bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nickel‐Catalyzed Cross‐Coupling of Non‐activated and Functionalized Alkyl Halides with Alkyl Grignard Reagents
Authors: Vechorkin Oleg , Hu Xile 
Published: January 2009

AbstractReacting in the 'Ni'ck of time: The title reaction is realized by using an isolated NiII complex (1). The catalysis tolerates a wide range of important functional groups that are often incompatible with Grignard reagents in cross‐coupling reactions.magnified image
Engineering performance and material viscoelastic analyses along a compounding line for silica‐based compounds, part 2: Nonlinear viscoelastic analysis
Authors: Leblanc J. L. , Nijman G. 
Published: January 2009

AbstractIn the first part of this article, a mixing line for silica‐based compounds was thoroughly described and its performance was studied in terms of mixing fingerprints. Along the mixing line, the compound experiences a large spectrum of strain, stress and temperature conditions such that important “cascade” or “stream” effects occur. At a given point of the process, the material has an important strain‐stress‐temperature history that is obviously affecting its behavior during the subsequent steps, and the situation is further complicated by the in situ silanisation, which obviously must be complete for stabilized rheological properties to be obtained at the end of the line. In this second part of the article, results are reported which were obtained with a new and promising rheometrical technique, i.e., the so‐called Fourier Transform rheometry, implemented on a commercial torsional dynamic rheometer. As shown, Fourier Transform (FT) rheometry provides a number of information about the complex set of events that occur along the silica‐silane mixing line. Odd torque harmonics become significant as strain increases, and therefore the variation of torque harmonics with strain amplitude can be considered as the nonlinear viscoelastic “signature” of tested materials. Silica filled materials exhibit also a typical pattern, with a “bump” appearing in the 500% strain range, essentially on the third relative harmonic versus strain curves and changing as optimal silica dispersion and silinisation are achieved. The appropriate modeling of experimental results provide parameters with typical variations along the mixing line which are interpreted with respect to current views on the in situ silanisation process and are found in line with the mixing signatures analysis. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Epoxy networks for medicine applications: Mechanical properties and in vitro biological properties
Authors: Garcia Filiberto González , Elena Leyva Maria , Alencar de Queiroz Alvaro Antonio , Zazuco Higa Olga 
Published: January 2009

AbstractThis work describes the physicochemical, mechanical, and in vitro biological properties of three epoxy networks based on diglycidyl ether of bisphenol‐A (DGEBA) epoxy prepolymer cured with triethylenetetramine, 1‐(2‐aminoethyl)piperazine (AEP) and isophoronediamine. The mechanical properties were evaluated with respect to impact and flexural tests. Functionality rules the mechanical behavior of epoxy networks by increasing the crosslink density and the flexural modulus, increasing Tg and decreasing the chain flexibility and the impact resistance. The biological interactions between the obtained epoxy polymers and blood were studied by in vitro methods. Studies on the protein adsorption, platelet adhesion, and thrombus formation are presented. The protein adsorption assays onto polymeric surfaces showed that the epoxy networks adsorbed more albumin than fibrinogen. The results about platelet adhesion and thrombus formation indicated that DGEBA‐IPD and DGEBA‐AEP networks exhibits good hemocompatible behavior. The materials revealed no signs of cytotoxicity to Chinese hamster ovary cells, showing a satisfactory cytocompatibility. In this way, we can assume that the epoxy polymers are biocompatible materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
New poly(arylene ether)s containing phthalimidine group in the main chain
Authors: Aggarwal Mohit , Maji Samarendra , Kumar Sen Suman , Dasgupta Barnali , Chatterjee Shyambo , Ghosh Anindita , Banerjee Susanta 
Published: January 2009

AbstractFive new poly(arylene ether)s containing phthalimidine group in the main chain and pendent trifluoromethyl group have been prepared by the reaction of 4,4′‐(bis‐4‐fluoro‐3‐trifluoromethylphenyl)benzene (BTF) with bisphenols. Different molar ratios of N‐phenyl‐3,3‐bis(4‐hydroxyphenyl)phthalimidine (PA) and 4,4′‐isopropylidenediphenol (BPA) have been used to generate different copolymers. The polymers obtained by step growth polymerization exhibited weight‐average molecular weight upto 134,000 g/mol with a polydispersity index of 2.1–2.4. The homopolymer from BTF and PA showed very high glass transition temperature of 258°C and outstanding thermal stability upto 536°C for 5% weight loss under nitrogen. The polymers were soluble in a wide range of organic solvents. Transparent thin films of these polymers exhibited tensile strengths upto 65 MPa and elongation at break upto 45% depending on the exact repeat unit structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Radiation grafting of acrylic acid onto poly(ethylene terephthalate) fabric
Authors: Gupta Bhuvanesh , Grover Navdeep , Singh Harpal 
Published: January 2009

