bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and exploratory validation of an organizational efficacy scale
Authors: Bohn James G. 
Published: October 2010

AbstractAlthough many instruments have been developed to measure organizational constructs such as citizenship, climate, and organization‐based esteem, to date no scale has been designed specifically to measure efficacy at the organizational level. Tools to measure organizational efficacy in a business context have been recommended for over two decades. This research developed an instrument to assess organizational efficacy, an extension of the theory of self‐efficacy and group‐level efficacy in two studies. The first study included employees of seven organizations to test divergent and convergent validity of the Organizational Efficacy Scale with existing instruments. The second study combined 22 organizations (n = 886) to validate the instrument statistically. The scale demonstrated appropriate levels of convergent and discriminant validity with existing instruments. The final 17 items displayed high reliability and supported a three‐factor solution predicted by efficacy theory around the factors of collaboration, sense of mission, and sense of resilience. Additional psychometric properties for goodness of fit were acceptable.
Differentiation of mesenchymal stem cells in chitosan scaffolds with double micro and macroporosity
Authors: García Cruz Dunia M. , Gomes M. , Reis Rui. L. , Moratal David , Salmerón‐Sánchez Manuel , Gómez Ribelles Jose L. , Mano Joao F. 
Published: October 2010

AbstractBone Marrow mesenchymal stem cells can be induced to differentiate into osteoblasts to regenerate damaged bone tissue using tissue engineering techniques. In this study, we examine the use of chitosan scaffolds with double pore structure prepared by an innovative method that combines freeze gelation (that produces micropores) and particle leaching out technique (that produces interconnected spherical macropores) seeking to enhance the osteogenic differentiation of goat bone marrow stromal cells (GBMSCs). The double pore architecture of the scaffold was characterized by scanning electron microscopy (SEM), microcomputed tomography and confocal laser scanning microscopy. The obtained hierarchical pore structure allowed very efficient seeding of GBMSCs that are able to occupy the whole volume of the scaffold, showing good adhesion and proliferation. GBMSCs were differentiated into osteoblasts as indicated by alkaline phosphatase activity and osteocalcin expression. The results of this study demonstrate that chitosan scaffold may be promising biomaterial for bone regeneration. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
The effect of various denier capillary channel polymer fibers on the alignment of NHDF cells and type I collagen
Authors: Sinclair Kristofer D. , Webb Ken , Brown Philip J. 
Published: October 2010

AbstractIf tissue engineers are to successfully repair and regenerate native tendons and ligaments, it will be essential to implement contact guidance to induce cellular and type I collagen alignment to replicate the native structure. Capillary channel polymer (CC‐P) fibers fabricated by melt‐extrusion have aligned micrometer scale surface channels that may serve the goal of achieving biomimetic, physical templates for ligament growth and regeneration. Previous work characterizing the behavior of normal human dermal fibroblasts (NHDF), on the 19 denier per filament (dpf) CC‐P fibers, demonstrated a need for improved cellular and type I collagen alignment. Therefore, 5 and 9 dpf CC‐P fibers were manufactured to determine whether their channel dimensions would achieve greater alignment. A 29 dpf CC‐P fiber was also examined to determine whether cellular guidance could still be achieved within the larger dimensions of the fiber's channels. The 9 dpf CC‐P fiber appeared to approach the topographical constraints necessary to induce the cellular and type I collagen architecture that most closely mirrored that of native ACL tissue. This work demonstrated that the novel cross‐section of the CC‐P fiber geometry could approach the necessary surface topography to align NHDF cells along the longitudinal axis of each fiber. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Rapid estimation of activation enthalpies for cytochrome‐P450‐mediated hydroxylations
Authors: Mayeno Arthur N. , Robinson Jonathan L. , Reisfeld Brad 
Published: October 2010

