bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transplacental transfer of organochlorines in california sea lions (Zalophus californianus)
Authors: Greig Denise J. , Ylitalo Gina M. , Hall Ailsa J. , Fauquier Deborah A. , Gulland Frances M.D. 
Published: December 2006

Abstract
The transplacental transfer of organochlorines (OCs) in California sea lions (Zalophus californianus) was investigated by analyzing blubber samples from 20 female sea lions and their fetuses during the last trimester of pregnancy. A rapid, high-performance liquid chromatographic, photodiode-array method was used to measure blubber concentrations of polychlorinated biphenyls (PCBs), including dioxin-like congeners, as well as DDTs and hexachlorobenzene. Summed values of PCBs (ΣPCBs), of DDTs (ΣDDTs), and of PCB toxic equivalents (ΣPCB TEQs) were calculated from these data. The ratios of mean blubber concentrations of fetal ΣPCBs to maternal blubber concentrations of ΣPCBs were 0.45 by wet weight and 0.97 by lipid weight, but these ratios varied widely among mother–fetus pairs. Mean ratios of fetal ΣDDTs to maternal ΣDDTs were 0.53 by wet weight and 1.12 by lipid weight. Fetuses were classified into two age groups, based on date of recovery, to examine differences in OC transfer because of gestational age. Fetal to maternal ratios for individual PCB congeners, DDT compounds, and ΣPCBs, ΣDDTs, and ΣPCB TEQs were lower among premature compared with late-term fetuses. These ratios increased for both groups as the logarithmic n-octanol/water partition coefficient (log Kow) for each compound decreased. Linear predictions for ΣPCB and ΣDDT concentrations in fetal blubber could be obtained using the ΣPCB and ΣDDT concentrations in maternal blubber, maternal and fetal blubber lipid content, maternal mass, and maternal age. Fetal TEQ was explained by maternal TEQ and maternal age. The ability to predict contaminant concentrations in fetal blubber from maternal parameters is important for developing risk assessment models for marine mammals.
Marine sediment toxicity identification evaluation methods for the anionic metals arsenic and chromium
Authors: Burgess Robert M. , Perron Monique M. , Cantwell Mark G. , Ho Kay T. , Pelletier Marguerite C. , Serbst Jonathan R. , Ryba Stephan A. 
Published: December 2006

AbstractMarine sediments accumulate a variety of contaminants and, in some cases, demonstrate toxicity because of this contamination. Toxicity identification evaluation (TIE) methods provide tools for identifying the toxic chemicals causing sediment toxicity. Currently, whole-sediment TIE methods are not available for anionic metals like arsenic and chromium. In the present paper, we describe two new anion-exchange resins used in the development of whole-sediment TIE methods for arsenic and chromium. Resins were shown to reduce whole-sediment toxicity and overlying water concentrations of the anionic metals. Sediment toxicity, expressed as the median lethal concentration, was reduced by a factor of two to a factor of nearly six between amended sediment treatments containing resin and those without resin. Aqueous concentrations of arsenic and chromium in the toxicity exposures decreased to less than the detection limits or to concentrations much lower than those measured in treatments without resin. Interference studies indicated that the anion-exchange resins had no significant effect on concentrations of the representativepesticide endosulfan and minimal effects on concentrations of ammonia. However, the anion-exchange resins did significantly reduce the concentrations of a selection of cationic metals (Cd, Cu, Ni, Pb, and Zn). These data demonstrate the utility of anion-exchange resins for determining the contribution of arsenic and chromium to whole-sediment toxicity. The present results also indicate the importance of using TIE methods in a formal TIE structure to ensure that results are not misinterpreted. These methods should be useful in the performance of marine whole-sediment TIEs.
An integrated model describing the toxic responses ofDaphnia magnato pulsed exposures of three metals
Authors: Hoang Tham C. , Tomasso Joseph R. , Klaine Stephen J. 
Published: December 2006

