bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Case Management Quality Questionnaire
Authors: Hadjistavropoulos Heather D. , Sagan Mark , Bierlein Cecily , Lawson Karen
Published: January 2005

This study documents the development of a new tool to measure the quality of community case management for elderly clients. Information obtained from literature review, client focus groups, and pilot surveys with clients served as the basis for the development of a Case Management Quality Questionnaire (CMQQ). This measure, along with satisfaction, health status, and demographic questions, was administered to 174 home care clients and 78 family members of long term care residents for evaluation of case management services that clients had received in the last 2 to 6 months. Principal components analysis with oblique (Oblimin) rotation identified three subscales of the CMQQ: (1) accessibility, (2) efficiency, and (3) assessment/coordination skill. Study findings suggest that the CMQQ is reliable, valid, and of value in understanding satisfaction with case coordination. Based on client feedback and analysis of the results, some future modifications to the measure are worthy of study. Others interested in measuring and improving case management may similarly benefit from the use of the CMQQ.
Effect of Cognitive-Behavioral Treatments for PTSD on Anger
Authors: Cahill Shawn P. , Rauch Sheila A. , Hembree Elizabeth A. , Foa Edna B.
Published: January 2005

We investigated three questions related to anger and the treatment of chronic posttraumatic stress disorder (PTSD), utilizing data from a previously published study of cognitive behavioral therapies (CBTs) with female assault victims (Foa, Dancu, Hembree, Jaycox, Meadows, & Street, 1999). The questions were: (1) Do CBTs targeted at PTSD result in a concomitant reduction in anger?, (2) If so, how do these treatments compare with one another?, And (3) Do high levels of pretreatment anger predict poorer outcome on measures of PTSD symptom severity, depression, and general anxiety? Data from the State-Trait Anger Expression Inventory at pretreatment and posttreatment assessments were available for 67 participants randomly assigned to receive prolonged exposure (PE;n= 19), stress inoculation training (SIT;n= 18), combined treatment (PE/SIT;n= 17), or waitlist control (WL;n= 13). Compared to WL, treatments significantly lowered levels of state-anger. Comparisons among active treatments indicated significantly lower state-anger for SIT compared to PE/SIT, but PE did not differ from SIT or PE/SIT. Treatment gains were maintained at follow-up. Pretreatment state-anger was correlated with posttreatment PTSD symptom severity and depression, but multiple regression analyses revealed that pretreatment state-anger did not predict posttreatment PTSD symptom severity or depression beyond the corresponding pretreatment levels of PTSD and depression. A sub-group analysis compared treated participants with clinically significant pretreatment elevations in state-anger (n= 9) to the remainder of the treated participants (n= 45). No significant difference in state-anger was found between groups at posttreatment. The high state-anger group reported greater anger than the low state-anger group at follow-up, but the high state-anger group remained significantly less angry at follow-up than at pretreatment. Thus, CBTs for PTSD reduced anger and pretreatment anger did not reduce the efficacy of these treatments for PTSD and associated psychopathology.
Multiple Channel Exposure Therapy of PTSD: Impact of Treatment on Functioning and Resources
Authors: Falsetti Sherry A. , Erwin Brigette A. , Resnick Heidi S. , Davis Joanne , Combs-Lane Amy M.
Published: January 2005

Posttraumatic stress disorder (PTSD) is associated with significant impairment in functioning. Although improvement in PTSD symptoms following cognitive-behavioral treatment of PTSD has been demonstrated in numerous studies, improvement in functioning has yet to be fully explored. In addition to measures of PTSD, measures of functioning may help to identify more reliably broad-based change following cognitive-behavioral treatment of PTSD. A few studies have demonstrated short-term improvement in functioning following pharmacotherapy of PTSD. The current study is the first investigation to examine short- and long-term changes in adjustment and resources following cognitive-behavioral treatment of PTSD. Findings from this study suggest that, immediately following Multiple Channel Exposure Therapy (MCET), female trauma victims with PTSD and comorbid panic attacks reported improvement in work, marital, economic, and overall adjustment. In addition, 3 and 6 months following MCET, patients continued to experience improvement in work, marital, economic, parental, and overall adjustment. Future directions and clinical implications are discussed.
Relevance of generic and site-specific species sensitivity distributions in the current risk assessment procedures for copper and zinc
Authors: Bossuyt Bart T. A. , Muyssen Brita T. A. , Janssen Colin R.
Published: January 2005

