开始发育

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

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，在囊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。

Twenty-six of them wereeach given this drug lmg daily after the first coition during the cycle,and 12 womenused 2 mg for once for postcoital contraception.

所有服药妇女的子宫内膜发育均受不同程度抑制，对在周期早期开始服药者内膜的抑制作用较后期服药者明显。

In view of geological records preserved from different regions of the world are not identical, it's suggested that, when correlating the Ordovician-Silurian boundary, at the global boundary stratotype section, the FAD of N. persculptus be selected as the biomark, the transgression event identical to the FAD of N. persculptus as the auxiliary physical mark and the mass extinction and chemical anomaly events respectively as the auxiliary biomark and chemomark. In some regions with few graptolite, the Ordovician-Silurian boundary should be indicated by the auxiliary marks, such as the transgression event, mass extinction or chemical anomaly event, with the other fossil such as conodont nearest to other geological events as the provincial biomark for correlation. In other regions with much stratigraphic hiatus originated from the regression, the Ordovician-Silurian boundary should be marked by the regression-transgression event nearly relevant to the N. persculptus Zone.

鉴于不同地区留下的地质记录不完全相同，奥陶/志留系界线对比方法不同：在界线层型剖面上，以N.persculptus的首现为生物标志，以与之基本一致的海侵事件为辅助的物理标志，以生物集群绝灭事件和化学异常事件为辅助的生物和化学标志；在笔石极不发育的地区，则以海侵事件、生物绝灭事件或化学异常事件为辅助标志，以与其相距最近、并且具有区域对比性的其它门类化石作为界线对比的生物标志；对于由于海退事件所造成地层缺失很多的地区，则以海退/海侵事件作为划分界线的物理标志，并以相映的海侵事件的开始作为奥陶/志留系的分界。

Origin, developmental changes and homologies of the stage morphostructures were considered according to their location in three morphogenetic fields. The first, or central, field forms at the prodissoconch I stage. It can be inherited by prodissoconch II and nepioconch stages in one taxa, or PD-II, N and dissoconch stages in others. The second, or postero-dorsal, field appears at the N stage, and the third field, or antero-dorsal, at the D stage.

主要对3个形态发生区域的阶段形态结构的起源、发育变化和同源性做了研究，其一，即中央区域，开始形成于前双壳I期，在某个分类单元它可以在前双壳II期和幼贝期形成，而在其它分类单元则在前双壳II期、幼贝期和双壳期形成；第二区域，即背部后区，在幼贝期出现；第三区域，即背部前区，出现于双壳期。

Embryology The study of the development of embryos, usually from fertilization.

胚胎学：是研究胚胎发育的学科，通常从受精开始。

We observed highly significant changes of fiber orientations at regions that correspond to the superior longitudinal fasciculus during the first 5 years.

我们发现在出生后的开始5年，上纵束相关纤维束的区域定向发生明显改变。这个结果说明上纵束的轴突和髓鞘发育很慢，而这个区域被认为和语言功能相关。

Study of rice floral development has become a new focus of plant molecular genetics.

对水稻花发育的研究已开始成为植物分子遗传学的一个新的焦点。

Because, although fluorescent screen is given out X line dosage won't cause materiality to damage to the mother, but to just beginning be pregnant with fetal, the likelihood is the cause that causes abortion and abnormal growth, what is more,the rather that ray can be inside the mother's body save up, for this, moxa heart covers proposal pregnant woman

因为，虽然荧光屏发出的x线剂量对母亲不会造成实质性损害，但对刚开始孕育的胎儿，可能是导致流产和畸形发育的原因，何况射线会在母体内蓄积，为此，艾德蒙建议孕妇

Pre-Sinian of Huabei Platform was in the phase of geosyncline development and became stabilized in Sinian, then turned to platform development phase.

华北地台前震旦纪为地槽发展阶段，震旦纪开始稳定，并转向地台发育阶段。

In viewof geological records preserved from different regions of the world are not identical, its suggested that, whencorrelating the Ordovician-Silurian boundary, at the global boundary stratotype section, the FAD of N.persculptus be selected as the biomark, the transgression event identical to the FAD of N. persculptus as theauxiliary physical mark and the mass extinction and chemical anomaly events respectively as the auxiliarybiomark and chemomark. In some regions with few graptolite, the Ordovician-Silurian boundary should beindicated by the auxiliary marks, such as the transgression event, mass extinction or chemical anomaly event,with the other fossil such as conodont nearest to other geological events as the provincial biomark forcorrelation. In other regions with much stratigraphic hiatus originated from the regression, theOrdovician-Silurian boundary should he marked by the regression-transgression event nearly relevant to the N.persculptus Zone.

鉴于不同地区留下的地质记录不完全相同，奥陶／志留系界线对比方法不同：在界线层型剖面上，以N.persculptus的首现为生物标志，以与之基本一致的海侵事件为辅助的物理标志，以生物集群绝灭事件和化学异常事件为辅助的生物和化学标志；在笔石极不发育的地区，则以海侵事件、生物绝灭事件或化学异常事件为辅助标志，以与其相距最近、并且具有区域对比性的其它门类化石作为界线对比的生物标志；对于由于海退事件所造成地层缺失很多的地区，则以海退／海侵事件作为划分界线的物理标志，并以相映的海侵事件的开始作为奥陶／志留系的分界。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。