bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of alkali, silicate, and sulfate content of carbonated concrete pore solution on mild steel corrosion behavior
Authors: Huet B. , L'Hostis V. , Tricheux L. , Idrissi H. 
Published: May 2009

AbstractThe increase in the rebar corrosion rate due to the concrete carbonation is the major cause of reinforced concrete degradation. The aim of this study was to investigate the corrosion behavior of mild steel rebars in simulated carbonated concrete solution. For this purpose, thermodynamic calculations, electrochemical techniques, gravimetric measurements, and surface analyses were used. Thermodynamic investigations of the nature of the interstitial solution provides an estimation of the influence of sulfate (${\rm SO}_4^{2 - }$) and alkali (Na+, K+) content on carbonate alkalinity of the CO2/H2O open system (pCO2 = 0.3 mbar). In this system, calcium‐silicate hydrates (C–S–H) remain thermodynamically unstable and amorphous silica controls silicate aqueous content at 100 ppm. Electrochemical results highlight a decrease in the corrosion rate with increasing carbonate alkalinity and the introduction of silicate. The introduction of sulfate at fixed carbonate alkalinity shows a dual effect: at high carbonate alkalinity, the corrosion rate is increased whereas at low carbonate alkalinity, corrosion rate is decreased. Those results are supported by surface analysis. Authors conclude that silicate and sulfate release from cement hydrates and fixation of alkali on carbonated hydrates are key parameters to estimate mild steel corrosion in carbonated concrete.
PMMA Brushes Prepared in an Ionic Liquid
Authors: Nett Sebastian K. , Kircher Gunnar , Gutmann Jochen S. 
Published: May 2009

AbstractIn this report, we show the synthesis of polymethylmethacrylate (PMMA) brushes in the room temperature ionic liquid (IL) 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([Bmim][PF6]). The brushes were prepared on functionalized silicon by atom transfer radical polymerization (ATRP). Kinetic study of the ATRP process identified linear and dense brush growth up to thicknesses of 8.3 nm. We used the negligible vapor pressure of the IL as an advantage to prepare polymer brush coatings not only on substrates immersed in the reaction solution, but also in the confined geometry of a “micro” droplet. The living character of the ATRP synthesis supported this method because sequential addition of MMA to the microdroplet increased the brush thickness.magnified image
Synthesis and Properties of Oligophenylene‐Layered Polymers
Authors: Morisaki Yasuhiro , Imoto Hiroaki , Miyake Junpei , Chujo Yoshiki 
Published: May 2009

AbstractWe report syntheses of phenylene‐, biphenylene‐, and terphenylene‐layered polymers with a xanthene scaffold by the modified Suzuki‐Miyaura coupling reaction. Their optical properties were studied in detail. The polymer end‐capped by nitrobenzene units, which act as fluorescence quenchers, exhibited the photo‐excited energy transfer from the layered oligophenylenes to the terminal units.magnified image
Homocysteine and cognitive impairment in Parkinson's disease: A biochemical, neuroimaging, and genetic study
Authors: Rodriguez‐Oroz Maria C. , Lage Pablo Martínez , Sanchez‐Mut Jose , Lamet Isabel , Pagonabarraga Javier , Toledo Jon B. , García‐Garcia David , Clavero Pedro , Samaranch Lluis , Irurzun Cecilia , Matsubara Juan M. , Irigoien Jaione , Bescos Emilia , Kulisevsky Jaime , Pérez‐Tur Jordi , Obeso Jose A. 
Published: May 2009

AbstractThe role of the plasma level of homocysteine (Hcy), as a primary outcome, and the effect of silent cerebrovascular lesions and genetic variants related to Hcy metabolism, as secondary outcomes, in the cognitive decline and dementia in Parkinson's disease (PD) were studied. This case–control study focused on 89 PD patients of minimum 10 years of evolution and older than 60 years, who were neuropsychologically classified either as cognitively normal (n = 37), having mild cognitive impairment (Petersen criteria) (n = 22), or suffering from dementia (DSM‐IV) (n = 30), compared with cognitively normal age‐matched control subjects (n = 30). Plasma levels of Hcy, vitamins B12 and B6, folic acid, polymorphisms in genes related to Hcy metabolism (MTHFR, MTR, MTRR, and CBS) and silent cerebrovascular events were analyzed. Plasma levels of Hcy were increased in PD patients (P = 0.0001). There were no differences between the groups of patients. The brain vascular burden was similar among PD groups. There was no association between polymorphisms in the studied genes and the Hcy plasma levels or cognitive status in PD patients. We found no evidence for a direct relationship between Hcy plasma levels and cognitive impairment and dementia in PD. No indirect effect through cerebrovascular disease or genetic background was found either. © 2009 Movement Disorder Society
Repeatable battery for assessment of neuropsychological status in early Parkinson's disease
Authors: Yang Chengwu , Garrett‐Mayer Elizabeth , Schneider Jay S. , Gollomp Stephen M. , Tilley Barbara C. 
Published: May 2009