Species sensitivity distributions (SSD) were constructed using acute toxicity data of various cladoceran species collected in five different aquatic systems. The aim of this research was to study the relative acute cladoceran community sensitivity in different aquatic systems. Current risk assessment procedures are based upon hypothetical communities and do not take into account variation in species composition and tolerance between aquatic communities. Two metals, copper and zinc, were used as model toxicants. To establish comparative sensitivity, a standard medium (International Organization for Standardization [ISO]) was used. The generic SSD (log-normal distribution) based on toxicity data obtained in this standard medium for all species (collected at all sites) resulted in a hazardous concentrations that protects 95% of the species occurring in a (hypothetical) ecosystem (i.e., hazardous concentration protecting 95% of the species of the hypothetical ecosystem [HC5]) of 6.7 μg Cu L−1 (90% confidence limits: 4.2–10.8) and 559 μg Zn L−1 (375–843). This generic SSD was not significantly different from the site-specific SSDs (i.e., constructed with species only occurring at a specific site). Mean community sensitivity (the geometric mean of 48-h 50% effective concentration [EC50] values of species within a community) among sites varied within a factor of 2 (between 17.3 and 23.6 μg Cu L−1 for Cu and between 973 and 1,808 μg Zn L−1 for Zn), and HC5s varied within a factor of 4 for copper (between 4.5 and 17.3 μg Cu L−1) and 7 for zinc (between 194 and 1,341 μg Zn L−1). For copper, the HC50 of our generic SSD was significantly lower than the one based on literature toxicity data of cladoceran species (which were recalculated to the hardness of our standard medium). In contrast, no significant differences were observed between the generic SSD and the literature-based SSD for zinc. It is suggested that the community sensitivity of different cladoceran populations is similar among aquatic systems and is not dependent on the species composition.
Effect of toxic cations on copper rhizotoxicity in wheat seedlings
Authors: Fortunati Paolo , Lombi Enzo , Hamon Rebecca E. , Nolan Annette L. , McLaughlin Mike J.
Published: January 2005

Copper pollution may occur in acidic soils where the low pH leads to release of Al and Mn in soil solution, which could interact with Cu toxicity. Very little information exists regarding the influence of toxic cations on the phytotoxicity of Cu. In this study, we tested the hypothesis that phytotoxicity of Cu2+ may be overestimated in acidic soils due to synergism between Al or Mn and Cu toxicity. Rhizotoxicity of Al, Mn, and Cu to wheat seedlings was studied in well-defined nutrient solutions, with these elements present singly or in combination. Toxicity was expressed on a solution metal-activity basis, with metal activities calculated using GEOCHEM-PC and verified using Donnan dialysis. Of the three ions, Cu2+ was the most rhizotoxic, with activities of Cu2+, Al3+, and Mn2+ resulting in a 25% reduction in root elongation of 0.12, 1.26, and 211 μM, respectively. Although there was no interaction between Mn2+ and Cu2+ toxicity, Cu2+ was significantly less toxic on a relative basis in the presence of Al3+. Thus, critical thresholds for soil solution Cu2+ activity determined in acidic soils will be underprotective compared to soils that contain low concentrations of soluble Al (e.g., limed or nonacidic soils).
Hormetic effects of gamma radiation on the stress axis of natural populations of meadow voles (Microtus pennsylvanicus)
Authors: Boonstra Rudy , Manzon Richard G. , Mihok Steve , Helson Julie E.
Published: January 2005

We tested the hypothesis that low doses of gamma radiation have beneficial, hormetic effects on the stress axis (the hypothalamic-pituitary-adrenocortical axis) of free-ranging meadow vole populations (Microtus pennsylvanicus). Voles were exposed to chronic gamma radiation from a 137Cs field irradiator. In isolated populations, voles received one of three treatments over a four-year period: Controls (0.19–0.42 μGy/h — levels that were 2–5X above background levels [0.1 μGy/h] and live-trapped in all years — 1982–1985), low doses (22.6 μGy/h — 50–200X background, live-trapped from November 1982–April 1985), or high doses (3,840 μGy/h — 40,000X background, live-trapped from November 1983–April 1985). Voles exposed to a low dose had levels of free and total corticosterone that were significantly higher than those in the control or high-dose groups. Differences in response to radiation between the sexes were apparent for maximum corticosterone-binding capacity, with females exposed to low doses having higher binding capacity than control or high-dose females, whereas males exposed to low doses had lower binding capacity than control or high-dose males. Low-dose voles had higher counts of neutrophils than either the controls or high-dose voles; hematocrit was greater in the controls than in irradiated voles. These results indicate that voles display a hormetic response to radiation, wherein low doses of an otherwise harmful agent produce a beneficial effect. The stimulation of the stress axis resulting in the increased secretion of glucocorticoids, which may protect against the excessive actions of the immune and inflammatory responses, may be a key mechanism producing this effect.
Bioconcentration and elimination of avermectin B1 in sturgeon
Authors: Shen Jlanzhong , Zhang Qidi , Ding Shuangyang , Zhang Suxia , Coats Joel R.
Published: January 2005

The bioconcentration and elimination of avermectin B1 in sturgeon muscle were investigated with high-performance liquid chromatography. Mean concentrations of 0.2 and 1 ng·ml−1 in water were maintained for a 22-d exposure period. The concentrations of avermectin B1α in muscle tissues reached steady state within 14 to 18 d. The level of avermectin B1 concentrations in the fish muscles was 7.75 ± 0.88 and 38.29 ± 1.65 ng·g−1 for the low and high concentrations, respectively, on day 22. The half-life (t1/2) of the concentrations for the two treated groups was 4.95 and 4.33 d for the low and high concentrations, respectively. Greater than 95% of the tissue concentrations were eliminated from the exposed fish after the 14- and 18-d elimination periods. The estimated values of the bioconcentration factor were 42 L/kg for the low-concentration group and 41 L/kg for high-concentration group, and these values were not significantly different (α = 0.05). Avermectin B1α does not strongly bioconcentrate in individual aquatic organism and would not be expected to biomagnify in the food chain.
Hepatic porphyria induced by the herbicide tralkoxydim in small mammals is species-specific
Authors: Pauli Bruce D. , Kennedy Sean W.
Published: January 2005

