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Changes in neurological and pathological outcomes in a modified rat spinal cord injury model with closed canal 预览
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作者 Xin Sun Xing-Zhen Liu +4 位作者 Jia Wang Hai-Rong Tao Tong Zhu Wen-Jie Jin Kang-Ping Shen 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第4期697-704,共8页
Most animal spinal cord injury models involve a laminectomy,such as the weight drop model or the transection model.However,in clinical practice,many patients undergo spinal cord injury while maintaining a relatively c... Most animal spinal cord injury models involve a laminectomy,such as the weight drop model or the transection model.However,in clinical practice,many patients undergo spinal cord injury while maintaining a relatively complete spinal canal.Thus,open spinal cord injury models often do not simulate real injuries,and few previous studies have investigated whether having a closed spinal canal after a primary spinal cord injury may influence secondary processes.Therefore,we aimed to assess the differences in neurological dysfunction and pathological changes between rat spinal cord injury models with closed and open spinal canals.Sprague-Dawley rats were randomly divided into three groups.In the sham group,the tunnel was expanded only,without inserting a screw into the spinal canal.In the spinal cord injury with open canal group,a screw was inserted into the spinal canal to cause spinal cord injury for 5 minutes,and then the screw was pulled out,leaving a hole in the vertebral plate.In the spinal cord injury with closed canal group,after inserting a screw into the spinal canal for 5 minutes,the screw was pulled out by approximately 1.5 mm and the flat end of the screw remained in the hole in the vertebral plate so that the spinal canal remained closed;this group was the modified model,which used a screw both to compress the spinal cord and to seal the spinal canal.At 7 days post-operation,the Basso-Beattie-Bresnahan scale was used to measure changes in neurological outcomes.Hematoxylin-eosin staining was used to assess histopathology.To evaluate the degree of local secondary hypoxia,immunohistochemical staining and western blot assays were applied to detect the expression of hypoxia-inducible factor 1α(HIF-1α)and vascular endothelial growth factor(VEGF).Compared with the spinal cord injury with open canal group,in the closed canal group the Basso-Beattie-Bresnahan scores were lower,cell morphology was more irregular,the percentage of morphologically normal neurons was lower,the percentages of HIF-1α-and VEGF-immunorea 展开更多
关键词 Basso-Beattie-Bresnahan scores CLOSED SPINAL CANAL HIF-1α hypoxia MODEL nerve regeneration open SPINAL CANAL rat secondary INJURY SPINAL cord INJURY VEGF
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Effects of neural stem cell transplantation on the motor function of rats with contusion spinal cord injuries:a meta-analysis 预览
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作者 Kai Qian Tuo-Ye Xu +7 位作者 Xi Wang Tao Ma Kai-Xin Zhang Kun Yang Teng-Da Qian Jing Shi Li-Xin Li Zheng Wang 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第4期748-758,共11页
Objective:To judge the efficacies of neural stem cell(NSC)transplantation on functional recovery following contusion spinal cord injuries(SCIs).Data sources:Studies in which NSCs were transplanted into a clinically re... Objective:To judge the efficacies of neural stem cell(NSC)transplantation on functional recovery following contusion spinal cord injuries(SCIs).Data sources:Studies in which NSCs were transplanted into a clinically relevant,standardized rat model of contusion SCI were identified by searching the PubMed,Embase and Cochrane databases,and the extracted data were analyzed by Stata 14.0.Data selection:Inclusion criteria were that NSCs were used in in vivo animal studies to treat contusion SCIs and that behavioral assessment of locomotor functional recovery was performed using the Basso,Beattie,and Bresnahan lo-comotor rating scale.Exclusion criteria included a follow-up of less than 4 weeks and the lack of control groups.Outcome measures:The restoration of motor function was assessed by the Basso,Beattie,and Bresnahan locomotor rating scale.Results:We identified 1756 non-duplicated papers by searching the aforementioned electronic databases,and 30 full-text articles met the inclusion criteria.A total of 37 studies reported in the 30 articles were included in the meta-analysis.The meta-analysis results showed that transplanted NSCs could improve the motor function recovery of rats following contusion SCIs,to a moderate extent(pooled standardized mean difference(SMD)=0.73;95%confidence interval(CI):0.47–1.00;P<0.001).NSCs obtained from different donor species(rat:SMD=0.74;95%CI:0.36–1.13;human:SMD=0.78;95%CI:0.31–1.25),at different donor ages(fetal:SMD=0.67;95%CI:0.43–0.92;adult:SMD=0.86;95%CI:0.50–1.22)and from different origins(brain-derived:SMD=0.59;95%CI:0.27–0.91;spinal cord-derived:SMD=0.51;95%CI:0.22–0.79)had similar efficacies on improved functional recovery;however,adult induced pluripotent stem cell-derived NSCs showed no significant efficacies.Furthermore,the use of higher doses of transplanted NSCs or the administration of immunosuppressive agents did not promote better locomotor function recovery(SMD=0.45;95%CI:0.21–0.70).However,shorter periods between the contusion induction and the NSC tr 展开更多
