bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen bonding interactions, crystallization, and surface hydrophobicity in nanostructured epoxy/block copolymer blends
Authors: Hameed Nishar , Guo Qipeng , Hanley Tracey , Mai Yiu‐Wing 
Published: February 2010

AbstractHydrogen bonding interactions, phase behavior, crystallization, and surface hydrophobicity in nanostructured blend of bisphenol A‐type epoxy resin (ER), for example, diglycidyl ether of bisphenol A (DGEBA) and poly(ε‐caprolactone)‐block‐poly(dimethyl siloxane)‐block‐poly(ε‐caprolactone) (PCL–PDMS–PCL) triblock copolymer were investigated by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, transmission electron microscopy, small‐angle X‐ray scattering, and contact angle measurements. The PCL–PDMS–PCL triblock copolymer consisted of two epoxy‐miscible PCL blocks and an epoxy‐immiscible PDMS block. The cured ER/PCL–PDMS–PCL blends showed composition‐dependent nanostructures from spherical and worm‐like microdomains to lamellar morphology. FTIR study revealed the existence of hydrogen bonding interactions between the PCL blocks and the cured epoxy, which was responsible for their miscibility. The overall crystallization rate of the PCL blocks in the blend decreased remarkably with increasing ER content, whereas the melting point was slightly depressed in the blends. The surface hydrophobicity of the cured ER increased upon addition of the block copolymer, whereas the surface free energy (γs) values decreased with increasing block copolymer concentration. The hydrophilicity of the epoxy could be reduced through blending with the PCL–PDMS–PCL block copolymer that contained a hydrophobic PDMS block. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 790–800, 2010
Viscoelastic interfacial properties of compatibilized poly(ε‐caprolactone)/polylactide blend
Authors: Wu Defeng , Zhang Yisheng , Yuan Lijuan , Zhang Ming , Zhou Weidong 
Published: February 2010

AbstractPoly(ε‐caprolactone)/polylactide blend (PCL/PLA) is an interesting biomaterial because the two component polymers show good complementarity in their physical properties. However, PCL and PLA are incompatible thermodynamically and hence the interfacial properties act as the important roles controlling the final properties of their blends. Thus, in this work, the PCL/PLA blends were prepared by melt mixing using the block copolymers as compatibilizer for the studies of interfacial properties. Several rheological methods and viscoelastic models were used to establish the relations between improved phase morphologies and interfacial properties. The results show that the interfacial behaviors of the PCL/PLA blends highly depend on the interface‐located copolymers. The presence of copolymers reduces the interfacial tension and emulsified the phase interface, leading to stabilization of the interface and retarding both the shape relaxation and the elastic interface relaxation. As a result, besides the relaxation of matrices (τm) and the shape relaxation of the dispersed PLA phase (τF), a new relaxation behavior (τβ), which is attribute to the relaxation of Marangoni stresses tangential to the interface between dispersed PLA phase and matrix PCL, is observed on the compatibilized blends. In contrast to that of the diblock copolymers, the triblock copolymers show higher emulsifying level. However, both can improve the overall interfacial properties and enhance the mechanical strength of the PCL/PLA blends as a result. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 756–765, 2010
Rheological properties of crystallizing polylactide: Detection of induction time and modeling the evolving structure and properties
Authors: Yuryev Yury , Wood‐Adams Paula 
Published: February 2010

AbstractLinear viscoelastic properties of polymer melts are highly sensitive to any structural changes, including molecular weight changes and the formation and growth of crystallites. Here, we make use of this sensitivity to study the homogeneous crystallization of polylactide. As this polymer is rather quickly susceptible to thermal degradation even at moderate temperatures, it is essentially impossible to study homogeneous crystallization in the absence of degradation. Thus, the evolution of complex viscosity of a polylactide due to thermal degradation in the absence of crystallization was studied. A simple empirical model is used to characterize the variation of complex viscosity due to thermal degradation and to determine the induction time of homogeneous crystallization at wide range of degrees of supercooling. Next, the evolution of complex viscosity due to crystallization was measured at several temperatures. Based on the results, a phenomenological model describing the viscosity evolution during homogeneous crystallization is proposed and validated. Finally, the linear viscoselastic data in the early stages of crystallization are shown to be consistent with gelation due to the formation of a network of tie molecules between spherulites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 812–822, 2010
Upregulation of L‐type Cav1 channels in the development of psychological dependence
Authors: Shibasaki Masahiro , Kurokawa Kazuhiro , Ohkuma Seitaro 
Published: February 2010

