当前共找到 1276 篇文献分享,本页显示第 561 - 580 篇。
561.
张贝
(2023-06-30 23:14):
#paper DNA methylation-based classification of central nervous system tumours Nature. 2018 Mar 22;555(7697):469-474.doi:10.1038/nature26000
肿瘤的正确诊断对于后期治疗至关重要,然而在已知的近100多种中枢神经系统肿瘤 (central nervous system tumor,CNS tumor)中,相关标准化的诊断面临很大的挑战。为了高效、迅速的对CNS肿瘤进行分类,作者开发了一个机器学习模型,它可以对甲基化数据进行分类。开发出来的程序经过训练后,可以使用甲基化特征鉴定91种CNS肿瘤。训练集采用的参照数据来自约2800名癌症患者。作者在1104例已经经过人工检查的中枢神经系统肿瘤上进行了测试,发现有12%例存在误诊。该模型不仅可以提高诊断准确率,而且还可以鉴定出新型罕见肿瘤。为了让这种新方法得到广泛应用,作者生成了一款免费在线工具 (Molecular Neuropathology 2.0; http://www.kitz-heidelberg.de/molecular-diagnostics),可以在几分钟内分析上传的数据。自2016年12月上线以来,该工具已被使用逾4500次,用户可以选择分享他们的数据,以便进一步优化算法。作者总结表示,将甲基化特征与脑肿瘤自动分类器整合起来还可以为创造类似的肿瘤分类算法用于诊断其它癌症类型提供一个蓝图。
Abstract:
Accurate pathological diagnosis is crucial for optimal management of patients with cancer. For the approximately 100 known tumour types of the central nervous system, standardization of the diagnostic process has …
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Accurate pathological diagnosis is crucial for optimal management of patients with cancer. For the approximately 100 known tumour types of the central nervous system, standardization of the diagnostic process has been shown to be particularly challenging-with substantial inter-observer variability in the histopathological diagnosis of many tumour types. Here we present a comprehensive approach for the DNA methylation-based classification of central nervous system tumours across all entities and age groups, and demonstrate its application in a routine diagnostic setting. We show that the availability of this method may have a substantial impact on diagnostic precision compared to standard methods, resulting in a change of diagnosis in up to 12% of prospective cases. For broader accessibility, we have designed a free online classifier tool, the use of which does not require any additional onsite data processing. Our results provide a blueprint for the generation of machine-learning-based tumour classifiers across other cancer entities, with the potential to fundamentally transform tumour pathology.
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562.
钟鸣
(2023-06-30 22:31):
#paper doi:10.1093/molbev/msad102 Caecilian Genomes Reveal the Molecular Basis of Adaptation and Convergent Evolution of Limblessness in Snakes and Caecilians
这是一篇比较基因组阐释进化问题的论文,比较的是蚓螈与蛇的基因组的共同特征,因为二者趋同进化至无足。作者分析了4个内容:重复区域分析、基因家族分析、正选择基因分析、ZRS增强子损失分析。分析结果集中于2点,第一点是这两个物种的基因组的 69% 以上都是由重复区域组成,其中逆转录转座子最为丰富。第二个发现是蚓螈的ZRS基因的增强子区域发生了缺失,这个基因在蛇中发生了突变,且该突变基因导入小鼠后会产生蛇样突变。这组证据强烈暗示该基因与无足表型的关联。
Abstract:
We present genome sequences for the caecilians Geotrypetes seraphini (3.8 Gb) and Microcaecilia unicolor (4.7 Gb), representatives of a limbless, mostly soil-dwelling amphibian clade with reduced eyes, and unique putatively …
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We present genome sequences for the caecilians Geotrypetes seraphini (3.8 Gb) and Microcaecilia unicolor (4.7 Gb), representatives of a limbless, mostly soil-dwelling amphibian clade with reduced eyes, and unique putatively chemosensory tentacles. More than 69% of both genomes are composed of repeats, with retrotransposons being the most abundant. We identify 1,150 orthogroups that are unique to caecilians and enriched for functions in olfaction and detection of chemical signals. There are 379 orthogroups with signatures of positive selection on caecilian lineages with roles in organ development and morphogenesis, sensory perception, and immunity amongst others. We discover that caecilian genomes are missing the zone of polarizing activity regulatorysequence (ZRS) enhancer of Sonic Hedgehog which is also mutated in snakes. In vivo deletions have shown ZRS is required for limb development in mice, thus, revealing a shared molecular target implicated in the independent evolution of limblessness in snakes and caecilians.
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563.
白鸟
(2023-06-30 22:26):
#paper https://www.frontiersin.org/articles/10.3389/fimmu.2023.1147718/full. The immunomodulatory mechanisms for acupuncture practice.
