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Analysis of PFAAs in American alligators part 1： Concentrations in alligators harvested for consumption during South Carolina public hunts

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journal of Environmental Sciences 2017年第11期29卷 24-30页

作者： jessica j.Tipton Louis j.Guillette jr Susan Lovelace Benjamin B.Parrott thomas R.Rainwater jessica L.Reiner College of Charleston Charleston SC 29424 USA Medical University of South Carolina Department of Obstetrics and Gynecology Charleston SC 29425 USA University of Georgia Odum School of Ecology Savannah River Ecology Laboratory Jackson SC 29831 USA Tom Yawkey Wildlife Center & Belle W. Baruch Institute of Coastal Ecology and Forest Science Clemson University P.O. Box 596 Georgetown SC 29442 USA National Institute of Standards and Technology Chemical Sciences Division Hollings Marine Laboratory Charleston SC 29412 USA

Environmental contamination resulting from the production or release of harmful chemicals can lead to negative consequences for wildlife and human health. Perfluorinated alkyl acids（PFAAs） were historically produced as protective coatings for many household items and currently persist in the environment, wildlife, and humans. PFAAs have been linked to immune suppression, endocrine disruption, and developmental toxicity in wildlife and laboratory studies. This study examines the American alligator, Alligator mississippiensis,as an important indicator of ecosystem contamination and a potential pathway for PFAA exposure in humans. Alligator meat harvested in the 2015 South Carolina（SC） public hunt season and prepared for human consumption was collected and analyzed for PFAAs to determine meat concentrations and relationships with animal body size（total length）, sex, and location of harvest. Of the 15 PFAAs analyzed, perfluorooctane sulfonate（PFOS） was found in all alligator meat samples and at the highest concentrations（median 6.73 ng/g）. No relationship was found between PFAA concentrations and total length or *** of one or all compounds varied significantly across sampling locations, with alligators harvested in the Middle Coastal hunt unit having the highest PFOS concentrations（median 16.0 ng/g; p = 0.0001）. Alligators harvested specifically from Berkley County, SC（located in the Middle Coastal hunt unit） had the highest PFOS concentrations and the greatest number of PFAAs detected（p 〈 0.0001）. The site-specific nature of PFAA concentrations in alligator meat observed in this study suggests a source of PFAA contamination in Berkley County, SC.

关键词： Perfluorinated alkyl acids American alligators South Carolina Perfluorooctane sulfonate(PFOS) Dietary exposure

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Force microscopy of the Caenorhabditis elegans embryonic eggshell

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Microsystems & Nanoengineering 2020年第1期6卷 1029-1039页

作者： Roger Krenger jan T.Burri thomas Lehnert Bradley j.Nelson Martin A.M.Gijs Laboratory of Microsystems Ecole Polytechnique Federale de Lausanne1015 LausanneSwitzerland Multi-Scale Robotics Laboratory ETH ZurichZürich 8092Switzerland

Assays focusing on emerging biological phenomena in an animal’s life can be performed during *** the embryo of Caenorhabditis elegans has been extensively studied,its biomechanical properties are largely ***,we demonstrate that cellular force microscopy(CFM),a recently developed technique that combines micro-indentation with high resolution force sensing approaching that of atomic force microscopy,can be successfully applied to *** *** performed,for the first time,a quantitative study of the mechanical properties of the eggshell of living *** embryos and demonstrate the capability of the system to detect alterations of its mechanical parameters and shell defects upon chemical *** addition to investigating natural eggshells,we applied different eggshell treatments,i.e.,exposure to sodium hypochlorite and chitinase solutions,respectively,that selectively modified the multilayer eggshell structure,in order to evaluate the impact of the different layers on the mechanical integrity of the *** element method simulations based on a simple embryo model were used to extract characteristic eggshell parameters from the experimental micro-indentation force-displacement *** found a strong correlation between the severity of the chemical treatment and the rigidity of the ***,our results showed,in contrast to previous assumptions,that short bleach treatments not only selectively remove the outermost vitelline layer of the eggshell,but also significantly degenerate the underlying chitin layer,which is primarily responsible for the mechanical stability of the egg.

