当前共找到 1276 篇文献分享,本页显示第 841 - 860 篇。
841.
小W
(2022-10-31 22:14):
#paper doi:https://doi.org/10.1038/s42255-022-00636-3 Metabolic collateral lethal target identification reveals MTHFD2 paralogue dependency in ovarian cancer 基因组结构改变导致肿瘤抑制基因功能缺失失活,是肿瘤发生的重要驱动因素。这些缺失为癌细胞提供了功能和适应性优势,但由于邻近染色体中的必要基因的缺失,为了避免癌细胞死亡,这些细胞会找到一种具有类似功能的基因以保持细胞存活。本文作者设计了一个集成的工作流程(CLIM),利用癌症患者(TCGA)的基因组和转录组学特征来识别代谢基因缺失,重建基因组规模代谢模型(GSMMs),进行基于细胞目标的代谢通量分析,来揭示副致死靶向的代偿代谢途径。通过抑制副致死靶向的代偿代谢途径,达到精准杀死肿瘤细胞的目的。通过该算法,该团队成功在高级别浆液性卵巢癌(HGSOC)中 预测出 伴随 19p13.3 缺失 的代谢基因 UQCR11 及其 旁系途径 MTHFD2。实验部分通过示踪剂动态追踪实验、UQCR11/MTHFD2 缺失细胞代谢变化、 MTHFD2 基因是否敲除 的19p13.3 肿瘤小鼠模型的肿瘤生长等实验验证了预测的副致死靶点的有效性。
Abstract:
Recurrent loss-of-function deletions cause frequent inactivation of tumour suppressor genes but often also involve the collateral deletion of essential genes in chromosomal proximity, engendering dependence on paralogues that maintain similar …
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Recurrent loss-of-function deletions cause frequent inactivation of tumour suppressor genes but often also involve the collateral deletion of essential genes in chromosomal proximity, engendering dependence on paralogues that maintain similar function. Although these paralogues are attractive anticancer targets, no methodology exists to uncover such collateral lethal genes. Here we report a framework for collateral lethal gene identification via metabolic fluxes, CLIM, and use it to reveal MTHFD2 as a collateral lethal gene in UQCR11-deleted ovarian tumours. We show that MTHFD2 has a non-canonical oxidative function to provide mitochondrial NAD, and demonstrate the regulation of systemic metabolic activity by the paralogue metabolic pathway maintaining metabolic flux compensation. This UQCR11-MTHFD2 collateral lethality is confirmed in vivo, with MTHFD2 inhibition leading to complete remission of UQCR11-deleted ovarian tumours. Using CLIM's machine learning and genome-scale metabolic flux analysis, we elucidate the broad efficacy of targeting MTHFD2 despite distinct cancer genetic profiles co-occurring with UQCR11 deletion and irrespective of stromal compositions of tumours.
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842.
cellsarts
(2022-10-31 22:09):
#PaperDOI: 10.2217/fmb.12.61阴沟肠杆菌复合体:临床影响和新出现的抗生素耐药性Enterobacter cloacae complex: Clinical impact and emerging antibiotic resistance
July 2012Future Microbiology 7(7):887-902阴沟肠杆菌复合体的种类在自然界中广泛存在,但它们可以作为病原体。阴沟肠杆菌的生物化学和分子研究显示出基因组的异质性,包括 Enterobacter cloacae/ 阴沟肠杆菌 , Enterobacter asburiae/ 阿斯帛肠杆菌 , Enterobacter hormaechei/霍马埃希肠杆菌, Enterobacter kobei/ 哥贝肠杆菌, Enterobacter ludwigii/路德维希肠杆菌、 and Enterobacter nimipressuralis/ 米克雷肠杆菌 肠杆菌6种,其中阴沟肠杆菌和霍马埃希肠杆菌是人类临床标本中分离最频繁的两种。对属于这个分类单元的所有物种进行表型鉴定通常是困难的,而且并不总是可靠的;因此,分子生物学方法经常被使用。尽管阴沟肠杆菌复合菌株是过去十年中最常见的引起医院血流感染的肠杆菌属,但对其毒性相关特性知之甚少。相比之下,关于这些微生物的耐药特征已经发表了很多文章。事实上,它们能够通过对染色体基因的去抑制或在质粒上获得可转移的AmpC基因而产生过量的AmpC β-内酰胺酶。最近获得了许多其他的耐药决定因素,这些决定因素可以使几乎所有抗生素家族失效。对阴沟肠杆菌、霍氏肠杆菌和阿氏肠杆菌的药敏研究较多;这些研究报告了物种之间的微小差异,唯一显著的差异没有区分特征。
Abstract:
Species of the Enterobacter cloacae complex are widely encountered in nature, but they can act as pathogens. The biochemical and molecular studies on E. cloacae have shown genomic heterogeneity, comprising …
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Species of the Enterobacter cloacae complex are widely encountered in nature, but they can act as pathogens. The biochemical and molecular studies on E. cloacae have shown genomic heterogeneity, comprising six species: Enterobacter cloacae, Enterobacter asburiae, Enterobacter hormaechei, Enterobacter kobei, Enterobacter ludwigii and Enterobacter nimipressuralis, E. cloacae and E. hormaechei are the most frequently isolated in human clinical specimens. Phenotypic identification of all species belonging to this taxon is usually difficult and not always reliable; therefore, molecular methods are often used. Although the E. cloacae complex strains are among the most common Enterobacter spp. causing nosocomial bloodstream infections in the last decade, little is known about their virulence-associated properties. By contrast, much has been published on the antibiotic-resistance features of these microorganisms. In fact, they are capable of overproducing AmpC β-lactamases by derepression of a chromosomal gene or by the acquisition of a transferable ampC gene on plasmids conferring the antibiotic resistance. Many other resistance determinants that are able to render ineffective almost all antibiotic families have been recently acquired. Most studies on antimicrobial susceptibility are focused on E. cloacae, E. hormaechei and E. asburiae; these studies reported small variations between the species, and the only significant differences had no discriminating features.
