bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bifunctional Nanoparticles Constructed Using One‐Pot Encapsulation of a Fluorescent Polymer and Magnetic (Fe3O4) Nanoparticles in a Silica Shell
Authors: Lee Chang‐Soo , Chang Hee Hyun , Bae Pan‐Kee , Jung Juyeon , Chung Bong Hyun 
Published: December 2012

AbstractIntegration of biocompatible silica with a fluorescent polymer (PDDF) and superparamagnetic iron oxide nanoparticles (Fe3O4) to form uniform core–shell nanostructures has the great potential to form particles for use in multimodal bioimaging applications. Core–shell nanoparticles (PDDF/Fe3O4@SiO2) exhibit fluorescent and magnetic properties that are favorable for their use in magnetic separation and guiding applications, as well as optical and magnetic resonance (MR) imaging capabilities. With the biological analysis in an in vitro intracellular permeation and cytotoxicity test, chemical conjugation of the surface using folic acid (FA) molecules can provide the nanoparticles with cell‐targeting properties, localizing the nanoparticles to folate receptors (FRs) on target KB cells that over‐express the FRs. magnified image
Chain Microstructure, Crystallization, and Morphology of Olefinic Blocky Copolymers
Authors: Tong Zai‐Zai , Huang Jie , Zhou Bing , Xu Jun‐Ting , Fan Zhi‐Qiang 
Published: December 2012

AbstractThe chain microstructure, crystallization, and morphology of three olefinic blocky copolymers (OBCs) are compared. The weight percentage of the hard block and the octene content in it are calculated from the 13C NMR spectra with a two‐site first‐order Markovian model. The lengths of the hard blocks are compared from the melting and crystallization behaviors. The remarkable difference between the crystallinity measured by DSC, and wide‐angle X‐ray diffraction (WAXD) indicates the presence of partially ordered phases. Small angle X‐ray scattering (SAXS) shows that the partially ordered phases in OBC‐A are mainly located at the interface between the crystalline and amorphous phases, but exist as separated microdomains in OBC‐B. As the hard block becomes shorter, there are also more, separated partially ordered phases in OBC‐C. Spherulites are observed in all OBCs by POM and the size of the spherulites decreases in the order: OBC‐A > OBC‐B > OBC‐C. TEM shows that spherulites are poorly developed in a thin film of OBC‐B.
Semi‐Random Two‐Acceptor Polymers: Elucidating Electronic Trends Through Multiple Acceptor Combinations
Authors: Burkhart Beate , Khlyabich Petr P. , Thompson Barry C. 
Published: December 2012

AbstractFour semi‐random poly(3‐hexylthiophene) (P3HT)‐based donor/acceptor copolymers each containing two different acceptor monomers with a total acceptor content of 15% and a constant 1:1 acceptor ratio are synthesized (P3HTT‐BTD‐DPP, P3HTT‐TP‐DPP, P3HTT‐TP‐TPD, and P3HTT‐BTD‐TPD). All four polymers have considerably broadened absorption spectra compared with P3HT and the shape of the absorption profile and the bandgap of the two‐acceptor copolymers can be predicted through a linear combination of absorption profiles of the respective one‐acceptor semi‐random copolymers. Important properties of P3HT, such as semicrystallinity, high hole mobility, and favorable mixing with [6,6]‐phenyl‐C61‐butyric acid methyl ester (PC61BM) in solar cells at low fullerene ratios are retained for all of the two‐acceptor copolymers. The highest occupied molecular orbital (HOMO) energies of two‐acceptor copolymers are, in almost all cases, higher than the lowest measured value for the corresponding “parent” one‐acceptor polymers and are in some cases higher than the values for both. The HOMO energies correlate in a generally linear fashion with the Voc measured in solar cells. Efficiencies of up to 3% emphasize the promise of this class of polymers.
Analytic regularity and nonlinear approximation of a class of parametric semilinear elliptic PDEs
Authors: Hansen Markus , Schwab Christoph 
Published: December 2012

AbstractWe investigate existence and regularity of a class of semilinear, parametric elliptic PDEs with affine dependence of the principal part of the differential operator on countably many parameters. We establish a priori estimates and analyticity of the parametric solutions. We establish summability results of coefficient sequences of polynomial chaos type expansions of the parametric solutions in terms of tensorized Taylor‐, Legendre‐ and Chebyshev polynomials on the infinite‐dimensional parameter domain. We deduce rates of convergence for N term truncated approximations of expansions of the parametric solution. We also deduce spatial regularity of the solution, and establish convergence rates of N‐term discretizations of the parametric solutions with respect to these polynomials in parameter space and with respect to a multilevel hierarchy of finite element spaces in the spatial domain of the PDE.
The genus of HNN‐extensions
Authors: de Bessa Vagner Rodrigues , Zalesskii Pavel 
Published: December 2012