关键词 Basso Beattie and Bresnahan locomotor rating scale CELL TRANSPLANTATION META-ANALYSIS motor functional recovery NEURAL regeneration NEURAL stem CELL NEURAL stem CELL TRANSPLANTATION rat model SPINAL CONTUSION SPINAL cord injury
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Web3D Learning Framework for 3D Shape Retrieval Based on Hybrid Convolutional Neural Networks
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作者 Wen Zhou Jinyuan Jia +1 位作者 Chengxi Huang Yongqing Cheng 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2020年第1期93-102,共10页
With the rapid development of Web3 D technologies, sketch-based model retrieval has become an increasingly important challenge, while the application of Virtual Reality and 3 D technologies has made shape retrieval of... With the rapid development of Web3 D technologies, sketch-based model retrieval has become an increasingly important challenge, while the application of Virtual Reality and 3 D technologies has made shape retrieval of furniture over a web browser feasible. In this paper, we propose a learning framework for shape retrieval based on two Siamese VGG-16 Convolutional Neural Networks(CNNs), and a CNN-based hybrid learning algorithm to select the best view for a shape. In this algorithm, the AlexNet and VGG-16 CNN architectures are used to perform classification tasks and to extract features, respectively. In addition, a feature fusion method is used to measure the similarity relation of the output features from the two Siamese networks. The proposed framework can provide new alternatives for furniture retrieval in the Web3 D environment. The primary innovation is in the employment of deep learning methods to solve the challenge of obtaining the best view of 3 D furniture,and to address cross-domain feature learning problems. We conduct an experiment to verify the feasibility of the framework and the results show our approach to be superior in comparison to many mainstream state-of-the-art approaches. 展开更多
关键词 WEB3D sketch-based model RETRIEVAL Convolutional NEURAL Networks(CNNs) best VIEW cross-domain
Dynamic changes of behaviors,dentate gyrus neurogenesis and hippocampal miR-124 expression in rats with depression induced by chronic unpredictable mild stress 预览
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作者 Yun-Ling Huang Ning-Xi Zeng +5 位作者 Jie Chen Jie Niu Wu-Long Luo Ping Liu Can Yan Li-Li Wu 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第6期1150-1159,共10页
The depression-like behavior phenotype,neurogenesis in the dentate gyrus and miR-124 expression in the hippocampus are the focus of current research on the pathogenesis of depression and antidepressant therapy.The pre... The depression-like behavior phenotype,neurogenesis in the dentate gyrus and miR-124 expression in the hippocampus are the focus of current research on the pathogenesis of depression and antidepressant therapy.The present study aimed to clarify the dynamic changes of depression-like behavior,dentate gyrus neurogenesis and hippocampal miR-124 expression during depression induced by chronic stress to reveal pathological features at different stages of depression and to further provide insight into depression treatment.Chronic unpredictable mild stress depression models were established by exposing Sprague-Dawley rats to various mild stressors,including white noise,thermal swimming,stroboscopic illumination,soiled cages,pairing with three other stressed animals,cold swimming,tail pinch,restraint and water and food deprivation.Chronic unpredictable mild stress model rats underwent dynamic observation from 1 to 8 weeks and were compared with a control group(normal feeding without any stressors).To observe changes in the depression-like behavior phenotype during chronic unpredictable mild stress-induced depression,a sucrose preference test was used to evaluate the degree of anhedonia.An open-field test was used to evaluate locomotor activity and anxiety status.Compared with the control group,chronic unpredictable mild stress rats lost weight but did not have a depression-like behavioral phenotype at 1-4 weeks.Chronic unpredictable mild stress rats presented decreased sucrose preference and locomotor activity at 5-8 weeks.In addition,chronic unpredictable mild stress rats did not have significant anxiety-like behavior during 1-8 weeks of modeling.To observe neurogenesis dysfunctions and changes in neuronal number in the dentate gyrus during chronic unpredictable mild stress-induced depression,markers(DCX and DCX/BrdU)of neural proliferation and differentiation and the neuronal marker NeuN were assessed by immunofluorescence.Compared with the control group,neurogenesis and the neuronal number in the dentate gyrus did not 展开更多
关键词 chronic unpredictable mild stress model continuous observation DEPRESSION depression-like behavior dynamic changes HIPPOCAMPUS miR-124 neurogenesis dysfunction neuronal loss
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Animal models used to study direct peripheral nerve repair:a systematic review 预览
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作者 Francisco Javier Vela Guadalupe Martínez-Chacón +3 位作者 Alberto Ballestín JoséLuis Campos Francisco Miguel Sánchez-Margallo Elena Abellán 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第3期491-502,共12页
