bluuebunny/crossref_metadata_2025 huggingface dataset:
Is suboptimal prescribing a risk factor for poor health outcomes in community‐dwelling elders? The ICARe Dicomano study
Authors: Pozzi C. , Lapi F. , Mazzaglia G. , Inzitari M. , Boncinelli M. , Geppetti P. , Mugelli A. , Marchionni N. , Di Bari M.
Published: July 2010

Purpose

Mostly because of comorbidity and drugs consumption, older persons are often exposed to an increased risk of sub‐optimal prescribing (SP). At present, few studies investigated the association between SP and long‐term health outcomes. We examined the relation between SP and the risk of mortality and hospitalization in Italian older community‐dwellers.

Methods

Older (65+ years) community‐dwelling residents of a small town in Tuscany were enrolled in a longitudinal study. SP was defined as polypharmacy (use of 5+ drugs), prescription of inappropriate drugs (ID) according to Beers' criteria, and of potentially interacting drugs (PID), evaluated in 1995 and 1999. These three forms of SP were entered as time‐dependent exposures into multivariable Cox regression analysis models, whose outcomes were mortality and hospitalizations through 2003.

Results

Of 1022 participants (mean age 73.0 ± 6.8, 57% women), 220 were evaluated in 1995, 234 in 1999 and 568 in both waves. In univariate analysis, mortality was two‐fold higher in participants with polypharmacy (73.4/1000 person/years, 95% CI 58.2–92.4 vs. 34.1, 95% CI 29.7–39.2; p < 0.001) or PID (72.7/1000 person/years, 95% CI 46.3–113.9 vs. 38.0, 95% CI 33.5–43.1; p < 0.001), whereas it was unrelated to the presence of ID. Hospitalization rates were independent of any form of SP. In multivariable models, polypharmacy, ID, and PID were no longer associated with an increased risk of death, and ID predicted a slightly increased risk of hospitalizations (HR 1.03, 95% CI 1.0–1.06, p = 0.048).

Conclusions

In this cohort, SP was not associated with an excess risk of poor health outcomes. Copyright © 2010 John Wiley & Sons, Ltd.
p53 downregulates the gene expression of mitochondrial aconitase in human prostate carcinoma cells
Authors: Tsui Ke‐Hung , Feng Tsui‐Hsia , Lin Yu‐Fen , Chang Phei‐Lang , Juang Horng‐Heng
Published: July 2010

BACKGROUND

Mitochondrial aconitase (mACON) is regarded as the key enzyme in citrate oxidation in human prostate epithelial cells, and its abnormal expression has been implicated in tumorigenesis of the prostate. Evidence also supports a broad role for the p53 gene in suppressing prostatic tumorigenesis. We investigated whether p53 regulates mACON expression and explore the potential mechanisms responsible for its effect on prostate cancer cells.

METHODS

Camptothecin (CPT) treatments and transient overexpression of p53 were used to investigate p53 regulation of mACON and may effects were assessed using immunoblotting and transient gene expression assays.

RESULTS

In vitro enzymatic activity assays and immunoblot assays showed that CPT treatment induced p53 expression while reducing mACON protein biosynthesis in wild‐type p53 expressing LNCaP cells. Immunoblot assays and reporter assays revealed that transient transfection of a p53 expression vector into p53‐null PC‐3 cells decreased mACON expression. Cyclic pifithrin‐α, an inhibitor of p53 transcriptional activity, blocked the decrease in mACON gene expression resulting from CPT treatment in LNCaP cells. Two putative p53 response elements were identified within the mACON promoter; however, mutation of these putative p53 response elements did not abolish the effect of CPT whereby it decreased mACON expression. A similar result was obtained for the effect of these mutants on the promoter activity of the mACON gene after transient overexpression of p53.

CONCLUSIONS

Together these results suggest that p53 downregulation of mACON gene expression in human prostate carcinoma cells may not occur through the putative consensus p53 response elements found within the mACON promoter. Prostate 71: 62–70, 2011. © 2010 Wiley‐Liss, Inc.
Dissection of the conformational cycle of the multidrug/lipidA ABC exporter MsbA
Authors: Doshi Rupak , Woebking Barbara , van Veen Hendrik W.
Published: July 2010

Recent crystal structures of the multidrug ATP‐binding cassette (ABC) exporters Sav1866 from Staphylococcus aureus, MsbA from Escherichia coli, Vibrio cholera, and Salmonella typhimurium, and mouse ABCB1a suggest a common alternating access mechanism for export. However, the molecular framework underlying this mechanism is critically dependent on assumed conformational relationships between nonidentical crystal structures and therefore requires biochemical verification. The structures of homodimeric MsbA reveal a pair of glutamate residues (E208 and E208′) in the intracellular domains of its two half‐transporters, close to the nucleotide‐binding domains (NBDs), which are in close proximity of each other in the outward‐facing state but not in the inward‐facing state. Using intermolecular cysteine crosslinking between E208C and E208C′ in E. coli MsbA, we demonstrate that the NBDs dissociate in nucleotide‐free conditions and come close on ATP binding and ADP·vanadate trapping. Interestingly, ADP alone separates the half‐transporters like a nucleotide‐free state, presumably for the following catalytic cycle. Our data fill persistent gaps in current studies on the conformational dynamics of a variety of ABC exporters. Based on a single biochemical method, the findings describe a conformational cycle for a single ABC exporter at major checkpoints of the ATPase reaction under experimental conditions, where the exporter is transport active. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Solution conformation of a tetradecapeptide stabilized by two di‐n‐propyl glycine residues
Authors: Sarojini Vijayalekshmi , Balaji Rao R. , Ragothama S. , Balaram Padmanabhan
Published: July 2010

