新时期数字图书馆特征与建设

论述了数字图书馆的特征,探讨了建设数字图书馆中应注意的问题,包括版权问题、原创性问题、队伍建设问题、环境优化问题、数字信息资源建设问题等。     

中国风险投资的特点、存在的问题及对策研究

本文分析了我国风险投资业的基本特点,阐述了中国风险投资存在的主要问题,即投资主体问题、退出机制问题、人才问题、法制环境问题、项目源问题,并针对这些问题提出了一系列对策,同时就各项对策具体提出了一些可操作性的建议。     

《企业会计制度》实施中的资产问题及建议

就《企业会计制度》实施过程中存在的资产问题,如坏账准备问题、存货问题、投资问题、固定资产问题、无形资产问题等进行了深入的探讨,并提出了相关的建议。     

大学生主要心理健康问题及对策探讨

近年,大学生心理健康问题受到越来越多的关注,笔者从学业问题、人际关系问题、情绪问题、就业问题四个方面详细分析了目前大学生面临的主要心理健康问题,并从宏观上提出了解决这些问题的相应对策.     

英语教师问题意识的培养

作为英语教师在英语教学中要注重问题意识的培养。在报刊网络问题征答中,树立问题意识;在日常教学实践中,捕捉小问题,进一步引发对自己教学行为的深度思考,逐渐增强自己的科研意识、方法意识、问题意识;在学校教研活动中,提炼“真”问题,通过专题教研发挥教师群体的作用,解决教学实践中所遇到的问题,使教师在不断提出问题、解决问题的过程中实现自己的专业发展;开展问卷调查,激发老师的问题意识,改善和提升教学水平,唤醒教师的问题意识,倡导教师带着问题去学习、去教学、去反思、去总结、去研究、去完善、去提升。     

关于“顶层设计”的思考

从"顶层设计"要坚持的四项原则出发,重点阐述了"顶层设计"必须解决的八大问题,即土地制度问题、经济结构问题、财政改革问题、城镇化问题、资源价格问题、金融体制问题、创新机制问题及国企改革与国退民进问题。"顶层设计"不能停留于学者专家的言谈、思想和文章,不能停留于官方的口号式文体。为此,提出从设计到落实过程的保障措施。     

充分利用网络平台促进中职生心理健康教育

针对中职生自制能力弱的现状,利用现代网络资源加强对职校生进行心理健康教育,以解决中职生的学习心理问题、情感心理问题、个性心理问题、自我心理问题、人性心理问题、性心理问题和择业心理问题的困惑等等,探讨网络心理健康教育优势,提倡建立网上教育平台。     

大学新生适应性问题的探讨与德育对策

“大学新生入学适应性问题”是一个普遍性的问题,几乎每位大学新生都会碰到,只不过在不同学生身上侧重点有所不同,有的突出表现为生活能力问题、有的是情感依赖问题、有的是经济问题、有的是学习问题、还有人际关系问题、专业思想问题等等。对于这些问题,学生、学生家长和高校教师都颇为关注,都希望能够寻找到一条有效的途径来尽快解决,使他们能早日融入大学生活,顺利完成学业。     

数字电路实验常见故障的分析与排除

分析了数字电路实验中常见故障的产生原因与排除方法,包括电路设计问题、电源问题、布线问题、仪表使用问题、电源耦合问题等。     

学生无问题成因及对策初探

我们现在的学生普遍缺乏问题意识,缺乏一种发现问题,提出问题,解决问题的意识,笔者就数学学习中的问题意识从以下四方面进行了初步探究：一、目前的现状和研究情况,二、培养学生问题意识的方法与措施,三、如何引导学生自己提出问题,四、教给学生发现问题的方法。     

维生素E琥珀酸酯诱导肿瘤细胞凋亡作用机制的研究进展

维生素E琥珀酸酯是维生素E的衍生物。维生素E琥珀酸酯对肿瘤细胞有显著的凋亡杀伤作用,而对正常细胞没有明显的毒性反应。维生素E琥珀酸酯诱导肿瘤细胞凋亡的机制主要有线粒体途径、脂肪酸合成酶信号系统、MAPK途径、蛋白激酶C等途径。这些机制的研究发现可以为开发出新型与VES抗肿瘤作用同一靶分子的抗肿瘤药物开辟新途径。     

都支杜鹃和黄山杜鹃叶片结构的观察

都支杜鹃和黄山杜鹃叶片的构造,除具有上表皮的角质层较厚并有瘤状突起、有下皮层、叶肉无细胞间隙、栅栏组织细胞多层、机械组织发达等特点外,发现在叶肉的海绵组织中有大量大型的贮水细胞。干旱时贮水细胞失水,引起叶片向下反卷运动,以减少水分的蒸腾,此种适应现象在双子叶植物中极为罕见。     

白喉毒素及其编码基因TOX在分子生物学中的应用

对白喉毒素及其编码基因的结构及其作用原理进行了详细说明,并对它们在分子生物学中的运用作了概要的介绍。     

肝细胞凋亡的基因调控

细胞凋亡是生物界普遍存在的一种基本生理活动,大量研究表明,细胞凋亡过程与许多细胞因子及基因密切相关。本文综述了与肝细胞凋亡有关的p53基因、C-myc基因、Fas基因、Bax基因和Bcl-2基因等。     

Exploring genome space

The completion of entire genome sequences of many experimental organisms, and the promise that the human genome will be completed in the next year, find biology suddenly awash in genome-based data. Scientists are scrambling to develop new technologies that exploit genome data to ask entirely new kinds of questions about the complex nature of living cells.     