Objective:Peripheral nerve repair is required after traumatic injury.This common condition represents a major public health problem worldwide.Recovery after nerve repair depends on several factors,including the severi... Objective:Peripheral nerve repair is required after traumatic injury.This common condition represents a major public health problem worldwide.Recovery after nerve repair depends on several factors,including the severity of the injury,the nerve involved,and the surgeon’s technical skills.Despite the precise microsurgical repair of nerve lesions,adequate functional recovery is not always achieved and,therefore,the regeneration process and surgical techniques are still being studied.Pre-clinical animal models are essential for this research and,for this reason,the focus of the present systematic review(according to the PRISMA statement)was to analyze the different animal models used in pre-clinical peripheral nerve repair studies.Data sources:Original articles,published in English from 2000 to 2018,were collected using the Web of Science,Scopus,and PubMed databases.Data selection:Only preclinical trials on direct nerve repair were included in this review.The articles were evaluated by the first two authors,in accordance with predefined data fields.Outcome measures:The primary outcomes included functional motor abilities,daily activity and regeneration rate.Secondary outcomes included coaptation technique and animal model.Results:This review yielded 267 articles,of which,after completion of the screening,49 studies were analyzed.There were 1425 animals in those 49 studies,being rats,mice,guinea pigs,rabbits,cats and dogs the different pre-clinical models.The nerves used were classified into three groups:head and neck(11),forelimb(8)and hindlimb(30).The techniques used to perform the coaptation were:microsuture(46),glue(12),laser(8)and mechanical(2).The follow-up examinations were histology(43),electrophysiological analysis(24)and behavioral observation(22).Conclusion:The most widely used animal model in the study of peripheral nerve repair is the rat.Other animal models are also used but the cost-benefit of the rat model provides several strengths over the others.Suture techniques are currently the first option for 展开更多
关键词 NERVE MICROSURGERY peripheral NERVE regeneration REPAIR reconstruction DIRECT NERVE REPAIR animal model coaptation PRISMA systematic review
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Stem cell therapy for Parkinson’s disease:safety and modeling 预览
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作者 Theo Stoddard-Bennett Renee Reijo Pera 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第1期36-40,共5页
For decades,clinicians have developed medications and therapies to alleviate the symptoms of Parkinson’s disease,but no treatment currently can slow or even stop the progression of this localized neurodegeneration.Fo... For decades,clinicians have developed medications and therapies to alleviate the symptoms of Parkinson’s disease,but no treatment currently can slow or even stop the progression of this localized neurodegeneration.Fortunately,sparked by the genetic revolution,stem cell reprogramming research and the advancing capabilities of personalization in medicine enable forward-thinking to unprecedented patient-specific modeling and cell therapies for Parkinson’s disease using induced pluripotent stem cells(iPSCs).In addition to modeling Parkinson’s disease more accurately than chemically-induced animal models,patient-specific stem cell lines can be created,elucidating the effects of genetic susceptibility and sub-populations’differing responses to in vitro treatments.Sourcing cell therapy with iPSC lines provides ethical advantages because these stem cell lines do not require the sacrifice of human zygotes and genetically-specific drug trails can be tested in vitro without lasting damage to patients.In hopes of finally slowing the progression of Parkinson’s disease or re-establishing function,iPSC lines can ultimately be corrected with gene therapy and used as cell sources for neural transplantation for Parkinson’s disease.With relatively localized neural degeneration,similar to spinal column injury,Parkinson’s disease presents a better candidacy for cell therapy when compared to other diffuse degeneration found in Alzheimer’s or Huntington’s Disease.Neurosurgical implantation of pluripotent cells poses the risk of an innate immune response and tumorigenesis.Precautions,therefore,must be taken to ensure cell line quality before transplantation.While cell quality can be quantified using a number of assays,a yielding a high percentage of therapeutically relevant dopaminergic neurons,minimal de novo genetic mutations,and standard chromosomal structure is of the utmost importance.Current techniques focus on iPSCs because they can be matched with donors using human leukocyte antigens,thereby reducing the sever 展开更多
关键词 alpha SYNUCLEIN animal model cell therapy DOPAMINERGIC neurons induced PLURIPOTENT STEM CELLS NEURODEGENERATION Parksinson’s disease STEM CELLS
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miR-155干预烧伤急性肺损伤模型大鼠:核转录因子κB通路的变化 预览
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作者 黎鸿章 杨坤 +3 位作者 刘玉文 刘攀 邱波 邹杰 《中国组织工程研究》 CAS 北大核心 2020年第2期204-208,共5页
