bluuebunny/crossref_metadata_2025 huggingface dataset:
CEOIdeational Facilitation Leadership and Team Creativity: The Mediating Role of Knowledge Sharing
Authors: Carmeli Abraham , Paulus Paul B.
Published: January 2014

The development of new ventures is often based on collective creative efforts. We conceptualize team creativity as a process of looking for and exploring new solutions and examine whether and howCEOleadership fosters creativity in top management teams (TMT). Data collected from senior executive teams indicate thatCEOideational facilitation leadership is positively related to team knowledge sharing, which in turn results in enhanced team exploratory behaviors. These findings bear important theoretical implications for ways in which leaders can enhance creativity in teams and augment the entrepreneurial direction of executive teams.
NUCB2/nesfatin‐1: A new adipokine expressed in human and murine chondrocytes with pro‐inflammatory properties, an in vitro study
Authors: Scotece Morena , Conde Javier , Abella Vanessa , López Veronica , Lago Francisca , Pino Jesús , Gómez‐Reino Juan J. , Gualillo Oreste
Published: January 2014

Nesfatin‐1 is a recently discovered satiety‐inducing adipokine identified in hypothalamic regions that regulates energy balance. So far, no data exist on NUCB2/nesfatin‐1 localization in human and murine chondrocytes. Here, we therefore investigated NUCB2/nesfatin‐1 gene and protein expression in human and murine chondrocytes and the effect of nesfatin‐1 on pro‐inflammatory cytokines expression. Peptide localization was performed by laser confocal microscopy, NUCB2 mRNA expression was studied by RT‐PCR and protein secretion was measured by XMap technology and Western blot analysis. First, we demonstrated cytoplasmic localization of NUCB2/nesfatin‐1 peptide in both human and murine chondrocytes. We present evidence that both mRNA and protein expression of NUCB2 were increased during the differentiation of ATDC5 murine chondrocyte cell line. Furthermore, we demonstrated that nesfatin‐1 induces IL‐6 and MIP‐1α mRNA expression and protein secretion in ATDC‐5 cells challenged with IL‐1, and also increases COX‐2 mRNA expression in these cells. Finally, nesfatin‐1 provoked a clear induction of pro‐inflammatory agents, such as COX‐2, IL‐8, IL‐6, and MIP‐1α in human primary chondrocytes from OA patients. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:653–660, 2014.
Disruption of the anterior–posterior rotator cuff force balance alters joint function and leads to joint damage in a rat model
Authors: Reuther Katherine E. , Thomas Stephen J. , Tucker Jennica J. , Sarver Joseph J. , Gray Chancellor F. , Rooney Sarah I. , Glaser David L. , Soslowsky Louis J.
Published: January 2014

The rotator cuff assists in shoulder movement and provides dynamic stability to the glenohumeral joint. Specifically, the anterior–posterior (AP) force balance, provided by the subscapularis anteriorly and the infraspinatus and teres minor posteriorly, is critical for joint stability and concentric rotation of the humeral head on the glenoid. However, limited understanding exists of the consequences associated with disruption of the AP force balance (due to tears of both the supraspinatus and infraspinatus tendons) on joint function and joint damage. We investigated the effect of disrupting the APforce balance on joint function and joint damage in an overuse rat model. Twenty‐eight rats underwent 4 weeks of overuse to produce a tendinopathic condition and were then randomized into two surgical groups: Detachment of the supraspinatus only or detachment of the supraspinatus and infraspinatus tendons. Rats were then gradually returned to their overuse protocol. Quantitative ambulatory measures including medial/lateral, propulsion, braking, and vertical forces were significantly different between groups. Additionally, cartilage and adjacent tendon properties were significantly altered. These results identify joint imbalance as a mechanical mechanism for joint damage and demonstrate the importance of preserving rotator cuff balance when treating active cuff tear patients. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:638–644, 2014.
Rapid separation and identification of Strychnos alkaloids metabolites in rats by ultra high performance liquid chromatography with linear ion trap Orbitrap mass spectrometry
Authors: Liu Xiaoyun , Zheng Shuiqing , Jiang Zheng , Liang Chen , Wang Rong , Zhou Zhe , Zhang Yurong , Yu Yunqiu
Published: January 2014

An in vivo study of Strychnos alkaloids metabolites in rats by ultra high performance liquid chromatography with linear ion trap Orbitrap MS is reported for the first time. Two major Strychnos alkaloids compounds including strychnine and brucine were investigated. To obtain optimal extraction efficiency, samples were pretreated by using an SPE plate. The structures of metabolites and their fragment ions were characterized based on the accurate mass and MSn data. Forty‐seven metabolites were identified in rat urine, of which 25 were reported for the first time. Four new metabolism pathways were proposed on the basis of the identified metabolites. This study provides a practical approach for rapidly identifying complicated metabolites, a methodology that could be widely applied not only in forensic and clinically toxicological relevant cases, but also for the structural characterization of metabolites of other compounds.
Psychometric Properties of the Child PTSD Symptom Scale in Latino Children
Authors: Gudiño Omar G. , Rindlaub Laura A.
Published: January 2014

