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Deformation correlations,stress field switches and evolution of an orogenic intersection:The Pan-African Kaoko-Damara orogenic junction,Namibia

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Geoscience Frontiers 2017年第6期8卷 1187-1232页

作者： Ben Goscombe david a.foster david Gray Ben Wade Antonios Marsellos Jason Titus Integrated Terrane Analysis Research(ITAR) 18 Cambridge RdAldgate5154SAAustralia Department of Geological Sciences University of FloridaGainesvilleFL32611USA School of Earth Sciences University of TasmaniaHobartTASAustralia Adelaide Microscopy University of AdelaideAdelaide5005SAAustralia Hofstra University HempsteadNYUSA

Age calibrated deformation histories established by detailed mapping and dating of key magmatic time markers are correlated across all tectono-metamorphic provinces in the Damara Orogenic System.Correlations across structural belts result in an internally consistent deformation framework with evidence of stress field rotations with similar timing,and switches between different deformation events.Horizontal principle compressive stress rotated clockwise ~180°in total during Kaoko Belt evolution,and^135° during Damara Belt evolution.At most stages,stress field variation is progressive and can be attributed to events within the Damara Orogenic System,caused by changes in relative trajectories of the interacting Rio De La Plata,Congo,and Kalahari Cratons.Kaokoan orogenesis occurred earliest and evolved from collision and obduction at ~590 Ma,involving E-W directed shortening,progressing through different transpressional states with ~45° rotation of the stress field to strike-slip shear under NW-SE shortening at ~550-530 Ma.Damaran orogenesis evolved from collision at ~555-550 Ma with NW-SE directed shortening in common with the Kaoko Belt,and subsequently evolved through ~90°rotation of the stress field to NE-SW shortening at ~512-508 Ma.Both Kaoko and Damara orogenic fronts were operating at the same time,with all three cratons being coaxially convergent during the 550-530 Ma period;Rio De La Plata directed SE against the Congo Craton margin,and both together over-riding the Kalahari Craton margin also towards the SE.Progressive stress field rotation was punctuated by rapid and significant switches at ~530-525 Ma,~508 Ma and ~505 Ma.These three events included:(1)Culmination of main phase orogenesis in the Damara Belt,coinciding with maximum burial and peak metamorphism at 530-525 Ma.This occurred at the same time as termination of transpression and initiation of transtensional reactivation of shear zones in the Kaoko Belt.Principle compressive stress switched from NW-SE to NNW-SSE shortening in both Kaoko and Damar

关键词： Damara Orogen Stress fields Orogeny Assembly of Gondwana Event geochronology Deformation correlations

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TGF-β信号缺陷是否是人类癌症中的致命弱点?

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癌症 2008年第8期27卷 882-884页

作者： david a.foster Noga Gadir Department of Biological Sciences Hunter College of the City University of New YorkNew YorkUSA Department of Biological Sciences Hunter College of the City University of New YorkNew YorkNew YorkUSA Department of Molecular GeneticsWeizmann Institute of ScienceRehovot 76100Israel

癌细胞中的存活信号可激活mTOR-哺乳动物雷帕霉素靶蛋白。mTOR可抑制TGF-β信号,后者可使细胞周期停滞于G1后期,因此,活化后的mTOR可防止细胞周期停滞于TGF-β介导的检验点。雷帕霉素可重新激活TGF-β信号,从而导致G1期细胞停滞。在人... 详细信息

癌细胞中的存活信号可激活mTOR-哺乳动物雷帕霉素靶蛋白。mTOR可抑制TGF-β信号,后者可使细胞周期停滞于G1后期,因此,活化后的mTOR可防止细胞周期停滞于TGF-β介导的检验点。雷帕霉素可重新激活TGF-β信号,从而导致G1期细胞停滞。在人类癌症中,TGF-β信号通常发生缺陷,相反,在雷帕霉素作用下,TGF-β信号缺陷的癌细胞不发生G1期停滞,而发生凋亡。因此,在基于雷帕霉素的抗癌治疗策略中,TGF-β信号缺陷可能是癌细胞的致命弱点。

关键词： TGF-β mTOR 雷帕霉素凋亡存活信号癌细胞

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The magnetosheath at high spectral resolution

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Earth and Planetary Physics 2024年第1期8卷 234-246页

作者： K.D.Küntz D.Koutroumpa W.R.Dunn a.foster F.S.Porter D.G.Sibeck B.Walsh The Henry A.Rowland Department of Physics and Astronomy Johns Hopkins University3701 San Martin DriveBaltimoreMD21218USA NASA Goddard Space Flight Center 8800 Greenbelt RoadGreenbeltMD 20771USA LATMOS-OVSQ CNRSUVSQ Paris-SaclaySorbonne Université11 Boulevard d’Alembert78280GuyancourtFrance Department of Physics and Astronomy University College LondonLondonUK The Centre for Planetary Science at UCL/Birkbeck Gower StreetLondon WC1E 6BTUK Center for Astrophysics Harvard University&Smithsonian Institution60 Garden StreetCambridgeMA 02138USA Center for Space Physics Boston University110 Cummington MallBostonMAUSA