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843.
小年
(2022-10-31 21:19):
#paper doi:10.1016/j.gpb.2022.09.004. ncFO: A Comprehensive Resource of Curated and Predicted ncRNAs Associated with Ferroptosis. Genomics Proteomics Bioinformatics. 2022.
细胞死亡在组织发育和体内平衡中起关键作用,并抑制癌细胞的过度增殖。铁死亡是由脂质过氧化诱导的一种特殊类型的调节性细胞死亡方式,探索铁死亡的潜在调节因子将有助于阐明其分子机制和仔细研究潜在的药物靶点。
目前虽然有铁死亡与疾病关联的调节剂和标志物数据库FerrD,但不便于研究人员对铁死亡相关非编码RNA(ncRNA,包括miRNA、lncRNA、circRNA)进行系统研究,ncRNA已被证实参与铁死亡的调节,文献中的信息不方便研究人员从综合角度表征铁死亡相关的ncRNA。为了填补这一空白,作者开发了ncRNA-铁死亡关联数据库(ncFO, http://www.jianglab.cn/ncFO/),ncFO是第一个收集了实验验证的铁死亡相关ncRNA并预测候选ncRNA-铁死亡关联的平台。用户可以获得经过实验验证的ncRNA-铁死亡关联,包括ncRNA名称、疾病、物种、组织、靶标、调控、发表时间和PMID。此外,ncFO数据库还提供了ncRNA的生存分析和差异表达分析。数据库为查询和分析铁死亡相关的ncRNA提供可靠的分析平台,为癌症治疗靶点的识别提供参考。
Abstract:
Ferroptosis is a form of regulated cell death driven by the accumulation of lipid hydroperoxides. Regulation of ferroptosis might be beneficial to cancer treatment. Non-coding RNAs (ncRNAs) are a class …
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Ferroptosis is a form of regulated cell death driven by the accumulation of lipid hydroperoxides. Regulation of ferroptosis might be beneficial to cancer treatment. Non-coding RNAs (ncRNAs) are a class of RNA transcripts that generally cannot encode proteins and have been demonstrated to play critical roles in regulating ferroptosis. Herein, we developed ncFO, the ncRNA-ferroptosis association database, to document the manually curated and predicted ncRNAs that are associated with ferroptosis. Collectively, ncFO contains 90 experimentally verified entries, including 46 microRNAs (miRNAs), 21 long non-coding RNAs (lncRNAs), and 17 circular RNAs (circRNAs). In addition, ncFO also incorporates two online prediction tools based on the regulation and co-expression of ncRNA and ferroptosis genes. Using default parameters, we obtained 3260 predicted entries, including 598 miRNAs and 178 lncRNAs, by regulation, as well as 2,592,661 predicted entries, including 967 miRNAs and 9632 lncRNAs, by ncRNA-ferroptosis gene co-expression in more than 8000 samples across 20 cancer types. The detailed information of each entry includes ncRNA name, disease, species, tissue, target, regulation, publication time, and PubMed identifier. ncFO also provides survival analysis and differential expression analysis for ncRNAs. In summary, ncFO offers a user-friendly platform to search and predict ferroptosis-associated ncRNAs, which might facilitate research on ferroptosis and discover potential targets for cancer treatment. ncFO can be accessed at http://www.jianglab.cn/ncFO/.
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844.
半面阳光
(2022-10-31 19:53):
#paper DOI: 10.1038/s41436-019-0686-8, 2019, Technical standards for the interpretation and reporting of constitutional copy-number variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics (ACMG) and the Clinical Genome Resource (ClinGen). 这篇文献是ACMG和ClinGen发布的关于临床上拷贝数变异(CNVs)检测结果解读的指南。过去十几年中染色体芯片chromosomal microarray(CMA)技术已被广泛用于拷贝数变异检测,近年来基于二代测序(NGS)的CNV-Seq技术也被越来越广泛地应用于临床染色体拷贝数变异检测中。大部分检出的CNVs是独特的,需要进一步对其致病性进行评估。准确地进行临床CNVs致病性解读至关重要,并且需要一个标准化的解读方法和流程,来确保不同实验室之间解读的一致性。这篇指南首先确定了可用于对CNVs进行分类的证据类型,包括:基因组成分、剂量敏感性预测和梳理、预测功能效应、与临床文献报道病例的重叠与否、病例与对照数据库证据、以及个体CNVs的遗传模式。接着对这些不同类型的证据分配的不同的权重,最后形成了一个半定量的计分系统。这篇指南对这个评分系统的形成过程、各个记分点的说明、记分系统的使用、以及应用举例进行了详细的阐释。这一指南是目前国内外进行CNVs解读的主要参考文献。读这篇文章的体会有二,一是信息量极大,需要反复详细阅读;二是需要配合案例实际操作,才能充分理解。
IF:6.600Q1
Genetics in medicine : official journal of the American College of Medical Genetics,
2020-02.