The Child PTSD Symptom Scale (Foa, Johnson, Feeny, & Treadwell, ) is a self‐report measure of posttraumatic stress disorder symptoms (PTSD) in children and adolescents. Despite widespread use of this measure, no study to our knowledge has examined its psychometric properties in Latino children. This study examined the factor structure, internal consistency, and convergent validity of the measure utilizing a sample of 161 Latino students (M = 11.42 years, SD = 0.70) at high risk of exposure to community violence. Confirmatory factor analyses suggested that a 3‐factor model consistent with the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM‐IV‐TR; American Psychiatric Association, ) provided the best fit to the data. Internal consistency of the total scale and subscales was high when completed in English or Spanish. All Child PTSD Symptom Scale scores were positively correlated with violence exposure. As additional evidence of convergent validity, scores evidenced stronger correlations with internalizing symptoms than with externalizing symptoms. Results supported the use of the Child PTSD Symptom Scale as a measure of PTSD severity in Latino children, but additional research is needed to determine appropriate clinical cutoffs for Latino youths exposed to chronic levels of violence. Implications for clinical practice and future research are discussed.
Impact of Combat Deployment on Psychological and Relationship Health: A Longitudinal Study
Authors: Cigrang Jeffrey A. , Wayne Talcott G. , Tatum JoLyn , Baker Monty , Cassidy Daniel , Sonnek Scott , Snyder Douglas K. , Balderrama‐Durbin Christina , Heyman Richard E. , Smith Slep Amy M.
Published: January 2014

Although previous research has indicated an elevated prevalence of posttraumatic stress disorder (PTSD) and other mental health problems among veterans of Operations Iraqi Freedom and Enduring Freedom following deployment, most of this research has been cross‐sectional and has focused on a limited range of military groups and outcome criteria. This investigation was a longitudinal study of U.S. Air Force security forces assigned to a year‐long high‐threat ground mission in Iraq to determine the degree to which airmen's emotional and behavioral health and committed relationships were adversely impacted by an extended deployment to a warzone. Participants were a cohort of 164 security forces airmen tasked to a 365‐day deployment to train Iraqi police. Airmen completed study measures both prior to and 6–9 months following deployment. Rates of deterioration in individual and interpersonal adjustment were both significant and medium to large in magnitude of effect, d = 0.43 to 0.90. Results suggest that the negative effects of deployment are related to levels of traumatic experiences and do not spontaneously remit within the first 6–9 months following return from deployment—particularly among those service members having relatively lower levels of social support.
Poly(ethylene glycol) Hydrogels with Adaptable Mechanical and Degradation Properties for Use in Biomedical Applications
Authors: Parlato Matthew , Reichert Sarah , Barney Neal , Murphy William L.
Published: January 2014

Requirements of hydrogels for drug delivery, wound dressings, and surgical implantation can be extensive, including suitable mechanical properties and tailorable degradation time frames. Herein, an adaptable PEG‐based hydrogel, whose mechanical properties and degradation rate can be systematically adjusted to meet these criteria by altering simple variables such as the PEG molecular weight, is described. The performance of these hydrogels in three physical manipulations (pushing, pulling, and folding), representative of manipulations that they may undergo during typical biomedical use, is also assessed. While not all of these formulations can withstand these manipulations, a subset did, and it is intended to further optimize these formulations for specific clinical applications. Additionally, the outcomes of the physical manipulation tests indicate that simply having a high modulus does not correlate with biomedical applicability.
The Effect of Requests for Positive Evaluations on Customer Satisfaction Ratings
Authors: Jones Michael A. , Taylor Valerie A. , Reynolds Kristy E.
Published: January 2014

In order to focus service employees’ attention on delivering high levels of customer satisfaction, many companies directly reward (or punish) employees who deliver high (low) levels of satisfaction as reported in companies’ formalized satisfaction measurement processes. As a result, many frontline service employees attempt to influence their customers’ satisfaction evaluation by specifically asking them for positive ratings on surveys completed after the service encounter. Using psychological reactance theory, this research considers the impact of requests for positive evaluations on customers’ satisfaction and future intentions. The results indicate that customers who were asked to provide a positive evaluation actually report lower levels of satisfaction compared to customers who were not asked. The results also indicate that the request for positive evaluation has a negative influence on customers’ repurchase intentions and positive word‐of‐mouth intentions, but only for customers who had a more internal locus of control compared to those with a more external locus of control.
Using Polynomial Regression Analysis and Response Surface Methodology to Make a Stronger Case for Value Congruence in Place Marketing
Authors: Zenker Sebastian , Gollan Tobias , Van Quaquebeke Niels
Published: January 2014

Values are an important concept in marketing because they comprise part of peoples’ identity and can thus help marketers separate and target different audiences. Unsurprisingly, places and their marketing initiatives increasingly try to appeal to (potential) residents’ identity by communicating core values. While the notion of value congruence is not novel, most empirical methods in marketing to date only account for the degree rather than the level of congruence. To address this issue, the present article utilizes polynomial regression and response surface methodology (Edwards & Parry, ) in the context of place marketing. Accordingly, the first study shows that the perceived congruence of residents’ own values and the values of stereotypical city inhabitants significantly affect residents’ feelings about their own cities (N = 1257), but with different effects for different values and levels of congruence. This finding holds not only for popular target groups such as the “creative class” but also across all groups. The second study (N = 449) shows that city slogans can effectively communicate specific values and that value congruence leads to a more positive evaluation of the city brand. Finally, the article discusses the benefits of differentiating between levels of congruence both in marketing research in general, and place brand management in particular.
Exploring Attitudes and Affiliation Intentions toward Consumers Who Engage in Socially Shared Superstitious Behaviors: A Study of Students in the East and the West
Authors: Wang Di , Oppewal Harmen , Thomas Dominic
Published: January 2014