背景:目前有研究关注核转录因子κB通路在烧伤大鼠急性肺损伤病理过程中的作用及机制,如miR-155靶向抑制KB激酶,进而减弱核转录因子κB活性,在烧伤大鼠急性肺损伤发挥作用,然而仍存在病理机制有待研究和确认。目的:观察miR-155通过核转... 背景:目前有研究关注核转录因子κB通路在烧伤大鼠急性肺损伤病理过程中的作用及机制,如miR-155靶向抑制KB激酶,进而减弱核转录因子κB活性,在烧伤大鼠急性肺损伤发挥作用,然而仍存在病理机制有待研究和确认。目的:观察miR-155通过核转录因子κB通路对烧伤大鼠急性肺损伤的影响。方法:采用温水水浴模拟烫伤法建立烧伤急性肺损伤大鼠模型,将烧伤大鼠随机分为烧伤急性肺损伤组、miR-155增强试剂组和miR-155抑制试剂组,液体复苏后,miR-155增强试剂组、miR-155抑制试剂组大鼠分别尾静脉注入5μL的miR-155-mimics和miR-155-inhibitions。酶联免疫吸附剂测定肺泡灌洗液中肿瘤坏死因子α、白细胞介素1β的变化情况;苏木精-伊红染色法观察3组肺组织形态变化;Western blot法检测核转录因子κB及环氧化酶2蛋白表达;免疫组织化学染色检测肺组织核转录因子κB蛋白表达。结果与结论:①苏木精-伊红染色结果表明,miR-155抑制试剂组、烧伤急性肺损伤组及miR-155增强试剂组肺组织损伤程度,逐渐加重(P<0.05);②酶联免疫吸附实验结果表明,与烧伤急性肺损伤组相比,miR-155增强试剂组肿瘤坏死因子α、白细胞介素1β表达增加(P<0.05),而miR-155抑制试剂组肿瘤坏死因子α、白细胞介素1β表达降低(P<0.05);③Western结果表明,与烧伤急性肺损伤组相比,miR-155增强试剂组核转录因子κB、环氧化酶2蛋白表达增加(P<0.05),而miR-155抑制试剂组核转录因子κB、环氧化酶2蛋白表达降低(P<0.05);④免疫组织化学染色结果显示,miR-155抑制试剂组核转录因子κB蛋白表达增强,呈深棕色,中性粒细胞、单核巨噬细胞、肺泡上皮细胞的胞质及胞核内核转录因子κB表达最明显;⑤上述数据证实,肺组织细胞中核转录因子κB活性降低,可以通过下调miR-155来实现,从而降低肺损伤组织间的炎症反应。实验于2018年6月经内江市第一人 展开更多
关键词 MIR-155 大鼠 急性肺损伤 模型 核转录因子ΚB 环氧化酶2 炎症 白细胞介素1Β 肿瘤坏死因子α 苏木精-伊红染色
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Heterogeneity in the regenerative abilities of central nervous system axons within species:why do some neurons regenerate better than others? 预览
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作者 William Rodemer Jianli Hu +1 位作者 Michael E.Selzer Michael I.Shifman 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第6期996-1005,共10页
Some neurons,especially in mammalian peripheral nervous system or in lower vertebrate or in vertebrate central nervous system(CNS)regenerate after axotomy,while most mammalian CNS neurons fail to regenerate.There is a... Some neurons,especially in mammalian peripheral nervous system or in lower vertebrate or in vertebrate central nervous system(CNS)regenerate after axotomy,while most mammalian CNS neurons fail to regenerate.There is an emerging consensus that neurons have different intrinsic regenerative capabilities,which theoretically could be manipulated therapeutically to improve regeneration.Population-based comparisons between"good regenerating"and"bad regenerating"neurons in the CNS and peripheral nervous system of most vertebrates yield results that are inconclusive or difficult to interpret.At least in part,this reflects the great diversity of cells in the mammalian CNS.Using mammalian nervous system imposes several methodical limitations.First,the small sizes and large numbers of neurons in the CNS make it very difficult to distinguish regenerating neurons from non-regenerating ones.Second,the lack of identifiable neurons makes it impossible to correlate biochemical changes in a neuron with axonal damage of the same neuron,and therefore,to dissect the molecular mechanisms of regeneration on the level of single neurons.This review will survey the reported responses to axon injury and the determinants of axon regeneration,emphasizing non-mammalian model organisms,which are often under-utilized,but in which the data are especially easy to interpret. 展开更多
关键词 axonal regeneration identifiable neurons intrinsic factors LAMPREY Mauthner cell Müller cell neuronal death non-mammalian model organisms spinal cord injury zebrafish
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Jidong cognitive impairment cohort study:objectives,design,and baseline screening 预览
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作者 Dai-Yu Song Xian-Wei Wang +9 位作者 Sa Wang Si-Qi Ge Guo-Yong Ding Xue-Yu Chen Yan-Ru Chen Hua-Min Liu Xiao-Mei Xie Wei-Jia Xing Dong Li Yong Zhou 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第6期1111-1119,共9页
The risk of dementia increases in patients with cognitive impairment.However,it is not clear what factors contribute to the onset of dementia in those with cognitive impairment.In this prospective cohort study,we will... The risk of dementia increases in patients with cognitive impairment.However,it is not clear what factors contribute to the onset of dementia in those with cognitive impairment.In this prospective cohort study,we will investigate the every-five-year incidence of cognitive impairment and prognostic factors for cognitive impairment.The Jidong cognitive impairment cohort was established from April 2012 to August 2015,during which we recruited 5854 healthy participants(55.1%male)older than 45 years(mean,57 years).Participants received a health examination in the Staff Hospital,Jidong Oilfield Branch,China National Petroleum Corporation.Baseline data and blood samples were collected.Cognitive impairment was evaluated using the Mini-Mental State Examination,and was defined as a Mini-Mental State Examination score of less than 24.Dementia was assessed using the criteria of Diagnostic and Statistical Manual of Mental Disorders(Fourth edition),the International Working Group criteria,and the Mini-Mental State Examination score.The follow-up will continue until December 2024,during which a prognostic model will be constructed.The primary outcome is the presence/absence of dementia and the secondary outcome is quality of life.Baseline screening results showed the following:(1)Cognitive impairment was apparent in 320 participants(5.5%).These participants will be excluded from the Jidong cohort study,and the remaining participants will be followed up.(2)Of the 320 participants with cognitive impairment,there was a significantly higher prevalence of illiteracy than other education levels(35.9%,P<0.05).Age,arterial hypertension,alcohol consumption,and passive smoking differed significantly between the cognitive impairment and healthy groups(P<0.05).Multivariate logistic regression models showed that age(odds ratio[OR]=1.059,95%confidence interval[CI]:1.044-1.074)and arterial hypertension(OR=1.665,95%CI:1.143-2.427)were risk factors for mild cognitive impairment.With the increase of educational level(illiteracy,primary school,ju 展开更多
