bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of vibrational relaxation and molecular reorientation in liquids: a Raman spectroscopic study
Authors: Gomti Devi Th.
Published: January 2010

The vibrational relaxation and molecular reorientational processes in liquids have been studied in some carbonyl‐containing molecules using the acetonitrile (ACN) solvent. The vibrational and reorientational processes have been studied in correspondence with correlation times. The screening effect due to dielectric has been studied and the Onsager reaction field model has been tested. The study shows that repulsive types of intermolecular forces play an important role in complex systems. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis and Electrochemistry of Schiff Base Cobalt(III) Complexes and Their Catalytic Activity for Copolymerization of Epoxide and Carbon Dioxide
Authors: Zhuang Xiuli , Oyaizu Kenichi , Niu Yongsheng , Koshika Kenichiroh , Chen Xuesi , Nishide Hiroyuki
Published: January 2010

A series of cobalt complexes with N,N,O,O‐tetradentate Schiff base ligands were prepared. All the complexes were characterized by spectroscopy and electrochemical methods. An X‐ray crystal structure analysis revealed that L1‐CoIII‐dnp was monomeric with a six‐coordinated central cobalt(III) atom in the solid state. The complexes were employed as catalysts for the alternating copolymerization of CO2 and racemic propylene oxide. End group analysis of the resulting polymer provided strong evidence for a monomer insertion mechanism for the propagation step. The catalytic activity was interpreted using the redox potential of cobalt(II/III) for the L‐CoIII‐dnp complexes, which offered a measure of the bond strength, or the degree of inertness of the axial ligand, to promote or suppress the monomer insertion.

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Poly(lactic acid)/Aluminum Oxide Composites Fabricated by Sol‐Gel and Melt Compounding Processes
Authors: Yuzay Isinay E. , Auras Rafael , Selke Susan
Published: January 2010

Aluminum‐oxide‐coated PLA pellets, particles derived from aluminum oxide sol‐gel, and calcinated α‐Al2O3 powders were used to fabricate PLA/AlOx composites. The formation of aluminum oxide was confirmed by FTIR and EDS. SEM images suggested the melt compounding system provided a fairly homogeneous dispersion of AlOx particles in the PLA matrix. XRD analysis showed PLA and PLA/AlOx composites were both amorphous. The incorporation of AlOx particles did not alter the melting temperature of PLA. However, the shape and intensity of the melting endotherms was significantly changed, suggesting bimodal melting behavior. UV‐Vis transmission spectra suggested that PLA/AlOx composites may act as a better UV barrier than neat PLA.

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Impact of Nanoscale Confinement on Crystal Orientation of Poly(ethylene oxide)
Authors: Wang Haopeng , Keum Jong K. , Hiltner Anne , Baer Eric
Published: January 2010

Using a layer‐multiplying coextrusion process to fabricate films with thousands of alternating polymer nanolayers, we report here a new crystalline morphology in confined polymer nanolayers and an abrupt transition in the crystallization habit. At higher temperatures, poly(ethylene oxide) crystallizes as large, in‐plane lamellae. A 5 °C change in the crystallization temperature produces an on‐edge lamellar orientation. The results point to a transition from heterogeneous nucleation to substrate‐assisted nucleation. This may be a general phenomenon that accounts for previously unexplained differences in the preferred chain alignment of confined polymer crystals.

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Poly(2‐oxazoline)s as Smart Bioinspired Polymers
Authors: Schlaad Helmut , Diehl Christina , Gress Anja , Meyer Matthias , Demirel A. Levent , Nur Yusuf , Bertin Annabelle
Published: January 2010

Poly(2‐alkyl‐2‐oxazoline)s can be regarded as pseudo‐peptides or bioinspired polymers, which are available through living/controlled cationic polymerization and polymer (“click”) modification procedures. Materials and solution properties may be adjusted via the nature of the side chain (hydrophilic‐hydrophobic, chiral, bio‐functional, etc.), opening the way to stimulus‐responsive materials and complex colloidal structures in aqueous environments. Herein, we give an overview over the macromolecular engineering of polyoxazolines, including the synthesis of biohybrids, and the “smart”/bioinspired aggregation behavior in solution.

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Holes and Ledges Created by Multilayer Assembly on Polyelectrolyte Brushes: A Novel Route for the Three‐Dimensional Nanoscale Design of Surfaces
Authors: Llarena Irantzu , Ramos Jagoba J. Iturri , Donath Edwin , Moya Sergio E.
Published: January 2010

The layer‐by‐layer (LBL) assembly of poly(diallyldimethylammonium chloride) and poly(sodium styrene sulfonate) on poly(sulfo propyl methacrylate) brushes resulted in films with nanometer‐ and micrometer‐sized holes and ledges, observed by atomic force microscopy and scanning electron microscopy. Polyelectrolyte assembly was followed by the quartz microbalance technique. The formation of ledges and holes is explained by the interaction of the brush polymers with the incoming polyelectrolytes during the LBL assembly, inducing a spatially localized and self‐organized accumulation of the assembled polymers.

