检索结果-南通市图书馆

Combining neural progenitor cell transplant and rehabilitation for enhanced recovery after cervical spinal cord injury

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第7期19卷 1433-1434页

作者： camila m.Freria Paul Lu Department of Neurosciences University of CaliforniaSan DiegoLa JollaCAUSA Veterans Administration San Diego Healthcare System San DiegoCAUSA

Efforts to promote recovery of function after human spinal cord injury(SCI) will likely require interventions to rgeting the corticospinal tract(CSt) motor system:the most important pathway for voluntary motor control in *** system has historically been the most refractory to regenerative efforts after *** "nonregeneration" of the CSt changed when robust regeneration of the CSt into spared tissue was demonstrated by the inactivation of phosphatase and tensin homolog and delivery of inosine.

关键词： cervical progenitor injury

Chromatin condensation but not DNA integrity of pig sperm is greater in the sperm-rich fraction

在线全文

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2024年第1期15卷 171-181页

作者： Estel Viñolas-Vergés Jordi Ribas-maynou Isabel Barranco camila Peres Rubio Sergi Bonet Jordi Roca marc Yeste Unit of Cell Biology Department of BiologyFaculty of SciencesUniversity of GironaGironaSpain Biotechnology of Animal and Human Reproduction(technoSperm) Institute of Food and Agricultural TechnologyUniversity of GironaGironaSpain Department of medicine and Animal Surgery Faculty of Veterinary ScienceUniversity of MurciaMurciaSpain Catalan Institution for Research and Advanced Studies(ICREA) S08010 BarcelonaSpain

Background Protamination and condensation of sperm chromatin as well as DNA integrity play an essential role during fertilization and embryo *** some mammals,like pigs,ejaculates are emitted in three separate fractions:pre-sperm,sperm-rich(SRF)and post sperm-rich(PSRF).these fractions are known to vary in volume,sperm concentration and quality,as well as in the origin and composition of seminal plasma(SP),with differences being also observed within the SRF ***,whether disparities in the DNA integrity and chromatin condensation and pro-tamination of their sperm exist has not been *** this study determined chromatin protamination(Chromomycin A3 test,CmA_(3)),condensation(Dibromobi-mane test,DBB),and DNA integrity(Comet assay)in the pig sperm contained in the first 10 m L of the SRF(SRF-P1),the remaining portion of the sperm-rich fraction(SRF-P2),and the post sperm-rich fraction(PSRF).While chromatin protamination was found to be similar between the different ejaculate fractions(P>0.05),chromatin condensation was seen to be greater in SRF-P1 and SRF-P2 than in the PSRF(P=0.018 and P=0.004,respectively).Regarding DNA integrity,no differences between fractions were observed(P>0.05).As the SRF-P1 has the highest sperm concentra-tion and ejaculate fractions are known to differ in antioxidant composition,the oxidative stress index(OSi)in SP,calcu-lated as total oxidant activity divided by total antioxidant capacity,was tested and confirmed to be higher in the SRF-P1 than in SRF-P2 and PSRF(0.42±0.06 vs.0.23±0.09 and 0.08±0.00,respectively;Pthis index,in addition,was observed to be correlated to the sperm concentration of each fraction(Rs=0.973;Pm DNA integrity was not found to differ between ejaculate fractions,SRF-P1 and SRF-P2 were observed to exhibit greater chromatin condensation than the *** could be related to the OSi of each fraction.

关键词： Chromatin Condensation DNA integrity Ejaculate fractions Pig Protamination Sperm

QCD sum rule study of J^(P)=1^(±)exotic states with two heavy quarks in the molecular picture

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第6期48卷 31-37页

作者： t.m.Aliev S.Bilmis m.Savcı Department of Physics Middle East Technical UniversityAnkara06800Turkey tUBItAK ULAKBIm Ankara06510Turkey

In this study,the spectroscopic parameters of exotic molecular states composed of mesons containing two heavy quarks(scalar-axial and pseudoscalar-axial meson combinations)are investigated within the QCD sum *** findings reveal that molecular states containing charm quarks do not form bound states,whereas states with b-quarks can form exotic molecular *** observation has significant implications for understanding the structure of these exotic states.

