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1.
植物生长调节剂对杨树成花的效应   总被引:2,自引:0,他引:2  
温室环境下以不同药剂分别处理花枝的结果表明,不同剂量0.7、1、2、6000mg·L-1乙烯利(ETH)和100mg·L-1生长素(IAA)溶液可以有效促进小黑杨花枝蒴果凋落,凋落率分别达100%和76%;赤霉素(GA3)和多效唑(PP333)则否,或效果不理想.喷布比浇灌方式的控花效果好.  相似文献   
2.
用C-带和涂染技术检测棕色田鼠Y染色体   总被引:1,自引:0,他引:1  
采用染色体C 带技术和小鼠整条Y染色体特异探针检测棕色田鼠的Y染色体 ,结果如下 :棕色田鼠雄性个体C 带中期分裂相中 ,X性染色体是亚中部着丝粒染色体 ,在着丝粒处存在着强烈的C阳性带 ,而且在短臂的中间也有一条C阳性带 ,但是没有发现深染的Y染色体。用小鼠整条Y染色体特异探针涂染棕色田鼠的骨髓细胞中期分裂相和间期核 ,以小鼠骨髓细胞中期分裂相和间期核作为对照。涂染结果表明 :棕色田鼠骨髓细胞中期分裂相和间期核涂染信号检出率分别为 0 - 2 %和 3% - 5 % ,两者均呈阴性反应 ,而对照都呈阳性反应。根据实验结果 ,作者认为在棕色田鼠的Y染色体上及整个基因组DNA中不存在小鼠整条Y染色体特异DNA的同源序列 ,其Y染色体上可能没有决定雄性性别的重要基因  相似文献   
3.
A self‐healing polymer (SHP) with abundant hydrogen bonds, appropriate viscoelasticity, and stretchability is a promising binder to improve cycle performance of Si microparticle anodes in lithium (Li) ion batteries. Besides high capacity and long cycle life, efficient rate performance is strongly desirable for practical Si anode implementation. Here, polyethylene glycol (PEG) groups are incorporated into the SHP, facilitating Li ionic conduction within the binder. The concept of the SHP‐PEG binder involves improving the interface between Si microparticles and electrolytes after cycling based on the combination of self‐healing ability and fast Li ionic conduction. Through the systematic study of mixing PEG Mw and ratio, the polymeric binder combining SHP and PEG with Mw 750 in an optimal ratio of 60:40 (mol%) achieves a high discharging capacity of ≈2600 mA h g?1, reasonable rate performance especially when >1C and maintains 80% of their initial capacity even after ≈150 cycles at 0.5C. The described concept for the polymeric binder, embedding both self‐healing ability and high Li ionic conductivity, should be equally useful for next generation batteries utilizing high capacity materials which suffer from huge volume change during cycling.  相似文献   
4.
大豆黄酮抗氧化及抗癌作用   总被引:1,自引:0,他引:1  
大豆黄酮是异黄酮类化合物中最重要的生理活性物质。近年来发现它在促进生理机能、提高机体免疫力、抗氧化、抗癌方面的特殊功能使其成为研究热点。本文主要综述了大豆异黄酮的理化特性以及在抗氧化、抗癌等功能特性方面的最新研究进展,并根据当前研究现状对其应用前景和价值进行了展望。  相似文献   
5.
太原西山煤田太原组煤核中的科达植物雌性生殖器官   总被引:1,自引:0,他引:1  
报道了首次发现于我国的3种石化科达植物雌性生殖器官Cordaianthus sp.nov.,C.xishanensis sp.nov.和C.sp.,描述了它们的内部解剖构造特征,并与欧美植物区的雌性石化科达穗进行了比较,这些化石产于山西太原西山煤田太原组组上部7号煤层煤核中。  相似文献   
6.
曾勇 《古生物学报》1993,32(6):747-759
四川华蓥山地区二叠纪长兴期地层中共采获腕足动物90种44属,其中10新种,新亚种,根据这些丰富的化石材料,文章分析了该区长兴期腕足动物群的性质面貌,并与国内同期灰岩相腕足动物群进行了对比。同时对本区长兴期腕足动物的古生态进行了初步探讨,识别出两个腕足动物群落,,即Acosarina-Araxathyris群落和Perigeyerella群落。  相似文献   
7.