AbstractWe find a bound on the genus of an HNN‐extension HNN(K, A, f) with a finite base group K. We also give sufficient conditions when the genus is 1, i.e. when HNN(K, A, f) is determined by its profinite completion up to isomorphism with respect to the family of all virtually free groups.
Organic Nonvolatile Resistive Switching Memory Based on Molecularly Entrapped Fullerene Derivative within a Diblock Copolymer Nanostructure
Authors: Jo Hanju , Ko Jieun , Lim Jung Ah , Chang Hye Jung , Kim Youn Sang 
Published: December 2012

AbstractOrganic nonvolatile resistive switching memory is developed via selective incorporation of fullerene derivatives, [6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM), into the nanostructure of self‐assembled poly(styrene‐b‐methyl methacrylate) (PS10‐b‐PMMA130) diblock copolymer. PS10‐b‐PMMA130 diblock copolymer provides a spatially ordered nanotemplate with a 10‐nm PS nanosphere domain surrounded by a PMMA matrix. Spin casting of the blend solution of PS10‐b‐PMMA130 and PCBM spontaneously forms smooth films without PCBM aggregation in which PCBM molecules are incorporated within a PS nanosphere domain of PS10‐b‐PMMA130 nanostructure by preferential intermixing propensity of PCBM and PS. Based on the well‐defined PS10‐b‐PMMA130/PCBM nanostructure, resistive random access memory (ReRAM) exhibits significantly improved bipolar‐switching behavior with stable and reproducible properties at low operating voltages (RESET at 1.3 V and SET at −1.5 V) under ambient conditions. Finally, flexible memory devices are achieved using a nanostructured PS10‐b‐PMMA130/PCBM composite in which no significant degradation of electrical properties is observed before and after bending.
Near‐Infrared Responsive Conjugated Polymers to 1.5 μm and Beyond: Synthesis and Electrochromic Switching Application
Authors: Tang Tao , Ding Guoqiang , Lin Tingting , Chi Hong , Liu Chen , Lu Xuehong , Wang FuKe , He Chaobin 
Published: December 2012

AbstractAzulene‐containing conjugated polymers with near‐infrared absorption up to 1.5 μm and beyond are achieved by treating with trifluoroacetic acid (TFA). Density functional theory calculations reveal that the near‐infrared absorption arises from a strong intramolecular charge transfer transition on the polymer backbone, and the near‐infrared absorption can be tuned by the degree of protonation. Furthermore, TFA treated polymers show a ten‐fold enhancement in electrochromic contrast and significantly improved switching stability, suggesting that these polymers are promising candidates for fabrication of the first generation organic near‐infrared devices.
Phylogenetic composition and distribution of picoeukaryotes in the hypoxic northwestern coast of the Gulf of Mexico
Authors: Rocke Emma , Jing Hongmei , Liu Hongbin 
Published: December 2012

AbstractCoastal marine hypoxic, or low‐oxygen, episodes are an increasing worldwide phenomenon, but its effect on the microbial community is virtually unknown by far. In this study, the community structure and phylogeny of picoeukaryotes in the Gulf of Mexico, which are exposed to severe hypoxia in these areas was explored through a clone library approach. Both oxic surface waters and suboxic bottom waters were collected in August 2010 from three representative stations on the inner Louisiana shelf near the Atchafalaya and Mississippi River plumes. The bottom waters of the two more western stations were much more hypoxic in comparison to those of the station closest to the Mississippi River plume, which were only moderately hypoxic. A phylogenetic analysis of a total 175 sequences, generated from six 18S rDNA clone libraries, demonstrated a clear dominance of parasitic dinoflagellates from Marine alveolate clades I and II in all hypoxic waters as well as in the surface layer at the more western station closest to the Atchafalaya River plume. Species diversity was significantly higher at the most hypoxic sites, and many novel species were present among the dinoflagellate and stramenopile clades. We concluded that hypoxia in the Gulf of Mexico causes a significant shift in picoeukaryote communities, and that hypoxia may cause a shift in microbial food webs from grazing to parasitism.
Single‐cell analysis of cell viability after a biocide treatment unveils an absence of positive correlation between two commonly used viability markers
Authors: Ducret Adrien , Dukan Sam 
Published: December 2012

