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L形冷弯薄壁型钢组合钢管混凝土柱轴压性能
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作者 吴丽丽 刘艳霞 +1 位作者 武海鹏 韩港豪 《哈尔滨工业大学学报》 EI CAS 北大核心 2025年第1期77-91,共15页
为解决异形钢管混凝土柱阴角对其承载力的影响,提出了用1个冷弯薄壁方钢管和2个U形钢管焊接成L形钢管,内填充混凝土形成L形冷弯薄壁型钢组合钢管混凝土柱形式。设计了5组共10根试件的轴压试验,并开展了有限元参数分析,研究了钢管厚度、... 为解决异形钢管混凝土柱阴角对其承载力的影响,提出了用1个冷弯薄壁方钢管和2个U形钢管焊接成L形钢管,内填充混凝土形成L形冷弯薄壁型钢组合钢管混凝土柱形式。设计了5组共10根试件的轴压试验,并开展了有限元参数分析,研究了钢管厚度、U形管外伸长度和钢材强度等参数对构件承载力和延性等力学性能的影响。结果表明:该类试件的主要破坏形态为中上部局部鼓曲破坏,适量增大U形管外伸长度可以提高承载力,但增大到一定程度之后易发生弯扭破坏;承载力和延性随着钢管厚度和钢材强度增大而增加;混凝土强度对构件的初始刚度和峰值荷载的影响都很小,但对曲线下降段的影响较大;试件端部和中部截面阴角处的混凝土应力值比各边中部更大,说明采用U形钢管与方钢管组合的方式改善了阴角处钢管对混凝土约束普遍较弱的问题。基于“统一理论”,给出了两种承载力建议计算公式,与试验结果吻合较好,两种计算方法在0.44~1.94的约束效应系数范围内具有良好的适用性。 展开更多
关键词 l U形管 钢管混凝土柱 轴心受压 承载力
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甘蓝型油菜BnaSLY1基因进化分析及功能研究
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作者 李嘉欣 黄莹莹 +7 位作者 吴潞梅 赵伦 易斌 马朝芝 涂金星 沈金雄 傅廷栋 文静 《作物学报》 CAS 北大核心 2025年第1期44-57,共14页
赤霉素调控植物表皮细胞增长、茎叶伸长以及株型建成。拟南芥SLY1属于F-box蛋白,它通过靶向泛素化赤霉素信号转导路径的负向调控因子——DELLA蛋白来影响植物生长发育,然而油菜中BnaSLY1的基因功能尚未揭示。本研究对BnaSLY1进行了表达... 赤霉素调控植物表皮细胞增长、茎叶伸长以及株型建成。拟南芥SLY1属于F-box蛋白,它通过靶向泛素化赤霉素信号转导路径的负向调控因子——DELLA蛋白来影响植物生长发育,然而油菜中BnaSLY1的基因功能尚未揭示。本研究对BnaSLY1进行了表达特征和进化树分析,利用CRISPR/Cas9技术创制了BnaSLY1不同拷贝数的突变体,结合RNA-Seq技术对BnaSLY1的生物学功能及其对油菜生长发育的影响进行了研究。结果表明,甘蓝型油菜Westar中有2个SLY1同源拷贝BnaA01.SLY1和BnaA06.SLY1,它们表达模式基本相同,为组成型表达基因,其蛋白定位在细胞核,且在不同的油菜品种及十字花科植物间序列保守。与对照相比,单突bnaa01sly1和bnaa06sly1开花时间推迟,株高显著降低,而双突bnasly1还表现出深绿色光叶表型,叶片厚度增加,开花期比单突进一步推迟,株高也进一步降低。RNA-Seq结果显示,双突与Westar之间的差异表达基因显著富集在生长素信号转导路径以及蜡质合成通路,多个开花时间相关基因表达也发生显著变化。本研究表明, BnaSLY1除影响植物株高和开花时间等生长发育进程,还影响表皮蜡质合成,为探索赤霉素信号转导路径在甘蓝型油菜生长发育中的重要作用奠定了理论基础。 展开更多
关键词 甘蓝型油菜 BnaSlY1 赤霉素 株型 蜡质合成 开花时间 RNA-SEQ
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缺血性脑卒中铁死亡特征基因NFE2L2的鉴定与验证
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作者 王咪 马书杰 +1 位作者 刘杨 齐瑞 《中国组织工程研究》 CAS 北大核心 2025年第7期1466-1474,共9页
背景:铁死亡与缺血性脑卒中的发病密切相关,靶向铁死亡是一种治疗缺血性脑卒中有前景的方案,但具体调控靶点尚不明确。目的:通过生物信息学和机器学习方法筛选缺血性脑卒中铁死亡相关特征基因,并通过细胞实验进行验证,探讨铁死亡在缺血... 背景:铁死亡与缺血性脑卒中的发病密切相关,靶向铁死亡是一种治疗缺血性脑卒中有前景的方案,但具体调控靶点尚不明确。目的:通过生物信息学和机器学习方法筛选缺血性脑卒中铁死亡相关特征基因,并通过细胞实验进行验证,探讨铁死亡在缺血性脑卒中的作用。方法:基于GEO数据库和FerrDb数据库选取符合条件的缺血性脑卒中相关数据集和铁死亡表达数据集,通过t检验筛选铁死亡相关差异基因。对铁死亡相关差异基因进行GO功能富集分析与KEGG信号通路富集分析。通过PPI网络分析和机器学习筛选缺血性脑卒中铁死亡的特征基因,利用ROC分析和GSEA分析探究特征基因的准确性和生物功能。然后进行细胞实验,将HT22细胞分为对照组与缺血性脑卒中组,对照组不作任何干预,缺血性脑卒中组加入0.1 mol/L的H_(2)O_(2)干预24 h诱导细胞氧化应激和铁死亡,通过实时荧光定量RT-PCR和Western Blot验证铁死亡的发生和特征基因表达。结果与结论:(1)共获取45个铁死亡相关差异基因,GO和KEGG富集分析发现差异基因与氧化应激、自噬、铁死亡、脂肪细胞因子信号通路和线粒体代谢密切相关。(2)通过PPI网络中的MCODE插件和cytoHubba插件与机器学习中的LASSO算法和SVM-RFE算法共鉴定出1个铁死亡特征基因核因子E2相关因子2(nuclear factor erythroid 2-related factor 2,NFE2L2)。(3)对NFE2L2进行ROC曲线分析,发现在训练集和验证集中构建的诊断预测模型具有良好的准确性与特异性;对NFE2L2进行GSEA分析,发现特征基因通过免疫、炎症反应、氨基酸代谢及神经因子调控等方面参与缺血性脑卒中发病机制的调控。(4)细胞实验的RT-PCR和Western Blot分析表明,与对照组对比,缺血性脑卒中组中的酰基辅酶A合成酶长链家族成员4 mRNA和蛋白表达水平显著增高(P<0.05),谷胱甘肽过氧化物酶4 mRNA和蛋白表达水平显著降低(P<0.05);与对照组对比,缺血性脑卒中组中特征基因NFE2L2 mRNA和蛋白表达水平显著增高(P<0.05)。(5)上述结果证实,缺血性脑卒中与铁死亡密切相关,靶向特征基因NFE2L2可以为研究和治疗缺血性脑卒中提供一定的思路与方向。 展开更多
关键词 缺血性脑卒中 铁死亡 生物信息学 HT22细胞 机器学习 特征基因 细胞实验 NFE2l2 ASCl4 GPX4
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Effects of P301L-TAU on post-translational modifications of microtubules in human iPSC-derived cortical neurons and TAU transgenic mice
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作者 Mohamed Aghyad Al Kabbani Christoph Köhler Hans Zempel 《Neural Regeneration Research》 SCIE CAS 2025年第8期2348-2360,共13页
