bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of stereospecificity in the radical polymerization of N‐methyl‐N‐(2‐pyridyl)acrylamide by conformational switching of the monomer with protonation
Authors: Hirano Tomohiro , Morikami Akihiro , Ute Koichi 
Published: July 2011

AbstractRadical polymerization of N‐methyl‐N‐(2‐pyridyl)acrylamide (MPyAAm) was carried out in dichloromethane at low temperatures in the presence of trifluoroacetic acid (TFA). The m dyad contents of the polymers obtained at 0 °C increased linearly from 37 to 60% with an increase in the [TFA]0/[MPyAAm]0 ratio from 1 to 5. Nuclear magnetic resonance (NMR) analysis of MPyAAm–TFA mixtures in dichloromethane‐d2 revealed that the favorable conformation in terms of the pyridyl group to the carbonyl group in MPyAAm switched from s‐trans to s‐cis by protonation. The results suggest that controlling the conformation of MPyAAm resulted in control of the stereospecificity in radical polymerization of the monomer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of a novel macroinimer based on thiophene and poly(ε‐caprolactone) and its use in electrochromic device application
Authors: Kucuk Asuman Celik , Yilmaz Faruk , Can Hatice , Durmaz Hakan , Kosemen Arif , Muftuoglu Ali Ekrem 
Published: July 2011

AbstractSynthesis of a novel macroinimer comprising poly(ε‐caprolactone) (PCL) and thiophene (Th) and its use in electrochromic device (ECD) application have been reported. First, a novel Th monomer (5) with miktofuntional initiator groups (primary hydroxyl and tertiary bromide at the third position of the thiophene ring) was synthesized in a four‐step reaction sequence. Density functional theory‐predicted bond lengths, angles, and vibrations of 5 were in good agreement with available experimental vibrational spectra. Subsequently, ring‐opening polymerization of ε‐caprolactone (ε‐CL) was carried out in bulk using 5 as the initiator and tin(II) 2‐ethylhexanoate (Sn(Oct)2) as the catalyst at 115 °C, which led to α‐thiophene end‐capped PCL macroinimer (PCL‐Th). Furthermore, PCL‐Th macroinimer was used in electrochemical copolymerization with pyrrole (Py) and Th. PCL‐Th/PTh copolymer film synthesized on indium tin oxide‐coated glass slide showed electrochromic behavior. Optical analyses of the PCL‐Th/PTh copolymer film indicated that the copolymer film was suitable to be used as an anodically coloring material for ECD applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Nanostructured organic–inorganic hybrid films prepared by the sol–gel method from self‐assemblies of PS‐b‐paptes‐b‐PS triblock copolymers
Authors: Gamys CÉ Guinto , Beyou Emmanuel , Bourgeat‐Lami Elodie , Alcouffe Pierre , David Laurent 
Published: July 2011

AbstractABA‐based triblock copolymers of styrene as block ends and gelable 3‐acryloxypropyltriethoxysilane (APTES) as the middle block were successfully prepared through nitroxide‐mediated polymerization (NMP). The copolymers were bulk self‐assembled into films and the degree of phase separation between the two blocks was evaluated by differential scanning calorimetry (DSC). Their morphology was examined through small angle X‐ray scattering (SAXS) and transmission electron microscopy (TEM), whereas the mechanical properties of the corresponding cross‐linked self‐assembled nanostructures were characterized by dynamic mechanical analysis (DMA). Acidic treatment of the triblock copolymers favored the hydrolysis and condensation reactions of the APTES‐rich nanophase, and induced a mechanical reinforcement evidenced by the increase of storage modulus values and the shift of the glass transition temperature to higher temperatures due to confinement effects. In addition, the lamellar structure of the hybrid films was retained after the removal of the organic part by calcination. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of polybenzoxazine/clay nanocomposites by in situ thermal ring‐opening polymerization using intercalated monomer
Authors: Demir Kubra Dogan , Tasdelen Mehmet Atilla , Uyar Tamer , Kawaguchi Asei William , Sudo Atsushi , Endo Takeshi , Yagci Yusuf 
Published: July 2011