关键词： remove rigidity approaching

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Toward Single-Atomic-Layer Lithography on Highly Oriented Pyrolytic Graphite Surfaces Using AFM-Based Electrochemical Etching

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Nanomanufacturing and Metrology 2022年第1期5卷 32-38页

作者： Wei Han Paven thomas Mathew Srikanth Kolagatla Brian j.Rodriguez Fengzhou Fang Centre of Micro/Nano Manufacturing Technology(MNMT-Dublin) University College DublinDublin D04 V1W&I reland Shanghai Engineering Research Centre of Ultra-Precision Optical Manufacturing Fudan UniversityShanghai 200433China School of Physics University College DublinDublin D04 V1W&Ireland Conway Institute of Biomolecular and Biomedical Research University College DublinDublin D04 V1W&Ireland State Key Laboratory of Precision Measuring Technology and Instruments Laboratory of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin 300072China

Atomic force microscopy(AFM)-based electrochemical etching of a highly oriented pyrolytic graphite(HOPG)surface is studied toward the single-atomic-layer lithography of intricate *** etching is performed in the water meniscus formed between the AFM tip apex and HOPG surface due to a capillary effect under controlled high relative humid-ity(~75%)at otherwise ambient *** conditions to etch nano-holes,nano-lines,and other intricate patterns are *** clectrochemical reactions of HOPG etching should not generatc debris duc to the conversion of graphite to gaseous CO and CO_(2)based on etching ***,debris is observed on the etched HOPG surface,and incom-plete gasification of carbon occurs during the etching process,resulting in the generation of solid ***,the applied potential is of critical importance for precise etching,and the precision is also significantly influenced by the AFM tip *** study shows that the AFM-based electrochemical etching has the potential to remove the material in a single-atomic-layer *** result is likely because the etching process is based on anodic dissolution,resulting in the material removal atom by atom.

关键词： Etching Lithography Electrochemical machining Atomic and close-to-atomic scale manufacturing(ACSM)

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Factors explaining the abundance of rodents in the city of Luang Prabang,Lao PDR,as revealed by field and household surveys

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Integrative Zoology 2008年第1期3卷 11-20页

作者： Prasartthong PROMKERD Yuvaluk KHOPRASERT Phongthep VIRATHAVONE Manivone THOUMMABOUTH Ouane SIRISAK thomas jÄKEL Agricultural Zoology Research Group Department of AgricultureBangkokThailand General Service Lao VientianeLao PDR La Maison du Patrimoine Ban Xieng ThongLuang PrabangLao PDR German Technical Cooperation(GTZ) EschbornGermany

A field and a household survey, the latter of which included inspections and interviews with the residents of a totalof 1370 properties, were conducted in 2004 in 30 villages of the city of Luang Prabang, Lao PDR, in order to assessthe degree of rodent infestation and to identify potential factors influencing infestations. Roof rats, Rattus rattus,and the Polynesian rat, Rattus exulans, were the only rodents found in the city, and trapping results showed a cleardominance of roof rats (80–90% of all individuals). Measurements of rodent activity using tracking patchescorrelated positively with the trapping data, and revealed a significantly higher degree of rat infestation during therainy season (September) than during the dry season (November). If households in the vicinity of the samplinglocations were considered, villagers’ accounts of indoor rodent infestations recorded during the household surveycorrelated positively with measurements of rodent activity. At least every second household reported indoorinfestations. Using explorative statistical analyses (classification trees, factor analysis) we checked the predictiveor explanatory value of up to 28 variables assessed during household inspections for villagers’ observations onrodent infestation as the dependent variable. Trophic factors such as exposed food (indoors) and garbage (outdoors),and structural features such as open ceilings (indoors) and rat harborage in gardens (outdoors) ranked highest asexplanatory variables. Assessment of a small sample of roof rat droppings collected inside houses revealed thepresence of the potential disease agents Salmonella javiana, Cryptosporidium parvum, Giardia duodenalis and theparasitic nematode Calodium hepaticum (syn. Capillaria hepatica). These results underline the need for anappropriate rodent management strategy for the city, whereby simple sanitation and rodent-proofing measurescould be cheap means of reducing rat infestation rates.

关键词： household survey Lao PDR Luang Prabang rodent zoonotic disease agent

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An approximate point-based alternative for the estimation of variance under big BAF sampling

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Forest Ecosystems 2021年第3期8卷 439-457页

作者： thomas B.Lynch jeffrey H.Gove Timothy G.Gregoire Mark j.Ducey Professor Emeritus Department of Natural Resource Ecology and ManagementOklahoma State UniversityAg Hall Room 008CStillwater 74078OKUSA USDA Forest Service Northern Research Station271 Mast RoadDurham 03824NHUSA Yale School of Environment Yale University360 Prospect StNew Haven 06511CTUSA Department of Natural Resources and the Environment University of New Hampshire114 James HallDurham 03824NHUSA