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Crystallization‐Induced Phase Segregation Based on Double‐Crystalline Blends of Poly(3‐hexylthiophene) and Poly(ethylene glycol)s
Authors: Zhao Kui , Ding Zicheng , Xue Longjian , Han Yanchun
Published: January 2010

Crystallization‐induced vertical stratified structures were constructed based on double‐crystalline poly(3‐hexylthiophene) (P3HT)/poly(ethylene glycol)s (PEG) systems at room temperature, in which the P3HT crystallinity and the mechanism were investigated. Vertical stratified microstructures with highly crystalline P3HT network on the surface were formed when depositing from marginal solvents, while lateral phase‐separated structures or low P3HT crystallinity were observed for good solvents. The morphological differences came from the solvent effect. In marginal solvents, p‐xylene and dichloromethane, P3HT large‐scale microcrystallites were generated in solution, which ensured the priority of P3HT crystalline sequence, and phase separation began in the liquid states. When the PEG matrix began to crystallize, great energy from which the second phase separation was induced drove P3HT crystallites to the surface, resulting in the formation of vertical stratified microstructures with highly crystalline P3HT network on the surface. The method, crystallization‐induced phase segregation of crystalline–crystalline blends in marginal solvent, provides a facile way to construct vertically stratified structures, in which P3HT highly crystalline network is favored.

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Toward Tailor‐Made Biocide Materials Based on Poly(propylene)/Copper Nanoparticles
Authors: Palza Humberto , Gutiérrez Sebastian , Delgado Katherine , Salazar Oriana , Fuenzalida Victor , Avila Jonathan I. , Figueroa Guillermo , Quijada Raúl
Published: January 2010

A set of poly(propylene) composites containing different amounts of copper nanoparticles (CNP) were prepared by the melt mixed method and their antimicrobial behavior was quantitatively studied. The time needed to reduce the bacteria to 50% dropped to half with only 1 v/v % of CNP, compared to the polymer without CNP. After 4 h, this composite killed more than 99.9% of the bacteria. The biocide kinetics can be controlled by the nanofiller content; composites with CNP concentrations higher than 10 v/v % eliminated 99% of the bacteria in less than 2 h. X‐ray photoelectron spectroscopy did not detect CNP at the surface, therefore the biocide behavior was attributed to copper in the bulk of the composite.

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Initiation Kinetics in Free‐Radical Polymerization: Prediction of Thermodynamic and Kinetic Parameters Based on ab initio Calculations
Authors: Dossi Marco , Storti Giuseppe , Moscatelli Davide
Published: January 2010

Initiation kinetics in free radical polymerization is investigated using density functional theory. Thermodynamic and kinetic parameters of the initiation reactions are predicted, and the role of the initiators in the polymerization process is evaluated. Methyl acrylate, methyl methacrylate, acrylonitrile, and styrene homo‐polymerizations with different initiators are studied. Reaction enthalpy and activation energy for each reaction between monomer and the radical fragments arising from the initiators have been determined. The initiation kinetic constants for all of these initiation reactions are evaluated and compared with both computational and experimental propagation kinetic constants of each monomer.

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Development of Entanglements in a Fully Disentangled Polymer Melt
Authors: Vettorel Thomas , Kremer Kurt
Published: January 2010

A long‐lived metastable “new melt” state of polymers has been recently reported, where monomers exhibit different mobilities due to an unusual distribution of entanglements. We study the relaxation of (fully disentangled) globules to the entangled state by means of computer simulations, and compare our data to the scenario of de Gennes' explosion upon melting. The entanglement length Ne is measured using the primitive path analysis method. The results show that in the case of relatively short chains (N ≈ 20Ne), the relaxation of the entanglement length is very fast compared to that of the chains' size which slows down as the chain length N exceeds the equilibrium value of Ne.

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Has ‘lifetime prevalence’ reached the end of its life? An examination of the concept
Authors: Streiner David L. , Patten Scott B. , Anthony James C. , Cairney John
Published: January 2010

Many cross‐sectional surveys in psychiatric epidemiology report estimates of lifetime prevalence, and the results consistently show a declining trend with age for such disorders as depression and anxiety. In a closed cohort with no mortality, lifetime prevalence should increase or remain constant with age. For mortality to account for declining lifetime prevalence, mortality rates in those with a disorder must exceed those without a disorder by a sufficient extent that more cases would be removed from the prevalence pool than are added by new cases, and this is unlikely to occur across most of the age range. We argue that the decline in lifetime prevalence with age cannot be explained by period or cohort effects or be due to a survivor effect, and are likely due to a variety of other factors, such as study design, forgetting, or reframing. Further, because lifetime prevalence is insensitive to changes in treatment effectiveness or demand for services, it is a parameter that should be dropped from the lexicon of psychiatric epidemiology. Copyright © 2009 John Wiley & Sons, Ltd.
Bilateral internal carotid artery occlusions in a pediatric patient with refractory acute myeloid leukemia
Authors: Fuh Beng , Lurito Joseph , Grossi Mauro , Daeschner Charles , Russo Suzanne
Published: January 2010

Thromboembolism is a well‐known complication of cancer including acute myeloid leukemia (AML) especially in patients with high myeloblast counts. However, spontaneous vaso‐occlusion in the main arteries is very rare especially in patients with low blast counts and no pre existing vasculopathy. We report the case of a 3‐year‐old male with refractory AML who developed spontaneous bilateral internal carotid artery occlusion with diffuse cerebral infarcts. Strokes are rarely secondary to spontaneous carotid artery thrombosis and few cases have been reported in the literature. Pediatr Blood Cancer 2010;54:770–772. © 2010 Wiley‐Liss, Inc.
Structures of human Bruton's tyrosine kinase in active and inactive conformations suggest a mechanism of activation for TEC family kinases
Authors: Marcotte Douglas J. , Liu Yu‐Ting , Arduini Robert M. , Hession Catherine A. , Miatkowski Konrad , Wildes Craig P. , Cullen Patrick F. , Hong Victor , Hopkins Brian T. , Mertsching Elisabeth , Jenkins Tracy J. , Romanowski Michael J. , Baker Darren P. , Silvian Laura F.
Published: January 2010

