bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unraveling a municipal effluent's toxicity to Tripneustes gratilla sperm fertilization
Authors: Vazquez Lourdes C. 
Published: February 2013

Abstract

A tiered investigative approach was employed to characterize and identify substances responsible for the persistent toxicity of a primary-treated municipal effluent to gametes of the Hawaiian sea urchin, Tripneustes gratilla. Toxicity identification evaluation (TIE) procedures from the US Environmental Protection Agency were modified to account for the tolerance of T. gratilla gametes to various sample manipulations. Microtox rapid toxicity screening was applied in some aspects of the study after verifying a correlation between the pattern of toxic responses of T. gratilla gametes and that of the bioluminescent bacteria Vibrio fischeri. Toxicity identification evaluation phase I manipulations revealed a toxicity profile implicating surfactants as possible toxicants, and TIE phase II toxicity assessment of isolated fractions coupled with colorimetric surfactant analyses confirmed the possible role of surfactants in effluent toxicity. The toxic effects of standard reference surfactants on T. gratilla fertilization indicated a concordance with the effects of the more nonpolar effluent fractions. Treatability studies showed that biodegradation by activated sludge eliminated effluent toxicity to urchin gametes. Environ Toxicol Chem 2013;32:1382–1387. © 2013 SETAC
Risk assessment using the species sensitivity distribution method: Data quality versus data quantity
Authors: Dowse Renee , Tang Doudou , Palmer Carolyn G. , Kefford Ben J. 
Published: February 2013

Abstract

Species sensitivity distributions (SSDs) are cumulative distributions of measures of species sensitivity to a stressor or toxicant, and are used to estimate concentrations that will protect p% of a community (PCp). There is conflict between the desire to use high-quality sensitivity data in SSDs, and to construct them with a large number of species forming a representative sample. Trade-offs between data quality and quantity were investigated using the effects of increasing salinity on the macroinvertebrate community from the Hunter River catchment, in eastern Australia. Five SSDs were constructed, representing five points along a continuum of data quality versus data quantity and representativeness. This continuum was achieved by the various inclusion/exclusion of censored data, nonmodeled data, and extrapolation from related species. Protective concentrations were estimated using the Burr type III distribution, Kaplan-Meier survival function, and two Bayesian statistical models. The dominant taxonomic group was the prime determinant of protective concentrations, with an increase in PC95 values resulting from a decrease in the proportion of Ephemeropteran species included in the SSD. In addition, decreases in data quantity in a SSD decreased community representativeness. The authors suggest, at least for salinity, that the inclusion of right censored data provides a more representative sample of species that reflects the natural biotic assemblage of an area to be protected, and will therefore improve risk assessment. Environ Toxicol Chem 2013;32:1360–1369. © 2013 SETAC
Toxicological implications of microcystins for zebrafish embryos in the presence of other environmental pollutants
Authors: Pavagadhi Shruti , Gong Zhiyuan , Balasubramanian Rajasekhar 
Published: February 2013

Abstract

Microcystins (MCs) interact with environmental contaminants as well as various other congeners of the MC family in the natural environment and with antioxidants in the exposed organisms. These interactions are likely to modify the toxicological behavior of MCs at the cellular level. The present study was conducted to determine the toxicological response of extracellular MCs in aquatic systems under environmentally relevant conditions. Microcystin–leucine–arginine (MCLR) and microcystin–arginine–arginine (MCRR) were introduced at different concentrations in a single-component (MCLR or MCRR) or dual-component (MCLR and MCRR) system to zebrafish embryos in the presence of inorganic elements (Hg, As, Pb, and Cd) and nutrient species (NO3−, PO43−, and Cl−1). Hatchability, heart rate, and mortality of zerbrafish embryos were monitored together with changes in the activity of glutathione-S-transferase (GST) to evaluate their response on exposure to MCLR and MCRR. There was a significant reduction in all these parameters at higher doses of MCLR and MCRR (&gt;100 ng/mL), implying bioaccumulation of these MCs in embryos and adverse effects on early development stages of the fish. It was further observed that PO43−and Cl− enhanced the toxic effects of MCLR and MCRR while NO3− attenuated their toxic effects. In contrast, all 4 toxic elements together increased the toxicity of MCLR and MCRR to embryos compared with their single-component counterparts. Thus, the toxic effects of MCs depend not only on their relative environmental concentrations, but also on those of other environmental pollutants and the levels of antioxidants in exposed organisms. Environ Toxicol Chem 2013;32:1574–1581. © 2013 SETAC
Mathematical relationships between metrics of chemical bioaccumulation in fish
Authors: Mackay Don , Arnot Jon A. , Gobas Frank A.P.C. , Powell David E. 
Published: February 2013

