bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical vapour deposited carbon nanotube coated microelectrodes for intracortical neural recording
Authors: Castagnola Elisa , Ansaldo Alberto , Fadiga Luciano , Ricci Davide
Published: August 2010

Implantable electrodes are one of the most common tools in electrophysiology research, both for acute recording of intracortical signals and for chronical experiments. A stable low‐impedance electrode to tissue interface is fundamental to obtain reliable, long term recordings of the central nervous system activity. Commonly used metal electrodes do not fully meet such requirements, as their surface often degrades in time and they have high impedance. Nanostructured coatings, such as platinum black in the past and more recently conductive polymers, have been largely investigated as means to improve the electrodes for in vivo recording. With the same purpose, carbon nanotubes (CNTs) composite coatings have been obtained by chemical and electrochemical methods. In the present work we have used reference commercial microelectrodes for in vivo intracortical recording made from quartz insulated platinum/tungsten wires, mechanically ground, as a substrate to directly grow CNTs in situ by chemical vapour deposition. The analysis of the electrochemical and morphological properties of the obtained CNT coatings is presented and discussed.
Physicochemical characterization of the Pd/MWCNTs catalysts for fuel cell applications
Authors: Mikolajczuk Anna , Borodzinski Andrzej , Stobinski Leszek , Kedzierzawski Piotr , Lesiak Beata , Kövér László , Tóth József , Lin Hong‐Ming
Published: August 2010

The multiwall carbon nanotubes (MWCNTs) supported Pd catalyst, prepared by the polyol method and reduced in 5% of H2 in Ar atmosphere at temperature of 200 °C, exhibits high activity in electrooxidation of formic acid, whereas, the same catalyst calcinated at temperature of 250 °C in 100% of Ar is inactive. The structural and chemical properties of the catalyst surfaces after reducing and calcination treatments were investigated using electron spectroscopy. The catalytically active sample indicated smaller O content, with the same content of Pd and C at the surface. Simultaneously, the content of carbon–oxygen–hydrogen groups, i.e., carboxyl, carbonyl, ester, ether, and acid anhydride, was lower. In the surface layer of both catalysts, three chemical Pd forms were observed: Pd metallic crystallites, PdO and Pd in organic matrix. In active catalyst, similar content of Pd crystallites and smaller content of PdO were observed. The differences in activity of the investigated Pd/MWCNTs catalysts after reduction and calcination result from the amorphous carbon covering the PdO/Pd nanoparticles, where the PdO layer is of larger thickness for inactive catalyst. This overlayer is removed after reduction in 5% of H2 in Ar atmosphere at temperature of 200 °C.
Characterization of InGaGdN layers prepared by molecular beam epitaxy
Authors: Tawil Siti Nooraya Mohd , Kakimi Rina , Krishnamurthy Daivasigamani , Emura Shuichi , Tambo Hiroyuki , Hasegawa Shigehiko , Asahi Hajime
Published: August 2010

Gd‐doped InGaN layers were prepared by plasma‐assisted molecular‐beam epitaxy in search of new functional diluted magnetic semiconductors for their potential use in spintronics. The local structure around the Gd atoms was examined by the Gd LIII‐edge of X‐ray absorption fine structure. It was found that the majority of Gd atoms substitutionally occupied the cation sites in the InGaGdN layers. Clear hysteresis and saturation magnetization were observed from the magnetization versus field curves examined by means of a superconducting quantum interference device magnetometer at low and room temperatures. In addition, the incorporation of extra shallow donors by co‐doping InGaN with both Gd and Si showed higher magnetization than the undoped InGaGdN. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Implementing ICH Q10 for clinical trials: the bioanalytical quality standard initiative (BQSI) for bioavailability and bioequivalence
Authors: Smith Jon Kirk , Aubin Hope M.
Published: August 2010

Over the last two years, a pharmaceutical industry consortium has been leading the initiative to develop an industry/agency‐acceptable guideline, applicable to standardizing laboratory and quality management practices for bioanalytical studies, supporting clinical trials. Participating in the initiative are representatives from a number of leading pharmaceutical companies (innovator and generic) and contract research organizations. The initiative was born out of the industry‐wide recognition that neither the United States Food and Drug Administration (FDA) or European Medicines Agency (EMEA) regulation, nor International Conference on Harmonization (ICH) or Organization for Economic Cooperation and Development (OECD) consensus standards, addresses laboratory analysis in support of clinical trials. Copyright © 2010 John Wiley & Sons, Ltd.
Implementation of a new urban energy budget scheme into MetUM. Part II: Validation against observations and model intercomparison
Authors: Porson A. , Clark P. A. , Harman I. N. , Best M. J. , Belcher S. E.
Published: August 2010

In the first part of this article, we introduced a new urban surface scheme, the Met Office – Reading Urban Surface Exchange Scheme (MORUSES), into the Met Office Unified Model (MetUM) and compared its impact on the surface fluxes with respect to the current urban scheme. In this second part, we aim to analyze further the reasons behind the differences. This analysis is conducted by a comparison of the performance of the two schemes against observations and against a third model, the Single Column Reading Urban model (SCRUM). The key differences between the three models lie in how each model incorporates the heat stored in the urban fabric and how the surface‐energy balance is coupled to the underlying substrate.