The solution conformation of a designed tetradecapeptide Boc‐Val‐Ala‐Leu‐Dpg‐Val‐Ala‐Leu‐Val‐Ala‐Leu‐Dpg‐Val‐Ala‐Leu‐OMe (Dpg‐14) containing two di‐n‐propyl glycine (Dpg) residues has been investigated by 1H NMR and circular dichroism in organic solvents. The peptide aggregates formed at a concentration of 3 mM in the apolar solvent CDCl3 were broken by the addition of 12% v/v of the more polar solvent DMSO‐d6. Successive NiH $\leftrightarrow$ Ni+1H NOEs observed over the entire length of the sequence in this solvent mixture together with the observation of several characteristic medium‐range NOEs support a major population of continuous helical conformations for Dpg‐14. Majority of the observed coupling constants ($^{3}_{\rm {JNHC}}{^{\alpha}}_{\rm {H}}$) also support ϕ values in the helical conformation. Circular dichroism spectra recorded in methanol and propan‐2‐ol give further support in favor of helical conformation for Dpg‐14 and the stability of the helix at higher temperature. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Epimerization‐free synthesis of cyclic peptide by use of the O‐acyl isopeptide method
Authors: Yoshiya Taku , Kawashima Hiroyuki , Hasegawa Yuka , Okamoto Kazuhiro , Kimura Tooru , Sohma Youhei , Kiso Yoshiaki
Published: July 2010

A head‐to‐tail cyclization of a protected linear hexapeptide with a C‐terminal O‐acyl isopeptide proceeded to give a cyclic O‐acyl isopeptide without epimerization. The cyclic O‐acyl isopeptide possessed different secondary structures compared with the native cyclic peptide. The isopeptide was then efficiently converted to the desired cyclic peptide via an O‐to‐N acyl migration reaction using a silica gel‐anchored base. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Growth and structural characterization of pyramidal site‐controlled quantum dots with high uniformity and spectral purity
Authors: Dimastrodonato Valeria , Mereni Lorenzo O. , Young Robert J. , Pelucchi Emanuele
Published: July 2010

This work presents some fundamental features of pyramidal site‐controlled InGaAs Quantum Dots (QDs) grown by metal–organic vapour phase epitaxy on patterned GaAs (111)B substrate. The dots self‐form inside pyramidal recesses patterned on the wafer via pre‐growth processing. The major advantage of this growth technique is the control it provides over the dot nucleation position and the dimensions of the confined structures onto the substrate. The fundamental steps of substrate patterning and the QD formation mechanism are described together with a discussion of the structural particulars. The post‐growth processes, including surface etching and substrate removal, which are required to facilitate optical characterization, are discussed. With this approach extremely high uniformity and record spectral purity are both achieved.
Fast construction of the Kohn–Sham response function for molecules
Authors: Koval Peter , Foerster Dietrich , Coulaud Olivier
Published: July 2010

The use of the linear combination of atomic orbitals method for excited states involves products of orbitals that are known to be linearly dependent. We identify a basis in the space of orbital products that is local for orbitals of finite support and with a residual error that vanishes exponentially with its dimension. As an application of our previously reported technique we compute the Kohn–Sham density response function $\chi _{0} $ for a molecule consisting of N atoms in $N^{2} N_{\omega } $ operations, with $N_{\omega } $ the number of frequency points. We test our construction of $\chi _{0} $ by computing molecular spectra directly from the equations of Petersilka–Gossmann–Gross in $N^{2} N_{\omega } $ operations rather than from Casida's equations which takes $N^{3} $ operations. We consider the good agreement with previously calculated molecular spectra as a validation of our construction of $\chi _{0} $. Ongoing work indicates that our method is well suited for the computation of the GW self‐energy $\Sigma = {\rm i}GW$ and we expect it to be useful in the analysis of exitonic effects in molecules.
Magnetic properties of a cylindrical Ising nanowire (or nanotube)
Authors: Kaneyoshi T.
Published: July 2010

Magnetic properties (phase diagram and magnetization) of a cylindrical Ising nanowire or nanotube are investigated by the use of the effective‐field theory with correlations. Particular emphasis is given to the effects of the surface and its dilution on them. Much attention is paid to the thermal variation of the magnetization when the spins at the surface are coupled antiferromagnetically to the ferromagnetic core spins by the negative shell coupling. The effects of dilution at the surface, the surface exchange interaction, and the shell coupling on the magnetization profiles are investigated. We find a number of characteristic phenomena for them.
Elastic properties of superconducting MAX phases from first‐principles calculations
Authors: Shein Igor R. , Ivanovskii Alexander L.
Published: July 2010