AbstractAdequate reliability and valid factor structure are prerequisites for appropriate use of a measure in a population. Although the Repeatable Battery for Assessment of Neuropsychological Status (RBANS) has been used to examine cognition in Parkinson's disease (PD), its reliability and factor structure have not been examined in this population. This study examined the reliability and factor structure of the RBANS in participants with de novo PD recruited for two NIH Exploratory Trials in Parkinson's Disease (NET‐PD), using Cronbach's α and factor analysis. Confirmatory factor analysis (CFA) was implemented on the factor structure proposed in the RBANS manual, and exploratory factor analysis (EFA) was conducted to identify a valid factor structure given the proposed one was not supported. The RBANS exhibited poor reliability in participants with NET‐PD. Cronbach's α ranged from 0.03 to 0.74 for the five domains and the full scale. CFA results indicated that the proposed factor structure in the RBANS manual was not supported in this sample. EFA identified a two‐factor structure for six of the 12 RBANS items. Six items were eliminated due to low correlation with other items or severe ceiling effects. This new factor structure was validated by another CFA. The two domains have fair reliability. Cronbach's α ranged from 0.65 to 0.74 for the two factors in the two datasets. These results suggest that the current RBANS domain and total scores may not provide valid measurement of the neuropsychological status for patients with early PD. © 2009 Movement Disorder Society
Validation of the questionnaire for impulsive‐compulsive disorders in Parkinson's disease
Authors: Weintraub Daniel , Hoops Staci , Shea Judy A. , Lyons Kelly E. , Pahwa Rajesh , Driver‐Dunckley Erika D. , Adler Charles H. , Potenza Marc N. , Miyasaki Janis , Siderowf Andrew D. , Duda John E. , Hurtig Howard I. , Colcher Amy , Horn Stacy S. , Stern Matthew B. , Voon Valerie 
Published: May 2009

AbstractAs no comprehensive assessment instrument for impulse control disorders (ICDs) in Parkinson's disease (PD) exists, the aim of this study was to design and assess the psychometric properties of a self‐administered screening questionnaire for ICDs and other compulsive behaviors in PD. The Questionnaire for Impulsive‐Compulsive Disorders in Parkinson's Disease (QUIP) has 3 sections: Section 1 assesses four ICDs (involving gambling, sexual, buying, and eating behaviors), Section 2 other compulsive behaviors (punding, hobbyism, and walkabout), and Section 3 compulsive medication use. For validation, a convenience sample of 157 PD patients at 4 movement disorders centers first completed the QUIP, and then was administered a diagnostic interview by a trained rater blinded to the QUIP results. A shortened instrument (QUIP‐S) was then explored. The discriminant validity of the QUIP was high for each disorder or behavior (receiver operating characteristic area under the curve [ROC AUC]: gambling = 0.95, sexual behavior = 0.97, buying = 0.87, eating = 0.88, punding = 0.78, hobbyism = 0.93, walkabout = 0.79). On post hoc analysis, the QUIP‐S ICD section had similar properties (ROC AUC: gambling = 0.95, sexual behavior = 0.96, buying = 0.87, eating = 0.88). When disorders/behaviors were combined, the sensitivity of the QUIP and QUIP‐S to detect an individual with any disorder was 96 and 94%, respectively. Scores on the QUIP appear to be valid as a self‐assessment screening instrument for a range of ICDs and other compulsive behaviors that occur in PD, and a shortened version may perform as well as the full version. A positive screen should be followed by a comprehensive, clinical interview to determine the range and severity of symptoms, as well as need for clinical management. © 2009 Movement Disorder Society
The spinning, structure, and properties of cellulose/chitin blend filaments through HWM method
Authors: He Chunju , Ma Bomou 
Published: May 2009