缘起:昨天跟同事聊起,他得了一种比较奇怪的病-面肌炎,跟自身免疫疾病有关,医生给他开了抗病毒的药物,特别提到对不同的穴位用针灸进行治疗。我一直也觉得中医和免疫系统应该是想通的,需要科学的解释。所以,想找一篇针灸和免疫相关的文献看看。
文献中,提到针灸是一种安全有效的调节人体免疫系统的医疗实践。需要针灸基于与现代西医不同的系统,因此当前的研究重点是针灸的作用和相关的神经生物学机制。本文对针灸的免疫调节机制进行综述,系统整合现有研究成果,阐明针灸对先天性和适应性免疫反应的调节作用,以及针灸免疫调节神经解剖学机制,包括完整的自主反射途径。这对于针灸医学的普及具有重要意义。
比较惭愧的是,文章我还没细读。最近在读免疫书,希望能加深一些人体免疫系统如何具体运行的理解。
Abstract:
The system physiology approaches that emerge in western countries in recent years echo the holistic view of ancient Traditional Chinese Medicine (TCM) practices that deal with the root, rather than …
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The system physiology approaches that emerge in western countries in recent years echo the holistic view of ancient Traditional Chinese Medicine (TCM) practices that deal with the root, rather than only the symptoms of diseases. Particularly, TCM practices, including acupuncture, emphasize the mobilization of self-healing mechanisms to bring back body homeostasis. Acupuncture has been practiced for over two thousand years to modulate body physiology stimulation at specific body regions (acupoints). With the development of various research on acupuncture therapy, its regulatory effect on the immune system has been gradually recognized, especially on immunological diseases, including infectious and allergic diseases. In this study, we reviewed the immunomodulatory mechanism of acupuncture and systematically integrates existing research to respectively elucidate the modulatory mechanisms of acupuncture on the innate immune system, adaptive immune system, and well-known neuroanatomical mechanisms, including intact somatosensory-autonomic reflex pathway. With the advances made in recent systems physiology studies, we now have a great opportunity to gain insight into how acupuncture modulates immunity, and subsequently improves its efficacy.
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564.
半面阳光
(2023-06-30 22:13):
#paper DOI:https://doi.org/10.1093/bib/bbab380, Briefings in Bioinformatics, 2022, NiPTUNE: an automated pipeline for noninvasive prenatal testing in an accurate, integrative and flexible framework.这篇文章整合了一个完整的NIPT生物信息流程。文章测试了NIPT生信分析中QC、Fetal fraction估计、fetal gender判断等几个关键步骤的不同分析工具和方法,给出了一套分析效果较好的工具组合。
Abstract:
Noninvasive prenatal testing (NIPT) consists of determining fetal aneuploidies by quantifying copy number alteration from the sequencing of cell-free DNA (cfDNA) from maternal blood. Due to the presence of cfDNA …
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Noninvasive prenatal testing (NIPT) consists of determining fetal aneuploidies by quantifying copy number alteration from the sequencing of cell-free DNA (cfDNA) from maternal blood. Due to the presence of cfDNA of fetal origin in maternal blood, in silico approaches have been developed to accurately predict fetal aneuploidies. Although NIPT is becoming a new standard in prenatal screening of chromosomal abnormalities, there are no integrated pipelines available to allow rapid, accurate and standardized data analysis in any clinical setting. Several tools have been developed, however often optimized only for research purposes or requiring enormous amount of retrospective data, making hard their implementation in a clinical context. Furthermore, no guidelines have been provided on how to accomplish each step of the data analysis to achieve reliable results. Finally, there is no integrated pipeline to perform all steps of NIPT analysis. To address these needs, we tested several tools for performing NIPT data analysis. We provide extensive benchmark of tools performances but also guidelines for running them. We selected the best performing tools that we benchmarked and gathered them in a computational pipeline. NiPTUNE is an open source python package that includes methods for fetal fraction estimation, a novel method for accurate gender prediction, a principal component analysis based strategy for quality control and fetal aneuploidies prediction. NiPTUNE is constituted by seven modules allowing the user to run the entire pipeline or each module independently. Using two cohorts composed by 1439 samples with 31 confirmed aneuploidies, we demonstrated that NiPTUNE is a valuable resource for NIPT analysis.
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565.
muton
(2023-06-30 21:57):
# Paper: Doeller, C. F., Barry, C., & Burgess, N. (2010). Evidence for grid cells in a human memory network. Nature, 463(7281), 657–661. https://doi.org/10.1038/nature08704
自由运动大鼠内嗅皮层中的网格细胞提供了自我定位的显著周期性表征,这表明了非常特殊的计算机制。然而,网格细胞在人类中的存在及其在整个大脑中的分布是未知的。本研究表明,大鼠内嗅皮层定向调节的网格细胞的优先放电方向与网格对齐,并且快跑与慢跑相比,网格细胞放电的空间组织更为明显。由于网格细胞的一致性特征,作者预测了在更宏观的信号,也就是人类的功能性磁共振成像(fMRI)记录中也会发现网格细胞的相关证据。因此,作者模拟老鼠的觅食任务,让参与者探索虚拟现实环境,结果显示fMRI激活和适应在跑步方向上显示出由速度调节的六倍旋转对称的特性。这种信号在鼻内/丘下、顶叶后部和内侧、颞外侧和前额叶内侧的网络中都有发现。并且该效应在右内嗅皮层表现最为明显,方向信号在内嗅皮层间的相干性与空间记忆表现相关。本研究提示了将单细胞电生理学与功能磁共振成像在系统神经科学中结合的潜在可能。本研究结果为人类的网格细胞样表征提供了证据,并暗示在支持空间认知和自传体记忆的区域网络中存在一种特定类型神经表征。
Abstract:
Grid cells in the entorhinal cortex of freely moving rats provide a strikingly periodic representation of self-location which is indicative of very specific computational mechanisms. However, the existence of grid …
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Grid cells in the entorhinal cortex of freely moving rats provide a strikingly periodic representation of self-location which is indicative of very specific computational mechanisms. However, the existence of grid cells in humans and their distribution throughout the brain are unknown. Here we show that the preferred firing directions of directionally modulated grid cells in rat entorhinal cortex are aligned with the grids, and that the spatial organization of grid-cell firing is more strongly apparent at faster than slower running speeds. Because the grids are also aligned with each other, we predicted a macroscopic signal visible to functional magnetic resonance imaging (fMRI) in humans. We then looked for this signal as participants explored a virtual reality environment, mimicking the rats' foraging task: fMRI activation and adaptation showing a speed-modulated six-fold rotational symmetry in running direction. The signal was found in a network of entorhinal/subicular, posterior and medial parietal, lateral temporal and medial prefrontal areas. The effect was strongest in right entorhinal cortex, and the coherence of the directional signal across entorhinal cortex correlated with spatial memory performance. Our study illustrates the potential power of combining single-unit electrophysiology with fMRI in systems neuroscience. Our results provide evidence for grid-cell-like representations in humans, and implicate a specific type of neural representation in a network of regions which supports spatial cognition and also autobiographical memory.
