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501.
(2023-02-28 23:07):
#paper DOI:10.1080/19490976.2021.2022407. Epigenetic regulation by gut microbiota.肠道微生物最近比较火,因为它们可以指导宿主体内健康和疾病的环境刺激。虽然已经在局部肠细胞和外周组织中描述了微生物群敏感的表观遗传机制,但还需要进一步的研究来完全破译宿主和微生物群之间的复杂关系。这篇综述从连接微生物群和哺乳动物细胞的表观遗传调控、微生物代谢物作为表观遗传底物和酶调节因子、微生物群在稳态和炎症过程中指导DNA甲基化模式、宿主-微生物通过组蛋白修饰相互作用、SCFAs对免疫细胞的调节作用、非共价修饰等方面强调了目前对肠道微生物群表观遗传调控的理解,以及这些发现在指导治疗方法以预防或对抗由微生物-宿主相互作用受损引起的疾病方面的重要意义。
IF:12.200Q1 Gut microbes, 2022 Jan-Dec. DOI: 10.1080/19490976.2021.2022407 PMID: 35000562
Abstract:
The gastrointestinal tract is continuously exposed to trillions of commensal microbes, collectively termed the microbiota, which are environmental stimuli that can direct health and disease within the host. In addition … >>>
The gastrointestinal tract is continuously exposed to trillions of commensal microbes, collectively termed the microbiota, which are environmental stimuli that can direct health and disease within the host. In addition to well-established bacterial sensing pathways, microbial signals are also integrated through epigenetic modifications that calibrate the transcriptional program of host cells without altering the underlying genetic code. Microbiota-sensitive epigenetic changes include modifications to the DNA or histones, as well as regulation of non-coding RNAs. While microbiota-sensitive epigenetic mechanisms have been described in both local intestinal cells and as well in peripheral tissues, further research is required to fully decipher the complex relationship between the host and microbiota. This Review highlights current understandings of epigenetic regulation by gut microbiota and important implications of these findings in guiding therapeutic approaches to prevent or combat diseases driven by impaired microbiota-host interactions. <<<
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502.
Ricardo (2023-02-28 22:09):
#paper doi:https://doi.org/10.1016/0730-725X(90)90056-8 Simulation of the influence of magnetic field inhomogeneity and distortion correction in MR imaging. 这篇论文比较老了,1990年发表的。作者在这篇论文中描述了一个用于模拟和校正由静态和梯度磁场中干扰MRI体素位置和信号编码的技术。数学原理其实不复杂,主要思想就是确定映射到目标图像的某个体素左右邻边在源图像上的位置,从而确定在源图像上体素的采样范围,根据线性插值的方法对采样范围内的体素进行加权。本来我想把这个模型用到我自己的工作中,但是思考了好几天发现这个过程貌似无法在模型中传递梯度,遂作罢。
Abstract:
We describe a technique for simulation and correction of the effects of an arbitrary distribution of undesired components of the static and gradient magnetic fields. This technique is applicable to … >>>
We describe a technique for simulation and correction of the effects of an arbitrary distribution of undesired components of the static and gradient magnetic fields. This technique is applicable to direct Fourier NMR imaging. The mathematical basis and details of this technique are fully described. Computer simulation demonstrates the effectiveness of this method. <<<
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503.
muton (2023-02-28 22:04):
#paper DOI: 10.21203/rs.3.rs-2540186/v1 Sleep loss diminishes hippocampal reactivation and replay睡眠有助于记忆,如果学习后立即剥夺睡眠对随后的记忆储存有负面影响。一些著名的假说认为,在睡眠期间发生的离线记忆巩固过程中,海马的尖波涟漪(SWRs)以及清醒时的神经元模式的同时重新激活和记忆重放起着核心作用。然而,当动物被剥夺睡眠时,SWRs、重新激活和重放是如何被影响的,人们对此所知甚少。作者对大鼠海马CA1神经元进行了长时间(约12小时)、高密度的硅探针记录,在这些动物在暴露于一个新的迷宫环境后,一些进入睡眠状态,一些被剥夺睡眠。我们发现,在睡眠剥夺期间,SWRs显示出持续的活动率,类似于或高于自然睡眠,但尖锐波的振幅下降,同时波纹的频率更高。此外,虽然海马锥体细胞在睡眠期间显示出对数正态分布的放电频率,但这些分布是负偏斜的,在睡眠剥夺期间,锥体细胞和中间神经元的平均放电频率都较高。然而,在SWRs期间,两组的放电频率非常相似。尽管两组都有大量的SWRs,并有强烈的放电活动,但我们发现,与睡眠剥夺相比,神经元的重新激活在睡眠剥夺期间要么完全没有,要么明显减少。有趣的是,在恢复睡眠后,重新激活部分又出现,但未能达到自然睡眠的特征水平。同样,与自然睡眠相比,在睡眠剥夺和恢复性睡眠期间,重放的数量明显减少。这些结果为睡眠损失对海马功能的负面影响提供了一个网络层面的解释,并证明睡眠损失通过导致SWRs的数量与这些事件中发生的记忆重放和重新激活之间的分离来影响记忆储存。
Abstract:
Memories benefit from sleep, and sleep loss immediately following learning has a negative impact on subsequent memory storage. Several prominent hypotheses ascribe a central role to hippocampal sharp-wave ripples (SWRs), … >>>
Memories benefit from sleep, and sleep loss immediately following learning has a negative impact on subsequent memory storage. Several prominent hypotheses ascribe a central role to hippocampal sharp-wave ripples (SWRs), and the concurrent reactivation and replay of neuronal patterns from waking experience, in the offline memory consolidation process that occurs during sleep. However, little is known about how SWRs, reactivation, and replay are affected when animals are subjected to sleep deprivation. We performed long duration (~12 h), high-density silicon probe recordings from rat hippocampal CA1 neurons, in animals that were either sleeping or sleep deprived following exposure to a novel maze environment. We found that SWRs showed a sustained rate of activity during sleep deprivation, similar to or higher than in natural sleep, but with decreased amplitudes for the sharp-waves combined with higher frequencies for the ripples. Furthermore, while hippocampal pyramidal cells showed a log-normal distribution of firing rates during sleep, these distributions were negatively skewed with a higher mean firing rate in both pyramidal cells and interneurons during sleep deprivation. During SWRs, however, firing rates were remarkably similar between both groups. Despite the abundant quantity of SWRs and the robust firing activity during these events in both groups, we found that reactivation of neurons was either completely abolished or significantly diminished during sleep deprivation compared to sleep. Interestingly, reactivation partially rebounded upon recovery sleep, but failed to reach the levels characteristic of natural sleep. Similarly, the number of replays were significantly lower during sleep deprivation and recovery sleep compared to natural sleep. These results provide a network-level account for the negative impact of sleep loss on hippocampal function and demonstrate that sleep loss impacts memory storage by causing a dissociation between the amount of SWRs and the replays and reactivations that take place during these events. <<<
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504.
