bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculation Procedures for Molecular Lipophilicity: a Comparative Study
Authors: Mannhold Raimund , Dross Karl 
Published: October 2006

AbstractThe predictive power of 14 calculation procedures for molecular lipophilicity is checked by comparing with reliable experimental log P values from the literature. The database of 138 test compounds comprises 90 simple organic structures and 48 chemically heterogeneous drug molecules (β‐blockers, class I antiarrhythmics and neuroleptics).The present investigations lead us to conclude that the predictive power of the calculation procedures is significantly better for simple organic molecules than for chemically heterogeneous drug structures. The calculation procedures should be arranged in three groups with significantly differing predictive power: fragmental > atom‐based > conformation‐dependent approaches.
Bringing science to life: A synthesis of the research evidence on the effects of context‐based and STS approaches to science teaching
Authors: Bennett Judith , Lubben Fred , Hogarth Sylvia 
Published: October 2006

AbstractContext‐based and science–technology–society (STS) approaches to teaching science in high school have become widely used over the past two decades. They aspire to foster more positive attitudes to science while, at the same time, provide a sound basis of scientific understanding for further study. This paper reviews the detailed research evidence from 17 experimental studies undertaken in eight different countries on the effects of context‐based and STS approaches, drawing on the findings of two systematic reviews of the research literature. The review findings indicate that context‐based/STS approaches result in improvement in attitudes to science and that the understanding of scientific ideas developed is comparable to that of conventional approaches. The approaches also result in more positive attitudes to science in both girls and boys and reduce the gender differences in attitudes. The paper also considers issues emerging from work in the area in relation to study design and the constraints which may militate against the use of experimental research designs when gathering evidence of impact of interventions. A fundamental constraint is the extent to which it is possible to make comparisons between existing methods and interventions when the aims are overlapping but also differ in significant ways. © 2006 Wiley Periodicals, Inc. Sci Ed 91:347–370, 2007
Techniques to improve exploration efficiency of parallel self‐adaptive genetic algorithms by dispensing with iteration and synchronization
Authors: Takashima Eiichi , Murata Yoshihiro , Shibata Naoki , Ito Minoru 
Published: October 2006

AbstractThe exploration efficiency of GAs depends on parameter values such as the mutation rate and crossover rate. To save the labor of manually adjusting these values, GAs which automatically adjust parameters (adaptive GAs) have been proposed. However, most of the existing adaptive GAs can adjust only a few parameters simultaneously. Although several adaptive GAs can adjust many parameters simultaneously, these algorithms have a large computational cost.In this paper, we propose the Self‐Adaptive Island GA (SAIGA) and its asynchronous implementation Asynchronous SAIGA (A‐SAIGA). These two GAs are combinations of Meta GA and Island GA, and can adapt many parameters simultaneously with a computational cost equivalent to that of the simple GA. A‐SAIGA improves exploration speed by avoiding synchronization between islands.Throughout our evaluation experiments, we confirmed that the performance of these GAs is close to that of the simple GA with optimal parameters. We also confirmed that A‐SAIGA outperforms SAIGA in exploration speed. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(14): 25–33, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20635
Toxicity of azaarenes in bacterial assays: Mechanistic studies
Authors: Catallo W. James , Portier Ralph J. , Gale Robert J. 
Published: October 2006

AbstractExposure of bacterial cells to selected azaarenes causes respiratory inhibition, membrane damage, decreased cellular ATP synthesis, and decreased cell viability. The purpose of this work was to examine the chemical mechanisms of acute toxicity of azaarenes and provide a preliminary model of azaarene cellular effects. Results of bioassays and in vitro spectrochemical and electrochemical experiments suggest that azaarenes alter membranes and electron transfer (ET) molecular assemblies primarily through noncovalent interactions not involving organic or oxy free radicals. The data suggest that membranes and membrane‐linked systems are altered via azaarene‐mediated chelation of divalent cations (Ca and Mg) found in the lipopolysaccharide matrix of the bacterial outer membrane. This gives rise to altered structure/function of periplasmic and inner membrane systems, and may contribute to changes in ET. Electrochemical analyses indicate that azaarenes also change the redox chemistry of flavin centers and seem to increase the ease with which ET processes occur between biochemical electron donors (NADH) and tetrazolium acceptors (iodonitrotetrazolium).
Fate and toxicity assessment of linear alkylbenzene sulfonates in drinking water using the ames test
Authors: Romera J. , Ventura F. , Caixach J. , Rivera J. , Guerrero R. 
Published: October 2006

