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1.
矿石可选性预测专家系统(OBPES)通用骨架系统是选矿领域专家系统的构造工具,是用C++语言在Windows平台上开发的.本文分析了OBPES骨架系统的可行性,论述了系统的结构及各组成部分的主要功能、系统的工作原理及应用步骤.系统采用面向对象的知识库,知识自学习包括基于解释的学习及神经网络自学习,推理机制封装于知识类之中,通过特性继承和消息传递来实现.OBPES骨架系统的功能齐全、界面十分友好,将会在选矿方面得到实践的检验,并不断完善.  相似文献   

2.
细胞核骨架—核纤层—中间纤维体系的研究   总被引:3,自引:0,他引:3  
  相似文献   

3.
2-D骨架提取算法研究进展   总被引:2,自引:0,他引:2  
关注2-D骨架提取问题,将其算法分为骨架提取的对称轴分析方法、细化方法以及形状分解方法3大类,分别给出了这3类方法的基本思想和发展脉络,希望通过这样的工作为模式识别、可视化和医学图像处理等相关领域的同行提供一个比较系统和清晰的整体算法框架的参考.  相似文献   

4.
通过Hoechst33258和TRITC-Phalloidin对烟草茎表皮薄层培养细胞的非固定染色观察,发现细胞无丝分裂过程中核及其外围微丝鞘发生了很大变化.染色质在分裂时形成卷曲拉裂状,此时核外微丝鞘完全消失.直至染色质分开后,两组染色质由伸张状态回缩时,微丝鞘才重新聚合排列,并最后形成两个子核的微丝鞘.  相似文献   

5.
文章就植物花粉管、保卫细胞中微丝骨架以及微丝骨架与信号转导的一些研究进展作了简要介绍 .  相似文献   

6.
缓释骨架材料研究进展   总被引:1,自引:0,他引:1  
赵红 《科技信息》2008,(33):31-31
骨架型缓释制剂由于制备简便,是应用最广泛的一种剂型。而骨架材料的合理应用是药物达到缓释的一个重要条件。本文主要介绍了乙基纤维素、HPMC的研究情况。  相似文献   

7.
8.
准H-闭骨架     
给出了准H-闭骨架的定义,并证明了:任何一个准H-闭骨架都是H-闭和局部H-闭的;一个非H-闭的骨架的Katetov扩张同构于该骨架的一个单点H-闭扩张的充分必要条件是该骨架为准H-闭骨架.最后,给出了一个非H-闭的准H-闭骨架的例子.  相似文献   

9.
猪卵母细胞体外成熟的研究   总被引:9,自引:0,他引:9  
从屠宰场收集卵巢,用注射器从卵泡中吸出卵丘-卵母细胞复合体,对猪卵母细胞体外成熟的条件进行研究,根据卵母细胞体外成熟时的核成熟率、胞质成熟及体外受精时精子的穿卵速度,合适的体外成熟培养时间为42~45h.卵母细胞周围卵丘细胞的多少及其排列紧密状态与卵母细胞的体外成熟率密切相关。卵泡大小与卵母细胞的体外成熟率有关,大卵泡卵优于小卵泡卵。PMSG促进猪卵母细胞体外成熟。  相似文献   

10.
"两步法"体外培养山羊卵母细胞的初步研究   总被引:4,自引:0,他引:4  
体外成熟培养的卵母细胞经本外受精后,囊胚发育率远低于体内成熟卵母细胞,原因之一是由于体外成熟卵母细胞的不充分获能造成的,有假说认为:卵母细胞在体外培养过程中,如果延长GV期,可促进卵母细胞进一步获能,从而提高发育潜能。本文以山羊卵子为研究对象,探讨了山羊卵泡各种成分以及异种家畜卵泡液对山羊卵母细胞核成熟抑制以及抑制解除后减数分裂的影响,结果显示,山羊50%Q卵泡液、100%卵泡液、半卵泡、打孔整体卵泡以及完整卵泡对山羊卵母细胞的核成熟抑制率分别为:0.00%、9.38%、60.47%、78.26%和70.09%,随后,对经山羊半卵泡、打孔整体卵泡、完整卵泡抑制培养后的卵子进行恢复培养发现,卵子核成熟率分别为:64.29%、3.49%和4.13%,山卵母细胞与半卵泡共培养24h后进行0h、12h、20h、24h和30h的恢复培养,核成率分别为:0.00%、20.00%、61.90%、64.29%和43.75%,表明山羊半卵泡可以有效抑制山羊卵母细胞使之处于GV期,并且这种抑制作用可以恢复,恢复培养时间以20h和24h较为适宜,初步研究异种家畜卵泡液对山羊卵母细胞核成熟抑制的影响发现,50%牛卵泡液、1005牛卵泡液、50%绵羊卵泡液、100%绵羊卵泡液对山羊卵母细胞核成熟抑制率分别为3.7%、21.88%、10.00%、58.82%,表明,100%绵羊卵泡液对山羊卵母细胞核成熟抑制效果较好。  相似文献   

