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Geomorphologic evidence of phased uplift of the northeastern Qinghai-Tibet Plateau since 14 million years ago 被引量:53
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作者 LU Huayu1, WANG Xiaoyong1, AN Zhisheng1, MIAO Xiaodong1, ZHU Rixiang3, MA Haizhou2, LI Zhen4, TAN Hongbing2 & WANG Xianyan1 1. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075 China 2. Qinghai Institute of Salt Lakes, Chinese Academy of Sciences. Xining 810008, China +1 位作者 3. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 4. Department of Geography, Qinghai Normal University, Xining 810008, China 《Science China Earth Sciences》 SCIE EI CAS 2004年第9期822-833,共12页
A typical sequence of fluvial terraces and aeolian deposits overlying these ter- races were multidisciplinary investigated. New evidences for uplift process of the northeastern Qinghai-Tibetan Plateau in the past 14 m... A typical sequence of fluvial terraces and aeolian deposits overlying these ter- races were multidisciplinary investigated. New evidences for uplift process of the northeastern Qinghai-Tibetan Plateau in the past 14 million years were obtained. At least 11 river terraces along Huangshui, the first-class tributary of Yellow River, at the Xining-Huzhu region are identi- fied. While the first one (T1) is classified as an accumulation terrace, the others are all basement river terraces, which consist of the Tertiary sandstone and siltstone bedrock, fluvial gravel and pebbles and the overlying aeolian loess-Red Clay deposit. Samples from the aeolian deposits were examined for paleomagnetic stratigraphic reconstruction (1030 samples), luminescence dating (16 samples), magnetic susceptibility and grain-size distribution (more than 4000 sam- ples). The luminescence dating and stratigraphic correlation suggest that terraces of Tll, T10, T8, T7, T3, T2, T1 were formed at 14, 11.3, 1.55, 1.2, 0.15, 0.07 and 0.01 million years ago, re- spectively. Sedimentological analysis and geomorphological observation indicate that formation and evolution of these terraces were mainly driven by tectonic uplift. Therefore, the terrace se- quence provides an ideal geological record, of the uplift process of the northeastern during the past 14 million years, and the timings of the terraces formation are regarded as the timings of tectonic uplift. The significant uplifting events took place at 14, 11.3, 1.2 and 0.15 mil- lion years ago, respectively. The fluvial incision at the Xining-Huzhu region is less than 100 m during a period of ~12 million years in the Miocene era (between the Tll and T9), while the Huangshui River had incised 432 m during the past 1.2 million years (from T7 to the present floodplain). The river incision process clearly demonstrates that accelerated rising of the north- eastern Qinghai-Tibet Plateau during the late Cenozoic, and provides new evidence of previous thoughts. There was a significant readjustment of the fl 展开更多
关键词 river terrace tectonic uplift loess-Red Clay the past 14 MILLION years northeastern Qinghai-Tibet Plateau.