尹志 (2023-02-28 21:51):
#paper https://doi.org/10.48550/arXiv.2203.17003 ICML, 2022, Equivariant Diffusion for Molecule Generation in 3D。扩散模型在各个领域发展极其迅速。除了图形图像,其触角已经扩展到生物制药、材料科学领域。本文就是一篇使用扩散模型进行3D分子生成的文章。作者提出了一种等变扩散模型,其中的等变网络能够很好的同时处理原子坐标这样的连续变量和原子类型这样的离散变量。该工作在QM9和GEOM两个典型的数据集上取得了sota的性能,是将等变性引入扩散模型的开篇工作之一。
Abstract:
This work introduces a diffusion model for molecule generation in 3D that is equivariant to Euclidean transformations. Our E(3) Equivariant Diffusion Model (EDM) learns to denoise a diffusion process with … >>>
This work introduces a diffusion model for molecule generation in 3D that is equivariant to Euclidean transformations. Our E(3) Equivariant Diffusion Model (EDM) learns to denoise a diffusion process with an equivariant network that jointly operates on both continuous (atom coordinates) and categorical features (atom types). In addition, we provide a probabilistic analysis which admits likelihood computation of molecules using our model. Experimentally, the proposed method significantly outperforms previous 3D molecular generative methods regarding the quality of generated samples and efficiency at training time. <<<
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505.
林海onrush (2023-02-28 21:45):
#paper,doi: https://doi.org/10.1038/s41586-023-05859-2,Continuous Symmetry Breaking in a Two-dimensional Rydberg Array,,自发对称性破坏是对物质相位及其相关跃迁进行分类的基础。被打破的潜在对称性的性质决定了相的许多定性特性;离散与连续对称性破坏的情况说明了这一点。与离散情况相反,连续对称性的破坏导致无间隙Goldstone模式的出现,例如控制有序相的热力学稳定性.作者利用可编程的里德伯量子模拟器实现了二维偶极XY模型,展示了XY铁磁体和XY反铁磁体相关低温态的绝热制备。在铁磁情况下,表征了长程XY阶的存在。这项工作对XY相互作用的多体物理学做出了贡献,补充了最近利用里德伯-封锁机制实现表现出离散自旋旋转对称性的Ising型相互作用的工作。该文近期被收录于nature,也证实了工作的严谨和创新。
IF:50.500Q1 Nature, 2023-04. DOI: 10.1038/s41586-023-05859-2 PMID: 36848931
Abstract:
Spontaneous symmetry breaking underlies much of our classification of phases of matter and their associated transitions. The nature of the underlying symmetry being broken determines many of the qualitative properties … >>>
Spontaneous symmetry breaking underlies much of our classification of phases of matter and their associated transitions. The nature of the underlying symmetry being broken determines many of the qualitative properties of the phase; this is illustrated by the case of discrete versus continuous symmetry breaking. Indeed, in contrast to the discrete case, the breaking of a continuous symmetry leads to the emergence of gapless Goldstone modes controlling, for instance, the thermodynamic stability of the ordered phase. Here, we realize a two-dimensional dipolar XY model that shows a continuous spin-rotational symmetry using a programmable Rydberg quantum simulator. We demonstrate the adiabatic preparation of correlated low-temperature states of both the XY ferromagnet and the XY antiferromagnet. In the ferromagnetic case, we characterize the presence of a long-range XY order, a feature prohibited in the absence of long-range dipolar interaction. Our exploration of the many-body physics of XY interactions complements recent works using the Rydberg-blockade mechanism to realize Ising-type interactions showing discrete spin rotation symmetry. <<<
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506.
