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Ages, Trace Elements and Hf-Isotopic Compositions of Zircons from Claystones around the Permian-Triassic Boundary in the Zunyi Section, South China: Implications for Nature and Tectonic Setting of the Volcanism

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Journal of Earth Science 2015年第6期26卷 872-882页

作者： Qiuling Gao Zhong-Qiang Chen Ning Zhang William L.Griffin Wenchen Xia Guoqing Wang Tengfei Jiang Xuefei Xia Suzanne y.o'Reilly Exploration & Development Research Institute Zhongyuan Oilfield Company School of Earth Sciences China University of Geosciences Australian Research Council Centre of Excellence for Core to Crust Fluid Systems and GEMoC National Key Centre Department of Earth and Planetary Science Macquarie University State Key Laboratory.of Biogeology and Environmental Geology China University of Geosciences Shandong Lunan Institute of Geo-Engineering Exploration Jianghan oilfield Company

A growing body.of evidence shows that volcanism near the Permian-Triassic boundary（PTB） may be crucial in triggering the Permian–Triassic（P–Tr） mass extinction. Thus, the ash beds near the PTB in South China may carry information on this event. Three volcanic ash layers, altered to clay, outcropped in the PTB beds in Zunyi Section, Guizhou Province, Southwest China. The U-Pb ages, trace elements, and Hf-isotope compositions of zircon grains from these three ash beds were analyzed using LA-ICPMS and LA-MC-ICPMS. The zircons are mainly magmatic in origin（241-279 Ma） except for two inherited/xenocrystic zircons（939 and 2 325 Ma）. The ages of these magmatic zircons indicate three episodes of magmatism which occurred around the MiddleLate Permian boundary（-261.5 Ma, MLPB）, the Wuchiapingian-Changhsingian boundary（-254.5 Ma, WCB）, and the PTB（-250.5 Ma）, respectively. The first two episodes of magmatism near the MLPB and WCB may be attributed to magmatic inheritance or re-deposition. All magmatic zircons share similar trace-element and Hf-isotope compositions. They have y, Hf, Th and U contents and Nb/Ta ratios are typical of zircons from silicic calc-alkaline magmas. These zircons also exhibit enriched Hf-isotope compositions with _（εHf）（t） values of-11.4 to ＋0.2, which suggests that the three magmatic episodes involved melting of the continental crust. The more enriched Hf-isotope composition （_（εHf）（t）=-11.4--4.8） of Bed Zy13（-250.5 Ma） implies more input of ancient crustal material in the magma. Integration of the Hf-isotope and trace-element compositions of magmatic zircons suggest that these three episodes of magmatism may take place along the convergent continent margin in or near southwestern South China as a result of the closure of the Palaeo-Tethys ocean.

关键词： Permian-Triassic boundary zircon trace elements Hf isotope silicic volcanism,convergent continental margin South China.

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Cortical hem signaling center: functions, development, and potential implications for evolution and brain disorders

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Neural Regeneration Research 2025年第4期20卷 1079-1080页

作者： Victor V.Chizhikov Igor y.Iskusnykh Department of Anatomy and Neurobiology University of Tennessee Health Science CenterMemphisTNUSA

Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical *** such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in *** cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)*** cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).

关键词： epithelium Figure center

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Exercise preconditioning alleviates ischemia-induced memory deficits by increasing circulating adiponectin

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Neural Regeneration Research 2025年第5期20卷 1445-1454页

作者： Meifeng Zheng Borui Zhang Sonata S y yau Kwok-Fai So Li Zhang Haining ou Department of Rehabilitation Medicine Guangzhou Medical UniversityGuangzhouGuangdong ProvinceChina Department of Rehabilitation Medicine The Fifth Clinical College of Guangzhou Medical UniversityGuangzhouGuangdong ProvinceChina Key Laboratory.of CNS Regeneration(Ministry.of Education) Guangdong-Hong Kong-Macao Institute of CNS RegenerationJinan UniversityGuangzhouGuangdong ProvinceChina Department of Rehabilitation Sciences The Hong Kong Polytechnic UniversityHong Kong Special Administrative RegionChina State Key Laboratory.of Brain and Cognitive Science Li Ka Shing Faculty of MedicineThe University of Hong KongHong Kong Special Administrative RegionChina Center for Exercise and Brain Science School of PsychologyShanghai University of SportShanghaiChina Neuroscience and Neurorehabilitation Institute University of Health and Rehabilitation SciencesQingdaoShandong ProvinceChina

