分割正方形

在右图中,每次在正方形内画上4条线段可以将这个正方形分割成5块。如果反复地进行30次,那么原来的正方形一共可以被分割成多少块?图中正方形和三角形分别可以数出多少个来呢?     

白细胞图像分割

研究从血液细胞中分离出白细胞,采用数学形态学的方法对图像进行预处理,使用灰度阈值法分割出白细胞核,定位出细胞的具体区域,用面积最大法提取整个白细胞。实验结果表明,本文提出的方法可以正确有效的分离出白细胞。     

半自动图像分割

半自动图像分割是图像分割的方法之一,本文提出了一种半自动图像分割的方法,即首先用手工粗略地将图像中的对象勾画出来,将图像划分为目标区域和背景区域,再利用边缘检测、最佳阈值分割、数学形态学等算法对图像的目标区域边缘进行优化,通过大量试验,得到精确的对象形状信息。     

彩色图像分割综述

图像分割是进行图像理解的基础，是图像工程技术中的一个重要问题。近几年来，人们越来越重视彩色图像的分割算法，并期望寻求一种实时性、鲁棒性较好的算法，本总结了近几年出现的彩色图像分割技术进行了讨论。     

基于遗传算法最佳阈值分割的矿石图像分割

为了实现选矿的自动化,通过利用工业摄像机对传送带上的矿石颗粒图像进行采集,Matlab对采集的图像依次进行双边滤波降噪处理、遗传算法最佳阈值分割、分水岭分割、矿石颗粒像素标定以及像素面积检测的方法研究了矿石的粒度分布,结果表明：与人工筛分的数据进行对比,显示图像处理的结果在误差允许范围内。可见运用图像处理的方法进行矿石粒度的检测是可行的,能够为矿石的破碎提供数据指导,促进矿业生产的自动化和智能化。     

半自动图像分割

半自动图像分割是图像分割的方法之一,本文提出了一种半自动图像分割的方法,即首先用手工粗略地将图像中的对象勾画出来,将图像划分为目标区域和背景区域,再利用边缘检测、最佳阈值分割、数学形态学等算法对图像的目标区域边缘进行优化,通过大量试验,得到精确的对象形状信息。     

基于条件分割对抗网络的超声甲状腺结节分割

提出一种基于条件分割对抗网络(conditional segmentation adversarial network, cSegAN)的超声甲状腺结节分割模型。模型由分割器网络和判别器网络两个部分组成，其中分割器网络设计使用一种多扩张率卷积块联合对结节区域进行准确定位，通过学习提取结节深度和浅层特征信息，获得结节区域二值掩膜；判别器网络对比分割结果与金标准之间的差距对分割结果进行评估。经多次对抗训练，实验结果表明，本文所提模型像素精度达到0.953 1,优于其他分割模型，可以更加准确地实现超声甲状腺结节分割。     

利用多重直方图分割方法分割致密影像中的物体

本文以乳腺Ｘ光片图像的分析研究为例，介绍了一种多次利用灰度直方图信息自动分割致密影像中物体影像的方法。     

胚胎分割、分割胚的体外培养及移植

用玻璃微针对小鼠胚胎进行分割,分割的裸半胚经体外培养和移植到受体后,获得由半胚发育的仔鼠。小鼠早期胚胎(2细胞,8细胞阶段)在链霉蛋白酶中软化透明带后,用直径为0.5μm的玻微针徒手对胚胎进行切割。切割的半胚体外培养24～48h,观察半胚的活力、发育率、发育阶段及胚泡的大小与未切割的正常胚胎进行比较。共切割胚胎342枚,切割后成活的半胚为411枚,半胚成活率为60.08％(411/682)。2细胞和8细胞阶段切割的半胚,成活率分别为     

从有限分割到无限分割的一类几何问题

本文将直接利用归纳原理,采用一些异乎寻常的方法来探讨几类几何问题。文中涉及的问题均是“至多可得”的情况。     

Effects of different nuclear recipients on developmental potential of mouse somatic nuclear transfer embryos

Somatic cell nuclear transfer has been succeeded in procedures of nuclear transfer. One is single nucleartransfer, the other is serial nuclear transfer. Viable animals have been cloned in different species using both me-thods[1—6]. Different nuclear recipients and donors wereused in serial nuclear transfer, namely, transferring thenuclear of reconstructed embryo into enucleated MⅡoocytes[7], transferring the nuclear of reconstructed em-bryos at one cell stage into enucleated zygote[4] and t…     

小鼠精子微注射受精卵的体外发育与移植的研究

用显微注射方法,将精子注入小鼠卵母细胞卵周隙中,使精卵体外受精获得受精卵。并对精子注射后卵母细胞的成活率、受精率和受精卵的发育率以及移植后受胎率等方面进行了系统的研究,结果表明:卵子存活率为75.36％(1309/1737),其中264枚卵裂,受精率为20·17％(264/1309),卵裂卵经体外培养后有192枚发育到桑椹胚及胚泡期,发育率为72.73％(192/264)。将其中73枚(桑椹胚10枚,肛泡63枚)胚胎移植到10只假孕受体子宫中,一只受体妊娠产仔9只,仔鼠发育正常。     

