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The functional properties of synapses made by reg.nerated axons across spinal cord lesion sites in lamprey

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Neural Reg.neration Research 2022年第10期17卷 2272-2277页

作者： david parker Department of Physiolog. Developmentand NeuroscienceUniversity of CambridgeCambridgeUK

While the anatomical properties of reg.nerated axons across spinal cord lesion sites have been studied extensively,little is known of how the functional properties of reg.nerated synapses compared to those in unlesioned animals.This study aims to compare the properties of synapses made by reg.nerated axons with unlesioned axons using.the lamprey,a model system for spinal injury research,in which functional locomotor recovery after spinal cord lesions is associated with axonal reg.neration across the lesion site.Reg.nerated synapses below the lesion site did not differ from synapses from unlesioned axons with respect to the amplitude and duration of sing.e excitatory postsynaptic potentials.They also showed the same activity-dependent depression over spike trains.However,reg.nerated synapses did differ from unlesioned synapses as the estimated number of synaptic vesicles was g.eater and there was evidence for increased postsynaptic quantal amplitude.For axons above the lesion site,the amplitude and duration of sing.e synaptic inputs also did not differ sig.ificantly from unlesioned animals.However,in this case,there was evidence of a reduction in release probability and inputs facilitated rather than depressed over spike trains.Synaptic inputs from sing.e reg.nerated axons below the lesion site thus do not increase in amplitude to compensate for the reduced number of descending.axons after functional recovery.However,the postsynaptic input was maintained at the unlesioned level using.different synaptic properties.Conversely,the facilitation from the same initial amplitude above the lesion site made the synaptic input over spike trains functionally strong.r.This may help to increase propriospinal activity across the lesion site to compensate for the lesion-induced reduction in supraspinal inputs.The animal experiments were approved by the Animal Ethics Committee of Cambridg. University.

关键词： electrophysiolog. lamprey plasticity reg.neration reticulospinal axon spinal cord spinal injury synapse

Proximate analyses, in vitro antioxidant activity and g.-MS analyses of fermented Pentaclethra macrophylla seeds

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Life Research 2024年第3期7卷 2-8页

作者： Ikechukwu Okoro parker Joshua Innocent Okag. Christian Amah Nnamani Ikenna Nene Chiaka-Onyemeze Emeka Anaduaka david Obasi Prince Okoroh Daniel Orieke Victor Og.g.a Department of Medical Biochemistry College of Health SciencesDavid Umahi Federal University of Health SciencesUburuNigeria Department of Biochemistry University of NigeriaNsukkaNigeria Department of Biochemistry State University of Medical and Applied SciencesIgbo-EnoNigeria Department of Medical Laboratory Sciences State University of Medical and Applied SciencesIgbo-EnoNigeria

The present study assessed the proximate composition,in vitro antioxidant activity and g.-MS analyses of fermented Pentaclethra macrophylla seeds extract(FPMSE).The in vitro antioxidant activity was assessed using.2,2-diphenyl-1-picrylhydrazl(DPPH)while g.s Chromatog.aphy-Mass Spectrophotometry(g.-MS)technique was used to identify the volatile compounds in FPMSE.FPMSE revealed a dose dependent percentag. inhibition of the extract on DPPH assay.Proximate composition of FPMSE constitutes respectively;ash(0.33±0.12%),protein(2.19±0.08%),fats and oil(80.60±0.00%),carbohydrate(16.88±0.00%)while moisture and fibre were not detected.However,the pulverised sample constitute respectively;ash(1.27±0.58%),protein(10.51±0.60%),moisture(8.27±0.12%),fats and oil(32.33±0.12%),fibre(7.27±0.12%)and carbohydrate(40.35±0.00%).g.-MS analyses revealed fourteen(14)fatty acids including.Octadecanoic acid(1.95%),Benzyloxymethylimine(43.89%),2-Allylpent-4-enoic acid benzyl ester(26.25%),Hexadecanoic acid,methyl ester(1.09%),Oleic Acid(0.25%),9,12-Octadecadienoic acid,methyl ester(Omeg.-6-fatty acid)(1.52%).The bioactive compounds identified in FPMSE could contribute to the pharmacolog.cal properties of P.macrophylla seeds and hence,could be of considerable interest for the development of new drug..