The comparison of the models with observations from Mexico City reveals that the performance of MORUSES is improved if roof insulation is included by minimizing the roof thickness. A comparison of MORUSES and SCRUM reveals that, once insulation is included within MORUSES, these two models perform equally well against the observations overall, but that there are differences in the details of the simulations at the roof and canyon level. These differences are attributed to the different representations of the heat‐storage term, specifically differences in the dominant frequencies captured by the urban canopy and substrate, between the models. These results strongly suggest a need for an urban model intercomparison exercise. Copyright © 2010 Royal Meteorological Society and Crown Copyright
Correction of ‘Estimating observation impact without adjoint model in an ensemble Kalman filter’
Authors: Li Hong , Liu Junjie , Kalnay Eugenia
Published: August 2010

The ensemble sensitivity method proposed by Liu and Kalnay (2008) to estimate the impact of observations on reducing forecast error is shown to have a slight error and is corrected here. The corrected formula captures the actual forecast error reduction better and removes the positive bias in the estimation introduced by the original formula. Copyright © 2010 Royal Meteorological Society
Implementation of a new urban energy budget scheme in the MetUM. Part I: Description and idealized simulations
Authors: Porson A. , Clark P. A. , Harman I. N. , Best M. J. , Belcher S. E.
Published: August 2010

This paper describes the formulation of a new urban scheme, MORUSES (Met Office–Reading Urban Surface Exchange Scheme) for use in the Met Office Unified Model. The implementation of the new scheme ensures that (1) the new scheme offers more flexibility in the parametrization of the building properties, and hence provides a more realistic representation of the fluxes; (2) the bulk outputs are in satisfactory agreement with previous observational studies; and (3) the impact of the new scheme on the energy balance fluxes is similar to the impact of the current urban scheme when set up to mimic it. As well as having a better physical basis, MORUSES also gains in flexibility in applications and adaptations to different urban materials as well as urban planning. The new scheme represents the urban area as a composition of two tiles, a canyon and a roof, using a simple 2D geometry. Sensitivity analysis to canyon geometry and thickness of the roof canopy emphasizes the gain in flexibility captured by the new scheme. Copyright © 2010 Royal Meteorological Society and Crown Copyright
Generalized energy approach for calculating electron collision cross‐sections for multicharged ions in a plasma: Debye shielding model
Authors: Malinovskaya Svetlana V. , Glushkov Alexander V. , Khetselius Olga Yu. , Lopatkin Yury M. , Loboda Andrey V. , Nikola Ludmila V. , Svinarenko Andrey A. , Perelygina Tat'Yana B.
Published: August 2010

A uniform quantum energy approach for studying spectra of the multicharged ions in a plasmas and the electron‐ion collision cross sections is presented. The approach is based on formally exact QED theory by using the relativistic Dirac Hamiltonian for electron–nuclear and electron–electron potentials, the gauge invariant scheme of generation for the optimal one‐quasiparticle representation and the Debye shielding model. The measured and calculated electron‐collisional excitation cross sections for Ne‐like barium ion for different values of the incident electron energy are presented and analyzed. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
vsLab—An implementation for virtual high‐throughput screening using AutoDock and VMD
Authors: Cerqueira N. M. F. S. A. , Ribeiro J. , Fernandes P. A. , Ramos M. J.
Published: August 2010

Molecular docking is a key tool in structural molecular biology and computer‐assisted drug design. The goal of ligand–protein docking is to predict the predominant binding mode(s) of a ligand with a protein of known three‐dimensional structure. There is much docking software that has been successfully used in a myriad of keystone problems; however, as commonly happens with most of the scientific software, the programs are often complex and a deep knowledge is required for the common user to carry out standard steps. This is an obstacle and a cornerstone issue for the research teams in the fields of chemistry and the life sciences, who are interested in conducting this kind of calculations but do not have enough programing skills. To overcome these limitations, we have designed vsLab (virtual screening lab), an easy‐to‐use graphical interface for the well‐known molecular docking software AutoGrid/AutoDock that has been included into VMD as a plug‐in. This program allows almost anyone to use AutoDock and AutoGrid for simple docking or for virtual screening campaigns without requiring any deep knowledge about these techniques. The potential associated to this software makes it an attractive choice for more advanced users that can use vsLab to increase workflow and productivity of everyday tasks. The program can be freely obtained athttp://www.fc.up.pt/pessoas/nscerque/vsLab/vLab/HomePage.html© 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
A quantum mechanical study of novel potential inhibitors of cytochrome bc1 as antimalarial compounds
Authors: Rodrigues Tiago , Dos Santos Daniel J. V. A. , Moreira Rui , Lopes Francisca , Guedes Rita C.
Published: August 2010

Cytochrome bc1 is a validated drug target of Plasmodium falciparum, the parasite that causes the most lethal form of malaria. The inhibition of cytochrome bc1 leads to the shutdown of the mitochondrial metabolism and the consequent arrest of pyrimidine biosynthesis essential for parasite development. Aiming to rationalize the stereoelectronic properties and extend the knowledge on a novel series of 4‐pyridonimines guiding the search of antimalarial drugs, we carried out an extensive DFT comparative characterization. Results show electronic similarity with clopidol, a known bc1 complex inhibitor containing the 4(1H)‐pyridone scaffold. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Direct mixed‐quantum/classical computations of k(T). An analysis of the use of different coordinate systems
Authors: Clavero Esteban , Palma Juliana
Published: August 2010

