bluuebunny/crossref_metadata_2025 huggingface dataset:
Ophthalmic delivery of sparfloxacin from in situ gel formulation for treatment of experimentally induced bacterial keratitis
Authors: Nesseem Demiana I.
Published: October 2010

The objective of the present work was (1) to develop an in situ gelling ophthalmic delivery system by combining pluronic F127 and pluronic F68, with sparfloxacin; and (2) to examine the influence of incorporating a mucoadhesive polysaccharide such as sodium hyaluronate on the healing property due to bacterial keratitis. The formulations (F1–F6) were sterilized by gamma irradiated using Co60. Ultraviolet (UV) and infrared (IR) spectra studies were performed on sterilized and non‐sterilized formulae. The formulations were evaluated for rheological characteristics, in vitro release behavior, and efficacy against induced bacterial conjunctivitis in rats' eyes. Moreover, histopathological evaluations were also done. All the samples passed sterility tests, and no change in physical appearance of the formulae due to gamma radiation was observed. The IR spectra of the formulae before and after sterilization showed similar peaks which confirmed that no ingredient was affected by gamma radiation. The formulations showed a flow index of 0.116–0.493 indicating pseudoplastic flow behavior. The release behavior of all formulae was non‐Fickian anomalous release. The different formulae used to overcome the pathological alterations, produced by bacteria infections varied among each other depending on the duration of treatment; however, the effectiveness of formulation was arranged as F5, F4 and F3, respectively. The developed formulations were therapeutically efficacious, and provided sustained release of the drug over a 24‐hour period. A better improvement in artificially induced bacterial conjunctivitis in rats' cornea was observed with the developed formulae; thus it can be considered as a viable alternative to conventional eye drops. Copyright © 2010 John Wiley & Sons, Ltd.
Experimental and spectroscopic studies of charge transfer reaction between sulfasalazine antibiotic drug with different types of acceptors
Authors: Refat Moamen S. , El‐Korashy Sabry A. , El‐Deen Ibrahim M. , El‐Sayed Shaima M.
Published: October 2010

The charge‐transfer (CT) interactions between the electron donor sulfasalazine (SS) and the acceptors 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ), p‐chloranil (CHL), picric acid (PA) and iodine have been studied spectrophotometrically in CHCl3 or CH3OH solutions. The formed solid CT complexes were also isolated and characterized through infrared, 1H‐NMR, mass spectra as well as elemental and thermal analysis. The CT complexes were discussed in terms of formation constant (KCT), molar extinction coefficient (εCT), standard free energy (ΔG°), oscillator strength (f), transition dipole moment (µ), resonance energy (RN) and ionization potential (ID). The stoichiometry of these complexes was found to be 1:1 molar ratio and having the formulae [(SS)(DDQ)], [(SS)(CHL)], [(SS)(PA)] and [(SS)2I]+· I3−, respectively. The charge transfer interaction was successfully applied to the determination of SS drug using mentioned σ and π‐acceptors also, the results obtained herein are satisfactory for estimation of SS compound in the pharmaceutical form. Copyright © 2010 John Wiley & Sons, Ltd.
A new validated ultra performance liquid chromatographic method for determination of acyclovir
Authors: Hasan S. , Chander P. , Ali J. , Baboota S. , Ali M.
Published: October 2010

Recently, ultra performance liquid chromatography (UPLC) has proven to be one of the most promising developments in the area of fast chromatographic separations, as it's been true to the objective of reducing analysis time and maintaining good efficiency. The present report describes development and validation of a new, rapid, and sensitive UPLC method with UV detection to quantify acyclovir in bulk sample using a Waters Acquity HSS T‐3 (100 × 2.1 mm, 1.8 µm) column maintained at a temperature of 50 °C with a gradient elution consisting of 1.0% triethyl amine in water and acetonitrile at a flow rate of 0.4 mL/min and detected at 254 nm. Method was found to be selective, linear, accurate, and precise as per ICH guidelines. Detection and quantitation limits of drug were 3 and 8 ng/mL, respectively. Copyright © 2010 John Wiley & Sons, Ltd.
Novel BN Hollow Microspheres with Open Mouths – Facile Synthesis, Growth Mechanism, Resonant Raman Scattering Effect, and Cathodoluminescence Performance
Authors: Wen Guangwu , Zhong Bo , Huang Xiaoxiao , Yu Hongming , Zhang Xiaodong , Zhang Tao , Bai Hongwei
Published: October 2010

Novel BN hollow microspheres have been successfully fabricated by a facile chemical vapour reaction approach using ammonia–borane as a precursor. The morphology and structure of the as‐synthesized products are characterized by scanning electron microscopy (SEM), high‐resolution transmission electron microscopy (HRTEM), selected‐area electron diffraction (SAED), as well as electron energy loss spectroscopy (EELS). The hollow microspheres have open mouths and are 0.5–6 μm in diameter. The walls of the hollow spheres with thicknesses ranging from 200 to 800 nm are composed of poorly crystallized BN. The growth mechanism of the hollow microspheres is investigated and a growth model is proposed. The BN hollow spheres show pronounced resonant Raman scattering character under illumination of a 457.9 nm laser line, which implies a potential photothermal effect. The hollow microspheres also exhibit intense cathodoluminescence emissions in the region of 200–400 nm, indicating that they could be potentially used as compact ultraviolet laser emitters. Moreover, the unique open‐mouth feature, in combination with the superior thermal and chemical stability of BN, makes the BN hollow microspheres potential candidates as microreactors for investigations of high‐temperature space‐confined chemical reactions.
Beyond Kahn's Model: Substituent and Heteroatom Influence on Exchange Interaction in a Metal‐Verdazyl Complex
Authors: Oms Olivier , Rota Jean‐Baptiste , Norel Lucie , Calzado Carmen J. , Rousselière Hélène , Train Cyrille , Robert Vincent
Published: October 2010

