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Sources of organic matter and paleo-environmental implications inferred from carbon isotope compositions of lacustrine sediments at Inexpressible Island, Ross Sea, Antarctica

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Advances in Polar Science 2016年第4期27卷 233-244页

作者： WEI Yangyang JIN Jing NIE Yaguang CHEN Xin WU Libin FU Pingqing LIU Xiaodong steven d.emslie Institute of Polar Environment School of Earth and Space Sciences University of Science and Technology of China Key Laboratory of Ion Beam Bioengineering Hefei Institutes of Physical Science Chinese Academy of SciencesKey Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province LAPC Institute of Atmospheric Physics Chinese Academy of Sciences department of Biology and Marine Biology University of North Carolina Wilmington

The carbon isotopic composition of organic matter （δ^13Corg） was determined in two sediment cores （IIL1 and IIL9） recovered from Inexpressible Island, Ross Sea, Antarctica, and analyzed to identify the sources of that organic matter. The δ^13Corg values of sediments of IIL9 were found to vary between -14.6‰ and -11.6‰, with a mean of-13.4‰ （n=48）. These values were significantly higher than those of IIL1 sediments which varied between -23.2‰ and -20.4‰, with a mean of-21.8%o （n=55）. The variation in δ^13Corg values in these two sediment cores indicate different sources of organic matter, The relatively high 6~3Corg values in IIL9 are in accordance with a source from algae, while the low δ^13Corg values in IIL1 evince significant influence from penguin guano with algae as the secondary source. Compared with the reference data from other high-latitude lake sediments and plants, the δ^13Corg values in IIL9 were extremely high, a result likely related to intense competition for CO2 assimilation among algal species during the growing season in this relatively shallow pond. These results indicate that sedimentary δ^13Corg is a reliable proxy for paleo-primary productivity in ponds at Inexpressible Island.

关键词： Inexpressible Island Ross Sea pond sediments lake algae carbon isotopic composition paleo-environment

Carbon isotope ratios of n-alkanoic acids: new organic proxies for paleo-productivity in Antarctic ponds

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Advances in Polar Science 2023年第4期34卷 304-317页

作者： CHEN Xin JIN Jing NIE Yaguang ZHANG Jifeng dONG Liang HUANG Xianyu steven demslie LIU Xiaodong Anhui Province Key Laboratory of Polar Environment and Global Change School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200030China Key Laboratory for Polar Ecosystem and Climate Change of Ministry of Education School of OceanographyShanghai Jiao Tong UniversityShanghai 200030China Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China Research Center for Ecology College of ScienceTibet UniversityLhasa 850000China Key Laboratory of Polar Science MNRPolar Research Institute of ChinaShanghai 200136China Hubei Key Laboratory of Critical Zone Evolution School of Geography and Information EngineeringChina University of GeosciencesWuhan 430078China department of Biology and Marine Biology University of North CarolinaWilmingtonNC 28403USA

Primary productivity in the Antarctic aquatic environment with simple ecosystems is sensitive to climate and environmental *** investigatedδ13C values for n-alkanoic acids derived from phototrophic organisms in a lacustrine sediment core(IIL3)to indicate primary productivity in ponds on Inexpressible Island in the western Ross Sea,***-chain n-alkanoic acids(C14–C18)were abundant in the IIL3 sediment *** carbon isotope ratios of short-chain n-alkanoic acids in the sediment samples and floating microbial mats were similar,indicating that the short-chain n-alkanoic acids in the IIL3 sediment profile predominantly originated from phototrophic ***δ13C values for the short-chain n-alkanoic acids varied widely through the sediment profile,and 13C-enrichment of n-alkanoic acids was most likely related to high productivity due to carbon-limited conditions caused by enhanced photosynthetic ***δ13C values for the n-alkanoic acids changed over the past 3200 years in similar ways to organic proxies for aquatic productivity(n-alkanoic acid and sterol sedimentary fluxes).C16 n-alkanoic acid was enriched in 13C in periods of high aquatic productivity~750–1650 and 3000–3200 a BP but depleted in 13C in periods of relatively low productivity~150–600 and 2500–3000 a *** results indicated that carbon isotope ratios of lipids from phototrophic organisms could be used as new proxies to reconstruct paleo-productivity in Antarctic lakes and ponds and therefore improve our understanding of past climate changes.

