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The great catastrophe: causes of the Permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： Paul B.Wignall David P.G.Bond school of Earth & Environment University of Leeds school of Environmental sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high temperatures.Other kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

BCCLR:A Skeleton-Based Action Recognition with Graph Convolutional Network Combining Behavior Dependence and Context Clues

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Computers, Materials & Continua 2024年第3期78卷 4489-4507页

作者： Yunhe Wang Yuxin Xia Shuai Liu College of Information Science and Engineering Institute of Interdisciplinary StudiesHunan Normal UniversityChangsha410081China school of educational sciences Institute of Interdisciplinary StudiesHunan Normal UniversityChangsha410081China

In recent years,skeleton-based action recognition has made great achievements in Computer Vision.A graph convolutional network(GCN)is effective for action recognition,modelling the human skeleton as a spatio-temporal graph.Most GCNs define the graph topology by physical relations of the human joints.However,this predefined graph ignores the spatial relationship between non-adjacent joint pairs in special actions and the behavior dependence between joint pairs,resulting in a low recognition rate for specific actions with implicit correlation between joint pairs.In addition,existing methods ignore the trend correlation between adjacent frames within an action and context clues,leading to erroneous action recognition with similar poses.Therefore,this study proposes a learnable GCN based on behavior dependence,which considers implicit joint correlation by constructing a dynamic learnable graph with extraction of specific behavior dependence of joint pairs.By using the weight relationship between the joint pairs,an adaptive model is constructed.It also designs a self-attention module to obtain their inter-frame topological relationship for exploring the context of actions.Combining the shared topology and the multi-head self-attention map,the module obtains the context-based clue topology to update the dynamic graph convolution,achieving accurate recognition of different actions with similar poses.Detailed experiments on public datasets demonstrate that the proposed method achieves better results and realizes higher quality representation of actions under various evaluation protocols compared to state-of-the-art methods.

关键词： Action recognition deep learning GCN behavior dependence context clue self-attention

Reducing Subspaces of Toeplitz Operators Induced by a Class of Non-analytic Monomials over the Unit Ball

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1767-1777页

作者： Yan Yue SHI Bo ZHANG Xu TANG Yu Feng LU school of Mathematical sciences Ocean University of China school of Mathematics and Information sciences Yantai University school of Mathematical sciences Space Engineering University school of Mathematical sciences Dalian University of Technology

In this paper, we describe the minimal reducing subspaces of Toeplitz operators induced by non-analytic monomials on the weighted Bergman spaces and Dirichlet spaces over the unit ball B2. It is proved that each minimal reducing subspace M is finite dimensional, and if dim M ≥ 3,then M is induced by a monomial. Furthermore, the structure of commutant algebra ■ is determined by N and the two dimensional minimal reducing subspaces of ■. We also give some interesting examples.

关键词： Reducing subspace operator-weighted shifts Toeplitz operator von Neumann algebra 47B35 47B37

Multifunction-oriented high-mobility polymer semiconductors

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National Science Review 2024年第3期11卷 16-19页

作者： Mingliang Zhu Yunlong Guo Yunqi Liu Beijing National Laboratory for Molecular sciences Organic Solids Laboratory Institute of Chemistry Chinese Academy of Sciences school of Chemical sciences University of Chinese Academy of Sciences

The discovery of conductive polyacetylene has initiated interdisciplinary research into condensed matter physics and synthetic chemistry in organic electronics. Unlike their inorganic and small-molecule counterparts, polymer semiconductors possess the inherent advantages of facile solution processing,large-area manufacturing, excellent mechanical strength and intrinsic flexibility.