Abstract

Five widely used metrics of bioaccumulation in fish are defined and discussed, namely the octanol–water partition coefficient (KOW), bioconcentration factor (BCF), bioaccumulation factor (BAF), biomagnification factor (BMF), and trophic magnification factor (TMF). Algebraic relationships between these metrics are developed and discussed using conventional expressions for chemical uptake from water and food and first-order losses by respiration, egestion, biotransformation, and growth dilution. Two BCFs may be defined, namely as an equilibrium partition coefficient KFW or as a nonequilibrium BCFK in which egestion losses are included. Bioaccumulation factors are shown to be the product of the BCFK and a novel equilibrium multiplier M containing 2 ratios, namely, the diet-to-water concentration ratio and the ratio of uptake rate constants for respiration and dietary uptake. Biomagnification factors are shown to be proportional to the lipid-normalized ratio of the predator/prey values of BCFK and the ratio of the equilibrium multipliers. Relationships with TMFs are also discussed. The effects of chemical hydrophobicity, biotransformation, and growth are evaluated by applying the relationships to a range of illustrative chemicals of varying KOW in a linear 4-trophic-level food web with typical values for uptake and loss rate constants. The roles of respiratory and dietary intakes are demonstrated, and even slow rates of biotransformation and growth can significantly affect bioaccumulation. The BCFKs and the values of M can be regarded as the fundamental determinants of bioaccumulation and biomagnification in aquatic food webs. Analyzing data from food webs can be enhanced by plotting logarithmic lipid-normalized concentrations or fugacities as a linear function of trophic level to deduce TMFs. Implications for determining bioaccumulation by laboratory tests for regulatory purposes are discussed. Environ Toxicol Chem 2013;32:1459–1466. © 2013 SETAC
A multivariate analysis approach to the study of chemical and functional properties of chemo‐diverse plant derivatives: lavender essential oils
Authors: Maietti Silvia , Rossi Damiano , Guerrini Alessandra , Useli Chiara , Romagnoli Carlo , Poli Ferruccio , Bruni Renato , Sacchetti Gianni 
Published: February 2013

ABSTRACTSix lavender essential oils, L. angustifolia and five Lavandula x hybrida cultivars (Super Z, Abrialis, R.C., Alardii and Ordinario), were evaluated from a phytochemical and biological standpoint, and the results were computed by using multivariate data analysis. The essential oils were analysed by gas chromatography, gas chromatography–mass spectrometry and headspace gas‐chromatography. Multivariate analyses (principal component analysis) identified three main phytochemical clusters among lavender essential oils, represented by 1,8‐cineole, linalyl acetate and linalool. Functional properties of the essential oils were checked by (1) estimating cytotoxicity and genotoxicity using the Saccharomyces cerevisiae D7 strain; (2) determining antifungal activity against three common phytopathogens (Pythium ultimum, Magnaporthe grisea and Botrytis cinerea), by performing an agar vapour bioassay; and (3) calculating the antioxidant capacity by using the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and β‐carotene bleaching tests. No mutagenic effects were detected, but multivariate analyses (PLS, partial least squares regression) showed that the essential oils belonging to the linalool cluster were the most cytotoxic. Antifungal activity against phytopathogens confirmed the predictive results of PLS. The differences among lavender essential oils regarding weak antioxidant capacity showed a positive relationship between the high polarity compounds and the DPPH method, as determined by PLS. The opposite effect was shown for the same type of compound and β‐carotene. Ketones and esters did not exert any significant antioxidant activity. In conclusion, taking lavender essential oils as a model and computing multivariate data of a reduced number of parameters, the proposed approach assured the description of the relationship between a phytocomplex, its constituents and bioactivities, and allowed a comprehensive, predictive approach to be defined, for which the chemical profile provides a possible synergic overall effort in terms of applicative perspectives. Copyright © 2013 John Wiley & Sons, Ltd.
Review:In vitrobiofilm models for studying oral malodour
Authors: Greenman John , Saad Saliha , Hewett Keith , Thorn Robin M. S. , Reynolds Darren M. 
Published: February 2013

