bluuebunny/crossref_metadata_2025 huggingface dataset:
Osmogen‐Mediated One‐Step Technique of Fabricating Hollow Microparticles for Encapsulation and Delivery of Bioactive Molecules
Authors: Kharel Sharad , Lee Wei Li , Lee Xuan Yi , Loo Say Chye Joachim
Published: November 2016

Microparticulate systems composed of biodegradable polymers, such as poly(d,l‐lactic‐co‐glycolic acid) (PLGA), are widely used for controlled release of bioactive molecules. However, the acidic microenvironment within these microparticles, as they degrade, has been reported to perturb the configuration of most encapsulated proteins. In addition, these polymer particles are also reported to suffer from unrealistically slow and incomplete release of proteins. To address these drawbacks, hollow PLGA microparticles are fabricated through a novel one‐step oil‐in‐water emulsion solvent evaporation technique, by capitalizing on the osmotic property of an osmogen. The effects of fabrication para­meters on particle size and morphology, i.e., volume space of hollow cavity and shell thickness, are also studied. These hollow microparticles are subsequently loaded with bovine insulin microcrystals. It is shown that insulin release profiles can be tuned by simply changing the amount of osmogen in the formulation. At the same time, these hollow microparticles are shown to be effective in maintaining the bioactivity of the encapsulated protein.

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Enhanced Sealing by Hydrophobic Modification of Alaska Pollock‐Derived Gelatin‐Based Surgical Sealants for the Treatment of Pulmonary Air Leaks
Authors: Mizuta Ryo , Taguchi Tetsushi
Published: November 2016

Pulmonary air leaks are medical complications of thoracic surgery for which fibrin sealant is the main treatment. In this study, innovative sealants based on hydrophobically modified Alaska pollock‐derived gelatin (hm‐ApGltn) and a poly(ethylene)glycol‐based 4‐armed cross‐linker (4S‐PEG) have been developed and their burst strengths have been evaluated using fresh rat lung. The developed sealants show higher lung burst strength compared with the nonmodified original ApGltn (Org‐ApGltn)‐based sealant and a commercial fibrin sealant. The maximum burst strength of the hm‐ApGltn‐based sealant is 1.6‐fold higher than the Org‐ApGltn‐based sealant (n = 5, p < 0.05), and 2.1‐fold higher than the commercial fibrin sealant (n = 5, p < 0.05). Cell culture experiments show that modification of ApGltn with cholesteryl or stearoyl groups effectively enhances anchoring to the cell surface. In addition, binding constants between hm‐ApGltn and extracellular matrix proteins such as fibronectin and fibrillin are increased. Therefore, the new hm‐ApGltn/4S‐PEG‐based sealant has the potential for applications in thoracic surgery.

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Social Networks on Cashback Websites
Authors: Ballestar María Teresa , Sainz Jorge , Torrent‐Sellens Joan
Published: November 2016

The relevance of Cashback sites as a profitable business model has grown considerably over the last decade, where customer's social networks have been one of the most important keys of success. Hence, the success of cashback websites business model not only lays on strategies such as offering a wide portfolio of affiliate merchants and competitive cashbacks per transaction to attract new customers, but also on their ability of engaging them and enrolling new target customers through recommendation in a word‐of‐mouth marketing strategy. By a applying this kind of strategies, both the recommender and the referee benefit from referee's transactions in the network, meaning that benefits for customers and companies grow at the same time that the customer's social network grows and become more active. Consequently, this research focuses on the analysis of the impact of customer's social network on cashback websites from two different perspectives. From the customer's perspective, determining the impact of the social network composition and their activity in customer's benefits of cashback. Second, the research focuses on the ecommerce's perspective, testing which kind of customers, characterized by whether they have social network or not, are more profitable to the brand in terms of purchase behavior and loyalty. The findings are a step forward to understand customer behaviour and the relevance of social networks on cashback websites business model and help the companies to establish the basis to develop new digital marketing strategies less concentrated in media advertisements and oriented to increase customer acquisition, retention, and profitability.
eWOM on Travel Agency Selection: Specialized versus Private Label
Authors: Bigné Enrique , Caplliure Eva‐María , Miquel María‐José
Published: November 2016

In the travel industry, electronic word of mouth (eWOM) elicits a major influence on consumers’ decision making. Travel retailers are facing the new challenges derived from the different nature of their competitors—big hypermarkets, for instance, are extending their brands to travel services—and the challenges derived from online comments that consumers have access to. With a sample of 263 tourists, and using a fuzzy‐set qualitative comparative analysis data analysis, this paper shows how the selection between a specialized travel agency and a private label (PL) agency is influenced by five factors: the usefulness attached to online reviews by users and the valence of those online reviews, attitude and experience with PL, and the individual's value consciousness. The contribution of this paper not only comes from the novelty of considering PL in the context of travel agencies, but also from using a relatively novel data analysis approach useful for analyzing management issues.
Cross‐cultural Perceptions of Onshore Guided Tours: A Qualitative Approach Based on eWOM
Authors: Buzova Daniela , Sanz‐Blas Silvia , Cervera‐Taulet Amparo
Published: November 2016