The synthesis, structure and magnetic properties of the first thiooxoverdazyl metal complex [Cu(hfac)2(Svdpy)] [hfac = (1,1,1,5,5,5)‐hexafluoroacetylacetonate; Svdpy = 1,5‐dimethyl‐3‐(2‐pyridyl)‐6‐thiooxoverdazyl] is described. The organic radical acts as a bidentate ligand leading to a six‐coordinate metal complex. The fit of the thermal variations of the magnetic susceptibility reveal a ferromagnetic intramolecular exchange interaction. This finding is confirmed and analysed by using wavefunction‐based methods which indicate that the exchange interaction is governed by the substituent of the radical rather than by its heteroatom.
Synthetic Approaches to Zigzag‐Shaped Oligophenylene Strands Laterally Decorated with Hydroxy Functions
Authors: Diebold Carine , Weekes David Michael , Torres Navarrete Maria , Mobian Pierre , Kyritsakas Nathalie , Henry Marc
Published: October 2010

Two nanosized zigzag‐shaped oligophenylene strands incorporating 2,2′‐biphenol units were prepared by Suzuki–Miyaura coupling methodology. The two strands are made up of ten and seven phenyl rings, respectively. Two synthetic pathways were evaluated. The first involved the preparation of the target oligophenylene molecules by a sequential approach, whereas the second entailed the formation of the precursors of the target compounds in a one‐step fashion. The efficiencies of these two approaches are discussed and compared.
Tp53 codon‐72 polymorphisms identify different radiation sensitivities to g2‐chromosome breakage in human lymphoblast cells
Authors: Schwartz Jeffrey L. , Plotnik David , Slovic Jana , Li Tiffany , Racelis Maximillian , Joachim Deeg H. , Friedman Debra L.
Published: October 2010

Both the G2 chromosomal radiosensitivity assay and allelic differences in TP53 codon‐72 have been associated with cancer predisposition. The relationship between the two endpoints was determined in 56 human EBV‐transformed lymphoblastoid cell lines. Although there were overlapping distributions of sensitivity for the different genotypes, cell lines that were homozygous for the proline coding allele were more likely to be resistant to chromatid break formation than those containing two arginine coding alleles, whereas cell lines expressing both the proline and arginine codon were either resistant like proline–proline lines or sensitive like arginine–arginine lines. The results support an important role of the TP53 codon‐72 polymorphism in modifying G2‐chromosome radiosensitivity. Distinguishing the effect of TP53 codon‐72 variations from other modifiers of G2‐chromosome radiosensitivity might aid in identifying new markers of cancer risk. Environ. Mol. Mutagen., 2010. © 2010 Wiley‐Liss, Inc.
Desorption of nitramine and nitroaromatic explosive residues from soils detonated under controlled conditions
Authors: Douglas Thomas A , Walsh Marianne E , McGrath Christian J , Weiss Charles A , Jaramillo Ashley Marie , Trainor Thomas P
Published: October 2010

Potentially toxic nitroaromatic and nitramine compounds are introduced onto soils during detonation of explosives. The present study was conducted to investigate the desorption and transformation of explosive compounds loaded onto three soils through controlled detonation. The soils were proximally detonated with Composition B, a commonly used military explosive containing 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). Gas-exchangeable surface areas were measured from pristine and detonated soils. Aqueous batches of detonated soils were prepared by mixing each soil with ultrapure water. Samples were collected for 141 d and concentrations of Composition B compounds and TNT transformation products 2-amino-4,6-dinitrotoluene (2ADNT), 4-amino-2,6-dinitrotoluene (4ADNT), and 1,3,5-trinitrobenzene (1,3,5-TNB) were measured. The RDX, HMX, and TNT concentrations in detonated soil batches exhibited first-order physical desorption for the first, roughly, 10 d and then reached steady state apparent equilibrium within 40 d. An aqueous batch containing powdered Composition B in water was sampled over time to quantify TNT, RDX, and HMX dissolution from undetonated Composition B particles. The TNT, RDX, and HMX concentrations in aqueous batches of pure Composition B reached equilibrium within 6, 11, and 20 d, respectively. Detonated soils exhibited lower gas-exchangeable surface areas than their pristine counterparts. This is likely due to an explosive residue coating on detonated soil surfaces, shock-induced compaction, sintering, and/or partial fusion of soil particles under the intense heat associated with detonation. Our results suggest that explosive compounds loaded to soils through detonation take longer to reach equilibrium concentrations in aqueous batches than soils loaded with explosive residues through aqueous addition. This is likely due to the heterogeneous interactions between explosive residues and soil particle surfaces. Environ. Toxicol. Chem. 2011;30:345–353. © 2010 SETAC
Using meiofauna to assess pollutants in freshwater sediments: A microcosm study with cadmium
Authors: Brinke Marvin , Ristau Kai , Bergtold Matthias , Höss Sebastian , Claus Evelyn , Heininger Peter , Traunspurger Walter
Published: October 2010