AbstractDiscrimination among viable/active or dead/inactive cells in a microbial community is a vital question to address issues on ecological microbiology or microbiological quality control. It is commonly assumed that metabolically active cells (ChemchromeV6 [CV6] procedure) correspond to viable cells (direct viable count procedure [DVC]), although this assumption has never been demonstrated and is therefore a matter of debate. Indeed, simultaneous determination of cell viability and metabolic activity has never been performed on the same cells. Here, we developed a microfluidic device to investigate the viability and the metabolic activity of Escherichia coli cells at single‐cell level. Cells were immobilized in a flow chamber in which different solutions were sequentially injected according to different scenarios. By using time‐lapse microscopy combined with automated tracking procedures, we first successfully assessed the ability of cells to divide and their metabolic activity at single‐cell level. Applying these two procedures on the same cells after a hypochlorous acid (HOCl) treatment, we showed that the ability of cells to divide and their metabolic activity were anticorrelated. These results indicate that the relation between CV6 uptake and cell viability may be partially incorrect. Care must be taken in using the terms “CV6‐positive” and “viable” synonymously.
An Overview of ELECTRE Methods and their Recent Extensions
Authors: Figueira José Rui , Greco Salvatore , Roy Bernard , Słowiński Roman 
Published: December 2012

ABSTRACTWe present main characteristics of ELECTRE (ELimination Et Choix Traduisant la REalité ‐ ELimination and Choice Expressing the REality) family methods, designed for multiple criteria decision aiding. These methods use as a preference model an outranking relation on the set of actions—it is constructed in result of concordance and nondiscordance tests involving a specific input preference information. After a brief description of the constructivist conception in which the ELECTRE methods are inserted, we present the main features of these methods. We discuss such characteristic features as the possibility of taking into account positive and negative reasons in the modelling of preferences, without requiring commensurable performance scales; the use of discriminating thresholds for taking into account the imperfect knowledge of data; the absence of systematic compensation between ‘gains’ and ‘losses’. The main weaknesses are also presented. Then, some aspects related to new developments are outlined. These are related to some new methodological developments, new procedures, axiomatic analysis, software tools and several other aspects. This paper is an updated version of a chapter published by the authors under the title ‘Electre Methods: Main Features and Recent Developments’ in C. Zopounidis and P. Pardalos (Editors): Handbook of Multicriteria Analysis, Springer, Berlin 2010, pp. 51–89. Copyright © 2012 John Wiley & Sons, Ltd.
A Simulated Annealing Algorithm for Noisy Multiobjective Optimization
Authors: Mattila Ville , Virtanen Kai , Hämäläinen Raimo P. 
Published: December 2012

ABSTRACTThis paper presents a new simulated annealing (SA) algorithm for noisy multiobjective optimization with continuous decision variables. A novel feature of the algorithm in the context of SA is that the performance of a candidate solution is determined by estimating the probabilities that the candidate is dominated by the current non‐dominated solutions. The sum of these probabilities provides a scalar performance measure that is used to determine the acceptance of the candidate as the current solution and whether the candidate is inserted into the non‐dominated set. The second novel feature of the algorithm is the technique utilized for generating candidate solutions. Empirical probability distributions for sampling the new values of the decision variables are constructed on the basis of the values of the variables in the current non‐dominated set. Thus, the information contained by the non‐dominated set is utilized to improve the quality of the generated candidates, whereas this information is ignored in the existing multiobjective SA algorithms. The proposed algorithm is compared with a reference state‐of‐the‐art evolutionary algorithm as well as two other SA algorithms in numerical experiments involving 16 problems from commonly applied test suites. The proposed algorithm performs as good or better compared with the reference algorithms in majority of the experiments and therefore represents a promising solution method for noisy multiobjective optimization problems. Copyright © 2012 John Wiley & Sons, Ltd.
In vitro maturation of oocytes alters gene expression and signaling pathways in bovine cumulus cells
Authors: Salhab Mohamad , Dhorne‐Pollet Sophie , Auclair Sylvain , Guyader‐Joly Catherine , Brisard Daphné , Dalbies‐Tran Rozenn , Dupont Joelle , Ponsart Claire , Mermillod Pascal , Uzbekova Svetlana 
Published: December 2012

