bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple M‐Effect Signal in Noble Gases and Hydrogen Mixture Discharge
Authors: Vladoiu R. , Contulov M. , Ciupina V. , Musa G. 
Published: March 2010

AbstractThe M‐effect (monochromatization‐effect) is a powerful process which can give high intensity monochromatic spectra with a certain wavelength depending on the type of used gas mixtures to generate the plasma state. The effect consists in the emission of a single spectral line emerging from plasma under specific experimental conditions involving one electropositive gas and one electronegative gas mixture. For example, in the case of Ne‐H2 mixture, a clear monochrome radiation was obtained, corresponding to the λNe =585.3 nm wavelength at 2p1‐1s2 transition in the Paschen notation, the pressures ranging between 10‐100 torr.In this paper we prove the general character of this effect, i.e. if the optical emission spectra (OES) reduced to selective lines can be noticed also in other multiple gas mixture discharges. The Ne‐Ar‐Xe mixture discharges with different percentages of H2 as electronegative gas added in has been investigated. The triple M‐effect, means three specific monochromatic lines, could be revealed in the OES at 50% of H2 addition in Ne‐Ar‐Xe mixture (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐affinity folate receptor in cardiac neural crest migration: A gene knockdown model using siRNA
Authors: Rosenquist Thomas H. , Chaudoin Tammy , Finnell Richard H. , Bennett Gregory D. 
Published: March 2010

AbstractFolate supplementation reduces the incidence of congenital heart defects, but the nature of this protective mechanism remains unclear. Immunolabeling demonstrated that the neural tube and neural crest (NC) cells were rich in the high‐affinity folate receptor FOLR1and during the early stages of development FOLR1 was found principally in these cells. Suppression of Folr1 expression in the nascent cardiac NC by site‐directed short‐interfering RNA (siRNA) altered cardiac NC cell mitosis and subsequent migration patterns leading to abnormal development of the pharyngeal arch arteries (PAA) and outflow tract. qPCR analysis demonstrated that the siRNA treatment significantly reduced Folr1 24 hr after treatment. These treatments also significantly reduced mitosis in the neural tube, but adjacent, nontreated areas were unaffected. In summary, a brief reduction in the expression of Folr1 during a critical stage of NC development had long‐term consequences for the development of the PAA and outflow tract. Developmental Dynamics 239:1136–1144, 2010. © 2010 Wiley‐Liss, Inc.
Unusual Coordination Behaviour of a Phosphonate‐ and Pyridine‐Containing Ligand in a Stable Lanthanide Complex
Authors: Gałęzowska Joanna , Janicki Rafał , Kozłowski Henryk , Mondry Anna , Młynarz Piotr , Szyrwiel Łukasz 
Published: March 2010

AbstractAn experimental study of the coordination of lanthanide ions with {ethane‐1,2‐diylbis[imino(pyridin‐2‐ylmethanediyl)]}bis(phosphonic acid), a ligand containing phosphonate and pyridine arms attached to the well‐known ethylenediamine scaffold, is reported. The X‐ray crystal structure of an anionic, octacoordinate EuIII complex of the formula [C(NH2)]6[Eu2(L)2(CO3)2]·8H2O has been obtained and found to contain cyclic dimeric complex anions in which the coordination environment of each EuIII ion is composed of three oxygen atoms from phosphonate groups, two nitrogen atoms from imino groups and one nitrogen atom from a pyridine group, a combination that has seldom been observed for LnIII complexes. In order to check the coordination behaviour of the ligand, an investigation of the complexes in solution has been performed, which revealed a different coordination mode. The protonation constants of the free ligand and the stability constants of their complexes with selected lanthanide ions (LaIII, SmIII, EuIII, GdIII, TbIII, HoIII and LuIII) have been determined potentiometricaly at 25 °C and an ionic strength of 0.1 M (KCl). The results obtained show the formation of monomeric, protonated ([LnH2L], [LnHL]) and nonprotonated ([LnL]) species in the pH range studied (2–11). The determined stability constants (log βLnL) are relatively high, varying between 14.96 and 16.42. The EuIIIL system was also fully characterized by means of UV/Vis spectroscopy, which indicated that the coordination process starts above pH 3 and remains constant in the range pH 4–10. In contrast to the crystal structure, solution NMR and luminescence studies suggested that the pyridine moieties are not present in the LnIII coordination sphere. These results suggest that this ligand–unsaturated metal ion coordination sphere may provide a potential binding site for other target molecules.
Estimation of temporal variation in splash detachment in two Japanese cypress plantations of contrasting age
Authors: Wakiyama Y. , Onda Y. , Nanko K. , Mizugaki S. , Kim Y. , Kitahara H. , Ono H. 
Published: March 2010