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套细胞淋巴瘤石蜡包埋组织中细胞周期蛋白D1和t(11;14)易位检测的临床病理意义 被引量:21
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作者 水若鸿 杨文涛 +2 位作者 孙孟红 施达仁 朱雄增 《中华病理学杂志》 CAS CSCD 北大核心 2003年第4期337-341,共5页
目的 探讨套细胞淋巴瘤石蜡包埋组织中细胞周期蛋白 (cyclin)D1和t(11;14 )易位检测的可行性及其诊断和鉴别诊断价值。方法 收集套细胞淋巴瘤 36例 ,对照组小B细胞恶性淋巴瘤71例 ,均为石蜡包埋组织 ,运用免疫组织化学方法观察cyclinD... 目的 探讨套细胞淋巴瘤石蜡包埋组织中细胞周期蛋白 (cyclin)D1和t(11;14 )易位检测的可行性及其诊断和鉴别诊断价值。方法 收集套细胞淋巴瘤 36例 ,对照组小B细胞恶性淋巴瘤71例 ,均为石蜡包埋组织 ,运用免疫组织化学方法观察cyclinD1的表达 ;用半巢式聚合酶链反应(PCR)法检测t(11;14 )易位 ,以看家基因 β 肌动蛋白 (actin)作为内对照检测DNA质量。 结果  (1)36例套细胞淋巴瘤中 2 6例 (72 2 % )表达cyclinD1,对照组无 1例表达。 (2 ) 10 7例标本中 10 1例(94 4 % )可检出 β actinDNA表达。 36例套细胞淋巴瘤中 2 2例检出t(11;14 )易位 ,对照组无 1例检出。去除 β actin和t(11;14 )易位均阴性 2例 ,套细胞淋巴瘤中t(11;14 )易位检出率为 6 4 7%。 (3)36例套细胞淋巴瘤中cyclinD1染色和 (或 )t(11;14 )易位检测阳性病例为 2 9例 ,总阳性率为 80 5 %。结论 套细胞淋巴瘤石蜡包埋组织中cyclinD1和t(11;14 )易位的检测具较高的特异性和可行性 。 展开更多
关键词 套细胞淋巴瘤 石蜡包埋组织 细胞周期蛋白 D1 t(11 14) 蛋白易位 临床病理学
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Plant xylem hydraulics:What we understand,current research,and future challenges 被引量:18
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作者 Martin D. Venturas John S. Sperry Uwe G. Hacke 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2017年第6期356-389,共34页
Herein we review the current state-of-the-art of plant hydraulics in the context of plant physiology, ecology, and evolution, focusing on current and future research opportunities. We explain the physics of water tran... Herein we review the current state-of-the-art of plant hydraulics in the context of plant physiology, ecology, and evolution, focusing on current and future research opportunities. We explain the physics of water transport in plants and the limits of this transport system, highlighting the relationships between xylem structure and function. We describe the great variety of techniques existing for evaluating xylem resistance to cavitation. We address several methodological issues and their connec- tion with current debates on conduit refilling and exponentially shaped vulnerability curves. We analyze the trade-offs existing between water transport safety and efficiency. We also stress how little information is available on molecular biology of cavitation and the potential role of aquaporins in conduit refilling. Finally, we draw attention to how plant hydraulic traits can be used for modeling stomatal responses to environmental variables and climate change, including drought mortality. 展开更多
关键词 William J. Lucas University of California Davis USAReceived Jan. 10 2017 Accepted Mar. 9 2017 Online on Mar. 14 2017
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健康体检人群幽门螺杆菌感染情况分析 被引量:16
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作者 张筱辉 陈红华 杨光 《中国社会医学杂志》 2017年第3期313-315,共3页
目的了解健康体检人群中幽门螺杆菌感染率的检出情况,分析其影响因素,为预防幽门螺杆菌感染提供理论参考。方法于2015年7月—2016年6月对在某医院体检中心进行健康体检的人群进行流行病资料调查,纳入916例用14 C-尿素呼气试验检测幽门... 目的了解健康体检人群中幽门螺杆菌感染率的检出情况,分析其影响因素,为预防幽门螺杆菌感染提供理论参考。方法于2015年7月—2016年6月对在某医院体检中心进行健康体检的人群进行流行病资料调查,纳入916例用14 C-尿素呼气试验检测幽门螺杆菌感染情况的受检者。运用卡方检验和多因素Logistic回归进行统计分析。结果 916例体检者的幽门螺杆菌总感染率为41.70%,单因素分析结果显示,男性感染率高于女性,不同年龄组幽门螺杆菌感染率差异有统计学意义(P<0.05);城市地区感染率低于农村(P<0.05);吸烟、饮酒和有消化道症状的患者感染率明显高于无相关因素者(P<0.05)。多因素分析结果显示,男性、农村地区居住、吸烟与饮酒史以及有消化道症状等是幽门螺杆菌感染的危险因素。结论男性、居住地区、吸烟与饮酒史以及是否有消化道症状等因素与幽门螺杆菌的感染率均呈正相关。 展开更多
