bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and characterization of covalently functionalized graphene using vinyl‐terminated benzoxazine monomer and associated nanocomposites with low coefficient of thermal expansion
Authors: Ho Kuan‐Ku , Hsiao Min‐Chien , Chou Tsung‐Yu , Ma Chen‐Chi M , Xie Xiao‐Feng , Chiang Jen‐Chi , Yang Shih‐hsien , Chang Li‐Hsueh 
Published: October 2012

AbstractWe describe the preparation of vinyl‐terminated benzoxazine‐functionalized graphene using free radical grafting. The resulting functionalized graphene (f‐graphene) was incorporated into bis(3‐allyl‐3,4‐dihydro‐2H‐1,3‐benzoxazinyl)methane (V‐BF‐a) monomer in order that nanocomposites could be prepared. Results of scanning electron microscopy and transmission electron microscopy revealed that the sheets of f‐graphene were well dispersed throughout the matrix, and there was a strong interfacial interaction between the f‐graphene and polyV‐BF‐a. The inclusion of f‐graphene into the nanocomposites resulted in a material with a high thermal stability and a low coefficient of thermal expansion (CTE); increasing the content of f‐graphene reduced the CTE significantly more. A reduction in the CTE of up to 48% was produced by adding just 1 wt% of f‐graphene; this corresponded to an increase of 12 °C in the glass transition temperature. These results suggest that f‐graphene nanocomposites can be ‘tuned’ to give materials with both a low CTE and a high thermal stability, and that graphene composites of this type can thus be manufactured to withstand a wider range of temperatures.
Semibatch anionic ring‐opening polymerization of octamethylcyclotetrasiloxane in emulsions: effect of the amount of seed polymer particles
Authors: Mohorič Ines , Šebenik Urška 
Published: October 2012

AbstractSemibatch anionic ring‐opening polymerization of octamethylcyclotetrasiloxane with the use of seed polymer particles in emulsions was studied. The concentration of the emulsifier was set above the critical micelle concentration. We investigated the effect of the amount of seed polymer particles on the chemical kinetics and the average particle size and distribution. During monomer starving conditions the polymerization rate strongly depended on the monomer feed rate and not on the amount of seed particles. Throughout the entire monomer feed period the average particle size increased. This increase depended on the number and the size of seed particles. In emulsions with higher particle sizes higher equilibrium conversions were obtained. In our opinion, a greater extent of backbiting reactions is responsible for lower equilibrium conversions during and at the end of the process. The seeded semibatch process seems a reasonable choice for designing emulsion products with high monomer conversion and desired particle size. © 2012 Society of Chemical Industry
Determination of the optimum material parameters for intermediate band solar cells using diffusion model
Authors: Navruz Tugba Selcen , Saritas Muzeyyen 
Published: October 2012

ABSTRACTIn this study, the optimum material parameters capable of providing high efficiencies close to the detailed balance limit are determined for intermediate band solar cells. A diffusion model, including the overlap effect between absorption coefficients, is used during the calculations for the first time. It is obtained that to achieve high efficiencies close to the detailed balance limit; the effective density of state value, NCV, should be higher than 1017 cm−3 and the carrier mobility should be larger than 200 cm2/Vs, where the light concentration should not be higher than nearly 1000 sun. Besides, it is found out that the optimum intermediate band level and the base width depend on the mobility and effective density of state values. So they need to be optimized according to the material parameters. The effect of overlap between absorption coefficients on the performance of intermediate band solar cells is also investigated. Copyright © 2012 John Wiley & Sons, Ltd.
Preparation and characterization of pH‐responsive and thermoresponsive hybrid microgel particles with gold nanorods
Authors: Khan Aslam , Alhoshan Mansour 
Published: October 2012