The direct and indirect effects of Cd on benthic communities were assessed in a freshwater microcosm study over a period of seven months (218 d). Cadmium was regarded as a model substance to evaluate the usefulness of small-scale laboratory microcosm with microscopic fauna. In particular, effects on the meiofauna community, an ecologically important but rather neglected benthic component, were investigated. In addition, some microfaunal parameters (protozoan abundance and microbial activity) were determined. The sediment was spiked with nominal Cd concentrations of 10, 100, and 1,000 mg/kg dry weight. Because of the strong binding of Cd to sediment particles, measured Cd pore-water concentrations never exceeded 129.5 ± 40.7 µg/L. At 1,000 mg/kg dry weight, the abundances of the two dominant meiofauna taxa, nematodes and oligochaetes, were significantly reduced throughout the present study. Regarding nematodes, species of bacterivorous taxa (Daptonema, Eumonhystera) decreased, whereas species of predacious and omnivorous taxa (Mononchus, Dorylaimus, and Ironus) increased in dominance in microcosms of the highest Cd concentration. Transient effects on microfauna were observed, especially in the first half of the present study, with a reduction in microbial activity and protozoan abundance. However, in microcosms receiving the highest Cd concentration, the abundance of the flagellate Euglena mutabilis increased significantly toward the end of the present study. The results of the present study support the use of small-scale microcosms with natural meiofauna communities as a suitable tool to assess the impact of pollutants in freshwater sediments. Environ. Toxicol. Chem. 2011;30:427–438. © 2010 SETAC
Screening complex effluents for estrogenic activity with the T47D-KBluc cell bioassay: Assay optimization and comparison with in vivo responses in fish
Authors: Wehmas Leah C , Cavallin Jenna E , Durhan Elizabeth J , Kahl Michael D , Martinovic Dalma , Mayasich Joe , Tuominen Tim , Villeneuve Daniel L , Ankley Gerald T
Published: October 2010

Wastewater treatment plant (WWTP) effluents can contain estrogenic chemicals, which potentially disrupt fish reproduction and development. The current study focused on the use of an estrogen-responsive in vitro cell bioassay (T47D-KBluc), to quantify total estrogenicity of WWTP effluents. We tested a novel sample preparation method for the T47D-KBluc assay, using powdered media prepared with direct effluent. Results of the T47D-KBluc assay were compared with the induction of estrogen receptor–regulated gene transcription in male fathead minnows (Pimephales promelas) exposed to the same effluents. Effluent samples for the paired studies were collected over the course of three months. According to the T47D-KBluc assay, the effluent estrogenicity ranged from 1.13 to 2.00 ng 17β-estradiol (E2) equivalents/L. Corresponding in vivo studies exposing male fathead minnows to 0, 10, 50, and 100% effluent dilutions demonstrated that exposure to 100% effluent significantly increased hepatic vitellogenin (VTG) and estrogen receptor α subunit transcripts relative to controls. The induction was also significant in males exposed to 250 ng E2/L or 100 ng E2/L. The in vitro and in vivo results support the conclusion that the effluent contains significant estrogenic activity, but there was a discrepancy between in vitro– and in vivo–based E2 equivalent estimates. Our results suggest that the direct effluent preparation method for the T47D-KBluc assay is a reasonable approach to estimate the estrogenicity of wastewater effluent. Environ. Toxicol. Chem. 2011;30:439–445. © 2010 SETAC
Role of pocket flexibility in the modulation of estrogen receptor alpha by key residue arginine 394
Authors: Mu Yunsong , Peng Sufen , Zhang Aiqian , Wang Liansheng
Published: October 2010

Estradiol derivatives, with similar structures as estradiol (E2) or estradiol metabolites, have been recognized to have detrimental health effects on wildlife and humans. However, data at the molecular level about interactions of these compounds with biological targets are still lacking. Herein, a flexible docking approach was used to characterize the molecular interaction of nine estradiol derivatives with estrogen receptor alpha (ERα) in the ligand-binding domain. All ligands were docked in the buried hydrophobic cavity of the steroid hormone pocket. In addition, the plasticity of an active site was also identified by reversing amino acid arginine 394 for better ligand-receptor binding affinity. Finally, bioassays based on genetically modified yeast strains were used to validate the quality of molecular simulation because of their rapidity and high sensitivity. The experimental findings about logarithm values of the median effective concentration (EC50) value had a linear correlation with computational binding affinity from molecular docking, which described a pattern of interaction between estradiol derivatives and ER. The estrogenic activity of all compounds, although more or less lower than E2, was proved to possess high severe environmental risks. Considering the sidechain flexibility in the ligand binding pocket, 17α-ethylestradiol-3-cyclopentylether was reported to correlate highly significantly with known induced fit conformational changes based upon proof-of-principle calculations on human ERα with the preservation of a strong salt bridge between glutamic acid 353 and arginine 394. Environ. Toxicol. Chem. 2011;30:330–336. © 2010 SETAC
Development of an enzyme-linked immunosorbent assay for quantifying vitellogenin in Pacific salmon and assessment of field exposure to environmental estrogens
Authors: Peck Karen A , Lomax Daniel P , Olson O. Paul , Sol Sean Y , Swanson Penny , Johnson Lyndal L
Published: October 2010

