bluuebunny/crossref_metadata_2025 huggingface dataset:
Circular Dichroism and Linear Dichroism
Authors: Rodger Alison
Published: January 2014

Circular dichroism (CD) is the difference in absorption, A, of left and right circularly polarized light, Equation (1):

For randomly oriented systems such as solutions of molecules, only chiral molecules will show any CD intensity corresponding to their absorption bands. Chiral molecules are those molecules that cannot be superposed on their mirror images. Chiral is derived from the Greek word χϵιρ meaning hand, hence the alternate term for chirality, ‘handedness’. Two molecules that are mirror images of each other are often referred to asenantiomers, and equimolar mixtures of two enatiomers form a racemic mixture, which has no net CD intensity in solution. CD can be used to analyze chiral structures such as protein secondary structure in molecules and to probe interactions between chiral molecules and other molecules.

Linear dichroism (LD) is the difference in absorption of light linearly polarized parallel and perpendicular to an orientation axis, Equation (2):

LD can be used to provide orientation information about subunits of a molecular system such as small molecules absorbed onto stretched films, flow‐oriented DNAs and fibrous proteins, and lipid bilayer systems.
Photothermal Killing of Cancer Cells by the Controlled Plasmonic Coupling of Silica‐Coated Au/Fe2O3 Nanoaggregates
Authors: Sotiriou Georgios A. , Starsich Fabian , Dasargyri Athanasia , Wurnig Moritz C. , Krumeich Frank , Boss Andreas , Leroux Jean‐Christophe , Pratsinis Sotiris E.
Published: January 2014

Tumor ablation by thermal energy via the irradiation of plasmonic nanoparticles is a relatively new oncology treatment. Hybrid plasmonic‐superparamagnetic nanoaggregates (50–100 nm in diameter) consisting of SiO2‐coated Fe2O3 and Au (≈30 nm) nanoparticles were fabricated using scalable flame aerosol technology. By finely tuning the Au interparticle distance using the SiO2 film thickness (or content), the plasmonic coupling of Au nanoparticles can be finely controlled bringing their optical absorption to the near‐IR that is most important for human tissue transmittance. The SiO2 shell facilitates also dispersion and prevents the reshaping or coalescence of Au particles during laser irradiation, thereby allowing their use in multiple treatments. These nanoaggregates have magnetic resonance imaging (MRI) capability as shown by measuring their r2 relaxivity while their effectiveness as photothermal agents is demonstrated by killing human breast cancer cells with a short, four minute near‐IR laser irradiation (785 nm) at low flux (4.9 W cm‐2).
Hydrosilylation of Internal Alkynes Catalyzed by Tris‐ Imidazolium Salt‐Stabilized Palladium Nanoparticles
Authors: Planellas Marc , Guo Wusheng , Alonso Francisco , Yus Miguel , Shafir Alexandr , Pleixats Roser , Parella Teodor
Published: January 2014

Palladium nanoparticles stabilized with tris‐imidazolium tetrafluoroborates catalyze the stereoselective hydrosilylation of internal alkynes in a dry inert atmosphere to give (E)‐vinylsilanes in excellent yields. In the presence of controlled amounts of water a transfer hydrogenation reaction takes place with the formation of (Z)‐alkenes or the corresponding alkanes.

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Dissecting Anion Effects in Gold(I)‐Catalyzed Intermolecular Cycloadditions
Authors: Homs Anna , Obradors Carla , Lebœuf David , Echavarren Antonio M.
Published: January 2014

From a series of gold complexes of the type [t‐BuXPhosAu(MeCN)]X (X=anion), the best results in intermolecular gold(I)‐catalyzed reactions are obtained with the complex with the bulky and soft anion BAr4F− [BAr4F−=3,5‐bis(trifluoromethyl)phenylborate] improving the original protocols by 10–30% yield. A kinetic study on the [2+2] cycloaddition reaction of alkynes with alkenes is consistent with an scenario in which the rate‐determining step is the ligand exchange to generate the (η2‐phenylacetylene)gold(I) complex. We have studied in detail the subtle differences that can be attributed to the anion in this formation, which result in a substantial decrease in the formation of unproductive σ,π‐(alkyne)digold(I) complexes by destabilizing the conjugated acid formed.

