bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recent advance on constitutive models of thermal‐sensitive shape memory polymers
Authors: Zhang Qiang , Yang Qing‐Sheng 
Published: August 2011

AbstractShape memory polymers (SMPs) are a novel class of shape memory materials which can store a deformed (temporary) shape and recover an original (permanent) shape under a shape memory thermomechanical loading–unloading cycle. The deformation mechanisms of SMPs are very complicated, but the SMPs also have a lot of advantages and the widespread application value and prospect. So developing proper constitutive models that describe thermomechanical properties of SMPs and the shape memory effect is very challenging and of great theoretical and application value. Based on the deformation mechanisms and considerable experimental investigations of SMPs, researchers have developed many constitutive models. This article investigates the deformation mechanism and introduces the recent research advance of the constitutive models of thermal‐sensitive SMPs. Special emphases are given on the micromechanical constitutive relations in which the deformation is considered being based on the microstructure of the SMPs. Finally, the lack of research and prospects for further research are discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Wheat gluten fractions as wood adhesives—glutenins versus gliadins
Authors: Nordqvist Petra , Thedjil Dalia , Khosravi Sara , Lawther Mark , Malmström Eva , Khabbaz Farideh 
Published: August 2011

AbstractPlant proteins, such as wheat gluten, constitute attractive raw materials for sustainable wood adhesives. In this study, alkaline water dispersions of the protein classes of wheat gluten, glutenin, and gliadin were used as adhesives to bond together wood substrates of beech. The aim of the study is to measure the tensile shear strength of the wood substrates to compare the adhesive performance of glutenin and gliadin and to investigate the influence of application method and penetration of the dispersions into the wood material. A sodium hydroxide solution (0.1M) was used as dispersing and denaturing agent. Dispersions with different protein concentrations and viscosities were used, employing wheat gluten dispersions as references. Two different application methods, a press temperature of 110°C and a press time of 15 min, were employed. The tensile shear strength and water resistance of the wood substrates were compared, using a slightly modified version of the European Standard EN 204. The bond lines of the substrates were examined by optical microscopy to study the penetration and bond‐line thickness. The results reveal that the adhesive properties of gliadin are inferior to that of both glutenin and wheat gluten, especially in terms of water resistance. However, the tensile shear strength and the water resistance of gliadin are significantly improved when over‐penetration of the protein into the wood material is avoided, rendering the adhesive performance of gliadin equal to that of glutenin and wheat gluten. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Redox initiated free radical polymerization of 4‐methylstyrene
Authors: Mortamet Anne‐Cecile , Pethrick Richard A. 
Published: August 2011

AbstractStudies of the thermally initiated polymerization of 4‐methylstyrene using alkylperoxide in conjunction with cobalt and tertiary amine catalysts are reported. Addition of cobalt salts leads to a facile low temperature initiation of the polymerization process. The polymerization process was investigated using differential scanning calorimetry [DSC] and vibrating probe rheological measurements. Color changes which occur when the cobalt complex and peroxide are combined were studied using UV‐visible spectroscopy. The kinetics of polymerization was investigated using two different cobalt complexes. The initiation step in the polymerization is the conversion of the cobalt (II) to cobalt (III). The presence of the tertiary amine does not affect the oxidation state of the cobalt complex. The cobalt (III) complex gives a better rate of conversion than the cobalt (II) complex. The polymerization process is discussed in terms of redox reaction between the cobalt complex and the alkyperoxide. At low temperatures, the rate of conversion obeys simple Arrhenius kinetics. At higher temperatures the effects of gelation and catalysts inhibition influence the polymerization process. The polymerization process is sensitive to the level of available oxygen during the initiation step and inhibition by aldehyde is observed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Novel acetylene‐terminated polyisoimides with excellent processability and properties comparison with corresponding polyimides
Authors: Zhou Heng , Liu Feng , Zhang Yongsheng , Fan Weifeng , Liu Jingfeng , Wang Zhen , Zhao Tong 
Published: August 2011