AbstractTo elucidate splash erosion processes under natural rainfall conditions, temporal variations in splash detachment were observed using a piezoelectric saltation sensor (H11B; Sensit Co., Portland, ND, USA). Preliminary laboratory tests of Sensit suggested that they were suitable for field observations. Field observations were conducted between July and September 2006 in 21‐ and 36‐year‐old Japanese cypress (Chamaecyparis obtusa) plantations with mean stand heights of 9·2 m and 17·4 m, respectively. Splash detachment (in g m−2) was measured seven times using splash cups, and raindrop kinetic energy (in J m−2 mm−1) in both stands was measured using laser drop‐sizing (LD) gauges. Sensit was installed to record saltation counts, which were converted to temporal data of splash detachment (splash rate; in g m−2 10 min−1) using the relationship between splash detachment and saltation counts. Surface runoff was monitored using runoff plots of 0·5 m width and 2·0 m length to obtain temporal data of flow depth (in millimeters). Both total splash detachment and raindrop kinetic energy were larger in the older stand. Increased splash rates per unit throughfall were found in both stands after rainless durations longer than approximately one day in both stands. However, a lower splash rate was found in the 21‐year stand after rainfall events. During extreme rainstorms, the 21‐year stand showed a low runoff rate and a decline in the splash rate, while the 36‐year stand showed a higher splash rate and increased flow depth. The piezoelectric sensor proved to be a useful means to elucidate splash erosion processes in field conditions. Copyright © 2010 John Wiley & Sons, Ltd.
Dieldrin uptake and translocation in plants growing in hydroponic medium
Authors: Murano Hirotatsu , Otani Takashi , Seike Nobuyasu , Sakai Mizuki 
Published: March 2010

Abstract
It has been known that the Cucurbitaceae family takes up a large amount of persistent organic pollutants from soils and that the translocation of those compounds in cucurbits is higher than those in non-cucurbits. To understand the persistent organic pollutant uptake mechanisms of plant species, we compared the dieldrin absorption and transportation potentials of several plants in hydroponic medium. Sorghum (Sorghum vulgare Moench), sunflower (Helianthus annuus L.), soybean (Glycine max), komatsuna (Brassica rapa var. peruviridis), white-flowered gourd (Lagenaria siceraria var. hispida), cucumber (Cucumis sativus L.), and zucchini (Cucurbita pepo L.) were grown in a dieldrin-added hydroponic medium for 10 d, and then the amount of dieldrin in their shoots and roots was measured. All of the roots contained dieldrin, whereas only the cucurbits (white-flowered gourd, cucumber, and zucchini) contained considerable amounts of dieldrin in their shoots. The dieldrin uptake to the roots depended on the concentration of the n-hexane soluble components in the roots, regardless of whether the dieldrin in the roots was translocated to shoots or not. The dieldrin uptake from the solution to the roots was thought to be due to a passive response, such as adsorption on the roots. The translocation of dieldrin from the roots to the shoots was probably through the xylems. The amounts of dieldrin in the shoots per transpiration rates were higher for cucurbits than for non-cucurbits. It seems likely that cucurbits have uptake mechanisms for hydrophobic organic chemicals. Environ. Toxicol. Chem. 2010;29:142–148. © 2009 SETAC
Insights into the development of fungal biomarkers for metal ecotoxicity assessment: Case ofTrametes versicolorexposed to copper
Authors: Lebrun Jérémie D. , Trinsoutrot-Gattin Isabelle , Laval Karine , Mougin Christian 
Published: March 2010