AbstractCytochrome P450 (CYP) enzymes play a critical role in detoxication and bioactivation of xenobiotics; thus, the ability to predict the biotransformation rates and regioselectivity of CYP enzymes toward substrates is an important goal in toxicology and pharmacology. Here, we present the use of the semiempirical quantum chemistry method SAM1 to rapidly estimate relative activation enthalpies (ΔH‡) for the hydroxylation of aliphatic carbon centers of various substrates. The ΔH‡ were determined via a reaction path calculation, in the reverse direction (RRP), using the iron‐hydroxo‐porphine intermediate and the substrate radical. The SAM1 ΔH‡ were calculated via unrestricted Hartree‐Fock (UHF) and configuration interaction (CI) formalisms for both the doublet and quartet spin states. The SAM1 RRP ΔH‡, after subtracting a correction factor, were compared with density functional theory (DFT) B3LYP activation energies for two sets of substrates and showed R2 ranging from 0.69 to 0.89, and mean absolute differences ranging from 1.2 ± 1.0 to 1.7 ± 1.5 kcal/mol. SAM1 UHF and CI RRP calculation times were, on average, more than 200 times faster than those for the corresponding forward reaction path DFT calculations. Certain key transition‐state (TS) geometry measurements, such as the forming O···H bond length, showed good correlation with the DFT values. These results suggest that the SAM1 RRP approach can be used to rapidly estimate the DFT activation energy and some key TS geometry measurements and can potentially be applied to estimate substrate hydroxylation rates and regioselectivity by CYP enzymes. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011
Transport properties of graphene nanoribbon‐based molecular devices
Authors: Ding Zongling , Jiang Jun , Xing Huaizhong , Shu Haibo , Dong Ruibin , Chen Xiaoshuang , Lu Wei 
Published: October 2010

AbstractThe electronic and transport properties of an edge‐modified prototype graphene nanoribbon (GNR) slice are investigated using density functional theory and Green's function theory. Two decorating functional group pairs are considered, such as hydrogen‐hydrogen and NH2‐NO2 with NO2 and NH2 serving as a donor and an acceptor, respectively. The molecular junctions consist of carbon‐based GNR slices sandwiched between Au electrodes. Nonlinear I‐V curves and quantum conductance have been found in all the junctions. With increasing the source‐drain bias, the enhancement of conductance is quantized. Several key factors determining the transport properties such as the electron transmission probabilities, the density of states, and the component of Frontier molecular orbitals have been discussed in detail. It has been shown that the transport properties are sensitive to the edge type of carbon atoms. We have also found that the accepter‐donor functional pairs can cause orders of magnitude changes of the conductance in the junctions. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011
Multipole electrostatics in hydration free energy calculations
Authors: Shi Yue , Wu Chuanjie , Ponder Jay W. , Ren Pengyu 
Published: October 2010

AbstractHydration free energy (HFE) is generally used for evaluating molecular solubility, which is an important property for pharmaceutical and chemical engineering processes. Accurately predicting HFE is also recognized as one fundamental capability of molecular mechanics force field. Here, we present a systematic investigation on HFE calculations with AMOEBA polarizable force field at various parameterization and simulation conditions. The HFEs of seven small organic molecules have been obtained alchemically using the Bennett Acceptance Ratio method. We have compared two approaches to derive the atomic multipoles from quantum mechanical calculations: one directly from the new distributed multipole analysis and the other involving fitting to the electrostatic potential around the molecules. Wave functions solved at the MP2 level with four basis sets (6‐311G*, 6‐311++G(2d,2p), cc‐pVTZ, and aug‐cc‐pVTZ) are used to derive the atomic multipoles. HFEs from all four basis sets show a reasonable agreement with experimental data (root mean square error 0.63 kcal/mol for aug‐cc‐pVTZ). We conclude that aug‐cc‐pVTZ gives the best performance when used with AMOEBA, and 6‐311++G(2d,2p) is comparable but more efficient for larger systems. The results suggest that the inclusion of diffuse basis functions is important for capturing intermolecular interactions. The effect of long‐range correction to van der Waals interaction on the hydration free energies is about 0.1 kcal/mol when the cutoff is 12Å, and increases linearly with the number of atoms in the solute/ligand. In addition, we also discussed the results from a hybrid approach that combines polarizable solute with fixed‐charge water in the HFE calculation. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011
Predicting posttraumatic stress symptoms in children following Hurricane Katrina: A prospective analysis of the effect of parental distress and parenting practices
Authors: Kelley Mary Lou , Self‐Brown Shannon , Le Brenda , Bosson Julia Vigna , Hernandez Brittany C. , Gordon Arlene T. 
Published: October 2010