Bruton's tyrosine kinase (BTK), a member of the TEC family of kinases, plays a crucial role in B‐cell maturation and mast cell activation. Although the structures of the unphosphorylated mouse BTK kinase domain and the unphosphorylated and phosphorylated kinase domains of human ITK are known, understanding the kinase selectivity profiles of BTK inhibitors has been hampered by the lack of availability of a high resolution, ligand‐bound BTK structure. Here, we report the crystal structures of the human BTK kinase domain bound to either Dasatinib (BMS‐354825) at 1.9 Å resolution or to 4‐amino‐5‐(4‐phenoxyphenyl)‐7H‐pyrrolospyrimidin‐ 7‐yl‐cyclopentane at 1.6 Å resolution. This data provides information relevant to the development of small molecule inhibitors targeting BTK and the TEC family of nonreceptor tyrosine kinases. Analysis of the structural differences between the TEC and Src families of kinases near the Trp‐Glu‐Ile motif in the N‐terminal region of the kinase domain suggests a mechanism of regulation of the TEC family members.
Genetic encoding of non‐natural amino acids in Drosophila melanogaster Schneider 2 cells
Authors: Mukai Takahito , Wakiyama Motoaki , Sakamoto Kensaku , Yokoyama Shigeyuki
Published: January 2010

Insect cells are useful for the high‐yield production of recombinant proteins including chemokines and membrane proteins. In this study, we developed an insect cell‐based system for incorporating non‐natural amino acids into proteins at specific sites. Three types of promoter systems were constructed, and their efficiencies were compared for the expression of the prokaryotic amber suppressor tRNATyr in Drosophila melanogaster Schneider 2 cells. When paired with a variant of Escherichia coli tyrosyl‐tRNA synthetase specific for 3‐iodo‐L‐tyrosine, the suppressor tRNA transcribed from the U6 promoter most efficiently incorporated the amino acid into proteins in the cells. The transient and stable introductions of these prokaryotic molecules into the insect cells were then compared in terms of the yield of proteins containing non‐natural amino acids, and the “transient” method generated a sevenfold higher yield. By this method, 4‐azido‐L‐phenylalanine was incorporated into human interleukin‐8 at a specific site. The yield of the azido‐containing IL‐8 was 1 μg/1 mL cell culture, and the recombinant protein was successfully labeled with a fluorescent probe by the Staudinger–Bertozzi reaction.
Electronic and optical properties of group IV two‐dimensional materials
Authors: Pulci O. , Gori P. , Marsili M. , Garbuio V. , Seitsonen A. P. , Bechstedt F. , Cricenti A. , Del Sole R.
Published: January 2010

The microscopic study of complex systems has reached a high level of accuracy that allows for a deep understanding of their structure, electronic properties, and optical spectra. The theoretical investigation of surfaces is nowadays routinely done within density functional theory, for ground state properties, and, with a larger computational load, within many‐body perturbation theory, for excited states properties. In this paper we present and discuss examples of calculations for group IV two‐dimensional systems such as a clean silicon surface, a tin–germanium interface, graphene, and graphane, pointing out the importance of a pertinent treatment of many‐body effects.
New insight into the photochromic mechanism of 1,3‐diphenyl‐4‐(4‐fluoro)benzal‐5‐pyrazolone N(4)‐phenyl semicarbazone
Authors: Yang Yinling , Wu Dongling , Jia Dianzeng , Liu Lang , Liu Anjie
Published: January 2010

Density functional theory (DFT) calculation has been carried out to investigate the photochromic mechanism of 1, 3‐diphenyl‐4‐(4‐fluoro)benzal‐5‐pyrazolone N(4)‐phenyl semicarbazone. The novel mechanism, proposed by us, has different reaction pathway between the forward and the reverse process. The energy barrier of the forward direction was calculated to be significantly larger than that of the reverse direction (30.35 kcal/mol to 9.88 kcal/mol), which confirms the experimental observation that the forward process needs irradiation of light while the reverse one will take place easily when heated. The solvent effect on the relative stabilities of those isomers that may involve in the reaction has also been investigated by applying the polarizable continuum model (PCM) of the self‐consistent reaction field theory. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Convergence and computational efficiency enhancements in the iterative solution of the G‐particle‐hole hypervirial equation
Authors: Alcoba D. R. , Tel L. M. , Pérez‐Romero E. , Valdemoro C.
Published: January 2010