A maternally inherited superantigen encoded by a mammary tumour virus.

A collection of superantigens, molecules which in combination with class II major histocompatibility complex (MHC) engage T cells bearing particular V beta chains as part of their alpha beta receptors, have recently been described. The mouse self superantigen, Mls-1a, for example, in conjunction with many MHC class II proteins, engages mouse T cells bearing V beta 6, 7, 8.1 and 9, almost regardless of the sequences of the other variable components of the receptors on the T cells. Two types of superantigen have been identified so far: first, superantigens encoded in the mouse genome, such as Mls-1a; second, superantigens produced by bacteria, such as the staphylococcal enterotoxins. Although the latter type of superantigens are in many cases known to be proteins of about 220 amino acids, nothing is known about the structures of any of the superantigens encoded in mouse. Here we describe the properties of a new mouse superantigen. The antigen is maternally transmitted in milk and is probably encoded by a mammary tumour virus (MTV). Given the known genetic linkage between at least one of the mouse genomic superantigens and endogenous MTV integration sites, it is tempting to speculate that the superantigen described here and some of the endogenous mouse superantigens are encoded by MTVs.     

Characteristics of C4 photosynthesis in stems and petioles of C3 flowering plants.

Most plants are known as C3 plants because the first product of photosynthetic CO2 fixation is a three-carbon compound. C4 plants, which use an alternative pathway in which the first product is a four-carbon compound, have evolved independently many times and are found in at least 18 families. In addition to differences in their biochemistry, photosynthetic organs of C4 plants show alterations in their anatomy and ultrastructure. Little is known about whether the biochemical or anatomical characteristics of C4 photosynthesis evolved first. Here we report that tobacco, a typical C3 plant, shows characteristics of C4 photosynthesis in cells of stems and petioles that surround the xylem and phloem, and that these cells are supplied with carbon for photosynthesis from the vascular system and not from stomata. These photosynthetic cells possess high activities of enzymes characteristic of C4 photosynthesis, which allow the decarboxylation of four-carbon organic acids from the xylem and phloem, thus releasing CO2 for photosynthesis. These biochemical characteristics of C4 photosynthesis in cells around the vascular bundles of stems of C3 plants might explain why C4 photosynthesis has evolved independently many times.     

谈印象整饰在构建和谐师生关系中的应用

社会的和谐,国家的和谐是由很多和谐的细胞构成的,师生关系的和谐是其中的一分子。同时,和谐师生关系的建立是学校及社会实现教育教学目标的重要条件。教师可以通过进行合适的印象整饰,使学生对自己形成和保留良好印象,以促进和谐师生关系的建立。     

Variability and memory of protein levels in human cells

Protein expression is a stochastic process that leads to phenotypic variation among cells. The cell-cell distribution of protein levels in microorganisms has been well characterized but little is known about such variability in human cells. Here, we studied the variability of protein levels in human cells, as well as the temporal dynamics of this variability, and addressed whether cells with higher than average protein levels eventually have lower than average levels, and if so, over what timescale does this mixing occur. We measured fluctuations over time in the levels of 20 endogenous proteins in living human cells, tagged by the gene for yellow fluorescent protein at their chromosomal loci. We found variability with a standard deviation that ranged, for different proteins, from about 15% to 30% of the mean. Mixing between high and low levels occurred for all proteins, but the mixing time was longer than two cell generations (more than 40 h) for many proteins. We also tagged pairs of proteins with two colours, and found that the levels of proteins in the same biological pathway were far more correlated than those of proteins in different pathways. The persistent memory for protein levels that we found might underlie individuality in cell behaviour and could set a timescale needed for signals to affect fully every member of a cell population.     

Cell lineage analysis reveals multipotency of some avian neural crest cells

A major question in developmental biology is how precursor cells give rise to diverse sets of differentiated cell types. In most systems, it remains unclear whether the precursors can form many or all cell types (multipotent or totipotent), or only a single cell type (predetermined). The question of cell lineage is central to the neural crest because it gives rise to numerous and diverse derivatives including peripheral neurons, glial and Schwann cells, pigment cells, and cartilage. Although the sets of derivatives arising from different populations of neural crest cells have been well-documented, relatively little is known about the developmental potentials of individual neural crest cells. We have iontophoretically microinjected the vital dye, lysinated rhodamine dextran (LRD) into individual dorsal neural tube cells to mark unambiguously their descendants. Many of the resulting labelled clones consisted of multiple cell types, as judged by both their location and morphology. Cells as diverse as sensory neurons, presumptive pigment cells, ganglionic supportive cells, adrenomedullary cells and neural tube cells were found within individual clones. Our results indicate that at least some neural crest cells are multipotent before their departure from the neural tube.