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1.
颜林林 (2024-11-15 23:02):
#paper doi:10.1101/2024.01.18.24301478, medRxiv, Connecting genomic results for psychiatric disorders to human brain cell types and regions reveals convergence with functional connectivity. 这是今年1月在medRxiv发出的文章(至今尚未正式发表),来自瑞典卡罗林斯卡学院。关于精神疾病的研究,核磁主要探讨表型或功能相关脑区的定位,基因组学通过大规模人群基因检测和GWAS定位基因和突变,但两者之间尚未能直接联系。现有的人脑单细胞测序数据主要来自健康受试者,虽然能够将脑区与分子机制联系起来,但缺乏疾病相关数据。本研究通过一系列方法(如TDEP和S-LDSC),将GWAS数据与人类单核转录组数据关联,将精神疾病等表型与特定脑区及特定细胞类型联系起来。此外,研究使用fMRI数据对关键脑区(如海马体、杏仁核和前额皮层)的功能连接特性进行了验证,结果支持遗传学和转录组学发现的脑区定位。这一整合方法为理解精神疾病的多基因机制及其大脑定位提供了新的可能性。
Abstract:
AbstractUnderstanding the temporal and spatial brain locations etiological for psychiatric disorders is essential for targeted neurobiological research. Integration of genomic insights from genome-wide association studies with single-cell transcriptomics is a … >>>
AbstractUnderstanding the temporal and spatial brain locations etiological for psychiatric disorders is essential for targeted neurobiological research. Integration of genomic insights from genome-wide association studies with single-cell transcriptomics is a powerful approach although past efforts have necessarily relied on mouse atlases. Leveraging a comprehensive atlas of the adult human brain, we prioritized cell types via the enrichment of SNP-heritabilities for brain diseases, disorders, and traits, progressing from individual cell types to brain regions. Our findings highlight specific neuronal clusters significantly enriched for the SNP-heritabilities for schizophrenia, bipolar disorder, and major depressive disorder along with intelligence, education, and neuroticism. Extrapolation of cell-type results to brain regions reveals important patterns for schizophrenia with distinct subregions in the hippocampus and amygdala exhibiting the highest significance. Cerebral cortical regions display similar enrichments despite the known prefrontal dysfunction in those with schizophrenia highlighting the importance of subcortical connectivity. Using functional MRI connectivity from cases with schizophrenia and neurotypical controls, we identified brain networks that distinguished cases from controls that also confirmed involvement of the central and lateral amygdala, hippocampal body, and prefrontal cortex. Our findings underscore the value of single-cell transcriptomics in decoding the polygenicity of psychiatric disorders and offer a promising convergence of genomic, transcriptomic, and brain imaging modalities toward common biological targets. <<<
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<jats:title>摘要</jats:title><jats:p>了解精神疾病病因的大脑时间和空间位置对于有针对性的神经生物学研究至关重要。将来自全基因组关联研究的基因组见解与单细胞转录组学相结合是一种强大的方法,尽管过去的工作必然依赖于小鼠图谱。利用成人大脑的综合图谱,我们通过富集脑部疾病、障碍和性状的 SNP 遗传性来确定细胞类型的优先级,从单个细胞类型发展到大脑区域。我们的研究结果强调了特定神经元簇显着富集精神分裂症、双相情感障碍和重度抑郁症的 SNP 遗传性以及智力、教育和神经质。将细胞类型结果外推到大脑区域揭示了精神分裂症的重要模式,其中海马体和杏仁核中不同的亚区域表现出最高意义。尽管精神分裂症患者存在已知的前额叶功能障碍,但大脑皮层区域表现出类似的丰富,这突出了皮层下连接的重要性。使用来自精神分裂症病例和神经典型对照的功能性 MRI 连接,我们确定了将病例与对照组区分开来的大脑网络,这些病例也证实了中央和外侧杏仁核、海马体和前额叶皮层的参与。我们的研究结果强调了单细胞转录组学在解码精神疾病多基因性方面的价值,并为基因组、转录组和脑成像模式向共同的生物学靶标提供了有希望的融合。</jats:p>
2.
