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Spatial and temporal analysis of beta diversity in the Barro Colorado Island forest dynamics plot, Panama 预览
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作者 Pierre Legendre Richard Condit 《森林生态系统:英文版》 CSCD 2019年第1期76-86,共11页
Background: Ecologists are interested in assessing the spatial and temporal variation in ecological surveys repeated over time. This paper compares the 1985 and 2015 surveys of the Barro Colorado Forest Dynamics plot(... Background: Ecologists are interested in assessing the spatial and temporal variation in ecological surveys repeated over time. This paper compares the 1985 and 2015 surveys of the Barro Colorado Forest Dynamics plot(BCI), Panama,divided into 1250(20 m × 20 m) quadrats.Methods, spatial analysis: Total beta diversity was measured as the total variance of the Hellinger-transformed community data throughout the BCI plot. Total beta was partitioned into contributions of individual sites(LCBD indices), which were tested for significance and mapped.Results, spatial analysis: LCBD indices indicated the sites with exceptional community composition. In 1985,they were mostly found in the swamp habitat. In the 2015 survey, none of the swamp quadrats had significant LCBDs.What happened to the tree community in the interval?Methods, temporal analysis: The dissimilarity in community composition in each quadrat was measured between time 1(1985) and time 2(2015). Temporal Beta Indices(TBI) were computed from abundance and presence-absence data and tested for significance. TBI indices can be decomposed into B = species(or abundances-per-species) losses and C = species(or abundances-per-species) gains. B-C plots were produced;they display visually the relative importance of the loss and gain components, through time, across the sites.Results, temporal analysis: In BCI, quadrats with significant TBI indices were found in the swamp area, which is shrinking in importance due to changes to the local climate. A published habitat classification divided the BCI forest plot into six habitat zones. Graphs of the B and C components were produced for each habitat group. Group 4(the swamp) was dominated by species(and abundances-per-species) gains whereas the five other habitat groups were dominated by losses, some groups more than others.Conclusions: We identified the species that had changed the most in abundances in the swamp between T1 and T2.This analysis supported the hypothesis that the swamp is drying out and is invaded by species fr 展开更多
关键词 BETA DIVERSITY B-C PLOTS BCI forest dynamics PLOT SPACE-TIME analysis Temporal BETA DIVERSITY
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Physiological effects of amyloid precursor protein and its derivatives on neural stem cell biology and signaling pathways involved 预览
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作者 Raquel Coronel Charlotte Palmer +4 位作者 Adela Bernabeu-Zornoza María Monteagudo Andreea Rosca Alberto Zambrano Isabel Liste 《中国神经再生研究:英文版》 SCIE CAS CSCD 2019年第10期1661-1671,共11页
The pathological implication of amyloid precursor protein(APP)in Alzheimer’s disease has been widely documented due to its involvement in the generation of amyloid-β peptide.However,the physiological functions of AP... The pathological implication of amyloid precursor protein(APP)in Alzheimer’s disease has been widely documented due to its involvement in the generation of amyloid-β peptide.However,the physiological functions of APP are still poorly understood.APP is considered a multimodal protein due to its role in a wide variety of processes,both in the embryo and in the adult brain.Specifically,APP seems to play a key role in the proliferation,differentiation and maturation of neural stem cells.In addition,APP can be processed through two canonical processing pathways,generating different functionally active fragments:soluble APP-α,soluble APP-β,amyloid-β peptide and the APP intracellular C-terminal domain.These fragments also appear to modulate various functions in neural stem cells,including the processes of proliferation,neurogenesis,gliogenesis or cell death.However,the molecular mechanisms involved in these effects are still unclear.In this review,we summarize the physiological functions of APP and its main proteolytic derivatives in neural stem cells,as well as the possible signaling pathways that could be implicated in these effects.The knowledge of these functions and signaling pathways involved in the onset or during the development of Alzheimer’s disease is essential to advance the understanding of the pathogenesis of Alzheimer’s disease,and in the search for potential therapeutic targets. 展开更多
