bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of polycyclic aromatic hydrocarbon bioavailability in estuarine sediments using thin-film extraction
Authors: Golding Christopher J. , Gobas Frank A.P.C. , Birch Gavin F. 
Published: April 2007

AbstractIt is well documented that the bioavailability of hydrophobic organic chemicals (HOCs) can vary substantially among sediments. This makes risk assessments based on total sediment concentrations problematic. The present study investigates the application of thin-film solid-phase extraction to measure bioavailable concentrations of phenanthrene in estuarine sediment by comparing concentrations of phenanthrene in the amphipod Corophium colo and in thin ethylene/vinyl acetate films at different concentrations in three geochemically different sediments. For all sediment types, concentrations of phenanthrene in sediments and thin films followed linear relationships, indicating first-order exchange kinetics. Organism/thin-film concentration ratios did not vary systematically among sediment types but dropped significantly with increasing phenanthrene concentration in the sediments. While at low phenanthrene concentrations in the sediment fugacities of phenanthrene in the amphipods approached the fugacities in the thin films, they were significantly lower than those in the sediments at higher concentrations. While phenanthrene concentrations in the three sediment types were identical, biota sediment accumulation factors and concentrations in amphipods and thin films were consistently lower in sediments enriched with black carbon than in sediments with sedimentary organic matter bearing a more diagenetic organic signature. It is concluded that, for the range of concentrations tested, thin-film solid-phase extraction can be a useful tool in the characterization of differences in bioavailability of HOCs among sediment types.
Gill metal binding and stress gene transcription in brown trout (Salmo trutta) exposed to metal environments: The effect of pre-exposure in natural populations
Authors: Hansen Bjørn Henrik , Garmo Øyvind A. , Olsvik PÅl A. , Andersen Rolf A. 
Published: April 2007

AbstractBrown trout (Salmo trutta) from two native populations from the Røros area in Central Norway, acclimated in mining-affected habitats to different levels of Cd/Zn and Cu, together with trout from a nearby unaffected river (reference) were transferred to a nearby lake with higher levels of Cu, Cd, and Zn than those in their respective native rivers. This experiment was conducted to gain information about the underlying resistance mechanisms developed in fish exposed to metal environments. The focus was on gill metal accumulation and transcription of the metal-responsive stress genes metallothionein-A (MT-A), Cu/Zn-superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and heat shock protein 70 (HSP-70). The only shared response shown between the three groups after transfer were Cu accumulation and MT-A induction. The Cu-acclimated trout produced mucus to reduce the uptake of Cu into the gills. The MT-A levels were highest in the Cd/Zn-acclimated trout both before and after transfer. Before transfer, antioxidant transcription (SOD and GPx) was higher in gills of Cu-acclimated compared to the Cd/Zn-acclimated trout, but increased transcription of antioxidant stress genes was observed after transfer in both metal-acclimated groups. The metal-acclimated trout groups also showed an increase in the transcription of HSP-70. Compared to the reference population not previously exposed to metals, stress gene transcription increased faster in the metal-acclimated populations. The exception was induction of CAT, which appeared to be depressed after transfer in Cd/Zn-acclimated trout. The data indicate that acclimation to chronic metal exposure involves different strategies to cope with different metals and that these strategies involve both physiological mechanisms (mucus production) as well as metal-related stress gene transcription.
Bioavailability of polycyclic aromatic hydrocarbons sequestered in sediment: Microbial study and model prediction
Authors: Beckles Denise M. , Chen Wei , Hughes Joseph B. 
Published: April 2007

Abstract
In field studies and remediation projects, contaminants persist in soil and sediment much longer than would be estimated based on contaminant physical and chemical properties; such observations indicate that a fraction of contaminants in soil/sediment is much less available to the degrading microorganisms or chemical reagents. Many researchers attribute this reduced availability/bioavailability to the sequestration (also referred to as resistant desorption or desorption hysteresis) of contaminants in soil/sediment. In the present research, desorption and bioavailability of naphthalene, phenanthrene, and fluoranthene were studied to evaluate the impact of sequestration on the biodegradability of these three polycyclic aromatic hydrocarbons (PAHs). Experimental results indicate that only desorbed PAHs are bioavailable and that the bioavailability of sequestered PAHs could be well predicted with a modified bioavailability model, which uses a biphasic desorption model to replace the conventional adsorption/desorption model. Findings in the present study might have important implications for site remediation: After the initial stage of remediation (i.e., after the readily desorbable fraction of contaminants is removed from soil/sediment), desorption of sequestered contaminants becomes the rate-limiting step of remediation. In this stage, the availability of contaminants is so low that even aggressive remediation would have little effect on overall mass reduction. Thus, a more cost-effective approach for site remediation might consist of an initial aggressive treatment followed by plume control, such as monitored natural attenuation.
Soil biogeochemical toxicity end points for sub-Antarctic islands contaminated with petroleum hydrocarbons
Authors: Schafer Alexis Nadine , Snape Ian , Siciliano Steven Douglas 
Published: April 2007