Arwen (2023-02-28 21:39):
#paper https://doi.org/10.1038/s41467-023-36605-x Multivariate genomic architecture of cortical thickness and surface area at multiple levels of analysis 最近在影像遗传学方面的工作表明,皮层区域内皮层厚度(CT)和表面积(SA)的遗传重叠程度很高。该研究通过应用基因组结构方程模型(Genomic SEM)对这一遗传关系的多变量系统进行建模,并对CT和SA的五个脑部基因组因素以及一个捕捉所有脑区遗传重叠的一般因素进行解析。我们通过证明该模型在独立样本中的普遍性来验证这些因素,并表明这些因素与脑皮层的生物和功能相关分区相一致。我们应用分层基因组SEM来确定特定类别的基因(如神经元细胞类型),这些基因与脑区特定亚群的多态性成正比关系。最后,研究了与精神和认知相关的遗传关系,发现认知功能的广泛与SA的一般因素有关,而与精神方面的关系不明显。这些分析提供了脑皮层两个关键特征的多变量基因组结构的关键见解。
IF:14.700Q1 Nature communications, 2023-02-20. DOI: 10.1038/s41467-023-36605-x PMID: 36806290
Abstract:
Recent work in imaging genetics suggests high levels of genetic overlap within cortical regions for cortical thickness (CT) and surface area (SA). We model this multivariate system of genetic relationships … >>>
Recent work in imaging genetics suggests high levels of genetic overlap within cortical regions for cortical thickness (CT) and surface area (SA). We model this multivariate system of genetic relationships by applying Genomic Structural Equation Modeling (Genomic SEM) and parsimoniously define five genomic brain factors underlying both CT and SA along with a general factor capturing genetic overlap across all brain regions. We validate these factors by demonstrating the generalizability of the model to a semi-independent sample and show that the factors align with biologically and functionally relevant parcellations of the cortex. We apply Stratified Genomic SEM to identify specific categories of genes (e.g., neuronal cell types) that are disproportionately associated with pleiotropy across specific subclusters of brain regions, as indexed by the genomic factors. Finally, we examine genetic associations with psychiatric and cognitive correlates, finding that broad aspects of cognitive function are associated with a general factor for SA and that psychiatric associations are null. These analyses provide key insights into the multivariate genomic architecture of two critical features of the cerebral cortex. <<<
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507.
白鸟 (2023-02-28 21:23):
#paper doi:https://doi.org/10.1038/s41587-021-00895-7, 2021, Nonvolatile Memory Based on Nonlinear Magnetoelectric Effects. 单细胞多模态检测技术:通过各种实验技术进行多模态检测,即在同一个细胞中同时探测不同的分子特征,在高分辨率下,成千上万的细胞拥有越来越多的分子维度,包括基因组、转录组和表观遗传修饰。虽然没有一个单一的“全能”技术可以完全捕捉到复杂的分子机制,但这些数据有可能提供一个基本的生物过程,有机会从描述性的 "快照 "向对基因调控的机械性理解推进。 意义:单细胞多模态检测技术的发展为研究细胞异质性的多个维度提供了强有力的工具,使我们对发育、组织稳态和疾病有了新的认识。通过结合关于分子层之间层次关系的先验知识(即生物学的中心法则),多模式分析将在识别基因调控网络中事件的因果链方面发挥重要作用。 挑战:设计适当的策略,将不同模式的数据联系起来。术语 "数据整合 "(data integration)被用来描述这项工作,这个定义很广泛,从单个组学数据集的批量校正到染色质可及性和遗传变异与转录的关联。 三种类型的数据整合策略:基因组特征作为锚点(水平整合);细胞为锚(垂直整合);高维空间没有锚点(对角线整合); 展望:回顾了数据整合策略的既定原则、局限性,尽管现有的整合策略利用了类似的数学思想,但它们通常有不同的目标,并依赖于不同的原则和假设。因此,需要新的定义和概念,以使单细胞数据整合技术具有本身的背景性,并能开发新的方法。
IF:33.100Q1 Nature biotechnology, 2021-10. DOI: 10.1038/s41587-021-00895-7 PMID: 33941931
Abstract:
The development of single-cell multimodal assays provides a powerful tool for investigating multiple dimensions of cellular heterogeneity, enabling new insights into development, tissue homeostasis and disease. A key challenge in … >>>
The development of single-cell multimodal assays provides a powerful tool for investigating multiple dimensions of cellular heterogeneity, enabling new insights into development, tissue homeostasis and disease. A key challenge in the analysis of single-cell multimodal data is to devise appropriate strategies for tying together data across different modalities. The term 'data integration' has been used to describe this task, encompassing a broad collection of approaches ranging from batch correction of individual omics datasets to association of chromatin accessibility and genetic variation with transcription. Although existing integration strategies exploit similar mathematical ideas, they typically have distinct goals and rely on different principles and assumptions. Consequently, new definitions and concepts are needed to contextualize existing methods and to enable development of new methods. <<<
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508.