TAU is a microtubule-associated protein that promotes microtubule assembly and stability in the axon.TAU is missorted and aggregated in an array of diseases known as tauopathies.Microtubules are essential for neuronal... TAU is a microtubule-associated protein that promotes microtubule assembly and stability in the axon.TAU is missorted and aggregated in an array of diseases known as tauopathies.Microtubules are essential for neuronal function and regulated via a complex set of post-translational modifications,changes of which affect microtubule stability and dynamics,microtubule interaction with other proteins and cellular structures,and mediate recruitment of microtubule-severing enzymes.As impairment of microtubule dynamics causes neuronal dysfunction,we hypothesize cognitive impairment in human disease to be impacted by impairment of microtubule dynamics.We therefore aimed to study the effects of a disease-causing mutation of TAU(P301L)on the levels and localization of microtubule post-translational modifications indicative of microtubule stability and dynamics,to assess whether P301L-TAU causes stability-changing modifications to microtubules.To investigate TAU localization,phosphorylation,and effects on tubulin post-translational modifications,we expressed wild-type or P301L-TAU in human MAPT-KO induced pluripotent stem cell-derived neurons(i Neurons)and studied TAU in neurons in the hippocampus of mice transgenic for human P301L-TAU(p R5 mice).Human neurons expressing the longest TAU isoform(2N4R)with the P301L mutation showed increased TAU phosphorylation at the AT8,but not the p-Ser-262 epitope,and increased polyglutamylation and acetylation of microtubules compared with endogenous TAU-expressing neurons.P301L-TAU showed pronounced somatodendritic presence,but also successful axonal enrichment and a similar axodendritic distribution comparable to exogenously expressed 2N4R-wildtype-TAU.P301L-TAU-expressing hippocampal neurons in transgenic mice showed prominent missorting and tauopathy-typical AT8-phosphorylation of TAU and increased polyglutamylation,but reduced acetylation,of microtubules compared with non-transgenic littermates.In sum,P301L-TAU results in changes in microtubule PTMs,suggestive of impairment of microtubule stability.This is accompanied by missorting and aggregation of TAU in mice but not in i Neurons.Microtubule PTMs/impairment may be of key importance in tauopathies. 展开更多
关键词 human induced pluripotent stem cell MICROTUBUlES P301l pR5 mice TAU TAUOPATHY tubulin code
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Loss-of-function mutations of microRNA-142-3p promote ASH1L expression to induce immune evasion and hepatocellular carcinoma progression
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作者 Xing-Hui Yu Yan Xie +8 位作者 Jian Yu Kun-Ning Zhang Zhou-Bo Guo Di Wang Zhao-Xian Li Wei-Qi Zhang Yu-Ying Tan Li Zhang Wen-Tao Jiang 《World Journal of Gastroenterology》 SCIE CAS 2025年第1期126-145,共20页
BACKGROUND Hepatocellular carcinoma(HCC)has been a pervasive malignancy throughout the world with elevated mortality.Efficient therapeutic targets are beneficial to treat and predict the disease.Currently,the exact mo... BACKGROUND Hepatocellular carcinoma(HCC)has been a pervasive malignancy throughout the world with elevated mortality.Efficient therapeutic targets are beneficial to treat and predict the disease.Currently,the exact molecular mechanisms leading to the progression of HCC are still unclear.Research has shown that the microRNA-142-3p level decreases in HCC,whereas bioinformatics analysis of the cancer genome atlas database shows the ASH1L expression increased among liver tumor tissues.In this paper,we will explore the effects and mechanisms of microRNA-142-3p and ASH1L affect the prognosis of HCC patients and HCC cell bioactivity,and the association between them.AIM To investigate the