关键词： East Antarctica lipid biomarkers carbon isotopic ratios pond primary productivity climate change

Einstein’s Concept of Clock Synchronization Conflicts with the Second Relativity Postulate

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Journal of Modern Physics 2024年第7期15卷 985-1000页

作者： steven d. deines donatech Corporation Inc. Fairfield Iowa USA

Einstein defined clock synchronization whenever photon pulses with timetags traverse a fixed distance between two clocks with equal time spans ineither direction. Using the second relativity postulate, he found clocksmounted on a rod uniformly moving parallel with the rod’s length cannot besynchronized, but clocks attached to a stationary rod can. He dismissed thisdiscrepancy by claiming simultaneity and clock synchronization were not commonbetween inertial frames, but this paper proves with both Galilean and Lorentztransformations that simultaneity and clock synchronization are preservedbetween inertial frames. His derivation means moving clocks can never besynchronized in a “resting” inertial frame. Ultraprecise atomic clocks intimekeeping labs daily contradict his results. No algebraic error occurred inEinstein’s derivations. The two cases of clocksattached to a rod reveal three major conflicts with the currentsecond postulate. The net velocity between a photon source and detector plusthe “universal” velocity c is mathematically equivalent toEinstein’s clock synchronization method. As the ultraprecise timekeepingcommunity daily synchronizes atomic clocks on the moving Earth withultraprecise time uncertainty well below Einstein’s lowest limit ofsynchronization, the theoretical resolution of the apparent conflict isaccomplished by expanding the second relativity postulate to incorporate thenet velocity between the photon source and detector with the emitted velocity c as components of the total velocity c. This means the magnitudeof the total photon velocity can exceed the speed limit (299792458 m/s) set by the standard velocity c. .

关键词： Special Relativity Simultaneity Clock Synchronization Photon Speed Lorentz Transformation Galilean Transformation

Relational and Euclidean Temporal Space

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Journal of Applied Mathematics and Physics 2024年第2期12卷 683-719页

作者： steven d. P. Moore Independent Researcher Milton Canada

In mathematics, space encompasses various structured sets such as Euclidean, metric, or vector space. This article introduces temporal space—a novel concept independent of traditional spatial dimensions and frames of reference, accommodating multiple object-oriented durations in a dynamical system. The novelty of building temporal space using finite geometry is rooted in recent advancements in the theory of relationalism which utilizes Euclidean geometry, set theory, dimensional analysis, and a causal signal system. Multiple independent and co-existing cyclic durations are measurable as a network of finite one-dimensional timelines. The work aligns with Leibniz’s comments on relational measures of duration with the addition of using discrete cyclic relational events that define these finite temporal spaces, applicable to quantum and classical physics. Ancient formulas have symmetry along with divisional and subdivisional orders of operations that create discrete and ordered temporal geometric elements. Elements have cyclically conserved symmetry but unique cyclic dimensional quantities applicable for anchoring temporal equivalence relations in linear time. We present both fixed equivalences and expanded periods of temporal space offering a non-Greek calendar methodology consistent with ancient global timekeeping descriptions. Novel applications of Euclid’s division algorithm and Cantor’s pairing function introduce a novel paired function equation. The mathematical description of finite temporal space within relationalism theory offers an alternative discrete geometric methodology for examining ancient timekeeping with new hypotheses for Egyptian calendars.

关键词： Relationalism Pairing Function Equation discrete Euclidean Timelines Ancient Timekeeping

Friction and wear performance of polyether ether ketone(PEEK)polymers in three lubrication regimes

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Friction 2024年第4期12卷 670-682页

作者： davide MASSOCCHI Nora LECIS Marco LATTUAdA davide SCAGLIA steven CHATTERTON Paolo PENNACCHI department of Mechanical Engineering Politecnico di MilanoMilan 20156Italy Eni SpA Downstream product R&DLombardia 20097Italy Eurobearings S.R.L. Lombardia 29016Italy

This experimental study investigates the friction and wear of three coatings commonly used in industrial applications,particularly in hydrodynamic *** three materials under investigation were Babbitt,polyether ether ketone(PEEK)reinforced with 15%carbon fibers,and PEEK reinforced with 20%carbon *** first polymer material was extruded,while the other was produced by fused deposition modelling(FdM).The materials were subjected to sliding tests in a pin-on-disc configuration,with a steel ball serving as the counter *** tests were conducted at room temperature,with a load of 10 N and under three different lubrication conditions:dry,grease,and *** linear speed was set at 0.3 m/s for the dry and semi-solid lubrication tests,while for the oil tests,the speed was set at 0.25 m/*** greases used had consistency grades of NGLI 000 and NGLI *** ISO VG 68 circulation oil was used for the oil lubrication ***,thermodynamic analyses were performed under the most severe conditions(i.e.,dry)to investigate the steel-Babbitt and steel-PEEK contact.

