bluuebunny/crossref_metadata_2025_split huggingface dataset:
An assessment of the application factor used to derive the saltwater acute ambient water quality copper criterion
Authors: Arnold W Ray , Cotsifas Jeffrey S 
Published: June 2008

Abstract
The basis for all US Environmental Protection Agency (USEPA) acute ambient water quality criteria is the chemical specific final acute value (FAV; an estimate of the concentration of the chemical corresponding to a cumulative probability of 0.05 of acute toxicity values for all genera with which acceptable acute tests have been conducted). The acute criterion for all chemicals is equal to the chemical's FAV divided by an application factor of 2. The intention of dividing the FAV by a factor of 2 is to convert the acute toxicity value to an incipient acute toxicity value, resulting in an acute criterion concentration that will protect against toxic effects to aquatic organisms. In the case of copper (Cu) in saltwater, the FAV is reduced from the normal 0.05 probability to equal to the genus mean acute value (GMAV; the geometric mean of copper effect concentration 50% [EC50] values) of the economically important marine bivalves of the genus Mytilus. Analyses to determine an application factor specific to Mytilus and copper were performed to assess the adequacy of the application factor of 2. An estimate of a dissolved copper application factor that is specific to and protective of Mytilus was determined using the results of sixty-four 48-h embryo survival and shell development copper toxicity tests of natural water samples collected from sites around the United States. A variety of point-estimate effects concentrations (EC1, EC5, EC10, EC20, and chronic values [ChV]) and statistical toxic-effect endpoints (no observed effect concentration [NOEC] and lowest observed effect concentration [LOEC]) were derived from the test results and compared. The most similar toxic effect endpoint estimates were EC1 ≈︁ NOEC, EC10 ≈︁ ChV, and EC20 ≈︁ LOEC. Probabilistic methods were used to determine a specific application factor with a high probability of providing protection. This analysis suggests that an application factor of 1.5 (rather than 2) is adequate to provide a high degree of protection against acute effects of dissolved copper to Mytilus. In context, this translates to an acute saltwater dissolved copper criterion of 6.4 μg Cu/L compared to the current acute criterion of 4.8 μg Cu/L.
Critical evaluation of the sediment effect concentrations for polychlorinated biphenyls
Authors: Becker D Scott , Ginn Thomas C 
Published: June 2008

Abstract
In 2000, a set of sediment effect concentrations (SECs) was published for evaluating the toxicity of polychlorinated biphenyls (PCBs) in freshwater, estuarine, and marine sediments. According to the developers, these consensus-based SECs reconcile existing sediment quality guidelines (SQGs) that have been developed using various approaches, reflect causal rather than correlative effects, and can be used to determine the spatial extent of injury to sediment-dwelling organisms. In the present study, a critical evaluation of the SECs was conducted based on the original documents and databases used to develop the underlying SQGs for the SECs, as well as the original documents and data sets used to determine the predictive ability of the SECs. Results of the critical evaluation indicated that the SECs are simple mathematical constructs that share the same limitations as their underlying SQGs. The SECs are questionable “consensus” values, because many of their underlying SQGs are dissimilar, misclassified, or redundant with other SQGs. Because nearly all of the data sets included in the databases used to calculate the underlying SQGs, or to validate the SECs, were affected by elevated concentrations of multiple co-occurring chemicals, it was not possible to conclusively identify PCBs as the cause of any of the observed sediment toxicity. The SECs, and most of their underlying SQGs, are likely biased by the fact that their underlying databases are composed primarily of PCB concentrations less than 0.5 mg/kg dry weight. Comparisons between the SECs and bioaccumulation-based SQGs calculated using the equilibrium partitioning approach provide no information on whether the SECs are causally related to sediment toxicity. The primary available median lethal concentration (LC50) value for PCBs, determined using spiked-sediment toxicity tests, has limited applicability to most contaminated aquatic environments, because it was determined using an unusually low total organic carbon content. Finally, site-specific application of the SECs indicated that their predictive ability was very low, that concentration-response relationships were not found for a variety of test species and toxicity endpoints at PCB concentrations greater than the SECs, and that some of the highest survival and growth values in the toxicity tests were found at PCB concentrations considerably greater than the SECs. Based on the results of this study, we conclude that the SECs for PCBs should be used only in the screening-level evaluations that typically precede more direct assessments of sediment toxicity at individual study sites, and should not be used to predict the presence of sediment toxicity. Contrary to the conclusions of the SEC developers, the SECs do not reconcile existing SQGs, do not reflect causal effects, and should not be used to determine the spatial extent of injury to sediment-dwelling organisms.
Comparison of a score-based approach with risk-based ranking of in-use agricultural pesticides in canada to aquatic receptors
Authors: Whiteside Mélanie , Mineau Pierre , Morrison Clare , Knopper Loren D 
Published: June 2008