effects and mechanisms of microRNA-142-3p and ASH1L on the HCC cell bioactivity and prognosis of HCC patients.METHODS In this study,we grouped HCC patients according to their immunohistochemistry results of ASH1L with pathological tissues,and retrospectively analyzed the prognosis of HCC patients.Furthermore,explored the roles and mechanisms of microRNA-142-3p and ASH1L by cellular and animal experiments,which involved the following experimental methods:Immunohistochemical staining,western blot,quantitative real-time-polymerase chain reaction,flow cytometric analysis,tumor xenografts in nude mice,etc.The statistical methods involved in this study contained t-test,one-way analysis of variance,theχ^(2)test,the Kaplan-Meier approach and the log-rank test.RESULTS In this study,we found that HCC patients with high expression of ASH1L possess a more recurrence rate as well as a decreased overall survival rate.ASH1L promotes the tumorigenicity of HCC and microRNA-142-3p exhibits reduced expression in HCC tissues and interacts with ASH1L through targeting the ASH1L 3′untranslated region.Furthermore,microRNA-142-3p promotes apoptosis and inhibits proliferation,invasion,and migration of HCC cell lines in vitro via ASH1L.For the exploration mechanism,we found ASH1L may promote an immunosuppressive microenvironment in HCC and ASH1L affects the expression of the cell junction protein zonula occludens-1,which is potentially relevant to the immune system.CONCLUSION Loss function of microRNA-142-3p induces cancer progression and immune evasion through upregulation of ASH1L in HCC.Both microRNA-142-3p and ASH1L can feature as new biomarker for HCC in the future. 展开更多
关键词 Hepatocellular carcinoma MicroRNA-142-3p ASH1l Immune evasion Tumor immune microenvironment Apoptosis
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载富血小板血浆水凝胶对L929细胞氧化损伤的保护作用
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作者 王自林 牟秋菊 +2 位作者 刘宏杰 申玉雪 祝丽丽 《中国组织工程研究》 CAS 北大核心 2025年第4期771-779,共9页
背景:在慢性创面愈合过程中,活性氧的过量生成可能会损害L929成纤维细胞的功能,从而延缓创面修复,因此保护成纤维细胞免受氧化应激的影响对于促进创面愈合非常重要。目的:评估羧甲基壳聚糖-氧化硫酸软骨素/富血小板血浆(CMC-OCS/PRP)水... 背景:在慢性创面愈合过程中,活性氧的过量生成可能会损害L929成纤维细胞的功能,从而延缓创面修复,因此保护成纤维细胞免受氧化应激的影响对于促进创面愈合非常重要。目的:评估羧甲基壳聚糖-氧化硫酸软骨素/富血小板血浆(CMC-OCS/PRP)水凝胶对H2O2刺激下L929细胞的保护作用。方法:制备CMC-OCS/PRP水凝胶,表征水凝胶的微观形貌、降解性能、清除H2O2与羟基自由基的能力及生物相容性。取生长状态良好的L929细胞,分5组培养:对照组常规培养,H2O2组加入H2O2,CMC-OCS组加入羧甲基壳聚糖-氧化硫酸软骨素水凝胶浸提液+H2O2,PRP组加入富血小板血浆凝胶浸提液+H2O2,CMC-OCS/PRP组加入羧甲基壳聚糖-氧化硫酸软骨素/富血小板血浆水凝胶浸提液处理+H2O2,每组先加入水凝胶浸提液处理6 h,然后再加入H2O2处理24 h。培养结束后,检测细胞活性氧及丙二醛水平,细胞凋亡、胶原纤维Ⅰ蛋白表达。在加入H2O2的情况下,将上述水凝胶浸提液分别与L929成纤维细胞直接或间接共培养36 h,通过划痕实验、Transwell小室实验检测细胞的迁移能力。结果与结论:①CMC-OCS/PRP水凝胶具有均匀相互关联的多孔结构及良好的降解能力,体外可有效清除H2O2与羟基自由基,并且具有良好的生物相容性;②与对照组比较,H2O2组细胞凋亡率、细胞活性氧与丙二醛水平升高(P<0.05),细胞铺展面积减少(P<0.05),胶原纤维Ⅰ蛋白表达无明显变化(P>0.05);与H2O2组比较,CMC-OCS组、CMC-OCS/PRP组细胞活性氧水平降低(P<0.05),PRP组、CMC-OCS组、CMCOCS/PRP组丙二醛水平降低(P<0.05)、细胞铺展面积增加(P<0.05),CMC-OCS/PRP组细胞凋亡率降低(P<0.05),PRP组、CMC-OCS组、CMCOCS/PRP组胶原纤维Ⅰ蛋白表达增加(P<0.05);③与对照组比较,H2O2组细胞迁移数量减少(P<0.05),迁移面积无明显变化(P>0.05);与H2O2组比较,PRP组、CMC-OCS组、CMC-OCS/PRP组细胞迁移数量、迁移面积均增加(P<0.05),并且以CMC-OCS/PRP组增加最显著;④在氧化应激条件下,CMC-OCS/PRP水凝胶可改善成纤维细胞的迁移能力,抗细胞凋亡并保护细胞伸展功能。 展开更多
关键词 富血小板血浆 羧甲基壳聚糖 氧化硫酸软骨素 水凝胶 l929细胞 抗氧化
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Recombinant chitinase-3-like protein 1 alleviates learning and memory impairments via M2 microglia polarization in postoperative cognitive dysfunction mice
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作者 Yujia Liu Xue Han +6 位作者 Yan Su Yiming Zhou Minhui Xu Jiyan Xu Zhengliang Ma Xiaoping Gu Tianjiao Xia 《Neural Regeneration Research》 SCIE CAS 2025年第9期2727-2736,共10页