DOI: 10.1038/s41436-019-0686-8
PMID: 31690835
Abstract:
PURPOSE: Copy-number analysis to detect disease-causing losses and gains across the genome is recommended for the evaluation of individuals with neurodevelopmental disorders and/or multiple congenital anomalies, as well as for …
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PURPOSE: Copy-number analysis to detect disease-causing losses and gains across the genome is recommended for the evaluation of individuals with neurodevelopmental disorders and/or multiple congenital anomalies, as well as for fetuses with ultrasound abnormalities. In the decade that this analysis has been in widespread clinical use, tremendous strides have been made in understanding the effects of copy-number variants (CNVs) in both affected individuals and the general population. However, continued broad implementation of array and next-generation sequencing-based technologies will expand the types of CNVs encountered in the clinical setting, as well as our understanding of their impact on human health.METHODS: To assist clinical laboratories in the classification and reporting of CNVs, irrespective of the technology used to identify them, the American College of Medical Genetics and Genomics has developed the following professional standards in collaboration with the National Institutes of Health (NIH)-funded Clinical Genome Resource (ClinGen) project.RESULTS: This update introduces a quantitative, evidence-based scoring framework; encourages the implementation of the five-tier classification system widely used in sequence variant classification; and recommends "uncoupling" the evidence-based classification of a variant from its potential implications for a particular individual.CONCLUSION: These professional standards will guide the evaluation of constitutional CNVs and encourage consistency and transparency across clinical laboratories.
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845.
xh
(2022-10-31 18:25):
#paper Applying CRISPR/Cas for genome engineering in plants: the best is yet to come https://doi.org/10.1016/j.pbi.2016.11.011文章介绍了crispr/cas9的两种方法同源重组(HR)和非同源末端连接(NHEJ)
Abstract:
Less than 5 years ago the CRISPR/Cas nuclease was first introduced into eukaryotes, shortly becoming the most efficient and widely used tool for genome engineering. For plants, efforts were centred …
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Less than 5 years ago the CRISPR/Cas nuclease was first introduced into eukaryotes, shortly becoming the most efficient and widely used tool for genome engineering. For plants, efforts were centred on obtaining heritable changes in most transformable crop species by inducing mutations into open reading frames of interest, via non-homologous end joining. Now it is important to take the next steps and further develop the technology to reach its full potential. For breeding, besides using DNA-free editing and avoiding off target effects, it will be desirable to apply the system for the mutation of regulatory elements and for more complex genome rearrangements. Targeting enzymatic activities, like transcriptional regulators or DNA modifying enzymes, will be important for plant biology in the future.
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846.
na na na
(2022-10-31 18:03):
#paper Big data in basic and translational cancer research doi: 10.1038/s41568-022-00502-0. Epub 2022 Sep 5,https://www.nature.com/articles/s41568-022-00502-0;分享一篇肿瘤大数据综述文章;在肿瘤领域,其研究焦点通常是关注肿瘤相关的生物途径和基因的突变/表达特征等,并和临床相结合进行转化;近年来,随着高通量技术的突破,大规模癌症组学数据的快速积累,研究者们或基于研究课题方向,或基于组学信息,或基于课题组资源,整理和构建了多个公共数据库,从而更好的通过公共资源以支持更多研究者的工作。本文回顾了通过大数据来推进癌症研究和治疗的现状和未来的挑战,比较系统性的描述了肿瘤研究领域的组学类型,组学特征,常见的研究方式和常用的公共数据库等信息,内容比较多也很全面。
Abstract:
Historically, the primary focus of cancer research has been molecular and clinical studies of a few essential pathways and genes. Recent years have seen the rapid accumulation of large-scale cancer …
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Historically, the primary focus of cancer research has been molecular and clinical studies of a few essential pathways and genes. Recent years have seen the rapid accumulation of large-scale cancer omics data catalysed by breakthroughs in high-throughput technologies. This fast data growth has given rise to an evolving concept of 'big data' in cancer, whose analysis demands large computational resources and can potentially bring novel insights into essential questions. Indeed, the combination of big data, bioinformatics and artificial intelligence has led to notable advances in our basic understanding of cancer biology and to translational advancements. Further advances will require a concerted effort among data scientists, clinicians, biologists and policymakers. Here, we review the current state of the art and future challenges for harnessing big data to advance cancer research and treatment.
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847.
钟鸣
(2022-10-31 17:38):
#paper doi:10.1186/s12864-022-08678-3 BMC Genomics,2022,From a large-scale genomic analysis of insertion sequences to insights into their regulatory roles in prokaryotes
插入序列(IS)作为可转移的外源序列,经常插入在原核生物基因组中。IS的插入有何影响?本文通过大范围的比较基因组分析探究了这个问题。在8481个基因组中鉴定到612700个IS插入,除了对这些IS和基因组类别进行分类描述外,作者还重点分析了IS的插入位置的偏好以及对基因组功能上的影响,他们发现IS普遍插入在基因功能与转录调控和转运活性有关的基因两侧,从而影响宿主的表型。IS影响宿主表型已是屡见不鲜,本研究从更广阔的范围内印证了这点,加深了我们对IS的了解,期望以后看到本领域更多的了解和新发现。
Abstract:
BACKGROUND: Insertion sequences (ISs) are mobile repeat sequences and most of them can copy themselves to new host genome locations, leading to genome plasticity and gene regulation in prokaryotes. In …
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BACKGROUND: Insertion sequences (ISs) are mobile repeat sequences and most of them can copy themselves to new host genome locations, leading to genome plasticity and gene regulation in prokaryotes. In this study, we present functional and evolutionary relationships between IS and neighboring genes in a large-scale comparative genomic analysis.RESULTS: IS families were located in all prokaryotic phyla, with preferential occurrence of IS3, IS4, IS481, and IS5 families in Alpha-, Beta-, and Gammaproteobacteria, Actinobacteria and Firmicutes as well as in eukaryote host-associated organisms and autotrophic opportunistic pathogens. We defined the concept of the IS-Gene couple (IG), which allowed to highlight the functional and regulatory impacts of an IS on the closest gene. Genes involved in transcriptional regulation and transport activities were found overrepresented in IG. In particular, major facilitator superfamily (MFS) transporters, ATP-binding proteins and transposases raised as favorite neighboring gene functions of IS hotspots. Then, evolutionary conserved IS-Gene sets across taxonomic lineages enabled the classification of IS-gene couples into phylum, class-to-genus, and species syntenic IS-Gene couples. The IS5, IS21, IS4, IS607, IS91, ISL3 and IS200 families displayed two to four times more ISs in the phylum and/or class-to-genus syntenic IGs compared to other IS families. This indicates that those families were probably inserted earlier than others and then subjected to horizontal transfer, transposition and deletion events over time. In phylum syntenic IG category, Betaproteobacteria, Crenarchaeota, Calditrichae, Planctomycetes, Acidithiobacillia and Cyanobacteria phyla act as IS reservoirs for other phyla, and neighboring gene functions are mostly related to transcriptional regulators. Comparison of IS occurrences with predicted regulatory motifs led to ~ 26.5% of motif-containing ISs with 2 motifs per IS in average. These results, concomitantly with short IS-Gene distances, suggest that those ISs would interfere with the expression of neighboring genes and thus form strong candidates for an adaptive pairing.CONCLUSIONS: All together, our large-scale study provide new insights into the IS genetic context and strongly suggest their regulatory roles.
