小鼠四倍体半克隆胚胎发育研究

半克隆(Semi-Cloned)胚胎是通过注射体细胞核到未去核的卵母细胞中产生的。在半克隆胚胎中,体细胞被用来作为精子的替代物。然而,由于异常的染色体分离,构建的半克隆胚胎在激活后形成了非整倍体而导致胚胎发育受到严重影响,不能发育到期。本研究通过抑制小鼠半克隆胚胎在激活过程中染色体数目减半,避免非整倍体胚胎形成,研究四倍体半克隆(TetraploidSemi-cloned,TSC)胚胎的发育和体细胞核的掺入对胚胎发育的影响。结果显示,TSC胚胎的体外发育率显著高于二倍体半克隆胚胎,与正常受精卵及孤雌激活对照无显著性差异,但TSC胚胎的细胞数在桑椹胚和囊胚期比正常二倍体受精胚胎和孤雌激活胚胎少。通过Oct-4染色发现,TSC胚胎囊胚期内细胞团(InnerCellMass,ICM)细胞很少或者没有。移植63个四倍体半克隆胚胎到3只假孕母鼠体内,得到20个胎盘,但没有得到胎儿。组蛋白乙酰化和DNA甲基化检测显示,部分TSC胚胎在囊胚期没有形成正常受精胚胎在ICM和滋养外胚层(Trophectoderm,TE)之间的差异分布。TSC胚胎的基因表达不依赖于细胞分裂次数而依赖于发育时间。虽然TSC胚胎避免了二倍体半克隆胚胎形成非整倍体现象,但由于TSC胚胎没有ICM细胞或ICM细胞很少,所以只能形成胎盘而不能形成胎儿。本实验第一次较为全面地研究了TSC胚胎的发育,同时也为研究体细胞核再程序化、基因打靶技术提供了一种新的途径。     

Interfamily pregnancy and expression of CD57, CD68 in deciduas between golden hamster and mouse

Pregnancy between different species is one of the key steps to interspecific somatic cell cloning. Although interspecific clone embryos have been constructed, they could not develop to birth after being transferred to recipi-ents. In order to clarify the mechanism of this phenomenon, interfamily pregnancy between golden hamste (Mesocricetus auratus) and mouse (Mus musculus) was studied. Co-culture results indicated that the adhesion ratios of golden hamster blastocysts on mouse uterine epithelia monolayer 12, 24, 48 and 72 h after co-culture were all significantly lower than those of mouse blastocysts. The outgrowth ratios of golden hamster blastocysts on mouse uterine epithelia monolayer 48, 72 h after co-culture were both significantly lower than those of mouse blastocysts (P < 0.01). Golden hamster抯 blastula could be implanted and develop to D 11 of pregnancy after being transferred to mouse uterus (the 7th day after embryo transfer). Compared to the transfer of mouse embryo to mouse uterus, the successful ratio of interfamily embryo transfer was lower and the bulk of fetus was smaller than that of intraspecific fetus. Compared to intraspecific preg-nancy of mouse, the remote decidual tissue of interfamily pregnancy on D8 is looser. At the same time, expressions of CD57 and CD 68 in remote deciduas were both higher than those in the secondary deciduas in both intraspecific and interfamily pregnancy. However, expressions of the two molecules in interfamily pregnancy were lower than those in intraspecific pregnancy. These results showed that interfam-ily pregnancy could be established between golden hamster and mouse. But the development of fetus in interfamily pregnancy was slower than that in intraspecific pregnancy. The expression difference of CD57 and CD68 indicates the difference of immunoreaction between interfamily and in-traspecific pregnancy, which may be one of the reasons lead-ing to interfamily pregnancy termination.     

Embryonic stem cell as nuclear donor could promote in vitro development of the heterogeneous reconstructed embryo

The nucleus of a somatic cell could be dedifferentiated and reprogrammed in an enucleated heterogeneous oocyte. Some reconstructed oocytes could develop into blastocysts in vitro, and a few could develop into term normally after transferred into foster mothers, but most of cloning embryos fail to develop to term. In order to evaluate the efficacy of embryonic stem cell as nucleus donor in interspecific animal cloning, we reconstructed enucleated rabbit oocytes with nuclei from mouse ES cells, and analyzed the developmental ability of reconstructed embryos in vitro. Two kinds of fibroblast cells were used as donor control, one derived from ear skin of an adult Kunming albino mouse, and the other derived from a mouse fetus. Three types of cells were transferred into perivitelline space under zona pellucida of rabbit oocytes respectively. The reconstructed oocytes were fused and activated by electric pulses, and cultured in vitro. The developmental rate of reconstructed oocytes derived from embryonic stem cells was 16.1%, which was significantly higher than that of both the adult mouse fibroblast cells (0%-3.1%, P < 0.05) and fetus mouse fibroblast cells (2.1%-3.7%, P < 0.05). Chromosome analysis confirmed that blastocyst cells were derived from ES donor cell. These observations show that reprogramming is easier in interspecific embryos reconstructed with ES cells than that reconstructed with somatic cells, and that ES cells have the higher ability to direct the reconstructed embryos development normally than fibroblast cells.     