Tralkoxydim is the active ingredient in a postemergent herbicide used in cereal crops. During preregistration trials, tralkoxydim was observed to cause hepatic porphyria and cholestasis in laboratory mice. Porphyria was not seen in similarly exposed rats or hamsters, but data were not collected regarding the susceptibility of any wild small mammal species to the tralkoxydim-induced porphyria. To address this data gap, we exposed small mammals to tralkoxydim, to 3,5-diethoxycarbonyl-1,4-dihydrocol-lidine (DDC; a known porphyrinogenic chemical), or to sunflower oil alone. We studied small mammal species that might be exposed following agricultural applications of the herbicide, including the white-footed mouse (Peromyscus leucopus), the deer mouse (P. maniculatus), and the meadow vole (Microtus pennsylvanicus). Because of their known susceptibility to both tralkoxydim-and DDC-induced porphyria, commercially supplied Mus musculus (CD-1 Swiss mice) were exposed as positive-control animals. We also exposed offspring of wild-caught M. musculus to compare their responses to those of the commercially supplied animals. Potential hepatotoxicity was determined by assessing the accumulation of liver protoporphyrin. Of the species tested, only M. musculus was susceptible to the porphyrinogenic action of tralkoxydim, and no significant accumulation of protoporphyrin was observed in any of the other species exposed to the herbicide.
Impact of oil-sands based wetlands on the growth of mallard (Anas platyrhynchos) ducklings
Authors: Gurney Kirsty E. , Williams Tony D. , Smits Judit E. , Wayland Mark , Trudeau Suzanne , Bendell-Young Leah I.
Published: January 2005

Identifying the potential effects of industrially formed wetlands on waterfowl populations is important for assessing the suitability of such wetlands in industrial reclamation strategies. Mallard ducklings were held in situ on two industrially formed wetlands and one reference wetland in northern Alberta, Canada. Duckling mass and skeletal size were measured at regular intervals over 33 d, and blood was collected to investigate the analysis of plasma metabolites (triglyceride and glycerol) as an indicator of physiological condition. In repeated-measures analysis of variance (ANOVA), multivariate ANOVA, and subsequent multiple-comparisons tests, body mass and skeletal size were significantly lower in ducklings maintained on the industrial wetland after 2, 5, 9, and 13 d of exposure. In this situation, plasma metabolite analysis did not provide additional information on mass-independent condition. We conclude that if the observed differences in growth and size translate into a decreased survival of juvenile waterfowl inhabiting these wetlands, then populations of these birds in the area could be negatively affected. We emphasize the importance of field-based ecological research in toxicological studies of wildlife.
Feathers as a nondestructive biomonitor for persistent organic pollutants
Authors: Dauwe Tom , Jaspers Veerle , Covaci Adrian , Schepens Paul , Eens Marcel
Published: January 2005

Keratinous tissues of mammals and humans, such as hair, have been used to determine the exposure to polychlorinated biphenyls (PCBs) and organochlorine pesticides. In the present study, we investigated the accumulation of persistent organic pollutants (POPs; PCBs,p,p′-DDT,p,p′-dichlorodiphenyldichloroethane [DDD],p,p′-dichlorodiphenyldichloroethylene [DDE], hex-achlorobenzene [HCB], oxychlordane, trans-nonachlor, polybrominated diphenyl ethers, and polybrominated biphenyls [PBBs]) in feathers of the great tit (Parus major). The accumulation of POPs in feathers and fat samples of 27 adult great tits collected in April 2000 and December 2002 was compared with regard to possible temporal and spatial differences. Polybrominated diphenyl ethers, PBBs, trans-nonachlor, and HCB could not be quantified in feathers. Most PCB congeners and DDTs (p,p′-DDE, p,p′-DDD, and p,p′-DDT) could be determined in feathers, although concentrations in feathers were markedly lower (∑PCB concentration range, 28.2–87.1 ng/g) than concentrations in fat (∑PCB concentration range, 1244–10074 ng/g). Feathers had relatively higher levels of low-chlorinated PCBs (tetra- and pentachlorinated biphenyls) and p,p′-DDD compared to levels in fat, presumably reflecting levels in blood. Persistent organic pollutant concentrations did not increase with the age of the feather, suggesting that exogenous or aerial depositions of POPs onto the feather surface had no, or only minimal, influence on levels in feathers. For almost all compounds studied, POPs in feathers and fat were significantly positively correlated in samples collected during the breeding season but not in samples collected during the winter. This temporal difference may have been caused by seasonal changes in lipid reserves. Although further research is required, feathers appear to be a promising new, nondestructive biomonitor for PCBs and DDTs in avian wildlife.
Brominated flame retardants: Activities in a crustacean development test and in an ecdysteroid screening assay
Authors: Wollenberger Leah , Dinan Laurence , Breitholtz Magnus
Published: January 2005