关键词 AMYLOID precursor protein APP SOLUBLE APP alpha SOLUBLE APP BETA AMYLOID BETA peptide APP intracellular domain NEURAL stem CELLS NEURAL progenitor CELLS neurogenesis signaling pathways
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An ethanolic extract of Bailian (Radix Ampelopsis Japonicae): demonstration of colorectal cancer treatment efficacy via inhibition of β-catenin signaling in vitro
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作者 Su Tao Wang Xinning +5 位作者 Li Chunyu Bai Jingxuan Chi-Yan Cheng Fu Xiuqiong Li Ting Yu Zhiling 《中医杂志:英文版》 SCIE CAS CSCD 2019年第3期339-345,共7页
OBJECTIVE:To investigate the underlying mechanism of Bailian (Radix Ampelopsis Japonicae,BL) extract action on colorectal cancer (CRC).METHODS:We explored the involvement of β-catenin signaling on the anti-CRC effect... OBJECTIVE:To investigate the underlying mechanism of Bailian (Radix Ampelopsis Japonicae,BL) extract action on colorectal cancer (CRC).METHODS:We explored the involvement of β-catenin signaling on the anti-CRC effects of an BL ethanolic extract (BLE) in cell models by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay,immunofluorescent staining,luciferase assay,Western blot analysis and real-time quantitative polymerase chain reaction analysis.Anti-CRC compounds were quantified by high performance liquid chromatography.RESULTS:The contents of gallic acid,catechin,and epicatechin in the BLE were 0.23,1.25,and 0.18 g/kg,respectively.BLE-mediated cytotoxic and apoptotic effects were accompanied by lowered β-catenin/Tcf transcriptional activity,reduced β-catenin nuclear localization,and downregulated protein and mRNA levels of both β-catenin and molecules regulated by β-catenin.CONCLUSION:The mechanism underpinning the anti-CRC effects of BLE may involve inhibition of β-catenin signaling.Further studies are necessary to establish the role of β-catenin signaling in the action of BLE-mediated anti-CRC effects. 展开更多
关键词 Bailian (Radix Ampelopsis Japonicae) Colorectal NEOPLASMS Beta CATENIN CYTOTOXINS Apoptosis
Effect of Salinity and Potassium Enrichment on Some Growth Attributes in Sugar Beet (Beta vulgaris L.) 预览
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作者 Fadi Abbas Entessar Al-Jbawi 《农业科学与技术:B》 2019年第3期152-159,共8页
A pot experiment was conducted during winter growing season of 2014 at Homs Agriculture Research Center, General Commission for Scientific Researches (GCSAR), Syria. A factorial experiment arranged according to comple... A pot experiment was conducted during winter growing season of 2014 at Homs Agriculture Research Center, General Commission for Scientific Researches (GCSAR), Syria. A factorial experiment arranged according to complete randomized block design with six replications was used. A combination of four levels of saline irrigation water (tap water, 2,000, 4,000 and 6,000 ppm), with three K levels (180, 360 and 540 ppm), was used to evaluate the effects of saline irrigation water and K enrichment on some growth attributes of two sugar beet varieties (Semper and Alligator). Results showed that all studied growth attributes, i.e., leaf area (LA), leaf number (LN), total dry matter (TDM) and net assimilation rate (NAR) were decreased under salinity stress conditions compared to the control, while K enrichment significantly increased some of the studied characters such as LA, TDM and NAR, but the differences in LN were apparent according to increase in K levels. The variety Semper surpassed significantly the variety Alligator in LA, TDM and NAR. Results also indicated a significant interaction between salinity×potassium enrichment, varieties×potassium enrichment and salinity ? varieties. 展开更多
关键词 SALINITY POTASSIUM ENRICHMENT GROWTH traits sugar BEET (Beta VULGARIS L.)
