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Rare-earth and trace elements and hydrogen and oxygen isotopic compositions of Cretaceous kaolinitic sediments from the Lower Benue trough, Nigeria: provenance and paleoclimatic significance

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Acta Geochimica 2019年第3期38卷 350-363页

作者： Anthony t.Bolarinwa Sunday O.Idakwo david L.Bish Department of Geology University of Ibadan Department of Earth Sciences Kogi State University Department of Geological Sciences Indiana University

this study evaluated the Cretaceous(Campanian–Maastrichtian) kaolinitic sediments of the Ajali/Mamu and Enugu/Nkporo Formations from the Lower Benue trough of Nigeria. A combined method of inductively coupled plasma–mass spectrometry and isotope ratio mass spectrometry was used to investigate trace and rareearth element geochemistry and hydrogen and oxygen isotopic compositions. these data were then used to infer the sediments' provenance and paleoclimatic conditions during their deposition. the sediments contained low concentrations of most trace elements, with the exceptions of Zr(651–1352 ppm), Ba(56–157 ppm), V(38–90 ppm),and Sr(15.1–59.6 ppm). Average values of Co and Ni were1.5 and 0.7 ppm, respectively. trace and rare earth element values were lower than corresponding values for upper continental crust and Post-Archean Australian Shale, with the exception of Zr. the samples showed only slight light rare-earth enrichment and nearly flat heavy rare-earth depletion patterns, with negative Eu and tm anomalies,typical of felsic sources. Geochemical parameters such as La/Sc, th/Sc, and th/Co ratios support that the kaolinitic sediments were derived from a felsic rock source, likely deposited in an oxic environment.^(18 )O values ranged from+ 15.4 to + 21.2% for the investigated samples, consistent with a residual material derived from chemicalweathering of felsic rock and redeposited in a sedimentary basin(typical values of + 19 to + 21.2%). While in the basin, the sediments experienced extended interactions with meteoric water enriched in d D and d16 O. However,the variation in d D and d16 O values for the investigated samples is attributed to the high temperature of formation(54–91 °C). the d D and d^(18 )O values suggest that the sediments, although obtained from different localities within the Lower Benue trough, formed under similar hot,tropical climatic conditions.

关键词： Rare-earth and trace elements Oxygen/ hydrogen isotopic composition Kaolinitic sediments Lower Benue trough Nigeria

Mitophagy Regulation in Skeletal Muscle:Effect of Endurance Exercise and Age

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Journal of Science in Sport and Exercise 2019年第3期1卷 228-236页

作者： Avigail t.Erlich david A.Hood Muscle Health Research Centre School of Kinesiology and Health ScienceYork University4700 Keele StTorontoON M3J 1P3Canada

Mitochondria are essential energy-providing organelles that are required in the maintenance of healthy skeletal *** such,the removal of damaged mitochondria,through mitophagy,is necessary to maintain mitochondrial *** aging muscle,mitochondrial content and function are often found to be reduced compared to young *** occurs despite the fact that measures of mitophagy are elevated,suggesting that mitophagy is insufficiently high to remove all of the dysfunctional organelles in aging *** evidence has shown that acute exercise promotes mitophagic signaling,leading to organelle *** exercise-induced signaling is attenuated in aging muscle,suggesting that aging muscle loses its capacity for mitochondrial turnover in response to *** contributes to the reduction in muscle health in elderly *** exercise training improves mitochondrial content and function,even in aging muscle,leading to reduced mitophagy ***,exercise training should be prescribed for both young and elderly populations to pro-mote the maintenance of a healthy mitochondrial pool,through the stimulation of both organelle biogenesis and mitophagy.

关键词： Mitochondria Mitophagy Exercise Aging Lysosomes

Ultrasmall Ag^＋-rich nanoclusters as highly efficient nanoreservoirs for bacterial killing

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维普期刊数据库

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Nano Research 2014年第3期7卷 301-307页

作者： Xun Yuan Magdiel I. Setyawati david t. Leong Jianping Xie Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117576 Singapore

Metallic silver （Ag） and its ability to combat infection have been known since ancient history. In the wake of nanotechnology advancement, silver＇s efficacy to fight broad spectrum bacterial infections is further improved in the form of Ag nanoparticles （NPs）. Recent studies have ascribed the broad spectrum antimicrobial properties of Ag NPs to dissociation of Ag＊ ions from the NPs, which may not be entirely applicable when the size of Ag NPs decreases to the sub-2 nm range [denoted Ag nanoclusters （NCs）]. In this paper we report that ultrasmall glutathione （GSH）-protected Ag^＋-rich NCs （Ag^＋-R NCs for short, with a predominance of Ag＋ species in the NCs） have much higher antimicrobial activities towards both gram-negative and gram-positive bacteria than the reference NC, GSH-Ag^＋-R NCs. they have the same size and surface ligand, but with different oxidation states of the core silver. this interesting finding suggests that the undissociated Ag^＋-R NCs armed with abundant Ag^＋ ions on the surface are highly active in bacterial killing, which was not observed in the system of their larger counterpart, Ag NPs.

