bluuebunny/crossref_metadata_2025_split huggingface dataset:
Click chemistry in materials synthesis. III. Metal‐adhesive polymers from Cu(I)‐catalyzed azide–alkyne cycloaddition
Authors: Liu Yi , Díaz David D. , Accurso Adrian A. , Sharpless K. Barry , Fokin Valery V. , Finn M. G. 
Published: October 2007

Abstract1,2,3‐Triazole‐based polymers generated from the Cu(I)‐catalyzed cycloaddition between multivalent azides and acetylenes are effective adhesive materials for metal surfaces. The adhesive capacities of candidate mixtures of azide and alkyne components were measured by a modified peel test, using a customized adhesive tester. A particularly effective tetravalent alkyne and trivalent azide combination was identified, giving exceptional strength that matches or exceeds the best commercial formulations. The addition of Cu catalyst was found to be important for the synthesis of stronger adhesive polymers when cured at room temperature. Heating also accelerated curing rates, but the maximum adhesive strengths achieved at both room temperature and high temperature were the same, suggesting that crosslinking reaches the same advanced point in all cases. Polytriazoles also form adhesives to aluminum, but copper is bound more effectively, presumably because active Cu(I) ions may be leached from the surface to promote crosslinking and adhesion. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5182–5189, 2007
Amphiphilic PEG/alkyl‐grafted comb polylactides
Authors: Jiang Xuwei , Vogel Erin B. , Smith Milton R. , Baker Gregory L. 
Published: October 2007

AbstractAmphiphilic polylactides (PLAs) with well‐defined architectures were synthesized by ring‐opening polymerization of AB monomers (glycolides) substituted with both a long chain alkyl group and a triethylene glycol segment terminated in either a methyl or benzyl group. The resulting amphiphilic PLAs had number average molecular weights >100,000 g/mol. DSC analysis revealed a first‐order phase transition at ∼ 20 °C, reflecting the crystalline nature of the linear alkyl side chains. Polymeric micelles were prepared by the solvent displacement method in water. Dynamic light scattering measurements support formation of a mixture of 20‐nm‐diameter unimolecular micelles and 60‐nm particles comprised of an estimated 25 polymer molecules. UV–vis characterization of micelles formed from acetone–water solutions containing azobenzene confirmed encapsulation of the hydrophobic dye, suggesting their potential as new amphiphilic PLAs as drug delivery vehicles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5227–5236, 2007
Novel multiblock‐co‐ionomers as potential polymer electrolyte membrane materials
Authors: Schönberger Frank , Kerres Jochen 
Published: October 2007

AbstractIn this contribution a series of novel multiblock‐co‐ionomers consisting of hydrophobic (partially fluorinated) and hydrophilic (sulfonated) domains has been prepared and characterised in terms of their applicability as fuel cell membranes. The synthesis of these multiblock‐co‐ionomers is a four‐step procedure including (1) the sulfonation of the monomer 4,4′‐difluorodiphenylsulfone, (2) the preparation of hydrophilic telechelic macromonomers by molecular‐weight controlled step‐growth polycondensation of the sulfonated monomer with various bis(thio)phenols, (3) the preparation of a hydrophobic telechelic macromonomer and (4) the coupling of both telechelic macromonomers to yield microphase‐separated block‐co‐ionomers. This study focuses on the investigation of the influence of various linkage groups and atoms within the hydrophilic domains of the multiblock‐co‐ionomers. Both the telechelic macromonomers and the multiblock‐co‐ionomers were structurally investigated by 1H‐ and 19F‐NMR spectroscopy and gel permeation chromatography (GPC). All multiblock‐co‐ionomers of this series could be cast into membranes and their membrane properties (ion‐exchange capacity, specific resistance, swelling ratio, water uptake, thermal and oxidative stability) were measured and discussed in dependence of the various linkage groups within the hydrophilic domains. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5237–5255, 2007
Synthesis, characterization, and photovoltaic properties of novel conjugated copolymers derived from phenothiazines
Authors: Tang Weihua , Kietzke Thomas , Vemulamada Pardhasaradhi , Chen Zhi‐Kuan 
Published: October 2007