Recognizing the importance of the study of guided tour experiences and being aware of the cross‐cultural variations of services’ perceptions, the purpose of this article is to examine if cruise tourists from the two main generating markets (Europe and North America) perceive differently a port of call guided tour based on the content of the eWOM generated. The data set was comprised of 334 reviews on guided tours undertaken in Spanish ports of call and published during the period 2009–2015 on the major travel Web site Tripadvisor. The thematic content analysis of the data was performed using the text mining software Leximancer. The results yielded different pictures for the experiences described by both cultures, with Europeans valuing the tour in terms of efficiency and North Americans praising guide's performance and tailor‐made tour services. Based on these findings, practical implications are discussed.
Motivation Recipes for Brand‐Related Social Media Use: A Boolean—fsQCA Approach
Authors: Saridakis Charalampos , Baltas George , Oghazi Pejvak , Hultman Magnus
Published: November 2016

Social media Web sites such as Facebook, Twitter, and Instagram provide various means for users to interact with others, by creating, sharing, and commenting on content about anything, including brands and products. Such online brand‐related activities may significantly influence a firm's operations. To effectively manage these influences, marketers should understand consumer's motivations to engage in brand‐related social media use. This paper is one of the very few efforts to come to such an understanding. In this direction, a set‐theoretic comparative approach is implemented—namely, fuzzy set qualitative comparative analysis—as a means to capitalize on the merits of both qualitative and quantitative techniques, and provide a more nuanced coverage of how motives and their combinations affect social media use. The results of the proposed approach are compared with the results derived from the implementation of a mainstream quantitative analytical technique (i.e., multiple regression analysis), as well as the results of the qualitative study of Muntinga, Moorman, and Smit ()—the only study so far examining different types of brand‐related social media use and their motivations. By examining motivations for the full spectrum of social media use types (i.e., consuming, contributing and creating), the paper provides marketers and brand managers with valuable insights into online consumer behavior in a social media dominated era.
Consumer Trust in User‐Generated Brand Recommendations on Facebook
Authors: Chari Simos , Christodoulides George , Presi Caterina , Wenhold Jil , Casaletto John P.
Published: November 2016

The transparency of social Web paves the way for user‐generated content (UGC) to become a trusted form of brand communication. Research offers little guidance on UGC and trust development in social networking sites (SNS) and has yet to debate the effects of ad‐skepticism in the context of UGC and SNS. This study builds on theory to develop a conceptual framework that yields insights into the development of consumer trust toward user‐generated brand recommendations (UGBR). A set‐theoretic approach using fuzzy set qualitative comparative analysis is applied to data derived from 303 consumers. The study findings suggest that high levels of trust in UGBR are associated with high levels of trust toward Facebook friends and provide support for the moderating role of ad‐skepticism. Benevolence and integrity are found to be necessary/core conditions for the development of trust toward Facebook friends. Ability and disposition to trust are of peripheral importance. The significance of the findings and their implications are discussed.
Standardization, Adaptation, and Personalization of International Corporate Social Media Communications
Authors: Hatzithomas Leonidas , Fotiadis Thomas A. , Coudounaris Dafnis N.
Published: November 2016

This research examines both the standardization versus adaptation of Vodafone's international corporate social media communications strategy in Study 1 and consumers’ attitudes toward this strategy in Study 2. Study 1 investigates Vodafone's strategy in Facebook through a content analysis and Study 2 focuses on consumers’ attitudes through a qualitative approach of 12 Facebook fans: 6 in the UK and 6 in Greece. The findings reveal that Vodafone implements a local strategy in corporate Facebook campaigns, taking into account the cultural differences between these countries. The results also indicate that the debate on the international corporate Facebook communications strategy should extend beyond the standardization/adaptation dichotomy, pointing out the pivotal role of personalization.
Strategizing for Financial Technology Platforms: Findings from Four Russian Case Studies
Authors: Kabakova Oksana , Plaksenkov Evgeny , Korovkin Vladimir
Published: November 2016

This article studies the business strategy of digital financial platforms and creation of ecosystems. The authors assume the general methodological approach of grounded theory to study four cases of financial technology platforms from Russia; the sample represents companies focusing both on solutions for the front end (consumers) and back end (middle of the value chain). The research finds that the top executives of the companies, which create and operate the digital platforms, have an approach to business strategy that is significantly different from that of the traditional business. They defy the pragmatism of predicting the market development and planning the company's actions in accordance with such predictions. Strategic paradigm of these companies is based on the notions of inclusivity, dynamism, and reliance on independent participants of a business ecosystem. Though a radical departure from the traditional business strategy, such an approach has brought demonstrable business success across the time span of a decade. The idea of “platform–ecosystem” can also be fruitful as a tool of solving important socioeconomic issues such as financial inclusion in the emerging markets.
Development of carbon fibre‐reinforced plastic (CFRP) crash absorbers with stable crushing behaviour considering the connection to the bumper system
Authors: Szlosarek R. , Bombis F. , Mühler M. , Kröger M. , Karall T.
Published: November 2016