ABSTRACTMost cases of oral malodour are thought to be due to microbial biofilms that form in the pits and fissures that exist on the dorsum of the tongue. The tongue microflora is mainly fed by saliva, but nutrient sources could also include exfoliated mammalian cells and tissue fluid (e.g. crevicular fluid) which may bring high concentrations of sulfur‐containing substrates. In addition, consumed food could also contribute nutrients to a lesser degree. The collective microbial biofilm metabolism breaks down proteins, peptides and glycoproteins into cell transportable monomers, including sugars and amino acids. A significant portion of the biofilm can convert nutrient substrates into volatile organic compounds (VOCs), including odiferous volatile sulfur compounds (VSCs). A number ofin vitrobiofilm models have been developed to study the generation and inhibition of microbial oral malodour. Dynamic steady‐state models coupled with real‐time monitoring of VOCs seems to offer advantages over models based on batch sampling from batch culture. Copyright © 2013 John Wiley & Sons, Ltd.
The Effect of Adding Ce1–xSmxO2–x/2 with Different Sm Contents on the Electrochemical Performance of GdBaCo2O5+δ Based Composite Cathode
Authors: Li N. , Lü Z. , Wei B. , Huang X. Q. , Zhang Y. H. , Zhu X. B. , Su W. H. 
Published: February 2013

AbstractIn this paper, the Ce1–xSmxO2–x/2 (x = 0.025, 0.05, 0.1, 0.2) samples were synthesized and then mixed with GdBaCo2O5+δ (GBCO) to form GBCO–Ce1–xSmxO2–x/2 composite cathodes. The electrochemical performance of the composite cathodes was investigated by the electrochemical impedance spectroscopy (EIS) as a function of temperature and oxygen partial pressure. The impedance spectra results demonstrated that the introduction of proper Ce1–xSmxO2–x/2 phase remarkably enhanced the electrochemical performance of GBCO cathode and caused a reduction in the total polarization resistance (Rp). Furthermore, as the amount of Ce1–xSmxO2–x/2 in composite cathode was fixed, the variation of Sm content in Ce1–xSmxO2–x/2 also had a significant influence on the electrochemical performance of the GBCO–Ce1–xSmxO2–x/2 cathodes. For example, the Rp of GBCO cathodes containing 10 wt.% Ce1–xSmxO2–x/2 considerably reduced from 0.37 to 0.17 Ω cm2 at 600 °C with the decreasing Sm content x from 0.2 to 0.025. The improvement in performance of the GBCO–Ce1–xSmxO2–x/2 cathodes compared to pure GBCO cathode could be mainly attributed to the catalytic activity of Ce1–xSmxO2–x/2 towards the surface diffusion related processes, which was an elementary step in oxygen reduction reaction at cathode.
Bid–Ask Spreads and Implied Volatilities of Key Players in a FX Options Market
Authors: Galai Dan , Schreiber Ben Z. 
Published: February 2013