关键词 assessment cognitive impairment COMMUNITY DEMENTIA FOLLOW-UP Mini-Mental Status Examination Scale model new basis prevention prognostic factors
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Coupling of a Regional Climate Model with a Crop Development Model and Evaluation of the Coupled Model across China 预览
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作者 Jing ZOU Zhenghui XIE +4 位作者 Chesheng ZHAN Feng CHEN Peihua QIN Tong HU Jinbo XIE 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第5期527-540,共14页
In this study,the CERES(Crop Estimation through Resource and Environment Synthesis)crop model was coupled with CLM3.5,the land module of the regional climate model RegCM4.The new coupled model was named RegCM4 CERES;a... In this study,the CERES(Crop Estimation through Resource and Environment Synthesis)crop model was coupled with CLM3.5,the land module of the regional climate model RegCM4.The new coupled model was named RegCM4 CERES;and in this model,crop type was further divided into winter wheat,spring wheat,spring maize,summer maize,early rice,late rice,single rice,and other crop types based on each distribution fraction.The development of each crop sub-type was simulated by the corresponding crop model separately,with each planting and harvesting date.A simulation test using RegCM4 CERES was conducted across China from 1999 to 2008;a control test was also performed using the original RegCM4.Data on crop LAI(leaf area index),soil moisture at 10 cm depth,precipitation,and 2 m air temperature were collected to evaluate the performance of RegCM4 CERES.The evaluation provided comparison of single-station time series,regional distributions,seasonal variations,and statistical indices for RegCM4 CERES.The results revealed that the coupled model had an excellent ability to simulate the phonological changes and spatial variations in crops.The consideration of dynamic crop development in RegCM4 CERES corrected the wet bias of the original RegCM4 over North China and the cold bias over South China.However,the degree of improvement was minimal and the statistical indices for RegCM4 CERES were roughly the same as the original RegCM4. 展开更多
关键词 MODEL EVALUATION MODEL COUPLING CROP development MODEL regional CLIMATE MODEL CLIMATE modeling
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The pig as a preclinical traumatic brain injury model: current models,functional outcome measures,and translational detection strategies 预览
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作者 Holly A.Kinder Emily W.Baker Franklin D.West 《中国神经再生研究:英文版》 SCIE CAS CSCD 2019年第3期413-424,共12页
Traumatic brain injury(TBI) is a major contributor of long-term disability and a leading cause of death worldwide. A series of secondary injury cascades can contribute to cell death, tissue loss, and ultimately to the... Traumatic brain injury(TBI) is a major contributor of long-term disability and a leading cause of death worldwide. A series of secondary injury cascades can contribute to cell death, tissue loss, and ultimately to the development of functional impairments. However, there are currently no effective therapeutic interventions that improve brain outcomes following TBI. As a result, a number of experimental TBI models have been developed to recapitulate TBI injury mechanisms and to test the efficacy of potential therapeutics. The pig model has recently come to the forefront as the pig brain is closer in size, structure, and composition to the human brain compared to traditional rodent models, making it an ideal large animal model to study TBI pathophysiology and functional outcomes. This review will focus on the shared characteristics between humans and pigs that make them ideal for modeling TBI and will review the three most common pig TBI models–the diffuse axonal injury, the controlled cortical impact, and the fluid percussion models. It will also review current advances in functional outcome assessment measures and other non-invasive, translational TBI detection and measurement tools like biomarker analysis and magnetic resonance imaging. The use of pigs as TBI models and the continued development and improvement of translational assessment modalities have made significant contributions to unraveling the complex cascade of TBI sequela and provide an important means to study potential clinically relevant therapeutic interventions. 展开更多
关键词 traumatic brain INJURY large animal MODEL PIG MODEL diffuse AXONAL INJURY FUNCTIONAL outcome assessment measures controlled cortical impact MODEL fluid percussion INJURY MODEL magnetic resonance imaging biomarkers
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Three Evolutions of the Landscape Cognitive Model from the Perspective of Philosophy 预览
