Zebrafish miR-214 modulates Hedgehog signaling to specify muscle cell fate

Numerous microRNAs (miRNAs) have been discovered in the genomes of higher eukaryotes, and functional studies indicate that they are important during development. However, little is known concerning the function of individual miRNAs. We approached this problem in zebrafish by combining identification of miRNA expression, functional analyses and experimental validation of potential targets. We show that miR-214 is expressed during early segmentation stages in somites and that varying its expression alters the expression of genes regulated by Hedgehog signaling. Inhibition of miR-214 results in a reduction or loss of slow-muscle cell types. We show that su(fu) mRNA, encoding a negative regulator of Hedgehog signaling, is targeted by miR-214. Through regulation of su(fu), miR-214 enables precise specification of muscle cell types by sharpening cellular responses to Hedgehog.     

我国廉租房建设中存在的问题及对策分析

廉租房作为解决城镇低收入家庭住房问题的一种主要渠道,其建设的进展情况并不乐观,在建设模式、资金供应、分配标准等方面仍存在不少问题。为此,需要加强认识、采取多元化融资方式、完善廉租房相关制度,使廉租房建设真正落实到位,从而促进我国住房保障体系乃至整个房地产市场的健康发展。     

An Empirical Study of Effects of Chinese Government＇s Tax Revenue and Expenditure on Its GDP＇s Growth

Public spending is a major policy tool for the government to adjust the macro economic progress. This paper characterizes the effects of shocks in government spending and taxes on Chinese economy growth since 1978. It does so by using a mixed structural VAR （SVAR） approach. Identification is achieved by using institutional information about the tax and spending to identify automatic and discretionary response, and by implication, to infer fiscal shocks. The results show positive government spending shocks as having a positive effect on output, and positive tax shocks as having a negative effects.     

An efficient algorithm to generate candidates in discovering frequent episodes

0 IntroductionData mining is widely used in many research fieldssuch as decision supporting systems[1], bio-informationanalysis[2]and knowledge engineering[3-5]. Most data col-lected from scientific experiments or telecommunicationnetworks have inherent sequential nature inthemand canthus be abstractly viewed as a sequence of events . Onebasic problemin miningsuchevent sequencesis discoveryof recurrent combinations of events , which are calledepisodes. Once frequent episodes are discovered,rul…     

关于新时期实验物理教学的几点思考

本文结合我校实际，对新时期实验物理教学中出现的一些问题和现象作了分析讨论。提出相应的措施和方法。     

Finding finer functions for partially characterized proteins by protein-protein interaction networks

Based on high-throughput data, numerous algorithms have been designed to find functions of novel proteins. However, the effectiveness of such algorithms is currently limited by some fundamental factors, including (1) the low a-priori probability of novel proteins participating in a detailed function; (2) the huge false data present in high-throughput datasets; (3) the incomplete data coverage of functional classes; (4) the abundant but heterogeneous negative samples for training the algorithms; and (5) the lack of detailed functional knowledge for training algorithms. Here, for partially characterized proteins, we suggest an approach to finding their finer functions based on protein interaction sub-networks or gene expression patterns, defined in function-specific subspaces. The proposed approach can lessen the above-mentioned problems by properly defining the prediction range and functionally filtering the noisy data, and thus can efficiently find proteins’ novel functions. For thousands of yeast and human proteins partially characterized, it is able to reliably find their finer functions (e.g., the translational functions) with more than 90% precision. The predicted finer functions are highly valuable both for guiding the follow-up wet-lab validation and for providing the necessary data for training algorithms to learn other proteins.     

Identification of the Angel -related elements in cyprinid fishes and their phylogenetic implications

Angel-related element belongs to the family of miniature inverted-repeat transposable elements (MITEs). In this paper we report the identification of an Angel- related element in the series Leuciscini of cyprinid fishes, which is located in the second intron of the growth hormone (GH) gene. We have also found that this element is absent in orthologous locus in the series Barbini of cyprinid fishes, that provides new evidence for the monophyly of the series Leuciscini. The insertion of Angel -related element into the GH gene might take place in the common ancestor of the series Leuciscini after its divergence from the series Barbini. The high sequence divergence and relatively broad species distribution of Angel-related elements implies that they might be ancient transposons which appeared about 26 million years ago.     

试论魏晋“深情”及其诗学意义

魏晋时期,伴随着理性世界的转变,人们的感性世界也发生了极大的变化,出现所谓的魏晋“深情”。这种以知识分子为情感主体的“深情”,既不同于《诗经》时代原发性的“民情”,也不同于儒家“发乎情,止乎礼义”的“性情”和道家“有人之形而无人之情”的“天情”,它是知识分子个体生命意识觉醒之后于天地宇宙中寻求心灵安顿和精神自由的情感,即人生和宇宙合而为一的生命超越之情。正是这种魏晋“深情”,把中国诗学引向强调“神与物游”和“情景相生”的抒情道路,并深深地刻上了宇宙情怀。     

Design and passive analysis of a novel softness display device

Simulating the softness property of object is quite a challenge in virtual reality system. A novel softness display system was developed based on the principle of deformable length of elastic element control （DLEEC）. In the system, the equivalent stiffness of the device is adjustable, and is inversely proportional to the third power of the deformable length of elastic beam. PD position control is employed to guarantee the accurate softness display. The softness of the virtual objects in large scale can be felt with the softness display device. Compared with other haptic devices, the device is passive and exert the react force only when the operator ＂actively touch＂ the virtual objects. The stability of the softness display system was analyzed. It was theoretical proved that the system satisfied the criteria of wide impedance range ＂Z-width＂, and the performance was superior to an active system. The experimental results were presented.     

核磁共振跟踪反应法研究5—O—乙酰基—2.3-双脱氧-D.L-呋喃戊糖基氯的合成

以乙酸四氢呋喃甲酯为原料,通过自由基氯化反应,合成双脱氧核苷类抗艾滋病药物的重要中间体化合物5—0—乙酰基—2.3—双脱氧—D.L—吹喃戊糖基氯.对于此种不稳定的中间体化合物,用~1HNMR跟踪监测反应物的方法,研究了改变反应时间、反应温度和反应物摩尔比对反应产物的影响,获得了最佳的反应条件,使其收率从10％提高到50％左右.