bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of Chiral Environments by a Mechanical Induced Vortex Flow
Authors: Okano Kunihiko , Yamashita Takashi
Published: April 2012

A chiral molecule absorbs preferentially right‐ or left‐handed circularly polarized light in a circular dichroism (CD) measurement. Usually, the chirality of individual molecules is regarded as the origin of the CD signals. However, recently, several reports have suggested that the vortex flow of a solution of an achiral molecule gives rise to a CD signal, which is dependent on the stirring direction. This article introduces types of molecular architecture and material designs that show stir‐induced chirality. We also discuss the effects of the molecular structure and alignment in vortex flows on this phenomena, reviewing the related issues.
A Molecular Dynamics Study of Viscosity in Ionic Liquids Directed by Quantitative Structure–Property Relationships
Authors: Butler Simon N. , Müller‐Plathe Florian
Published: April 2012

A computational study into the molecular origin of viscosity in ionic liquids via a combined quantitative structure–property relationship (QSPR) and molecular dynamics (MD) approach is presented. QSPR models are developed for ionic liquids containing the bis[(trifluoromethyl)sulfonyl]imide (TFSI) anion using literature data. The best models thus developed are used to identify persistently well‐correlating molecular descriptors for further investigation by MD. By modifying the force field of a simple ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate [bmim][PF6], the efficacy of the charged partial surface area (CPSA) descriptor is examined. Finally, by building QSPR models from the MD data and calculations derived from the CPSA descriptor, potential routes for improved prediction of ionic liquid viscosity are proposed.
An ATR‐FTIR Study on the Effect of Molecular Structural Variations on the CO2 Absorption Characteristics of Heterocyclic Amines, Part II
Authors: Robinson Kelly , McCluskey Adam , Attalla Moetaz I.
Published: April 2012

This paper reports on an ATR‐FTIR spectroscopic investigation of the CO2 absorption characteristics of a series of heterocyclic diamines: hexahydropyrimidine (HHPY), 2‐methyl and 2,2‐dimethylhexahydropyrimidine (MHHPY and DMHHPY), hexahydropyridazine (HHPZ), piperazine (PZ) and 2,5‐ and 2,6‐dimethylpiperazine (2,6‐DMPZ and 2,5‐DMPZ). By using in situ ATR‐FTIR the structure–activity relationship of the reaction between heterocyclic diamines and CO2 is probed. PZ forms a hydrolysis‐resistant carbamate derivative, while HHPY forms a more labile carbamate species with increased susceptibility to hydrolysis, particularly at higher CO2 loadings (>0.5 mol CO2/mol amine). HHPY exhibits similar reactivity toward CO2 to PZ, but with improved aqueous solubility. The α‐methyl‐substituted MHHPY favours HCO3− formation, but MHHPY exhibits comparable CO2 absorption capacity to conventional amines MEA and DEA. MHHPY show improved reactivity compared to the conventional α‐methyl‐ substituted primary amine 2‐amino‐2‐methyl‐1‐propanol. DMHHPY is representative of blended amine systems, and its reactivity highlights the advantages of such systems. HHPZ is relatively unreactive towards CO2. The CO2 absorption capacity CA (mol CO2/mol amine) and initial rates of absorption RIA (mol CO2/mol amine min−1) for each reactive diamine are determined: PZ: CA=0.92, RIA=0.045; 2,6‐DMPZ: CA=0.86, RIA=0.025; 2,5‐DMPZ: CA=0.88, RIA=0.018; HHPY: CA=0.85, RIA=0.032; MHHPY: CA=0.86, RIA=0.018; DMHHPY: CA=1.1, RIA=0.032; and HHPZ: no reaction. Calculations at the B3LYP/6‐31+G** and MP2/6‐31+G** calculations show that the substitution patterns of the heterocyclic diamines affect carbamate stability, which influences hydrolysis rates.
Catalytic Conversion of Inulin and Fructose into 5‐Hydroxymethylfurfural by Lignosulfonic Acid in Ionic Liquids
Authors: Xie Haibo , Zhao Zongbao K. , Wang Qian
Published: April 2012

In this work, we found that lignosulfonic acid (LS), which is a waste byproduct from the paper industry, in ionic liquids (ILs) can catalyze the dehydration of fructose and inulin into 5‐hydroxymethylfurfural (HMF) efficiently, which is a promising potential substitute for petroleum‐based building blocks. The effects of reaction time, temperature, catalyst loading, and reusability of the catalytic system were studied. It was found that a 94.3 % yield of HMF could be achieved in only 10 min at 100 °C under mild conditions. The reusability study of the LS–IL catalytic system after removal of HMF by ethyl acetate extraction demonstrated that the catalytic activity decreased from 77.4 to 62.9 % after five cycles and the catalytic activity could be recovered after simply removing the accumulated humins by filtration after adding ethanol to the LS–ILs. The integrated utilization of a biorenewable feedstock, catalyst, and ILs is an example of an ideal green chemical process.
Lignin Model Compounds as Bio‐Based Reactive Diluents for Liquid Molding Resins
Authors: Stanzione Joseph F. , Sadler Joshua M. , La Scala John J. , Wool Richard P.
Published: April 2012