Brominated flame retardants(BFRs) wereinvestigated for toxic effects both in vivo and in vitro in two invertebrate bioassays. Subchronic effects of tetrabromobisphenol A (TBBPA), tribromophenol (TBP), and four polybrominated diphenyl ethers ([PBDEs]; BDE-28, BDE-47, BDE-99, and BDE-100) on larval development of the marine copepod Acartia tonsa were studied. For TBBPA and TBP 5-d effective median concentration (EC50) values for inhibition of the larval development rate were 125 and 810 μg/L, respectively, whereas the PBDEs were much more potent with 5-d EC50 in the low μg/L range (1.2 μg/L for BDE-100; 4.2 μg/L for BDE-99; 13 μg/L for BDE-28; and 13 μg/L for BDE-47). These concentrations were up to two orders of magnitude below the 48-h LC50 for acute adult toxicity (108 μg/L for BDE-28; 400 μg/L for TBBPA; 520 μg/L for BDE-100; 705 μg/L for BDE-99; 1,500 μg/L for TBP; and 2,370 μg/L for BDE-47). To distinguish between general toxicological and endocrine-mediated toxic effects, the BFRs were assessed in vitro for ecdysteroid agonistic/antagonistic activity with the ecdysteroid-responsive Drosophila melanogaster BII-cell line. The pentabrominated diphenyl ethers BDE-99 and BDE-100 showed weak ecdysteroid antagonistic activity. Thus, these PBDEs may be regarded as potential endocrine disrupters in invertebrates. The combination of in vitro assays and subchronic biotests with ecologically important crustacean species is a rapid and cost-effective tool when screening for sublethal effects of BFRs and other chemicals.
Black-bellied whistling duck (Dendrocygna autumnalis) brain cholinesterase characterization and diagnosis of anticholinesterase pesticide exposure in wild populations from Mexico
Authors: Osten Jaime Rendón-von , Soares Amadeu M. V. M. , Guilhermino Lucia
Published: January 2005

Rice is the main crop in the subbasin of the fluvial lagoon system of Palizada River (FLSPR) in the state of Campeche, Mexico. The pesticides used to control pests of this crop mainly are carbofuran, chlorpyrifos, and glyphosate. Black-bellied whistling duck (Dendrocygna autumnalis) is an ecologically and economically important species in the area. This duck is consumed by local inhabitants throughout the year, despite its potential exposure to pesticides. Due to its feeding habits, abundance, and nutritional value, D. autumnalis is a good indicator of environmental contamination and a potential route of human exposure to organophosphate and carbamate pesticides. In this study, the brain cholinesterase (ChE) in the frontal cerebral cortex of autochthonous ducks was characterized. In addition, the potential of the three locally used pesticides and mixtures to inhibit ChE activity was investigated and the exposure of the wild duck population during intensive pesticide applications in rice fields was evaluated. We found that acetylcholinesterase (AChE) seems to be the predominant ChE form in the biological fraction analyzed. Carbofuran was the most potent ChE inhibitor of D. autumnalis brain ChE activity from the three pesticides analyzed. Cholinesterase inhibition after exposure to pesticide mixtures predominantly was due to carbofuran. A decrease (p < 0.05) in AChE activity (>30%) was apparent in wild ducks compared to reference ducks, with recovery of ChE inhibition in wild ducks occurring months later when no pesticides were applied in the field. Dendrocygna autumnalis brain ChE is a suitable parameter for inclusion in biomonitoring programs for both environmental protection and human safety.
A comparison between the multimedia fate and exposure models caltox and uniform system for evaluation of substances adapted for life-cycle assessment based on the population intake fraction of toxic pollutants
Authors: Huijbregts Mark A. J. , Geelen Loes M. J. , Hertwich Edgar G. , McKone Thomas E. , van de Meent Dik
Published: January 2005

In life-cycle assessment (LCA) and comparative risk assessment, potential human exposure to toxic pollutants can be expressed as the population intake fraction (iF), which represents the fraction of the quantity emitted that enters the human population. To assess the influence of model differences in the calculation of the population iF, ingestion and inhalation iFs of 365 substances emitted to air, freshwater, and soil were calculated with two commonly applied multimedia fate and exposure models, CalTOX and the uniform system for evaluation of substances adapted for life-cycle assessment (USES-LCA). The model comparison showed that differences in the iFs due to model choices were the lowest after emission to air and the highest after emission to soil. Inhalation iFs were more sensitive to model differences compared to ingestion iFs. The choice for a continental seawater compartment, vertical stratification of the soil compartment, rain and no-rain scenarios, and drinking water purification mainly clarify the relevant model differences found in population iFs. Furthermore, pH correction of chemical properties and aerosol-associated deposition on plants appeared to be important for dissociative organics and metals emitted to air, respectively. Finally, it was found that quantitative structure–activity relationship estimates for superhydrophobics may introduce considerable uncertainty in the calculation of population intake fractions.
Relationship between ethinylestradiol-mediated changes in endocrine function and reproductive impairment in Japanese medaka (Oryzias latipes)
Authors: Tilton Susan C. , Foran Christy M. , Benson William H.
Published: January 2005

Many biochemical endpoints currently areused to describe endocrine function in fish; however, the sensitivity of these parameters as biomarkers of impaired reproduction or sexual development is not well understood. In the present study, adult Japanese medaka (Oryzias latipes) were assessed for reproductive output and endocrine function, including circulating steroid concentrations, ex vivo steroidogenesis from the gonads, aromatase activity, hepatic estrogen receptor (ER), and plasma vitellogenin (VTG) after exposure to 0, 0.2, 5, 500, and 2,000 ng/L of 17α-ethinylestradiol (EE) for 14 d. The EE altered these biochemical responses at various sites along the hypothalamus-pituitary-gonadal axis at concentrations as low as 0.2 ng/L, but it only depressed reproductive function at concentrations of 500 ng/L or greater. Offspring also had reduced ability to hatch at 500 ng/L of EE, but this concentration did not produce any other observed changes in development or sexual phenotype. The reproductive parameters correlated well with VTG, ER, and gonadosomatic index (GSI) in both sexes of adult medaka, which could be indicative of the ER-mediated mode of action for EE. Vitellogenin and ER were elevated at higher concentrations of EE in both sexes, whereas GSI was decreased. Overall, most biochemical endpoints were more sensitive than reproduction or development to exposure, indicating that reproductive function may be relatively protected.
Whole-carcass residues of the rodenticide difenacoum in anticoagulant-resistant and -susceptible rat strains (Rattus norvegicus)
Authors: Atterby Helen , Kerins Gerard M. , MacNicoll Alan D.
Published: January 2005

