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New evidence for enhanced cosmogenic isotope production rate in the atmosphere ≈37 kaBP from the Guliya ice core

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Chinese Science Bulletin 1999年第17期44卷 1616-1620页

作者： L.G.Thompson E.Mosley-Thompson j.Cole-Dai M.E.davis P.-N.Lin Hyrd Polar Research Center Ohio State University OH 45701 USAHyrd Polar Research Center Ohio State University OH 45701 USAHyrd Polar Research Center Ohio State University OH 45701 USAHyrd Polar Research Center Ohio State University OH 45701 USAHyrd Polar Research Center Ohio State University OH 45701 USA

A 36CI peak was found in the predicted section of Guliya ice core, from the Qinghai-Tibetan Plateau, at about 37 kaBP. This cannot be interpreted by means of changes in the accumulation rate, but by the enhanced cosmogenic isotope production rate in the atmosphere. Compared with the records of 10Be and 36CI in the other regions, the peaks of the cosmogenic isotopes are global and can be considered as time marks. An intriguing fact is that the peaks coincided with cold periods.

关键词： Guliya ice core cosmogenic isotope 36Cl global event climatic change.

Is analysis of lower esophageal sphincter vector volumes of value in diagnosing gastroesophageal reflux disease?

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World journal of Gastroenterology 2003年第1期9卷 174-178页

作者： Robert E.Marsh Christopher L.Perdue Ziad T.Awad Patrice Watson Mohamed Selima Richard E.davis Charles j.Filipi Department of Surgery Creighton University School of MedicineOmaha Nebraska USA Department of Preventive Medicine Creighton University School of MedicineOmaha Nebraska USA

AIM:With successful surgical treatment of gastroesophageal reflux disease(GERD),there is interest in understanding the anti-reflux barrier and its mechanisms of *** date, the potential use of vector volumes to predict the DeMeester score has not been adequately explored. METHODS:627 patients in the referral database received esophageal manometry and ambulatory 24-hour pH *** data included LES resting pressure(LESP), overall LES length(OL)and abdominal length(AL),total vector volume(TVV)and intrabdominal vector volume(IVV). RESULTS:In cases where LESP,TVV or IVV were all below normal,there was an 81.4%probability of a positive DeMeester *** cases where all three were normal, there was an 86.9%probability that the DeMeester score would be ***-operating characteristics(ROC) for LESP,TVV and IVV were nearly identical and indicated no useful cut-off *** regression demonstrated that LESP and IVV had the strongest association with a positive DeMeester score;however,the regression formula was only 76.1%accurate. CONCLUSION:While the indices based on TVV,IVV and LESP are more sensitive and specific,respectively,than any single measurement,the measurement of vector volumes does not add significantly to the diagnosis of GERD.

关键词： Adolescent Adult Aged Aged, 80 and over Child Child, Preschool Esophagogastric junction Female Gastroesophageal Reflux Humans Hydrogen-Ion Concentration Male Manometry Middle Aged ROC Curve Regression Analysis

Early onset of a microcystin-producing cyanobacterial bloom in an agriculturally-influenced Great Lakes tributary

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journal of Oceanology and Limnology 2018年第4期36卷 1112-1125页

作者： Robert Michael L.McKAY Taylor TUTTLE Laura A.REITZ George S.BULLERjAHN William R.CODY Adam j.McDOWELL Timothy W.davis Department of Biological Sciences Bowling Green State University Bowling Green OH 43403 USA Aquatic Taxonomy Specialists Malinta OH 43535 USA City of Defiance Water Division Defiance OH 43512 USA NOAA Great Lakes Environmental Research Laboratory Ann Arbor MI USA