Crash absorbers made of fibre‐reinforced plastics becoming more and more popular to reduce the mass in the front section of cars. Various research projects analysed the high specific energy absorption and the stable crushing behaviour of this material, however without examining the connection to other car body components. This paper focuses on the connection of the crash absorbers to the bumper system, particularly regarding to the crushing behaviour. An initial step focused on the development of a crash absorber made of carbon‐fibre‐reinforced plastic, which shows similar energy absorption compared to absorbers made of aluminium. A following step investigated various connection concepts using a drop tower. These first connection concepts resulted in unstable crushing behaviour. The finite element simulation of the tests delivered additional information about the reasons for the insufficient crushing behaviour. Subsequently, a simulation of various connection concepts turned out suitable connection concepts. A final drop tower test investigated the best connection concept. The developed connection system shows similar to the unmodified crash absorber stable crushing behaviour.
Innovative hybrid laminates of aluminium alloy foils and fibre‐reinforced thermoplastic layers
Authors: Nestler D. , Trautmann M. , Nendel S. , Wagner G. , Kroll L.
Published: November 2016

The article is about the consolidation of semi‐finished products from fibre‐reinforced polyamide layers and aluminium alloy foils to produce hybrid laminates. In addition it also focuses on the suitable interface engineering between fibre‐reinforced plastics and metal foils, as well as the resulting mechanical properties. The mechanical, chemical and physical surface treatment methods, as well as the adhesive layers for the material combination of carbon fibre‐reinforced polyamide 6 and the aluminium alloy EN AW‐6082 T4 are examined at the thermally bonded overlapping joints and subsequently evaluated regarding the possible in‐line integration in a large‐scale production. The mechanical properties of various hybrid laminates with a varied fibre‐reinforced structure are compared to each other. The mechanical properties of the hybrid material system can be improved by the addition of extra layers of polyamide 6 and glass fibre‐reinforced polyamide 6, which in turn also add a gradient of the material to the boundary surface between the aluminium and the carbon fibre‐reinforced plastic.
Susceptibility loci of CNOT6 in the general mRNA degradation pathway and lung cancer risk—A re‐analysis of eight GWASs
Authors: Zhou Fei , Wang Yanru , Liu Hongliang , Ready Neal , Han Younghun , Hung Rayjean J. , Brhane Yonathan , McLaughlin John , Brennan Paul , Bickeböller Heike , Rosenberger Albert , Houlston Richard S. , Caporaso Neil , Landi Maria Teresa , Brüske Irene , Risch Angela , Ye Yuanqing , Wu Xifeng , Christiani David C. , Goodman Gary , Chen Chu ,   Transdisciplinary Research in Cancer of the Lung (TRICL) Research Team, Amos Christopher I. , Wei Qingyi
Published: November 2016

Purpose: mRNA degradation is an important regulatory step for controlling gene expression and cell functions. Genetic abnormalities involved in mRNA degradation genes were found to be associated with cancer risks. Therefore, we systematically investigated the roles of genetic variants in the general mRNA degradation pathway in lung cancer risk. Experimental design: Meta‐analyses were conducted using summary data from six lung cancer genome‐wide association studies (GWASs) from the Transdisciplinary Research in Cancer of the Lung and additional two GWASs from Harvard University and deCODE in the International Lung Cancer Consortium. Expression quantitative trait loci analysis (eQTL) was used for in silico functional validation of the identified significant susceptibility loci. Results: This pathway‐based analysis included 6816 single nucleotide polymorphisms (SNP) in 68 genes in 14 463 lung cancer cases and 44 188 controls. In the single‐locus analysis, we found that 20 SNPs were associated with lung cancer risk with a false discovery rate threshold of <0.05. Among the 11 newly identified SNPs in CNOT6, which were in high linkage disequilibrium, the rs2453176 with a RegulomDB score “1f” was chosen as the tagSNP for further analysis. We found that the rs2453176 T allele was significantly associated with lung cancer risk (odds ratio = 1.11, 95% confidence interval = 1.04–1.18) in the eight GWASs. In the eQTL analysis, we found that levels of CNOT6 mRNA expression were significantly correlated with the rs2453176 T allele, which provided additional biological basis for the observed positive association. Conclusion: The CNOT6 rs2453176 SNP may be a new functional susceptible locus for lung cancer risk. © 2016 Wiley Periodicals, Inc.
Genome‐wide DNA methylation analysis identifies MEGF10 as a novel epigenetically repressed candidate tumor suppressor gene in neuroblastoma
Authors: Charlet Jessica , Tomari Ayumi , Dallosso Anthony R. , Szemes Marianna , Kaselova Martina , Curry Thomas J. , Almutairi Bader , Etchevers Heather C. , McConville Carmel , Malik Karim T. A. , Brown Keith W.
Published: November 2016

