以幸福观为切入点改进高校思想政治教育工作

幸福观培养是高校思想政治教育的重要内容之一,对于大学生成长、成才具有重要的意义。以大学生的幸福观为视角,深入剖析当前大学生中存在的幸福观问题,进一步分析破解"幸福观问题"的必要性和急迫性,提出以幸福观为切入点增添高校思想政治教育生活色彩的有效措施,切实增强高校思想政治工作的实效性。     

NIH guidelines. Researchers get green light for work on stem cells

The National Institutes of Health (NIH) issued final guidelines last week allowing NIH-funded researchers to derive human pluripotent stem cells from fetal tissue, but not from embryos. Scientists may also work with embryonic stem cells, but may obtain them only from private sources and must ensure that derivation meets certain ethical conditions. The NIH spent nearly a year finalizing the guidelines, which researchers hope will allow work leading to the improved treatment of diabetes, Parkinson's, and other diseases.     

Oligodendrocyte precursor cells reprogrammed to become multipotential CNS stem cells

During animal development, cells become progressively more restricted in the cell types to which they can give rise. In the central nervous system (CNS), for example, multipotential stem cells produce various kinds of specified precursors that divide a limited number of times before they terminally differentiate into either neurons or glial cells. We show here that certain extracellular signals can induce oligodendrocyte precursor cells to revert to multipotential neural stem cells, which can self-renew and give rise to neurons and astrocytes, as well as to oligodendrocytes. Thus, these precursor cells have greater developmental potential than previously thought.     

Male germline stem cells: from mice to men

The production of functional male gametes is dependent on the continuous activity of germline stem cells. The availability of a transplantation assay system to unequivocally identify male germline stem cells has allowed their in vitro culture, cryopreservation, and genetic modification. Moreover, the system has enabled the identification of conditions and factors involved in stem cell self-renewal, the foundation of spermatogenesis, and the production of spermatozoa. The increased knowledge about these cells is also of great potential practical value, for example, for the possible cryopreservation of stem cells from boys undergoing treatment for cancer to safeguard their germ line.     

Mammalian neural stem cells

Neural stem cells exist not only in the developing mammalian nervous system but also in the adult nervous system of all mammalian organisms, including humans. Neural stem cells can also be derived from more primitive embryonic stem cells. The location of the adult stem cells and the brain regions to which their progeny migrate in order to differentiate remain unresolved, although the number of viable locations is limited in the adult. The mechanisms that regulate endogenous stem cells are poorly understood. Potential uses of stem cells in repair include transplantation to repair missing cells and the activation of endogenous cells to provide "self-repair. " Before the full potential of neural stem cells can be realized, we need to learn what controls their proliferation, as well as the various pathways of differentiation available to their daughter cells.     

Differentiation of embryonic stem cells to insulin-secreting structures similar to pancreatic islets

Although the source of embryonic stem (ES) cells presents ethical concerns, their use may lead to many clinical benefits if differentiated cell types can be derived from them and used to assemble functional organs. In pancreas, insulin is produced and secreted by specialized structures, islets of Langerhans. Diabetes, which affects 16 million people in the United States, results from abnormal function of pancreatic islets. We have generated cells expressing insulin and other pancreatic endocrine hormones from mouse ES cells. The cells self-assemble to form three-dimensional clusters similar in topology to normal pancreatic islets where pancreatic cell types are in close association with neurons. Glucose triggers insulin release from these cell clusters by mechanisms similar to those employed in vivo. When injected into diabetic mice, the insulin-producing cells undergo rapid vascularization and maintain a clustered, islet-like organization.     

合理规划布局巧设园林空间

园林空间是一种艺术空间,是园林设计的关键。而设计手法是空间布置、平面构图、合理造园的重要手段。介绍了南海桂城平洲广场的设计构思,阐明了现代园林规划中的设计手法与空间布局技巧。     

成体干细胞的可塑性

传统观念认为,成体干细胞只能分化成其自身来源组织的细胞类型。但近年大量的研究表明,成体干细胞可跨系甚至跨胚层分化成在发育上与之无关的其他组织的细胞类型,即具有可塑性。文章对成体干细胞可塑性的研究结果、分化机制、应用前景及需解决的问题等进行了综述。