AbstractThe relationship between the physiological state of fungi and the response of their functional system to metals is not known, limiting the use of fungal enzymes as tools for assessing metal ecotoxicity in terrestrial ecosystems. The present study attempts to establish how the development phases modulate the secretion of enzymes in the filamentous fungus Trametes versicolor after exposure to Cu. For that purpose, extracellular hydrolases (acid and alkaline phosphatases, aryl-sulfatase, β-glucosidase, β-galactosidase, and N-acetyl-β-glucosaminidase) and oxidoreductases (laccase, manganese and lignin peroxidases) were monitored in liquid cultures for 2 weeks. Copper was added during either the growth or the stationary phases at 20 or 200 ppm. Results of the present study showed that Cu at the highest concentration modifies the secretion of enzymes, regardless of the development phase to which the fungus was exposed. However, the sensitivity of enzyme responses to Cu depended on the phase development and the type of secreted enzyme. In a general way, the production of hydrolases was decreased by Cu, whereas that of oxidoreductases was highly increased. Furthermore, lignin peroxidase was not detected in control cultures and was specifically produced in the presence of Cu. In conclusion, fungal oxidoreductases may be enzymatic biomarkers of copper exposure for ecotoxicity assessment. Environ. Toxicol. Chem. 2010;29:902–908. © 2009 SETAC
Bioavailability of decabromodiphenyl ether to the marine polychaeteNereis virens
Authors: Klosterhaus Susan L. , Baker Joel E. 
Published: March 2010

AbstractThe flame retardant decabromodiphenyl ether (BDE 209) accumulates in humans and terrestrial food webs, but few studies have reported the accumulation of BDE 209 in aquatic biota. To investigate the mechanisms controlling the bioavailability of BDE 209, a 28-d bioaccumulation experiment was conducted in which the marine polychaete worm Nereis virens was exposed to a decabromodiphenyl ether (deca-BDE) commercial mixture (&gt;85% BDE 209) in spiked sediments, in spiked food, or in field sediments. Bioaccumulation from spiked substrate with maximum bioavailability demonstrated that BDE 209 accumulates in this species. Bioavailability depends on the exposure conditions, however, because BDE 209 in field sediments did not accumulate (&lt;0.3 ng/g wet weight; 28-d biota-sediment accumulation factors [BSAFs] &lt;0.001). When exposed to deca-BDE in spiked sediments also containing lower brominated congeners (a penta-BDE mixture), bioaccumulation of BDE 209 was 30 times lower than when exposed to deca-BDE alone. Selective accumulation of the lower brominated congeners supports their prevalence in higher trophic level species. The mechanisms responsible for limited accumulation of BDE 209 may involve characteristics of the sediment matrix and low transfer efficiency in the digestive fluid. Environ. Toxicol. Chem. 2010;29:860–868. © 2009 SETAC
Quantifying the antiestrogen activity of wastewater treatment plant effluent using the yeast estrogen screen
Authors: Buckley James A. 
Published: March 2010

Abstract
The yeast estrogen screen (YES) assay was used to measure both estrogenic and antiestrogenic activity of wastewater treatment plant (WWTP) effluent for the purpose of developing a method to quantify antiestrogenic activity. Wastewater treatment plant effluent samples were concentrated by solid-phase extraction (SPE) and serially diluted. Five microliters of each dilution plus 195 µl of assay medium was placed in well plates and tested for estrogenic substances. Antiestrogen activity in WWTP effluent samples was indirectly measured by an effluent-volume–dependent suppression of the β-galactosidase activity induced by an estradiol (E2) standard. Antiestrogens and estrogens were quantified by median inhibition concentration (IC50) and median effective concentration (EC50) statistics, respectively, and were expressed in terms of effluent volume (prior to concentration by SPE). Antiestrogen IC50 and estrogen EC50 values, calculated by standard linear regression methods, averaged 25.6 µl and 22.1 µl effluent, respectively. Taken together, these values suggest that antiestrogens were responsible for approximately a 50% reduction in estrogen-induced activity in WWTP effluent. Therefore, measurements of estrogenicity by the YES assay in WWTP effluent that typically contains a mixture of estrogenic and antiestrogenic substances should be considered net estrogenic activity. The potential for false-positive antiestrogen activity was addressed by assays of β-galactosidase activity in effluent, by measurements of yeast cell turbidity, and by stirred cell ultrafiltration for removal of solid-phase coextracted organic substances. Environ. Toxicol. Chem. 2010;29:73–78. © 2009 SETAC
Spatial patterns of atmospherically deposited organic contaminants at high elevation in the southern Sierra Nevada mountains, California, USA
Authors: Bradford David F. , Stanley Kerri , McConnell Laura L. , Tallent-Halsell Nita G. , Nash Maliha S. , Simonich Staci M. 
Published: March 2010

