bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Xenopus laevis as a model for investigating in vitro and in vivo endocrine disruption in amphibians
Authors: Huang Yue-wern , Matthews Jason B. , Fertuck Kirsten C. , Zacharewski Tim R. 
Published: July 2005

Abstract
The estrogenic activity of 17β-estradiol (E2), α-zearalenol (α-ZEA), genistein (GEN), and 4-t-octylphenol (4-t-OP) was investigated using Xenopus laevis-based assays. All test compounds competed with [3H]E2 for binding to a recombinant Xenopus estrogen receptor (xER) with the following relative affinities: E2 &gt; α-ZEA &gt; 4-t-OP &gt; GEN. The ability of these compounds to induce xER-mediated reporter gene expression was then assessed in MCF-7 human breast cancer cells cotransfected with a Gal4-xERdef chimeric estrogen receptor and a Gal4-regulated luciferase reporter gene. Luciferase activity was increased 30- to 50-fold by 10 nM E2 relative to that in solvent control. Maximal reporter gene activity induced by 10 nM α-ZEA was 54% of that induced by E2; however, the activity did not increase following doses of up to 10 μM. A dose of 1 μM 4-t-OP induced 23% of the maximal reporter gene activity induced by E2, whereas 10 μM GEN induced activity to the same level as E2. A dose-dependent increase in vitellogenin (VTG) mRNA expression was observed in Xenopus treated intraperitoneally with E2 at 0.05 to 5 mg/kg/d for three consecutive days, with the maximal induction observed in the group receiving 1 mg/kg/d. The α-ZEA, GEN, and 4-t-OP also significantly induced VTG mRNA expression, although at higher doses. These results demonstrate the utility of X laevis as an amphibian model to assess the estrogenic activity of endocrine disruptors.
Contaminant accumulation and biomarker responses in caged fish exposed to effluents from anthropogenic sources in the karnaphuly river, bangladesh
Authors: Al-Arabi Syed A.M. , Adolfsson-Erici Margaretha , Waagbø Rune , Ali M. S. , Goksøyr Anders 
Published: July 2005

Abstract
The possible ecotoxicological effects of a paper and pulp mill effluent were investigated by measuring selected contaminants and biomarkers in caged Nile tilapia (Oreochromis niloticus) and sharptooth catfish (Clarias gariepinus) from the Karnaphuly River, Bangladesh. Fish were caged for 28 d at two upstream reference sites (2 and 4 km) and four downstream sites (3, 5, 8, and 12 km) from the effluent outlets. Organochlorine contaminants and bile biomarkers were bioaccumulated to higher levels at downstream polluted sites than at the reference sites, including hexachlorobenzene (HCB), hexachlorocyclohexane (HCH), polychlorinated biphenyls (PCBs) in liver, and chlorophenolic compounds like 2,4-dichlorophenol and 2,4,6-trichlorophenol in bile. Levels of glucose, protein, and aspartate aminotransferase were analyzed in plasma, whereas cytochrome P4501A (CYP1A) levels were determined in S-12 supernatants of liver. The results, including CYP1A induction and bile biomarkers, clearly indicated that, in addition to the paper and pulp mill effluents, the downstream sites appear to receive other inputs of contaminants. This field assessment in a Bangladeshi river demonstrates biomarker measurements in caged fish as a promising approach for evaluating accumulation and effects of industrial effluents in fish of developing countries.
A new biodegradation prediction model specific to petroleum hydrocarbons
Authors: Howard Philip , Meylan William , Aronson Dallas , Stiteler William , Tunkel Jay , Comber Michael , Parkerton Thomas F. 
Published: July 2005

Abstract
A new predictive model for determining quantitative primary biodegradation half-lives of individual petroleum hydrocarbons has been developed. This model uses a fragment-based approach similar to that of several other biodegradation models, such as those within the Biodegradation Probability Program (BIOWIN) estimation program. In the present study, a half-life in days is estimated using multiple linear regression against counts of 31 distinct molecular fragments. The model was developed using a data set consisting of 175 compounds with environmentally relevant experimental data that was divided into training and validation sets. The original fragments from the Ministry of International Trade and Industry BIOWIN model were used initially as structural descriptors and additional fragments were then added to better describe the ring systems found in petroleum hydrocarbons and to adjust for nonlinearity within the experimental data. The training and validation sets had r2 values of 0.91 and 0.81, respectively.
Sorbate size-dependent maximum capacities for adsorption of organic compounds in the slowly and very slowly desorbing domains of a sediment
Authors: van den Heuvel Henny , van Noort Paul 
Published: July 2005