AbstractResearch exhibits a robust relation between child hurricane exposure, parent distress, and child posttraumatic stress disorder (PTSD). This study explored parenting practices that could further explicate this association. Participants were 381 mothers and their children exposed to Hurricane Katrina. It was hypothesized that 3–7 months (T1) and 14–17 months (T2) post‐Katrina: (a) hurricane exposure would predict child PTSD symptoms after controlling for history of violence exposure and (b) hurricane exposure would predict parent distress and negative parenting practices, which, in turn, would predict increased child PTSD symptoms. Hypotheses were partially supported. Hurricane exposure directly predicted child PTSD at T1 and indirectly at T2. Additionally, several significant paths emerged from hurricane exposure to parent distress and parenting practices, which were predictive of child PTSD.
An magnetic resonance imaging T2*‐weighted sequence at short echo time to detect putaminal hypointensity in Parkinsonisms
Authors: Arabia Gennarina , Morelli Maurizio , Paglionico Sandra , Novellino Fabiana , Salsone Maria , Giofrè Laura , Torchia Giusi , Nicoletti Giuseppe , Messina Demetrio , Condino Francesca , Lanza Pierluigi , Gallo Olivier , Quattrone Aldo 
Published: October 2010

AbstractAt 1.5 T, T2*‐weighted gradient echo (GE) sequences are more sensitive in revealing mineral deposition in the basal ganglia than standard T2 weighted sequences. T2*‐weighted GE sequences, however, may detect putaminal hypointensities either in patients affected by parkinsonian syndromes or in healthy subjects. The aim of this study was to identify the magnetic resonance imaging (MRI) T2*‐weighted sequence which more specifically detected putaminal hypointensities differentiating atypical parkinsonian syndromes from Parkinson's disease (PD) and control subjects. In a sample of 38 healthy subjects, we performed three T2*‐weighted GE sequences at increasing time echo (TE; TE = 15 millisecond, TE = 25 millisecond, and echoplanar at TE = 40 millisecond; T2* sequences study). The sequence not showing any putaminal abnormality in the healthy subjects was then used to assess putaminal signal intensity in 189 patients with PD, 20 patients with multiple system atrophy (MSA), 41 patients with progressive supranuclear palsy (PSP), and in 150 age and sex‐matched control subjects. In the T2* sequences study, the T2*‐weighted TE = 15 (T2*/15) did not show any putaminal abnormalities in the healthy subjects. This sequence detected putaminal hypointensities in a significantly higher proportion of patients with MSA (35%, P < 0.05) and PSP (24.4%, P < 0.05) than in patients with PD (5.3%), but in none of the controls. The sensitivity of putaminal hypointensity in T2*/15 sequence was 25.4% for PD, 43.9% for PSP, and 55% for MSA versus controls whereas the specificity was 93.2% for all groups. Despite the suboptimal sensitivity, the high specificity of the T2*/15 sequence performed on routine MRI suggests its usefulness in clinical practice for identifying putaminal hypointensities associated with parkinsonian disorders. © 2010 Movement Disorder Society
A motor cortex excitability and gait analysis on Parkinsonian patients
Authors: Vacherot François , Attarian Shahram , Vaugoyeau Marianne , Azulay Jean‐Philippe 
Published: October 2010

AbstractTranscranial magnetic stimulation (TMS) parameters were recorded in a lower limb muscle and correlated with the gait parameters of 25 patients with Parkinson's disease (PD) with and without dopamine substitution treatment (DST) and 10 control subjects. Single and paired‐pulse TMS were recorded in the tibialis anterior muscle (TA). Gait analysis was performed using a 3D motion analysis system. Parkinsonian patients (PP) did not differ from the control subjects (CS) in terms of relaxed motor threshold, active motor threshold (AMT), cortical silent period (CSP), motor‐evoked potential (MEP) amplitude and area, or paired‐pulse TMS with short interstimulus intervals (ISI). At longer ISIs, paired‐pulse TMS showed that the amplitudes of the conditioned MEPs were lower in untreated PP than in CS. DST partially compensated for this difference. Gait analysis showed that the gait of PP undergoing no treatment was slower and the stride length shorter than normal. Both of these parameters improved under DST, however. Analysis of data obtained on all the subjects combined showed that both of the latter parameters were correlated with the paired‐pulse MEP amplitude and area at longer ISIs. In PP, the cortical areas responsible for the lower limb movements seem to undergo intracortical facilitation (ICF) impairments, whereas the intracortical inhibition process is normal. The ICF level was found to be associated to the stride length and the velocity. The fact that only these two gait parameters were found to be dopa responsive indicates that dopaminergic treatment may improve gait disorders by restoring the ICF. © 2010 Movement Disorder Society
A mixture model of nuchal translucency thickness in screening for chromosomal defects: validation of a single operator dataset
Authors: Gasiorek‐Wiens A. , Kotsis S. , Staboulidou I. , Stumm M. , Wegner R. D. , Soergel P. , Schippert C. , von Kaisenberg C. S. 
Published: October 2010

