bluuebunny/crossref_metadata_2025_split huggingface dataset:
Palladium‐Catalysed Dehydrogenative sp3 CH Bonds Functionalisation into Alkenes: A Direct Access to N‐Alkenylbenzenesulfonamides
Authors: Bheeter Charles B. , Jin Rongwei , Bera Jitendra K. , Dixneuf Pierre H. , Doucet Henri 
Published: January 2014

AbstractThe palladium‐catalysed dehydrogenation of sp3 carbon‐hydrogen bonds of N‐alkylbenzenesulfonamides allows a simple access to N‐alkenylbenzenesulfonamides. The reaction proceeds with easily accessible catalysts, with pivalate as a base, and allows a variety of substituents both on nitrogen and on the arene moiety.magnified image
Effect of Small Globular Protein on the Dynamical Behavior of Long‐Chain Polyelectrolyte in Dilute Regime
Authors: Trabelsi Saber , Aschi Adel , Othman Tahar , Gharbi Abdelhafidh 
Published: January 2014

ABSTRACTThe dynamics of long‐chain polyelectrolyte complexed with a globular protein is investigated basing on dynamic light scattering in three phases respecting the pH of medium. In diluted regime, the data are analyzed in the context of multicomponent light scattering theory to treat the pairwise interaction. The adjustment of experimental results with theoretical prediction shows explicit expressions of the interaction parameter and diffusion coefficient of complex particle. The second virial coefficient A2, 12 is evaluated and discussed. By dynamic light scattering technique, we suggest an approximation of the number of protein molecules bound per polyelectrolyte chain in each phase. The aggregation process is less prone in the higher ratio, and the patches binding are more favored.
Formulation of a Self‐Assembling Polymeric Network System for Enhanced Oil Recovery Applications
Authors: Wei Bing , Romero‐Zerón Laura , Rodrigue Denis 
Published: January 2014

ABSTRACTThe chemical formulation and rheological properties of a novel self‐assembling polymer (SAP) network system were investigated for potential application in enhanced oil recovery (EOR). The inclusion complexes formed by surfactant (S) and β‐cyclodextrin (β‐CD) can associate with hydrolyzed polyacrylamides (HPAM) in aqueous solution, and subsequently establish the SAP network, which exhibits advanced viscoelasticity at the optimum molar ratio (S:β‐CD = 2:1). Furthermore, this system presents enhanced surface activity and superior mechanical and thermal stability, as well as tolerance to elevated brine salinity and hardness due to the network “interlocking effect”. Sandpack flood tests suggest the excellent mobility control ability of this system during polymer flooding, and also a moderate permeability reduction capacity, which makes it more cost effective in oil fields than the currently used HPAM. Regarding EOR performance, this polymeric system (SAP) produced approximately 19% more incremental oil than the baseline HPAM under the same experimental conditions.
Female red colobus monkeys maintain their densities through flexible feeding strategies in logged forests in Kibale National Park, Uganda
Authors: Milich Krista M. , Stumpf Rebecca M. , Chambers Josephine M. , Chapman Colin A. 
Published: January 2014

ABSTRACTBehavioral flexibility allows primates to cope with environmental variability. Quantifying primate responses to human habitat modifications allows an effective means of assessing coping mechanisms. Within Kibale National Park, Uganda, logging led to reduced primate food availability that still exists almost 50 years after the harvest. Following the predictions of the ideal free distribution theory, primate densities are expected to decrease in areas of lower resource availability so that the resources available per individual are equivalent in logged and old‐growth areas. However, counter to what would be predicted by the ideal free distribution theory, red colobus monkeys (Procolobus rufomitratus) occur at similar densities in logged and old‐growth areas of Kibale. This suggests that either the ecological differences between the two areas are not sufficient to impact red colobus densities or that animals in logged areas are compensating to changes in resource availability by using different foraging strategies. To test between these hypotheses, we examined four groups of red colobus, two in logged and two in old‐growth forests, and compared feeding behavior, feeding tree size, and tree productivity. Females in logged areas fed on resources from a greater number of plant species, fed on fewer resources from each species, and spent more time feeding than those in old‐growth areas. By expanding their diet, females in logged areas effectively increased the resources available to them, which may contribute to their ability to maintain similar densities to females in old‐growth areas. These findings have implications for an evolutionary understanding of how species deal with environmental change and considerations for conservation practices that determine what areas should be prioritized for protection. Am J Phys Anthropol 154:52–60, 2014. © 2014 Wiley Periodicals, Inc.
An Atypical Naturally Split Intein Engineered for Highly Efficient Protein Labeling
Authors: Thiel Ilka V. , Volkmann Gerrit , Pietrokovski Shmuel , Mootz Henning D. 
Published: January 2014

