bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and two‐photon absorption properties of conjugated polymers with N‐arylpyrrole as conjugated bridge and isolation moieties
Authors: Li Qianqian , Huang Jing , Pei Zhiguo , Zhong Aoshu , Peng Ming , Liu Jun , Huang Zhenli , Qin Jingui , Li Zhen
Published: April 2011

Three novel conjugated polymers with N‐arylpyrrole as the conjugated bridge were designed and synthesized, which emitted strong one‐ or two‐photon excitation fluorescence in dilute tetrahydrofuran (THF) solution with high quantum yields. The maximal two‐photon absorption (TPA) cross‐sections of the polymers, measured by the two‐photon‐induced fluorescence method using femtosecond laser pulses in THF, were 752, 1114, and 1869 GM, respectively, indicating that the insertion of electron‐donating or electron‐withdrawing moieties into the polymer backbone could benefit to the increase of the TPA cross‐section. Their large TPA cross‐sections, coupled with the relatively high emission quantum yields, made these conjugated polymers attractive for practical applications, especially two‐photon excited fluorescence. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Dendritic surface functionalization of biodegradable polymer assemblies
Authors: Nazemi Ali , Amos Ryan C. , Bonduelle Colin V. , Gillies Elizabeth R.
Published: April 2011

The functionalization of nanomaterials with dendritic surface moieties was recently demonstrated to be an effective means of displaying biological ligands and potentially modulating the biological properties of these materials. With the aim of extending this surface functionalization approach to biodegradable polymer assemblies, poly(ethylene oxide)‐polycaprolactone (PEO‐PCL) block copolymers with terminal azide or methoxy groups were prepared and were assembled to form micelles or vesicles with varying loadings of surface azides. Dendrons bearing peripheral amines, guanidines, or hydroxyls were prepared and conjugated to the assemblies, and the conjugation yields were measured and compared as a function of azide loading and assembly type (micelle versus vesicle). A small molecule rhodamine derivative was also conjugated, allowing the effect of sterics to be studied. The effects of the surface functionalization on the aggregation state of the assemblies were studied by light scattering and transmission electron microscopy. Overall, the results revealed interesting differences between the two systems with respect to both the reaction yields and the stabilities. Furthermore, micelles functionalized with dendrons bearing peripheral guanidines were found to exhibit enhanced cell uptake relative to control micelles, demonstrating that this approach can be used to modulate the biological properties of the materials. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Elucidating the reaction mechanism of the benzoate oxidation pathway encoded aldehyde dehydrogenase from Burkholderia xenovorans LB400
Authors: Bains Jasleen , Leon Rafael , Temke Kevin G. , Boulanger Martin J.
Published: April 2011

Oxidation of cis‐3,4‐dehydroadipyl‐CoA semialdehyde to cis‐3,4‐dehydroadipyl‐CoA by the aldehyde dehydrogenase, ALDHC (EC.1.2.1.77), is an essential step in the metabolism of benzoate in Burkholderia xenovorans LB400. In a previous study, we established a structural blueprint for this novel group of ALDH enzymes. Here, we build significantly on this initial work and propose a detailed reaction mechanism for ALDHC based on comprehensive structural and functional investigations of active site residues. Kinetic analyses reveal essential roles for C296 as the nucleophile and E257 as the associated general base. Structural analyses of E257Q and C296A variants suggest a dynamic charge repulsion relationship between E257 and C296 that contributes to the inherent flexibility of E257 in the native enzyme, which is further regulated by E496 and E167. A proton relay network anchored by E496 and supported by E167 and K168 serves to reset E257 for the second catalytic step. We also propose that E167, which is unique to ALDHC and its homologs, serves a critical role in presenting the catalytic water to the newly reset E257 such that the enzyme can proceed with deacylation and product release. Collectively, the reaction mechanism proposed for ALDHC promotes a greater understanding of these novel ALDH enzymes, the ALDH super‐family in general, and benzoate degradation in B. xenovorans LB400.
Field trial measuring the compatibility of methoxyfenozide and flonicamid with Orius laevigatus Fieber (Hemiptera: Anthocoridae) and Amblyseius swirskii (Athias‐Henriot) (Acari: Phytoseiidae) in a commercial pepper greenhouse
Authors: Colomer Ignacio , Aguado Pedro , Medina Pilar , Heredia Rosa María , Fereres Alberto , Belda José Eduardo , Viñuela Elisa
Published: April 2011

BACKGROUND: Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) and Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) are among the most serious pests of sweet peppers in greenhouses. Chemical control is difficult because of their high reproductive rates and insecticide resistance, and seasonal inoculative releases of Orius laevigatus (Fieber) and Amblyseius swirskii (Athias‐Henriot) are commonly used to reduce their populations. As chemical treatments are often needed in the crop against other pests, the side effects of methoxyfenozide (an insect growth regulator against lepidopteran pests) and flonicamid (a selective feeding inhibitor against sucking insects) were studied in both beneficial organisms in a commercial greenhouse.

RESULTS: Orius laevigatus and A. swirskii were released at commercial rates (4–5 and 100 m−2), and a strong establishment and a very homogeneous distribution were reached. One pesticide treatment with the maximum field recommended concentration of methoxyfenozide and flonicamid (96 and 100 mg AI L−1) was done when they were well established, and their population levels were not affected either immediately or up to 30 days after treatment.