Postoperative cognitive dysfunction is a seve re complication of the central nervous system that occurs after anesthesia and surgery,and has received attention for its high incidence and effect on the quality of life ... Postoperative cognitive dysfunction is a seve re complication of the central nervous system that occurs after anesthesia and surgery,and has received attention for its high incidence and effect on the quality of life of patients.To date,there are no viable treatment options for postoperative cognitive dysfunction.The identification of postoperative cognitive dysfunction hub genes could provide new research directions and therapeutic targets for future research.To identify the signaling mechanisms contributing to postoperative cognitive dysfunction,we first conducted Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of the Gene Expression Omnibus GSE95426 dataset,which consists of mRNAs and long non-coding RNAs differentially expressed in mouse hippocampus3 days after tibial fracture.The dataset was enriched in genes associated with the biological process"regulation of immune cells,"of which Chill was identified as a hub gene.Therefore,we investigated the contribution of chitinase-3-like protein 1 protein expression changes to postoperative cognitive dysfunction in the mouse model of tibial fractu re surgery.Mice were intraperitoneally injected with vehicle or recombinant chitinase-3-like protein 124 hours post-surgery,and the injection groups were compared with untreated control mice for learning and memory capacities using the Y-maze and fear conditioning tests.In addition,protein expression levels of proinflammatory factors(interleukin-1βand inducible nitric oxide synthase),M2-type macrophage markers(CD206 and arginase-1),and cognition-related proteins(brain-derived neurotropic factor and phosphorylated NMDA receptor subunit NR2B)were measured in hippocampus by western blotting.Treatment with recombinant chitinase-3-like protein 1 prevented surgery-induced cognitive impairment,downregulated interleukin-1βand nducible nitric oxide synthase expression,and upregulated CD206,arginase-1,pNR2B,and brain-derived neurotropic factor expression compared with vehicle treatment.Intraperitoneal administration of the specific ERK inhibitor PD98059 diminished the effects of recombinant chitinase-3-like protein 1.Collectively,our findings suggest that recombinant chitinase-3-like protein 1 ameliorates surgery-induced cognitive decline by attenuating neuroinflammation via M2 microglial polarization in the hippocampus.Therefore,recombinant chitinase-3-like protein1 may have therapeutic potential fo r postoperative cognitive dysfunction. 展开更多
关键词 Chil1 hippocampus learning and memory M2 microglia NEUROINFlAMMATION postoperative cognitive dysfunction(POCD) recombinant CHI3l1
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Autism spectrum disorder:difficulties in diagnosis and microRNA biomarkers
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作者 Bridget Martinez Philip V.Peplow 《Neural Regeneration Research》 SCIE CAS 2025年第10期2776-2786,共11页
We performed a PubMed search for microRNAs in autism spectrum disorder that could serve as diagnostic biomarkers in patients and selected 17 articles published from January 2008 to December 2023,of which 4 studies wer... We performed a PubMed search for microRNAs in autism spectrum disorder that could serve as diagnostic biomarkers in patients and selected 17 articles published from January 2008 to December 2023,of which 4 studies were performed with whole blood,4 with blood plasma,5 with blood serum,1 with serum neural cell adhesion molecule L1-captured extracellular vesicles,1 with blood cells,and 2 