We have obtained three mixed‐quantum/classical schemes to directly calculate thermal rate constants through the evaluation of flux‐flux correlation function. These schemes are appropriate to treat three‐atom reactions, but could be easily extended to larger systems. One of the schemes uses normal mode coordinates, defined at the transition state. The others use hyperspherical coordinates. The proposed algorithms were applied to the H + H2 → H2 + H reaction, and their accuracy was tested by comparison with full‐quantum results. In this article, we present the derivation of the three mixed‐quantum/classical schemes, describe the details of their implementation, and discuss the quality of their results. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Quantum chemical and dynamical approaches to intra and intermolecular kinetics: The CnH2nO (n = 1, 2, 3) molecules
Authors: Elango Munusamy , Maciel Glauciete S. , Lombardi Andrea , Cavalli Simonetta , Aquilanti Vincenzo
Published: August 2010

An account is given of isomerization and decomposition paths in the title molecules, as obtained by characterizing stable isomers and transition states using quantum chemistry and reaction rate theories. For n = 1 (formaldehyde) intrinsic reaction paths are calculated to provide rates for decomposition mechanisms dominated by quantum mechanical tunneling. The n = 2 closed shell isomers are acetaldehyde, ethylene oxide, and vinyl alcohol, which interconvert and decompose through alternative paths. For n = 3, the very large number of isomers are characterized using an efficient automatic search algorithm recently made available by Ohno and Maeda. Interconversion paths are also found, including those involving chiral change mechanisms for propylene oxide. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Post‐Hartree‐Fock (MP2 and MP4) study on decomposition of nitrous oxide on the nonframework AlO(+) site in ZSM‐5 zeolite
Authors: Solkan V. N. , Zhidomirov G. M.
Published: August 2010

The reaction mechanism for nitrous oxide (N2O) decomposition has been studied on AlO(+) site in AlO‐ZSM‐5 zeolite using the MP2/6‐31+G(d) method. The active centers were taken to be mononuclear [AlO]+ and [AlO2]+, and the surrounding portion of the zeolite was represented by a 3T cluster, namely [AlSi2O4H8]−. The first elementary step of N2O decomposition involves the formation of [AlO2]+ and the release of N2. The metal‐peroxo species produced in this step then reacts with N2O again, to release N2 and form [AlO3]+. The calculated activation energies at MP2 level for N2O dissociation on AlO‐ZSM‐5 and AlO2‐ZSM‐5 are 26.9 and 38.2 kcal/mol at 298 K, respectively. The calculated reaction enthalpies at MP2 level for N2O dissociation on AlO‐ZSM‐5 and AlO2‐ZSM‐5 are −25.1 and −21.3 kcal/mol at 298 K, respectively. Four‐order perturbation theory (MP4//MP2) predicts that the activation barriers for N2O dissociation at 298 K on AlO‐ZSM‐5 and AlO2‐ZSM‐5 are 12.9 and 29.5 kcal/mol, respectively. The calculated energy for desorption of singlet O2 from the 3T−[Al(O)3]+ cluster at MP2 level is 46.4 kcal/mol. When one takes into account the entropy gained on desorption of singlet O2, the contribution of entropy to the free energy of desorption is TΔS = 11.1 kcal/mol at 298 K. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Substitutional sites of nitrogen atoms in carbon nanotubes and their influence on field‐emission characteristics
Authors: Bulusheva Lyubov G. , Sedelnikova Olga V. , Okotrub Alexander V.
Published: August 2010

We studied the dependence of mutual position of substitutional nitrogen atoms on the diameter and helicity of carbon nanotubes by using a hybrid B3LYP method. It was found that nitrogen atoms prefer occupying the para‐site of a hexagon in armchair nanotubes and to be far apart in zigzag and chiral nanotubes. Even more preferable position for both zigzag and armchair nanotubes is nitrogen location in pentagonal rings at the tube caps. These results are supported by experimental data indicating low concentration of nitrogen (∼1 at%) in single‐wall carbon nanotubes. On the basis of the results of calculations, we plotted current–voltage dependences for initial and nitrogen‐doped carbon (CNx) nanotubes for elucidating the effect of nitrogen atoms configuration on field‐emission characteristics of nanotubes. Nitrogen doping of carbon armchair nanotubes was shown to reduce the voltage threshold and to increase the current density significantly. The improvement of field‐emission property for carbon zigzag nanotubes is expected when nitrogen atoms are near the tube tip. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
GEN1INT: A unified procedure for the evaluation of one‐electron integrals over Gaussian basis functions and their geometric derivatives
Authors: Gao Bin , Thorvaldsen Andreas J. , Ruud Kenneth
Published: August 2010