CONCLUSION: The results are indicative of no impact of methoxyfenozide and flonicamid on the two natural enemies in the field, and both can be considered as potential alternatives to be included in IPM programmes in sweet pepper. Copyright © 2011 Society of Chemical Industry
Protective effect of recombinant human glucagon‐like peptide‐1 (rhGLP‐1) pretreatment in STZ‐induced diabetic mice
Authors: Wu Ye‐Lin , Huang Jing , Liu Jian , Jin Ming‐Fei , Gu Mei , Hong Yiguo , Wu Zi‐Rong
Published: April 2011

Human glucagon‐like peptide‐1 (hGLP‐1) and its mimetics have emerged as therapies for type 2 diabetes. However, clinical treatment of diabetes with hGLP‐1 is ineffective because of rapid DPPIV‐mediated hGLP‐1 degradation in the circulation. In this study, we investigated the protective effect of recombinant human glucagon‐like peptide‐1 (rhGLP‐1) treatment on STZ‐induced diabetic mice. Mice were treated daily with rhGLP‐1 (24 nmol/kg body weight) starting before or after STZ injection (40 mg/kg body weight) to induce diabetes. Mice pretreated with rhGLP‐1 before but not after STZ showed significantly reduced blood glucose levels (P < 0.05), increased oral glucose tolerance (area under the curve, 1740 ± 71.18 vs 2416 ± 205.6, P < 0.05). Furthermore, the bioproduct of lipid peroxidation, MDA, was reduced and SOD and GSH‐PX activities were enhanced globally and in pancreas of mice that received rhGLP‐1 pretreatment before STZ, when comparing with STZ‐treated mice. Finally, STZ‐induced pancreatic islet damage was rescued by rhGLP‐1 pretreatment. Taken together, the results of this study demonstrate that rhGLP‐1 pretreatment has a protective effect against STZ‐induced diabetes in mice. These findings suggest that the GLP‐1 pretreatment may be a new therapeutic strategy in the preventive and protective treatment during diabetes initiation and progression. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
Synthesis and biological evaluation of analogues of the marine cyclic depsipeptide obyanamide
Authors: Zhang Wei , Ding Ning , Li Yingxia
Published: April 2011

On the basis of the total synthesis of obyanamide, 20 analogues of this marine cyclic depsipeptide have been synthesized by (i) preparation of the tripeptide fragments in the western hemisphere using Z/OtBu protocol; (ii) preparation of the dipeptide fragments in the eastern hemisphere using Boc/OMe protocol; and (iii) fragments coupling, removal of protecting groups (Boc and OtBu, in one pot), and macrocyclizaion in the last step. The cytotoxic test showed that three synthetic compounds exhibited moderate activities against HL‐60, KB, LOVO, and A549 cell lines. According to the results, the β‐amino acid residue was found to play a critical role in the biological activities. Additionally, the ester bond along with the Ala(Thz) moiety was also essential for biological activities. However, it seems too early to draw a conclusion that the N‐methylation of Val/Phe can lead to higher or lower cytotoxic activities. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
A fundamental requirement for crystal‐field parametrization
Authors: Mulak Jacek , Mulak Maciej
Published: April 2011

The physically correct parametrization of the energy levels of transition ions in crystals in terms of crystal‐field (CF) Hamiltonians ${\cal H}_{{\rm CF}} = \sum\nolimits_{k} {} \sum\nolimits_{q} {} B_{kq} C_{q}^{(k)} $ has to be based on the CF parameters Bkq that lead to the correct CF splitting second moments, both the global one σ and the partial ones σk. Only such parametrizations correspond to the appropriate multipolar structure of the surrounding CF. Each parametrization being characterized by its own multipolar CF strengths $S_{k} = [1/(2k + 1)\sum\nolimits_{q} {|B_{kq} |^{2} } ]^{1/2} $, for k = 2, 4, and 6, yields a definite second moment σ, which can be derived from the additivity relationship $\sigma {}^{2} = \sum\nolimits_{k} {} \sigma _{k}^{2} = 1/(2J + 1)\sum\nolimits_{k} {S_{k}^{2} (\langle J||C^{(k)} ||J\rangle )^{2} } $, and the known asphericities $\langle \Psi ||C^{(k)} ||\Psi \rangle $ of the central‐ion eigenfunctions Ψ. The condition σ = σexp must be satisfied to ensure the parametrization's correctness. However, our survey of literature indicates that there exists many other well‐fitted CF parameter sets that do not obey this condition. Therefore, such sets are erratic and non‐physical, and should be re‐examined or rejected. Having σ for several (≥3) eigenstates $|\Psi \rangle $ along with the relevant $\langle \Psi ||C^{(k)} ||\Psi \rangle $ asphericities, one can estimate σk and Sk, which are well founded experimentally. The above findings set up the parametrization process properly. Lack of consistency between the second moments representing various parametrizations and the pertinent second moments observed in experiments is presumably the main reason for deluge of formally accurate but accidental and inequivalent parametrizations.
Elastic properties and inter‐atomic bonding in layered Fe–Cu arsenide oxide Sr2Fe2CuAs2O2
Authors: Shein Igor R. , Bannikov Vyacheslav V. , Ivanovskii Alexander L.
Published: April 2011