龙海晨 (2024-11-07 13:24):
#paper Galea GL, Paradise CR, Meakin LB, Camilleri ET, Taipaleenmaki H, Stein GS, Lanyon LE, Price JS, van Wijnen AJ, Dudakovic A. Mechanical strain-mediated reduction in RANKL expression is associated with RUNX2 and BRD2. Gene. 2020 Dec;763S:100027. doi: 10.1016/j.gene.2020.100027. Epub 2020 Jan 16. PMID: 34493364.这是一篇研究机械应变与成骨活动的文章。机械负荷相关的应变触发成骨细胞形成骨,同时抑制破骨细胞的骨吸收,从而开启骨形成和骨吸收的过程。骨细胞可能通过分泌硬化素(SOST)(抑制成骨细胞)和表达核因子-κB配体受体激活剂。(RANKL/TNFSF11)来生成破骨细胞协调这一过程。机械应变会降低 SOST 和 RANKL 表达。RUNX2 敲低会增加 SOST 水平。 RUNX2 促进机械应变介导的 RANKL 抑制。BRD2 表达受机械应变和 RUNX2 调节。
3.
DeDe宝 (2024-11-02 15:29):
#paper:doi: doi/10.1126/sciadv.ado4103 Noninvasive modulation of the hippocampal-entorhinal complex during spatial navigation in humans.本研究利用经颅时间干扰电刺激(tTIS)技术,非侵入性地调节人脑海马-内嗅皮层复合体(HC-EC)活动,以研究其在空间导航中的作用。通过在虚拟现实空间导航任务中应用连续(cTBS)和间歇(iTBS)theta-burst刺激模式,与控制条件相比较,研究发现iTBS提高了空间导航性能,与海马活动增加和内嗅皮层网格细胞样活动减少相关。这些结果表明,通过非侵入性手段可以直接调节HC-EC活动,改变空间导航行为,为认知障碍患者提供了潜在的治疗策略。
Abstract:
Because of the depth of the hippocampal-entorhinal complex (HC-EC) in the brain, understanding of its role in spatial navigation via neuromodulation was limited in humans. Here, we aimed to better … >>>
Because of the depth of the hippocampal-entorhinal complex (HC-EC) in the brain, understanding of its role in spatial navigation via neuromodulation was limited in humans. Here, we aimed to better elucidate this relationship in healthy volunteers, using transcranial temporal interference electric stimulation (tTIS), a noninvasive technique allowing to selectively neuromodulate deep brain structures. We applied tTIS to the right HC-EC in either continuous or intermittent theta-burst stimulation patterns (cTBS or iTBS), compared to a control condition, during a virtual reality–based spatial navigation task and concomitant functional magnetic resonance imaging. iTBS improved spatial navigation performance, correlated with hippocampal activity modulation, and decreased grid cell–like activity in EC. Collectively, these data provide the evidence that human HC-EC activity can be directly and noninvasively modulated leading to changes of spatial navigation behavior. These findings suggest promising perspectives for patients suffering from cognitive impairment such as following traumatic brain injury or dementia. <<<
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4.
muton (2024-10-31 23:48):
#paper:doi: https://doi.org/10.1101/2022.08.29.505742 Parallel cognitive maps for short-term statistical and long-term semantic relationships in the hippocampal formation 海马-内嗅皮层不仅加工空间信息,同时也加工其它类型的信息,如关系信息(社交信息)等。但是海马到底是把刺激的不同维度整合到一个联合地图中还是每个信息纬度都是一个平行地图?作者重新分析了之前Garvert等的核磁数据,实验任务可以构建出一个包含语义信息和统计规律的地图,作者通过计算模型,mds等方法计算证明了海马中是形成了多个地图的,并不是将多个结构整合到一个地图中。
Abstract:
AbstractThe hippocampal-entorhinal system uses cognitive maps to represent spatial knowledge and other types of relational information, such as the transition probabilities between objects. However, objects can often be characterized in … >>>
AbstractThe hippocampal-entorhinal system uses cognitive maps to represent spatial knowledge and other types of relational information, such as the transition probabilities between objects. However, objects can often be characterized in terms of different types of relations simultaneously, e.g. semantic similarities learned over the course of a lifetime as well as transitions experienced over a brief timeframe in an experimental setting. Here we ask how the hippocampal formation handles the embedding of stimuli in multiple relational structures that differ vastly in terms of their mode and timescale of acquisition: Does it integrate the different stimulus dimensions into one conjunctive map, or is each dimension represented in a parallel map? To this end, we reanalyzed functional magnetic resonance imaging (fMRI) data from Garvert et al. (2017) that had previously revealed an entorhinal map which coded for newly learnt statistical regularities. We used a triplet odd-one-out task to construct a semantic distance matrix for presented items and applied fMRI adaptation analysis to show that the degree of similarity of representations in bilateral hippocampus decreases as a function of semantic distance between presented objects. Importantly, while both maps localize to the hippocampal formation, this semantic map is anatomically distinct from the originally described entorhinal map. This finding supports the idea that the hippocampal-entorhinal system forms parallel cognitive maps reflecting the embedding of objects in diverse relational structures. <<<
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5.