Abstract
Atmospherically deposited contaminants in the Sierra Nevada mountains of California, USA have been implicated as adversely affecting amphibians and fish, yet little is known about the distributions of contaminants within the mountains, particularly at high elevation. The hypothesis that contaminant concentrations in a high-elevation portion of the Sierra Nevada decrease with distance from the adjacent San Joaquin Valley was tested. Air, sediment, and tadpoles were sampled twice at 28 water bodies in 14 dispersed areas in Sequoia and Kings Canyon National Parks (2,785–3,375 m elevation; 43–82 km from Valley edge). Up to 15 chemicals were detected frequently in sediment and tadpoles, including current- and historic-use pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. Only β-endosulfan was found frequently in air. Concentrations of all chemicals detected were very low, averaging in the parts-per-billion range or less in sediment and tadpoles, and on the order of 10 pg/m3 for β-endosulfan in air. Principal components analysis indicated that chemical compositions were generally similar among sites, suggesting that chemical transport patterns were likewise similar among sites. In contrast, transport processes did not appear to strongly influence concentration differences among sites, because variation in concentrations among nearby sites was high relative to sites far from each other. Moreover, a general relationship for concentrations as a function of distance from the valley was not evident across chemical, medium, and time. Nevertheless, concentrations for some chemical/medium/time combinations showed significant negative relationships with metrics for distance from the Valley. However, the magnitude of these distance effects among high-elevation sites was small relative to differences found in other studies between the valley edge and the nearest high-elevation sites. Environ. Toxicol. Chem. 2010;29:1056–1066. © 2010 SETAC
Relationship between laying sequence and mercury concentration in tree swallow eggs
Authors: Brasso Rebecka L. , Abdel Latif Marwa K. , Cristol Daniel A. 
Published: March 2010

Abstract
When female birds lay eggs, some of their body burden of mercury is eliminated into each egg, potentially leading to declining mercury across the clutch. However, there was no decline in mercury with laying sequence in clutches of tree swallow (Tachycineta bicolor) eggs at a mercury-contaminated site, presumably due to daily replenishment of mercury in females during laying. Sampling just one egg from the nest provided an accurate measure of clutch mercury contamination. Environ. Toxicol. Chem. 2010;29:1155–1159. © 2010 SETAC
Extent of copper tolerance and consequences for functional stability of the ammonia-oxidizing community in long-term copper-contaminated soils
Authors: Mertens Jelle , Wakelin Steven A. , Broos Kris , McLaughlin Mike J. , Smolders Erik 
Published: March 2010

AbstractAdaptation of soil microbial communities to elevated copper (Cu) concentrations has been well documented. However, effects of long-term Cu exposure on adaptation responses associated with functional stability and structural composition within the nitrifying community are still unknown. Soils were sampled in three field sites (Denmark, Thailand, and Australia) where Cu gradients had been established from 3 to 80 years prior to sampling. In each field site, the potential nitrification rate (PNR) decreased by over 50% with increasing soil Cu, irrespective of a 20 to &gt;200-fold increase in Cu tolerance (at the highest soil Cu) among the nitrifying communities. This increased tolerance was associated with decreasing numbers (15–120-fold) of ammonia-oxidizing bacteria (AOB), except in the oldest contaminated field site, decreasing numbers of ammonia-oxidizing archaea (AOA; 10–130-fold) and differences in the operational taxonomic unit (OTU) composition of the AOB and, to a lesser extent, AOA communities. The sensitivity of nitrifying communities, previously under long-term Cu exposure, to additional stresses was assessed. Nitrification in soils from the three field sites was measured following acidification, pesticide addition, freeze–thaw cycles, and dry–rewetting cycles. Functional stability of the nitrification process was assessed immediately after stress application (resistance) and after an additional three weeks of incubation (resilience). No indications were found that long-term Cu exposure affected the sensitivity to the selected stressors, suggesting that resistance and resilience were unaffected. It was concluded that the nitrifying community changed structurally in all long-term Cu-exposed field sites and that these changes were associated with increased Cu tolerance but not with a loss of functional stability. Environ. Toxicol. Chem. 2010;29:27–37. © 2009 SETAC
Toxicities of fipronil enantiomers to the honeybee Apis mellifera L. and enantiomeric compositions of fipronil in honey plant flowers
Authors: Li Xiqing , Bao Chen , Yang Daibin , Zheng Mingqi , Li Xuefeng , Tao Shu 
Published: March 2010