AbstractThe genotoxic activity of the methanolic water extracts of prechlorinated water from Barcelona (NE Spain) using the Ames test was studied. High performance liquid chromatography (HPLC) and mass spectrometry in the mass spectroscopy/fast atom bombardment mode (MS/FAB) was employed to tentatively identify organic compounds responsible of genotoxic activity.Methanolic extracts of prechlorinated water were highly mutagenic in the Ames test, mainly with the TA98 strain for concentration lesser than 1 L. On the other hand, the TA100 strain showed higher mutagenicity for tap water extracts and concentrations higher than 1 L.Also, a strong toxic effect was observed when methanolic extracts were analyzed by the Ames test. Toxicity showed a reduction of the genotoxic ratio by a characteristic negative slope for the concentration vs genotoxicity curve. Toxicity was usually observed using the TAlOO strain and at a higher concentration than mutagenicity does. Both mutagenicity and toxicity in the Ames test showed a characteristic pattern depending on their origin (tap or prechlorinated water).It was possible to separate mutagenic from toxic fractions by HPLC. These subfractions were analyzed by MS/FAB in order to identify the organic compounds responsible for these effects, but unsuccessful results were obtained for mutagenic subfractions.Alkylbenzenesulfonates (LA3) were the sole compounds identified in toxic subfractions. The correlation between toxicity of samples (TA100 strain) and the presence of LAS was proved by comparison of toxicity from a standard LAS and those observed from real samples. An EC 50 of 9.8 mg/L for LAS has been established by the Ames test using the TAlOO strain. © 1993 John Wiley & Sans, Inc.
Comparative assessment of the SOS Chromotest kit and the Mutatox test with the Salmonella plate incorporation (Ames test) and fluctuation tests for screening genotoxic agents
Authors: Legault R. , Blaise C. , Rokosh D. , Chong‐Kit R. 
Published: October 2006

AbstractGenuine needs for rapid, simple, and cost‐efficient biotesting procedures to screen an ever‐increasing number of chemicals and environmental samples are making the search for such assays a constant endeavor. With respect to genotoxicity screening, we compared, in this study, the performance of two novel assays (Vibrio fischeri M169 Mutatox™ assay and the Escherichia coli PQ37 SOS Chromotest kit assay) with two well‐established Ames testing procedures (plate incorporation and fluctuation assays). Testing material included 14 chemicals (10 potentially directly acting and 4 indirectly acting compounds) reflecting different chemical classes (2 inorganics, 2 pesticides, 2 halogenated hydrocarbons, 2 alkylating agents, 2 aromatic amines, 1 chlorophenol, and 3 polycyclic aromatic hydrocarbons). Comparative assessment criteria included (1) interprocedural agreement in detecting presence or absence of genotoxicity, (2) accuracy in being able to recognize animal (non)carcinogens, and (3) sensitivity (detection of lowest actively genotoxic concentration). In terms of qualitative responses, both the SOS Chromotest (86% agreement) and Mutatox assays (93% agreement) were good predictors of the Ames testing mutagenicity. For their capability to correctly discriminate between (non)carcinogens, accuracy was 82% (9 of 11 chemicals) for Mutatox, 73% (8 of 11 chemicals) for Ames testing, and 64% (7 of 11 chemicals) for the SOS Chromotest. In general, the Salmonella‐based assays proved more sensitive (6 times out of 9 chemicals) than the Mutatox (3 times out of 9 chemicals) and the SOS Chromotest (never more sensitive). Overall, this study demonstrates reliable performances by both the SOS Chromotest and Mutatox for chemical genotoxicity screening when results are referenced to the well‐validated Ames assay. Although additional comparative data with other chemicals will be required, it appears likely that these more practical and cost‐efficient procedures can be presently useful to screen genotoxic activity of various xenobiotics and environmental samples. © 1994 by John Wiley & Sons, Inc..
Paper as reference material in “Sturm test” applied to insoluble substances
Authors: Musmeci L. , Gucci P. M. B. , Volterra L. 
Published: October 2006