关键词 健康体检 幽门螺杆菌 14 C-尿素呼气试验 相关因素
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Regulation of Rice Tillering by RNA-Directed DNA Methylation at Miniature Inverted-Repeat Transposable Elements 被引量:16
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作者 Le Xu Kun Yuan +5 位作者 Meng Yuan Xiangbing Meng Min Chen Jianguo Wu Jiayang Li Yijun Qi 《Molecular Plant》 SCIE CAS CSCD 2020年第6期851-863,共13页
Tillering is a major determinant of rice plant architecture and grain yield.Here,we report that depletion of rice OsNRPD1a and OsNRPD1b,two orthologs of the largest subunit of RNA polymerase IV,leads to a high-tilleri... Tillering is a major determinant of rice plant architecture and grain yield.Here,we report that depletion of rice OsNRPD1a and OsNRPD1b,two orthologs of the largest subunit of RNA polymerase IV,leads to a high-tillering phenotype,in addition to dwarfism and smaller panicles.OsNRPD1a and OsNRPD1b are required for the production of 24-nt small interfering RNAs that direct DNA methylation at transposable elements(TEs)including miniature inverted-repeat TEs(MITEs).Interestingly,many genes are regulated either positively or negatively by TE methylation.Among them,OsMIR156d and OsMIR156j,which promote rice tillering,are repressed by CHH methylation at two MITEs in the promoters.By contrast,D14,which suppresses rice tillering,is activated by CHH methylation at an MITE in its downstream.Our findings reveal regulation of rice tillering by RNA-directed DNA methylation at MITEs and provide potential targets for agronomic trait enhancement through epigenome editing. 展开更多
关键词 RDDM siRNA MITES OsMIR156 D14 TILLER
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Changes of the cytokine profile in inflammatory bowel diseases 被引量:16
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作者 Gyrgyi Mzes Béla Molnár +1 位作者 Zsolt Tulassay Ferenc Sipos 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第41期5848-5861,共14页
Cytokines are indispensable signals of the mucosaassociated immune system for maintaining normal gut homeostasis.An imbalance of their profile in favour of inflammation initiation may lead to disease states,such as th... Cytokines are indispensable signals of the mucosaassociated immune system for maintaining normal gut homeostasis.An imbalance of their profile in favour of inflammation initiation may lead to disease states,such as that is observed in inflammatory bowel diseases(IBD).Although Crohn's disease(CD) is often described as a prototype of T-helper 1-type diseases,and ulcerative colitis(UC) is traditionally viewed as a T-helper 2-mediated condition,the classic paradigm,which categorises cytokines into pro-and anti-inflammatory groups,has recently been changed.The inflammation regulatory pathways may not be mutually exclusive as individual cytokines can have diverse and even opposing functions in various clinical and immunological settings.None the less there are many common immunological