A competitive enzyme-linked immunosorbent assay was developed to quantitate vitellogenin (VTG) in plasma and serum of coho (Oncorhynchus kisutch) and chinook (O. tshawytscha) salmon. The working range of the assay was 9 to 313 ng/ml (80–20% binding), with 50% binding at 54 ng/ml. The intra-assay and interassay variations at approximately 50% binding were 8.1% (n = 9) and 9.0% (n = 9), respectively. Dilution curves of plasma or serum from coho and chinook females and estrogen-treated males were parallel to the purified coho VTG standard curve. Male plasma samples could be assayed at a minimum dilution of 1:40 (chinook) or 1:75 (coho) without assay interference because of high sample concentration, whereas minimum acceptable dilutions of male serum samples were 1:200 (chinook) or 1:600 (coho). Identification of proper techniques for preserving VTG integrity in plasma and serum samples showed that VTG from both species was robust; both sample types required no protease inhibitor despite subjection to two freeze–thaw cycles. To test its applicability, this assay was used to measure VTG in out-migrating juvenile chinook that were collected from urban and nonurban areas in Puget Sound, Washington, USA. Results showed a small but significant plasma VTG elevation at two urban sites, suggesting that these juveniles may be exposed to environmental estrogens at an early life stage. Also, wild fish tended to have higher plasma VTG levels than hatchery fish collected in the field. Elevation of mean VTG levels was similar to that previously reported in male English sole from the same area, where both males and females exhibited alterations in timing of spawning. Environ. Toxicol. Chem. 2011;30:477–486. © 2010 SETAC
The effect of pH on the uptake and toxicity of the bivalent weak base chloroquine tested onSalix viminalisandDaphnia magna
Authors: Rendal Cecilie , Kusk Kresten Ole , Trapp Stefan
Published: October 2010

The uptake and accumulation of most electrolytes will change with pH because of the different speciation states of these compounds at various pH. Non-ionized compounds will partition into fatty and organic phases (such as cell membranes) more readily than the corresponding charged compounds, and therefore a higher toxicity can be expected. The current study examines the pH-dependent toxicity and bioaccumulation of the bivalent weak base chloroquine (pKa: 10.47 and 6.33, log KOW 4.67) tested on Salix viminalis (basket willow) and Daphnia magna (water flea). The transpiration rates of hydroponically grown willow cuttings were used to determine the toxicity of chloroquine at pH levels of 6, 7, 8, and 9. Root concentration factors were calculated from solution measurements. Results showed more than 10-fold higher toxicity and four to seven times higher root concentration factor at pH 9 than at pH 6. The toxicity of chloroquine was tested on Daphnia magna using the standard Organisation for Economic Co-operation and Development acute toxicity test modified to accommodate testing at pH levels of 7, 8, and 9. Increasing toxicity was seen at higher pH. The results of the current study confirm that the toxicity of weak bases with intermediate pKa values is higher at high pH levels. Environ. Toxicol. Chem. 2011;30:354–359. © 2010 SETAC
Parameter uncertainty in modeling bioaccumulation factors of fish
Authors: Hauck Mara , Hendriks Harrie W.M , Huijbregts Mark A.J , Ragas Ad M.J , van de Meent Dik , Hendriks A. Jan
Published: October 2010

We quantified the uncertainty due to biota-related parameters in estimated bioaccumulation factors (BAFs) of persistent organic pollutants for fish through Monte Carlo simulations. For this purpose, the bioaccumulation model OMEGA (Optimal Modeling for EcotoxicoloGical Applications) was parameterized based on data from the existing literature, analysis of allometric data, and maximum likelihood estimation. Lipid contents, fractions of food assimilated, the allometric rate exponent, normalized food intakes, respiration and growth dilution rates, and partial mass transfer resistances in water and lipid layers were included as uncertain parameters. The uncertainty in partial resistances was particularly important in the estimation of the rate constants for chemical intake from water by fish. Uncertainties in the fractions of food assimilated and partial water layer resistances from and to food were particularly important in the estimation of the rate constants of chemical intake from food. The uncertainty in the model outcomes for the bioaccumulation factors for fish was a factor of 10 (ratio of 95th and fifth percentile estimates), which was mainly caused by the uncertainty in the lipid fraction. For chemicals with a KOW of 103 to 106, the uncertainty in the lipid contents of fish accounted for more than 50% of the uncertainty in the estimated bioaccumulation factor. For chemicals with a high KOW (107 and higher), the fractions of food assimilated and partial resistances also contributed to uncertainty in the estimated bioaccumulation factor (up to 60%). A case study showed that uncertainty in estimated BAF for nonpersistent substances can be dominated by uncertainty in the rate constants for metabolic transformation. Environ. Toxicol. Chem. 2011;30:403–412. © 2010 SETAC
Simultaneous determination of mercury methylation and demethylation capacities of various sulfate-reducing bacteria using species-specific isotopic tracers
Authors: Bridou Romain , Monperrus Mathilde , Gonzalez Pablo Rodriguez , Guyoneaud Rémy , Amouroux David
Published: October 2010

