bluuebunny/crossref_metadata_2025_split huggingface dataset:
The functions and norms that drive university student volunteering
Authors: Francis Julie E. 
Published: December 2009

Abstract

Young adult volunteers are vital to the current and future operations of nonprofit organizations yet many countries report low and declining volunteer participation by this group. Moreover, university students are a particularly under‐utilized and under‐researched segment of potential young adult volunteers. As such, the current study examines the functions and norms that drive university students to volunteer. A survey of 282 students indicates that the Volunteer Functions Inventory (VFI) does not adequately explain the volunteering of today's university students. For instance, t‐tests reveal that the importance of the VFI functions among current students differs significantly to the importance of the functions among the previous generation of students. Also, factor analysis shows that the structure of the VFI model is unstable for the current sample while multiple regression reveals that the VFI explains only 11% of university student volunteering. In contrast, χ2‐tests indicate that volunteering by university students is dependent on the observed volunteering of primary reference group members (i.e., parents, siblings, close friends). The results suggest that nonprofit organizations may need to revise their recruitment strategies for today's university students: rather than appealing to the functional benefits of volunteering, positioning volunteering as the ‘normal’ thing to do may be more successful. Further research is needed to develop a richer understanding of reference group influences on the volunteering behavior of today's young adults.
Copyright © 2009 John Wiley & Sons, Ltd.
Influence of solution properties on the roller electrospinning of poly(vinyl alcohol)
Authors: Cengiz Funda , Dao Tuan Anh , Jirsak Oldrich 
Published: December 2009

AbstractIn recent years, nanofiber production via electrospinning has gained importance because of superior properties of submicron fibers. In this study, the effect of molecular weight, concentration of solution, electric conductivity, surface tension and solution viscosity of the polymer solution on the roller electrospinning of PVA nanofibers was investigated. One nonspinnable and two spinnable polymer species were studied. The effect of polymer concentration and solution viscosity on the electrospinning process throughput, fiber diameters and quality of nanofiber layers was measured. According to the results there is a significant difference in rheological behavior of nonspinnable and spinnable polymer solutions. Electric conductivity and surface tension of the solutions did not influence both throughput and fiber diameter significantly. Whereas molecular weight has an important effect on the spinnability, concentration of the solutions has not. On the contrary, concentration influences the process throughput considerably and properties of nanofibers and nanofiber layers to some extent. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
A prospective investigation of teacher preference and children's perceptions of the student–teacher relationship
Authors: Mercer Sterett H. , DeRosier Melissa E. 
Published: December 2009

AbstractThis study investigated teacher preference, the degree to which a teacher likes a specific student, as a predictor of students' perceptions of teacher preference as well as conflict and support in the student–teacher relationship. Child and teacher reports of teacher preference and child reports of conflict and support were provided in the fall and spring of one academic year. Participants included 1,104 fourth‐grade students in 10 schools. Results indicated that teacher preference predicted change in children's perceived teacher preference. In addition, lower levels of teacher preference directly predicted higher subsequent levels of conflict, but not support. Because teacher preference and children's perceptions of teacher preference were related, lower levels of teacher preference also indirectly predicted higher levels of conflict and lower levels of support. Discussion focuses on the implications of the findings from a dyadic systems conceptualization of student–teacher relationships. © 2009 Wiley Periodicals, Inc.
Study of a lipophilic captopril analogue binding to angiotensin I converting enzyme
Authors: Dalkas Georgios A. , Marchand Damien , Galleyrand Jean‐Claude , Martinez Jean , Spyroulias Georgios A. , Cordopatis Paul , Cavelier Florine 
Published: December 2009