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848.
Vincent
(2022-10-31 15:22):
#paper Obtaining genetics insights from deep learning via explainable artificial intelligence, Nature Reviews Genetics https://doi.org/10.1038/ s41576-022-00532-2 基于深度学习的人工智能模型在基因组功能预测中发挥重要作用,被认为是当下表现最好的模型(state of the art)。但是由于深度学习模型的复杂性, 它们往往被认为是黑箱模型,其预测效果/机制往往很难被解释,但是基因组的研究中很多时候作用机制(过程)比预测效果(结果)更有价值。这篇review paper总结了近年来新兴的可解释性机器学习(xAI)技术在基因组领域的研究进展,展望了该技术在揭示生物机理方面的潜能。这篇文章主要以regulatory genomics 作为例子, 总结归纳了4种解释机器学习模型的技术:基于模型的解释(检查隐含层的神经元活动,注意力机制),影响的数学传播(前向传播/后向传播), 特征相互作用的鉴别,和基于先验知识的透明模型,以及这几种技术在高通量测序技术中的潜在假设和相应的局限性。
Abstract:
Artificial intelligence (AI) models based on deep learning now represent the state of the art for making functional predictions in genomics research. However, the underlying basis on which predictive models …
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Artificial intelligence (AI) models based on deep learning now represent the state of the art for making functional predictions in genomics research. However, the underlying basis on which predictive models make such predictions is often unknown. For genomics researchers, this missing explanatory information would frequently be of greater value than the predictions themselves, as it can enable new insights into genetic processes. We review progress in the emerging area of explainable AI (xAI), a field with the potential to empower life science researchers to gain mechanistic insights into complex deep learning models. We discuss and categorize approaches for model interpretation, including an intuitive understanding of how each approach works and their underlying assumptions and limitations in the context of typical high-throughput biological datasets.
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849.
song
(2022-10-31 12:02):
#paper Conditional Diffusion Probabilistic Model for Speech Enhancement, https://arxiv.org/abs/2202.05256# 一般的扩散模型在speech相关的task上表现并不优秀,原因是扩散模型假设所有的噪音是符合高斯分布的,而在speech任务中只有少量噪音的高斯噪音(白噪音)更多的是各种stationary和non-stationary noise。本文解决这一问题的方法是在reverse和diffuse过程中除了基于上一步的输出外,还基于一个带噪声语音,y,从每一步乘以一个高斯噪音变成乘以带噪声语音于当前步语音的差于高斯噪音的积。在这个过程中模型学到了带噪声语音(非高斯噪音)的特征。这个方法解决了非高斯分布数据使用扩散模型的问题。但语音增强问题有其特殊性,语音增强任务的数据集本身就带有干净语音和噪声语音,使这个任务较为适合这个方法,其他语音任务不一定会有干净语音作为输入。比如语音转换任务就没有大量目标语音作为干净语音输入,可以在此基础上再做研究
arXiv,
2022.
Abstract:
Speech enhancement is a critical component of many user-oriented audio applications, yet current systems still suffer from distorted and unnatural outputs. While generative models have shown strong potential in speech …
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Speech enhancement is a critical component of many user-oriented audio applications, yet current systems still suffer from distorted and unnatural outputs. While generative models have shown strong potential in speech synthesis, they are still lagging behind in speech enhancement. This work leverages recent advances in diffusion probabilistic models, and proposes a novel speech enhancement algorithm that incorporates characteristics of the observed noisy speech signal into the diffusion and reverse processes. More specifically, we propose a generalized formulation of the diffusion probabilistic model named conditional diffusion probabilistic model that, in its reverse process, can adapt to non-Gaussian real noises in the estimated speech signal. In our experiments, we demonstrate strong performance of the proposed approach compared to representative generative models, and investigate the generalization capability of our models to other datasets with noise characteristics unseen during training.
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850.