白鸟 (2024-10-31 23:04):
#paper DOI: 10.1038/nmeth.3364,MiXCR: software for comprehensive adaptive immunity profiling. 2015年,milaboratory推出了MiXCR软件,MiXCR是二代测序TCR/BCR免疫组库分析软件,能有效处理双端和单端测序,考虑序列质量,纠正PCR错误并识别种系超突变。 (1)MiXCR比对:将测序读数与T细胞或B细胞受体的V、D、J 和 C基因进行比对; (2)MiXCR组装:利用上一步获得的比对结果组装成克隆型(以提取特定基因区域,如 CDR3); (3)结果导出和绘图:将比对结果或克隆型结果导出和绘图; MiXCR软件分学术版本和商业版本,软件封装得很好,几乎为所有商业/通用试剂盒开发了定制预配置的分析流程,单命令即可完成操作。
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半面阳光 (2024-10-31 17:55):
#paper DOI: 10.1097/GRF.0000000000000804, Clin Obstet Gynecol, 2023, Unique Challenges of NIPT for Sex Chromosome Aneuploidy. 这是一篇综述文章。作者主要围绕NIPT检测性染色体异常时存在的三个难点进行了总结梳理。一是性染色体异常的表型类型较多,二是性染色体异常存在较多的嵌合情况,三是NIPT检测性染色体异常的阳性预测值(PPV)比较低,尤其是跟其他常染色体比较而言。除了这三个检测中的难点之外,作者还探讨了在检测前以及检出性染色体高风险之后,如何进行遗传咨询等内容。性染色体异常的检测是NIPT检测在临床应用中的一个重要方面,同时也是问题较多、情况比较复杂的一个领域。这篇文章的主题很具实际应用性。
Abstract:
Noninvasive prenatal testing (NIPT) for the sex chromosome aneuploidies (45,X, 47,XXY, 47,XXX, and 47,XYY) differs significantly from that for the autosomal aneuploidies (trisomy 13, 18, and 21). As a group, … >>>
Noninvasive prenatal testing (NIPT) for the sex chromosome aneuploidies (45,X, 47,XXY, 47,XXX, and 47,XYY) differs significantly from that for the autosomal aneuploidies (trisomy 13, 18, and 21). As a group, sex chromosome aneuploidies occur more commonly (1/400) than any one isolated autosomal aneuploidy, the phenotypic variation is greater, the role of mosaicism more challenging, and the positive predictive value of a high-risk NIPT result is substantially lower. These considerations should be identified during pretest counseling, the inclusion of sex chromosome testing offered separately, and the differences from autosomal aneuploidy NIPT clearly delineated. <<<
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7.
庞庞 (2024-10-31 17:06):
#paper https://doi.org/10.1038/s44220-024-00309-y A mega-analysis of functional connectivity and network abnormalities in youth depression 这篇文章思路很简单,就是整合了青少年抑郁症的功能影像数据,然后和正常人进行了比较,确定了异常的功能连接,相关的功能网络。然后发现这些功能连接多分布在hub节点,同时与临床症状有关系。值得学习的是这篇文章的写作,非常流畅,而且详略得当。
8.
