bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicodynamics of copper and cadmium in Folsomia candida exposed to simulated soil solutions
Authors: Ardestani Masoud M. , van Gestel Cornelis A.M. 
Published: August 2013

Abstract

To improve our understanding of metal bioavailability to soil-living invertebrates, the effect of porewater composition on the toxicodynamics of copper and cadmium in Folsomia candida (Collembola) was investigated. Assuming that porewater is the main exposure route, F. candida was exposed to simulated soil solutions of different composition. Toxicity of copper was slightly lower in a calcium-only solution than in a multication solution. With increasing copper concentrations from 0.005 mM to 1.37 mM, internal copper concentrations similarly increased in both exposure solutions, suggesting that a single cation nutrient solution is suitable for testing F. candida. In the second experiment, animals were exposed for 7 d to copper and cadmium in simplified soil solutions with different calcium (0.2 mM, 0.8 mM, 3.2 mM, 12.8 mM) and pH (5.0, 6.0, 7.0) levels. The median lethal concentration (LC50) values decreased with time in both the calcium and pH series. A hormetic-type effect was observed for copper in the second test, as well as in the calcium-only solution in the first experiment. Because of stronger hormesis, LC50s for copper were higher at lower calcium concentrations. For cadmium, LC50 values were higher at higher calcium concentrations, suggesting competition of calcium with the free cadmium ion. Toxicity of cadmium increased with decreasing pH, while copper was more toxic at intermediate pH. The results show that a toxicodynamics approach can help to improve the interpretation of metal toxicity to soil invertebrates, taking into account soil solution properties. Environ Toxicol Chem 2013;32:2746–2754. © 2013 SETAC
Effects of environmentally realistic daily temperature variation on pesticide toxicity to aquatic invertebrates
Authors: Willming Morgan M. , Qin Guangqiu , Maul Jonathan D. 
Published: August 2013

Abstract

The toxicity of several agricultural chemicals to aquatic invertebrates has been shown to be temperature-dependent, but the role of daily temperature variation has rarely been examined. The authors simulated a natural daily temperature pattern (a fluctuating cycle of 21 °C to 31 °C over a 24-h period) based on field-collected data from Southern High Plains wetlands (TX, USA) and conducted a series of experiments comparing responses from this exposure scenario to a constant exposure at 24 ± 1 °C. Results indicate alterations in pesticide toxicity under the fluctuating temperature regime compared with that of the constant temperature exposure. There was a significant interaction of temperature regime and bifenthrin on Chironomus dilutus survival, and C. dilutus ash-free dry mass was lower in the fluctuating temperature treatment. The 10-d median lethal concentration (LC50) for Hyalella azteca exposed to chlorothalonil was lower under the fluctuating temperature regime compared with the constant temperature regime. For Daphnia magna exposed to malathion, the main effects of temperature regime and malathion were observed on cholinesterase activity. The present study demonstrates how environmentally relevant daily temperature variation influences contaminant effects on aquatic invertebrates. Environ Toxicol Chem 2013;32:2738–2745. © 2013 SETAC
The common ecotoxicology laboratory strain of Hyalella azteca is genetically distinct from most wild strains sampled in Eastern North America
Authors: Major Kaley , Soucek David J. , Giordano Rosanna , Wetzel Mark J. , Soto-Adames Felipe 
Published: August 2013

Abstract

The amphipod Hyalella azteca is commonly used as a model for determining safe concentrations of contaminants in freshwaters. The authors sequenced the mitochondrial cytochrome c oxidase subunit I (COI) gene for representatives of 38 populations of this species complex from US and Canadian toxicology research laboratories and eastern North American field sites to determine their genetic relationships. With 1 exception, all US and Canadian laboratory cultures sampled were identified as conspecific. In 22 wild populations spanning 5 US states and 1 Canadian province, the commonly occurring laboratory species was found only in northern Florida, USA. Therefore, the diversity of the H. azteca species complex detected in the wild is not accurately represented in North American laboratories, questioning the reliability of H. azteca cultures currently in use to accurately predict the responses of wild populations in ecotoxicological assays. The authors also examined the utility of different COI nucleotide fragments presently in use to determine phylogenetic relationships in this group and concluded that saturation in DNA sequences leads to inconsistent relationships between clades. Amino acid sequences for COI were not saturated and may allow a more accurate phylogeny estimate. Hyalella azteca is crucial for developing water-quality regulations; therefore, laboratories should know and standardize the strain(s) they use to confidently compare toxicity tests across laboratories and determine whether they are an appropriate surrogate for their regions. Environ Toxicol Chem 2013;32:2637–2647. © 2013 SETAC
Soil properties affect the toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the enchytraeid worm Enchytraeus crypticus
Authors: Kuperman Roman G. , Checkai Ronald T. , Simini Michael , Phillips Carlton T. , Kolakowski Jan E. , Lanno Roman 
Published: August 2013

