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Environmental levels and toxicological potencies of a novel mixed halogenated carbazole

Emerging Contaminants 2016年第3期2卷 166-172页

作者： Miren Pena-Abaurrea Matthew Robson Sri Chaudhuri Nicole Riddell Robert McCrindle Brock Chittim Robert Parette Un-Ho Jin Stephen Safe David Poirier Ralph Ruffolo richard dyer Rachael Fletcher Paul A..Helm Eric J.Reiner Department of Analysis CEPSA Research CenterAlcala de Henares28805Spain Department of Chemistry University of TorontoTorontoONM5S 3H6Canada Ontario Ministry of the Environment and Climate Change TorontoONM9P 3V6Canada Conservation Ontario NewmarketONL3Y 2P5Canada Department of Chemistry Brock UniversitySt.CatharinesONL2S 3A1Canada Wellington Laboratories Inc. GuelphONN1G 3M5Canada Department of Chemistry University of GuelphGuelphONN1G 2W1Canada Matson&Associates Inc.State CollegePA16801USA Veterinary Medicine&Biomedical Sciences Texas A&M UniversityTexasTX77843e4461USA Ministry of Northern Development and Mines SudburyONP3E 6B5Canada School of the Environment University of TorontoONM5S 3EBCanada

The present work involves an extensive analytical and toxicological description of a recently identified mixed halogenated carbazole found in sediment samples,1,8-dibromo-3,6-dichloro-9H-carbazole(BCCZ).Concentrations and the relative effect potency(REP)were calculated for the target BCCZ in a set of stream sediments collected in 2008 in Ontario,*** levels calculated for BCCZ as compared to those previously assessed for legacy persistent organic pollutants(POPs)in the same samples revealed a significant contribution of BCCZ to the total organic chemical contamination(<1%e95%;average 37%).The corresponding dioxin toxic equivalencies(TEQs)of BCCZ in the sediment extracts were estimated from experimental REP *** experimental data presented supports the classification of this emerging halogenated chemical as a contaminant of emerging environmental *** potential emission sources could not be identified,this study highlights the importance of on-going research for complete characterization of halogenated carbazoles and related compounds.

关键词： Halogenated carbazoles Levels GC×GC REP TEQ Dioxin-like Risk assessment Regulation

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Trace-Level Analysis of Hexavalent Chromium in Lake Sediment Samples Using Ion Chromatography Tandem Mass Spectrometry

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Journal of Environmental Protection 2016年第3期7卷 422-434页

作者： Stefanie Mädler Fengrong Sun Cindy Tat Nadya Sudakova Peter Drouin Robert J. Tooley Eric J. Reiner Teresa A. Switzer richard dyer H. M. Skip Kingston Matt Pamuku Vasile I. Furdui Laboratory Services Branch Ontario Ministry of the Environment and Climate Change Ontario Canada Conservation Ontario Ontario Canada Department of Chemistry University of Toronto Ontario Canada Ontario Geological Survey Ontario Ministry of Northern Development and Mines Ontario Canada Department of Chemistry and Biochemistry Duquesne University Pittsburgh USA Applied Isotope Technologies Pittsburgh USA

The analysis of hexavalent chromium, Cr(VI), in soil and sediment samples has been predominantly carried out in materials containing elevated levels. Reliable analysis of trace-level of Cr(VI) in sediment samples remains challenging. Cr(VI) analyses with multipoint calibration and speciated isotope dilution (SID) adapted from U.S. EPA method 6800 were used to measure lower-level Cr(VI) on an ion chromatograph coupled with a tandem mass spectrometer (IC-MS/MS). Lake sediment samples were collected from various locations in Northern Ontario and Cr(VI) was extracted using both alkaline digestion and ethylene diaminetetraacetic acid (EDTA) extraction. Certified reference materials were extracted and analyzed by IC-MS/MS and UV-VIS detection. The SID-MS approach allowed for the quantification of Cr(VI) in samples with concentration levels below 0.5 μg.g-1 wet weight.

关键词： Trace-Level Analysis Ion Chromatography Tandem Mass Spectrometry Chromium Speciation Speciated Isotope Dilution

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Contribution of national bioassessment approaches for assessing ecological water security： an AUSRIVAS case study

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Frontiers of Environmental Science & Engineering 2013年第5期7卷 669-687页

作者： Susan J. NICHOLS Fiona J. dyer Institute for Applied Ecology and MDBfutures CRN University of Canberra Canberra ACT 2601 Australia