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寒地“贝达”葡萄汁化学降酸最佳方案研究 预览
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作者 刘云清 李艳青 朱磊 《高师理科学刊》 2019年第8期54-57,70共5页
以寒地产"贝达"葡萄为原料,采用单盐法和复盐法对葡萄汁进行化学降酸,通过理化性质的测定和感官品质的评价,确定了化学降酸的最佳方案.结果表明,与单盐法相比,复盐法在每种降酸剂添加量相对较低的情况下获得了更理想的降酸效... 以寒地产"贝达"葡萄为原料,采用单盐法和复盐法对葡萄汁进行化学降酸,通过理化性质的测定和感官品质的评价,确定了化学降酸的最佳方案.结果表明,与单盐法相比,复盐法在每种降酸剂添加量相对较低的情况下获得了更理想的降酸效果,添加0.6g/LCaCO3和1.5g/LK2CO3组合的葡萄汁,总酸含量和pH值分别为13.35g/L和2.98,降酸幅度为2.80g/L,且感官品质的综合评分最高.化学降酸的最佳方案确定为0.6g/LCaCO3和1.5g/LK2CO3组合的复盐法,此方案适用于寒地"贝达"葡萄汁和葡萄酒的化学降酸. 展开更多
关键词 寒地 贝达 葡萄汁 化学降酸 最佳方案
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Proteomics of the mediodorsal thalamic nucleus of rats with stress-induced gastric ulcer 预览
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作者 Sheng-Nan Gong Jian-Ping Zhu +1 位作者 Ying-Jie Ma Dong-Qin Zhao 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第23期2911-2923,共13页
BACKGROUND Stress-induced gastric ulcer(SGU) is one of the most common visceral complications after trauma. Restraint water-immersion stress(RWIS) can cause serious gastrointestinal dysfunction and has been widely use... BACKGROUND Stress-induced gastric ulcer(SGU) is one of the most common visceral complications after trauma. Restraint water-immersion stress(RWIS) can cause serious gastrointestinal dysfunction and has been widely used to study the pathogenesis of SGU to identify medications that can cure the disease. The mediodorsal thalamic nucleus(MD) is the centre integrating visceral and physical activity and contributes to SGU induced by RWIS. Hence, the role of the MD during RWIS needs to be studied.AIM To screen for differentially expressed proteins in the MD of the RWIS rats to further elucidate molecular mechanisms of SGU.METHODS Male Wistar rats were selected randomly and divided into two groups, namely, a control group and an RWIS group. Gastric mucosal lesions of the sacrificed rats were measured using the erosion index and the proteomic profiles of the MD were generated through isobaric tags for relative and absolute quantitation(iTRAQ) coupled with two-dimensional liquid chromatography and tandem mass spectrometry. Additionally, iTRAQ results were verified by Western blot analysis.RESULTS A total of 2853 proteins were identified, and these included 65 dysregulated(31 upregulated and 34 downregulated) proteins(fold change ratio ≥ 1.2). Gene Ontology(GO) analysis showed that most of the upregulated proteins are primarily related to cell division, whereas most of the downregulated proteins are related to neuron morphogenesis and neurotransmitter regulation. Ingenuity Pathway Analysis revealed that the dysregulated proteins are mainly involved in the neurological disease signalling pathways. Furthermore, our results indicated that glycogen synthase kinase-3 beta might be related to the central mechanismthrough which RWIS gives rise to SGU.CONCLUSION Quantitative proteomic analysis elucidated the molecular targets associated with the production of SGU and provides insights into the role of the MD. The underlying molecular mechanisms need to be further dissected. 展开更多
关键词 Mediodorsal THALAMIC nucleus Proteome Restraint water-immersion STRESS Stress-induced gastric ulcer GLYCOGEN SYNTHASE kinase-3 beta
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Modeling hot deformation behavior of low-cost Ti-2Al-9.2Mo-2Fe beta titanium alloy using a deep neural network
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作者 Cheng-Lin Li P.L.Narayana +4 位作者 N.S.Reddy Seong-Woo Choi Jong-Taek Yeom Jae-Keun Hong Chan Hee Park 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第5期907-916,共10页