AbstractAlthough L‐type voltage‐dependent Ca2+channels regulate activity‐dependent processes including synaptic plasticity and synapse formation, there are few data on the changes of Cav1 channel expression in psychological dependence. This study investigated the role of L‐type Cav1 channel expression in the brain of mouse that was psychologically dependent on methamphetamine (2 mg/kg, subcutaneous injection [s.c.]), cocaine (10 mg/kg, s.c.), and morphine (5 mg/kg, s.c.) with the conditioned place preference paradigm. Intracerebroventricular administration of nifedipine (3, 10, and 30 nmol/mouse) dose‐dependently reduced the development of methamphetamine‐, cocaine‐, and morphine‐induced rewarding effect. Under such conditions, protein levels of both Cav1.2 and Cav1.3 in the frontal cortex and the limbic forebrain were significantly increased on methamphetamine‐, cocaine‐, and morphine‐induced psychologically dependent mice. These findings suggest that the upregulation of Cav1.2 and Cav1.3 participated in the development of psychological dependence. Synapse 64:440–444, 2010. © 2010 Wiley‐Liss, Inc.
Prenatal and postnatal exposure to bisphenol a induces anxiolytic behaviors and cognitive deficits in mice
Authors: Tian Yu‐Hua , Baek Joung‐Hee , Lee Seok‐Yong , Jang Choon‐Gon 
Published: February 2010

AbstractBisphenol A (BPA), an environmental endocrine‐disrupting chemical, has been extensively evaluated for reproductive toxicity and carcinogenicity. However, little is known about the behavioral and neurochemical effects of BPA exposure. This study examined whether chronic daily exposure to an environmental endocrine‐disrupting chemical, bisphenol A [(BPA); 100 μg/kg/day or 500 μg/kg/day, p.o.], from prenatal Day 7 to postnatal Day 36 would lead to changes in anxiety and memory in mice. First, we observed the behavioral alterations of BPA‐treated mice using two anxiety‐related models, the open field test and elevated plus maze (EPM) test. In the open field test, BPA treatment (100 μg/kg/day) increased movement in the central zone. BPA treatment (500 μg/kg/day) also increased the time spent in the open arms in the EPM test. Second, we measured cognitive ability in the Y‐maze test and novel object test. BPA‐treated mice showed decreased alternation behavior in the Y‐maze at both of doses, indicating working memory impairment. BPA‐treated mice (100 μg/kg/day) also showed decreased novel object recognition as expressed by central locomotion and frequency in the central zone, showing recognition memory impairment. Finally, to measure changes in the dopaminergic and NMDAergic systems in the brain, we performed autoradiographic receptor binding assays for dopamine D1 and D2 receptors, the NMDA receptor, and the dopamine transporter. BPA treatment increased D2 receptor binding in the caudate putamen (CPu) but decreased DAT binding. BPA treatment also decreased NMDA receptor binding in the frontal cortex and CA1, CA3, and DG of the hippocampus. Taken together, our results suggest that long‐term BPA exposure in mice can induce anxiolytic behaviors, cognitive deficits and changes in the dopaminergic and NMDAergic systems. Synapse 64:432–439, 2010. © 2010 Wiley‐Liss, Inc.
Scientific reasoning and epistemological commitments: Coordination of theory and evidence among college science students
Authors: Zeineddin Ava , Abd‐El‐Khalick Fouad 
Published: February 2010