Background:A new variance estimator is derived and tested for big BAF(Basal Area Factor)sampling which is a forest inventory system that utilizes Bitterlich sampling(point sampling)with two BAF sizes,a small BAF for tree counts and a larger BAF on which tree measurements are made usually including DBHs and heights needed for volume ***:The new estimator is derived using the Delta method from an existing formulation of the big BAF estimator as consisting of three sample *** new formula is compared to existing big BAF estimators including a popular estimator based on Bruce’s ***:Several computer simulation studies were conducted comparing the new variance estimator to all known variance estimators for big BAF currently in the forest inventory *** simulations the new estimator performed well and comparably to existing variance ***:A possible advantage of the new estimator is that it does not require the assumption of negligible correlation between basal area counts on the small BAF factor and volume-basal area ratios based on the large BAF factor selection trees,an assumption required by all previous big BAF variance estimation *** this correlation was negligible on the simulation stands used in this study,it is conceivable that the correlation could be significant in some forest types,such as those in which the DBH-height relationship can be affected substantially by density perhaps through *** derived a formula that can be used to estimate the covariance between estimates of mean basal area and the ratio of estimates of mean volume and mean basal *** also mathematically derived expressions for bias in the big BAF estimator that can be used to show the bias approaches zero in large samples on the order of 1n where n is the number of sample points.

关键词： Bitterlich sampling Delta method Double sampling Estimator bias Forest inventory Horizontal point sampling Variance of a product Volume basal area ratio Covariance estimation

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A note on the estimation of variance for big BAF sampling

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Forest Ecosystems 2020年第4期7卷 819-832页

作者： jeffrey H.Gove Timothy G.Gregoire Mark j.Ducey thomas B.Lynch USDA Forest Service Northern Research Station271 Mast RoadDurham NH03824USA. School of Forestry&Environmental Studies Yale University360 Prospect StNew Haven CT06511USA. Department of Natural Resources and the Environment University of New Hampshire114 James HallDurham NH03824USA. Professor Emeritus Department of Natural Resource Ecology and ManagementOklahoma State UniversityAg Hall Room 008CStillwater OK74078USA.

Background:The double sampling method known as“big BAF sampling”has been advocated as a way to reduce sampling effort while still maintaining a reasonably precise estimate of volume.A well-known method for variance determination,Bruce’s method,is customarily used because the volume estimator takes the form of a product of random ***,the genesis of Bruce’s method is not known to most foresters who use the method in ***:We establish that the Taylor series approximation known as the Delta method provides a plausible explanation for the origins of Bruce’s *** were conducted on two different tree populations to ascertain the similarities of the Delta method to the exact variance of a ***,two alternative estimators for the variance of individual tree volume-basal area ratios,which are part of the estimation process,were compared within the overall variance estimation ***:The simulation results demonstrate that Bruce’s method provides a robust method for estimating the variance of inventories conducted with the big BAF *** simulations also demonstrate that the variance of the mean volume-basal area ratios can be computed using either the usual sample variance of the mean or the ratio variance estimators with equal accuracy,which had not been shown previously for Big BAF ***:A plausible explanation for the origins of Bruce’s method has been set forth both historically and mathematically in the Delta *** most settings,there is evidently no practical difference between applying the exact variance of a product or the Delta method—either can be used.A caution is articulated concerning the aggregation of tree-wise attributes into point-wise summaries in order to test the correlation between the two as a possible indicator of the need for further covariance augmentation.

关键词： Bitterlich sampling Delta method Double sampling Forest inventory Horizontal point sampling Variance of a product

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Urban and rural decay photography

Urban and rural decay photography

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作者： j. Dennis thomas.

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Elimination of antibiotic resistance genes and control of horizontal transfer risk by UV-based treatment of drinking water: A mini review

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Frontiers of Environmental Science & Engineering 2019年第3期13卷 3-11页

作者： Virender K.Sharma Xin Yu thomas j.McDonald Chetan jinadatha Dionysios D.Dionysiou Mingbao Feng Department of Environmental and Occupational Health School of Public Health Texas A&M University College Station TX 77843 USA Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 China Central Texas Veterans Health Care System Temple TX 76504 USA College of Medicine Texas A&M Health Science Center Bryan TX 77807 USA Environmental Engineering and Science Program Department of Chemical and Environmental Engineering (DChEE) 705 Engineering Research Center University of Cincinnati Cincinnati OH 45221 USA

Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been recognized as one of the biggest public health issues of the 21 st century. Both ARB and ARGs have been determined in water after treatment with conventional disinfectants. Ultraviolet (UV) technology has been seen growth in application to disinfect the water. However, UV method alone is not adequate to degrade ARGs in water. Researchers are investigating the combination of UV with other oxidants (chlorine, hydrogen peroxide (H2O2), peroxymonosulfate (PMS), and photocatalysts) to harness the high reactivity of produced reactive species (C1-, C1O -, Cl2-,-OH, and SO4-_) in such processes with constituents of cell (e.g., deoxyribonucleic acid (DNA) and its components) in order to increase the degradation efficiency of ARGs. This paper briefly reviews the current status of different UV-based treatments (UV/chlorination, UV/H2O2, UV/PMS, and UV-photocatalysis) to degrade ARGs and to control horizontal gene transfer (HGT) in water. The review also provides discussion on the mechanism of degradation of ARGs and application of q-PCR and gel electrophoresis to obtain insights of the fate of ARGs during UV-based treatment processes.

关键词： Antibiotic resistance bacteria Advanced oxidation processes Disinfection Reactive chlorine species Sulfate radicals Reactive oxygen species

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Surface energy-mediated fibronectin adsorption and osteoblast responses on nanostructured diamond

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journal of Materials Science & Technology 2019年第5期35卷 817-823页

作者： Yixing Tian Huiling Liu Brian W.Sheldon thomas j.Webster Sichen Yang Huilin Yang Lei Yang Orthopaedic Institute and Department of Orthopaedics The First Affiliated Hospital Soochow University Suzhou Jiangsu 215006 China School of Engineering Brown University Providence RI 02912 USA Department of Chemical Engineering Northeastern University Boston MA. 02115 USA International Research Center for Translational Orthopaedics (IRCTO) Soochow University Suzhou Jiangsu 215006 China UWC Changshu China Changshu Jiangsu 215500 China

Nanostructured diamond have potential applications in many biomedical related fields and demonstrated extraordinary capacity to influence cellular responses. Studying the surface property of nanodiamond and its influence to protein adsorption and subsequent cellular responses along with the mechanism behind such capacity becomes more important. Here the role of surface energy associated with nanostructured diamond in modulating fibronectin and osteoblast(OB, bone forming cells) responses was investigated. Nanocrystalline diamond(NCD) and submicron crystalline diamond(SMCD) films with controllable surface energy were prepared by microwave-enhanced plasma chemical vapor deposition(MPCVD) techniques. Fibronectin adsorption on the diamond films with varied surface energy values was measured via the enzyme-linked immunosorbent assay(ELISA) and the relationship between the surface energy and fibronectin adsorption was studied. The result indicated that fibronectin adsorption on nanostructured surfaces was closely related to both surface energy and material microstructures. The spreading and migration of OB aggregates(each containing 30–50 cells) on the NCD with varied surface energy values were also studied. The result indicates a correlation between the cell spreading and migration on nanodiamond and the surface energy of nanostructured surface.

关键词： Nanostructure Diamond films Surface characteristics Protein adsorption Cell responses

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ANALYSES OF RECENT GEOMORPHIC EVOLUTION OF GARGATHY INLET, EASTERN SHORE OF VIRGINIA, U. S. A.

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Chinese journal of Oceanology and Limnology 1992年第1期10卷 9-22页

作者：张乔民 R.j.Byrne G.R.thomas South China Sea Institute of Oceanology Academia Sinica Guangzhou 510301 Virginia Institute of Marine Science VA 23062 U.S.A

Uargathy Inlet is a small natural tidal inlet in the northern region ol the Virginia Darner island chain. It is 100 m wide with a throat cross-sectional area of 384m2 and an average tidal prism of 6.47 x 106 m3. The inside drainage system is 7.8 km long and 2.2km wide. The main channels comprise 5.8% of the area, shallow lagoons 19.8%, and Spartina marshes 74.4% in 1970. Over the period 1851 - 1989 the inlet narrowed and migrated northward while maintaining a weakening downdrift offset. The nearby barrier island coastline’s rapid retreat (average rate 4.78m /a, 138 years retreat 660 m) was accompanied by back barrier channel and lagoon filling and a decrease in intertidal water volume which was probably the main reason for the entrance narrowing. The northward migration of the inlet was related to the dredging of the Inside Passage (before 1949) and the breaching of southern Metompkin Island (since 1957) connected with the inlet system. This altered the interior tidal circulation and likely shifted

关键词： geomorphic evolution Gargathy Inlet

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