Cerebral ischemia is a major health risk that requires preventive approaches in addition to drug *** exercise enhances neurogenesis and synaptogenesis,and has been widely used for functional rehabilitation after *** this study,we determined whether exercise training before disease onset can alleviate the severity.of cerebral *** also examined the role of exercise-induced circulating factors in these *** mice were subjected to 14 days of treadmill exercise training before surgery for middle cerebral artery *** found that this exercise pre-conditioning strategy effectively attenuated brain infarct area,inhibited gliogenesis,protected synaptic proteins,and improved novel object and spatial memory *** analysis showed that circulating adiponectin plays a critical role in these preventive effects of *** activation of adiponectin receptors by Adipo Ron mimicked the effects of exercise,while inhibiting receptor activation abolished the exercise *** summary.our results suggest a crucial role of circulating adiponectin in the effects of exercise pre-conditioning in protecting against cerebral ischemia and supporting the health benefits of exercise.

关键词： adiponectin cerebral ischemia exercise pre-conditioning hippocampus memory function middle cerebral artery.occlusion prefrontal cortex synaptic proteins treadmill exercise

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Element diffusion ability in metasomatic agents and its effect on chemical characteristics of metasomatized peridotites

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Science China Earth Sciences 2006年第9期49卷 926-937页

作者： y S o’Reilly GEMoC ARC National Key Centre Department of Earth and Planetary Sciences Macquarie University Sydney N.S.W. 2109 Australia

Detailed in situ LM-ICPMS researches on the composite xenoliths from yingfengling volcano of Leizhou Peninsula, South China, indicate that most incompatible trace elements of clino- py.oxenes in composite xenoliths decrease spatially from py.oxenites to distal lherzolites, and com- patible elements and HREE increase steeply. The increasing and decreasing rate is distinct for dif- ferent trace elements, which give rise to element chromatographic fractionation within metasomatized lherzolites. The element chromatographic fractionation result actually from the difference in element diffusive rate in melts or fluids percolating through wall-rock lherzolites. Based on element variation profiles in composite xenoliths this study indicates that Sr, Nb, La and Ce have the highest diffusive mobility, MREE-HREE are moderate, and Zr, Hf, Ti, Ga and Sc are very low in most cases. Higher diffusive rates of LREE than HREE would enlarge the REE fractionation of metasomatized peridotites, and lower diffusive rate of Zr, Hf and Ti relative to neighbor REEs with similar incompatibility would cause the relative depletion of these elements in metasomatized peridotites. Trace elements com- monly have a higher diffusive rate in fluid-rich infiltrating melt, which will weaken element chroma- tographic fractionation during the metasomatism. The range of mantle metasomatism caused by sili- cate melt intrusion is very limited, generally within tens of centimeters wide. The width of metasoma- tized wall-rock peridotites near the py.oxenite or horblendite veins was strictly controlled by both melt volume and chemical characteristics.

关键词： composite xenolith, metasomatism, chromatographic fractionation, diffusive rate, Leizhou Peninsula.

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Gene therapy for spinal muscular atrophy:perspectives on the possibility.of optimizing SMN1 delivery to correct all neurological and systemic perturbations

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Neural Regeneration Research 2025年第7期20卷 2011-2012页

作者： Sharon J.Brown Rafael J.yáñez-Muñoz Heidi R.Fuller School of Pharmacy and Bioengineering Keele UniversityKeeleUK Wolfson Center for Inherited Neuromuscular Disease TORCH BuildingRJAH Orthopaedic HospitalOswestryUK *** Center of Gene and Cell TherapyDepartment of Biological SciencesSchool of Life Sciences and the EnvironmentRoyal Holloway University of LondonEghamUK