Lignin is a copious paper and pulping waste product that has the potential to yield valuable, low molecular weight, single aromatic chemicals when strategically depolymerized. The single aromatic lignin model compounds, vanillin, guaiacol, and eugenol, were methacrylated by esterification with methacrylic anhydride and a catalytic amount of 4‐dimethylaminopyridine. Methacrylated guaiacol (MG) and methacrylated eugenol (ME) exhibited low viscosities at room temperature (MG: 17 cP and ME: 28 cP). When used as reactive diluents in vinyl ester resins, they produced resin viscosities higher than that of vinyl ester–styrene blends. The relative volatilities of MG (1.05 wt % loss in 18 h) and ME (0.96 wt % loss in 18 h) measured by means of thermogravimetric analysis (TGA) were considerably lower than that of styrene (93.7 wt % loss in 3 h) indicating the potential of these chemicals to be environmentally friendly reactive diluents. Bulk polymerization of MG and ME generated homopolymers with glass transition temperatures (Tgs) of 92 and 103 °C, respectively. Blends of a standard vinyl ester resin with MG and ME (50 wt % reactive diluent) produced thermosets with Tgs of 127 and 153 °C, respectively, which are comparable to vinyl ester–styrene resins, thus demonstrating the ability of MG and ME to completely replace styrene as reactive diluents in liquid molding resins without sacrificing cured‐resin thermal performance.
Energy Efficiency Enhancement of Ethanol Electrooxidation on Pd–CeO2/C in Passive and Active Polymer Electrolyte‐Membrane Fuel Cells
Authors: Bambagioni Valentina , Bianchini Claudio , Chen Yanxin , Filippi Jonathan , Fornasiero Paolo , Innocenti Massimo , Lavacchi Alessandro , Marchionni Andrea , Oberhauser Werner , Vizza Francesco
Published: April 2012

Pd nanoparticles have been generated by performing an electroless procedure on a mixed ceria (CeO2)/carbon black (Vulcan XC‐72) support. The resulting material, Pd–CeO2/C, has been characterized by means of transmission electron microscopy (TEM), inductively coupled plasma atomic emission spectroscopy (ICP–AES), and X‐ray diffraction (XRD) techniques. Electrodes coated with Pd–CeO2/C have been scrutinized for the oxidation of ethanol in alkaline media in half cells as well as in passive and active direct ethanol fuel cells (DEFCs). Membrane electrode assemblies have been fabricated using Pd–CeO2/C anodes, proprietary FeCo cathodes, and Tokuyama anion‐exchange membranes. The monoplanar passive and active DEFCs have been fed with aqueous solutions of 10 wt % ethanol and 2 M KOH, supplying power densities as high as 66 mW cm−2 at 25 °C and 140 mW cm−2 at 80 °C. A comparison with a standard anode electrocatalyst containing Pd nanoparticles (Pd/C) has shown that, at even metal loading and experimental conditions, the energy released by the cells with the Pd–CeO2/C electrocatalyst is twice as much as that supplied by the cells with the Pd/C electrocatalyst. A cyclic voltammetry study has shown that the co‐support ceria contributes to the remarkable decrease of the onset oxidation potential of ethanol. It is proposed that ceria promotes the formation at low potentials of species adsorbed on Pd, PdI‐OHads, that are responsible for ethanol oxidation.
A biomimetic potentiometric sensor based on molecularly imprinted polymer for the determination of memantine in tablets
Authors: Arvand Majid , Samie Hedyeh Asadi
Published: April 2012

Memantine hydrochloride is one of the first novel class medications for treatment of Alzheimer's disease. In this work, a biomimetic potentiometric sensor, based on a non‐covalent imprinted polymer, was fabricated for the recognition and determination of memantine in pure drug and tablet pharmaceutical form. The molecularly imprinted polymer was synthesized by precipitation polymerization, using memantine hydrochloride as a template molecule, methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a cross‐linking agent. The sensor was developed by dispersing the memantine imprinted polymer particles in dibutyl sebacate plasticizer and embedding in poly(vinyl chloride) matrix. The wide linear range (10−5−10−1 M), with a near Nernstian response of 57.4 mV/decade, a limit of detection 6.0 × 10−6 M, fast response time (~15 s) and a satisfactory long‐term stability (4 months) are characterizations of the proposed sensor. The sensor showed a high selectivity and a sensitive response to the template in aqueous system. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode. It was used as indicator electrode in potentiometric determination of memantine in pharmaceutical formulations. Copyright © 2012 John Wiley & Sons, Ltd.
Validity of the night eating questionnaire in children
Authors: Gallant Annette R. , Lundgren Jennifer , Allison Kelly , Stunkard Albert J. , Lambert Marie , O'Loughlin Jennifer , Lemieux Simone , Tremblay Angelo , Drapeau Vicky
Published: April 2012

Objective:

To measure the construct validity of the Night Eating Questionnaire (NEQ) in children against a parent report of child night eating syndrome (NES) symptoms (NEQ report) and a 3‐day dietary recall.

Method:

NEQ of 304 children from the QUALITY (QUébec Adipose and Lifestyle InvesTigation in Youth) cohort were compared to a parent report and 3‐day dietary recall.

Results:

Child NEQ scores were related to the parent NEQ report (ρ = 0.30 p < 0.0001) yet there were inconsistencies between responses concerning sleep troubles. Total child NEQ scores, but not parent NEQ report scores, were associated with dietary manifestations of NES such as increased evening (ρ = 0.20, p < .001) and reduced morning intake (ρ= −0.12, p < .05).