AbstractRadiation grafting of acrylic acid onto poly(ethylene terephthalate) (PET) knittings was investigated by preirradiation technique. The influence of the grafting conditions, such as reaction time, ferrous sulfate concentration, preirradiation dose, organic additives, monomer concentration, and reaction temperature on the degree of grafting was investigated. Precise control over the degree of grafting was achieved by proper selection of the reaction conditions. The organic solvents such as methanol, acetone, isopropanol, THF, and MEK when used as sole medium do not allow the grafting to proceed, probably due to the inhibitory action. However, reasonable grafting proceeded when a mixture of water and organic solvent was used. Attenuated total reflectance‐FTIR spectroscopy analysis of the grafted knittings confirmed the existence of carboxylic acid groups in the knittings. The surface morphology, as studied by scanning electron microscopy (SEM), was significantly influenced by the addition of organic solvents in the reaction medium. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Cyclodextrin‐anionic polysaccharide hydrogels: Synthesis, characterization, and interaction with some organic molecules (water pollutants, drugs, proteins)
Authors: Mocanu G. , Mihai D. , LeCerf D. , Picton L. , Moscovici M. 
Published: January 2009

AbstractHydrogel microparticles have been prepared through cocrosslinking of cyclodextrin and of anionic carboxymethyl or sulfopropyl pullulan with a new bifunctional reagent: 3‐(glycidoxypropyl)trimethoxysilane. This reagent forms crosslinking both through grafting with the epoxy end on the OH polysaccharide and through hydrolysis and condensation of the methoxy silane groups from the other end. Samples of cyclodextrin/anionic polysaccharides with various amounts of crosslinking agent were prepared. Characterization of the hydrogel microparticles considered the water swelling behavior, porosity measurements, retention of biologically active substances, which can occur by their inclusion in cyclodextrin inner cavities and in the pores of hydrogels, as well as through the electrostatic forces toward anionic polyelectrolyte charges. Their improved retention of various organic molecules as water pollutants, drugs, enzymes, recommend them as chromatographic supports, supports for the separation/immobilization of enzymes or for controlled release systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Form‐fill‐seal methodology for controlled encapsulation of small silver particles in hyperbranched polyglycidol
Authors: Ding Xiangyu , Liu Hewen , Shi Wenfang , Skrifvars Mikael 
Published: January 2009

AbstractProduction of polar hyperbranched polymers and encapsulation of small particles in the hyperbranched polymers is like “forming” pouches and then “filling” these pouches. Modification of the end‐groups of the hyperbranched polymers with relative apolar groups is like “sealing” the pouches. In this article, we demonstrated that two methods depending on changed sequences, i.e., Form‐Fill‐Seal and Form‐Seal‐Fill methods resulted in different sized small particles with size‐depended properties. By using these approaches, small metal nano‐particles can be encapsulated inside polar microzones of dendritic‐star polymers taking advantage of the difference in partition coefficients instead of strong interactions between the dendritic polymers and ions. We used the methodology to produce small silver particles encapsulated in hyperbranched polyglycidol (HPG). The HPG was synthesized via anionic ring‐opening multibranching polymerization of glycidol. The “sealing” process was fulfilled by polymerization of ε‐caprolactone initiated from the end groups of HPG. In the Form‐Fill‐Seal approach, Ag+ was filled inside HPG, and then was sealed before reduction to Ag; whereas the “pouch” of HPG was sealed at first, and then Ag+ was filled inside HPG by diffusion in the Form‐Seal‐Fill approach. Mainly nanometer‐sized silver particles were formed by the Form‐Fill‐Seal approach, whereas silver clusters of several atoms were formed in the Form‐Seal‐Fill approach. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis, characterization, conductivity, band gap, and kinetic of thermal degradation of poly‐4‐[(2‐mercaptophenyl) imino methyl] phenol
Authors: Kaya İsmet , Baycan Fatma , Doğan Fatih 
Published: January 2009