Comparison of infection frequencies in fetus by maternal ascitic cancer and leukemia cells

It was demonstrated that maternal Ehrlich cells could infect fetus in a mouse model, which is another kind of the cancer cells inducing cancer cell infection between mother and fetus besides leukemia L615 cells reported previously by the authors. Among the fetus in a pregnancy only a few of them might be infected by the maternal cancer cells. The early and medial periods of pregnancy are the dangerious periods for the cancer infection. The infection frequencies for leukemia L615 cells and Ehrlich cells are 100% and 35%, respectively; but in the late period of pregnancy they are 4.5% and zero for leukemia L615 and Ehrlich cells, respectively. This indicates that the infection frequency for leukemia L615 cells is much higher than Ehrlich cells. The infection might be caused by infiltration or invasion of the cancer cells.     

Long-distance teleportation of qubits at telecommunication wavelengths

Matter and energy cannot be teleported (that is, transferred from one place to another without passing through intermediate locations). However, teleportation of quantum states (the ultimate structure of objects) is possible: only the structure is teleported--the matter stays at the source side and must be already present at the final location. Several table-top experiments have used qubits (two-dimensional quantum systems) or continuous variables to demonstrate the principle over short distances. Here we report a long-distance experimental demonstration of probabilistic quantum teleportation. Qubits carried by photons of 1.3 micro m wavelength are teleported onto photons of 1.55 micro m wavelength from one laboratory to another, separated by 55 m but connected by 2 km of standard telecommunications fibre. The first (and, with foreseeable technologies, the only) application of quantum teleportation is in quantum communication, where it could help to extend quantum cryptography to larger distances.     

利用高介电材料提高胎儿磁共振射频安全性理论研究

探究应用高介电材料(HDM)降低胎儿磁共振成像(fetus MRI)扫描中组织射频能量比吸收率(SAR)在理论上的可行性。建立13周胎儿和成人女性盆腔混合数值模型。通过计算机仿真计算1.5 T和3 T场强下普通扫描及应用不同HDM时的部分身体比吸收率(partial body SAR)和局部比吸收率(local SAR)的分布规律,以及两种场强下普通扫描和应用两种形状HDM取得最佳胎儿local SAR最大值时的B+1场均匀性。通过应用合适的HDM,能够显著降低1.5 T和3 T fetus MRI中的SAR值。在1.5 T和3 T成像时当取得最佳胎儿local SAR最大值时,分别可使胎儿local SAR最大值比普通扫描时下降12.90%和24.75%。这项研究表明通过应用合适的HDM,可以降低在临床上进行fetus MRI时的SAR值来提高胎儿的安全性。     

胎儿腹部囊性包块的产前超声诊断分析

目的探讨产前超声诊断胎儿腹部囊性包块的价值。方法回顾2007年1月-2010年10月在我院行产前超声检查发现的107例胎儿腹部囊性包块病例,对比分析其出生前后随访结果与超声。结果在107例胎儿腹部囊性包块病例中,胎儿肾源性囊肿、肠道闭锁畸形和卵巢囊肿最为常见,胎儿胆道囊性病变、泄殖腔畸形、淋巴管囊肿、肾上腺囊肿等较少见。结论超声能在胎儿孕18周后发现胎儿腹腔内囊性包块,并能根据包块的位置、大小、形态、血流及动态观察情况等特征判断包块的来源和性质。     

以精子载体法制备转基因小鼠的初步研究

将外源融合基因BaLA-HI与DOSPER脂质体等比较混合,加入获能精子悬液中,37度,5％CO2共培养0．5h,以这种处理精子作为转基因载体乾鼠的体外受精及胚胎移植,在获得的40只移植后代后,经PCR特异片段扩增和Southern杂交,共检测出2只呈相性的转基因小鼠,证明人胰 基因已在小鼠染色体上实现了整合,基因整合率为5％。     