The G‐particle‐hole hypervirial (GHV) equation has been recently reported (Valdemoro et al., Sixth International Congress of the International Society for Theoretical Chemical Physics Vancouver: Canada, 2008. Alcoba et al., Int J Quantum Chem 2009, 109, 3178; Valdemoro et al., Int J Quantum Chem 2009, 109, 2622). This equation is the newest member of the family of equations which can be obtained by applying a matrix‐contracting mapping (Valdemoro, An R Soc Esp Fís 1983, 79, 106; Valdemoro, Phys Rev A 1985, 31, 2114; Valdemoro, in Density Matrices and Density Functionals, Reidel: Dordrecht, 1987; p 275.) to the matrix representation in the N‐electron space of the Schrödinger, Liouville and hypervirial equations. The procedure that we have applied in order to solve the GHV equation exploits the stationary property of the hypervirials (Hirschfelder, J Chem Phys 1960, 33, 1462; Hirschfelder and Epstein, Phys Rev 1961, 123, 1495) and follows the general lines of Mazziotti's variational approach for solving the anti‐Hermitian contracted Schrödinger equation (ACSE) (Mazziotti, Phys Rev Lett 2006, 97, 143002; Mazziotti, Phys Rev A 2007, 75, 022505; Mazziotti, J Chem Phys 2007, 126, 184101). In this article, we report how the method's convergence has been significantly enhanced and how its computational scaling has been considerably reduced (in both floating‐point operations and storage). The results for a variety of atomic and molecular calculations confirming these methodological improvements are reported here. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Influence of substitution on the strength and nature of CH···N hydrogen bond in XCCH···NH3complexes
Authors: Roohi Hossein , Bagheri Sotoodeh
Published: January 2010

The effect of substitution on the strength and nature of CH···N hydrogen bond in XCCH···NH3(X = F, Cl, Br, OH, H, Me) and NCH···NH3complexes were investigated by quantum chemical calculations. Ab initio calculations were performed using MP2 method with a wide range of basis sets. With tacking into account the BSSE and ZPVE, the values of BEs decrease. Replacement of the nonparticipatory hydrogen atom of HCCH by the electronegative atoms (F, Cl, and Br), lead to the BEs increases. The BE corresponding to the replacement of the nonparticipatory hydrogen atom of HCCH by the OH and CH3groups decreases. A far greater enhancement of the interaction energy arises from replacement of HCCH by the more acidic HCN. The natural bond orbital analysis and the Bader's quantum theory of atoms in molecules were also used to elucidate the interaction characteristics of these complexes. The electrostatic nature of H‐bond interactions is predicted from QTAIM analysis. In addition, the relationship between the isotropic and anisotropic chemical shifts of the bridging hydrogen and binding energy of complexes as well as electron density at N···H BCPs were investigated. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Effect of magnetic field on diamagnetic susceptibility of two interacting electrons in a quantum dot
Authors: Radhakrishnan N. , Peter A. John
Published: January 2010

We have estimated the energy levels of the low‐lying states as a function of magnetic field when two electrons are introduced in a quantum dot (QD). Oscillator strength of interacting electrons for different magnetic field strengths has been calculated. There is no appreciable change in oscillator strength for stronger confinements for all the magnetic field strengths. We present the shift of diamagnetic susceptibility of a hydrogenic donor impurity in GaAs/Ga1−xAlxAs QD systems for the ground and low lying excited states. The effect of magnetic field on diamagnetic susceptibilities is estimated by two different methods and it has been found that values obtained from both the methods resemble each other. The diamagnetic shift is in good agreement with the other investigators. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Approximate solutions of the Schrödinger equation with the generalized Morse potential model including the centrifugal term
Authors: Zhang Lie‐Hui , Li Xiao‐Ping , Jia Chun‐Sheng
Published: January 2010

By using a new improved approximation scheme to deal with the centrifugal term, we solve approximately the Schrödinger equation with the generalized Morse potentials for the arbitrary angular momentum values. The bound state energy spectra and the unnormalized radial wave functions have been approximately obtained by using the basic concept of the supersymmetric shape invariance formalism and the function analysis method. The numerical experiments show that our approximate results are in better agreement with those obtained by using the numerical integration approach than the approximate results obtained by using the conventional approximation scheme to deal with the centrifugal term. We also calculate the rotational transition frequencies for HF molecule and compare them with the experimental data. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical study of the reactions of lanthanide ions (Ce+, Pr+) with CO2 in the gas phase
Authors: Wang Yong‐Cheng , Liu Hui‐Wen , Geng Zhi‐Yuan , Lv Ling‐Ling , Si Yu‐Bing , Wang Qing‐Yun , Wang Qiang , Cui Dan‐Dan
Published: January 2010

The mechanisms of the reaction of lanthanide ions (Ce+ and Pr+) with the carbon dioxide were investigated at the B3LYP level of theory. The crossing points (CPs) between the different potential energy surfaces (PESs) have been located by means of the intrinsic reaction coordinate approach used by Yoshizawa et al., and corresponding minimum energy crossing points (MECPs) that we obtained by the mathematical algorithm proposed by Harvey et al. has also been used. In addition, possible spin inversion processes are discussed by means of spin‐orbit coupling (SOC) calculations. The value of 61.68 cm−1 (for MECP1) and 69.17 cm−1 (for MECP2) for the SOC constants indicates that the spin crossing process in Ln+ + CO2 (1∑) reaction can be occurred efficiently because of the large SOC involved. And the O‐atom affinities (OA) testified that the argumentation is thermodynamically allowed. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Uranyl complexation by monodentate nitrogen donor ligands. A relativistic density functional study
Authors: Zakharieva Olga , Kremleva Alena , Krüger Sven , Rösch Notker
Published: January 2010