Using first‐principles density functional calculations, a systematic study of the elastic properties for all known superconducting MAX phases (Nb2SC, Nb2SnC, Nb2AsC, Nb2InC, Mo2GaC, and Ti2InC) was performed. As a result, the optimized lattice parameters, independent elastic constants, indicators of elastic anisotropy, and brittle/ductile behavior as well as the so‐called machinability indexes were calculated. We also derived bulk and shear moduli, Young's moduli, and Poisson's ratios for ideal polycrystalline MAX aggregates. The results obtained are discussed in comparison with available theoretical and experimental data and elastic parameters for other layered superconductors.
First principles theoretical study of complex magnetic order in transition‐metal nanowires
Authors: Saubanère M. , Tanveer M. , Ruiz‐Díaz P. , Pastor G. M.
Published: July 2010

The electronic and magnetic properties of one‐dimensional (1D) transition‐metal (TM) systems are investigated from a first principles theoretical perspective. The development of local magnetic moments and the stability of various collinear and non‐collinear spin arrangements are determined in the framework of a generalized gradient approximation to density‐functional theory (DFT). Two specific complementary problems are considered. The first one concerns the local moment formation in Cu wires doped with Co and Ni impurities. Recent results as a function of wire length, interatomic distances, impurity position within the wire, and total spin polarization$S_{z} $are reviewed. It is shown that both Co and Ni impurities preserve their magnetic degree of freedom in monoatomic Cu wires by developing almost saturated local moments in all low‐lying total spin configurations ($S_{z} \leq 5/2$). The impurity moments are largely dominated by the d‐electron contributions. In the ground state they couple ferromagnetically with the moments induced at the Cu host atoms. The changes in the spin‐density distribution and in the local densities of electronic states are quantified as a function of the position of the impurity position within the wire. In addition, recent results on the ground‐state magnetic order in V nanowires are reviewed. The stability of ferromagnetic (FM), antiferromagnetic (AF), and spiral non‐collinear (NC) orders is analyzed in terms of the frozen‐magnon spectrum. A remarkable transition from FM to NC order is observed as a function of the nearest‐neighbor (NN) distancea. The dependence of the single‐particle electronic structure of the wire on the wave‐vector of the spin‐density wave (SDW) is demonstrated. Finally, the role of magnetic anisotropy on the stability of NC order is discussed in the framework of a simple classical spin model.
Effects of strain‐control layers on piezoelectric field and indium incorporation in InGaN/GaN blue quantum wells
Authors: Song Jae‐Ho , Dong Yanqun , Kim Ho‐Jong , Ahn Byung‐Jun , Kim Tae‐Soo , Hong Soon‐Ku , Yuh Hwan‐Kuk , Choi Sung‐Chul , Moon Youngboo , Shee Sangkee , Lee Jae‐Hak , Song Jung‐Hoon
Published: July 2010

We investigated the effects of a strain‐control layer on piezoelectric fields and indium incorporation in blue‐emitting InGaN/GaN quantum wells (QWs) using reverse‐biased electroreflectance spectroscopy. With this technique, we could determine the change in both indium incorporation and the piezoelectric field by the inserted buffer layer. We compared two test samples, which have identical structures except for the insertion of an additional InGaN layer at the bottom of the blue‐QW. The magnitude of the piezoelectric fields in the QWs with the added layer was significantly smaller even with a slightly higher indium composition. The result shows that the strain in the QW is partially released and can be controlled quantitatively by the strain‐control layer underneath. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ge/Si(100) quantum dots grown via a thin Sb layer
Authors: Tonkikh Alexander , Zakharov Nikolay , Talalaev Vadim , Werner Peter
Published: July 2010

We report on a way to grow very small Ge islands (basis about 15 nm, height about 1 nm, density 2 × 1011 cm–2) on a Si substrate by molecular beam epitaxy. By the deposition of lowest amounts of antimony prior to the Ge deposition we could influence the formation kinetics of Ge islands. After the covering of the islands by a Si layer the samples show pronounced photoluminescence at room temperature in the range of 1.5 μm. The results of the optical spectroscopy experiments are interpreted in this way that these Ge nanoislands show a quantum confinement, and therefore, they can be regarded as quantum dots.

magnified image

AFM and TEM micrographs, and room temperature PL spectrum of Sb assisted Ge/Si(100) QDs.

(© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Highly confined surface plasmon polariton resonances in rectangular nanopore cavities
Authors: Chen Chang , Lagae Liesbet , Maes Guido , Borghs Gustaaf , Van Dorpe Pol
Published: July 2010

The excitation of surface plasmons in nanoslits in metal films is known to result in large electromagnetic field enhancements. The enhancement factor strongly depends on the exact geometrical parameters, such as widths and lengths. In this work, we numerically study field enhancement and transmission resonances inside short nanoslits (nanopores) with varying lengths using three‐dimensional finite difference time domain (FDTD) simulations. The results indicate that the excitation of highly confined lateral Fabry–Pérot surface plasmon resonances results in enhancement factors greatly exceeding the two‐dimensional case. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical study of the structural and electronic properties of aggregates, wires, and bulk phases formed from M@Si16 superatoms (M = Sc−, Ti, V+)
Authors: Torres M. B. , Fernández E. M. , Balbás L. C.
Published: July 2010