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作者 ZHAO Meihong 《景观研究:英文版》 2019年第3期78-81,共4页
Looking back at the history of landscape design, there are various styles and schools as well as numerous design concepts. From the perspective of philosophical epistemology, landscape design has experienced three per... Looking back at the history of landscape design, there are various styles and schools as well as numerous design concepts. From the perspective of philosophical epistemology, landscape design has experienced three periods, namely, apriorism, empiricism and transcendentalism. Combining the design phenomena in the history of garden design, this paper sorted out the evolution of landscape design in terms of methodology, epistemology and instrumentalism, in order to speculate on the macroscopic trajectory of the evolution of landscape cognitive model. 展开更多
关键词 A priori MODEL EMPIRICISM MODEL TRANSCENDENTALISM MODEL
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Hybrid Model of Time Series Prediction Model for Railway Passenger Flow 预览
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作者 Wei Sha Shuai Qiu +1 位作者 Wenjun Yuan Zhangrong Qin 《国际计算机前沿大会会议论文集》 2019年第2期525-527,共3页
Railway passenger flow forecasting is an important basis for scientific dispatching of railway transportation. In order to remedy the shortcomings of one single time series prediction method for passenger flow, a mode... Railway passenger flow forecasting is an important basis for scientific dispatching of railway transportation. In order to remedy the shortcomings of one single time series prediction method for passenger flow, a model of combining autoregressive integrated moving average (ARIMA) with extreme learning machine (ELM) based on wavelet transform, named WAADE is presented in this paper. Firstly, the complex railway passenger flow time series was decomposed into linear and non-linear components by wavelet transform. Then, the decomposed linear and non-linear components were predicted by using ARIMA and ELM respectively. Finally, the final prediction results were obtained through fusing the linear and nonlinear prediction results by wavelet transform once again. At the same time, considering the obvious seasonal and periodic regularity of the railway passenger flow data, a WAADES model was constructed combined the WAADE model with the seasonal model based on the entropy value method. The experimental results show that the prediction accuracy of proposed WAADE and WAADES model is higher than the one of the ARIMA or ELM or seasonal model when used alone. Because of the combination of seasonal characteristics, the prediction accuracy of WAADES model is higher than that of WAADE model. The effectiveness and superiority of the two combined models proposed are proved. 展开更多
关键词 ARIMA MODEL ELM MODEL WAVELET transform Entropy value method SEASONAL MODEL
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A dual timescale model for micro-mixing and its application in LES-TPDF simulations of turbulent nonpremixed flames
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作者 Fang WANG Rui LIU +2 位作者 Li DOU Denghuan LIU Jie JIN 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第4期875-887,共13页
The numerical simulation of modern aero-engine combustion chamber needs accurate description of the interaction between turbulence and chemical reaction mechanism. The Large Eddy Simulation(LES) method with the Transp... The numerical simulation of modern aero-engine combustion chamber needs accurate description of the interaction between turbulence and chemical reaction mechanism. The Large Eddy Simulation(LES) method with the Transported Probability Density Function(TPDF) turbulence combustion model is promising in engineering applications. In flame region, the impact of chemical reaction should be considered in TPDF molecular mixing model. Based on pioneer research, three new TPDF turbulence-chemistry dual time scale molecular mixing models were proposed tentatively by adding the chemistry time scale in molecular mixing model for nonpremixed flame. The Aero-Engine Combustor Simulation Code(AECSC) which is based on LES-TPDF method was combined with the three new models. Then the Sandia laboratory’s methane-air jet flames: Flame D and Flame E were simulated. Transient simulation results show that all the three new models can predict the instantaneous combustion flow pattern of the jet flames. Furthermore,the average scalar statistical results were compared with the experimental data. The simulation result of the new TPDF arithmetic mean modification model is the closest to the experimental data:the average error in Flame D is 7.6% and 6.6% in Flame E. The extinction and re-ignition phenomena of the jet flames especially Flame E were captured. The turbulence time scale and the chemistry time scale are in different order in the whole flow field. The dual time scale TPDF combustion model has ability to deal with both the turbulence effect and the chemistry reaction effect, as well as their interaction more accurately for nonpremixed flames. 展开更多
关键词 DUAL TIME scale MODEL Large EDDY simulation Sandia methane-air jet ?ame TPDF molecular mixing MODEL Turbulence combustion MODEL
我国动力煤期货市场的价格发现效率测度
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作者 邹绍辉 马婷艳 田倍诚 《煤炭经济研究》 2019年第2期12-19,共8页