AbstractA new class of polybenzoxazine/montmorillonite (PBz/MMT) nanocomposites has been prepared by the in situ polymerization of the typical fluid benzoxazine monomer, 3‐pentyl‐5‐ol‐3,4‐dihydro‐1,3‐benzoxazine, with intercalated benzoxazine MMT clay. A pyridine‐substituted benzoxazine was first synthesized and quaternized by 11‐bromo‐1‐undecanol and then used for ion exchange reaction with sodium ions in MMT to obtain intercalated benzoxazine clay. Finally, this organomodified clay was dispersed in the fluid benzoxazine monomers at different loading degrees to conduct the in situ thermal ring‐opening polymerization. Polymerization through the interlayer galleries of the clay led to the PBz/MMT nanocomposite formation. The morphologies of the nanocomposites were investigated by both X‐ray diffraction and transmission electron microscopic techniques, which suggested the partially exfoliated/intercalated structures in the PBz matrix. Results of thermogravimetric analysis confirmed that the thermal stability and char yield of PBz nanocomposites increased with the increase of clay content. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of multiarmed poly(3‐hexyl thiophene) star polymer with microgel core by GRIM and ATRP methods
Authors: Kim Hyun‐Ji , Lee Yun Jae , Hwang Seung Sang , Choi Dong Hoon , Yang Hoichang , Baek Kyung‐Youl 
Published: July 2011

AbstractRegioregular poly(3‐hexyl thiophene) (rr‐P3HT)‐based star polymers were synthesized by a crosslinking reaction of the linear rr‐P3HT macroinitiator and ethylene glycol dimethacrylate (EGDMA) crosslinker through Ru‐based atom transfer radical polymerization (ATRP), where the rr‐P3HT macroinitiator was prepared by Grignard metathesis method (GRIM) followed by end functionalization of the ATRP initiator with chlorophenylacetate (CPA) to the rr‐P3HT. Relatively high molecular weight of the star polymers were obtained (Mp = 8,988,000 g/mol), which consisted of large numbers of the rr‐P3HT arm chains radiating from the EGDMA‐based microgel core. The yield of the star polymers were strongly affected by the added amount of the EGDMA crosslinker. The crystalline structure of the rr‐P3HT by intermolecular π‐π stacking interaction gradually decreased as the star polymer formed, which was confirmed by differential scanning calorimeter (DSC), atomic force microscopy (AFM), and electro‐optical analyses. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Electron paramagnetic resonance measurement of trapped radical concentrations in frontally polymerized and bulk‐polymerized multifunctional (meth)acrylates
Authors: Thoma Anna , Dahal Ashutosh , Regmi Aayush , Valencia Alecia , Viner Veronika , Cueto Rafael , Baker Blane , Bunton Patrick , Pojman John A. 
Published: July 2011

AbstractFor the first time, electron paramagnetic resonance spectroscopy was used to compare numbers and distributions of radicals produced in frontal free‐radical polymerization of multifunctional acrylates and methacrylates to those produced by bulk free‐radical polymerization. A comparison of radical concentrations was performed for individual polymers and selected copolymers of trimethylolpropane trimethacrylate (TMPTMA), 1,6‐hexanediol diacrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate (PETA). Frontally polymerized samples showed a large spike in intensity at the point of initiation. Within a few centimeters, the radical signal diminished to a steady state. The radical concentration remained almost constant over 3 months under helium in flame‐sealed tubes. The types of radicals were similar to those in bulk polymerization. For both TMPTMA and PETA, frontally polymerized samples had significantly higher numbers of radicals than did the bulk‐prepared samples, achieving concentrations as high as 8.7 × 10−3 mol/kg in the frontally prepared samples of TMPTMA. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
High modulus ratio shape‐memory polymers achieved by combining hydrogen bonding with controlled crosslinking
Authors: Pan Yi , Liu Tuo , Li Jing , Zheng Zhaohui , Ding Xiaobin , Peng Yuxing 
Published: July 2011

AbstractA new type of poly(methyl acrylate)‐co‐(acrylic acid) (PMA‐AA) networks obtained by combining hydrogen bonding with controlled crosslinking exhibit full and rapid shape‐memory recovery. The structure, thermal properties, dynamical mechanical properties and shape‐memory effects of these networks were presented. High modulus ratios were achieved for the series of PMA‐AA networks based on intense self‐complementary hydrogen bonding in poly(acrylic acid) (PAA) segments. This lead to excellent shape‐memory effects with strain‐recovery ratio above 99%. Meanwhile, faster recovery speed was achieved by the synergistic effect of hydrogen bonding and controlled crosslinking compared to the linear PMA‐AA copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1241–1245, 2011
Integrated waveguide sensor utilizing organic photodiodes
Authors: Lamprecht Bernhard , Kraker Elke , Sagmeister Martin , Köstler Stefan , Galler Nicole , Ditlbacher Harald , Ungerböck Birgit , Abel Tobias , Mayr Torsten 
Published: July 2011