Inspired by recent discovery of the layered five‐component phase – the tetragonal arsenide oxide Sr2Fe2CuAs2O2uniting two types of [Fe2As2] and [CuO2] blocks, which are the main building blocks inherent in two basic families of high‐TCsuperconductors: so‐called cuprates and iron‐pnictides, we used the first principles calculations to predict the elastic properties and to find their interplay with inter‐atomic bonding for this unique system. Our data reveal that the examined phase is a relatively soft material; the predicted bulk and shear modules are about 90 and 54 GPa, respectively. Besides, this system is mechanically stable, adopts considerable elastic anisotropy, and should demonstrate brittleness. These conclusions agree with the bonding picture for Sr2Fe2CuAs2O2, according to which the inter‐atomic bonding in this system is highly anisotropic and includes ionic, covalent, and metallic contributions, where inside [Fe2As2] and [CuO2] blocks covalent‐ionic Fe–As, Cu–O and metallic‐like Fe–Fe bonds take place, whereas inter‐blocks bonding is basically of the ionic type.
Modeling magnetism of hexagonal Fe monolayers on 4d substrates
Authors: Al‐Zubi A. , Bihlmayer G. , Blügel S.
Published: April 2011

Mapping the total energies obtained from first principles calculations to model Hamiltonians is a powerful technique to explore the magnetic ground state of a system. We analyze the applicability of this approach in the presence of highly polarizable substrates, e.g. for an ultrathin Fe layer on Pd(111), Rh(111), Ru(0001), or Tc(0001). We find that the traditionally accepted model Hamiltonians (Heisenberg plus nearest neighbor higher‐order spin Hamiltonians) are not sufficient to capture the magnetic interactions in these systems and examine new terms that can be included to improve the description. Challenges for this technique are exemplified by the double‐rowwise antiferromagnetic (AFM) ground state predicted for Fe/Rh(111).
Non‐linear magnetoelastic coupling in monolayers: Experimental challenges and theoretical insights
Authors: Sander Dirk , Kirschner Jürgen
Published: April 2011

Recent results of experimental studies on magnetoelastic coupling in epitaxial monolayers are compiled and discussed in view of theoretical work. The observation of non‐bulk like magnetoelastic coupling in strained systems in experiment and theory is ascribed to an effective and strain‐dependent magnetoelastic coupling. It is described as a second‐order strain contribution to the energy density. We comment on the importance of inhomogeneous strain and of its relaxation for the magnetic anisotropy of nanostructures.
Mn3−xGa (0 ≤ x ≤ 1): Multifunctional thin film materials for spintronics and magnetic recording
Authors: Kurt H. , Rode K. , Venkatesan M. , Stamenov P. , Coey J. M. D.
Published: April 2011

Tetragonal Mn3−xGa (0 ≤ x ≤ 1) epitaxial films possess exceptional magnetic and electronic properties. Stoichiometric Mn3Ga crystallizes in the D022 structure (abstract figure) and is a collinear ferrimagnet with an easy c‐axis. It exhibits a unique combination of low magnetization, high uniaxial anisotropy, high Curie temperature and high spin polarization, which suit the requirements for spin torque memories down to 10 nm in size. Mn2Ga, on the other hand, exhibits much higher magnetization, high perpendicular anisotropy and high Curie temperature but a lower spin polarization, which make it a potential candidate for high density bit‐patterned recording with areal densities up to 10 Tb inch−2 (∼15 kb µm−2) and 10‐year thermal stability. The flexibility of the D022 structure allows a variety of magnetic materials to be synthesized with varying x to suit specific magnetic applications. Hexagonal D019‐Mn3Ga films are antiferromagnetic, which could be useful for exchange bias.

magnified image

(a) The tetragonal D022 unit cell of Mn3Ga. Ga atoms are ordered in a body‐centred tetragonal structure and Mn atoms occupy 2b (red) and 4d (green) sites. (b) The hexagonal D019 unit cell of Mn3Ga.
Sorption Phenomena in Packaged Foods: Factors Affecting Sorption Processes in Package–Product Systems
Authors: Caner C.
Published: April 2011

Sorption process can readily occur from many foods. The sorption behaviours result in loss of food quality and shelf life of the packaged foods by altering the aroma compound profile. Although the intensity of the aroma of a packaged foodstuff depends on the vapour pressure, the interaction of the volatile organic moieties with other food constituents and the aroma barrier characteristics of the package, the nature of the aroma is also imperative in determining the extent of sorption. Sorption properties are largely determined by packaging characteristics, flavour molecules properties, food matrix composition and environmental conditions. The chemical composition, chain stiffness, morphology, polarity and crystallinity of the polymer influence flavour absorption as much as the chemical composition, concentration and polarity of the flavour compounds, as well as the presence of other chemical constituents. External factors such as duration of storage, relative humidity, temperature and the presence of other food components can also affect the solubility of aroma compounds in packaged foods. Factors relating to both chemical and physical structure of flavour, food and packaging influence the degree of sorption and also the sorption pattern. Sorption from the packaged foods is of major concern in the selection and use of plastic packaging materials for food packaging. The present review highlights some of the major factors influencing the sorption process. The scientific principles related to sorption are reviewed and distinguished. Copyright © 2011 John Wiley & Sons, Ltd.
PCM study of the solvent and substituent effects on bond dissociation energies of the ONO Bond—A DFT study
Authors: Xiaohong Li , Xianzhou Zhang
Published: April 2011