with peripheral blood mononuclear cells.Most of the studies involved children and the study cohorts were largely males.Many of the studies had performed microRNA sequencing or quantitative polymerase chain reaction assays to measure microRNA expression.Only five studies had used real-time polymerase chain reaction assay to validate microRNA expression in autism spectrum disorder subjects compared to controls.The microRNAs that were validated in these studies may be considered as potential candidate biomarkers for autism spectrum disorder and include miR-500a-5p,-197-5p,-424-5p,-664a-3p,-365a-3p,-619-5p,-664a-3p,-3135a,-328-3p,and-500a-5p in blood plasma and miR-151a-3p,-181b-5p,-320a,-328,-433,-489,-572,-663a,-101-3p,-106b-5p,-19b-3p,-195-5p,and-130a-3p in blood serum of children,and miR-15b-5p and-6126 in whole blood of adults.Several important limitations were identified in the studies reviewed,and need to be taken into account in future studies.Further studies are warranted with children and adults having different levels of autism spectrum disorder severity and consideration should be given to using animal models of autism spectrum disorder to investigate the effects of suppressing or overexpressing specific microRNAs as a novel therapy. 展开更多
关键词 autism spectrum disorder BIOMARKER blood cells blood plasma blood serum DIAGNOSIS MICRORNA peripheral blood mononuclear cells serum neural cell adhesion molecule l1-captured extracellular vesicles whole blood
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Expression analysis of ThGLP, a new germin-like protein gene, in Tamarix hispida 被引量:9
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作者 李慧玉 姜静 +1 位作者 王珊 刘菲菲 《Journal of Forestry Research》 SCIE CAS CSCD 2010年第3期323-330,397,398,共10页
Germin and Germin-like protein (GLP) have various proposed roles in plant developmental stages and stress- related processes. A novel GLP cDNA clone was isolated from a cDNA library of Tamarix hispida. ThGLP, coded ... Germin and Germin-like protein (GLP) have various proposed roles in plant developmental stages and stress- related processes. A novel GLP cDNA clone was isolated from a cDNA library of Tamarix hispida. ThGLP, coded 225aa, possesses conserved motif of plant germin and Germin-like protein. ThGLP belongs to true germin subfamily through phylogenetic analyses. Gene expression profiles in roots and leaves were evaluated using real-time quantitative RT-PCR. The results show that the gene was highly induced by drought, salt, low temperature, CdCl2 and abscisic acid treatments. Our results demonstrate that the ThGLP gene is expressed in leaves and roots, is involved in different abiotic stress re-sponses and controlled by an ABA-dependent signaling pathway. 展开更多
关键词 germin-like protein (GlP) tamarix hispida abiotic stress gene expression
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新疆主要柽柳属植物(Tamarix L.)的生态类型划分与生境相似性研究 被引量:17
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作者 杨维康 张道远 +1 位作者 张立运 尹林克 《干旱区地理》 CSCD 北大核心 2004年第2期186-192,共7页
研究了新疆柽柳属植物的生态类型和生境相似性。根据水、盐两个环境因子 ,将新疆柽柳属植物的生境划分为高水位—低盐组、中高水位—中低盐组、高水位—中盐组、高水位—高盐组、低水位—低盐组和低水位—中盐组六个生境类型组。其下 ,... 研究了新疆柽柳属植物的生态类型和生境相似性。根据水、盐两个环境因子 ,将新疆柽柳属植物的生境划分为高水位—低盐组、中高水位—中低盐组、高水位—中盐组、高水位—高盐组、低水位—低盐组和低水位—中盐组六个生境类型组。其下 ,按照土壤类型又划分成次一级共十个生境类型。此外 ,分析了新疆十种柽柳属植物生境相似性 ,使用聚类分析从土壤类型学角度又将新疆柽柳属植物初步确定出河谷河滩沙砾质新积土型、盐化草甸土型、风沙土型、典型盐土型和泛生境型五个基质生态类群。 展开更多
关键词 柽柳 生态类型 生境相似性 新疆
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Role of Wind-Sand Disturbance in the Formation and Development of Tamarix taklamakanensis Community 被引量:9
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作者 何兴东 高玉葆 任安芝 《Acta Botanica Sinica》 CSCD 2003年第11期1285-1290,共6页