In late May 2016, a cyanobacterial harmful algal bloom(cHAB) was detected in the Maumee River, the largest tributary to Lake Erie, the southernmost lake of the Laurentian Great Lakes system. Testing on 31 May identified Planktothrix agardhii as the dominant cyanobacterium with cell abundance exceeding 1.7×10~9 cells/L and total microcystins(MC) reaching 19 μg/L MC-LR equivalents, a level over 10-fold higher than the 2015 revised U.S. Environmental Protection Agency(EPA) national health advisory levels for drinking water exposure to adults. Low river discharge coincident with negligible precipitation through the latter half of May coincided with an 80% decline in river turbidity that likely favored bloom formation by a low-light adapted P. agardhii population. Also contributing to the c HAB were high initial nutrient loads and an increase of the river temperature from 13℃ to 26℃ over this same period. The bloom persisted through 5 june with microcystins exceeding 22 μg/L MC-LR equivalents at the bloom peak. By 6 june, the river had returned to its muddy character following a rain event and sampling on 7 june detected only low levels of toxin(<0.6 μg/L) at public water systems located near the bloom origin. The elevated toxin production associated with this early onset bloom was without precedent for the Maumee River and an unique attribute of the c HAB was the high proportion of potentially-toxic genotypes. Whereas Planktothrix spp. is common in lotic environments, and has been previously detected in the Maumee, blooms are not commonly reported. This early onset, microcystin-producing c HAB provided a rare opportunity to glean insights into environmental factors that promote bloom development and dominance by Planktothrix in lotic environments.

关键词： cyanobacteria microcystin Planktothrix qPCR river

Rapid, cost-effective DNA quantification via a visuallydetectable aggregation of superparamagnetic silicamagnetite nanoparticles

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Nano Research 2014年第5期7卷 755-764页

作者： Qian Liu jingyi Li Hongxue Liu Ibrahim Tora Matthew S. Ide jiwei Lu Robert j. davis David L. Green james P. Landers Department of Chemistry University of Virginia McCormick Road P. O. Box 400319 Charlottesville 22904 Virginia USA Department of Pathology University of Virginia Health Science Center Charlottesville 22908 Virginia USA Department of Mechanical Engineering University of Virginia Charlottesville 22904 Virginia USA Center for Microsystems forthe Life Sciences University of Virginia Charlottesville 22904 Virginia USA Department of Materials Science & Engineering University of Virginia P. O. Box 400745 395 McCormick Road Charlottesville 22904-4745 Virginia USA Department of Chemical Engineering University of Virginia. 123 Engineers Way Charlottesville 22904 Virginia USA

DNA and silica-coated magnetic particles entangle and form visible aggregates under chaotropic conditions with a rotating magnetic field, in a manner that enables quantification of DNA by image analysis. As a means of exploring the mechanism of this DNA quantitation assay, nanoscale SiO2-coated Fe304 （Fe3O4@SiO2） particles are synthesized via a solvothermal method. Characterization of the particles defines them to be -200 nm in diameter with a large surface area （141.89 m2/g）, possessing superparamagnetic properties and exhibiting high saturation magnetization （38 emu/g）. The synthesized Fe3O4@SiO2 nanoparticles are exploited in the DNA quantification assay and, as predicted, the nanoparticles provide better sensitivity than commercial microscale Dynabeads for quantifying DNA, with a detection limit of 4 kilobase-pair fragments of human DNA. Their utility is proven using nanoparticle DNA quantification to guide efficient polymerase chain reaction （PCR） amplification of short tandem repeat loci for human identification.

关键词： silica/magnetite core-shell superparamagnetic DNA quantification polymerase chain reaction(PCR)

Pathways of China's PM2.5 air quality 2015–2060 in the context of carbon neutrality

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National Science Review 2021年第12期8卷 63-73页

作者： jing Cheng Dan Tong Qiang Zhang Yang Liu Yu Lei Gang Yan Liu Yan Sha Yu Ryna Yiyun Cui Leon Clarke Guannan Geng Bo Zheng Xiaoye Zhang Steven j.davis Kebin He Ministry of Education Key Laboratory for Earth System Modelling Department of Earth System ScienceTsinghua University Department of Earth System Science University of California Chinese Academy of Environmental Planning joint Global Change Research Institute Pacific Northwest National LaboratoryUniversity Research Court Center for Global Sustainability School of Public PolicyUniversity of Maryland State Key joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua University Institute of Environment and Ecology Tsinghua Shenzhen International Graduate SchoolTsinghua University State Key Laboratory of Severe Weather&Key Laboratory of Atmospheric Chemistry of CMA Chinese Academy of Meteorological Sciences