AbstractProtein trans‐splicing catalyzed by split inteins is a powerful technique for assembling a polypeptide backbone from two separate parts. However, split inteins with robust efficiencies and short fragments suitable for peptide synthesis are rare and have mostly been artificially created. The novel split intein AceL‐TerL was identified from metagenomic data and characterized. It represents the first naturally occurring, atypically split intein. The N‐terminal fragment of only 25 amino acids is the shortest natural intein fragment to date and was easily amenable to chemical synthesis with a fluorescent label. Optimal protein trans‐splicing activity was observed at low temperatures. Further improved mutants were selected by directed protein evolution. The engineered intein variants with up to 50‐fold increased rates showed unprecedented efficiency in chemically labeling of a diverse set of proteins. These inteins should prove valuable tools for protein semi‐synthesis and other intein‐related biotechnological applications.
Inorganic‐Base‐Mediated Hydroamination of Alkenyl Oximes for the Synthesis of Cyclic Nitrones
Authors: Peng Xingao , Tong Benny Meng Kiat , Hirao Hajime , Chiba Shunsuke 
Published: January 2014

AbstractA method based on hydroamination mediated by inorganic base was developed for the synthesis of cyclic nitrones from alkenyl oximes. DFT calculations of the reaction pathway suggested that this hydroamination could proceed through an unprecedented nucleophilic amination of the unactivated alkene by the oxime nitrogen atom. The transition state of this reaction is stabilized by an ionic interaction between a metal cation such as K+ and the oxime oxygen and negatively charged alkene moiety.
Octafunctionalized Biphenylenes: Molecular Precursors for Isomeric Graphene Nanostructures
Authors: Schlütter Florian , Nishiuchi Tomohiko , Enkelmann Volker , Müllen Klaus 
Published: January 2014

AbstractA straightforward method for the octafunctionalization of biphenylene based on the [2+2]‐cycloaddition of an aryne intermediate has been developed. This enabled a “North–South” extension of biphenylene towards isomeric graphene nanoribbons composed of four‐, six‐, and eight‐membered rings. This procedure furthermore allowed an “East–West” expansion to [n]phenylenes with different lengths. For the fabrication of isomeric nanongraphenes, octaarylbiphenylenes decorated with phenyl, pyrenyl, and thieno substituents were prepared. The subsequent oxidative cyclodehydrogenation provided an expanded helicene as a model compound.
Strukturaufklärung und Totalsynthese von Kulkenon
Authors: Symkenberg Gerrit , Kalesse Markus 
Published: January 2014

AbstractDie beeindruckenden biologischen Aktivitäten von Sekundärmetaboliten, die von Myxobakterien der Stämme von Sorangium cellulosum isoliert wurden, haben uns veranlasst, das ebenfalls aus Sorangium cellulosum isolierte Kulkenon zu synthetisieren. In unserer Synthese waren die von uns entwickelte syn‐selektive vinyloge Kobayashi‐Aldolreaktion und eine Ringschluss‐Heck‐Kupplung die entscheidenden Transformationen. Allerdings mussten wir nach der Synthese beim Vergleich der Spektren von authentischer und synthetischer Probe feststellen, dass es sich nicht um identische Verbindungen handelte. Mithilfe einer Kombination aus computergestützten Modellierungen und NOE‐Experimenten gelang es uns schließlich, einen überarbeiteten Strukturvorschlag für Kulkenon zu machen und mit einer erneuten Synthese zu bestätigen.
Anisotropic Gold Nanoparticles: Synthesis, Properties, Applications, and Toxicity
Authors: Li Na , Zhao Pengxiang , Astruc Didier 
Published: January 2014