Formation, development and degeneration of Tamarix taklamakanensis M.T. Liu community may be affected by wind-sand disturbance. On the basis of field survey and experiments that took eight years from 1994, it was foun... Formation, development and degeneration of Tamarix taklamakanensis M.T. Liu community may be affected by wind-sand disturbance. On the basis of field survey and experiments that took eight years from 1994, it was found that the plant community was formed in wet and low-lying land, developed in sand burying land, and died out in the land with strong wind erosion and severe sand burying. In the initial stage of the community formation, the low-lying land that was formed by wind erosion provided a suitable habitat for seed germination and plant rooting, but salt stress from ground water reduced seedling survival rate. In the developing stage of the community, sand burying stimulated vigorous growth of the shrubs. In the degenerative stage of the community, the wind erosion and sand burying resulted in dying out of the shrubs. It is therefore concluded that wind-sand disturbance has a positive role in the formation and development of the community, and is in a close association with the process of the community degeneration. Taking the habitat of T taklamakanensis into account, it may be appropriate to note that, under the conditions of frequent disturbance and severe stress, desert pioneer species are adaptable and able to survive. This might be a supplement to the CSR strategy. 展开更多
关键词 Takla Makan tamarix taklamakanensis wind-sand disturbance community formation and development plant strategy
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柽柳(Tamarix spp.)和梭梭(Haloxylon ammodendron)的“肥岛”效应 被引量:54
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作者 李君 赵成义 +1 位作者 朱宏 王锋 《生态学报》 CAS CSCD 北大核心 2007年第12期5138-5147,共10页
灌丛"肥岛"是全球干旱生态系统中的普遍现象,其发生和发展对干旱灌木、草原生态系统的结构和功能都具有重要影响,但其物种效应容易得到忽视。对准噶尔盆地南缘柽柳(Tamarix spp.)和梭梭(Haloxylon ammodendron)这两种不同地... 灌丛"肥岛"是全球干旱生态系统中的普遍现象,其发生和发展对干旱灌木、草原生态系统的结构和功能都具有重要影响,但其物种效应容易得到忽视。对准噶尔盆地南缘柽柳(Tamarix spp.)和梭梭(Haloxylon ammodendron)这两种不同地表形态灌木的冠下、冠缘和灌丛间地3种生境的土壤进行了采样、分析,结果表明:(1)柽柳和梭梭都存在"肥岛"现象,主要表现在土壤表层,其土壤性状与"岛"外土壤的差异随土壤深度增加而减弱;(2)生物性限制土壤养分由"岛"内向外梯度递减,而非生物性限制土壤要素可能高于、也可能低于"岛"外土壤,或者两者无显著差异;(3)从"肥岛"的空间尺度来看,柽柳"肥岛"的水平范围可能超出了本身冠幅覆盖区,而梭梭"肥岛"要小于本身冠幅覆盖区,其深度亦小于柽柳"肥岛";(4)相对于不同土壤要素而言,即使是同一物种,其"肥岛"也具有不同的空间范围。总的来看,研究区灌丛"肥岛"的发育具有明显的物种效应,相对梭梭而言,柽柳"肥岛"发育更广、更深,养分聚集更明显,其原因主要是柽柳的半球型树冠更利于保护和捕获凋落物,而较多的凋落物输入与土壤结构和土壤养分间的正反馈机制使柽柳冠下加速的生物地球化学循环能达到更广、更深的范围。灌丛"肥岛"的发育是干旱景观中生物过程与物理过程交互作用的产物,全面揭示其形成机理,探讨其对干旱生态系统结构、功能与动态的影响,需要更系统的研究。 展开更多
关键词 柽柳 梭梭 肥岛 土壤性状 绿洲-荒漠过渡带
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Research on the extension of Tamarix shrubs resulted from devel-opment projects in arid area 被引量:2
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作者 黄培祐 高瑞如 《Journal of Forestry Research》 SCIE CAS CSCD 2004年第1期45-48,J002,共5页
Tamarix plant is widely distributed in the arid areas of China for its great tolerance of draught, salt and alkali and attracts more attention by its strong capacity in windbreak and sand-fixations. “Tamarix dunes” ... Tamarix plant is widely distributed in the arid areas of China for its great tolerance of draught, salt and alkali and attracts more attention by its strong capacity in windbreak and sand-fixations. “Tamarix dunes” constitute special desert bio-landscape in arid area. During last several decades,Tamarix shrubs declined and “Tamarix dunes” were also severely destroyed due to the land exploitation and serious deforestation, etc. From the 1980s until now, the extending phenomenon ofTamarix