A PCM continuum model, at the B3LYP, B3P86, and B3PW91 three‐parameter hybrid DFT methods with 6‐311G** basis set, is used to study the bond dissociation energies (BDEs) of benzyl nitrites. Compared the computed results with the experimental values, it is noted that B3PW91 functional is the best method to compute the BDEs of benzyl nitrites. The solvent and substituent effects on the BDEs of the ONO bond are analyzed, and it is shown that the BDE of the ONO bond decreases with the increment of the Hammett constants of substituent groups on benzene for benzyl nitrites except C6H5CH2ONO. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
REMOVAL OF AQUATIC WEEDS GREATLY ENHANCES FISH COMMUNITY RICHNESS AND DIVERSITY: AN EXAMPLE FROM THE BURDEKIN RIVER FLOODPLAIN, TROPICAL AUSTRALIA
Authors: Perna C. N. , Cappo M. , Pusey B. J. , Burrows D. W. , Pearson R. G.
Published: April 2011

Hydrological changes associated with irrigation, in conjunction with increased nutrient concentrations and aquatic plant densities, have greatly impacted fish habitat values on the Burdekin River floodplain. The two most significant weeds in the Burdekin floodplain are water hyacinth (Eichhornia crassipes) and para grass (Urochloa mutica). Water hyacinth creates a base for the para grass (and then other weeds) to grow out into deeper water, creating weed mats that can then only be removed by mechanical means or floods of the largest magnitude. We attempted to rehabilitate floodplain lagoons by the mechanical removal of floating weed mats and monitored the result by measuring the subsequent effects on fish habitats and fish communities. Prior to weed removal, fish habitats were generally of poor quality, and fish community structure was skewed away from rich native assemblages to depauperate communities dominated in some instances by alien species. Poor water quality arising from floating weed mats is considered to be the main determinant of reduced fish abundance and diversity. After mechanical weed removal, recovery of water quality and physical habitat led to the re‐establishment of many native fish species. Key refuge habitats within the distribution channels were a critical source of recruits for fishes dispersing during times of elevated seasonal flows into the newly rehabilitated reaches. This study demonstrates that floating alien weed mats have significant negative effects upon aquatic communities and that mechanical removal of these weed mats (as opposed to chemical removal) results in dramatic improvements in native fish species richness and abundance. Copyright © 2011 John Wiley & Sons, Ltd.
VEGETATION–LANDFORM ASSEMBLAGES ALONG SELECTED RIVERS IN THE CZECH REPUBLIC, A DECADE AFTER A 500‐YEAR FLOOD EVENT
Authors: Loučková B.
Published: April 2011

Rivers with a natural flow regime strongly influence the dynamics of riparian plant communities through hydrological and geomorphological processes. In this study, associations between fluvial landforms and vegetation are investigated on three near‐natural rivers in the Czech Republic a decade after a 500‐year return period flood in July 1997. This extreme disturbance destroyed the anthropogenically modified river channels and created suitable conditions for a range of ecosystems with high diversity and ecological stability. Field surveys were conducted on fluvial landforms (bars, islands, banks, floodplains and terraces) along three ‘renaturalized’ rivers, where no technical modifications had subsequently been made to their channels outside urban areas and the floodplains had been left in a post‐flood state. Vegetation species abundance and 13 environmental variables (topographical, hydrological and soil) were investigated in summer 2007, 10 years after the extreme flood disturbance. The results suggest that the recently created fluvial geomorphic forms are key environmental determinants of riparian vegetation distribution patterns. A range of statistical analyses illustrate that some plant species show predictable patterns of occurrence that correspond with the fluvial forms, supporting a fourfold grouping of herbaceous and woody species and the identification of typical plant communities associated with gravel bars, islands, banks, floodplains and terraces. An investigation of the species richness found on different fluvial landforms showed that the highest number of species occurred on the floodplain and decreased gradually towards the channel bed and towards terraces. Investigation of existing conditions in reaches of rivers with natural dynamics of fluvial processes provides valuable information that can be used as an effective tool for planning restoration strategies and precise management. However, the most important finding of this study is the remarkable establishment of complex river corridor vegetation–landform associations within 10 years of a 500‐year flood that removed the heavily cultivated landscape that had existed before the event. Copyright © 2011 John Wiley & Sons, Ltd.
Self‐Assembly: I‐Motif Nanospheres: Unusual Self‐Assembly of Long Cytosine Strands (Small 8/2011)
Authors: Zikich Dragoslav , Liu Ke , Sagiv Lior , Porath Danny , Kotlyar Alexander
Published: April 2011

The synthesis and characterization of novel DNA structures based on tetraplex cytosine (C) arrangements, known as i‐motifs or i‐tetraplexes, is reported. Atomic force microscopy (AFM) investigation shows that long C‐strands in mild acidic conditions form compact spherically shaped nanostructures. The DNA nanospheres are characterized by a typical uniform shape and narrow height distribution. Electrostatic force microscopy (EFM) measurements performed on the i‐motif spheres clearly show their electrical polarizability. Further investigations by scanning tunneling microscopy (STM) at ultrahigh vacuum reveals that the structures exhibit an average voltage gap of 1.9 eV, which is narrower than the voltage gap previously measured for poly(dG)–poly(dC) molecules in similar conditions.
Corrosion Behavior of TiC Particle‐Reinforced 2Cr13 Stainless Steel
Authors: Wu Qianlin , Li Wenge , Yin Yansheng
Published: April 2011