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566.
大勇
(2023-06-30 21:35):
#paper Dmitrieva-Posocco, O., Wong, A.C., Lundgren, P. et al. β-Hydroxybutyrate suppresses colorectal cancer. Nature 605, 160–165 (2022). https://doi.org/10.1038/s41586-022-04649-6 主要是讲述生酮饮食对小鼠结肠癌的抑制作用及可能的机制探讨,整篇文献降解较为精简,细节可以在文章中继续探索,生酮饮食对脂质、糖类和蛋白的代谢都会造成影响,从而导致结肠癌生长的抑制,酮类中的β羟丁酸可以通过Hcar2基因诱导Hopx的表达升高,从而抑制结肠癌进展。在生酮饮食研究中,其实还有其他研究表明生酮饮食会造成肿瘤的进展而非抑制,并且生酮饮食可能还会加速衰老和增加心血管疾病的风险,因此若非药用,日常不适宜进行尝试,目前在临床中没有太多的验证,而对于遗传代谢病中糖代谢异常的患者,生酮饮食则可能是他们目前最为稳妥的饮食方式,因为糖类可能对他们来说反而是毒药。
Abstract:
Colorectal cancer (CRC) is among the most frequent forms of cancer, and new strategies for its prevention and therapy are urgently needed. Here we identify a metabolite signalling pathway that …
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Colorectal cancer (CRC) is among the most frequent forms of cancer, and new strategies for its prevention and therapy are urgently needed. Here we identify a metabolite signalling pathway that provides actionable insights towards this goal. We perform a dietary screen in autochthonous animal models of CRC and find that ketogenic diets exhibit a strong tumour-inhibitory effect. These properties of ketogenic diets are recapitulated by the ketone body β-hydroxybutyrate (BHB), which reduces the proliferation of colonic crypt cells and potently suppresses intestinal tumour growth. We find that BHB acts through the surface receptor Hcar2 and induces the transcriptional regulator Hopx, thereby altering gene expression and inhibiting cell proliferation. Cancer organoid assays and single-cell RNA sequencing of biopsies from patients with CRC provide evidence that elevated BHB levels and active HOPX are associated with reduced intestinal epithelial proliferation in humans. This study thus identifies a BHB-triggered pathway regulating intestinal tumorigenesis and indicates that oral or systemic interventions with a single metabolite may complement current prevention and treatment strategies for CRC.
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567.
笑对人生
(2023-06-30 21:33):
#paper doi: 10.1038/s41586-021-03894-5. Epub 2021 Sep 8. Bentham R, et al. Using DNA sequencing data to quantify T cell fraction and therapy response. Nature. 2021 Sep;597(7877):555-560. doi: 10.1038/s41586-021-03894-5. Epub 2021 Sep 8.
在V(D)J重排过程中,T细胞受体alpha链编码基因(TCRA或TRA,T cell receptor-alpha gene)通常会发生丢失(TREC,T cell receptor excision circle)。基于此,本研究针对肿瘤配对的全外显子组测序数据开发了一个名为T cell ExTRECT的T细胞比例估计工具。该工具的原理主要是通过检测TRA基因发生肿瘤体细胞拷贝数变化(RDR,read-depth ratio),进而直接定量T细胞的比例。局限性:不能区分发生新抗原反应的T细胞和检测克隆型(clonotype);只能应用于全外显子组测序,要求测序深度大于30x。
Abstract:
The immune microenvironment influences tumour evolution and can be both prognostic and predict response to immunotherapy. However, measurements of tumour infiltrating lymphocytes (TILs) are limited by a shortage of appropriate …
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The immune microenvironment influences tumour evolution and can be both prognostic and predict response to immunotherapy. However, measurements of tumour infiltrating lymphocytes (TILs) are limited by a shortage of appropriate data. Whole-exome sequencing (WES) of DNA is frequently performed to calculate tumour mutational burden and identify actionable mutations. Here we develop T cell exome TREC tool (T cell ExTRECT), a method for estimation of T cell fraction from WES samples using a signal from T cell receptor excision circle (TREC) loss during V(D)J recombination of the T cell receptor-α gene (TCRA (also known as TRA)). TCRA T cell fraction correlates with orthogonal TIL estimates and is agnostic to sample type. Blood TCRA T cell fraction is higher in females than in males and correlates with both tumour immune infiltrate and presence of bacterial sequencing reads. Tumour TCRA T cell fraction is prognostic in lung adenocarcinoma. Using a meta-analysis of tumours treated with immunotherapy, we show that tumour TCRA T cell fraction predicts immunotherapy response, providing value beyond measuring tumour mutational burden. Applying T cell ExTRECT to a multi-sample pan-cancer cohort reveals a high diversity of the degree of immune infiltration within tumours. Subclonal loss of 12q24.31-32, encompassing SPPL3, is associated with reduced TCRA T cell fraction. T cell ExTRECT provides a cost-effective technique to characterize immune infiltrate alongside somatic changes.