AbstractTwo novel acetylene‐terminated isoimide oligomers and their corresponding imide oligomers have been synthesized by using trifluoroacetic anhydride or acetic anhydride as dehydrating agent, respectively. Their main structure was confirmed by Fourier transform infrared spectroscopy (FTIR). The isoimide oligomers were amorphous and showed excellent solublility in many common solvents, such as acetone and tetrahydeofuran, whereas the imide oligomers cannot dissolve in them. Differential scanning calorimetry and rheometer were used to study crosslinking behavior and processability of these oligomers. The isoimide oligomers exhibited considerably wider processing window and lower viscosity compared with imide ones. As expected, the isoimide form could be converted to imide form through thermal treatment, which could be demonstrated by FTIR. After the oligomers were cured, the polyisoimides showed similar properties compared with corresponding polyimides. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Assessment of Decision‐making Competence in Preadolescence
Authors: Weller Joshua A. , Levin Irwin P. , Rose Jason P. , Bossard Elaine 
Published: August 2011

ABSTRACTRecent research using late adolescent (18–19 years) and adult samples suggests that within‐subject performance on a variety of standard, controlled laboratory tasks reflects a higher‐order positive manifold of decision‐making competence. The present paper extends this important work by testing whether preadolescent children (10‐ to 11‐year‐olds, n = 101) exhibit a similar structural pattern characterizing their decision‐making performance. Performance on “child‐friendly” versions of framing problems, decision matrices, consistency in risk perceptions, and calibration of confidence conformed to a one‐factor solution, comparable with that previously found with older populations. Further, individual differences in effortful control, a temperament dimension related to self‐regulative executive function, was significantly associated with decision‐making competence. Importantly, these measures were predictive of both positive (e.g., completing set goals) and negative behaviors (e.g., missing homework assignments). Results are discussed in terms of the existence of early stable patterns of decision making and rationality and the emergence of systematic individual difference factors in decision making. Copyright © 2011 John Wiley & Sons, Ltd.
Exosome nanotechnology: An emerging paradigm shift in drug delivery
Authors: Lakhal Samira , Wood Matthew J.A. 
Published: August 2011

AbstractThe demonstration that dendritic cell (DC)‐derived exosomes can be exploited for targeted RNAi delivery to the brain after systemic injection provides the first proof‐of‐concept for the potential of these naturally occurring vesicles as vehicles of drug delivery. As well as being amenable to existing in vivo targeting strategies already in use for viruses and liposomes, this novel approach offers the added advantages of in vivo safety and low immunogenicity. Fulfilment of the potential of exosome delivery methods warrants a better understanding of their biology, as well as the development of novel production, characterisation, targeting and cargo‐loading nanotechnologies. Ultimately, exosome‐mediated drug delivery promises to overcome important challenges in the field of therapeutics, such as delivery of drugs across otherwise impermeable biological barriers, such as the blood brain barrier, and using patient‐derived tissue as a source of individualised and biocompatible therapeutic drug delivery vehicles.
Effect of HER2 status on risk of recurrence in women with small, node-negative breast tumours
Authors: Tanaka K , Kawaguchi H , Nakamura Y , Taguchi K , Nishiyama K , Ohno S 
Published: August 2011

Abstract

Background
Adjuvant trastuzumab for small, node-negative, human epidermal growth factor receptor 2 (HER2)-positive breast cancer remains controversial. The purpose of this study was to investigate the risk of recurrence in women with pathological tumour node (pTN) T1 N0 tumours.

Methods
Patients with pT1 N0 breast cancer diagnosed at the National Kyushu Cancer Centre between 2001 and 2007 were reviewed. Patients were categorized according to HER2 status.

Results
Four hundred and fifty-four patients who had pT1 N0 tumours, and had not received adjuvant trastuzumab, were identified. The HER2-negative and -positive groups comprised 376 and 78 patients (17·2 per cent) respectively. At a median follow-up of 46·3 months, there were 18 recurrences. The 5-year relapse-free survival (RFS) rates were 97·2 and 88 per cent in the HER2-negative and -positive groups respectively (P &lt; 0·001). Multivariable analysis identified HER2-positive tumour as an independent predictor of RFS in patients with pT1 N0 tumours (hazard ratio 6·65, 95 per cent confidence interval 2·53 to 17·49; P &lt; 0·001).