AbstractThe aim of this paper is the preparation and characterization of cellulose/chitin blend filaments over the experimental blend ratio scope i.e., 2.89 and 6.46% (w/w) chitin content through high wet modulus (HWM) procedure. The spinnability of the invested solutions was found to vary in the following order: chitin < cellulose < 9.5:0.5 blend < 9:1 blend < 8:2 blend < 5:5 blend (9:1 means the mass ratio of cellulose to chitin, so does 9.5:0.5, 8:2, and 5:5). The cross‐section of the blend filaments is of chrysanthemum shape. It was shown through the SEM photographs that there existed grooves on the surface of filaments, which became coarse with increase in chitin content. Based on the data from X‐ray, sonic velocity, intensity, and hygroscopicity, it is concluded that the degree of crystallinity, dry and wet intensity modulus, degree of orientation, and regain rate of the filaments decreased with increase in chitin content in the experiment scope. The mechanical properties of the blend filaments are much higher than those of Crabyon fiber and normal viscose filaments, which proves that the HWM method is an efficient way of preparing cellulose/chitin blend filaments with satisfactory mechanical properties and processing property. The blend filaments prepared have an effective biostatic effect on Staphylococcus aureus, Escherchia coli, and Corinebaterium michiganence according to different testing standards. Copyright © 2009 John Wiley & Sons, Ltd.
N‐terminal strands of filamin Ig domains act as a conformational switch under biological forces
Authors: Kesner Barry A. , Ding Feng , Temple Brenda R. , Dokholyan Nikolay V. 
Published: May 2009

AbstractConformational changes of filamin A under stress have been postulated to play crucial roles in signaling pathways of cell responses. Direct observation of conformational changes under stress is beyond the resolution of current experimental techniques. On the other hand, computational studies are mainly limited to either traditional molecular dynamics simulations of short durations and high forces or simulations of simplified models. Here we perform all‐atom discrete molecular dynamics (DMD) simulations to study thermally and force‐induced unfolding of filamin A. The high conformational sampling efficiency of DMD allows us to observe force‐induced unfolding of filamin A Ig domains under physiological forces. The computationally identified critical unfolding forces agree well with experimental measurements. Despite a large heterogeneity in the population of force‐induced intermediate states, we find a common initial unfolding intermediate in all the Ig domains of filamin, where the N‐terminal strand unfolds. We also study the thermal unfolding of several filamin Ig‐like domains. We find that thermally induced unfolding features an early‐stage intermediate state similar to the one observed in force‐induced unfolding and characterized by the N‐terminal strand being unfurled. We propose that the N‐terminal strand may act as a conformational switch that unfolds under physiological forces leading to exposure of cryptic binding sites, removal of native binding sites, and modulating the quaternary structure of domains. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Effective approach for calculations of absolute stability of proteins using focused dielectric constants
Authors: Vicatos Spyridon , Roca Maite , Warshel Arieh 
Published: May 2009

AbstractThe ability to predict the absolute stability of proteins based on their corresponding sequence and structure is a problem of great fundamental and practical importance. In this work, we report an extensive, refinement and validation of our recent approach (Roca et al., FEBS Lett 2007;581:2065–2071) for predicting absolute values of protein stability ΔGfold. This approach employs the semimacroscopic protein dipole Langevin dipole method in its linear response approximation version (PDLD/S‐LRA) while using the best fitted values of the dielectric constants ε′p and ε′eff for the self energy and charge–charge interactions, respectively. The method is validated on a diverse set of 45 proteins. It is found that the best fitted values of both dielectric constants are around 40. However, the self energy of internal residues and the charge–charge interactions of Lys have to be treated with care, using a somewhat lower values of ε′p and ε′eff. The predictions of ΔGfold reported here, have an average error of only 1.8 kcal/mole compared to the observed values, making our method very promising for estimating protein stability. It also provides valuable insight into the complex electrostatic phenomena taking place in folded proteins. Proteins 2009. © 2009 Wiley‐Liss, Inc.
Household diversity and migration in mid‐life: understanding residential mobility among 45–64 year olds in Melbourne, Australia
Authors: Wulff Maryann , Champion Anthony , Lobo Michele 
Published: May 2009

