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Anion structural effects on interaction of rare earth element ions with Dowex 50W X8 cation exchange resin

Journal of Rare Earths 2018年第8期36卷 879-890页

作者： Duane D.Miller Ranjani Siriwardane dustin Mcintyre U.S. Department of Energy National Energy Technology Laboratory AECOM

The effect of the anion in the original rare earth element（REE） solution on the reversible ion exchange of Ce nitrate and Ce sulfate with the Dowex 50 W X8 was investigated using attenuated total reflection infrared（ATR-IR） spectroscopy, continuous flow reactor studies coupled with inductively coupled plasma mass spectroscopy（ICp-MS）, and density functional theory（DFT）. The simulated IR spectrum at the DFT B3 LYp/6-31 G（d） level was compared to the experimental results to characterize the IR spectrum, molecular interactions, and bonding of the ion exchanged species. The continuous liquid flow reactor studies show a capacity of 0.72 mmol/g sorbent for the Ce nitrateand 0.96 mmol/g sorbent for the Ce sulfate with the Dowex 50 W X8. The flow reactor studies reveal the type of solute anion（SO_4^（（2-）） or NO_3^（（-））） associated with the REE during cation exchange significantly affects the sorption capacity of the Dowex 50 W X8 ion exchange resin. The calculated REE binding energy（BE） and the DFT optimized structures suggest that the differences in sorption capacity is the result of the formation of different types of partially ionexchanged Ce_2^（（3＋））2 SO_4^（（2-）） and Ce^（（3＋）） 3 NO_3^（（-））. These results suggest that the solute anion affects the equilibrium constants of the Dowex resin by the formation of a charged layer capable of retaining the counterion. Modifying the sulfonic acid site（H＋） in the Dowex 50 W X8 with the NH_4~＋ counterion does not affect the sorption capacity and retention times of the Ce nitrate and Ce sulfate species. These results suggest that the counterions and co-ions having a finite size, may limit access to the Dowex sulfonate active site where the type of REE cation as a nitrate or sulfate in solution may significantly modify the sorption capacity of the ion exchange resin. Similar results are obtained during sorption with nitrates and sulfates of Sm and Yb.

关键词： Ion exchange Dowex Anion effects Rare earth metal sorption

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Rate analysis of sorption of Ce^3＋,Sm^3＋,and Yb^3＋ions from aqueous solution using Dowex 50W-X8 as a sorbent in a continuous flow reactor

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Journal of Rare Earths 2018年第6期36卷 648-655页

作者： Esmail Monazam Ranjani Siriwardane Duane Miller dustin Mclntyre REM Engineering Services PLLC3537 Collins Ferry Rd.MorgantownWV 26505USA National Energy Technology Laboratory U.S.Department of Energy3610 Collins Ferry Rd.MorgantownWV26507-0880USA AECOM 3610 Collins Ferry Rd.E O.Box 880MorgantownWV 26507-0880USA

Kinetic analysis of removal of three rare earth elements metals, Ce, Sm, and Ybions from aqueous solutions in a continuous flow fixed bed reactor using Dowex 50 W-X8 ion-exchange resin was conducted. The performance of the fixed bed sorption was evaluated using the concept of the sorption breakthrough process. parameters characteristic of a fixed bed sorption such as breakthrough times,saturation times, critical reactor lengths, and lengths of mass transfer zone were inferred from the metal ion concentration breakthrough curves. The sorption capacity of Dowex 50 W-X8 ion-exchange resin for Ce3+, Sm3+, and Yb3+ are 191, 252, and 294 mg/g, respectively. The sorption kinetics were evaluated using a zero-order, first-order and second-order reaction models. The kinetics of the sorption process follows a zero-order model which has not been reported before. The rate constants of sorption using the zero-order kinetic model are obtained. Two different analysis were conducted to identify whether the diffusion is intraparticle or film diffusion. Both analysis confirms that the film diffusion is the controlling mechanism in reactor bed.