Clean air policies in China have substantially reduced particulate matter(PM2.5) air pollution in recent years,primarily by curbing end-of-pipe ***,reaching the level of the World Health Organization(WHO) guidelines may instead depend upon the air quality co-benefits of ambitious climate ***,we assess pathways of Chinese PM2.5air quality from 2015 to 2060 under a combination of scenarios that link global and Chinese climate mitigation pathways(*** 2℃-and 1.5℃-pathways,National Determined Contributions(NDC) pledges and carbon neutrality goals) to local clean air *** find that China can achieve both its near-term climate goals(peak emissions) and PM2.5air quality annual standard(35 μg/m~3) by 2030 by fulfilling its NDC pledges and continuing air pollution control ***,the benefits of end-of-pipe control reductions are mostly exhausted by 2030,and reducing PM2.5exposure of the majority of the Chinese population to below 10 μg/m~3 by 2060 will likely require more ambitious climate mitigation efforts such as China’ s carbon neutrality goals and global1.5℃-*** results thus highlight that China’s carbon neutrality goals will play a critical role in reducing air pollution exposure to the level of the WHO guidelines and protecting public health.

关键词： clean air policy carbon neutrality synergy pathway air quality standards WHO guidelines

The global mismatch between equitable carbon dioxide removal liability and capacity

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National Science Review 2023年第12期10卷 111-123页

作者： Pu Yang Zhifu Mi Yi-Ming Wei Steef V.Hanssen Lan-Cui Liu D'Maris Coffman Xinlu Sun Hua Liao Yun-Fei Yao jia-Ning Kang Peng-Tao Wang Steven j.davis The Bartlett School of Sustainable Construction University College London Energy and Power Group University of Oxford Exeter Sustainable Finance Centre University of Exeter Center for Energy and Environmental Policy Research Beijing Institute of Technology School of Management and Economics Beijing Institute of Technology Department of Environmental Science Faculty of Science Radboud University Business School Beijing Normal University Strategy Plan Department Sinopec Research Institute of Petroleum Engineering Department of Earth System Science University of California

Limiting climate change to 1.5℃ and achieving net-zero emissions would entail substantial carbon dioxide removal(CDR) from the atmosphere by the mid-century,but how much CDR is needed at country level over time is *** purpose of this paper is to provide a detailed description of when and how much CDR is required at country level in order to achieve 1.5℃ and how much CDR countries can carry out *** allocate global CDR pathways among 170 countries according to 6 equity principles and assess these allocations with respect to countries’ biophysical and geophysical capacity to deploy *** global CDR to countries based on these principles suggests that CDR will,on average,represent～4% of nations’ total emissions in 2030,rising to ～17% in ***,equitable allocations of CDR,in many cases,exceed implied land and carbon storage *** estimate～15 % of countries(25)would have insufficient land to contribute an equitable share of global CDR,and ～40% of countries(71)would have insufficient geological storage *** more diverse CDR technologies are developed,the mismatch between CDR liabilities and land-based CDR capacities will lead to global demand for six GtCO2carbon credits from 2020 to *** demonstrates an imperative demand for international carbon trading of CDR.

关键词： carbon dioxide removal land-based solutions international equity

Growth and differentiation of human induced pluripotent stem cell(hiPSC)-derived kidney organoids using fully synthetic peptide hydrogels

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Bioactive Materials 2023年第3期21卷 142-156页

作者： Niall j.Treacy Shane Clerkin jessica L.davis Ciar´an Kennedy Aline F.Miller Alberto Saiani jacek K.Wychowaniec Dermot F.Brougham john Crean Diabetes Complications Research Centre University College Dublin(UCD)Conway Institute of Biomolecular and Biomedical Research and BelfieldDublin 4Ireland UCD School of Biomolecular and Biomedical Science BelfieldDublin 4Ireland Department of Materials&Manchester Institute of Biotechnology(MIB) School of Natural SciencesFaculty of Science and EngineeringThe University of ManchesterUK UCD School of Chemistry University College DublinBelfieldDublin 4Ireland

