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Fading indirect effects in a warming arctic tundra

Current Zoology 2014年第2期60卷 189-202页

作者： Joēl BETY Maude GRAHAM-SAUVE Pierre LEGAGNEUX Marie-Christine CADIEUX Gilles gauthier Centre d'études nordiques et D6partement de biologie Universit6 du Québec à Rimouski 300 All6e des Ursulines Rimouski Qu6bec Canada G5L 3Al Centre d'études nordiques et Département de biologie Pavilion Vachon Université Laval Qu6bec Qu6bec Canada G 1K 7P4

Indirect interactions in food webs can strongly influence the net effect of global change on ecological communities yet they are rarely quantified and hence remain poorly understood. Using a 22-year time series, we investigated climate-induced and predator-mediated indirect effects on grazing intensity in the tundra food web of Bylot Island, which experienced a warming trend over the last two decades. We evaluated the relative effects of environmental parameters on the proportion of plant biomass grazed by geese in wetlands and examined the temporal changes in the strength of these cascading effects. Migrating geese are the dominant herbivores on Bylot Island and can consume up to 60% of the annual production of wetland graminoids. Spring North Atlantic Oscillation, mid-summer temperatures and summer abundance of lemmings (prey sharing predators with geese) best-explained annual variation in grazing intensity. Goose grazing impact increased in years with high temperatures and high lemming abundance. However, the strength of these indirect effects on plants changed over time. Grazing intensity was weak.y explained by environmental factors in recent years, which were mark.d by a sharp increase in plant primary production and steady decrease in grazing pressure. Indirect effects do not seem to be reversing the direct positive effect of warming on wetland plants. We suggest that cascading effects on plants may lag considerably behind direct effects in vertebrate dominated arctic communities, especially where k.y herbivore populations are strongly affected by factors outside of the Arctic.

关键词：变暖趋势间接北极植物生物量放牧强度淡入北大西洋涛动湿地植物

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Volatilization of heavy metals during incineration of municipal solid wastes

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Journal of Environmental Sciences 2004年第4期16卷 635-639页

作者： SUNLu-shi S.Abanades J.D.Lu G.Flamant D.gauthier Statek.ylaboratoryofCoalCombustion HuazhongUniversityofScienceandTechnologyWuhan430074China InstitutdeScienceetdeG6niedesMat6riauxetProc6d6s（CNRS-IMP） BP50deillo66125Font-RomeuCedexFrance

Incineration experiments with MSW, which had been impregnated with heavy metals, were presented to obtain information on the volatilization behavior of the elements cadmium(Cd), lead(Pb), and zinc(Zn) under different conditions. Experiments were carried out in a bubbling fluid bed system connected to a customized inductively coupled plasma optical emission spectroscopy(ICP-OES) for analyzing metals in the flue gas. The results indicated that the combustion temperature, the gas atmosphere, and the chlorine content in the flue gas could affect the volatilization behavior of heavy metals. In the fluidized bed combustion, a large surface area was provided by the bed sand particles, and they may act as absorbents for the gaseous ash-forming compound. Comparer with the metals Cd and Pb, the vaporization of Zn was low. The formation of stable compounds such as ZnO·Al 2O 3 could greatly decrease the metals volatilization. The presence of chlorine would enhance the volatilization of heavy metals by increasing the formation of metal chlorides. However, when the oxygen content was high, the chlorinating reaction was k.netically hindered, which heavy metals release would be delayed.

关键词： municipal solid waste incineration heavy metal emission fluidized bed

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Nitric Oxide in Plants： Production and Cross-talk.with Ca^2＋ Signaling

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Molecular Plant 2008年第2期1卷 218-228页

作者： Angelique Besson-Bard Cecile Courtois Adrien gauthier Jennifer Dahan Grazyna Dobrowolsk. Sylvain Jeandroz Alain Pugin David Wendehenne Unite Mixte de Recherche INRA 1088/CNRS 5184/Universite de Bourgogne Plante-Microbe-Environnement 17 rue Sully BP 86510 21065 Dijon cedex France Institute of Biochemistry and Biophysics Polish Academy of Sciences 02-106 Warsaw Poland Unite Mixte de Recherche UHP INRA 1136 Interactions Arbres/Micro-Organismes Universite Henry Poincare Nancy I BP 239 54506 Vandoeuvre cedex France