Abstract
The purpose of this paper is to present a new risk-based approach developed by Environment Canada for ranking pesticides and their potential risk to aquatic life. These rankings are compared to those generated using a more traditional score-based approach. Two hundred and twelve active ingredients registered in Canada for use in agricultural field crops were included in this assessment. For each major aquatic taxon assessed (fish, insects, crustaceans, algae, and macrophytes), risk was calculated by dividing the 96-h estimated environmental concentration (modeled using parameters such as the application rate and method as well as physicochemical properties) by HC5 values (obtained through calculations of species sensitivity distribution — based toxicity endpoints). The traditional approach assigned scores based on toxicity endpoints in standard test species as well as physicochemical properties associated with the potential for aquatic contamination. A number of similarities were observed between the rankings but also notable differences. Only 22 active ingredients were common to the top 50 ranking positions from both approaches. The main reasons that accounted for the discrepancies between both rankings were the choice of toxicity endpoints, whether based on single or multiple species; the taxonomic breadth of retained data; the use of scores versus risk quotients; and the choices made in situations where multiple data points were available. We conclude that a risk-based approach that considers a broad representation of species toxicity data and estimates of runoff and drift concentration in receiving aquatic systems (even from generic application scenarios) is a more realistic representation of potential toxicological effects and a superior method of ranking products for the risk they pose to the aquatic environment.
Assessing the Combined Impact of 18 Common Genetic Variants of Modest Effect Sizes on Type 2 Diabetes Risk
Authors: Lango Hana ,   the U.K. Type 2 Diabetes Genetics Consortium, Palmer Colin N.A. , Morris Andrew D. , Zeggini Eleftheria , Hattersley Andrew T. , McCarthy Mark I. , Frayling Timothy M. , Weedon Michael N. 
Published: June 2008

OBJECTIVES—Genome-wide association studies have dramatically increased the number of common genetic variants that are robustly associated with type 2 diabetes. A possible clinical use of this information is to identify individuals at high risk of developing the disease, so that preventative measures may be more effectively targeted. Here, we assess the ability of 18 confirmed type 2 diabetes variants to differentiate between type 2 diabetic case and control subjects.
RESEARCH DESIGN AND METHODS—We assessed index single nucleotide polymorphisms (SNPs) for the 18 independent loci in 2,598 control subjects and 2,309 case subjects from the Genetics of Diabetes Audit and Research Tayside Study. The discriminatory ability of the combined SNP information was assessed by grouping individuals based on number of risk alleles carried and determining relative odds of type 2 diabetes and by calculating the area under the receiver-operator characteristic curve (AUC).
RESULTS—Individuals carrying more risk alleles had a higher risk of type 2 diabetes. For example, 1.2% of individuals with &gt;24 risk alleles had an odds ratio of 4.2 (95% CI 2.11–8.56) against the 1.8% with 10–12 risk alleles. The AUC (a measure of discriminative accuracy) for these variants was 0.60. The AUC for age, BMI, and sex was 0.78, and adding the genetic risk variants only marginally increased this to 0.80.
CONCLUSIONS—Currently, common risk variants for type 2 diabetes do not provide strong predictive value at a population level. However, the joint effect of risk variants identified subgroups of the population at substantially different risk of disease. Further studies are needed to assess whether individuals with extreme numbers of risk alleles may benefit from genetic testing.
Structural and optical properties of layers of pentacene formed by PLD method
Authors: Potera Piotr , Sagan Piotr , Virt Ihor , Kuzma Marian , Wisz Grzegorz , Rudyj Ihor , Frugynski Marian 
Published: June 2008