The present study investigated the whole-carcass residue carried by resistant and susceptible laboratory rat strains following 5, 10, or 20 d of feeding on a diet of 25 mg difenacoum/kg bait. The mean whole-carcass residue of difenacoum was determined by high-performance liquid chromatography to be between 0.52 and 0.74 mg/kg body weight in all three rat strains tested. These values were considerably lower than some comparable data previously reported for other species and second-generation rodenticides as well as from mathematical models. The whole-carcass residue of extractable (i.e., nonrefractory) parent compound carried by highly resistant rats fed for 20 d (0.74 mg/kg body wt) is unlikely to present a significantly increased risk to predators compared to the amount carried by susceptible rats after 5 d of feeding (0.52 mg/kg body wt). However, resistant rats are more likely to be available for predation and to be carrying a whole-carcass residue of anticoagulant throughout the duration of a control program.
Insecticide species sensitivity distributions: Importance of test species selection and relevance to aquatic ecosystems
Authors: Maltby Lorraine , Blake Naomi , Brock Theo C. M. , Van den Brink Paul J.
Published: January 2005

Single-species acute toxicity data and (micro)mesocosm data were collated for 16 insecticides. These data were used to investigate the importance of test-species selection in constructing species sensitivity distributions (SSDs) and the ability of estimated hazardous concentrations (HCs) to protect freshwater aquatic ecosystems. A log-normal model was fitted to a minimum of six data points, and the resulting distribution was used to estimate lower (95% confidence), median (50% confidence), and upper (5% confidence) 5% HC (HC5) values. Species sensitivity distributions for specific taxonomic groups (vertebrates, arthropods, nonarthropod invertebrates), habitats (saltwater, freshwater, lentic, lotic), and geographical regions (Palaearctic, Nearctic, temperate, tropical) were compared. The taxonomic composition of the species assemblage used to construct the SSD does have a significant influence on the assessment of hazard, but the habitat and geographical distribution of the species do not. Moreover, SSDs constructed using species recommended in test guidelines did not differ significantly from those constructed using nonrecommended species. Hazardous concentrations estimated using laboratory-derived acute toxicity data for freshwater arthropods (i.e., the most sensitive taxonomic group) were compared to the response of freshwater ecosystems exposed to insecticides. The sensitivity distributions of freshwater arthropods were similar for both field and laboratory exposure, and the lower HC5 (95% protection with 95% confidence) estimate was protective of adverse ecological effects in freshwater ecosystems. The corresponding median HC5 (95% protection level with 50% confidence) was generally protective of single applications of insecticide but not of continuous or multiple applications. In the latter cases, a safety factor of at least five should be applied to the median HC5.
Behavioral responses to sublethal cadmium exposure within an experimental aquatic food web
Authors: Riddell David J. , Culp Joseph M. , Baird Donald J.
Published: January 2005

The foraging and predator-avoidance behaviors of mayfly (Baetis tricaudatus) nymphs and predator-prey interactions were investigated under differing combinations of cadmium concentration and predation risk. Predators consisted of stonefly (Kogotus nonus) nymphs, juvenile brook trout (Salvelinus fontinalis), and longnose dace (Rhinichthys cataractae), either alone or in combination. Organisms were exposed to 0, 0.5, or 5.0 μg/L Cd for 7 d (invertebrates) or 30 d (vertebrates) prior to observation in artificial stream channels. Behavioral observations (20-min duration) were made both day and night over a 24-h period. Mayfly feeding rate was assessed by image analysis of grazed diatom mats cultured on ceramic tiles. Both predators and cadmium produced significant effects on the behavior of B. tricaudatus and K. nonus nymphs, with mayflies showing a hierarchical response in the presence of multiple predators. A significant increase in activity was observed in S. fontinalis exposed to 5.0 μg/L Cd, with significant decreases in capture efficiency of prey items apparent at 0.5 μg/L Cd. Conversely, the foraging behavior of R. cataractae was unaffected by cadmium, possibly as a result of species-specific cadmium tolerance. Such sublethal effects of a contaminant on the energy budgets of individuals and the interactions between species have implications for community structure in aquatic food webs.
Use of laboratory toxicity tests with bivalve and echinoderm embryos to evaluate the bioavailability of copper in San Diego Bay, California, USA
Authors: Rosen Gunther , Rivera-Duarte Ignacio , Kear-Padilla Lora , Chadwick D. Bart
Published: January 2005