Discussion:

The NEQ score is related to eating patterns of NES in children and is more informative than a parent report, specifically when used in conjunction with dietary recall. © 2012 by Wiley Periodicals, Inc. (Int J Eat Disord 2012;45:861–865)
Adsorption characteristics of [Fe(III)–EDTA]− on granular activated carbon from aqueous solutions
Authors: Yang Xiao‐Juan , Long Xiang‐Li , Yuan Wei‐Kang
Published: April 2012

In this study, the adsorption of [Fe(III)–EDTA]− on coconut‐activated carbon from aqueous solutions has been studied in a batch stirred cell. Experiments have been carried out to investigate the effects of temperature, [Fe(III)–EDTA]− concentration, pH, and activated carbon mass on [Fe(III)–EDTA]− adsorption. The experimental results manifest that high temperature is favorable to the adsorption of [Fe(III)–EDTA]− on the activated carbon. The [Fe(III)–EDTA]− adsorption on activated carbon increases with its concentration in the aqueous solutions. However, the [Fe(III)–EDTA]− adsorption on activated carbon decreases as the pH rises. The [Fe(III)–EDTA]− adsorption on per gram of activated carbon decreases as the activated carbon mass increases. The kinetic study shows that [Fe(III)–EDTA]− adsorption on the activated carbon is in good compliance with the pseudo‐second‐order kinetic model. The Langmuir and Freundlich equilibrium isotherm models are found to provide a good fitting of the adsorption data. Thermodynamic parameters such as Ea, ΔG0, ΔH0, and ΔS0 for adsorption reaction are estimated. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 470–479, 2013
Natural gas—producers: Jurisdictions vary greatly on when natural gas becomes marketable
Authors: Campbell Michael
Published: April 2012

In recent years, natural gas producers throughout the United States have been subjected to lawsuits by royalty and overriding royalty owners asserting that producers have underpaid them royalty by deducting from royalty payments their share of costs associated with postproduction services (i.e., gathering, dehydrating, treating/processing, and compressing gas between the wellhead and plant tailgates). Such claims are generically referenced as assertions for application of the so‐called marketable condition rule.
Exploring Paleogeographic Conditions at TwoPaleolithic Sites inNavarino, SouthwestGreece, Dated by Optically Stimulated Luminescence
Authors: Athanassas Constantin , Bassiakos Yannis , Wagner Günther A. , Timpson Michael E.
Published: April 2012

In this paper, we employed optically stimulated luminescence (OSL) dating of sediments from two archaeological sites located inNavarino,Messenia, southwesternGreece, to deduce a chronology for the archaeological sites. Archaeological surveys identified twoPaleolithic sites on fossilized coastal dunes. Chipped stone tool assemblages were identified eroding out of paleosols developed in the dunes. The assemblage from one site lacked distinct typological features and hence it was difficult to assign to a chronological period. The lithic assemblage from the other site contained artifacts that typologically can be assigned to theLevallois‐Mousterian. Previous efforts to date the artifact‐bearing sediments at these sites were unsuccessful. Using newerOSLdating methods (i.e., the Single‐Aliquot‐Regenerated Dose protocol and thermally transferred‐OSL[TT‐OSL]), we attempted to construct a chronological framework forLatePleistocene human activity in the southwestPeloponnese. The revisedOSLchronology for the first site is 28 ± 5 ka, while a luminescence age of 8 ± 1 ka for the second site only represents a later deflation event. Within the framework ofQuaternary environmental change, the location ofPaleolithic sites relative to the coast would have changed during the course of thePleistocene. As a result,Paleolithic exploitation strategies would have been strongly influenced by the changing coastal geomorphology, encouraging hominids to adapt to new distributions of resources.OSLdating of the archaeological sites allowed us to connect traces of hominid activity with climatic stadials/interstadials of the laterPleistocene derived from existing relative sea‐level curves. Ultimately, these data permitted the reconstruction of regionalLatePleistocene paleogeography. © 2012 Wiley Periodicals, Inc.
A Better Coefficient of Determination for Genetic Profile Analysis
Authors: Lee Sang Hong , Goddard Michael E , Wray Naomi R , Visscher Peter M
Published: April 2012

Genome‐wide association studies have facilitated the construction of risk predictors for disease from multiple Single Nucleotide Polymorphism markers. The ability of such “genetic profiles” to predict outcome is usually quantified in an independent data set. Coefficients of determination (R2) have been a useful measure to quantify the goodness‐of‐fit of the genetic profile. Various pseudo‐R2 measures for binary responses have been proposed. However, there is no standard or consensus measure because the concept of residual variance is not easily defined on the observed probability scale. Unlike other nongenetic predictors such as environmental exposure, there is prior information on genetic predictors because for most traits there are estimates of the proportion of variation in risk in the population due to all genetic factors, the heritability. It is this useful ability to benchmark that makes the choice of a measure of goodness‐of‐fit in genetic profiling different from that of nongenetic predictors. In this study, we use a liability threshold model to establish the relationship between the observed probability scale and underlying liability scale in measuring R2 for binary responses. We show that currently used R2 measures are difficult to interpret, biased by ascertainment, and not comparable to heritability. We suggest a novel and globally standard measure of R2 that is interpretable on the liability scale. Furthermore, even when using ascertained case‐control studies that are typical in human disease studies, we can obtain an R2 measure on the liability scale that can be compared directly to heritability.
Comparative study of robotic versus endoscopic thyroidectomy by a gasless unilateral axillo‐breast or axillary approach
Authors: Tae Kyung , Bae Ji Yong , Hyeok Jeong Jin , Rae Kim Kyung , Hwan Choi Woong , Hern Ahn You
Published: April 2012

Background

Robotic thyroidectomy and conventional endoscopic thyroidectomy have not been thoroughly compared. In this study, we compared the potential advantages of robotic versus endoscopic thyroidectomy.