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568.
尹志
(2023-06-30 21:30):
#paper https://doi.org/10.1002/ange.202210001, Angewandte Chemie 134.40 (2022), A Carbon-Carbon Bond Cleavage-Based Prodrug Activation Strategy Applied to β-Lapachone for Cancer-Specific Targeting。基本过了一遍,特别有意思的工作。文章提出了一种新型的前药(prodrug)设计策略,利用C-C键断裂来生成父药(parent drug)。在文章中这个父药是β-Lapachone, 一种对胰腺癌和肺癌有靶向效果的药物分子。前药设计策略是靶向药设计的一种现代方法,它的思路是,很多药物直接服用或者使用对患者的毒性较高,因此治疗窗口就较小。而前药设计策略是,将父药包装成前药分子,然后通过前药分子的摄入进入体内,然后在到达靶点之后,通过某种方式,转变为父药,进而被激活,产生药物活性。这个过程降低了药物毒性的影响,延长了治疗窗口。传统上,前药激活的方式是通过断裂C-N/C-O键,但是很多可修饰基团没有C-N/C-O bond。作者的新策略是进行C-C bond的断裂,从而产生父药,从而产生药效。脑洞一下啊,今年初,张锋组的一篇工作,我之前在paper群有写,通过一种叫外胞质收缩注射系统的纳米机器,进行各种蛋白质负载的传递,我感觉和前药设计的思想很像啊,都是通过间接的方式,避开某种问题,实现最终效果,类似构建一套传递体系或者传递策略。这点上很值得借鉴。只能说,药物设计生物设计简直泰裤辣
Angewandte Chemie,
2022.
DOI: 10.1002/ange.202210001
Abstract:
Prodrugs are one of the most common strategies for the design of targeted anticancer agents. However, their application is often hampered by the modifiable groups available on parent drugs. Herein, …
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Prodrugs are one of the most common strategies for the design of targeted anticancer agents. However, their application is often hampered by the modifiable groups available on parent drugs. Herein, a carbon-carbon (C−C) bond cleavage-based prodrug activation strategy is reported, which was successfully used to design prodrugs of β-lapachone (β-lap), an ortho-quinone natural product without traditional modifiable groups for the construction of C−N/C−O bond cleavage-based prodrugs. The designed β-lap prodrug with a reactive oxygen species-specific trigger was quickly activated, releasing β-lap. It exerted anticancer efficacy via NAD(P)H:quinone oxidoreductase 1 (NQO1)-mediated futile redox cycling, resulting in potent cytotoxicity that was highly selective for NQO1-rich cancer cells over normal cells both in vitro and in vivo. This significantly amplified the therapeutic window of β-lap. This study provides a practical strategy for the design of prodrugs for parent drugs that do not contain traditional modifiable groups.
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569.
周周复始
(2023-06-30 20:39):
#paper 6-MONTH INFANT BRAIN MRI SEGMENTATION GUIDED BY 24-MONTH DATA USING CYCLE-CONSISTENT ADVERSARIAL NETWORKS.2020.doi: 10.1109/isbi45749.2020.9098515. 6个月左右白质和灰质之间的对比度极低,很难进行人工标注,训练标签的数量非常有限。因此,婴儿脑MRI的自动分割仍然具有一定的挑战性。但成人早期(如24个月)的图像的对比度相对较好,可以很容易地通过成熟的工具进行分割,例如FreeSurfer。因此,本文提出了一种利用24个月大的图像对6个月大的图像进行可靠的组织分割的方法。设计了一个3D-cycleGAN-Seg架构,通过在两个时间点之间转移外观来生成等强度相位的合成图像。为了保证6个月和24个月的图像组织分割的一致性,使用生成的分割的特征来指导生成器网络的训练。为了进一步提高合成图像的质量,提出了一种特征匹配损失,即计算真实图像和伪图像未配对分割特征之间的余弦距离。然后,利用转移的24个月的图像,在6个月的图像上联合训练分割模型。
Abstract:
Due to the extremely low intensity contrast between the white matter (WM) and the gray matter (GM) at around 6 months of age (the isointense phase), it is difficult for …
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Due to the extremely low intensity contrast between the white matter (WM) and the gray matter (GM) at around 6 months of age (the isointense phase), it is difficult for manual annotation, hence the number of training labels is highly limited. Consequently, it is still challenging to automatically segment isointense infant brain MRI. Meanwhile, the contrast of intensity images in the early adult phase, such as 24 months of age, is a relatively better, which can be easily segmented by the well-developed tools, e.g., FreeSurfer. Therefore, the question is how could we employ these high-contrast images (such as 24-month-old images) to guide the segmentation of 6-month-old images. Motivated by the above purpose, we propose a method to explore the 24-month-old images for a reliable tissue segmentation of 6-month-old images. Specifically, we design a 3D-cycleGAN-Seg architecture to generate synthetic images of the isointense phase by transferring appearances between the two time-points. To guarantee the tissue segmentation consistency between 6-month-old and 24-month-old images, we employ features from generated segmentations to guide the training of the generator network. To further improve the quality of synthetic images, we propose a feature matching loss that computes the cosine distance between unpaired segmentation features of the real and fake images. Then, the transferred of 24-month-old images is used to jointly train the segmentation model on the 6-month-old images. Experimental results demonstrate a superior performance of the proposed method compared with the existing deep learning-based methods.
