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[转载]Nozzle: a report generation toolkit
chuangma2006 2013-5-22 03:21
Nozzle: a report generation toolkit for data analysis pipelines Nils Gehlenborg 1 , 2 , Michael S. Noble 2 , Gad Getz 2 , Lynda Chin 2 , 3 and Peter J. Park 1 , * + Author Affiliations 1 Center for Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA, 2 Cancer Program, Broad Institute, Cambridge, MA 02142, USA and 3 Department of Genomic Medicine, MD Anderson Cancer Center, Houston, TX 77230, USA ↵ *To whom correspondence should be addressed. Received January 10, 2013. Revision received February 10, 2013. Accepted February 13, 2013. Abstract Summary: We have developed Nozzle, an R package that provides an Application Programming Interface to generate HTML reports with dynamic user interface elements. Nozzle was designed to facilitate summarization and rapid browsing of complex results in data analysis pipelines where multiple analyses are performed frequently on big datasets. The package can be applied to any project where user-friendly reports need to be created. Availability: The R package is available on CRAN at http://cran.r-project.org/package=Nozzle.R1 . Examples and additional materials are available at http://gdac.broadinstitute.org/nozzle . The source code is also available at http://www.github.com/parklab/Nozzle . Contact: peter_park@hms.harvard.edu
个人分类: R|1979 次阅读|0 个评论
[转载]NIPD by NGS (2012 ppt)
genesquared 2013-2-6 10:44
Advanced Technology Behind the Harmony Test http://www.ariosadx.com/for-providers/rep_617_v3_0812_web_pdf.pdf ============== Non-invasive prenatal detection of aneuploidy by targeted next generation sequencing http://www.birminghamgenetics2012.org/pdfs/spoken/tuesday/5.4.pdf Helen White Senior Clinical Lecturer National Genetics Reference Lab (Wessex) http://www.birminghamgenetics2012.org/pdfs/spoken/tuesday/5.4.pdf
个人分类: prenatal|0 个评论
[转载]这里有分子生物学高手吗?求文献中的软件(打不开文献中的网址)
yijiusier 2013-1-8 11:21
文献出处: Gontcharova V., Youn E., Wolcott R.D., Hollister E.B., Gentry T.J., Dowd S.E. Black box chimera check (B2C2): a windows-based software for batch depletion of chimeras from bacterial 16S rRNA gene datasets . The open microbiology journal. 2010, 4: 47-52. Abstract: The existing chimera detection programs are not specifically designed for "next generation" sequencedata. Technologies like Roche 454 FLX and Titanium have been adapted over the past years especially with the introduc-tion of bacterial tag-encoded FLX/Titanium amplicon pyrosequencing methodologies to produce over one million 250-600 bp 16S rRNA gene reads that need to be depleted of chimeras prior to downstream analysis. Meeting the needs ofbasic scientists who are venturing into high-throughput microbial diversity studies such as those based upon pyrosequenc-ing and specifically providing a solution for Windows users, the B2C2 software is designed to be able to accept filescontaining large multi-FASTA formatted sequences and screen for possible chimeras in a high throughput fashion. Thegraphical user interface (GUI) is also able to batch process multiple files. When compared to popular chimera screeningsoftware the B2C2 performed as well or better while dramatically decreasing the amount of time required generatingand screening results. Even average computer users are able to interact with the Windows .Net GUI-based applicationand define the stringency to which the analysis should be done. B2C2 may be downloaded from http://www.researchandtesting.com/B2C2.
902 次阅读|0 个评论
[转载]SW or SF Phenomena in Internet: What Implications for NGN?