AbstractWe report on pH‐responsive and thermoresponsive hybrid materials based on the assembly of gold nanorods, Au NRs, into multiresponsive, crosslinked copolymer microgel particles. These microgel particles were prepared by the surfactant‐free emulsion polymerization of N‐isopropylacrylamide and acrylic acid using N, N′‐methylene bis‐acrylamide as a crosslinker, which produces particles measuring approximately 160 nm that are interconnected to one other. Cetyltrimethyl ammonium bromide‐stabilized Au NRs were also prepared independently using a seed‐mediated growth method and then loaded into swollen, deprotonated, acrylic acid‐containing microgel particles using the electrostatic interactions between the oppositely charged particles. Transmission electron micrographs of the as‐prepared hybrid Au NR–microgel particles confirmed that the Au NRs were attached to the surface of the microgel particles. The size‐dependent temperature‐responsive characteristics of the hybrid microgel particles were studied by dynamic light scattering, and it was found that as the temperature increased across the phase transition temperature, the particle size decreased to 56% of the original volume. The thermoresponsive and pH‐responsive optical properties of the hybrid microgel particles were also systematically investigated. The thermo‐ and pH‐induced shrinkage of the microgel led to an increase in the UV–vis absorption intensity and caused a significant blue shift in the longitudinal surface plasmon bands of the Au NRs. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Polymer micromixers bonded to thermoplastic films combining soft‐lithography with plasma and aptes treatment processes
Authors: Lee Michael , Lopez‐Martinez Maria J. , Baraket Abdellatif , Zine Nadia , Esteve Jaume , Plaza Jose A. , Jaffrezic‐Renault Nicole , Errachid Abdelhamid 
Published: October 2012

AbstractOver the past few years, a growing interest on covalent bonding of polydimethylsiloxane (PDMS) microfluidic devices to thermoplastic films has developed due to reduced costs, biocompatibility, and flexibility. The silane reagent, 3‐aminopropyltriethoxysilane (APTES) has been applied to create this bonding. Here, we report on the fabrication of replica PDMS micromixer devices from a silicon mold using soft lithography that is rapid, facile, and cost‐effective to manufacture. After replica molding, the PDMS micromixer devices were bonded to the APTES‐activated thermoplastic films of polyimide, polyethylene terephthalate, and polyethylene naphthalate. Characterization of these thermoplastic surfaces was analyzed by contact angle measurement, surface free energy, and X‐ray photoelectron spectroscopy. To demonstrate the functionality of this technology, we have analyzed the PDMS micromixers by a peel test, nonleakages, and mixing with the injection of inks, a surfactant, and varying pH solutions. To our knowledge, this is the first reported example in literature of the PDMS–APTES–thermoplastic films preparation that integrates a complex micromixer device. Here, we have established that the hydrophobicity of both sealed polymers required alteration in order for dispersion of a polar liquid in the mixing loops. The application of a polar solvent before injection can remedy this ill effect formulating a hydrophilic micromixer. These preliminary results demonstrate the feasibility of the fabrication technology, bonding technique, and application of the micromixer that, once optimized, can eventually integrate more components to formulate a lab‐on‐a‐chip with the fabrication of gold microelectrodes for biological analysis of blood or plasma. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
A systematic review and meta‐analysis of psychosocial interventions for couples coping with cancer
Authors: Badr Hoda , Krebs Paul 
Published: October 2012

AbstractObjectiveQuality of life (QOL) is a multidimensional construct that includes physical, psychological, and relationship well‐being.MethodsWe conducted a systematic review and meta‐analysis of randomized controlled studies published between 1980 and 2012 of interventions conducted with both cancer patients and their partners that were aimed at improving QOL. Using bibliographic software and manual review, two independent raters reviewed 752 articles with a systematic process for reconciling disagreement, yielding 23 articles for systematic review and 20 for meta‐analysis.ResultsMost studies were conducted in breast and prostate cancer populations. Study participants (N = 2645) were primarily middle aged (mean = 55 years old) and white (84%). For patients, the weighted average effect size (g) across studies was 0.25 (95% CI = 0.12–0.32) for psychological outcomes (17 studies), 0.31 (95% CI = 0.11–0.50) for physical outcomes (12 studies), and 0.28 (95% CI = 0.14–0.43) for relationship outcomes (10 studies). For partners, the weighted average effect size was 0.21 (95% CI = 0.08–0.34) for psychological outcomes (12 studies) and 0.24 (95% CI = 0.6–0.43) for relationship outcomes (7 studies).ConclusionTherefore, couple‐based interventions had small but beneficial effects in terms of improving multiple aspects of QOL for both patients and their partners. Questions remain regarding when such interventions should be delivered and for how long. Identifying theoretically based mediators and key features that distinguish couple‐based from patient‐only interventions may help strengthen their effects on patient and partner QOL. Copyright © 2012 John Wiley & Sons, Ltd.
Psychosocial impact of lymphedema: a systematic review of literature from 2004 to 2011
Authors: Fu Mei R. , Ridner Sheila H. , Hu Sophia H. , Stewart Bob R. , Cormier Janice N. , Armer Jane M. 
Published: October 2012