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570.
哪有情可长
(2023-06-30 16:14):
#paper Characterization of novel loci controlling seed oil content in Brassica napus by marker metabolite-based multi-omics analysis,Genome biology, 19 June 2023, doi.org/10.1186/s13059-023-02984-z 文章利用广泛靶向代谢物分析共检测到2173种代谢物,对代谢物和油菜含油量进行相关性分析,最终鉴定到131个跟含油量高度相关的代谢物,并将代谢物作为含油量的代谢标志物。对131个含有代谢物进行全基因组关联分析,鉴定到446个mQTL位点,结合群体转录组关联分析,共鉴定到与含油量标志物显著关联的7316个基因,后面作者们有找到催化黄酮生物合成第一步反应的一个基因,对该基因进行后续验证。现在作物上数据整合的落脚点还得是找基因进行验证
Abstract:
BACKGROUND: Seed oil content is an important agronomic trait of Brassica napus (B. napus), and metabolites are considered as the bridge between genotype and phenotype for physical traits.RESULTS: Using a …
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BACKGROUND: Seed oil content is an important agronomic trait of Brassica napus (B. napus), and metabolites are considered as the bridge between genotype and phenotype for physical traits.RESULTS: Using a widely targeted metabolomics analysis in a natural population of 388 B. napus inbred lines, we quantify 2172 metabolites in mature seeds by liquid chromatography mass spectrometry, in which 131 marker metabolites are identified to be correlated with seed oil content. These metabolites are then selected for further metabolite genome-wide association study and metabolite transcriptome-wide association study. Combined with weighted correlation network analysis, we construct a triple relationship network, which includes 21,000 edges and 4384 nodes among metabolites, metabolite quantitative trait loci, genes, and co-expression modules. We validate the function of BnaA03.TT4, BnaC02.TT4, and BnaC05.UK, three candidate genes predicted by multi-omics analysis, which show significant impacts on seed oil content through regulating flavonoid metabolism in B. napus.CONCLUSIONS: This study demonstrates the advantage of utilizing marker metabolites integrated with multi-omics analysis to dissect the genetic basis of agronomic traits in crops.
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571.
Vincent
(2023-06-30 15:00):
#paper https://www.nature.com/articles/s41467-018-04608-8, Nature communication 2018, Exploring patterns enriched in a dataset with contrastive principal component analysis
PCA(主成分分析)能够将高维数据映射到低维,是最常用的数据探索和可视化工具。然而PCA(以及其他降维方法例如t-sne, umap)每次只能分析一个数据集。当处理多个数据集,尤其是寻找某数据集特有的信号时,使用PCA就需要人工比较不同数据集的投影来试图寻找数据集间的相似和不同点。这篇文章提出了解决此类问题的一种简单有效的降维方法:对比PCA。该方法旨在寻找一个投影,使得目标数据集和背景数据集的差距尽可能大,从而富集目标数据集特有的信号。该方法原理与实现和PCA类似,后续实验验证了其能有效发现那些被PCA忽视的目标数据集特有的信号。除此之外,文章还详述了该方法的理论基础和几何表示,并指出其可以运用在很多PCA的使用场景中。
Abstract:
Visualization and exploration of high-dimensional data is a ubiquitous challenge across disciplines. Widely used techniques such as principal component analysis (PCA) aim to identify dominant trends in one dataset. However, …
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Visualization and exploration of high-dimensional data is a ubiquitous challenge across disciplines. Widely used techniques such as principal component analysis (PCA) aim to identify dominant trends in one dataset. However, in many settings we have datasets collected under different conditions, e.g., a treatment and a control experiment, and we are interested in visualizing and exploring patterns that are specific to one dataset. This paper proposes a method, contrastive principal component analysis (cPCA), which identifies low-dimensional structures that are enriched in a dataset relative to comparison data. In a wide variety of experiments, we demonstrate that cPCA with a background dataset enables us to visualize dataset-specific patterns missed by PCA and other standard methods. We further provide a geometric interpretation of cPCA and strong mathematical guarantees. An implementation of cPCA is publicly available, and can be used for exploratory data analysis in many applications where PCA is currently used.
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572.
庞庞
(2023-06-30 13:59):
#paper Performing group-level functional image analyses based on homologous functional regions mapped in individuals https://doi.org/10.1371/journal.pbio.2007032 大脑功能区域的大小、形状、位置和连接模式在个体之间可能存在巨大差异。 虽然功能组织的个体间差异已得到广泛认可,但迄今为止,功能神经影像研究的标准程序仍然依赖于将不同受试者的数据与基于整体大脑形态的名义“平均”大脑进行对齐。 研究者开发了一种方法来可靠地识别每个个体的同源功能区域,并证明基于这些同源功能区域对齐数据可以显着改善静息状态功能连接、任务功能磁共振成像激活和大脑行为关联的研究。 此外,我们发现大脑功能区域的大小、位置和连接性方面的个体差异是可分离的。
Abstract:
Functional MRI (fMRI) studies have traditionally relied on intersubject normalization based on global brain morphology, which cannot establish proper functional correspondence between subjects due to substantial intersubject variability in functional …
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Functional MRI (fMRI) studies have traditionally relied on intersubject normalization based on global brain morphology, which cannot establish proper functional correspondence between subjects due to substantial intersubject variability in functional organization. Here, we reliably identified a set of discrete, homologous functional regions in individuals to improve intersubject alignment of fMRI data. These functional regions demonstrated marked intersubject variability in size, position, and connectivity. We found that previously reported intersubject variability in functional connectivity maps could be partially explained by variability in size and position of the functional regions. Importantly, individual differences in network topography are associated with individual differences in task-evoked activations, suggesting that these individually specified regions may serve as the "localizer" to improve the alignment of task-fMRI data. We demonstrated that aligning task-fMRI data using the regions derived from resting state fMRI may lead to increased statistical power of task-fMRI analyses. In addition, resting state functional connectivity among these homologous regions is able to capture the idiosyncrasies of subjects and better predict fluid intelligence (gF) than connectivity measures derived from group-level brain atlases. Critically, we showed that not only the connectivity but also the size and position of functional regions are related to human behavior. Collectively, these findings suggest that identifying homologous functional regions across individuals can benefit a wide range of studies in the investigation of connectivity, task activation, and brain-behavior associations.