To examine the interaction of uranyl with nitrogen containing groups of humic substances, the model complexes [UO2(H2O)4LN]2+, LN = NH2CH3, N(CH3)3, and NC5H5 in aqueous solution were studied computationally with an all‐electron relativistic density functional method. Results are compared with the corresponding penta‐aqua complex of uranyl. Although pyridine coordinates with about the same strength as L = H2O, methylamine binds ∼10 kJ mol−1 stronger and trimethylamine ∼40 kJ mol−1 weaker than a fifth aqua ligand. Yet, each of these ligands LN donates about the same amount of charge to uranyl as L = H2O. UN bonds are ∼10 pm longer than the UO bonds of the aqua ligands. From the present model results, one does not expect that, when compared with carboxyl groups, monodentate N‐containing functional groups contribute significantly to uranyl complexation by humic substances. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
TPM‐based protection for mobile agents
Authors: Muñoz Antonio , Maña Antonio
Published: January 2010

Mobile agent is a promising paradigm for emerging ubiquitous computing and ambient intelligent scenarios. We believe that security is the most important issue for the widespread deployment of applications based on mobile agent technology. Indeed, community agrees that without the proper security mechanisms, use of mobile agent‐based applications will be impossible. From our perspective, the security problem in mobile agents is the gathering of two subproblems; the problem of the agent protection and the problem of the host protection. This paper presents a hardware‐based mechanism focused on solving the protection of the agent problem, which is a well known problem named the ‘malicious host’. The solution presented in this paper bases its security in the trust and the security functionalities provided by the trusted platform module (TPM). Thus, migration process of mobile agents is protected when it actually takes place. A complete description of the secure migration can be found in the secure migration protocol section of this paper. Moreover, a validation of this protocol was performed by means of the AVISPA tool suite. Additionally, a first study about the use of an alternative protocol as the direct anonymous attestation protocol was done. Finally, the result of this work is the Secure Migration Library for agents (SecMiLiA), which is completely described in following sections. Copyright © 2010 John Wiley & Sons, Ltd.
Protective effects of eicosapentaenoic acid on genotoxicity and oxidative stress of cyclophosphamide in mice
Authors: Li Mei , Zhu Qin , Hu Changwei , Giesy John P. , Kong Zhiming , Cui Yibin
Published: January 2010

The aim of this article is to elucidate the mechanism by which eicosapentaenoic acid (EPA) acts against cyclophosphamide (CP)‐induced effects. The prevalence of micronuclei, the extent of lipid peroxidation, and the status of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) in both liver and serum of mice were used as intermediate biomarkers of chemoprotection. Lipid peroxidation and associated compromised antioxidant defenses (CAT and GPX) in CP treated mice were observed in the liver, serum, and were accompanied by increased prevalence of micronuclei in bone marrow. The number of MN was significantly different (p < 0.01) between the groups treated with CP (group III, IV, V, VI) and the solvent control (group II) (3.2 ± 0.7‰). There was a dose‐dependent reduction in formation CP induced micronuclei by treatment with 100, 200, or 300 mg EPA/kg BW mice. Activities of SOD, CAT, and extent of lipid peroxidation were statistically different in liver cells of mice exposed to EPA only with CP compared with the CP group (group III). The present findings imply that EPA may be a potential antigenotoxic, antioxidant and chemopreventive agent and could be used as an adjuvant in chemotherapeutic applications. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2011.
Biomarker analyses in caged and wild fish suggest exposure to pollutants in an urban area with a landfill
Authors: Hanson Niklas , Larsson Åke
Published: January 2010

An unexpectedly high frequency of skeletal deformations in brown trout has previously been observed in the brook Vallkärrabäcken in southern Sweden. Environmental pollutants from storm water and leachate from an old landfill have been suggested as responsible for the observed deformations. Biomarkers in farmed rainbow trout, placed in tanks with water supplied from the brook, were used to investigate if exposure to pollutants may induce toxic responses in fish. Furthermore, biomarkers were also measured in wild brown trout that were caught in the brook. The most important finding was that the hepatic ethoxyresorufin‐O‐deethylase (EROD) activity was five to seven times higher for rainbow trout and brown trout in exposed areas compared to reference sites (P < 0.001). Analyses of bile in rainbow trout showed that the concentration of PAH‐metabolites was two to three times higher (P < 0.001) in the exposed areas. However, due to their smaller size and the feeding status, only insufficient amounts of bile could be retrieved from the wild brown trout. The study provides evidence for pollution in parts of Vallkärrabäcken. It is therefore possible that the previously observed high frequency of skeletal damage have been caused by pollutants. The methodology with farmed rainbow trout in flow through tanks worked well and provided more information about the occurrence of pollutants in Vallkärrabäcken than the data from brown trout. The main reasons for this were that the size and the feeding status of the fish could be controlled. This allowed a total of 21 biomarkers to be analyzed in farmed rainbow trout compared to only five in wild brown trout. Furthermore, the use of farmed fish eliminates the risk of migration, which may otherwise bias the data when wild fish are used. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2011.
Effectiveness of cerclage according to severity of cervical length shortening: a meta‐analysis
Authors: Berghella V. , Keeler S. M. , To M. S. , Althuisius S. M. , Rust O. A.
Published: January 2010

Objectives

To estimate the effectiveness of cerclage according to degree of cervical length (CL) shortening.

Methods

A meta‐analysis was carried out of trials of women with singleton gestations and second‐trimester transvaginal sonographic CL < 25 mm randomized to cerclage or no cerclage. The degree of CL shortening was correlated to the efficacy of cerclage in preventing preterm birth.