While we eagerly anticipate SMILE’s(Solar wind Magnetosphere Ionosphere Link Explorer)unprecedented X-ray observations of the Earth’s magnetosheath and the initiation of a new era of magnetospheric research,it seems appropriate to look ahead to the abilities of the next generation of astrophysics missions.Of these,the Line Emission Mapper(LEM),a large aperture micro-calorimeter based mission,is currently planned to be able to observe the magnetosheath at high spectral resolution(~2 eV).With a field of view of~30′,LEM will allow higher spatial resolution and higher cadence measurement of the motion of a very small portion of the magnetopause over relatively short periods of time(multiple hours),complementing SMILE’s global mapping.LEM’s strength is its spectral resolution.It will be able to measure the abundance of a broad range of elements and ionization states,many of which are inaccessible to current in situ instruments,and will be able to separate the emission from the magnetosheath from the emission from the cosmic X-ray background using the difference in their relative velocities.

关键词： magnetosheath charge exchange solar wind abundances

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Late Ordovician Mass Extinction: Earth, fire and ice

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National Science Review 2024年第1期11卷 51-65页

作者： david A.T.Harper Palaeoecosystems Group Department of Earth SciencesDurham University

The Late Ordovician Mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. Two phases have been identified near the start of the Hirnantian period and in the middle. It was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prompted a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. These symptoms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOME paleoecology palaeobiogeography biotas

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Analysis of ancient mass extinction recoveries in marine environments: generating strategies for managing outcomes of the current mass extinction

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National Science Review 2024年第1期11卷 8-10页

作者： david J.Bottjer Department of Earth Sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

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Risk factors for hepatocellular carcinoma associated with hepatitis C genotype 3 infection:A systematic review

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1596-1612页

作者： Hamzah Z Farooq Michael James Jane Abbott Patrick Oyibo Pip Divall Naheed Choudhry Graham R foster Blizard Institute Queen Mary University of LondonLondon E12ATUnited Kingdom School of Health and Psychological Sciences University of LondonLondon EC1V 0HBUnited Kingdom University Hospitals of Leicester Library University Hospitals of Leicester NHS TrustLeicester LE39QPUnited Kingdom

BACKGROUND Hepatitis C virus(HCV)is a blood-borne virus which globally affects around 79 million people and is associated with high morbidity and mortality.Chronic infection leads to cirrhosis in a large proportion of patients and often causes hepatocellular carcinoma(HCC)in people with cirrhosis.Of the 6 HCV genotypes(G1-G6),genotype-3 accounts for 17.9%of infections.HCV genotype-3 responds least well to directly-acting antivirals and patients with genotype-3 infection are at increased risk of HCC even if they do not have cirrhosis.AIM To systematically review and critically appraise all risk factors for HCC secondary to HCV-G3 in all settings.Consequently,we studied possible risk factors for HCC due to HCV-G3 in the literature from 1946 to 2023.METHODS This systematic review aimed to synthesise existing and published studies of risk factors for HCC secondary to HCV genotype-3 and evaluate their strengths and limitations.We searched Web of Science,Medline,EMBASE,and CENTRAL for publications reporting risk factors for HCC due to HCV genotype-3 in all settings,1946-2023.RESULTS Four thousand one hundred and forty-four records were identified from the four databases with 260 records removed as duplicates.Three thousand eight hundred and eighty-four records were screened with 3514 excluded.Three hundred and seventy-one full-texts were assessed for eligibility with seven studies included for analysis.Of the seven studies,three studies were retrospective case-control trials,two retrospective cohort studies,one a prospective cohort study and one a cross-sectional study design.All were based in hospital settings with four in Pakistan,two in South Korea and one in the United States.The total number of participants were 9621 of which 167 developed HCC(1.7%).All seven studies found cirrhosis to be a risk factor for HCC secondary to HCV genotype-3 followed by higher age(five-studies),with two studies each showing male sex,high alpha feto-protein,directly-acting antivirals treatment and achievement of sustained virologic res

关键词： Hepatocellular carcinoma Hepatitis C Genotype 3 Systematic review Blood-borne viruses Liver cancer

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Exercise immunology:Novel insights

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Journal of Sport and Health Science 2024年第3期13卷 277-279,I0001页

作者： david C.Nieman Human Performance Laboratory Appalachian State UniversityNorth Carolina Research CampusKannapolisNC 28081USA

The coronavirus disease 2019(COVID-19)pandemic heightened worldwide attention on the influence of exercise on the immune system.Questions were raised about whether regular moderate-to-vigorous physical activity(MVPA)could help prevent COVID-19 or mitigate symptoms when ill.Could MVPA bolster immunity among those most prone to COVID-19 including the elderly,obese,and immunocompromised patients?Does regular MVPA dampen systemic inflammation,thereby lessening the COVID-19 cytokine storm?