Existing literature on superstitious beliefs focuses on consumer purchasing behavior. However, little is known about how superstition‐based consumption behaviors are socially perceived. This paper investigates students’ attitudes toward consumers who engage in socially shared superstitious behaviors. Two studies show that students from Eastern and Western countries have negative attitudes and lower affiliation intentions toward consumers engaging in socially shared superstitious behaviors. As predicted by social judgment theory, this effect is driven by perceived low competence but not by perceived warmth. These negative attitudes and lower affiliation intentions are moderated by the student's superstitiousness. The managerial implications of social perceptions regarding consumer superstitious behavior are discussed.
Effects of Sponsorship Disclosure Timing on the Processing of Sponsored Content: A Study on the Effectiveness of European Disclosure Regulations
Authors: Boerman Sophie C. , van Reijmersdal Eva A. , Neijens Peter C.
Published: January 2014

This study investigates whether the timing of sponsorship disclosure affects viewers’ processing of sponsored content, and whether a disclosure influences the persuasive effect of the sponsored content. A model is proposed in which sponsorship disclosure enhances the recognition of sponsored television content as advertising, which leads to critical processing of the sponsored content. Ultimately, this negatively affects the attitude toward the brand in the sponsored content. This model was supported, but only when the disclosure was displayed prior to or concurrent with the sponsored content. These effects were not found for a sponsorship disclosure shown at the end of the program after the sponsored content. Theoretically, the findings emphasize the importance of disclosure timing. A disclosure displayed prior to or concurrent with the sponsored content, primes the sponsored content and provides sufficient processing time, so viewers recognize the content as advertising and can process it critically. In addition, the findings show that persuasion knowledge and critical processing are important underlying mechanisms for the effect of sponsorship disclosure on brand attitude. Regarding the practical implications for legislators and advertisers, this research demonstrates that sponsorship disclosure can make viewers aware of the sponsored content in television programs. Furthermore, this changes the processing of sponsored content and can also ultimately lead to resistance against persuasion.
How Visual Brand Identity Shapes Consumer Response
Authors: Phillips Barbara J. , McQuarrie Edward F. , Griffin W. Glenn
Published: January 2014

Most brands are represented visually in print advertisements, and these visual representations must consistently identify the brand to the consumers who encounter it. At the same time, some of the particular visual elements used to represent the brand must change over time, because it is not acceptable to run the same ad year after year without refreshing its visual content. To explore these issues, a qualitative exploration was conducted with ad agency art directors and ordinary consumers. The focus was the criteria used by each group to determine when changes in the visual representation of the brand succeed, by staying consistent with the brand's identity, or fail, by violating expectations. Professionals, with their greater aesthetic sensitivity, had a more narrow latitude of acceptance for changes. A follow‐up experiment with consumers showed that aesthetically aware consumers were likewise more sensitive to alterations in visual brand identity than consumers for whom aesthetics were not central. Results are interpreted in terms of assimilation effects and degree of incongruity along with the moderating effect of aesthetic skill.
Preparation of Functional Polyamine Scaffolds via Mitsunobu Post‐Polymerization Modification Reactions
Authors: Kakuchi Ryohei , Theato Patrick
Published: January 2014

A Mitsunobu reaction of trifluoroacetamide (TFA amide) and alcohols is used in a post‐polymerization modification process. The reaction is conducted on polystyrene (PSt) bearing 20 mol% TFA amide groups with 4‐methyl benzyl alcohol in the presence of a N,N,N′,N′‐tetramethylazodicarboxamide and tributylphosphine as mediators. The Mitsunobu reaction on polymer proceeds efficiently, as confirmed by the obvious precipitation generation during the reaction and the conversion of TFA amide moiety reached 88.6% confirmed by 19F NMR measurement, yielding PSt bearing tertiary TFA amide moieties. The obtained polymers featuring tertiary TFA amide moieties are deprotected in the presence of tetrabutylammonium hydroxide as a base to afford corresponding polymers featuring functionalized polyamine scaffolds with 92.5% conversion. In addition, the precise structural assignment is proven by synthesis and analysis of the model monomeric compounds and the respective model polymers.