Fangjinqin 2012-12-13 09:22
Small-world or Scale-Free Phenomena in Internet: What Implications for the Next-generation Networks? Zouhaer M’Chirgui Euromed Management, LAREQUAD, Department of Information Finance Domaine de Luminy, BP 921- 13288 Marseille cedex 9, France Abstract The paper examines the large-scale topological structure of the Internet in order to see whether the structure exhibits some features that lead Internet Services Providers to go aside further collaboration for the deploymentof next-generation networks. The results indicate the existence of positive signs or early stages of possible movetowards more cooperative relationships, mainly among . These findings have implications for thenext-generation networks policy and strategy, particularly the move towards strategic alliances after the recentphase of mergers and acquisitions. Internet.pdf Keywords: Next-generation networks, Internet, Alliances, Small-world, Scale-free, Internet services providers1. Introduction
个人分类: 学术文章|2161 次阅读|0 个评论
San Francisco
jiaguangjia 2012-11-24 13:07
if you're going to san francisco be sure to wear some flowers in your hair if you're going to san francisco you're gonna meet some gentle people there for those who come to san francisco summertime will be a love-in there in the streets of san francisco gentle people with flowers in their hair all across the nation such a strange vibration people in motion there's a whole generation with a new explanation people in motion people in motion for those who come to san francisco be sure to wear some flowers in your hair if you come to san francisco summertime will be a love-in there if you come to san francisco summertime will be a love-in there 朋友最近要去San Francisco进修学习,我突然想起了上研究生时,我们外教经常给我们播放的一首曲子。今天下载后,听了听,感觉还是很好。 外教是一位因为战争而留在中国的美国老人,他在学校的家,是一座小楼,他会说一些汉语,还有两位中国孩子。 时间已经过去很久了,不知老人现在状况如何?谢谢这位留在中国而从事英语教育的老师。
2303 次阅读|0 个评论
the zebrafish as a model to study regeneration
LuWen0911 2012-8-1 13:32
From Paul Collodi The zebrafish possesses several favorable characteristics including a short generation time, external fertilization and optically clear embryos that make it an excellent model for studies involving the early stages of embryogenesis. Despite these advantages, one deficiency of the zebrafish model is the lack of methods for targeted gene inactivation and the production of knockouts. We have been working to address this problem by developing gene-targeting methods using pluripotent embryonic stem (ES) cell and primordial germ cell (PGC) lines derived from zebrafish embryos. Methods have been established for the culture of zebrafish ES cells that possess the capacity to contribute to the germ cell lineage of a host embryo. The ES cell cultures have been used to generate transgenic lines of fish and we are currently working to use the cultures to introduce targeted mutations by homologous recombination and produce zebrafish knockouts. The ES cell cultures will enhance the value of the zebrafish model for studies of gene function. http://zebrafish.org/zirc/home/guide.php
2920 次阅读|0 个评论
2012全国研究生暑期学校授课课件
热度 1 feiyou 2012-7-6 20:52
包含:Transmitters of the next generation Looking back at Microwave monolithic microwave integrated circuits 欢迎下载
3537 次阅读|6 个评论
[转载][Science June 2012] China Pushes the ‘Internet of Things’
热度 2 lhj701 2012-6-16 10:38
China Pushes the ‘Internet of Things’ The Internet of Things," which merges cloud computing with radio-frequency identification, wireless sensors, and other forms of embedded intelligence to develop the next generation of networked "smart" devices, has become a buzzword in China, giving rise to investors' guides, articles in the popular press, and a slew of dedicated websites. Experts caution that China's prowess is limited and that leading research on the Internet of Things is coming out of Europe and the United States. But with strong government support and a huge interest in new technologies, China's influence is growing in the emerging field. 详细内容: Science-2012-Hvistendahl.pdf
个人分类: 物联网|1994 次阅读|4 个评论
[转载]网格剖分Mesh Generation & Grid Generation
meigang 2012-5-24 16:42
Mesh Generation Grid Generation on the Web http://www.robertschneiders.de/meshgeneration/meshgeneration.html Gmsh: http://www.geuz.org/gmsh/
3169 次阅读|0 个评论
Public draft of next generation of ISO Schematron available
edwinuestc 2012-4-17 00:49