The corrosion behavior of TiC particle‐reinforced 2Cr13 stainless steels prepared by in situ reaction and electroslag remelting (ESR) was investigated using potentiodynamic polarisation measurements and immersion tests. The addition of TiC particles to 2Cr13 stainless steel impeded rapid pit propagation but maintained a high corrosion rate in the whole immersion time investigated. The TiC addition developed finer matrix structure, the formation of Cr‐rich carbides and high dislocation density around the TiC particles before corrosion, which results in an increasing corrosion rate and preferential pitting attack at the steel matrix/TiC interface. Although the corrosion resistance of 2Cr13 stainless steel is sharply decreased due to TiC addition, it is significantly improved after the ESR process. This is attributed to the more uniform distribution and smaller size of TiC particles, the increase of value of χ in TiCχ and the elimination of the porosity in TiC particle‐reinforced 2Cr13 stainless steel after the ESR process.
Differentiation of Induced Pluripotent Stem Cells of Swine into Rod Photoreceptors and Their Integration into the Retina
Authors: Zhou Liang , Wang Wei , Liu Yongqing , de Castro Juan Fernandez , Ezashi Toshihiko , Telugu Bhanu Prakash V.L. , Roberts R. Michael , Kaplan Henry J. , Dean Douglas C.
Published: April 2011

Absence of a regenerative pathway for damaged retina following injury or disease has led to experiments using stem cell transplantation for retinal repair, and encouraging results have been obtained in rodents. The swine eye is a closer anatomical and physiological match to the human eye, but embryonic stem cells have not been isolated from pig, and photoreceptor differentiation has not been demonstrated with induced pluripotent stem cells (iPSCs) of swine. Here, we subjected iPSCs of swine to a rod photoreceptor differentiation protocol consisting of floating culture as embryoid bodies followed by differentiation in adherent culture. Real-time PCR and immunostaining of differentiated cells demonstrated loss of expression of the pluripotent genes POU5F1, NANOG, and SOX2 and induction of rod photoreceptor genes RCVRN, NRL, RHO, and ROM1. While these differentiated cells displayed neuronal morphology, culturing on a Matrigel substratum triggered a further morphological change resulting in concentration of rhodopsin (RHO) and rod outer segment-specific membrane protein 1 in outer segment-like projections resembling those on primary cultures of rod photoreceptors. The differentiated cells were transplanted into the subretinal space of pigs treated with iodoacetic acid to eliminate rod photoreceptors. Three weeks after transplantation, engrafted RHO+ cells were evident in the outer nuclear layer where photoreceptors normally reside. A portion of these transplanted cells had generated projections resembling outer segments. These results demonstrate that iPSCs of swine can differentiate into photoreceptors in culture, and these cells can integrate into the damaged swine neural retina, thus, laying a foundation for future studies using the pig as a model for retinal stem cell transplantation.
The domain of international business: Futures and future relevance of international business
Authors: Zettinig Peter , Vincze Zsuzsanna
Published: April 2011

Using data generated by a global Delphi study involving international business (IB) scholars and practitioners, this article reflects on the core and domain of a discipline that, on one side, has to deal with increasing competition from related disciplines, which internationalize their research focus, and, on the other side, is trying to develop conceptual knowledge to explain ever more complex international phenomena. Generating a multilevel framework of important issues for IB leads to propositions, which may widen the focus of the discipline to go beyond the firm, which, comparing IB to related disciplines, can provide pathways that maintain IB highly relevant for most diverse communities affected by international business. ©2011 Wiley Periodicals, Inc.
Materials of large wind turbine blades: recent results in testing and modeling
Authors: Mishnaevsky L. , Brøndsted P. , Nijssen Rogier , Lekou D. J. , Philippidis T. P.
Published: April 2011

The reliability of rotor blades is the pre‐condition for the development and wide use of large wind turbines. In order to accurately predict and improve the wind turbine blade behavior, three main aspects of the reliability and strength of rotor blades were considered: (i) development of methods for the experimental determination of reliable material properties used in the design of wind turbine blades and experimental validation of design models, (ii) development of predictive models for the life prediction, prediction of residual strength and failure probability of the blades and (iii) analysis of the effect of the microstructure of wind turbine blade composites on their strength and ways of microstructural optimization of the materials. By testing reference coupons, the effect of testing parameters (temperature and frequency) on the lifetime of blade composites was investigated, and the input data for advanced design of wind turbine blades were collected. For assessing the residual strength and stiffness of wind turbine blades subjected to irregular cyclic loads, a shell‐based finite element numerical methodology was developed, taking into account the non‐linear response of plies, and experimentally validated. Two methods of structural reliability estimation of the blade, which take into account the stochastic nature of the anisotropic material properties and loads, were developed on the basis of the response surface method and the Edgeworth expansion technique, respectively. The effects of fiber clustering, misalignments, interface properties and other factors on the strength and lifetime of the wind turbine blade materials were investigated in the micromechanical finite element simulations. The results described in this paper stem from the Rotor Structure and Materials task of the UPWIND project. Copyright © 2011 John Wiley & Sons, Ltd.
Student homicidal violence in schools: An international problem
Authors: Bondü Rebecca , Cornell Dewey G. , Scheithauer Herbert
Published: April 2011