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A novel mechanism of skin tumor promotion involving interferon‐gamma (IFNγ)/signal transducer and activator of transcription‐1 (Stat1) signaling
Authors: Bozeman Ronald , Abel Erika L. , Macias Everardo , Cheng Tianyi , Beltran Linda , DiGiovanni John
Published: January 2014

The current study was designed to explore the role of signal transducer and activator of transcription 1 (Stat1) during tumor promotion using the mouse skin multistage carcinogenesis model. Topical treatment with both 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) and 3‐methyl‐1,8‐dihydroxy‐9‐anthrone (chrysarobin or CHRY) led to rapid phosphorylation of Stat1 on both tyrosine (Y701) and serine (S727) residues in epidermis. CHRY treatment also led to upregulation of unphosphorylated Stat1 (uStat1) at later time points. CHRY treatment also led to upregulation of interferon regulatory factor 1 (IRF‐1) mRNA and protein, which was dependent on Stat1. Further analyses demonstrated that topical treatment with CHRY but not TPA upregulated interferon‐gamma (IFNγ) mRNA in the epidermis and that the induction of both IRF‐1 and uStat1 was dependent on IFNγ signaling. Stat1 deficient (Stat1−/−) mice were highly resistant to skin tumor promotion by CHRY. In contrast, the tumor response (in terms of both papillomas and squamous cell carcinomas) was similar in Stat1−/− mice and wild‐type littermates with TPA as the promoter. Maximal induction of both cyclooxygenase‐2 and inducible nitric oxide synthase in epidermis following treatment with CHRY was also dependent on the presence of functional Stat1. These studies define a novel mechanism associated with skin tumor promotion by the anthrone class of tumor promoters involving upregulation of IFNγ signaling in the epidermis and downstream signaling through activated (phosphorylated) Stat1, IRF‐1 and uStat1. © 2014 Wiley Periodicals, Inc.
New solvers for higher dimensional poisson equations by reduced B‐splines
Authors: Kuo Hung‐Ju , Lin Wen‐Wei , Wang Chia‐Tin
Published: January 2014

We use higher dimensional B‐splines as basis functions to find the approximations for the Dirichlet problem of the Poisson equation in dimension two and three. We utilize the boundary data to remove unnecessary bases. Our method is applicable to more general linear partial differential equations. We provide new basis functions which do not require as many B‐splines. The number of new bases coincides with that of the necessary knots. The reducing process uses the boundary conditions to redefine a basis without extra artificial assumptions on knots which are outside the domain. Therefore, more accuracy would be expected from our method. The approximation solutions satisfy the Poisson equation at each mesh point and are solved explicitly using tensor product of matrices. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 393–405, 2014
A three‐level linearized finite difference scheme for the camassa–holm equation
Authors: Cao Hai‐Yan , Sun Zhi‐Zhong , Gao Guang‐Hua
Published: January 2014

The Camassa–Holm (CH) system is a strong nonlinear third‐order evolution equation. So far, the numerical methods for solving this problem are only a few. This article deals with the finite difference solution to the CH equation. A three‐level linearized finite difference scheme is derived. The scheme is proved to be conservative, uniquely solvable, and conditionally second‐order convergent in both time and space in the discrete L∞ norm. Several numerical examples are presented to demonstrate the accuracy and efficiency of the proposed method. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 451–471, 2014
A fully adaptive approximation for quenching‐type reaction‐diffusion equations over circular domains
Authors: Beauregard Matthew A. , Sheng Qin
Published: January 2014

This article studies a fully adaptive finite difference method for solving quenching‐type nonlinear reaction‐diffusion equations over circular domains. Although an auxiliary condition at the origin and radial symmetry are imposed, adaptations are accomplished via arc‐length‐based monitoring functions in space and time, respectively. The monotonicity and positivity of the numerical solution are proved following a suitable grid constraint, and the numerical stability is ensured in the von Neumann sense. Theoretical bounds of the critical quenching radius are obtained and then refined through the computation. Computational examples are provided to illustrate the effectiveness and plausibility of the new adaptive computational procedure developed. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 472–489, 2014
A numerical study of electromagnetic waves in periodic waveguides
Authors: Kjellmert Bo
Published: January 2014

Here are considered time‐harmonic electromagnetic waves in a quadratic waveguide consisting of a periodic dielectric core enclosed by conducting walls. The permittivity function may be smooth or have jumps. The electromagnetic field is given by a magnetic vector potential in Lorenz gauge, and defined on a Floquet cell. The Helmholtz operator is approximated by a Chebyshev collocation, Fourier–Galerkin method. Laurent's rule and the inverse rule are employed for the representation of Fourier coefficients of products of functions. The computations yield, for known wavenumbers, values of the first few eigenfrequencies of the field. In general, the dispersion curves exhibit band gaps. Field patterns are identified as transverse electric, TE, transverse magnetic, TM, or hybrid modes. Maxwell's equations are fulfilled. A few trivial solutions appear when the permittivity varies in the guiding direction and across it. The results of the present method are consistent with exact results and with those obtained by a low‐order finite element software. The present method is more efficient than the low‐order finite element method. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 490–513, 2014
Polynomial spectral collocation method for space fractional advection–diffusion equation
Authors: Tian WenYi , Deng Weihua , Wu Yujiang
Published: January 2014

This article discusses the spectral collocation method for numerically solving nonlocal problems: one‐dimensional space fractional advection–diffusion equation; and two‐dimensional linear/nonlinear space fractional advection–diffusion equation. The differentiation matrixes of the left and right Riemann–Liouville and Caputo fractional derivatives are derived for any collocation points within any given bounded interval. Several numerical examples with different boundary conditions are computed to verify the efficiency of the numerical schemes and confirm the exponential convergence; the physical simulations for Lévy–Feller advection–diffusion equation and space fractional Fokker–Planck equation with initial δ‐peak and reflecting boundary conditions are performed; and the eigenvalue distributions of the iterative matrix for a variety of systems are displayed to illustrate the stabilities of the numerical schemes in more general cases. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 514–535, 2014
Numerical inversion of laplace transform via wavelet in partial differential equations
Authors: Hsiao Chun‐Hui
Published: January 2014