AbstractThis paper focuses on the residential mobility of middle‐aged persons, not yet retired, an understudied cohort in mobility research. From the 1950s to the 1980s, mobility studies pointed to mid‐life as a settled stage in terms of family, work and housing. Recent demographic and social changes, however, have led to these years being typified by a wide gamut of living arrangements that have complicated decisions about, and patterns of, residential mobility. Using the life‐course perspective, this paper suggests that the transition to ‘empty nester’ status will heighten mobility among this group of middle‐aged persons relative to their counterparts in other living arrangements. The analysis uses a customised migration matrix from the Australian 2006 Census and identifies segments of 45–64 year olds most likely to have changed address since the previous census in 2001. CHAID statistical method partitioned the 45–64 year old population in Melbourne, Australia, into eight statistically significant segments based on life‐course factors and mobility levels. Younger (45–54 years) mid‐life empty‐nesters changed residence at 1.4 times the mobility rate of all mid‐life persons. For couples in this age group, empty nest status conferred a 13 percentage point ‘mobility premium’ compared with couples that still had children at home. The results contribute to a better understanding of housing consumption among mid‐life households and broader debates on access to affordable housing and processes of urban growth. Copyright © 2009 John Wiley & Sons, Ltd.
Variable range hopping in oxygen‐exposed single‐wall carbon nanotube networks [Phys. Status Solidi A 205, No. 6, 1394–1398 (2008)]
Authors: Morgan C. , Alemipour Z. , Baxendale M. 
Published: May 2009

AbstractCorrected values for the coefficients G0 and T0 in Table 2 as well as the corrected value for the parameter T0 in Eq. (3) are given for the paper by Morgan et al. [Phys. Status Solidi A 205, No. 6, 1394–1398 (2008)]. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coupled magnetic plasmons in metamaterials
Authors: Liu H. , Liu Y. M. , Li T. , Wang S. M. , Zhu S. N. , Zhang X. 
Published: May 2009

AbstractMagnetic metamaterials consist of magnetic resonators smaller in size than their excitation wavelengths. Their unique electromagnetic properties were characterized by the effective media theory at the early stage. However, the effective media model does not take into account the interactions between magnetic elements; thus, the effective properties of bulk metamaterials are the result of the “averaged effect” of many uncoupled resonators. In recent years, it has been shown that the interaction between magnetic resonators could lead to some novel phenomena and interesting applications that do not exist in conventional uncoupled metamaterials. In this paper, we will give a review of recent developments in magnetic plasmonics arising from the coupling effect in metamaterials. For the system composed of several identical magnetic resonators, the coupling between these units produces multiple discrete resonance modes due to hybridization. In the case of a system comprising an infinite number of magnetic elements, these multiple discrete resonances can be extended to form a continuous frequency band by strong coupling. This kind of broadband and tunable magnetic metamaterial may have interesting applications. Many novel metamaterials and nanophotonic devices could be developed from coupled resonator systems in the future. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polonium bulk and surface vibrational dynamics
Authors: Khater Antoine , Tigrine Rachid , Bourahla Boualem 
Published: May 2009

AbstractCalculations are presented for the bulk phonons and for surface Rayleigh phonons and resonances for Polonium, the only element known to form in the simple cubic lattice. The static stability of this lattice has been confirmed recently by ab initio simulations which yield two bulk elastic constants, c11 and c12. Constitutive equations are derived for the isotropic cubic lattice based upon the Fuchs's method. This permits effectively a numerical evaluation of central potential force constants for Polonium from the ab initio results. Numerical calculations are then made for the material vibration dynamics in the force constant model with the use of the matching method. The numerical applications yield for Polonium the bulk phonon branches along [100], [110], and [111], and the Rayleigh phonons and surface resonances along the [010] direction in an unreconstructed (001) surface. The local vibration densities of states are calculated for bulk and surface sites for this element. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of hydrologic and geomorphic changes affecting a shrinking mire
Authors: Nakayama Tadanobu 
Published: May 2009