Neuroblastoma is a childhood cancer in which many children still have poor outcomes, emphasising the need to better understand its pathogenesis. Despite recent genome‐wide mutation analyses, many primary neuroblastomas do not contain recognizable driver mutations, implicating alternate molecular pathologies such as epigenetic alterations. To discover genes that become epigenetically deregulated during neuroblastoma tumorigenesis, we took the novel approach of comparing neuroblastomas to neural crest precursor cells, using genome‐wide DNA methylation analysis. We identified 93 genes that were significantly differentially methylated of which 26 (28%) were hypermethylated and 67 (72%) were hypomethylated. Concentrating on hypermethylated genes to identify candidate tumor suppressor loci, we found the cell engulfment and adhesion factor gene MEGF10 to be epigenetically repressed by DNA hypermethylation or by H3K27/K9 methylation in neuroblastoma cell lines. MEGF10 showed significantly down‐regulated expression in neuroblastoma tumor samples; furthermore patients with the lowest‐expressing tumors had reduced relapse‐free survival. Our functional studies showed that knock‐down of MEGF10 expression in neuroblastoma cell lines promoted cell growth, consistent with MEGF10 acting as a clinically relevant, epigenetically deregulated neuroblastoma tumor suppressor gene. © 2016 The Authors. Molecular Carcinogenesis Published by Wiley Periodicals, Inc.
PTENp1, a natural sponge of miR‐21, mediates PTEN expression to inhibit the proliferation of oral squamous cell carcinoma
Authors: Gao Ling , Ren Wenhao , Zhang Linmei , Li Shaoming , Kong Xinjuan , Zhang Hao , Dong Jianwei , Cai Guangfeng , Jin Changxiong , Zheng Danqing , Zhi Keqian
Published: November 2016

PTENp1, non‐coding RNA (ncRNA) pseudogene, is involved in oral squamous cell carcinoma (OSCC). The precise effects mediated by PTENp1 transcripts within intricate regulatory networks involving molecular interactions with ancestral gene PTEN and tumorigenicity in OSCC remain unclear. Here, we found that PTENp1 was aberrantly expressed in OSCC. There was a positive correlation between the expression levels of PTENp1 and PTEN. Further, we showed that PTENp1 acted as a competing endogenous RNA that protects PTEN transcripts from being inhibited by miR‐21, and consequently inhibited proliferation and colony formation and triggered S‐G2/M cell cycle arrest through the AKT pathway. Also, the homogeneous relationship between expression of PTENp1 and PTEN was confirmed in OSCC tumor xenografts. Finally, low expression of PTENp1 and PTEN was negatively associated with histological differentiation and OSCC prognosis. The present work provided the first evidence for the extraordinary crosstalk among PTENp1, PTEN, and miR‐21, and rendered a new light on the treatment of OSCC. © 2016 Wiley Periodicals, Inc.
Fatigue, Sleep Disturbances, and Their Influence on Quality of Life in Cervical Dystonia Patients
Authors: Smit Marenka , Kamphuis Arwen S. J. , Bartels Anna L. , Han Vladimir , Stewart Roy E. , Zijdewind Inge , Tijssen Marina A.
Published: November 2016

Background

Nonmotor symptoms (NMS) are highly prevalent in cervical dystonia (CD). In general, fatigue and sleep are important NMS that determine a decreased health‐related quality of life (HR‐QoL), but their influence in CD is unknown. The authors systematically investigated fatigue, excessive daytime sleepiness (EDS), and sleep quality in patients with CD and controls and assessed the influence of psychiatric comorbidity, pain, and dystonia motor severity. They also examined the predictors of HR‐QoL.

Methods

The study included 44 patients with CD and 43 matched controls. Fatigue, EDS, and sleep quality were assessed with quantitative questionnaires and corrected for depression and anxiety using analysis of covariance. The Toronto Western Spasmodic Torticollis Rating Scale and the Clinical Global Impression Scale‐jerks/tremor subscale were used to score motor severity and to assess whether motor characteristics could explain an additional part of the variation in fatigue and sleep‐related measures. HR‐QoL was determined with the RAND‐36 item Health Survey, and predictors of HR‐QoL were assessed using multiple regression.

Results

Fatigue scores were increased independently from psychiatric comorbidity (4.0 vs. 2.7; P < 0.01), whereas EDS (7.3 vs. 7.4; P = 0.95) and sleep quality (6.5 vs. 6.1; P = 0.73) were highly associated with depression and anxiety. In patients with CD, motor severity did not explain the variations in fatigue (change in the correlation coefficient [ΔR2] = 0.06; P = 0.15), EDS (ΔR2 = 0.00; P = 0.96), or sleep quality (ΔR2 = 0.04; P = 0.38) scores. Fatigue, EDS, psychiatric comorbidity, and pain predicted a decreased QoL.

Conclusion

Independent from psychiatric comorbidity and motor severity, fatigue appeared to be a primary NMS. Sleep‐related measures were highly associated with psychiatric comorbidity, but not with motor severity. Only NMS predicted HR‐QoL, which emphasizes the importance of attention to NMS in patients with CD.
Modeling and simulation of the motion of nanoparticles in cylindrical capillaries allowing particle‐to‐wall interactions
Authors: Mouffouk F. , Alrefae T. , Challa D. P. , Sini M.
Published: November 2016