Ti-2 Al-9.2 Mo-2 Fe is a low-cost β titanium alloy with well-balanced strength and ductility, but hot working of this alloy is complex and unfamiliar. Understanding the nonlinear relationships among the strain,strain... Ti-2 Al-9.2 Mo-2 Fe is a low-cost β titanium alloy with well-balanced strength and ductility, but hot working of this alloy is complex and unfamiliar. Understanding the nonlinear relationships among the strain,strain rate, temperature, and flow stress of this alloy is essential to optimize the hot working process.In this study, a deep neural network(DNN) model was developed to correlate flow stress with a wide range of strains(0.025–0.6), strain rates(0.01–10 s^-1) and temperatures(750–1000℃). The model, which was tested with 96 unseen datasets, showed better performance than existing models, with a correlation coefficient of 0.999. The processing map constructed using the DNN model was effective in predicting the microstructural evolution of the alloy. Moreover, it led to the optimization of hot-working conditions to avoid the formation of brittle precipitates(temperatures of 820–1000℃ and strain rates of 0.01-0.1 s^-1). 展开更多
关键词 DEEP neural networks Back propagation Processing map RECRYSTALLIZATION BETA titanium
Interaction between climate and management on beta diversity components of vegetation in relation to soil properties in arid and semi-arid oak forests, Iran
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作者 Heydari MEHDI Aazami FATEMEH +4 位作者 Faramarzi MARZBAN Omidipour REZA Bazgir MASOUD Pothier DAVID Prévosto BERNARD 《干旱区科学:英文版》 SCIE CSCD 2019年第1期43-57,共15页
This study aimed to investigate the interaction between regions with different climatic conditions(arid vs. semi-arid) and management(protected vs. unprotected) on the turnover and nestedness of vegetation in relation... This study aimed to investigate the interaction between regions with different climatic conditions(arid vs. semi-arid) and management(protected vs. unprotected) on the turnover and nestedness of vegetation in relation to physical, chemical and biological properties of soils in the Ilam Province of Iran. In each of the two regions, we sampled 8 sites(4 managed and 4 unmanaged sites) within each of which we established 4 circular plots(1000 m~2) that were used to investigate woody species, while two micro-plots(1 m×1 m) were established in each 1000-m~2 plot to analyze herbaceous species. In each sample unit, we also extracted three soil samples(0–20 cm depth) for measuring soil properties. The results indicated that the interaction between region and conservational management significantly affected the percent of canopy cover of Persian oak(Quercus brantii Linddl), soil respiration, substrate-induced respiration, as well as beta and gamma diversities and turnover of plant species. The percent of oak canopy cover was positively correlated with soil silt, electrical conductivity, available potassium, and alpha diversity, whereas it was negatively correlated with plant turnover. In addition, plant turnover was positively related to available phosphorus, while nestedness of species was positively related to organic carbon and total nitrogen. According to these results, we concluded that physical, chemical, and biological characteristics of limited ecological niche generally influenced plant diversity. Also, this study demonstrated the major contribution of the beta diversity on gamma diversity, especially in semi-arid region, because of the higher heterogeneity of vegetation in this area. 展开更多
关键词 climatic conditions conservation MANAGEMENT beta diversity OAK FORESTS physical-chemical property SEMI-ARID region
Polycomb chromobox Cbx2 enhances antiviral innate immunity by promoting Jmjd3-mediated demethylation of H3K27 at the Ifnb promoter
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作者 Donghao Sun Xuetao Cao Chunmei Wang 《蛋白质与细胞:英文版》 SCIE CAS CSCD 2019年第4期285-294,共10页
Polycomb chromobox(CBX)proteins regulate gene transcription by maintaining chromatin states,which guide a variety of biological processes.Now,epigenetic regulation of innate immune response is an emerging field.Howeve... Polycomb chromobox(CBX)proteins regulate gene transcription by maintaining chromatin states,which guide a variety of biological processes.Now,epigenetic regulation of innate immune response is an emerging field.However,the role of CBX proteins in innate immunity remains unclear.We confirmed that the expression of CBX family proteins,especially Cbx2,was decreased in macrophages upon viral infection,and then we investigated the role of Cbx2 in the antiviral immune response.Silencing or knockdown of Cbx2 in macrophages inhibited virus-induced production of IFNp.Furthermore,heterozygous Cbx2 knockout were susceptible to VSV challenge.Mechanistically,Cbx2 binds to and recruits Jmjd3 to the Ifnb promoter,leading to demethylation of H3K27me3 and increased transcription of IFN-β.Together,our study reveals a nontraditional function of a Cbx protein and adds new insight into the epigenetic regulation of antiviral innate immunity. 展开更多