Starting with the nearly spherical endohedral M@Si16 cage‐like clusters (M = Sc−, Ti, V+) in their fullerene‐like isomerical form with D4d symmetry, we study the trends in the formation of [Ti@Si16]n, [Sc@Si16K]n, and [V@Si16F]n aggregates as their size increase (n ≤ 9). We identify specially stable linear, planar, and three‐dimensional patterns, which can serve to grow low‐dimensional infinite systems. The structure and cohesive energy of a few infinite chains of that type are optimized. We also present calculations of fcc, bcc, and single cubic crystal meta stable phases having the Ti@Si16 superatom as basic unit, as well as cubic NaCl and CsCl bulk structures of Sc@Si16K and V@Si16F supermolecules. The orientation and isomerization of the superatom or supermolecule in the cubic cell plays an important role. The projected density of states of V@Si16F crystal with NaCl structure shows a meta stable ferromagnetic phase due to polarization of d electrons of vanadium. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
A new perspective on implementation by voting trees
Authors: Fischer Felix , Procaccia Ariel D. , Samorodnitsky Alex
Published: July 2010

Voting trees describe an iterative procedure for selecting a single vertex from a tournament. They provide a very general abstract model of decision‐making among a group of individuals, and it has therefore been studied which voting rules have a tree that implements them, i.e., chooses according to the rule for every tournament. While partial results concerning implementable rules and necessary conditions for implementability have been obtained over the past 40 years, a complete characterization of voting rules implementable by trees has proven surprisingly hard to find. A prominent rule that cannot be implemented by trees is the Copeland rule, which singles out vertices with maximum degree.

In this paper, we suggest a new angle of attack and re‐examine the implementability of the Copeland solution using paradigms and techniques that are at the core of theoretical computer science. We study the extent to which voting trees can approximate the maximum degree in a tournament, and give upper and lower bounds on the worst‐case ratio between the degree of the vertex chosen by a tree and the maximum degree, both for the deterministic model concerned with a single fixed tree, and for randomizations over arbitrary sets of trees. Our main positive result is a randomization over surjective trees of polynomial size that provides an approximation ratio of at least 1/2. The proof is based on a connection between a randomization over caterpillar trees and a rapidly mixing Markov chain. © 2010 Wiley Periodicals, Inc. Random Struct. Alg., 39, 59–82, 2011
Lecturing to 200 students and its effects on cytokine concentration and salivary markers of adrenal activation
Authors: Filaire Edith , Larue Jacques , Portier Hugues , Abed Aicha , Graziella Pavon‐Djavid , Teixeira Anna , Anne Pelle
Published: July 2010

Stress not only activates the SAM system and the hypothalamic–pituitary–adrenal axes, but also the immune system. The aims of this study are to assess the physiological variations in saliva (cytokines, cortisol and alpha‐amylase) and perceived stress in professors when they had to lecture to 200 students. A total of eight unstimulated saliva samples were collected from nine professors: four on a working day that included the lecture and four controls on a working day without a lecture. The professors also rated subjective stress on a seven‐point scale 5 min before the lecture, immediately after the lecture and at the same times on the control day. The lecture elicited substantial increases in subjective stress ratings, with the values on the lecture day significantly higher than those on the control day. Lecturing resulted in significant increases in Tumor Necrosis Factor (TNF)‐α, Interleukin (IL)‐2 and IL‐4 concentrations, but did not affect the IL‐10 values. These changes appeared to be concomitant with changes in the concentrations of the stress markers, alpha‐amylase and cortisol. The mechanisms by which psychosocial stress can induce cytokine changes and modify the activity of salivary alpha‐amylase are not entirely understood, and further research is thus warranted. Copyright © 2010 John Wiley & Sons, Ltd.
Patient and nurse perceptions of stressors in the intensive care unit
Authors: Yava Ayla , Tosun Nuran , Ünver Vesile , Çiçek Hatice
Published: July 2010

The objective of the study was to determine the perceptions of a group of patients on intensive care units' (ICUs) stressors and the perceptions of nurses on ICU patients' stressors in Turkey, and compare the differences in patients' and nurses' perception of the stressors in ICUs. In this descriptive study, 155 patients who were admitted to medical or surgical ICUs and 152 nurses who are employed in the same units of two training and research hospitals in Turkey were enrolled in this study. The ICU Environmental Stressor Scale (ICUESS) was used to determine intensive care stressors. According to total ICUESS mean scores, patients (91.41 ± 34.91) perceived significantly less stress than the ICU nurses (133.23 ± 32.20) perceived them to have. Both patients and nurses ranked ‘fear of death’ as the greatest stressor. Physiological stressors were identified as the most important stressors by both patients and nurses. Patients and nurses in medical ICUs were more affected by stressors than their counterparts in surgical ICUs. Patients with unplanned or emergency admissions perceived higher stress than that of patients with planned admissions. Several factors could help reduce these stressors, such as having familiar arrangements, humane ICU environment, individual patient assessments and appropriate nursing interventions. Copyright © 2010 John Wiley & Sons, Ltd.
Writing, Self‐Healing, and Self‐Erasing on Conductive Pressure‐Sensitive Adhesives
Authors: Alessandri Ivano
Published: July 2010

A simple strategy for enabling conductive pressure sensitive adhesives (PSAs) to work as light‐responsive materials is reported. Direct laser‐writing of PSA substrates was achieved by means of a continuous‐wave He‐Ne laser focused through the objectives of an optical microscope. This approach takes advantage of cooperative interplay between viscoelastic properties of PSAs and enhanced thermal conductivity provided by an extra overlayer of gold. In particular, the thickness of the gold layer is a crucial parameter for tuning the substrate responsiveness. Self‐healing and self‐degradation processes can be exploited for controlling the lifetime of the written information, whereas additional protective coatings can be introduced to achieve permanent storage.
A theory of knowledge construction systems
Authors: Nakamori Yoshiteru , Wierzbicki Andrzej P. , Zhu Zhichang
Published: July 2010