Copper concentrations in parts of San Diego Bay (CA, USA) exceed ambient water quality criteria (WQC; currently 3.1 μg/L dissolved, U.S. Environmental Protection Agency [U.S. EPA]). In order to better understand the bioavailability of copper to water-column organisms in the bay, toxicity tests were performed with copper added to surface water collected from various sites in the estuary over a three-year period. The species and endpoints used, bivalve and echinoderm embryo-larval development, are among the most sensitive in the U.S. EPA's national toxicity dataset, which is used to derive WQC. No toxicity was observed in ambient bay water samples, as indicated by high proportions of normally developed larvae in control treatments, averaging 93 ± 5% across all sites and all sampling events. Median effects concentrations (EC50), obtained by copper spiking of ambient water samples, ranged from 1.7 to 3.4 times lower at sites located near the mouth compared to sites near the back of the bay. These data indicate a gradient in complexation capacity increasing from the mouth to the back of the bay, which is consistent with similar trends in dissolved organic carbon and total suspended solids. For the bay as a whole, estimates for total recoverable and dissolved water-effect ratios (WER) ranged from 2.07 to 2.27 and 1.54 to 1.67, respectively. Water-effect ratios of this magnitude suggest that adoption of a somewhat higher site-specific WQC for San Diego Bay still would achieve the level of protection that is intended by the WQC guidelines.
Detection and evaluation of endocrine-disruption activity in water samples from Portuguese rivers
Authors: Quirós Laia , Céspedes Raquel , Lacorte Silvia , Viana Paula , Raldúa Demetrio , Barcelò Damià , Piña Benjamin
Published: January 2005

Water samples (n = 183) from Portuguese rivers were tested for the presence of endocrine disruptors using the recombinant yeast assay (RYA) combined with chemical identification of compounds having endocrine-disruption properties by liquid chromatography coupled to mass spectrometry. Ten selected locations were sampled monthly for a period of 20 months, from April 2001 to December 2002. More than 90% of samples showed either no detectable or low levels of estrogenicity (<0.1 ng/L of estradiol equivalents). The remaining samples (17 in total, 9.3%) showed estrogenicity values ranging from 0.1 to 1.7 ng/L of estradiol equivalents; only two samples showed values greater than 1 ng/L of estradiol equivalents. Most highly estrogenic samples (13 of 17 samples) originated in five sampling sites clustered in two zones near Porto and Lisbon. Chemical analysis detected alkylphenolic compounds (octyl- and nonylphenol plus nonylphenol ethoxylates) in all samples, albeit at concentrations less than 1 μg/L for each compound in 80% of samples. Total analyte concentration exceeded 10 μg/L in only 10 samples, with all but one of those originating from only two sampling sites. In these two locations, a good correlation was observed between the concentrations of octylphenol, nonylphenol, and to a lesser extent, bisphenol A in the samples and their estrogenicity values as calculated by RYA. We conclude that estrogenic activity can be explained by alkylphenol contamination in only these sites; for the remainder, we propose that pesticides and urban waste may be the main factors responsible for estrogenic contamination.
Mode of action and aquatic exposure thresholds of no concern
Authors: de Wolf Watze , Siebel-Sauer Angela , Lecloux Andre , Koch Volker , Holt Martin , Feijtel Tom , Comber Mike , Boeije Geert
Published: January 2005

Threshold concepts of toxicological concern are based on the possibility of establishing an exposure threshold value for chemicals below which no significant risk is to be expected. The objective of the present study is to address environmental thresholds of no toxicological concern for freshwater systems (ETNCaq) for organic chemicals. We analyzed environmental toxicological databases (acute and chronic endpoints) and substance hazard assessments. Lowest numbers and 95th-percentile values were derived using data stratification based on mode of action (MOA; 1 = inert chemicals; 2 = less inert chemicals; 3 = reactive chemicals; 4 = specifically acting chemicals). The ETNCaq values were derived by multiplying the lowest 95th percentile values with appropriate application factors; ETNCaq,MOA1–3 is approximately 0.1 μg/L. A preliminary analysis with complete MOA stratification of the databases shows that in the case of MOA1 or MOA2, the ETNCaq value could be even higher than 0.1 μg/L. A significantly lower ETNCaqMOA4 value was observed based on the long-term toxicity information in the European Centre for the Ecotoxicology and Toxicology of Chemicals database. Application of the ETNCaq value in a tiered risk-assessment scheme may help chemical producers to set data-generation priorities and to refine or reduce animal use. It also may help to inform downstream users concerning the relative risk associated with their specific uses and be of value in putting environmental monitoring data into a risk-assessment perspective.
Toxicity of fluoroquinolone antibiotics to aquatic organisms
Authors: Robinson April A. , Belden Jason B. , Lydy Michael J.
Published: January 2005