http://broadcast.oreilly.com/2010/04/public-draft-of-next-generatio.html The Committee Draft (CD) of the new version of ISO Schematron is now available at the ISO/IEC JTC1 SC34 SC34 Website (PDF). In the JTC1 workflow, this is the version that National Bodies comment on over the next 3 months. You can send comments in too, for example to me (as editor) or NB participants of the WG1 and SC34 (such as Alex Brown, Francis Cave, Jiří Kosek, Murata Makoto and Mohamed Zergaoui) and the issue can be raised in NB comments: I already have included features and changes based on comments here and from the Schematron mail list. After the ballot, we resolve any comments and put out a Final Draft International Standard (FDIS) (which is not open, so to reduce drag from implementations of drafts that might work against late changes, and to reduce the chance of implementations claiming to implement a standard but actually implementing a draft.) Then this FDIS gets voted on again. So it now is looking like 1Q2011 before the new version gets on the books at earliest: five years between versions seems healthy. All the features of the CD are already in the popular skeleton implementation at www.schematron.com (which I maintain) which has superceded my old Schematron 1.5 implementation at Academia Sinica. Please use ISO Schematron for new projects. I have discussed many of the new features of the draft before, but I'll just summarize some again: Modularity : The 2006 standard had anincludeelement however it was not very useful: it just stuck the external XML file and fragment inline. The 2010 CD enhances theextendselement, which substitutes the contents of the located file and fragment; this simple macro mechanism allows containers without the complication of SD-style components . Properties : The 2006 standard was most interested in communications with humans, and successful at that. It did provide several facilities for annotating this information, such as therole,seeandflagattributes. However, I began to see many users wanting incorporate structured information for automated processing in the assertion text, violating the purpose of it. For example, people would make an assertionX1233:c.34:2009:The widget should have a silly name, and then have some home-make parsing mechanism to extract the messages. This was particularly true when the structured information had some generated information. So the new properties element has been created to allow a more powerful approach with better representation of the separate concerns. The CD has a new Annex L, which gives many examples of what properties can be used for. Properties also provide a way of adding non-Schematron constraints, such as CRDL character repertoire typing. XSLT2 and EXSLT : Schematron is not limited to using XSLT1, but the schemas can select which query language binding they use. The 2006 standard reserved several names for this purpose. The two most popular are XSLT2 and EXST, so the CD defines bindings for these. (There is also an informative example binding for STX, the streaming transformations, to encourage implementation.) Structure Variables : The 2006 standard only allowed an XPath expression as the value of aletelement. However, this meant that when you wanted to have a lookup table for information, for better modularity, you had to use an reference to an external document. So the CD follows XSLT and also allows the value of a variable to be given in its content, which could include any arbitrary element content. Support for Document Collections : The advent of the XML-in-ZIP formats has brought to a head the trend in XML away from single large documents towards smaller linked documents. But this changed has reduced the utility of validation: patterns may be distributed between documents! The 2006 standard already allowed thedocument()function, which allowed an assertion or variable to access information in an external document, however the rule contexts were always the document being validated. In the CD, thepatternelement may have adocumentsattribute that can have an XPath expression that evaluates to a list of URLs. The pattern is tested on each of these documents in turn. (I am really happy with this approach, because it strengthens the idea of a pattern as something that adheres to documents rather than merely being some kind of odd type mechanism that adheres to information items.) I suppose it might even allow patterns limited to particular branches, too, but I have not pushed this as a justification, but it might have some efficiency and phase benefits. On this last