Results

There was a significant reduction in preterm birth < 35 weeks in the cerclage compared with no cerclage groups in 208 singleton gestations with both a previous preterm birth and CL < 25 mm (relative risk, 0.61; 95% CI, 0.40–0.92). In these women, preterm birth < 37 weeks was significantly reduced with cerclage for CL ⩽ 5.9 mm, ⩽ 15.9 mm, 16–24.9 mm and < 25 mm. None of the analyses for 344 women without a previous preterm birth was significant.

Conclusions

Cerclage, when performed in women with a singleton gestation, previous preterm birth and cervical length < 25 mm, seems to have a similar effect regardless of the degree of cervical shortening, including CL 16–24 mm, as well as CL ⩽ 5.9 mm. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Placental growth factor in the first trimester: relationship with maternal factors and placental Doppler studies
Authors: Kasdaglis T. , Aberdeen G. , Turan O. , Kopelman J. , Atlas R. , Jenkins C. , Blitzer M. , Harman C. , Baschat A. A.
Published: January 2010

Objective

Placental growth factor (PlGF) is a potent angiogenic factor that impacts on early placental vascular development. It was our aim to clarify relationships between PlGF and first‐trimester maternal/placental factors that are related to placental development.

Methods

Prospectively enrolled patients at 11–14 weeks' gestation had serum PlGF measurement by enzyme‐linked immunosorbent assay. Results were related to maternal age, parity, race, body mass index, mean arterial blood pressure (MAP), smoking/caffeine use and parameters of placental blood flow resistance.

Results

In 110 consecutive patients PlGF levels ranged between 1.0 and 176.1 pg/mL, showing a linear relationship with gestational age (GA) (PlGF = (1.4251 × GA) −74.951, r2 = 0.0765, F = 8.941, P = 0.03). PlGF did not relate to maternal demographics but negatively correlated with MAP (Spearman rho = −0.191, P < 0.05). Bilateral uterine artery notching was associated with lower PlGF (40.7 (range, 1.01–131.6) vs. 51.1 (range, 6.4–176.1) pg/mL; Mann–Whitney P = 0.034.). A trend to lower levels was also observed when umbilical artery end‐diastolic flow was absent (37.1 (range, 6.8–95) vs. 49.3 (range, 1.01–176.1) pg/mL; P = 0.05).

Conclusion

PlGF in the first trimester is related to maternal cardiovascular factors and placental Doppler findings that are associated with subsequent placental dysfunction. The utility of this parameter as a first‐trimester screening tool on a population basis requires further investigation. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
A technical tip on scanning obese gravidae
Authors: Benacerraf B. R.
Published: January 2010

How do we do it?

Practical advice on imaging‐based techniques and investigations
A new case of GABA transaminase deficiency facilitated by proton MR spectroscopy
Authors: Tsuji Megumi , Aida Noriko , Obata Takayuki , Tomiyasu Moyoko , Furuya Noritaka , Kurosawa Kenji , Errami Abdellatif , Gibson K. Michael , Salomons Gajja S. , Jakobs Cornelis , Osaka Hitoshi
Published: January 2010

Background

Deficiency of 4‐aminobutyrate aminotransferase (GABA‐T) is a rare disorder of GABA catabolism, with only a single sibship reported. We report on a third case, a Japanese female infant with severe psychomotor retardation and recurrent episodic lethargy with intractable seizures, with the diagnosis facilitated by proton magnetic resonance (MR) spectroscopy (1H‐MRS).

Methods

Neuroimaging was performed at the first episode of lethargy. For 1H‐MRS, locations were placed in the semioval center and the basal ganglia. Quantification of metabolite concentrations were derived using the LCModel. We confirmed the diagnosis subsequently by enzyme and molecular studies, which involved direct DNA sequence analysis and the development of a novel multiplex ligation‐dependent probe amplification test.

Results

1H‐MRS analysis revealed an elevated GABA concentration in the basal ganglia (2.9 mmol/l). Based on the results of quantitative 1H‐MRS and clinical findings, GABA‐T deficiency was suspected and confirmed in cultured lymphoblasts. Molecular studies of the GABA‐T gene revealed compound heterozygosity for a deletion of one exon and a missense mutation, 275G>A, which was not detected in 210 control chromosomes.

Conclusions

Our results suggest that excessive prenatal GABA exposure in the central nervous system (CNS) was responsible for the clinical manifestations of GABA transaminase deficiency. Our findings suggest the dual nature of GABA as an excitatory molecule early in life, followed by a functional switch to an inhibitory species later in development. Furthermore, quantitative 1H‐MRS appears to be a useful, noninvasive tool for detecting inborn errors of GABA metabolism in the CNS.
Phytoplankton community similarity in a semiarid floodplain under contrasting hydrological connectivity regimes
Authors: Angeler David G. , Alvarez‐Cobelas Miguel , Rojo Carmen , Sánchez‐Carrillo Salvador
Published: January 2010