关键词： Pentaclethra macrophylla in vitro antioxidant g.-MS fatty acids

Functional chang.s after spinal lesions: implications for interventions

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Neural Reg.neration Research 2018年第5期13卷 811-812页

作者： david parker Department of Physiolog. Neuroscience and DevelopmentUniversity of Cambridge

We have known for many years that the spinal cord can g.nerate some basic locomotor outputs under specific experimental conditions without any input from the brain or the periphery（Stuart and Hultborn,2008）.However,when inputs from the brain are lost following.spinal cord injury（SCI）,the mammalian spinal cord is unable to g.nerate normal,g.al-directed locomotor outputs.

关键词： Functional chang.s after spinal lesions implications for interventions

Positron emission particle tracking.—Application and labelling.techniques

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Particuolog. 2008年第1期6卷 16-23页

作者： david J. parker School of Physics and Astronomy the University of Birmingham Edgbaston Birmingham B15 2TT UK

The positron emission particle tracking.（PEPT） technique has been widely used in science and eng.neering.to obtain detailed information on the motion and flow fields of fluids or g.anular materials in multiphase systems, for example, fluids in rock cracks, chemical reactors and food processors; dynamic behaviour of g.anular materials in chemical reactors, g.anulators, mixers, dryers, rotating.kilns and ball mills. The information obtained by the PEPT technique can be used to optimise the desig., operational conditions for a wide rang. of industrial process systems, and to evaluate modelling.work. The technique is based on tracking.radioactively labelled particles （up to three particles） by detecting.the pairs of backto-back 511 keV γ-rays arising.from annihilation of emitted positrons. It therefore involves a positron camera, location alg.rithms for calculating.the tracer location and speed, and tracer labelling.techniques. This paper will review the particle tracking.technique from tracking.alg.rithm, tracer labelling.to their application.

关键词： PEPT Tracer Alg.rithm Tracking

Neuromodulator interactions and spinal cord injury in lamprey

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Neural Reg.neration Research 2018年第4期13卷 643-644页

作者： david parker Thomas J.McClelland Department of Physiolog. Neuroscience and DevelopmentUniversity of Cambridge

Neuromodulation is mediated by neurotransmitters that typically act on g.protein-coupled receptors.It can confer behavioural flexibility by modifying.the functional properties of anatomically hard-wired neural circuits.Sing.e neuromodulators g.nerally have diverg.nt cellular and synaptic effects（Harris-Warrick and Johnson,2010）,and different modulators,

关键词： Fig.re Neuromodulator interactions and spinal cord injury in lamprey

First principles insig.ts into oxide/polymer composites: SrTiO_(3) /polyaniline/g.aphene

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Journal of Materials Science & Technolog. 2023年第35期166卷 250-260页

作者： Nathan D.Wood Joshua S.Tse Jonathan M.Skelton david J.Cooke Lisa J.g.llie Stephen C.parker Marco Molinari Department of Chemical Sciences School of Applied SciencesUniversity of HuddersfieldHuddersfield HD13DHUK Department of Chemistry University of ManchesterManchester M139PLUK Department of Chemistry University of BathBath BA27AYUK

A detailed computational investig.tion,based on density functional theory,of the interaction of polyani-line(PANI)and g.aphene nanoribbons(g.Rs)with SrTiO_(3) is presented.The adsorption of PANI in var-ious oxidation states and co-adsorption with g.Rs is found to be thermodynamically favourable.Ad-sorbed PANI introduces N and C 2p states into the SrTiO_(3) bandg.p,while co-adsorption of PANI and g.Rs leads to a bridg.ng.of the g.p and semi-metallic behaviour,thus rendering.the electrical properties hig.ly sensitive to the loading.of the g.Rs/PANI in the composites.Modelling.the lattice dynamics of the composites predicts a 68-88%reduction in the lattice thermal conductivity due to reduced phonon g.oup velocities.Taken tog.ther,these finding. provide insig.t into the g.owing.number of experimental studies hig.lig.ting.the enhanced thermoelectric performance of oxide-polymer composites and indicate co-adsorption with g.aphene as a facile direction for future research.

关键词： Polymer/inorg.nic composites Polyaniline/strontium titanate/g.aphene nanoribbon composites PANI/g.R/SrTiO_(3)composites Thermoelectric composites Electrical transport Thermal conductivity1 Introduction

Positron imag.ng.systems for studying.particulate, g.anular and multiphase flows

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Particuolog. 2012年第2期10卷 146-153页

作者： Thomas W.Leadbeater david J.parker Joseph g.rg.uli Positron Imag.ng.Centre University of BirminghamEdgbastonBirmingham B152TTUKa

The University of Birming.am has pioneered and adapted the use of the medical imag.ng.technique known as positron emission tomog.aphy （PET） to the study of particulate, g.anular and multiphase flows in industrial and physical processes, This paper provides a review of the PET and complimentary positron emission particle tracking.（PEPT） techniques and details their application to the study of particulate sys- tems, The current state of the art, recent developments and example results from many of the applications to which these techniques have been applied are hig.lig.ted.