惊鸿
(2022-10-31 10:45):
#paper Clipping cancer with CRISPR Cancer Cytopathology ( IF 4.264 ) Pub Date : 2018-01-01 , DOI: 10.1002/cncy.21964 它是一种细菌自我保护,不然细菌就会在几分钟内死亡。许多细菌(和古生菌)可以扭转其病毒攻击的机制的侦查已迅速成为生物医学中最热门的研究领域之一。细菌 CRISPR(成簇的规则间隔短回文重复序列)-Cas9(CRISPR 相关蛋白 9)酶系统被重新用作精确的 DNA 编辑工具,已在广泛的应用中显示出早期前景,包括努力发现癌症通路和设计更有针对性的化疗药物。然而,科学家们敦促谨慎对待意外基因或产生脱靶效应的风险,以及永久改变遗传 DNA 的可能性;这让人想起 1990 年代后期围绕基因治疗的安全和伦理问题。在 CRISPR 系统的希望和严格审查中,最近的几项研究表明,新工具如何避免过去的一些陷阱,以及它如何在准备用于临床之前克服更多陷阱。该技术需要面临许多挑战,并且要避免对该项技术的过多幻想,否则将会给我们带来失望。
851.
李翛然
(2022-10-31 09:48):
#paper TET1 is a beige adipocyte-selective epigenetic suppressor of thermogenesis doi: https://doi.org/10.1038/s41467-020-18054-y
关于TET1 ,文献报道Tumor suppressor应该是没有问题,做为重组蛋白治疗肿瘤,我接下来要调研一下临床上哪类肿瘤病人是否有TET1缺失的现象,由此来判断肿瘤是否在TET1不缺失的情况下不好生长,确定其临床价值,还有一个要考虑的是这2篇文章介绍的TET1压抑脂肪细胞热能量代谢,维他命C作用在TET1压制somatic cell reprogramming,这2个现象是否可能导致严重的副作用,限制TET1的剂量
Abstract:
It has been suggested that beige fat thermogenesis is tightly controlled by epigenetic regulators that sense environmental cues such as temperature. Here, we report that subcutaneous adipose expression of the …
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It has been suggested that beige fat thermogenesis is tightly controlled by epigenetic regulators that sense environmental cues such as temperature. Here, we report that subcutaneous adipose expression of the DNA demethylase TET1 is suppressed by cold and other stimulators of beige adipocyte thermogenesis. TET1 acts as an autonomous repressor of key thermogenic genes, including Ucp1 and Ppargc1a, in beige adipocytes. Adipose-selective Tet1 knockout mice generated by using Fabp4-Cre improves cold tolerance and increases energy expenditure and protects against diet-induced obesity and insulin resistance. Moreover, the suppressive role of TET1 in the thermogenic gene regulation of beige adipocytes is largely DNA demethylase-independent. Rather, TET1 coordinates with HDAC1 to mediate the epigenetic changes to suppress thermogenic gene transcription. Taken together, TET1 is a potent beige-selective epigenetic breaker of the thermogenic gene program. Our findings may lead to a therapeutic strategy to increase energy expenditure in obesity and related metabolic disorders.
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852.
前进
(2022-10-30 21:26):
#paper Shi J, He Y, Kong Y, et al. XMorpher: Full Transformer for Deformable Medical Image Registration via Cross Attention[C]//International Conference on Medical Image Computing and Computer-Assisted Intervention. Springer, Cham, 2022: 217-226.现有的深度网络专注于单个图像的特征提取,并且在对成对图像执行的配准任务方面受到限制。因此,本文提出了一种新的骨干网络XMorpher,有效地对变形配准中成对特征进行表示。1) 它提出了一种新的Transformer架构,包括双并行特征提取网络,该网络通过Cross Attention来改变信息,从而发现多级语义对应关系,同时逐步提取各自的特征,以实现最终的有效配准。2) 它提出了Cross Attention Transformer(CAT)块,以建立图像之间的注意力机制,该机制能够自动找到对应关系,并促使特征在网络中有效融合。3) 它限制了不同大小的基本窗口和搜索窗口之间的计算,从而集中于可变形配准的局部变换,同时提高了计算效率。XMorpher使Voxelmorph在DSC上提高了2.8%,证明了其在变形配准中对配对图像的特征的有效表示。
Abstract:
An effective backbone network is important to deep learning-based Deformable Medical Image Registration (DMIR), because it extracts and matches the features between two images to discover the mutual correspondence for …
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An effective backbone network is important to deep learning-based Deformable Medical Image Registration (DMIR), because it extracts and matches the features between two images to discover the mutual correspondence for fine registration. However, the existing deep networks focus on single image situation and are limited in registration task which is performed on paired images. Therefore, we advance a novel backbone network, XMorpher, for the effective corresponding feature representation in DMIR. 1) It proposes a novel full transformer architecture including dual parallel feature extraction networks which exchange information through cross attention, thus discovering multi-level semantic correspondence while extracting respective features gradually for final effective registration. 2) It advances the Cross Attention Transformer (CAT) blocks to establish the attention mechanism between images which is able to find the correspondence automatically and prompts the features to fuse efficiently in the network. 3) It constrains the attention computation between base windows and searching windows with different sizes, and thus focuses on the local transformation of deformable registration and enhances the computing efficiency at the same time. Without any bells and whistles, our XMorpher gives Voxelmorph 2.8% improvement on DSC, demonstrating its effective representation of the features from the paired images in DMIR. We believe that our XMorpher has great application potential in more paired medical images. Our XMorpher is open on https://github.com/Solemoon/XMorpher
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853.