AbstractSome toxicology research in which toxicant exposures are continual (pulsed) rather than continuous have been reported. A number of toxicity models have been developed for pulsed and continuous exposures. Most of these models were developed based on one- or two-compartment, first-order toxicokinetics and were calibrated with organic compounds. In the present study, the relationship between mortality (after 21 d) of Daphnia magna in response to pulsed and continuous exposures to Cu, Zn, and Se was used to develop a model that integrated the effects of single and multiple pulsed metal exposures based on first-order uptake and depuration kinetics. Mortality was a function of exposure concentration, duration, and recovery time between exposures. The model was successfully validated using an independent data set. It is applicable to risk assessment and, potentially, may be incorporated with other models (e.g., the biotic ligand model) to predict the toxicity of pulsed metal exposures under a range of environmental conditions.
Risk assessment of Magnacide® H herbicide at Río Colorado irrigation channels (Argentina). tier 3: Studies on native species
Authors: Venturino Andrés , Montagna Cristina Mónica , de D'Angelo Ana María Pechen 
Published: December 2006

Abstract
We evaluated the potential environmental risk of the herbicide Magnacide® (Baker Petrolite, TX, USA) using native species from Argentina, representing the ecosystem at the Irrigation Corporation (CORFO) channels at the Colorado River mouth, Buenos Aires, Argentina. Six species including fish, toads, snails, crustaceans, and insects were selected to perform studies on acute toxicity and repeated exposure effects. Magnacide H susceptibility ranking was Bufo arenarum (lethal concentration 50 [LC50] = 0.023 mg/L), Onchorhynchus mykiss (LC50 = 0.038 mg/L), Heleobia parchappii (LC50 = 0.21 mg/L), Hyalella curvispina (LC50 = 0.24 mg/L), Simulium spp. (LC50 = 0.60 mg/L), and Chironomus spp. (LC50 = 2.83 mg/L). The risk limit of 10th percentile (0.013 mg/L) determined by probit analysis on sensitivity distribution was similar to the one calculated from literature data. Risk assessment based on field application data suggested lethal exposures for more than 70 to 90% of the species up to 20 km downstream from the application point. Repeated exposures to Magnacide H of amphibian larvae at the lowest-observed-effect concentration caused some effects during the first exposure, but without cumulative effects. Amphipods were insensitive to repeated exposures, showing no cumulative effects. Whether short-term exposures may result in long-term sublethal effects on the organism's life history was not addressed by these laboratory tests. In conclusion, tier 3 studies indicate that Magnacide H application schedule is extremely toxic for most native species at CORFO–Río Colorado channels, representing a high potential risk in the environment. The real environmental impact must be addressed by field studies at tier 4 giving more information on population effects and communities.
Environmental effect assessment of Magnacide® H herbicide at Río Colorado irrigation channels (Argentina). tier 4: In situ survey on benthic invertebrates
Authors: Albariño Ricardo , Venturino Andrés , Montagna Cristina Mónica , de D'Angelo Ana María Pechen 
Published: December 2006

Abstract
The objective of this study was to assess the effects of Magnacide® H (Baker Petrolite, TX, USA) usage on the aquatic ecosystem at the Cooperativa de Riego y Fomento (CORFO)–Río Colorado irrigation channels, analyzing the effects on benthic invertebrates. At recommended treatment concentrations, Magnacide H kills most of the aquatic organisms; however, its presence in the channels is transient. Magnacide H caused a significant reduction in the number of taxa (58%), abundance (57%), and community diversity (67%) in the benthic assemblage with respect to untreated channels during the application period in the first year of the study. The herbicide reduced the abundance of the most abundant taxa: oligochaetes, chironomids, ostracods, and the snails Biomphalaria peregrina and Heleobia parchappii. In contrast, the herbicide only reduced invertebrate diversity during the application period at the second year of study. Two months after the applications had ceased, the benthic community in treated channels recovered their biotic attributes, reaching values similar to controls. Recovery could have occurred from upstream unimpaired reaches supplying migrating invertebrates that recolonized affected areas. Since recovery occurred within a reasonable period of time, we conclude that the impact of Magnacide H at CORFO–Río Colorado channels is acceptable from a regulatory point of view in the present practice protocol. Nevertheless, a strict control on the application conditions must be ensured to minimize the risk on the ecological receptors. We emphasize the recommendation that water release outside the channels is prevented until the product has dissipated.
Expression pattern of metallothionein, MTF-1 nuclear translocation, and its dna-binding activity in zebrafish (Danio rerio) induced by zinc and cadmium
Authors: Chen Wen-Ya , John Joseph Abraham Christopher , Lin Cheng-Hui , Chang Chi-Yao 
Published: December 2006