AbstractTwo novel series of soluble alternating conjugated copolymers comprising 10‐alkylphenothiazine and bithiophene or 3‐pentylthieno[3,2‐b]thiophene moieties were synthesized using palladium‐catalyzed Suzuki coupling reaction. The structures of the polymers and their thermal, photophysical, electrochemical, and photovoltaic properties were characterized and investigated. The polymers exhibited good thermal stability with decomposition temperature in the region of 342–390 °C and their glass transition temperatures (Tg) ranging from 126 to 150 °C. All polymers demonstrate broad optical absorption in the region of 300–500 nm with efficient blue‐green light emission. They showed ambipolar redox properties with low HOMO levels around −5.13 eV. Polymer solar cells were fabricated using blends of the copolymers and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) in a 1:1 weight ratio. The maximum power conversion efficiency (η = 0.24%) was measured for the poly[3,7‐ (10‐hexylphenothiazine)‐alt‐bithiophene] as donor under simulated sun light (1000 W/m2). Open circuit voltages of up to 0.8 V have been obtained. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5266–5276, 2007
Energetics of protein homodimerization: Effects of water sequestering on the formation of β‐lactoglobulin dimer
Authors: Bello Martiniano , Pérez‐Hernández Gerardo , Fernández‐Velasco D. Alejandro , Arreguín‐Espinosa Roberto , García‐Hernández Enrique 
Published: October 2007

AbstractTransient protein–protein interactions are functionally relevant as a control mechanism in a variety of biological processes. Analysis of the 3D structure of protein–protein complexes indicates that water molecules trapped at the interface are very common; however, their role in the stability and specificity of protein homodimer interactions has been not addressed yet. To provide new insights into the energetic bases that govern the formation of highly hydrated interfaces, the dissociation process of bovine βlg variant A at a neutral pH was characterized here thermodynamically by conducting dilution experiments with an isothermal titration calorimeter. Association was enthalpically driven throughout the temperature range spanned. ΔH and ΔCp were significantly more negative than estimates based on surface area changes, suggesting the occurrence of effects additional to the dehydration of the contact surfaces between subunits. Near‐UV CD spectra proved to be independent of protein concentration, indicating a rigid body‐like association. Furthermore, the process proved not to be coupled to significant changes in the protonation state of ionizable groups or counterion exchange. In contrast, both osmotic stress experiments and a computational analysis of the dimer's 3D structure indicated that a large number of water molecules are incorporated into the interface upon association. Numerical estimates considering the contributions of interface area desolvation and water immobilization accounted satisfactorily for the experimental ΔCp. Thus, our study highlights the importance of explicitly considering the effects of water sequestering to perform a proper quantitative analysis of the formation of homodimers with highly hydrated interfaces. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Molecular dynamics simulation study for LRH‐1: Interaction with fragments of SHP and function of phospholipid ligand
Authors: Zhang Tao , Zhou Jun‐Hong , Shi Liang‐Wei , Zhu Rui‐Xin , Chen Min‐Bo 
Published: October 2007

AbstractThe liver receptor homolog‐1 (LRH‐1) is an important transcriptional factor in the process of cholesterol and bile acids metabolism. In this article, molecular dynamics simulation for six systems with total 60 ns is employed to study LRH‐1. LRH‐1/phospholipid and LRH‐1/SHP (fragments) interactions are analyzed by counting atomic contact number, identifying hydrogen bonds, and estimating binding free energies (by MM‐PB/SA and N‐mode analysis). Through integrating our modeling result with previous experimental data, deeper understandings to LRH‐1/SHP interaction are obtained, and functions of the phospholipid ligand in LRH‐1 are proposed. Proteins 2008. © 2007 Wiley‐Liss, Inc.
A knowledge‐based forcefield for protein–protein interface design
Authors: Clark Louis A. , van Vlijmen Herman W. T. 
Published: October 2007