AbstractAnisotropic gold nanoparticles (AuNPs) have attracted the interest of scientists for over a century, but research in this field has considerably accelerated since 2000 with the synthesis of numerous 1D, 2D, and 3D shapes as well as hollow AuNP structures. The anisotropy of these nonspherical, hollow, and nanoshell AuNP structures is the source of the plasmon absorption in the visible region as well as in the near‐infrared (NIR) region. This NIR absorption is especially sensitive to the AuNP shape and medium and can be shifted towards the part of the NIR region in which living tissue shows minimum absorption. This has led to crucial applications in medical diagnostics and therapy (“theranostics”), especially with Au nanoshells, nanorods, hollow nanospheres, and nanocubes. In addition, Au nanowires (AuNWs) can be synthesized with longitudinal dimensions of several tens of micrometers and can serve as plasmon waveguides for sophisticated optical devices. The application of anisotropic AuNPs has rapidly spread to optical, biomedical, and catalytic areas. In this Review, a brief historical survey is given, followed by a summary of the synthetic modes, variety of shapes, applications, and toxicity issues of this fast‐growing class of nanomaterials.
Zinc‐Catalyzed Borylation of Primary, Secondary and Tertiary Alkyl Halides with Alkoxy Diboron Reagents at Room Temperature
Authors: Bose Shubhankar Kumar , Fucke Katharina , Liu Lei , Steel Patrick G. , Marder Todd B. 
Published: January 2014

AbstractA new catalytic system based on a ZnII NHC precursor has been developed for the cross‐coupling reaction of alkyl halides with diboron reagents, which represents a novel use of a Group XII catalyst for CX borylation. This approach gives borylations of unactivated primary, secondary, and tertiary alkyl halides at room temperature to furnish alkyl boronates, with good functional‐group compatibility, under mild conditions. Preliminary mechanistic investigations demonstrated that this borylation reaction seems to involve one‐electron processes.
Preparation of a polyimide nanofiltration membrane for lubricant solvent recovery
Authors: Yuan Bingbing , Cao Min , Sun Haixiang , Wang Tao , Bu Xiaoxiao , Shi Deqing , Kong Ying , Li Peng 
Published: January 2014

ABSTRACTPolyimide (PI) membrane has been proven to be an efficient approach for solvent recovery. However, the inherent fragility of the PI membrane limits the range of separation conditions and process economics. In this study, copolyimides were synthesized from 3,3′,4,4′‐benzophenone–tetracarboxylic dianhydride (BTDA) and 4,4′‐biamino‐3,3′‐dimethyldiphenyl–methane (DMMDA) by chemical imidization in a two‐step procedure. Then, a PI nanofiltration (NF) membrane was prepared through a phase‐inversion process for solvent recovery from lube oil filtrates. The results indicated that the immersion of the PI (BTDA–DMMDA) NF membrane in a 1,6‐diaminohexane/ethanol crosslinking agent solution carried on the chemical crosslinking modification, which could effectively improve the solvent resistance of the NF membrane. Moreover, the addition of inorganic salt in the polymer solution further enhanced the solvent resistance and pressure resistance of the membrane, which was favorable for the solvent recovery. The lubricant rejection was above 93%, and the solvent flux was about 30 L m−2 h−1 with the NF membrane prepared in optimum conditions, and this membrane showed great potential for future development in the application of solvent recovery from lube oil filtrates. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40338.
Functionalized multi‐wall carbon nanotubes/silicone rubber composite as capacitive humidity sensor
Authors: Wang Dayue , Huang Ying , Cai Wenting , Tian Min , Liu Ping , Zhang Yugang 
Published: January 2014