AbstractThe oxidative polycondensation reaction conditions of 4‐[(2‐mercaptophenyl) imino methyl] phenol (2‐MPIMP) were studied in an aqueous acidic medium between 40 and 90°C by using oxidants such as air, H2O2, and NaOCl. The structures of the synthesized monomer and polymer were confirmed by FTIR, 1H NMR, 13C NMR, and elemental analysis. The characterization was made by TGA‐DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly‐4‐[(2‐mercaptophenyl) imino methyl]phenol (P‐2‐MPIMP) was found to be 92% for NaOCl oxidant, 84% for H2O2 oxidant 54% for air oxidant. According to the SEC analysis, the number‐average molecular weight (Mn), weight‐average molecular weight (Mw), and polydispersity index values of P‐2‐MPIMP were found to be 1700 g mol−1, 1900 g mol−1, and 1.118, using H2O2; 3100 g mol−1, 3400 g mol−1, and 1.097, using air; and 6750 g mol−1, 6900 g mol−1, and 1.022, using NaOCl, respectively. According to TG analysis, the weight losses of 2‐MPIMP and P‐2‐MPIMP were found to be 95.93% and 76.41% at 1000°C, respectively. P‐2‐MPIMP showed higher stability against thermal decomposition. Also, electrical conductivity of the P‐2‐MPIMP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, and the electrochemical energy gaps (E′g) of 2‐MPIMP and P‐2‐MPIMP were found to be −6.13, −6.09; −2.65, −2.67; and 3.48, 3.42 eV, respectively. Kinetic and thermodynamic parameters of these compounds investigated by MacCallum‐Tanner and van Krevelen methods. The values of the apparent activation energies of thermal decomposition (Ea), the reaction order (n), pre‐exponential factor (A), the entropy change (ΔS*), enthalpy change (ΔH*), and free energy change (ΔG*) were calculated from the TGA curves of compounds. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The frequency spectrum of finite samples from the intermittent silence process
Authors: Ferrer‐i‐Cancho Ramon , Gavaldà Ricard 
Published: January 2009

AbstractIt has been argued that the actual distribution of word frequencies could be reproduced or explained by generating a random sequence of letters and spaces according to the so‐called intermittent silence process. The same kind of process could reproduce or explain the counts of other kinds of units from a wide range of disciplines. Taking the linguistic metaphor, we focus on the frequency spectrum, i.e., the number of words with a certain frequency, and the vocabulary size, i.e., the number of different words of text generated by an intermittent silence process. We derive and explain how to calculate accurately and efficiently the expected frequency spectrum and the expected vocabulary size as a function of the text size.
Secondary flow mixing due to biofilm growth in capillaries of varying dimensions
Authors: Hornemann Jennifer A. , Codd Sarah L. , Fell Robert J. , Stewart Philip S. , Seymour Joseph D. 
Published: January 2009

AbstractUsing a magnetic resonance microscopy (MRM) technique, velocity perturbations due to biofouling in capillaries were detected in 3D velocity maps. The velocity images in each of the three square capillary sizes (2, 0.9, and 0.5 mm i.d.) tested indicate secondary flow in both the x‐ and y‐directions for the biofouled capillaries. Similar flow maps generated in a clean square capillary show only an axial component. Investigation of these secondary flows and their geometric and dynamic similarity is the focus of this study. The results showed significant secondary flows present in the 0.9 mm i.d. capillary, on the scale of 20% of the bulk fluid flow. Since this is the “standard 1 mm” size capillary used in confocal microscopy laboratory bioreactors to investigate biofilm properties, it is important to understand how these enhanced flows impact bioreactor transport. Biotechnol. Bioeng. 2009;103: 353–360. © 2009 Wiley Periodicals, Inc.
Randomized clinical trial of visualization versus neuromonitoring of recurrent laryngeal nerves during thyroidectomy
Authors: Barczyński M , Konturek A , Cichoń S 
Published: January 2009

Abstract

Background
The aim of this study was to test the hypothesis that identification of the recurrent laryngeal nerve (RLN) during thyroid surgery reduces injury, and that intraoperative nerve monitoring may be of additional benefit.

Methods
One thousand consenting patients scheduled to have bilateral thyroid surgery were randomized to standard protection or additional nerve monitoring. The primary outcome measure was prevalence of RLN injury.