The process of transporting nanoparticles at the blood vessels level stumbles upon various physical and physiological obstacles; therefore, a Mathematical modeling will provide a valuable means through which to understand better this complexity. In this paper, we consider the motion of nanoparticles in capillaries having cylindrical shapes (i.e., tubes of finite size). Under the assumption that these particles have spherical shapes, the motion of these particles reduces to the motion of their centers. Under these conditions, we derive the mathematical model, to describe the motion of these centers, from the equilibrium of the gravitational force, the hemodynamic force and the van der Waals interaction forces. We distinguish between the interaction between the particles and the interaction between each particle and the walls of the tube. Assuming that the minimum distance between the particles is large compared with the maximum radius R of the particles and hence neglecting the interactions between the particles, we derive simpler models for each particle taking into account the particles‐to‐wall interactions. At an error of order O(R) or O(R3)(depending if the particles are 'near' or 'very near' to the walls), we show that the horizontal component of each particle's displacement is solution of a nonlinear integral equation that we can solve via the fixed point theory. The vertical components of the displacement are computable in a straightforward manner as soon as the horizontal components are estimated. Finally, we support this theory with several numerical tests. Copyright © 2016 John Wiley & Sons, Ltd.
Using operational matrix for solving nonlinear class of mixed Volterra–Fredholm integral equations
Authors: Mirzaee Farshid , Hadadiyan Elham
Published: November 2016

This paper presents a computational technique for the solution of the nonlinear mixed Volterra–Fredholm integral equations of the second kind. Using the properties of three‐dimensional modification of hat functions, these are types of equations to a nonlinear system of algebraic equations. Also, convergence results and error analysis are discussed. The efficiency and accuracy of the proposed method is illustrated by numerical examples. Copyright © 2016 John Wiley & Sons, Ltd.
Fibroblast growth factor 10 markedly improves in vitro maturation of porcine cumulus‐oocyte complexes
Authors: Son Yeo‐Jin , Lee Seung‐Eun , Hyun Hyuk , Shin Min‐Young , Park Yun‐Gwi , Jeong Sang‐Gi , Kim Eun‐Young , Park Se‐Pill
Published: November 2016

Growth factors synthesized by ovarian somatic cells affect cumulus cell expansion and oocyte maturation in vitro. Fibroblast growth factor 10 (FGF10), for example, is a known regulator of mammalian cumulus‐oocyte complex maturation. In this study, we investigated the effects of 0, 5, 10, 50, and 100 ng/mL FGF10 (5F, 10F, 50F, and 100F, respectively) on in vitro cumulus cell expansion, oocyte maturation, and embryo development. The percentage of fully expanded cumulus cells at the oocyte's metaphase‐II (MII) stage was significantly higher in the 10F‐treated group than in the control. Transcript abundance of the cumulus cell expansion‐related gene encoding hyaluronian synthase 2 (HAS2) in cumulus cells at oocyte germinal vesicle breakdown (GVBD) was significantly higher in the 10F‐ and 50F‐treated groups compared to untreated controls, whereas the mRNA abundance of the protease cathepsin B (CTSB) at the oocyte MII stage was remarkably decreased in the 10F‐treated group. The percentage of oocytes with normal spindles was greater in the 10F‐ and 50F‐treated group at GVBD than in the other groups; the 5F‐, 10F‐, and 100F‐treated groups were higher than the control; and the 50F‐treated group was highest at MII. The abundance of GDF9 and BMP15 transcript at GVBD and BMP15 and CCNB1 transcripts at MII increased in the 10F‐treated group. Cleavage rate, blastocyst formation rate, and total cell number were significantly higher in the 5F‐ to 50F‐treated groups. These results demonstrate that FGF10 markedly improves cumulus cell expansion, oocyte maturation, and subsequent embryo development. Mol. Reprod. Dev. 84: 67–75, 2017. © 2016 Wiley Periodicals, Inc.
Ethylene Polymerization with a Hafnocene Dichloride Catalyst Using Trioctyl Aluminum and Borate: Polymerization Kinetics and Polymer Characterization
Authors: Mehdiabadi Saeid , Soares João B. P. , Brinen Jeffrey
Published: November 2016

The polymerization of ethylene is investigated in a semibatch solution reactor using bis(n‐propylcyclopentadienyl)hafnium dichloride catalyst and tetrakis(pentafluorophenyl) borate dimethylanilinium salt ([B(C6F5)4]−[Me2NHPh]+) as the catalytic system. Trioctylaluminum (TOA) is used as impurity scavenger and alkylating agent. Ethylene pressure, polymerization temperature, TOA, borate, and catalyst concentrations are changed to investigate ethylene polymerization kinetics with this catalyst system. A 23 central composite design, augmented with extra runs to further explore the effect of some factors, is used as the statistical basis for the polymerization study. Ethylene propagation follows first‐order kinetics. Chain transfer to monomer, β‐hydride elimination, and transfer to TOA are the main chain transfer reactions. In addition to alkylating the catalyst precursor, TOA also deactivates the catalyst. The mode of reactor addition for catalyst, borate, and TOA has also been studied. When TOA and borate are added sequentially to the reactor, followed by the catalyst, the polymerization activity is lower than when the catalyst and borate are added simultaneously, suggesting that complexation with borate avoids deactivation reactions with TOA.

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An original semi‐discrete approach to assess gas conductivity of concrete structures
Authors: Ezzedine El Dandachy M. , Briffaut M. , Dufour F. , Dal Pont S.
Published: November 2016

For civil engineering structures with a tightness role, structural permeability is a key issue. In this context, this paper presents a new proposition of a numerical modelling of leakage rate through a cracked concrete structure undergoing mode I cracking. The mechanical state of the material, considered in the framework of continuum mechanics based on finite element modelling, is described by means of the stress‐based nonlocal damage model which takes into account the stress state and provides realistic local mechanical fields. A semi‐discrete method based on the strong discontinuity approach to estimate crack opening is then considered in the post‐treatment phase. Using a Poiseuille's like relation, the coupling between the mechanical state of the material and its dry gas conductivity is performed.