AbstractHuman ACE is a central component of the renin–angiotensin system and a major therapeutic target for cardiovascular diseases. The somatic form of the enzyme (sACE) comprises two homologous metallopeptidase domains (N and C), each bearing a zinc active site with similar but distinct substrate and inhibitor specificities. In this study, we present the biological activity of silacaptopril, a silylated analogue of captopril, and its binding affinity towards ACE. Based on the recently determined crystal structures of both the ACE domains, a series of docking calculations were carried out in order to study the structural characteristics and the binding properties of silacaptopril and its analogues with ACE. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Control of charge separation by electric field manipulation in polymer‐oxide hybrid organic photovoltaic bilayer devices
Authors: White Matthew S. , Olson Dana C. , Kopidakis Nikos , Nardes Alexandre M. , Ginley David S. , Berry Joseph J. 
Published: December 2009

AbstractHybrid polymer/oxide organic photovoltaic (h‐OPV) devices have the potential to replace the organic acceptor component with an inorganic, nano‐structured oxide. This approach leverages the positive attributes of inorganic materials while maintaining the potential processing advantages of organic electronics. By manipulating the carrier concentration of the oxide acceptor layer in bilayer h‐OPV devices, we demonstrate control of the electric field at the planar donor–acceptor interface. The effects of the electric field can be observed in both the JSC and the fill factor of the h‐OPV devices. Furthermore, interfacial layers of TiOx are used on ZnO to prevent recombination of geminate electron–hole pairs. It is shown that interfacial TiOx successfully inhibits recombination only when the electric field is strong enough to sufficiently transfer charges to the ZnO layer. If the interfacial electric field is insufficient, then the TiOx instead serves to enhance recombination at the donor–acceptor interface.
Hydrogen implantation‐induced large area exfoliation in AlN epitaxial layers
Authors: Dadwal U. , Scholz R. , Kumar P. , Kanjilal D. , Christiansen S. , Gösele U. , Singh R. 
Published: December 2009

AbstractHydrogen ion implantation in aluminium nitride (AlN) epitaxial layers grown on 2‐inch c‐plane (0001) sapphire substrates was performed with different fluences in the range of 1 × 1017–2 × 1017/cm2 at various implantation temperatures between liquid nitrogen (LN2) to 300 °C. The post‐implantation thermal annealing behaviour of these samples was studied by using optical microscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM). Our investigations showed that AlN samples that were implanted at LN2 and room temperature (RT) exhibited mostly surface blistering after post‐implantation annealing. On the other hand, the AlN samples that were implanted at 100 and 300 °C showed large area exfoliation of the implanted surface after post‐implantation annealing. The implantation‐induced damage in AlN was analysed by cross‐sectional TEM, which revealed a damage band inside the AlN layer in all the cases that was decorated with hydrogen‐filled nanovoids. These nanovoids showed a greater tendency of agglomerating together to form nanocracks in the as‐implanted state for 100 and 300 °C implanted samples leading eventually to the large area exfoliation after high temperature annealing.
The competition between the intramolecular hydrogen bond and π‐electron delocalization in trifluoroacetylacetone—A theoretical study
Authors: Nowroozi Alireza , Roohi Hossain , Sadeghi Ghoogheri Mohammad Sadegh , Sheibaninia Mohseneh 
Published: December 2009

AbstractConformational study of trifluoroacetylacetone was carried out using the HF, B3LYP, and MP2 methods with the 6‐31G(d, p) and 6‐311++G(d, p) basis sets. All of the results show that the chelated enol structures (E11 and E31) have extra stability with respect to the other forms and one of them (E11) is global minimum. The energy gap between the chelated forms is in the range 0.7–5.9 kJ mol−1. Theoretical calculations show that this compound has an asymmetric double minimum potential energy surface which is in contrast with the electron diffraction result. Moreover, the computational results predict that due to the withdrawing effect of CF3group, hydrogen bond in trifluoroacetylacetone is weaker than the acetylacetone. Because of the more stability of E11, it is expected that the hydrogen bond energy in E11 is greater than the E31, but at all of the computational levels with most extended basis set the converse results were observed. These results clearly show that the hydrogen bond is not a superior parameter in conformational preference and the contribution of resonance is probably greater than the hydrogen bond. Finally, the analysis of this system by quantum theory of atoms in molecules and natural bond orbital methods fairly support the ab initio results. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Theoretical studies on electronic structure and magnetic properties of mixed‐valence uteroferrin active site
Authors: Koizumi Kenichi , Shoji Mitsuo , Yamaguchi Kizashi , Nakamura Haruki , Takano Yu 
Published: December 2009