This article presents a rational Haar wavelet operational method for solving the inverse Laplace transform problem and improves inherent errors from irrational Haar wavelet. The approach is thus straightforward, rather simple and suitable for computer programming. We define that P is the operational matrix for integration of the orthogonal Haar wavelet. Simultaneously, simplify the formulae of listing table (Chen et al., Journal of The Franklin Institute 303 (1977), 267–284) to a minimum expression and obtain the optimal operation speed. The local property of Haar wavelet is fully applied to shorten the calculation process in the task.

The operational method presented in this article owns the advantages of simpler computation as well as broad application. We still can obtain satisfying solution even under large matrix. Moreover, we do not have numerically unstable problems. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 536–549, 2014
Ependymoblastoma of the brainstem: MRI findings and differential diagnosis
Authors: Nowak Johannes , Seidel Carolin , Pietsch Torsten , Friedrich Carsten , von Hoff Katja , Rutkowski Stefan , Warmuth‐Metz Monika
Published: January 2014

Ependymoblastoma (EBL) is a rare malignant CNS tumor of early childhood, listed as a subgroup of primitive neuroectodermal tumors (PNET) in the 2007 WHO Classification of Tumours of the Central Nervous System. Histologically, EBL can be defined by multilayered, mitotically active “ependymoblastic” rosettes with central lumen as a histological hallmark. The prognosis seems to be far inferior to other embryonal CNS tumors, and known clinical and MRI characteristics of EBL are based on scattered case reports. We present and discuss two uncommon cases of histopathologically confirmed ependymoblastoma that both seem to originate from the brainstem. Pediatr Blood Cancer 2014;61:1132–1134. © 2014 Wiley Periodicals, Inc.
Prognostic factors that increase the risk for reduced white matter volumes and deficits in attention and learning for survivors of childhood cancers
Authors: Reddick Wilburn E. , Taghipour Delaram J. , Glass John O. , Ashford Jason , Xiong Xiaoping , Wu Shengjie , Bonner Melanie , Khan Raja B. , Conklin Heather M.
Published: January 2014

Objective

In children, CNS‐directed cancer therapy is thought to result in decreased cerebral white matter volumes (WMV) and subsequent neurocognitive deficits. This study was designed as a prospective validation of the purported reduction in WMV, associated influential factors, and its relationship to neurocognitive deficits in a very large cohort of both acute lymphoblastic leukemia (ALL) and malignant brain tumors (BT) survivors in comparison to an age similar cohort of healthy sibling controls.

Procedures

The effects of host characteristics and CNS treatment intensity on WMV were investigated in 383 childhood cancer survivors (199 ALL, 184 BT) at least 12 months post‐completion of therapy and 67 healthy siblings that served as a control group. t‐Tests and multiple variable linear models were used to assess cross‐sectional WMV and its relation with neurocognitive function.

Results

BT survivors had lower WMV than ALL survivors, who had less than the control group. Increased CNS treatment intensity, younger age at treatment, and greater time since treatment were significantly associated with lower WMV. Additionally, cancer survivors did not perform as well as the control group on neurocognitive measures of intelligence, attention, and academic achievement. Reduced WMV had a larger impact on estimated IQ among females and children treated at a younger age.

Conclusions

Survivors of childhood cancer that have undergone higher intensity therapy at a younger age have significantly less WMV than their peers and this difference increases with time since therapy. Decreased WMV is associated with significantly lower scores in intelligence, attention, and academic performance in survivors. Pediatr Blood Cancer 2014;61:1074–1079. © 2014 Wiley Periodicals, Inc.
Fabrication of polyimide composite films based on carbon black for high‐temperature resistance
Authors: Kwon Jinuk , Kim Jinyoung , Lee Jeeeun , Han Patrick , Park Dongmyung , Han Haksoo
Published: January 2014

A novel high‐performance material, carbon black (CB) polyimide (PI), was obtained by the chemical synthesis of CB (carbon black N326) with PI. Following its synthesis, several analyses were carried out to investigate the thermal and mechanical properties of the newly synthesized CB‐PI. The thermal decomposition temperature of CB‐PI compared to PI increased by 76°C from 508 to 584°C. The glass transition temperature of CB‐PI as evaluated by differential scanning calorimetry increased by 204°C from 379 to 583°C compared to that of PI. Moreover, the mechanical strength of CB‐PI increased by 16% compared to that of PI. In addition, the analyses confirm that CB and PI in the synthesized CB‐PI were chemically crosslinked, which was shown to be responsible for the superior thermal and mechanical properties of the CB‐PI. POLYM. COMPOS., 35:2214–2220, 2014. © 2014 Society of Plastics Engineers
Investigation of polyethylene/sisal whiskers nanocomposites prepared under different conditions
Authors: Mokhena T.C. , Luyt A.S.
Published: January 2014