For validation purposes, an original experimental campaign is conducted on a dry concrete disc loaded in a splitting setup. During the loading, gas conductivity and digital image correlation analysis are performed. The comparison with the 3D experimental mechanical global response highlights the performance of the mechanical model. The comparison between crack openings measured by digital image correlation and estimated by the strong discontinuity method shows a good agreement.

Finally, the results of the semi‐discrete approach coupled with the gas conductivity compared with experimental data show a good estimation of the structural conductivity. Consequently, if the mechanical problem is well modelled at the global scale, then the proposed approach provides good estimation of gas conductivity. Copyright © 2016 John Wiley & Sons, Ltd.
Penile compression clamps: A model of the internal mechanical state of penile soft tissues
Authors: Levy Ayelet , Fader Mandy , Bader Daniel , Gefen Amit
Published: November 2016

Aims

Prostate cancer is the most frequently diagnosed male cancer and urinary incontinence represents a major consequence following surgery. Penile compression clamps (PCCs) which externally occlude the urethra may be used to manage the incontinence. Despite potential complication of PCCs, such as deformation‐inflicted tissue damage, to date, there are no reported biomechanical criteria for design of PCCs, in terms of quantitative parameters for evaluating the safety‐versus‐efficacy of existing or future designs.

Methods

We developed a set of computational three‐dimensional models of the penis, to which compression was applied using five generic PCC designs. The internal mechanical states of the soft tissues of the penis were then analysed using finite element simulations.

Results

Stresses in skin, fat, and tunica albuginea regularly exceeded 10 kPa (75 mmHg). Cuff‐type and knurl‐type PCCs pose the highest potential risks to tissue health with elevated tissue stresses around the entire penile perimeter (cuff) or urethral stress concentrations (knurl). The soft and contoured PCCs produced the lowest values of these mechanical parameters.

Conclusions

The present study identified design characteristics, including envelopment, adaptability, and durability which provide the safest mechanical conditions in the penis and thus minimize the risk of tissue damage while still managing incontinence. Such data should help to design a safer clamp.
Development of a 7 T RF coil system for breast imaging
Authors: Kim Junghwan , Santini Tales , Bae Kyongtae Ty , Krishnamurthy Narayan , Zhao Yujuan , Zhao Tiejun , Ibrahim Tamer S.
Published: November 2016

In ultrahigh‐field MRI, such as 7 T, the signal‐to‐noise ratio (SNR) increases while transmit (Tx) field (B1+) can be degraded due to inhomogeneity and elevated specific absorption rate (SAR). By applying new array coil concepts to both Tx and receive (Rx) coils, the B1+ homogeneity and SNR can be improved. In this study, we developed and tested in vivo a new RF coil system for 7 T breast MRI.

An RF coil system composed of an eight‐channel Tx‐only array based on a tic‐tac‐toe design (can be combined to operate in single‐Tx mode) in conjunction with an eight‐channel Rx‐only insert was developed. Characterizations of the B1+ field and associated SAR generated by the developed RF coil system were numerically calculated and empirically measured using an anatomically detailed breast model, phantom and human breasts. In vivo comparisons between 3 T (using standard commercial solutions) and 7 T (using the newly developed coil system) breast imaging were made.

At 7 T, about 20% B1+ inhomogeneity (standard deviation over the mean) was measured within the breast tissue for both the RF simulations and 7 T experiments. The addition of the Rx‐only array enhances the SNR by a factor of about three. High‐quality MR images of human breast were acquired in vivo at 7 T. For the in vivo comparisons between 3 T and 7 T, an approximately fourfold increase of SNR was measured with 7 T imaging.

The B1+ field distributions in the breast model, phantom and in vivo were in reasonable agreement. High‐quality 7 T in vivo breast MRI was successfully acquired at 0.6 mm isotropic resolution using the newly developed RF coil system.
Developing a Framework to Evaluate the Potential of Global Learning in MOOCs
Authors: Mathews Sarah A. , Landorf Hilary
Published: November 2016

Massive Open Online Courses (MOOCs) have rapidly emerged as a new platform for online learning. Higher Education Institutions (HEIs) must now determine if MOOC courses should be accepted as course credit. The authors propose a framework for determining if a MOOC course helps students develop the 21st century skills promoted through global learning. This framework is centered on the conditions for global learning – i.e. a process of diverse people collaboratively analyzing and addressing problems that transcend borders – and facilitated through the Community of Inquiry (CoI) model. Any course that attends to these aspects should produce global learning outcomes that fall within one or more of the following three categories: learning about the world, learning with others, and learning to act.
Human Resource Development in Small Business: An Application of Brethower's Performance Principles to on the Job Training
Authors: Twyford Devon , Alagaraja Meera , Shuck Brad
Published: November 2016