responses in IBD that are mediated by cytokines.Although they regulate and influence the development,course and recurrence of the inflammatory process,the concrete pathogenic role of these small signaling molecules is sometimes not unambiguous in the subtypes of the disease.Our aim is to review the current information about pro-and anti-inflammatory effects of traditionally studied and recently discovered cytokines in the pathogenesis of UC and CD.The better understanding of their production and functional activity may lead to the development of new therapeutic modalities. 展开更多
关键词 Ulcerative colitis Crohn's disease Interleu-kin-33 Tumor necrosis factor-like factor INTERLEUKIN-8 Interleukin-35 INTERLEUKIN-25 INTERLEUKIN-4 Tumornecrosis factor ligand superfamily member 14
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南通地区人群幽门螺旋杆菌感染状况及相关因素分析 被引量:15
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作者 凌霞 钱进 田尧 《公共卫生与预防医学》 2021年第5期141-144,共4页
目的分析南通地区体检人群幽门螺旋杆菌(Hp)感染状况以及相关因素。方法通过整群抽取2020年6月至2021年2月在南通地区某医院1680例健康体检者作为调查对象。通过14 C-尿素呼气试验进行Hp感染检测,采用该院自制的自填式和询问式问卷调查... 目的分析南通地区体检人群幽门螺旋杆菌(Hp)感染状况以及相关因素。方法通过整群抽取2020年6月至2021年2月在南通地区某医院1680例健康体检者作为调查对象。通过14 C-尿素呼气试验进行Hp感染检测,采用该院自制的自填式和询问式问卷调查收集研究对象一般资料,采用多因素logistic回归分析影响南通地区体检人群Hp感染的相关因素。结果1680名体检人员中,Hp感染阳性人数980例,总体感染阳性率58.33%。经单因素分析结果发现,Hp感染与南通地区体检人群年龄、饮酒、嗜辣、经常进食腌制食品、家族胃癌史、慢性胃炎有关(P<0.05)。多因素logistic回归析结果显示,年龄>60岁(OR=3.46,95%CI:1.35~8.84)、饮酒(OR=5.22,95%CI:2.79~9.77)、嗜辣(OR=5.47,95%CI:2.45~9.30)、经常进食腌制食品(OR=5.28,95%CI:3.48~7.92)、家族胃癌史(OR=4.29,95%CI:2.86~76.45)、慢性胃炎(OR=5.07,95%CI:2.79~9.22)均为影响Hp感染的相关因素(P<0.05)。结论南通地区体检人群Hp感染阳性率较高,并且与年龄、饮酒、嗜辣、经常吃腌制食品、家族胃癌史、慢性胃炎等因素有关。 展开更多
关键词 幽门螺旋杆菌感染 体检人群 南通地区 14 C-尿素呼气试验
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高灵敏度的快中子照相系统 被引量:15
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作者 章法强 杨建伦 +6 位作者 李正宏 钟耀华 叶凡 秦义 陈法新 应纯同 刘广均 《物理学报》 SCIE EI CAS CSCD 北大核心 2007年第1期583-588,共6页
快中子照相系统由闪烁光纤阵列和科学级可见光CCD等元件组成.14MeVD-T聚变中子在穿透样品后进入50mm×50mm闪烁光纤阵列,中子辐射转换为中心波长496nm的绿光.光纤阵列长100mm,光纤截面500μm×500μm,100×100根闪烁体光纤... 快中子照相系统由闪烁光纤阵列和科学级可见光CCD等元件组成.14MeVD-T聚变中子在穿透样品后进入50mm×50mm闪烁光纤阵列,中子辐射转换为中心波长496nm的绿光.光纤阵列长100mm,光纤截面500μm×500μm,100×100根闪烁体光纤组成阵列.阵列对14MeV中子探测效率经估算可达21·4%.CCD与光纤阵列之间采用反射镜和透镜耦合方式,使CCD避开中子源直接辐照.综合考虑光纤尺寸、CCD记录噪声及中子源与受照样品几何关系等因素,理论上系统可获得整体分辨率1·5mm的中子图像.在K400直流加速器中子源上进行了初步实验,获得了中子图像. 展开更多
关键词 14 MeV中子 射线照相 闪烁光纤阵列
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超临界流体色谱法分离二十碳五烯酸和二十二碳六烯酸 被引量:11
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作者 任其龙 熊任天 +1 位作者 王宪达 吴平东 《分析化学》 SCIE EI CAS CSCD 北大核心 2001年第9期1076-1078,共3页
以二氧化碳单一作流动相,ODS柱为固定相,用超临界流体色谱法分离了二十碳五烯酸(EPA)和二十二碳六烯酸(DHA),考察了操作温度和压力对容量因子(k′)和分离度(R)的影响,并根据EPA和DHA在超临界二氧化碳中溶解度的变化规律,对实验结果做... 以二氧化碳单一作流动相,ODS柱为固定相,用超临界流体色谱法分离了二十碳五烯酸(EPA)和二十二碳六烯酸(DHA),考察了操作温度和压力对容量因子(k′)和分离度(R)的影响,并根据EPA和DHA在超临界二氧化碳中溶解度的变化规律,对实验结果做了定性的解释。 展开更多
关键词 超临界流体色谱法 二十碳五烯酸 二十二碳六烯酸 不饱和脂肪酸 鱼油 分离
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Effect of catgut implantation at acupoints on GABA_B and mGluR1 expressions in brain stem of rats with spasticity after stroke 被引量:13
