bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicity of a cadmium-contaminated diet to Hyalella azteca
Authors: Ball Angela L. , Borgmann Uwe , Dixon D. George 
Published: August 2006

Abstract
Four- and 10-week chronic toxicity tests were conducted using the freshwater amphipod Hyalella azteca and Cd-contaminated Chlorella sp. as a food source. Chlorella sp. was cultured in various Cd concentrations, filtered from solution, rinsed, dried, and ground into food flakes the for H. azteca. Unlike Cd toxicity from water sources, growth was found to be a more sensitive toxicological endpoint than survival, with calculated 50 and 25% effect concentrations (EC50s and EC25s, respectively) of 5.43 and 2.82 nmol/g, respectively, for Cd measured in food. Based on the regression of Cd in Chlorella sp. against Cd in filtered culture medium, the EC50 and EC25 corresponded to dissolved Cd concentrations of 11.30 and 5.09 nmol/L, respectively. Little or no bioaccumulation of Cd was found in the tissues of H. azteca that were fed contaminated food. These results demonstrate an apparent toxicological effect (either direct or indirect) of Cd-contaminated Chlorella sp. to H. azteca that is not associated with Cd accumulation. Toxicity of Cd-contaminated Chlorella sp. differs from waterborne Cd toxicity both in terms of the most sensitive endpoint (growth vs survival) and the relationship between toxicity and bioaccumulation. Unlike Cd toxicity through water exposure, Cd bioaccumulation by H. azteca cannot, therefore, be used to infer toxicity of Cd in a diet of Chlorella sp. Although the concentration of Cd in the algal culture medium that ultimately reduced growth of H. azteca in the present study was higher than Cd in water, which caused mortality to H. azteca in water-only tests during previous studies, further research regarding the contribution of dietary Cd to overall Cd toxicity is needed to verify that water-quality guidelines and risk assessments based on water-only exposures are fully protective.
Ecological consequences of copper contamination in macroalgae: Effects on epifauna and associated herbivores
Authors: Roberts David A. , Poore Alistair G.B. , Johnston Emma L. 
Published: August 2006

AbstractMany contaminants of the marine environment are able to chelate to sediments, bind within organic matrices, or be accumulated by organisms such as invertebrates and macroalgae. Marine macroalgae are recognized as effective and efficient bioaccumulators of heavy metals and are sometimes used as bioindicators. Macroalgae support abundant and diverse communities of mobile invertebrates that play key roles in temperate marine environments. However, the potential ecological consequences of the contamination of algae on associated epifauna are yet to be considered. In this study, the brown alga Sargassum linearifolium was experimentally spiked with copper to assess the effects of contamination on epifaunal invertebrates in both field and laboratory assays. Copper contamination greatly reduced the colonization of a variety of epifaunal taxa in the field. Laboratory assays further examined the effects of contaminated macroalgae on habitat preferences, feeding rates, survivorship, and growth in the herbivorous amphipod Peramphithoe parmerong. Adult P. parmerong were less likely to select spiked macroalgae in short-term habitat preference assays and consumed spiked algae at lower rates in feeding assays. In a longer-term (30-d) experiment, survivorship of juvenile amphipods was reduced by up to 75% by contaminated macroalgae, but no effects on the growth of survivors was observed. Heavy metal contamination of macroalgae is a widespread phenomenon that has the potential for substantial negative consequences for associated invertebrate fauna. This issue warrants further investigation by marine ecotoxicologists.
Bioaccumulation of native polycyclic aromatic hydrocarbons from sediment by a polychaete and a gastropod: Freely dissolved concentrations and activated carbon amendment
Authors: Cornelissen Gerard , Breedveld Gijs D. , Næs Kristoffer , Oen Amy M.P. , Ruus Anders 
Published: August 2006