AbstractReasoning skills are major contributors to academic and everyday life success. Epistemological commitments (ECs) are believed to underlie reasoning processes and, when considered, could do much in delineating the complex nature of scientific reasoning. This study examined the relationship between ECs and scientific reasoning among college science students. Prior knowledge (PK) was factored in as an intervening variable. Participants were 139 college students enrolled in two physics courses in a large Midwestern university. They completed an online questionnaire, which assessed their PK regarding buoyancy in liquids and EC to the consistency of theory with evidence. Responses to the online questionnaire were used to select 40 participants with varying levels of PK and EC. These participants were divided into four groups, each with 10 students, representing four conditions: High PK–High EC, High PK–Low EC, Low PK–High EC, and Low PK–Low EC. These groups allowed using a 2 × 2 factorial quasi‐experimental design to examine the relationship between participants' reasoning and ECs, accounting for their PK. The quality of participants' reasoning was assessed during individual interviews, which presented them with four problem‐solving tasks involving objects immersed in water. Two‐way analysis of variance (ANOVA) indicated the absence of interaction between PK and EC. The results showed that the higher the ECs were, the higher the quality of reasoning was for comparable levels of PK. Additionally, it was found that PK impacted reasoning more strongly when ECs were weaker. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 1064–1093, 2010
Junior high school physics: Using a qualitative strategy for successful problem solving
Authors: Mualem Roni , Eylon Bat Sheva 
Published: February 2010

AbstractStudents at the junior high school (JHS) level often cannot use their knowledge of physics for explaining and predicting phenomena. We claim that this difficulty stems from the fact that explanations are multi‐step reasoning tasks, and students often lack the qualitative problem‐solving strategies needed to guide them. This article describes a new instructional approach for teaching mechanics at the JHS level that explicitly teaches such a strategy. The strategy involves easy to use visual representations and leads from characterizing the system in terms of interactions to the design of free‐body force diagrams. These diagrams are used for explaining and predicting phenomena based on Newton's laws. The findings show that 9th grade students who studied by the approach advanced significantly from pretests to post‐tests on items of the Force Concept Inventory—FCI and on other items examining specific basic and complex understanding performances. These items focused on the major learning goals of the program. In the post‐tests the JHS students performed on the FCI items better than advanced high‐school and college students. In addition, interviews conducted before, during, and after instruction indicated that the students had an improved ability to explain and predict phenomena using physics ideas and that they showed retention after 6 months. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 1094–1115, 2010
Immigrant entrepreneurship: Scrutinizing a promising type of business venture
Authors: Chrysostome Elie , Lin Xiaohua 
Published: February 2010

AbstractImmigrant entrepreneurship is an important socioeconomic phenomenon today. In major destination countries for immigrants such as the United States, Canada, the United Kingdom, and Australia, immigrant entrepreneurship plays a critical role in economic development. The economic impact of immigrant entrepreneurship in the host country is well known, but the influence of immigrant entrepreneurship in the host country is not limited to its economic aspects. It includes important noneconomic effects such as the development of vibrant ethnic communities, social integration and recognition of immigrants, a nurturing entrepreneurial spirit, and providing role models for immigrants. From the management perspective, there are many aspects of immigrant entrepreneurship that are still unknown and need to be addressed. The purpose of this special issue is to shed light on some of those aspects. The articles selected to be published in this issue offer an excellent analysis of various important aspects of the topic, including the success factors of immigrant entrepreneurship, the influence of family networks, and the noneconomic effects of immigrant entrepreneurship. We believe the issue breaks new ground and offers excellent information on the topic. © 2010 Wiley Periodicals, Inc.
Noneconomic effects of ethnic entrepreneurship: A focused look at the Chinese and Korean enclave economies in Los Angeles
Authors: Zhou Min , Cho Myungduk 
Published: February 2010

AbstractIn this article, we aim to develop a conceptual framework from a community perspective to examine the noneconomic effects of ethnic entrepreneurship, paying close attention to the linkage between entrepreneurship and community building. We base our analysis on ethnographic data from our comparative case studies of the Chinese and Korean enclave economies in Los Angeles. We argue that it is the social embeddedness of entrepreneurship, rather than individual entrepreneurs per se, that creates a unique social environment conducive to upward social mobility. This study suggests that ethnic entrepreneurship plays a pivotal role in immigrant adaptation beyond observable economic gains. Policy implications are discussed. © 2010 Wiley Periodicals, Inc.
Immigrant business enterprises: A classification framework conceptualization and test
Authors: Curci Roberto , Mackoy Robert 
Published: February 2010