AbstractSub-Antarctic islands have been subjected to petroleum hydrocarbon spills, yet no information is available regarding the toxicity of petroleum hydrocarbons to these subpolar soils. The purpose of the present study was to identify soil biogeochemical toxicity end points for petroleum hydrocarbon contamination in sub-Antarctic soil. Soil from Macquarie Island, a sub-Antarctic island south of Australia, was collected and exposed to 10 concentrations of Special Antarctic Blend (SAB) diesel fuel, ranging from 0 to 50,000 mg fuel/kg soil, for a 21-d period. The sensitivity of nitrification, denitrification, carbohydrate utilization, and total soil respiration to SAB fuel was assessed. Potential nitrification activity was the most sensitive indicator of SAB contamination assessed for nitrogen cycling, with an IC20 (concentration that results in a 20% change from the control response) of 190 mg fuel/kg soil. Potential denitrification activity was not as sensitive to SAB contamination, with an IC20 of 950 mg fuel/kg soil for nitrous oxide production. Nitrous oxide consumption was unaffected by SAB contamination. Carbohydrate utilization (respiration caused by sucrose) was a more sensitive indicator (IC20, 16 mg fuel/kg soil) of SAB contamination than total respiration (IC20, 220 mg fuel/kg soil). However, total soil respiration was a more responsive measurement end point, increasing soil respiration over a 72-h period by 17 mg of CO2, compared to a change of only 2.1 mg of CO2 for carbohydrate utilization. Our results indicate that IC20s varied between 16 to 950 mg fuel/kg soil for Macquarie Island soil spiked with SAB diesel fuel. These results indicate that current cleanup levels derived from temperate zones may be too liberal for soil contamination in sub-Antarctic islands.
Causes of water toxicity toHyalella aztecain the New River, California, USA
Authors: Phillips Bryn M. , Anderson Brian S. , Hunt John W. , Tjeerdema Ron S. , Carpio-Obeso Maria , Connor Valerie 
Published: April 2007

AbstractThe New River (CA, USA) was created in 1905 to 1907 when the Colorado River washed out diversionary works and flowed into the Salton Basin, creating the Salton Sea. Approximately 70% of the river's current flow is agricultural wastewater from the Imperial Valley. The river is contaminated with pesticides, industrial organic chemicals, metals, nutrients, bacteria, and silt. Monitoring for the State of California Surface Water Ambient Monitoring Program has indicated persistent water column toxicity to the epibenthic amphipod Hyalella azteca. Four toxicity identification evaluations (TIEs), along with chemical analyses, were performed, and the results indicated multiple and varying causes of toxicity. The first two TIEs characterized the causes of toxicity as a combination of metals and organics, but only the second sample contained enough total copper to contribute to toxicity. The third TIE used an emerging method for characterizing and identifying toxicity caused by pyrethroid pesticides. This TIE characterized organics as the cause of toxicity, and a carboxylesterase enzyme treatment further identified the cause of toxicity as pyrethroids. The final TIE used the enzyme and Phase II procedures to identify cypermethrin as the cause of toxicity. The TIE results demonstrate the evolving causes of toxicity in the New River and should assist regulators with implementing the total maximum daily load process for pesticides, particularly pyrethroids. Further research will determine if pyrethroids and other New River contaminants are having an impact on the Salton Sea.
The relationship between cholinesterase inhibition and two types of swimming performance in chlorpyrifos-exposed coho salmon (Oncorhynchus kisutch)
Authors: Tierney Keith , Casselman Matt , Takeda Scott , Farrell Tony , Kennedy Chris 
Published: April 2007