AbstractObjectiveThis systematic review aimed to evaluate the level of evidence of contemporary peer‐reviewed literature published from 2004 to 2011 on the psychosocial impact of lymphedema.MethodsEleven electronic databases were searched and 1311 articles retrieved; 23 met inclusion criteria. Twelve articles utilized qualitative methodology and 11 used quantitative methodology. An established quality assessment tool was used to assess the quality of the included studies.ResultsThe overall quality of the 23 included studies was adequate. A critical limitation of current literature is the lack of conceptual or operational definitions for the concept of psychosocial impact. Quantitative studies showed statistically significant poorer social well‐being in persons with lymphedema, including perceptions related to body image, appearance, sexuality, and social barriers. No statistically significant differences were found between persons with and without lymphedema in the domains of emotional well‐being (happy or sad) and psychological distress (depression and anxiety). All 12 of the qualitative studies consistently described negative psychological impact (negative self‐identity, emotional disturbance, and psychological distress) and negative social impact (marginalization, financial burden, perceived diminished sexuality, social isolation, perceived social abandonment, public insensitivity, and non‐supportive work environment). Factors associated with psychosocial impact were also identified.ConclusionsLymphedema has a negative psychosocial impact on affected individuals. The current review sheds light on the conceptualization and operationalization of the definitions of psychosocial impact with respect to lymphedema. Development of a lymphedema‐specific instrument is needed to better characterize the impact of lymphedema and to examine the factors contributing to these outcomes in cancer and non‐cancer‐related populations. Copyright © 2012 John Wiley & Sons, Ltd.
Experimental support for the foldability–function tradeoff hypothesis: Segregation of the folding nucleus and functional regions in fibroblast growth factor‐1
Authors: Longo Liam , Lee Jihun , Blaber Michael 
Published: October 2012

AbstractThe acquisition of function is often associated with destabilizing mutations, giving rise to the stability–function tradeoff hypothesis. To test whether function is also accommodated at the expense of foldability, fibroblast growth factor‐1 (FGF‐1) was subjected to a comprehensive φ‐value analysis at each of the 11 turn regions. FGF‐1, a β‐trefoil fold, represents an excellent model system with which to evaluate the influence of function on foldability: because of its threefold symmetric structure, analysis of FGF‐1 allows for direct comparisons between symmetry‐related regions of the protein that are associated with function to those that are not; thus, a structural basis for regions of foldability can potentially be identified. The resulting φ‐value distribution of FGF‐1 is highly polarized, with the majority of positions described as either folded‐like or denatured‐like in the folding transition state. Regions important for folding are shown to be asymmetrically distributed within the protein architecture; furthermore, regions associated with function (i.e., heparin‐binding affinity and receptor‐binding affinity) are localized to regions of the protein that fold after barrier crossing (late in the folding pathway). These results provide experimental support for the foldability–function tradeoff hypothesis in the evolution of FGF‐1. Notably, the results identify the potential for folding redundancy in symmetric protein architecture with important implications for protein evolution and design.
Spammers operations: a multifaceted strategic analysis
Authors: Thonnard O. , Vervier Pierre‐Antoine , Dacier M. 
Published: October 2012

AbstractThere is a consensus in the anti‐spam community regarding the prevalence of spam botnets and the significant role they play in the worldwide spam problem. Nevertheless, far less attention has been devoted to studying the strategic behavior of spammers on a long‐term basis. This paper explores several facets of spammers operations by providing three essential perspectives: (i) we study the inter‐relationships among spam botnets through their aggregate spam campaigns, and we focus on identifying similarities or differences in their modus operandi; (ii) we look at the impact of the Rustock takedown on the botnet ecosystem; and (iii) we study the conjecture about spammers hijacking unused IP space to send spam in a stealthy way. To that end, we have analyzed over one million spam records collected by Symantec.cloud (formerly MessageLabs) through worldwide distributed spamtraps. Our methodology leverages techniques relying on data fusion and multi‐criteria decision analysis to extract intelligence from large spam data sets by automatically correlating spam campaigns according to various combinations of spam features. We also take advantage of node–link visualizations developed in the context of VIS‐SENSE, a research project aiming at developing Visual Analytics technologies for the security domain. Using these visualizations, we illustrate the tight relationships that exist among different botnet families (such as Rustock/Grum or Lethic/Maazben). Regarding the disruption of Rustock on 17 March 2011, our experimental results provide substantial evidence indicating that part of the botnet activity may have been offloaded to Grum shortly after the takedown operation. Finally, we analyzed over 1 year of spam data enriched with Border Gateway Protocol data and found that an increasing amount of spam may have been sent from IP blocks hijacked for several weeks or months, even though this phenomenon remains marginal at this time compared with spam sent from large botnets. Copyright © 2012 John Wiley & Sons, Ltd.
Molecular structure of a random copolymer film by plasma‐enhanced CVD from a mixture of cyclohexa hydrocarbons
Authors: Moriki Kazunori , Yumoto Motoshige 
Published: October 2012