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作者 Chengmei Liu Ruiqing Li +1 位作者 Xiaolei Song Xiaodong Feng 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2014年第5期566-571,共6页
OBJECTIVE: To investigate the effect of catgut implantation at acupoints on the expressions of γ-amino butyric acid B receptor(GABAB ) and metabotropic glutamate receptor 1(mGluR1) in the brain stem of rats with spas... OBJECTIVE: To investigate the effect of catgut implantation at acupoints on the expressions of γ-amino butyric acid B receptor(GABAB ) and metabotropic glutamate receptor 1(mGluR1) in the brain stem of rats with spasticity after stroke.METHODS: In total, 60 male Sprague-Dawley rats were randomly divided into three groups: a sham group(n=10), a model group(n=25) and a treatment group(n=25). The rats in both the model group and the treatment group were subjected to middle cerebral artery occlusion to establish a model of focal cerebral ischemia. Rats with limb-spasm met the inclusion criteria. Only the left carotid artery was isolated in sham group rats. Three days after modeling, the treatment group was subjected to catgut implantation at Dazhui(GV 14), Guanyuan(CV 4), and Zhongwan(CV 12). Neurological deficit symptoms were assessed with the Zea-Longa neurological deficit score. The Modified Ashworth Scale(MAS), and isolated muscle tone were used to evaluate spasticity before and after treatment. Immunohistochemistry was applied to determine the expression of GABAB and mGluR1 in the rat brain stem after treatment.RESULTS: After treatment, neural impairment symptoms had significantly improved in the treatment group when compared to the model group(P<0.05). Both MAS and isolated muscle tone in the treatment group were significantly decreased when compared with the model group(P<0.05),and were also lower than before treatment. GABAB expression was significantly higher and mGluR1 was lower in the treatment group when compared with the model group(P<0.01 and P<0.05, respectively).CONCLUSION: Catgut implantation at Dazhui(GV 14), Guanyuan(CV 4), and Zhongwan(CV 12), can relieve limb spasticity by increasing the expression of GABAB and reducing the expression of mGluR1 in the brain stem of rats after stroke. 展开更多
关键词 STROKE Muscle spasticity Embeddingtherapy Point GV 14 (Dazhui) Point CV 4 (Guanyu-an) Point CV 12 (Zhongwan) Metabotropic gluta-mate receptor type 1
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正常妊娠和原因不明习惯性流产者HLA-G基因14bp缺失多态性研究 被引量:12
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作者 薛松果 杨珏琴 +2 位作者 姚芳娟 许玲娣 范丽安 《现代免疫学》 CAS CSCD 北大核心 2006年第4期318-321,共4页
为研究HLA-G基因3’非翻译区14 bp缺失多态性在习惯性流产患者和正常妊娠妇女中的差异,分别提取患者蜕膜和正常女性外周血DNA。PCR扩增HLA-G基因第8外显子,产物经9%非变性聚丙烯酰胺凝胶电泳分离,并经EB染色后在凝胶成像仪下观察。显著... 为研究HLA-G基因3’非翻译区14 bp缺失多态性在习惯性流产患者和正常妊娠妇女中的差异,分别提取患者蜕膜和正常女性外周血DNA。PCR扩增HLA-G基因第8外显子,产物经9%非变性聚丙烯酰胺凝胶电泳分离,并经EB染色后在凝胶成像仪下观察。显著性检验用SAS软件包进行四格表χ2分析。结果显示:(1)-14 bp和+14 bp等位基因频率在两组间无显著性差异;(2)与正常对照组相比,RSA患者组中-14 bp/+14 bp杂合子的比例显著升高(χ2=4.7690,P=0.0290)。结果提示,中国人群HLA-G 14 bp缺失多态性在维持正常的妊娠中可能有重要作用。 展开更多
关键词 HLA-G 14 bp缺失多态性 习惯性流产
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Genomics of hepatitis B virus-related hepatocellular carcinoma and adjacent noncancerous tissues with cDNA microarray 被引量:11
