鲢鱼早期发育阶段核组蛋白的比较研究

用15％聚丙烯酰胺凝胶电泳分析比较了鲢鱼早期发育的四个重要阶段:原肠后期、心跳期、出膜期幼鱼和眼色素出现期幼鱼的细胞核组蛋白。这四个时期细胞的核心组蛋白(H_4、H_(2a)、H_(2b)、H_a)没有明显的变化。但是,随着细胞分化的进程,H_1 表现出明显的差异。在这四个时期中也可看到红细胞特有的组蛋白 H_5。文章讨论了组蛋白 H_1 在鲢鱼早期发育阶段对细胞分化的可能调节作用。

Allelopathic interactions between Potamogelon maackianus and Microcystis aeruginosa

The allelopathic interactions between Potamogeton maackianus and toxic cyanobacteria (Microcystis aeruginosa) were studied. P maackianus inhibited the growth of M. aeruginosa, both in a coexistence culture system and in exudates experimental culture system. M. aeruginosa also showed effects on the secondary metabolic biosynthesis and secreting behavior of P maackianus. The main lipophilic components of the hexane extracts and the exudates from the macrophyte were analyzed through GC-MS determination. The lipophilic components of the hexane extracts and the exudates from P. maackianus were influenced by M. aeruginosa or their released chemicals. Comparing the lipophilic constituents of the hexane extracts with those in the exudates, the results showed that weak polar compounds contained in the macrophytes can be secreted into the surrounding water. Many compounds, such as N-phenyl-2-naphthalenamine and isopropyl myristate, were detected both in the hexane extracts and the exudates. The changes of lipophilic components in the hexane extracts would be a response to the stress of toxic cyanobacteria or their released toxins. Those changes of exudates, especially the increased content of N-phenyl-2-naphthalenamine, might also be an induced defensive behavior mediated by the released toxins from M aeruginosa. The study results about reciprocal allelopathic responses between macrophytes and cyanobacteria can help in the management of eutrophic waters, and is also important information concerning strategies for recovering eutrophic waters.

Trophic relationship between the parasitic isopod ichthyoxenus japonensis and the fish carassius auratus auratus as revealed by stable isotopes

Stable carbon and nitrogen isotope analysis was used to investigate the host-parasite trophic relationship between the parasitic isopod Ichthyoxenus japonensis and one of its freshwater fish host Carassius auratus auratus from Lake Fuxian, China. No significant differences in delta C-13 and delta N-15 were observed between the heterosexual pairs of I. japonensis in the same host. delta C-13 and delta N-15 of I. japonensis were significantly lower than those of its host fish, and the isotopic ratios of the isopod increased with the increase of host fish isotopic signatures. Unlike isotopic fractionation patterns generally observed among consumers and their diets, isopod parasite was delta C-13 and N-15 depleted relative to the muscle tissue of this host fish. Differential isotopic fractionation patterns in the isopod parasite and the fish may be attributed to differences in parasite and host metabolism.

Cloning and expression of medaka dazl during ernbryogenesis and gametogenesis

The Deleted in azoospermia family consists of RNA-binding proteins Bottle, Daz, and Daz-like (Dazl) that are expressed in the germline. Here, we report the cloning and expression of the medakafish (Oryzias latipes) dazl gene (odazl). Interestingly, although the predicted medaka Dazl protein (oDazl) contains a RRM motif and a DAZ repeat characteristic of its mammalian homologs, it lacks 80 aa at the C-terminus. By RT-PCR, RNA in situ hybridization, Western blotting and fluorescent immunohistochemistry using a rabbit anti-DazI antibody (alpha Oazl), we analyzed the expression patterns of odazl and its protein. The odazl transcript persists throughout embryogenesis and delineates with primordial germ cells. In adults, the expression of odazl RNA and its protein is restricted to germ cells of both the testis and ovary. We observed differential expression of RNA and protein at critical stages of gametogenesis. In the testis, the odazl RNA is low at premeiotic stages, abundant at meiotic stages, but absent in postmeiotic stages; whereas the oDazl protein is rich in premeiotic stages, reduced at meiotic stages, becomes barely detectable or absent in postmeiotic round spermatids or sperm, respectively. This is in sharp mature spermatozoa. In the ovary, the odazl RNA contrast to the human situation where the Dazl transcript and protein are present in and protein persist throughout oogenesis and also show differential expression at premeiotic, meiotic and postmeiotic stages. Thus, the odazl or its protein is a marker for germ cells during embryogenesis and at critical stages of gametogenesis in both sexes of medaka. (c) 2006 Elsevier B.V. All rights reserved.