Methods

We analyzed 218 consecutive patients who underwent endoscopic (105 cases) or robotic (113 cases) thyroidectomy using a gasless unilateral axillo‐breast or gasless unilateral axillary approach.

Results

Because of the dexterity of robotic instruments and the improved surgical view, it was subjectively easier and took less time to perform a complete total thyroidectomy and central compartment neck dissection in robotic thyroidectomy. In the case of unilateral lobectomy, endoscopic and robotic thyroidectomy had quite similar surgical outcomes. Cosmetic satisfaction was excellent in both groups.

Conclusion

In this series by a single surgeon, robotic thyroidectomy was superior to endoscopic thyroidectomy for performing total thyroidectomy and bilateral central compartment neck dissection. However, in terms of cost‐effectiveness, endoscopic thyroidectomy was comparable to robotic thyroidectomy in patients who undergo unilateral lobectomy. © 2012 Wiley Periodicals, Inc. Head Neck, 2013
EGFR activation is a potential determinant of primary resistance of hepatocellular carcinoma cells to sorafenib
Authors: Ezzoukhry Zakaria , Louandre Christophe , Trécherel Eric , Godin Corinne , Chauffert Bruno , Dupont Sébastien , Diouf Momar , Barbare Jean‐Claude , Mazière Jean‐Claude , Galmiche Antoine
Published: April 2012

Sorafenib is currently the medical treatment of reference for hepatocellular carcinoma (HCC), but it is not known whether sorafenib is equally active in all HCC. Here, our aim was to explore intrinsic differences in the response of HCC cells to sorafenib, to identify potential mechanisms leading to primary resistance to this treatment. We analyzed a panel of six human HCC cell lines and compared the activity of the main oncogenic kinase cascades, their clonogenic potential, proliferation and apoptosis upon exposure to sorafenib. We report that HCC cells present important differences in their response to sorafenib, and that some cell lines are more resistant to the actions of sorafenib than others. We identify the activated epidermal growth factor receptor (EGFR) as a parameter that promotes the resistance of HCC cells to sorafenib. In resistant cells, the efficacy of sorafenib was increased when EGFR was inhibited, as was demonstrated using two chemical inhibitors (erlotinib or gefitinib), a monoclonal antibody directed against EGFR (cetuximab), and RNA interference directed against EGFR. A combination of EGFR inhibitors and sorafenib affords a better control over HCC proliferation, most likely through an improved blockade of the RAF kinases. Our findings therefore confirm the importance of RAF kinases as therapeutic targets in HCC, and identify EGFR as a determinant of the sensitivity of HCC cells to sorafenib. Our findings bear possible implications for the improvement of the efficacy of sorafenib in HCC, and might be useful for the identification of predictive biomarkers in this context.
The PTSD Checklist—Civilian Version: Reliability, Validity, and Factor Structure in a Nonclinical Sample
Authors: Conybeare Daniel , Behar Evelyn , Solomon Ari , Newman Michelle G. , Borkovec T. D.
Published: April 2012

Objectives

We examined the reliability, validity, and factor structure of the posttraumatic stress diorder (PTSD) Checklist‐Civilian Version (PCL‐C; Blanchard, Jones‐Alexander, Buckley, & Forneris, 1996) among unselected undergraduate students.

Participants

Participants were 471 undergraduate students at a large university in the Eastern United States and were not preselected based on trauma history or symptom severity.

Results

The PCL‐C demonstrated good internal consistency and retest reliability. Compared with alternative measures of PTSD, the PCL‐C showed favorable patterns of convergent and discriminant validity. In contrast to previous research using samples with known trauma exposure, we found support for both 1‐factor and 2‐factor models of PTSD symptoms.

Conclusions

Overall, the PCL‐C appears to be a valid and reliable measure of PTSD symptoms, even among nonclinical samples, and is superior to some alternative measures of PTSD. The factor structure among nonclinical samples may not reflect each of the PTSD symptom “clusters” (i.e., reexperiencing, avoidance/numbing, and hyperarousal). © 2012 Wiley Periodicals, Inc. J. Clin. Psychol. 00:1–15, 2012.
Measurement of distance with the nanoscale precise imaging by rapid beam oscillation method
Authors: Lanzano Luca , Gratton Enrico
Published: April 2012

We discuss here the principles of a novel optical method in which the scanning of a laser spot around a fluorescent object is used to determine its shape, orientation, and fluorophore distribution. The scanning pattern is adapted to the shape of the object according to a feedback principle based on intensity modulation measurements. The modulation of the intensity with respect to the angular coordinate is used to keep the orbit centered on the object. The modulation induced by rapid oscillations of the orbit radius is used to measure the local distance from the surface with nanometer precision. We provide a model to describe the fundamental relationship between modulation and distance and discuss the range of validity of several approximate expressions. According to this model, the distance can be measured with a precision dependent on the steepness of the point spread function and the total number of detected photons. To test our findings, we performed experiments with one or two channels on fluorescent spheres of known size and characterized the modulation function of our microscope setup. We conclude that the method can be used to measure distances in the range 10–200 nm between two surfaces labeled with two different probes. Microsc. Res. Tech. 75:1253–1264, 2012. © 2012 Wiley Periodicals, Inc.
Microscopic vision based on the adaptive positioning of the camera coordinate frame
Authors: Zhang Guangjun , Li Weixian , Wei Zhenzhong , Cao Zhipeng , Wang Yali
Published: April 2012