AbstractA distance‐dependent knowledge‐based potential for protein–protein interactions is derived and tested for application in protein design. Information on residue type specific Cα and Cβ pair distances is extracted from complex crystal structures in the Protein Data Bank and used in the form of radial distribution functions. The use of only backbone and Cβ position information allows generation of relative protein–protein orientation poses with minimal sidechain information. Further coarse‐graining can be done simply in the same theoretical framework to give potentials for residues of known type interacting with unknown type, as in a one‐sided interface design problem. Both interface design via pose generation followed by sidechain repacking and localized protein–protein docking tests are performed on 39 nonredundant antibody–antigen complexes for which crystal structures are available. As reference, Lennard–Jones potentials, unspecific for residue type and biasing toward varying degrees of residue pair separation are used as controls. For interface design, the knowledge‐based potentials give the best combination of consistently designable poses, low RMSD to the known structure, and more tightly bound interfaces with no added computational cost. 77% of the poses could be designed to give complexes with negative free energies of binding. Generally, larger interface separation promotes designability, but weakens the binding of the resulting designs. A localized docking test shows that the knowledge‐based nature of the potentials improves performance and compares respectably with more sophisticated all‐atoms potentials. Proteins 2008. © 2007 Wiley‐Liss, Inc.
A general approach for developing system‐specific functions to score protein–ligand docked complexes using support vector inductive logic programming
Authors: Amini Ata , Shrimpton Paul J. , Muggleton Stephen H. , Sternberg Michael J. E. 
Published: October 2007

AbstractDespite the increased recent use of protein–ligand and protein–protein docking in the drug discovery process due to the increases in computational power, the difficulty of accurately ranking the binding affinities of a series of ligands or a series of proteins docked to a protein receptor remains largely unsolved. This problem is of major concern in lead optimization procedures and has lead to the development of scoring functions tailored to rank the binding affinities of a series of ligands to a specific system. However, such methods can take a long time to develop and their transferability to other systems remains open to question. Here we demonstrate that given a suitable amount of background information a new approach using support vector inductive logic programming (SVILP) can be used to produce system‐specific scoring functions. Inductive logic programming (ILP) learns logic‐based rules for a given dataset that can be used to describe properties of each member of the set in a qualitative manner. By combining ILP with support vector machine regression, a quantitative set of rules can be obtained. SVILP has previously been used in a biological context to examine datasets containing a series of singular molecular structures and properties. Here we describe the use of SVILP to produce binding affinity predictions of a series of ligands to a particular protein. We also for the first time examine the applicability of SVILP techniques to datasets consisting of protein–ligand complexes. Our results show that SVILP performs comparably with other state‐of‐the‐art methods on five protein–ligand systems as judged by similar cross‐validated squares of their correlation coefficients. A McNemar test comparing SVILP to CoMFA and CoMSIA across the five systems indicates our method to be significantly better on one occasion. The ability to graphically display and understand the SVILP‐produced rules is demonstrated and this feature of ILP can be used to derive hypothesis for future ligand design in lead optimization procedures. The approach can readily be extended to evaluate the binding affinities of a series of protein–protein complexes. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Recent advances in application of acoustic, acousto‐optic and photoacoustic methods in biology and medicine
Authors: Chivukula Venkata S. , Shur Michael S. , Čiplys Daumantas 
Published: October 2007

AbstractVarious types of acoustic wave devices based on surface acoustic, acousto‐optic and photoacoustic effects are increasingly used for many biomedical applications. This paper reviews the basic physical phenomena of the acoustic wave propagation and photoacoustic and acousto‐optic interactions, which determine their sensing capabilities, and discusses recent applications of these devices in biology and medicine. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Random partitions with restricted part sizes
Authors: Goh William M.Y. , Hitczenko Pawel 
Published: October 2007

AbstractFor a subset $\cal{S}$ of positive integers let Ω(n,$\cal{S}$) be the set of partitions of n into summands that are elements of $\cal{S}$. For every λ ∈ Ω(n,$\cal{S}$), let Mn(λ) be the number of parts, with multiplicity, that λ has. Put a uniform probability distribution on Ω(n,$\cal{S}$), and regard Mn as a random variable. In this paper the limiting density of the (suitably normalized) random variable Mn is determined for sets that are sufficiently regular. In particular, our results cover the case $\cal{S}$ = {Q(k) : k ≥ 1}, where Q(x) is a fixed polynomial of degree d ≥ 2. For specific choices of Q, the limiting density has appeared before in rather different contexts such as Kingman's coalescent, and processes associated with the maxima of Brownian bridge and Brownian meander processes. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008
Practical experiences on the necessity of external validation
Authors: König I. R. , Malley J. D. , Weimar C. , Diener H.‐C. , Ziegler A. 
Published: October 2007