AbstractBrain acetylcholinesterase (AChE) activity was evaluated after two different swimming tests in coho salmon (Oncorhynchus kisutch; 238 ± 5 g) given 96-h exposures to 0, 5, 10, 20, or 40 μg/L of chlorpyrifos. Brain AChE activity decreased in a concentration-dependent manner (AChE activities were 81.8, 52.2, 37.3, and 21.3% of control for the 5, 10, 20, and 40 μg/L exposures, respectively), whereas swimming performance was impaired after a threshold of AChE impairment was reached. Specifically, for swimming performance (Ucrit) measured using the established ramp-Ucrit test (duration, 152 ± 8 min), this threshold occurred with AChE activity of 68.5% ± 18.1% of control. For a rapid acceleration test (UΔV, where V represents velocity; 27.6 ± 0.8 min), this value was 52.6% ± 15.4% of control. Both swim protocols resulted in similar maximum swim speeds (control ramp-Ucrit and UΔV values of 3.44 ± 0.09 and 3.71 ± 0.13 body lengths/s, respectively), and performance was significantly reduced after 20 and 40 μg/L exposures in both groups (ramp-Ucrit values: 86.4 and 83.6 %, respectively, of control; UΔV values: 85.2 and 77.8%, rsepectively, of control). Although both tests yielded similar swim speeds, postexercise plasma lactate concentrations were greater for the UΔV test (11.3 ± 0.6 vs 8.6 ± 0.5 mmol/L), indicating a greater anaerobic effort. This increase was exaggerated after 10 μg/L of chlorpyrifos (14.6 ± 1.3 mmol/L), indicating that anaerobic muscle was used to attain the same speed. Given the threshold relationship between AChE inhibition and swimming performance, coho salmon appear able to maintain integrated swimming activity despite significant impairment of an underlying neurological control mechanism.
Environmentally relevant concentrations of ethynylestradiol cause female-biased sex ratios in Xenopus tropicalis and Rana temporaria
Authors: Pettersson Irina , Berg Cecilia 
Published: April 2007

Abstract
The susceptibility of Xenopus (Silurana) tropicalis and Rana temporaria to ethynylestradiol (EE2), a potent estrogenic pharmaceutical and environmental pollutant, was investigated. Larval EE2 exposure caused female-biased sex ratios at concentrations as low as 0.06 nM, which is comparable to levels found in the environment. The susceptibility of the two frog species to EE2 was comparable, supporting the use of X. tropicalis as a model organism for research on developmental reproductive toxicity of estrogenic pollutants.
Developmental toxicity in zebrafish (Danio rerio) embryos after exposure to manufactured nanomaterials: Buckminsterfullerene aggregates (nC60) and fullerol
Authors: Zhu Xiaoshan , Zhu Lin , Li Yan , Duan Zhenghua , Chen Wei , Alvarez Pedro J.J. 
Published: April 2007

Abstract
The present paper summarizes, to our knowledge, the first study regarding the developmental toxicity of stable buck-minsterfullerene aggregates suspended in water (nC60) using zebrafish (Danio rerio) as a vertebrate model. Zebrafish embryo survival, hatching rate, heartbeat, and pericardial edema were noted and described within 96 h of exposure. Fullerol (a hydroxylated C60 derivative, C60(OH)16–18) at 50 mg/L did not exert toxicity to zebrafish embryos. In contrast, nC60 at 1.5 mg/L delayed zebrafish embryo and larval development, decreased survival and hatching rates, and caused pericardial edema. Toxicity was mitigated by adding an antioxidant (glutathione), which suggests that a free radical—induced mechanism or another form of oxidative stress played a role in developmental toxicity.
How the Federal Republic Became an Immigration Country: Norms, Politics and the Failure of West Germany's Guest Worker System
Authors: Triadafilopoulos Triadafilos , Schönwälder Karen 
Published: April 2007

With the passage of a new citizenship law in 1999 and the so-calledZuwanderungsgesetz (Migration Law) of 2004, contemporary Germanyhas gone a long way toward acknowledging its status as an immigrationcountry (Einwanderungsland). Yet, Germany is still regarded bymany as a “reluctant” land of immigration, different than traditionalimmigration countries such as Canada, the United States, and Australia.It owes this image to the fact that many of today’s “immigrants”were in fact “guests,” invited to work in the Federal Republicin the 1950s, 1960s and 1970s and expected to leave when they wereno longer needed. Migration was meant to be a temporary measure,to stoke the engine of the Economic Miracle but not fundamentallyalter German society. The question, then, is how did these “guestworkers” become immigrants? Why did the Federal Republicbecome an immigration country?
A Density Functional Theory Study of the Stille Cross‐Coupling via Associative Transmetalation. The Role of Ligands and Coordinating Solvents
Authors: Faza Rosana Álvarez Olalla Nieto , de Lera Angel R. , Cárdenas Diego J. 
Published: April 2007