前进 (2024-10-31 15:09):
#paper arXiv:2408.05839v2 Deep Learning in Medical Image Registration: Magic or Mirage? 38th Conference on Neural Information Processing Systems (NeurIPS 2024) 这篇论文深入探讨了医学图像配准领域中,基于深度学习的图像配准(DLIR)与传统优化方法的性能对比。论文比较了传统优化方法和基于学习的学习方法在DIR中的性能,指出传统方法在跨模态的泛化能力和稳健性能方面具有优势,而基于学习的方法则通过弱监督来实现更优的性能。通过一系列实验,论文验证了在无监督设置下,基于学习的方法在标签匹配性能上并没有显著超越传统方法,并提出了一个假设,即学习方法中的架构设计不太可能影响像素强度分布和标签之间的互信息,因此也不太可能显著提升基于学习的方法的性能。此外,论文还展示了在弱监督下,基于学习的方法具有更高的配准精度,这是传统方法难以实现的。然而,基于学习的方法对数据分布的变化较为敏感,并且未能展现出对数据分布变化的鲁棒性。论文最后给出结论,如果没有大型标记数据集,传统优化方法仍然是更优的选择。
arXiv, 2024-08-11T18:20:08Z. DOI: 10.48550/arXiv.2408.05839
Abstract:
Classical optimization and learning-based methods are the two reigningparadigms in deformable image registration. While optimization-based methodsboast generalizability across modalities and robust performance, learning-basedmethods promise peak performance, incorporating weak supervision and … >>>
Classical optimization and learning-based methods are the two reigningparadigms in deformable image registration. While optimization-based methodsboast generalizability across modalities and robust performance, learning-basedmethods promise peak performance, incorporating weak supervision and amortizedoptimization. However, the exact conditions for either paradigm to perform wellover the other are shrouded and not explicitly outlined in the existingliterature. In this paper, we make an explicit correspondence between themutual information of the distribution of per-pixel intensity and labels, andthe performance of classical registration methods. This strong correlationhints to the fact that architectural designs in learning-based methods isunlikely to affect this correlation, and therefore, the performance oflearning-based methods. This hypothesis is thoroughly validated withstate-of-the-art classical and learning-based methods. However, learning-basedmethods with weak supervision can perform high-fidelity intensity and labelregistration, which is not possible with classical methods. Next, we show thatthis high-fidelity feature learning does not translate to invariance to domainshift, and learning-based methods are sensitive to such changes in the datadistribution. Finally, we propose a general recipe to choose the best paradigmfor a given registration problem, based on these observations. <<<
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9.
尹志 (2024-10-31 13:55):
#paper doi.org/10.1038/sdata.2014.22 Quantum chemistry structures and properties of 134 kilo molecules, Scientific Data 1, 140022, 2014. 这是著名的数据集QM9的原始论文,最近在做相关计算工作, 又好好读了一下。非常重要的工作,给后续各种量化计算提供了特别方便的benchmark。该工作使用DFT方法(B3LYP/6-31G(2df,p))计算了134k种小分子的各种量化性质,比如能量、偶极矩、极化率等。
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盼盼 (2024-10-31 10:55):
#paper doi.org/10.1038/s41586-024-08133-1 2024年10月30日,深圳先进技术研究院胡政团队在Nature发表题为Polyclonal-to-monoclonal transition in colorectal precancerous evolution的研究论文,首次揭示了肿瘤从多克隆到单克隆转变的早期演化新模式,系统阐明了这一过程中细胞间的相互作用机制。通过谱系示踪技术和单细胞转录组测序,研究团队在小鼠模型和人类癌前病变组织中观察到,早期肿瘤病变往往具有多个独立的细胞克隆来源,这些克隆在肿瘤发生的早期阶段通过细胞间的通讯和合作共同推动病变进展。随着肿瘤的发展,这些多克隆逐渐被一个优势克隆所替代,转变为单克隆肿瘤。这说明单克隆肿瘤比多克隆肿瘤具有更高的恶性程度,单克隆肿瘤可能代表肿瘤发生的更“晚期”阶段。这些发现为理解肿瘤起源提供了全新的概念框架,并提出通过靶向细胞间通讯来实现早期干预的肿瘤预防新策略。
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符毓 Yu (2024-10-30 21:44):
#paper doi:10.3390/aerospace6030026 Aerospace, 2019, Electric VTOL Configurations Comparison 本文介绍了自五十年代以来建造的 VTOL,并讨论了它们的优点、缺点和问题。对三种代表性 eVTOL(每种主要配置一种)的五个主要参数和三个参考任务进行了比较。这些参数包括磁盘负载、总悬停时间、巡航速度、实际航程和飞行时间。通过计算所需的时间和能量,评估了 eVTOL 在城市、城郊和远程任务中的性能。结果表明,最佳配置取决于任务。多旋翼飞机在悬停时效率更高。矢量推力喷气发动机在巡航时效率更高,航程也更大。升力 + 巡航是一种折衷方案。
Abstract:
In the last ten years, different concepts of electric vertical take-off and landing aircrafts (eVTOLs) have been tested. This article addresses the problem of the choice of the best configuration. … >>>
In the last ten years, different concepts of electric vertical take-off and landing aircrafts (eVTOLs) have been tested. This article addresses the problem of the choice of the best configuration. VTOLs built since the fifties are presented and their advantages, disadvantages, and problems are discussed. Three representative eVTOLs, one for each main configuration, are compared on five main parameters and three reference missions. The parameters are disk loading, total hover time, cruise speed, practical range, and flight time. The performance of the eVTOLs on the urban, extra-urban, and long-range mission is evaluated computing the time and energy required. The results show that the best configuration depends on the mission. The multirotor is more efficient in hover. The vectored thrust jet is more efficient in cruise and has a higher range. The lift + cruise is a compromise. <<<
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12.