This paper considers the problem of knowledge integration, and proposes a theory of knowledge construction systems, which consists of three fundamental parts: a knowledge construction system, a structure–agency–action paradigm, and evolutionary‐constructive objectivism. The first part is a model of collecting and synthesizing knowledge, the second relates to necessary abilities of actors when collecting knowledge in individual domains, and the third comprises a set of principles to justify collected and synthesized knowledge. The paper starts with a brief introduction of our basic systems approach, called ‘informed systems thinking’, followed by a summary of our proposal: a theory of knowledge construction systems. The paper then explains its three fundamental parts, with a special emphasis on the types of knowledge integration, and finally gives a detailed explanation of the theory with an example. Copyright © 2010 John Wiley & Sons, Ltd.
The molecular structures of starch components and their contribution to the architecture of starch granules: A comprehensive review
Authors: Pérez Serge , Bertoft Eric
Published: July 2010

Recent developments in methods and instrumentation have contributed to major advances in our understanding of the fine structure of amylose and amylopectin. The structure of the starch granule slowly unravels with new insight into key structural features. Following a brief presentation of the structural features common to all starches, the most recent findings for the structure of amylose and amylopectin are reported. The organization of different types of chains in amylopectin is discussed with a critical review of the ‘cluster’ model leading to the presentation of alternative models. The locations of molecular components in the starch granule are described according to a progress structural order. The description of the crystalline components is followed by a presentation of their supramolecular arrangements. The crystalline components comprise platelet nanocrystals which have already been identified and characterized, and other less well characterized ‘blocklet components’. The location and state of amylose within the granule is also presented. This comprehensive review aims at distinguishing between those structural features that have received widespread acceptance and those that are still under debate, with the ambition of being educational and to provide stimulation for further fundamental investigation into the starch granule as a macromolecular assembly.
Oxidative stress induced by 2,4‐phenoxyacetic acid in liver of female rats and their progeny: Biochemical and histopathological studies
Authors: Troudi Afef , Ben Amara Ibtissem , Samet Amira Mahjoubi , Zeghal Najiba
Published: July 2010

The 2,4‐Dichlorophenoxyacetic acid (2,4‐D) was used in agriculture as an herbicide in many countries including Tunisia. The aim of this study was to evaluate the effects of 2,4‐D on liver function of adult rats and their progeny. Female Wistar rats were divided into two groups: the controls and the treated rats which received 600 ppm of 2,4‐D in their drinking water from the 14th day of pregnancy until day 14 after delivery. In 2,4‐D group, a significant decrease in body weight of pups was noted, when compared to controls. Liver antioxidant enzyme activities, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) decreased, while malondialdehyde (MDA) levels increased in dams and pups. Moreover, plasma aminotransferases (ALT, AST), gamma glutamil transpeptidase (GGT), lactate dehydrogenase (LDH), bilirubin and albumin levels were increased significantly. The biochemical modifications were correlated with histopathological studies. We concluded that 2,4‐D induced hepatotoxicity in adult and suckling rats. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
Induction of reactive oxygen species and algal growth inhibition by tritiated water with or without copper
Authors: Réty C. , Gilbin R. , Gomez E.
Published: July 2010

Tritium (3H) is a radioactive element of ecological concern because of its release into aquatic ecosystems from nuclear power plants. However, the acute and chronic effects of tritiated water (HTO) on aquatic organisms are poorly documented, as are its effects on oxidative stress. In addition, the effects of HTO in combination with other contaminants remain largely unexamined. Herein, we document the effect of HTO on a primary aquatic producer (Chlamydomonas reinhardtii) by measuring growth and oxidative stress using fluorimetric (H2DCF‐DA) determination of Reactive Oxygen Species (ROS) production. The maximum cell density of the alga (1.65 × 106cells mL‐1) was reduced by 23% (1.27 × 106cells mL‐1) at the highest exposure tested (59 MBq mL‐1HTO), whereas cells exposed to 0.9 MBq mL‐1showed a significantly enhanced maximum cell density of 1.90 × 106cells mL‐1, an increase of 15%. With regard to oxidative stress, exposure to HTO (0.04, 0.16, and 2.8 MBq mL‐1) induced an early dose‐dependent peak in ROS production after 14–15 min of exposure, followed by a slow decrease in ROS which stabilized after 60 min. Moreover, this study showed that the presence of HTO may influence the impact of other conventional, nonradioactive contaminants, such as copper, a well known oxidizing trace metal for aquatic organisms. A significant synergic effect of copper and HTO on ROS production was observed. This synergic effect on oxidative stress was shown to be linked to an enhanced copper uptake rate measured in the presence of HTO (> 4 times). We conclude that HTO should be considered as a sensitizer when in a mixture with other contaminants, especially through interactions on the antioxidant system of algae. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
Embryotoxic and teratogenic effects of pesticides in chick embryos: A comparative study using two commercial formulations
Authors: Uggini Gowri K. , Patel Prabhudas V. , Balakrishnan Suresh
Published: July 2010