LXJ (2023-02-28 21:22):
#paper DOI : 10.3390/vaccines11020408 Innate and Adaptive Immunity during SARS-CoV-2 Infection: Biomolecular Cellular Markers and Mechanisms 2019年冠状病毒(新冠肺炎)大流行是由一种ssRNA严重急性呼吸综合征冠状病毒2(SARS-CoV-2)引起的。然而,其他人类冠状病毒(hCoV)也存在。历史上的大流行病包括天花和流感,通过有效地针对宿主免疫系统的反应,利用有效的治疗方法来减轻总体疾病负担。免疫系统由初级/次级淋巴结构组成,最初有八种免疫细胞类型,以及许多其他亚型,利用细胞信号级联穿过细胞膜,有助于清除致病蛋白。讨论的其他蛋白质包括分化簇(CD)标记物、主要组织相容性复合物(MHC)、多效性白细胞介素(IL)和趋化因子(CXC)。宿主免疫的历史概念是先天和适应性免疫系统。适应性免疫系统由T细胞、B细胞和抗体代表。先天免疫系统由巨噬细胞、中性粒细胞、树突状细胞和补体系统组成。其他病毒可以影响和调节细胞周期进展,例如,在包括人乳头瘤病毒(HPV:宫颈癌)、EB病毒(EBV:淋巴瘤)、乙型肝炎和丙型肝炎(HB/HC:肝细胞癌)和人T细胞白血病病毒-1(T细胞白血病)的癌症中。细菌感染也会增加患癌症的风险(例如幽门螺杆菌)。病毒和细菌因素可导致发病率和死亡率,并通过影响宿主免疫反应在临床和社区环境中传播。因此,将单细胞测序的进展与其他实验室技术结合起来,有助于深入了解免疫细胞特征。这些发展提供了与自身免疫性疾病重叠的更好的清晰度和理解,这些疾病可能受到先天性B细胞(B1+或边缘区细胞)或对SARS-CoV-2感染和其他病理的适应性T细胞反应的影响。因此,这篇综述首先介绍了宿主呼吸道感染,然后检查了宝贵的细胞信使蛋白和个体免疫细胞标记物。
IF:5.200Q1 Vaccines, 2023-Feb-10. DOI: 10.3390/vaccines11020408 PMID: 36851285
Abstract:
The coronavirus 2019 (COVID-19) pandemic was caused by a positive sense single-stranded RNA (ssRNA) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, other human coronaviruses (hCoVs) exist. Historical pandemics include … >>>
The coronavirus 2019 (COVID-19) pandemic was caused by a positive sense single-stranded RNA (ssRNA) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, other human coronaviruses (hCoVs) exist. Historical pandemics include smallpox and influenza, with efficacious therapeutics utilized to reduce overall disease burden through effectively targeting a competent host immune system response. The immune system is composed of primary/secondary lymphoid structures with initially eight types of immune cell types, and many other subtypes, traversing cell membranes utilizing cell signaling cascades that contribute towards clearance of pathogenic proteins. Other proteins discussed include cluster of differentiation (CD) markers, major histocompatibility complexes (MHC), pleiotropic interleukins (IL), and chemokines (CXC). The historical concepts of host immunity are the innate and adaptive immune systems. The adaptive immune system is represented by T cells, B cells, and antibodies. The innate immune system is represented by macrophages, neutrophils, dendritic cells, and the complement system. Other viruses can affect and regulate cell cycle progression for example, in cancers that include human papillomavirus (HPV: cervical carcinoma), Epstein-Barr virus (EBV: lymphoma), Hepatitis B and C (HB/HC: hepatocellular carcinoma) and human T cell Leukemia Virus-1 (T cell leukemia). Bacterial infections also increase the risk of developing cancer (e.g., ). Viral and bacterial factors can cause both morbidity and mortality alongside being transmitted within clinical and community settings through affecting a host immune response. Therefore, it is appropriate to contextualize advances in single cell sequencing in conjunction with other laboratory techniques allowing insights into immune cell characterization. These developments offer improved clarity and understanding that overlap with autoimmune conditions that could be affected by innate B cells (B1 or marginal zone cells) or adaptive T cell responses to SARS-CoV-2 infection and other pathologies. Thus, this review starts with an introduction into host respiratory infection before examining invaluable cellular messenger proteins and then individual immune cell markers. <<<
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509.
惊鸿 (2023-02-28 21:15):
#paper DOI : 10.1021/acsnano.2c10477 Floating Seawater Splitting Device Based on NiFeCrMo Metal Hydroxide Electrocatalyst and Perovskite/Silicon Tandem Solar Cells 海水光伏制氢意义重大。太阳能驱动海水电解面临的析氯反应竞争、氯化物腐蚀、催化剂中毒等挑战严重制约了该技术的发展。在本文中,我们报道了一种由 Ni、Fe、Cr 和 Mo 元素组成的二维纳米片季金属氢氧化物催化剂。通过原位电化学活化,部分钼元素在催化剂中被浸出并发生形态转变。获得了更高的金属价态和许多 O 空位,在工业要求的 500 mA cm –2 电流密度下,在整体碱性海水电解中提供了优异的催化活性和耐腐蚀性在室温下 1.82 V 低电压下超过 1000 小时。漂浮的太阳能海水分解装置显示出 20.61 ± 0.77% 的太阳能制氢 (STH) 效率。这项工作展示了高效太阳能海水电解装置的发展,并可能促进清洁能源转换的研究。
IF:15.800Q1 ACS nano, 2023-Mar-14. DOI: 10.1021/acsnano.2c10477 PMID: 36808966
Abstract:
Photovoltaic hydrogen production from seawater is of great significance. Challenges of solar-driven seawater electrolysis, for example, competing among chlorine evolution reactions, chloride corrosion, and catalyst poisoning, seriously restrict the development … >>>
Photovoltaic hydrogen production from seawater is of great significance. Challenges of solar-driven seawater electrolysis, for example, competing among chlorine evolution reactions, chloride corrosion, and catalyst poisoning, seriously restrict the development of this technology. In this paper, we report a two-dimensional nanosheet quaternary metal hydroxide catalyst composed of Ni, Fe, Cr, and Mo elements. By in situ electrochemical activation, a partial Mo element was leached and morphologically transformed in the catalyst. The higher metal valence states and many O vacancies were obtained, providing excellent catalytic activity and corrosion resistance in overall alkaline seawater electrolysis operating at an industrial-required current density of 500 mA cm over 1000 h under 1.82 V low voltages at room temperature. The floating solar seawater splitting device shows a 20.61 ± 0.77% efficiency of solar energy to hydrogen (STH). This work demonstrates the development of efficient solar seawater electrolysis devices and potentially promotes research on clean energy conversion. <<<
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510.