AbstractThe Kushiro Mire in subarctic Japan has significantly reduced in size because of the complex interaction of many processes, including snowmelt runoff, sediment transport and vegetation dynamics. This study uses a coupled integrated catchment‐based eco‐hydrology model with a mass transport process (NICE‐MASS) to investigate the influence of hydrologic and geomorphic changes on the Kushiro Mire. Coefficients of the sediment‐rating curve in the snowmelt runoff are very different from those in the snow‐free period. This empirical relation shall underestimate the observed suspended sediment (SS) concentration in the snowmelt period, indicating a difference in runoff mechanisms between the two periods and the necessity of a process‐based model. The simulation model reproduced well the spatial distribution of elevation aggradations by sediment deposits from rivers flowing into the mire. NICE‐MASS clarified that river channelization works carried out in the past resulted in groundwater degradation and drying phenomenon in the downstream area because of increased sedimentation and a decrease of seepage infiltration from the river to the aquifer. It is assumed that these hydrologic and geomorphic changes are closely related to the invasion of alder (Alnus japonica) into the mire. The occupation rate of alder is positively correlated with groundwater degradation relative to the ground surface. The model simulation derived by addition of this limiting factors related to submerged depth is important for prediction of vegetation succession when devising future policies for restoration of meandering river channels. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis of cobalt oxide aerogels and nanocomposite systems containing single‐walled carbon nanotubes
Authors: Gill Simerjeet K. , Shobe Andrew M. , Hope‐Weeks Louisa J. 
Published: May 2009

AbstractThe synthesis and characterization of porous nanostructured cobalt oxide (Co3O4) aerogels using epoxide addition method is described. Cobalt‐containing monoliths were obtained by sol–gel processing of an alcoholic cobalt chloride solution with propylene oxide as the gelation agent. The alcogels were dried by supercritical CO2 fluid extraction to obtain the highly porous amorphous cobalt (II) aerogels. To enhance and control the structural properties of the aerogels, single‐walled carbon nanotubes (SWCNT) were incorporated into the cobalt (II) aerogel network to form a homogenous composite material. The resulting materials were characterized using powder X‐ray diffraction and nitrogen adsorption/desorption analysis. The detailed microstructure of aerogel networks was investigated using scanning and transmission electron microscopy, which showed significant structural changes induced by the incorporation of SWCNT to the cobalt aerogel. Annealing of the aerogel materials at 600°C yields a highly crystalline well‐faceted Co3O4 network SCANNING 31: 132–138, 2009. © 2009 Wiley Periodicals, Inc.
Portfolio selection models: a review and new directions
Authors: Roman Diana , Mitra Gautam 
Published: May 2009

AbstractModern Portfolio Theory (MPT) is based upon the classical Markowitz model which uses variance as a risk measure. A generalization of this approach leads to mean‐risk models, in which a return distribution is characterized by the expected value of return (desired to be large) and a “risk” value (desired to be kept small). Portfolio choice is made by solving an optimization problem, in which the portfolio risk is minimized and a desired level of expected return is specified as a constraint. The need to penalize different undesirable aspects of the return distribution led to the proposal of alternative risk measures, notably those penalizing only the downside part (adverse) and not the upside (potential). The downside risk considerations constitute the basis of the Post Modern Portfolio Theory (PMPT). Examples of such risk measures are lower partial moments, Value‐at‐Risk (VaR) and Conditional Value‐at‐Risk (CVaR). We revisit these risk measures and the resulting mean‐risk models. We discuss alternative models for portfolio selection, their choice criteria and the evolution of MPT to PMPT which incorporates: utility maximization and stochastic dominance. Copyright © 2009 Wilmott Magazine Ltd
Smile dynamics: a theory of the implied leverage effect
Authors: Ciliberti Stefano , Bouchaud Jean‐Philippe , Potters Marc 
Published: May 2009

AbstractWe study in details the skew of stock option smiles, which is induced by the so‐called leverage effect on the underlying B i.e. the correlation between past returns and future square returns. This naturally explains the anomalous dependence of the skew as a function of maturity of the option. The market cap dependence of the leverage effect is analyzed using a one‐factor model. We show how this leverage correlation gives rise to a non‐trivial smile dynamics, which turns out to be intermediate between the “sticky strike” and the “sticky delta” rules. Finally, we compare our result with stock option data, and find that option markets overestimate the leverage effect by a large factor, in particular for long dated options. Copyright © 2009 Wilmott Magazine Ltd