AbstractAn associative mechanism has been computationally characterized for the Stille cross‐coupling of vinyl bromide and trimethylvinylstannane catalyzed by PdL2 (L=PMe3, AsMe3) with or without dimethylformamide as coordinating ligand. All the species along the catalytic cycles that start from both the cis‐ and the trans‐PdL(Y)(vinyl)Br complexes (Y=L or S; L=PMe3, AsMe3 or PH3; S=DMF) have been located in the gas phase and in the presence of polar solvents. Computations support the central role of species trans‐PdL(DMF)(vinyl)Br which react by ligand dissociation and stannane coordination in the rate‐limiting transmetalation step via a puckered four‐coordinate (at palladium) transition state comprised of Pd, Br, Sn and sp2 C atoms. A donating solvent may enter the catalytic cycle assisting isomerization of cis‐PdL2(vinyl)Br to trans‐PdL(DMF)(vinyl)Br complexes via a pentacoordinate square pyramidal Pd intermediate. In keeping with experimental observations, the activation energies of the catalytic cycles with arsines as Pd ligands are lower than those with phosphines. Polytopal rearrangements from the three‐coordinate T‐shaped Pd complexes resulting from transmetalation account for the isomerization and the CC bond formation on the reductive elimination step.
Imidazole and Imidazoline Derivatives as N‐Donor Ligands for Palladium‐Catalyzed Mizoroki–Heck Reaction
Authors: Haneda Satoshi , Ueba Chigusa , Eda Kazuo , Hayashi Masahiko 
Published: April 2007

AbstractImidazole and imidazoline (dihydroimidazole) derivatives can serve as efficient and simple ligands for the palladium‐catalyzed Mizoroki–Heck reaction. Among the imidazole and imidazoline derivatives in our investigations, the 2‐methylimidazoline‐palladium(II) chloride complex exhibited the highest catalytic activity.
A Simple Approach to Unsymmetric Atropoisomeric Bipyridine N,N′‐Dioxides and Their Application in Enantioselective Allylation of Aldehydes
Authors: Hrdina Radim , Valterová Irena , Hodačová Jana , Císařová Ivana , Kotora Martin 
Published: April 2007

AbstractThe [2+2+2] cyclotrimerization of 1‐isoquinolinyl‐1,7‐octadiyne with benzonitrile catalyzed by CpCo(CO)2 opened a new pathway for a synthesis of unsymmetrical axially chiral bipyridine N,N′‐dioxides. The N,N′‐dioxide 3a was found to be highly catalytically active and enantioselective for the asymmetric allylation of aldehydes with allyltrichlorosilane. The allylation took place with even 1 % of the catalyst with an enantioselectivity up to 87 % ee.
An Efficient Rhodium‐Catalyzed Double Hydroaminocarbonylation of Alkynes with Carbon Monoxide and Amines Affording 1,4‐Diamide Derivatives
Authors: Huang Qiufeng , Hua Ruimao 
Published: April 2007

AbstractThe hydroaminocarbonylation of terminal alkynes with carbon monoxide and pyrrolidine or piperidine catalyzed by rhodium complexes affords 1,4‐diamide derivatives in good to high yields.
Towards a Greener Epoxidation Method: Use of Water‐Surfactant Media and Catalyst Recycling in the Platinum‐Catalyzed Asymmetric Epoxidation of Terminal Alkenes with Hydrogen Peroxide
Authors: Colladon Marco , Scarso Alessandro , Strukul Giorgio 
Published: April 2007

AbstractRemarkable improvements in enantioselectivity as well as recycle were observed in the catalytic asymmetric epoxidation of terminal alkenes with a chiral, electron‐poor platinum(II) catalyst with hydrogen peroxide as terminal oxidant in water‐surfactant media.
Hydrogen sulfide poisonings in hot‐spring reservoir cleaning: Two case reports
Authors: Deng Jou‐Fang , Chang Shi‐Chuan 
Published: April 2007