AbstractObjective(1) To validate the mixture model in a single operator dataset and (2) to compare the detection rates for fetal chromosomal defects obtained from the mixture model with those obtained from either the delta nuchal translucency (NT) or log multiple of the median (MoM) approach.MethodsDatabase query, viable singletons [crown‐rump length (CRL) 45–84 mm corresponding to 11–13+6 weeks], December 1997 to November 2006, examined by Adam Gasiorek‐Wiens, the statistical mixture model was applied.ResultsSeventy‐four of 4171 were lost to follow‐up (1.8%), 4097 singleton pregnancies included trisomy 21 (n = 34, 0.8%), trisomy 18 (n = 20, 0.5%), trisomy 13 (n = 8, 0.2%), Turner syndrome (n = 9, 0.2%) and other chromosomal abnormalities (n = 14, 0.3%). The main findings are that (1) the log‐transformed NT measurements follow a mixture of two Gaussian distributions and (2) the criteria to apply either the delta‐NT or log MoM models are not met. In the normal group, the majority of NT measurements were dependent on the CRL, a small group showed a median independent of the CRL. In the abnormal group it was the opposite. For a 5% false‐positive rate (FPR), the trisomy 21 detection rate was 83%.ConclusionsThe use of the mixture model in a single operator dataset produces results compatible with the original study. The mixture model has thus been validated. Copyright © 2010 John Wiley & Sons, Ltd.
Epidemiologic study of aripiprazole use and the incidence of suicide events
Authors: Ulcickas Yood Marianne , DeLorenze Gerald , Quesenberry Charles P. , Tsai Ai‐Lin , Phillips Syd , Willey Vincent J. , Niemcryk Steve J. , Wells Karen , Skovron Mary Lou , Cziraky Mark J. , Carson William , Oliveria Susan A. 
Published: October 2010

AbstractPurposeBecause second generation antipsychotics (SGA) might affect the risk of suicide, systematic assessment of suicide risk associated with SGA in the postmarketing setting is important and of interest to regulatory authorities. To fulfill a postmarketing request, our objective was to determine suicide event (attempted or completed) incidence in patients with schizophrenia or bipolar disorder, prescribed aripiprazole.MethodsUsing administrative data from three US sources, we assessed study endpoints of suicide attempts and death by suicide in patients aged ≥18 enrolled continuously for ≥3 months in their health plans before receiving their first ever antipsychotic (November 2002–December 2005).ResultsAmong 20 489 antipsychotic users (8985 patient‐years), unadjusted suicide event rates (per 1000 patient‐years) were: 20.69 (aripiprazole); 23.99 (olanzapine); 32.33 (quetiapine); 19.69 (risperidone); 48.52 (ziprasidone). Compared with current users of other SGA combined, aripiprazole users did not have an increased risk of suicide events (crude hazard ratio (HR) = 0.79, 95%CI: 0.48–1.30; adjusted HR = 0.69, 95%CI: 0.42–1.14—(controlling for study site, age, sex, index prescription year, antipsychotic use history, other pharmacotherapy exposure, comorbidity presence, schizophrenia/bipolar disorder, suicide attempts, number inpatient/outpatient encounters).ConclusionsIn this large, multi‐site study, compared with other SGA combined, aripiprazole is not associated with an increased risk of suicide events in an inception cohort of patients with ICD‐9/ICD‐10 codes indicative of schizophrenia or bipolar disorder. Copyright © 2010 John Wiley & Sons, Ltd.
Characterization of copolyesteramides from reactive blending of PET and MXD6 in the molten state
Authors: Samperi Filippo , Montaudo Maurizio S. , Battiato Salvatore , Carbone Domenico , Puglisi Concetto 
Published: October 2010