Abstract
Maximum capacities were determined for adsorption of six polycyclic aromatic hydrocarbons, seven polychlorinated biphenyls, and five chlorobenzenes in both the slowly desorbing domain and the very slowly desorbing domain of a sediment. For separate compound classes in the two desorption domains, log-transformed maximum adsorption capacities were linearly related to the relative magnitude of the shadow of the sorbate on an imaginary planar surface. For planar compounds, the ratio of maximum adsorption capacities for the slowly desorbing domain and the very slowly desorbing domain was approximately two. This ratio was eightfold higher for strongly nonplanar polychlorinated biphenyls, which suggests that adsorption depends on sorbate thickness in the very slow desorption domain but not in the slow desorption domain. The rates of decrease of the log-transformed sum of maximum capacities for adsorption in the slow desorption domain and the very slow desorption domain with increasing relative magnitude of the shadow of the sorbate on a planar surface were similar to those derived from literature data regarding maximum capacities for adsorption onto a soil and a sediment. It is proposed that the rates of decrease for both the slow desorption domain and the very slow desorption domain may have general applicability to soils and sediments.
Accumulation of hexahydro-1,3,5-trinitro-1,3,5-triazine in channel catfish (ictalurus punctatus) and aquatic oligochaetes (lumbriculus variegatus)
Authors: Belden Jason B. , Lotufo Guilherme R. , Lydy Michael J. 
Published: July 2005

Abstract
The extensively used military explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has been widely released to the environment during production, usage, and disposal operations. Toxic effects of RDX have been reported in terrestrial and aquatic receptors, but investigations regarding the bioaccumulation potential of RDX in aquatic systems are scarce. The objective of the present study was to describe the toxicokinetics of RDX during aqueous exposure for the channel catfish (Ictalurus punctatus) and aquatic oligochaetes (Lumbriculus variegatus) and to compare the amount of RDX accumulation in juvenile catfish following aqueous exposure only, dietary exposure only, and a combination of dietary and aqueous exposure. The toxicokinetics measurements included bioconcentration factors (BCFs), uptake rates, elimination rates, and biological half-lives. First-order, single-compartment models described the toxicokinetics for both species. Uptake of RDX into oligochaetes was relatively rapid (uptake clearance constant [ku] of 5.17 ml/g/h) compared to that in catfish (ku = 1.28 ml/g/h). However, elimination also was more rapid in oligochaetes, with biological half-lives of 0.28 and 1.09 h for oligochaetes and catfish, respectively. Thus, both species had very similar estimated BCFs of 2.1 ml/g for oligochaetes and 2.0 ml/g for catfish. Accumulation of RDX in fish that were fed oligochaetes exposed to an exceedingly high water concentration of RDX was minimal. The present investigation indicates that RDX uptake via the aqueous route is the expected dominant uptake pathway, with dietary uptake contributing minimally to the overall body burden in fish inhabiting RDX-contaminated sites. Because of the exceedingly low bioaccumulative potential and low reported toxicity of RDX, the presence of this explosive in aquatic systems is unlikely to pose unacceptable risks to invertebrates and fish.
Effect of soil properties and aging on the toxicity of copper for enchytraeus albidus, enchytraeus luxuriosus, and folsomia candida
Authors: de Barros Amorim Mónica João , Römbke Jorg , Schallnaß Hans-Joachim , Soares Amadeu Mortágua Velho Maia 
Published: July 2005