AbstractWe present a novel optical sensor platform, combining monolithically integrated ring‐like sensor waveguides together with ring‐shaped thin‐film organic photodiodes (OPDs) on one substrate. The OPDs serve as integrated light detectors, simplifying the detection system by minimizing the number of required optical components. The waveguide structures, including a means of coupling light in and out of the waveguides, serve as sensing elements. The functionality of the concept is demonstrated by an integrated carbon dioxide sensor, utilizing absorbance as sensing principle. The integrated optical sensor platform is suitable for the parallel detection of multiple parameters in a single sensor chip using sensor arrays. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conditional symmetric instability in sting‐jet storms
Authors: Gray S. L. , Martínez‐Alvarado O. , Baker L. H. , Clark P. A. 
Published: July 2011

AbstractSting jets are transient mesoscale jets of air that descend from the tip of the cloud head towards the top of the boundary layer in severe extratropical cyclones and can lead to damaging surface wind gusts. This recently identified jet is distinct from the well‐documented jets associated with the cold and warm conveyor belts. One mechanism proposed for their development is the release of conditional symmetric instability (CSI). Here the spatial distribution and temporal evolution of several CSI diagnostics in four severe storms are analysed. A sting jet has been identified in three of these storms; for comparison, we also analysed one storm that did not have a sting jet, even though it had many of the apparent features of sting‐jet storms. The sting‐jet storms are distinct from the non‐sting‐jet storms by having much greater and more extensive conditional instability (CI) and CSI. CSI is released by ascending air parcels in the cloud head in two of the sting‐jet storms and by descending air parcels in the other sting‐jet storm. By contrast, only weak CI to ascending air parcels is present at the cloud‐head tip in the non‐sting‐jet storm. CSI released by descending air parcels, as diagnosed by decaying downdraught slantwise convective available potential energy (DSCAPE), is collocated with the sting jets in all three sting‐jet storms and has a localised maximum in two of them. Consistent evolutions of saturated moist potential vorticity are found. We conclude that CSI release has a role in the generation of the sting jet, that the sting jet may be driven by the release of instability to both ascending and descending parcels, and that DSCAPE could be used as a discriminating diagnostic for the sting jet based on these four case‐studies. Copyright © 2011 Royal Meteorological Society and British Crown Copyright, the Met Office
A maximum entropy approach to the problem of parametrization
Authors: Verkley W. T. M. 
Published: July 2011

AbstractIt is shown that the principle of maximum entropy, as formulated by Jaynes, can be applied to parametrize the effect of unresolved variables on resolved variables in a dynamical system proposed by Lorenz. The starting point is the assumption that the unresolved variables are in a state of statistical equilibrium on the time‐scale of the resolved variables. The probability density function that describes the statistics of the unresolved variables is then determined by requiring that its information entropy is maximal under the constraint that the average time rate of change of the unresolved variables' energy is zero. By using this probability density function to determine the average effect of the unresolved variables on the resolved variables, a linear damping of the resolved variables is found. After incorporating the linear damping in the equations of the resolved system, the principle of maximum entropy is applied a second time to shed light on the statistics of the resolved system. The consequences are studied of using a priori probability density functions that go beyond Laplace's principle of indifference. Copyright © 2011 Royal Meteorological Society
Semiparametric transformation models for joint analysis of multivariate recurrent and terminal events
Authors: Zhu Liang , Sun Jianguo , Srivastava Deo Kumar , Tong Xingwei , Leisenring Wendy , Zhang Hui , Robison Leslie L. 
Published: July 2011