ABSTRACTFunctionalized multi‐wall carbon nanotubes (MWCNTs) treated by mixed acids have been used to develop a capacitive humidity sensor based on MWCNTs/silicone rubber (SR) composite film. The MWCNTs/SR composites were prepared through conventional solution processed method. The micrographs of MWCNTs/SR composites were observed by transmission electron microscopy (TEM) and scanning electron microscope. The FT‐IR spectra demonstrated the successfully grafting of OH groups on the treated MWCNTs. The sensing properties of the composite at different relative humidity (RH) and frequency were characterized and linear sensing responses of the MWCNTs/SR composites to RH were observed. The treated MWCNTs/SR composite film (Tr‐film) had higher sensitivity than that of the untreated MWCNTs/SR composite film (Un‐film). Experimental data indicate that the Tr‐film exhibits an excellent long‐term stability, small hysteresis, and fine reproducibility. The response and recovery time of the Tr‐film were 30 and 27 s, respectively. Thereby, such Tr‐film had potential applications as humidity sensors. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40342.
Indicators for evaluation of progress in thermal stabilization reactions of polyacrylonitrile fibers
Authors: Arbab Shahram , Mirbaha Hamideh , Zeinolebadi Ahmad , Nourpanah Parviz 
Published: January 2014

ABSTRACTUsing different indices calculated from Fourier Transform Infrared Spectroscopy (FTIR), X‐ray Diffraction (XRD), and Differential Scanning Calorimetry (DSC) spectra, progress in stabilization reactions of three different commercial grade polyacrylonitrile (PAN) fibers is calculated. From each analysis technique quantitative indices are computed which could assess in some particular reactions. Combination of these indices gives further information about the progress of stabilization reactions which cannot be concluded from single indices. The results show that different indices are not fully consistent with each other, depending on the analysis technique and the changes they assess. The advantages and disadvantages of each index are investigated and practical indices are identified which can be used to design the optimum stabilization process. In addition, by combination of some indices it is possible to separate the temperature ranges in which reactions occur in amorphous or crystalline regions. This approach can be used to design appropriate stretching process during stabilization. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40343.
A highly selective electrochemical sensor for l‐tryptophan based on a screen‐printed carbon electrode modified with poly‐p‐phenylenediamine and CdS quantum dots
Authors: Boonchiangma Suthasinee , Srijaranai Supalax , Tuntulani Thawatchai , Ngeontae Wittaya 
Published: January 2014

ABSTRACTA new highly selective electrochemical sensor for the determination of l‐tryptophan was proposed by modifying the surface of screen‐printed carbon electrodes (SPCEs). The surface of SPCE was firstly modified by electropolymerization of p‐phenylenediamine (PPD). The polymer film was then covalently linked with cysteamine capped cadmium sulfide quantum dots (Cys‐CdS QDs) by using glutaraldehyde (GA) as a cross‐linker resulted in an organic–inorganic hybrid composite film (QDs/GA/PPD/SPCE). The modified electrode was applied as a working electrode for detecting various amino acids. It was found that the modified electrode gave an electrochemical response selectively to l‐tryptophan over other amino acids. The experimental parameters, including pH of solution, buffer types, electropolymerization cycles, scan rate, and accumulation time, were studied and optimized. The proposed sensor can be used to detect l‐tryptophan with a low detection limit of 14.74 µmol L−1 with good precision and the relative standard deviation less than 3.7%. The modified electrode was used to detect l‐tryptophan in beverage samples and gave satisfactory recoveries from 91.9 to 104.9%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40356.
Ecology, management, and conservation implications of North American beaver(Castor canadensis)in dryland streams
Authors: Gibson Polly P. , Olden Julian D. 
Published: January 2014

ABSTRACTAfter near‐extirpation in the early 20th century, beaver populations are increasing throughout many parts of North America. Simultaneously, there is an emerging interest in employing beaver activity for stream restoration in arid and semi‐arid environments (collectively, ‘drylands’), where streams and adjacent riparian ecosystems are expected to face heightened challenges from climate change and human population growth.Despite growing interest in reintroduction programmes, surprisingly little is known about the ecology of beaver in dryland streams, and science to guide management decisions is often fragmented and incomplete.This paper reviews the literature addressing the ecological effects and management of beaver activity in drylands of North America, highlighting conservation implications, distinctions between temperate and dryland streams, and knowledge gaps.Well‐documented effects of beaver activity in drylands include changes to channel morphology and groundwater processes, creation of perennial wetland habitat, and substantial impacts to riparian vegetation. However, many hypothesized effects derived from temperate streams lack empirical evidence from dryland streams.Topics urgently in need of further study include the distribution and local density of beaver dams; consequences of beaver dams for hydrology and water budgets; and effects of beaver activity on the spread of aquatic and riparian non‐native species.In summary, this review suggests that beaver activity can create substantial benefits and costs for conservation. Where active beaver introductions or removals are proposed, managers and conservation organizations are urged to implement monitoring programmes and consider the full range of possible ecological effects and trade‐offs.Copyright © 2014 John Wiley & Sons, Ltd.
Output Regulation for a Class of Infinite Dimensional Systems with an Unknown Exosystem
Authors: Wang Xinghu , Ji Haibo , Wang Chuanrui 
Published: January 2014