Conclusion
Women with pT1 N0 HER2-positive breast cancer have a high risk of recurrence.
Persuasive design: Putting it to use
Authors: Whalen John 
Published: August 2011

AbstractEditor's SummaryThe fundamental goal of information architecture is to stimulate change in a user's behavior or attitude. By applying psychological principles to site design, information architects can lead site visitors through stages of engagement to action. Persuasion starts with likeability and an uncomplicated invitation to continue to explore with minimal commitment. The design must be aesthetically appealing and appropriate for the audience. A sense of intrigue, connection with others and the potential for enhanced self image add to the allure. Having confidence in the source, overcoming any reason not to act and having an easy path to action enable the user to take the final psychological steps toward persuasion. Groupon and LivingSocial illustrate the effectiveness of these persuasive principles, which can readily be applied to virtually any website design.
Biodiversity informatics
Authors: Heidorn P. Bryan 
Published: August 2011

AbstractEditor's SummaryFor millennia, information about biological diversity has been collected as a way to understand the living world. The information record has evolved from early papyrus to modern electronic collections, but challenges to information access persist, despite and partly due to a variety of digital techniques and applications. Information exchange is hampered by lack of access to previous work, inconsistent naming, changes over time and insufficient resources to create comprehensive databases supporting federated search with Darwin Core metadata. With progress in biodiversity informatics, we will see greater use of DNA barcoding and metagenomic techniques to describe species, remote sensing tools and geographic information systems to detect and describe species' locations and movements and to identify habitats and environmental conditions. Biodiversity informatics provides essential scientific knowledge to better understand global ecosystems and to inform land use and policy decisions.
Facile Hydrogenation of Ketones Catalyzed by Platinum on Carbon under Ordinary Pressures and Temperatures
Authors: Fujiwara Yuta , Iwasaki Youhei , Maegawa Tomohiro , Monguchi Yasunari , Sajiki Hironao 
Published: August 2011

AbstractAn efficient and practical procedure for the hydrogenation of aliphatic and aromatic ketones under mild reaction conditions is established. The method is highly effective even for the hydrogenation of sterically hindered ketones. Furthermore, the selective hydrogenation of the carbonyl group of aromatic ketones was achieved with the aromatic nuclei and the resulting secondary benzyl alcohol moiety still intact on addition of catalytic amount of pyridine.
Rational Design, Synthesis, and Spectroscopic and Photophysical Properties of a Visible‐Light‐Excitable, Ratiometric, Fluorescent Near‐Neutral pH Indicator Based on BODIPY
Authors: Boens Noël , Qin Wenwu , Baruah Mukulesh , De Borggraeve Wim M. , Filarowski Aleksander , Smisdom Nick , Ameloot Marcel , Crovetto Luis , Talavera Eva M. , Alvarez‐Pez Jose M. 
Published: August 2011

AbstractA visible‐light‐excitable, ratiometric, brightly fluorescent pH indicator for measurements in the pH range 5–7 has been designed and synthesized by conjugatively linking the BODIPY fluorophore at the 3‐position to the pH‐sensitive ligand imidazole through an ethenyl bridge. The probe is available as cell membrane permeable methyl ester 8‐(4‐carbomethoxyphenyl)‐4,4‐difluoro‐3‐[2‐(1H‐imidazol‐4‐yl)ethenyl]‐1,5,7‐trimethyl‐3a,4a‐diaza‐4‐bora‐s‐indacene (I) and corresponding water‐soluble sodium carboxylate, sodium 8‐(4‐carboxylatophenyl)‐4,4‐difluoro‐3‐[2‐(1H‐imidazol‐4‐yl)ethenyl]‐1,5,7‐trimethyl‐3a,4a‐diaza‐4‐bora‐s‐indacene (II). The fluorescence quantum yield Φf of ester I is very high (0.8–1.0) in the organic solvents tested. The fluorescence lifetime (ca. 4 ns) of I in organic solvents with varying polarity/polarizability (from cyclohexane to acetonitrile) is independent of the solvent with a fluorescence rate constant kf of 2.4×108 s−1. Probe I is readily loaded in the cytosol of live cells, where its high fluorescence intensity remains nearly constant over an extended time period. Water‐soluble indicator II exhibits two acid–base equilibria in aqueous solution, characterized by pKa values of 6.0 and 12.6. The Φf value of II in aqueous solution is high: 0.6 for the cationic and anionic forms of the imidazole ligand, and 0.8 for neutral imidazole. On protonation–deprotonation in the near‐neutral pH range, UV/Vis absorption and fluorescence spectral shifts along with isosbestic and pseudo‐isoemissive points are observed. This dual‐excitation and dual‐emission pH indicator emits intense green‐yellow fluorescence at lower pH and intense orange fluorescence at higher pH. The influence of ionic strength and buffer concentration on the absorbance and steady‐state fluorescence of II has also been investigated. The apparent pKa of the near‐neutral acid–base equilibrium determined by spectrophotometric and fluorometric titration is nearly independent of the added buffer and salt concentration. In aqueous solution in the absence of buffer and in the pH range 5.20–7.45, dual exponential fluorescence decays are obtained with decay time τ1=4.3 ns for the cationic and τ2=3.3 ns for the neutral form of II. The excited‐state proton exchange of II at near‐neutral pH becomes reversible on addition of phosphate (H2PO4−/HPO42−) buffer, and a pH‐dependent change of the fluorescence decay times is induced. Global compartmental analysis of fluorescence decay traces collected as a function of pH and phosphate buffer concentration was used to recover values of the deactivation rate constants of the excited cationic (k01=2.4×108 s−1) and neutral (k02=3.0×108 s−1) forms of II.
Six IPR Isomers of C90 Fullerene Captured as Chlorides: Carbon Cage Connectivities and Chlorination Patterns
Authors: Troyanov Sergey I. , Yang Shangfeng , Chen Chuanbao , Kemnitz Erhard 
Published: August 2011