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Physiological and pathological functions of circular RNAs in the nervous system

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Neural Regeneration Research 2024年第2期19卷 342-349页

作者： Min Zhou Shi Li Chuan Huang school of Life sciences Chongqing UniversityChongqingChina

Circular RNAs(circRNAs)are a class of covalently closed single-stranded RNAs that are expressed during the development of specific cells and tissues.CircRNAs play crucial roles in physiological and pathological processes by sponging microRNAs,modulating gene transcription,controlling the activity of certain RNA-binding proteins,and producing functional peptides.A key focus of research at present is the functionality of circRNAs in the nervous system and several advances have emerged over the last 2 years.However,the precise role of circRNAs in the nervous system has yet to be comprehensively reviewed.In this review,we first summarize the recently described roles of circRNAs in brain development,maturity,and aging.Then,we focus on the involvement of circRNAs in various diseases of the central nervous system,such as brain cancer,chronic neurodegenerative diseases,acute injuries of the nervous system,and neuropathic pain.A better understanding of the functionality of circRNAs will help us to develop potential diagnostic,prognostic,and therapeutic strategies to treat diseases of the nervous system.

关键词： Alzheimer’s disease amyotrophic lateral sclerosis brain development circRNAs neuropathic pain Parkinson’s disease

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Rational Solutions of First Order Algebraic Ordinary Differential Equations

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Journal of Systems Science & Complexity 2024年第2期37卷 567-580页

作者： FENG Shuang SHEN Liyong school of Physical and Mathematical sciences Nanjing Tech UniversityNanjing 211816China school of Mathematical sciences University of Chinese Academy of SciencesBeijing 100049China

Let f(t,y,y')=∑ _(i=0)^(n )a_(i)(t,y)y'^(i)=0 be an irreducible first order ordinary differential equation with polynomial coefficients.Eremenko in 1998 proved that there exists a constant C such that every rational solution of f(t,y,y')=0 is of degree not greater than C.Examples show that this degree bound C depends not only on the degrees of f in t,y,y' but also on the coefficients of f viewed as the polynomial in t,y,y'.In this paper,the authors show that if f satisfies deg(f,y)0,then the degree bound C only depends on the degrees of f in t,y,y',and furthermore we present an explicit expression for C in terms of the degrees of f in t,y,y'.

关键词： Degree bound first order AODE height rational solution

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Immune checkpoint inhibitors:breakthroughs in cancer treatment

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Cancer Biology & Medicine 2024年第6期21卷 451-472页

作者： Xueqing Kong Jinyi Zhang Shuwei Chen Xianyang Wang Qing Xi Han Shen Rongxin Zhang Laboratory of Immunology and Inflammation School of Life Sciences and Biopharmaceutics Guangdong Pharmaceutical University Department of Biology School of Life Sciences and Biopharmaceutics Guangdong Pharmaceutical University

Over the past two decades, immunotherapies have increasingly been considered as first-line treatments for most cancers. One such treatment is immune checkpoint blockade(ICB), which has demonstrated promising results against various solid tumors in clinical trials. Monoclonal antibodies(mAbs) are currently available as immune checkpoint inhibitors(ICIs). These ICIs target specific immune checkpoints, including cytotoxic T-lymphocyte-associated antigen-4(CTLA-4) and programmed cell death protein 1(PD-1). Clinical trial results strongly support the feasibility of this immunotherapeutic approach. However, a substantial proportion of patients with cancer develop resistance or tolerance to treatment, owing to tumor immune evasion mechanisms that counteract the host immune response.Consequently, substantial research focus has been aimed at identifying additional ICIs or synergistic inhibitory receptors to enhance the effectiveness of anti-PD-1, anti-programmed cell death ligand 1(anti-PD-L1), and anti-CTLA-4 treatments. Recently, several immune checkpoint molecular targets have been identified, such as T cell immunoreceptor with Ig and ITIM domains(TIGIT), mucin domain containing-3(TIM-3), lymphocyte activation gene-3(LAG-3), V-domain immunoglobulin suppressor of T cell activation(VISTA), B and T lymphocyte attenuator(BTLA), and signal-regulatory protein α(SIRPα). Functional m Abs targeting these molecules are under development. CTLA-4, PD-1/PD-L1, and other recently discovered immune checkpoint proteins with distinct structures are at the forefront of research. This review discusses these structures, as well as clinical progress in m Abs targeting these immune checkpoint molecules and their potential applications.