选取我国供给侧改革前后的两年期动力煤期货和现货价格日数据,以VECM模型为基础,创新性地使用信息份额IS模型,最新修正信息份额MIS模型以及永久短暂PT模型,对我国动力煤期现货市场受到短期内和长期内的新信息冲击时的价格发现效率进行... 选取我国供给侧改革前后的两年期动力煤期货和现货价格日数据,以VECM模型为基础,创新性地使用信息份额IS模型,最新修正信息份额MIS模型以及永久短暂PT模型,对我国动力煤期现货市场受到短期内和长期内的新信息冲击时的价格发现效率进行实证研究并比较。结果表明:当我国动力煤期货市场受到短期内的新信息冲击时,供给侧改革后的期货价格发现效率更高,对现货市场的引导作用较强,效果更显著、持久;当我国动力煤期货市场受到长期内的新信息冲击时,供给侧改革前的期货价格发现效率更高,与现货市场为单向因果关系;整体而言,我国动力煤期货市场的价格发现效率高于现货市场,处于核心地位。 展开更多
关键词 动力煤期货 价格发现 IS模型 MIS模型 PT模型
An experimental method for quantitative analysis of real contact area based on the total reflection optical principle
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作者 罗治军 宋保江 +1 位作者 韩靖宇 阎绍泽 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第5期158-165,共8页
The simulation of real contact area between materials is foundationally important for the contact mechanics of mechanical structures.The Greenwood and Williamson (GW) model and the Majumdar (MB) model are the basic mo... The simulation of real contact area between materials is foundationally important for the contact mechanics of mechanical structures.The Greenwood and Williamson (GW) model and the Majumdar (MB) model are the basic models in this field,which are widely accepted and proven to be valid in many experiments and engineering.Although the contact models have evolved considerably in recent years,the verifications of the models are most based on the indirect methods such as electrical conductivity and contact stiffness,because of the lack of effective methods to directly measure the variation of contact surface.In this paper,the total reflection (TR) method is introduced into the verification of contact models.An experiment system based on TR method is constructed to measure the real contact area of two PMMA specimens.The comparison analysis between the results of experiment and models suggests that the experiment result has the same trend with simulation,the MB model has better agreement with the experimental result because this method can take into account the variation of radius and the merging of asperities,while the GW model has a huge deviation because of the dependence on resolution and the lack of considering the variation of radius and asperity’s merging process.Taking the interaction of asperities into account could give a better result that is closer to the experiment.Our results and analysis prove that the experimental methods in this paper could be used as a more direct and valid method to quantitatively measure the real contact area and to verify the contact models. 展开更多
关键词 real contact area Greenwood and WILLIAMSON (GW) MODEL Majumdar (MB) MODEL Persson’s MODEL total REFLECTION (TR) method
GIS-based landslide susceptibility mapping using numerical risk factor bivariate model and its ensemble with linear multivariate regression and boosted regression tree algorithms
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作者 Alireza ARABAMERI Biswajeet PRADHAN +2 位作者 Khalil REZAE Masoud SOHRABI Zahra KALANTARI 《山地科学学报:英文版》 SCIE CSCD 2019年第3期595-618,共24页
In this study, a novel approach of the landslide numerical risk factor(LNRF) bivariate model was used in ensemble with linear multivariate regression(LMR) and boosted regression tree(BRT) models, coupled with radar re... In this study, a novel approach of the landslide numerical risk factor(LNRF) bivariate model was used in ensemble with linear multivariate regression(LMR) and boosted regression tree(BRT) models, coupled with radar remote sensing data and geographic information system(GIS), for landslide susceptibility mapping(LSM) in the Gorganroud watershed, Iran. Fifteen topographic, hydrological, geological and environmental conditioning factors and a landslide inventory(70%, or 298 landslides) were used in mapping. Phased array-type L-band synthetic aperture radar data were used to extract topographic parameters. Coefficients of tolerance and variance inflation factor were used to determine the coherence among conditioning factors. Data for the landslide inventory map were obtained from various resources, such as Iranian Landslide Working Party(ILWP), Forestry, Rangeland and Watershed Organisation(FRWO), extensive field surveys, interpretation of aerial photos and satellite images, and radar data. Of the total data, 30% were used to validate LSMs, using area under the curve(AUC), frequency ratio(FR) and seed cell area index(SCAI).Normalised difference vegetation index, land use/land cover and slope degree in BRT model elevation, rainfall and distance from stream were found to be important factors and were given the highest weightage in modelling. Validation results using AUC showed that the ensemble LNRF-BRT and LNRFLMR models(AUC = 0.912(91.2%) and 0.907(90.7%), respectively) had high predictive accuracy than the LNRF model alone(AUC = 0.855(85.5%)). The FR and SCAI analyses showed that all models divided the parameter classes with high precision. Overall, our novel approach of combining multivariate and machine learning methods with bivariate models, radar remote sensing data and GIS proved to be a powerful tool for landslide susceptibility mapping. 展开更多
关键词 LANDSLIDE susceptibility GIS Remote sensing BIVARIATE MODEL MULTIVARIATE MODEL Machine learning MODEL
An Improved Enthalpy-Based Lattice Boltzmann 3D Model with Added Probability Function for the Growth Characteristics of Frost Layer