AbstractIn vitro maturation (IVM) of immature oocytes is widely used in assisted reproduction technologies in cattle, and is increasingly used to treat human infertility. The development competence of IVM oocytes, however, is lower than preovulatory, in vivo‐matured oocytes. During maturation, cumulus cells (CC) are metabolically coupled with an oocyte and support the acquisition of its developmental potential. Our objective was to identify genes and pathways that were affected by IVM in bovine CC. Microarray transcriptomic analysis of CC enclosing in vitro‐ or in vivo‐mature oocytes revealed 472 differentially expressed genes, including 28% related to apoptosis, correlating with twofold higher cell death after IVM than in vivo, as detected by TUNEL. Genes overexpressed after IVM were significantly enriched in functions involved in cell movement, focal adhesion, extracellular matrix function, and TGF‐beta signaling, whereas under‐expressed genes were enriched in regulating gene expression, energy metabolism, stress response, and MAP kinases pathway functions. Differential expression of 15 genes, including PAG11 (increased) and TXNIP (decreased), which were never detected in CC before, was validated by real‐time RT‐PCR. Moreover, protein quantification confirmed the lower abundance of glutathione S‐transferase A1 and prostaglandin G/H synthase 2, and the higher abundance of hyaluronan synthase 2 and SMAD4, a member of TGF‐beta pathway, in CC after IVM. Phosphorylation levels of SMAD2, MAPK3/1, and MAPK14, but not MAPK8, were higher after IVM that in vivo. In conclusion, IVM provokes the hyper‐activation of TGF‐beta and MAPK signaling components, modifies gene expression, leads to increased apoptosis in CC, and thus affects oocyte quality. Mol. Reprod. Dev. © 2012 Wiley Periodicals, Inc.
Improved first‐pass spiral myocardial perfusion imaging with variable density trajectories
Authors: Salerno Michael , Sica Christopher , Kramer Christopher M. , Meyer Craig H. 
Published: December 2012

PurposeTo develop and evaluate variable‐density spiral first‐pass perfusion pulse sequences for improved efficiency and off‐resonance performance and to demonstrate the utility of an apodizing density compensation function (DCF) to improve signal‐to‐noise ratio (SNR) and reduce dark‐rim artifact caused by cardiac motion and Gibbs Ringing.MethodsThree variable density spiral trajectories were designed, simulated, and evaluated in 18 normal subjects, and in eight patients with cardiac pathology on a 1.5T scanner.ResultsBy using a DCF, which intentionally apodizes the k‐space data, the sidelobe amplitude of the theoretical point spread function (PSF) is reduced by 68%, with only a 13% increase in the full‐width at half‐maximum of the main‐lobe when compared with the same data corrected with a conventional variable‐density DCF, and has an 8% higher resolution than a uniform density spiral with the same number of interleaves and readout duration. Furthermore, this strategy results in a greater than 60% increase in measured SNR when compared with the same variable‐density spiral data corrected with a conventional DCF (P < 0.01). Perfusion defects could be clearly visualized with minimal off‐resonance and dark‐rim artifacts.ConclusionVariable‐density spiral pulse sequences using an apodized DCF produce high‐quality first‐pass perfusion images with minimal dark‐rim and off‐resonance artifacts, high SNR and contrast‐to‐noise ratio, and good delineation of resting perfusion abnormalities. Magn Reson Med 70:1369–1379, 2013. © 2012 Wiley Periodicals, Inc.
Turbo fast three‐dimensional carotid artery black‐blood MRI by combining three‐dimensional MERGE sequence with compressed sensing
Authors: Li Bo , Dong Li , Chen Bin , Ji Shuangxi , Cai Wenchao , Wang Ye , Zhang Jue , Zhang Zhaoqi , Wang Xiaoying , Fang Jing 
Published: December 2012