关键词： hydrodynamic bearings polyether ether ketone(PEEK)polymers additive manufacturing grease lubrication sliding oil lubrication ball-on-disk tribology

Exploring unconventional attributes of red blood cells and their potential applications in biomedicine

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Protein & Cell 2024年第5期15卷 315-330页

作者： Alkmini T.Anastasiadi Vasiliki-Zoi Arvaniti Krystalyn E.Hudson Anastasios G.Kriebardis Constantinos Stathopoulos Angelo d’Alessandro steven L.Spitalnik Vassilis L.Tzounakas department of Biochemistry School of MedicineUniversity of Patras26504 PatrasGreece department of Pathology and Cell Biology Columbia University Irving Medical CenterNew York CityNY 10032USA Laboratory of Reliability and Quality Control in Laboratory Hematology(HemQcR) Department of Biomedical SciencesSchool of Health&Caring SciencesUniversity of West Attica(UniWA)12243 EgaleoGreece department of Biochemistry and Molecular Genetics University of Colorado Anschutz Medical Campus13001 AuroraCOUSA Present address:Institute for Fundamental Biomedical Research(IFBR) Biomedical Sciences Research Center“Alexander Fleming”Vari11527 AthensGreece

We need to talk about red blood *** cells are defined as cells containing distinct nuclei and other membranous ***,red blood cells(RBCs)lack a nucleus and organelles—perhaps to limit the generation of reactive oxygen species(Zhang et al.,2011)—and are filled with hemoglobin(Hb).This oxygen carrier is limited to the cytosol by the cell membrane and cytoskeleton,which maintain cellular integrity and deformability as RBCs pass through narrow capillaries(Gratzer,1994)to perform their primary function of gas exchange.

关键词： membranous maintain

Hepatic angiotensin-converting enzyme 2 expression in metabolic dysfunction-associated steatotic liver disease and in patients with fatal COVId-19

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World Journal of Gastroenterology 2024年第31期30卷 3705-3716页

作者： Angus K Jacobs steven d Morley Kay Samuel Katie Morgan Lyndsey Boswell Timothy J Kendall david A dorward Jonathan A Fallowfield Peter C Hayes John N Plevris Hepatology Laboratory University of EdinburghEdinburgh EH164SBUnited Kingdom Scottish National Blood Transfusion Service Jack Copland CentreEdinburgh EH144BEUnited Kingdom Institute for Regeneration and Repair University of EdinburghEdinburgh EH164UUUnited Kingdom Edinburgh Pathology University of EdinburghEdinburgh EH164SBUnited Kingdom

BACKGROUNd Metabolic dysfunction-associated steatotic liver disease(MASLd),characterised by hepatic lipid accumulation,causes inflammation and oxidative stress accompanied by cell damage and *** injury(LI)is also frequently reported in patients hospitalised with coronavirus disease 2019(COVId-19),while preexisting MASLd increases the risk of LI and the development of COVId-19-associated *** of injury at the cellular level remain unclear,but it may be significant that severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)which causes COVId-19,uses angiotensin-converting expression enzyme 2(ACE2),a key regulator of the‘anti-inflammatory’arm of the renin-angiotensin system,for viral attachment and host cell *** To determine if hepatic ACE2 levels are altered during progression of MASLd and in patients who died with severe *** ACE2 protein levels and localisation,and histological fibrosis and lipid droplet accumulation as markers of MASLd were determined in formalin-fixed liver tissue sections across the MASLd pathological spectrum(isolated hepatocellular steatosis,metabolic dysfunction-associated steatohepatitis(MASH)+/-fibrosis,end-stage cirrhosis)and in post-mortem tissues from patients who had died with severe COVId-19,using ACE2 immunohistochemistry and haematoxylin and eosin and picrosirius red staining of total collagen and lipid droplet areas,followed by quantification using machine learning-based image pixel *** ACE2 staining is primarily intracellular and concentrated in the cytoplasm of centrilobular hepatocytes and apical membranes of bile duct ***,ACE2 protein levels are elevated in non-fibrotic MASH compared to healthy controls but not in the progression to MASH with fibrosis and in ***2 protein levels and histological fibrosis are not associated,but ACE2 and liver lipid droplet content are significantly correlated across the MASLd *** A

关键词： Metabolic dysfunction-associated steatotic liver disease Angiotensin-converting enzyme 2 Immunohistochemistry COVId-19 COVId-19-associated cholangiopathy

Fetal lung growth predicts the risk for early-life respiratory infections and childhood asthma

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World Journal of Pediatrics 2024年第5期20卷 481-495页