Abstract

The authors investigated individual toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the potworm Enchytraeus crypticus using the enchytraeid reproduction test. Studies were designed to generate ecotoxicological benchmarks that can be used for developing ecological soil-screening levels for ecological risk assessments of contaminated soils and to identify and characterize the predominant soil physicochemical parameters that can affect the toxicities of TNT and RDX to E. crypticus. Soils, which had a wide range of physicochemical parameters, included Teller sandy loam, Sassafras sandy loam, Richfield clay loam, Kirkland clay loam, and Webster clay loam. Analyses of quantitative relationships between the toxicological benchmarks for TNT and soil property measurements identified soil organic matter content as the dominant property mitigating TNT toxicity for juvenile production by E. crypticus in freshly amended soil. Both the clay and organic matter contents of the soil modulated reproduction toxicity of TNT that was weathered and aged in soil for 3 mo. Toxicity of RDX for E. crypticus was greater in the coarse-textured sandy loam soils compared with the fine-textured clay loam soils. The present studies revealed alterations in toxicity to E. crypticus after weathering and aging TNT in soil, and these alterations were soil- and endpoint-specific. Environ Toxicol Chem 2013;32:2648–2659. © 2013 SETAC
Changes in cardiovascular function after venlafaxine but not pregabalin in healthy volunteers: a double‐blind, placebo‐controlled study of orthostatic challenge, blood pressure and heart rate
Authors: Diaper Alison , Rich Ann S. , Wilson Sue J. , Craig Kevin , Dourish Colin T. , Dawson Gerry R. , Nutt David J. , Bailey Jayne E. 
Published: August 2013

It is generally thought that venlafaxine raises blood pressure at higher doses; however, some studies have found no effect or a decrease in blood pressure. The aim of this study was to evaluate the cardiovascular (CV) effects of 3 weeks of dosing with venlafaxine, pregabalin and placebo on young healthy adults.Fifty‐four participants, of mean age 23.1 years (sd 4.68), 29 male, were randomised into three parallel groups. Each group received one of the three drugs, dosed incrementally over a 3‐week period to reach daily doses of 150 mg/day venlafaxine and 200 mg/day pregabalin. Blood pressure sphygmomanometer measurements, heart rate measurements, and orthostatic challenges recorded continuously beat‐to‐beat were performed weekly over this period and 5 days after treatment cessation.Results showed resting systolic blood pressure (SBP) and resting and standing diastolic blood pressure (DBP) and heart rate (HR) were significantly raised by venlafaxine compared with the pregabalin and placebo groups. SBP drop on standing was larger, the resulting overshoot was smaller, and recovery was slower on venlafaxine. HR recovery was significantly impaired by venlafaxine. CV changes were observed after only 1 week of dosing at 112.5 mg/day. These effects of venlafaxine are likely to be due to its action of noradrenergic reuptake inhibition. Copyright © 2013 John Wiley & Sons, Ltd.
Postnatal Establishment of Allelic Gαs Silencing as a Plausible Explanation for Delayed Onset of Parathyroid Hormone Resistance Owing to Heterozygous Gαs Disruption
Authors: Turan Serap , Fernandez-Rebollo Eduardo , Aydin Cumhur , Zoto Teuta , Reyes Monica , Bounoutas George , Chen Min , Weinstein Lee S , Erben Reinhold G , Marshansky Vladimir , Bastepe Murat 
Published: August 2013