AbstractAn important issue in the polymerization of a polymer film by plasma‐enhanced chemical vapor deposition (PECVD) is how to control the polymer structure. As is generally recognized, it is extremely difficult to control the process because it is very complex. For example, various precursors in the plasma arise from fragmentation of source monomers, which can easily change by varying the plasma conditions. High‐energy electrons and ions in the plasma bombard the surface of the deposited film and affect the chemical reaction on the film. Moreover, the droplets that arise from the reactor wall by sputtering will accumulate on the film. However, if we aim to fabricate only a photonically functional polymer film, we will be able to find a solution. In this paper, we propose copolymerization from two types of monomers; one type is used as jointing materials by cracking, and the other is used as a photonic functional segment without serious deformation. This difference of action arises from a difference in the formation enthalpy. To confirm this idea, as an initial step, we copolymerized a film from a mixture of benzene (C6H6) as the functional segment and cyclohexene (C6H10) as the jointing material under the low radio frequency power. The deposited film consists of sp2 bonding clusters surrounded by sp3 bonded (alkyl) networks. We confirmed that the sp2 bonding clusters mostly belong to phenyl, with a few belonging to olefins arising from decomposed C6H6. In addition, the amount of sp2 bonding increases proportionally with increasing ratio of C6H6 in the mixture, and the ratio of phenyl in the film becomes comparable to that of polystyrene. From these facts, we speculate that C6H10 acts as the jointing material and C6H6 as the functional segment. Additionally, we introduced tetrafluorocarbon (CF4) to the plasma. CF4 decomposes with a smaller energy than C6H10, and it forms mainly fluorine and CF3 radicals. The fluorine radical pulls out hydrogen from the film and reacts to form dangling bonds in the film. Moreover, we speculate that they will terminate the dangling bonds. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
MoS2/ta‐C‐Kombinationsschichten hergestellt durch Laser‐Arc‐Technologie
Authors: Weihnacht Volker , Brückner Andreas , Theiler Géraldine , Gradt Thomas 
Published: October 2012

AbstractMittels lasergesteuerter gepulster Vakuumbogentechnologie (Laser‐Arc) wurde eine reihe von reinen MoS2‐Schichten sowie Kombinationsschichten aus MoS2 und tetraedrischem amorphen Kohlenstoff (ta‐C) hergestellt. Mit diesen Schichtvarianten erfolgten tribologische Tests im Vakuum sowie in Atmosphäre. Dabei wurden im Hochvakuum reibungskoeffizienten bis zu 0,005 gemessen. Durch die Verwendung einer ta‐C unterschicht konnte eine Lebensdauer von über 5×105 Lastzyklen erreicht werden. Zudem erwies sich diese unterschicht als vorteilhaft für das tribologische Verhalten der MoS2/ta‐C Schichten unter atmosphärischen Bedingungen.
Innovativer Bayard‐Alpert Sensor mit ausgetrickster Röntgengrenze
Authors: von Freyhold Nikolas , Walter Marco , Wunderlich Heiko , Iwicki Jaroslaw , Flämmich Michael , Bergner Ute 
Published: October 2012

AbstractIn diesem Beitrag werden einige Probleme für die Nutzer von Bayard‐Alpert (BA) Totaldrucksensoren an UHV‐ und XHV‐Anlagen hinsichtlich Messbereich, Genauigkeit und Reproduzierbarkeit diskutiert. Unter anderem zeigen BA‐Sensoren, bedingt durch ihre Bauweise, einen geringen Fehlerstrom, der die untere Messgrenze des Sensors bestimmt. Aus der Betrachtung der grundlegenden physikalischen Prozesse, die zu diesem Reststrom in BA‐Sensoren beitragen, wird ein innovativer Ansatz abgeleitet, um die Restströme in BA‐Sensoren durch Nutzung physikalischer Effekte direkt im Sensor zu kompensieren. Experimentelle Ergebnisse eines neuen BA‐Sensors mit Reststromkompensation (BARION® XHV) zeigen, dass der Messbereich gegenüber konventionellen BA‐Sensoren um rund zwei Druckdekaden bis ins XHV erweitert und die Genauigkeit im Druckbereich 10−9…10−11 mbar deutlich verbessert wurde. Durch ein entsprechendes Design konnte darüber hinaus eine erhöhte Reproduzierbarkeit sichergestellt werden.
The Caenorhabditis elegans intestine
Authors: McGhee James D. 
Published: October 2012