关键词： noble metal nanoclusters silver antimicrobial agent biomedicine bacteria

Age and sex specific timing, frequency, and spatial distribution of horseshoe crab spawning in Delaware Bay:Insights from a large-scale radio telemetry array

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Current Zoology 2010年第5期56卷 563-574页

作者： david R.SMItH Lorne J.BROUSSEAU Mary t. MANDt Michael J.MILLARD USGS Leetown Science Center Cornell University Cooperative Extension U.S. Fish and Wildlife Service

to study horseshoe crab Limulus polyphemus spawning behavior and migration over a large-spatial extent （〉100 km）, we arrayed fixed station radio receivers throughout Delaware Bay and deployed radio transmitters and archival tags on adult horseshoe crabs prior to their spawning season. We tagged and released 160 females and 60 males in 2004 and 217 females in 2005. the array covered approximately 140 km of shoreline. Recapture rates were 〉70% with multi-year recaptures. We categorized adult age by carapace wear. Older females tended to spawn earlier in the season and more frequently than young females, but those tendencies were more apparent in 2004 when spawning overall occurred earlier than in 2005 when spawning was delayed possibly due to decreased water temperatures. timing of initial spawning within a year was correlated with water temperature. After adjusting for day of first spring tide, the day of In＇st spawning was 4 days earlier for every 1 degree （℃） rise in mean daily water temperature in May. Seventy nine % of spawning occurred during nighttime high tides. Fifty five % of spawning occurred within 3 d of a spring tide, which was slightly higher than the 47% expected if spawning was uniformly distributed regardless of tidal cycle. Within the same spawning season, males and females were observed spawning or intertidally resting at more than one beach separated by 〉5 kin. Between years, most （77%） did not return to spawn at the same beach. Probability of stranding was strongly age dependent for males and females with older adults experiencing higher stranding rates. Horseshoe crabs staging in the shallow waters east of the channel spawned exclusively along the eastern （N J） shoreline, but those staging west of the channel spawned throughout the bay. Overall, several insights emerged from the use of radio telemetry, which advances our understanding of horseshoe crab ecology and will be useful in conserving the Delaware Bay horseshoe crab population and habita

关键词： Spawning behavior Marine arthropod Xiphosurid Limulus polyphemus Delaware Bay Radio telemetry

Remote heart rate measurement using low-cost RGB face video： a technical literature review

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Frontiers of Computer Science 2018年第5期12卷 858-872页

作者： Philipp V. ROUASt Marc t. P. ADAM Raymond CHIONG david CORNFORtH Ewa LUX Institute of Information Systems and Marketing Karlsruhe Institute of Technology Karlsruhe 76133 Germany School of Electrical Engineering and Computing The University of Newcastle Callaghan NSW 2308 Australia

Remote photoplethysmography （rPPG） allows remote measurement of the heart rate using low-cost RGB imaging equipment. In this study, we review the development of the field of rPPG since its emergence in 2008. We also classify existing rPPG approaches and derive a framework that provides an overview of modular steps. Based on this framework, practitioners can use our classification to design algorithms for an rPPG approach that suits their specific needs. Researchers can use the reviewed and classified algorithms as a starting point to improve particular features of an rPPG algorithm.

关键词： affective computing heart rate measurement remote non-contact camera-based photoplethysmography

Brains for Dementia Research: the Importance of Cohorts in Brain Banking

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维普期刊数据库

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Neuroscience Bulletin 2019年第2期35卷 289-294页

作者： Paul t.Francis Gillian M.Hayes Helen Costello david R.Whitfield Wolfson Centre for Age-Related Diseases King's College London

Background:the Historical Importance of Studies of Human Brain in Dementia Research the collection of brain and related tissue has a long history(1)In terms of dementia,a more systematic examination of the relationship between brain pathology and clinical symptoms can be traced to Alois Alzheimer’s group in Munich in the early 1900s(2)the use of human brain tissue is essential to increase our understanding of dementia as it gives us the gold standard of disease pathogenesis and clues as to the molecular mechanisms that underpin the various diseases and conditions.