11.
动物卵子膜凝集素受体及其在生殖中的功能   总被引:1,自引:0,他引:1  
凝集素及其受体是一新研究热点 ,卵子膜凝集素受体参与受精过程 .本文从卵子膜凝集素受体的结构分布特点、积累和功能 (精卵识别和结合 ,促有丝分裂 )三方面概述了卵子膜凝集素受体的研究进展 .  相似文献   

12.
用组织学方法对短额负蝗卵子发生和卵母细胞凋亡进行了显微观察.根据卵母细胞的大小、形态、胞核的变化、卵黄物质的形成以及滤泡细胞的形态变化等特征,将短额负蝗卵子发生分为3个时期8个阶段,并描述了各个阶段卵母细胞和滤泡细胞的形态特征.卵子发生过程中卵母细胞凋亡现象主要发生在卵母细胞生长期,特征主要表现为滤泡细胞向卵母细胞质内分裂增殖,卵母细胞的胞质不均匀,出现许多空泡状物质.  相似文献   

13.
The actin cytoskeleton is an important component of eukaryotic cell cytoskeleton and is temporally and spatially controlled by a series of actin binding proteins (ABPs). Among ABPs, formin family proteins have attracted much attention as they can nucleate unbranched actin filament from the profilin bound actin pool in vivo. In recent years, a number of formin family members from different organisms have been reported, and their characteristics are known more clearly, although some questions are still to be clarified. Here, we summarize the structures, func-tions and nucleation mechanisms of different formin family proteins, intending to compare them and give some new clues to the study of formins.  相似文献   

14.
15.
The formation of the polarity of pollen protoplast and the dynamics of actin cytoskeleton were observed by non-fixation, Alexa-Phalloidin probing and confocal laser scanning microscopy. Our results showed that the protoplast obtained from stored pollen contained numerous crystalline fusiform bodies to constitute a storage form of actin. When dormant pollen was hydrated, the actin cytoskeleton forms a fine network spreading uniformly in the protoplast. In the process of polarity formation and germination of pollen protoplast, actin filaments marshaled slowly to the brim, and then formed multilayer continuous actin filament bundles surrounding the cortical of the protoplast. When the protoplast was exposed to actin filament-disrupting drugs, such as Latrunculin A and Cytochalasin D, continuously arranged actin bundles were disturbed and in this condition, the protoplast could not germinate. But when exposed to actin filament stabiling drug-phalliodin, the dynamics of actin filaments in the protoplasts behaved normally and the protoplasts could germinate normally. These results were also confirmed by the pharmacology experiments on pollen grains. And when Latrunculin A or Cytochalasin D was washed off, the ratio of pollen germination was resumed partly. All the results above show that the dynamic organization of the actin cytoskeleton are critical in the cell polarity formation and germination of pollen protoplast, and that the reorganization of actin cytoskeleton is mainly due to the rearrangement of actin filament arrays.  相似文献   

16.
Mitogen-activated protein kinase (MAPK) is a family of Ser/Thr protein kinases expressed widely in eukaryotic cells. MAPK is activated by a cascade of protein kinase phosphorylation and plays pivotal roles in regulating meiosis process in oocytes. As an important physical substrate of MAPK, p90rsk mediates numerous MAPK functions. MAPK was activated at G2/M transition during meiosis. Its activity reached the peak at MⅠ stage and maintained at this level until the time before the pronuclear formation after fertilization. There is complex interplay between MAPK and MPF in the meiosis regulation. Furthermore, other intracellular signal transducers, such as cAMP, protein kinase C and protein phosphotase, ect., also regulated the activity of MAPK at different stages during meiosis in oocytes. In the present article, the roles of MAPK signaling pathway in oocyte meiosis are reviewed and discussed.  相似文献   