The use of species-specific isotopic tracers for inorganic and methyl mercury has allowed the simultaneous determination of the methylation and demethylation potentials of pure culture of isolated sulfate-reducing (SR) bacterial strains using low Hg species concentration levels (7 µg/L 199Hg(II), 1 µg/L Me201Hg). A major advantage of the method reported here is that it can be used to follow simultaneously both the degradation of the species added but also the formation of their degradation products and thus the determination during the same incubation of the specific methylation/demethylation yields and rate constants. Methylation/demethylation capacities and extents have been found to differ between the tested strains and the tested conditions. The methylating/demethylating capacities of bacteria appear to be strain specific. All the methylating strains were found to demethylate methylmercury (MeHg). The active mechanism responsible for Hg methylation appears directly dependent on the bacterial activity but is not dependent on the metabolism used by the tested bacteria (sulfate reduction, fermentation, or nitrate respiration). The results provide confirmation that SR strains contribute to MeHg demethylation under anoxic conditions, leading to Hg(II) as the end product, consistent with the oxidative degradation pathway. Kinetic experiments have allowed specific transformation rate constants to be addressed for the two reversible processes and the reactivity of each isotopic tracer to be compared. The differential reactivity highlighted the different steps involved in the two apparent processes (i.e., uptake plus internal transformation of mercury species). Methylation appears as the slowest process, mainly controlled by the assimilation of Hg(II), whereas demethylation is faster and not dependent on the MeHg concentration. Environ. Toxicol. Chem. 2011;30:337–344. © 2010 SETAC
Transfer capacity enhancement by adaptive coordinated control of HVDC‐links based on forecasted load paths
Authors: Eriksson Robert , Perninge Magnus , Söder Lennart
Published: October 2010

Due to the intensive use of the transmission networks one of the major issues in electric energy trading is bottlenecks limiting the transfer capacity between different system areas. In this article, a new method for increasing transfer capacity is suggested. The increase in transfer capacity is obtained by an adaptive coordinated modulation control of multiple HVDC‐links in the system. The control method is based on maximizing the distance to the bifurcation surface by adjusting the feedback gain of the HVDC‐links modulation controllers. The system is linearized along the forecasted load path. The feedback gains are then chosen in such a way that system remains stable, in a small signal sense, as long as possible along the forecasted load path. The arising optimization problem is then solved using a particle swarm optimization method. If the load is predicted to increase, instability will eventually occur when the loading reaches a critical limit. Using the proposed control method the point in load‐space where instability occur will be at a significantly higher loading level. The main contribution of this paper is the proposed new method for adaptively coordinating the power modulation of multiple HVDC‐links in a power system, to enhance the total transfer capacity. This in turn will lead to a possibility to increase the traded volumes on the electricity market. Copyright © 2010 John Wiley & Sons, Ltd.
Influence of Steinmetz circuit capacitor degradation on series resonance of networks
Authors: Sainz Luis , Caro M. , Caro E.
Published: October 2010

The Steinmetz circuit is used in AC traction systems to balance consumed currents. In these systems, locating resonances between Steinmetz circuit capacitors and system inductors avoids harmonic problems. In particular, the paper locates analytically the series resonance “observed” from the supply system considering the influence of capacitor degradation with respect to its design value. The study of this resonance is important to avoid problems associated with background voltage distortion. The analytical results are validated with experimental measurements. Copyright © 2010 John Wiley & Sons, Ltd.
A pressure correction method for fluid–particle interaction flow: Direct‐forcing method and sedimentation flow
Authors: Lin San‐Yih , Chin Ya‐Hsien , Hu Jeu‐Jiun , Chen Yi‐Cheng
Published: October 2010

A direct‐forcing pressure correction method is developed to simulate fluid–particle interaction problems. In this paper, the sedimentation flow is investigated. This method uses a pressure correction method to solve incompressible flow fields. A direct‐forcing method is introduced to capture the particle motions. It is found that the direct‐forcing method can also be served as a wall‐boundary condition. By applying Gauss's divergence theorem, the formulas for computing the hydrodynamic force and torque acting on the particle from flows are derived from the volume integral of the particle instead of the particle surface. The order of accuracy of the present method is demonstrated by the errors of velocity, pressure, and wall stress. To demonstrate the efficiency and capability of the present method, sedimentations of many spherical particles in an enclosure are simulated. Copyright © 2010 John Wiley & Sons, Ltd.
Toward accurate simulation and analysis of strong acoustic wave phenomena—A review from the experience of our study on rocket problems
Authors: Fujii Kozo , Nonomura Taku , Tsutsumi Seiji
Published: October 2010

This paper gives an overview of the numerical simulations for the analysis of strong nonlinear acoustic waves during rocket development, with the emphasis on recent ones carried out using large‐scale supercomputers. After the discussion on the difficulties encountered in such simulations, a computational study of blast wave propagation conducted for estimating the safety distance of a rocket is presented. The study was conducted about 20 years ago and the result showed the advantages of the moving grid method as well as the importance of grid resolution studies. A recent study on rocket plume acoustics is then presented. The result shows that the generation and propagation of Mach waves from the plume shear layers are key features to be captured. Direct simulations of such flows have now become feasible owing to the developments in computers and numerical schemes. Then, problems that still remain unsolved are discussed. Our study so far has been limited to simulations using structured grids of high spatial resolution although direct simulations of strongly nonlinear acoustic waves are becoming feasible. More studies have to be carried out for developing highly accurate schemes for unstructured grid systems for the applications to flow configurations over complex geometries. With such improvements, computational fluid dynamics (CFD) would become a still better effective tool for the analysis and estimation of nonlinear acoustic phenomena, especially in aerospace applications. Copyright © 2010 John Wiley & Sons, Ltd.
Stabilized finite element computation of NOx emission in aero‐engine combustors
Authors: Corsini A. , Rispoli F. , Tezduyar T. E.
Published: October 2010