In this study we compare phytoplankton community similarity between sites in a semiarid floodplain wetland over a 6‐year period with variable hydroperiod and connectivity regimes. Phytoplankton communities showed a relatively high site idiosyncrasy during most parts of the study; however, during situations of low connectivity when individual sites were highly fragmented, phytoplankton communities occasionally became more similar between sites. This suggests that mass effects related to dispersal‐mediated processes could be important. Viewed from a metacommunity perspective, phytoplankton community assembly at the wetland scale involves complex hierarchical processes that can act independently at different spatial extents. The main conclusion of this study is that the well‐known effects of environmental variability associated with hydrological disturbance alone may not be sufficient for explaining, and by extension predicting, community assembly in this wetland. Other processes, perhaps involving overland dispersal, may eventually add a new dimension to, and complicate our understanding of, community processes in fluctuating wetlands.
Dispersal of four fritillary butterflies within identical landscape
Authors: Fric Zdenek , Hula Vladimir , Klimova Martina , Zimmermann Kamil , Konvicka Martin
Published: January 2010

Both species‐specific traits and landscape configuration, such as area and connectivity of habitat patches plus the character of uninhabitable matrix, affect animal movements in fragmented landscapes. Difficulties with disentangling species‐specific and landscape effects have obscured comparisons among species, hindering the understanding of dispersal in metapopulations. To circumvent this complication, we performed a mark–recapture study of four related nymphalid butterflies within identical landscape and in single season. The studied species were three Melitaeinae checkerspots (Euphydryas aurinia,Melitaea athalia,Melitaea diamina) and one Argynnini fritillary (Brenthis ino). Applying the Virtual Migration model revealed that (1) except for mortality within habitat, model parameters differed from those found for the studied species elsewhere; (2) the three Melitaeinae species were more akin in movement parameters than the Argynnini representative (i.e.,B. ino); (3) within Melitaeinae, differences between sexes were more prominent than differences among species; (4) Melitaeinae males left natal patches more readily than females, while the opposite applied toB. ino; (5) males ofM. diaminaand both sexes ofB. inoexhibited highest values of dispersal mortality; (6) except for females ofM. diaminaand both sexes ofB. ino, immigration and emigration scaled with area in females but not in males. Finding (1) demonstrates that geometry of habitat network affects mobility considerably and that transferring dispersal parameters across systems is unwarranted. Still, (2–6) demonstrate that within identical networks, related species follow similar dispersal patterns, suggesting that conservation scenarios suitable for a well‐studied model species would suite related species as well.
Estimating peer effects in sexual behavior among adolescents
Authors: Ali Mir M. , Dwyer Debra S.
Published: January 2010

In this paper we seek to empirically quantify the role of peer social networks in influencing sexual behavior among adolescents. Using data of a nationally representative sample of adolescents we utilize a multivariate structural model with school‐level fixed effects to account for the problems of contextual effects, correlated effects and peer selections to purge the potential biases from the estimates of peer influence. Our peer group measures are drawn not only from the nomination of close friends, but also from classmates. Controlling for parent level characteristics, and other demographic parameters, we find that a 10% increase in the proportion of close friends who initiates sex increases the probability that an individual chooses to initiate sex by 5% and a 10% increase in number of sexual partners among close friends increases an individual's sexual partner by 5%. The influence of classmates however, diminishes in magnitude after accounting for unobserved environmental confounders.
Dual resonance in vortex-induced vibrations at subcritical and supercritical Reynolds numbers
Authors: DAHL J. M. , HOVER F. S. , TRIANTAFYLLOU M. S. , OAKLEY O. H.
Published: January 2010

An experimental study is performed on the vortex induced vibrations of a rigid flexibly mounted circular cylinder placed in a crossflow. The cylinder is allowed to oscillate in combined crossflow and in-line motions, and the ratio of the nominal in-line and transverse natural frequencies is varied systematically. Experiments were conducted on a smooth cylinder at subcritical Reynolds numbers between 15 000 and 60 000 and on a roughened cylinder at supercritical Reynolds numbers between 320 000 and 710 000, with a surface roughness equal to 0.23 % of the cylinder diameter. Strong qualitative and quantitative similarities between the subcritical and supercritical experiments are found, especially when the in-line natural frequency is close to twice the value of the crossflow natural frequency. In both Reynolds number regimes, the test cylinder may exhibit a ‘dual-resonant’ response, resulting in resonant crossflow motion at a frequencyfv, near the Strouhal frequency, and resonant in-line motion at 2fv. This dual resonance is shown to occur over a relatively wide frequency region around the Strouhal frequency, accompanied by stable, highly repeatable figure-eight cylinder orbits, as well as large third-harmonic components of the lift force. Under dual-resonance conditions, both the subcritical and the supercritical response is shown to collapse into a narrow parametric region in which the effective natural-frequency ratio is near the value 2, regardless of the nominal natural-frequency ratio. Some differences are noted in the magnitudes of forces and the cylinder response between the two different Reynolds number regimes, but the dual-resonant response and the resulting force trends are preserved despite the large Reynolds number difference.
Cognitive functioning in chronic fatigue syndrome: a meta-analysis
Authors: Cockshell S. J. , Mathias J. L.
Published: January 2010

Background

Cognitive problems are commonly reported in persons with chronic fatigue syndrome (CFS) and are one of the most disabling symptoms of this condition. A number of cognitive deficits have been identified, although the findings are inconsistent and hindered by methodological differences. The current study therefore conducted a meta-analysis of research examining cognitive functioning in persons with CFS in order to identify the pattern and magnitude of any deficits that are associated with this condition.

Method

A comprehensive search of the PubMed and PsycINFO databases for studies that examined cognitive functioning in CFS between 1988 and 2008 identified 50 eligible studies. Weighted Cohen's d effect sizes, 95% confidence intervals and fail-safe Ns were calculated for each cognitive score.