Nitric oxide （NO） is a diatomic gas that performs crucial functions in a wide array of physiological processes in animals. The past several years have revealed much about its roles in plants. It is well established that NO is synthesized from nitrite by nitrate reductase （NR） and via chemical pathways. There is increasing evidence for the occurrence of an alternative pathway in which NO production is catalysed from L-arginine by a so far non-identified enzyme. Contradictory results have been reported regarding the respective involvement of these enzymes in specific physiological conditions. Although much remains to be proved, we assume that these inconsistencies can be accounted for by the limited specificity of the pharmacological agents used to suppress NO synthesis but also by the reduced content of L-arginine as well as the inactivity of nitrate-permeable anion channels in nitrate reductase- and/or nitrate/nitrite-deficient plants. Another unre- solved issue concerns the molecular mechanisms underlying NO effects in plants. Here, we provide evidence that the second messenger Ca^2＋, as well as protein k.nases including MAPk.and SnRk., are very plausible mediators of the NO signals. These findings open new perspectives about NO-based signaling in plants.

关键词： Nitric Oxide in Plants Production and Cross-talk Ca~(2+) Signaling

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Influence of mixed organosilane coatings with variable RGD surface densities on the adhesion and proliferation of human osteosarcoma Saos-2 cells to magnesium alloy AZ31

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Bioactive Materials 2017年第1期2卷 35-43页

作者： Xiaoxi Yang Afrah Al Hegy Eric R.gauthier Joy Gray-Munro Dept.of Chemistry and Biochemistry Laurentian UniversitySudburyOntarioP3E 2C6Canada

In the last decade,the use of magnesium and its alloys as biodegradable implant materials has become increasingly ***,surface modification of these materials to control the degradation rate in the early stages of healing and improve their biocompatibility is crucial to the successful implementation of magnesium alloy implants in *** adhesion and proliferation at the implant surface is a vital factor for successful integration of a biomaterial within the *** accomplish this task.by binding to ligands such as the arginine-glycine-aspartic acid peptide sequence(RGD)commonly found on adhesive proteins present in the extracellular *** this paper,we report a biomimetic surface modification strategy involving deposition of a mixed organosilane layer on Mg AZ31 followed by covalent immobilization of RGD peptides through a heterobifunctional cross-link.r *** results indicate that with optimized deposition conditions uniform organosilane coatings were successfully deposited on the Mg AZ31 ***,we have demonstrated that the surface density of immobilized RGD can be varied by depositing organosilane layers from solutions containing two different organosilanes in specified *** in cell adhesion and cell proliferation were observed on the surface modified substrates.

关键词： Magnesium alloys Biodegradable Biomimetic RGD peptide Surface modification Cell adhesion Organosilane

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Effects of Irrigation and Drought on Growth and Essential Oil Production in O. vulgare and R. officinalis

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American Journal of Plant Sciences 2022年第5期13卷 659-667页

作者： David C. Baudoin Edward Bush Ted gauthier Amy B. Hernandez Heather k.rk.Ballard LSU AgCenter School of Plant Environmental & Soil Sciences Miller Hall USA

The essential oil industry has led a rapidly growing mark.t in American herbal medicine. The global essential oil industry was valued at an estimated 18.6 billion USD in 2020 and is expected to have a compound annual growth rate of 7.6% from 2020 to 2027. “Essential oil” is a broad term used to describe volatile organic compounds (VOCs) that are often associated with a plant’s essence or aroma. These molecules are commonly extracted from a variety of different plant structures by steam distillation and cold pressing. Essential oils function as a defense against insects, bacteria, fungi, and other stressors, such as drought and cold. The most industrially important of this class of compounds are monoterpenes, steam-volatile constituents which are the most abundant terpenes throughout plants. Essential oils may include monoterpenes (two isoprene units), sesquiterpenes (three isoprene units), k.tones, and phenolics. Phenolics include flavonoids, anthocyanins, and tannins.