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The N‐Alkylation of Sulfonamides with Alcohols in Water Catalyzed by the Water‐Soluble Iridium Complex {Cp*Ir[6,6′‐(OH)2bpy](H2O)}[OTf]2
Authors: Qu Panpan , Sun Chunlou , Ma Juan , Li Feng
Published: January 2014

The water‐soluble iridium complex {Cp*Ir[6,6′‐(OH)2bpy](H2O)}[OTf]2 (Cp*=η5‐pentamethylcyclopentadienyl, bpy=2,2′‐bipyridine) was found to be a general and highly efficient catalyst for the N‐alkylation of the poor nucleophilic sulfonamides with alcohols as alkylating agents in water. The presence of OH units in the bpy ligand is crucially important for the catalytic activity of the iridium complex. Mechanistic investigations revealed that the catalytically active species is a ligand‐metal bifunctional iridium complex bearing an N,N′‐chelated 2,2′‐bipyridinated ligand and an aqua ligand. Notably, the present catalytic system and the proposed mechanism provide a new horizon and scope for the development of “hydrogen autotransfer (or hydrogen‐borrowing) processes”.

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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

The 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.

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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

The 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

The 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

Behavioral 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

Protein 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

A 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

A 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

Die 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

Anisotropic 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

A 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

Polyimide (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

Functionalized 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

Using 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

A 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

After 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

This 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.
Overview of object oriented data analysis
Authors: Marron J. Steve , Alonso Andrés M.
Published: January 2014

Object oriented data analysis is the statistical analysis of populations of complex objects. In the special case of functional data analysis, these data objects are curves, where a variety of Euclidean approaches, such as principal components analysis, have been very successful. Challenges in modern medical image analysis motivate the statistical analysis of populations of more complex data objects that are elements of mildly non‐Euclidean spaces, such as lie groups and symmetric spaces, or of strongly non‐Euclidean spaces, such as spaces of tree‐structured data objects. These new contexts for object oriented data analysis create several potentially large new interfaces between mathematics and statistics. The notion of object oriented data analysis also impacts data analysis, through providing a framework for discussion of the many choices needed in many modern complex data analyses, especially in interdisciplinary contexts.
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

Background

Pelvic 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.

Methods

Consecutive 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.

Results

Among 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.

Conclusion

Quality 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.
Breakdown potential modelling of austenitic stainless steel
Authors: Jiménez‐Come Maria Jesus , Turias Ignacio J. , Ruiz‐Aguilar Juan Jesus , Trujillo Francisco J.
Published: January 2014

The breakdown potential is a crucial factor in the study of pitting corrosion resistance of stainless steel. This work aims to demonstrate the advantage of different chemometric techniques to estimate the breakdown potential of austenitic stainless steel. In order to predict pitting corrosion behaviour of stainless steel, a total of 60 samples of this alloy were subjected to electrochemical tests varying chloride ion concentration, pH and temperature. The experimental values of the breakdown potential, in addition to the tested environmental factors, were used to construct the predictive models based on support vector machines and artificial neural networks. A multiple‐comparison study based on statistic tests was applied to determine the optimal configuration for each technique. According to the results, support vector machines became a suitable and reliable technique to be applied in the modelling of the breakdown potential of austenitic stainless steels. This technique outperformed the models based on artificial neural networks and provided a useful tool to compare the pitting corrosion resistance of stainless steel in different environmental conditions without recourse to polarization tests. Therefore, this model presented a relevant meaning in science and engineering applications. Copyright © 2014 John Wiley & Sons, Ltd.
Organoclays as Sorbent Material for Phenolic Compounds: A Review
Authors: Nafees Muhammad , Waseem Amir
Published: January 2014

The quest for new adsorbing material directed several scientists for more efficient sorbent material for environmental remediation. Natural materials such as clays are good sorbents for many contaminants in soil and water; due to their availability, low cost, environmental stability and high adsorptive, and ion exchange properties. Clay materials can potentially be modified by introducing long or short chain organic compounds to achieve the desired surface properties for best immobilization of hydrophobic compounds. Modified clays obtained are called organoclays and have been proven effective for remediation of many contaminants in soil and water such as phenols and its derivatives. This paper will highlight the synthesis, mechanism of sorption, isotherm models, and the applications of organoclays as potential sorbents for the environmental remediation of phenol and its derivatives. By looking at all the above as well as the detailed literature survey, we conclude that organoclays are cost effective sorbent material that have a high removal potential for phenol and its derivatives from water and wastewater.
Strain mapping for advanced CMOS technologies
Authors: Özdöl V. B. , Tyutyunnikov D. , Koch C. T. , van Aken P. A.
Published: January 2014