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573.
姗姗来迟
(2023-06-30 13:25):
#paper Arabic Dialect Identification with a Few Labeled Examples Using Generative Adversarial Networks
https://aclanthology.org/2022.aacl-main.16.pdf
考虑到在处理阿拉伯方言(DA)变化时引入的挑战和复杂性,基于Transformer的模型,例如BERT,在处理DA识别任务方面优于其他模型。然而,要对这些模型进行微调,需要大量的语料库。为一些阿拉伯语方言课程获取大量高质量的示例是具有挑战性和耗时的。
该论文扩展了基于Transformer的模型(ARBERT和MARBERT)使用 半监督生成对抗网络(SS-GAN)在生成对抗设置中使用未分类数据。模型能够为阿拉伯语方言样本 生成高质量的嵌入,并帮助模型更好地泛化下游分类任务。
ACL Anthology,
2022.
Abstract:
Given the challenges and complexities introduced while dealing with Dialect Arabic (DA) variations, Transformer based models, e.g., BERT, outperformed other models in dealing with the DA identification task. However, to …
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Given the challenges and complexities introduced while dealing with Dialect Arabic (DA) variations, Transformer based models, e.g., BERT, outperformed other models in dealing with the DA identification task. However, to fine-tune these models, a large corpus is required. Getting a large number high quality labeled examples for some Dialect Arabic classes is challenging and time-consuming. In this paper, we address the Dialect Arabic Identification task. We extend the transformer-based models, ARBERT and MARBERT, with unlabeled data in a generative adversarial setting using Semi-Supervised Generative Adversarial Networks (SS-GAN). Our model enabled producing high-quality embeddings for the Dialect Arabic examples and aided the model to better generalize for the downstream classification task given few labeled examples. Experimental results showed that our model reached better performance and faster convergence when only a few labeled examples are available.
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574.
Spring
(2023-06-30 13:17):
#paper Parabacteroides distasonis uses dietary inulin to suppress NASH via its metabolite pentadecanoic acid
doi: 10.1038/s41564-023-01418-7
① 小鼠模型中,菊粉比纤维素能更有效地抑制非酒精性脂肪肝炎(NASH)进展;② 用稳定同位素探测法(13C标记的菊粉)结合宏基因组测序和代谢组分析,发现菊粉可改变肠道菌群(富集潜在有益菌、抑制潜在致病菌)并可被特定肠菌吸收,其中被菊粉富集的狄氏副拟杆菌(Pd)可活跃地利用菊粉生成脂肪酸十五烷酸;③ 菊粉、Pd或十五烷酸可恢复NASH小鼠模型的肠道屏障功能,从而减少血清脂多糖和肝脏促炎细胞因子表达,对NASH发挥保护作用。
Abstract:
Non-alcoholic steatohepatitis (NASH) is the severe form of non-alcoholic fatty liver disease, and is characterized by liver inflammation and fat accumulation. Dietary interventions, such as fibre, have been shown to …
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Non-alcoholic steatohepatitis (NASH) is the severe form of non-alcoholic fatty liver disease, and is characterized by liver inflammation and fat accumulation. Dietary interventions, such as fibre, have been shown to alleviate this metabolic disorder in mice via the gut microbiota. Here, we investigated the mechanistic role of the gut microbiota in ameliorating NASH via dietary fibre in mice. Soluble fibre inulin was found to be more effective than insoluble fibre cellulose to suppress NASH progression in mice, as shown by reduced hepatic steatosis, necro-inflammation, ballooning and fibrosis. We employed stable isotope probing to trace the incorporation of C-inulin into gut bacterial genomes and metabolites during NASH progression. Shotgun metagenome sequencing revealed that the commensal Parabacteroides distasonis was enriched by C-inulin. Integration of C-inulin metagenomes and metabolomes suggested that P. distasonis used inulin to produce pentadecanoic acid, an odd-chain fatty acid, which was confirmed in vitro and in germ-free mice. P. distasonis or pentadecanoic acid was protective against NASH in mice. Mechanistically, inulin, P. distasonis or pentadecanoic acid restored gut barrier function in NASH models, which reduced serum lipopolysaccharide and liver pro-inflammatory cytokine expression. Overall this shows that gut microbiota members can use dietary fibre to generate beneficial metabolites to suppress metabolic disease.
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575.