Abstract
In the present study, the effect of the heavy-metal salt copper chloride (CuCl2-2H2O) in soils freshly spiked (3 d) and aged (70 ± 10 d; mean ± SD) was studied in the test species Enchytraeus albidus, E. luxuriosus, and Folsomia Candida. Up to nine soils were used: Besides the Organisation for Economic Co-operation and Development (OECD) artificial soil and the Agricultural Testing and Research Agency (Landwirtschaftliche Untersuchungs- und Forschungsanstalt, Speyer, Germany) 2.2 natural standard soils, the others were selected based on the EURO Soil approach, taking into account the effect of different soil parameters (pH, organic matter, grain size distribution, and carbon to nitrogen ratio). Additionally, the effect of the chloride ions was studied separately. The results revealed the following: First, a soil effect was observed; for example, in F. Candida, median effective concentrations (EC50s) varied between 262 mg/kg in a sample from the same site as the original EURO Soil 5 soil and greater than 1,000 mg/kg in OECD soil. Second, an aging effect was observed, mainly in F. Candida. For example, toxicity of offspring survival was increased twofold in the OECD soil and approximately eightfold with aging in the EURO Soil 7 soil, whereas the enchytraeid species did not react differently after aging. Third, an effect of chloride ions on reproduction of the animals was found; however, this effect was independent of the aging period. Fourth, species variation was seen in terms of sensitivity (EC50), decreasing in the following order: E. luxuriosus &gt; E. albidus » F. Candida. Differences in toxicity of offspring survival between enchytraeids and F. Candida might be explained by the different routes of uptake.
Metamorphosis of two amphibian species after chronic cadmium exposure in outdoor aquatic mesocosms
Authors: James Stacy M. , Little Edward E. , Semlitsch Raymond D. 
Published: July 2005

Abstract
Amphibian larvae at contaminated sites may experience an alteration of metamorphic traits and survival compared to amphibians in uncontaminated conditions. Effects of chronic cadmium (Cd) exposure on the metamorphosis of American toads (Bufo americanus) and southern leopard frogs (Rana sphenocephala) were determined. The two species were reared separately from shortly after hatching through metamorphosis in outdoor mesocosms (1,325-L polyethylene cattle tanks) that simulated natural ponds and enhanced environmental realism relative to the laboratory. Both species exhibited a decrease in survival with increasing initial nominal aqueous Cd concentration. Cadmium treatment did not influence mass at metamorphosis for either species when survival was included as a covariate, but increased the age at metamorphosis for the American toads. The whole body Cd content of metamorphs increased with aqueous Cd treatment level for both species, and the American toads tended to possess more elevated residues. Cadmium quickly partitioned out of the water column and accumulated in and altered the abundance of the tadpoles' diet. Cadmium-contaminated sites may produce fewer metamorphs, and those that survive will metamorphose later and contain Cd. Interspecific differences in the response variables illustrate the importance of testing multiple species when assessing risk.
On constructing completions
Authors: Crosilla Laura , Ishihara Hajime , Schuster Peter 
Published: July 2005

AbstractThe Dedekind cuts in an ordered set form a set in the sense of constructive Zermelo–Fraenkel set theory. We deduce this statement from the principle of refinement, which we distill before from the axiom of fullness. Together with exponentiation, refinement is equivalent to fullness. None of the defining properties of an ordering is needed, and only refinement for two–element coverings is used.In particular, the Dedekind reals form a set: whence we have also refined an earlier result by Aczel and Rathjen, who invoked the full form of fullness. To further generalise this, we look at Richman's method to complete an arbitrary metric space without sequences, which he designed to avoid countable choice. The completion of a separable metric space turns out to be a set even if the original space is a proper class: in particular, every complete separable metric space automatically is a set.
Numerical study on the underground coal gasification for inclined seams
Authors: Yang Lanhe 
Published: July 2005

AbstractAccording to the characteristics for combustion and gasification reactions occurring in the gasification gallery, the mathematical functional relationship between the chemical reaction rate and every influencing factor is studied. The dynamic nonlinear coupling mathematical models on underground coal gasification of inclined seams are established. The determination methods of major model parameters are introduced. Additionally, the control volume method is adopted to find the numerical solution to the mathematical models. The patterns of development and variation for temperature field, concentration field and pressure field in gasification panel are studied. On the basis of the model test, calculation results are analyzed. From the distribution of temperature field, its calculation value is a little higher than the experimental one, with the relative error of every measuring point virtually within 17%. Research shows that, the experiment value of gas heat value and calculated value take on a good conformity; due to the influence of temperature, in the high temperature zone, the change gradient of the experiment value for concentration field of gas compositions is greater than that of the calculation value. The simulated results indicate that the relative error of the pressure field calculation is 4.13%–12.69% and 8.25%–17.47%, respectively, 7 h and 45 h after the ignition. The drop rate for the fluid pressure is 6.01% and 10.91%, respectively. Research shows that the simulated values conform with experimental values comparatively well, which demonstrates that the numerical simulation on the “three fields” in underground coal gasification is correct. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Enrichment using antibody‐coated microfluidic chambers in shear flow: Model mixtures of human lymphocytes
Authors: Sin Aaron , Murthy Shashi K. , Revzin Alexander , Tompkins Ronald G. , Toner Mehmet 
Published: July 2005