ABSTRACT

Pseudohypoparathyroidism type-Ia (PHP-Ia), characterized by renal proximal tubular resistance to parathyroid hormone (PTH), results from maternal mutations of GNAS that lead to loss of α-subunit of the stimulatory G protein (Gαs) activity. Gαs expression is paternally silenced in the renal proximal tubule, and this genomic event is critical for the development of PTH resistance, as patients display impaired hormone action only if the mutation is inherited maternally. The primary clinical finding of PHP-Ia is hypocalcemia, which can lead to various neuromuscular defects including seizures. PHP-Ia patients frequently do not present with hypocalcemia until after infancy, but it has remained uncertain whether PTH resistance occurs in a delayed fashion. Analyzing reported cases of PHP-Ia with documented GNAS mutations and mice heterozygous for disruption of Gnas, we herein determined that the manifestation of PTH resistance caused by the maternal loss of Gαs, ie, hypocalcemia and elevated serum PTH, occurs after early postnatal life. To investigate whether this delay could reflect gradual development of paternal Gαs silencing, we then analyzed renal proximal tubules isolated by laser capture microdissection from mice with either maternal or paternal disruption of Gnas. Our results revealed that, whereas expression of Gαs mRNA in this tissue is predominantly from the maternal Gnas allele at weaning (3 weeks postnatal) and in adulthood, the contributions of the maternal and paternal Gnas alleles to Gαs mRNA expression are equal at postnatal day 3. In contrast, we found that paternal Gαs expression is already markedly repressed in brown adipose tissue at birth. Thus, the mechanisms silencing the paternal Gαs allele in renal proximal tubules are not operational during early postnatal development, and this finding correlates well with the latency of PTH resistance in patients with PHP-Ia. © 2014 American Society for Bone and Mineral Research.
Greece, Derivatives, and FX: What Went Wrong?
Authors: Shapiro David M. 
Published: August 2013

AbstractWhat caused the economic collapse of Greece? One factor many people point to was an arrangement between Goldman Sachs and the Greek government. Circa 2001, Greece and Goldman Sachs agreed to do cross‐currency swaps in which the parties exchanged foreign exchange (FX) obligations, which had maturities that stretched over several years. Some say that Greece‐possibly facilitated by Goldman Sachs‐wrongfully concealed these transactions from European Union regulators, and others. That will be determined by the evidence. But the author believes that making OTC swaps or Goldman Sachs a scapegoat for bad investment decisions is a wrongheaded diversion. The more important question is: Were these cross‐currency swaps inherently too hazardous? The author, who has practiced law, public accounting, and investigations for more than 2 decades, unravels this complex story to get at the truth. © 2013 Wiley Periodicals, Inc.
Boredom: The Forgotten Factor in Preventing Worldwide Fraud
Authors: Hollow Matthew 
Published: August 2013

AbstractAre bored workers more likely to commit fraudulent offenses in the workplace worldwide? The author conducts research at the U.K.‐based Institute of Hazard, Risk, and Resilience. In this article, he reveals how a lack of stimulation—or want of productive engagement—among an organization's workforce can significantly increase the risk of financial fraud in the workplace. So CEOs, regulators, and auditors all need to pay greater attention to employees' job satisfaction levels. © 2013 Wiley Periodicals, Inc.
Three‐dimensional morphometric comparison of normal and apoptotic endothelial cells based on laser scanning confocal microscopy observation
Authors: Song Wei , Liu Wenyong , Niu Xufeng , Wang Qingchun , Sun Lianwen , Liu Meili , Fan Yubo 
Published: August 2013

ABSTRACTThree‐dimensional (3D) morphometric analysis of cellular and subcellular structures provides an effective method for spatial cell biology. Here, 3D cellular and nuclear morphologies are reconstructed to quantify and compare morphometric differences between normal and apoptotic endothelial cells. Human umbilical vein endothelial cells (HUVECs) are treated with 60 μM H2O2 to get apoptotic cell model and then a series of sectional images are acquired from laser scanning confocal microscopy. The 3D cell model containing plasma membrane and cell nucleus is reconstructed and fused utilizing three sequential softwares or packages (Mimics, Geomagic, and VTK). The results reveal that H2O2 can induce apoptosis effectively by regulating the activity of apoptosis‐related biomolecules, including pro‐apoptotic factors p53 and Bax, and anti‐apoptotic factor Bcl‐2. Compared with the normal HUVECs, the apoptotic cells exhibit significant 3D morphometric parameters (height, volume and nucleus‐to‐cytoplasm ratio) variation. The present research provides a new perspective on comparative quantitative analysis associated with cell apoptosis and points to the value of LSCM as an objective tool for 3D cell reconstruction. Microsc. Res. Tech. 76:1154–1162, 2013. © 2013 Wiley Periodicals, Inc.
Illustration of Cowling channel coupling to the shear Alfven wave
Authors: Yoshikawa A. , Amm O. , Vanhamäki H. , Fujii R. 
Published: August 2013