River managers in Australia are managing in the face of extremes to provide security of water supply for people, production and the environment. Balancing the water requirements of people, environments and econo- mies requires that water security is viewed holistically, not just in terms of the water available for human consump- tion. Common definitions of water security focus on the needs of both humans and ecosystems for purposes such as drinking, agriculture and industrial use, and to maintain ecological values. Information about achieving water security for the environment or ecological purposes can be a challenge to interpret because the watering require- ments of key ecological processes or assets are not well understood, and the links between ecological and human values are often not obvious to water users. Yet the concepts surrounding river health are inherently linked to holistic concepts of water security. The measurement of aquatic biota provides a valuable tool for managers to understand progress toward achieving ecological water security objectives. This paper provides a comprehensive review of the reference condition approach to river health assessment, using the development of the Australian River Assessment System （AUSRIVAS） as a case study. We make the link between the biological assessment of river health and assessment of ecological water security, and suggest that such an approach provides a way of reporting that is relevant to the contribution made by ecosystems to water security. The reference condition approach, which is the condition representative of minimally disturbed sites organized by selected physical, chemical, and biological characteristics, is most important for assessing ecological water security objectives.

关键词： ecological water security biological assessment river health

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Modeling of fiber bridging in fluid flow for well stimulation applications

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Petroleum Science 2020年第3期17卷 671-686页

作者： Mehdi Ghommem Mustapha Abbad Gallyam Aidagulov Steve dyer Dominic Brady Department of Mechanical Engineering American University of ShaijahSharjah 26666United Arab Emirates Schlumberger Dhahran Carbonate Research Center Dammam/Doha Camp 31942Kingdom of Saudi Arabia Schlumberger Completions RosharonTX 77583USA

Accurate acid placement constitutes a major concern in matrix stimulation because the acid tends to penetrate the zones of least resistance while leaving the low-permeability regions of the formation *** materials(fibers and solid particles)have recently shown a good capability as fluid diversion to overcome the issues related to matrix *** the success achieved in the recent acid stimulation jobs stemming from the use of some products that rely on fiber flocculation as the main diverting mechanism,it was observed that the volume of the base fluid and the loading of the particles are not *** current industry lacks a scientific design guideline because the used methodology is based on experience or empirical studies in a particular area with a particular *** is important then to understand the fundamentals of how acid diversion works in carbonates with different diverting mechanisms and *** modeling and computer simulations are effective tools to develop this understanding and are efficiently applied to new product development,new applications of existing products or usage *** this work,we develop a numerical model to study fiber dynamics in fluid *** employ a discrete element method in which the fibers are represented by multi-rigid-body systems of interconnected *** discrete fiber model is coupled with a fluid flow solver to account for the inherent simultaneous *** focus of the study is on the tendency for fibers to flocculate and bridge when interacting with suspending fluids and encountering restrictions that can be representative of fractures or wormholes in *** trends of the dynamic fiber behavior under various operating conditions including fiber loading,flow rate and fluid viscosity obtained from the numerical model show consistency with experimental *** present numerical investigation reveals that the bridging capability of the fi

关键词： Fiber bridging Fiber flocculation Modeling and numerical simulation Discrete element method Fiber-fluid coupling Sensitivity analysis

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Rheological properties of rare earth minerals flotation pulp in the presence of anions

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Journal of Rare Earths 2024年第11期42卷 2172-2182,I0007页

作者： Moonchul Jung Bogale Tadesse Craig Dick Alex Logan Laurence dyer Boris Albijanic Western Australia School of Mines Curtin UniversityKalgoorlieWA 6430Australia Lynas Rare Earths Ltd Mt Weld Elora RoadLavertonWA 6440Australia

Water quality has been found to significantly influence the flotation operations due to the alteration of surface properties of *** effect of cations on the flotation of RE minerals has been studied,however,there are still very limited information regarding the effect of *** present study examined the impact of specific anions such as Cl^(-),SO_(4)^(2-),and HCO_(3)^(-)on the flotation performance of rare earth(RE) *** study integrates flotation experiments,rheology measurements,entrainment experiments,zeta potential measurements and settling *** is observed that an increase in the concentration of these anions lead to a decrease in the recovery of RE minerals and an increase in the recovery of FeO minerals and thus negatively affecting flotation *** adverse effect is most pronounced with Cl^(-)and least noticeable with HCO_(3)^(-).An increase in the non-selective entrainment of gangue minerals is observed when the flotation pulp has higher *** reduction in the zeta potential of fine particles in the presence of these results in a higher pulp viscosity due to increased attractive forces between *** findings were verified by settling experiments and calculations based on the DLVO theory.