洪媛媛
(2022-10-30 12:16):
#paper https://doi.org/10.1038/s41467-022-32995-6 nature communications 2022. Cost-effective methylome sequencing of cell-free DNA for accurately detecting and locating cancer. 这篇文章介绍了一种富集cfDNA CpG区域的NGS建库方法(cfMethyl-Seq),cfMethyl-Seq比全基因组甲基化测序更节省数据量,而且比传统的RRBS方法更适合用于cfDNA CpG区域的富集。该研究首先通过RRBS测序的癌症、癌旁组织样本,以及cfMethyl-Seq测序的健康人血浆样本,筛选出癌症早筛和组织溯源(TOO)marker,然后将cfMethyl-Seq测序的217癌症和131健康人血浆样本,分成训练集和测试集,在训练集建模,在测试集验证性能。
Abstract:
Early cancer detection by cell-free DNA faces multiple challenges: low fraction of tumor cell-free DNA, molecular heterogeneity of cancer, and sample sizes that are not sufficient to reflect diverse patient …
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Early cancer detection by cell-free DNA faces multiple challenges: low fraction of tumor cell-free DNA, molecular heterogeneity of cancer, and sample sizes that are not sufficient to reflect diverse patient populations. Here, we develop a cancer detection approach to address these challenges. It consists of an assay, cfMethyl-Seq, for cost-effective sequencing of the cell-free DNA methylome (with > 12-fold enrichment over whole genome bisulfite sequencing in CpG islands), and a computational method to extract methylation information and diagnose patients. Applying our approach to 408 colon, liver, lung, and stomach cancer patients and controls, at 97.9% specificity we achieve 80.7% and 74.5% sensitivity in detecting all-stage and early-stage cancer, and 89.1% and 85.0% accuracy for locating tissue-of-origin of all-stage and early-stage cancer, respectively. Our approach cost-effectively retains methylome profiles of cancer abnormalities, allowing us to learn new features and expand to other cancer types as training cohorts grow.
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854.
负负
(2022-10-29 19:25):
#paper Understanding the role of individual units in a deep neural network (https://doi.org/10.1073/pnas.1907375117) PNAS, 2020.
作者通过对Place365数据集上训练得到的VGG16网络的神经元激活图进行上采样观察到了深度学习神经网络中的单个神经元所学习到的概念特征,讨论了这些神经元在“场景分类器”以及生成对抗网络中的“生成器”中的作用,最后讨论了这一发现的应用前景。本项工作的主要研究发现:
1、场景分类器中较“浅”层的神经元倾向于学习到“颜色”、“材质”等抽象概念,较“深”层的神经元倾向于学习到“物体”、“零件”等具体概念。
2、部分神经元对场景识别有重要的作用,关闭这些神经元会导致场景识别能力降低,在多个场景识别任务中都发挥重要作用的神经元具有更好的可解释性。
3、GANs中生成器的神经元学习到的特征与辨别器相反,即,“浅”层的神经元倾向于学习具体概念,而较“深”层的神经元倾向于学习到抽象概念。
4、关闭或启动生成器中的部分神经元,会使生成的图片中去除或增添部分场景元素,同时生成器会根据场景的特性在合适的位置生成物体,因此可以通过操纵GANs中的神经元的激活情况来进行场景绘画。
IF:9.400Q1
Proceedings of the National Academy of Sciences of the United States of America,
2020-12-01.
DOI: 10.1073/pnas.1907375117
PMID: 32873639
Abstract:
Deep neural networks excel at finding hierarchical representations that solve complex tasks over large datasets. How can we humans understand these learned representations? In this work, we present network dissection, …
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Deep neural networks excel at finding hierarchical representations that solve complex tasks over large datasets. How can we humans understand these learned representations? In this work, we present network dissection, an analytic framework to systematically identify the semantics of individual hidden units within image classification and image generation networks. First, we analyze a convolutional neural network (CNN) trained on scene classification and discover units that match a diverse set of object concepts. We find evidence that the network has learned many object classes that play crucial roles in classifying scene classes. Second, we use a similar analytic method to analyze a generative adversarial network (GAN) model trained to generate scenes. By analyzing changes made when small sets of units are activated or deactivated, we find that objects can be added and removed from the output scenes while adapting to the context. Finally, we apply our analytic framework to understanding adversarial attacks and to semantic image editing.
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855.
林海onrush
(2022-10-29 13:58):
#paper,Model Evaluation, Model Selection, and Algorithm
Selection in Machine Learning , url : https://arxiv.org/abs/1811.12808#,
本论文回顾了用于解决模型评估、模型选择和算法选择三项任务的不同技术,并参考理论和实证研究讨
论了每一项技术的主要优势和劣势。进而,给出建议以促进机器学习研究与应用方面的最佳实践。
详细论文解析见下面pdf
arXiv,
2018.
DOI: 10.48550/arXiv.1811.12808
Abstract:
The correct use of model evaluation, model selection, and algorithm selection techniques is vital in academic machine learning research as well as in many industrial settings. This article reviews different …
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The correct use of model evaluation, model selection, and algorithm selection techniques is vital in academic machine learning research as well as in many industrial settings. This article reviews different techniques that can be used for each of these three subtasks and discusses the main advantages and disadvantages of each technique with references to theoretical and empirical studies. Further, recommendations are given to encourage best yet feasible practices in research and applications of machine learning. Common methods such as the holdout method for model evaluation and selection are covered, which are not recommended when working with small datasets. Different flavors of the bootstrap technique are introduced for estimating the uncertainty of performance estimates, as an alternative to confidence intervals via normal approximation if bootstrapping is computationally feasible. Common cross-validation techniques such as leave-one-out cross-validation and k-fold cross-validation are reviewed, the bias-variance trade-off for choosing k is discussed, and practical tips for the optimal choice of k are given based on empirical evidence. Different statistical tests for algorithm comparisons are presented, and strategies for dealing with multiple comparisons such as omnibus tests and multiple-comparison corrections are discussed. Finally, alternative methods for algorithm selection, such as the combined F-test 5x2 cross-validation and nested cross-validation, are recommended for comparing machine learning algorithms when datasets are small.
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856.