Developmental toxicity of two different classes of commercial formulations of insecticides was studied by in ovo treatment of fertilized Rhode Island Red eggs. The first one was a combination of chlorpyrifos and cypermethrin and the second one was spinosad, a fermentation product of soil bacterium, Actinomycetes. In this study, the combination pesticide and spinosad of different concentrations were administered as a single dose in ovo in volumes of 50 μL per each egg on day “0” of incubation. Embryonic growth and development, morphological and skeletal malformations, and hatchability were assessed. The combination insecticide induced explicit alterations in the embryonic growth and development and resulted in malformations particularly to the axial and appendicular skeletal structures, whereas the changes were trivial in case of the spinosad exposure. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
Acetyl cholinesterase activity and muscle contraction in the sea urchin Lytechinus variegatus (Lamarck) following chronic phosphate exposure
Authors: Boettger S. Anne , McClintock James B.
Published: July 2010

The common shallow‐water sea urchin Lytechinus variegatus is capable of surviving inorganic phosphate exposures as high as 3.2 mg L−1 and organic phosphate exposures of 1000 mg L−1. Nonetheless, chronic exposure to low, medium, and high‐sublethal concentrations of organic phosphate inhibits the muscle enzyme acetyl cholinesterase (AChE), responsible for the break down of the neurotransmitter acetylcholine, as well as inhibiting contractions in the muscles associated with the Aristotle's lantern. AChE activity, measured in both a static enzyme assay and by vesicular staining, displayed concentration‐dependent declines of activity in individuals maintained in organic phosphate for 4 weeks. The activity of AChE was not adversely affected by exposure to inorganic phosphate or seawater controls over the same time period. Maximum force of muscle contraction and rates of muscle contraction and relaxation also decreased with chronic exposure to increasing concentrations of organic phosphate. Chronic exposure to inorganic phosphates elicited no response except at the highest concentration, where the maximum force of muscular contraction increased compared to controls. These findings indicate that shallow‐water populations of Lytechinus variegatus subjected to organic phosphate pollutants may display impaired muscular activity that is potentially related to the inhibition of the muscle relaxant enzyme AChE, and subsequently muscular overstimulation, and fatigue. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
A cross‐layer approach for integrating security mechanisms in sensor networks architectures
Authors: Roman Rodrigo , Lopez Javier , Najera Pablo
Published: July 2010

The wireless sensor networks (WSN) paradigm is especially vulnerable against external and internal attacks. Therefore, it is necessary to develop security mechanisms and protocols to protect them. These mechanisms must become an integral part of the software architecture and network stack of a sensor node. A question that remains is how to achieve this integration. In this paper we check how both academic and industrial solutions tackle this issue, and we present the concept of a transversal layer, where all the different security mechanisms could be contained. This way, all the elements of the architecture can interact with the security mechanisms, and the security mechanisms can have a holistic point of view of the whole architecture. We discuss the advantages of this approach, and also present how the transversal layer concept was applied to a real middleware architecture. Copyright © 2010 John Wiley & Sons, Ltd.
A security framework for wireless mesh networks
Authors: Mogre Parag S. , Graffi Kalman , Hollick Matthias , Steinmetz Ralf
Published: July 2010

The class of Wireless Mesh Networks (WMN) supports an ample set of applications including wireless community networks, radio access networks in rural or metropolitan areas, or wireless backbones for factory/process automation. Guaranteeing security is crucial for within these application scenarios. While contemporary wireless technologies, such as the IEEE 802.16 or the IEEE 802.11s standard, provide the basic protocol mechanisms for mesh networking, they lack in comprehensive security mechanisms. Additionally, novel security features of the above standards such as per‐link encryption break existing security solutions that rely on overhearing of the wireless channel. We close this gap by developing a holistic approach toward securing WMNs with particular focus on the network layer. We perform a threat analysis and then develop solutions (1) guaranteeing the integrity and authenticity of routing messages, (2) to locally and globally detect misbehavior of nodes in forwarding data or routing messages even for settings that do not allow for overhearing the channel, and (3) to dynamically manage reputation of nodes throughout the network. The combination of these building blocks enables to provide for secure, self‐organizing WMNs. As a proof‐of‐concept, we tailor and implement our solutions for the setting of a realistic IEEE 802.16 mesh network; we discuss the protection achieved and assess selected performance trade‐offs for the developed mechanisms. Copyright © 2010 John Wiley & Sons, Ltd.
Pretense and imagination
Authors: Liao Shen‐yi , Szabó Gendler Tamar
Published: July 2010

Issues of pretense and imagination are of central interest to philosophers, psychologists, and researchers in allied fields. In this entry, we provide a roadmap of some of the central themes around which discussion has been focused. We begin with an overview of pretense, imagination, and the relationship between them. We then shift our attention to the four specific topics where the disciplines' research programs have intersected or where additional interactions could prove mutually beneficial: the psychological underpinnings of performing pretense and of recognizing pretense, the cognitive capacities involved in imaginative engagement with fictions, and the real‐world impact of make‐believe. In the final section, we discuss more briefly a number of other mental activities that arguably involve imagining, including counterfactual reasoning, delusions, and dreaming.WIREs Cogn Sci2011 2 79–94 DOI: 10.1002/wcs.91

This article is categorized under:

Psychology > Development and Aging

Philosophy > Foundations of Cognitive Science
Tissue scaffolds for skin wound healing and dermal reconstruction
Authors: Zhong S. P. , Zhang Y. Z. , Lim C. T.
Published: July 2010