Toxicity tests were performed with seven fluoroquinolone antibiotics, ciprofloxacin, lomefloxacin, ofloxacin, levofloxacin, clinafloxacin, enrofloxacin, and flumequine, on five aquatic organisms. Overall toxicity values ranged from 7.9 to 23,000 μg/L. The cyanobacterium Microcystis aeruginosa was the most sensitive organism (5-d growth and reproduction, effective concentrations [EC50s] ranging from 7.9 to 1,960 μg/L and a median of 49 μg/L), followed by duckweed (Lemna minor, 7-d reproduction, EC50 values ranged from 53 to 2,470 μg/L with a median of 106 μg/L) and the green alga Pseudokirchneriella subcapitata (3-d growth and reproduction, EC50 values ranged from 1,100 to 22,700 μg/L with a median 7,400 μg/L). Results from tests with the crustacean Daphnia magna (48-h survival) and fathead minnow (Pimephales promelas, 7-d early life stage survival and growth) showed limited toxicity with no-observed-effect concentrations at or near 10 mg/L. Fish dry weights obtained in the ciprofloxacin, levofloxacin, and ofloxacin treatments (10 mg/L) were significantly higher than in control fish. The hazard of adverse effects occurring to the tested organisms in the environment was quantified by using hazard quotients. An estimated environmental concentration of 1 μg/L was chosen based on measured environmental concentrations previously reported in surface water; at this level, only M. aeruginosa may be at risk in surface water. However, the selective toxicity of these compounds may have implications for aquatic community structure.
Toxicity assessment of mono-substituted benzenes and phenols using a Pseudomonas initial oxygen uptake assay
Authors: Huang Ded-Shih , Whang Thou-Jen , Cheng Fei-Chen , Wu Ya-Ping , Wang Yi-Ting , Luo Wen-I , Wang Yane-Shih
Published: January 2005

A methodology is presented for assessing the toxicity of chemical substances through their inhibitory action toward the Pseudomonas initial oxygen uptake (PIOU) rate. The current studies reveal that the PIOU assay is rapid, cost-efficient, and easy to perform. The oxygen uptake rate was found to be associated with a putative benzoate transporter and highly dependent on benzoate concentration. The putative benzoate transporter has been shown to follow Michaelis–Menten kinetics. Most phenols were found to be noncompetitive inhibitors of the benzoate transporter. The inhibition constant (Ki) of these noncompetitive inhibitors can be related to the concentration causing 50% oxygen uptake inhibition in Pseudomonas putida. Modeling these data by using the response–surface approach leads to the development of a quantitative structure–activity relationship (QSAR) for the toxicity of phenols ((1/Ki) = –0.435 (±0.038) lowest-unoccupied-molecular orbital + 0.517 (±0.027)log KOW −2.340 (±0.068), n = 49, r2 = 0.930, s = 0.107, r2adj = 0.926, F = 303.1). A comparison of QSAR models derived from the Ki data of the PIOU method and the toxicity data of 40-h Tetrahymena pyrifomis growth inhibition assay (Tetratox) indicated that there was a high correlation between the two approaches (r2 = 0.925).
Polycyclic aromatic hydrocarbon behavior in bioactive soil slurry reactors amended with a nonionic surfactant
Authors: Kim Han S. , Weber Walter J.
Published: January 2005

The effects of an ethoxylated sorbitan fatty ester nonionic surfactant (Tween 80) on the bioavailability of polycyclic aromatic hydrocarbons (PAHs) were examined by using soil-free and dense-slurry (67% solids content, by wt) systems containing a creosote-contaminated field soil. The dispersed-micelle-phase PAHs in soil-free systems were not readily bioavailable to the mixed consortium of microbes indigenous to the creosote-contaminated soil. Instead, the microbes partially and preferentially utilized readily available portions of the surfactant as carbon sources (16–18% of the initial surfactant dose). This selective microbial attack resulted in destabilization of dispersed-phase micelles and significant decreases in molar solubilization ratio and micelle-water partition coefficient values. Remarkably high dosages (>20 g/L) of Tween 80 were required to enhance mobilization of the sorbed PAHs via micelle association because of the sorption of Tween 80 to the soil employed. The PAHs released from the destabilized micelles in soil-slurry systems either associated with sorbed-phase surfactants or readsorbed to soil organic matter too rapidly to be biologically accessed, even by the acclimated PAH-degrading microbes present. The work provides important new information and practical insights to surfactant solubilization and mobilization technology applications for the bioremediation of PAH-contaminated soils and sediments.
Relationships between Cd and Zn partitioning and geochemical composition in sediments from Chinese Rivers
Authors: Peng Shu-Heng , Wang Wen-Xiong , Chen Jingsheng
Published: January 2005

Asorption isotherm experiments were conducted to determine the distribution coefficients (Kd) for Cd and Zn between water and sediments from twelve rivers in eastern China. The low metal concentration (<10−10 M) added into the sediment-water system enabled the direct measurements of linear adsorption isotherms. When other solution parameters, such as ionic strength, were controlled, sediment geochemical characteristics were the major factors affecting metal distribution. The Kd was highly dependent on the total organic carbon contents and Fe-Mn oxide at pH = 7.0, and was affected significantly by the carbonate content in the sediments due to its control of pH. The Kd of the Huanghe sediments, which had the highest carbonate concentration (13.1%), increased sharply for both Cd and Zn when the pH increased. A quantitative model using the experimentally obtained phase distribution coefficients (Kd)i was applied to study the effects of different geochemical phases in the sediment on metal distributions. The (Kd)i of carbonate was correlated significantly with the carbonate content in the sediment, whereas the (Kd)i of total organic carbon (TOC) and Fe-Mn oxide phases were highly pH dependent. Using the (Kd)i for each geochemical phase, the calculation showed that about 91% and 85% of sorbed Cd and Zn, respectively, added to the batch reactors were distributed among the three major geochemical phases: TOC, Fe-Mn oxide, and carbonate. Total organic carbon was the most important binding phase for Cd, and Fe-Mn oxide for Zn. Furthermore, adsorption experiments with simulated sediments show the importance of interactions between different geochemical phases on metal partitioning.
Turner Syndrome
Authors: Sybert Virginia P.
Published: January 2005