We propose a unified procedure for evaluating a variety of one‐electron integrals and their (arbitrary‐order) geometric derivatives by using a generalized one‐electron operator, which is formed as the product of four operators: (1) a scalar depending on the displacement of the two basis function centers A and B: (Ax − Bx)(Ay − By)(Az − Bz), (2) a multipole moment operator (x − Mx)(y − My)(z − Mz) around origin M, (3) an arbitrary central potential operator f(|r − C|) around center C, and (4) an electronic differential operator (∂/∂x)(∂/∂y)(∂/∂z). The use of Hermite Gaussian functions enables us to evaluate both the integrals and their geometric derivatives on a common footing. This unified computational scheme has been implemented in an open‐ended integral package GEN1INT, and interfaced to the DALTON program, using the Q5Cost library to ensure the portability of the code. Operators of the form f(|r − C|) = |r − C|−1, |r − C|−2, and Dirac delta function δ(r − C) have been implemented, and improvements in the evaluation of integrals involving the operator |r − C|−2 are proposed. The integral package GEN1INT can compute complicated one‐electron property integrals and their arbitrary‐order geometric derivatives, and is therefore expected to be a valuable tool when calculating higher order molecular properties, in particular, in combination with a recently proposed open‐ended quasi‐energy derivative approach (Thorvaldsen et al., J Chem Phys 2008, 129, 214108). © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Anchor ice rafting: Observations from the laramie river
Authors: Kempema Edward W. , Ettema Robert
Published: August 2010

Anchor ice rafting (transport of sediment by released anchor ice) occurs regularly on many ice‐affected rivers. However, rafting is poorly understood and there is scant quantitative information about it. This paper describes anchor ice formation and ice rafting observations made in the Laramie River, a small river in Wyoming. Anchor ice forms on cobble, gravel and sand substrates in the Laramie River. When released from the bed, anchor ice rafts sediment from all of these size classes. Observations suggest that anchor ice plays a substantial role transporting coarse fluvial sediment because anchor readily envelops large particles extending above the bed. A comparison of anchor‐ice rafted sediment with peak‐discharge bedload sediment shows that the largest sediment is transported downstream during the winter when flows are at a minimum. The largest ice‐rafted cobble identified in this study weighed 9.5 kg; peak floods are capable of moving sediment only about a hundredth of the cobble's weight. There is overlap in ice‐rafted and bedload sediment transport; both processes move significant amounts of sand‐sized material. The average sediment concentration in released, floating anchor ice samples was 22 g l−1. Copyright © 2010 John Wiley & Sons, Ltd.
Helical cell motions in a small ice‐covered meander river reach
Authors: Demers S. , Buffin‐Bélanger T. , Roy A. G.
Published: August 2010

The investigation of the flow field with a pulse‐coherent acoustic Doppler profiler has led to new high resolution observations of the secondary flow pattern occurring in a natural ice‐covered meander reach. Surveys were conducted during two successive winter periods with different ice conditions. Massive frazil ice accumulation was present during one of the survey and its influence on the flow pattern could be assessed. Results show that the primary flow is clearly deflected towards the outer bend. Secondary flows are one order of magnitude less than the primary flow and they display two stacked counter‐rotating helical cells pattern occurring at the entrance of the bend. This pattern is associated with the parabolic shape of the velocity profiles entering the bend. The pattern rapidly evolves downstream, reducing to one helical cell rotating in an opposite direction than what is observed in open channel flows. Flow mixing and morphological non‐uniformity are potential factors governing the development of the helical cells throughout the bend. Our observations show that a similar coherent flow pattern rapidly forms downstream of a massive frazil ice obstruction in the bend. Frazil ice does not constrain the formation of helical flow pattern in river bends. Copyright © 2010 John Wiley & Sons, Ltd.
An embedded DSP hardware encryption module for secure e‐commerce transactions
Authors: Hu J. , Hoang X. D. , Khalil I.
Published: August 2010

Cryptography is one of the key elements in providing security for modern e‐commerce systems. It is well known that software‐based encryption has built‐in security weaknesses due to storing and managing digital certificates/keys in a high‐risk environment such as a local hard disk or software. This makes embedded hardware encryption a superior solution. However, most existing embedded hardware encryption modules need additional dedicated software in order to implement a secure e‐commerce application, which increases cost as well as adds complexity. In this paper, a new embedded hardware DSP (digital signal processor) encryption module, using the RSA (Rivest, Shamir, and Adleman) algorithm, is developed for secure e‐commerce transactions from the client side. The goal is to seamlessly integrate the embedded DSP hardware encryption module, which combines computational power and flexibility in programming, with a widely available web browser that provides the required e‐commerce functions. The integrated system can store and process security sensitive data inside the plug‐in hardware. The proposed scheme tries to maximize security strength while limiting overheads by utilizing a widely available web browser to perform e‐commerce functions such as product searching, etc. A fully functional web e‐commerce system has been developed as a proof of concept. Our major contribution is a design of a functional RSA plug‐in encryptor which can store and encrypt sensitive information originated from the e‐commerce process using standard web browsers. Implementation details addressing challenging issues such as big integer, large message, and communication components have been provided which have never been reported in the public literature. This can be very useful for real‐life industry security applications. Copyright © 2010 John Wiley & Sons, Ltd.
The effect of salvage therapy on survival in a longitudinal study with treatment by indication
Authors: Kennedy Edward H. , Taylor Jeremy M. G. , Schaubel Douglas E. , Williams Scott
Published: August 2010