张浩彬
(2023-06-30 11:45):
#paper The Capacity and Robustness Trade-off: Revisiting the Channel Independent Strategy for Multivariate Time Series Forecasting doi:
https://doi.org/10.48550/arXiv.2304.05206Focus to learn more
专门研究了针对多元时间序列的预测问题,探讨了使用独立预测以及联合预测的差异,证明了由于分布偏移的存在,独立预测的方法更好,应为其更加有利于缓解分布偏移的问题,提高模型的繁华性。并且文章证明了独立预测和联合预测,是一种模型容量和模型鲁棒性的权衡。随州论文提出了包括正则化,低秩分解、采用MAE代替MSE,调整序列长度等方法提高联合预测的精度
arXiv,
2023.
DOI: 10.48550/arXiv.2304.05206
Abstract:
Multivariate time series data comprises various channels of variables. The multivariate forecasting models need to capture the relationship between the channels to accurately predict future values. However, recently, there has …
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Multivariate time series data comprises various channels of variables. The multivariate forecasting models need to capture the relationship between the channels to accurately predict future values. However, recently, there has been an emergence of methods that employ the Channel Independent (CI) strategy. These methods view multivariate time series data as separate univariate time series and disregard the correlation between channels. Surprisingly, our empirical results have shown that models trained with the CI strategy outperform those trained with the Channel Dependent (CD) strategy, usually by a significant margin. Nevertheless, the reasons behind this phenomenon have not yet been thoroughly explored in the literature. This paper provides comprehensive empirical and theoretical analyses of the characteristics of multivariate time series datasets and the CI/CD strategy. Our results conclude that the CD approach has higher capacity but often lacks robustness to accurately predict distributionally drifted time series. In contrast, the CI approach trades capacity for robust prediction. Practical measures inspired by these analyses are proposed to address the capacity and robustness dilemma, including a modified CD method called Predict Residuals with Regularization (PRReg) that can surpass the CI strategy. We hope our findings can raise awareness among researchers about the characteristics of multivariate time series and inspire the construction of better forecasting models.
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576.
李翛然
(2023-06-27 14:00):
#paper Reduced hepatocyte mitophagy is an early feature of NAFLD pathogenesis and hastens the onset of steatosis, inflammation and fibrosis doi: 10.21203/rs.3.rs-2469234/v1. 这个文章很有意思。非酒精性脂肪性肝病(NAFLD)是一种全球流行性慢性疾病,是由肝细胞中肝脏脂肪过度堆积导致,因此也称为肝脏脂肪变性。临床范围包括,包括肝脂肪变性(NAFL,超过5%的肝细胞中脂肪堆积)、非酒精性脂肪性肝炎(NASH,其特征是存在肝细胞损伤、纤维化炎症等)、肝硬化和肝细胞癌。NAFLD与代谢综合征的特征密切相关,包括肥胖、胰岛素抵抗、高血糖、2型糖尿病和血脂异常。 现在基本上 35岁以上,有轻度的高血脂的人群或多或少都会出现脂肪肝。
传统的认为 脂肪肝都是吃的和代谢的问题,但是随着我们自己团队对于衰老模型的认识逐渐加深,以及各方的了解,其实非细菌性引起的各项炎症,也是引发癌症,NASH这种隐性疾病的元凶。 这一点和中医不谋而合,特别想中医上说的湿气重。 其实就是体内炎症无法清除干净的问题。
这两年真的是生物的好时候来了啊!生物信息学越来越多的应用,最终返璞归真,期待着采用天然产物来控制疾病到来的那一天。
Abstract:
Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of pathologies that includes steatosis, steatohepatitis (NASH) and fibrosis and is strongly associated with insulin resistance and type 2 diabetes. Changes in …
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Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of pathologies that includes steatosis, steatohepatitis (NASH) and fibrosis and is strongly associated with insulin resistance and type 2 diabetes. Changes in mitochondrial function are implicated in the pathogenesis of NAFLD, particularly in the transition from steatosis to NASH. Mitophagy is a mitochondrial quality control mechanism that allows for the selective removal of damaged mitochondria from the cell via the autophagy pathway. While past work demonstrated a negative association between liver fat content and rates of mitophagy, when changes in mitophagy occur during the pathogenesis of NAFLD and whether such changes contribute to the primary endpoints associated with the disease are currently poorly defined. We therefore undertook the studies described here to establish when alterations in mitophagy occur during the pathogenesis of NAFLD, as well as to determine the effects of genetic inhibition of mitophagy via conditional deletion of a key mitophagy regulator, PARKIN, on the development of steatosis, insulin resistance, inflammation and fibrosis. We find that loss of mitophagy occurs early in the pathogenesis of NAFLD and that loss of PARKIN hastens the onset but not severity of key NAFLD disease features. These observations suggest that loss of mitochondrial quality control in response to nutritional stress may contribute to mitochondrial dysfunction and the pathogenesis of NAFLD.
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577.
符毓
(2023-06-26 23:22):
#paper doi:10.1038/171737a0 Nature, 2014, Passive radiative cooling below ambient air temperature under direct sunlight。辐射制冷材料通过反射包括紫外线、可视光、近红外和中红外等让物体温度低于环境温度。本文通过7层材料构成的冷却材料,首次在日间成功实现辐射制冷。在850W/平方米的日照下实现4.9度的降温
Abstract:
No abstract available.
578.