关键词： Flotation Rare earth ore Anions Pulp rheology Entrainment DLVO theory

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Increased number of symptoms during the acute phase of SARS-CoV-2 infection in athletes is associated with prolonged time to return to full sports performance—AWAREⅧ

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Journal of Sport and Health Science 2024年第3期13卷 280-287,I0001页

作者： Carolette Snyders Marlise dyer Nicola Sewry Esme Jordaan Martin Schwellnus Sport Exercise Medicine and Lifestyle Institute(SEMLI)Faculty of Health SciencesUniversity of PretoriaPretoria 0083South Africa Section Sports Medicine Faculty of Health SciencesUniversity of PretoriaPretoria 0083South Africa IOC Research Centre of South Africa Pretoria 0083South Africa Biostatistics Unit South African Medical Research CouncilTygerberg 7505South Africa Statistics and Population Studies Department University of the Western CapeCape Town 7535South Africa

Purpose The aim of the study was to identify factors associated with prolonged time to return to full performance(RTFP)in athletes with recent severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)*** Prospective cohort study with cross sectional analysis.A total of 84 athletes with confirmed SARS-CoV-2 infection assessed at a coronavirus disease 2019 recovery clinic gave a history of age,sex,type/level of sport,co-morbidities,pre-infection training hours,and 26 acute SARS-CoV-2 symptoms from 3 categories(“nose and throat”,“chest and neck”,and“whole body”/systemic).Data on days to RTFP were obtained by structured *** associated with RTFP were demographics,sport participation,history of co-morbidities,pre-infection training history,and acute symptoms(type,number).Outcomes were:(a)days to RTFP(median,interquartile range(IQR))in asymptomatic(n=7)and symptomatic athletes(n=77),and(b)hazard ratios(HRs;95%confidence interval)for symptomatic athletes with *** a factor(univariate,multiple models).HR0.05).Factors associated with prolonged RTFP(univariate models)were:females(HR=0.57;p=0.014),endurance athletes(HR=0.41;p<0.0001),co-morbidity number(HR=0.75;p=0.001),and respiratory disease history(HR=0.54;p=0.026).In symptomatic athletes,prolonged RTFP(multiple models)was significantly associated with increased“chest and neck”(HR=0.85;p=0.017)and“nose and throat”(HR=0.84;p=0.013)symptoms,but the association was more profound between prolonged RFTP and increased total number of“all symptoms”(HR=0.91;p=0.001)and“whole body”/systemic(HR=0.82;p=0.007)*** A larger number of total symptoms and specifically“whole body”/systemic symptoms during the acute phase of SARS-CoV-2 infection in athletes is associated with prolonged RTFP.

关键词： Athletes COVID-19 Performance Recovery Return to play

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Patterns of reproductive isolation in the Drosophila subquinaria complex： can reinforced premating isolation cascade to other species？

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Current Zoology 2016年第2期62卷 183-191页

作者： Devon P. HUMPHREYS Howard D. RUNDLE Kelly A. dyer Department of Genetics University of Georgia Athens GA 30602 USA Department of Biology University of Ottawa Ottawa ON K1N 6N5 Canada

The reinforcement of premating barriers due to reduced hybrid fitness in sympatry may cause secondary sexual isolation within a species as a by-product. Consistent with this, in the fly Drosophila subquinaria, females that are sympatric with D. recens mate at very low rates not only with D. recens, but also with conspecific D. subquinaria males from allopatry. Here, we ask if these effects of re- inforcement cascade more broadly to affect sexual isolation with other closely related species. We assay reproductive isolation of these species with D. transversa and find that choosy D. subquinaria females from the region sympatric with D. recens discriminate strongly against male D. transversa, whereas D. subquinaria from the allopatric region do not. This increased sexual isolation cannot be explained by natural selection to avoid mating with this species, as they are allopatric in geographic range and we do not identify any intrinsic postzygotic isolation between D. subquinaria and D. transversa. Variation in epicuticular hydrocarbons, which are used as mating signals in D. subquinaria, follow patterns of premating isolation： D. transversa and allopatric D. subquinaria are most similar to each other and differ from sympatric D. subquinaria, and those of D. recens are distinct from the other two species. We suggest that the secondary effects of reinforcement may cascade to strengthen reproductive isolation with other species that were not a target of selection. These effects may enhance the divergence that occurs in allopatry to help explain why some species are already sexually isolated upon secondary contact.

关键词： epicuticular hydrocarbons hybrid sterility mate choice reinforcement speciation Wolbachia

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Psychophysics of the hoverfly: categorical or continuous color discrimination?