AbstractThis article proposes the Immigrant Business Enterprises Classification Framework to organize immigrant‐owned businesses into categories associated with different levels of business integration into a host country's mainstream business community. The article applies the framework and reports the findings of structured face‐to‐face interviews with 199 Hispanic business enterprises (HBEs) in Indianapolis. The authors find Hispanic‐owned businesses hold different characteristics depending upon the integration category in which they are classified; the findings suggest that to support immigrant entrepreneurship, governments, business development organizations, and researchers should address category‐specific challenges, opportunities, and needs. © 2010 Wiley Periodicals, Inc.
The diaspora solution to innovation capacity development: Immigrant entrepreneurs in the contemporary world
Authors: Lin Xiaohua 
Published: February 2010

AbstractThe international migration of highly skilled labor was formerly a threat to the underdeveloped world with regard to indigenous innovation capacity. However, certain countries have successfully turned “brain drain” into “brain gain” by effective engagement with a skilled diaspora who have returned to set up business ventures in the homeland. This article advocates an entrepreneurial approach to the development of national innovation capacity through contemporary diasporic entrepreneurship (CDE). Drawing evidence mostly from China, the article argues that (1) CDE offers an alternative to conventional indigenously and internationally oriented approaches toward innovation capacity development; (2) compared to other ways of diaspora homeland engagement, CDE is most beneficial to capacity development; and (3) besides participating in philanthropic and scientific projects, a skilled diaspora returning as private business owners represents an often more productive way of contributing to national capacity development. © 2010 Wiley Periodicals, Inc.
Relativistic invariance of dispersion‐relations and their associated wave‐operators and Green‐functions
Authors: Censor D. 
Published: February 2010

AbstractIdentifying invariance properties helps in simplifying calculations and consolidating concepts. Presently the Special Relativistic invariance of dispersion relations and their associated scalar wave operators is investigated for general dispersive homogeneous linear media. Invariance properties of the four‐dimensional Fourier‐transform integrals is demonstrated, from which the invariance of the scalar Green‐function is inferred. Dispersion relations and the associated group velocities feature in Hamiltonian ray tracing theory. The derivation of group velocities for moving media from the dispersion relation for these media at rest is discussed. It is verified that the group velocity concept satisfies the relativistic velocity‐addition formula. In this respect it is considered to be ‘real’, i.e., substantial, physically measurable, and not merely a mathematical artifact. Conversely, if we assume the group velocity to be substantial, it follows that the dispersion relation must be a relativistic invariant.
On the existence of solution in the linear elasticity with surface stresses
Authors: Altenbach H. , Eremeyev V.A. , Lebedev L.P. 
Published: February 2010

AbstractThe mathematical investigation of the initial‐boundary and boundary value problems in the linear elasticity considering surface stresses is presented. Weak setup of the problems based on mechanical variational principles is studied. Theorems of uniqueness and existence of the weak solution in energy spaces of static and dynamic problems are formulated and proved. Some properties of the spectrum of the problems under consideration are established. The studies are performed applying the functional analysis techniques. Finally, the Rayleigh principle for eigenfrequencies is constructed.
Structural comparison and consumer choice
Authors: Markman Arthur B. , Loewenstein Jeffrey 
Published: February 2010

AbstractPsychological research has demonstrated important parallels between the structural alignment process involved in judgments of similarity and the processes that are involved in analogical reasoning. Gradually, this work on comparisons was applied to consumer choice. In this paper, we review the influence of structural alignment on choices among a set of options. Then, we discuss extensions of this work to comparative advertising and to the role of analogy in marketing communication. Finally, we discuss important extensions to structural alignment suggested by this work such as the key role that affect plays in comparisons made during the choice process.
A Brief Review on the Mechanisms of miRNA Regulation
Authors: Cai Yimei , Yu Xiaomin , Hu Songnian , Yu Jun 
Published: February 2010