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作者 CUI Jing YANG Tinghao +1 位作者 YANG Fan YANG Guangfeng 《热科学学报:英文版》 SCIE EI CAS CSCD 2019年第2期378-392,共15页
In this paper, the effects of different surface properties on the growth of frost layer were numerically studied from the mesoscopic scale using the lattice Boltzmann method. The improved enthalpy method and nucleatio... In this paper, the effects of different surface properties on the growth of frost layer were numerically studied from the mesoscopic scale using the lattice Boltzmann method. The improved enthalpy method and nucleation probability model were combined to establish a three-dimensional lattice Boltzmann model based on nucleation probability theory. The model was used to carry out numerical research on frost layer formation and growth process on cold wall surface. The model could not only simulate the gradual densification and thickening process of frost layer growth from the macro scale, but also describe the change process of the frost layer structure caused by ice branch growth on the micro scale. The average thickness, average density and the amount of the frost layer could be obtained. Through this model, the temporal and spatial evolution characteristics of the topography of the frost layer were obtained. The model was used to analyze the effects of cold wall surface temperature, relative humidity and cold surface wettability on the frosting characteristics. The average thickness, frost average density, frost quality and average solid volume fraction of frost at different times were obtained by calculation. 展开更多
关键词 lattice Boltzmann MODEL IMPROVED ENTHALPY MODEL nucleation probability MODEL three-dimensional FROST surface WETTABILITY
Modeling aggregate size distribution of eroded sediment resulting from rain-splash and raindrop impacted flow processe 预览
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作者 Selen Deviren Saygin Gunay Erpul 《国际泥沙研究:英文版》 SCIE 2019年第2期166-177,共12页
Soil susceptibility to detachment and transport sub-processes of erosion is generally controled by the aggregate breakdown mechanism. Measuring particle size and aggregation to the estimate erodibility potential of so... Soil susceptibility to detachment and transport sub-processes of erosion is generally controled by the aggregate breakdown mechanism. Measuring particle size and aggregation to the estimate erodibility potential of soils is important under erosive rainfall conditions. The Aggregate Size Distribution (ASD) is one of the most important determinants of soil structure along with soil organic matter content for describing the efficiency of applied, sustainable management strategies. This study aimed to compare the performances of three different aggregate size distribution models to predict the characteristic aggregate size parameter (median diameter, D50) for eroded sediment from interrill erosion processes of Rain- Splash Transport (RST) and Raindrop Impacted Flow Transport (RIFT). The ASDs of 1143 collected sediment samples from the RST and RIFT processes were measured and modeled by the Log-normal, Fractal, and Weibull approaches. The D50 value, as a characteristic parameter for aggregate size distributions, derived from the cumulative ASD curve was compared for soils from different land use types and different slope and rainfall intensity conditions. The performance of each model was evaluated using the Mean Square Error (MSE) and Coefficient of Determination (R^2). The Weibull approach was the most accurate model showing the best fit with the lowest MSE values (0.0002 ≤MSE≤ 0.0048) and having the greatest R2 values (0.936≤ R^2≤ 0.998) when compared with the Log-normal and Fractal models. Herewith, for semi-arid land use and soil, specific shape and scale parameters for the Weibull distribution, the respective ASDs were successfully re-generated for modeling the eroded sediment of the simulated RST and RIFT interill processes. 展开更多
关键词 AGGREGATE SIZE distribution Eroded SEDIMENT Log-normal MODEL FRACTAL MODEL Weibull MODEL
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Is China’s Economy Overestimated?*——Counter-Evidence from the Underground Economy 预览
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作者 王永兴 《中国经济学人:英文版》 2019年第3期30-43,共14页
Over the past four decades of reform and opening up since 1978, China’s GDP has been growing at 9.5% on an annual average basis. While some scholars believe that China’s economic growth is systematically overestimat... Over the past four decades of reform and opening up since 1978, China’s GDP has been growing at 9.5% on an annual average basis. While some scholars believe that China’s economic growth is systematically overestimated, this paper carries out an estimation of China’s underground economy and finds that due to the existence of the underground economy, China’s real GDP is systematically underestimated. China’s official GDP statistics generally reflect a real picture of its economic growth. The size of China’s underground economy is significantly influenced by total electricity consumption, the selfemployed ratio, labor participation rate and money supply. These findings are of great significance for policy-making. 展开更多
关键词 underground economy LATENT variable CASH ratio MODEL MULTIPLE indicators MULTIPLE causes (MIMIC) MODEL
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