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作者 HUANG Yu-kun FAN Xue-gong +1 位作者 QIU Fu WANG Zhi-ming 《Chinese Medical Journal》 SCIE CAS CSCD 2011年第13期2057-2064,共8页
Background Hepatocellular carcinoma (HCC) is a common primary cancer frequently associated with hepatitis B virus (HBV) infection. However, whether these identified genes are particularly associated with HBV-relat... Background Hepatocellular carcinoma (HCC) is a common primary cancer frequently associated with hepatitis B virus (HBV) infection. However, whether these identified genes are particularly associated with HBV-related HCC remains unknown. The aim of this study was to investigate the differential gene expression between HBV-related HCC tissues and adjacent noncancerous tissues. Methods cDNA microarray was used to detect the differential gene expression profile in the HBV-related HCC tissues and adjacent noncancerous tissues, and reverse transcription-polymerase chain reaction (RT-PCR) was performed to verify the differential expression of candidate genes obtained from cDNA microarray experiment. Results In this study, 1369 genes or expressed sequence tags (ESTs) including 121 genes or ESTs with at least two-fold expression alterations between cancerous and noncancerous tissues were identified. Special AT-rich sequence binding protein 1 (SATB-1) expression was positive in 73% (16/22) of cancerous tissues and negative (0/22) in all noncancerous tissues of HBV-related HCC patients. Transmembrane 4 superfamily member 1 (TM4SF-1) expression was positive in 86% (19/22) of cancerous tissues and negative (0/22) in all noncancerous tissues. Suppression of tumorigenicity 14 (ST-14) expression was positive in 73% (16/22) of noncancerous tissues in patients with HBV-related HCC and negative in all HCC tissues (0/22). Conclusion This study provided the gene expression profile of HBV-related HCC and presented differential expression patterns of SATB-1, TM4SF-1 and ST-14 between cancerous and noncancerous tissues in patients with HBV-related HCC. 展开更多
关键词 special AT-rich sequence-binding protein 1 human transmembrane 4 superfamily member 1 suppression of tumorigenicity 14 protein carcinoma hepatocellular microarray analysis
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t(14;21)平衡易位携带者体细胞和生殖细胞的细胞遗传学研究(英文) 被引量:10
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作者 唐艳平 刘秀生 +3 位作者 刘媛 杨真荣 陈燕 熊承良 《Acta Genetica Sinica》 SCIE CAS CSCD 北大核心 2006年第6期488-494,共7页
15%-20%的妊娠因为自发流产而中止,其中约50%是因为染色体异常所致。夫妇中的一方为平衡的染色体异常携带者时,即可能产生不平衡的配子和胚胎,临床症状可以有不同程度的变化:如不育、反复流产、甚至产出染色体综合症的患儿。以临床接诊... 15%-20%的妊娠因为自发流产而中止,其中约50%是因为染色体异常所致。夫妇中的一方为平衡的染色体异常携带者时,即可能产生不平衡的配子和胚胎,临床症状可以有不同程度的变化:如不育、反复流产、甚至产出染色体综合症的患儿。以临床接诊的一对具有反复自然流产史夫妇为研究对象,常规进行精液、激素水平检测。取患者外周血淋巴细胞用RPMI1640培养基进行短期培养,经低渗、固定处理制备染色体标本片,对染色体数目和结构进行核型分析。选用特异的21qter和14qterDNA标记作为探针,对患者外周血淋巴细胞中期染色体进行FISH分析。运用FISH技术对患者精子细胞进行研究,配合流式细胞分析技术对精细胞DNA组份进行检测,分析配子中遗传物质的组成及各种类型配子的比例。结果发现女方核型正常为46,XX,男方核型为罗伯逊易位的携带者45,XY,-14,-21,+t(14;21)。患者外周血体细胞的分裂相染色体FISH显示一个细胞中分别存在1个红色的21qter和1个绿色的14qter杂交信号,另外有1个红色和1个绿色信号共同存在于一条由易位形成的亚中着丝粒染色体上。在患者精液样本的精细胞FISH研究中,可以观察到5种不同类型的杂交信号,异常的配子的种类与理论推断相同,但各型所占的比例有其特点,结合精液中精细胞流式细胞术的分析表明,平衡的单倍体配子占71%,不平衡的配子占29%。通过国内外文献资料统计,对罗伯逊易位染色体的常见和罕见类型进行综述,为其生育的临床治疗方案提供建议。 展开更多