School homicides have been become a worldwide phenomenon. In the decade following the Columbine shooting there have been at least forty similar events in other countries. This article addresses the international scope of this problem and some of the complex conceptual issues that make student homicidal violence difficult to define and study. Meaningful research on risk and protective factors that can inform evidence‐based preventive models is summarized.
Cultural and peer influences on homicidal violence: A Finnish perspective
Authors: Kiilakoski Tomi , Oksanen Atte
Published: April 2011

Two case examples of school shootings in Finland illustrate the interplay between the distal, international influence of the Columbine shooting and the more immediate impact of local peer interactions involving both peer bullying at school and peer encouragement of violence through the Internet. Both cases involved emotionally troubled young men who identified with the Columbine attackers and aspired to attain notoriety through similar acts of violence. There was a sequence of missed opportunities for prevention in these shootings that occurred when the student was chronically bullied, developed serious emotional problems, became fascinated with Columbine‐type events, and subsequently began to discuss interests and plans to commit a similar act.
Copper(I) Chelation by Tetradentate NSSN Donor Ligands: Reversible Oxidation but no Oxygenation
Authors: Schnödt Johannes , Sieger Monika , Sarkar Biprajit , Fiedler Jan , Manzur Jorge S. , Su Cheng‐Yong , Kaim Wolfgang
Published: April 2011

The copper(I) complexes [Cu(L4)](ClO4), L4 = 1,6‐bis(N‐methyl‐1H‐benzimidazol‐2‐yl)‐2,5‐dithiahexane (bmbdh) or 1,7‐bis(N‐methyl‐1H‐benzimidazol‐2‐yl)‐2,6‐dithiaheptane (bmdhp) were obtained and investigated through structure analysis (bmdhp compounds), cyclic voltammetry, UV/Vis/NIR and EPR spectroelectrochemistry. Structure comparison of the complexes [Cu(bmdhp)](ClO4) (1) and [Cu(bmdhp)](SO3CF3) (2) with the previously reported [CuI(bdhp)(H2O)](PF6)0.66(BF4)0.34 (4), bdhp = 1,7‐bis(1H‐benzimidazol‐2‐yl)‐2,6‐dithiaheptane, with the related [CuI(mmb)2](BF4) (5), mmb = 1‐methyl‐2‐methylthiomethyl‐1H‐benzimidazole, with the oxidised [CuII(bmdhp)(H2O)](ClO4)2 (7), and with the zinc(II) species [Zn(bmbdh)(H2O)(SO3CF3)](SO3CF3) (8) and {[Zn(μ‐bmdhp)(H2O)(SO3CF3)]2}(SO3CF3) (9) reveal a variety of coordination numbers, L4 ligand coordination modes, M–N bond lengths and especially N–M–N angles, affecting the accessibility of the central metal ions. Electronic consequences as evident from oxidation potentials and from EPR and absorption spectra of the copper(II) forms are discussed. The lack of reactivity of the copper(I) compounds towards O2 is attributed to steric shielding and to electronic effects from two π accepting thioether donors.
Isomorphous Substitution of Iron and Nickel into Analcime Zeolite
Authors: Azizi Seyed Naser , Yousefpour Maryam
Published: April 2011

Studies on the effects of iron and nickel incorporation into the hydrothermal synthesis of ANA zeolite were carried out. The presented work reveals that pure Fe‐Al analcime is synthesized by using starting composition with a higher iron(III) content than reported in previous publications. Furthermore, the iron(III) and nickel(II) contents play important roles in the framework of the synthesized zeolite. XRD, FT‐IR spectroscopy, diffuse reflectance UV/Vis spectroscopy, nitrogen adsorption and SEM were used to characterize the synthesized zeolites. These investigations showed that loading of iron and nickel ions in ANA zeolite changes the pore size and morphology of analcime zeolite.
Epigenetics and the power of art
Authors: Karlic Heidrun , Baurek Pia
Published: April 2011

This review presents an epigenetic view on complex factors leading to development and perception of “genius.” There is increasing evidence which indicates that artistic creativity is influenced by epigenetic processes that act both as targets and mediators of neurotransmitters as well as steroid hormones. Thus, perception and production of art appear to be closely associated with epigenetic contributions to physical and mental health.
Adolescent risk behaviors: Studying typical and atypical individuals via multidimensional scaling profile analysis
Authors: Dong Yang , Ding Cody
Published: April 2011

Within the framework of problem behavior theory, the purpose of this study was to examine risk behavior profiles of typical and atypical adolescents and the differential outcomes of well‐beings for these individuals in the United States. Based on the data from the survey of Health Behavior of School‐Aged Children by World Health Organization, multidimensional scaling profile analysis was used to identify prototypical risk behavior profiles and atypical adolescents. Analyses suggested prototypicality of risk behavior patterns rather than a risk behavior syndrome. The regression analysis was then conducted to investigate the effects of atypical individuals vs. prototypical risk groups on well‐being outcomes. The results indicated that those adolescents who were identified as more atypical than typical reported less positive psychological outcomes.
The Prevalence of Chronic Kidney Disease Requiring Nephrological Referral in Patients with Non-Visible Haematuria
Authors: Taylor Joby , Wilson J. Russell , Chan Koon H. , Urwin Graeme H. , Stower Michael J.
Published: April 2011

Objective:

To quantify the proportion of patients attending for urological investigation of non-visible haematuria who meet criteria for referral to specialist renal services under current UK guidelines.