We consider using observational data to estimate the effect of a treatment on disease recurrence, when the decision to initiate treatment is based on longitudinal factors associated with the risk of recurrence. The effect of salvage androgen deprivation therapy (SADT) on the risk of recurrence of prostate cancer is inadequately described by the existing literature. Furthermore, standard Cox regression yields biased estimates of the effect of SADT, since it is necessary to adjust for prostate‐specific antigen (PSA), which is a time‐dependent confounder and an intermediate variable. In this paper, we describe and compare two methods which appropriately adjust for PSA in estimating the effect of SADT. The first method is a two‐stage method which jointly estimates the effect of SADT and the hazard of recurrence in the absence of treatment by SADT. In the first stage, PSA is predicted in the absence of SADT, and in the second stage, a time‐dependent Cox model is used to estimate the benefit of SADT, adjusting for PSA. The second method, called sequential stratification, reorganizes the data to resemble a sequence of experiments in which treatment is conditionally randomized given the time‐dependent covariates. Strata are formed, each consisting of a patient undergoing SADT and a set of appropriately matched controls, and analysis proceeds via stratified Cox regression. Both methods are applied to data from patients initially treated with radiation therapy for prostate cancer and give similar SADT effect estimates. Copyright © 2010 John Wiley & Sons, Ltd.
Accuracy and cut‐off point selection in three‐class classification problems using a generalization of the Youden index
Authors: Nakas, Christos T. , Alonzo Todd A. , Yiannoutsos Constantin T.
Published: August 2010

We study properties of the indexJ3, defined as the accuracy, or the maximum correct classification, for a given three‐class classification problem. Specifically, usingJ3one can assess the discrimination between the three distributions and obtain an optimal pair of cut‐off pointsc1<c2in the sense that the sum of the correct classification proportions will be maximized. It also serves as the generalization of the Youden index in three‐class problems. Parametric and non‐parametric approaches for estimation and testing are considered and methods are applied to data from an MRS study on human immunodeficiency virus (HIV) patients. Copyright © 2010 John Wiley & Sons, Ltd.
A sequential Cox approach for estimating the causal effect of treatment in the presence of time‐dependent confounding applied to data from the Swiss HIV Cohort Study
Authors: Gran Jon Michael , Røysland Kjetil , Wolbers Marcel , Didelez Vanessa , Sterne Jonathan A. C. , Ledergerber Bruno , Furrer Hansjakob , von Wyl Viktor , Aalen Odd O.
Published: August 2010

When estimating the effect of treatment on HIV using data from observational studies, standard methods may produce biased estimates due to the presence of time‐dependent confounders. Such confounding can be present when a covariate, affected by past exposure, is both a predictor of the future exposure and the outcome. One example is the CD4 cell count, being a marker for disease progression for HIV patients, but also a marker for treatment initiation and influenced by treatment. Fitting a marginal structural model (MSM) using inverse probability weights is one way to give appropriate adjustment for this type of confounding. In this paper we study a simple and intuitive approach to estimate similar treatment effects, using observational data to mimic several randomized controlled trials. Each ‘trial’ is constructed based on individuals starting treatment in a certain time interval. An overall effect estimate for all such trials is found using composite likelihood inference. The method offers an alternative to the use of inverse probability of treatment weights, which is unstable in certain situations. The estimated parameter is not identical to the one of an MSM, it is conditioned on covariate values at the start of each mimicked trial. This allows the study of questions that are not that easily addressed fitting an MSM. The analysis can be performed as a stratified weighted Cox analysis on the joint data set of all the constructed trials, where each trial is one stratum. The model is applied to data from the Swiss HIV cohort study. Copyright © 2010 John Wiley & Sons, Ltd.
The positivity ratio and functioning under stress
Authors: Shrira Amit , Palgi Yuval , Wolf Jonathan Jacob , Haber Yeela , Goldray Orit , Shacham‐Shmueli Einat , Ben‐Ezra Menachem
Published: August 2010

The positivity ratio reflects the ratio of positive affect to negative affect. In two studies, the authors investigated the relationship between positivity ratio and functioning under stress. Study 1 examined gastric cancer patients (N = 123) and Study 2 explored hospital personnel exposed to missile attacks (N = 84). In both studies, there was a curvilinear relationship between positivity ratio and functioning. As the positivity ratio increased there was a steep decrease in maladaptive functioning. The decrease in maladaptive functioning leveled at around a ratio of three, from which point maladaptive functioning stayed the same, or even started to mildly ascend, till the maximum positivity ratio score. Taken together, this finding indicates that a moderate positivity ratio is sufficient for optimal functioning at the midst of stress. Implications for the role of affect in coping with stress are discussed. Copyright © 2010 John Wiley & Sons, Ltd.
On the stress by photoperiod, temperature and noise as possible causes of genomic damaging in an animal model
Authors: Adam Mônica Lúcia , Torres Maria Fernanda Pioli , Franci Ana Cláudia , Sponchiado Graziela , Torres Rodrigo Augusto , Correia Maria Tereza dos Santos
Published: August 2010