DeDe宝
(2023-06-25 23:08):
#paper doi https://doi.org/10.1038/s41467-023-35967-6,Nature Communications,2023, Goal-oriented representations in the human hippocampus during planning and navigation.在之前的研究中,海马被认为与长时记忆、位置表征相关,然而,最近认知和系统神经科学的研究表明,海马可能通过形成认知地图支持计划、想象和导航。在本研究中,研究者探究人类在目标导向导航任务期间的海马活动模式,以研究如何将上下文和目标纳入导航计划的构建和执行中。在计划阶段,相同背景和目标的路线之间的海马模式相似性增强。在导航阶段,海马前瞻性激活。
Abstract:
Recent work in cognitive and systems neuroscience has suggested that the hippocampus might support planning, imagination, and navigation by forming cognitive maps that capture the abstract structure of physical spaces, …
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Recent work in cognitive and systems neuroscience has suggested that the hippocampus might support planning, imagination, and navigation by forming cognitive maps that capture the abstract structure of physical spaces, tasks, and situations. Navigation involves disambiguating similar contexts, and the planning and execution of a sequence of decisions to reach a goal. Here, we examine hippocampal activity patterns in humans during a goal-directed navigation task to investigate how contextual and goal information are incorporated in the construction and execution of navigational plans. During planning, hippocampal pattern similarity is enhanced across routes that share a context and a goal. During navigation, we observe prospective activation in the hippocampus that reflects the retrieval of pattern information related to a key-decision point. These results suggest that, rather than simply representing overlapping associations or state transitions, hippocampal activity patterns are shaped by context and goals.
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579.
惊鸿
(2023-06-25 16:56):
#paper https://doi.org/10.1021/acssynbio.3c00216 Immortalized Bovine Satellite Cells for Cultured Meat Applications 为了使培养肉大规模成功,来自食品相关物种的肌肉细胞必须以快速可靠的方式在体外扩增,以每年产生数百万公吨的生物质。为了实现这一目标,遗传永生化细胞比原代细胞具有实质性的好处,包括快速生长、逃离细胞衰老以及一致的起始细胞群进行生产。在这里,我们通过牛端粒酶逆转录酶(TERT)和细胞周期蛋白依赖性激酶4(CDK4)的组成表达开发遗传永生化的牛卫星细胞(iBSC)。这些细胞在发表时实现了超过120倍的倍增,并保持其肌源分化的能力。因此,它们为该领域提供了有价值的工具,使进一步的研究和开发能够推进培养肉。
Abstract:
For cultured meat to succeed at scale, muscle cells from food-relevant species must be expanded in vitro in a rapid and reliable manner to produce millions of metric tons of …
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For cultured meat to succeed at scale, muscle cells from food-relevant species must be expanded in vitro in a rapid and reliable manner to produce millions of metric tons of biomass annually. Toward this goal, genetically immortalized cells offer substantial benefits over primary cells, including rapid growth, escape from cellular senescence, and consistent starting cell populations for production. Here, we develop genetically immortalized bovine satellite cells (iBSCs) via constitutive expression of bovine Telomerase reverse transcriptase (TERT) and Cyclin-dependent kinase 4 (CDK4). These cells achieve over 120 doublings at the time of publication and maintain their capacity for myogenic differentiation. They therefore offer a valuable tool to the field, enabling further research and development to advance cultured meat.
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580.
徐炳祥
(2023-06-25 09:39):
#paper doi:10.1186/s13059-023-02970-5 Genome Biology, 2023, Genomic and epigenomic determinants of heat stress‑induced transcriptional memory in Arabidopsis。热刺激是植物细胞经常面临的环境压力,能引起细胞内大规模转录响应。热刺激诱导的转录记忆是其中重要的调控模式,然而其形成机制尚不清楚。本文结合前后两次热刺激后的HSFA2和HSFA3结合位点、H3K4me3信号分布、ATAC-seq标记的染色质开放性和基因表达谱数据,从表观遗传层面对该问题进行了探讨。结果显示具有热刺激诱导记忆行为的基因有特征性的热刺激因子结合模式、在常温下有低表达水平但有开放的启动子区域,刺激后富集H3K4me3信号等特征。本文为刺激反应的表观遗传研究提供了一个可供借鉴的范式。
Abstract:
BACKGROUND: Transcriptional regulation is a key aspect of environmental stress responses. Heat stress induces transcriptional memory, i.e., sustained induction or enhanced re-induction of transcription, that allows plants to respond more …
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BACKGROUND: Transcriptional regulation is a key aspect of environmental stress responses. Heat stress induces transcriptional memory, i.e., sustained induction or enhanced re-induction of transcription, that allows plants to respond more efficiently to a recurrent HS. In light of more frequent temperature extremes due to climate change, improving heat tolerance in crop plants is an important breeding goal. However, not all heat stress-inducible genes show transcriptional memory, and it is unclear what distinguishes memory from non-memory genes. To address this issue and understand the genome and epigenome architecture of transcriptional memory after heat stress, we identify the global target genes of two key memory heat shock transcription factors, HSFA2 and HSFA3, using time course ChIP-seq.RESULTS: HSFA2 and HSFA3 show near identical binding patterns. In vitro and in vivo binding strength is highly correlated, indicating the importance of DNA sequence elements. In particular, genes with transcriptional memory are strongly enriched for a tripartite heat shock element, and are hallmarked by several features: low expression levels in the absence of heat stress, accessible chromatin environment, and heat stress-induced enrichment of H3K4 trimethylation. These results are confirmed by an orthogonal transcriptomic data set using both de novo clustering and an established definition of memory genes.CONCLUSIONS: Our findings provide an integrated view of HSF-dependent transcriptional memory and shed light on its sequence and chromatin determinants, enabling the prediction and engineering of genes with transcriptional memory behavior.
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