徐炳祥 (2024-10-30 20:29):
#paper doi: 10.1016/j.molcel.2017.04.010 Molecular Cell, 2017, Dynamic Rewiring of Promoter-Anchored Chromatin Loops during Adipocyte Differentiation。这篇旧文是目前已知的唯一一项以3T3-L1细胞的体外脂肪分化过程为研究对象的三维基因组学研究。作者使用Promoter capture Hi-C (PCHi-C)技术测定了分化过程中的关键时点的染色质构象图谱,结合对应时点的RNA-seq,重要转录因子和组蛋白修饰信号进行了联合分析。结果显示TAD结构在分化全称保持稳定,Promoter-enhancer相互作用(EPI)表现出明显的与分化过程中的基因表达调控模式一致的成波次状的增强和消退。这些行为与H3K27ac的富集和消退高度一致,而与H3K4me1/2无关。此外,在与Promoter相连的Enhancer上同时富集激活信号如MED1/SMC1/P300,和抑制信号如NcoR/HDAC,反映出EPI对基因表达的复杂调控作用。本文提供了一套比较全面的3T3-L1分化过程的表观组学数据,其分析和可视化方法均有可借鉴之处,尤其是对三个时点的序贯数据的分析和呈现。
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哪有情可长 (2024-10-30 19:59):
#paper Genetic control of branching patterns in grass inflorescences 2022,The Plant Cell doi.org/10.1093/plcell/koac080, 文章对禾本科植物的产量主要受花序组织控制,其中花序发育是禾本科植物的研究重点。这篇综述聚焦于花序分生组织向小穗过渡的生长时期,详细阐述了禾本科植物花序结构的生长特征,论述了一些禾本科作物花序发育的保守模块,如腋分生组织、次级和高级分支结构的形成,此外还分析了生长激素及多个基因构成的调控网络在营养生长和小穗发育中的功能,其中具体的发育进程因自然和人为选择的不同而存在显著差异。
Abstract:
Abstract Inflorescence branching in the grasses controls the number of florets and hence the number of seeds. Recent data on the underlying genetics come primarily from rice and maize, although … >>>
Abstract Inflorescence branching in the grasses controls the number of florets and hence the number of seeds. Recent data on the underlying genetics come primarily from rice and maize, although new data are accumulating in other systems as well. This review focuses on a window in developmental time from the production of primary branches by the inflorescence meristem through to the production of glumes, which indicate the transition to producing a spikelet. Several major developmental regulatory modules appear to be conserved among most or all grasses. Placement and development of primary branches are controlled by conserved auxin regulatory genes. Subtending bracts are repressed by a network including TASSELSHEATH4, and axillary branch meristems are regulated largely by signaling centers that are adjacent to but not within the meristems themselves. Gradients of SQUAMOSA-PROMOTER BINDING-like and APETALA2-like proteins and their microRNA regulators extend along the inflorescence axis and the branches, governing the transition from production of branches to production of spikelets. The relative speed of this transition determines the extent of secondary and higher order branching. This inflorescence regulatory network is modified within individual species, particularly as regards formation of secondary branches. Differences between species are caused both by modifications of gene expression and regulators and by presence or absence of critical genes. The unified networks described here may provide tools for investigating orphan crops and grasses other than the well-studied maize and rice. <<<
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14.