关键词 t(14 21) 体细胞 精子 染色体 FISH 流式细胞术
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基于FilterPro的有源滤波器的快速设计与分析 被引量:10
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作者 张涛 郑大威 《现代电子技术》 北大核心 2016年第8期115-117,121,共4页
在当今的电信设备和各类控制系统中,滤波器应用极为广泛,滤波器的优劣直接决定产品的优劣,其中有源滤波器的应用更为灵活和方便。针对有源滤波器两种常见的拓扑结构:多路反馈型(MFB)和压控电源型(Sallen-Key),对两种滤波器的传递函数进... 在当今的电信设备和各类控制系统中,滤波器应用极为广泛,滤波器的优劣直接决定产品的优劣,其中有源滤波器的应用更为灵活和方便。针对有源滤波器两种常见的拓扑结构:多路反馈型(MFB)和压控电源型(Sallen-Key),对两种滤波器的传递函数进行推导和分析。利用德州仪器公司的滤波器设计软件FilterPro,按照两种拓扑结构设计基于巴特沃斯的有源滤波器,并用Multisim 14对设计的两种滤波器进行仿真和验证,为今后有源滤波器的设计与应用提供一定理论基础。 展开更多
关键词 有源滤波器 MFB Sallen-Key 拓扑结构 FilterPro MULTISIM 14
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0.14 THz折叠波导行波管的设计与实验 被引量:10
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作者 雷文强 蒋艺 +3 位作者 胡林林 阎磊 马国武 陈洪斌 《太赫兹科学与电子信息学报》 2014年第3期334-338,共5页
对折叠波导慢波结构进行了研究,对其色散特性和耦合阻抗进行分析,并设计了输能窗和电子光学系统,在此基础上进行了粒子模拟的束波互作用计算。通过设计,对0.14 THz行波管进行了制管工艺的研究,包括慢波结构的加工和焊接等,完成了热测实... 对折叠波导慢波结构进行了研究,对其色散特性和耦合阻抗进行分析,并设计了输能窗和电子光学系统,在此基础上进行了粒子模拟的束波互作用计算。通过设计,对0.14 THz行波管进行了制管工艺的研究,包括慢波结构的加工和焊接等,完成了热测实验。在电压为16.3 kV,电子流通率为74%条件下,测试得到最大饱和输出功率3.1 W,输出频率140.08 GHz,增益27 dB,最大功率半带宽2.82 GHz。 展开更多
关键词 折叠波导慢波结构 0 14 THz行波管 输能窗 热测实验 电子流通率
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Adsorption behavior of Azo Dye C. I. Acid Red 14 in aqueous solution on surface soils 被引量:8
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作者 QU Baocheng ZHOU Jiti XIANG Xuemin ZHENG Chunli ZHAO Hongxia ZHOU Xiaobai 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第6期704-709,共6页
Azo dyes have received considerable attention because of their association with various human health problems. The aim of the investigation is to determine the adsorption behavior ofazo dyes in aqueous solution on DG0... Azo dyes have received considerable attention because of their association with various human health problems. The aim of the investigation is to determine the adsorption behavior ofazo dyes in aqueous solution on DG06, GSE17200, and GSE17201 soils using C. I. Acid Red 14 (AR14) as example. The experimental results indicate that the Freundlich model expresses the adsorption isotherm better than the Langmuir model and the pseudo-second-order model achieves adsorption of AR14 on the three soils well. Based on the pseudo-second-order model, the adsorption thermodynamic of AR14 on DG06 soil have been studied and the thermodynamics parameter of AGO is determined and AGO value shows the adsorption process of AR14 on DG06 is mainly physical in nature. Furthermore, the effects of temperature, pH and salinity (NaC1) on adsorption have been investigated. The decrease in pH or the increase in salinity enhances the adsorption of AR14 by DG06, GSE17200, and GSE17201. 展开更多
关键词 SOIL azo dyes C. I. Acid Red 14 (AR14 adsorption isotherm adsorption kinetics adsorption thermodynamics
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miR-124-3p靶向调控MAPK 14对子痫前期大鼠胎盘滋养层细胞增殖及侵袭的影响 被引量:9