关键词： Positron emission particle tracking.（PEPT）Particle dynamicsMulti-phase flow measurement

The role of seaweed as a potential dietary supplementation for enteric methane mitig.tion in ruminants: Challeng.s and opportunities

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Animal Nutrition 2021年第4期7卷 1371-1387页

作者： Byeng.R.Min david parker david Brauer Heidi Waldrip Catherine Lockard Kristin Hales Alexia Akbay Simona Aug.te Colleg. of Ag.iculture Environment and Nutrition SciencesTuskegee UniversityTuskegeeAL 36088USA United States Department of Ag.iculture(USDA) Agriculture Research Service(ARS)2300 Experiment Station Dr.BushlandTX 79012USA Department of Animal and Food Sciences Texas Tech UniversityLubbockTX 79409USA Symbrosia Inc Kailua-KonaHI 96740USA

Seaweeds are macroalg.e,which can be of many different morpholog.es,sizes,colors,and chemical profiles.They include brown,red,and g.een seaweeds.Brown seaweeds have been more investig.ted and exploited in comparison to other seaweed types for their use in animal feeding.studies due to their larg. sizes and ease of harvesting.Recent in vitro and in vivo studies sug.est that plant secondary compound-containing.seaweeds(e.g.,halog.nated compounds,phlorotannins,etc.)have the potential to mitig.te enteric methane(CH_(4))emissions from ruminants when added to the diets of beef and dairy cattle.Red seaweeds including.Asparag.psis spp.are rich in crude protein and halog.nated compounds compared to brown and g.een seaweeds.When halog.nated-containing.red seaweeds are used as the active ing.edient in ruminant diets,bromoform concentration can be used as an indicator of antimethanog.nic properties.Phlorotannin-containing.brown seaweed has also the potential to decrease CH_(4) production.However,numerous studies examined the possible anti-methanog.nic effects of marine seaweeds with inconsistent results.This work reviews existing.data associated with seaweeds and in vitro and in vivo rumen fermentation,animal performance,and enteric CH4 emissions in ruminants.Increased understanding.of the seaweed supplementation related to rumen fermentation and its effect on animal performance and CH_(4) emissions in ruminants may lead to novel strateg.es aimed at reducing.g.eenhouse g.s emissions while improving.animal productivity.

关键词： Seaweed Bromoform Methane Phlorotannins Ruminant Cattle

Dietary mitig.tion of enteric methane emissions from ruminants:A review of plant tannin mitig.tion options

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Animal Nutrition 2020年第3期6卷 231-246页

作者： Byeng.R.Min Sandra Solaiman Heidi M.Waldrip david parker Richard W.Todd david Brauer United States Department of Ag.iculture(USDA) Agricultural Research Service(ARS)BushlandTX79012USA Tuskeg.e University TuskegeeAL36088USA

Methane g.s from livestock production activities is a sig.ificant source of g.eenhouse g.s(g.g.emissions which have been shown to influence climate chang..New technolog.es offer a potential to manipulate the rumen biome throug. g.netic selection reducing.CH4 production.Methane production may also be mitig.ted to varying.deg.ees by various dietary intervention strateg.es.Strateg.es to reduce g.g.emissions need to be developed which increase ruminant production efficiency whereas reducing.production of CH4 from cattle,sheep,and g.ats.Methane emissions may be efficiently mitig.ted by manipulation of natural ruminal microbiota with various dietary interventions and animal production efficiency improved.Althoug. some CH4 abatement strateg.es have shown efficacy in vivo,more research is required to make any of these approaches pertinent to modern animal production systems.The objective of this review is to explain how anti-methanog.nic compounds(e.g.,plant tannins)affect ruminal microbiota,reduce CH4 emission,and the effects on host responses.Thus,this review provides information relevant to understanding.the impact of tannins on methanog.nesis,which may provide a cost-effective means to reduce enteric CH4 production and the influence of ruminant animals on g.obal g.g.emissions.

关键词： Feed efficiency g.eenhouse g.s(g.g.emission Methanog.nesis Tannin Ruminant