AbstractThe ever‐increasing use of plastics for the packaging, wrapping, and transportation of goods is causing serious concern in regard to their environmental fate when they are carelessly discarded (visual pollution), or disposed off by dumping or by incineration.For this reason in the last few years in Italy legislation was introduced, specif ing that the plastics used in the manufacturing of shopping bags must be “biodegradable.” The selected test for assaying biodegradability was the modified Sturm method. In applying this assay the choice of reference standard materials, which associates two characteristics—biodegradability and insolubility—is a major problem.The possibility was investigated of utilizing a paper sample.The modified Sturm method revealed that the biodegradability of six paper samples varied from 54.5 to 75.2%; papers of two shopping bags showed a biodegradadability of 48.0 and 95.0%, respectively. The variability in the results was due to the composition of the paper.Results from this study indicate that the kind of paper to be used as reference material in the modified Sturm method has to be strictly selected in order to guarantee the reproducibility of the measures. © 1994 by John Wiley & Sons, Inc..
Studies on Bacillus thuringiensis H‐14 strains isolated in Egypt. VII. Toxicity to insecticide resistant and susceptible strains of mosquitoes
Authors: Abdel‐Hameed A. , Leake C. , Carlberg G. , Niemelä S. I. , El‐Tayeb O. M. 
Published: October 2006

AbstractTwo strains of Bacillus thuringiensis H‐14 (M1 and S128) isolated in Egypt were bioassayed in the laboratory against various insecticide‐susceptible and ‐resistant mosquito species and strains. The results for both bacterial strains tested against Aedes (4 strains), Culex (4 strains), and Anopheles (7 strains) larvae indicate a wide spectrum of larvicidal activity within the Culicidae. Generally, fourth instar larvae of the Aedes and Culex strains were found to be more susceptible than third instar larvae of Anopheles strains. In addition, mosquito strains within the same species that have different geographical origins and/or resistance patterns to residual insecticides were found to have different susceptibilites to the tested preparations. No apparent relationship was found between resistance to insecticides in these mosquito strains and their susceptibility to the tested preparations of B. thuringiensis H‐14. These data indicate that B. thuringiensis H‐14 could be of potential use against insecticide‐resistant vector populations in integrated disease‐control programs. © 1994 by John Wiley & Sons, Inc..
Toxicity of the blue‐green alga (cyanobacterium) Microcystis aeruginosa in drinking water to growing pigs, as an animal model for human injury and risk assessment
Authors: Falconer Ian R. , Burch Michael D. , Steffensen Dennis A. , Choice Mandy , Coverdale O. Robert 
Published: October 2006

AbstractHepatotoxins from blue‐green algae are increasingly recognized as a potential hazard in drinking water supplies. The clinical consequences of ingestion include acute or chronic liver injury, with the possibility of enhanced susceptibility to, and growth of, liver tumors. To establish guidelines for water safety requires the demonstration of dose‐dependent effects of toxicity and experimental determination of maximum “no‐adverse‐effect levels.” This paper describes the use of growing pigs as a model for human injury resulting from Microcystis toxins in drinking water. Risk assessment calculations using a series of safety factors are carried out, resulting in a guideline level after incorporating an additional safety factor for tumor promotion of approximately 1.0 μg toxins/L. With the Microcystis used for this trial, that concentration corresponds to 5000 cells/mL. © 1994 by John Wiley & Sons, Inc..
Derivation of water quality objectives for hazardous substances to protect aquatic ecosystems: Single‐species test approach
Authors: Schudoma Dieter 
Published: October 2006

AbstractTwo methodological approaches used to derive quality objectives to protect aquatic communities based on single‐species tests will be described. Water quality objectives to protect aquatic life may be derived on the basis of ecotoxicological tests considering toxicity to bacteria, algae, (small) crustaceans, and fish. This spectrum of species comprises representatives of four trophic levels of water biocoenosis. The lowest no observed effect concentration value of the most sensitive specie is reduced by a safety factor (more appropriate: uncertainty factor) to extrapolate a “safe level” for the aquatic ecosystem. An alternative approach is the use of statistical extrapolation methods based on species sensitivity distributions to calculate maxium permissible concentrations. The approach using uncertainty factors will be compared with the approach using species sensitivity distribution to extrapolate safe levels. ©1994 by John Wiley&Sons, Inc..
Cyst‐based ecotoxicological tests using Anostracans: Comparison of two species ofStreptocephalus
Authors: Crisinei A. , Delaunay L. , Rossel D. , Tarradellas J. , Meyer H. , Saïah H. , Vogel P. , Delisle C. , Blaise C. 
Published: October 2006