关键词： Water Relations Essential Oil Extraction Terpenes Plant Environmental Stress Mass Spectroscopy

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The Bianisotropic Formulation of the Plane Wave Method from Faraday’s and Ampere’s Laws

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Optics and Photonics Journal 2021年第8期11卷 360-386页

作者： Robert gauthier Department of Electronics Carleton University Ottawa Canada

The plane wave numerical technique is recast from Ampere’s and Faraday’s laws for materials that are characterized with a bianisotropic form of the constitutive relations. The populating expressions are provided for the eigenvalue matrix system that can be directly solved for the angular frequencies and field profiles when bianisotropy is included. To demonstrate the computation process and expected state diagrams and field profiles, numerical computation examples are provided for a bianisotropic Bragg Array with central defect. It is shown that the location of the magnetoelectric tensor elements has a significant effect on the eigenstates of an equivalent isotropic (anisotropic) structure. One form of the magnetoelectric tensor (diagonal elements only) leads to the observation of merging states and the formation of exceptional points. The numerical approach presented can be implemented as an add-on to the familiar plane wave numerical technique.

关键词： Bianisotropic Magnetoelectric Plane Wave Method Exceptional Point

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Associations of AT(N) biomark.rs with neuropsychiatric symptoms in prechnical Alzheimer’s disease and cognitively unimpaired individuals

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Translational Neurodegeneration 2021年第1期10卷 126-139页

作者： k.k.Pin Ng Hui Chiew Pedro Rosa-Neto Nagaendran k.ndiah Zahinoor Ismail Serge gauthier Department of Neurology National Neuroscience InstituteSingaporeSingapore Duk.-NUS Medical School SingaporeSingapore Lee k.ng Chian School of Medicine-Imperial College London Nanyang Technological UniversitySingaporeSingapore The McGill University Research Centre for Studies in Aging MontrealCanada Hotchk.ss Brain Institute and Obrien Institute for Public Health/Departments of Psychiatry Clinical Neurosciencesand Community Health SciencesUniversity of CalgaryCalgaryAlbertaCanada

The development of in vivo biomark.rs of Alzheimer's disease(AD)has advanced the diagnosis of AD from a clinical syndrome to a biological *** preclinical stage of AD continuum is defined by the identification of AD biomark.rs crossing the pathological threshold in cognitively unimpaired *** neuropsychiatric symptoms(NPS)are non-cognitive symptoms that are increasingly recognized as early manifestations of AD,the associations of NPS with AD pathophysiology in preclinical AD remain ***,we review the associations between NPS and AD biomark.rs amyloid-(3(Aβ),tau and neurodegeneration in preclinical AD and cognitivelyunimpaired individuals in 19 eligible English-language publications(8 cross-sectional studies,10 longitudinal,1 both cross-sectional and longitudinal).The cross-sectional studies have consistently shown that NPS,particularly depressive and anxiety symptoms,are associated with higher Aβ.The longitudinal studies have suggested that greater NPS are associated with higher Aβ and cognitive decline in cognitively unimpaired subjects over ***,most of the studies have either cross-sectionally or longitudinally shown no association between NPS and tau *** the association of NPS and neurodegeneration,two studies have shown that the cerebrospinal fluid total-tau is link.d to longitudinal increase in NPS and that the NPS may predict longitudinal metabolic decline in preclinical AD,***,evidence for the association between atrophy and NPS in preclinical AD is less ***,future longitudinal studies with well-designed methodologies and NPS measurements are required not only to determine the relationship among AT(N)biomark.rs,NPS and cognitive decline,but also to elucidate the contribution of comorbid pathology to preclinical AD.

关键词： Neuropsychiatric symptoms Preclinical Alzheimer's disease Mild behavioral impairment Amyloid-β Hyperphosphorylated tau Neurodegeneration

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Preparation of Different Lights Irradiated ZnSe/GSH QDs and Their Interaction with BSA

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Journal of Wuhan University of Technology(Materials Science) 2019年第4期34卷 858-865页

作者：丁玲 HE Huan 李世迁 ZHOU Jin HUANG k.ntao CHENG Zhengzai gauthier Mario The State k.y Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology Wuhan 430081China Coal Conversion and New Carbon Materials Hubei k.y Laboratory School of Chnemistry and Chemical EngineeringWuhan University of Science and TechnologyWuhan 430081China k.y Laboratory of Measurement and Control System for Offshore Environment Fuqing Branch of Fujian Normal UniversityFuqing 350300China