AbstractThe electronic structure and magnetic interaction of the active site of pig purple acid phosphatase (PAP, uteroferrin) were investigated using pure DFT (UBLYP) and hybrid DFT methods (UB3LYP and UB2LYP). Uteroferrin catalyzes the hydrolysis of a phosphate ester under acidic conditions and contains a binuclear iron center. The mammalian PAPs are expected to be targets for drug design of osteoporosis. Their active sites are typical examples of the Fe(II)‐Fe(III) mixed‐valence system. We studied double exchange interaction of the mixed‐valence system, using the potential energy difference between the Fe(II)‐Fe(III) and the Fe(III)‐Fe(II) states. The pathway of the antiferromagnetic coupling between Fe(III) and Fe(II) were also discussed by using chemical indices, which are evaluated by the occupation numbers of singly occupied natural orbitals. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Computational investigation of wave packet scattering in the complex plane: Numerical analytic continuation techniques
Authors: Rowland Brad A. , Wyatt Robert E. 
Published: December 2009

AbstractIn this study, we utilize Numerical Analytic Continuation (NAC) techniques to compute the complex‐extension of wave packets computed on the real‐axis. Various methods for doing this are reviewed, and the accuracy and stability of one particular method (the Cauchy Method) are examined using a test function. We focus on generating numerically accurate maps of the complex‐extended time‐dependent wave packet for the Gaussian and Eckart barrier scattering problems. We also examine quantum momentum function vector fields and the associated Pólya vector fields for this problem. In a companion study, we present a novel method for solving the complex‐extended Schrödinger equation for points in the complex plane for wave packet scattering from a Gaussian barrier. Several fascinating features of the solution (such as quantized vortices) were presented, but we could only check the veracity of those results on the real‐axis. The method utilized in this study provides an additional check of these results. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Spin‐free quantum electronic structure: Its second quantization and para‐Fermionics
Authors: Klein D. J. 
Published: December 2009

AbstractFirst, the spin‐free formulation of electronic structure is reviewed within the standard first‐quantized framework, with special attention to its manner of correspondence to the standard antisymmetrized space‐spin (ASspin) formulation. Second, within this first‐quantized framework, note is made of some “discrepancies” in the correspondence, for example, regarding mismatches of symmetry‐related degeneracies. Third, a novel second‐quantized spin‐free formulation is introduced to overcome these “discrepancies,” and so achieve a one‐to‐one correspondence between ASspin wave functions and second‐quantized spin‐free wave functions. Yet further, this second‐quantized spin‐free description enables the identification of electrons as “para‐Fermions,” at least in the nonrelativistic limit of spin‐free interactions. From the point of view of elementary particle physics, a rather complete picture of the behavior of para‐Fermions emerges with electrons as a proxy, and so suggests that in fact para‐Fermions would be difficult to distinguish from ordinary Fermions, at least in this nonrelativistic limit or with but few such particles. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Anodic film formation on binary AlMg and AlTi alloys in nitric acid
Authors: Garcia‐Garcia F. J. , Koroleva E. V. , Thompson G. E. , Smith G. C. 
Published: December 2009

AbstractNitric acid is commonly used for surface treatments of aluminium alloys. It is used to clean the surfaces after alkaline etching; it has application in chemical polishing and is also used for electrograining. The majority of these treatments undergo the application of anodic polarisation that results in formation of anodic oxide film. However, little is known about the behaviour of aluminium containing magnesium or titanium in solid solution under such conditions. To reveal the effects of magnesium and titanium alloying additions on anodic film formation in nitric acid, Al‐1800 ppm Mg and Al‐800 ppm Ti alloys were investigated. It was found that porous alumina film developed on the surfaces with reduced efficiency of 40%, due to the reactive nature of nitric acid to alumina. The presence of magnesium and titanium in aluminium had little influence on the efficiency of film growth, as confirmed by the relatively similar thicknesses of oxide formed on binary alloys and aluminium. However, incorporation of magnesium ions into the alumina film led to development of a high‐population density of localised voids near the alloy/film interface. An increased titanium content was found in the film regions close to the alloy/film interface, indicating its oxidation. Copyright © 2009 John Wiley & Sons, Ltd.
Transvaginal cervical length measurement for prediction of preterm birth in women with threatened preterm labor: a meta‐analysis
Authors: Sotiriadis A. , Papatheodorou S. , Kavvadias A. , Makrydimas G. 
Published: December 2009