AbstractThe transcriptional regulatory hierarchy that controls development of the Caenorhabditis elegans endoderm begins with the maternally provided SKN‐1 transcription factor, which determines the fate of the EMS blastomere of the four‐cell embryo. EMS divides to produce the posterior E blastomere (the clonal progenitor of the intestine) and the anterior MS blastomere, a major contributor to mesoderm. This segregation of lineage fates is controlled by an intercellular signal from the neighboring P2 blastomere and centers on the HMG protein POP‐1. POP‐1 would normally repress the endoderm program in both E and MS but two consequences of the P2‐to‐EMS signal are that POP‐1 is exported from the E‐cell nucleus and the remaining POP‐1 is converted to an endoderm activator by complexing with SYS‐1, a highly diverged β‐catenin. In the single E cell, a pair of genes encoding small redundant GATA‐type transcription factors, END‐1 and END‐3, are transcribed under the combined control of SKN‐1, the POP‐1/SYS‐1 complex, as well as the redundant pair of MED‐1/2 GATA factors, themselves direct zygotic targets of SKN‐1 in the EMS cell. With the expression of END‐1/END‐3, the endoderm is specified. END‐1 and END‐3 then activate transcription of a further set of GATA‐type transcription factors that drive intestine differentiation and function. One of these factors, ELT‐2, appears predominant; a second factor, ELT‐7, is partially redundant with ELT‐2. The mature intestine expresses several thousand genes, apparently all controlled, at least in part, by cis‐acting GATA‐type motifs. WIREs Dev Biol 2013, 2:347–367. doi: 10.1002/wdev.93For further resources related to this article, please visit the WIREs website.
Gadolinium‐based contrast agents for magnetic resonance cancer imaging
Authors: Zhou Zhuxian , Lu Zheng‐Rong 
Published: October 2012

AbstractMagnetic resonance imaging (MRI) is a clinical imaging modality effective for anatomical and functional imaging of diseased soft tissues, including solid tumors. MRI contrast agents (CA) have been routinely used for detecting tumor at an early stage. Gadolinium‐based CA are the most commonly used CA in clinical MRI. There have been significant efforts to design and develop novel Gd(III) CA with high relaxivity, low toxicity, and specific tumor binding. The relaxivity of the Gd(III) CA can be increased by proper chemical modification. The toxicity of Gd(III) CA can be reduced by increasing the agents' thermodynamic and kinetic stability, as well as optimizing their pharmacokinetic properties. The increasing knowledge in the field of cancer genomics and biology provides an opportunity for designing tumor‐specific CA. Various new Gd(III) chelates have been designed and evaluated in animal models for more effective cancer MRI. This review outlines the design and development, physicochemical properties, and in vivo properties of several classes of Gd(III)‐based MR CA tumor imaging. WIREs Nanomed Nanobiotechnol 2013, 5:1–18. doi: 10.1002/wnan.1198This article is categorized under:

Diagnostic Tools > Biosensing
Diagnostic Tools > In Vivo Nanodiagnostics and Imaging
Alternative Synthesis and Structures of C‐monoacetylenic Phosphaalkenes
Authors: Orthaber Andreas , Öberg Elisabet , Jane Reuben T. , Ott Sascha 
Published: October 2012

AbstractAn alternative synthesis of C‐monoacetylenic phosphaalkenes trans‐Mes*P=C(Me)(C≡CR) (Mes* = 2, 4, 6‐tBu3Ph, R = Ph, SiMe3) from C‐bromophosphaalkenes cis‐Mes*P=C(Me)Br using standard Sonogashira coupling conditions is described. Crystallographic studies confirm cis‐trans isomerization of the P=C double bond during Pd‐catalyzed cross coupling, leading exclusively to trans‐acetylenic phosphaalkenes. Crystallographic studies of all synthesized compounds reveal the extend of π‐conjugation over the acetylene and P=C π‐systems.