One of the major applications of tissue‐engineered skin substitutes for wound healing is to promote the healing of cutaneous wounds. In this respect, many important clinical milestones have been reached in the past decades. However, currently available skin substitutes for wound healing often suffer from a range of problems including wound contraction, scar formation, and poor integration with host tissue. Engineering skin substitutes by tissue engineering approach has relied upon the creation of three‐dimensional scaffolds as extracellular matrix (ECM) analog to guide cell adhesion, growth, and differentiation to form skin‐functional and structural tissue. The three‐dimensional scaffolds can not only cover wound and give a physical barrier against external infection as wound dressing, but also can provide support both for dermal fibroblasts and the overlying keratinocytes for skin tissue engineering. A successful tissue scaffold should exhibit appropriate physical and mechanical characteristics and provide an appropriate surface chemistry and nano and microstructures to facilitate cellular attachment, proliferation, and differentiation. A variety of scaffolds have been fabricated based on materials ranging from naturally occurring ones to those manufactured synthetically. This review discusses a variety of commercial or laboratory‐engineered skin substitutes for wound healing. Central to the discussion are the scaffolds/materials, fabrication techniques, and their characteristics associated with wound healing. One specifically highlighted emerging fabrication technique is electrospinning that allows the design and fabrication of biomimetic scaffolds that offer tremendous potential applications in wound healing of skin. WIREs Nanomed Nanobiotechnol 2010 2 510–525

This article is categorized under:

Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement
Synthese von 3‐DBU‐closo‐2‐CB6H6 und [3‐Cl‐closo‐2‐CB6H6]– – eine erste einfache Synthese für [CB6]‐closo‐Cluster
Authors: Schlüter Florian , Bernhardt Eduard
Published: July 2010

The closo‐hydro‐borate [B6H6]2– reacts with DBU (= 1,8‐Diazabicyclo[5.4.0]undec‐7‐en) in chloroform to give a mixture of two different seven‐vertex monocarboranes, 3‐DBU‐closo‐2‐CB6H6 and [3‐Cl‐closo‐2‐CB6H6]–. Dichlorocarbene, which is generated in situ by the reaction of DBU with chloroform at elevated temperatures, subsequently inserts into the [B6H6]‐closo‐cluster to result in 3‐DBU‐closo‐2‐CB6H6 as main product [3‐Cl‐closo‐2‐CB6H6]– was obtained as a byproduct. Both novel carboranes were isolated and characterized by 1H, 1H{11B}, 11B, 11B{1H} and 13C NMR spectroscopy. The structures of 3‐DBU‐closo‐2‐CB6H6 as well as [3‐Cl‐closo‐2‐CB6H6]– were determined by single‐crystal X‐ray diffraction.
Dynamic Expansion of a Spherical Cavity in an Unbounded Hyperelastic Medium
Authors: Mioduchowski A. , Haddow J. B.
Published: July 2010

An approximate method, based on a discrete model, is given for the solution of certain spherically symmetric dynamic finite deformation problems of an unbounded compressible hyperelastic medium. The method is outlined for expansion of a spherical cavity and results are presented for a particular strain energy function.
A Misfit and a Crack in an Infinite Elastic Plate
Authors: Bhargava R. D. , Bhargava R. R.
Published: July 2010

In this paper, the following problem is investigated. Consider an infinite, isotropic elastic plate with a circular cavity and a straight crack. A circular disc of dimension slightly larger than that of the circular cavity is inserted into the cavity and welded round it to prevent sliding. The elastic field generated both in the disc and outer medium due to the misfit size of the circular disc is found. The complex variable technique is used. The stress intensity at the crack tip has also been calculated. It is shown that if the straight crack is near the circular hole, then the stresses in the vicinity of the disc will be greatly affected, as expected.
Singularly Loaded Semi‐circular Plate with Clamped Diameter and Free Circular Edge
Authors: Bassali W. A. , Mahmood S. S. , Refai M. Y.
Published: July 2010

Explicit formulae are given for the deflections and stresses in a thin isotropic homogeneous semi‐circular plate subject to an isolated load on the radius of symmetry, clamped along the diameter and free along the circular boundary. Two methods are used and numerical values of deflections, moments and shears based on the theory are provided in tables and curves. Results obtained by the two methods are in good agreement.
Die Existenz von Lösungen der Gleichungen, welche die Strömung inkompressibler mikropolarer Flüssigkeiten beschreiben
Authors: Lange H.
Published: July 2010

Der Verfasser untersucht mit Hilfe funktionalanalytischer Methoden die Anfangsrandwertaufgabe der Gleichungen, welche die inkompressible Strömung von mikropolaren Flüssigkeiten beschreiben. Dabei handelt es sich um zähe Flüssigkeiten, deren Volumenelementen Mikrorotationseffekte (insbesondere Mikrorotationsträgheit) zugeschrieben werden können.
Penalty Function Methods for the Numerical Solution of Nonlinear Obstacle Problems with Finite Elements
Authors: Werner W.
Published: July 2010

A class of penalty function methods for the solution of nonlinear variational inequalities with obstacles <–Au, v–u> ⩽ 0 für alle v ⩾ ψ in the Sobolev space W1, p (ω) is studied. The (nonlinear) penalty equations are solved by finite element techniques; the order of convergence of this procedure which depends on the regularity of the solution as well as on the finite elements used is investigated.
Squeeze Film Theory for Cosserat Fluids
Authors: Ahmadi Goodarz
Published: July 2010