feature, there is a suggestion that the mooted ISO ZIP standard should provide a simple solution to the multiple-document XML-in-ZIP validation problem: a kind of reverse structure to NVDL which creates a temporary synthetic XML document containing the ZIP directory structure and any XML files put inline: this would allow a single conventional schema to validate the whole XML-in-ZIP document even with grammars, and it would interact with NVDL well. However, thesch:pattern/@documentsattribute would be useful in any case. So please feel free to make comments on the draft, even here in the comments section. Especially if you have come to any brick walls where something that you were expecting to be simple was in fact not supported very well by the standard. The new draft Schematron standard is now a massive 40 pages. My expectation is that the standard will continue to be available free from ISO. Pretty good bang per buck. (Special thanks to WG1 convenor Alex Brown for the typesetting.)
个人分类: 程序调试|2082 次阅读|0 个评论
[转载]Give the new generation a chance (zt)
热度 2 stoneblue 2012-1-12 10:00
http://www.nature.com/news/2011/110629/full/474543a.html Give the new generation a chance Romain Murenzi wants more young scientists in the developing world to be given the same opportunity to build careers that he was. Romain Murenzi In 1982, I was a 23-year-old high-school teacher recently graduated in mathematics from the National University of Burundi, but I dreamt of earning a PhD in mathematics and physics and a professorship at a major university. I applied for a 'Bourse du Tiers Monde' from the Catholic University of Louvain in Belgium, but was rejected. One reviewer said: "He is a refugee from Rwanda. If he comes to Europe for a PhD he will never return. Africa will lose an excellent high-school teacher." The response was both complimentary and inadvertently dismissive, suggesting that both I and Africa would be better off if I stayed put. I applied again the following year, and was selected. Since then, I have held various university and research posts in both Europe and the United States, and from 2001 to 2009 I had the honour to serve as minister of education, science and technology of Rwanda. I have been thinking about my personal journey lately. In April, I became executive director of TWAS, the academy of sciences for the developing world. The academy, which is administered by the United Nations Educational, Scientific and Cultural Organization and funded by the Italian government, is dedicated to building scientific capacity and excellence in developing countries. Part of the TWAS mission is to address the needs of young scientists. And although I hesitate to draw general conclusions from an individual case, this tempts me to compare my own experience (and those of my colleagues a generation ago) with the situation today. First the good news. It is highly unlikely that reviewers would suggest a promising fellowship applicant should not move. Brain drain is now seen as best addressed without compromising an individual's desire to reach his or her full potential. Also, there are many postgraduate and postdoctoral programmes, increasingly based on collaboration between the traditionally poorer countries of the Southern Hemisphere. TWAS alone offers more than 300 fellowships each year, sponsored by Brazil, China, India, Kenya, Malaysia, Mexico, Pakistan and Thailand. But we cannot close our eyes to aspects of science in the developing world that have not changed fast enough. First, there is the growing gap between countries that are rapidly strengthening their scientific capacity and those that lag behind. Just six developing countries account for three-quarters of the scientific articles published by scientists from the developing world in international peer-reviewed journals. And China alone accounts for 30% of all papers by scientists in the developing world. Clearly, such imbalances have serious implications for scientists — and especially for young scientists — in countries that are failing to keep pace. Second, even for countries in which scientific capacity is growing, there remains a yawning gap between science and innovation. This has particularly serious implications for poor developing countries, where politicians need to regard sustained investment in science as a way of reducing poverty and increasing wealth. “We cannot close our eyes to aspects of science in the developing world that have not changed fast