Results

Evidence of cognitive deficits in persons with CFS was found primarily in the domains of attention, memory and reaction time. Deficits were not apparent on tests of fine motor speed, vocabulary, reasoning and global functioning.

Conclusions

Persons with CFS demonstrate moderate to large impairments in simple and complex information processing speed and in tasks requiring working memory over a sustained period of time.
Clerical Misconduct in the Church of Sweden 2000–2004
Authors: Hansson Per
Published: January 2010

The Church of Sweden, being the national Lutheran Church, was disestablished in 2000 and former state obligations were transferred to the church. Major changes were effected in the oversight of the clergy and all complaints were thereafter to be handled by the church itself. This article considers empirical data concerning those complaints and makes an evaluative comparison with the previous system.
Ministerial Duty and Professional Discipline in the Anglican Church of Australia
Authors: Blake Garth
Published: January 2010

This article considers the question whether ministry in the Anglican Church of Australia is a profession as well as a vocation. After considering the context of child sexual abuse in the Church, and the contemporary practice of ministry, it examines whether it exhibits the four commonly recognised sociological marks of a profession: (1) specialised knowledge and skills; (2) service of fundamental human needs; (3) commitment to the other's best interest; and (4) structures for accountability.
Molecular mechanisms underlying nutrient-stimulated incretin secretion
Authors: Parker Helen E. , Reimann Frank , Gribble Fiona M.
Published: January 2010

The incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are released from enteroendocrine cells in the intestinal epithelium in response to nutrient ingestion. The actions of GLP-1 and GIP – not only on local gut physiology but also on glucose homeostasis, appetite control and fat metabolism – have made these hormones an attractive area for drug discovery programmes. The potential range of strategies to target the secretion of these hormones therapeutically has been limited by an incomplete understanding of the mechanisms underlying their release. The use of organ and whole-animal perfusion techniques, cell line models and primary L- and K-cells has led to the identification of a variety of pathways involved in the sensing of carbohydrate, fat and protein in the gut lumen. This review focuses on our current understanding of these signalling mechanisms that might underlie nutrient responsiveness of L- and K-cells.
Daten zum Übergewicht und zu Ernährungsgewohnheiten aus der Schweizerischen Gesundheitsbefragung 2007
Authors: Eichholzer  , Bovey  , Jordan  , Probst-Hensch  , Stoffel-Kurt
Published: January 2010

Das Bundesamt für Statistik führt im Abstand von fünf Jahren Schweizerische Gesundheitsbefragungen (SGB) durch. Die hier vorgestellte SGB07 ist die vierte vergleichbare Erhebung. Die fast 19 000 Personen umfassende Stichprobe ist repräsentativ für die in der Schweiz wohnhafte Bevölkerung ab 15 Jahren. Übergewicht (29%) und Adipositas (8%) sind weit verbreitet, aber seit 2002 sind keine signifikanten Zunahmen mehr zu verzeichnen. Männer sind deutlich häufiger übergewichtig als Frauen (38% vs. 21%). Bezüglich Ernährungsgewohnheiten geben knapp 30% der Befragten an, auf nichts zu achten in ihrer Ernährung. Die empfohlenen fünf Portionen Früchte und Gemüse pro Tag konsumieren nur 30%, die empfohlenen drei Portionen Milch und Milchprodukte nur 10%. 37% essen selten oder nie Fisch, und der tägliche Fleisch/Wurstwarenkonsum liegt bei knapp 20%. Grobe Längsvergleiche der vier SGB ergeben nur geringe Verbesserungen im Essverhalten über die letzten 15 Jahre.
Abdominaler Tumor nach anhaltendem Husten und entgleister Antikoagulation
Authors: Wandeler-Meyer  , Bremerich  , Christ
Published: January 2010

Wir berichten über eine 83-jährige Patientin mit einem STEMI (ST elevation myocardial infarction), welche unter der Thrombozytenaggregationshemmung und systemischen Antikoagulation ein Rektusscheidenhämatom nach einer Hustenattacke entwickelte. Die Patientin beklagte progrediente Schmerzen im linken Unterbauch, welche mit einer palpablen Raumforderung einhergingen und von einer Anämie begleitet waren. In der Abdomensonographie und der Computertomographie zeigte sich ein Rektusscheidenhämatom. Der Artikel erörtert Pathogenese, Klinik, Diagnostik und Therapie unter Berücksichtigung der aktuellen Literatur.
Origin of the smooth zone in early Cretaceous North Atlantic magnetic anomalies
Authors: Tominaga Masako , Sager William W.
Published: January 2010

Late Jurassic‐Early Cretaceous marine magnetic anomalies observed in the North Atlantic exhibit an abrupt change in character in M5‐M15 crust. The anomalies are smoother with low amplitudes, and are difficult to correlate among nearby profiles. The accepted explanation for the origin of this smooth zone is diminished resolution and anomaly interference due to slow spreading rates, which narrows the widths of polarity reversals in the crust and causes interference among sea‐surface anomalies. Magnetic modeling of these anomalies indicates that neither slow spreading rates alone nor slow spreading rates in combination with a decrease in geomagnetic field intensity can explain the basic character of the smooth zone. Combined with other geophysical evidence, our study suggests that one consequence of slow spreading rates that is responsible for the magnetic “smooth zone” is a thinned crustal basalt layer or a non‐basaltic magnetic source layer resulting from low melt supply during a period of ultra‐slow spreading.