Aberrant DNA methylation in cloned ovine embryos

By using the approach of immunofluorescence staining with an antibody against 5-methylcytosine （5MeC）, the present study detected the DNA methylation patterns of cloned ovine embryos. The embryos derived from in vitro fertilization were also examined for reference purpose. The results showed that： （1） during the preimplantation development, cloned embryos displayed a similar demethylation profile to the fertilized embryos; that is, the methylation level decreased to the lowest at 8-cell stage, and then increased again at morulae stage. However, methylation level was obviously higher in cloned embryos than in stage-matched fertilized embryos, especially at 8-cell stage and afterwards; （2） at blastocyst stage, the methylation pattern in cloned embryos was different from that in fertilized embryos. In cloned blastocyst, inner cell mass （ICM） exhibited a comparable level to trophectoderm cells （TE）, while in in-vitro fertilized blastocyst the methylation level of ICM was lower than that of TE, which is not consistent with that reported by other authors. These results indicate that DNA methylation is abnormally reprogrammed in cloned embryos, implying that aberrant DNA methylation reprogramming may be one of the factors causing cloned embryos developmental failure.     

体外培养时间和表皮生长因子对牦牛卵母细胞成熟及孤雌胚胎体外发育的影响

研究在成熟液中添加表皮生长因子（Epidermal growth factor,EGF）以及成熟时间对牦牛卵母细胞体外成熟及孤雌胚胎体外发育的影响,以确立牦牛卵母细胞体外成熟的最佳体系.结果表明,成熟液中添加EGF组的成熟率明显高于未添加组（P＜0.05）,并且牦牛卵母细胞的成熟率随着EGF添加的浓度增加也不断上升;随着体外培养时间的延长,成熟率逐渐增加,培养24 h后成熟率趋于稳定;胚胎体外培养液中添加EGF能显著提高孤雌胚胎的8-细胞和囊胚形成率（P＜0.05）.由此推测：在体外培养22-24 h,且添加40 μg/mL EGF最有利于牦牛卵母细胞体外成熟;胚胎培养液中添加40μg/mLEGF能显著提高牦牛孤雌胚胎的体外发育能力.     

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.     

牛胚胎体外生产技术的应用研究

利用屠宰牛卵巢抽出的卵母细胞，以卵裂率和囊胚发育为标准，对牛胚胎体外生产过程进行了简化试验，结果显示：不加卵丘细胞的高密度卵母细胞体外成熟（１００－２００枚／平皿）可代替加卵丘细胞标准密度培养，其卵裂率和囊胚发育率没有显著变化，体外授精时间可从成熟培养后２２小时延长至２７小时，卵裂率和囊胚发育率均没有显著变化。卵母细胞体外成熟后可以不经洗涤直接移入受精滴，原成熟培养皿内残留孵丘细胞再培养４８小时形     

兔卵输卵管培养与再移植后的成活力

本文研究分裂的兔卵在输卵管内培养与再移植。目的是观察这种胚胎的成活力,验证这种方法的实用价值。分裂期的兔卵在输卵管内培养2～3天,发育到胚泡,然后再移植。移植分自体移植和异体移植。总共再移植24例,13例母兔妊娠,产仔9窝,获仔兔21只,怀孕率54.17％,成活率25.61％.     

Apoptosis of transgenic cloned and recloned bovine blastocysts

Apoptosis plays an important role in preimplantation embryonic development. Investigating mechanisms of apoptosis can provide useful information for obtaining high-quality embryos and help to improve cloning efficiency. Here, we investigated the incidence of blastomere apoptosis in transgenic blastocysts generated by somatic cell nuclear transfer (SCNT) and recloning using a terminal deoxynucleotidyl transferase-mediated d-UTP nick end-labeling (TUNEL) assay. Transgenic recloned embryos were the second generation SCNT embryos derived from the somatic cells of a transgenic SCNT calf. The blastocyst rate of transgenic SCNT embryos was lower than that of nontransgenic SCNT embryos. The incidence of apoptosis in transgenic SCNT embryos was higher than that of nontransgenic SCNT embryos. The blastocyst rate and the incidence of apoptosis in transgenic recloned embryos were similar to nontransgenic SCNT embryos. The process of donor cell transfection and drug selection may decrease the developmental capacity of transgenic SCNT embryos. Serial cloning did not influence the developmental capacity of transgenic recloned embryos.     

Embryonic and extraembryonic stem cell lines derived from single mouse blastomeres

The most basic objection to human embryonic stem (ES) cell research is rooted in the fact that ES cell derivation deprives embryos of any further potential to develop into a complete human being. ES cell lines are conventionally isolated from the inner cell mass of blastocysts and, in a few instances, from cleavage stage embryos. So far, there have been no reports in the literature of stem cell lines derived using an approach that does not require embryo destruction. Here we report an alternative method of establishing ES cell lines-using a technique of single-cell embryo biopsy similar to that used in pre-implantation genetic diagnosis of genetic defects-that does not interfere with the developmental potential of embryos. Five putative ES and seven trophoblast stem (TS) cell lines were produced from single blastomeres, which maintained normal karyotype and markers of pluripotency or TS cells for up to more than 50 passages. The ES cells differentiated into derivatives of all three germ layers in vitro and in teratomas, and showed germ line transmission. Single-blastomere-biopsied embryos developed to term without a reduction in their developmental capacity. The ability to generate human ES cells without the destruction of ex utero embryos would reduce or eliminate the ethical concerns of many.