Using L-glutathione(GSH) as a capping agent,Zn Se/GSH quantum dots(QDs) were prepared under microwave irradiation and irradiated under dark. ultraviolet light and incandescent light, respectively. The properties and interaction of different lights irradiated ZnSe/GSH QDs and bovine serum albumin(BSA) were studied systematically. The fluorescence(FL) spectra results reveal that the quenching mechanism are all the static quenching in nature. The quenching constant(k.v) and binding constant(k. value of different irradiated Zn Se/GSH QDs and BSA all increased with the change of light types from dark.to incandescent light and UV light. The number of binding site(n) is close to 1 at different temperatures. The lighting types influence the enthalpy and entropy changes. The Fourier transform infrared(FTIR) spectra indicate that the light induced GSH ligand will facilitate photocatalytic oxidation on the surface of ZnSe/GSH QDs. The circular dichroism(CD)results show that the α-helicity content of BSA decreases from 60.34%, 59.31%, to 58.79% under UV lighting,incandescent lighting and dark.conditions. The interaction results of different lights illuminated ZnSe/GSH QDs with BSA by CD spectra method matches well with that by FL and FTIR spectra. That is, the interaction of ZnSe/GSH QDs and BSA from strong to weak.is UV light, incandescent light and dark.in sequence.

关键词： lights irradiated ZnSe/GSH quantum dots preparation bovine serum albumin interaction thermodynamics

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Prevention strategies for Alzheimer’s disease

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Translational Neurodegeneration 2012年第1期1卷 99-102页

作者： Serge gauthier Liyong Wu Pedro Rosa-Neto Jianping Jia McGill Center for studies in Aging McGill UniversityMontrealCanada Neurological Department Xuanwu HospitalCapital UniversityBeijingChina McGill Centre for Studies in Aging(MCSA) McGill University6825Boul.LaSalle BlvdMontrealQC H4H 1R3Canada

Symptomatic treatment during the dementia stage of Alzheimer’s disease(AD)cannot delay or halt the progression of this ***,prevention in the preclinical stage is lik.ly the most effective way to decrease the incidence of this age-associated neurodegenerative condition,and its associated burden for individuals and ***,gender,family history,ApoE4,systolic blood pressure,body mass index,total cholesterol level and physical activity are all used as component of dementia risk.*** have been numerous challenges in conducting primary prevention trials in *** strategies for prevention studies include studying those subjects with more risk.factors for AD,such as older age,those with a positive family history of late onset AD,and those who are ApoE4 *** of these strategies is designed to increase the probability of developing AD thereby decreasing the sample size or the duration of follow *** strategy would be to target directly the pathophysiology of AD in its preclinical stages and use the biomark.rs in prevention trial as surrogate *** will be done first in carriers of dominantly inherited early onset *** this research tak.s place network. of memory clinics must prepare to transfer new k.owledge to persons interested in a preventive approach to AD.

关键词： Alzheimer disease Risk.factor Prevention Clinical trial Clinical practice

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Investigation of a cyanine dye assay for the evaluation of the biocompatibility of magnesium alloys by direct and indirect methods

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Bioactive Materials 2020年第1期5卷 26-33页

作者： Afrah Al Hegy Ryan Smith Eric R.gauthier Joy E.Gray-Munro Dept.of Chemistry and Biochemistry Laurentian UniversitySudburyOntarioP3E 2C6Canada

Magnesium and its alloys are promising candidates for a new generation of biodegradable metals in orthopaedic applications due to their excellent biocompatibility,biodegradability,and mechanical properties that are similar to natural ***,direct in vitro assessment of these materials in the presence of cells is complicated by degradation products from the alloy that lead to a false positive for the most commonly used cell adhesion and cell proliferation *** this paper,a cyanine dye was used to quantitatively evaluate the in vitro biocompatibility of a Mg AZ31 alloy by both direct and indirect *** cytotoxicity of the corrosion products was evaluated via an indirect method;a 25%decrease in cell viability compared to control samples was ***,direct assessment of cell adhesion and proliferation showed a statistically significant increase in cell number at the surface after 72 *** addition,the degradation rate and surface characteristics of the Mg AZ31 alloy were evaluated for both direct and indirect *** degradation rate was unaffected by the presence of cells while evidence of an increase in calcium phosphate deposition on the magnesium alloy surface in the presence of cells was *** study demonstrates that a cyanine dye based assay provides a more accurate assessment of the overall in vitro biocompatibility of biodegradable metals than the more commonly used assays reported in the literature to date.

关键词： Magnesium alloys Biocompatibility Direct method Indirect method Cyanine dye Cell adhesion Cell proliferation Cytotoxicity

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