A stabilized finite element formulation for the computation of turbulent reacting flows and NOx emission is presented. The method is based on the Streamline‐Upwind/Petrov–Galerkin (SUPG) and Pressure‐Stabilizing/Petrov‐Galerkin (PSPG) formulations, complemented with directionally formulated diffusion for reaction‐dominated flows (‘DRDJ’ stabilization). The stabilized formulation is applied to the advection–diffusion–reaction equations governing the turbulent combustion and the NOx emission equations based on the thermal and the N2O pathways. The simulation is carried out for a co‐axial burner, with a non‐premixed swirling flame. The burner is operated at high pressure to represent the take‐off conditions for an aero‐engine. The vortical patterns of the swirling flame are analyzed together with the temperature field and flame position. The NOx formation processes are discussed, providing insight into the features of thermal and N2O mechanisms. Copyright © 2010 John Wiley & Sons, Ltd.
A numerical scheme for Euler–Lagrange simulation of bubbly flows in complex systems
Authors: Shams E. , Finn J. , Apte S. V.
Published: October 2010

An Eulerian–Lagrangian approach is developed for the simulation of turbulent bubbly flows in complex systems. The liquid phase is treated as a continuum and the Navier–Stokes equations are solved in an unstructured grid, finite volume framework for turbulent flows. The dynamics of the disperse phase is modeled in a Lagrangian frame and includes models for the motion of each individual bubble, bubble size variations due to the local pressure changes, and interactions among the bubbles and with boundaries. The bubble growth/collapse is modeled by the Rayleigh–Plesset (RP) equation. Three modeling approaches are considered: (a) one‐way coupling, where the influence of the bubble on the fluid flow is neglected, (b) two‐way coupling, where the momentum‐exchange between the fluid and the bubbles is modeled, and (c) volumetric coupling, where the volumetric displacement of the fluid by the bubble motion and the momentum‐exchange are modeled. A novel adaptive time‐stepping scheme based on stability‐analysis of the non‐linear bubble dynamics equations is developed. The numerical approach is verified for various single bubble test cases to show second‐order accuracy. Interactions of multiple bubbles with vortical flows are simulated to study the effectiveness of the volumetric coupling approach in predicting the flow features observed experimentally. Finally, the numerical approach is used to perform a large‐eddy simulation in two configurations: (i) flow over a cavity to predict small‐scale cavitation and inception and (ii) a rising dense bubble plume in a stationary water column. The results show good predictive capability of the numerical algorithm in capturing complex flow features. Copyright © 2010 John Wiley & Sons, Ltd.
3D simulation of wind turbine rotors at full scale. Part II: Fluid–structure interaction modeling with composite blades
Authors: Bazilevs Y. , Hsu M.‐C. , Kiendl J. , Wüchner R. , Bletzinger K.‐U.
Published: October 2010

In this two‐part paper, we present a collection of numerical methods combined into a single framework, which has the potential for a successful application to wind turbine rotor modeling and simulation. In Part 1 of this paper we focus on: 1. The basics of geometry modeling and analysis‐suitable geometry construction for wind turbine rotors; 2. The fluid mechanics formulation and its suitability and accuracy for rotating turbulent flows; 3. The coupling of air flow and a rotating rigid body. In Part 2, we focus on the structural discretization for wind turbine blades and the details of the fluid–structure interaction computational procedures. The methods developed are applied to the simulation of the NREL 5MW offshore baseline wind turbine rotor. The simulations are performed at realistic wind velocity and rotor speed conditions and at full spatial scale. Validation against published data is presented and possibilities of the newly developed computational framework are illustrated on several examples. Copyright © 2010 John Wiley & Sons, Ltd.
Stability and convergence of a Galerkin‐characteristics finite element scheme of lumped mass type
Authors: Pironneau O. , Tabata M.
Published: October 2010

A Galerkin‐characteristics finite element scheme of lumped mass type is presented for the convection–diffusion problems. Under the weakly acute triangulation hypothesis the scheme is proved to be stable and convergent in the L∞‐norm. Using the Freefem, we show 2D and 3D numerical examples, which reflect the robustness of the scheme and the theoretical convergence result. Copyright © 2010 John Wiley & Sons, Ltd.
Conjugate gradients on multiple GPUs
Authors: Georgescu Serban , Okuda Hiroshi
Published: October 2010

A GPU‐accelerated Conjugate Gradient solver is tested on eight different matrices with different structural and numerical characteristics. The first four matrices are obtained by discretizing the 3D Poisson's equation, which arises in many fields such as computational fluid dynamics, heat transfer and so on. Their relatively low bandwidth and low condition numbers makes them ideal targets for GPU acceleration. We chose another four matrices from the other end of the spectrum, both ill‐conditioned and with very large bandwidth. This paper concentrates on the computational aspects related to running the solver on multiple GPUs. We develop a fast distributed sparse‐matrix vector multiplication routine using optimized data formats that allows the overlapping of communication with computation and, at the same time, the sharing of some of the work with the CPU. By a thorough analysis of the time spent in communication and computation, we show that the proposed overlapped implementation outperforms the non‐overlapped one by a large margin and provides almost perfect strong scalability for large Poisson‐type matrices. We then benchmark the performance of the entire solver, using both double precision and single precision combined with iterative refinement and report up to 22× acceleration when using three GPUs as compared with one of the most powerful Intel Nehalem CPUs available today. Finally, we show that using GPUs as accelerators not only brings an order of magnitude speedup but also up to 5x increase in power efficiency and over 10x increase in cost effectiveness. Copyright © 2010 John Wiley & Sons, Ltd.
Genotype‐based association mapping of complex diseases: gene‐environment interactions with multiple genetic markers and measurement error in environmental exposures
Authors: Lobach Iryna , Fan Ruzong , Carroll Raymond J.
Published: October 2010