符毓 Yu (2023-02-28 21:08):
#paper https://doi.org/10.1103/PhysRevApplied.6.021001 Physical Review Applied, 2016, Nonvolatile Memory Based on Nonlinear Magnetoelectric Effects。在过去的十年中,已经提出和探索了多种多铁性或磁电存储器的概念。此文提出了一种基于多铁性磁电系数 (α) 的多种状态来实现多级非易失性存储器的新原理。 这种多级磁电存储器保留了铁电随机存取存储器的所有优点,并克服了极化破坏性读取的缺点。
Abstract:
The magnetoelectric effects in multiferroics have a great potential in creating next-generation memory devices. We use an alternative concept of nonvolatile memory based, on a type of nonlinear magnetoelectric effects … >>>
The magnetoelectric effects in multiferroics have a great potential in creating next-generation memory devices. We use an alternative concept of nonvolatile memory based, on a type of nonlinear magnetoelectric effects showing a butterfly-shaped hysteresis loop. The principle is to utilize the states of the magnetoelectric coefficient, instead of magnetization, electric polarization, or resistance, to store binary information. Our experiments in a device made of the PMN-PT/Terfenol- D multiferroic heterostructure clearly demonstrate that the sign of the magnetoelectric coefficient can be repeatedly switched between positive and negative by applying electric fields, confirming the feasibility of this principle. This kind of nonvolatile memory has outstanding practical virtues such as simple structure, easy operation in writing and reading, low power, fast speed, and diverse materials available. <<<
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511.
庞庞 (2023-02-28 21:02):
#paper doi:https://doi.org/10.1038/nn.4164 Parcellating cortical functional networks in individuals 大脑网络的位置、大小等属性具有个体差异。之前的研究忽略了这些差异,运用组水平的分区模板计算功能连接矩阵,导致功能连接个体间差异的混淆。本研究是第一个提出个体化功能网络的研究,基于组水平网络分区模板迭代的思路,获得了具有可重复性、可以捕捉个体间差异、可通过电刺激验证的功能网络个体化分区,为我们进行个体化功能网络的研究提供了新思路。
IF:21.200Q1 Nature neuroscience, 2015-Dec. DOI: 10.1038/nn.4164 PMID: 26551545
Abstract:
The capacity to identify the unique functional architecture of an individual's brain is a crucial step toward personalized medicine and understanding the neural basis of variation in human cognition and … >>>
The capacity to identify the unique functional architecture of an individual's brain is a crucial step toward personalized medicine and understanding the neural basis of variation in human cognition and behavior. Here we developed a cortical parcellation approach to accurately map functional organization at the individual level using resting-state functional magnetic resonance imaging (fMRI). A population-based functional atlas and a map of inter-individual variability were employed to guide the iterative search for functional networks in individual subjects. Functional networks mapped by this approach were highly reproducible within subjects and effectively captured the variability across subjects, including individual differences in brain lateralization. The algorithm performed well across different subject populations and data types, including task fMRI data. The approach was then validated by invasive cortical stimulation mapping in surgical patients, suggesting potential for use in clinical applications. <<<
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512.
小W (2023-02-28 20:31):
#paper doi:https://doi.org/10.1016/j.cell.2022.12.027 Loss of epigenetic information as a cause of mammalian aging 本文主要论述细胞对DNA断裂(DSB)修复过程中染色质修饰剂的重新定位(RCM)的变化,侵蚀了表观遗传图谱,这种表观遗传信息的丢失加速了细胞衰老和老化。本文使用I-PpoI内切酶建立 DSB 的细胞和小鼠(ICE)老化模型,通过比较十个月后肝脏、皮肤、脑、肌肉、活力等方面在代谢、基因组、表观遗传和组蛋白水平的衰老标志物,ICE 小鼠较对照小鼠 表现更高的老化速度。提出以下观点:1.哺乳动物的衰老与DSB修复效率相关,但与其他类型的修复无关,可能是因为只有对细胞生存的严重威胁才足以破坏表观基因组,从而导致衰老。2.RCM反应会发育破坏基因、DNA甲基转移酶(DNMTs)的表达模式,并释放被沉默的逆转录转座子。3.通过OSK(Yamanaka因子Oct4、Sox2、Klf4)处理,衰老细胞的衰老标记物的水平恢复到与阴性对照相似的水平,(哺乳动物衰老细胞可能保留了恢复年轻的表观遗传信息)。4.表观遗传信息的丢失是衰老的原因。
IF:45.500Q1 Cell, 2023-01-19. DOI: 10.1016/j.cell.2022.12.027 PMID: 36638792
Abstract:
All living things experience an increase in entropy, manifested as a loss of genetic and epigenetic information. In yeast, epigenetic information is lost over time due to the relocalization of … >>>
All living things experience an increase in entropy, manifested as a loss of genetic and epigenetic information. In yeast, epigenetic information is lost over time due to the relocalization of chromatin-modifying proteins to DNA breaks, causing cells to lose their identity, a hallmark of yeast aging. Using a system called "ICE" (inducible changes to the epigenome), we find that the act of faithful DNA repair advances aging at physiological, cognitive, and molecular levels, including erosion of the epigenetic landscape, cellular exdifferentiation, senescence, and advancement of the DNA methylation clock, which can be reversed by OSK-mediated rejuvenation. These data are consistent with the information theory of aging, which states that a loss of epigenetic information is a reversible cause of aging. <<<
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513.