AbstractRecurrent event data occur in many clinical and observational studies, and in these situations, there may exist a terminal event such as death that is related to the recurrent event of interest. In addition, sometimes more than one type of recurrent events may occur, that is, one may encounter multivariate recurrent event data with some dependent terminal event. For the analysis of such data, one must take into account the dependence among different types of recurrent events and that between the recurrent events and the terminal event. In this paper, we extend a method for univariate recurrent and terminal events and propose a joint modeling approach for regression analysis of the data and establish the finite and asymptotic properties of the resulting estimates of unknown parameters. The method is applied to a set of bivariate recurrent event data arising from a long‐term follow‐up study of childhood cancer survivors. Copyright © 2011 John Wiley & Sons, Ltd.
Assessing covariate imbalance in meta‐analysis studies
Authors: Aiello Fabio , Attanasio Massimo , Tinè Fabio 
Published: July 2011

The main goal of meta‐analysis is to combine data across studies or data sets to obtain summary estimates. In this paper, the novelty is to propose a statistical tool to assess a possible covariate imbalance in baseline variables to investigate similarity of trials. We conducted the detection of the covariate imbalance, first, through some graphical comparison of the empirical cumulative distribution functions or ECDFs, which are built by putting together arms or trials according to some risk factor, and second, through some non‐parametric tests such as the Kolmogorov–Smirnov and the Anderson–Darling tests. To overcome the huge presence of ties, we conducted the statistical tests on perturbed versions of the original data sets. The applications concern two real meta‐analyses of RCTs: the first one, on interferon‐alpha treatment of chronic hepatitis C, with 107 studies involved, and the second one, on cholesterol‐lowering treatment with statins, with 14 studies involved.The applications allow for analysis of both when risk factors reflecting demographic or clinical differences in experimental and control arms are balanced or not and when there are structural differences between the levels of some study variables, in order to proceed eventually with the pooling of the studies. We developed our suggestion, which is a quantitative way to assess combinability in meta‐analysis, only with respect to RCTs, but it could be applied to a minor extent to non‐RCTs. Copyright © 2011 John Wiley & Sons, Ltd.
Modeling continuous diagnostic test data using approximate Dirichlet process distributions
Authors: Ladouceur Martin , Rahme Elham , Bélisle Patrick , Scott Allison N. , Schwartzman Kevin , Joseph Lawrence 
Published: July 2011

AbstractThere is now a large literature on the analysis of diagnostic test data. In the absence of a gold standard test, latent class analysis is most often used to estimate the prevalence of the condition of interest and the properties of the diagnostic tests. When test results are measured on a continuous scale, both parametric and nonparametric models have been proposed. Parametric methods such as the commonly used bi‐normal model may not fit the data well; nonparametric methods developed to date have been relatively complex to apply in practice, and their properties have not been carefully evaluated in the diagnostic testing context. In this paper, we propose a simple yet flexible Bayesian nonparametric model which approximates a Dirichlet process for continuous data. We compare results from the nonparametric model with those from the bi‐normal model via simulations, investigating both how much is lost in using a nonparametric model when the bi‐normal model is correct and how much can be gained in using a nonparametric model when normality does not hold. We also carefully investigate the trade‐offs that occur between flexibility and identifiability of the model as different Dirichlet process prior distributions are used. Motivated by an application to tuberculosis clustering, we extend our nonparametric model to accommodate two additional dichotomous tests and proceed to analyze these data using both the continuous test alone as well as all three tests together. Copyright © 2011 John Wiley & Sons, Ltd.
A dependency‐aware ontology‐based approach for deploying service level agreement monitoring services in Cloud
Authors: Dastjerdi Amir Vahid , Tabatabaei Sayed Gholam Hassan , Buyya Rajkumar 
Published: July 2011

SUMMARYCloud computing offers virtualized computing elements on demand in a pay‐as‐you‐go manner. The major motivations to adopt Cloud services include no upfront investment on infrastructure and transferring responsibility of maintenance, backups, and license management to Cloud Providers. However, one of the key challenges that holds businesses from adopting Cloud computing services is that, by migrating to Cloud, they move some of their information and services out of their direct control. Their main concern is how well the Cloud providers keep their information (security) and deliver their services (performance). To cope with this challenge, several service level agreement management systems have been proposed. However, monitoring service deployment as a major responsibility of those systems have not been deeply investigated yet. Therefore, this paper shows how monitoring services have to be described, deployed (discovered and ranked), and then how they have to be executed to enforce accurate penalties by eliminating service level agreement failure cascading effects on violation detection. Copyright © 2011 John Wiley & Sons, Ltd.
Adaptive routing algorithm for network load balancing
Authors: Une Hiroyuki , Qian Fei , Hirata Hironori 
Published: July 2011