关键词： QCD sum rules exotic mesons molecular states

Analysis of strong decays of SU(3)partners ofΩ(2012)baryon

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第8期48卷 34-41页

作者： t.m.Aliev S.Bilmis m.Savci Department of Physics Middle East Technical UniversityAnkara 06800Turkey tUBItAK ULAKBIm Ankara 06510Turkey

We estimate the coupling constants and decay widths of the SU(3)partners of theΩ(2012)hyperon,as discovered by the BELLE Collaboration,using the distribution amplitudes of the octet baryons within the light cone sum rules *** study includes a comparison of the obtained results for the relevant decay widths with those derived within the framework of the flavor SU(3)*** observe a good agreement between the predictions of both ***,our result on the decay width ofΩ→ΞK is compatible with the existing experimental result within the uncertainties of the model *** results can provide helpful insights for determining the nature of the SU(3)partners of theΩ(2012)baryon.

关键词： coupling constants light cone sum rule hyperon

Distribution, health and ecological risk assessments of trace elements in Nigerian oil sands

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2024年第1期43卷 59-71页

作者： Odunayo t.Ore Festus m.Adebiyi Department of Chemistry Obafemi Awolowo UniversityIle-Ife 220005Nigeria Department of Chemical Sciences Achievers UniversityOwoNigeria

the Nigerian oil sands represent the largest oil sand deposit in Africa, yet there is little published information on the distribution and potential health and ecological risks of trace elements in the oil resource. In the present study, we investigated the distribution pattern of 18trace elements(including biophile and chalcophile elements) as well as the estimated risks associated with exposure to these elements. the results of the study indicated that Fe was the most abundant element, with a mean concentration of 22,131 mg/kg while Br had the lowest mean concentration of 48 mg/kg. the high occurrence of Fe and ti suggested a possible occurrence of ilmenite(Fe tiO_(3)) in the oil sands. Source apportionment using positive matrix factorization showed that the possible sources of detected elements in the oil sands were geogenic, metal production, and crustal. the contamination factor, geo-accumulation index, modified degree of contamination, pollution load index, and Nemerow pollution index indicated that the oil sands are heavily polluted by the elements. Health risk assessment showed that children were relatively more susceptible to the potentially toxic elements in the oil sands principally via ingestion exposure route(HQ > 1E-04). Cancer risks from inhalation are unlikely due to CR t ingestion and dermal contact pose severe risks(CR > 1E-04). the high concentrations of the elements pose serious threats due to the potential for atmospheric transport, bioaccessibility, and bioavailability.

关键词： Biophile Chalcophile Oil sand Risk assessment trace element

tensile deformation of fine-grained mg at 4K,78K and 298K

在线全文

学校读者我要写书评

暂无评论

Journal of magnesium and Alloys 2024年第6期12卷 2534-2556页

作者： m.Walag A.Kula P.Noga t.tokarski G.Cios m.Niewczas AGH University of Krakow Faculty of Non-Ferrous MetalsKrakowPoland AGH University of Krakow Academic Centre for Materials and NanotechnologyKrakowPoland materials Science and Engineering McMaster UniversityHamiltonCanada

the impact of grain size, ranging from 0.9 μm to 9 μm, on the mechanical properties of commercially pure mg is investigated at temperatures of 4K, 78K, and 298K. the mechanisms governing plastic flow are influenced by both grain size and temperature. At 4K and 78K, dominant deformation modes in mg involve dislocation glide and extension twinning, regardless of grain size. the interactions between basal and non-basal dislocations and dislocations with grain boundaries promote an unusually high rate of work hardening in the plastic regime, leading to premature failure. the yield stress follows the Hall-Petch relationship σy~ k/√d, with the slope k increasing with decreasing temperature. At 298K, in addition to dislocation glide and twinning, grain boundary sliding(GBS) becomes significant in samples with grain sizes below 3 μm, considerably enhancing the material's deformability. GBS activation provides an additional recovery mechanism for dislocations accumulating at grain boundaries, facilitating their absorption during sliding and rotation. Analysis of σ Θ relationship suggests that the basal slip is the dominant dislocation mode in mg at 298K. Decreasing grain size suppresses dislocation activity and twinning and increases GBS, resulting in lower Θ and σ Θ values. Suppressing conventional deformation modes coupled with enhanced GBS yields stress softening, breaking down the Hall-Petch relationship in mg below 3 μm grain size, leading to an inverse Hall-Petch behaviour. the work reports new data on the strength, ductility, work hardening and fracture behaviour, and their variations with mg grain size across different temperature regimes.