shrubs caused by developmental projects such as building highway, railway was studied in the western dry area of China, including western section of Hexi Corridor of Gansu, railroads and highways around the two greatest basin in Xinjiang and interior regions in Gurbantonggut desert, through on-the-spot survey along the transportation lines and setting up sampling plots along the roads. It was found that large quantities ofTamarix plants grow in the catchment area of low-lying lands that were formed by bulldozer operation during road building period. The extension ofTamarix shrubs caused by engineering was similar to that of the other section of the area to some extent, but went beyond the original distribution. This extension is beneficial to the ecological restoration and re-vegetation of western region of China and plays an important role in control of the sandstorms and improvement of ecological environments. As a result, it is necessary to make a further study on the extending phenomenon ofTamarix shrubs and to seek approach to promote wider extension ofTamarix shrubs in suitable habitats. Key words Arid area - Tamarix - Development engineering - Vegetation extension CLC number S718.541 Document code A Article ID 1007-662X(2004)01-0045-04 Foundation Item: This study is supported by key projects of National Natural Science Foundation (39730100), National Foundation (30070640) and part of Project 973(G19990435).Biography: Huang Pei-You (1936-), Male, Professor in College of Life Science and Technology, Xinjiang University, Urumqi, 830046Responsible editor: Chai Ruihai 展开更多
关键词 Arid area tamarix Development engineering Vegetation extension
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不同土壤水分条件下沙生柽柳(Tamarix taklamakanensis)的生理生化特征及适应性 被引量:10
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作者 苏志豪 周晓兵 +3 位作者 姜小龙 王留强 公延明 康晓珊 《干旱区研究》 CSCD 北大核心 2021年第1期198-206,共9页
沙生柽柳(Tamarix taklamakanensis)是我国特有种,是塔里木盆地流动沙丘上最抗旱树种,对固沙造林和荒漠化防治起到非常重要的作用。通过测定沙生柽柳种群在3种不同生境(沙漠公路绿化带、河床砾质荒漠、流动沙丘)的叶片含水量、叶绿素含... 沙生柽柳(Tamarix taklamakanensis)是我国特有种,是塔里木盆地流动沙丘上最抗旱树种,对固沙造林和荒漠化防治起到非常重要的作用。通过测定沙生柽柳种群在3种不同生境(沙漠公路绿化带、河床砾质荒漠、流动沙丘)的叶片含水量、叶绿素含量、抗氧化酶活性及渗透调节物质含量,探讨了沙生柽柳在不同生境下的生理生化特征及对荒漠极端干旱环境的适应机制。结果表明:随着土壤干旱程度的加剧,沙生柽柳叶片相对含水量逐渐下降;超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、总抗氧化能力(T-AOC)逐渐升高;过氧化氢酶(CAT)与硝酸还原酶(NR)活性逐渐降低;种群叶片内可溶性蛋白呈上升趋势。在最为干旱的流动沙丘,种群叶片叶绿素a含量、可溶性糖含量最高。在干旱胁迫条件下,沙生柽柳种群主要通过增高SOD活性、POD活性、总抗氧化能力及降低过氧化氢酶(CAT)、硝酸还原酶(NR)含量以维持活性氧代谢平衡;同时,通过大量积累渗透调节物质可溶性糖、可溶性蛋白、丙二醛以维持高渗透调节能力抵御干旱环境胁迫。 展开更多
关键词 沙生柽柳 抗氧化酶活性 渗透调节物质 生态适应性
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L型阵水下目标方位和距离联合最大似然估计 被引量:1
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作者 宋海岩 迟凤阳 唐弢 《黑龙江工程学院学报》 CAS 2024年第2期1-6,共6页
空间目标定位是阵列信号处理领域中的研究热点,广泛应用于雷达、声纳、通信、射电天文、医学诊断、地震遥感等众多领域。传统的水下声源定位仅获取目标声源的深度和距离信息,却无法估计目标的方位信息。针对这一问题,在充分考虑水下声... 空间目标定位是阵列信号处理领域中的研究热点,广泛应用于雷达、声纳、通信、射电天文、医学诊断、地震遥感等众多领域。传统的水下声源定位仅获取目标声源的深度和距离信息,却无法估计目标的方位信息。针对这一问题,在充分考虑水下声传播模型的基础上,利用L型阵列固有的结构特征,将最大似然估计技术应用到水下目标定位,提出一种基于L型水听器阵列的水下目标方位与距离联合最大似然估计算法。研究表明:最大似然估计法可有效突破传统波束形成分辨力“瑞利限”的限制,提高水下目标定位的分辨能力和精度。计算机仿真分析显示,在单目标和相干双目标的场景中,文中所提出的方法均具有更为尖锐的谱峰及更低的旁瓣水平,可对水下目标进行有效的方位角和距离联合估计。 展开更多
关键词 l型阵列 水下声传播 方位角及距离联合估计 最大似然估计法
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L波段差分干涉SAR卫星严格回归轨道优化设计方法
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作者 李楠 温俊健 +3 位作者 刘艳阳 凌惠祥 魏春 陈筠力 《测绘学报》 EI CSCD 北大核心 2024年第10期1873-1880,共8页
相比于传统SAR卫星应用方向,我国第一代L波段差分干涉SAR卫星主要用于实现全球精准地表形变测量。为了达到重轨差分干涉优于5 cm的形变测量指标,首先需要解决卫星空间基准轨道高精度回归的工程难题。对此,本文提出一种严格回归轨道优化... 相比于传统SAR卫星应用方向,我国第一代L波段差分干涉SAR卫星主要用于实现全球精准地表形变测量。为了达到重轨差分干涉优于5 cm的形变测量指标,首先需要解决卫星空间基准轨道高精度回归的工程难题。对此,本文提出一种严格回归轨道优化设计方法,通过地球重力场阶数需求分析建立卫星高阶动力学模型,将J4摄动下修正的太阳同步回归轨道参数作为优化算法初值,以卫星WGS-84坐标系位置、速度回归精度满足收敛阈值为目标,利用启发式多目标进化算法开展轨道参数寻优。仿真试验表明,寻优结果回归精度可达厘米级,优于既定工程指标,并且本文方法有效性和正确性已经过L波段差分干涉SAR卫星在轨验证。 展开更多