AbstractCyst‐based ecotoxicological tests are simple and low‐cost methods for assessing acute toxicity. Nevertheless, only a few comparative studies on their sensitivity are known. In the present study, the suitability of the use of two freshwater Anostracan species,Streptocephalus rubricaudatusandS. texanus, was assessed. The impact of 16 priority pollutants (4 heavy metals, 11 organic, and 1 organometallic compounds) on these two species, as well as onArtemia salina(Artoxkit M),Daphnia magna(International Organization for Standardization 6341), andS. proboscideus(Streptoxkit F) was assessed. For indicative comparison, bioassays usingBrachionus calyciflorus(Rotoxkit F) andPhotobacterium phosphoreum(Microtox) were also performed.For heavy metals (K2Cr2O7, Cd2+, Zn2+, Cu2+), the sensitivity of the two studiedStreptocephalusspecies was slightly higher than that ofD. magna.It was significantly more elevated than for the marineA. salina. For organic and organometallic micropollutants [phenol, 3,5‐dichlorophenol, pentachlorophenol (PCP), hydroquinone, linear alkylbenzene sulfonate, sodium dodecyl sulfate, tributylphosphate, dimethylphthalate, atrazine, lindane, malathion, tributyltin chloride (TBT‐CI)], the sensitivity of the 4 anostracan species was of the same order of magnitude as that ofD. magna. Artemia salinawas slightly less sensitive to some organic compounds (PCP, hydroquinone, TBT‐CI).The sensitivity ofS. rubricaudatusto organic solvents was low. On the other hand, this anostracan was quite sensitive to NaCI. Thus, its use is restricted to freshwater samples.The evaluation of global practicability of these two tests confirms that cyst‐based freshwater anostracans may be used to perform low‐cost tests at a sensitivity comparable to that ofD. magna(24 h immobilization test). ©1994 by John Wiley&Sons, Inc..
Rapid methods to assess the effects of chemicals on microbial activity in soil
Authors: Haigh S. D. , Rennie A. F. K. 
Published: October 2006

AbstractFluorescein diacetate (FDA) hydrolysis and an automated bacterial impedance technique (RABIT) were compared to the Pseudomonas putida growth inhibition assay (PGI) to assess their suitability as rapid methods to screen for effects of chemicals on soil microbial activity.RABIT was rapid, was the simplest, and was most convenient of the three methods to perform, but it was an order of magnitude less sensitive to toxicity than FDA or PGI. Further modification of the method may result in a most useful tool for screening purposes.The FDA hydrolysis method was both simple and rapid to perform. It gave comparable results to the PGI method for 3,5‐dichlorophenol and an amphoteric surfactant, but FDA was an order of magnitude more sensitive to the anionic and nonionic and an order of magnitude less sensitive to the cationic surfactants tested. This apparent conflict emphasizes that the toxicity assessment of a chemical in the environment should not rely entirely on inherent toxicity tests. For terrestrial toxicity testing, interactions between chemical and soil should be taken into account in order to predict correctly the chemical's impact on the environment. For example, adsorption of cationics onto soil particles results in significantly higher concentrations of the chemical being needed in vivo to cause a toxic effect than that predicted by inherent toxicity tests.The use of soil suspensions in the FDA assay, rather than pure cultures of microorganisms, is a more realistic, but still indirect, test of a chemical's toxicity in soil. When the assay is calibrated against a standard method, such as PGI using uncharged reference chemicals, this method can provide a simple and rapid tool to assess the relative effects of chemicals on soil microbial activity. © 1994 by John Wiley & Sons, Inc..
A simple technique for monitoring mutagenicity and benzo(a)pyrene content in mussels and their ambient water
Authors: Kira Shohei , Taketa Kazuhisa , Nogami Yusaku , Hayatsu Hikoya 
Published: October 2006