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作者 周俏苗 汪洪林 +4 位作者 黄海燕 许晶 肖美芳 龚护民 吴栋才 《中国比较医学杂志》 CAS 北大核心 2020年第6期1-9,共9页
目的探讨miR-124-3p通过靶向调控MAPK 14,从而对子痫前期大鼠胎盘滋养层细胞增殖与侵袭产生作用。方法提取正常大鼠及模型大鼠胎盘滋养层组织及原代细胞,分组转染。MTT、流式细胞术、Transwell检测检测细胞活力、凋亡、周期、迁移及侵... 目的探讨miR-124-3p通过靶向调控MAPK 14,从而对子痫前期大鼠胎盘滋养层细胞增殖与侵袭产生作用。方法提取正常大鼠及模型大鼠胎盘滋养层组织及原代细胞,分组转染。MTT、流式细胞术、Transwell检测检测细胞活力、凋亡、周期、迁移及侵袭能力,qRT-PCR及Western blot检测因子的表达水平。验证miR-124-3p和MAPK 14的靶向关系。结果过表达miR-124-3p后,细胞增殖、侵袭能力降低,细胞阻滞在G1/G0期,细胞凋亡增加;抑制miR-124-3p表达后,结果相反。双荧光素酶报告实验显示miR-124-3p与MAPK 14存在靶向关系。抑制MAPK 14表达后,与过表达miR-124-3p结果一致,细胞活力及侵袭能力降低,凋亡增加;过表达MAPK 14实验组与抑制miR-124-3p表达结果一致。结论 miR-124-3p可靶向负调控MAPK 14,对子痫前期大鼠胎盘滋养层细胞的增殖与侵袭产生影响。 展开更多
关键词 miR-124-3p MAPK 14 子痫前期 滋养层细胞 增殖 侵袭
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bcl-2与bcl-6在弥漫性大B细胞淋巴瘤中表达的研究 被引量:9
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作者 王国平 郗彦凤 +2 位作者 李义 王晋芬 白纬 《白血病.淋巴瘤》 CAS 2009年第10期588-591,共4页
目的从蛋白水平和基因水平研究bcl-2、bcl-6在弥漫性大B细胞淋巴瘤(DLBCL)的表达。方法应用免疫组织化学EnVision法对73例DLBCL进行CD3、CD10、CD20、bcl-2、bcl-6、MUM-1的标记。应用荧光原位杂交(FISH)技术检测其中57例t(14;18... 目的从蛋白水平和基因水平研究bcl-2、bcl-6在弥漫性大B细胞淋巴瘤(DLBCL)的表达。方法应用免疫组织化学EnVision法对73例DLBCL进行CD3、CD10、CD20、bcl-2、bcl-6、MUM-1的标记。应用荧光原位杂交(FISH)技术检测其中57例t(14;18)染色体异位bcl-2基因的异常情况和54例bcl-6基因所在的3q27染色体的断裂和扩增情况。结果肿瘤细胞表达CD10、bcl-6、MUM-1、bcl-2的阳性率分别为15.1%、38.4%、71.2%、79.2%。57例患者中16例(28.1%)存在t(14;18)。bcl-2蛋白表达与免疫学亚型有相关性(P=0.035),t(14;18)与预后有相关性(P=0.045),t(14;18)与bcl-2蛋白表达无相关性(P=0.710)。54例中3q27染色体断裂11例(20.4%),扩增14例(25.9%)。bcl-6阳性表达较阴性者预后好(P=0.041)。bcl-6与3q27断裂和扩增无相关性(均P=1.000)。结论bcl-2、bcl-6蛋白和基因表达是各自独立的事件,它们在DLBCL中的意义不同。bcl一2蛋白是与免疫学亚型相关的预后标志物,bcl-2阳性的GCB型预后较差;t(14;18)是独立预后事件,阳性者预后较差,对靶向治疗患者应检测t(14;18);bcl-6蛋白的表达有助于DLBCL的预后判断,可作为独立的预后因子。3q27染色体断裂可能提示预后较差。 展开更多
关键词 淋巴瘤 大细胞 弥漫型 基因 BCL-2 基因 bcl-6 原位杂交 荧光 t(14 18) 3q27 预后
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14MeV中子照相中散射中子对成像影响的Monte Carlo模拟 被引量:9
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作者 章法强 杨建伦 +2 位作者 李正宏 应纯同 刘广均 《物理学报》 SCIE EI CAS CSCD 北大核心 2007年第6期3577-3583,共7页
依据实验参数,建立了14MeV快中子照相的物理模型,并利用Monte Carlo方法对照相过程进行了模拟.分析了经聚乙烯样品散射的中子对快中子图像的影响随样品与探测器间距及样品参数的变化.计算结果表明,样品与探测器的距离d<5cm时,样品中... 依据实验参数,建立了14MeV快中子照相的物理模型,并利用Monte Carlo方法对照相过程进行了模拟.分析了经聚乙烯样品散射的中子对快中子图像的影响随样品与探测器间距及样品参数的变化.计算结果表明,样品与探测器的距离d<5cm时,样品中的散射中子对图像的影响强烈依赖于d,而当d>20cm时,样品散射中子对图像的影响可忽略;当样品密度为3—5g/cm3时散射中子对图像的影响相对最大;样品宽度越大,图像中的散射成分越多,当宽度在3cm以上时散射成分的强度趋于饱和. 展开更多
关键词 14 MeV中子 快中子照相 散射中子 MONTE CARLO模拟
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虚拟仿真软件在中学物理实验教学中的应用——以高中物理实验“伏安法测电阻”为例 被引量:5
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作者 刘芷余 秦宇飞 柴万东 《赤峰学院学报(自然科学版)》 2023年第6期60-63,共4页
物理学是以实验为基础的自然科学,实验教学是高中物理教学的基础与主题。在教育信息化的浪潮下,虚拟仿真实验作为一种以虚拟仿真技术为支撑的实验教学新形式,通过图形化界面模拟实物实验的过程与效果,帮助学生直观、形象地体验实验操作... 物理学是以实验为基础的自然科学,实验教学是高中物理教学的基础与主题。在教育信息化的浪潮下,虚拟仿真实验作为一种以虚拟仿真技术为支撑的实验教学新形式,通过图形化界面模拟实物实验的过程与效果,帮助学生直观、形象地体验实验操作过程,具有沉浸式、高仿真、突破时间和空间的限制等特点,与传统实验相互补充,是目前国家推进现代信息技术融入实验教学的重点项目。为了提高物理实验的教学效果,培养学生的创新学习能力,形成严谨的、实事求是的世界观,本文以高中物理实验“伏安法”测电阻为例,利用Multisim 14.0进行虚拟仿真,对虚拟仿真实验在高中物理教学中的应用进行探讨。 展开更多
关键词 虚拟仿真实验 中学物理实验教学 Multisim 14.0
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