Patients and methods:

Data were collected from 377 consecutive patients attending a dedicated non-visible haematuria clinic. Details were recorded for clinic outcomes and indicators of chronic kidney disease (eGFR, dipstick proteinuria, protein:creatinine ratio). The proportion of patients meeting referral criteria was calculated, including the increase in service need and costs.

Results:

8.7% of patients had a positive urological diagnosis, with 2.7% having malignancies. 20.7% of patients had CKD stage 3 on the basis of their eGFR readings. 16.7% of patients had dipstick proteinuria, but only 4.4% had a raised protein:creatinine ratio. Overall, up to 22% of patients met current criteria for referral to nephrology, although this varied according to guideline. At this level, it equates to a potential increase of 20–30% in new patient referrals.

Conclusion:

Features of CKD are common in patients undergoing investigation for non-visible haematuria, with high numbers meeting current UK criteria for referral to nephrology. Appropriate investigation of these risk factors should form an integral part of the haematuria clinic.
Ten year course of low back pain in an adult population‐based cohort—The Doetinchem Cohort Study
Authors: van Oostroml Sandra H. , Verschurenl W.M. Monique , de Vetl Henrica C.W. , Picavetl H. Susan J.
Published: April 2011

Background: The long‐term course of long‐standing low back pain is largely unknown since long‐term data are scarce.

Objective: We examined the course of self‐reported low back pain in the prospective population‐based Doetinchem cohort over a period of 10 years.

Methods: Between 1993 and 2007, around 5700 randomly selected men and women in four age groups of originally 20–29, 30–39, 40–49, 50–59 years were measured three times. Logistic regression analysis was used to study the association of sociodemographic (gender, age, education, work status) and lifestyle characteristics (BMI, smoking, physical activity) with persistent and new episodes of long‐standing low back pain.

Results: The prevalence of long‐standing low back pain is quite stable over a 10 year period, approximately 20% on population level. On individual level, around 30% of the population was completely free of low back pain during the entire period, 6% can be characterized as persistent back pain sufferers. Individuals with persistent and a varying pattern have a more unhealthy lifestyle (BMI and smoking) than those without low back pain. Age, smoking, obesity and not having a paid job are associated with 10‐year persistent back pain in the general population, whereas age and not having a paid job are associated in those with long‐lasting back pain at baseline. New episodes of long‐standing back pain are relatively frequent among women and smokers.

Conclusions: Low back pain in the population is characterized as very dynamic which challenges epidemiological studies highly. Long‐term information on the course of back pain is needed to define severe subgroups.
Parent-reported attention-deficit hyperactivity disorder and subtypes of conduct disorder as risk factor of recidivism in detained male adolescents
Authors: Colins O. , Vermeiren R. , Vahl P. , Markus M. , Broekaert E. , Doreleijers T.
Published: April 2011

Objective

Parents are considered to be crucial informants in child psychiatry, particularly for disorders in which age of onset is included in the diagnostic criteria. In detained adolescents, however, parents all too often are difficult to reach or reluctant to cooperate. The clinical relevance of gathering parental information in this context should therefore be demonstrated. This study examines if parent reports of attention-deficit-hyperactivity disorder (ADHD) and age of onset subtypes of conduct disorder (CD) predict official criminal recidivism.

Method

Participants were 110 detained male adolescents from all three Youth Detention Centers in Flanders. Between January 2005 and February 2007, both youth and a parent were interviewed with the Diagnostic Interview Schedule for Children Version IV. Two to 4years later, information on criminal recidivism was retrieved.

Results

Youth self-reported ADHD and CD (subtypes) were not related with recidivism. Parent-reported ADHD, CD and childhood-onset CD predicted serious property recidivism, while parent-reported adolescent-onset CD predicted future violent arrests. In reverse, childhood-onset CD as reported by parents was negatively associated with violent recidivism.

Conclusion

Obtaining parental diagnostic information in delinquent adolescents is crucial for predicting recidivism. This finding emphasizes the need of including parents when studying mental disorder in detained adolescents.
Phosphorylations: making the Neurosporacrassa circadian clock tick
Authors: Diernfellner A.C.R. , Schafmeier T.
Published: April 2011

Various post‐translational modifications have been identified that play a role in the function of circadian clocks. Among these, phosphorylation has been investigated extensively. It was shown that phosphorylation influences half‐life, subcellular localisation, transcriptional activity and conformation of clock components over the course of a circadian day. Recent observations also indicate that time‐of‐day specific sequential phosphorylation of the Neurospora crassa clock protein FREQUENCY is crucial for measuring time and thus for establishing a robust circadian rhythm. The circadian clock of Neurospora is one of the best‐investigated molecular clocks to date. In this review, we summarise the data on what is known so far about the role of phosphorylation of proteins involved in the Neurospora circadian clock.
Pathophysiology of translational regulation by microRNAs in multiple sclerosis
Authors: Junker Andreas
Published: April 2011

This review describes miRNAs regulated in the blood or in brain lesions of MS patients in the context of their previously described functions in physiology and pathophysiology.
A Completely Automated Sample Preparation Instrument and Consumable Device for Isolation and Purification of Nucleic Acids
Authors: Hukari Kyle W. , Shultz Michael , Isely Nikolas , Milson Richard , West Jay A.A.
Published: April 2011