AbstractThis study proposes a simultaneous estimation of the bid–ask spreads (BAS) and implied volatility (IV), based on trading options of various key players in the Israeli OTC FX options market. It explores the surface shape of both variables based on a “clientele effect.” We employ detailed data on OTC foreign exchange options trading that enable us to examine the behavior of the key players (financial companies, non‐financial firms, households, and foreign investors) during relatively turbulent and tranquil periods. Using simultaneous unbiased estimates of BAS and IV, we find substantial differences in BASs among key players while insignificant differences in IV. This evidence reflects differences in key players' profile such as trading size, sophistication and contestability on one hand and a “no arbitrage opportunities” of IV on the other hand. © 2013 Wiley Periodicals, Inc. Jrl Fut Mark
Deep‐sea nutrient loss inferred from the marine dissolved N2/Ar ratio
Authors: Hamme Roberta C. , Emerson Steven R. 
Published: February 2013

AbstractSome estimates of the budget of bioavailable nitrogen (fixed‐N) suggest that the oceanic nitrogen cycle is grossly out of balance. We use observations of dissolved N2/Ar ratios along abyssal flow paths in the ocean to investigate fixed‐N loss by benthic denitrification, one of the largest uncertainties. Dissolved N2/Ar in the deep‐sea increases from the North Atlantic to the North Pacific. At depths >3500 m, this can be explained by the mixing of low N2/Ar source waters from the North Atlantic with high N2/Ar source waters from the Southern Ocean. Benthic denitrification in sediments bathed by these abyssal waters is below the detection limit. However, measureable increases in N2/Ar at depths of 2000–3000 m between the subtropical and subarctic North Pacific, regions that share the same source water, must be caused by benthic denitrification. The Cascadia Basin, with high denitrification rates and connection to the open North Pacific, is a likely source.
Vegetation and wildfire controls on sediment yield in bedrock landscapes
Authors: DiBiase Roman A. , Lamb Michael P. 
Published: February 2013

AbstractSteep, rocky landscapes commonly exhibit high sediment yields and are especially sensitive to climate, tectonics, and wildfire. Predicting landscape response to these perturbations demands a quantitative understanding of erosion processes. However, existing models for hillslope sediment production and transport do not apply to landscapes with patchy soil and slopes that exceed the angle for sediment stability. Here we present field measurements in southern California, USA, which indicate that sediment storage on steep slopes is enabled by vegetation that traps sediment upslope. We find that the storage capacity of unburned vegetation dams follows a geometric scaling model with a cubic dependence on effective plant width and an inverse dependence on local slope. Measured sediment volumes behind burned vegetation dams indicate a loss of at least 75% relative to unburned dams, and when expanded to the catchment scale, our measurements match records of postfire sediment yield from nearby retention basins. Contrary to existing models, our observations indicate that wildfire‐induced sediment yield is driven by transient storage and release of sediment by vegetation dams, rather than increased bedrock‐to‐soil conversion rates. Without a feedback between soil production and wildfire, fire may play little role in long‐term landscape evolution, and increasing fire frequency in response to climate change may not result in heightened sedimentation hazards due to supply limitations.
How to improve the representation of hydrological processes in SWAT for a lowland catchment – temporal analysis of parameter sensitivity and model performance
Authors: Guse Björn , Reusser Dominik E. , Fohrer Nicola 
Published: February 2013

AbstractModel diagnostic analyses help to improve the understanding of hydrological processes and their representation in hydrological models. A detailed temporal analysis detects periods of poor model performance and model components with potential for model improvements, which cannot be found by analysing the whole discharge time series.In this study, we aim to improve the understanding of hydrological processes by investigating the temporal dynamics of parameter sensitivity and of model performance for the Soil and Water Assessment Tool model applied to the Treene lowland catchment in Northern Germany. The temporal analysis shows that the parameter sensitivity varies temporally with high sensitivity for three groundwater parameters (groundwater time delay, baseflow recession constant and aquifer fraction coefficient) and one evaporation parameter (soil evaporation compensation factor). Whereas the soil evaporation compensation factor dominates in baseflow and resaturation periods, groundwater time delay, baseflow recession constant and aquifer fraction coefficient are dominant in the peak and recession phases. The temporal analysis of model performance identifies three clusters with different model performances, which can be related to different phases of the hydrograph. The lowest performance, when comparing six performance measures, is detected for the baseflow cluster. A spatially distributed analysis for six hydrological stations within the Treene catchment shows similar results for all stations.The linkage of periods with poor model performance to the dominant model components in these phases and with the related hydrological processes shows that the groundwater module has the highest potential for improvement. This temporal diagnostic analysis enhances the understanding of the Soil and Water Assessment Tool model and of the dominant hydrological processes in the lowland catchment. Copyright © 2013 John Wiley & Sons, Ltd.
Egg wash wastewater: Estrogenic risk or environmental asset?
Authors: Shappell Nancy W 
Published: February 2013