关键词： immunity inflammation thereby

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One-dimensional monotone nonautonomous dynamical systems

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Science China Mathematics 2024年第2期67卷 281-314页

作者： david Cheban Faculty of Mathematics and Computer Science Laboratory of Fundamental and Applied MathematicsMoldova State UniversityChisinau 2009Moldova

This work is devoted to the study of the dynamics of one-dimensional monotone nonautonomous(cocycle) dynamical systems. A description of the structures of their invariant sets, omega limit sets,Bohr/Levitan almost periodic and almost automorphic motions, global attractors, and pinched and minimalsets is given. An application of our general results is given to scalar differential and difference equations.

关键词： one-dimensional dynamics pinched and minimal sets global attractors monotone nonautonomous cocycle almost periodic solutions scalar differential/difference equations

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Kerogen Kinetic Distributions and Simulations Provide Insights into Petroleum Transformation Fraction (TF) Profiles of Organic-Rich Shales

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Journal of Earth Science 2024年第3期35卷 747-757页

作者： david A.Wood DWA Energy Limited Lincoln LN59JPUnited Kingdom

Two hundred and fifty single first-order Arrhenius reactions are simulated to generate S2 pyrograms at three heating rates 25,15,and 5°C·min-1.The activation energy(E)and pre-exponential factor(A)of the reactions simulated follow a long-established trend of those variable values displayed by shales and kerogens.The characteristics of the transformation fraction(TF)profiles(product generation window temperatures)of the simulated single reactions are compared to the TF profiles of recorded shale pyrograms generated by multiple reactions with different E-A values lying near the defined E-A trend.Important similarities and differences are observed between the TF profile values of the two datasets.The similarities support the spread of E-A values involved in shale pyrogram best fits.The differences are most likely explained by the complexity of the multiple kerogen first-order and second-order reactions contributing to the recorded shale pyrograms versus the simplicity and crispness of the single first-order reactions simulated.The results also justify the validity of using the previously described“variable E-A pyrogram-fitting method”of multi-heating-rate shale pyrograms enabling optimizers to choose multiple reactions from an unlimited range of E-A values.In contrast,further doubt is cast on the validity of the constant-A pyrogram-fitting method used by the Easy%Ro technique,in that a distribution of reactions with a single A value is unlikely to represent the complex variety of kerogen macerals observed in shale formations.TF profiles generated by the variable E-A pyrogram-fitting method lie close to the established E-A trend and are likely to provide more realistic TF generation window temperatures than TF profiles generated by the constant-A pyrogram-fitting method.

关键词： transformation fraction profiles simulated S2 pyrograms multiple heating rates kerogen/shale kinetics S2 pyrogram fitting techniques kerogen petroleum research.

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Role of climatic variability in shaping intraspecific variation of thermal tolerance in Mediterranean water beetles

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Insect Science 2024年第1期31卷 285-298页

作者： Susana Pallarés david Garoffolo Belén Rodríguez david Sánchez-Fernández Department of Zoology University of SevilleSevilleSpain Faculty of Biology Department of Ecology and HydrologyUniversity of MurciaCampus EspinardoMurciaSpain

The climatic variability hypothesis(CVH)predicts that organisms in more thermally variable environments have wider thermal breadths and higher thermal plasticity than those from more stable environments.However,due to evolutionary trade-offs,taxa with greater absolute thermal limits may have little plasticity of such limits(trade-off hypothesis).The CVH assumes that climatic variability is the ultimate driver of thermal tolerance variation across latitudinal and altitudinal gradients,but average temperature also varies along such gradients.We explored intraspecific variation of thermal tolerance in three typical Mediterranean saline water beetles(families Hydrophilidae and Dytiscidae).For each species,we compared two populations where the species coexist,with similar annual mean temperature but contrasting thermal variability(continental vs.coastal population).We estimated thermal limits of adults from each population,previously acclimated at 17,20,or 25℃.We found species-specific patterns but overall,our results agree with the CVH regarding thermal ranges,which were wider in the continental(more variable)population.In the two hydrophilid species,this came at the cost of losing plasticity of the upper thermal limit in this population,supporting the trade-off hypothesis,but not in the dytiscid one.Our results support the role of local adaptation to thermal variability and trade-offs between basal tolerance and physiological plasticity in shaping thermal tolerance in aquatic ectotherms,but also suggest that intraspecific variation of thermal tolerance does not fit a general pattern among aquatic insects.Overlooking such intraspecific variation could lead to inaccurate predictions of the vulnerability of aquatic insects to global warming.

关键词： acclimation capacity aquatic insects climate change heat coma temperature supercooling point thermal plasticity

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