关键词： CTLA-4 ICIs Immunotherapy PD-1 cancer

Impact of tourism on the vigilance behavior of the Cyprus rock agama(Laudakia cypriaca)

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Integrative Zoology 2024年第3期19卷 577-583页

作者： Artur GOLAWSKI Iris CHARALAMBIDOU Sylwia GOLAWSKA Faculty of sciences Siedlce University of Natural Sciences and HumanitiesSiedlcePolandand Department of Life sciences School of Life and Health SciencesUniversity of NicosiaNicosiaCyprus

Escape behavior is a common antipredator strategy among wild animals.Here,we investigated the effect of four factors on the vigilance behavior of the endemic Cyprus rock agama(Laudakia cypriaca).Flight initiation distance(FID,the minimum distance to which an observer can approach a lizard before it flees)was measured in relation to the type of location(tourist vs.nontourist area),the observer’s starting distance,air temperature,and substrate temperature.We collected data for 39 agamas in tourist areas and 34 of these lizards in nontourist areas.As a whole,the mean starting distance was 10.5 m and the FID was 3.6 m.The average substrate temperature was 34.0℃ and the average air temperature 29.6℃.Only the type of area affected the agamas’escape decisions with FID being 1.8 m shorter in tourist areas than in nontourist areas(2.7 m vs.4.5 m).This is probably due to the habituation of lizards to the presence of humans in the former areas.This study shows that tourism strongly affects the behavior of lizards,which may have consequences for the functioning of the population.Tourists can increase the safety of lizards by creating a human shield to deter predators.Once the tourist season is over,lizards may become more vulnerable to predators.

关键词： anthropogenic disturbance flight initiation distance lizards tourism vigilance behavior

Amyloid-beta and tau protein beyond Alzheimer's disease

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Neural Regeneration Research 2024年第6期19卷 1262-1276页

作者： Morteza Abyadeh Vivek Gupta Joao A.Paulo Arezoo Gohari Mahmoudabad Sina Shadfar Shahab Mirshahvaladi Veer Gupta Christine T.O.Nguyen David I.Finkelstein Yuyi You Paul A.Haynes Ghasem H.Salekdeh Stuart L.Graham Mehdi Mirzaei ProGene Technologies Pty Ltd. 2. Department of Clinical Medicine Faculty of Medicine Health and Human Sciences Macquarie Medical School Macquarie University Department of Cell Biology Harvard Medical School school of Medicine Deakin University Department of Optometry and Vision sciences School of Health Sciences Faculty of Medicine Dentistry and Health Sciences University of Melbourne The Florey Institute of Neuroscience and Mental Health The University of Melbourne school of Natural sciences Macquarie University

The aggregation of amyloid-beta peptide and tau protein dysregulation are implicated to play key roles in Alzheimer’s disease pathogenesis and are considered the main pathological hallmarks of this devastating disease. Physiologically, these two proteins are produced and expressed within the normal human body. However, under pathological conditions, abnormal expression, posttranslational modifications, conformational changes, and truncation can make these proteins prone to aggregation, triggering specific disease-related cascades. Recent studies have indicated associations between aberrant behavior of amyloid-beta and tau proteins and various neurological diseases, such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis, as well as retinal neurodegenerative diseases like Glaucoma and age-related macular degeneration. Additionally, these proteins have been linked to cardiovascular disease, cancer, traumatic brain injury, and diabetes, which are all leading causes of morbidity and mortality. In this comprehensive review, we provide an overview of the connections between amyloid-beta and tau proteins and a spectrum of disorders.

关键词： amyloid-beta cancer cardiovascular diseases diabetes neurodegeneration Tau traumatic brain injury