几种热激蛋白在细胞凋亡信号通路中的调控作用   总被引:3,自引:0,他引:3  
热激蛋白(heat shock proteins, HSPs)作为进化保守的蛋白家族 之一,普遍存在于各种生物体中,并在生物体内发挥着重要的生理功能.大 量的实验证据表明,热激蛋白与细胞凋亡密切相关,参与细胞凋亡信号通 路的多个环节. 近年来有关该领域的研究已获得了重要的突破与进展.一方 面,热激蛋白主要起着抑制细胞凋亡、促进细胞存活的作用;另一方面, 某些热激蛋白又能够作为凋亡蛋白的分子伴侣,促进细胞凋亡,比如HSP70 能够激活DNase来促使细胞凋亡,线粒体内HSP60能够促进caspase依赖的细 胞凋亡途径.本文在阐明细胞凋亡信号通路的基础上,综述了近年来几种不 同热激蛋白家族(HSP90、 HSP70 、HSP60和小分子HSPs)在细胞凋亡调控 中作用的研究进展,重点阐述了几种主要热激蛋白与细胞凋亡信号通路上 相关因子的相互作用,并绘制了热激蛋白在细胞凋亡信号通路中的调控图 ,为进一步完善细胞凋亡调控网络研究提供一定的参考.  相似文献   
8.
Persistent somatoform pain disorder (PSPD) is a mental disorder un-associated with any somatic injury and can cause severe somatosensory and emotional impairments in patients. However, so far, the neuro-pathophysiological mechanism of the functional impairments in PSPD is still unclear. The present study assesses the difference in regional spontaneous activity between PSPD and healthy controls (HC) during a resting state, in order to elucidate the neural mechanisms underlying PSPD. Resting-state functional Magnetic Resonance Imaging data were obtained from 13 PSPD patients and 23 age- and gender-matched HC subjects in this study. Kendall’s coefficient of concordance was used to measure regional homogeneity (ReHo), and a two-sample t-test was subsequently performed to investigate the ReHo difference between PSPD and HC. Additionally, the correlations between the mean ReHo of each survived area and the clinical assessments were further analyzed. Compared with the HC group, patients with PSPD exhibited decreased ReHo in the bilateral primary somatosensory cortex, posterior cerebellum, and occipital lobe, while increased ReHo in the prefrontal cortex (PFC) and default mode network (including the medial PFC, right inferior parietal lobe (IPL), and left supramarginal gyrus). In addition, significant positive correlations were found between the mean ReHo of both right IPL and left supramarginal gyrus and participants’ Self-Rating Anxiety Scale (SAS) scores, and between the mean ReHo of the left middle frontal gyrus and Visual Analogue Scale (VAS) scores. Our results suggest that abnormal spontaneous brain activity in specific brain regions during a resting state may be associated with the dysfunctions in pain, memory and emotional processing commonly observed in patients with PSPD. These findings help us to understand the neural mechanisms underlying PSPD and suggest that the ReHo metric could be used as a clinical marker for PSPD.  相似文献   
9.
外排泵基因过度表达促使细胞内的药物转移到细胞外,胞内药物浓度下降,致使药物临床疗效降低或无效。外排泵上有多个与识别底物结构无关的阴离子凹穴(底物结合位点),通过静电引力非特异性结合各种含阳离子的药物,在能量协助下将药物排到细胞外,进而导致细菌抗药性的产生。研究表明,结核杆菌基因组中存在外排泵基因,但仅分离到几个有功效的外排泵。本文就相关研究进展进行综述。  相似文献   
10.
1 Introduction Hydroxyapatite (HA), a very important bioceramic,is used extensively in medical applications for repair orreplacement of bone tissues [1–3]because HA is the mainmineral component of bone and teeth and forms a realbone with the surrounding bone tissue when implanted.However, because bulk HA exhibits poor mechanicalproperties, such as low strength and high brittleness, itcannot be used for implants that must withstand highloads [4, 5] . Therefore, for …  相似文献   
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