Human induced pluripotent stem cell(hiPSC)-derived kidney organoids have prospective applications ranging from basic disease modelling to personalised ***,there remains a necessity to refine the bio-physical and biochemical parameters that govern kidney organoid *** within fully-controllable and physiologically relevant 3D growth environments will be critical to improving organoid reproducibility and ***,we matured hiPSC-derived kidney organoids within fully synthetic self-assembling peptide hydrogels(SAPHs)of variable stiffness(storage modulus,G′).The resulting organoids con-tained complex structures comparable to those differentiated within the animal-derived matrix,***-cell RNA sequencing(scRNA-seq)was then used to compare organoids matured within SAPHs to those grown within Matrigel or at the air-liquid interface.A total of 13,179 cells were analysed,revealing 14 distinct *** compositional analysis revealed a larger proportion of nephron cell types within Transwell-derived organoids,while SAPH-derived organoids were enriched for stromal-associated cell ***,dif-ferentiation within a higher G’SAPH generated podocytes with more mature gene expression ***-tionally,maturation within a 3D microenvironment significantly reduced the derivation of off-target cell types,which are a known limitation of current kidney organoid *** work demonstrates the utility of syn-thetic peptide-based hydrogels with a defined stiffness,as a minimally complex microenvironment for the selected differentiation of kidney organoids.

关键词： Human kidney organoids Fully synthetic matrices Self-assembling peptide hydrogels Single-cell RNA sequencing

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EDB中微米单颗粒振荡特性

化工学报 2004年第6期55卷 902-906页

作者：冯昭华朱家骅杨雪峰夏素兰关国强 davis E.j 四川大学化学工程学院四川成都610065 华盛顿大学化工系

改进了davis关于微米单颗粒在EDB(electrodynamicbalance)中悬浮的两区理论 ,通过引入Oseen曳力公式和非齐次项 ,建立了振荡条件下颗粒完整的运动微分方程 ,并对其运动轨迹进行了数值模拟 .从理论上证实了颗粒在EDB中存在稳定的阻尼振... 详细信息

改进了davis关于微米单颗粒在EDB(electrodynamicbalance)中悬浮的两区理论 ,通过引入Oseen曳力公式和非齐次项 ,建立了振荡条件下颗粒完整的运动微分方程 ,并对其运动轨迹进行了数值模拟 .从理论上证实了颗粒在EDB中存在稳定的阻尼振荡过渡区 ,给出了不同于davis理论的三区状态图 (δ β图 ) ,从而构建了振荡条件下颗粒EDB研究的理论基础 .这些理论结果的可靠性通过实验也得到了很好的验证 .

关键词： EDB 微米单颗粒振荡特性运动轨迹数值模拟

Improved Analytical Methods for Determination of Residues of Nitrapyrin and 6-Chloropicolinic Acid in Different Crop Matrices by Liquid Chromatography-Tandem Mass Spectrometry

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journal of Agricultural Chemistry and Environment 2024年第3期13卷 263-281页

作者： Fabiola G. Zuno-Floriano Riza L. Reyes-Punongbayan Matt j. Hengel Department of Environmental Toxicology University of California Davis California USA

Novel analytical methods were developed for the determination of nitrapyrin and 6-chloropicolinic acid (6-CPA) residues in agricultural products. Nitrapyrin was extracted with hexane: toluene (1:1, v/v) and 6-CPA with 0.1 N sodium hydroxide (NaOH). For nitrapyrin, samples were cleaned with silica solid phase extraction (SPE) and for 6-CPA with C18 or carbon SPE. Analysis was performed by liquid chromatography-tandem mass spectroscopy (LC-MS/MS) with external calibration (0.010 to 0.0010 µg∙mL−1 for nitrapyrin and 0.0050 to 0.00025 µg∙mL−1 for 6-CPA). Recoveries for nitrapyrin and 6-CPA were 68% - 102% and 66% - 90%, respectively. Nitrapyrin was detected in celery and onion (−1) and 6-CPA in onion, mustard greens and lettuce (−1). Lower level method validation (LLMV) for nitrapyrin and 6-CPA was 0.020 µg∙g−1 and 0.050 µg∙g−1, respectively. The methods presented in this study are robust and were utilized for the registration of nitrapyrin on agricultural commodities in the United States.

关键词： Herbicide Agricultural Products External Calibration LC-MS/MS Registration