AbstractThree C90 fractions were isolated by multi‐step HPLC from fullerene soot obtained from direct current (DC) arc discharge of undoped graphite rods. C90 of each fraction was chlorinated with VCl4 or SbCl5 in ampoules at 290–310 °C, affording a series of C90Cln compounds. Single‐crystal X‐ray crystallography with the use of synchrotron radiation resulted in structure elucidation of seven C90Cln compounds containing six different isolated pentagon rule (IPR) C90 cages (the number of the C90 isomer is given in the parentheses): C90(46)Cl32 (I), C90(34)Cl32 (II), C90(35)Cl24 (III), and C90(35)Cl28 (IV), C90(32)Cl24 (V as co‐crystals with III), co‐crystals of C90(30)Cl22 and C90(28)Cl24 (VI), and C90(28)Cl24 (VII). Cage connectivities of C90 isomers 35 and 28 have been crystallographically confirmed for the first time. The chlorination patterns of the C90Cln molecules are discussed in terms of the formation of isolated aromatic systems and isolated CC double bonds on the fullerene cage. The distribution of six C90 isomers in three HPLC fractions is compared with data from the literature.
Hexaazatriphenylene (HAT) versus tri‐HAT: The Bigger the Better?
Authors: Juárez Rafael , Oliva María Moreno , Ramos Mar , Segura José L. , Alemán Carlos , Rodríguez‐Ropero Francisco , Curcó David , Montilla Francisco , Coropceanu Veaceslav , Brédas Jean Luc , Qi Yabing , Kahn Antoine , Ruiz Delgado M. Carmen , Casado Juan , López Navarrete Juan T. 
Published: August 2011

AbstractA new hexaazatriphenylene (HAT) derivative formed by the fusion of three HAT units has been prepared and its electronic and molecular structures have been fully characterized by optical and vibrational Raman spectroscopy, electrochemistry, solid‐state UV and inverse photoemission spectroscopy (UPS and IPES), and by quantum‐chemical calculations. A comparative HAT versus tri‐HAT study was performed. The fusion of three HAT molecules causes modifications in the optical and electrochemical properties consistent with enhanced π‐electron delocalization attained in a bigger planar core. Such combined experimental and theoretical studies are useful to balance chemical design with supramolecular engineering directed to find enhanced characteristics for new organic semiconductor applications.
CO2 Insertion into Metal–Carbon Bonds: A Computational Study of RhI Pincer Complexes
Authors: Ostapowicz Thomas G. , Hölscher Markus , Leitner Walter 
Published: August 2011

AbstractCatalytic carboxylation reactions that use CO2 as a C1 building block are still among the ‘dream reactions’ of molecular catalysis. To obtain a deeper insight into the factors that control the fundamental steps of potential catalytic cycles, we performed a detailed computational study of the insertion reaction of CO2 into rhodium–alkyl bonds. The minima and transition‐state geometries for 38 pincer‐type complexes were characterized and the according energies for the CC bond‐forming step were determined. The electronic properties of the Rhalkyl bond were found to be more important for the magnitude of the activation barrier than the interaction between rhodium and CO2. The charge of the alkyl‐chain carbon atom, as well as agostic and orbital interactions with the rhodium, exhibit the most pronounced influence on the energy of the transition states for the CO2 insertion reaction. By varying the backbone and the donor groups of the pincer ligand those properties can be tuned over a very broad range. Thus, it is possible to match the electronic and steric properties with the fundamental requirements of the CO2 insertion into rhodium–alkyl bonds of the ligand framework.
Nature of the Intermediates in Gold(I)‐Catalyzed Cyclizations of 1,5‐Enynes
Authors: López‐Carrillo Verónica , Huguet Núria , Mosquera Ángeles , Echavarren Antonio M. 
Published: August 2011