关键词 Cbx2 Jmjd3 INTERFERON beta INNATE immunity
Mooring System Optimisation and Effect of Different Line Design Variables on Motions of Truss Spar Platforms in Intact and Damaged Conditions 预览
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作者 O.A. Montasir A. Yenduri V.J. Kurian 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第4期385-397,共13页
This paper presents the effect of mooring diameters, fairlead slopes and pretensions on the dynamic responses of a truss spar platform in intact and damaged line conditions. The platform is modelled as a rigid body wi... This paper presents the effect of mooring diameters, fairlead slopes and pretensions on the dynamic responses of a truss spar platform in intact and damaged line conditions. The platform is modelled as a rigid body with three degrees-of-freedom and its motions are analysed in time-domain using the implicit Newmark Beta technique. The mooring restoring force-excursion relationship is evaluated using quasi-static approach. MATLAB codes DATSpar and QSAML, are developed to compute the dynamic responses of truss spar platform and to determine the mooring system stiffness. To eliminate the conventional trial and error approach in the mooring system design, a numerical tool is also developed and described in this paper for optimising the mooring configuration. It has a graphical user interface and includes regrouping particle swarm optimisation technique combined with DATSpar and QSAML. A case study of truss spar platform with ten mooring lines is analysed using this numerical tool. The results show that optimum mooring system design benefits the oil and gas industry to economise the project cost in terms of material, weight, structural load onto the platform as well as manpower requirements. This tool is useful especially for the preliminary design of truss spar platforms and its mooring system. 展开更多
关键词 MOORING optimisation spar platform particle swarm Morison equation implicit NEWMARK beta QUASI-STATIC
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‘贝达’葡萄根系腐解物对土壤酚类物质和速效养分的影响 预览
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作者 李坤 周婷 +3 位作者 郭修武 李成祥 郭印山 刘镇东 《中外葡萄与葡萄酒》 2019年第2期14-19,共6页
为了探究不同质地土壤条件下葡萄连作效应差异机制,本试验以‘贝达’(V.riparia×V.labrusca)葡萄为试材,选取砂质土(大连)和壤质土(熊岳)为研究对象(未种植过葡萄),外源添加‘贝达’葡萄根系腐解物模拟连作条件,分析了酚类物质和... 为了探究不同质地土壤条件下葡萄连作效应差异机制,本试验以‘贝达’(V.riparia×V.labrusca)葡萄为试材,选取砂质土(大连)和壤质土(熊岳)为研究对象(未种植过葡萄),外源添加‘贝达’葡萄根系腐解物模拟连作条件,分析了酚类物质和土壤速效养分在不同质地土壤条件下的变化情况。结果表明:添加‘贝达’根系腐解物后,砂质土中的水溶性酚酸含量呈下降趋势,而壤质土中水溶性酚酸含量呈升高趋势;在砂质土壤中,添加根系腐解物后能够降低根际土壤中碱解氮含量,增加速效钾含量;在壤质土中,能够增加根际土壤中碱解氮含量,适度增加速效钾含量。推测葡萄植株在含有根系腐解物的壤质土中没有表现出化感抑制效应,可能与其增加了土壤碱解氮含量相关。 展开更多
关键词 贝达 根系腐解物 酚类物质 土壤速效养分
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Exploratory study of betavoltaic battery using ZnO as the energy converting material 预览
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作者 Xiao-Yi Li Jing-Bin Lu +3 位作者 Yu-Min Liu Xu Xu Rui He Ren-Zhou Zheng 《核技术:英文版》 SCIE CAS CSCD 2019年第4期62-69,共8页
Third-generation-semiconductor zinc oxide is utilized as an energy converting material in a betavoltaic battery, where 0.06 Ci63 Ni and 8 Ci147 Pm are used as the beta sources. Based on a Monte Carlo simulation, the f... Third-generation-semiconductor zinc oxide is utilized as an energy converting material in a betavoltaic battery, where 0.06 Ci63 Ni and 8 Ci147 Pm are used as the beta sources. Based on a Monte Carlo simulation, the full scales of the devices are derived as 17 and 118 lm,respectively, for both sources. The influences of semiconductor doping concentrations on the electrical properties of the devices are analyzed. For a typical doping concentration NA= 1017 cm-3, ND= 1016 cm-3, the conversion efficiencies are 7.177% and 1.658%, respectively, using63 Ni and147 Pm sources. The calculation results of energy deposition in materials for the two sources show that the doping concentrations drop to 1 × 1013–5×1014 cm-3 and 1 × 1012–5×1013, and accordingly, the energy conversion efficiencies rise to 14.212% and 18.359%, respectively. 展开更多