In this work, sisal nanowhiskers (SNWs) extracted from sisal fibers were used to reinforce high‐density polyethylene (HDPE) and low‐density polyethylene (LDPE). The nanocomposites were prepared by solution casting from toluene and melt mixing, both followed by melt pressing. In the case of melt mixing, the surfaces of the SNW were also chemically modified with 1 phr of vinyl triethoxy silane to improve their dispersibility and compatibility with the matrices. The SNW had an average length of 197 nm and diameter of 12 nm, and a crystallinity index of 89%. Fourier transform infrared confirmed the surface chemical modification of the SNW. The whiskers were fairly well dispersed in the matrices, regardless of the treatment or preparation method. The presence of whiskers, as well as nanocomposite preparation method, had an observable influence on the storage modulus of LDPE, but very little influence on that of HDPE. There was, however, no significant influence on the degradation behavior of both polymers. The crystallization behavior of the polymers was found to strongly depend on their morphologies. The melting and crystallization behavior of the LDPE nanocomposites were almost unchanged, while an increase in crystallinity was observed for all the HDPE nanocomposites. The tensile properties depended on the type of polymer, the treatment, and the preparation method. Generally there was an improvement in tensile modulus, and a decrease in elongation at break, but the stress at break only improved for the HDPE nanocomposites. POLYM. COMPOS., 35:2221–2233, 2014. © 2014 Society of Plastics Engineers
Preparation and catalytic properties of composites with palladium nanoparticles and poly(methacrylic acid) microspheres
Authors: Bi Shiyin , Li Kun , Chen Xi , Fu Weigui , Chen Li , Sheng Huiying , Yang Qing
Published: January 2014

Palladium (Pd) nanoparticles with different sizes are in situ synthesized by reduction of PdCl2 with NaBH4 as reductant in the presence of poly(methacrylic acid) (PMAA)microspheres. The obtained PMAA/Pd composites are characterized by Fourier transform infrared spectra, X‐ray diffraction, and Transmission electron microscopy. The catalytic activity of the PMAA/Pd composites is investigated using a model reaction, that is, reduction of p‐nitrophenol to p‐aminophenol. The reaction shows first‐order kinetics, and the reaction rate increases with increasing reaction temperature, p‐nitrophenol concentration, and loadings of Pd nanoparticles on PMAA microspheres. The PMAA/Pd composites exhibit good stability, ascribing to the Pd nanoparticles stabilized by PMAA microspheres. POLYM. COMPOS., 35:2251–2260, 2014. © 2014 Society of Plastics Engineers
Impact modification of polypropylene‐based composites using surface‐coated waste rubber crumbs
Authors: Kakroodi Adel Ramezani , Rodrigue Denis
Published: January 2014

Blends of maleated polypropylene (MAPP) with high contents of waste rubber powder, namely ground tire rubber and waste ethylene propylene diene monomer (EPDM) powder, were used as impact modifiers for polypropylene (PP) based composites with different reinforcements (hemp, talc, and milled glass fiber). Adding reinforcements led to increase in modulus (tensile, flexural, and torsion moduli) of PP, while its impact strength decreased noticeably. Impact modification of PP‐based composites was successfully performed via inclusion of MAPP/waste rubber compounds, especially compounds containing waste EPDM powder. Inclusion of such impact modifiers increased impact strength of composites over 80%. The effects of impact modification were more significant for hemp‐ and glass‐filled composites compared to composites containing talc. However, slight decrease in tensile, flexural, and torsion moduli (up to 30%) of the composites was also observed after inclusion of impact modifiers. POLYM. COMPOS., 35:2280–2289, 2014. © 2014 Society of Plastics Engineers
Serum hyperglycosylated human chorionic gonadotrophin at 14–17 weeks of gestation does not predict preeclampsia
Authors: Keikkala Elina , Ranta Jenni K. , Vuorela Piia , Leinonen Reetta , Laivuori Hannele , Väisänen Sari , Marttala Jaana , Romppanen Jarkko , Pulkki Kari , Stenman Ulf‐Håkan , Heinonen Seppo
Published: January 2014

Introduction

Low first‐trimester serum concentrations of hyperglycosylated human chorionic gonadotrophin (hCG‐h) predict later preeclampsia. We studied whether serum hCG‐h at 14–17 weeks of pregnancy also predicts preeclampsia alone or combined with placental growth factor (PlGF) and soluble vascular endothelial growth factor 1 (sVEGFR‐1).

Methods

We conducted a nested case–control study comprising 55 women with subsequent preeclampsia, 21 with gestational hypertension, 30 with a small‐for‐gestational‐age infant, and 83 controls. Serum concentrations of hCG‐h, proportion of hCG‐h to hCG (%hCG‐h), PlGF, and sVEGFR‐1 were converted to multiples of the medians (MoMs) adjusted for gestational age.

Results

Concentrations of hCG‐h or %hCG‐h did not differ between women with subsequent preeclampsia and controls. In women with subsequent preeclampsia, PlGF was lower (0.62 MoM) than in controls (P < 0.001). In receiver‐operating characteristics curve analysis for the prediction of preeclampsia, the area under the curve for hCG‐h or %hCG‐h was not significantly different from 0.5, whereas that for PlGF was 0.746 (95% confidence interval, 0.656–0.836; P < 0.001). Combining hCG‐h or %hCG‐h with PlGF did not improve the prognostic value.