关键词： Rare earth metal ion removal Sorption of rare earths Dowex 50W-X8 for rare earth ion-exchange

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Diagenetic signatures in the deltaic and fluvial-estuarine Messinian sandstone reservoirs in the Nile Delta as a tool for high-resolution stratigraphic correlations

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International Journal of Sediment Research 2023年第5期38卷 754-768页

作者： Mahmoud Leila Andrea Moscariello dustin Sweet Branimir ?egvi? Geology Department Faculty of Science Mansoura University Department of Earth Sciences University of Geneva Department of Geosciences Texas Tech University

The current study utilizes a range of diagenetic fingerprints to differentiate between sandstone facies deposited in the Nile Delta before and during the Messinian salinity crisis(MSC), which is normally a challenging task considering the complex bio-and lithostratigraphic subdivisions of Messinian rock units. Subaerial exposure of the pre-MSC(Qawasim deltaic sandstone), during drawdown of the Mediterranean Sea at the time of the MSC, triggered pervasive dissolution of unstable rock fragments, kaolinization of feldspar, and meteoric dolomitization of carbonate. This was followed by mesogenetic calcite cementation and kaolinite transformation into dickite in deeply buried Qawasim sandstone. Comparatively, the Abu Madi estuarine facies, deposited during transgression after drawdown related to the MSC,is characterized by eogenetic iron(Fe)-calcite, glauconite, and pyrite(averages of 14.5%, 6%, and 2%,respectively). This facies transition is marked by abundance of mature glauconite(with potassium oxide(K2O) at about 8%) whose content abates upward from the transgression surface. Moreover, the compositional variability of the Abu Madi sandstone gave rise to multiple diagenetic trajectories that resulted in chlorite formation presumably following smectite and kaolinite. Listed diagenetic variations in the studied Messinian sandstone resulted from a complex interplay between rocks’ compositional,depositional, and burial attributes, ultimately serving as a basis for high-resolution stratigraphic correlation in continental and marginal marine settings with poor biostratigraphic controls.

关键词： Messinian Nile Delta Diagenesis Deltaic sedimentation Fluvial-estuarine Stratigraphic correlation

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Automated software testing : :introduction, management, and performance /

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丛书名：软件工程实践丛书

2003年

作者： dustin Elfriede

来源：畅想之星图书光盘版（南... 评论

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Image guided percutaneous gastrostomy catheter placement: How we do it safely and efficiently

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World Journal of Gastroenterology 2020年第4期26卷 383-392页

作者： Sasan partovi Xin Li Eunice Moon dustin Thompson Section of Interventional Radiology Imaging Institute Cleveland Clinic Foundation

Gastrostomy tube is an effective and safe long-term feeding access that is welltolerated by *** typical placement routes include surgical,endoscopic and interventional radiologic *** particular,percutaneous interventional radiologic gastrostomy(pIRG)has increasingly become the preferred method of choice in many *** many pIRG techniques have been developed since the 1980s,there is still a paucity of evidence supporting the choice of a most-optimal pIRG ***,there is a large variation in institutional approach to *** are a large,quaternary academic institution with an extensive experience in ***,we aim to present the“push”pIRG technique utilized in our institution,to review the current literature,to discuss the optimal choice of pIRG technique and to generate further interests in comparison studies.

关键词： percutaneous interventional radiologic gastrostomy Institutional approach push technique

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Role of hepatocyte nuclear factor 4-alpha in gastrointestinal and liver diseases

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World Journal of Gastroenterology 2019年第30期25卷 4074-4091页

作者： Matthew M Yeh dustin E Bosch Sayed S Daoud Department of pathology University of Washington School of MedicineSeattleWA 98195United States Department of Medicine University of Washington School of MedicineSeattleWA 98195United States Department of pharmaceutical Sciences Washington State University Health SciencesSpokaneWA 99210United States

Hepatocyte nuclear factor 4-alpha(HNF4α)is a highly conserved member of nuclear receptor superfamily of ligand-dependent transcription factors that is expressed in liver and gastrointestinal organs(pancreas,stomach,and intestine).In liver,HNF4αis best known for its role as a master regulator of liver-specific gene expression and essential for adult and fetal liver *** of HNF4αexpression has been associated with many human diseases such as ulcerative colitis,colon cancer,maturity-onset diabetes of the young,liver cirrhosis,and hepatocellular ***,the precise role of HNF4αin the etiology of these human pathogenesis is not well *** information is known about the role of HNF4αisoforms in liver and gastrointestinal disease *** is,therefore,a critical need to know how disruption of the expression of these isoforms may impact on disease progression and *** this review,we will update our current understanding on the role of HNF4αin human liver and gastrointestinal *** further provide additional information on possible use of HNF4αas a target for potential therapeutic approaches.