AbstractIsolation of phenotypically‐pure cell subpopulations from heterogeneous cell mixtures such as blood is a difficult yet fundamentally important task. Current techniques such as fluorescent activated cell sorting (FACS) and magnetic‐activated cell sorting (MACS) require pre‐incubation with antibodies which lead to processing times of at least 15–60 min. In this study, we explored the use of antibody‐coated microfluidic chambers to negative deplete undesired cell types, thus obtaining an enriched cell subpopulation at the outlet. We used human lymphocyte cell lines, MOLT‐3 and Raji, as a model system to examine the dynamic cell binding behavior on antibody coated surfaces under shear flow. Shear stress ranging between 0.75 and 1.0 dyn/cm2 was found to provide most efficient separation. Cell adhesion was shown to follow pseudo‐first order kinetics, and an anti‐CD19 coated (Raji‐depletion) device with ∼2.6 min residence time was demonstrated to produce 100% pure MOLT‐3 cells from 50‐50 MOLT‐3/Raji mixture. We have developed a mathematical model of the separation device based on the experimentally determined kinetic parameters that can be extended to design future separation modules for other cell mixtures. We conclude that we can design microfluidic devices that exploits the kinetics of dynamic cell adhesion to antibody coated surfaces to provide enriched cell subpopulations within minutes of total processing time. © 2005 Wiley Periodicals, Inc.
Continuous operation of foamed emulsion bioreactors treating toluene vapors
Authors: Kan Eunsung , Deshusses Marc A. 
Published: July 2005

AbstractContinuous operation of a new bioreactor for air pollution control called the foamed emulsion bioreactor (FEBR) has been investigated. The effect of several liquid feeding strategies was explored. The FEBR exhibited high and steady toluene removal performance (removal efficiency of 89%–94%, elimination capacity of 214–226 g/m3h at toluene inlet concentration of 1 g/m3) for up to 360 h, when 20% of the culture was replaced every 24 h by a nutrient solution containing 4 g/L of potassium nitrate as a nitrogen source. This feeding mode supported a high cell activity measured as INT reduction potential and active cell growth without being subject to nitrogen limitation. In comparison, operating the FEBR with the liquid in a closed loop (i.e., batch) resulted in a significant decrease of both the removal efficiency of toluene and INT reduction activity. Operation with feeding active cells resulted in stable and effective treatment, but would require a significant effort for mass culture preparation. Therefore, the continuous process with periodically feeding nutrients was found to be the most practical and effective operating mode. It also allows for stable operation, as was shown during removal of low concentration of toluene or after pollutant starvation. Throughout the study, INT reduction measurements provided insight into the process. INT reduction activity data proved that under normal operating conditions, the FEBR performance was limited by both the kinetics and by mass transfer. Overall, the results illustrate that engineered gas‐phase bioreactors can potentially be more effective than conventional biofilters and biotrickling filters for the treatment of air pollutants such as toluene. © 2005 Wiley Periodicals, Inc.
Are Hormones from the Neuropeptide Y Family Recognized by Their Receptors from the Membrane‐Bound State?
Authors: Bader Reto , Zerbe Oliver 
Published: July 2005

AbstractHormones and many other neurotransmitters, growth factors, odorant molecules, and light all present stimuli for a class of membrane‐anchored receptors called G protein‐coupled receptors (GPCRs). The GPCRs are the largest family of cell‐surface receptors involved in signal transduction. About 1 % of all known genes of Drosophila and more than 5 % of the genes of Caenorhabditis elegans encode GPCRs. In addition, more than 50 % of current therapeutic agents on the market target these receptors. When the enormous biological and pharmaceutical importance of these receptors is considered, it is surprising how little is known about the mechanism with which these receptors recognize their natural ligands. In this review we present a structural approach, utilizing techniques of high‐resolution NMR spectroscopy, to address the question of whether peptides from the neuropeptide Y family of neurohormones are recognized directly from solution or from the membrane‐bound state. In our studies we discovered that the structures of the membrane‐bound species are better correlated to the pharmacological properties of these peptides than the solution structures are. These findings are supported by the observation that many biophysical properties of these peptides seem to be optimized for membrane binding. We finally present a scenario of possible events during receptor recognition.
Functional expression of the peptide transporter PEPT2 in the mammalian enteric nervous system
Authors: Rühl Anne , Hoppe Susanne , Frey Isabelle , Daniel Hannelore , Schemann Michael 
Published: July 2005