Abstract
Fipronil is a chiral phenylpyrazole insecticide that is effective for control of a wide range of agricultural and domestic pests at low application rates. Wide application of fipronil also causes poisoning of some nontarget insects, such as honeybees. In the present study, toxicities of fipronil enantiomers and racemate to the honeybee Apis mellifera L. were determined to examine whether using formulations of single or enriched fipronil enantiomer is a possible option to reduce risks to bees. Contact toxicity tests yielded median lethal doses (LD50) of 3.45, 3.38, and 3.86 ng/bee for the R(−)-enantiomer, S(+)-enantiomer, and racemate, respectively. Analysis of variance indicates that the LD50 values are not statistically different (p = 0.41). Oral toxicities of the R-enantiomer, S-enantiomer, and racemate (nominal median lethal concentration = 0.037, 0.045, 0.053 mg/L, respectively) were also demonstrated to be not statistically different (p = 0.20). In addition, enantiomeric fractions of fipronil in the flowers of three honey plants (Brassica campestris, Cucumis sativus, and Chrysanthemum indicum L.) were examined after treatment with fipronil. It was found that degradation of fipronil in all three plants is not enantioselective. These results indicate that it is unlikely that use of formulations with single or enriched fipronil enantiomer would reduce the risk that fipronil poses to honeybees. Improved fipronil application practices (based on safest timing and bloom conditions) and reduction of overall fipronil usage seem to be more realistic options. Environ. Toxicol. Chem. 2010;29:127–132. © 2009 SETAC
Binding of ciprofloxacin by humic substances: A molecular dynamics study
Authors: Aristilde Ludmilla , Sposito Garrison 
Published: March 2010

Abstract
A comprehensive assessment of the potential impacts of antimicrobials released into the environment requires an understanding of their sequestration by natural particles. Of particular interest are the strong interactions of antimicrobials with natural organic matter (NOM), which are believed to reduce their bioavailability, retard their abiotic and biotic degradation, and facilitate their persistence in soils and aquatic sediments. Molecular dynamics (MD) relaxation studies of a widely used fluoroquinolone antibiotic, ciprofloxacin (Cipro), interacting with a model humic substance (HS) in a hydrated environment, were performed to elucidate the mechanisms of these interactions. Specifically, a zwitterionic Cipro molecule, the predominant species at circumneutral pH, was reacted either with protonated HS or deprotonated HS bearing Ca, Mg, or Fe(II) cations. The HS underwent conformational changes through rearrangements of its hydrophobic and hydrophilic regions and disruption of its intramolecular H-bonds to facilitate favorable intermolecular H-bonding interactions with Cipro. Complexation of the metal cations with HS carboxylates appeared to impede binding of the positively charged amino group of Cipro with these negatively charged HS complexation sites. On the other hand, an outer-sphere complex between Cipro and the HS-bound cation led to ternary Cipro–metal–HS complexes in the case of Mg–HS and Fe(II)–HS, but no such bridging interaction occurred with Ca–HS. The results suggested that the ionic potential (valence/ionic radius) of the divalent cation may be a determining factor in the formation of the ternary complex, with high ionic potential favoring the bridging interaction. Environ. Toxicol. Chem. 2010;29:90–98. © 2009 SETAC