15个籼稻杂交组合不同生育时期光合能力研究

对15个水稻组合剑叶在齐穗期和成熟期的光合作用以及茎鞘物质的输出率和转换率进行了研究,结果表明,15个组合中冈46 A/绵恢725和绵5A/辐恢838的特殊配合力最好,冈46 A/科恢746和绵香5A/明恢63的特殊配合力相对较差。     

Science Letters:Brain metastases of melanoma-mechanisms of attack on their defence system by engineered stem cells in the microenvironment

This report gives a better emphasis on the role of targeted effectors (e.g. a combination of 5-FC with CD-NSPCs as compared to the application of NSPCs alone) and how such delivery of pro-drug activating enzymes and other tumor-killing substances may overcome melanocytic defence system, interact with and promote the host defence and immune response modulations not only in melanoma but, potentially, in other highly-metastatic cancers.     

白木香茎次生木质部结构的研究

利用光学显微镜和扫描电镜技术，对白木香茎次生木质部结构进行了解剖研究．结果表明，茎材横切面为散孔材，生长轮不明显，导管分子单穿孔板，木材分子非叠生，绝大多数射线为异形Ⅲ型管孔排列方式多为茎向复管孔或管孔团，具有内函韧皮部．还从解剖学的角度对白木香次生木质部的构造特点进行了讨论．     

Induced pluripotent stem cells: origins, applications, and future perspectives

Embryonic stem(ES)cells are widely used for different purposes,including gene targeting,cell therapy,tissue repair,organ regeneration,and so on.However,studies and applications of ES cells are hindered by ethical issues regarding cell sources.To circumvent ethical disputes,great efforts have been taken to generate ES cell-like cells,which are not derived from the inner cell mass of blastocyst-stage embryos.In 2006,Yamanaka et al.first reprogrammed mouse embryonic fibroblasts into ES cell-like cells called induced pluripotent stem(iPS)cells.About one year later,Yamanaka et al.and Thomson et al.independently reprogrammed human somatic cells into iPS cells.Since the first generation of iPS cells,they have now been derived from quite a few different kinds of cell types.In particular,the use of peripheral blood facilitates research on iPS cells because of safety,easy availability,and plenty of cell sources.Now iPS cells have been used for cell therapy,disease modeling,and drug discovery.In this review,we describe the generations,applications,potential issues,and future perspectives of iPS cells.     

An Aesthetic for Deliberating Online: Thinking Through “Universal Pragmatics” and “Dialogism” with Reference to Wikipedia

In this article we examine contributions to Wikipedia through the prism of two divergent critical theorists: Jürgen Habermas and Mikhail Bakhtin. We show that, in slightly dissimilar ways, these theorists came to consider an “aesthetic for democracy” (Hirschkop 1999) or template for deliberative relationships that privileges relatively free and unconstrained dialogue to which every speaker has equal access and without authoritative closure. We employ Habermas's theory of “universal pragmatics” and Bakhtin's “dialogism” for analyses of contributions on Wikipedia for its entry on stem cells and transhumanism and show that the decision to embrace either unified or pluralistic forms of deliberation is an empirical matter to be judged in sociohistorical context, as opposed to what normative theories insist on. We conclude by stressing the need to be attuned to the complexity and ambiguity of deliberative relations online.     

Progress in Safe Induced Pluripotent Stem Cells for Clinical Applications

诱导性多能干细胞（induced pluripotent stem cells,iPSCs）是被重新编程的、具有多能性的成体细胞。最近的研究证实,iPSCs能够达到与胚胎干细胞同样的全能性。源于成体的iPSCs对药物或毒性筛选、医疗研究以及疾病专一性治疗提供了极其有价值的细胞来源,然而,在应用于临床之前,必须克服潜在的风险,包括iPSCs诱导中病毒的整合、基因的改变。iPSCs潜在的风险涉及外源因子的转入、目标细胞的改变及诱导因子的表达和重新激活等。本文回顾iPSCs的应用前景和面临的挑战,同时对诱导安全性iPSCs的方法进行了讨论。     

Osteogenic differentiation of mesenchymal stem cells promoted by overexpression of connective tissue growth factor

Objective: Large segmental bone defect repair remains a clinical and scientific challenge with increasing interest focusing on combining gene transfection with tissue engineering techniques. The aim of this study is to investigate the effect of connective tissue growth factor (CTGF) on the proliferation and osteogenic differentiation of the bone marrow mesenchymal stem cells (MSCs). Methods: A CTGF-expressing plasmid (pCTGF) was constructed and transfected into MSCs. Then expressions of bone morphogenesis-related genes, proliferation rate, alkaline phosphatase activity, and mineralization were examined to evaluate the osteogenic potential of the CTGF gene-modified MSCs. Results: Overexpression of CTGF was confirmed in pCTGF-MSCs. pCTGF transfection significantly enhanced the proliferation rates of pCTGF-MSCs (P<0.05). CTGF induced a 7.5-fold increase in cell migration over control (P<0.05). pCTGF transfection enhanced the expression of bone matrix proteins, such as bone sialo-protein, osteocalcin, and collagen type I in MSCs. The levels of alkaline phosphatase (ALP) activities of pCTGF-MSCs at the 1st and 2nd weeks were 4.0- and 3.0-fold higher than those of MSCs cultured in OS-medium, significantly higher than those of mock-MSCs and normal control MSCs (P<0.05). Overexpression of CTGF in MSCs enhanced the capability to form mineralized nodules. Conclusion: Overexpression of CTGF could improve the osteogenic differentiation ability of MSCs, and the CTGF gene-modified MSCs are potential as novel cell resources of bone tissue engineering.     

Effect of CO2 enrichment on the glucosinolate contents under different nitrogen levels in bolting stem of Chinese kale (Brassica alboglabra L.)

The effects of CO₂ enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassica alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO₂ concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO₂ concentration, N concentration, and CO₂×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO₂. However, at 20 mmol N/L, elevated CO₂ had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO₂ concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO₂ concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO₂ condition. Project (No. 2007CB109305) supported by the National Basic Research Program (973) of China     

小麦茎杆抗倒伏的模型分析

对小麦茎秆进行受力分析,运用挠曲线近似方程的叠加,势能驻值原理,建立了茎秆在穗重和风载双重作用下茎秆抗倒伏的精确模型,并给出临界风力的具体表达式.结果表明：茎秆的高度越高,承载的临界力越小,但并不是简单的反比例关系;抗弯刚度与倒伏临界力成显著的正线性相关;单穗重的增加也会降低抗倒伏临界力.     

菜用甘薯茎尖不同储存期 Vc 和亚硝酸盐含量的变化研究

利用菜用甘薯茎尖,通过测定其不同贮藏期 Vc 和亚硝酸盐含量,研究了甘薯茎尖在冷藏和冷冻下Vc 及亚硝酸盐含量变化的规律。结果表明：随着贮藏时间的延长,在冷藏和冷冻两种贮藏方式下,甘薯茎尖 Vc 均下降,但冷藏处理较冷冻处理下降幅度小。亚硝酸盐含量出现消长变化,冷冻比冷藏条件贮存亚硝酸盐增加低些。所以食用时应根据需要综合考虑采用冷藏或冷冻,最大限度地降低其不利因素。