Abstract
Metallothionein is a small (6-kDa), cysteine-rich protein expressed by a six–zinc finger protein called metal-responsive element–binding transcription factor-1 (MTF-1) in response to Zn and Cd. Our previous reports have shown the basal expression of metallothionein (mt) and MTF-1 (mtf-1) genes in embryo and early larval stages of zebrafish (Danio rerio). In the present study, we investigated the mt expression in zebrafish early larvae induced by exposure to Cd and Zn (48, 72, 96, and 120 h postfertilization). Whole-mount in situ hybridization showed that Zn induced mt expression in the olfactory pit, cerebellum, ceratobranchials, liver, chloride cells, and neuromasts of the lateral line. Cadmium also induced mt expression in all the above regions except the cerebellum. Using fluorescence techniques, we have shown that Zn and Cd mediate cytoplasmic and nuclear translocation of MTF-1–enhanced green fluorescent protein fusion protein in zebrafish liver cell line. The MTF-1 protein was produced recombinantly by inserting zebrafish mtf-1 cDNA (1.8 kb) into pET-20b(+) expression vector and expressing in Escherichia coli BL21 (DE3) pLysS host strain competent cell on induction with isopropyl-β-D-thiogalactopyranoside. The protein was then purified by affinity chromatography on a nickel–nitrilotriacetic acid column. Electrophoretic mobility shift assay revealed binding of the recombinant MTF-1 in response to Zn and Cd at the putative metal-responsive elements (MREs) in the promoter region of the mt gene. Taken together, these results suggest that Zn and Cd are efficiently involved with mt expression induced in zebrafish embryos and with MTF-1 nuclear translocation and that this induction is achieved through the activation of MTF-1 binding at the MREs.
Bioaccumulation of the hepatotoxic microcystins in various organs of a freshwater snail from a subtropical Chinese Lake, Taihu Lake, with dense toxic Microcystis blooms
Authors: Zhang Dawen , Xie Ping , Liu Yaqin , Chen Jun , Liang Gaodao 
Published: December 2006

Abstract
In this paper, we describe the seasonal dynamics of three common microcystins (MCs; MC-RR, MC-YR, and MC-LR) in the whole body, hepatopancreas, intestine, gonad, foot, remaining tissue, and offspring of a freshwater snail, Bellamya aeruginosa, from Gonghu Bay of Lake Taihu, China, where dense toxic Microcystis blooms occur in the warm seasons. Microcystins were determined by liquid chromatography electrospray ionization mass spectrum. Microcystin (MC-RR + MC-YR + MC-LR) content of the offspring and gonad showed high positive correlation, indicating that microcystins could transfer from adult females to their young with physiological connection. This study is the first to report the presence of microcystins in the offspring of the adult snail. The majority of the toxins were present in the intestine (53.6%) and hepatopancreas (29.9%), whereas other tissues contained only 16.5%. If intestines are excluded, up to 64.3% of the toxin burden was allocated in the hepatopancreas. The microcystin content in the intestine, hepatopancreas, and gonad were correlated with the biomass of Microcystis and intracellular and extracellular toxins. Of the analyzed foot samples, 18.2% were above the tolerable daily microcystin intake recommended by the World Health Organization (WHO) for human consumption. This result indicates that public health warnings regarding human ingestion of snails from Taihu Lake are warranted. In addition, further studies are needed to evaluate the occurrence by Microcystis in relation to spatial and temporal changes in water quality.
Mercury bioaccumulation in green frog (Rana clamitans) and bullfrog (Rana catesbeiana) tadpoles from Acadia National Park, Maine, USA
Authors: Bank Michael S. , Crocker Jeff , Connery Bruce , Amirbahman Aria 
Published: December 2006