Molecular diagnostic analysis and life science studies are dependent on the ability to effectively prepare samples for analysis. We report the development of a system that enables robust sample preparation of nucleic acids. To enable completely automated sample preparation, a consumable cartridge and consumable module system were developed to emulate every step of the sample preparation process. This included enzyme and reagent addition, temperature-controlled incubations, noncontact mixing of enzymes and reagents, buffer exchanges, and sample elution. Using this system, completely automated methods were developed for the purification of viral RNA and DNA from plasma and whole blood and of bacterial genomic DNA from water and whole blood. Extracted nucleic acids were detected and quantified using real-time PCR. The data indicate that automated viral DNA extraction was more efficient than sample extractions performed using a manual process, whereas automated total RNA extraction from the same samples was equivalent to controls. Additionally, we found that the process for bacterial genomic DNA extraction from either water or whole blood was equivalent to the manual extraction processes. We conclude the instrument, consumable cartridge, and reagent system enables easy, cost-effective, and robust sample preparation regardless of the experience of the operator.
The 104-Well Microplate
Authors: Herrmann Mark G. , Sandrock Tanya M.
Published: April 2011

The 96-well microplate is a ubiquitous tool in the laboratory; its use is so extensive that in a limited number of situations it can be restrictive. Consider the situation where 96 samples need analysis or a downstream process in which the 96-well format leaves no space for additional standards or controls in the upstream 96-well processing. Consequently, plates are split or sample number reduced thereby incurring additional cost for plates, reagents, standards, controls, sample tracking, data files, and time to analyze the entire plate. A simple solution is proposed with the development of a companion 8 times 13-array microplate. The 104-well microplate was developed within the American National Standards Institute/Society for Biomolecular Science standards as to plate geometry and dimension, including well spacing (9 mm) with the exception that the columns have been shifted 4.5 mm to the left to accommodate the 13th column. The extra column allows for additional standards/controls without modifying chemistry, incorporating additional plates or changing to a 384-well plate. We show negligible difference (−0.0003 optical density) when comparing mean absorbance readings in 96- and 104-well format. We demonstrate use of the 104-well plate in a 96-well environment by incorporating it in an enzyme-linked immunosorbent assay on a standard liquid handler. Results from the assay show no difference between formats ( y = 1.039 x − 0.004, r = 0.997). Although the 104 plate was not created to supplant the 96-well standard, we conclude that the 104 plate can be incorporated into the 96-well environment without significant change in existing systems.
Review of the theoretical underpinnings of loyalty programs
Authors: Henderson Conor M. , Beck Joshua T. , Palmatier Robert W.
Published: April 2011

A review of the extant literature reveals that the theoretical underpinnings of the majority of loyalty program research rest on psychological mechanisms from three specific domains—status, habit, and relational. We propose that to understand how loyalty programs actually work, a broader, more holistic research perspective is needed to account for the simultaneous effects across these three theoretical domains as well as both cross‐customer and temporal effects. The contribution of this approach is a fresh research agenda advanced in 15 research propositions.
MRI findings, surgical treatment and follow-up of a myelomeningocele with tethered spinal cord syndrome in a cat
Authors: Ricci Emanuele , Cherubini Giunio B. , Jakovljevic Samuel , Aprea Francesco , Cantile Carlo
Published: April 2011

A 7-month-old male neutered cat was referred for paraparesis and painful sensation at the level of T13 vertebra where a dermal cyst was observed. Spine radiographs and magnetic resonance imaging (MRI) showed a well-encapsulated cyst communicating with the meninges and spinal cord, suggestive of hydromyelia and myelodysplasia. Dorsal laminectomy was performed and the cyst was completely removed. The day after surgery, the cat was ambulatory paraparetic. Involuntary defecation was observed for only a few days. The surgical specimen was cystic and covered by skin. Microscopic examination revealed a hollow hemispheric mass of glial fibrillary acidic protein (GFAP)-positive neural tissue lined by ependyma and formed of glia and vascular structures consistent with myelomeningocele (MMC). Only anecdotal descriptions of MMC have been published in the veterinary literature, mainly in the lumbosacral spinal cord. To the authors’ knowledge, this is the first report of a MMC with tethered spinal cord syndrome in a cat successfully treated surgically.
Reduction of feral cat (Felis catus Linnaeus 1758) colony size following hysterectomy of adult female cats
Authors: Mendes-de-Almeida Flavya , Remy Gabriella L. , Gershony Liza C. , Rodrigues Daniela P. , Chame Marcia , Labarthe Norma V.
Published: April 2011

The size of urban cat colonies is limited only by the availability of food and shelter; therefore, their population growth challenges all known population control programs. To test a new population control method, a free-roaming feral cat colony at the Zoological Park in the city of Rio de Janeiro was studied, beginning in 2001. The novel method consisted of performing a hysterectomy on all captured female cats over 6 months of age. To estimate the size of the colony and compare population from year to year, a method of capture-mark-release-recapture was used. The aim was to capture as many individuals as possible, including cats of all ages and gender to estimate numbers of cats in all population categories. Results indicated that the feral cat population remained constant from 2001 to 2004. From 2004 to 2008, the hysterectomy program and population estimates were performed every other year (2006 and 2008). The population was estimated to be 40 cats in 2004, 26 in 2006, and 17 cats in 2008. Although pathogens tend to infect more individuals as the population grows older and maintains natural behavior, these results show that free-roaming feral cat colonies could have their population controlled by a biannual program that focuses on hysterectomy of sexually active female cats.