Abstract
MicroRNAs (miRNAs) are a class of short, endogenously-initiated non-coding RNAs that post-transcriptionally control gene expression via either translational repression or mRNA degradation. It is becoming evident that miRNAs are playing significant roles in regulatory mechanisms operating in various organisms, including developmental timing and host-pathogen interactions as well as cell differentiation, proliferation, apoptosis and tumorigenesis. Likewise, as a regulatory element, miRNA itself is coordinatively modulated by multifarious effectors when carrying out basic functions, such as SNP, miRNA editing, methylation and circadian clock. This mini-review summarized the current understanding of interactions between miRNAs and their targets, including recent advancements in deciphering the regulatory mechanisms that control the biogenesis and functionality of miRNAs in various cellular processes.
New fossils of Sirenia from the Middle Eocene of Navarre (Western Pyrenees): the oldest West European sea cow record
Authors: ASTIBIA H. , BARDET N. , PEREDA-SUBERBIOLA X. , PAYROS A. , DE BUFFRÉNIL V. , ELORZA J. , TOSQUELLA J. , BERRETEAGA A. , BADIOLA A. 
Published: February 2010

AbstractPostcranial remains of Sirenia from the early Middle Eocene (late Lutetian) Urbasa-Andia Formation of Navarre (Western Pyrenees) are described. The material consists of two partial atlas vertebrae, one humerus and several dorsal ribs (from Arrasate, Urbasa plateau), and partial dorsal ribs (from Lezaun, Andia plateau). The morphology of the fossils is consistent with referral to Dugongidae, the only sirenian clade known so far in the Middle Eocene of Europe. Moreover, the histological study of the ribs shows that the pachyosteosclerosis of extant Sirenia was definitively present by the early Middle Eocene. The oldest sirenian remains reported to date in the Pyrenean Realm were assigned to the Biarritzian, a regional stage that is currently ascribed either to the middle or to the lower–middle Bartonian. Therefore, the sirenian remains of Lezaun, reliably dated as late Lutetian (SBZ16 zone) in age, are definitively the earliest sirenian fossils known in Western Europe and are among the oldest sea cow records of Europe.
Laryngocoele as an unusual complication of supracricoid partial laryngectomy: evaluation of 62 cases
Authors: Naiboglu B , Aslan I , Oysu C , Zer Toros S , Durmus R , Egeli E 
Published: February 2010

AbstractBackground:This study sought to evaluate the incidence, aetiology, clinical features and treatment modalities for laryngocoele formation after supracricoid partial laryngectomy.Methods:The medical charts of 62 patients who had undergone supracricoid partial laryngectomy were reviewed.Results:Three patients developed laryngocoele, giving an incidence of 4.8 per cent. Two of these patients presented with a cervical mass, dyspnoea and fever. The mobility of the arytenoids was disturbed on the involved side. The third patient was admitted complaining only of a compressible cervical mass. In all patients, diagnosis was made by computed tomography scan. The transcervical surgical approach was preferred for resection.Conclusion:Laryngocoele can occur as a late complication of supracricoid partial laryngectomy. Remnants of the laryngeal ventricle may be the cause of laryngocoele formation. The integrity of the laryngeal ventricle in the resected specimen should be routinely checked in order to avoid this rare complication. Clinicians should be aware that, following supracricoid partial laryngectomy, a cervical mass presenting with dyspnoea and disturbance of arytenoid mobility does not always indicate tumour recurrence.
Relativistic filamentary equilibria
Authors: GEDALIN M. , SPITKOVSKY A. , MEDVEDEV M. , BALIKHIN M. , KRASNOSELSKIKH V. , VAIVADS A. , PERRI S. 
Published: February 2010

AbstractPlasma filamentation is often encountered in collisionless shocks and inertial confinement fusion. We develop a general analytical description of the two-dimensional relativistic filamentary equilibrium and derive the conditions for existence of potential-free equilibria. A pseudopotential equation for the vector-potential is constructed for cold and relativistic Maxwellian distributions. The role of counter-streaming is explained. We present single current sheet and periodic current sheet solutions, and analyze the equilibria with electric potential. These solutions can be used to study linear and nonlinear evolution of the relativistic filamentation instability.