Abstract
Organic films fabrication offers the possibility of producing electronic devices of low weight, mechanical flexibility and low cost. One suitable material for organic film fabrigation which is the subject of the great interest is pentacene, because it is characterized by the large carrier mobility (∼1 cm2/Vs).
In this work, the growth of pentacene layers using pulse laser deposition (PLD) on different substrates (glass/ITO, Si) is described and various processing parameters are investigated. Two pulsed YAG:Nd3+ laser wavelengths were used for the ablation of the PLD target: the first harmonic at 1064 nm aGn:dNdth3+e second at 532 nm. The structure of the layers formed was examined using SEM and RHEED methods. The results were compared with results of optical spectroscopy studies. It will be shown that layers deposed using second harmonics have a higher quality than those for first harmonic. The other PLD parametersalso have a strong influence on the structure quality of layers.
Comparison of different technologies for alginate beads production
Authors: Prüsse Ulf , Bilancetti Luca , Bučko Marek , Bugarski Branko , Bukowski Jozef , Gemeiner Peter , Lewińska Dorota , Manojlovic Verica , Massart Benjamin , Nastruzzi Claudio , Nedovic Viktor , Poncelet Denis , Siebenhaar Swen , Tobler Lucien , Tosi Azzurra , Vikartovská Alica , Vorlop Klaus-Dieter 
Published: June 2008

AbstractThis paper describes the results of the round robin experiment “Bead production technologies” carried out during the COST 840 action “Bioencapsulation Innovation and Technologies” within the 5th Framework Program of the European Community. In this round robin experiment, calcium alginate hydrogel beads with the diameter of (800 ± 100) μm were produced by the most common bead production technologies using 0.5–4 mass % sodium alginate solutions as starting material. Dynamic viscosity of the alginate solutions ranged from less than 50 mPa s up to more than 10000 mPa s. With the coaxial air-flow and electrostatic enhanced dropping technologies as well as with the JetCutter technology in the soft-landing mode, beads were produced from all alginate solutions, whereas the vibration technology was not capable to process the high-viscosity 3 % and 4 % alginate solutions. Spherical beads were generated by the electrostatic and the JetCutter technologies. Slightly deformed beads were obtained from high-viscosity alginate solutions using the coaxial airflow and from the 0.5 % and 2 % alginate solutions using the vibration technology. The rate of bead production using the JetCutter was about 10 times higher than with the vibration technology and more than 10000 times higher than with the coaxial air-flow and electrostatic technology.
Synthesis and characterization of diaminomaleonitrile-functionalized polystyrene grafts for application in pervaporation separation
Authors: Abdel-Razik Hamada 
Published: June 2008

AbstractSynthesis, characterization and application of diaminomaleonitrile (DAMN)-functionalized polystyrene grafts were studied. Dibenzoyle peroxide (BP) was used as an initiator. Optimum conditions for grafting were found to be c(DAMN) = 0.5 M, c(BP) = 0.016 M, θ = 85 °C and t = 4 h. Water uptake of the polystyrene graft membranes was found to increase with the increase of the grafting yield. The chemical structure, thermal characteristics and thermal stability of the obtained membranes were investigated by means of FTIR spectroscopy, differential scanning calorimetry, and thermal gravimetric analysis. Polystyrene graft membrane with the degree of grafting of up to 96 % was found to be useful for the pervaporation separation of phenol/water mixtures.
Alkalimetric determination of hydrophobic pharmaceuticals using stabilized o/w emulsions
Authors: Shevchenko Ganna , Kulichenko Sergey 
Published: June 2008

AbstractProtolytic properties of (+)-(S)-2-(6-methoxynaphthalen-2-yl)propanoic acid (naproxen), 2-(3-benzoylphenyl)propionic acid (ketoprofen), 4-chloro-N-(2-furylmethyl)-5-sulfamoylanthranilic acid (furosemide), and N-(2,3-dimethylphenyl)anthranilic acid (mefenamic acid) in “oil-in-water” emulsions stabilized by surfactants were studied. The procedures for alkalimetric determination of naproxen, ketoprofen, furosemide, and mefenamic acid in emulsion media with indication of the equivalence point pH-metrically and with the use of indicators were proposed.
Preparation of nanocrystalline anatase TiO2 using basic sol-gel method
Authors: Bi-Tao Xiong , Bao-Xue Zhou , Long-Hai Li , Jun Cai , Yan-Biao Liu , Wei-Min Cai 
Published: June 2008

AbstractNanocrystalline titanium dioxide particles with anatase structure and high thermal stability have been synthesized using the basic sol-gel method. The particle size and morphology were refined under hydrothermal conditions in the presence of different concentrations of tetramethylammonium hydroxide (TMAH) at 210°C and 230°C. XRD and TEM analysis showed that the TiO2 particles obtained were homogeneous and monodispersive at low contents of TMAH. All intense peaks, clearly observed in the XRD patterns, were assigned to the anatase phase and no rutile phase was observed. At high contents of TMAH, nanoscale small (10–30 nm) and larger (>100 nm) TiO2 particles were one-pot synthesized. The nanocrystalline TiO2 particles synthesized by this method have good thermal stability. With the sintering temperature of up to 650°C, all the XRD peaks maintained good agreement with the anatase reference data.
Extraction and analysis of ellagic acid from novel complex sources
Authors: Aguilera-Carbo Antonio , Augur Christopher , Prado-Barragan Lilia , Aguilar Cristóbal , Favela-Torres Ernesto 
Published: June 2008

