氟对花背蟾蜍急性不良反应研究

为了解氟对花背蟾蜍(Bufo raddei)的受精卵及蝌蚪的急性不良反应.本研究以花背蟾蜍为研究对象,观察不良反应行为并测量氟对不同发育期花背蟾蜍(受精卵,10、30和50日龄)的半致死质量浓度(LC50)和安全质量浓度(SC).结果显示,随着质量氟浓度的增高,其对受精卵发育的抑制作用增强. 96 h后,氟对10、30和50日龄花背蟾蜍的LC50分别为333、493和678 mg/L,SC分别为3、5和7 mg/L. LC50和SC均随花背蟾蜍日龄的增加而不断升高,花背蟾蜍的受精卵及幼体对氟不良反应较敏感.     

花背蟾蜍(Bufo naddei Strauch)的早期胚胎发育及分期

花背蟾蜍 Bufo raddei Strauch 是兰州地区一种常见的、数量较多的无尾两栖类.本文详细研究了20℃条件下它的正常胚胎发育分期及其外部形态变化.根据胚胎的形态特征,花背蟾蜍的早期胚胎发育可以分成25个时期.从人工授精开始到蝌蚪的鳃盖封闭为止,共需185.1小时,比黑斑蛙 Rana nigromaculata 和中华大蟾蜍 Bufo bufo gargarizans 要快.花背蟾蜍发育过程的形态特征和其它无尾两栖类相似.但在某些方面有所不同.本文对它们的早期发育进行了分析和比较.     

北京无尾两栖类杂交实验

一、将北京所产的6种无尾两栖类作相互杂交实验。除了狭口蛙一种没有成功外,其余5种的互相杂交可以归并于下列5类:1.能够发育成幼蟾或幼蛙者有大蟾蜍与花背蟾蜍或黑斑蛀与金线蛙的相互交配。2.发育至蝌蚪期的有金线蛙♀X 花背蟾蜍(?)的少数受精卵。3.发育至囊胚期的有哈士蟆♀X 黑班点(?)。4.只能使卵产生不规则的卵裂沟的有黑斑蛙♀X 花背蟾蜍(?)或哈士蟆(?),金线蛙♀X 大蟾蜍(?),金线蛙♀X 花背蟾蜍(?)的多数精受卵。5.没有卵裂现象的有大蟾蜍♀X 黑斑蛙(?)或金线蛙(?)或哈士蟆(?),花背蟾蜍♀X 黑斑蛙(?)或金线蛙(?)或哈士蟆(?),黑斑蛙♀X 大蟾蜍(?),金线蛙♀(?)哈士蟆(?),哈士蟆♀X 大蟾蜍(?)或花背蟾蜍(?)。二、自大蟾蜍与花背蟾蜍相互杂交得到在形熊上不同的蟾蜍,说明了大蟾蜍和花背蟾蜍的卵细胞质是不同的。虽然自相互交配所得的杂种蟾蜍的染色体是相同的,但是由于卵细胞质或其含物的不同,也能够影响它们的胚胎发育,说明了在发育过程中,细胞核与细胞质的相互关系。     

重金属镉对花背蟾蜍蝌蚪生长发育的影响

研究了镉质量浓度在0.0015,0.0300和0.1500mg/L时对花背蟾蜍(Bufo raddei)蝌蚪生长发育的影响。结果表明:不同质量浓度镉能缩短花背蟾蜍蝌蚪50％出膜时间,但对蝌蚪最终孵化率没有影响;镉能影响蝌蚪的生存率,对蝌蚪的生长发育具有明显的抑制作用(P<0.01),但组间差异均不显著(P>0.05);同时各质量浓度水平均导致蝌蚪头部泡状膨大、‘S’型尾和体形奇小(为正常体长的0.50～0.67)等,致畸率0.1500 mg/L质量浓度水平最高(2.25％),0.0300 mg/L水平次之(2.00％),0.0015 mg/L水平最低(0.50％)。     