Spinal muscular atrophy(SMA)is a genetic condition that results in selective lower motor neuron loss with concomitant muscle weakness and *** genetic cause of SMA was understood in 1995 when loss or impairment of the survival motor neuron 1(SMN1)gene was identified as the main contributing factor(Lefebvre et al.,1995).This,in combination with the discovery that humans have a“back-up”gene,SMN2,which can produce low levels(approximately 10%)of the full-length functional SMN protein,has led to the generation of SMA-specific gene *** was traditionally classified according to age of symptom onset and developmental milestones achieved,with life expectancy and severity varying between ***,SMN2 copy number is used as a proxy for the prediction of disease severity,with higher SMN2 copy number typically being associated with reduced severity.of SMA,although this relationship is not absolute:some individuals with low SMN2 copy number have less severe SMA phenotypes and vice ***,the etiology.of SMA is further complicated by.other factors,such as non-typical nucleotide variants and SMN2-independent modifiers of disease severity.

关键词： atrophy traditionally absolute

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Effects of building aspect ratio,diurnal heating scenario,and wind speed on reactive pollutant dispersion in urban street canyons

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Journal of Environmental Sciences 2012年第12期24卷 2091-2103页

作者： Nelson y.o.Tong Dennis y.C.Leung Department of Mechanical Engineering The University of Hong Kong

A photochemistry coupled computational fluid dynamics （CFD） based numerical model has been developed to model the reactive pollutant dispersion within urban street canyons, particularly integrating the interrelationship among diurnal heating scenario （solar radiation affections in nighttime, daytime, and sun-rise/set）, wind speed, building aspect ratio （building-height-to-street-width）, and dispersion of reactive gases, specifically nitric oxide （No）, nitrogen dioxide （No2） and ozone （o3） such that a higher standard of air quality in metropolitan cities can be achieved. Validation has been done with both experimental and numerical results on flow and temperature fields in a street canyon with bottom heating, which justifies the accuracy.of the current model. The model was applied to idealized street canyons of different aspect ratios from 0.5 to 8 with two different ambient wind speeds under different diurnal heating scenarios to estimate the influences of different aforementioned parameters on the chemical evolution of No, No2 and 03. Detailed analyses of vertical profiles of pollutant concentrations showed that different diurnal heating scenarios could substantially affect the reactive gases exchange between the street canyon and air aloft, followed by respective dispersion and reaction. Higher building aspect ratio and stronger ambient wind speed were revealed to be, in general, responsible for enhanced entrainment of 03 concentrations into the street canyons along windward walls under all diurnal heating scenarios. Comparatively, particular attention can be paid on the windward wall heating and nighttime uniform surface heating scenarios.

关键词： photochemistry reactive pollutant dispersion building aspect ratio diurnal heating scenario wind speed urban streetcanyon

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Thermal efficiency.of the principal greenhouse gases

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Chinese Physics B 2015年第1期24卷 195-200页

作者： A.y.Galashev o.R.Rakhmanova Institute of Industrial Ecology Ural Branch Russian Academy of Sciences Yekaterinburg 620990 Russia

Atmospheric gases are ranked according to the efficiency with which they absorb and radiate longwave radiation. The open international HITRAN database of gaseous absorption lines of high resolution together with inverse Fourier transform were used. The autocorrelation functions of the total dipole moment of the basic greenhouse gases molecules such as H2 o,Co2, o3, N2 o, and CH4 were obtained. Absorption coefficient spectra and emission power spectra of infrared radiation of these gases were calculated. Analysis of the emissive ability.of all gases under consideration was carried out. Compared to Co2, all the gases under investigation have more effective emission except ozone. An efficiency criterion of IR absorption and emission is defined and is calculated for each studied gas, and the gases are ranked accordingly as follows（from strong to weak）： H2 o, CH4, Co2, N2 o, and o3.