With the advent of dense single nucleotide polymorphism genotyping, population‐based association studies have become the major tools for identifying human disease genes and for fine gene mapping of complex traits. We develop a genotype‐based approach for association analysis of case‐control studies of gene‐environment interactions in the case when environmental factors are measured with error and genotype data are available on multiple genetic markers. To directly use the observed genotype data, we propose two genotype‐based models: genotype effect and additive effect models. Our approach offers several advantages. First, the proposed risk functions can directly incorporate the observed genotype data while modeling the linkage disequilibrium information in the regression coefficients, thus eliminating the need to infer haplotype phase. Compared with the haplotype‐based approach, an estimating procedure based on the proposed methods can be much simpler and significantly faster. In addition, there is no potential risk due to haplotype phase estimation. Further, by fitting the proposed models, it is possible to analyze the risk alleles/variants of complex diseases, including their dominant or additive effects. To model measurement error, we adopt the pseudo‐likelihood method by Lobach et al. [2008]. Performance of the proposed method is examined using simulation experiments. An application of our method is illustrated using a population‐based case‐control study of association between calcium intake with the risk of colorectal adenoma development. Genet. Epidemiol. 34:792‐802, 2010. © 2010 Wiley‐Liss, Inc.
Development and validation of an instrument to detect depression in nursing homes. Nursing homes short depression inventory (NH‐SDI)
Authors: Prado‐Jean Annie , Couratier Philippe , Bénissan‐Tevi Laurent Amounou , Nubukpo Philippe , Druet‐Cabanac Michel , Clément Jean Pierre
Published: October 2010

Depression is often overlooked in elderly nursing home residents because symptoms may be masked or dismissed as an inevitable consequence of ageing. Current tools for the detection of depression in institutionalised older people are not always specific.

Aims

To construct and verify an instrument with which to detect depression in elderly nursing home residents (NH‐SDI).

Method

Firstly for the construction, 328 elderly people were selected at random from the residents of 17 nursing homes in France, and examined by a single investigator. The examination included a psychiatric assessment, an evaluation of cognitive function using the MMSE, an evaluation of depressive state using four different instruments (mini‐GDS, Goldberg, DMAS, CSDD), and assessment of any changes in behaviour in those suffering from dementia, using the NPI. A second stage was to confirm NH‐SDI in 99 institutionalised subjects.

Results

Following the selection of items, we created a scale of 16 dichotomous items (NH‐SDI). The internal consistency was satisfactory (α Cronbach = 0.85), as was its reliability with a sensitivity of 85.1% and a specificity of 86.5% for a cut‐off score above 5.

Conclusions

The NH‐SDI appears to be a useful instrument for the detection of depression in nursing homes and can easily be applied by healthcare staff as part of routine procedures. Copyright © 2010 John Wiley & Sons, Ltd.
Demonstration of safety in Alzheimer's patients for intervention with an anti‐hypertensive drug Nilvadipine: results from a 6‐week open label study
Authors: Kennelly S. P. , Abdullah L. , Paris D. , Parish J. , Mathura V. , Mullan M. , Crawford F. , Lawlor B. A. , Kenny R. A.
Published: October 2010

Background

Nilvadipine may lower rates of conversion from mild‐cognitive impairment to Alzheimer's disease (AD), in hypertensive patients. However, it remains to be determined whether treatment with nilvadipine is safe in AD patients, given the higher incidence of orthostatic hypotension (OH) in this population, who may be more likely to suffer from symptoms associated with the further exaggeration of a drop in BP.

Objective

The aim of this study was to investigate the safety and tolerability of nilvadipine in AD patients.

Methods

AD patients in the intervention group (n = 56) received nilvadipine 8 mg daily over 6‐weeks, compared to the control group (n = 30) who received no intervention. Differences in systolic (SBP) and diastolic (DBP) blood pressure, before and after intervention, was assessed using automated sphygmomanometer readings and ambulatory BP monitors (ABP), and change in OH using a finometer. Reporting of adverse events was monitored throughout the study.

Results

There was a significant reduction in the SBP of treated patients compared to non‐treated patients but no significant change in DBP. Individuals with higher initial blood pressure (BP) had greater reduction in BP but individuals with normal BP did not experience much change in their BP. While OH was present in 84% of the patients, there was no further drop in BP recorded on active stand studies. There were no significant differences in adverse event reporting between groups.

Conclusion

Nilvadipine was well tolerated by patients with AD. This study supports further investigation of its efficacy as a potential treatment for AD. Copyright © 2010 John Wiley & Sons, Ltd.
Depression in mild dementia: associations with diagnosis, APOE genotype and clinical features
Authors: Fritze Friederike , Ehrt Uwe , Sønnesyn Hogne , Kurz Martin , Hortobágyi Tibor , Nore Sabine Piepenstock , Ballard Clive , Aarsland Dag
Published: October 2010

Background

Depression is common in dementia, with important clinical implications. Few studies of depression in dementia with Lewy bodies are available, and the results are inconsistent.

Objective

To examine the frequency of depression and its characteristics and correlates, in people with mild dementia.

Methods

All referrals for patients with a first time diagnosis of dementia to geriatric and older psychiatry outpatient clinics in the counties of Rogaland and Hordaland in Western Norway from March 2005 to March 2007 were screened for the study. Participants and their caregivers underwent a comprehensive and standardised diagnostic and assessment procedure. The depression subitem of the neuropsychiatric inventory (NPId) and Montgomery and Åsberg depression rating scale (MADRS) were used to estimate depression. Cut‐off scores for any depression were 0/1 (NPId) and 6/7 (MADRS), and for clinically significant depression 3/4 and 14/15, respectively.