林海onrush
(2022-10-29 13:51):
#paper,Formal Algorithms for Transformers,url:https://arxiv.org/pdf/2207.09238.pdf,在过去5年多的时间里,Transfermers在多个领域表现出惊人的效果。但是,对于Transformers算法的描述基本都集中在使用图形、文字描述、或针对优化部分的解释,并没有一篇论文给出一个较为完整的Algorithm伪代码。deepmind官方给出了形式化算法伪代码,论文详解见下面PDF
arXiv,
2022.
DOI: 10.48550/arXiv.2207.09238
Abstract:
This document aims to be a self-contained, mathematically precise overview of transformer architectures and algorithms (*not* results). It covers what transformers are, how they are trained, what they are used …
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This document aims to be a self-contained, mathematically precise overview of transformer architectures and algorithms (*not* results). It covers what transformers are, how they are trained, what they are used for, their key architectural components, and a preview of the most prominent models. The reader is assumed to be familiar with basic ML terminology and simpler neural network architectures such as MLPs.
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857.
林海onrush
(2022-10-29 13:25):
#paper,CAUSAL DISCOVERY WITH REINFORCEMENT
LEARNING,论文地址:https://arxiv.org/pdf/1906.04477.pdf,官方视频介绍:https://iclr.cc/virtual_2020/poster_S1g2skStPB.html,
因果研究作为下一个潜在的热点,已经吸引了机器学习/深度学习领域的的广泛关注,因果研究中一个经典的问题是「因果发现」问题——从被动可观测的数据中发现潜在的因果图结构。
此论文是华为诺亚方舟实验室被 ICLR 2020 接收的一篇满分论文。在此论文中,华为诺亚方舟实验室因果研究团队将强化学习应用到打分法的因果发现算法中,通过基于自注意力机制的 encoder-decoder 神经网络模型探索数据之间的关系,结合因果结构的条件,并使用策略梯度的强化学习算法对神经网络参数进行训练,最终得到因果图结构。在学术界常用的一些数据模型中,该方法在中等规模的图上的表现优于其他方法,包括传统的因果发现算法和近期的基于梯度的算法。同时该方法非常灵活,可以和任意的打分函数结合使用。
arXiv,
2019.
DOI: 10.48550/arXiv.1906.04477
Abstract:
Discovering causal structure among a set of variables is a fundamental problem in many empirical sciences. Traditional score-based casual discovery methods rely on various local heuristics to search for a …
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Discovering causal structure among a set of variables is a fundamental problem in many empirical sciences. Traditional score-based casual discovery methods rely on various local heuristics to search for a Directed Acyclic Graph (DAG) according to a predefined score function. While these methods, e.g., greedy equivalence search, may have attractive results with infinite samples and certain model assumptions, they are usually less satisfactory in practice due to finite data and possible violation of assumptions. Motivated by recent advances in neural combinatorial optimization, we propose to use Reinforcement Learning (RL) to search for the DAG with the best scoring. Our encoder-decoder model takes observable data as input and generates graph adjacency matrices that are used to compute rewards. The reward incorporates both the predefined score function and two penalty terms for enforcing acyclicity. In contrast with typical RL applications where the goal is to learn a policy, we use RL as a search strategy and our final output would be the graph, among all graphs generated during training, that achieves the best reward. We conduct experiments on both synthetic and real datasets, and show that the proposed approach not only has an improved search ability but also allows a flexible score function under the acyclicity constraint.
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858.
尹志
(2022-10-27 20:44):
#paper doi: https://doi.org/10.48550/arXiv.1708.02002,Focal Loss for Dense Object Detection. (ICCV 2017) 这是一篇目标检测领域的经典的论文,我们知道,一直以来,目标检测领域有两类模型,单阶段和二阶段检测模型。前者以yolo和ssd为主,后者基本上是R-CNN派生出来的。一般而言,单阶段的目标检测算法速度快于二阶段检测算法,而准确性上弱于二阶段算法。原理上,二阶段检测算法基本是第一步生成一堆的候选目标框,然后第二步精准分类这些候选目标框;而单阶段检测算法是直接生成一堆(大量)的检测框。那么是不是提出一个单阶段的检测算法,速度也快,准确性也可以媲美二阶段算法呢?文章认为,单阶段在准确性上目前比不过二阶段算法的原因,是因为存在类别不平衡的问题。在二阶段算法中,我们通过第一阶段已经过滤了大多数的背景样本了,但单阶段算法一次生成的候选框非常密集,其中前景-背景类别的不平衡就非常严重,这也导致准确率上不去。因此作者提出,我们在常规的交叉熵里引入一个缩放因子,这个缩放因子在训练中能够自动对容易的样本进行降权重,从而让模型能更好的处理难例。这就是大名鼎鼎的focal loss。基于focal loss,作者设计了一个单阶段目标检测网络:RetinaNet, 通过实验对比,RetinaNet不论在速度上还是准确性上,都获得了SOTA的性能,在COCO数据集上获得了39.1的AP(这在当年是非常优秀的成绩)
arXiv,
2018.
DOI: 10.48550/arXiv.1708.02002
Abstract:
The highest accuracy object detectors to date are based on a two-stage approach popularized by R-CNN, where a classifier is applied to a sparse set of candidate object locations. In …
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The highest accuracy object detectors to date are based on a two-stage approach popularized by R-CNN, where a classifier is applied to a sparse set of candidate object locations. In contrast, one-stage detectors that are applied over a regular, dense sampling of possible object locations have the potential to be faster and simpler, but have trailed the accuracy of two-stage detectors thus far. In this paper, we investigate why this is the case. We discover that the extreme foreground-background class imbalance encountered during training of dense detectors is the central cause. We propose to address this class imbalance by reshaping the standard cross entropy loss such that it down-weights the loss assigned to well-classified examples. Our novel Focal Loss focuses training on a sparse set of hard examples and prevents the vast number of easy negatives from overwhelming the detector during training. To evaluate the effectiveness of our loss, we design and train a simple dense detector we call RetinaNet. Our results show that when trained with the focal loss, RetinaNet is able to match the speed of previous one-stage detectors while surpassing the accuracy of all existing state-of-the-art two-stage detectors. Code is at: this https URL.