关键词： greenhouse gases absorption and emission spectra efficiency criterion

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Cretaceous volcanic-intrusive magmatism in western Guangdong and its geological significance

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Science China Earth Sciences 2006年第7期49卷 696-713页

作者： S. y. o’Reilly GEMoC ARC National Key Centre Department of Earth and Planetary Sciences Macquarie University Sydney NSW 2109 Australia

Systematic zircon LA-ICPMS U-Pb dating reveals that Cretaceous volcanic-intrusive activities developed in western Guangdong. Representative volcanic rocks, i.e. Maanshan and Zhougongding rhyodacites, have zircon U-Pb isotopic ages of 100±1 Ma, and the intrusive ones in-cluding the Deqing monzonitic granite body and the Xinghua granodiorite body in the Shidong com-plex, as well as the Tiaocun granodiorite body in the Guangping complex yield ages of 99±2 Ma, ca. 100 Ma, and 104±3 Ma respectively. The biotite-granites of the Shidong complex main body (461±35 Ma) and that of the Guangping complex (444±6 Ma) are Caledonian. In spite of the big time interval between Cretaceous volcanic-intrusive magmatisms and Caledonian intrusive ones, both of them are characterized by enrichment in Rb, Th, Ce, Zr, Hf, Sm, depletion in Ba, Nb, Ta, P, Ti, Eu, and weakly REE tetrad effect. Eu negative anomalies are: Cretaceous volcanic rocks (Eu/Eu*=0.74), Cretaceous intrusive rocks (Eu/Eu*=0.35―0.58), Caledonian biotite granites (Eu/Eu*=0.31―0.34). Studies of Sr-Nd isotope data show that all these igneous rocks have high initial 87Sr/86Sr ratios (0.7105―0.7518), and low εNd(t) values (?7.23―?11.39) with their Nd two-stage model ages ranging from 1.6―2.0 Ga, which suggest that they all derived from the Proterozoic crustal basement of southeast China. The occurrence of Cretaceous volcanic-intrusive magmatisms in western Guangdong is related with the important lithospheric extension event in southeast China (including Nanling region) at ca. 100 Ma. The “volcanic line” defined by the large scale Mesozoic intermediate-acidic volcanic magmatisms in southeast China may further extend to the southwest margin of Nanling region.

关键词： Cretaceous, volcanic-intrusive rocks, zircon U-Pb dating, Sr-Nd isotope, western Guangdong.

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Tool geometry based prediction of critical thrust force while drilling carbon fiber reinforced polymers

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Advances in Manufacturing 2015年第4期3卷 300-308页

作者： y. Karpat o. Bahtiyar Department of Industrial Engineering Bilkent UniversityAnkara 06800 Turkey Turkish Aerospace Industries Inc. Ankara 06980 Turkey

Carbon fiber reinforced polymers （CFRPs） are known to be difficult to cut due to the abrasive nature of carbon fibers and the low thermal conductivity.of the polymer matrix. Polycrystalline diamond （PCD） drills are commonly employed in CFRP drilling to satisfy hole quality conditions with an acceptable tool life. Drill geometry is known to be influential on the hole quality and productivity.of the process. Considering the variety.of CFRP laminates and available PCD drills on the market, selecting the suitable drill design and process parameters for the CFRP material being machined is usually per- formed through trial and error, In this study, machining performances of four different PCD drills are investigated. A mechanistic model of drilling is used to reveal trade-offs in drill designs and it is shown that it can be used to select suitable feed rate for a given CFRP drilling process.

关键词： Machining Drilling - Carbon fiber reinforced polymer (CFRP) Polycrystalline diamond (PCD) Delamination

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Computer simulation of the bombardment of a copper film on graphene with argon clusters

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Chinese Physics B 2015年第2期24卷 105-108页

作者： A.y.Galashev o.R.Rakhmanova Institute of Industrial Ecology Ural BranchRussian Academy of Sciences

The process of graphene cleaning of a copper film by bombarding it with Ar_（13） clusters is investigated by the molecular dynamics *** kinetic energies of the clusters are 5,10,20,and 30 eV and the incident angles are θ= 90°,75°,60°,45°,and 0°.It is obtained that the cluster energy should be in the interval 20 eV-30 eV for effective graphene *** is no cleaning effect at vertical incidence（θ =0°） of Ar_（13） *** bombardments at 45° and 90° incident angles are the most effective on a moderate and large amount of deposited copper,respectively.

关键词： argon cluster bombardment copper film graphene

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