Turner syndrome affects 1/3000 females. The natural history of this sex chromosome aneuploidy is marked by problems in lymphatic development, skeletal development and growth, gonadal function, cardiac and renal malformations, and a number of specific cognitive findings. An increased risk for hypothyroidism, sensorineural hearing loss, hypertension, and other problems is recognized. Evaluation and management are reviewed.
Influence of processing conditions on the weld line in doubly injection‐molded glassy polycarbonate and polystyrene: Microindentation hardness study
Authors: Boyanova M. , Calleja F. J. Baltá , Fakirov S. , Kuehnert I. , Mennig G.
Published: January 2005

The microhardness (H) technique has been used to characterize the quality of the weld line in injection‐molded tensile bars from a two‐component machine in which both melt streams from the same material can be independently controlled. More specific, the influence of melt temperature and indentation location (closer or further from the sample edge parallel to the injection direction and across the weld line) has been followed on polycarbonate (PC) and polystyrene (PS) glassy samples. For both polymers at lower melt temperatures, a strong H decrease (between 15 and 50%) followed by a sharp increase in a narrow distance (around 0.10 mm), is observed. When the melt temperature increases up to 300°C (for PC) and 270°C (for PS), a much smaller H decrease is observed in the central part of the samples. However, closer to the tensile bar edges (2 mm) the weld line remains undetectable by microhardness measurements. The present results reveal that the processing temperature affects the broadening of the weld line through the conditions for effective mutual interdiffusion of chains from the two fronts coming from opposite sides. © 2005 Wiley Periodicals, Inc. Adv Polym Techn 24:14–20, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20028
Wear and thermal effects in low modulus polymer‐based composite friction materials
Authors: Haddadi E. , Abbasi F. , Shojaei A.
Published: January 2005

The wear properties of low modulus polymer‐based friction materials were studied. The wear equation W = K Pa Vb tc was used to correlate the wear of polymer‐based friction material sliding against cast iron with the wear coefficient (K), load (P), speed (V), and time (t). The parameters were determined experimentally by varying only one variable at a time and keeping the other two variables constant. The wear rate of selected polymer‐based friction material was compared with cast iron friction material. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1181–1188, 2005
Excess volume of polymer/solvent mixtures and proposed model for prediction of activity of solvents based on excess volume data
Authors: Eliassi Ali , Modarress Hamid
Published: January 2005

Density measurements were used to evaluate the excess volume of binary mixtures of poly(ethylene glycol) in water and ethanol solvents, poly(propylene glycol) in water and ethanol solvents, and poly(vinyl alcohol) in water solvent at different temperatures for various molecular weights of polymers. The excess volumes were correlated and expressed by a polynomial in terms of the weight fraction of the polymer. The activity of the solvent was expressed in terms of three parts: excess internal energy, excess entropy, and excess volume. The excess volume was derived from the expression obtained in this work, the excess entropy was derived from Flory's lattice model, and the excess internal energy was used as a weight average of the excess volume and entropy parts. The results indicated good agreement between the activity of the solvent calculated by the proposed model and the experimental data. The proposed model has the advantage that using only simple density measurements the activity values that are necessary in the calculation of thermodynamic properties can be evaluated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1219–1227, 2005
Preparation and characterization of polypropylene–montmorillonite nanocomposites generated by in situ metallocene catalyst polymerization
Authors: Hwu Jyh‐Ming , Jiang George‐J
Published: January 2005

An ion‐exchange method was applied to replace sodium cations inside the interlamellar space of montmorillonite with positively charged stearyl trimethyl ammonium chloride. The d001‐spacing of montmorillonite is larger in toluene than in other solvents. The overexchanged stearyl methyl ammonium chloride in the montmorillonite layers can be completely washed out by ethanol. Polypropylene–montmorillonite nanocomposites were prepared by using the supported rac‐Et(Ind)2ZrCl2 catalyst on the montmorillonite. The nanocomposites that were polymerized by the supported catalyst were characterized by infrared spectroscopy, nuclear magnetic resonance, X‐ray diffraction, differential scanning calorimetry, scanning electron microscopy, and transmission electron microscopy. Transmission electron microcopy shows that each silicate sheet of montmorillonite is randomly dispersed into the polypropylene matrix following polymerization by using a supported catalyst. The polypropylene nanocomposites had higher crystallinity, hardness, and thermal properties than pure polypropylene. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1228–1236, 2005
Using silica nanoparticles as curing reagents for epoxy resins to form epoxy–silica nanocomposites
Authors: Liu Ying‐Ling , Li Shu‐Hsien
Published: January 2005

Nanoscale colloidal silica showed high reactivity toward curing epoxy resins to form epoxy–silica nanocomposites under mild conditions. Adding a certain amount (5000 ppm) of magnesium chloride lowered the activation energy of the reaction from 71 to 46 kJ/mol. Less and more magnesium chloride both exhibited counter action on lowering the activation energy of the curing reaction. Tin chloride dihydrate and zinc acetylacetonate hydrate were also added into the curing compositions, however, showing no significant effect on promoting the curing reaction. Through this curing reaction, epoxy–silica nanocomposites containing high silica contents up to 70 wt % were obtained. Therefore, this reaction provided a novel and convenient route in preparation of epoxy–silica nanocomposites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1237–1245, 2005