The ability to measure strain quantitatively has become an important tool for characterizing strain‐engineered CMOS devices. We report on nanometer scale strain measurements performed on off‐the‐shelf 32‐nm node device structures. We show that the two‐dimensional deformation tensor in NMOS channels can be mapped using high resolution transmission electron microscopy. We also demonstrate the application of our recently developed dark‐field inline holography technique on an array of PMOS transistors, showing that this technique is capable of combining a large field of view of 1 micrometer with a spatial resolution better than 1 nm, and very high precision (around 10−4). Also, the experimental requirements for implementing this technique are easily met on most modern TEMs, without any modification to the hardware or alignment of the microscope.
End‐of‐Life Treatment of Poly(Vinyl Chloride) and Chlorinated Polyethylene by Dehydrochlorination in Ionic Liquids
Authors: Glas Daan , Hulsbosch Joris , Dubois Philippe , Binnemans Koen , De Vos Dirk E.
Published: January 2014

There is an urgent need for green technologies to remove halogens from halogenated polymers at the end of their lifetime. Ionic liquids (ILs) were used to dehydrochlorinate and/or dissolve the chlorinated polymers poly(vinyl chloride) (PVC) and chlorinated polyethylene (CPE). The dehydrochlorination activity of an IL depends mainly on its anion and is related to the high hydrogen‐bond‐accepting ability (β value) of the anion. Different phosphonium ILs successfully dissolve and dehydrochlorinate PVC and CPE at temperatures from 80 °C. PVC is dehydrochlorinated up to 98 % after 60 min in tetrabutylphosphonium chloride ([P4444][Cl]) at 180 °C. PVC pieces stabilized by calcium stearate (4 mm3) are dehydrochlorinated more slowly; conversions of 85 and 96 % are reached after 1 and 8 h, respectively. Smaller pieces are dehydrochlorinated faster. High loadings, for example, 0.3 g stabilized PVC in 0.5 g IL, can be applied with only a minor loss of conversion. [P4444][Cl] proved to be stable during several consecutive reactions; after each run more than 99 % of the IL can be recovered. The structure of the dehydrochlorinated PVC was studied by 13C cross‐polarization magic‐angle spinning NMR and FTIR spectroscopy; the removal of Cl and the formation of double bonds were confirmed. Carefully dehydrochlorinated CPE was processed further by acyclic diene metathesis depolymerization with ethylene and the Hoveyda–Grubbs second‐generation catalyst to yield α,ω‐dienes such as 1,5‐hexadiene and 1,6‐heptadiene.
Benzochalcogenodiazole‐Based Donor–Acceptor–Acceptor Molecular Donors for Organic Solar Cells
Authors: Ting Hao‐Chun , Chen Yi‐Hong , Lin Li‐Yen , Chou Shu‐Hua , Liu Yi‐Hung , Lin Hao‐Wu , Wong Ken‐Tsung
Published: January 2014

Four new molecules with a donor–acceptor–acceptor (D‐A‐A) configuration, in which 2,1,3‐benzoxadiazole or 2,1,3‐benzoselenodiazole were adopted as the central bridging acceptor, were synthesized as electron donors for small‐molecule organic solar cells. In conjunction with two previously reported 2,1,3‐benzothiadiazole‐based compounds, the influences of the benzochalcogenodiazole acceptor unit and the ditolylarylamine donor moiety on the molecular structure, electrochemical behavior, and optical properties of the materials were investigated systematically to obtain a clear structure–property relationship. Vacuum‐deposited hybrid planar mixed‐heterojunction devices fabricated with the new donors and C70 as the acceptor showed power conversion efficiencies in the range of 2.9–4.3 % under 1 sun (100 mW cm−2) AM 1.5 G simulated solar illumination. The current density–voltage characteristics of solar cells at various light intensities were measured, which revealed a high bimolecular recombination.
High performance 8 bit cascaded carry look ahead adder with precise power consumption
Authors: Johri Raj , Akashe Shyam , Sharma Sanjay
Published: January 2014

Multiple bit adders like ripple carry adder make the propagation of carry bit very slow and this is the reason why it must be replaced with fast adders as carry‐look‐ahead adder (CLA). Power consumption in digital circuits depends on the number of metal–oxide–semiconductor field‐effect transistor employed and various other parameters. If number of metal–oxide–semiconductor field‐effect transistor is reduced the power consumption would definitely be reduced. Conventional CLAs would consume significant amount of power that still needs to be improved. The paper here deals with the implementation of 8 bit CLA with the aim of reducing the size and to precise the power consumption within nanowatt range, by improving the fundamental components of the circuit. All the parameters have been calculated by using Cadence Virtuoso tool at 45 nm technology. Copyright © 2014 John Wiley & Sons, Ltd.
A content analysis of healthy living blogs: Evidence of content thematically consistent with dysfunctional eating attitudes and behaviors
Authors: Boepple Leah , Thompson Joel Kevin
Published: January 2014

Objective

“Healthy” living blogs are a recent addition to internet media that offer advice on improving physical and mental health. Often, these sites include information on eating, exercise, and self‐image. This study was a content analysis designed to evaluate the information included on these sites.