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859.
白鸟
(2022-10-27 09:36):
#paper doi:#paper doi:https://doi.org/10.1038/s41587-022-01468-y Haplotype-aware analysis of somatic copy number variations from single-cell transcriptomes.
单细胞转录组体细胞拷贝数变异的单倍型感知分析
基因组不稳定性和转录程序的异常改变都在癌症中发挥重要作用。单细胞 RNA 测序 (scRNA-seq) 在一次检测中能够同时研究肿瘤异质性的遗传和非遗传来源。虽然有许多工具可以从外显子组和全基因组测序数据中识别CNV,针对单细胞RNA-seq数据中检测CNV的方法非常稀缺。常用的inferCNV和copyKAT都只是利用转录组的基因表达信息进行CNV推断。最近,哈佛医学院的研究者提出了一种计算方法,Numbat,它将基于群体的定相(population-based phasing)获得的单倍型信息与等位基因和表达信号相结合,能准确推断单个细胞中的等位基因特异性CNV并重建它们的谱系关系。也就是说它通过基因表达和等位基因两个证据链,进行联合推断,避免CNV推断误判。Numbat利用亚克隆之间的进化关系来迭代推断单细胞拷贝数分布和肿瘤克隆系统发育。比其他工具进行基准测试,对包括多发性骨髓瘤、胃癌、乳腺癌和甲状腺癌在内的 22 个肿瘤样本的分析表明,Numbat可以重建肿瘤拷贝数分布,并准确识别肿瘤微环境中的恶性细胞。Numbat 不需要样本匹配的 DNA 数据,也不需要先验基因分型,适用于广泛的实验环境和癌症类型。总之,Numbat 可以扩展单细胞RNA-seq数据来探测细胞的CNV景观以及转录组景观。需要思考的是我们可能需要更多不同遗传背景的人群定相单倍型信息来辅助推断。另外,肿瘤基线倍性估计仍是拷贝数分析中的有挑战性的问题。
Abstract:
Genome instability and aberrant alterations of transcriptional programs both play important roles in cancer. Single-cell RNA sequencing (scRNA-seq) has the potential to investigate both genetic and nongenetic sources of tumor …
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Genome instability and aberrant alterations of transcriptional programs both play important roles in cancer. Single-cell RNA sequencing (scRNA-seq) has the potential to investigate both genetic and nongenetic sources of tumor heterogeneity in a single assay. Here we present a computational method, Numbat, that integrates haplotype information obtained from population-based phasing with allele and expression signals to enhance detection of copy number variations from scRNA-seq. Numbat exploits the evolutionary relationships between subclones to iteratively infer single-cell copy number profiles and tumor clonal phylogeny. Analysis of 22 tumor samples, including multiple myeloma, gastric, breast and thyroid cancers, shows that Numbat can reconstruct the tumor copy number profile and precisely identify malignant cells in the tumor microenvironment. We identify genetic subpopulations with transcriptional signatures relevant to tumor progression and therapy resistance. Numbat requires neither sample-matched DNA data nor a priori genotyping, and is applicable to a wide range of experimental settings and cancer types.
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860.
哪有情可长
(2022-10-26 20:33):
#paper doi:#paper doi:doi:10.1038/ng.592, OsSPL14 promotes panicle branching and higher grainproductivity in rice.作物产量三要素主要是亩穗数、穗粒数和千粒重。提高产量主要是提高三要素之间的协同作用。水稻的第二次“绿色革命”是通过降低株高来增加了水稻的产量。而现在有人认为在水稻中IPA这个基因是新型的"绿色革命"基因。该基因能够能够在水稻的生殖期通过在水稻幼穗内高表达促进水稻穗分枝和籽粒产量。小麦中关于SBP蛋白的研究有很多,通过同源blast,在小麦中也鉴定到了IPA的同源基因。文章在2017年发表在《Plant Physiology》“Functional conservation and divergence among homoeologs of TaSPL20 and TaSPL21, two SBP-box genes governing yield-related traits in hexaploid wheat”,作者发现普通小麦部分同源基因TaSPL20和TaSPL21在小麦长期的驯化和遗传改良过程中产生功能分化,其优异的自然变异在我国小麦育种进程中受到了定向选择并被广泛应用,但是这个文中中验证基因由于当初小麦转基因比较难,文中中验证是在水稻中进行的,证明该基因增加了籽粒大小,从而增加了产量。如果是在小麦中验证会更好。
Abstract:
Identification of alleles that improve crop production and lead to higher-yielding varieties are needed for food security. Here we show that the quantitative trait locus WFP (WEALTHY FARMER'S PANICLE) encodes …
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Identification of alleles that improve crop production and lead to higher-yielding varieties are needed for food security. Here we show that the quantitative trait locus WFP (WEALTHY FARMER'S PANICLE) encodes OsSPL14 (SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 14, also known as IPA1). Higher expression of OsSPL14 in the reproductive stage promotes panicle branching and higher grain yield in rice. OsSPL14 controls shoot branching in the vegetative stage and is affected by microRNA excision. We also demonstrate the feasibility of using the OsSLP14(WFP) allele to increase rice crop yield. Introduction of the high-yielding OsSPL14(WFP) allele into the standard rice variety Nipponbare resulted in increased rice production.
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