Results

Two hundered and twenty‐three subjects with dementia participated, of whom 59 and 50% showed symptoms of depression assessed by NPI or MADRS, respectively, and 25 and 16% had clinically significant depression as measured by NPI and MADRS, respectively. Depression was more frequent in dementia with Lewy bodies (DLB) than in Alzheimer's disease (AD; p < 0.05). APOE genotype was available in 153 patients, and in AD, but not in DLB, a general linear model showed that the presence of APOEε4 allele was significantly associated with depression (F = 4.14; p = 0.045).

Conclusion

Depression is common even in mild dementia, and more common and severe in DLB compared to AD. Future studies should explore the longitudinal course of depression in DLB, and the neural underpinnings of depression in DLB. Copyright © 2010 John Wiley & Sons, Ltd.
The APOE polymorphism in Alzheimer's disease patients with neuropsychiatric symptoms and syndromes
Authors: D'Onofrio Grazia , Panza Francesco , Seripa Davide , Sancarlo Daniele , Paris Francesco , Cascavilla Leandro , Urbano Maria , Gravina Carolina , Fontana Andrea , Solfrizzi Vincenzo , Pellegrini Fabio , Pilotto Alberto
Published: October 2010

Background

Neuropsychiatric symptoms (NPS) are a common feature of Alzheimer's disease (AD), resulting in particular AD endophenotypes. The common AD genetic risk factor apolipoprotein E (APOE) has been suggested underlying these AD endophenotypes.

Methods

APOE genotyping, a comprehensive geriatric assessment (CGA), and Neuropsychiatric Inventory were performed on 322 consecutive older patients. Patients were divided into three groups: AD with NPS (N = 93), AD without NPS (N = 108), and, as a control group, patients with no cognitive impairment (NoCI: N = 121). Patients with NPS were further sub‐divided in four groups according to the European Alzheimer's Disease Consortium (EADC) classification of neuropsychiatric syndromes in AD: hyperactive, psychotic, affective, and apathetic.

Results

AD patients with NPS showed a significantly higher grade of cognitive impairment, more severity stage of dementia, more disability in the activities of daily living (ADL), and the instrumental ADL than AD patients without NPS. As expected, an higher frequency of APOE ε3/ε4 genotype was observed in patients with AD, both with and without NPS, than patients with NoCI. No difference in the distribution of APOE genotypes was found between AD patients with vs. without NPS. However, in AD patients APOE ε4‐carriers, there was an increased risk of affective [odds ratio (OR): 2.34, 95% confidence interval (CI): 1.19–4.58) and apathetic (OR: 2.24,95%CI: 1.19–4.22) syndromes.

Conclusions

These findings did not suggest a significant association between APOE polymorphism and presence of NPS in AD patients. In AD patients with NPS, however, APOE ε4‐carrier status was associated with an increased risk of affective and apathetic syndromes. Copyright © 2010 John Wiley & Sons, Ltd.
Nonalcoholic Fatty Liver Disease: is It All in the Genes?
Authors: Torres Dawn McDowell , Harrison Stephen A.
Published: October 2010

Abstract

Background: Nonalcoholic fatty liver disease is associated with hepatic insulin resistance and type 2 diabetes mellitus. Whether this association has a genetic basis is unknown. Methods: In 95 healthy Asian Indian men, a group known to have a high prevalence of nonalcoholic fatty liver disease, we genotyped two single-nucleotide polymorphisms (SNPs) in the gene encoding apolipoprotein C3 (

APOC3

) that are known to be associated with hypertriglyceridemia (rs2854116 [T-455C] and rs2854 117 [C-482T]). Plasma apolipoprotein C3 concentrations, insulin sensitivity, and hepatic triglyceride content were measured. We also measured plasma triglyceride concentrations and retinyl fatty acid ester absorption as well as plasma triglyceride clearance after oral and intravenous fat-tolerance tests. Liver triglyceride content and

APOC3

genotypes were also assessed in a group of 163 healthy non-Asian Indian men. Results: Carriers of the

APOC3

variant alleles (C-482T, T-455C, or both) had a 30% increase in the fasting plasma apolipoprotein C3 concentration, as compared with the wild-type homozygotes. They also had a 60% increase in the fasting plasma triglyceride concentration, an increase by a factor of approximately two in the plasma triglyceride and retinyl fatty acid ester concentrations after an oral fat-tolerance test, and a 46% reduction in plasma triglyceride clearance. The prevalence of nonalcoholic fatty liver disease was 38% among variant-allele carriers and 0% among wild-type homozygotes (P<0.001). The subjects with nonalcoholic fatty liver disease had marked insulin resistance. A validation study involving non-Asian Indian men confirmed the association between

APOC3

variant alleles and nonalcoholic fatty liver disease.

Conclusions:

The polymorphisms C-482T and T-455C in

APOC3

are associated with nonalcoholic fatty liver disease and insulin resistance.
Functional and structural aspects of helicobacter pylori acidic stress response factors
Authors: Zanotti Giuseppe , Cendron Laura
Published: October 2010

Schematic Representation of the Factors Involved in the Urease‐Dependent Mechanism of Resistance of H. pylori to Acid Stress by Giuseppe Zanotti and Laura Cendron, pp. 715–723.