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31.
Davila S Furu L Gharavi AG Tian X Onoe T Qian Q Li A Cai Y Kamath PS King BF Azurmendi PJ Tahvanainen P Kääriäinen H Höckerstedt K Devuyst O Pirson Y Martin RS Lifton RP Tahvanainen E Torres VE Somlo S 《Nature genetics》2004,36(6):575-577
Mutations in PRKCSH, encoding the beta-subunit of glucosidase II, an N-linked glycan-processing enzyme in the endoplasmic reticulum (ER), cause autosomal dominant polycystic liver disease. We found that mutations in SEC63, encoding a component of the protein translocation machinery in the ER, also cause this disease. These findings are suggestive of a role for cotranslational protein-processing pathways in maintaining epithelial luminal structure and implicate noncilial ER proteins in human polycystic disease. 相似文献
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本文简要地介绍了什么是往复流离子交换(简称 R.F.I.E.),它在与其它离子交换系统作比较时有些什么优点,以及该系统是如何操作的。本文列出了实验结果,但并未加以理论解释,作者之一 Hummel 教授将在《论离子交换法的改进》一文中(见本期)提出一个理论模型。本实验改进了分析精度,用残液浓度作为计算回收率的基准,从而提高了实验结果的精确性。本实验用两种不同外形、不同尺寸的树脂,测定了极限回收率,在1.5吋直径的柱子内测定了一系列数据。对100~200目树脂的一系列研究以获得百分回收率与再生比的函数关系,在该研究中再生比为2.16M 硫酸,负载为17.6%。实验曲线与理论曲线极相似,回收率在再生比为2.74时是90%,而再生比6.62时为99.65%。在实验条件下极限回收率为99.93%。 相似文献
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Sex determination and gametogenesis are key processes in human reproduction, and any defect can lead to
infertility. We describe here the molecular mechanisms of male sex determination and testis formation; defects in
sex determination lead to a female phenotype despite the presence of a Y chromosome, more rarely to a male
phenotype with XX chromosomes, or to intersex phenotypes. Interestingly, these phenotypes are often associated
with other developmental malformations. In testis, spermatozoa are produced from renewable stem cells in a complex
differentiation process called spermatogenesis. Gene expression during spermatogenesis differs to a surprising
degree from gene expression in somatic cells, and we discuss here mechanistic differences and their effect on the
differentiation process and male fertility.Received 23 January 2004; received after revision 30 March 2004; accepted 6 April 2004 相似文献
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Pappas G Panagopoulou P Christou L Akritidis N 《Cellular and molecular life sciences : CMLS》2006,63(19-20):2229-2236
Brucella has traditionally been considered a biological weapon. It was the subject of extensive offensive research in the past, and still belongs to category B pathogens on most lists. Its propensity for airborne transmission and induction of chronic debilitating disease requiring combined antibiotic regimens for treatment, its abundance around the world and its vague clinical characteristics defying rapid clinical diagnosis are some of the characteristics that apply to the pathogen's weapons potential. Yet minimal mortality, availability of treatment options, protracted inoculation period and the emergence of new, more virulent potential weapons means that its inclusion among agents of bioterrorism is nowadays mainly of historical significance. Nevertheless, in the interest of literacy and of avoiding panic, physicians and the public both should be aware of the most common zoonosis worldwide. 相似文献
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锆钛酸铅镧陶瓷(PLZT)应力偏压铁电光导器件已经报导过。他们所用结构为透射式,(在读出操作中,光通个整个器件)。透射式器件具有几个缺点:(a)对于读出光的波长,光导膜必须具有低的损耗。(b)在一个透射式的器件中,不能同时进行写入与读出,除非光导膜对读出光的波长没有反应。(c)假设希望低介入损耗,陶瓷片必须厚到足够产生一个完全半波长的延迟(一般需要片厚为150微米左右)。在应力偏压器件中,分辨率受到与片厚有关的边纹区域所限制(最小分辨元约为1/3片厚)。因此,陶瓷片尺寸必须足以适应所予期的信息元的数目,并且假设使用一个厚片,则器件的分辨率有明显的各向异性,(平行于张力的线条的分辨率小于垂直于张力的线条的分辨率)。在使用薄陶瓷片时,这个效应减少了。 相似文献
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The known galaxies most dominated by dark matter (Draco, Ursa Minor and Andromeda IX) are satellites of the Milky Way and the Andromeda galaxies. They are members of a class of faint galaxies, devoid of gas, known as dwarf spheroidals, and have by far the highest ratio of dark to luminous matter. None of the models proposed to unravel their origin can simultaneously explain their exceptional dark matter content and their proximity to a much larger galaxy. Here we report simulations showing that the progenitors of these galaxies were probably gas-dominated dwarf galaxies that became satellites of a larger galaxy earlier than the other dwarf spheroidals. We find that a combination of tidal shocks and ram pressure swept away the entire gas content of such progenitors about ten billion years ago because heating by the cosmic ultraviolet background kept the gas loosely bound: a tiny stellar component embedded in a relatively massive dark halo survived until today. All luminous galaxies should be surrounded by a few extremely dark-matter-dominated dwarf spheroidal satellites, and these should have the shortest orbital periods among dwarf spheroidals because they were accreted early. 相似文献