AbstractDecomposition of horizontally extended current system into components in the polarization processes and extraction of Cowling channel defined in the companion paper embedded in the total current system are numerically demonstrated. We successfully visualize the background and polarization components in the magnetosphere‐ionosphere coupling process by using the proposed theoretical framework. As a fundamental response, the polarization charge produced by the Pedersen current divergence has a role to cancel and intensify the ambient background electric field inside and outside the high‐conductivity band, respectively. In contrast, the polarization charge produced by the Hall current divergence has a role to rotate the electric field from the background electric field, which causes a meandering of ionospheric convection flow along the boundary of a high‐conductivity band. The Hall and Pedersen currents are always perpendicular to each other. They never close each other when conductances are homogeneous, but they can do that at the conductivity gradient region. This is the reason why a Hall polarization charge is induced and a resultant Cowling channel is formed.
Theory of Cowling channel formation by reflection of shear Alfven waves from the auroral ionosphere
Authors: Yoshikawa A. , Amm O. , Vanhamäki H. , Nakamizo A. , Fujii R. 
Published: August 2013

AbstractWe present the first complete formulation of the coupling between the ionospheric horizontal currents (including Hall currents) and the field‐aligned currents (FAC) via shear Alfven waves, which can describe the formation of a Cowling channel without any a priori parameterization of the secondary (Hall polarization) electric field strength. Our theory reorganizes the Cowling channel by “primary” and “secondary” fields. Until now there are no theoretical frameworks, which can derive these separated components from observed or given total conductance, electric field, and FAC distributions alone. But when a given incident where Alfven wave is considered as the driver, the reflected wave can be uniquely decomposed into the primary and secondary components. We show that the reflected wave can, depending on actual conditions, indeed carry FAC that connect to divergent Hall currents. With this new method, we can identify how large the secondary electric field becomes, how efficiently the divergent Hall current is closed within the ionosphere, and how much of the Hall current continues out to the magnetosphere as FAC. In typical ionospheric situations, only a small fraction of FAC is connected to Hall currents at conductance gradients, i.e., the secondary field is relatively strong. But when conductances are relatively low compared with Alfven conductance and/or horizontal scales smaller than ~10 km, the Hall FAC may become significant.
Mass balance of a maritime glacier on the southeast Tibetan Plateau and its climatic sensitivity
Authors: Yang Wei , Yao Tandong , Guo Xiaofeng , Zhu Meilin , Li Shenghai , Kattel Dambaru B. 
Published: August 2013

AbstractBased on glaciometeorological measurements and mass balance stake records during the 5 year period of 2005–2010 on the southeast Tibetan Plateau, an energy‐mass balance model was applied to study the surface mass balance of the Parlung No. 94 Glacier, as well as its response to regional climate conditions. The primary physical parameters involved in the model were locally calibrated by using relevant glaciometeorological data sets. The good agreement between the snowpack height/mass balance simulations and the in situ measurements available from a total of 12 monitoring stakes over this glacier confirmed the satisfactory performance of the energy‐mass balance model. Results suggested that the recent state of the Parlung No. 94 Glacier was far removed from the “ideal” climatic regime leading to zero mass balance, with its annual mass balance of approximately −0.9 m water equivalent during 2005–2010. Climatic sensitivity experiments were also carried out to interpret the observed mass balance changes, and the experiments demonstrated that the maritime glaciers concerned herein were theoretically more vulnerable to ongoing climate warming on the Tibetan Plateau than potential changes in the amount of precipitation. A plausible causal explanation for the recent glacier shrinkage in this region was concerned with the increasing air temperature. Moreover, both the mass balance simulations and the field measurements indicated that the mass accumulation over this maritime glacier occurred primarily in the boreal spring. Such “spring‐accumulation type” glaciers are presumed to be distributed mainly within a narrow wedge‐shaped region along the Brahmaputra River. Climatic sensitivities of the glacier mass balance are also found to be closely linked to the regional precipitation seasonality that is simultaneously modulated by various atmospheric circulation patterns, such as the southern westerlies, the Bay of Bengal vortex in the spring season, and the Indian monsoon in the summer season.
Effect of imprecise lag time and high‐frequency attenuation on surface‐atmosphere exchange fluxes determined with the relaxed eddy accumulation method
Authors: Moravek A. , Trebs I. , Foken T. 
Published: August 2013