Abstract
The present paper describes a study on the bioaccumulation of native polycyclic aromatic hydrocarbons (PAHs) from three harbors in Norway using the polychaete Nereis diversicolor and the gastropod Hinia reticulata. First, biota–sediment accumulation factors (BSAFs) were measured in laboratory bioassays using the original sediments. Median BSAFs were 0.004 to 0.01 kg organic carbon/kg lipid (10 PAHs and 6 organism–sediment combinations), which was a factor of 89 to 240 below the theoretical BSAF based on total sediment contents (which is approximately one). However, if BSAFs were calculated on the basis of measured freely dissolved PAH concentrations in the pore water (measured with polyoxymethylene passive samplers), it appeared that these BSAFfree values agreed well with the measured BSAFs, within a factor of 1.7 to 4.3 (median values for 10 PAHs and six organism–sediment combinations). This means that for bioaccumulation, freely dissolved pore-water concentrations appear to be a much better measure than total sediment contents. Second, we tested the effect of 2% (of sediment dry wt) activated carbon (AC) amendments on BSAF. The BSAFs were significantly reduced by a factor of six to seven for N. diversicolor in two sediments (i.e., two of six organism–sediment combinations), whereas no significant reduction was observed for H. reticulata. This implies that either site-specific evaluations of AC amendment are necessary, using several site-relevant benthic organisms, or that the physiology of H. reticulata caused artifactually high BSAF values in the presence of AC.
Effect of dynamic vulcanization on co‐continuous morphology
Authors: Bhadane Prashant A. , Virgilio Nick , Favis Basil D. , Champagne Michel F. , Huneault Michel A. , Tofan Florin 
Published: August 2006

AbstractThis study examines the effect of dynamic vulcanization on the co‐continuous morphology in ethylene‐propylene‐diene terpolymer (EPDM)/polypropylene (PP) blends using a technique of morphology investigation involving focused ion beam (FIB) etching of the sample surface, followed by topological investigation of the sample surface using tapping mode atomic force microscopy (TMAFM). The FIB ion etching rates of EPDM and PP are distinctly different, and these differences create a significant topological contrast between the phases when subsequently analyzed by atomic force microscopy. This approach allows for the high‐resolution observation of dispersed EPDM, and phases as small as 100 nm, are clearly identified. Since it is shown that the etching rates of noncrosslinked and crosslinked EPDM are similar, it was necessary to selectively remove the noncrosslinked EPDM phase by solvent dissolution. This combination of techniques then allows for the clear distinction of polypropylene, as well as noncrosslinked and crosslinked EPDM phases in the blend. The high‐resolution micrographs together with the continuity data, surprisingly, indicate that a noncrosslinked co‐continuous EPDM phase (α‐network) transits to a finer network of crosslinked EPDM (β‐network) after dynamic crosslinking. It is suggested that this β‐network is produced as a result of the viscosity mismatch between the noncrosslinked and crosslinked EPDM melt occurring at the outer envelope of the α‐network during dynamic crosslinking. As the crosslinked material pulls away from the noncrosslinked material under dynamic melt mixing conditions, it creates a smearing effect. It is shown that the initial α‐network maintains its continuity and demonstrates a diminished pore diameter as crosslinking proceeds. Furthermore, when the noncrosslinked material is extracted almost no crosslinked phase (<1%) is found to be present in the extract. These results strongly indicate that the crosslinking proceeds initially at the outer envelope of the EPDM phase, and works its way toward the center. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Dehydration of glycerol to acetol via catalytic reactive distillation
Authors: Chiu Chuang‐Wei , Dasari Mohanprasad A. , Suppes Galen J. , Sutterlin Willam R. 
Published: August 2006

AbstractDehydration of glycerol was performed in the presence of various metallic catalysts including alumina, magnesium, ruthenium, nickel, platinum, palladium, copper, raney nickel, and copper‐chromite catalysts to obtain acetol in a single‐stage reactive distillation unit under mild conditions. The effects of operation mode, catalyst selection, glycerol‐feed flow rate, catalyst loading, and initial water content were studied to arrive at optimum conditions. High‐acetol selectivity levels (> 90%) were achieved using copper‐chromite catalyst, and operating in semi‐batch reactive distillation mode. A small amount of water content in glycerol feedstock was found to reduce the tendency for residue to form, therein extending catalyst life. The acetol from this reaction readily hydrogenates to form propylene glycol, providing an alternative route for converting glycerol to propylene glycol. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Segregation and dispersion of a binary system of particles in a fluidized bed
Authors: Galvin K. P. , Swann R. , Ramirez W. F. 
Published: August 2006