Stress is a defense mechanism of an organism and is directly related to homeostasis, which is the equilibrium state of the multitude of organism systems, both among each other and with the environment. Given that stress is a major cause of cellular instability, it is directly related to its loss homeostasis. The present study assessed the changes caused by stress on the genetic material of Rattus norvegicus using micronuclei analysis. A total of 10 males were studied by being submitted to continuous stress from photoperiod, temperature and noise for 26 days. Peripheral blood samples were obtained immediately before submitting the animals to stress, as well as on the fifteenth and twenty‐sixth days afterwards. Blood smears were stained with Giemsa and the slides were analyzed using light microscopy. Approximately 3,000 polychromatic erythrocytes from each animal were observed and classified as either normal or micronucleated. The analysis indicated a frequency of 0.0012014 for the control sample, whereas samples on days 15 and 26 had frequencies of 0.0035458 and 0.0496850, respectively. A statistical analysis revealed statistically significant differences among the studied cell samples (ANOVA p < 0.00001, significance of 5%). Therefore, the presence of micronuclei in the studied samples is consistent with a cause/effect relationship. Copyright © 2010 John Wiley & Sons, Ltd.
A secure migration process for mobile agents
Authors: Malik Najmus Saqib , Ko David , Cheng Harry H.
Published: August 2010

This article describes a decentralized secure migration process of mobile agents between Mobile‐C agencies. Mobile‐C is an IEEE Foundation for Intelligent Physical Agents (FIPA) standard compliant multi‐agent platform for supporting C/C++ mobile and stationary agents. Mobile‐C is specially designed for mechatronic and factory automation systems where malicious agents may cause physical damage to machinery and personnel. As a mobile agent migrates from one agency to another in an open network, the security concern of mobile agent systems should not be neglected. Security breaches can be minimized considerably if an agency only accepts mobile agents from agencies known and trusted by the system administrator. In Mobile‐C, a strong authentication process is used by sender and receiver agencies to authenticate each other before agent migration. The security framework also aims to guarantee the integrity and confidentiality of the mobile agent while it is in transit. This assures that all agents within an agency framework were introduced to that framework under the supervision and permission of a trusted administrator. The Mobile‐C Security protocol is inspired from the Secure Shell (SSH) protocol, which avoids a single point of failure since it does not rely on a singular remote third party for the security process. In this protocol, both agencies must authenticate each other using public key authentication, before a secure migration process. After successful authentication, an encrypted mobile agent is transferred and its integrity is verified by the receiver agency. This article describes the Mobile‐C secure migration process and presents a comparison study with the SSH protocol. The performance analysis of the secure migration process is performed by comparing the turnaround time of mobile agent with and without security options in a homogeneous environment. Copyright © 2010 John Wiley & Sons, Ltd.
Concise Review: Stem Cells As an Emerging Platform for Antibody Therapy of Cancer
Authors: Frank Richard T. , Najbauer Joseph , Aboody Karen S.
Published: August 2010

Monoclonal antibodies are important tools for cancer therapy, however, three factors limit their effectiveness: toxicity, poor tumor penetration, and inability to cross the blood-brain barrier. This review discusses the emerging field of stem cell-mediated antibody delivery and how this approach may improve antibody therapy of cancer by overcoming these obstacles.
Linguistic evidence and grammatical theory
Authors: Schütze Carson T.
Published: August 2010

This article surveys the major kinds of empirical evidence used by linguists, with a particular focus on the relevance of the evidence to the goals of generative grammar. After a background section overviewing the objectives and assumptions of that framework, three broad kinds of data are considered in the three subsequent sections: corpus data, judgment data, and (other) experimental data. The perspective adopted is that all three have their place in the linguist's toolbox: they have relative advantages and disadvantages that often complement one another, so converging evidence of more than one kind can reasonably be sought in many instances. Points are illustrated mainly with examples from syntax, but often can be easily translated to other levels (e.g., phonology, morphology, semantics, and pragmatics). WIREs Cogni Sci 2011 2 206–221 DOI: 10.1002/wcs.102

This article is categorized under:

Linguistics > Language in Mind and Brain

Linguistics > Linguistic Theory
Role of systems pharmacology in understanding drug adverse events
Authors: Berger Seth I. , Iyengar Ravi
Published: August 2010

Systems pharmacology involves the application of systems biology approaches, combining large‐scale experimental studies with computational analyses, to the study of drugs, drug targets, and drug effects. Many of these initial studies have focused on identifying new drug targets, new uses of known drugs, and systems‐level properties of existing drugs. This review focuses on systems pharmacology studies that aim to better understand drug side effects and adverse events. By studying the drugs in the context of cellular networks, these studies provide insights into adverse events caused by off‐targets of drugs as well as adverse events‐mediated complex network responses. This allows rapid identification of biomarkers for side effect susceptibility. In this way, systems pharmacology will lead to not only newer and more effective therapies, but safer medications with fewer side effects. WIREs Syst Biol Med 2011 3 129–135 DOI: 10.1002/wsbm.114

This article is categorized under:

Analytical and Computational Methods > Computational Methods

Translational, Genomic, and Systems Medicine > Therapeutic Methods

Analytical and Computational Methods > Topological Methods
Pancreaticobiliary Reflux in Patients with and without Cholelithiasis: Is It a Normal Phenomenon?
Authors: Beltrán Marcelo A. , Contreras Mario A. , Cruces Karina S.
Published: August 2010

Background

Pancreaticobiliary reflux is a pathologic phenomenon occurring in patients with gallstones. However, the occurrence of pancreaticobiliary reflux has not been studied in patients without gallstones. The objective of the present study was to measure the bile levels of amylase and lipase in patients without gallstones submitted to cholecystectomy as part of another surgical procedure, and to compare these values with the bile levels of amylase and lipase of patients submitted to cholecystectomy for gallstone disease.