Microscopic vision measurement precision has been largely limited by inaccurately calibrated model parameters, because image plane is near parallel to reference plane in the narrow depth of field. This article proposes a method of precise microscopic vision measurement based on the adaptive positioning of the camera coordinate frame. The microscopic vision measurement movably attaches the origin of the camera coordinate frame along the optical axis. By finding the optimal position, the nonlinearity of the objective function in calibration optimization is decreased and the optimization sensitivity to initial values is reduced. Therefore, we obtain a high calibration precision and eventually ensure a high measurement precision. Mathematical simulations illustrate that the calibration precision of the proposed microscopic vision measurement model is higher than that of the conventional vision measurement model. The experiment shows that with magnification of 3.024×, the presented system achieves a precision of 0.12% based on the proposed microscopic vision measurement model, which is two times higher than the one based on the conventional vision measurement model. Microsc. Res. Tech. 75:1281–1291, 2012. © 2012 Wiley Periodicals, Inc.
Sequential differentiation of mesenchymal stem cells in an agarose scaffold promotes a physis‐like zonal alignment of chondrocytes
Authors: Schmitt Jacqueline Frida , Hua See Kwee , Zheng Yang , Po James Hui Hoi , Hin Lee Eng
Published: April 2012

Chondrocytes of the epiphyseal growth plate (physis) differentiate and mature in defined linear zones. The current study examines the differentiation of human bone marrow derived mesenchymal stem cells (hBMSCs) into zonal physeal cartilage. hBMSCs were embedded in an agarose scaffold with only the surface of the scaffold in direct contact with the culture medium. The cells were differentiated using a two‐step system involving the sequential addition of TGFβ followed by BMP2. The resultant samples displayed a heterogenic population of physis‐like collagen type 2 positive cells including proliferating chondrocytes and mature chondrocytes showing hypertrophy, expression of early bone markers and matrix mineralization. Histological analysis revealed a physis‐like linear zonal alignment of chondrocytes in varying stages of differentiation. The less mature chondrocytes were seen at the base of the construct while hypertrophic chondrocytes and matrix mineralization was observed closer to the surface of the construct. The described differentiation protocol using hBMSCs in an agarose scaffold can be used to study the factors and conditions that influence the differentiation, proliferation, maturation, and zonal alignment of physeal chondrocytes. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1753–1759, 2012
Epidemiology and risk factors for perioperative mortality after total hip and knee arthroplasty
Authors: Memtsoudis Stavros G. , Pumberger Matthias , Ma Yan , Chiu Ya‐Lin , Fritsch Gerhard , Gerner Peter , Poultsides Lazaros , Valle Alejandro Gonzalez Della
Published: April 2012

The perioperative mortality of total knee and hip arthroplasties (TKA, THA) remains a major concern among health care providers and their patients. The increase in utilization of TKA and THA makes it imperative to be aware of factors that are associated with this unfortunate event. Therefore we analyzed the Nationwide Inpatient Sample data from 1998 to 2008 and compared admissions with perioperative mortality to those that survived their hospitalization. An estimated total of 4,438,213 TKA and 2,182,121 THA procedures were performed in the United States between 1998 and 2008. The average mortality rate for TKA was 0.13% and 0.18% for THA, or 0.34 and 0.44 events per 1,000 inpatient days, respectively. Independent risk factors for in‐hospital mortality were advanced age, male gender, ethnic minority background, emergency admission as well as a number of comorbidities and complications. Furthermore, we demonstrated that the timing of death occurred earlier after TKA when compared to THA, with 50% of fatalities occurring by day 4 versus day 6 of the hospitalization, respectively. This study provides nationally representative information on risk factors for and timing of perioperative mortality after TKA and THA. Our data can be used to assess the risk for perioperative mortality and to develop targeted intervention to decrease such risk. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1811–1821, 2012
Development of a Neolithic pine tree‐ring chronology for northern Scotland
Authors: Moir Andy
Published: April 2012

The peatlands of northern Scotland (one of the largest and most intact areas of blanket bog in the world) contain a rare widespread horizon of subfossil pine in stratigraphic context. Eighteen bog pine from three new sites are incorporated into a mean Neolithic pine chronology now composed of subfossil pine from 12 sites, which is tree‐ring‐dated against Irish bog pine chronologies to span 3198–2757 BC. Germination and peaks of radial growth infer drier conditions between 3199 and 3130 BC. Dying‐off phases and depression of growth reflect a change to wetter conditions between 3023 and 3002 BC and a terminal decline of pine between 2809 and 2782 BC. The close synchronization of germination/die‐off phases and major ring‐width variations between sites across this region indicates that the environmental changes are probably triggered by climate change. Twenty‐four bog pine samples remain unmatched. Future multi‐discipline research into this important example of climatic change at the Neolithic/Bronze Age transition is recommended. Copyright © 2012 John Wiley & Sons, Ltd.
A linear sampling method for inverse problems of diffraction gratings of mixed type
Authors: Hu Guanghui , Qu Fenglong , Zhang Bo
Published: April 2012