网格环境下用并行路径传输文件的仿真与实现

文件传输时间的长短是评判一种传输机制传输效率的直接因素。本文针对如何提高大数据量文件的传输效率提出了一种新的传输方式。目的是为了缓解文件传输时网络发生拥塞或因带宽利用率不高时而出现无法传输的现象。本文主要研究了使用并行路径传精大数据量文件,以及在传输过程中若遇到未知的网络状况导致文件无法传输时动态管理副本传输的可行性。这种文件传输方式在加快文件传输速率,减少文件传输时间,提高传输稳定性等方面有明显效果。既完成了该传输模型的仿真效果,又针对仿真程序的结果完成了具体实现。本文对此分析了传统的单一副本数据传输方法以及多副本数据传输方法的区别,最后通过仿真程序和实现程序对三种传输方法做了比较。实验证明,基于网格环境下自适应动态路径文件传输模型具有较好的传输性能。     

胎牛成纤维细胞的分离培养

应用组织块培养法从胎牛耳部分离培养了胎牛成纤维细胞。应用PCR方法鉴别了细胞的性别。选择雌性成纤维细胞,进行了形态观察、生长曲线测定、染色体分析。结果表明,分离培养的细胞具有正常的大小、形态、分裂增殖特性和染色体数目。胎牛成纤维细胞的培养方法的建立以及其相关的生物学特性的分析,有利于给同种和异种体细胞克隆牛研究提供形态良好、染色体数目正常的供体细胞,同时也为体细胞转基因等其他领域的研究提供了基础条件。     

我国出生人口性别比异常偏高的危害、原因及刑法回应

本文首先阐述了我国出生人口性别比异常偏高的严重社会危害性,接着分析了导致人口性别比异常偏高的原因,指出滥用B超非法鉴定胎儿性别是导致这一问题的罪魁祸首,最后论述了非法鉴定胎儿性别行为的犯罪化问题,认为对该种行为不宜认定为非法行医罪,建议在修改《刑法》时增设“非法鉴定胎儿性别罪”。     

库车坳陷克拉苏冲断带传递型超压的识别、计算及其主控因素

超压可在断裂的沟通作用下发生垂向传递,目前对于断裂传递型超压的识别、计算和预测研究还比较薄弱。分析此类超压的成因,修正前人关于垂向传递型超压识别方法,以库车坳陷克拉苏冲断带盐下断裂发育的超压地层为例,通过含气声速校正和浮力校正,识别盐下断裂传递型超压,近似计算传递量,最终分析影响该区断裂传递超压量的主控因素。结果表明:克拉苏冲断带的大北和克拉苏地区的盐下地层均不同程度存在超压传递现象;超压的传递量在大北地区大北3井为24.10 MPa,在吐北2井为26.35 MPa,克拉苏地区的克拉2井平均为16.47 MPa,由断裂传递所产生的超压约占实测总过剩压力的50%;超压的传递量主要受断裂的断距、倾角及断裂穿越地层的过剩压力梯度的综合影响,是三者乘积的综合效应。     

Patterns of junctional communication in the early amphibian embryo

It has long been recognized that cells in early embryos can communicate with each other via a direct cell-to-cell pathway, probably mediated by gap junctions. Low electrical resistance pathways, detected electrophysiologically, have been identified in all species examined so far. However, studies in various embryos on the transfer of molecules larger than small ions (for example, fluorescent dyes in the molecular weight range 350-500) have given conflicting results. In all these studies the ability to transfer dyes from cell to cell was determined without reference to the position of the injected cell in the embryo. In the experiments reported here, cell-cell transfer of the fluorescent dye, Lucifer yellow (molecular weight (Mr) 450) was re-examined in the early Xenopus laevis embryo by injecting the dye into identified cells, as the position of the injected cell within the embryo may be important. At the 32-cell stage, we found that dye transfer often occurred between animal pole blastomeres which were not sisters, as well as between sister cells, and also that Lucifer yellow was indeed transferred via gap junctions. The cell-cell transfer was not uniform within the animal pole; transfer was maximal near the dorsal side and minimal at the ventral side. This pattern may reflect differences in permeability or numbers of gap junctions across the embryo, and could be related to early events in development.     