AbstractThe steady‐state segregation and dispersion of a binary system of particles in a liquid‐fluidized bed was investigated. One of the species had a density of 1,600 kg/m3 and the other 1,900 kg/m3, and both exhibited a narrow size range of 1.00 to 1.18 mm. A generalized model for describing the dispersion coefficient, D, was proposed. That is, D = αdUf/ϕ, where d is the particle diameter, Uf the local interstitial fluid velocity, and ϕ the local volume fraction of solids. The model had one adjustable parameter α, which was fixed at 0.7 for both particle species and for the six different superficial fluidization velocities used. The particle segregation was described with reference to the monocomponent fluidization parameters of the two species, based on the Richardson and Zaki equation. Good descriptions of the concentration profiles of the two species were produced for all superficial velocities examined. Additional experiments involving other binary systems were also conducted in order to test the generality of the model. These systems involved particles of closer settling velocities, and, hence, displayed more mixing. Very small adjustments in the terminal velocities of the species, typically 2%, were needed to achieve satisfactory agreement between the theoretical and experimental concentration profiles, with the model parameter, α, equal to 0.7. This adjustment was justified because of apparent changes in the average particle sizes of the two species due to particle‐size segregation. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Teratogen update: Pseudoephedrine
Authors: Werler Martha M. 
Published: August 2006

AbstractPseudoephedrine is contained in decongestants such as the Sudafed line of products. It is an alpha‐adrenergic receptor agonist, which causes blood vessel constriction, including the therapeutic effect of reducing airflow resistance in the nasal cavity. Pseudoephedrine is one of the most commonly used medications in pregnancy, with an estimated 25% of women exposed. It has been demonstrated that alpha‐adrenergic receptor agonists slow uterine blood flow, but their effects have not been studied in relation to most reproductive outcomes in animals or humans. Two analyses of health maintenance organization pharmacy data identified 9 malformed infants among 902 first‐trimester pseudoephedrine exposures, suggesting no association with birth defects overall; however, studies of such data sets often lack sufficient power to identify risks for specific birth defects. The related compounds, epinephrine, ephedrine, and phenylephrine, have been associated with hemorrhages and cardiovascular and limb malformations in animal models. Risk of ventricular septal defects was associated with decongestant use in pregnant women in 1 recent study. The vasoconstrictive effects of these drugs raise the hypothesis that their use in early pregnancy might increase the risk of vascular disruption defects. Case‐control studies, which often do have power to identify risks related to specific birth defects, have explored this hypothesis. Decongestant use in the first trimester has been associated with small increases in risks of 3 defects thought to arise, at least in some instances, from vascular disruption–gastroschisis, small intestinal atresia, and hemifacial microsomia. These findings are somewhat consistent in terms of magnitude of effect and suggest that risks are even greater among women also exposed to the vasoconstrictive effects of cigarette smoking. There are, however, limitations to these studies, including the possibilities of inaccurate recall of exposures and confounding by indication. In addition, the majority of decongestant use is in oral form and the question of whether intranasal formulations carry risk has not been adequately addressed. Birth Defects Research (Part A) 76:445–452, 2006. © 2006 Wiley‐Liss, Inc.
Asymmetry of skeletal effects of Dominant hemimelia
Authors: Owen Mary H. , Coull Brent A. , Holmes Lewis B. 
Published: August 2006

AbstractBACKGROUND: Dominant hemimelia (Dh) is a dominant mutation that arose spontaneously in mice; Dh animals exhibit reduced numbers of lumbar vertebrae and preaxial hindlimb defects. Absence of spleen occurs in both Dh/+ and Dh/Dh animals. This study was undertaken to characterize asymmetry of skeletal defects in the Dh mouse, specifically hindlimb asymmetries in association with axial defects. METHODS: A total of 29 Dh/+ and 100 +/+ fetuses (gestational day [GD] 18) were identified by phenotype and linked DNA and their skeletons were analyzed. RESULTS: The results revealed an asymmetry of hindlimb skeletal defects in Dh/+ animals. In +/+ fetuses, the left and right tibia were symmetrical with 99.0% of the animals possessing 6 lumbar vertebrae. However, Dh/+ fetuses showed asymmetry in length of left and right tibia and a reduction to 5 lumbar vertebrae in 86.2% of animals. There was a range from mild to severe asymmetry as evidenced by direct comparison of the length of the left to the right tibia of each animal. Tibial shortening was greater on the left than the right in 65.5% of Dh/+ fetuses; only 20.7% had symmetrical tibia. Oligodactyly, defined as absence of the first or second toe, was similarly more frequent on the left. CONCLUSIONS: Asymmetry is characteristic of many human limb malformations, although analysis of the molecular basis is difficult. Therefore, Dh/+ mice, which exhibit reduced numbers of lumbar vertebrae, asymmetric hindlimb defects, and complete absence of spleen, provide an important model for studying the relationship between axial patterning and asymmetric skeletal defects. Birth Defects Research (Part A) 76:474–482, 2006. © 2006 Wiley‐Liss, Inc.
Maternal birthplace and major congenital malformations among New York Hispanics
Authors: Zhu Motao , Druschel Charlotte , Lin Shao 
Published: August 2006