This paper is concerned with the direct and inverse problem of scattering of a time‐harmonic wave by a Lipschitz diffraction grating of mixed type. The scattering problem is modeled by the mixed boundary value problem for the Helmholtz equation in the unbounded half‐plane domain above a periodic Lipschitz surface on which a mixed Dirichlet and impedance boundary condition is imposed. We first establish the well‐posedness of the direct problem, employing the variational method, and then extend Isakov's method to prove uniqueness in determining the Lipschitz diffraction grating profile by using point sources lying above the structure. Finally, we develop a periodic version of the linear sampling method to reconstruct the diffraction grating. In this case, the far field equation defined on the unit circle is replaced by a near field equation defined on a line above the surface, which is a linear integral equation of the first kind. Numerical results are also presented to illustrate the efficiency of the method in the case when the height of the unknown grating profile is not very large and the noise level of the near field measurements is not very high. Copyright © 2012 John Wiley & Sons, Ltd.
SPECIAL semi‐LASER with lipid artifact compensation for 1H MRS at 7 T
Authors: Fuchs Alexander , Luttje Mariska , Boesiger Peter , Henning Anke
Published: April 2012

The measurement of full metabolic profiles at ultrahigh fields including low concentrated or fast‐relaxing metabolites is usually achieved by applying short echo time sequences. One sequence beside stimulated echo acquisition mode that was proposed in this regard is spin echo full intensity‐acquired localized spectroscopy. Typical problems that are still persistent for spin echo full intensity‐acquired localized spectroscopy are B1 inhomogeneities especially for signal acquisition with surface coils and chemical shift displacement artifacts due to limited B1 amplitudes when using volume coils. In addition, strong lipid contaminations in the final spectrum can occur when only a limited number of outer volume suppression pulses is used. Therefore, an adiabatic short echo time (= 19 ms) spin echo full intensity‐acquired localized spectroscopy semilocalization by adiabatic selective refocusing sequence is presented that is less sensitive to strong B1 variations and that offers increased excitation and refocusing pulse bandwidths than regular spin echo full intensity acquired localized spectroscopy. Furthermore, the existence of the systematic lipid artifact is identified and linked to unfavorable effects due to the preinversion localization pulse. A method to control this artifact is presented and validated in both phantom and in vivo measurements. The viability of the proposed sequence was further assessed for in vivo measurements by scanning 17 volunteers using a surface coil and moreover acquiring additional volume coil measurements. The results show well‐suppressed lipid artifacts, good signal‐to‐noise ratio, and reproducible fitting results in accordance with other published studies. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
Test–retest reproducibility of a rapid method to measure brain oxygen metabolism
Authors: Liu Peiying , Xu Feng , Lu Hanzhang
Published: April 2012

Cerebral metabolic rate of oxygen (CMRO2) is an important index of tissue viability and brain function, but this parameter cannot yet be measured routinely on clinical scanners. Recently, a noninvasive technique was proposed which estimates global CMRO2 by concomitantly measuring oxygen‐extraction‐fraction using T2‐relaxation‐under‐spin‐tagging MRI and pulse oximetry, and cerebral‐blood‐flow using phase‐contrast MRI. This study sought to establish a standard acquisition procedure for this technique and to evaluate its test–retest reproducibility in healthy subjects. Each subject was examined in five sessions and each session included two measurements. Intrasession, intersession, and intersubject coefficients of variation for CMRO2 were found to be 3.84 ± 1.44% (N = 7, mean ± standard deviation), 6.59 ± 1.56%, and 8.80% respectively. These reproducibility values were comparable or slightly superior to 15O positron emission tomography (PET) results reported in the literature. It was also found that oxygen‐extraction‐fraction and cerebral‐blood‐flow tended to co‐vary across sessions (P = 0.002) and subjects (P = 0.01), and their coefficients of variation were greater than that of CMRO2. The simplicity and reliability features may afford this global CMRO2 technique great potential for immediate clinical applications. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
‘To Suddenly Have a Name for this Thing… Was Wonderful’: The Patient's Experience of Receiving a Diagnosis of Systemic Lupus Erythematosus
Authors: Waldron Nicola , Brown Sue J. , Hewlett Sarah , Elliott Barbara , McHugh Neil , McCabe Candy S.
Published: April 2012

Objectives

The aim of this study was to explore the patient's perception of receiving a diagnosis of systemic lupus erythematosus (lupus) and reports on their experience of the period between onset of symptoms and receiving a definitive diagnosis.

Methods

Focus groups were conducted in seven rheumatology centres. Forty‐three participants were purposively selected and data were subjected to thematic deductive analysis.

Results

Focus group data generated three major themes. ‘Diagnostic uncertainty and misdiagnosis’ describes the frustration for many of experiencing years of often debilitating symptoms that have gone unacknowledged by health professionals and misunderstood by themselves. Some experienced the trauma of being misdiagnosed, which impacted on how they adjusted to their final diagnosis of lupus. ‘Consequences of receiving a diagnosis’ highlights the feelings of relief for participants at finally having a diagnosis, despite its implications. However, the manner in which this knowledge was delivered was often inappropriate and unsupported, affecting how they adjusted to future management of their condition. ‘Impact on individuals' lives’ explores how many felt empowered by finally receiving recognition for their symptoms, but the diagnosis of a relatively unknown condition with often invisible symptoms impacted on the response and support they received from those around them.