关键词： Polycrystalline mg mechanical properties Deformation mechanisms Work-hardening texture evolution Cryogenic temperatures Hall-Petch relationship

Long-term monitoring reveals the effect of precipitation and silviculture on Nothofagus regeneration in Northern Patagonia mixed forests

在线全文

学校读者我要写书评

暂无评论

Ecological Processes 2024年第2期13卷 103-117页

作者： Georgina Sola camila mateo Alejandro Dezzotti Paula marchelli Hernán Attis Beltrán Renato Sbrancia Luis Chauchard marcelo González Pe?alba martín Lara Verónica El mujtar Consejo Nacional de Investigaciones Científicas y técnicas (CONICEt ) Asentamiento Universitario San martín de los Andes (AUSmA-UNCo) Instituto de Investigaciones Forestales y Agropecuarias Bariloche (IFAB) Instituto Nacional de Tecnología Agropecuaria (INTA) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Departamento de Conservación y manejo Parque Nacional Lanín- Administración de Parques Nacionales (PNL-APN)

Background tree regeneration is a key component of resilience because it promotes post-disturbance recovery of forests. Northwestern Patagonia from Argentina is occupied by Nothofagus alpina（Na）, N. obliqua（No）, and N. dombeyi（Nd） forests that grow along an intense precipitation gradient, managed throughout shelterwood silvicultural system by technicians of the Lanin Natural Reserve. the objective of this study was to evaluate the influence of seeding cuttings over the dynamics of Nothofagus mixed forests across landscape（precipitation gradient） based mainly on the composition and abundance of tree regeneration, permanent sampling plots and generalized linear mixed models. In particular, we analysed:（i） the structure of sexual and asexual regeneration during 20 years after harvest（the dynamics of managed forests）, and（ii） the structure of sexual regeneration in primary and managed forests after > 20 years of harvest（the effect of silviculture）.Results Nd was the most abundant species in the regeneration of managed forests during all periods in both sites despite its lower contribution to the adult cohort. During the 10–20 years period after harvest, the humid site exhibited higher regeneration density than the mesic site(120,000 and 6000 ind ha-1, respectively), and it decreased afterwards. the number of established regeneration（> 2 m height） was lower for Na in the mesic site and for No in the humid site(0 and 57 ind ha-1, respectively). However, in comparison to No, Na showed a higher number of sprouted stumps and sprouts per stump, and a higher sprout height in the mesic site. No exhibited higher sprout mortality in the humid site. Finally, the regeneration of primary forests showed lower density and height, and a more balanced composition than that of managed *** the silvicultural effects on the mixed forest regeneration dynamics was strongly influenced by the condition of sites. therefore, management prescriptions should be adj

关键词： Nothofagus alpina Nothofagus obliqua Nothofagus dombeyi Basal sprouting Shelterwood silvicultural system Ecological resilience

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

美国页岩油气地质特征及勘探开发进展

石油勘探与开发 2024年第4期51卷 807-828页

作者： mCmAHON t P LARSON t E ZHANG t SHUStER m 美国德克萨斯大学奥斯汀分校杰克逊地质科学学院经济地质局奥斯汀78758-4445德克萨斯州美国

基于美国页岩油气勘探开发历程的回顾,对主要页岩盆地的地质演化、主要页岩层系的油气地质特征及勘探开发进展进行系统梳理和总结。美国重要页岩盆地的富烃页岩主要发育于6个地质时期:中奥陶世、中—晚泥盆世、早石炭世(中—晚密西西比... 详细信息