Method

A sample of 21 blogs was selected from a larger sample for evaluation. These blogs were chosen based on two criteria: they had won an award for healthy blogs and they had a large number of pageviews (pageviews were calculated using a web analytics website). Two raters (kappa reliability = 0.82) rated these blogs on multiple variables related to the blogger's characteristics, the content provided by the blogger, and entries posted on the blog.

Results

Five of the bloggers self‐identified as having had an eating disorder; seven mentioned difficulties with either menstruation or fertility; 11 referenced being on a diet; five indicated that they were using some form of dietary restraint; and 11 included some form of written negative/guilt‐inducing message about food. Blog entries and About Me sections contained a variety of content indicative of problematic eating and body image information.

Discussion

These findings suggest the content of healthy living blogs might be problematic for viewers who have eating or body image issues. The content does not approach the inflammatory nature of pro‐eating disorder websites, yet information promoted clearly indicates that future research should further evaluate these sites. © 2014 Wiley Periodicals, Inc. (Int J Eat Disord 2014; 47:362–367)
Clonotype‐specific avidity influences the dynamics and hierarchy of virus‐specific regulatory and effector CD4+T‐cell responses
Authors: Liu Jie , Cao Shirley , Peppers Gretchen , Kim Sung‐Han , Graham Barney S.
Published: January 2014

A key component of immunity against viruses, CD4+ T cells expand and differentiate into functional subsets upon primary infection, where effector (Teff) cells facilitate infection control and regulatory (Treg) cells mitigate immunopathology. After secondary infection, Teff cells mount a robust response from the memory pool. Here, we show that Treg‐cell responses are diminished upon secondary infection, and Treg‐cell response dynamics are associated more with T‐cell receptors (TCRs) repertoire and avidity than with epitope specificity. In the murine model, the IAbM209 epitope of respiratory syncytial virus is recognized by both CD4+ Treg and Teff cells, while the IAbM226 epitope is recognized almost exclusively by CD4+ Teff cells expressing high avidity TCR Vβ8.1/8.2 and dominating the CD4+ T‐cell response during primary and secondary infections. IAbM209‐Teff cells express relatively low avidity TCRs during early primary infection, but high avidity TCR Vβ7‐expressing IAbM209‐Teff cells emerge during the late phase, and become dominant after secondary infection. The emerging high avidity IAbM209‐Teff cells outcompete IAbM209‐Treg cells that share the same epitope, but have low avidity and are restricted to TCR Vβ2 and Vβ6 subpopulations. These data indicate that MHC‐peptide‐TCR interactions can produce different kinetic and functional profiles in CD4+ T‐cell populations even when responding to the same epitope.
Pilot‐scale processing with alkaline pulping and enzymatic saccharification for bioethanol production from rice straw
Authors: Sekine Motoi , Ogawa Yukiharu , Matsuoka Nobuhiro , Izumi Yoshiya
Published: January 2014

We examined pilot‐scale bioethanol production from rice straw using sodium carbonate pulping as the alkaline pulping method and enzymatic saccharification. The yield of prewashed rice straw after the crushing and prewashing stage decreased with an increase in the input in rice straw. The pulp yield after alkaline cooking was 66–68% at kappa number ranging from 32 to 36, which was comparatively higher than the laboratory‐scale study. The yield of enzymatic saccharized glucose was decreased with the increase in washed pulp and its saccharification rate was approximately 20%. We successfully produced approximately 100 liters of 95% ethanol from 1000 Bone‐Dry kg (BDkg) rice straw. The results of our pilot‐scale study indicated that the relationship between resource input and product yield for each operation exhibited exponential or logarithmic curves, rather than linear decreases or increases, which could suggest a high‐cost structure for bioethanol production when the resource input is larger. However, we established an optimum quantity of resource input, approximately 2000–3000 BDkg in our pilot‐scale study, for higher efficiencies.
Variants of the inosine triphosphate pyrophosphatase gene are associated with reduced relapse risk following treatment for HCV genotype 2/3
Authors: Rembeck Karolina , Waldenström Jesper , Hellstrand Kristoffer , Nilsson Staffan , Nyström Kristina , Martner Anna , Lindh Magnus , Norkrans Gunnar , Westin Johan , Pedersen Court , Färkkilä Martti , Langeland Nina , Buhl Mads Rauning , Mφrch Kristine , Christensen Peer Brehm , Lagging Martin
Published: January 2014