AbstractThe peptide transporter PEPT2 mediates transmembrane uptake of small peptides. So far, its expression has not been evidenced in the gastrointestinal tract. We have investigated peptide transport activity in the neuromuscular layers of the gastrointestinal tract by using the fluorescent tracer‐dipeptide β‐Ala‐Lys‐Nϵ‐7‐amino‐4‐methyl‐coumarin‐3‐acetic acid (Ala‐Lys‐AMCA). Whole‐mount preparations from mouse, rat, and guinea pig stomach and small and large intestine were incubated with Ala‐Lys‐AMCA in the presence or absence of the uptake‐inhibitors L‐histidine, D‐phenylalanyl‐L‐alanine (D‐Phe‐Ala), glycyl‐L‐sarcosine (Gly‐Sar), glycyl‐L‐glutamine (Gly‐Gln), benzylpenicillin, and cefadroxil. Fluorescence microscopy revealed that Ala‐Lys‐AMCA specifically accumulated in both ganglionic layers of the enteric nervous system (ENS) in all regions and species studied. This could be inhibited by Gly‐Sar, D‐Phe‐Ala, Gly‐Gln, and cefadroxil, but not by free histidine and benzylpenicillin, indicating uptake via PEPT2. Accordingly, dipeptide uptake was completely abolished in PEPT2‐deficient mice. Reverse transcriptase‐polymerase chain reaction analysis detected a PEPT2‐specific transcript in extracts from the ganglionic ENS layers of mouse small and large intestine, further proving that enteric dipeptide transport activity is specifically mediated via PEPT2. The cellular site of dipeptide uptake was immunohistochemically localized to enteric glial cells and tissue‐resident macrophages. In addition, dipeptide uptake occurred in a neurochemically defined subset of neurons in the guinea pig ENS. Our results constitute the first functional evidence for dipeptide transport activity in the ENS. PEPT2‐mediated dipeptide transport in enteric glia could contribute to the clearance of neuropeptides in the ENS. In addition, the fluorophore‐coupled dipeptide uptake via PEPT2 is a novel vital marker for glial cells in the ENS. J. Comp. Neurol. 490:1–11, 2005. © 2005 Wiley‐Liss, Inc.
Definition and novel connections of the entopallium in the pigeon (Columba livia)
Authors: Krützfeldt Nils O.E. , Wild J. Martin 
Published: July 2005

AbstractThe avian entopallium (E) is the major thalamorecipient zone, within the telencephalon, of the tectofugal visual system. Because of discrepancies concerning the structure of this nuclear mass in pigeons, and in light of recent evidence concerning entopallial projections in other avian species, we here redefine and chart some novel entopallial projections in the pigeon by using a combination of cytochrome oxidase (CO) activity, calcium binding protein immunohistochemistry (CBPi), normal histology, and tract tracing. We show that 1) E is defined by the accurate overlap of CO activity and the dense terminations of thalamic (rotundal) efferents; 2) the perientopallium (Ep), E's overlying belt region, receives a relatively sparse rotundal input and is a major source of projections to wider regions of the hemisphere; and 3) E can be subdivided into internal (Ei) and external (Ex) portions on the basis of normal histology, CBPi, and differential projections. Thus, Ei, but not Ex, makes a reciprocal connection with a distinct nucleus in the ventrolateral mesopallium and is a major source of projections to the lateral striatum. These findings suggest the necessity for a revision of the original proposal of a strictly serial flow of visual information through the entopallial complex and further regions of the hemisphere and also require a modification of the long‐standing view that E is comparable to only one specific lamina (IV) of extrastriate visual cortex of mammals (Karten and Hodos [1970] J. Comp. Neurol. 140:35–51; Shimizu and Karten [1990] In: Finlay BL, et al., editors. The neocortex. New York: Plenum Press. p 75–86). Rather, E appears to be composed of a variety of neuronal types possibly equivalent to those in several neocortical laminae. J. Comp. Neurol. 490:40–56, 2005. © 2005 Wiley‐Liss, Inc.