enough.” I believe that three major steps must be taken to help countries stymied by poor scientific and economic capacity. First, provide adequate training for the next generation of developing-world scientists. Without a critical mass of professors with PhDs, and doctorate-level research, there is no way that scientific capacity can be built, let alone flourish. Second, expand opportunities for scientific exchange with colleagues in technologically advanced countries. Growing numbers of fellowships are available, yet the total number remains small. Too many eager and able young scientists in developing countries continue to be denied opportunities. And third, young scientists from developing countries must be given broader opportunities to obtain research funds to continue their studies. Again, levels of funding are increasing, but not rapidly enough to meet the growing demand. Part of this funding can be derived from foreign donors, but part must come from the countries themselves. Rwanda spends 1.6% of its gross domestic product on science and technology. This benefits a wide range of institutions, including the National University of Rwanda in Butare and the Kigali Health Institute. To boost tertiary education in science even further, 70% of the loans available for higher education are reserved for students majoring in disciplines related to science and technology. Furthermore, Rwanda's efforts have drawn help from governments and funding agencies from across the globe. Global financial institutions and bilateral development agencies must devise more comprehensive strategies to integrate science and technology into their development efforts. And the governments of scientifically lagging countries must create and pursue policies centred on long-term capacity building in science, technology and innovation. With most of the world's young people coming from the developing world, the future of not just poor countries but the entire world will depend on support for its young scientists. It is vital that university graduates there are given the same opportunity that I was. Romain Murenzi is the executive director ofTWAS, the academy of sciences for the developing world, inTrieste,Italy.
286 次阅读|2 个评论
[转载]Reactive Magnetron Sputtering
xpzhanghit 2011-12-29 20:50
Dr Stijn Mahieu Ghent University Archived topic page last updated on 16 July 2008 http://www.scitopics.com/Reactive_Magnetron_Sputtering.html Magnetron sputtering is a widely used PVD (Physical Vapour Deposition) technique to deposit thin films. This technique is based on the generation of a magnetically enhanced glow discharge , the so-called magnetron discharge . When a reactive gas is added to the discharge, it becomes possible to deposit compound materials. This process, i.e. reactive sputter deposition, has been recently reviewed in two papers . Both papers discuss in detail the reactive sputter process and its stability problems . Indeed, the addition of the reactive gas results not only in the formation of a compound on the substrate but also on the target or cathode surface . This can result in a sudden decrease of the deposition rate and an abrupt change in the partial pressure of the reactive gas , the so-called hysteresis or poisoning effect . Although both papers give an excellent overview of the reactive sputter process and the techniques to circumvent the hysteresis effect , recent experimental and modelling results show that several fundamental aspects concerning reactive sputtering have not been elucidated yet. One of the major problems of the reactive sputter process is its complexity . Indeed, to understand and describe this deposition process in all its details, a complete characterisation and description of the sputter process is necessary. More specific, the interaction between target processes , plasma processes , the sputter process and subsequent collisional transport of the sputtered particles through the gas phase and all substrate processes should be taken into account since all of them are related to each other. Attempts to obtain such a total description of the sputter process are ongoing in or research group . A good understanding of the reactive sputtering process is essential when tailoring the thin film properties. Indeed, several authors have shown that the plasma chemistry plays a crucial role in the development of the microstructure and the crystallographic orientation of the deposited thin films . It is beyond doubt