花背蟾蜍性腺分化的组织学观察

通过组织学方法观察了花背蟾蜍(Bufo raddei)原始生殖细胞(PGCs)的迁移、生殖嵴的形成、初生性腔的形成及性腺的分化。以期待提供更多有关花背蟾蜍的生物学资料。结果表明:花背蟾蜍生殖嵴是由PGCs迁入至腹腔静脉腹侧的背肠系膜后,与此处的体细胞共同形成。当蝌蚪发育至Gosner 23期时生殖嵴出现;Gosner 27期生殖嵴中央部位可观察到小的裂隙,即初生性腔;Gosner 33期在部分个体的原始生殖腺中可观察由初生性腔演化而成的次生性腔,将分化为雌性的标志;Gosner 38期部分个体原始生殖腺中可观察精小囊以及初级精原细胞,即将要分化为雄性的标志。花背蟾蜍生殖腺的分化和发育与中国林蛙、泽蛙等两栖类基本相同,但在生殖嵴和初生性腔的形成均早于它们。     

花背蟾蜍角膜和皮肤蛋白质的SDS-PAGE分析

本文用梯度SDS-PAGE方法,分析和比较了花背蟾蜍蝌蚪和成体皮肤及成体角膜中蛋白质组分的异同,结果表明成体角膜约有33种蛋白质组分;成体皮肤约有27种;蝌蚪皮肤约24种.蝌蚪皮肤与成体皮肤蛋白质组分数量和分布趋势相似,但成体皮肤的组分比蝌蚪的多,一些蛋白质组分的相对含量与蝌蚪的有差别.角膜与前两者相比差别明显,一是蛋白质组分数较多,其次分布趋势差异较大.     

蟾蜍和麻蜥肝脏及肺组织中低分子蛋白的SDS-PAGE比较分析

用SDS-聚丙烯酰胺凝胶电泳和银染显色法对花背蟾蜍和密点麻蜥肝脏和肺组织中的低分子蛋白质进行了分析．结果表明，花背蟾蜍和密点麻蜥的肝脏和肺组织中蛋白务带分别为21、14、23、16.二者肝脏和肺组织均有各自的特异性务带，且肝脏中蛋白务带多于肺组织．密点麻蜥肝脏和肺组织中蛋白质务带均多于花背蟾蜍．     

哈尔滨地区花背蟾蜍种群生态初步研究

2009年4-9月,对哈尔滨地区花背蟾蜍的种群生态进行初步调查.结果表明:该地区花背蟾蜍的四种典型生境是池塘、湿地、退化湿地和沙丘;花背蟾蜍的种群数量随季节呈规律性变化;繁殖期主要生活在池塘及岸边,繁殖后主要在湿地及退化湿地,冬眠集中在沙丘.     

花背蟾蜍的实验室养殖技术

两栖类胚胎发育在胚胎学、发育生物学及细胞生物学的研究中占有重要位置,而温度对两栖类胚胎发育有着十分重要的作用.花背蟾蜍（Bufo raddei Strauch）是兰州地区一种常见的、数量较多的无尾两栖类.本文就20℃条件下,从人工授精开始到蝌蚪的鳃盖封闭直至变态为幼蟾的整个实验室养殖技术作一报道.     

花背蟾蜍蝌蚪变态期角膜发育过程中Ⅰ型胶原的免疫组化彩色图像分析

应用彩色图像分析技术对Ⅰ型胶原的免疫组化彩色图像分析可以弥补单纯应用定性指标或形态学指标的不足。花背蟾蜍蝌蚪在变态期角膜发育过程中随着Ⅰ型胶原的增多，内、外角膜逐渐愈合。Ⅰ型胶原的表达存在增龄变化，可以推测Ⅰ型胶原是构成角膜基质的主要成分，对建立和维持角膜支架有重要作用。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that