哪有情可长 (2023-02-28 20:25):
#paper Atlas of exercise metabolism reveals timedependent signatures of metabolic homeostasis,Cell Metabolism,15 January 2022, doi.org/10.1016/j.cmet.2021.12.016. 组织对运动的敏感性和反应会因为运动时间和生物钟的调整而不同,目前什么时间运动能够引发理想代谢结果还没有完全确定。作者为了解决组织如何独立和协调的对定时运动做出反应,利用7种小鼠组织和血清在一天不同的时间点进行急性运动后鉴定起代谢物的反应。通过对不同组织之间代谢物的动力学比较分析,揭示了一天中特定时间运动的局部和全身代谢物的无差异。通过构建运动代谢图谱,发现了跟跟时间依赖性运动代谢产物2-HB的产生和分布的清晰和生理背景,说明了运动对代谢的健康有促进作用。另外该作者在2018年,cell上也发表了一篇生物钟相关的文章:Atlas of Circadian Metabolism Reveals System-wide Coordination and Communication between Clocks。作者同时对8个小鼠组织进行了24小时代谢组学分析。在系统能量平衡和慢性营养应激(高脂饮食[HFD])的背景下,展示了昼夜节律代谢的时空图谱。
IF:27.700Q1 Cell metabolism, 2022-02-01. DOI: 10.1016/j.cmet.2021.12.016 PMID: 35030324
Abstract:
Tissue sensitivity and response to exercise vary according to the time of day and alignment of circadian clocks, but the optimal exercise time to elicit a desired metabolic outcome is … >>>
Tissue sensitivity and response to exercise vary according to the time of day and alignment of circadian clocks, but the optimal exercise time to elicit a desired metabolic outcome is not fully defined. To understand how tissues independently and collectively respond to timed exercise, we applied a systems biology approach. We mapped and compared global metabolite responses of seven different mouse tissues and serum after an acute exercise bout performed at different times of the day. Comparative analyses of intra- and inter-tissue metabolite dynamics, including temporal profiling and blood sampling across liver and hindlimb muscles, uncovered an unbiased view of local and systemic metabolic responses to exercise unique to time of day. This comprehensive atlas of exercise metabolism provides clarity and physiological context regarding the production and distribution of canonical and novel time-dependent exerkine metabolites, such as 2-hydroxybutyrate (2-HB), and reveals insight into the health-promoting benefits of exercise on metabolism. <<<
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514.
Vincent (2023-02-28 19:08):
#paper DOI: https://doi.org/10.1038/s41592-021-01205-4 DOME: recommendations for supervised machine learning validation in biology. Nat Methods 2021. 机器学习方法在生物学领域变得越发重要,理想情况下机器学习预测结果最好能够被生物实验所验证,但是目前绝大多数的文章并没有配套的实验验证步骤,而只是通过计算指标来反映模型的性能,但这类计算指标往往受很多步骤的影响(例如数据集选择,训练集测试集的拆分,正负样本平衡性等等),导致最后的结论不一定稳定可靠。这篇评论文章旨在号召相关领域应该建立一套机器学习研究的写作和汇报标准,从而提高该领域内机器学习应用的交流效率。这篇文章从数据,算法,模型,评价四个方面列举了诸多影响模型性能的因素,并建议研究者在发表机器学习的文章时应该参照这四个方面的问题,详细阐述方法的细节,以此推动文章评审的效率,提高研究的透明度和可重复性
515.
周周复始 (2023-02-28 17:22):
#paper DOI: 10.1007/978-3-030-87735-4_21 CAS-Net: Conditional Atlas Generation and Brain Segmentation for Fetal MRI. 为了解决图像伪影和噪声以及训练标签不精确的问题,提出了一种新的架构,在一个端到端的pipeline中同时学习分割和生成条件图谱,同时基于微分同胚配准来保证图谱生成的平滑性和连续性 。该图谱使模型能够在不依赖于输入图像的强度值的情况下学习解剖先验,并提高分割性能,特别是在图像质量差没有金标准训练标签的情况下。用该方法在dHCP的253个被试上进行了训练和评估,结果表明,可以生成具有明显边界的特定年龄条件图谱。
Abstract:
Fetal Magnetic Resonance Imaging (MRI) is used in prenatal diagnosis and to assess early brain development. Accurate segmentation of the different brain tissues is a vital step in several brain … >>>
Fetal Magnetic Resonance Imaging (MRI) is used in prenatal diagnosis and to assess early brain development. Accurate segmentation of the different brain tissues is a vital step in several brain analysis tasks, such as cortical surface reconstruction and tissue thickness measurements. Fetal MRI scans, however, are prone to motion artifacts that can affect the correctness of both manual and automatic segmentation techniques. In this paper, we propose a novel network structure that can simultaneously generate conditional atlases and predict brain tissue segmentation, called CAS-Net. The conditional atlases provide anatomical priors that can constrain the segmentation connectivity, despite the heterogeneity of intensity values caused by motion or partial volume effects. The proposed method is trained and evaluated on 253 subjects from the developing Human Connectome Project (dHCP). The results demonstrate that the proposed method can generate conditional age-specific atlas with sharp boundary and shape variance. It also segment multi-category brain tissues for fetal MRI with a high overall Dice similarity coefficient (DSC) of 85.2% for the selected 9 tissue labels. <<<
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516.