Abstract
Commercial production of eggs and egg products requires the washing of eggs to remove urinary-fecal material and broken egg residue. In the case of one Ohio farming facility, 1.6 million birds produce 1.4 million eggs per day, using approximately 50 mL of wash water/egg or approximately 70 000 L per day. The aqueous waste stream was evaluated for estrogenicity to determine if potential for endocrine disruption would result from agricultural application of such wastewater. Samples collected the Fall (October) of 2010 included: water from 2 egg washers operating in series, inlet pipe to the treatment lagoon, a lagoon composite, and products used within the facility in the cleaning of equipment and treatment of the waste. In February 2011, the treatment lagoon was fitted with an extensive aeration system and subsequent sample sets were collected on 3 consecutive days in May and November. Samples were extracted by solid phase extraction and assayed for estrogenic activity using the in vitro E-Screen assay. Raw untreated wastewater from the egg washers contained 17β-estradiol equivalents (E2Eqs) ranging from 9 to 18 ng/L, pipe grab samples entering into the treatment lagoon ranged from &lt;0.14 to 4.4 ng/L (variability related to time of emptying of egg wash tanks), whereas treatment lagoon water contained 0.3 to 4.0 ng/L E2Eq. Addition of an aeration system to the treatment lagoon eliminated surface “frothing,” reduced noxious odor emission, and E2Eqs were lower than the pre-aeration concentrations (4 ng/L [n = 1, no statistical comparison possible] vs 0.3 to 1.4 ng/L in 2011). Because of matrix effects, estrogens were not quantifiable by LC-MS2 in even egg washwater extracts, at concentrations in which internal deuterated estrogen standards were quantifiable. Estrone and E2 parent ions were detected in egg washwater samples only, and confirmatory ion fragments were detected in only one of these samples. Estrogenicity of the wastewater from the treatment lagoon was already at the proposed aquatic no effect concentration for 17β-E2 and would be expected to decrease further as wastewater passes through 2 consecutive storage ponds before application on field crops for irrigation. The original project plan was to follow the wastewater as it was applied by aerial irrigation and concomitant surface runoff, but based on the consistent and extremely low concentration of estrogenic activity of the wastewater from the treatment lagoon, it was concluded that activity would be below limits of quantitation by E-Screen in water used for irrigation from the storage ponds. Use of egg wash wastewater—or gray water—to irrigate crops removes the cost and burden of wastewater treatment by the local wastewater plant, poses little to no potential threat of estrogenic endocrine disruption, and supports the conservation of water resources through the use of wastewater irrigation. Integr Environ Assess Manag 2013;9:517–523. © 2013 SETAC
Mitochondrial energetic metabolism—some general principles
Authors: Mazat Jean‐Pierre , Ransac Stéphane , Heiske Margit , Devin Anne , Rigoulet Michel 
Published: February 2013

AbstractSummaryIn nonphotosynthetic organisms, mitochondria are the power plant of the cell, emphasizing their great potentiality for adenosine triphosphate (ATP) synthesis from the redox span between nutrients and oxygen. Also of great importance is their role in the maintenance of the cell redox balance. Even though crystallographic structures of respiratory complexes, ATP synthase, and ATP/adenosine diphosphate (ADP) carrier are now quite well known, the coupling between ATP synthesis and cell redox state remains a controversial issue. In this review, we will present some of the processes that allow a modular coupling between ATP synthesis and redox state. Furthermore, we will present some theoretical approaches of this highly integrated system. © 2013 IUBMB Life, 65(3):171–179, 2013