关键词： Importance of Cohorts Dementia Research mechanisms

Search for potential K ion battery cathodes by first principles

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Journal of Energy Chemistry 2021年第3期30卷 377-385页

作者： Kaining Li Xiaofeng Fan david J.Singh WtZheng Key Laboratory of Automobile Materials(Jilin University) Ministry of Educationand College of Materials Science and EngineeringJilin UniversityChangchun 130012JilinChina Department of Physics and Astronomy University of MissouriColumbiaMO 65211-7010USA Department of Chemistry University of MissouriColumbiaMO 65211USA State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130012JilinChina

An important challenge facing K-ion batteries lies in exploring earth-abundant and safe cathode materials that can provide high capacity with high migration rate of K ***,we propose a simple and efficient method for searching potential K cathode materials with first principles *** screening is based on combinations of weight capacity,K ion occupation ratio,volume change per K,and valence *** this screening method we predicted a series of potential K ions cathodes with favorable electrochemical performance,such as K_(2)VPO_(4)CO_(3)-like structures with 1 D diffusion channels,3 D channel structures K_(2)CoSiO_(4),layered materials KCoO_(2),KCrO_(2),KVF_(4) and K_(5)V_(3)F_(14),and *** potential cathodes have small volume changes,suitable voltage,and high capacity,with small diffusion *** may be useful in K-ion batteries with high energy density and rate performance.

关键词： K ion battery Cathodes First principles calculations High capacity with high migration rate Diffusion barriers

typology of Natural Hazards and Assessment of Associated Risks in the Mount Bambouto Caldera(Cameroon Line,West Cameroon)

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Acta Geologica Sinica(English Edition) 2009年第5期83卷 1008-1016页

作者： Ghislain t.ZANGMO Armand D.KAGOU david G.NKOUAtHIO Pierre WANDJI Department of Earth Science Faculty of ScienceUniversity of DschangCameroon Laboratory of Geology High Teacher Training SchoolUniversity of Yaounde ICameroon

Mount Bambouto is a polygenic stratovolcano of the Cameroon Volcanic Line, built between 21 Ma and 4.5 Ma. It is situated approximately 200 km NE of Mount Cameroon, between 09° 55＇ and 10°15＇ longitude east and, 05°25＇ and 05°50＇ latitude north. the volcano covers an area of 500 km^2 and culminates at 2740 m at Meletan dome and bears a collapsed caldera at the summit （13 × 8 km）. Mount Bambouto is characterized by several natural hazards of different origins： meteorological, such as landslides and rock falls; anthropogenic, such as bushfires, tribal wars and deforestation; and volcanological, such as volcanic eruption. the thematic map shows that 55-60% of the caldera has high probability of occurrence of mass movement. the caldera has a high population density （3000 inhabitants）, which increases the level of risk, evaluated at approximately $US3.8 million for patrimony, 3000 civilian deaths and destruction of biodiversity.

关键词： caldera hazard risk assessment Mount Bambouto Cameroon Line

Calibration methodology for microscopic traffic simulation models of land ports of entry along the US-Mexico border

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International Journal of Modeling, Simulation, and Scientific Computing 2020年第3期11卷 40-59页

作者： david Salgado Peter t.Martin Abhisek Mudgal Rafael M.Aldrete texas A&M transportation Institute 4050 Rio Bravo Drive Suite 212El Paso 79912USA New Mexico State University Engineering Complex II Rm.215Las Cruces 88003USA Indian Institute of technology(BHU)Civil Engineering Department Varanasi 221011 Uttar PradeshIndia

Non-commercial Land Ports of Entry(LPOEs)are unique transportation facilities controlling the ingress and egress of passenger vehicles from Mexico to the United States and vice *** calibration of microscopic traffic simulation models of non-commercial LPOEs requires a deep understanding of operational processes and driving behavior at these *** paper provides a methodology to guide modelers in calibrating microscopic traffic simulation models of non-commercial *** methodology establishes a common framework for modeling operational processes and traffic ***,the methodology includes the value of four state variables that characterizes operations of passenger vehicles at non-commercial *** variables are speed,acceleration,deceleration,and *** authors evaluated this methodology using the Otay Mesa non-commercial LPOE as a case *** showed that this methodology could be potentially used to model non-commercial LPOEs along the US-Mexico border and other border regions worldwide.

关键词： Land port of entry microsimulation calibration traffic models car-following models state variables