Abstract
Mercury contamination in the northeastern United States, including Acadia National Park (ANP; ME, USA), is well documented and continues to be a public health issue of concern. Mercury contamination of wild amphibians has received little attention, however, despite reports of worldwide population declines. Here, we report total Hg and methyl Hg (MeHg) concentrations for water, sediment, and green frog (Rana clamitans) and bullfrog (Rana catesbeiana) tadpoles (age, approximately one year) from ANP. Total Hg concentrations (mean ± standard error) in green frog and bullfrog tadpoles were 25.1 ± 1.5 and 19.1 ± 0.8 ng/g wet weight, respectively. Mean total Hg was highest for green frog tadpoles sampled from the Schooner Head site (ANP, Bar Harbor, ME, USA), a small, semipermanent beaver pond where Ranavirus was detected during the summer of 2003 sampling period. Methyl Hg comprised 7.6 to 40% of the total Hg in tadpole tissue (wet-wt basis), and mean total Hg levels in tadpoles were significantly different among pond sites (n = 9). Total Hg in pond water was a significant predictor of tadpole total Hg levels. Dissolved organic carbon was a significant predictor of both total Hg and MeHg in water, and total Hg in water also was strongly correlated with MeHg in water. Of the nine pond ecosystems sampled at ANP, 44% had a methylation efficiency (water MeHg to total Hg ratio) of greater than 10%, and 33% had total Hg levels in sediment that were approximately equal to or greater than the established threshold level effect concentration for freshwater sediments (0.174 mg/kg dry wt). Our data indicate that wetland food webs in ANP likely are susceptible to high levels of total Hg bioaccumulation and that methylation dynamics appear to be influenced by local abiotic and biotic factors, including disturbances by beavers and in situ water chemistry patterns. These findings may be important to National Park Service resource managers, especially considering the class I airshed status of ANP and the strong potential for negative effects to aquatic ecosystem structure and function from Hg pollution.
Investigation of a High Temperature Organic Water Shutoff Gel: Reaction Mechanisms
Authors: Al-Muntasheri Ghaithan A. , Nasr-El-Din Hisham A. , Peters Joop , Zitha Pacelli L.J. 
Published: December 2006

Summary
Water production during oil and gas recovery is a longstanding problem that is becoming critical with maturing fields worldwide. Lifting, processing, treating, and reinjection of the unwanted water add to the overall oil production costs. Also, water disposal may pose environmental problems. Recent statistical studies indicate that processing unwanted water costs the oil industry nearly U.S. $40 billion per year.
Polymer gels have been widely used as blocking agents for excessive water production. In this study, two different polymers were crosslinked with polyethyleneimine (PEI). The first is a copolymer of polyacrylamide tert-butyl acrylate (PAtBA), and the second is a polyacrylamide (PAM). The PAtBA/PEI system was previously shown to be stable at temperatures up to 160°C, typical of those encountered in deep oil and gas reservoirs. However, the crosslinking mechanisms of this system at high temperatures have not been well defined.
This study examined the structural changes of PAtBA using C-13 nuclear magnetic resonance (NMR) spectroscopy. Understanding these changes is a first step toward the identification of the crosslinking mechanisms of PAtBA and PAM with PEI. This will have a strong impact on the design of water shutoff treatments utilizing these systems.

Introduction
As oil and gas fields mature, larger volumes of water are produced. Separating, treating, and disposing this water add extra costs to the petroleum production. It has been reported that the petroleum industry spends several tens of billions of dollars to deal with excessive water production (Bailey et al. 2000).
Hydrophilic polymer gels have been widely used to reduce (Zaitoun and Kohler 1988) or completely block (Hutchins et al. 1996.water from its producing zones. Polyacrylamides have been the most commonly used base polymers crosslinked with either inorganic or organic crosslinkers. Inorganic crosslinkers include Cr+3, Al+3, and Zr+4 and have been mostly utilized to crosslink partially hydrolyzed polyacrylamide (HPAM). Inorganically crosslinked gels result from the ionic bonding between the negatively charged carboxylate groups and the multivalent cation (Prud'homme et al. 1983; Lockhart 1994; te Nijenhuis et al. 2003).
Organic crosslinkers were introduced to obtain gels that are stable over a wider temperature range (Moradi-Araghi 1991; Albonico et al. 1994; Hardy et al. 1999). This is possible because in this case, the crosslinking is done by a covalent bonding, which is much more stable than ionic bonds. The covalent bonds often involve the amide groups on the polymer backbone. A typical example of an organically crosslinked gel is the polyacrylamide-phenol/formaldehyde system, which has been reported to be stable at 121 DEGREE C for 13.3 years (Moradi-Araghi 2000, 1993). However, its toxicity has limited its broad use in the field. Chemical alternatives for the phenol/formaldehyde system were also reported (Moradi-Araghi 1994; Dovan et al. 1997).
Temperature tuning of polarization mode dispersion in single-core and two-core photonic liquid crystal fibers
Authors: Lesiak P. , Woliński T. , Brzdąkiewicz K. , Nowecka K. , Ertman S. , Karpierz M. , Domański A. , Dąbrowski R. 
Published: December 2006