AbstractPoly(ethylene terephthalate)‐poly(m‐xylylene adipamide) PET‐MXD6 copolymers were prepared by reactive blending of equimolar PET/MXD6 blends at 285 °C for different times in presence of terephthalic acid (1 wt %). First, the partial hydrolysis of PET and MXD6 occurs, yielding oligomers terminated with the reactive aromatic carboxyl groups. These oligomers quickly react with ester and amide inner groups producing a PET‐MXD6 copolymer that may compatibilize the initial biphasic blend. In this homogeneous environment, the aliphatic carboxyl‐terminated MXD6 chains, inactive in the initial biphasic blend, may promote the exchange reactions determining the formation of a random copolymer at longer reaction time (120 min). The progress of exchange reactions, and the microstructure of the formed copolyesteramides, versus the reaction time was followed by 1H and 13C NMR analyses using a CDCl3/TFA‐d/(CF3CO)2O mixture as solvent and applying appropriate mathematical models. Dyads and triads sequences were thoroughly characterized by NMR. Semicrystalline block copolymers were obtained at reaction time lower than 45 min. All PET‐MXD6 copolymers show a single Tg that change as a function of the dyads molar composition in the copolymers. The measured Tg values match with those calculated by a proposed modified Fox equation that take into account the weight fraction of the four dyad components of the PET‐MXD6 copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Poly‐(ε‐caprolactone) (PCL) and poly(hydroxy‐butyrate) (PHB) blends containing seaweed fibers: Morphology and thermal‐mechanical properties
Authors: Barghini Arianna , Ivanova Vassilka I. , Imam Syed H. , Chiellini Emo 
Published: October 2010

AbstractMassive quantities of marine seaweed, Ulva armoricana are washed onto shores of many European countries and accumulates as waste. Attempts were made to utilize this renewable resource in hybrid composites by blending the algal biomass with biodegradable polymers such as poly(hydroxy‐butyrate) and poly‐(ε‐caprolactone). Compression‐molded films were developed and examined for their morphological, thermal and mechanical property. The Ulva fibers were well dispersed throughout the continous matrix exhibiting considerable cohesion with both polymers. Occasionally, regions with exposed fibres or aggregates were visible. About 50% algal content seemed to be an ideal concentration, thereafter, thermal stability was impacted. A progressive decrease in melting heat (ΔHm) was observed with increased algal content as well as a decrease in the crystallinity of the polymer matrix due to the presence of the organic filler. The addition of algal fibres improved the Young modulus of the blends, creating a concomitant loss in percent elongation (El) and ultimate tensile strength. Fiber content above 40% impacted tensile property negatively and composites with over 70% fiber contents composites were too fragile. Data suggest that macro algae are compatible with both polymers and processable as fillers in hybrid blends. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Effects of different composition ratio on the dielectric relaxation and dynamic mechanical properties of poly(ω‐dodecalactam‐co‐ε‐caprolactam‐co‐propylene oxide) copolymers
Authors: Mateva R. , Zhilkova KR. , Zamfirova G. , Díaz‐Calleja R. , Garcia‐Bernabé A. 
Published: October 2010

AbstractThe molecular dynamics of new poly (ω‐dodecalactam‐co‐ε‐caprolactam‐co‐propylene oxide) copolymers (DL/CL/PAC) has been investigated by using dynamic mechanical thermal analysis (DMTA) and dielectric relaxation spectroscopy (DRS) measurements. The copolymers were synthesized via anionic polymerization of relevant lactams activated with carbamoyl derivatives of telechelic hydroxyl terminated polypropylene oxide with isophorone diisocyanate (PAC). The calorimetric, X‐ray diffraction, and DMTA measurements were performed to recognize the influence of the composition ratio and the type of PAC on the physical, thermal, and mechanical properties of the synthesized copolymers. The DRS was used to study the frequency dependence of the dielectric permittivity of some isotherms from −110 to 145 °C. Copolymerization of ε‐caprolactam with about 10 wt % ω‐dodecalactam results in a copolymer that has lower water absorption, a melting point close to that of polyamide 6 and has a high enough degree of crystallinity in respect to high storage modulus. Five dielectric relaxations have been observed in the dielectric spectra, three at lower temperature and two at higher temperature. The copolymers have two glass transition temperatures for polyamide segments and polyether blocks, indicating microphase separation in the copolymers. Other studies directed toward molecular dynamics of polyamide DL/CL/PAC copolymers have not been reported. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010