that the crystallographic orientation and the microstructure influence a wide variety of thin film properties. For “simple” materials these relationships have been thoroughly examined. However, most of the new technological interesting materials have a complex chemical (and crystalline) structure . These multi-elemental materials allow to tune many parameters, including lattice constants, electronic band structures, and magnetic properties. References * W.D. Westwood, Sputter Deposition, AVS Education Committee Books Series, Volume 2, AVS (New York) 2003 (ISBN 0-7354-0105-5) * “Fundamental understanding and modeling of reactive sputtering processes” S. Berg, T. Nyberg, Thin Solid Films 476 (2005) 215-230 * “Control of reactive sputtering processes” W.D. Sproul, D.J. Christie, D.C. Carter, Thin Solid Films 491 (2005) 1-17 * “Target poisoning during reactive magnetron sputtering: Part I: the influence of ion implantation” D. Depla, R. De Gryse, Surf. Coat. Technol. 183 (2004) 184-189 (Link-) * “Modeling of the target surface modification by reactive ion implantation during magnetron sputtering” D. Depla D, Z.Y. Chen, A. Bogaerts, V. Ignatova, R. De Gryse, R. Gijbels, J. Vac. Sci. Technol. A22 (2004) 1524-1529 (Link-) *“Comprehensive perspective on the mechanism of preferred orientation in reactive- sputter-deposited nitrides” Y. Kajikawa, S. Noda, H.Komiyama, J. Vac. Sci. Technol. A 21 (2003) 1943-1959 * “Mechanism of preferential orientation in sputter deposited titanium nitride and yttria- stabilized zirconia layers” S. Mahieu, P. Ghekiere, G. De Winter, S. Heirwegh, D. Depla, R. De Gryse, O.I. Lebedev, G. Van Tendeloo, J. Cryst. Growth 279 (2005) 100-109 (Link-) * "Reactive Sputter Deposition" edited by D. Depla and S. Mahieu, Springer, 978-3540766629 (Link-) * "Biaxial alignment in sputter deposited thin films" S. Mahieu, P. Ghekiere, D. Depla, R. De Gryse, Thin Solid Films 515 (2006) 1229 (Link-)
个人分类: 网文精短|9 次阅读|0 个评论
[转载]二代测序技术
cmcheng 2011-11-17 16:02
高通量测序技术是对传统测序一次革命性的改变,一次对几十万到几百万条DNA分子进行序列测定,因此在有些文献中称其为下一代测序技术 (next generation sequencing)足见其划时代的改变,同时高通量测序使得对一个物种的转录组和基因组进行细致全貌的分析成为可能,所以又被称为深度测序(deep sequencing)。 自从2005年454LifeSciences公司(2007年该公司被Roche正式收购)推出了 454FLX焦磷酸测序平台(454FLXpyrosequencingplatform)以来,曾推出过3730xl DNA测序仪 (3730xlDNAAnalyzer) 的Applied BioSystem(ABI)这家一直占据着测序市场最大份额的公司的领先地位就开始动摇了,因为他们的拳头产品毛细管阵列电泳测序仪系列 (seriescapillaryarrayelectrophoresissequencingmachines)遇到了两个强有力的竞争对 手,一个就是罗氏公司(Roche)的454 测序仪(Roch GS FLX sequencer),,另一个就是2006年美国Illumina公司推出的Solexa基因组分析平台(GenomeAnalyzer platform),为此,2007年ABI公司推出了自主研发的SOLiD 测序仪(ABI SOLiD sequencer)。这三个测序平台即为目前高通量测序平台的代表。(见表一) 公司名称 技术原理 技术开发者 商业模式 Apply Biosystems(ABI) 基于磁珠的大规模并行克隆连接DNA测序法 美国Agencourt私人基因组学公司(APG) 上市公司: 销售设备和试剂获取利润 Illumina 合成测序法 英国Solexa公司首席科学家David Bentley 上市公司: 销售设备和试剂获取利润 Roche 大规模并行焦磷酸合成测序法 美国454 Life Sciences公司的创始人Jonathan Rothberg 上市公司: 销售设备和试剂获取利润 Helicos 大规模并行单分子合成测序法 美国斯坦福大学生物工程学家Stephen Quake 上市公司:2007年5月首次公开募股(IPO) Complete Genomics DNA纳米阵列与组合探针锚定连接测序法 美国Complete Genomics公司首席科学家radoje drmanac 私人公司:投资额为4650万美元 表一:主流测序平台一览 这些平台共同的特点是极高的测序通量,相对于传统测序的96道毛细管测序,高通量测序一次实验可以读取40万到 400万条序列。读取长度根据平台不同从25bp到450bp,不同的测序平台在一次实验中,可以读取1G到14G不等的碱基数,这样庞大的测序能力是传 统测序仪所不能比拟的。尽管如此,在这项新的划时代的测序技术刚出现的时候,科学界对这项新技术却并不热衷。许多习惯用桑格技术的科学家怀疑新技术的准确 度、阅读能力、成本消费、实用性。代理Sanger型测序硬件的经销商害怕其投资失败而首先提出了这些怀疑。 图一:在芯片上进行的测序:Illumina测序平台 然而大多数人却忽略了一个事实,即桑格技术的普及最初也遇到同样的阻碍。桑格技术刚开发出来时,阅读能力很难超过 25bp,即使在Fred Sanger双脱氧终止法发明后也只达到80bp,如今却达到了750bp;而新发展的合成测序技术,应用焦磷酸测序方法,其阅读能力最初只有 100bp,推向市场16个月后增加至250bp,随着技术的不断完善,目前已达到了400bp,很快就接近桑格技术目前的水平。除了阅读能力外,能否以 有限的成本用一台仪器产生足够数量的序列标记也是另一个需要改善的重要问题。这个问题已经被Roche公司解决了,应用他们的系统,仅花费阅读35bp或 者更小片段的成本就能产生比35bp多10倍的序列标记。 图二:GS FLX 高通量测序方法原理示意图 一、高通量测序的应用 高通量测序可以帮助研究者跨过文库构建这一实验步骤,避免了亚克隆过程中引入的偏差。 依靠后期强大的生物信息学分析能力,对照一个参比基因组(reference genome)高通量测序技术可以非常轻松完成基因组重测序(re-sequence),2007年van Orsouw等人结合改进的AFLP 技术和454 测序技术对玉米基因组进行了重测序,该重测序实验发现的超过75%的SNP位点能够用SNPWave技术验证,提供了一条对复杂基因组特别是含有高度重复 序列的植物基因组进行多态性分析的技术路线。2008年Hillier对线虫CB4858 品系进行Solexa重测序,寻找线虫基因组中的SNP位点和单位点的缺失或扩增。但是也应该看到,由于高通量测序读取长度的限制,使其在对未知基因组进 行从头测序(novo sequencing)的应用受到限制,这部分工作仍然需要传统测序(读取长度达到850 碱基)的协助。但是这并不影响高通量测序技术在全基因组mRNA表达谱,microRNA表达谱,ChIP-chip以及DNA甲基化等方面的应用。 2008年Mortazavi等人对小鼠的大脑、肝脏和骨骼肌进行了RNA 深度测序,这项工作展示了深度测序在转录组研究上的两大进展,表达计数和序列分析。对测得的每条序列进行计数获得每个特定转录本的表达量,是一种数码化的 表达谱检测,能检测到丰度非常低的转录本。分析测得的序列,有大于90%的数据显示落在已知的外显子中,而那些在已知序列之外的信息通过数据分析展示的是 从未被报道过的RNA剪切形式,3’端非翻译区,变动的启动子区域以及潜在的小RNA 前体,发现至少有3500个基因拥有不止一种剪切形式。而这些信息无论使用芯片技术还是SAGE文库测序都是无法被发现的。 高通量测序另一个被广泛应用的领域是小分子RNA或非编码RNA(ncRNA)研究。