PurposeIn this study, we sought to investigate the feasibility of turbo fast three‐dimensional (3D) black‐blood imaging by combining a 3D motion‐sensitizing driven equilibrium rapid gradient echo sequence with compressed sensing.MethodsA pseudo‐centric phase encoding order was developed for compressed sensing‐3D motion‐sensitizing driven equilibrium rapid gradient echo to suppress flow signal in undersampled 3D k‐space. Nine healthy volunteers were recruited for this study. Signal‐to‐tissue ratio, contrast‐to‐tissue ratio (CTR) and CTR efficiency (CTReff) between fully sampled and undersampled images were calculated and compared in seven subjects. Moreover, isotropic high resolution images using different compressed sensing acceleration factors were evaluated in two other subjects.ResultsWall‐lumen signal‐to‐tissue ratio or CTR were comparable between the undersampled and the fully sampled images, while significant improvement of CTReff was achieved in the undersampled images. At an isotropic high spatial resolution of 0.7 × 0.7 × 0.7 mm3, all undersampled images exhibited similar level of the flow suppression efficiency and the capability of delineating outer vessel wall boundary and lumen‐wall interface, when compared with the fully sampled images.ConclusionThe proposed turbo fast compressed sensing 3D black‐blood imaging technique improves scan efficiency without sacrificing flow suppression efficiency and vessel wall image quality. It could be a valuable tool for rapid 3D vessel wall imaging. Magn Reson Med 70:1347–1352, 2013. © 2012 Wiley Periodicals, Inc.
Arrhythmia insensitive rapid cardiac T1 mapping pulse sequence
Authors: Fitts Michelle , Breton Elodie , Kholmovski Eugene G. , Dosdall Derek J. , Vijayakumar Sathya , Hong Kyung P. , Ranjan Ravi , Marrouche Nassir F. , Axel Leon , Kim Daniel 
Published: December 2012

PurposeTo develop an arrhythmia‐insensitive rapid (AIR) cardiac T1 mapping pulse sequence for quantification of diffuse fibrosis.MethodsAn arrhythmia‐insensitive cardiac T1 mapping pulse sequence was developed based on saturation recovery T1 weighting, which is inherently insensitive to heart rate and rhythm, and two single‐shot balanced steady‐state free precession image acquisitions with centric k‐space ordering, where T1 calculation is inherently insensitive to T2 effects. Its performance against conventional cardiac T1 mapping based on inversion recovery (i.e., MOLLI) is compared. Phantom experiments (T1 ranging from 535 to 2123 ms) were performed with heart rate and rhythm simulated at 60 and 120 beats per minute (bpm) and arrhythmia using an external triggering device. Ten human subjects and 17 large animals were scanned precontrast and 5, 10, and 15 min after contrast agent administration.ResultsCompared with the reference T1 mapping, AIR yielded lower normalized root‐mean‐square error than MOLLI (8% vs. 3%, respectively, at 60 bpm, 28% vs. 3%, respectively, at 120 bpm, and 22% vs. 3%, respectively, at arrhythmia). In vivo studies showed that T1 measurements made by MOLLI and AIR were strongly correlated (r = 0.99) but in poor agreement (mean difference = 161.8 ms, upper and lower 95% limits of agreements = 347.5 ms and −24.0 ms).ConclusionOur AIR pulse sequence may be clinically useful for assessment of diffuse myocardial fibrosis in patients. Magn Reson Med 70:1274–1282, 2013. © 2012 Wiley Periodicals, Inc.
Perfusion quantification by model‐free arterial spin labeling using nonlinear stochastic regularization deconvolution
Authors: Ahlgren André , Wirestam Ronnie , Petersen Esben Thade , Ståhlberg Freddy , Knutsson Linda 
Published: December 2012

PurposeQuantification of cerebral blood flow can be accomplished by model‐free arterial spin labeling using the quantitative STAR labeling of arterial regions (QUASAR) sequence. The required deconvolution is normally based on block‐circulant singular value decomposition (cSVD)/oscillation SVD (oSVD), an algorithm associated with nonphysiological residue functions and potential effects of arterial dispersion. The aim of this work was to amend this by implementing nonlinear stochastic regularization (NSR) deconvolution, previously used to retrieve realistic residue functions in dynamic susceptibility contrast MRI.MethodsTo characterize the residue function in model‐free arterial spin labeling, and possibly to improve absolute cerebral blood flow quantification, NSR was applied to deconvolution of QUASAR data. For comparison, SVD‐based deconvolution was also employed. Residue function characteristics and cerebral blood flow values from 10 volunteers were obtained. Simulations were performed to support the in vivo results.ResultsNSR was able to resolve realistic residue functions in contrast to the SVD‐based methods. Mean cerebral blood flow estimates in gray matter were 36.6 ± 2.6, 28.6 ± 3.3, 40.9 ± 3.6, and 42.9 ± 3.9 mL/100 g/min for cSVD, oSVD, NSR, and NSR with correction for arterial dispersion, respectively. In simulations, the NSR‐based perfusion estimates showed better accuracy than the SVD‐based approaches.ConclusionPerfusion quantification by model‐free arterial spin labeling is evidently dependent on the selected deconvolution method, and NSR is a feasible alternative to SVD‐based methods. Magn Reson Med 70:1470–1480, 2013. © 2012 Wiley Periodicals, Inc.