AbstractIn this paper we present numerical and experimental results of propagation and polarization properties of the photonic liquid crystal fibers (PLCFs) in which only selected micro holes were filled with nematic liquid crystal (LC) guest materials. As a host photonic crystal fiber (PCF) structure, we used a commercially available highly birefringent PCF (Blazephotonics, UK). A tunable laser operated at infrared has powered the PLCFs under investigation infiltrated by the 1550 nematic LC synthesized at the Military University of Technology. Temperature induced changes of the polarization mode dispersion (PMD) as well switching between fundamental and higher order modes and also single-core and two-core propagation were successfully demonstrated.
Electrophysical properties of a system with induced antiferroelectric phase comprising cyano compound
Authors: Skrzypek K. , Tykarska M. , Piecek W. 
Published: December 2006

AbstractThe DSC, electrooptic and X-ray results for the system composed of two synclinic compounds CNCH2COO(CH2)6OphPhCOOPhCOOC*H(CH3)C6H13 and C5H11COO(CH2)3OPhCOOPhPhCOOC*H(CH3)C6H13 are presented. The antiferroelectric SmC*A phase induces in this system and it was confirmed by physical measurements. It was found out that the mechanism of SmC*A phase induction is different than in systems comprising compound with perfluoroalkyl chain.
Discovery of transport and reaction properties in distributed systems
Authors: Zhang Libin , Kulkarni Kedar , Somayaji MahadevaBharath R. , Xenos Michalis , Linninger Andreas A. 
Published: December 2006

AbstractIn distributed systems, transport phenomena coupled with chemical or metabolic reactions are functions of space. A computational method is outlined to acquire unknown system properties in distributed systems by problem inversion. Physical and chemical properties are estimated simultaneously. The finite‐volume discretization method formulated in generalized curvilinear coordinates applied to inversion problem of arbitrarily complex geometries. The direct solution approach of the reacting transport problem through inexpensive acquisition of sensitivity information is presented. An inexact trust region method improves the convergence rate of the large‐scale transport and kinetic inversion problem (TKIP). The case studies demonstrate a novel computational approach for quantifying unknown transport properties, as well as reaction or metabolic constants. Solutions to technological challenges is presented in computational fluid mechanics and biotransport using mathematical programming techniques for inversion of distributed systems. © 2006 American Institute of Chemical Engineers AIChE J, 2006
News cues: Information scent and cognitive heuristics
Authors: Sundar S. Shyam , Knobloch‐Westerwick Silvia , Hastall Matthias R. 
Published: December 2006

AbstractGoogle News and other newsbots have automated the process of news selection, providing Internet users with a virtually limitless array of news and public information dynamically culled from thousands of news organizations all over the world. In order to help users cope with the resultant overload of information, news leads are typically accompanied by three cues: (a) the name of the primary source from which the headline and lead were borrowed, (b) the time elapsed since the story broke, and (c) the number of related articles written about this story by other news organizations tracked by the newsbot. This article investigates the psychological significance of these cues by positing that the information scent transmitted by each cue triggers a distinct heuristic (mental shortcut) that tends to influence online users' perceptions of a given news item, with implications for their assessment of the item's relevance to their information needs and interests. A large 2 × 3 × 6 within‐subjects online experiment (N = 523) systematically varied two levels of the source credibility cue, three levels of the upload recency cue and six levels of the number‐of‐related‐articles cue in an effort to investigate their effects upon perceived message credibility, newsworthiness, and likelihood of clicking on the news lead. Results showed evidence for source primacy effect, and some indication of a cue‐cumulation effect when source credibility is low. Findings are discussed in the context of machine and bandwagon heuristics.