内胚层

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastocysts followed by fusion of cytoplasm and nucleus and cleavage in vitro. During the fusion of cytoplasm, the DNA methylation levels of the fused embryos are as high as these of two-cell diploid embryos in vivo Then the embryos are rapidly demethylated when the nucleus begin to fuse, resulting in the lowest DNA methylation levels when the nucleus are fused completely. After that, the DNA methylation levels of the fused embryos are gradually increased until the morula stage. However, whereas an asymmetric distribution of DNA methylation is established in vivo-derived blastocysts with a higher methylation level in the inner cell mass than that in the trophectoderm, we can not detect the asymmetric distribution in most in vitro-derived tetraploid blastocysts.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在桑葚胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastocysts followed by fusion of cyto-plasm and nucleus and cleavage in vitro. During the fusion of cytoplasm, the DNA methylation levels of the fused embryos are as high as these of two-cell diploid embryos in vivo Then the embryos are rapidly demethylated when the nucleus begin to fuse, resulting in the lowest DNA methylation levels when the nucleus are fused completely. After that, the DNA methy-lation levels of the fused embryos are gradually increased until the morula stage. However, whereas an asymmetric distribu-tion of DNA methylation is established in vivo-derived blastocysts with a higher methylation level in the inner cell mass than that in the trophectoderm, we can not detect the asymmetric distribution in most in vitro-derived tetraploid blastocysts.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在桑葚胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Morphorgenesis and differentiation of these organs involves sequential and complex interaction between ectoderm, mesoderm and endoderm.

这些器官的成型与分化，皆是由胚胎外、中、内三个胚层组织一连串的讯息传递以及彼此之间的交互作用所完成的。

Then, under the control of systemic factors, mesenchymal cells aggregate and differentiate to form catilage blastemal elements that prefigure skeletal limb components.

脊椎动物胚胎期骨与关节系统的发生是一种复杂生命现象，起始于中胚层间充质细胞的定向聚集，形成肢芽，然后在一系列作用因子的调控下，肢芽内细胞进一步分化，形成具有骨骼雏形的软骨原基，后者经软骨内骨化发育成骨。

BACKGROUND: Embryonic stem cells develop from early blastular inner cell mass. Under proper condition, ESCs can maintain undifferentiated state in vitro, normal diploid nuclear type, and proliferative potential. In addition, ESCs possess multi-directional differentiation capacity and can differentiate into all sorts of cells of three germ layers.

背景：胚胎干细胞来源于发育早期囊胚的内细胞团，适当条件下能在体外维持未分化状态、正常二倍体核型及无限增殖能力，且具有多向分化潜能，能够发育分化成机体3个胚层的所有类型细胞。

The 28S rDNA molecular phylogenetic trees showed: 1 entoprocts and phylactolaemate ectoprocts constituted a sister group, strenghthening the opinion that entoprocts should be reunited into phylum Bryozoa; 2 the cheilostome gymnolaemates was obviously non-monophyletic; 3 bryozoans itself was polyphyletic beyond any doubt, its main lineages were scattered in different positions of the lophotrochozoan trees; 4 to our great interests, the phylogenetic position of cheilostomes was between the diploblastic and the triploblastic, indicating they may play an important role during the evolution route from the diplobastic to the triploblastic animals.

28S rDNA分子系统树显示，内肛动物和被唇类外肛动物聚在一起并互为姐妹群，支持将内肛动物重新归入苔藓动物门的结论；唇口目裸唇类外肛动物绝非单系发生；苔藓动物本身也不是单系发生的，其主要类群分别位于触手冠担轮动物系统树的不同位置，特别是，唇口目苔藓动物的系统地位介于二胚层动物和其它三胚层动物之间，可能是二胚层动物向三胚层动物演化过程中的一个关键类群。

We generated EG4-GFP cell lines expressing enhancing green fluorescence protein which still maintained typical characteristics of pluripotent stem cells. We microinjected green cells into perivitelline of 8-cell stage embryos as well as aggregated them to 8-cell stage embryos with zona pellucida removed, to investigate developmental fate of EG4-GFP cells during formation of chimeric blastocysts.

我们建立了稳定表达绿色荧光蛋白的EG细胞系（EG4-GFP），发现该细胞仍能保持野生型的一般生长特性；通过显微注射和体外聚集得到细胞与8-细胞受体胚胎共同发育形成的嵌合胚，发现转基因细胞参与了胚胎早期发育过程中的生长与分化，大部分细胞集中于内细胞团，也有细胞分化为滋胚层细胞。

Compared to other elements content in different parts of different genotypes of wheat grains, we can find that there was extremely remarkable linear relations between the content of Pb and Cd

植物受重金属的污染往往是多种重金属的复合污染[15]，通过比较不同基因型水稻籽粒同一部位和不同部位Cd含量的差异，发现对Pb、Cd积累的部位差异是一致的，均是糊粉层累积最多，内胚乳最少。

No US-pin plastic treatment therapy, a comprehensive alternative to traditional plastic injection of the United States (with the needle and micro-needle) is efficient, non-invasive and safe,"mesoderm into beauty therapy" is the latest technology of water use and water channel protein electrophoresis principle of development Note the infiltration hole electric technology to non-needle injection principle, the use of "point to a plane," AMD permeation technology in skin electroporation Act under the influence of pulsed current stimulation, so that pores have a physical reaction to the rapid spread in two seconds 650-800 of fine pores, forming an instant electronic delivery channels of nutrition, nutrition Note dialysis therapy immediately with electrophoresis, soft laser stimulation and ice, etc., in the most secure and fast, the skin will be required for nutritional products , 99% transmitted to the basal cells, and can be stored as long as 72 hours, the skin smooth and more compact, creating a perfect Beautiful Skin.

无针美塑治疗疗法，是全面替代传统注射美塑的高效、无创，安全的&中胚层导入美容疗法&，是运用最新技术水电泳和水通道蛋白原理研制出的电孔注渗技术，以无针注射原理，采用&点到面&超微渗透技术，其电穿孔法令肌肤在脉冲电流刺激影响下，使毛孔产生物理反应，在两秒内迅速张开650-800个微细毛孔，瞬间形成电子营养输送通道，营养注渗疗法随即展开，配合电泳、柔激光和冰封等刺激作用，在最安全和快速的情况下，将皮肤所需的营养产品， 99%输送到基底层细胞，并可储存72小时之久，令肌肤更紧致柔滑，缔造无瑕美肌。

Here, we present a patient who received emergency right salpingo-oophorectomy for the wrong impression of torsion of ovarian cyst. The pathology turned out to be EST.

谨提出一例初误诊为卵巢囊肿扭转，接受急诊开刀切除右侧卵巢，后病理证实为内胚层窦肿瘤。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