AbstractBACKGROUND: Little is known about the association between maternal nativity and congenital malformations among Hispanics living in the United States. METHODS: We conducted a cross‐sectional study to investigate the association between maternal nativity and various congenital malformations among singleton live‐births born to Hispanic women in New York from 1993 to 2001. Birth certificates, used to identify maternal birthplace, were linked with congenital malformation registry files to obtain birth defects outcome. We examined how the risk of birth defects varied by maternal birthplace by estimating the adjusted odds ratios (aORs) using logistic regression. RESULTS: A foreign maternal birth showed statistically negative associations with overall congenital malformations (aOR, 0.70; 95% CI, 0.68–0.73), cardiovascular defects (aOR, 0.85; 95% CI, 0.77–0.93), central nervous system defects (aOR, 0.76; 95% CI, 0.63–0.91), and multiple defects (aOR, 0.80; 95% CI, 0.74–0.86). Specifically, foreign‐born Hispanic women were statistically at reduced risk to deliver live babies with cleft palate (aOR, 0.56; 95% CI, 0.40–0.80), atresia and stenosis of rectum or anus (aOR, 0.58; 95% CI, 0.35–0.97), and craniosynostosis (aOR, 0.71; 95% CI, 0.51–0.99). Hispanic mothers born in Puerto Rico had a similar risk of delivering children with birth defects compared to U.S.‐born Hispanic mothers. In contrast, Hispanic mothers born in Mexico, or Cuba and Central and South America were at reduced risk of delivering infants with overall congenital malformations (aOR, 0.64; 95% CI, 0.60–0.67) and (aOR, 0.65; 95% CI, 0.63–0.68), respectively. CONCLUSIONS: Foreign‐born Hispanic mothers had a slightly lower risk to deliver live‐born singleton infants with major congenital malformations than did U.S. born Hispanic mothers. Birth Defects Research (Part A) 76:467–473, 2006. © 2006 Wiley‐Liss, Inc.
High‐density single nucleotide polymorphism screen in a large multiplex neural tube defect family refines linkage to loci at 7p21.1–pter and 2q33.1–q35
Authors: Stamm Demetra S. , Rampersaud Evadnie , Slifer Susan H. , Mehltretter Lorraine , Siegel Deborah G. , Xie Jianzhen , Hu‐Lince Diane , Craig David W. , Stephan Dietrich A. , George Timothy M. , Gilbert John R. , Speer Marcy C. ,   the NTD Collaborative Group
Published: August 2006

AbstractBACKGROUND: Neural tube defects (NTDs) are considered complex, with both genetic and environmental factors implicated. To date, no major causative genes have been identified in humans despite several investigations. The first genomewide screen in NTDs demonstrated evidence of linkage to chromosomes 7 and 10. This screen included 44 multiplex families and consisted of 402 microsatellite markers spaced ∼10 cM apart. Further investigation of the genomic screen data identified a single large multiplex family, pedigree 8776, as primarily driving the linkage results on chromosome 7. METHODS: To investigate this family more thoroughly, a high‐density single nucleotide polymorphism (SNP) screen was performed. Two‐point and multipoint linkage analyses were performed using both parametric and nonparametric methods. RESULTS: For both the microsatellite and SNP markers, linkage analysis suggested the involvement of a locus or loci proximal to the telomeric regions of chromosomes 2q and 7p, with both regions generating a LOD* score of ˜3.0 using a nonparametric identity by descent relative sharing method. CONCLUSIONS: The regions with the strongest evidence for linkage map proximal to the telomeres on these two chromosomes. In addition to mutations and/or variants in a major gene, these loci may harbor a microdeletion and/or translocation; potentially, polygenic factors may also be involved. This single family may be promising for narrowing the search for NTD susceptibility genes. Birth Defects Research (Part A) 76:499–505, 2006. © 2006 Wiley‐Liss, Inc.
Differential teratogenic response of TNFα+/+and TNFα−/−mice to cyclophosphamide: The possible role of NF‐κB
Authors: Torchinsky Arkady , Gongadze Maka , Savion Shoshana , Fein Amos , Toder Vladimir 
Published: August 2006