Conclusion

It is essential health professionals have a greater understanding of the patient experience prior to receiving a diagnosis of lupus. The individual experience from symptom onset to diagnosis has a direct impact on the patient's subsequent acceptance of their diagnosis and response to management and therefore justifies the need for further research in this field. Copyright © 2012 John Wiley & Sons, Ltd.
On enrichment functions in the extended finite element method
Authors: Zhu Qi‐Zhi
Published: April 2012

This paper presents mathematical derivation of enrichment functions in the extended finite element method for numerical modeling of strong and weak discontinuities. The proposed approach consists in combining the level set method with characteristic functions as well as domain decomposition and reproduction technique. We start with the simple case of a triangular linear element cut by one interface across which displacement field suffers a jump. The main steps towards the derivation of enrichment functions are as follows: (1) extension of the subfields separated by the interface to the whole element domain and definition of complementary nodal variables; (2) construction of characteristic functions for describing the geometry and physical field; (3) determination of the sets of basic nodal variables; (4) domain decompositions according to Step 3 and then reproduction of the physical field in terms of characteristic functions and nodal variables; and (5) comparison of the piecewise interpolations formulated at Steps 3 and 4 with the standard extended finite element method form, which yields enrichment functions. In this process, the physical meanings of both the basic and complementary nodal variables are clarified, which helps to impose Dirichlet boundary conditions. Enrichment functions for weak discontinuities are constructed from deeper insights into the structure of the functions for strong discontinuities. Relationships between the two classes of functions are naturally established. Improvements upon basic enrichment functions for weak discontinuities are performed so as to achieve satisfactory convergence and accuracy. From numerical viewpoints, a simple and efficient treatment on the issue of blending elements is also proposed with implementation details. For validation purposes, applications of the derived functions to heterogeneous problems with imperfect interfaces are presented. Copyright © 2012 John Wiley & Sons, Ltd.
Alginate grafted with poly(ε‐caprolactone): effect of enzymatic degradation on physicochemical properties
Authors: Benykhlef Samir , Dulong Virginie , Bengharez Zohra , Picton Luc , Guemra Kaddour , Le Cerf Didier
Published: April 2012

The paper discusses the enzymatic behaviour of a series of copolymers composed of alginate grafted with poly(ε‐caprolactone) (PCL) of various lengths and degrees of substitution. The study is focused on viscosity measurements and pyrene probe fluorescence with or without two enzymes: alginate lyase, which breaks the alginate backbone; and esterase, which breaks PCL pendent groups. Alginate lyase is inactive at pH = 3.8 and degrades quickly all copolymers at pH = 6.3. The degradation is not complete and is slowed down by the presence of PCL. Esterase degrades only copolymers with long pendent PCL groups. It has no effect on copolymers when PCL has a length of 530 g mol−1. These systems are good candidates for controlled release of drugs using an enzymatic method. Copyright © 2012 Society of Chemical Industry
Shifting focus from the population to the individual as a way forward in understanding, predicting and managing the complexities of evolution of resistance to pesticides
Authors: Renton Michael
Published: April 2012

The evolution of resistance to pesticides is often conceptualised and modelled at a population level, but population‐based approaches ignore important aspects of variability between individuals within populations that may be essential drivers of resistance. Here it is argued that individual‐based modelling has the potential to generate new insights and perspectives, thus deepening our understanding of the complexities of the evolutionary dynamics of resistance to pesticides. Copyright © 2012 Society of Chemical Industry
Formation Mechanism of LiFePO4 Sticks Grown by a Microwave‐Assisted Liquid‐Phase Process
Authors: Carriazo Daniel , Rossell Marta D. , Zeng Guobo , Bilecka Idalia , Erni Rolf , Niederberger Markus
Published: April 2012

A time‐dependent study on the formation of LiFePO4 with olivine‐type structure is presented. The material is synthesized through a non‐aqueous route in benzyl alcohol assisted by microwave radiation. The LiFePO4 forms with an anisotropic morphology of microscale stick‐like particles. The detailed structure of these particles and their evolution with reaction time is revealed by transmission electron microscopy; a 3D reconstruction of a particle by electron tomography provides insight into the formation mechanism of these sticks. Without applying a thermal post‐annealing treatment or a carbon coating, the electrochemical behavior of the LiFePO4 microsticks is assessed for the preparation of cathodes in lithium‐ion batteries.
Mechanical Behavior of Deformation‐Induced α′‐Martensite and Flow Curve Modeling of a Cast CrMnNi TRIP‐Steel
Authors: Wolf Steffen , Martin Stefan , Krüger Lutz , Martin Ulrich , Lorenz Ulrike
Published: April 2012

For the modeling of the mechanical behavior of a two phase alloy with the rule of mixture (RM), the flow stress of both phases is needed. In order to obtain these information for the α′‐martensite in high alloyed TRIP‐steels, compression tests at cryogenic temperatures were performed to create a fully deformation‐induced martensitic microstructure. This martensitic material condition was subsequently tested under compressive loading at −60, 20, and 100°C and at strain rates of 10−3, 100, and 103 s−1 to determine the mechanical properties. The α′‐martensite possesses high strength and surprisingly good ductility up to 60% of compressive strain. Using the flow stress behavior of the α′‐martensite and that of the stable austenitic steel AISI 316L, the flow stress behavior of the high alloyed CrMnNi TRIP‐steel is modeled successfully using a special RM proposed by Narutani et al.
Simulation of Microsegregation in Multicomponent Alloys During Solidification
Authors: Salvino Ingrid M. , de‐Olivé Ferreira Leonardo , Ferreira Alexandre Furtado
Published: April 2012