测序方法能轻易的解决芯片技术在检测小分子时遇到的技术难 题(短序列,高度同源), 而且小分子RNA的短序列正好配合了高通量测序的长度,使得数据“不浪费”,同时测序方法还能在实验中发现新的小分子RNA。在衣藻、斑马鱼、果蝇、线 虫、人和黑猩猩中都已经成功地找到了新的小分子RNA。在线虫中获得了40 万个序列,通过分析发现了18个新的小RNA分子和一类全新的小分子RNA。 在DNA—蛋白质相互作用的研究上,染色质免疫沉淀—深度测序(ChIP-seq)实验也展示了其非常大的潜力。染色质免疫沉淀以后的DNA 直接进行测序,对比ref seq可以直接获得蛋白与DNA结合的位点信息,相比ChIP-chip,ChIP-seq可以检测更小的结合区段、未知的结合位点、结合位点内的突变情 况和蛋白亲合力较低的区段。 图三: Independent Flow Cells(SoLid TM System) 二、高通量测序的前景 目前,大多分析家都无法相信新一代测序技术能完全取代目前的芯片测序技术。不过,有些分析家也的确认为芯片测序技术正面临着挑战,他们认为到了2012年新一代的测序技术将会带来高达2。15亿美元的产值。 2006年,整个芯片测序市场大概价值8亿美元,其中65%的市场份额都是有关基因表达谱分析产品的,剩下35%的市场份额则由基因型分析芯片 占据。不过美国哈佛大学(HarvardUniversity)遗传学教授George Church认为,这部分市场也会受到新一代测序技术的冲击。重测序芯片(resequencingarrays)、单 核苷酸 多态性分析芯片以及基因拷贝数目变异分析芯(copynumbervariantarray)市场也会受到影响。也有分析家不赞同这个观点,他们认为即使新一代测序技术很便宜,还是有不少人会选择传统的测序仪的。 新一代测序技术相对传统芯片测序技术的优势,最终还得依靠广告和市场营销手段的推广才能获得大众的认可。去年夏天,由 FrostSullivan公司对学术科研机构和私人研究团体进行的一项调查研究结果表明,在实际应用领域,例如进行表达谱分析时,人们还 是倾向于选择传统的芯片产品,而并非青睐新一代的测序产品。 新一代测序仪推广困难可能由其价格昂贵导致。平均采购一台新一代测序仪大约要花费50万美元,除非该实验室测序的工作量非常大,否则是不会考虑 购买的。即使像Polonator这样的新一代测序仪也需要花费15万美元左右,这笔费用对于一个小实验室来说是无法承受的。这时,只需要150美元一块 的芯片就非常有竞争力了。以基因芯片产品享誉业界的美国Affymetrix公司市场部副总裁Jay Kaufman认为,新一代测序技术对于芯片市场来说的确会带来一定的冲击,不过要完全取代表达谱分析芯片还需要一定的时间。 但是,基因芯片也有其自身的缺点,就在于它是一个“封闭系统”,它只能检测人们已知序列的特征(或有限的变异)。而高通量测序的强项, 就在于它是一个“开放系统”, 它的发现能力和寻找新的信息的能力,从本质上高于芯片技术。 研究者可以充分享受这两个平台的比较优势,在获取新信息的基础上,利用芯片的强项, 即对已知信息的高通量、低成本(相对)的检测能力, 对大量样品进行快速检测,短时间内获得有大量有效的数据。 作为两个高通量的基因组学研究技术,在应用的某些方面存在重叠和竞争,但是在更多方面是优势互补,两种方法联合使用,将解决以前的单种技术难以解决的问题。 三、结语 新一代测序已显示出巨大的潜力。也正是因为科学的不断进步,在给测序技术提出新要求的时候,也给这项技术带来了新的增长点: 2008年4月Helico BioScience公司的Timothy等人在Science上报道了他们开发的真正的单分子测序技术,也被称为第三代测序技术,并利用该技术对一个 M13病毒基因组进行重测序。这项技术之所以被称为真正的单分子测序,是因为它完全跨过了上述3种高通量测序依赖的基于PCR扩增的信号放大过程,真正达 到了读取单个荧光分子的能力,向1000美元测定一个人类基因组的目标迈出了一大步。
个人分类: 测序|4902 次阅读|0 个评论
Beyond Local Appearance 的学习笔记
allendd 2010-11-22 23:09
《Beyond Local Appearance: Category Recognition from Pairwise Interactions of Simple Features》
个人分类: 科研学习|44 次阅读|0 个评论
Chinese and American Young Generation Confront a Same World
baoyu 2010-11-17 19:58
Chinese and American Young Generation Confront a Same World by Yubao   The world Chinese young generation faced is different from Americans? It is a little complicated to answer this question. I think there is no great difference there and on the contrary there is a tendency of convergence such as re-education trend, career desperation and reality unintelligent.   Like most college graduate come back to school in the United States , Chinese graduates are coming with the same tide. While some of the college graduates just continued to pursuit a Ph. D degree. Maybe the young generation of America has more working experience, for they start work earlier and changing work more frequently. But we can see a tide of returning to Graduate school after the Financial Crisis. UnlikeRoger Bacon said at three hundred yours ago, scientia potentia est (Knowledge is power), the line between power and knowledge is becoming more and more indistinct. Ph. D is no more a guarantee to a decent job.   Many young men do not have a clear expectation of their career development. You can find the same thing in America . As many Scenes in the film Sex and the City, Greens Anatomy and Gossip Girl, are considered as a reflection of job seeking, city living in USA . Interestingly you can discover the counterpart in Chinese films, like Du Lalas promotion, Hard Working. They present snapshots of harsh reality the Chinese young generation faced.   More and more people lost a solid cognition to the realty and honesty sprits to themselves. Two decade years ago, young people would read classic literature, care about the democracy, pay attention to social issues, but all these things are just kept in middle ages memory and faint away in the 21 century. Now we just read bills and only care about money and pleasure. It is a hard thing to inspect and comfort the inside of our own. So we easily surrender to the fancy world without a thinking and cheaply traffic ourselves in the labor market. Many intellectuals think this is the root of all evil in the world.   We confront a flat world and it makes people lost destination, struggling for survival in the Postmodernism time. It is reliable to meet someone in the other side of the Earth, but we are tightly confined in a network knitted by commodities and markets. Sooner or later, the old clich, the vast pacific and social ideologies are the boundaries between China and United states , will be replaced by a new topic as rising young generation in the same Arena.