Small businesses provide economic infrastructure in which communities develop and thrive and, in the United States alone, currently represent 99.7 percent of all employer firms. However, many small businesses fail to thrive past the first two years of establishment. Of the reasons small businesses fail, limited or non–existent employee training programs remains among the chief causes. The purpose of this paper is to explore the use of HRD within small businesses. Specifically on–the–job training was examined through the framework of Brethower's five performance principles in order to enhance the effectiveness of the on–the–job training approach.
Efficient hyper‐reduced‐order model (HROM) for thermal analysis in the moving frame
Authors: Zhang Yancheng , Combescure Alain , Gravouil Anthony
Published: November 2016

The hyper‐reduced‐order model (HROM) is proposed for the thermal calculation with a constant moving thermal load. Firstly, the constant velocity transient process is simplified to a steady‐state process in the moving frame. Secondly, the control volume is determined by the temperature rate, and the thermal equilibrium equation in the moving frame is derived by introducing an advective term containing the loading velocity. Thirdly, the HROM is performed on the control volume with a moving frame formulation. This HROM has been applied to the thermal loading on brick and ring disk specimens with a CPU gain of the order of 7 (107). In addition, two strategies are proposed for the HROM to improve its precision. Moreover, the high efficiency and high accuracy are kept for the parametric studies on thermal conductivity and amplitude of heat flux based on the developed HROM. Copyright © 2016 John Wiley & Sons, Ltd.
Assumed natural strain and stabilized quadrilateral Lobatto spectral elements for C0 plate/shell analysis
Authors: Sze K. Y. , Hu Y. C.
Published: November 2016

Lobatto elements are high order or spectral elements featured by non‐equispaced Lobatto nodes and the Lobatto nodal quadrature. The tensor product nature of the element interpolation allows the derivatives at the node be computed through the derivatives along the nodal line which involve only 1D interpolations. In this paper, generic schemes for formulating assumed natural strain and stabilized Lobatto Lagrange C0 plate/shell elements of order
2 are presented. Two assumed natural strain schemes are devised. Both schemes sample the normal membrane and transverse shear natural strain components at the 1D reduced‐order Gaussian quadrature points along the nodal lines. The difference is that the first and second schemes sample the membrane shear natural strain component at the Lobatto nodes and the 2D reduced‐order Gaussian quadrature points, respectively. Meanwhile, all the other natural strain components in both schemes can be obtained by 1D interpolation along the nodal lines. In the stabilization scheme for reduced‐integrated elements, only five stabilization vectors are required regardless of the element order. The new elements outperform the standard Lobatto element except when membrane‐dominated curved thin‐shell problems with strong boundary layer effect are considered by coarse meshes. Copyright © 2016 John Wiley & Sons, Ltd.
Stability and accuracy of three Fourier expansion‐based strong form finite elements for the free vibration analysis of laminated composite plates
Authors: Fantuzzi Nicholas , Tornabene Francesco , Bacciocchi Michele , Neves Ana M. A. , Ferreira Antonio J. M.
Published: November 2016

In the present paper, strong form finite elements are employed for the free vibration study of laminated arbitrarily shaped plates. In particular, the stability and accuracy of three different Fourier expansion‐based differential quadrature techniques are shown. These techniques are used to solve the partial differential system of equations inside each computational element. The three approaches are called harmonic differential quadrature, Fourier differential quadrature and improved Fourier expansion‐based differential quadrature methods. The improved Fourier expansion‐based differential quadrature method implements auxiliary functions in order to approximate functional derivatives up to the fourth order, with respect to the Fourier differential quadrature method that has a basis made of sines and cosines. All the present applications are related to literature comparisons and the presentation of new results for further investigation within the same topic. A study of such kind has never been proposed in the literature, and it could be useful as a reference for future investigation in this matter. Copyright © 2016 John Wiley & Sons, Ltd.
Age as a Risk Factor for Burnout Syndrome in Nursing Professionals: A Meta‐Analytic Study
Authors: Gómez‐Urquiza José L. , Vargas Cristina , De la Fuente Emilia I. , Fernández‐Castillo Rafael , Cañadas‐De la Fuente Guillermo A.
Published: November 2016

Although past research has highlighted the possibility of a direct relationship between the age of nursing professionals and burnout syndrome, results have been far from conclusive. The aim of this study was to conduct a wider analysis of the influence of age on the three dimensions of burnout syndrome (emotional exhaustion, depersonalization, and personal accomplishment) in nurses. We performed a meta‐analysis of 51 publications extracted from health sciences and psychology databases that fulfilled the inclusion criteria. There were 47 reports of information on emotional exhaustion in 50 samples, 39 reports on depersonalization for 42 samples, and 31 reports on personal accomplishment in 34 samples. The mean effect sizes indicated that younger age was a significant factor in the emotional exhaustion and depersonalization of nurses, although it was somewhat less influential in the dimension of personal accomplishment. Because of heterogeneity in the effect sizes, moderating variables that might explain the association between age and burnout were also analyzed. Gender, marital status, and study characteristics moderated the relationship between age and burnout and may be crucial for the identification of high‐risk groups. More research is needed on other variables for which there were only a small number of studies. Identification of burnout risk factors will facilitate establishment of burnout prevention programs for nurses. © 2016 Wiley Periodicals, Inc.
Impact of Individual and Neighborhood Factors on Cardiovascular Risk in White Hispanic and Non‐Hispanic Women and Men
Authors: Cohn Tanya , Miller Arlene , Fogg Louis , Braun Lynne T. , Coke Lola
Published: November 2016