AbstractBACKGROUND:We observed previously that tumor necrosis factor α (TNFα)–knockout embryos are more sensitive to a cyclophosphamide (CP)–induced teratogenic insult than their TNFα‐positive counterparts, implicating molecules acting in TNFα‐activated antiapoptotic pathways in the mechanisms underlying this phenomenon. The main goal of this study was to assess whether the transcription factor nuclear factor κB (NF‐κB) may be 1 of those molecules. Such a choice is based by evidence demonstrating TNFα as a powerful activator of NF‐κB and a key role of the transcription factor in the most effective TNFα‐activated antiapoptotic cascade. Also, the expression pattern of active caspases 3, 8, and 9 was researched to assess the sensitivity of TNFα+/+and TNFα−/−embryos to CP‐induced apoptotic stimuli.METHODS:TNFα‐knockout mice were exposed to CP on day 12 of pregnancy, with or without an NF‐κB inhibitor, pyrrolidine dithiocarbamate (PDTC) and sacrificed on day 18 of pregnancy to evaluate the CP‐induced teratogenic effect. Embryos harvested 24 or 48 hr after the CP treatment were used to evaluate NF‐κB DNA‐binding and activity of caspases 3, 8, and 9.RESULTS:PDTC potentiated the CP‐induced teratogenic effect and augmented the CP‐induced suppression of NF‐κB DNA‐binding. These effects were more prominent in TNFα−/−than TNFα+/+embryos. CP‐induced caspase activation was found to be similar in TNFα−/−and TNFα+/+embryos at 24 hr after treatment. At 48 hr, TNFα−/−embryos exhibited higher levels of active caspases 8 and 9 than their TNFα‐positive counterparts.CONCLUSIONS:The results of our study allow us to hypothesize that NF‐κB may be a component of mechanisms underlying differential sensitivity of TNFα−/−and TNFα+/+mice to CP‐induced teratogenic insult. Birth Defects Research (Part A) 76:437–444, 2006. © 2006 Wiley‐Liss, Inc.
Evidence for a functional genetic polymorphism of the human retinoic acid–metabolizing enzyme CYP26A1, an enzyme that may be involved in spina bifida
Authors: Rat Emmanuel , Billaut‐Laden Ingrid , Allorge Delphine , Lo‐Guidice Jean‐Marc , Tellier Marie , Cauffiez Christelle , Jonckheere Nicolas , van Seuningen Isabelle , Lhermitte Michel , Romano Antonio , Guéant Jean‐Louis , Broly Franck 
Published: August 2006

AbstractBACKGROUND: CYP26A1, together with CYP26B1 and CYP26C1, are key enzymes of all‐trans retinoic acid (RA) inactivation and their specific and restricted expression in developing embryos participate in the fine tuning RA levels. As RA is a critical regulator of gene expression during embryonic development, the imbalance between the synthesis and degradation of RA during embryogenesis could contribute to malformations and developmental defects. METHODS: A PCR–single strand conformation polymorphism (PCR‐SSCP) strategy was developed to screen for CYP26A1 sequence variations that could affect the enzyme expression and/or activity and applied to DNA samples from 80 unrelated Caucasians, comprising 40 French healthy volunteers and 40 Italian patients with spina bifida. The consequence of the 1‐bp deletion identified in the coding sequence was investigated by an in vitro functional assay using COS‐7 cells. RESULTS: A total of 7 polymorphisms were identified, comprising 1 nucleotide deletion in the coding sequence (g.3116delT) that results in a frameshift and consequently in the creation of a premature stop codon. The g.3116delT mutation is of particular interest because it was identified in a patient with spina bifida and likely encodes a truncated protein with no enzymatic activity, as demonstrated by our preliminary in vitro data. CONCLUSIONS: Despite the fact that our findings could not show any evidence that the CYP26A1 genetic polymorphism has implications in the pathogenesis of spina bifida, this work represents the first description of a functional genetic polymorphism affecting the coding sequence of the human CYP26A1 gene. Birth Defects Research (Part A) 76:491–498, 2006. © 2006 Wiley‐Liss, Inc.