Patients and methods

A prospective observational and comparative study was designed. A sample of 136 consecutive patients was included. Amylase and lipase levels were measured in bile. At our institution, normal plasma concentrations of amylase are 28–100 IU/l and lipase 13–60 IU/l. Normal values for pancreatic enzyme concentrations in bile have not been established. Therefore, bile amylase and lipase concentrations exceeding normal plasma concentrations were deemed to be elevated.

Results

Of the patients in the present study, 103 (76%) had gallstones and 33 (24%) had healthy gallbladders without gallstones. According to normal plasma levels for amylase and lipase, these enzymes in bile were elevated in 83.5% patients with gallstones, compared to elevated levels of amylase in 6% patients and lipase in 3% patients without gallstones (P < 0.0001).

Conclusions

Pancreaticobiliary reflux is a common phenomenon in patients with gallstones and an uncommon phenomenon in patients with healthy gallbladders without gallstone disease.
Inhibition of Insulin and T3‐Induced Fatty Acid Synthase by Hexanoate
Authors: Akpa Murielle M. , Point Floriane , Sawadogo Sabine , Radenne Anne , Mounier Catherine
Published: August 2010

Fatty acid synthase (FAS) is responsible for the de novo synthesis of palmitate and stearate. This enzyme is activated by insulin and T3, and inhibited by fatty acids. In this study, we show that insulin and T3have an inducing effect on FAS enzymatic activity, which is synergetic when both hormones are present. Octanoate and hexanoate specifically inhibit this hormonal effect. A similar inhibitory effect is observed at the level of protein expression. Transient transfections in HepG2 cells revealed that hexanoate inhibits, at least in part, FAS at a transcriptional level targeting the T3response element (TRE) on the FAS promoter. The effect of C6 on FAS expression cannot be attributed to a modification of insulin receptor activation or to a decrease in T3entry in the cells. Using bromo‐hexanoate, we determined that hexanoate needs to undergo a transformation in order to have an effect. When incubating cells with triglyceride–hexanoate or carnitine–hexanoate, no effect on the enzymatic activity induced by insulin and T3is observed. A similar result was obtained when cells were incubated with betulinic acid, an inhibitor of the diacylglycerol acyltransferase. However, the incubation of cells with Triacsin C, a general inhibitor of acyl‐CoA synthetases, completely reversed the inhibitory effect of hexanoate. Our results suggest that in hepatic cells, hexanoate needs to be activated into a CoA derivative in order to inhibit the insulin and T3‐induced FAS expression. This effect is partially transcriptional, targeting the TRE on the FAS promoter.
Psychological changes and the resolution of acute neck pain after a motor vehicle accident
Authors: Vangronsveldl Karoline L. , Morleyl Stephen , Petersl Madelon L. , Vlaeyenl Johan W. , Goossensl Mariëlle E.
Published: August 2010

This study examines the changes in self‐perception during resolution of an acutely painful neck injury sustained in a motor vehicle accident. We tested predictions from self‐discrepancy theory and a model of self‐pain enmeshment. Measures of discrepancy between the current (actual) self and both the ideal and feared‐for self were predicted to remain stable over a 21‐day recovery period whereas a measure of enmeshment was predicted to decrease as pain resolved. We also examined the relationship between daily ratings of achievement in several domains and participants perceived ideal performance. Sixty patients with possible acute neck injury recruited within 1 month after a motor vehicle accident gave consent and data were obtained from 42 participants. Standard questionnaire measures of pain, disability, fear of movement, pain catastrophizing and self‐discrepancies, self‐pain enmeshment and data from diaries (measures of pain, mood, self‐discrepancies, pain catastrophizing and fear of movement) were obtained.

In general the relationships between the measures of self‐discrepancy and enmeshment and mood were in accord with both theoretical predictions and previous observations. Resolution of pain was associated with a reduction in enmeshment but not to change in self‐discrepancy. Multilevel analyses of the diary data showed that concordance between actual and ideal performance increased over the 21 days of data collection. These data provide preliminary support for aspects of self‐discrepancy theory and the self‐pain enmeshment model.
Adolescent pregnancy outcomes and risk factors in Malaysia
Authors: Omar Khairani , Hasim Suriati , Muhammad Noor Azimah , Jaffar Aida , Hashim Syahnaz Mohd , Siraj Harlina Halizah
Published: August 2010

Objective

To assess the outcomes and risk factors of adolescent pregnancies in 2 major hospitals in Malaysia.

Methods

We conducted a case‐control study of pregnant girls aged 10 through 19 years. The controls were women aged 20 through 35 years who did not become pregnant in their adolescence. Cases and controls were matched for parity and place of delivery. Data were collected from questionnaires and the hospitals’ medical records.

Results

The study included 102 cases and 102 controls. There were significant associations between adolescent pregnancy and low education level, low socioeconomic status, being raised by a single parent, not engaging in extracurricular school activities, engaging in unsupervised activities with peers after school, and substance abuse (P < 0.05 for all); being anemic, being unsure of the expected delivery date, and having few antenatal visits and a late delivery booking; and low Apgar scores and perinatal complications.