关键词 RADIOISOTOPE BETA voltaic effect Zinc OXIDE Nuclear BATTERY Monte Carlo simulation
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Additive manufacturing of Ti-6Al-4V lattice structures with high structural integrity under large compressive deformation
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作者 Kun Yang Jian Wang +3 位作者 Liang Jia Guangyu Yang Huiping Tang Yuanyuan Li 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第2期303-308,共6页
Additively manufactured Ti-6Al-4V lattice structures have found important niche applications. However, they often show insufficient compressive ductility or in sufficient structural integrity. I n this study, a batch ... Additively manufactured Ti-6Al-4V lattice structures have found important niche applications. However, they often show insufficient compressive ductility or in sufficient structural integrity. I n this study, a batch of 45 octahedral Ti-6Al-4V lattice structures was manufactured in three different strut diameters (0.5, 1.0, 1.5 mm) by selective electron beam melting (SEBM). The influence of post-SEBM annealing on the compressive deformation characteristics of the lattice structure was investigated. The as-built Ti- 6AI-4V lattices fragmented when the compressive strain reached 13%-23% depending on strut diameter. Annealing at 950℃(P transus temperature: 995℃) only slightly improved the compressive ductility of the lattice structures. However, annealing at 1050℃(p-annealing) fundamentally changed the compressive deformation mode of the lattice structures. The resultant compressive stress-strain curve was featured by a long smooth plateau and no facture occurred even after significant densification of the lattice structure had taken place (>50% of compressive strain). 展开更多
关键词 Selective electron beam MELTING TI-6AL-4V LATTICE structures DUCTILITY ANNEALING BETA ANNEALING
Bioinformatic identification of key candidate genes and pathways in axon regeneration after spinal cord injury in zebrafish 预览
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作者 Jia-He Li Zhong-Ju Shi +6 位作者 Yan Li Bin Pan Shi-Yang Yuan Lin-Lin Shi Yan Hao Fu-Jiang Cao Shi-Qing Feng 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第1期103-111,共9页
Zebrafish and human genomes are highly homologous;however,despite this genomic similarity,adult zebrafish can achieve neuronal proliferation,regeneration and functional restoration within 6–8 weeks after spinal cord ... Zebrafish and human genomes are highly homologous;however,despite this genomic similarity,adult zebrafish can achieve neuronal proliferation,regeneration and functional restoration within 6–8 weeks after spinal cord injury,whereas humans cannot.To analyze differentially expressed zebrafish genes between axon-regenerated neurons and axon-non-regenerated neurons after spinal cord injury,and to explore the key genes and pathways of axonal regeneration after spinal cord injury,microarray GSE56842 was analyzed using the online tool,GEO2R,in the Gene Expression Omnibus database.Gene ontology and protein-protein interaction networks were used to analyze the identified differentially expressed genes.Finally,we screened for genes and pathways that may play a role in spinal cord injury repair in zebrafish and mammals.A total of 636 differentially expressed genes were obtained,including 255 up-regulated and 381 down-regulated differentially expressed genes in axon-regenerated neurons.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment results were also obtained.A protein-protein interaction network contained 480 node genes and 1976 node connections.We also obtained the 10 hub genes with the highest correlation and the two modules with the highest score.The results showed that spectrin may promote axonal regeneration after spinal cord injury in zebrafish.Transforming growth factor beta signaling may inhibit repair after spinal cord injury in zebrafish.Focal adhesion or tight junctions may play an important role in the migration and proliferation of some cells,such as Schwann cells or neural progenitor cells,after spinal cord injury in zebrafish.Bioinformatic analysis identified key candidate genes and pathways in axonal regeneration after spinal cord injury in zebrafish,providing targets for treatment of spinal cord injury in mammals. 展开更多