AbstractThe carbene or carbocationic nature of the intermediates in the gold‐catalyzed cycloisomerization of 1,5‐enynes can be revealed, depending on the ligands on the gold catalysts. Gold complexes with highly electron‐donating ligands promote reactions that proceed via intermediates with carbene‐like character, leading to products with a bicyclo[3.1.0]hexene skeleton. The intermediate cyclopropyl endo‐gold carbenes formed in this cyclization have been trapped, for the first time, to give biscyclopropane derivatives in a reaction that proceeds in a concerted fashion, according to DFT calculations.
Central‐to‐axial chirality transfer revealed by liquid crystals: A combined experimental and computational approach for the determination of absolute configuration of carboxylic acids with an α chirality centre
Authors: Ferrarini Alberta , Ferroni Fiammetta , Pieraccini Silvia , Rosini Carlo , Superchi Stefano , Spada Gian Piero 
Published: August 2011

AbstractThe conversion into 6,7‐dihydro‐5H‐dibenz[c,e]azepine (DAZ) N‐protected amides is a viable route for the determination of the absolute configuration of chiral 2‐substituted carboxylic acids. The biphenyl moiety of DAZ, besides being a probe of chirality for the electronic circular dichroism (ECD) spectroscopy, makes these systems suitable for configuration assignment by exploiting the chirality amplification which occurs in nematic liquid crystals. To assess the reliability of the liquid crystal method in detecting the absolute stereochemistry of chiral amides bound to a biphenyl group, we measured the helical twisting power of a series of DAZ‐N‐protected amides and compared these data with the results obtained from ECD measurements. We will show that the liquid crystal method, corroborated by HTP predictions, is trustworthy with our biphenyl derivatives, even when ECD spectra are ambiguous for the presence of aryl moieties displaying strong UV absorptions in the same range of the biphenyl chromophore. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Refined model of optical activity of cis‐dihydrodiol metabolites: Role of 1,3‐diene conformation in the electronic circular dichroism spectra
Authors: Kwit Marcin , Gawronski Jacek 
Published: August 2011

AbstractThe effect of the secondary structural feature, that is, nonplanarity of carbon–carbon double bonds, on the rotatory strength of the long‐wavelength π–π* electronic transition has been investigated for the series of monocyclic cis‐dihydrodiol arene metabolites and model compounds. The contribution from nonplanar CC bonds to the overall rotatory strength of the π–π* electronic transition is more significant than the contribution from twisted 1,3‐diene chromophore. The effect of the substitution pattern in the cyclohexadiene skeleton may be decisive for the sign of the long‐wavelength π–π* Cotton effect. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Experimental methods for measuring optical rotatory dispersion: Survey and outlook
Authors: Castiglioni Ettore , Abbate Sergio , Longhi Giovanna 
Published: August 2011

AbstractThe measurement of optical rotation (OR) and optical rotatory dispersion has been finding renewed interest for some years, because of advancement in computational methods and in the performance of new experiments. Here, we shortly review the traditional and most‐used experimental methods. We define and discuss the two main types of approaches in measuring OR: the intensity method and the optical null method. We report on some new results obtained by redesigning experiments based on the first approach, by adapting nonsophisticated hardware to current circular dichroism instrumentation. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Asymmetric addition of dimethylzinc to alkylidenmalonates mediated by phosphorous ligands: A new synthetic route to floral fragrances
Authors: Superchi Stefano , Marchitiello Valeria , Pisani Laura , Scafato Patrizia 
Published: August 2011

AbstractSix new phosphite ligands were prepared and their efficiency as chiral ligands was investigated in the copper‐catalyzed asymmetric conjugate addition of dimethylzinc to diethyl 3‐phenylpropylidenmalonate (5), affording the addition product with ees up to 74%. Moreover, a simple and straightforward route to floral fragrances Phenoxanol, Citralis, and Nitrile Citralis in optically active form through the above cited reaction was proposed. Chirality, 2011. © 2011 Wiley‐Liss, Inc.