张浩彬 (2024-10-30 10:19):
#paper AdapterFusion: Non-Destructive Task Composition for Transfer Learning https://doi.org/10.48550/arXiv.2005.00247 adapter的改进版本,AdapterFusion。简单来说就是多个任务分别构建adapter,之后通过组合adapters的方式实现更好知识融合。 摘要简述:序列微调和多任务学习是旨在融合多个任务知识的方法;然而,它们存在灾难性遗忘和数据集平衡困难的问题。为了解决这些缺点,我们提出了AdapterFusion,这是一种新的两阶段学习算法,可以利用多个任务的知识。首先,在知识提取阶段,我们学习称为adapters的特定任务参数,这些参数封装了特定任务的信息。然后,我们在单独的知识组合步骤中组合adapters。我们表明,通过分离这两个阶段,即知识提取和知识组合,分类器可以以非破坏性的方式有效地利用从多个任务中学习的表示。我们在16个不同的NLU任务上对AdapterFusion进行了实证评估,发现它可以有效地在模型的不同层结合各种类型的知识。我们表明,我们的方法优于传统策略,如完全微调以及多任务学习。我们的代码和adapters可在AdapterHub.ml上获得。
arXiv, 2020-05-01T07:03:42Z. DOI: 10.48550/arXiv.2005.00247
Abstract:
Sequential fine-tuning and multi-task learning are methods aiming toincorporate knowledge from multiple tasks; however, they suffer fromcatastrophic forgetting and difficulties in dataset balancing. To address theseshortcomings, we propose AdapterFusion, a … >>>
Sequential fine-tuning and multi-task learning are methods aiming toincorporate knowledge from multiple tasks; however, they suffer fromcatastrophic forgetting and difficulties in dataset balancing. To address theseshortcomings, we propose AdapterFusion, a new two stage learning algorithm thatleverages knowledge from multiple tasks. First, in the knowledge extractionstage we learn task specific parameters called adapters, that encapsulate thetask-specific information. We then combine the adapters in a separate knowledgecomposition step. We show that by separating the two stages, i.e., knowledgeextraction and knowledge composition, the classifier can effectively exploitthe representations learned from multiple tasks in a non-destructive manner. Weempirically evaluate AdapterFusion on 16 diverse NLU tasks, and find that iteffectively combines various types of knowledge at different layers of themodel. We show that our approach outperforms traditional strategies such asfull fine-tuning as well as multi-task learning. Our code and adapters areavailable at AdapterHub.ml. <<<
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15.
钟鸣 (2024-10-29 17:26):
doi:10.1007/s12264-019-00379-4 Long-term Fiber Photometry for Neuroscience Studies 摘录要点如下: DIY光纤植入物(插针),因此用功率计检测光透过性,连接插针前的功率为30uw,连接后不应低于25uw。 AAV 可在高达 4 °C 的温度下储存至少 1 个月,滴度不会明显下降 注射病毒时,抽取比实际注射的病毒载体量多 100 nL 使用手术刀刀片使颅骨粗糙;这将有助于陶瓷套圈与牙科粘接剂牢固地粘附到颅骨上 颅骨打孔时颅钻不要钻穿硬脑膜,从孔中取出骨碎屑,并使用注射器尖端 (0.4 mm) 刺穿硬脑膜,而不会损坏皮层。 固定螺钉距离光纤至少至少 2 mm 以 46 nL/min 的速率注射病毒载体,总体积为 200 nL–500 nL(注射速度不应快于 100 nL/min) 不要让牙科粘结剂与皮肤接触;这将导致植入纤维的固定不成功 将哑光黑色指甲油均匀涂抹在干燥的牙科上,以阻挡光纤光度测量过程中自然光的干扰 将盐酸林可霉素和盐酸利多卡因凝胶涂抹在消毒的切口部位,作为镇痛和抗炎药 使用于光纤光度测量记录的房间尽可能暗 开机后等待~15分钟,使光强度稳定下来 新更换的光跳线应在高光强度(例如 10 mW)下漂白至少 20 分钟 将跳线尖端的实际激光功率调整为 30 μW。避免使用更高的功率,因为它会导致荧光信号的强烈漂白 连接动物后的最初几分钟内,由于荧光漂白,荧光信号振幅会迅速降低。信号将相对稳定在仍高于初始基线的水平(即未连接的动物)。 我们选择基线的 5 个标准差作为阈值,以定义荧光信号的显着波动。
16.