关键词 axonal regeneration differentially expressed genes focal adhesions Gene Ontology Kyoto Encyclopedia of Genes and Genomes neural regeneration protein-protein interaction network signaling pathway SPECTRIN tight junctions transforming growth factor beta Wnt signaling pathway
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Catalytic performance of Cu- and Zr-modified beta zeolite catalysts in the methylation of 2-methylnaphthalene
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作者 Fatih Gulec Farooq Sher Ali Karaduman 《石油科学:英文版》 SCIE CAS CSCD 2019年第1期161-172,共12页
2,6Dim-ethylnaphthalene (2,6-DMN) is a commercially important chemical for the production of polyethylenenaphthalate and polybutylene naphthalate. However, its complex synthesis procedure and high production cost sign... 2,6Dim-ethylnaphthalene (2,6-DMN) is a commercially important chemical for the production of polyethylenenaphthalate and polybutylene naphthalate. However, its complex synthesis procedure and high production cost significantly reduce the use of 2,6-DMN. In this study, the synthesis of 2,6-DMN was investigated with methylation of 2-methylnaphthalene (2- MN) over metal-loaded beta zeolite catalysts including beta zeolite, Cu-impregnated beta zeolite and Zr-impregnated beta zeolite. The experiments were performed in a fixed-bed reactor at atmospheric pressure under a nitrogen atmosphere. The reactor was operated at a temperature range of 400-500 °C and varying weight hourly space velocity between 1 and 3 h_1. The results demonstrated that 2,6-DMN can be synthesized by methylation of 2-MN over beta type zeolite catalysts. Besides 2,6-DMN, the product stream also contained other DMN isomers such as 2,7-DMN, 1,3-DMN, 1,2-DMN and 2,3- DMN. The activity and selectivity of beta zeolite catalyst were remarkably enhanced by Zr impregnation, whereas Cu modification of beta zeolite catalyst had an insignificant effect on its selectivity. The highest conversion of 2-MN reached 81%, the highest ratio of 2,6-DMN/2,7-DMN reached 2.6 and the highest selectivity of 2,6-DMN was found to be 20% by using Zr-modified beta zeolite catalyst. 展开更多
关键词 METHYLATION NAPHTHALENE derivatives Polyethylenenaphthalate 2 6-DIMETHYLNAPHTHALENE and BETA ZEOLITE catalyst
Protective mechanism of testosterone on cognitive impairment in a rat model of Alzheimer’s disease 预览
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作者 Xu-Sheng Yan Zhan-Jun Yang +5 位作者 Jian-Xin Jia Wei Song Xin Fang Zhi-Ping Cai Dong-Sheng Huo He Wang 《中国神经再生研究:英文版》 SCIE CAS CSCD 2019年第4期649-657,共9页
Cognitive dysfunction in Alzheimer’s disease is strongly associated with a reduction in synaptic plasticity, which may be induced by oxidative stress. Testosterone is beneficial in learning and memory, although the u... Cognitive dysfunction in Alzheimer’s disease is strongly associated with a reduction in synaptic plasticity, which may be induced by oxidative stress. Testosterone is beneficial in learning and memory, although the underlying protective mechanism of testosterone on cognitive performance remains unclear. This study explored the protective mechanism of a subcutaneous injection of 0.75 mg testosterone on cognitive dysfunction induced by bilateral injections of amyloid beta 1–42 oligomers into the lateral ventricles of male rats. Morris water maze test results demonstrated that testosterone treatment remarkably reduced escape latency and path length in Alzheimer’s disease rat models. During probe trials, testosterone administration significantly elevated the percentage of time spent in the target quadrant and the number of platform crossings. However, flutamide, an androgen receptor antagonist, inhibited the protective effect of testosterone on cognitive performance in Alzheimer’s disease rat models. Nissl staining, immunohistochemistry, western blot assay, and enzyme-linked