treated in groups designated by the Physical Review journals. while this collection of articles represents a broad part of the physics literature, it is not all the literature nor a random *** implications: The method of crediting individual scientists has consequences beyond the individual and affects the perceived impact of whole subfields and institutions. Originality/value: The article reveals the consequences of bibliometric methodology on subfields of a disciple by introducing a systematic theoretical framework for measuring the consequences.

关键词： Citation analysis Bibliometrics Research evaluation Co-author

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Involvement of eicosanoids in the pathogenesis of pancreatic cancer: the roles of cyclooxygenase-2 and 5-lipoxygenase

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world journal of Gastroenterology 2014年第31期20卷 10729-10739页

作者： lawrence M Knab Paul j Grippo David j Bentrem Department of Surgery Northwestern University Feinberg School of Medicine Robert H Lurie Comprehensive Cancer Center Northwestern University jesse Brown VA Medical Center

The interplay between inflammation and cancer progression is a growing area of research. A combination of clinical, epidemiological, and basic science investigations indicate that there is a relationship between inflammatory changes in the pancreas and neoplastic progression. Diets high in ω-6 polyunsaturated fatty acids provide increased substrate for arachidonic acid metabolism by cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) to form eicosanoids. These eicosanoids directly contribute to pancreatic cancer cell proliferation. Both COX-2 and 5-LOX are upregulated in multiple cancer types, including pancreatic cancer. In vitro studies using pancreatic cancer cell lines have demonstrated upregulation of COX-2 and 5-LOX at both the mRNA and protein levels. when COX-2 and 5-LOX are blocked via a variety of mechanisms, cancer cell proliferation is abrogated both in vitro and in vivo. The mechanism of COX-2 has been shown to include effects on apoptosis as well as angiogenesis. 5-LOX has been implicated in apoptosis. The use of COX-2 and 5-LOX inhibitors in clinical studies in patients with pancreatic cancer has been limited. Patient enrollment has been restricted to those with advanced disease which makes evaluation of these drugs as chemopreventive agents difficult. COX-2 and 5-LOX expression have been shown to be present during the early neoplastic changes of pancreatic cancer, well before progression to invasive disease. This indicates that the ideal role for these interventions is early in the disease process as preventive agents, perhaps in patients with chronic pancreatitis or hereditary pancreatitis.

关键词： Arachidonic acid Eicosanoid Cyclooxygenase-2 5-lipoxygenase Pancreatic cancer Inflammation

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The sky is not falling!

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Economic and Political Studies 2019年第2期7卷 122-147页

作者： lawrence j.Lau Lau Chor Tak Institute of Global Economics and Finance The Chinese University of Hong KongHong Kong SARChina

As of October 2018,almost half of US imports of goods from China are subject to new US tariffs at various rates,mostly at 10%until the year-end of 2018,when the rates were scheduled to be raised to 25%.These tariff rates will prove to be prohibitive for most if not all of the US imports from *** that US imports from China will be reduced by half,the initial direct real impact on the Chinese economy may be estimated at a loss of 0.43%of *** indirect effects are included,the full real impact may be estimated at a maximum loss of 1.12%of Chinese *** estimated impacts are relatively small and quite *** is a possibility that the scope of the US tariffs may be expanded to cover all US imports from China,in which case the full negative economic impact will be doubled,but still leaving an expected rate of economic growth in excess of 4%.The Renminbi is not likely to be significantly devalued as a result of the trade ***,there are also longer-term underlying forces at work behind the China–US trade war–the competition for economic and technological dominance and the rise of populism,isolationism,nationalism and *** is important for China–US relations,and China’s relations with the rest of the world,in particular with the European Union,Association of Southeast Asian Nations(ASEAN),japan and Russia,to be carefully managed going forward.

关键词： International trade trade war trade surplus tariff China–US relationship

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