AbstractThe potential hazards to maintenance personnel cleaning hot‐spring reservoirs are reported following two severe and unusual episodes of acute hydrogen sulfide poisoning involving seven workers. In the first episode, five victims lost consciousness immediately after climbing down a manhole to the bottom of a reservoir disregarding a strong odor of rotten eggs. One of them died immediately. Of the four who lived, three developed hemorrhagic keratoconjunctivitis and aspiration pneumonia, but no sequelae were observed 2 years later. In the second episode, two workers had been cleaning the reservoir for about 2 hours when one collapsed and his companion went to seek help. Both died of acute respiratory distress syndrome due to pulmonary edema within 12 hours. Since hot‐spring bathing is a popular recreation in Taiwan, other accidents of hydrogen sulfide poisoning may have occurred but have not been reported. Such clinical information is helpful to enable regulators to initiate proper precautions to safeguard those workers involved.
Hippuric acid and ortho‐cresol as biological indicators of occupational exposure to toluene
Authors: de Rosa E. , Bartolucci G. B. , Sigon M. , Callegaro R. , Perbellini L. , Brugnone F. 
Published: April 2007

AbstractIndustrial exposure to toluene was studied in a group of 18 subjects working in a printing plant, exposed only to this solvent. Environmental monitoring was carried out using personal samplers for the whole work‐shift. Urine samples were collected for the determination of hippuric acid and ortho(o)‐cresol before toluene exposure, at the end of the work‐shift, and 5, 9, and 17 h after the end of the work‐shift. The values of two metabolites in all the urinary samples were corrected for g creatinine and specific gravity (1.024).Toluene time weighted average (TWA) concentrations ranged from 51 to 221 mg/m3 (7‐h samples; two samplings lasting 3.5 h each). Urinary hippuric acid and o‐cresol values at the end of the work‐shift were significantly higher than the prework‐shift values.Both hippuricuria and o‐cresoluria end‐of‐work‐shift values, corrected for creatinine and specific gravity, were significantly related to the mean daily environmental concentration of toluene, the correlation being weaker for o‐cresol. Correlation coefficients were 0.88 and 0.84 for hippuric acid and 0.63 and 0.62 for o‐cresol after correction for creatinine and specific gravity, respectively. No significant relationship was observed between environmental exposure and the values of the two urinary metabolites 5, 9, and 17 h after the end of the work‐shift.Extrapolated values from the linear regression analysis at 375 mg/m3 were in good agreement with the biological exposure index (BEI) suggested by ACGIH for hippuric acid.We conclude that determination of hippuric acid in urine samples collected at the end of the work‐shift can be used for routine biological monitoring of exposure to toluene, even at low levels. O‐cresol seems to be a less reliable indicator of toluene exposure.
Respiratory effects and dust exposures in hog confinement farming
Authors: Holness D. Linn , O'Blenis E. Lee , Sass‐Kortsak Andrea , Pilger Charles , Nethercott James R. 
Published: April 2007

AbstractFifty‐three hog confinement farmers and 43 control farmers were studied. Pulmonary function, total and respirable personal dust levels, and responses to a health status questionnaire were obtained for all farmers.The hog farmers' total and respirable personal dust exposures were significantly higher than the respective levels of the control farmers. Higher dust levels were associated with the use of floor (scatter) feeding, indoor feed grinding, and the use of high moisture corn feed.Pork producers reported respiratory symptoms significantly more often than controls. Lung function did not differ between the two groups of farmers, nor could dust exposure levels be related to lung function.
Increased chromium and nickel content in lung tissue and bronchial carcinoma
Authors: Kollmeier Heinrich , Seemann Jörg W. , Müller Klaus‐Michael , Rothe Günter , Wittig Peter , Schejbal Vladimir B. 
Published: April 2007

AbstractIn 25 random autopsies, chromium (Cr) and nickel (Ni) in lung tissue and regional lymph nodes were analysed by means of flameless atomic absorption spectrometry (AAS). The subjects originate from Bochum in the Ruhr District, which is defined as a particular pollution area with locally high Cr and Ni emissions. The subjects examined from Bochum (BO) and vicinity have Cr and Ni concentrations about 5 and 6 times higher than those in a previous series form Münster (MS) and vicinity (outside the particular pollution area), which is used for comparison purposes. BO and MS data showed an age‐dependent increase of chromium and nickel in the lung, and in both data sets as well as in the combined, the Cr and Ni values showed extremely high correlations (r > 0.9). The Cr and Ni concentrations (BO) in lung (3.47 ± 2.53 μg Cr/g, 1.09 ± 1.43 μg Ni/g dry weight) and lymph node tissue (6.30 ± 3.72 μg Cr/g, 1.00 ± 0.58 μg Ni/g dry weight) do not show any correlation. The BO data contained four cases of bronchial carcinoma (all male), three of which showed pulmonary Cr and Ni concentrations that lie clearly above the predicted level. One case of bronchial carcinoma had extremely high Cr and Ni values; an occupational exposure as dental laboratory technician is taken into consideration.