关键词： Hepatocyte nuclear factor 4-alpha Liver cirrhosis Hepatocellular carcinoma Viral hepatitis Gastrointestinal tract Colorectal carcinoma Transcription factor

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Complex courtship success and plasticity environments displays facilitate in signaling across male reproductive variable

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Current Zoology 2011年第2期57卷 175-186页

作者： dustin J. WILGERS Eileen A. HEBETS School of Biological Sciences University of Nebraska-Lincoln Lincoln NE USA

Effective signal transmission is essential for communication. In environments where signal transmission is highly variable, signalers may utilize complex signals, which incorporate multiple components and modalities, to maintain effective communication. Male Rabidosa rabida wolf spiders produce complex courtship signals, consisting of both visual and seismic components. We test the hypothesis that the complex signaling of R. rabida contributes to male reproductive success in variable signaling environments. We first examine the condition-dependence of foreleg ornamentation （a presumed visual signal） and seismic signal components and find that both may provide potentially redundant information on foraging history. Next, we assessed reproductive success across manipulated signaling environments that varied in the effectiveness of visual and/or seismic signal transmission. In environments where only one signal could be successfully transmitted （e.g., visual or seismic）, pairs were still able to successfully copulate. Additionally, we found that males altered their courtship display depending on the current signaling environment. Specifically, males reduced their use of a visual display component in signaling environments where visual signal transmission was ablated. Incorporating signals in multiple modalities not only enables R. rabida males to maintain copulation success across variable signaling environments, but it also enables males to adjust their composite courtship display to current signaling conditions .

关键词： Communication Multimodal Signal evolution Condition-dependent Lycosidae Rabidosa rabida Efficacy back-up Redundant signals

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An efficient geosciences workflow on multi-core processors and GpUs:a case study for aerosol optical depth retrieval from MODIS satellite data

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International Journal of Digital Earth 2016年第8期9卷 748-765页

作者： Jia Liu dustin Feld Yong Xue Jochen Garcke Thomas Soddemann peiyuan pan Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingChina Faculty of Life Sciences and Computing London Metropolitan UniversityLondonUK Fraunhofer Institute for Algorithms and Scientific Computing SCAI Sankt AugustinGermany Institute for Numerical Simulation University of BonnBonnGermany University of Chinese Academy of Sciences BeijingChina Department of Computer Science University of CologneCologneGermany

Quantitative remote sensing retrieval algorithms help understanding the dynamic aspects of Digital ***,the Big Data and complex models in Digital Earth pose grand challenges for computation *** this article,taking the aerosol optical depth(AOD)retrieval as a study case,we exploit parallel computing methods for high efficient geophysical parameter *** present an efficient geocomputation workflow for the AOD calculation from the Moderate Resolution Imaging Spectroradiometer(MODIS)satellite *** to their individual potential for parallelization,several procedures were adapted and implemented for a successful parallel execution on multicore processors and Graphics processing Units(GpUs).The benchmarks in this paper validate the high parallel performance of the retrieval workflow with speedups of up to 5.x on a multi-core processor with 8 threads and 43.x on a *** specifically address the time-consuming model retrieval part,hybrid parallel patterns which combine the multicore processor’s and the GpU’s compute power were implemented with static and dynamic workload distributions and evaluated on two systems with different CpU–GpU *** is shown that only the dynamic hybrid implementation leads to a greatly enhanced overall exploitation of the heterogeneous hardware environment in varying circumstances.

关键词： Digital earth highperformance computing GpU multi-core hybrid parallel pattern aerosol optical depth retrieval workflow

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Ocean stratification and sea-ice cover in Barents and Kara seas modulate sea-air methane flux:satellite data

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Advances in polar Science 2021年第2期32卷 118-140页

作者： Leonid YURGANOV dustin CARROLL Andrey pNYUSHKOV Igor pOLYAKOV Hong ZHANG University of Maryland Baltimore County(ret) BaltimoreMDUSA Moss Landing Marine Laboratories San JoséState UniversityCAUSA International Arctic Research Center University of Alaska FairbanksAKUSA Jet propulsion Laboratory California Institute of TechnologyCAUSA