AbstractThis paper is about solving the output regulation problem for a class of infinite dimensional systems with an unknown exosystem. First, under the unit relative degree assumption, the infinite dimensional system is decomposed into a cascaded one composed of a one‐dimensional system and an infinite dimensional system. Then, the problem is solved by combining an adaptive internal model and an adaptive control. The presented results are illustrated via a periodic tracking problem of a heat equation.
Quality of life and other patient-reported outcomes following exenteration for pelvic malignancy
Authors: Young J M , Badgery-Parker T , Masya L M , King M , Koh C , Lynch A C , Heriot A G , Solomon M J 
Published: January 2014

AbstractBackgroundPelvic exenteration is highly radical surgery offering the only potential cure for locally advanced pelvic cancer. This study compared quality of life and other relevant patient-reported outcomes over 12 months for patients who did and those who did not undergo pelvic exenteration.MethodsConsecutive patients referred for consideration of pelvic exenteration completed clinical and patient-reported outcome assessments at baseline, hospital discharge (exenteration patients only), and 1, 3, 6, 9 and 12 months. Outcomes included cancer-specific quality of life (Functional Assessment of Cancer Therapy – Colorectal; FACT-C), physical and mental health status (Short Form 36 version 2), psychological distress (Distress Thermometer), and pain (study-specific composite) scores. Linear mixed modelling compared trajectories between exenteration and no-exenteration groups.ResultsAmong 182 patients, 148 (81.3 per cent) proceeded to exenteration. There were no baseline differences between the two groups. Among patients who had exenteration, the mean FACT-C score at baseline of 93.0 had reduced by 14·4 points at hospital discharge, but increased to 86·7 at 1 month after surgery and continued to improve, returning to baseline by 9 months. For patients in the no-exenteration group, FACT-C scores decreased between baseline and 1 month, increased slowly to 6 months and then began to decline at 9 months. There were few statistically or clinically significant differences in any patient-reported outcomes between the groups.ConclusionQuality of life and related patient-reported outcomes improve rapidly after pelvic exenteration surgery. For 9 months after surgery, these outcomes are comparable with those of similar do patients who do not have surgery; thereafter, there is a decline in patients who do not have exenteration. Pelvic exenteration can be performed with acceptable quality of life and patient-reported outcomes.
A chemometrics toolbox based on projections and latent variables
Authors: Eriksson Lennart , Trygg Johan , Wold Svante 
Published: January 2014

A personal view is given about the gradual development of projection methods—also called bilinear, latent variable, and more—and their use in chemometrics. We start with the principal components analysis (PCA) being the basis for more elaborate methods for more complex problems such as soft independent modeling of class analogy, partial least squares (PLS), hierarchical PCA and PLS, PLS‐discriminant analysis, Orthogonal projection to latent structures (OPLS), OPLS‐discriminant analysis and more.From its start around 1970, this development was strongly influenced by Bruce Kowalski and his group in Seattle, and his realization that the multidimensional data profiles emerging from spectrometers, chromatographs, and other electronic instruments, contained interesting information that was not recognized by the current one variable at a time approaches to chemical data analysis.This led to the adoption of what in statistics is called the data analytical approach, often called also the data driven approach, soft modeling, and more. This approach combined with PCA and later PLS, turned out to work very well in the analysis of chemical data. This because of the close correspondence between, on the one hand, the matrix decomposition at the heart of PCA and PLS and, on the other hand, the analogy concept on which so much of chemical theory and experimentation are based. This extends to numerical and conceptual stability and good approximation properties of these models.The development is informally summarized and described and illustrated by a few examples and anecdotes. Copyright © 2014 John Wiley & Sons, Ltd.