A phase‐field model is applied to the simulation of microsegregation and microstructure formation during the solidification of multicomponent alloys. The results of the one‐dimensional numerical simulations show good agreement with those from the Clyne–Kurz equation. Phase‐field simulations of non‐isothermal dendrite growth are examined. Two‐dimensional computation results exhibit different dendrites in multicomponent alloys for different solute concentrations. Changes in carbon concentration appear to affect dendrite morphology. This is due to a larger concentration and a lower equilibrium partition coefficient for carbon. On the other hand, changes in phosphorus concentration affect the dendrites and interface velocity in multicomponent alloys during solidification when phosphorus content is increased from 10−3 mol% P. With additional manganese, the solidification kinetics slow down; dendrite morphology, however, is not affected. The potential of the phase‐field model for applications pertaining to solidification has been demonstrated through the simulations herein.
Physicochemical, morphological, and thermal properties of starches separated from bulbs of four Chinese lily cultivars
Authors: Li Xia , Gao Wenyuan , Jiang Qianqian , Xia Yuzhuo
Published: April 2012

The starches separated from bulbs of four different lily cultivars (Lanzhou, Pinglu, Yixing‐1, and Yixing‐2) were investigated for physicochemical, morphological, crystalline, and thermal properties. AM content of lily bulbs starches from different cultivars ranged from 19.46 to 25.17%. The swelling power of starches ranged between 14.4 and 21.3 g/g, and the solubility ranged from 8.92 and 16.6% at the temperature of 85°C. Four cultivars of lily starches paste had excellent transparency and the transmittance value of Lanzhou lily as high as 54.7%. The transmittance of the gelatinized aqueous starch suspensions, from all lily cultivars, decreased with increase in storage period. The shape of starch granules varied from triangular to cylindrical and XRD of four lily starches all showed B‐type pattern. The transition temperatures and enthalpy of gelatinization (ΔHgel) were determined using DSC. Tp varied from 62.52 to 65.25°C. Pinglu lily starch showed the highest ΔHgel and gelatinization range (Tc–To) index among starches from four different lily cultivars.
Patterns in international bribery: Violations of the foreign corrupt practices act
Authors: Sanyal Rajib
Published: April 2012

An examination of U.S. Department of Justice prosecution of violations of the Foreign Corrupt Practices Act shows that officials in less developed countries are the likely recipients of bribes; that bribery occurs more often in the capital‐intensive industries of energy, construction, telecommunications, and military equipment; that firms more often tend to use intermediaries and agents to consummate illicit transactions rather than directly paying the intended beneficiary; and that the overall motivation for bribing is to secure a particular contract. This article reviews the evolving enforcement of the law and recommends a set of managerial actions to reduce corporate liability and improve governance practices. © 2012 Wiley Periodicals, Inc.
Political patronage and firm performance: Further evidence from Malaysia
Authors: Hassan Taufiq , Kabir Hassan M. , Mohamad Shamsher , Chaw Min Chen
Published: April 2012

This paper investigates the characteristics, performance, and share price reaction of politically connected firms versus a control sample of independent firms in Malaysia. Politically connected firms had higher level of leverage, lower profitability, and lower sales to profitability, and paid lower taxes and lower dividends compared to independent firms. Their share prices increase with the announcement of favorable political events. In terms of performance, the active rent‐seeking activities in return for preferential treatment produce comparable performance to independent firms during an economic upturn. However, their performance deteriorates more than independent firms during an economic downturn. The percentage of ownership of government institutions in politically connected firms is also much lower, and these firms use more Tier 1 auditors than the independent firms. Overall, the findings are consistent with expectations and evidence from similar studies in developed and developing economies. © 2012 Wiley Periodicals, Inc.
Stresses in cohesive‐frictional horizontal layer
Authors: Muravskii G.B.
Published: April 2012

Self‐weight stresses in an isotropic horizontal layer are studied using specific finite elements. In the problem, the material is assumed as non‐linear with the stress‐strain relationship of hyperbolic type and the failure stress determined by Coulomb–Mohr law. The difficulty of the problem consists in the fact that the limit stress depends itself on the unknown stress distribution, so a stress–strain equation cannot be written in an explicit form from the outset. This difficulty is avoided by the method of iteration: a suitable initial stress distribution is supposed and, knowing the material properties, the new stress distribution (appearing as a result of slow gradual weight application) can be found which is taken as the initial for the next iteration, and so on. An importance of the suggested solution consists in the possibility of further study of the layer's dynamic behavior: the found stress distribution allows determining the material properties which should be used in a non‐linear dynamic problem.
Diffraction from a three‐quarter‐plane using an abstract Babinet principle
Authors: Speck F.‐O.
Published: April 2012

The modelling of diffraction of time‐harmonic electromagnetic or acoustic waves from obstacles and screens leads to boundary value problems for the three‐dimensional Helmholtz equation with Dirichlet, Neumann, or other conditions on the boundary. A prominent example is the problem of diffraction from a quarter‐plane in ℝ3, which admits an explicit solution. In this paper the Dirichlet and Neumann problems for the three‐quarter‐plane are solved by an algebraic trick: the matricial coupling of operators associated to “dual” boundary value problems, a kind of abstract Babinet principle.