AbstractObjectivesTo integrate data on the performance of cervical length measurement for the prediction of preterm birth in symptomatic women.MethodsMEDLINE, SCOPUS and manual searches for studies with transvaginal ultrasound measurement of the cervical length in symptomatic women were carried out. Random effects models were used for data integration, and pooled test estimates of sensitivity, specificity, and positive and negative likelihood ratios (LR+ and LR−) were calculated along with their 95% CIs.ResultsTwenty‐eight studies fulfilled the selection criteria. For birth within 1 week from presentation, the pooled sensitivity, specificity, LR+ and LR− of cervical length < 15 mm were 59.9% (95% CI, 52.7–66.8%), 90.5% (95% CI, 89.0–91.9%), 5.71 (95% CI, 3.77–8.65) and 0.51 (95% CI, 0.33–0.80), respectively. The same estimates for studies with presentation at or before 34 + 0 weeks were 71.0% (95% CI, 60.6–79.9%), 89.8% (95% CI, 87.4–91.9%), 5.19 (95% CI, 2.29–11.74) and 0.38 (95% CI, 0.11–1.34), respectively. For prediction of birth before 34 weeks, the pooled sensitivity, specificity, LR+ and LR− of cervical length < 15 mm were 46.2% (95% CI, 34.8–57.8%), 93.7% (95% CI, 90.7–96.0%), 4.31 (95% CI, 2.73–6.82) and 0.63 (95% CI, 0.38–1.04), respectively. There was considerable heterogeneity across studies in most estimates.ConclusionsMeasurement of cervical length in symptomatic women can detect a significant proportion of those who will deliver within 1 week and help to rationalize their management. The considerable heterogeneity across studies may be indicative of methodological flaws, which either were not reported at all or were under‐reported. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Application of a LES technique to characterize the wake deflection of a wind turbine in yaw
Authors: Jiménez Ángel , Crespo Antonio , Migoya Emilio 
Published: December 2009

AbstractWhen a wind turbine works in yaw, the wake intensity and the power production of the turbine become slightly smaller and a deflection of the wake is induced. Therefore, a good understanding of this effect would allow an active control of the yaw angle of upstream turbines to steer the wake away from downstream machines, reducing its effect on them. In wind farms where interaction between turbines is significant, it is of interest to maximize the power output from the wind farm as a whole and to reduce fatigue loads on downstream turbines due to the increase of turbulence intensity in wakes. A large eddy simulation model with particular wind boundary conditions has been used recently to simulate and characterize the turbulence generated by the presence of a wind turbine and its evolution downstream the machine. The simplified turbine is placed within an environment in which relevant flow properties like wind speed profile, turbulence intensity and the anisotropy of turbulence are found to be similar to the ones of the neutral atmosphere. In this work, the model is used to characterize the wake deflection for a range of yaw angles and thrust coefficients of the turbine. The results are compared with experimental data obtained by other authors with a particle image velocimetry technique from wind tunnel experiments. Also, a comparison with simple analytical correlations is carried out. Copyright © 2009 John Wiley & Sons, Ltd.
Gust load reduction concept in wind turbines
Authors: Grzędziński Janusz , Arkadiusz Arkadiusz 
Published: December 2009