The present study evaluated the impact of variations in the inosine triphosphate pyrophosphatase (ITPase) gene (ITPA) on treatment outcome in patients with hepatitis C virus (HCV) genotype 2/3 infection receiving peginterferon-α2a and lower, conventional 800 mg daily dose of ribavirin. Previous studies using higher, weight-based ribavirin dosing report that patients carrying polymorphisms encoding reduced predicted ITPase activity show decreased risk of ribavirin-induced anemia but increased risk of thrombocytopenia, with no impact on elimination of virus. In all, 354 treatment-naïve HCV genotype 2/3-infected patients, enrolled in a phase III trial (NORDynamIC), were genotyped for ITPA (rs1127354 and rs7270101). Homo- or heterozygosity at A
rs1127354
or C
rs7270101
, entailing reduced ITPase activity, was observed in 37% of patients and was associated with increased likelihood of achieving sustained virological response (SVR) (P = 0.0003 in univariate and P = 0.0002 in multivariate analyses) accompanied by a reduced risk of relapse among treatment-adherent patients. The association between ITPA variants and SVR remained significant when patients were subdivided by the 12- and 24-week treatment duration arms, HCV genotype, fibrosis stage, and IL28B genotype, and was not secondary to improved adherence to therapy or less pronounced anemia. Gene variants predicting reduced predicted ITPase activity were also associated with decreased risk of anemia (P < 0.0001), increased risk of thrombocytopenia (P = 0.007), and lower ribavirin concentrations (P = 0.02). Conclusion: These findings demonstrate a novel ribavirin-like association between polymorphisms at ITPA and treatment efficacy in chronic hepatitis C mediated by reduced relapse risk. We hypothesize that patients (63%) being homozygous for both major alleles, leading to normal ITPase activity, may benefit more from the addition of ribavirin to present and future treatment regimens for HCV in spite of concomitant increased risk of anemia. (Hepatology 2014;59:2131–2139)
Cost-Effectiveness of Sofosbuvir-Based Triple Therapy for Untreated Patients With Genotype 1 Chronic Hepatitis C
Authors: Petta Salvatore , Cabibbo Giuseppe , Enea Marco , Macaluso Fabio Salvatore , Plaia Antonella , Bruno Raffaele , Gasbarrini Antonio , Craxì Antonio , Cammà Calogero
Published: January 2014

We assessed the cost-effectiveness of sofosbuvir (SOF)-based triple therapy (TT) compared with boceprevir (BOC)- and telaprevir (TVR)-based TT in untreated genotype 1 (G1) chronic hepatitis C (CHC) patients discriminated according to IL28B genotype, severity of liver fibrosis, and G1 subtype. The available published literature provided the data source. The target population was made up of untreated Caucasian patients, aged 50 years, with G1CHC and these were evaluated over a lifetime horizon by Markov model. The study was carried out from the perspective of the Italian National Health Service. Outcomes included discounted costs (in euros at 2013 value), life-years gained (LYG), quality-adjusted life year (QALY), and incremental cost-effectiveness ratio (ICER). Cost of SOF was assumed to be €3,500 per week, i.e., the price generating a willingness-to-pay threshold of €25,000 per LYG compared with TVR in the entire population of untreated G1 patients. The robustness of the results was evaluated by one-way deterministic and multivariate probabilistic sensitivity analyses. SOF was cost-effective compared with BOC in all strategies with the exception of cirrhosis and IL28B CC patients. In comparison with TVR-based strategies, SOF was cost-effective in IL28B CT/TT (ICER per LYG €22,229) and G1a (€19,359) patients, not cost-effective in IL28B CC (€45,330), fibrosis F0-F3 (€26,444), and in cirrhosis (€34,906) patients, and dominated in G1b patients. The models were sensitive to SOF prices and to likelihood of sustained virological response.

Conclusion:

In untreated G1 CHC patients, SOF-based TT may be a cost-effective alternative to first-generation protease inhibitors depending on pricing. The cost-effectiveness of SOF improved in IL28B CT/TT and G1a patients. SOF was dominated by TVR in G1b patients even if, in clinical practice, this issue could be counterbalanced by the good tolerability profile of SOF and by the shorter treatment duration. (Hepatology 2014;59:1692–1705)