Conclusions

Serum hCG‐h did not improve prediction of preeclampsia in the second trimester. © 2014 John Wiley & Sons, Ltd.
YieldOpt, a model to predict the power output and energy yield for concentrating photovoltaic modules
Authors: Steiner Marc , Siefer Gerald , Hornung Thorsten , Peharz Gerhard , Bett Andreas W.
Published: January 2014

In this work, we discuss three empirical models and introduce one more detailed model named YieldOpt. All models can be used to calculate the power output and energy yield of concentrating photovoltaic (CPV) modules under different ambient conditions. The YieldOpt model combines various modeling approaches: simple model of the atmospheric radiative transfer of sunshine for the spectral irradiance, a finite element method for thermal expansion, ray tracing for the optics, and a SPICE network model for the triple‐junction solar cell. YieldOpt uses a number of constant and variable input parameters, for example, the external quantum efficiency of the cells, the temperature‐dependent spectral optical efficiencies of the optics, the tracking accuracy, the direct normal irradiance, the aerosol optical depth, and the temperature of the lens and the solar cell. To verify the accuracy of the models, the I‐V characteristics of five CPV modules have been measured in a 10‐min interval over a period of 1 year in Freiburg, Germany. Four modules equipped with industrial‐standard lattice‐matched triple‐junction solar cells and one module equipped with metamorphic triple‐junction solar cells are investigated. The higher accuracy of YieldOpt compared with the three empirical models in predicting the power output of all five CPV modules during this period is demonstrated. The energy yield over a period of 1 year was predicted for all five CPV modules with a maximum deviation of 5% by the three empirical models and 3% by YieldOpt. Copyright © 2014 John Wiley & Sons, Ltd.
Luminescent down‐shifting experiment and modelling with multiple photovoltaic technologies
Authors: Alonso‐Álvarez Diego , Ross David , Klampaftis Efthymios , McIntosh Keith R. , Jia Shijun , Storiz Paul , Stolz Theodore , Richards Bryce S.
Published: January 2014

Luminescent down shifting (LDS) is a viable way for improving the short‐wavelength response of many photovoltaic technologies, such as cadmium telluride, copper‐indium‐gallium‐(di)selenide and multi‐crystalline silicon solar cells. In this work, we compare the experimental performance of LDS layers fabricated with six organic dyes—both alone and in mixtures—and two polymers with the theoretical predictions obtained by three different approaches: ray‐tracing simulations and two novel theoretical models. The first model is an analytical description of the LDS process and can reproduce the external quantum efficiency of the solar cell with LDS. The second one is based on a collection of figures of merit that address a desired property of the LDS. The three methods show an excellent agreement with the experimental results in the predicted variation of the short‐circuit current (to within 0.5% in most cases) and help to understand the key factors that influence the performance of LDS, such as the optical coupling, surface roughness and scattering or edge losses. This agreement, regardless of the materials used for LDS and the underlying PV technology, not only supports the validity of the models but also suggests this theoretical formalism as a tool for designing optimised LDS layers in the future. Copyright © 2014 John Wiley & Sons, Ltd.
Synthesis of anionic carbosilane dendrimers via “click chemistry” and their antiviral properties against HIV
Authors: Arnáiz Eduardo , Vacas‐Córdoba Enrique , Galán Marta , Pion Marjorie , Gómez Rafael , Muñoz‐Fernández MA Ángeles , de la Mata F. Javier
Published: January 2014

The synthesis and characterization of four families of anionic carbosilane dendrimers bearing carboxylate, phosphonate, naphthylsulfonate, and sulfate terminal groups prepared by cycloaddition of azide–alkyne catalyzed by copper (CuAAC) are presented here. For the preparation of these anionic carbosilane dendrimers, two strategies starting from azide‐terminated carbosilane dendrimers were followed: (i) click coupling of neutral alkynes followed by derivatization into anionic moieties or (ii) click coupling of anionic alkynes. Both strategies require different reaction conditions in order to accommodate the different substrate polarities. These anionic dendrimers, in general, do not present cell toxicity in vitro until concentration up to 20 µM. Therefore, they can be used in inhibition experiments in concentrations below this limit. We have observed that dendrimers bearing phosphonate groups possess poor anti‐HIV capabilities in vitro in PBMCs, while carboxylate dendrimers can reduce HIV infection levels moderately. On the other hand, sulfate and naphthylsulfonate dendrimers are powerful anti‐HIV agents and their antiviral activity is generation and concentration dependent. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1099–1112
Synthesis and properties of polyhydroxyurethane bearing silicone backbone
Authors: Ochiai Bungo , Kojima Haruka , Endo Takeshi
Published: January 2014

Polyhydroxyurethane bearing silicone backbone was prepared by polyaddition of silicone diamines with a bifunctional five‐membered cyclic carbonate prepared from the corresponding diepoxide and CO2. Polymerization in propylene glycol methyl ether acetate proceeded smoothly, and polymers could be obtained in high yields under appropriate conditions. The introduced silicone moieties improved the hydrophobicity and lowered the glass transition temperature keeping thermal stability. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1113–1118
Bioefficacy of the triterpenoid friedelin againstHelicoverpa armigera(Hub.) andSpodoptera litura(Fab.) (Lepidoptera: Noctuidae)
Authors: Baskar Kathirvelu , Duraipandiyan Veeramuthu , Ignacimuthu Savarimuthu
Published: January 2014

BACKGROUND

The triterpenoid friedelin isolated from hexane extract ofAzima tetracanthaleaves was evaluated for its antifeedant, larvicidal and pupicidal activities againstHelicoverpa armigeraandSpodoptera lituraat 125, 250, 500 and 1000 ppm concentration.