17.
Protein kinase C (PKC) is a superfamily of Ser/Thr protein kinases that is distributed widely in eukaryotes. It plays key regulatory roles at multiple steps of oocyte meiotic maturation and fertilization. During the process of meiotic maturation, the activation of PKC in cumulus cells stimulates meiotic maturation, whereas the activation of PKC in oocytes results in the inhibition of germinal vesicle breakdown. PKC activity increases following the meiotic maturation, and decreases at the transition of metaphase/anaphase in meiosis I, so as to facilitate the release of the first polar body and the entry of meiosis II. In fertilization of mammalian oocytes, PKC may act as one of the downstream targets of Ca2+ to stimulate the cortical granule exocytosis, release the oocytes from MII arrest and to induce pronucleus formation. PKC is also involved in the regulation of maturation promoting factor (MPF) and mitogen-activated protein kinase (MAPK). Several PKC isoforms have been identified in mammalian oocytes, and there is evidence showing that classical PKCs may be the principal mediator of oocyte cortical reaction.  相似文献   

18.
研究在成熟液中添加表皮生长因子(Epidermal growth factor,EGF)以及成熟时间对牦牛卵母细胞体外成熟及孤雌胚胎体外发育的影响,以确立牦牛卵母细胞体外成熟的最佳体系.结果表明,成熟液中添加EGF组的成熟率明显高于未添加组(P<0.05),并且牦牛卵母细胞的成熟率随着EGF添加的浓度增加也不断上升;随着体外培养时间的延长,成熟率逐渐增加,培养24 h后成熟率趋于稳定;胚胎体外培养液中添加EGF能显著提高孤雌胚胎的8-细胞和囊胚形成率(P<0.05).由此推测:在体外培养22-24 h,且添加40 μg/mL EGF最有利于牦牛卵母细胞体外成熟;胚胎培养液中添加40μg/mLEGF能显著提高牦牛孤雌胚胎的体外发育能力.  相似文献   

19.
NO (nitric oxide), known as a key signal molecule in plant, plays important roles in regulation of stomatal movement. In this study, microtubule dynamics and its possible mechanism in the NO signal pathway were investigated. The results were as follows: (i) In vivo stomatal aperture assays revealed that both vinblastine (microtubule-disrupting drug) and SNP (exogenous NO donor) prevented stomatal opening in the light, and vinblastine even could enhance the inhibitory effect of SNP, whereas taxol (a microtubule-stabilizing agent) was able to reduce this effect; (ii) microtubules in the opening Arabi- dopsis guard cells expressing GFP:α-tubulin-6 (AtGFP:α-tubulin-6) were organized in parallel, straight and dense bundles, radiating from the ventral side to the dorsal side, and most of them were localized perpendicularly to the ventral wall; (iii) under the same environmental conditions, treated with SNP for 30 min, the radial arrays of microtubules in guard cells began to break down, twisted partially and be- came oblique or exhibited a random pattern; (iv) furthermore, the involvement of cytosolic Ca2 in this event was tested. Stomatal aperture assays revealed that BAPTA-AM (a chelator of Ca2 ) greatly sup- pressed the effect of NO on stomatal closure; however, it did not show the same function on stomatal closure induced by vinblastine. When BAPTA-AM was added to the SNP-pretreated solution, the SNP-induced disordered microtubulue cytoskeleton in guard cells underwent rearrangement in a time-dependent manner. After 30 min of treatment with BAPTA-AM, the cortical microtubules resumed the original radial distribution, almost the same as the control. All this indicates that NO may promote rearrangement of microtubule cytoskeleton via elevation of [Ca2 ]cyt (free Ca2 concentration in the cy- toplasm), finally leading to stomatal closure.  相似文献   

20.
The SR-protein kinase activity was analyzed and the cytological changes were observed during oocyte maturation in bisexual transparent color crucian carp ( Carassius auratus color variety). The results revealed that the SR-protein kinase activity was sensitive to the artificially induced spawning hormones, and the change of oscillatory activity was similar to that of the maturation-promoting factor (MPF) kinase that regulates meiotic cell cycle in fish.  相似文献   

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