AbstractEllagic acid (EA) was quantified by reversed-phase high-performance liquid chromatography (RPHPLC) coupled with photodiode array detection (DAD) in five fine-powdered plants collected from the semiarid region of Mexico. Samples analysed included Jatropha dioica branches (Dragon’s blood), Euphorbia antisyphyllitica branches (Candelilla), Turnera diffusa Willd leaves (Damiana), Flourensia cernua leaves (hojasén) and Punica granatum husk (pomegranate) at two maturity stages (“turning” or intermediate and maturated fruit, considered as positive controls). The results demonstrated high EA concentrations in all tested samples which are novel sources of this natural antioxidant. The method developed for the EA analysis is fast and it showed an excellent linearity range, repeatability, intra-and inter-day precision and accuracy with respect to the methods reported for the EA analysis.
3,5-Bis(2-hydroxyphenyl)-1H-1,2,4-triazole based ligands — protonation and metal complex formation
Authors: Stucky Stefan , Koch Nadine , Heinz Uwe , Hegetschweiler Kaspar 
Published: June 2008

Abstract3,5-Bis(2-hydroxyphenyl)-1H-1,2,4-triazole (H2La) and 4-[3,5-bis(2-hydroxyphenyl)-1H-1,2,4-triazol-1-yl]benzoic acid (H3Lb) have been prepared, and crystal structure of the intermediate 2-(2-hydroxyphenyl)-4H-1,3-benzoxazin-4-one has been determined. Temperature dependent 1H NMR spectroscopic measurements of H2La indicated dynamic behavior with the equilibrium between the two asymmetric tautomers. For H3Lb, pD-dependent 1H NMR spectroscopic measurements showed small but characteristic shifts in the range of 0 ≤ pD ≤ 1, indicative of a triazole nitrogen atom protonation; the corresponding pK a of 0.98 ± 0.04 was determined by spectrophotometric titrations. (H2O, 26°C, 1 M KCl/HCl). Formation of [FeIII(La)]+ (pH 2.5) and [FeIII(La)2]− (pH > 6) was verified by UV-Vis spectroscopy. Complex formation of H3Lb with Al3+ and VO2+ was investigated by 1H NMR spectroscopic titration and cyclic voltammetry, respectively. Single crystals of the phenoxo bridged [VVO(HLb)(EtO)]2·2EtOH were characterized by X-ray structural analysis.
Synthesis, crystal structure, and magnetic properties of a cobalt(II) complex with (3,5-dichloropyridin-4-yl)(pyridin-4-yl)methanol
Authors: Zhu Zhicheng , Mikuriya Masahiro 
Published: June 2008

AbstractA novel bridging ligand, (3,5-dichloropyridin-4-yl)(pyridin-4-yl)methanol (I), and its cobalt(II) complex, [Co(I)2(NCS)2]n (II), were prepared. The structures of ligand I and complex II were determined by single crystal X-ray analysis. Magnetic susceptibility measurements were performed for cobalt (II) complex II. Compound I crystallised in orthorhombic space group Pbca with a = 7.6585(14) Å, b = 12.209(2) Å, c = 23.207(4) Å, V= 2170.0(7) Å3 and Z=8. Complex II crystallised in monoclinic space group P21/n with a = 13.223(8) Å, b = 16.959(10) Å, c = 13.948(8) Å, β = 115.395(10)°, V= 2826(3) Å3 and Z = 4. Each cobalt(II) ion is surrounded by two NCS− anions and four pyridyl moieties from two bridging ligands. Each bridging ligand connects two neighbouring Co(II) ions to form a 2-dimensional structure. Temperature dependence of the molar magnetic susceptibilities in the temperature range of 2–300 K revealed that magnetic interactions between the cobalt ions are weak.
Preparation and modification of collagen-based porous scaffold for tissue engineering
Authors: Sloviková Alexandra , Vojtová Lucy , Jančař Josef 
Published: June 2008