小年 (2023-02-28 16:39):
#paper doi: 10.1172/JCI46043. Circadian rhythms, sleep, and metabolism. J Clin Invest. 2011 Jun;121(6):2133-41. 昼夜节律遗传基础的发现扩展了我们对行为和生理学的时间组织的认识。大脑和身体之间的新陈代谢是以每日“昼夜节律”的方式调节的,然而,系统地扰乱活动的昼夜节律模式,会导致正常代谢模式的破坏,包括肥胖、糖尿病和心血管疾病,与代谢功能障碍,文中评估了molecular timing如何为理解和开发肥胖和糖尿病的治疗方法创造新的机会。未来的研究将继续侧重于扩大我们对大脑和外周时钟如何在细胞自主和非自主水平上协调调节代谢过程的理解,营养通量如何将有关环境的信息转化为时钟,以及昼夜节律对人类健康和疾病的影响。
Abstract:
The discovery of the genetic basis for circadian rhythms has expanded our knowledge of the temporal organization of behavior and physiology. The observations that the circadian gene network is present … >>>
The discovery of the genetic basis for circadian rhythms has expanded our knowledge of the temporal organization of behavior and physiology. The observations that the circadian gene network is present in most living organisms from eubacteria to humans, that most cells and tissues express autonomous clocks, and that disruption of clock genes results in metabolic dysregulation have revealed interactions between metabolism and circadian rhythms at neural, molecular, and cellular levels. A major challenge remains in understanding the interplay between brain and peripheral clocks and in determining how these interactions promote energy homeostasis across the sleep-wake cycle. In this Review, we evaluate how investigation of molecular timing may create new opportunities to understand and develop therapies for obesity and diabetes. <<<
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517.
张浩彬 (2023-02-28 15:49):
#paper 10.5555/2503308.2188396 Noise-Contrastive Estimation of Unnormalized Statistical Models, with Applications to Natural Image Statistics啃一下nce。nce主要是解决一个问题,当分类类别太多的失衡,softmax的归一化因子计算量太大,于是作者提出nce作为一个替代。作者很巧妙地设计了一个代理任务,把原有的分类问题,转化为一个吧目标从噪声样本中识别出来的二分类问题,从而规避了计算规范化因子的计算量问题。并且作者证明了,当样本趋向于无穷的时候,nce等价于mle。
Abstract:
We consider the task of estimating, from observed data, a probabilistic model that is parameterized by a finite number of parameters. In particular, we are considering the situation where the … >>>
We consider the task of estimating, from observed data, a probabilistic model that is parameterized by a finite number of parameters. In particular, we are considering the situation where the model probability density function is unnormalized. That is, the model is only specified up to the partition function. The partition function normalizes a model so that it integrates to one for any choice of the parameters. However, it is often impossible to obtain it in closed form. Gibbs distributions, Markov and multi-layer networks are examples of models where analytical normalization is often impossible. Maximum likelihood estimation can then not be used without resorting to numerical approximations which are often computationally expensive. We propose here a new objective function for the estimation of both normalized and unnormalized models. The basic idea is to perform nonlinear logistic regression to discriminate between the observed data and some artificially generated noise. With this approach, the normalizing partition function can be estimated like any other parameter. We prove that the new estimation method leads to a consistent (convergent) estimator of the parameters. For large noise sample sizes, the new estimator is furthermore shown to behave like the maximum likelihood estimator. In the estimation of unnormalized models, there is a trade-off between statistical and computational performance. We show that the new method strikes a competitive trade-off in comparison to other estimation methods for unnormalized models. As an application to real data, we estimate novel two-layer models of natural image statistics with spline nonlinearities. <<<
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518.
半面阳光 (2023-02-28 14:45):
#paper https://doi.org/10.1016/j.gim.2022.11.004 Genetics in Medicine, 2023, Noninvasive prenatal screening (NIPS) for fetal chromosome abnormalities in a general-risk population: An evidence-based clinical guideline of the American College of Medical Genetics and Genomics (ACMG). ACMG在2022年12月发表了最新版的NIPT应用指南。这个版本的指南是对2016版指南的更新。这次更新过程中,ACMG的NIPS专项小组采用系统性综述和GRADE“证据到决策”框架等分析评估方法,对NIPS用于一般风险人群的各项参数进行了评估,形成了6条主要应用性建议。相较于传统的筛查方法,NIPS在21、18和13三体的筛查性检测中,无论单胎妊娠还是双胎妊娠,都展现了其优越性。ACMG给出明确意见,建议一般风险人群采用NIPS进行21、18和13三体的筛查,以替代传统筛查手段。同时明确指出,建议使用NIPS来筛查胎儿性染色体非整倍体异常。除了这几条给出“强烈建议”的意见之外,指南还对NIPS用于小片段缺失以及其他类型CNVs的检测给出了指导性建议。
Abstract:
PURPOSE: This workgroup aimed to develop an evidence-based clinical practice guideline for the use of noninvasive prenatal screening (NIPS) for pregnant individuals at general risk for fetal trisomy 21, trisomy … >>>
PURPOSE: This workgroup aimed to develop an evidence-based clinical practice guideline for the use of noninvasive prenatal screening (NIPS) for pregnant individuals at general risk for fetal trisomy 21, trisomy 18, or trisomy 13 and to evaluate the utility of NIPS for other chromosomal disorders.METHODS: The NIPS Evidence-Based Guideline Work Group (n = 7) relied on the results from the recent American College of Medical Genetics and Genomics (ACMG) systematic review to form the evidentiary basis of this guideline. Workgroup members used the Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision framework to draft recommendations. The guideline underwent extensive internal and external peer review with a public comment period before approval by the ACMG Board of Directors.RESULTS: Evidence consistently demonstrated improved accuracy of NIPS compared with traditional screening methods for trisomies 21, 18, and 13 in singleton and twin gestations. Identification of rare autosomal trisomies and other microdeletion syndromes with NIPS is an emerging area of interest.CONCLUSION: ACMG strongly recommends NIPS over traditional screening methods for all pregnant patients with singleton and twin gestations for fetal trisomies 21, 18, and 13 and strongly recommends NIPS be offered to patients to screen for fetal sex chromosome aneuploidy. <<<
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519.