AbstractThe validity of prognostic models is an important prerequisite for their applicability in practical clinical settings. Here, we report on a specific prognostic study on stroke patients and describe how we explored the prediction performance of our model. We considered two practically highly relevant generalization aspects, namely, the model's performance in patients recruited at a later time point (temporal transportability) and in medical centers different from those used for model building (geographic transportability). To estimate the accuracy of the model, we investigated classical internal validation techniques and leave‐one‐center‐out cross validation (CV). Prognostic models predicting functional independence of stroke patients were developed in a training set using logistic regression, support vector machines, and random forests (RFs). Tenfold CV and leave‐one‐center‐out CV were employed to estimate temporal and geographic transportability of the models. For temporal and external validation, the resulting models were used to classify patients from a later time point and from different clinics. When applying the regression model or the RFs, accuracy in the temporal validation data was well predicted from classical internal validation. However, when predicting geographic transportability all approaches had difficulties. We observed that the leave‐one‐center‐out CV yielded better estimates than classical CV. On the basis of our results, we conclude that external validation in patients from different clinics is required before a prognostic model can be applied in practice. Even validating the model in patients recruited merely at a later time point does not suffice to predict how it may fare with regard to another clinic. Copyright © 2007 John Wiley & Sons, Ltd.
Baseline and treatment effect heterogeneity for survival times between centers using a random effects accelerated failure time model with flexible error distribution
Authors: Komárek Arnošt , Lesaffre Emmanuel , Legrand Catherine 
Published: October 2007

AbstractNowadays, most clinical trials are conducted in different centers and even in different countries. In most multi‐center studies, the primary analysis assumes that the treatment effect is constant over centers. However, it is also recommended to perform an exploratory analysis to highlight possible center by treatment interaction, especially when several countries are involved. We propose in this paper an exploratory Bayesian approach to quantify this interaction in the context of survival data. To this end we used and generalized a random effects accelerated failure time model. The generalization consists in using a penalized Gaussian mixture as an error distribution on top of multivariate random effects that are assumed to follow a normal distribution. For computational convenience, the computations are based on Markov chain Monte Carlo techniques. The proposed method is illustrated on the disease‐free survival times of early breast cancer patients collected in the EORTC trial 10854. Copyright © 2007 John Wiley & Sons, Ltd.
An MDA‐based approach for database re‐engineering
Authors: Polo Macario , García‐Rodríguez Ignacio , Piattini Mario 
Published: October 2007

AbstractThis article presents the technical and functional descriptions of a tool specifically designed for database re‐engineering. As is well known, re‐engineering is the process of (1) applying reverse engineering to a software product to obtain higher‐level specifications and (2) using these specifications as the starting point for the development of a new version of the system. Thus, the complete process can be seen as a sequence of transformation functions that operate on the different sets involved in the whole process. The starting point of the re‐engineering process is the physical schema of the database which is translated into a vendor‐independent metamodel (the logical schema) and then translated into a class diagram representing a possible conceptual schema of the database. This diagram is then taken as the starting point for the code generation process, which produces an executable application for four possible different platforms. Copyright © 2007 John Wiley & Sons, Ltd.
Towards complex holism
Authors: Dongping Fan 
Published: October 2007

AbstractThis paper presents an inter‐level causal view of complex systems. It argues the need to go beyond causal reductionism, the limitations of the model of theory reduction in understanding and explaining the behaviour of complex systems, and the incompleteness of individualism methodology in explaining complex social organizational behaviours. It proposes a multi‐level and multi‐dimensional co‐evolutionary ‘complex holism’ to provide a new prospective for understanding organizational evolution and management. Copyright © 2007 John Wiley & Sons, Ltd.
Complexity science, systems thinking and pragmatic sensibility
Authors: Zhichang Zhu 
Published: October 2007

AbstractThis paper examines mainstream complexity management writings, presents a radical alternative proposed by Ralph Stacey and his colleagues, explores some tensions in that alternative and analyzes Stacey's criticism on systems thinking. The paper proposes that a pragmatic sensibility is particularly useful for transferring radical insights from complexity sciences into studies of organisation change and management. Copyright © 2007 John Wiley & Sons, Ltd.
Innovative Wege im Verbundbrückenbau
Authors: Dorrer Günther 
Published: October 2007