基于美国页岩油气勘探开发历程的回顾,对主要页岩盆地的地质演化、主要页岩层系的油气地质特征及勘探开发进展进行系统梳理和总结。美国重要页岩盆地的富烃页岩主要发育于6个地质时期:中奥陶世、中—晚泥盆世、早石炭世(中—晚密西西比世)、早二叠世、晚侏罗世和晚白垩世(塞诺曼期—土伦期),构造沉积环境主要包括克拉通内盆地、前陆盆地和被动大陆边缘盆地。古生界富烃页岩主要分布于以下6个盆地:阿巴拉契亚盆地(尤蒂卡页岩和马塞勒斯页岩)、阿纳达科盆地(伍德福德页岩)、威利斯顿盆地(巴肯页岩)、阿卡马盆地(费耶特维尔页岩)、沃思堡盆地(巴内特页岩)和二叠盆地(狼营组和斯帕瑞组/骨泉组页岩)。中生界富烃页岩主要发育在西墨西哥湾盆地(海恩斯维尔组和鹰滩组)和落基山盆地群(以丹佛和粉河盆地的尼尔布拉勒组页岩为主)。通过对各页岩区带的详细分析发现,页岩的岩相和矿物成分存在差异,“页岩储层”并非只是页岩,很多情况下页岩油气还产自粉砂岩和碳酸盐岩等多种岩石类型。美国的页岩油气资源丰富,页岩油地质资源量超过0.246×1012 t,页岩气地质资源量超过290×1012 m3。在开启“页岩革命”的水平井水力压裂技术出现之前,美国经过了长达20年的勘探开发实践和理论技术积累。自2007年至2023年,美国页岩油气产量从约11.2×104t/d油当量增加到超过300.0×104t/d油当量,2017年页岩油气产量超过了常规油气,2023年在油气总产量中的占比增加到60%以上。页岩油气的开发主要得益于钻完井技术的改进,“立体开发”的攻关,以及重复压裂、提高原油采收率和“U”形井等技术的应用。基于美国丰富的页岩资源基础和技术的不断进步,页岩油气的产量将继续为全美的油气生产做出更大贡献。

关键词：美国页岩油页岩气页岩储层非常规储层油气产量资源评价

Aerodynamics of a tandem-Bladed Axial Compressor Rotor under Circumferential Distortion at Different Rotational Speeds

在线全文

学校读者我要写书评

暂无评论

Journal of thermal Science 2024年第4期33卷 1340-1356页

作者： Amit KUmAR Jerry t.JOHN A.m.PRADEEP R.A.DAKKERmANS Dragan KOZULOVIC Department of Aerospace Engineering Indian Institute of Technology BombayMumbai400076India Department of Automotive and Aeronautical Engineering Hamburg University of Applied Sciences20099HamburgGermany Institute of Jet Propulsion Bundeswehr University Munich85577NeubibergGermany

For most aircraft engines,inflow distortion is *** distortion is known to degrade the aerodynamic performance and stable operating limits of a *** rotor configuration is an arrangement that effectively controls the growth of the boundary layer over the suction surface of the ***,a higher total pressure rise can be achieved through this unconventional design approach involving the splitting of the blade into forward and aft *** is expected that the effect of inlet flow distortion would be more severe for a tandem-rotor design due to the greater flow turning inherent in such ***,this aspect needs to be thoroughly *** present study discusses the effect of circumferential distortion on the tandem-rotor at different rotational ***-annulus RANS simulations using ANSYS CFX are used in the present *** performance of the rotor at a particular flow coefficient and different rotational speeds is *** total pressure and efficiency are observed to drop at lower mass flow rates under the influence of circumferential *** loss region in each blade passage is mainly associated with the blade wake,tip leakage vortex,secondary flow,and boundary ***,their contribution varies from passage to passage,particularly in the distorted *** the lower span,the wake width is found to be higher than that at a higher *** to the redistribution of the mass flow,the circumferential extent reduces at a higher *** the undistorted sector,the strength of the tip leakage vortex is significantly higher at the design rotational speed than at lower *** distortion near the tip region promotes an early vortex breakdown even at the design operating *** adversely affects the total pressure,efficiency,and stall *** clean flow conditions,this phenomenon is only observed near the stall *** the design operating condition,the breakdown of the forward rotor tip l

关键词： tandem rotor circumferential distortion loss tip leakage vortex vortex breakdown diffusion factor aerodynamics of compressor blade