AbstractRelaxed eddy accumulation (REA) systems that employ one single long inlet tube are prone to measurement uncertainties caused by (a) an imprecisely determined lag time between the change of sign in the vertical wind velocity and the switching of the splitter valves and (b) attenuation of high‐frequency concentration fluctuations in the tube flow. However, there is currently no commonly applied procedure to address these uncertainties. In this study, we first evaluated the lag time error of the volume flow, mass flow, and cross‐correlation method (online and offline) and experimentally determined the magnitude of high‐frequency attenuation for a 21.5 m long inlet tube of an operating REA system. In a second step, we simulated the impact for different artificial lag time errors and low‐pass filter strengths on the REA concentration differences and, thus, on the REA flux, using high‐frequency time series of temperature, O3, CO2, and H2O. The reduction of scalar fluxes was mainly correlated with increasing switching frequencies and ranged for typical lag time errors of the investigated REA system between <5% and 50%, whereas the flux loss due to high‐frequency attenuation was between <5% and 30%. The results were very similar for all scalar quantities. Based on our results, we derived empirical correction functions for both imprecise lag times and high‐frequency attenuation, discuss their potential application to correct fluxes measured with other REA systems, and give a general procedure to address the uncertainties in future REA setups.
Procalcitonin‐guided antibiotic therapy: A systematic review and meta‐analysis
Authors: Soni Nilam J. , Samson David J. , Galaydick Jodi L. , Vats Vikrant , Huang Elbert S. , Aronson Naomi , Pitrak David L. 
Published: August 2013

BACKGROUNDThe utility of procalcitonin to manage patients with infections is unclear. A systematic review of comparative studies using procalcitonin‐guided antibiotic therapy in patients with infections was performed.METHODSRandomized, controlled trials comparing procalcitonin‐guided initiation, intensification, or discontinuation of antibiotic therapy to clinically guided therapy were included. Outcomes were antibiotic usage, morbidity, and mortality. MEDLINE, EMBASE, the Cochrane Database, National Institute for Clinical Excellence, the National Guideline Clearinghouse, and the Health Technology Assessment Programme were searched from January 1, 1990 to December 16, 2011.RESULTSEighteen randomized, controlled trials were included. Data were pooled into clinically similar patient populations. In adult intensive care unit (ICU) patients, procalcitonin‐guided discontinuation of antibiotics reduced antibiotic duration by 2.05 days (95% confidence interval [CI]: −2.59 to −1.52) without increasing morbidity or mortality. In contrast, procalcitonin‐guided intensification of antibiotics in adult ICU patients increased antibiotic usage and morbidity. In adult patients with respiratory tract infections, procalcitonin guidance significantly reduced antibiotic duration by 2.35 days (95% CI: −4.38 to −0.33), antibiotic prescription rate by 22% (95% CI: −41% to −4%), and total antibiotic exposure without affecting morbidity or mortality. A single, good quality study of neonates with suspected sepsis demonstrated reduced antibiotic duration by 22.4 hours (P = 0.012) and reduced the proportion of neonates on antibiotics for ≥72 hours by 27% (P = 0.002) with procalcitonin guidance.CONCLUSIONProcalcitonin guidance can safely reduce antibiotic usage when used to discontinue antibiotic therapy in adult ICU patients and when used to initiate or discontinue antibiotics in adult patients with respiratory tract infections. Journal of Hospital Medicine 2013;8:530–540. © 2013 Society of Hospital Medicine