AbstractThis paper introduces a routing algorithm which distributes the network traffic for each feasible route based on the reinforcement learning scheme. The aim of this algorithm is to reduce the transfer delay caused by congestion of the network. Most routing algorithms based on the reinforcement learning scheme could not avoid forwarding traffic toward the source of data packets. This property creates transfer loops and a lot of packet loss. In particular, the transfer loop may cause change in the order of packets, and also retransmit on the TCP connection. Thus, we employ a method that estimates the lower boundary of the probability for valid route to the destination, and this lower boundary can be used to reject the routes which cause the transfer loop. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Relationship between intracellular Ca2+ and ROS during fluoride‐induced injury in SH‐SY5Y cells
Authors: Xu Zhixia , Xu Bayi , Xia Tao , He Weihong , Gao Ping , Guo Lijuan , Wang Zhenglun , Niu Qiang , Wang Aiguo 
Published: July 2011

AbstractThe mechanisms underlying the neurotoxicology of endemic fluorosis still remain obscure. To explore lactate dehydrogenase (LDH) leakage, intracellular Ca2+ concentration ([Ca2+]i) and reactive oxygen species (ROS) production induced by fluoride, human neuroblastoma (SH‐SY5Y) cells were incubated with sodium fluoride (NaF, 20, 40, 80 mg/L) for 24 h, with 40 mg/L NaF for 3, 6, 12, 18, 24 h, and N‐acetyl‐L‐cysteine (NAC), ethyleneglycol‐bis‐(β‐aminoethyl ether)‐N,N,N′,N′‐tetraacetic acid (EGTA), 1,2‐bis(O‐aminophenoxy)ethane‐N,N,N′,N′‐tetraacetic acid tetra(acetoxymethyl) ester (BAPTA‐AM) alone or combined with fluoride (40 mg/L) respectively for 12 h in vitro. The results showed that the LDH levels in the 40 and 80 mg/L fluoride‐treated groups were significantly higher than that of the control group (in the test level of 0.05, the difference were statistical significance). [Ca2+]i and ROS reached a peak at 3 h and 12 h respectively after exposure to 40 mg/L fluoride. Fluoride coincubated with NAC (antioxidant) dramatically decreased ROS and LDH levels compared with the fluoride only group (in the test level of 0.05, the difference were statistical significance). However, fluoride‐induced increase in [Ca2+]i was not affected by NAC. BAPTA‐AM (intracellular calcium chelator) markedly lowered fluoride‐induced increase of [Ca2+]i, ROS and LDH levels while EGTA (extracellular calcium chelator) have no effects on them. These results indicate that fluoride‐related Ca2+ release from the site of intracellular calcium storage causes the elevation of ROS contributing to the cytotoxicity in SH‐SY5Y cells. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2013.
Exposed versus buried wires for fixation of lateral humeral condyle fractures in children: A comparison of safety and efficacy
Authors: Chan Lester Wai Mon , Siow Hua Ming 
Published: July 2011

Introduction Displaced fractures of the lateral condyle of the humerus are usually treated with open reduction and fixation with smooth Kirschner wires. These may be passed through the skin and left exposed or buried subcutaneously. Exposed wires may be removed in the outpatient clinic, whereas buried wires require a formal procedure under anaesthesia. This advantage may be offset if there is a higher rate of complications with exposed wires. The aim of this study was to compare the safety and efficacy of exposed and buried wires. Study design Retrospective cohort. Methods and materials Children with lateral condyle fractures of the humerus who had undergone surgery were identified from our departmental database. Case records and X-rays of 75 patients were reviewed. Results Forty-two patients had buried wires and 33 had exposed wires. There were no serious complications in either group. In the exposed wires group, 1 patient had a superficial wound infection that was treated effectively with 1 week of oral antibiotics, while 2 patients had hypergranulation of pin tracts treated with topical silver nitrate. None of the patients showed loss of reduction, deep infection, or any other complications requiring additional procedures. Discussion/conclusions There was no statistically significant difference in the rate of complications between the buried and exposed groups. We conclude that open reduction and exposed wiring is a safe and effective option for lateral condyle fractures, and recommend a period of 4 weeks of K-wire fixation followed by 2 weeks of backslab immobilisation as adequate for union with minimal risk of infection.