Conclusion

Adolescent pregnancies are high‐risk pregnancies. Better sexual health strategies are required to address the associated complications.
Are stock returns still mean‐reverting?
Authors: Mukherji Sandip
Published: August 2010

This study uses a powerful nonparametric block bootstrap method and fresh data to examine the unresolved issue of mean reversion in stock returns. The results show that both large and small company stocks experienced significant mean reversion in returns for periods of 1 through 5 years during 1926–1966. In 1967–2007, there was significant mean reversion in 5‐year returns of large company stocks, and 1‐, 4‐, and 5‐year returns of small company stocks. The findings indicate that, although mean reversion in stock returns has weakened in recent decades, it persists, particularly for small company stocks.
Zooplankton at a seamount in the eastern Mediterranean: distribution and trophic interactions
Authors: Denda Anneke , Christiansen Bernd
Published: August 2010

The study focuses on the question, how a seamount in the oligotrophic eastern Mediterranean affects the zooplankton community, as compared to the open water. Zooplankton samples were taken with 333 µm nets at two sites, the Rhodes Basin and the Anaximenes Mountain, in December 2006. The samples were sieved into size fractions, and the composition, biomass, abundance and stable isotope signatures were analysed. In general, biomass and abundance of zooplankton were low, reflecting the oligotrophic character of the eastern Mediterranean, but zooplankton standing stocks were higher at the Rhodes Basin than at the Anaximenes Mountain. Stable isotope signatures showed, at a generally low level, enrichment in zooplankton taxa along the food chain within the different pelagic zones and from the surface to the deep-sea, but no significant differences between Rhodes Basin and the seamount were evident in the food web structure. The zooplankton community in the Anaximenes Mountain region in the northern Levantine Basin seems not to be influenced by a local seamount effect, despite the difference in standing stocks between the seamount and the Rhodes Basin. This seems to be driven by larger-scale upwelling and downwelling structures of cyclones and anticyclones, dominating the circulation in the area.
D-STEM: A Parallel Electron Diffraction Technique Applied to Nanomaterials
Authors: Ganesh K.J. , Kawasaki M. , Zhou J.P. , Ferreira P.J.
Published: August 2010

An electron diffraction technique called D-STEM has been developed in a transmission electron microscopy/scanning transmission electron microscopy (TEM/STEM) instrument to obtain spot electron diffraction patterns from nanostructures, as small as ∼3 nm. The electron ray path achieved by configuring the pre- and postspecimen illumination lenses enables the formation of a 1–2 nm near-parallel probe, which is used to obtain bright-field/dark-field STEM images. Under these conditions, the beam can be controlled and accurately positioned on the STEM image, at the nanostructure of interest, while sharp spot diffraction patterns can be simultaneously recorded on the charge-coupled device camera. When integrated with softwares such as GatanTMSTEM diffraction imaging and Automated Crystallography for TEM or DigistarTM, NanoMEGAS, the D-STEM technique is very powerful for obtaining automated orientation and phase maps based on diffraction information acquired on a pixel by pixel basis. The versatility of the D-STEM technique is demonstrated by applying this technique to nanoparticles, nanowires, and nano interconnect structures.
Dilution and Magnification Effects on Image Analysis Applications in Activated Sludge Characterization
Authors: Mesquita D.P. , Dias O. , Elias R.A.V. , Amaral A.L. , Ferreira E.C.
Published: August 2010

The properties of activated sludge systems can be characterized using image analysis procedures. When these systems operate with high biomass content, accurate sludge characterization requires samples to be diluted. Selection of the best image acquisition magnification is directly related to the amount of biomass screened. The aim of the present study was to survey the effects of dilution and magnification on the assessment of aggregated and filamentous bacterial content and structure using image analysis procedures. Assessments of biomass content and structure were affected by dilutions. Therefore, the correct operating dilution requires careful consideration. Moreover, the acquisition methodology comprising a 100× magnification allowed data on aggregated and filamentous biomass to be determined and smaller aggregates to be identified and characterized, without affecting the accuracy of lower magnifications regarding biomass representativeness.
Solar wind density influence on geomagnetic storm intensity
Authors: Weigel R. S.
Published: August 2010

Solar wind density has been argued to have a strong effect on geomagnetic storms. Elevated solar wind density tends to occur in time intervals when the solar wind electric field is large. This complicates the analysis required to identify a solar wind density influence because the solar wind electric field is the dominant driver of geomagnetic storms. Statistical studies have consistently shown that the independent correlation between solar wind density and geomagnetic storm intensity (via a proxy, such as the Dst index) is small. Modeling considerations predict a significant geomagnetic storm dependence on the plasma sheet density, which is indirectly connected to solar wind density. In this work, the solar wind density influence is quantified using two statistical measures: (1) data‐derived impulse response functions and (2) the relationship between the integrated value of Dst to the integrated value of the solar wind electric field during geomagnetic storm intervals. Results from both approaches indicate that the solar wind density modifies the geoefficiency or the ability of a given value of the solar wind electric field to create a Dst disturbance. The impulse response method also predicts that solar wind density explains the difference in geoefficiency, as opposed to the solar wind dynamic pressure. Although the geoefficiency effect is large, its influence is shown to be small when only large storms are considered because large storms typically have large density.