AbstractIm Zuge der Einführung der vom Bundesministerium für Verkehr, Bau‐ und Wohnungswesen (BMVBW) in Auftrag und vom Deutschen Institut für Normung herausgegebenen DIN‐Fachberichte wurden von der DEGES in den letzten Jahren mehrere Projekte als Pilotprojekte realisiert.Eines dieser ausgewählten Projekte ist die im Zuge der BAB A 73 nördlich von Schleusingen errichtete 448 m lange Talbrücke St. Kilian. Mit ihrem markanten Design setzt sie ein deutliches Zeichen für den Willen der DEGES, architektonisch gestaltete Ingenieurbauwerke zu errichten. Neben der Gestaltung spiegeln die eingesetzten Baustoffe und die Ausführungsmethodik die innovativen Wege im Verkehrsbrückenbau wider, die von Bauherren, Ingenieurbüros und Firmen beschritten werden sollen.
Rekonstruktion von Barockspiegeln des Historischen Grünen Gewölbes im Dresdener Schloss
Authors: Neodon Wolfgang , Zywitzki Olaf , Kopte Torsten 
Published: October 2007

AbstractAm 1. September 2006 eröffnete die Bundeskanzlerin Frau Dr. Angela Merkel das rekonstruierte Historische Grüne Gewölbe, die Schatzkammer der sächsischen Kurfürsten und Könige, im Dresdener Residenzschloss. Seit dessen Zerstörung am 13. Februar 1945 haben zwei Generationen wissenschaftlich‐künstlerischen Vorlauf geschaffen, um den Wiederaufbau zu ermöglichen.Die Idee des barocken Spiegelkabinetts war im Grünen Gewölbe erstmalig auf eine Folge von 8 Räumen übertragen worden. Die originalen Spiegel, mit Zinnamalgam belegt, besitzen einen deutlich geringeren Reflexionsgrad als moderne Silberspiegel. Von ursprünglich 423 m2 Spiegelfläche konnten jedoch nur noch 60 m2 wiederverwendet werden. Für die Restaurierung und Rekonstruktion der ursprünglichen Verspiegelungen waren umfangreiche analytische Untersuchungen erforderlich, mit der das Sächsische Immobilien‐ und Baumanagement (SIB) das Fraunhofer‐Institut für Elektronenstrahl‐ und Plasmatechnik (FEP) beauftragte. Auf Grundlage der Ergebnisse wurde von der zuständigen Gestaltungskommission entschieden, fehlende Spiegel zwischen originalem Bestand in historischer Zinnamalgam‐Verspiegelungstechnologie herzustellen. Die Rekonstruktion des völlig zerstörten Juwelenzimmers mit partiell goldradierten Spiegeln sollte jedoch aus arbeitshygienischen und zeitlichen Gründen mittels einer quecksilberfreien Vakuum ‐ Dünnschicht ‐ Technologie, dem Magnetron‐Sputtern, erfolgen. Die Ergebnisse zeigen, dass ein Schichtsystem Zinn‐Bronze‐Titan mit Schutzlackierung einen adäquaten Ersatz für die originalen Zinnamalgamspiegel darstellt.Das Verfahren ermöglicht relativ unkompliziert Teilverspiegelungen und nachträgliches Einfügen von künstlerischen Goldradierungen.
Haftfeste Metallisierung von Filtermedien mit Vakuum‐Arc‐Technologie
Authors: Schmalz Elke , Zimmer Otmar 
Published: October 2007

AbstractZur Abscheidung von Schadstoffen aus Prozessgasen bei höheren Temperaturen werden textile Filtermedien aus Hochleistungsfasern eingesetzt. Für die häufig geforderte antistatische Ausrüstung dieser Materialien eignet sich die Metallisierung mittels Vakuum‐Arc‐Verfahren. Derart hergestellte Metallisierungen sind extrem haftfest, sehr gut leitfähig und beeinträchtigen den Gasdurchsatz nicht. Eine industrielle Umsetzung der Ergebnisse erscheint für viele Anwendungen sinnvoll.