Regulation of BMP4 on the proliferation and differentiation in SVZa neural stem cells

The neural stem cells in the anterior subventricular zone (SVZa) mainly generate the progenitors that will differentiate into neurons, and along a highly circumscribed migratory access Rostral migratory stream (RMS), they migrate to the olfactory bulbs (OB). To understand the effects of BMPs on SVZa neural stem cells, in this study BMP4 at various concentrations was used to induce SVZa neural stem cells, and the living cell labeling using BMP4 promotor conjugated with red fluorescence protein showed the expression of BMP4 dynamically. The results demonstrated that low BMP4 doses (1-5 ng/mL) promoted while high doses (10-100 ng/mL) inhibited the proliferation of SVZa neural stem cells, and BMP4 promotedneuron differentiation in the early stage (1-3 d), howeverm, it inhibited the neuron commitment after 4 d. Noggin, the antagonist of BMP4, blocked the physiological effects of BMP4. In OB, BMP4 is mainly to accelerate the progenitors to withdraw from the cell cycle and trigger the differentiation, and in RMS, it promotes the proliferation of committed progenitors and not differentiation, further in SVZa, BMP4 enhances astrocyte commitment.     

Synthesis and crystal structure of the trimetallic erbium tetrahydride complex [Li(THF)4][{(ButCp)2Er(μ-H)} 3-(μ3-H)]

Reaction of [(Bu′tCp)2Er(μ-CI)]2 with Bu′Li in 1:1 molar ratio in THF at -78℃, after work-up, afforded the trimetallic erbium tetrahydride complex [Li(THF)4][{(Bu′Cp)2Er(μ-H)}3(μ3-H)] (1) by β-hydrogen elimination reaction. Crystal structure determination reveals that complex 1 has discrete ion pair structure. The anion is composed of three (Bu′Cp)2Er units to form a triangle array connected by three bridged hydrogen atoms, and the fourth hydrogen atom coordinated to three Er^3 ions. The coordination num-ber for each Er^3 ion is 9.     

《服装结构设计》网络教学课件系统的研发

为适应服装专业远程教育的需要,针对《服装结构设计》课程,通过对多媒体教学系统的研究,利用网页设计工具,开发了基于Web的《服装结构设计》网络课件系统。     

The refinement algorithm consideration in text clustering scheme based on multilevel graph

To construct a high efficient text clustering algorithm, the multilevel graph model and the refinement algorithm used in the uncoarsening phase is discussed, The model is applied to text clustering. The performance of clustering algorithm has to be improved with the refinement algorithm application, The experiment result demonstrated that the muhilevel graph text clustering algorithm is available,     

Circle quorum system-based non-stop network service model

Rapid developments in network systems of business service have resulted in more reliance on distributed computing, typified by “subscriber/push” architectures. Unfortunately, frequent and unexpectable network failures were routine, and downtime was not in hours, but in days. High availability has become the most important factor decreasing business risk and improving Quality of Service. Cluster technology has solved the non-stop problem on Local Area Network. However, most technologies including cluster today fail to ensure the non-stop Internet service based on Routers. With good performance on high availability and fault tolerance, quorum systems are very suitable for application to distributed business service networks. In this work, we modeled and developed a non-stop Internet service system based on a new quorum system, circle quorum system, for Boston Mutual Fund Broker, US. With five protocols, it provided highly available data services for clients on Internet.     

A high-resolution map of human chromosome 12

Our sequence-tagged site-content map of chromosome 12 is now integrated with the whole-genome fingerprinting effort. It provides accurate and nearly complete bacterial clone coverage of chromosome 12. We propose that this integrated mapping protocol serves as a model for constructing physical maps for entire genomes.     

High critical current density and enhanced irreversibility field in superconducting MgB2 thin films

The discovery of superconductivity at 39 K in magnesium diboride offers the possibility of a new class of low-cost, high-performance superconducting materials for magnets and electronic applications. This compound has twice the transition temperature of Nb3Sn and four times that of Nb-Ti alloy, and the vital prerequisite of strongly linked current flow has already been demonstrated. One possible drawback, however, is that the magnetic field at which superconductivity is destroyed is modest. Furthermore, the field which limits the range of practical applications-the irreversibility field H*(T)-is approximately 7 T at liquid helium temperature (4.2 K), significantly lower than about 10 T for Nb-Ti (ref. 6) and approximately 20 T for Nb3Sn (ref. 7). Here we show that MgB2 thin films that are alloyed with oxygen can exhibit a much steeper temperature dependence of H*(T) than is observed in bulk materials, yielding an H* value at 4.2 K greater than 14 T. In addition, very high critical current densities at 4.2 K are achieved: 1 MA cm-2 at 1 T and 105 A cm-2 at 10 T. These results demonstrate that MgB2 has potential for high-field superconducting applications.     

Artistic Features of “Love is a Fallacy”

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High-Q photonic nanocavity in a two-dimensional photonic crystal

Photonic cavities that strongly confine light are finding applications in many areas of physics and engineering, including coherent electron-photon interactions, ultra-small filters, low-threshold lasers, photonic chips, nonlinear optics and quantum information processing. Critical for these applications is the realization of a cavity with both high quality factor, Q, and small modal volume, V. The ratio Q/V determines the strength of the various cavity interactions, and an ultra-small cavity enables large-scale integration and single-mode operation for a broad range of wavelengths. However, a high-Q cavity of optical wavelength size is difficult to fabricate, as radiation loss increases in inverse proportion to cavity size. With the exception of a few recent theoretical studies, definitive theories and experiments for creating high-Q nanocavities have not been extensively investigated. Here we use a silicon-based two-dimensional photonic-crystal slab to fabricate a nanocavity with Q = 45,000 and V = 7.0 x 10(-14) cm3; the value of Q/V is 10-100 times larger than in previous studies. Underlying this development is the realization that light should be confined gently in order to be confined strongly. Integration with other photonic elements is straightforward, and a large free spectral range of 100 nm has been demonstrated.     

高丰度硅-28同位素的分离技术

同位素纯硅片具有特殊的物理性质,在信息技术领域有着非常广阔的应用前景。为获得高丰度28Si,利用国产的高速气体离心机,选择SiF4作为分离的工作介质,对硅同位素进行了离心分离实验。通过单机分离实验,调整气体离心机的有关参数,摸索出适合级联分离的单机参数,同时得到气体离心机分离硅同位素的单位质量数的全分离系数γ0。利用由4台离心机组成的级联,经过6个阶段的分离,得到了28Si丰度达到99.5%的样品。实验结果表明,离心法分离硅同位素是完全可行的。