AbstractA concept is presented of gust alleviation in wind turbines by using the blade aerodynamic torsional moment as an actuator for forcing the blade to feather in order to reduce aerodynamic loads. The pitching to feather is implemented through a temporary release of the blade‐hub torsional connection after that the blade rotates freely until it reaches the assumed pitch angle. To describe this process, a simple wind turbine model with three elastic blades is formulated and some numerical simulations are performed. The results of the simulations include, among others, the time‐history of the out‐of‐plane blade bending moment in response to the uniform gust, showing that, in this way, it is possible—at least theoretically—to reduce this moment by approximately 2/3 of its peak value. Moreover, the blade pitch angle changes faster than increased by a regular control actuator. Copyright © 2009 John Wiley & Sons, Ltd.
A single dose of vitamin A improves haemoglobin concentration, retinol status and phagocytic function of neutrophils in preschool children
Authors: Jimenez Claudia , Leets Irene , Puche Rafael , Anzola Elsy , Montilla Rosa , Parra Cesar , Aguilera Antonia , García-Casal María N. 
Published: December 2009

Since there is a reported interrelationship between vitamin A and Fe metabolism, and with immunological response, the objective was to evaluate the effect of a single dose of vitamin A administered to preschool children, on Fe and vitamin A nutritional status, anaemia and phagocytic function of neutrophils, 30 d after supplementation. A total of eighty children (sixty-eight supplemented and twelve controls) were supplemented orally with 200 000 IU (60 mg) vitamin A, and evaluated for nutritional, haematological and immunological responses at the beginning of the study and 30 d after supplementation. Parameters studied included Hb, serum ferritin, retinol and Fe concentrations, transferrin saturation, IL-4, interferon-γ and phagocityc capacity of neutrophils using non-fluorescent latex microbeads. After supplementation there was a significant increase in Hb concentration (P = 0·03), mean corpuscular Hb concentration (P = 0·001) and serum retinol (P = 0·0078). Prevalences of anaemia and vitamin A deficiency decreased significantly from 17·6 % to 13·2 % and from 25 % to 13·2 %, respectively. Regarding phagocytic function, there was a significant increase in the number of microbeads engulfed by neutrophils (P < 0·05) and no significant changes in cytokine concentrations at 1 month after treatment. A single dose of 200 000 IU (60 mg) vitamin A administered orally to a group of preschool children with a high prevalence of vitamin A deficiency enhanced serum retinol and Hb concentrations, decreased the prevalence of anaemia and vitamin A deficiency and improved the constitutive phagocytic capacity of neutrophils. Vitamin A supplementation could help to decrease vitamin A deficiency, anaemia prevalence and to improve the innate immunity response in preschool children. The effects were obtained without Fe supplementation.
Placenta: a possible predictor of vitamin A deficiency
Authors: Gomes Mirian Martins , Saunders Claudia , Ramalho Andrea 
Published: December 2009

The objective of the present study is to assess the association between vitamin A deficiency (VAD) evaluated by serum retinol concentration from the mother and umbilical cord and placental concentration of retinol and carotenoids to propose placental values representative of deficiency. Two hundred and sixty-two puerperal women and their newborns were assessed. Concentration of serum and placental retinol and carotenoids was determined by the spectrophotometric method. Receiver operating characteristic (ROC) curve analysis was performed according to two cut-off points (0·70 and 1·05 μmol/l) to represent deficiency in the placental concentration. No difference between averages of placental retinol and carotenoids was observed in the puerperal women regardless of the cut-off point used to define VAD. In relation to the newborns, a decrease (P = 0·012) in placental retinol averages in individuals with VAD was observed when the 1·05 μmol/l cut-off point was adopted. In respect to the placental carotenoid averages, a decrease is observed for both the cut-off points (P = 0·013 and 0·019 for 1·05 and 0·7 μmol/l, respectively). The ROC curve results point to the value of 0·80 μmol/l as representing deficiency with greater values found for sensitivity (66·7 %), specificity (41·7 %) and accuracy (65 %) when the 0·70 μmol/l cut-off point was adopted. The results of the present study show an association between the placental concentration of retinol and carotenoids with clinical VAD, suggesting the need for further studies on more severe cases of deficiency.