小年 (2024-10-28 16:48):
#paper Mosquito taste responses to human and floral cues guide biting and feeding Nature, 2024, doi:10.1038/s41586-024-08047-y 最近一篇关于蚊子的研究,研究人员首先提取了 46 种不同的味觉化合物,包括糖、盐、苦味化合物和氨基酸等,并观察蚊子味觉器官中的神经元对它们的反应。他们发现一些化合物(如糖类)会使许多神经元兴奋,而有些化合物则抑制了神经元的活动,这表明蚊子具有很强的味觉编码能力(比果蝇厉害),能区分各种各样的味觉。作者还研究了不同味道的化合物对蚊子行为的影响,发现不同味道会促进或抑制不同行为。例如,某些苦味化合物会减少蚊子的进食行为,但对蚊子产卵却无影响;盐和一些通常存在于人体汗液中的氨基酸在单独呈现时对蚊子叮咬行为无影响,但结合在一起时会促进蚊子叮咬。(盐+氨基酸=吸引蚊子) 此外,当研究人员向蚊子提供人类汗液样本时,发现蚊子对某些样本表现出强烈的叮咬偏好,他们认为这可能是有些人比其他人更容易被蚊子叮咬的部分原因。(但是没有发现到底是什么东西导致的) 总得来说文章说名了蚊子又很强的味觉系统,且对不同的味觉有偏好性,也部分说明了什么样的化合物能吸引蚊子,但是最吸引蚊子叮咬的是什么还没研究明白。 最近登革热闹得厉害,大家注意防蚊。
17.
李翛然 (2024-10-28 13:54):
#paper Modeling protein-small molecule conformational ensembles with ChemNet doi:10.1101/2024.09.25.614868 baker 又一力作,直接把我们最近正在想的共形几何问题引入蛋白质结构与小分子互作,已经直接实现出来了, 下一步其实就是把这个和Diffusion结合,那么小分子de-novo设计就可以完全自动化了。 baker帮我完成了50%的工作~~~
Abstract:
AbstractModeling the conformational heterogeneity of protein-small molecule systems is an outstanding challenge. We reasoned that while residue level descriptions of biomolecules are efficient for de novo structure prediction, for probing … >>>
AbstractModeling the conformational heterogeneity of protein-small molecule systems is an outstanding challenge. We reasoned that while residue level descriptions of biomolecules are efficient for de novo structure prediction, for probing heterogeneity of interactions with small molecules in the folded state an entirely atomic level description could have advantages in speed and generality. We developed a graph neural network called ChemNet trained to recapitulate correct atomic positions from partially corrupted input structures from the Cambridge Structural Database and the Protein Data Bank; the nodes of the graph are the atoms in the system. ChemNet accurately generates structures of diverse organic small molecules given knowledge of their atom composition and bonding, and given a description of the larger protein context, and builds up structures of small molecules and protein side chains for protein-small molecule docking. Because ChemNet is rapid and stochastic, ensembles of predictions can be readily generated to map conformational heterogeneity. In enzyme design efforts described here and elsewhere, we find that using ChemNet to assess the accuracy and pre-organization of the designed active sites results in higher success rates and higher activities; we obtain a preorganized retroaldolase with akcat/KMof 11000 M-1min- 1, considerably higher than any pre-deep learning design for this reaction. We anticipate that ChemNet will be widely useful for rapidly generating conformational ensembles of small molecule and small molecule-protein systems, and for designing higher activity preorganized enzymes. <<<
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18.
颜林林 (2024-10-27 08:10):
#paper doi:10.1126/science.add7046, Science, 2023, Transcriptomic diversity of cell types across the adult human brain. 这篇文章来自瑞典卡罗琳斯卡学院(全球最顶尖的医学研究机构之一,负责颁发诺贝尔生理学或医学奖)和艾伦脑科学研究所(全球神经科学研究的重要中心之一,旨在通过大规模的脑科学研究和开放数据共享,推动对大脑结构和功能的理解)。该研究基于三位成人捐赠者的脑组织样本,采集了数百个不同脑区的样本,覆盖了包括端脑、中脑及脑干等部位,进行单核测序,得到超过三百万个细胞的表达数据,采用层次聚类和图分析技术对这些数据进行分析,将细胞划分为31个超簇及3000多个亚簇,并揭示了各簇在不同区域中的分布特点与功能关系,比较特别的是其中一个被命名为“溅射(Splatter)神经元”的超簇,因其复杂的分子特性和广泛分布,反映了神经元及其功能网络的高度异质性,成为本研究的重点之一。论文还阐明了皮层内兴奋性与抑制性神经元的层次性结构、不同脑区神经元的异质性、非神经元的星形胶质细胞的多样性和分布异质性等,从单细胞层面拓展了我们对基因表达与脑功能网络关系的理解。
Science, 2023-10-13. DOI: 10.1126/science.add7046
Abstract:
The human brain directs complex behaviors, ranging from fine motor skills to abstract intelligence, but the diversity of cell types that support these skills has not been fully described. In … >>>
The human brain directs complex behaviors, ranging from fine motor skills to abstract intelligence, but the diversity of cell types that support these skills has not been fully described. In this work, we used single-nucleus RNA sequencing to systematically survey cells across the entire adult human brain. We sampled more than three million nuclei from approximately 100 dissections across the forebrain, midbrain, and hindbrain in three postmortem donors. Our analysis identified 461 clusters and 3313 subclusters organized largely according to developmental origins and revealing high diversity in midbrain and hindbrain neurons. Astrocytes and oligodendrocyte-lineage cells also exhibited regional diversity at multiple scales. The transcriptomic census of the entire human brain presented in this work provides a resource for understanding the molecular diversity of the human brain in health and disease. <<<
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19.