Cardiovascular disease (CVD) is the leading cause of mortality for adults in the US, regardless of ethnicity. A cross‐sectional correlational design was used to describe and compare CVD risk and cardiac mortality in White Hispanic and non‐Hispanic women and men. Data from 3,317 individuals (1,523 women and 1,794 men) hospitalized for non‐cardiac causes during 2012–2013, and data from the 2010 United States Census were included. The sex‐specific 10‐year Framingham General Cardiovascular Risk Score (FRS‐10) was used to estimate long‐term risk for major cardiac events. Approximately three‐quarters of the sample was White Hispanic. FRS‐10 scores were generally low, but a high prevalence of risk factors not included in the standard FRS‐10 scoring formula was seen. White Hispanic women had significantly lower estimated CVD risk scores compared to White Hispanic and non‐Hispanic men despite higher non‐FRS‐10 risks. Neighborhood median household income had a significant negative relationship and Hispanic neighborhood concentration had a significant positive relationship with cardiac mortality. Hispanic concentration was the only predictor of estimated CVD risk in a multilevel model. CVD risk assessment tools that are calibrated for ethnic groups and socioeconomic status may be more appropriate for Hispanic individuals than the FRS‐10. Neighborhood‐level factors should be included in clinical cardiac assessment in addition to individual characteristics and behavioral risks. Researchers should continue to seek additional risk factors that may contribute to or protect against CVD in order to close the gap between estimated CVD risk and actual cardiac mortality for Hispanics in the US. © 2016 Wiley Periodicals, Inc.
Detection of Ligand‐induced Conformational Changes in the Activation Loop of Aurora‐A Kinase by PELDOR Spectroscopy
Authors: Burgess Selena G. , Grazia Concilio Maria , Bayliss Richard , Fielding Alistair J.
Published: November 2016

The structure of protein kinases has been extensively studied by protein crystallography. Conformational movement of the kinase activation loop is thought to be crucial for regulation of activity; however, in many cases the position of the activation loop in solution is unknown. Protein kinases are an important class of therapeutic target and kinase inhibitors are classified by their effect on the activation loop. Here, we report the use of pulsed electron double resonance (PELDOR) and site‐directed spin labeling to monitor conformational changes through the insertion of MTSL [S‐(1‐oxyl‐2,2,5,5‐tetramethyl‐2,5‐dihydro‐1 H‐pyrrol‐3‐yl)methyl methanesulfonothioate] on the dynamic activation loop and a stable site on the outer surface of the enzyme. The action of different ligands such as microtubule‐associated protein (TPX2) and inhibitors could be discriminated as well as their ability to lock the activation loop in a fixed conformation. This study provides evidence for structural adaptations that could be used for drug design and a methodological approach that has potential to characterize inhibitors in development.
Rice husk bio‐filler reinforced polymer blends of recycled HDPE/PET: Three‐dimensional stability under water immersion and mechanical performance
Authors: Chen Ruey Shan , Ahmad Sahrim , Gan Sinyee
Published: November 2016

Green composite materials were made from agricultural and plastic wastes which were rice husk (RH), recycled high‐density polyethylene (rHDPE), and recycled polyethylene terephthalate (rPET), by twin‐screw extrusion and hot/cold pressing molding. The dimensional stability, orthotropic swelling, and mechanical performance of the green composites were determined as a function of bio‐filler concentration for neat (uncompatibilized) and compatbilized rHDPE/rPET blend based composites. Water absorption and swelling results showed a linear increase with the RH concentration. The highest swelling occurred in the thickness of the composites, followed by the width and length, respectively. Water absorption and dimensional instability of compatibilized recycled polymer blend (rPB)‐based composites were lower than those of neat rPB‐based composites. As RH concentration increased, the flexural properties increased significantly. The optimum tensile strength and modulus were achieved at 70 wt% RH. It is interesting to note that compatibilization of polymer blend matrix had further increased the strength and elongation properties of composites. POLYM. COMPOS., 39:2695–2704, 2018. © 2016 Society of Plastics Engineers
Stress–strain model and design guidelines for CFRP‐confined circular reinforced concrete columns
Authors: Al‐Rousan Rajai Z. , Issa Mohsen A.
Published: November 2016

An analytical model is introduced in this paper to predict the stress–strain behavior of axially loaded circular reinforced concrete (RC) columns with internal longitudinal reinforcement and lateral ties confined by carbon fiber‐reinforced polymer (CFRP) composites. The proposed model is a two stage stress strain curve, with a second‐order polynomial in the first stage and a liner relationship with a reduced slope in the second stage. The model is an extension of the confinement model introduced by Richart et al. for confinement concrete. The model is based on the general mechanism of confinement, compatibility and equilibrium equations, and failure criteria of CFRP composites. The main parameters considered are the CFRP volumetric ratio (
), column size, and concrete compressive strength (
). The results predicted by the model were in good agreement with the results of current investigation and other proposed models of CFRP‐confined circular RC columns reported in the literature. In addition, based on the investigation results, new design guidelines were developed that can be effectively used to determine the ultimate confined axial stresses of a RC column. POLYM. COMPOS., 39:2722–2733, 2018. © 2016 Society of Plastics Engineers