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Current Zoology 2019年第4期65卷 483-492页

作者： Lea Hannah Adrian G. dyer Jair E. Garcia Alan Dorin Martin Burd School of Biological Sciences Monash University Clayton Victoria 3800 Australia Hawkesbury Institute for the Environment Western Sydney University Richmond New South Wales 2753 Australia School of Media and Communication RMIT University Melbourne Victoria 3001 Australia Department of Physiology Monash University Clayton Victoria 3800 Australia Faculty of Information Technology Monash University Clayton Victoria 3800 Australia

There is increasing interest in flies as potentially important pollinators. Flies are known to have a complex visual system, in eluding 4 spectral classes of photoreceptors that con tribute to the perception of color. Our current understanding of how color signals are perceived by flies is based on data for the blowfly Lucilia sp., which after being conditi oned to rewarded mono chromatic light stimuli, showed evidenee of a categorical color visual system. The resulting opponent fly color space has 4 distinct categories, and has been used to interpret how some fly pollinators may perceive flower colors. However, formal proof that flower flies (Syrphidae) only use a simple, categorical color process remains outstanding. In free-flying experiments, we tested the hoverfly Eristalis tenax, a Batesian mimic of the honeybee, that receives its nutrition by visiting flowers. Using a range of broadband similar-dissimilar color stimuli previously used to test color perception in pollinating hymenopteran species, we evaluated if there are steep changes in behavioral choices with continuously increasing color differences as might be expected by categorical color processing. Our data revealed that color choices by the hoverfly are mediated by a continuous monotonic function. Thus, these flies did not use a categorical processing, but showed evidenee of a color discrimination function similar to that observed in several bee species. We therefore empirically provide data for the minimum color distanee that can be discriminated by hoverflies in fly color space, enabling an improved un derstandi ng of plant-poll in ator interactions with a non-model insect species.

关键词： chromatic signal color model floral color fly pollination plant-pollinator vision

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Association of Adolescent Bullying Victimization with Meeting 24-hour Movement Behavior Recommendations:A Cross-Sectional Study Using the Combined 2015-2019 Youth Risk Behavior Survey

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Journal of Science in Sport and Exercise 2023年第2期5卷 182-190页

作者： You Fu Ryan DBurns Peng Zhang Samantha dyer Nora Constantino School of Public Health University of NevadaRenoNVUSA Department of Health&Kinesiology University of UtahSalt Lake CityUTUSA Physical Education Teacher Education Department East Stroudsburg UniversityEast StroudsburgPAUSA

Purpose To examine the association between bullying victimization and meeting recommendations for the 24-h movement behaviors of physical activity,screen use,and sleep in *** Participants were a sample of US adolescents from the 2015–2019 national Youth Risk Behavior Survey(N=43,847;Mean age=16.0±1.2 years;50.7%female).The bullying victimization variables included the bullying expe-riences at school and *** multivariable logistic regressions analyzed associations between bullying victimiza-tion and meeting recommendations for 24-h movement behaviors controlling for age,sex,race/ethnicity,and weight *** Adolescents meeting non-academic screen and sleep recommendations had 25%(OR=0.75,95%CI 0.69–0.82)and 19%(OR=0.81,95%CI 0.74–0.89)lower odds to be bullied at *** meeting non-academic screen recommen-dation had 27%lower odds(OR=0.73,95%CI 0.58–0.91)of experience online *** adolescents who met physical activity,non-academic screen use,and sleep recommendations had lower odds of experience the bullying at school of 29%(OR=0.71,95%CI 0.59–0.85),26%(OR=0.74,95%CI 0.61–0.90),and 31%(OR=0.69,95%CI 0.55–0.86),*** the females,non-academic screen use was the only movement behavior yielded statistical significance,in that those who met the recommendation had 15%(OR=0.85,95%CI 0.73–0.98)lower odds of experience the bullying at *** The presence of meeting 24-h movement behavior recommendations associates with a lower probability of bullying at school and online in ***,these associations tended to be stronger and more consistent in males compared to females.

关键词： School bullying Cyber bullying Youth Behavior

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Element selection for functional materials discovery by integrated machine learning of elemental contributions to properties

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npj Computational Materials 2023年第1期9卷 639-648页

作者： Andrij Vasylenko Dmytro Antypov Vladimir V.Gusev Michael W.Gaultois Matthew S.dyer Matthew J.Rosseinsky Department of Chemistry University of LiverpoolCrown StreetLiverpool L697ZDUnited Kingdom Department of Computer Science University of LiverpoolAshton StreetLiverpool L693BXUnited Kingdom

The unique nature of constituent chemical elements gives rise to fundamental differences in *** materials based on their phase fields,defined as sets of constituent elements,before specific differences emerge due to composition and structure can reduce combinatorial complexity and accelerate screening,exploiting the distinction from composition-level *** and evaluation of novelty of materials classes align with the experimental challenge of identifying new areas of *** address this,we present PhaseSelect,an end-to-end machine learning model that combines representation,classification,regression and novelty ranking of phase *** leverages elemental characteristics derived from computational and experimental materials data and employs attention mechanisms to reflect the individual element contributions when evaluating functional performance of phase *** demonstrate this approach for high-temperature superconductivity,high-temperature magnetism,and targeted bandgap energy applications,showcasing its versatility and potential for accelerating materials exploration.

关键词： materials phase elements

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