天然气分步捕获原理及在成藏研究中的作用

天然气生成具有阶段性,不同演化阶段形成的天然气的地球化学性质不同。构造的演化与圈闭的形成具有阶段性,因此不同阶段形成的圈闭可捕获不同演化阶段的天然气。源岩早期生成的天然气及形成的气藏可能由于后期构造活动遭散失或转移,使一些圈闭只能捕获源岩晚期生成的天然气,即圈闭对天然气的捕获具有阶段性,属于部分捕获而非连续捕获(或聚集)过程。介绍了天然气分步捕获的原理,并结合塔里木盆地塔北地区天然气地球化学特征,讨论了天然气分步捕获原理在成藏研究中的作用。     

模式识别中不同记忆编码的模式和模板的匹配

通过一项全部报告实验和两项抽样汉字识别实验,探讨了模式识别中不同记忆编码的模式和模板如何匹配的问题.实验结果显示:全部报告实验中,待识别汉字模式平均转换到短时记忆的量为3.64个,比进入到感觉记忆中的信息量(8个)少得多,这表明感觉记忆信息向短时记忆的转换受到了约束;抽样汉字识别实验1中,匹配汉字模式识别量与其转换量之间无显著差异(p＞0.5),说明转换到短时记忆的信息被等消耗识别;抽样汉字识别实验2中,匹配汉字模式识别量约为其转换量的2倍,差异显著(p＜0.001),基于受约束转换和等消耗识别现象,由模式识别信息来源的判据的判据可知,模式识别直接利用了感觉记忆编码的模式信息.抽样汉字识别实验2中,与模式进行匹配的模板只具有短时记忆编码,因此,有理由认为:模式和模板能以不同的记忆编码直接匹配.     

三种助产方法对猫难产的疗效比较研究

本文用催产素、催产素配合普鲁卡因封闭和剖腹产术对58例难产猫进行了助产,其疗效以手术助产方法为最高,有效率100％,催产素配合普鲁卡因封闭次之(60％),而催产素仅在21.5％的猫有效,并对猫发生难产的病因进行了分析:难产的发生与孕猫的胎次有密切关系,第一胎的难产发生率为61.8％,第二、三胎和三胎以上分别为29.4％、5.9％和2.9％,胎儿成活率与难产天数呈反比例关系。     

CHARACTERISTICS OF QUATERNARY AMMONIUM RESISTANT BACTERIA FROM A FINE PAPERMACHINE SYSTEM

To evaluate the biocide effect of quaternary ammonium chloride (QAC), a whitewater sample was taken from a fine papermachine headbox. By plate spreading method, 51 strains of facultative anaerobe were isolated morphologically. Then the strains were separately transferred to basal medium and were incubated before the beginning of log phase. To identify strains with different QAC resistance, 30-120 ppm of N-Alkyl-benzyl-dimethyl ammonium chloride were added to basal medium.Biocide effect was investigated by comparison of bacterial growth, which can be monitored by 600 nm light absorbance of basal medium suspension. Among 51 strains, only 2 strains can Survive for QAC concentration up to 120 ppm. API20E aud 16S rRNA gene sequencing technique were applied to identify two strains with highest (120 ppm)QAC resistance. One strain (HB22)was identified as Morganella morganii. HB22 can resist QAC concentration up to 150 ppm. HB22 is Gram-negative rod, motile with flagella, catalase positive, oxidase negative, Indole positive, H2S production negative, facultative anaerobe. HB22 has optimum growth condition of 35℃ and pH 7.0.HB22 can catabolize only glucose and D (+)-Mannose.The other (HB45) was identified with high similarity among Pseudomonas cf. monteili or Pseudomonas mosselii or Pseudomonas putida. HB45 can resist QAC concentration up to 200 ppm.HB45 is Gram-negative rod, motile with flagella,catalase positive, oxidase negative, Indole negative,H2S production negative, aerobe. HB45 has optimum growth condition of 30℃ and pH 7.4. HB45 can catabolize L-Arabinose, L(+)-Rhanmose, D (+)-Mannose, Glucose, Glycerol, Lactose, Maltose,Raffmose, Xylose, Cellulose and Xylan. The implication of this work to paper industry is also discussed.     

浅谈英语语言中的否定表达

在英语语言中，有否定词的句子，未必表达否定含义；没有否定词的句子未必表达肯定含义。按照其表达方式分类英语中的否定表达主要可分为两大类：“直接”否定，即句中含一些否定词或句中一些单词本身带有否定词缀，因此，对于否定含义完全可以一目了然；“间接”否定，即指从句子的字面上对于否定含义并不能一目了然，只是在词底里间接而含蓄地表达出否定的含义。按照其结构分类英语中的否定表达主要可分为八大类：一般否定、部分否定、转移否定、双重否定、接续否定、转换否定、省略否定和其他惯用否定结构。     

电流变体离合器的理论设计

现有工程机械通常采有接触摩擦片式离合器，这种装置的传递扭矩难以实现无级连续调节。介绍了电流变技术，以此为基础，设计出一种新型离合器，通过改变控制电压就可调节离合器的输出转速或扭矩。