The diphasic nc-Si/a-Si : H thin film with improved medium-range order

A series of silicon film samples were prepared by plasma enhanced chemical vapor deposition (PECVD) near the threshold from amorphous to nanocrystalline state by adjusting the plasma parameters and properly increasing the reactions between the hydrogen plasma and the growing surface. The microstucture of the films was studied by micro-Raman and Fourier transform infrared (FTIR) spectroscopy. The influences of the hydrogen dilution ratio of silane (R-H = [H-2]/[SiH4]) and the substrate temperature (T-s) on the microstructural and photoelectronic properties of silicon films were investigated in detail. With the increase of RH from 10 to 100, a notable improvement in the medium-range order (MRO) of the films was observed, and then the phase transition from amorphous to nanocrystalline phase occurred, which lead to the formation of diatomic hydrogen complex, H-2* and their congeries. With the increase of T-s from 150 to 275 degreesC, both the short-range order and the medium range order of the silicon films are obviously improved. The photoconductivity spectra and the light induced changes of the films show that the diphasic nc-Si/a-Si:H films with fine medium-range order present a broader light spectral response range in the longer wavelength and a lower degradation upon illumination than conventional a-Si:H films. (C) 2004 Elsevier B.V. All rights reserved.

Optical properties of ZnSxTe1-x mixed crystals

The Raman scattering and the photoluminescence (PL) of ZnSxTe1-x mixed crystals grown by MBE, covering the entire composition range (0 less than or equal to x<1), were investigated. The results of Raman studies show that the phonons in ZnSxTe1-x mixed crystals display two-mode behavior. In addition, photoluminescence spectra obtained in backscattering and edge-emission geometries, reflection spectra and the temperature dependence of the photoluminescence of ZnSxTe1-x from 10 to 300K were employed to find out the origins of PL emissions in ZnSxTe1-x with different x values, The results indicate that the emission bands, for the samples with small x values, can be related to the band gap transitions or a shallow level emission center, while for the samples with large x values, they are designated to strong radiative recombinations of Te isoelectronic centers.

Study of microstructure of high stability hydrogenated amorphous silicon films by Raman scattering and infrared absorption spectroscopy

The microstructure, hydrogen bonding configurations and hydrogen content of high quality and stable hydrogenated amorphous silicon (a-Si:H) films prepared by a simple ''uninterrupted growth/annealing" plasma enhanced chemical vapor deposition technique have been investigated by Raman scattering and infrared absorption spectroscopy. The high stability a-Si:H films contain small amounts of a microcrystalline phase and not less hydrogen (10-16 at. %), particularly, the clustered phase hydrogen, Besides, the hydrogen distribution is very inhomogeneous. Some of these results are substantially distinct from those of conventional device-quality n-Si:H film or stable cr-Si:H films prepared by the other techniques examined to date. The stability of n-Si:H films appears to have no direct correlation with the hydrogen content or the clustered phase hydrogen concentration. The ideal n-Si:H network with high stability and low defect density is perhaps not homogeneous. (C) 1998 American Institute of Physics.

on lin-bose problem

This paper study generalized Serre problem proposed by Lin and Bose in multidimensional system theory context [Multidimens. Systems and Signal Process. 10 (1999) 379; Linear Algebra Appl. 338 (2001) 125]. This problem is stated as follows. Let F ∈ Al×m be a full row rank matrix, and d be the greatest common divisor of all the l × l minors of F. Assume that the reduced minors of F generate the unit ideal, where A = K[x 1,...,xn] is the polynomial ring in n variables x 1,...,xn over any coefficient field K. Then there exist matrices G ∈ Al×l and F1 ∈ A l×m such that F = GF1 with det G = d and F 1 is a ZLP matrix. We provide an elementary proof to this problem, and treat non-full rank case.

医院制剂生产管理系统的设计与实现

目的设计开发完整的医院制剂生产管理系统,使其满足物资的入出存管理和生产管理的需求。方法在细致分析医院制剂生产的管理流程的基础上,结合企业资源规划系统,采用客户端/服务器模式,应用SQLServer数据库管理系统和PowerBuilder开发工具设计、开发了该系统,主要由库存管理模块和生产管理模块组成,同时具有综合查询、报表输出和系统维护等功能。结果该系统能够与HIS连接,根据HIS销售情况制定生产计划,通过生产计划和现有库存快速制定采购计划,理顺了医院制剂室的工作流程,能够准确、快捷地输出相应的报表。结论该系统设计方案可行,系统操作简单,提高了工作效率,加强了医院的管理工作。

CO2置换开采天然气水合物研究进展

介绍了近年来CO2置换开采天然气水合物技术的研究进展；论述了CO2与天然气水合物中CH4置换反应在热力学上的可能性；认为正确理解置换反应机理、探索新的反应技术并提高反应速率是置换开采技术走向产业化的关键。