The fundamental theory of squeeze film of fluids with inner structure is considered. The basic equations of motion of Cosserat fluids are reviewed. The special case of creeping parallel flow is investigatd and the expression for the velocity distribution in a narrow channel is derived. The variation of film bearing capacity with film thickness and inner structure length scale is calculated and the expression for time‐height relationship is also obtained and discussed. The limits of small and large fluids inner structure length measure are fconsidered and simple expressions for the load supporting capacity and time‐height relationship are derived. The results are plotted in several figures. The inner structure of the Cosserat fluid is also estimated form the existing experimental data for thin squeeze films.
Existenz‐ und Einzigkeitsprobleme für instationäre Strömungen in offenen Gerinnen
Authors: Förste J.
Published: July 2010

Für sehr breite Rechteckgerinne wird die zeitliche Entwicklung einer Wasserwelle betrachtet. Es werden Existenz‐, Einzigkeits‐ und Stabilitätsfragen untersucht.
On an Analytical Determination of Initial Points of Crack Propagation
Authors: Fischer K.‐F.
Published: July 2010

In the present paper, a possibility of determination of initial points of crack propagation in front of the crack tip is investigated. This possibility consists in the fact that apart from the first term of the series solution for the elastic field variables in crack tip vicinity further terms are considered in the formulation of characteristic quantities for crack judgment. Above all an extended Sih‐Criterion is presented. A qualitatively new information results in the determination of hypothetical initial points of crack propagation in front of the crack tip. We obtain similar results if we consider the extended stressparameter‐criterion and the extended multi‐axial‐value‐criterion.
Stabilitätseigenschaften adeptiver Runge‐Kutta‐Verfahren
Authors: Strehmel K.
Published: July 2010

Zur numerischen Behandlung von steifen Anfangswertaufgaben wird eine Klasse adaptiver Runge‐Kutta‐Verfahren betrachtet. Unter Beibehaltung der Konsistenzordnung erfordern sie nur gelegentlich eine Berechnung der Jacobi‐Matrix. Das Stabilitätsverhalten der adaptiven Verfahren bei großen Schrittweiten wird bezüglich des von Prothero und Robinson vorgeschlagenen skalaren Anfangswertproblems diskutiert. Die Wirksamkeit der adaptiven Verfahren wird durch einige steife Anfangswertaufgaben belegt.
2D elastic scattering of a plane dyadic wave by a small rigid body and cavity
Authors: Sevroglou V. , Vafeas P.
Published: July 2010

In this paper the scattering problem of the disturbance of a plane dyadic wave by a rigid body or a cavity, in two‐dimensional elastodynamics is considered. The direct scattering problems are formulated in a dyadic form, and in each case, the corresponding longitudinal and transverse far‐field scattering amplitudes are presented. We provide the necessary energy considerations and expressions for the differential and the scattering cross‐section due to plane wave dyadic incidence. Next, the rigid body and cavity are considered to be small and are illuminated by a plane dyadic field. Finally, relative results for low‐frequency scattering are obtained, and similar corresponding expressions for energy functionals in the far‐field along with expressions for the differential and the total scattering cross‐section are recovered as special cases.
Extensions of Kantorovich theorem to complementarity problem
Authors: Wang Z.
Published: July 2010

The Kantorovich theorem is extended to Newton‐Josephy method for solving nonlinear complementarity problem. All the convergence conditions established in this article can be tested in the digital computer.
Small strain oscillations of an elastoplastic Kirchhoff plate
Authors: Guenther R.B. , Krejčí P. , Sprekels J.
Published: July 2010

The two dimensional equation for transversal vibrations of an elastoplastic plate is derived from a general three dimensional system with a single yield tensorial von Mises plasticity model in the five dimensional deviatoric space. It leads after dimensional reduction to a multiyield three dimensional Prandtl‐Ishlinskii hysteresis model whose weight function is explicitly given. The resulting partial differential equation with hysteresis is solved by means of viscous approximations and a monotonicity argument.
Displacement control in time‐adaptive non‐linear finite‐element analysis
Authors: Hartmann S. , Quint K.J. , Hamkar A.‐W.
Published: July 2010

On the one hand, displacement controlled processes are frequently applied in Computational Mechanics using the finite‐element method, on the other hand, there are some shortcomings regarding the study and the presentation of this particular case. In this article, we focus our theoretical considerations on quasi‐static problems with constitutive equations of evolutionary type. In this case, it is currently known that the solution procedure of global and local iterations within the “Newton‐Raphson method” is related to the method of lines, where one arrives at a system of differential‐algebraic equations after the spatial discretization by means of the finite element method. This could be solved by means of the Backward‐Euler method or more appropriately using time‐adaptive, stiffly accurate, diagonally implicit Runge‐Kutta methods in combination with the Multilevel‐Newton method. In this respect the theoretical basis of currently applied implicit non‐linear finite element analyses is extended to displacement controlled processes. In this article, the calculation of the reaction forces using the method of Lagrange multipliers and the penalty method are of special interest in view of the new DAE‐approach. Accordingly, an important objective lies in a consistent notation so that the dependence of known and unknown variables as well as the transition from local to global level becomes obvious. These investigations are of utmost importance for micro‐macro homogenization techniques in FE$^2$ approaches and the development of new global time and space‐adaptive integration methods.