AbstractIn the effort to generate cartilage tissues using mesenchymal stem cells, porous scaffolds with prescribed biomechanical properties were prepared. Scaffolds with interconnected pores were prepared via lyophilisation of frozen hydrogels made from collagen modified with chitosan nanofibres, hyaluronic acid, copolymers based on poly(ethylene glycol) (PEG), poly(lactic-co-glycolic acid) (PLGA), and itaconic acid (ITA), and hydroxyapatite nanoparticles. The modified collagen compositions were cross-linked using N-(3-dimethylamino propyl)-N′-ethylcarbodiimide hydrochloride (EDC) combined with N-hydroxysuccinimide (NHS) in water solution. Basic physicochemical and mechanical properties were measured and an attempt to relate these properties to the molecular and supermolecular structure of the modified collagen compositions was carried out. Scaffolds containing hydrophilic chitosan nanofibres showed the highest swelling ratio (SR = 20–25) of all the materials investigated, while collagen modified with an amphiphilic PLGA-PEG-PLGA copolymer or functionalised with ITA exhibited the lowest swelling ratio (SR = 5–8). The best resistance to hydrolytic degradation was obtained for hydroxyapatite containing scaffolds. On the other hand, the fastest degradation rate was observed for synthetic copolymer-containing scaffolds. The results showed that the addition of hydroxyapatite or hyaluronic acid to the collagen matrix increases the rigidity in comparison to the collagen-chitosan scaffold. Collagen scaffold modified with hyaluronic acid presented reduced deformation at break while the presence of hydroxypatatite enhanced the scaffold deformation under tensile loading. The tensile elastic modulus of chitosan nanofibre collagen scaffold was the lowest but closest to the articular cartilage; however, the strength and deformation to failure increased up to 200 %.
Synthesis, characterization, fluorescence and redox features of new vic-dioxime ligand bearing pyrene and its metal complexes
Authors: Yilmaz Ismail , Kilic Ahmet , Yalcinkaya Hacer 
Published: June 2008

AbstractA new vic-dioxime ligand, N,N′-bis(aminopyreneglyoxime) (LH2), and its copper(II), nickel(II) and cobalt(II) metal complexes were synthesized and characterized by elemental analyses, IR, UVVIS and 1H and 13C NMR spectra (for the ligand). Mononuclear complexes were synthesized by a reaction of ligand (LH2) and salts of Co(II), Ni(II), and Cu(II) in ethanol. The complexes have the metal-ligand ratio of 1: 2 and metals are coordinated by N,N′ atoms of vicinal dioximes. The ligand acts in a polydentate fashion bending through nitrogen atoms in the presence of a base, as do most vic-dioximes. Detection of a H-bonding in the Co(II), Ni(II), and Cu(II) complexes by IR revealed the square-planar MN4 coordination of mononuclear complexes. Fluorescent properties of the ligand and its complexes arise from pyrene units conjugated with a vic-dioxime moiety. Fluorescence emission spectra of the ligand showed a drastic decrease in its fluorescence intensity upon metal binding. The electrochemical properties of the complexes were studied by the cyclic voltammetry technique. The nickel complex displayed an irreversible oxidation process while the copper complex exhibited a quasi-reversible oxidation and reduction processes based on the copper Cu(II)/Cu(III) and Cu(II)/Cu(I) couples, respectively.
Sensitive determination of nitrogenous hydrochloride drugs via their reaction with ammonium molybdate
Authors: Feng Suling , Guo Limin 
Published: June 2008

AbstractIn a hydrochloric acid medium, benzhexol hydrochloride, cyproheptadine hydrochloride, and maprotiline hydrochloride, can react with ammonium molybdate to form ion-association complexes by virtue of electrostatic attraction and hydrophobic interaction which result in a significant enhancement of the resonance light scattering intensity. The maximum scattering wavelengths were found at 364 nm, 364 nm, and 381 nm for benzhexol hydrochloride, cyproheptadine hydrochloride, and maprotiline hydrochloride systems, respectively. Spectral characteristics of the three systems, influencing factors, and optimum conditions were investigated. The reason of resonance light-scattering enhancement and the mechanism of interactions between the drugs and ammonium molybdate were also discussed. Based on the linear relationship between the enhanced intensity of resonance light scattering and the concentration of drugs, a highly sensitive method for the determination of the three drugs was developed, the detection limits being 0.0110 μmol L−1, 0.0038 μmol L−1, and 0.0155 μmol L−1 for benzhexol hydrochloride, cyproheptadine hydrochloride, and maprotiline hydrochloride, respectively. The method was successfully applied to the determination of the investigated drugs in pharmaceutical, serum, and urine samples.