个人分类: 未分类|6013 次阅读|0 个评论
49, 3D mesh generation
weihuayi 2010-9-5 15:49
49.1 Introduction 这个软件包主要用于生成各向同性四面体网格,来离散三维区域; 两个主要功能: 生成和细分; 区域可以是单连通区域,也可以是多连通区域 Input domain pure 3D complex? A: 与其相对应的是 simplex, 也许可以分别译为:单纯形 和 复合形。 3D complex is pure, 意思是每一个face(0d,1d,2d,3d)都包含在至少一个3d的face中。 所以complex 可以描述为3D单元的集合。 the difference of face and facet? A: face 包括 vertices(0), edges(1), facets(2) 和 cells(3) 目前可以处理: implicit functions, polyhedral domains, and domains defined through 3D labeled images. Output Mesh 区域的每个曲面片或者子区域的边界是由Delaunay facets的集合来逼近, 这些Delaunay facets的对偶Voronoi edge和曲面片相交。 这些facets 被称为 Surface facets or boundary facets. Delaunay refinement 网格生成算法 是由一个Delaunay refinement process, 再加上一个优化组成。 网格生成准则。 Surface facet: 1, the angular bound. 2, the radius bound. 3, the distance bound. Mesh cell: 1, the radius-edge bound. 2, the radius bound. Optimization phase a Lloyd smoothing, an odt-smoothing, a perturber and an exuder. 四种优化方法的调用顺序: odt-smoother, Lloyd-smoother, perturber, exuder 49.2 Interface template class C3T3, class MeshDomain, class MeshCriteria C3T3 make_mesh_3( MeshDomain domain, MeshCriteria criteria, parameters::internal::Lloyd lloyd = parameters::no lloyd(), parameters::internal::Odt odt = parameters::no odt(), parameters::internal::Perturb perturb = parameters::perturb(), parameters::internal::Exude exude = parameters::exude()) template class C3T3, class MeshDomain, class MeshCriteria void refine_mesh_3( C3T3 c3t3, MeshDomain domain, MeshCriteria criteria, parameters::internal::Lloyd lloyd = parameters::no lloyd(), parameters::internal::Odt odt = parameters::no odt(), parameters::internal::Perturb perturb = parameters::perturb(), parameters::internal::Exude exude = parameters::exude()) The function make_mesh_3 generates from scratch a mesh of the input domain, while the function refine_mesh_3 refines an existing mesh of the input domain. LabeledImage_3 CGAL::lloyd_optimize_mesh_3 #include CGAL/lloyd optimize mesh 3.h templatetypename C3T3, typename MeshDomain Mesh optimization return code lloyd optimize mesh 3( C3T3 c3t3, MeshDomain domain, double time limit=0, std::size t max iteration number=0, double convergence=0.02, double freeze bound = 0.01) Precondition: time limit 0 and 0 convergence 1 and 0 freeze bound 1 CGAL::make_mesh_3 The vertex and cell base classes of the triangulation C3T3::Triangulation are required to be models of the concepts MeshVertexBase_3 and MeshCellBase_3 respectively. class--model---concept , 怎样去理解这个关系? concept 是用来描述一个数据类型的要求的, 它有如下的方面: 0, Definition: 定义 1, Refine : 是某个其它概念的细化 2,Types:它拥有的数据类型 3,Operations: 它拥有的操作 4,Internal: 中间操作,不鼓励用户使用,可能会改变。 5,Has Models: 拥有的Models class是类 Definiton: Parameters: 模板参数 Is Model for the Concepts: 是某个概念的Model Types: 拥有的数据类型 Inherits From: 继承自 Creation: 如何创建 Operation: 操作
个人分类: 生活|4407 次阅读|0 个评论
[转载]LOST GENERATION, NOT (upside-down reading)
zuojun 2010-4-15 15:29
It's worth watching, especially for those who were born in the 1980s. http://www.youtube.com/watch_popup?v=42E2fAWM6rA By Jonathan Reed If you cannot watch YouTube, try this site, which shows the writing (but I am unable to steal): http://www.killahbeez.com/2009/01/23/lost-generation/ If you still cannot read it, here it is. (I typed it myself; any typos?) I am part of the Lost Generation And I refuse to believe that I can change the world I realize this may be a shock but Happiness comes from within Is a lie, and Money will make me happy So in 30 years I will tell my children They are not the most important thing in my life My employer will know that I have my priorities straight because Work Is more important than Family I tell you this once upon a time families stayed together but this will not be true in my era this is a quick fix society experts tell me 30 years from now I will be celebrating the 10th anniversary of my divorce I do not concede that I will live in a country of my own making In the future Environmental destruction will be the norm No longer can it be said that My peers and I care about this Earth It will be evident that my generation will be apathetic and lethargic it is foolish to presume that There is hope. And all of this will come true unless we choose to reverse it. (Then you read backward...) Note: This concept is based on a political advertisement by Recrear, which you can view at http://www.youtube.com/watch?gl=CAhl=env=lFz5jbUfJbk or read what I copied down at http://www.sciencenet.cn/m/user_content.aspx?id=312537
个人分类: From the U.S.|2654 次阅读|1 个评论

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