作者： dimitra E.Zazara Olympia Giannou steven Schepanski Mirja Pagenkemper Anastasios d.Giannou Maike Pincus Ioannis Belios Stefan Bonn Ania C.Muntau Kurt Hecher Anke diemert Petra Clara Arck division for Experimental Feto-Maternal Medicine Department of Obstetrics and Fetal MedicineUniversity Medical Center Hamburg-Eppendorf(UKE)Martinistraße 5220251HamburgGermany University Children’s Hospital UKEHamburgGermany Computer Engineering and Informatics department Polytechnic SchoolUniversity of PatrasPatrasGreece Institute of developmental Neurophysiology Center for Molecular Neurobiology Hamburg(ZMNH)UKEHamburgGermany department of Obstetrics and Fetal Medicine UKEHamburgGermany department of General Visceral and Thoracic SurgeryUKEHamburgGermany Section of Molecular Immunology and Gastroenterology Ⅰ.Department of MedicineUKEHamburgGermany Pediatrics and Pediatric Pneumology Practice BerlinGermany Institute of Medical Systems Biology ZMNHUKEHamburgGermany Hamburg Center for Translational Immunology UKEHamburgGermany

Background Early-life respiratory infections and asthma are major health burdens during *** predicting an increased risk for early-life respiratory diseases are ***,we identified the predictive value of ultrasound-monitored fetal lung growth for the risk of early-life respiratory infections and *** Fetal lung size was serially assessed at standardized time points by transabdominal ultrasound in pregnant women participating in a pregnancy *** between fetal lung growth and respiratory infections in infancy or early-onset asthma at five years were ***-learning models relying on extreme gradient boosting regressor or classifier algorithms were developed to predict respiratory infection or asthma risk based on fetal lung *** model development and validation,study participants were randomly divided into a training and a testing group,respectively,by the employed *** Enhanced fetal lung growth throughout pregnancy predicted a lower early-life respiratory infection *** sex was associated with a higher risk for respiratory infections in *** lung growth could also predict the risk of asthma at five years of *** designed three machine-learning models to predict the risk and number of infections in infancy as well as the risk of early-onset *** models’R2 values were 0.92,0.90 and 0.93,respectively,underscoring a high accuracy and agreement between the actual and predicted *** variables included known risk factors and novel predictors,such as ultrasound-monitored fetal lung *** Sonographic monitoring of fetal lung growth allows to predict the risk for early-life respiratory infections and asthma.

关键词： Asthma Child risk Early-life respiratory infections Prenatal lung development Sexual dimorphism

Elaborations of the influencing factors on the formation of secondary inorganic aerosols in a heavily polluted urban area of China

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Journal of Environmental Sciences 2024年第4期138卷 406-417页

作者： Shuang Wang Qiyuan Wang Ting Zhang Suixin Liu steven Sai Hang Ho Jie Tian Hui Su Yong Zhang Luyao Wang Tingting Wu Junji Cao School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an 710049China Key Laboratory of Aerosol Chemistry and Physics State Key Laboratory of Loess and Quaternary GeologyInstitute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China CAS Center for Excellence in Quaternary Science and Global Change Xi’an 710061China National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain Xi’an 710061China division of Atmospheric Sciences Desert Research InstituteRenoNevada89512United States Hong Kong Premium Services and Research Laboratory KowloonHong Kong SARChina Xi’an Institute for Innovative Earth Environment Research Xi’an 710061China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China

In this study,online water-soluble inorganic ions were detected to deduce the formation mechanism of secondary inorganic aerosol in Xianyang,China during *** dominant inorganic ions of sulfate(SO_(4)^(2-)),nitrate(NO_(3)^(-)),and ammonium(NH_(4)^(+))(the sum of those is abbreviated as SNA)accounted for 17%,21%,and 12% of PM_(2.5)mass,*** the air quality deteriorated from excellent to poor grades,the precursor gas sulfur dioxide(SO_(2))of SO_(4)^(2-)increased and then decreased with a fluctuation,while nitrogen dioxide(NO_(2))and ammonia(NH_(3)),precursors of NO_(3)^(-)and NH_(4)^(+),and SNA show increasing *** factors including boundary layer height(BLH),temperature,and wind speed also show decline trends,except relative humidity(RH).Meanwhile,the secondary conversion ratio shows a remarkable increasing trend,indicating that there was a strong secondary *** the perspective of chemical mechanisms,RH is positively correlated with sulfur oxidation ratios(SOR),nitrogen oxidation ratios(NOR),and ammonia conversion ratios,representing that the increase of humidity could promote the generation of ***,SOR and NOR were also positively related to the *** the one hand,the low wind speed and BLH led to the accumulation of *** the other hand,the increases of RH and ammonia promoted more formations of SNA and PM_(2.5).The results advance our identification of the contributors to the haze episodes and assist to establish more efficient emission controls in Xianyang,in addition to other cities with similar emission and geographical characteristics.

关键词： Haze episodes Secondary inorganic aerosol Secondary conversion ratio Meteorological factors