The diverse range of mechanisms driving the Arctic amplification and global climate are not completely understood and,in particular,the role of the greenhouse gas methane(CH4)in the Arctic warming remains *** sources of methane at the ocean seabed in the Barents Sea and other polar regions are well ***,some of those publications suggest that negligible amounts of methane fluxed from the seabed enter the atmosphere,with roughly 90%of the methane consumed by *** in situ observations are taken during summer,which is favorable for collecting data but also characterized by a stratified water *** present perennial observations of three Thermal IR space-borne spectrometers in the Arctic between 2002 and *** to estimates derived from the data synthesis ECCO(Estimating the Circulation and Climate of the Ocean),in the ice-free Barents Sea the stratification in winter weakens after the summer strong *** convection,storms,and turbulent diffusion mix the full-depth water ***4 excess over a control area in North Atlantic,measured by three sounders,and the oceanic Mixed Layer Depth(MLD)both maximize in winter.A significant seasonal increase of sea-air exchange in ice-free seas is *** amplitude of the seasonal methane cycle for the Kara Sea significantly increased since the beginning of the *** may be explained by a decline of ice concentration *** annual CH4 emission from the Arctic seas is estimated as 2/3 of land *** Barents/Kara seas contribute between 1/3 and 1/2 into the Arctic seas annual emission.

关键词： satellite data greenhouse gases methane Thermal IR(TIR) Arctic

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Effect of age on aortic atherosclerosis

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Journal of Geriatric Cardiology 2013年第2期10卷 135-140页

作者： Michael A. Chen Miwa Kawakubo patrick M. Colletti Dongxiang Xu Laurie LaBree dustin Robert Detrano Stanley p Azen Nathan D. Wong Xue-Qiao Zhao Department of Medicine Division of Cardiology Harborview Medical Center/University of Washington 325 9th Avenue Box 359748 Seattle WA 98104 USA Department of preventive Medicine Division of Biostatistics Keck School of Medicine of the University of Southern California 2001 N Soto Street SSB 201A M/C 9234 Los Angeles CA 90089-9237 USA Department of Radiology Keck School of Medicine of the University of Southern California1 1500 San Pablo Street Second Floor Imaging Los Angeles CA 90033 USA Department of Radiology University of Washington School of Medicine Box 357115 1959 Pacific Street RR-215 Seattle WA 98195-7117 USA Department of Radiological Sciences University of California Irvine School of Medicine 101 the City Drive South Route 140 Orange CA 92868 USA Department of Medicine UC Irvine School of Medicine 333 City Blvd. West Suite 400 Orange CA 92868-3298 USA

Objective To examine the association of atherosclerosis burden in the survivors of an asymptomatic elderly cohort study and its relationship to other coronary risk factors (specifically, age) by evaluating aortic atherosclerotic wall burden by magnetic resonance imaging (MRI). Methods A total of 312 participants in an ongoing observational cohort study underwent cardiac and descending thoracic aorta imaging by MRI. Maximum wall thickness was measured and the mean wall thickness ***/outer wall ratio was used as a normalized wall index (NWI) adjusted for artery size difference among participants. percent wall volume (pWV) was calculated as NWI ×*** In this asymptomatic cohort (mean age: 76 years), the mean (SD) aortic wall area andwall thicknesswere 222 ±45 mm2 and 2.7 ±0.4 mm, respectively. Maximum wall thickness was 3.4 ±0.6 mm, and pWV was 32% ±4%. Women appeared to have smaller wall area,but after correcting for their smaller artery size, had significantly higher pWV than men (p = 0.03). Older age was associatedwith larger wall area (p = 0.04 for trend) with similar pWVs. However, there were no statistically significant associations between standard risk factors,Framingham global risk, or metabolic syndrome status, therapy for cholesterol or hypertension, coronary or aortic calcium score, and the aortic wall burden. Aortic calcificationwas associated with coronary calcification. Conclusions Asymptomatic elderly in this cohort had a greater descending thoracic aortic wall volume that correlated with age, andwomen had a significantly increased pWV compared to men. In these survivors, the atherosclerotic aortic wall burden was not significantly associated with traditional risk factors or with coronary or aortic calcium scores or coronary calcium progression. Results suggest that age, or as yet unidentified risk factor(s), may be responsible for the increase in atherosclerosis.

关键词： Aging Aortic atherosclerosis Atherosclerotic risk factors Magnetic resonance imaging

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