immunosorbent assay results showed that the number of intact hippocampal pyramidal cells, the dendritic spine density in the hippocampal CA1 region, the immune response and expression level of postsynaptic density protein 95 in the hippocampus, and the activities of superoxide dismutase and glutathione peroxidase were increased with testosterone treatment. In contrast, testosterone treatment reduced malondialdehyde levels. Flutamide inhibited the effects of testosterone on all of these indicators. Our data showed that the protective effect of testosterone on cognitive dysfunction in Alzheimer’s disease is mediated via androgen receptors to scavenge free radicals, thereby enhancing synaptic plasticity. 展开更多
关键词 nerve REGENERATION Alzheimer’s disease TESTOSTERONE cognitive dysfunction synaptic plasticity free radicals Morris water maze androgen receptor FLUTAMIDE POSTSYNAPTIC density protein 95 amyloid beta 1–42 NEURODEGENERATIVE change neural REGENERATION
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超短效肾上腺素β受体阻滞药:兰地洛尔
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作者 黄震华 《中国新药与临床杂志》 CAS CSCD 北大核心 2019年第4期193-197,共5页
兰地洛尔是一个新型的超短效肾上腺素β受体阻滞药,具有选择性高、起效快、停药后失效快、对心脏血流动力学影响小等优点。兰地洛尔可减少围手术期窦性心动过速和室上性心动过速发生率,减少术后心房颤动发生率,有助于术后心房颤动患者复... 兰地洛尔是一个新型的超短效肾上腺素β受体阻滞药,具有选择性高、起效快、停药后失效快、对心脏血流动力学影响小等优点。兰地洛尔可减少围手术期窦性心动过速和室上性心动过速发生率,减少术后心房颤动发生率,有助于术后心房颤动患者复律,减轻经皮冠状动脉介入治疗时节律和血流动力学异常。 展开更多
关键词 兰地洛尔 受体 肾上腺素β 抗心律失常药 心动过速 室上性 心房颤动
西北干旱区软儿梨与甜菜的间作栽植模式
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作者 关淑琳 张正鹏 《林业科技通讯》 2018年第9期68-69,共2页
为实现软儿梨种植模式的多元化,有效增加农民在软儿梨栽培期间的短期收益,笔者在西北干旱区采用软儿梨间作甜菜(Beta vulgaris L.)的栽植模式,使软儿梨的成活率达到了80%,并且取得了良好的经济效益。
关键词 软儿梨 甜菜 BETA VULGARIS L. 间作 栽植模式
PKCβ抑制剂Ruboxistaurin对糖尿病大鼠不同脏器抗氧化物质的影响 预览
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作者 罗军 夏中元 +2 位作者 张元 苏娃婷 雷少青 《山西医科大学学报》 CAS 2018年第9期1026-1030,共5页
目的探究PKCβ抑制剂Ruboxistaurin(RBX)对糖尿病大鼠不同脏器抗氧化物质的影响。方法采用随机数字表法将30只8周龄雄性SD大鼠(220-250 g)分为三组:正常对照组(Con组,n=6)、糖尿病组(DM组,n=11)和糖尿病+RBX治疗组(DM+RBX组... 目的探究PKCβ抑制剂Ruboxistaurin(RBX)对糖尿病大鼠不同脏器抗氧化物质的影响。方法采用随机数字表法将30只8周龄雄性SD大鼠(220-250 g)分为三组:正常对照组(Con组,n=6)、糖尿病组(DM组,n=11)和糖尿病+RBX治疗组(DM+RBX组,n=12)。糖尿病模型成功4周时,相应商品化试剂盒检测各组大鼠心、肺、肝、肾组织总抗氧化物含量,超氧化物歧化酶(superoxide dismutase,SOD)及过氧化氢酶(catlase,CAT)活性。结果与Con组相比,DM组大鼠饮水量,进食量,排尿量,血糖水平,血甘油三酯水平,心组织总抗氧化物含量,心组织SOD活性及心、肝、肾组织CAT活性显著增加(P〈0.05);而体质量,肺、肝、肾组织总抗氧化物含量及SOD活性显著降低(P〈0.05)。与DM组相比,DM+RBX组大鼠进食量、排尿量、血糖水平、血甘油三酯水平、心组织SOD及CAT活性显著降低(P〈0.05);而心、肾组织总抗氧化物含量及肾组织SOD活性显著增加(P〈0.05)。结论 RBX治疗可有效缓解糖尿病大鼠症状,其机制可能与改善多脏器抗氧化功能相关。 展开更多
关键词 蛋白激酶C BETA 糖尿病 氧化应激 RUBOXISTAURIN
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Changes of tropical cyclone tracks in the western North Pacific over19792016 预览
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作者 ZHANG Wen-Qian WU Li-Guang ZOU Xu-Kai 《气候变化研究进展:英文版》 CSCD 2018年第3期170-176,共7页
The tropical cyclone (TC) trajectory model has been widely used to investigate the mechanism of the climate change of TC tracks. In thisstudy, the Gaussian weight interpolation method is used to calculate the beta d... The tropical cyclone (TC) trajectory model has been widely used to investigate the mechanism of the climate change of TC tracks. In thisstudy, the Gaussian weight interpolation method is used to calculate the beta drift in the TC track or trajectory model. By simulating historicalTC tracks, the new calculation can better simulate the spatial distribution of the frequency of TC occurrence. The improved track model isfurther used to understand the TC track change during the period of 1979e2016. In 1979e2016, the TC activity has been suppressed in theSouth China Sea (SCS) while the TC influence along the southeast coastal regions of China has been increased. The sensitivity experimentsindicate that the change of the formation location plays a dominant role in decreasing TC influence in the SCS while the change of theenvironmental steering flows increases the TC influence in the eastern coastal region of China. This study suggests that the ongoing climatechange can affect the TC activity along the coast of China. 展开更多
关键词 TROPICAL CYCLONE TRAJECTORY model Beta DRIFT Formation position Large-scale STEERING FLOWS
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