AbstractBy hanging blue rayon, an adsorbent specific for chemicals with polycyclic aromatic structures, in seawater for one day, the mutagenicity and the benzo(a)pyrene pollution of the water were monitored. Mussels living in the sites of water sampling were also subjected to the blue rayon extraction process and assayed. The mutagenicity was evaluated by the Salmonella/microsome reversion assay of Ames, with the use of a recently developed sensitive strain YG1024. The monitoring was performed in the Seto Inland Sea at 5 sites near Okayama, in the year 1991–1992. All the water and mussel samples gave positive benzo(a)pyrene contents and many of them showed positive mutagenicity (as assayed with metabolic activation). The mutagenicity and the benzo(a)pyrene contents were found to be significantly correlated both for the water samples and for the mussel samples. In contrast, there were no correlations between the water and the mussel samples regarding either the mutagenicity or benzo(a)pyrene contents. This lack of correlations may be attributed to the fact that the water samples gave results for a one‐day exposure whereas the mussel samples gave those of a long‐term exposure. This simple technique has advantages over the conventional sampling method in terms of easy handling, high sensitivity, and feasibility of monitoring distant sites. © by John Wiley & Sons, Inc.
Quantitative assessment of herbicide decomposition at different initial concentrations
Authors: Stenström John 
Published: October 2006

AbstractThe validity of the equation for first‐order kinetics and of the empirical equation c = c0 ‐ kt1/2 was checked against experimental data on the decomposition of the herbicides linuron and atrazine at different initial concentrations c0, in soil. Standard statistical criteria showed acceptable fits to the data according to first‐order kinetics, but the more stringent criterion of independence of the first‐order rate constant on c0 proved this kinetics to be invalid. The empirical equation gave a better fit to the data. Furthermore, the rate constant k varied linearly with c0 at low c0 and with c1/20 at high c0. Similar relations between k and c0 were also found with 14C‐labeled linuron, when it was found that the curve describing the collected amount of 14C in CO2 consisted of more than one phase. The empirical equation can thus be used to assess quantitatively the influence of various factors on the degradation, using both unlabeled and 14C‐labeled substances.
Anaerobic subsurface soil microcosms: Methods to monitor effects of organic pollutants on indigenous microbial activity
Authors: Dougherty Joel M. , Lanza Guy R. 
Published: October 2006

AbstractWe report the results of an experiment designed to study the effects of organic pollutants on microbial populations indigenous to subsurface soil. Subsurface soil from a pristine short grass prairie, collected aseptically and anaerobically, was used to construct microcosms. The microcosms were divided into three groups: control, biotic chemical, and abiotic chemical. The chemical groups received additions of three organic pollutants in varying concentrations: phenothiazine, chloronapthalene, and polychlorinated biphenyl. The microbial activity of the abiotic chemical group was inhibited with mercuric chloride. The control group received only water. Microbial activity was monitored in all groups using several enzyme assays and a biomass estimate: amylase, dehydrogenase, esterase, phosphatase, protease, and soil protein concentration. Eh and pH were also monitored. Throughout the 32 weeks, overall reducing conditions prevailed in the biotic chemical and control groups. The Eh of the abiotic group remained high. Significant differences were seen among groups in specific enzymatic activities on specific sample dates. However, fluctuating values through time due to succession of microbial consortia made it impossible to make predictions about the overall effects of the pollutants on individual activity measurements. This study is the first report of the effects of a mixture of organic pollutants on microbial consortia indigenous to subsurface soils.
Influence of sulfooxyanions on oxygen uptake, carbon dioxide fixation, and cytochrome reduction in Nitrobacter Agilis
Authors: Tsai Yu‐Li , Tuovinen Olli H. 
Published: October 2006

AbstractOxygen uptake coupled with nitrite oxidation by washed cell suspensions was not influenced by persulfate or tetrathionate. Carbon dioxide fixation was insensitive to tetrathionate, and in fact, an enhancement by tetrathionate was observed. Persulfate inhibited the fixation of carbon dioxide only at a high concentration (17 mM S2O2−8). Cytochrome reduction in washed cells of Nitrobacter agilis was demonstrated in the presence and absence of sulfooxyanions. Cytochrome aa3 and cytochrome a1 (α‐peak at 590 nm) were sensitive to sulfooxyanions (sulfite, thiosulfate, metabisulfite, dithionate, persulfate, trithionate, and tetrathionate), whereas cytochrome c (β‐peak at 520 nm) was insensitive to test ions. All sulfooxyanions inhibited the reduction of cytochrome a1 (γ‐peak at 438 nm). This inhibition decreased when the concentration of sulfooxyanions was increased to 17 mM. The reduction of cytochrome c at 550 nm (α‐peak) was blocked by the test ions and the inhibition of cytochrome c at 415 nm (γ‐peak) was also apparent. Complete inhibition of cytochrome c (γ‐peak) was observed in the presence of 17 mM persulfate.