姗姗来迟 (2023-02-27 21:25):
#paper https://openaccess.thecvf.com/content_CVPR_2019/html/Tang_Learning_to_Compose_Dynamic_Tree_Structures_for_Visual_Contexts_CVPR_2019_paper.html title:为视觉上下文组成动态树结构的学习 提出,将图像中的objects放置到视觉上下文中,组成动态树结构,帮助场景图生成和视觉问答等视觉推理任务。该可视化上下文树模型,称为VCTREE,有两个关键优势: 1)高效且富有表现力的二叉树编码了对象之间固有的并行/层次关系; 2)动态结构从图像到图像,从任务到任务,允许更多内容/任务特定的消息传递。
Abstract:
We propose to compose dynamic tree structures that place the objects in an image into a visual context, helping visual reasoning tasks such as scene graph generation and visual Q&A. … >>>
We propose to compose dynamic tree structures that place the objects in an image into a visual context, helping visual reasoning tasks such as scene graph generation and visual Q&A. Our visual context tree model, dubbed VCTree, has two key advantages over existing structured object representations including chains and fully-connected graphs: 1) The efficient and expressive binary tree encodes the inherent parallel/hierarchical relationships among objects, e.g., "clothes" and "pants" are usually co-occur and belong to "person"; 2) the dynamic structure varies from image to image and task to task, allowing more content-/task-specific message passing among objects. To construct a VCTree, we design a score function that calculates the task-dependent validity between each object pair, and the tree is the binary version of the maximum spanning tree from the score matrix. Then, visual contexts are encoded by bidirectional TreeLSTM and decoded by task-specific models. We develop a hybrid learning procedure which integrates end-task supervised learning and the tree structure reinforcement learning, where the former's evaluation result serves as a self-critic for the latter's structure exploration. Experimental results on two benchmarks, which require reasoning over contexts: Visual Genome for scene graph generation and VQA2.0 for visual Q&A, show that VCTree outperforms state-of-the-art results while discovering interpretable visual context structures. <<<
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520.
Spring (2023-02-27 21:24):
#paper Metabolically (un)healthy obesity and risk of obesity-related cancers: a pooled study 合并研究:新陈代谢(非)健康的肥胖和与肥胖有关的癌症风险 10.1093/jnci/djad008 基于超79万名欧洲人BMI和代谢评分(通过血压、血糖和甘油三酯定义),评估代谢处于异常或正常的人群与癌症风险间的关联; 相比代谢健康体重正常者,代谢异常的肥胖人群患肥胖相关癌症、结直肠癌、胆囊癌等风险增加,子宫内膜癌、肝癌和肾细胞癌的风险最高; 代谢健康的肥胖人群患肥胖相关癌症、男性结肠癌、子宫内膜癌和胆囊癌等风险增加,尽管风险关系较弱; BMI和代谢健康状况叠加会增加肥胖相关癌症、直肠癌及子宫内膜癌等风险。
Abstract:
BACKGROUND: Studies of obesity with or without metabolic aberrations, commonly termed metabolically unhealthy or healthy obesity, in relation to cancer risk are scarce.METHODS: We investigated body mass index (normal weight, … >>>
BACKGROUND: Studies of obesity with or without metabolic aberrations, commonly termed metabolically unhealthy or healthy obesity, in relation to cancer risk are scarce.METHODS: We investigated body mass index (normal weight, overweight, obesity) jointly and in interaction with metabolic health status in relation to obesity-related cancer risk (n = 23 630) among 797 193 European individuals. A metabolic score comprising mid-blood pressure, plasma glucose, and triglycerides was used to define metabolically healthy and unhealthy status. Hazard ratios (HRs) and multiplicative interactions were assessed using Cox regression, and additive interactions were assessed using the relative excess risk for interaction. All statistical tests were 2-sided.RESULTS: Metabolically unhealthy obesity, with a baseline prevalence of 7%, was, compared with metabolically healthy normal weight, associated with an increased relative risk of any obesity-related cancer and of colon, rectal, pancreas, endometrial, liver, gallbladder, and renal cell cancer (P < .05), with the highest risk estimates for endometrial, liver, and renal cell cancer (HR = 2.55-3.00). Metabolically healthy obesity showed a higher relative risk for any obesity-related cancer and colon (in men), endometrial, renal cell, liver, and gallbladder cancer, though the risk relationships were weaker. There were no multiplicative interactions, but there were additive, positive interactions between body mass index and metabolic health status on obesity-related and rectal cancer among men and on endometrial cancer (P < .05).CONCLUSIONS: This study highlights that the type of metabolic obesity phenotype is important when assessing obesity-related cancer risk. In general, metabolic aberrations further increased the obesity-induced cancer risk, suggesting that obesity and metabolic aberrations are useful targets for prevention. <<<
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