关键词 严格回归轨道 合成孔径雷达差分干涉 高阶重力场 优化轨道设计 l波段差分干涉SAR卫星
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316L不锈钢掺杂SiC环状同轴送粉TIG熔覆层组织结构与性能 被引量:1
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作者 高辉 周灿丰 +1 位作者 胡晓慧 李文龙 《焊接学报》 EI CAS CSCD 北大核心 2024年第4期49-56,I0006,共9页
TIG熔覆是经济高效的表面修复方法,与传统的预置粉末法相比,同轴送粉法具有优良的适应性,但是试验研究相对较少.自主设计制造了环状同轴送粉TIG熔覆焊枪,与管状同轴送粉TIG熔覆焊枪相比,制造的熔覆层不存在熄弧位置凹坑、焊缝不够平直... TIG熔覆是经济高效的表面修复方法,与传统的预置粉末法相比,同轴送粉法具有优良的适应性,但是试验研究相对较少.自主设计制造了环状同轴送粉TIG熔覆焊枪,与管状同轴送粉TIG熔覆焊枪相比,制造的熔覆层不存在熄弧位置凹坑、焊缝不够平直以及焊缝熔宽不一致等问题,而且具有更高的熔覆效率.结果表明,采用优化的焊接热输入、送粉量和SiC含量参数匹配,在316L不锈钢表面进行环状同轴送粉TIG熔覆,获得了外观优良的单层单道熔覆层、单层多道熔覆层.对熔覆层进行显微硬度测量、微观组织及元素成分分析、宏观电化学腐蚀试验、微区电化学腐蚀试验以及耐磨性能测试,并与母材进行了比对,环状同轴送粉TIG熔覆导入的SiC粉末有效地提升了熔覆层的耐蚀性与耐磨性. 展开更多
关键词 环状同轴送粉TIG熔覆 316l不锈钢 掺杂SiC 耐蚀性 耐磨性
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苦瓜皂苷L调控PI3K/AKT通路促进内皮祖细胞增殖能力和内皮功能的实验研究
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作者 黄建明 刘滴 +1 位作者 金道群 朱定君 《中西医结合心脑血管病杂志》 2024年第10期1768-1772,共5页
目的:探讨苦瓜皂苷L对内皮祖细胞(EPC)增殖能力和内皮功能的作用及机制。方法:体外分离、培养、鉴定外周血EPC。使用不同浓度苦瓜皂苷L处理EPC 24 h后,应用细胞计数试剂盒(CCK-8)法检测各组细胞活力。使用AutoDock Tools 5.6软件,分别... 目的:探讨苦瓜皂苷L对内皮祖细胞(EPC)增殖能力和内皮功能的作用及机制。方法:体外分离、培养、鉴定外周血EPC。使用不同浓度苦瓜皂苷L处理EPC 24 h后,应用细胞计数试剂盒(CCK-8)法检测各组细胞活力。使用AutoDock Tools 5.6软件,分别以磷脂酰肌醇3-激酶(PI3K)和蛋白激酶B(AKT)为受体,以药物分子苦瓜皂苷L为配体采用盲对接法进行分子对接。使用PI3K/AKT抑制剂LY294002和最佳使用浓度的苦瓜皂苷L单独或同时处理EPC 24 h后检测各组细胞活力和磷酸化PI3K(p-PI3K)、磷酸化AKT(p-AKT)及磷酸化内皮型一氧化氮合酶(p-eNOS)表达水平。结果:与对照组比较,苦瓜皂苷L呈剂量依赖性地促进EPC增殖,且40μmol/L的苦瓜皂苷L是最佳药物浓度。与对照组比较,LY294002可下调EPC细胞活力,苦瓜皂苷L可上调细胞活力。与苦瓜皂苷L组比较,共同使用苦瓜皂苷L和LY294002可降低细胞活力。分子对接结果显示,苦瓜皂苷L与PI3K和AKT均存在直接作用,形成稳定的锁钥结构。与对照组比较,LY294002可显著下调p-PI3K、p-AKT和p-eNOS蛋白水平;苦瓜皂苷L可上调p-PI3K、p-AKT和p-eNOS蛋白水平。与苦瓜皂苷L组比较,使用苦瓜皂苷L和LY294002可降低p-PI3K、p-AKT和p-eNOS蛋白水平。结论:苦瓜皂苷L通过PI3K/AKT信号通路靶向调节EPC的增殖能力,进而上调内皮型一氧化氮合酶(eNOS)活化水平以促进EPC内皮功能。 展开更多
关键词 内皮祖细胞 苦瓜皂苷l 细胞增殖 内皮功能 实验研究
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L型隔板弧形双钢板组合墙板抗爆性能试验与数值研究
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作者 赵春风 何凯城 +1 位作者 李晓杰 王静峰 《工程力学》 EI CSCD 北大核心 2024年第9期79-90,共12页
弧形双钢板混凝土组合墙板结构具有和拱结构相同的传力机理,可以充分发挥混凝土优异的抗压性能,极大地提高了结构的承载力。该文开展了L型隔板弧形双钢板混凝土组合墙板(L-shaped-Curved Double Steel Concrete Composite Wallboard,L-C... 弧形双钢板混凝土组合墙板结构具有和拱结构相同的传力机理,可以充分发挥混凝土优异的抗压性能,极大地提高了结构的承载力。该文开展了L型隔板弧形双钢板混凝土组合墙板(L-shaped-Curved Double Steel Concrete Composite Wallboard,L-CDSCW)在近场爆炸作用下的试验研究,通过混凝土的损伤分析和结构变形分析探究其抗爆性能。基于ANSYS/LS-DYNA软件进行了L-CDSCW试件爆炸响应的数值分析,参数化分析了不同关键参数对L-CDSCW试件抗爆性能的影响规律。结果表明:近场爆炸作用下,L-CDSCW试件未出现倒塌或崩塌现象,具有较强的抗爆性能;增加钢板厚度可以减小混凝土跨中凹陷深度和混凝土塑性破坏;增加TNT当量和降低爆距会显著增加底部钢板跨中最大挠度,同时也会增加混凝土跨中凹陷深度和混凝土损伤。研究结果可以为弧形双钢板混凝土组合板的应用提供一定的技术参考。 展开更多
关键词 近场爆炸 l型隔板弧形双钢板混凝土组合墙板 抗爆性能 试验研究 数值分析
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跗骨窦小切口与经外侧“L”形切口术对跟骨骨折患者的疗效
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作者 张磊 王宏 +2 位作者 张小伟 孟位明 赵志江 《河北医药》 CAS 2024年第15期2295-2299,共5页
目的 比较跗骨窦小切口与经外侧“L”形切口术治疗跟骨骨折的疗效及对足功能恢复情况的影响。方法 研究对象选取2020年10月至2022年10月收治的跟骨骨折患者88例,按照手术方法分为对照组43例,研究组45例,对照组采用经外侧“L”形切口术,... 目的 比较跗骨窦小切口与经外侧“L”形切口术治疗跟骨骨折的疗效及对足功能恢复情况的影响。方法 研究对象选取2020年10月至2022年10月收治的跟骨骨折患者88例,按照手术方法分为对照组43例,研究组45例,对照组采用经外侧“L”形切口术,研究组采用跗骨窦小切口手术。检测比较2组手术情况及并发症发生情况、足功能、跟骨解剖结构、骨代谢、炎性因子、应激反应指标水平。结果 与对照组比较,研究组术后引流量、术中出血量较少,手术、住院及骨折愈合时间较短,并发症发生率较低(P<0.05)。与术前比较,术后3个月2组AOFAS评分、Bohler角、Gissane角、跟骨长度、跟骨高度、P1NP、骨特异性碱性磷酸酶(BALP)水平升高,且研究组高于对照组,抗酒石酸酸性磷酸酶(TRAP)、环磷酰胺(CTX)水平降低,且研究组低于对照组(P<0.05)。与术前比较,术后3 d 2组CRP、IL-6、MDA水平升高,但研究组低于对照组,SOD水平降低,但研究组高于对照组(P<0.05)。结论 跗骨窦小切口术治疗跟骨骨折效果理想,可减少手术创伤,减轻炎症及应激反应,且可促进术后足功能、骨代谢恢复,并发症少。 展开更多
关键词 跟骨骨折 足功能 跗骨窦小切口 经外侧“l”形切口术
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