RESULTS

Friedelin exhibited antifeedant (84.57 and 75.28%), larvicidal (72.88 and 66%) and pupicidal (76.18 and 66.66%) activities againstH. armigeraandS. liturarespectively. The homogeneity of variances (Levene statistic) showed significant deviation for the antifeedant, larvicidal and pupicidal activities of friedelin againstH. armigeraandS. litura. It exhibitedLC50values of 130.47 and 226.41 ppm for antifeedant and 509.56 and 607.99 ppm for larvicidal activities againstH. armigeraandS. liturarespectively. In linear regression analysis, significant and high correlation was noted between concentration and antifeedant activity withR2= 0.84 and 0.79 and between concentration and larvicidal activity withR2= 0.81 and 0.76 againstH. armigeraandS. liturarespectively.

CONCLUSION

Regression between antifeedant and larvicidal activities also showed significant activity (P= 0.00) withR2= 0.79 forH. armigeraandR2= 0.70 forS. litura. Friedelin showed good activity against both the pests. Friedelin did not show any toxicity against freshwater fishCyprinus carpioat 100 mg L−1. Friedelin could be used to prepare a botanical formulation to control the agricultural pests. © 2014 Society of Chemical Industry
Domain glass
Authors: Salje E. K. H. , Ding X. , Aktas O.
Published: January 2014

Microstructural patterns of twin boundaries and tweed in ferroelastic materials display typical aspects of glasses. The patterns are complex, their dynamics follows Vogel–Fulcher statistics and their field cooling–non‐field cooling hysteresis is similar to those described in this issue as ‘strain glasses’. The difference is that domain glasses do not need extrinsic defects to form. In the paraelastic phase, an intrinsic tweed pattern dominates the high temperature precursor regime. Experimentally, massive elastic precursor softening is related to polar standing waves, which are attributed to the glassy relaxation of the tweed pattern. In the ferroelastic phase we find a complex twin pattern when the sample is strained with a constant strain rate. The dynamics of the pattern formation is a‐thermal at low temperatures and follows Vogel–Fulcher statistics at moderately high temperatures. It is argued that domain boundary patterns can hence evolve glass‐like states while the underlying matrix remains fully crystalline without any defect induced disorder.
Proposal of an empirical velocity spectrum formula in low‐wind speed conditions
Authors: Mortarini L. , Anfossi D.
Published: January 2014

Low‐wind spectra are investigated through the analysis of sonic anemometer observations gathered in three experimental campaigns: the Urban Turbulence Project, the NOrthern hemisphere climate Processed land‐surface EXperiment and the Graz experiment. From the comparison of the horizontal Eulerian experimental spectra computed in this work with those available in the literature it is shown that in low‐wind conditions the spectra present an evident peak in the lower frequency range, that it is not accounted for in the classical formulations. This is a consequence of the oscillatory behaviour of the horizontal wind, and the peak frequency depends on the meandering time‐scale of the horizontal wind components. In contrast with previous studies the meandering behaviour is observed in both stable and unstable conditions. A new formula for the low‐wind velocity spectrum is proposed and evaluated.
“What Motivates Her”: Motivations for Considering Labial Reduction Surgery as Recounted on Women's Online Communities and Surgeons' Websites
Authors: Zwier Sandra
Published: January 2014

Introduction

Increasing numbers of women are seeking labial reduction surgery. We studied the motivations for considering labial reduction surgery as recounted on women's online communities and surgery provider's websites.

Aims

The study analyzed motivations for considering labial reduction surgery expressed by women on online communities, looked at the role of the women's age and nationality, compared findings with motivations indicated on the websites of an international sample of surgery providers, and identified similarities to and differences from what is known from extant studies.

Methods

Quantitative content analysis of the posts of 78 American, British, and Dutch women on online communities, and 40 international surgery providers' websites about labial reduction surgery was conducted.

Main Outcome Measures

Main outcome measures concerned the incidence and prominence of different motivational categories (functional/emotional and discomfort/enhancement related). Differences in motivations as a function of age, national background, and women's vs. surgeons' stated motivations were tested.

Results

Emotional discomfort regarding self-appearance and social and sexual relationships was found to be the most frequent and most prominent motivation for considering labial reduction surgery on women's online communities, regardless of age and national background. Functional discomfort and desired emotional enhancement ranked second. Very few age or national differences were found. The surgeons' websites recognized functional discomfort more and elaborated upon emotional issues in sexual relationships less than members of the online communities.

Conclusions

Feelings of emotional and psychosexual distress in addition to functional distress are a highly prevalent motivation among women considering labial reduction surgery. Emotional distress appears to be greater and more freely emphasized when women communicate on online communities, while functional issues appear to receive greater notice on surgery provider's websites.