林海onrush (2024-10-15 05:09):
#paper, Anyons in an exactly solved model and beyond, https://doi.org/10.1016/j.aop.2005.10.005, 任意子的经典之作、堪称诺奖分量,Alexei Kitaev撰写的经典论文《任意子在一个精确可解模型及其扩展中的表现》探讨了任意子(Anyons)的性质。任意子是一种只能在二维空间中出现的具有特殊统计特性的粒子。研究集中研究了一个基于蜂窝晶格的自旋1/2系统,其最近邻的自旋之间存在XX、YY或ZZ类型的相互作用。通过将该系统简化为一个静态Z2规范场中的自由费米子系统,作者精确地解决了这个模型。 描述了两个主要的物理相位: 阿贝尔任意子(Abelian Anyons):在其中一个具有能隙的相位中,系统中会出现阿贝尔任意子。这些任意子的交换仅会导致相位偏移,表现出简化的编织规则。阿贝尔任意子的激发是稳定的,并表现出分数统计,这是拓扑序的典型特征。 非阿贝尔任意子(Non-Abelian Anyons):在另一个相位中,尽管系统本身无能隙,但当引入磁场时,系统会形成能隙。在这个相位中,激发变为非阿贝尔任意子,其编织规则更加复杂,类似于Ising模型中的共形块。非阿贝尔任意子具有处理量子计算的潜力,因为其量子态可以通过编织操作来操控。 使用的关键数学工具包括: Majorana费米子:论文通过将自旋用Majorana费米子表示,解决了该模型。Majorana费米子是一种实费米子算符,能够将自旋系统转化为可解的二次费米子系统。 陈数(Chern number):论文引入了一个谱陈数ν来表征不同的相位,阿贝尔相位对应ν = 0,而非阿贝尔相位则对应ν = ±1。 同时探讨了边界模、热传导以及任意子的代数理论。Kitaev详细描述了这些准粒子的性质及其在拓扑量子计算中的潜在应用。拓扑有序态被证明可以作为一种稳健的量子记忆和计算平台,因为它们对局部扰动具有良好的保护作用。任意子在拓扑量子计算中的应用潜力巨大,其中量子信息编码在非阿贝尔任意子的量子态中,通过编织这些粒子来实现量子门操作。这种“纯拓扑”方案提供了一种稳健的量子计算方法。
20.
刘昊辰 (2024-10-12 10:09):
#paper arXiv:2409.12272v1 [cs.LG] 18 Sep 2024, Mastering Chess with a Transformer Model. 这是一篇关于Transformer模型在国际象棋中的应用的研究论文。论文证明了Transformer在国际象棋中的有效性在很大程度上取决于注意力机制中位置编码的选择。基于这一观察,论文采用了Shaw等人的通用位置编码方案,并大规模地训练了具有这种技术和其他增强功能的模型,将得到的架构称为ChessFormer。这种架构在对弈实力和解谜能力方面显著优于先前的工作,且计算成本只是其一小部分。下载地址:https://arxiv.org/pdf/2409.12272
arXiv, 2024-09-18T19:05:21Z. DOI: 10.48550/arXiv.2409.12272
Abstract:
Transformer models have demonstrated impressive capabilities when trained atscale, excelling at difficult cognitive tasks requiring complex reasoning andrational decision-making. In this paper, we explore the application oftransformer models to chess, … >>>
Transformer models have demonstrated impressive capabilities when trained atscale, excelling at difficult cognitive tasks requiring complex reasoning andrational decision-making. In this paper, we explore the application oftransformer models to chess, focusing on the critical role of the positionencoding within the attention mechanism. We show that in chess, transformersendowed with a sufficiently versatile position encoding can match existingchess-playing models at a fraction of the computational cost. Our architecturesignificantly outperforms AlphaZero at 8x fewer FLOPS and matches priorgrandmaster-level transformer-based agents at 30x fewer FLOPS. <<<
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