Results
Of 1000 nerves at risk in each group, transient and permanent RLN injuries were found respectively in 38 and 12 nerves without RLN monitoring (P = 0·011) and 19 and eight nerves with RLN monitoring (P = 0·368). The prevalence of transient RLN paresis was lower in patients who had RLN monitoring by 2·9 per cent in high-risk patients (P = 0·011) and 0·9 per cent in low-risk patients (P = 0·249). The negative and positive predictive values of RLN monitoring in predicting postoperative vocal cord function were 98·9 and 37·8 per cent respectively.

Conclusion
Nerve monitoring decreased the incidence of transient but not permanent RLN paresis compared with visualization alone, particularly in high-risk patients. Registration number: NCT00661024 (http://www.clinicaltrials.gov).
Specific Labeling of Peptidoglycan Precursors as a Tool for Bacterial Cell Wall Studies
Authors: van Dam Vincent , Olrichs Nick , Breukink Eefjan 
Published: January 2009

AbstractWall chart: The predominant component of the bacterial cell wall, peptidoglycan, consists of long alternating stretches of aminosugar subunits interlinked in a large three‐dimensional network and is formed from precursors through several cytosolic and membrane‐bound steps. The high tolerance of the cell wall synthesis machinery allows for the use of labeled precursor derivatives to study diverse aspects of bacterial cell wall synthesis and interaction with antibiotics.magnified imageBecause of its importance for bacterial cell survival, the bacterial cell wall is an attractive target for new antibiotics in a time of great demand for new antibiotic compounds. Therefore, more knowledge about the diverse processes related to bacterial cell wall synthesis is needed. The cell wall is located on the exterior of the cell and consists mainly of peptidoglycan, a large macromolecule built up from a three‐dimensional network of aminosugar strands interlinked with peptide bridges. The subunits of peptidoglycan are synthesized inside the cell before they are transported to the exterior in order to be incorporated into the growing peptidoglycan. The high flexibility of the cell wall synthesis machinery towards unnatural derivatives of these subunits enables research on the bacterial cell wall using labeled compounds. This review highlights the high potential of labeled cell wall precursors in various areas of cell wall research. Labeled precursors can be used in investigating direct cell wall–antibiotic interactions and in cell wall synthesis and localization studies. Moreover, these compounds can provide a powerful tool in the elucidation of the cell wall proteome, the “wallosome,” and thus, might provide new targets for antibiotics.
The Structure of (SCN)x: A Study Using Molecular and Solid‐State Density Functional Theory Calculations
Authors: Früchtl Herbert A. , van Mourik Tanja , Pickard Chris J. , Woollins J. Derek 
Published: January 2009

AbstractA riddle solved! Despite its simple formula, the structure of the (SCN)x polymer has remained elusive since its first synthesis in 1929. From energetics as well as NMR chemical shifts, based on DFT calculations, we have strong evidence that it is indeed a tangle of linear chains, made up from N‐linked S2C2N five‐membered rings.magnified imageMolecular fragments and crystal structures based on proposed structures for polythiocyanogen were studied by using molecular and solid‐state electronic structure calculations at the density functional theory level. The energetics and chemical shifts from both types of calculations indicate that a planar N‐linked chain consisting of 1,2,4‐dithiazole five‐membered rings with adjacent rings pointing in opposite directions is the most likely local structure of the (SCN)x polymer.
Furazan‐Functionalized Tetrazolate‐Based Salts: A New Family of Insensitive Energetic Materials
Authors: Wang Ruihu , Guo Yong , Zeng Zhuo , Twamley Brendan , Shreeve Jean'ne M. 
Published: January 2009

AbstractInsensitive energetic salts: A series of furazan‐functionalized tetrazolate‐based energetic salts (see figure) were synthesized and characterized. All of the salts exhibit excellent thermal stabilities and high positive heats of formation.magnified imageFurazan‐functionalized tetrazolate‐based energetic salts (1–13) were prepared by direct treatment of neutral 4‐amino‐3‐(5‐tetrazole)furazan and a Lewis base or by simple metathesis reactions of its barium salt formed in situ with the corresponding sulfate salts in aqueous solution. Key physical properties, such as melting point, thermal stability, density, hypergolicity, and sensitivity to shock, were measured. The relationship between their structures and these properties was determined. Most of salts exhibit better thermal stability than their 5‐nitrotetrazolate and 5‐nitraminotetrazolate analogues as well as other furazan‐based salts. The structures of representative aminoguanidinium (4), carbonic hydrazylhydrazidinium (9), and 1,4‐dimethyl‐5‐aminotetrazolium salts (13) were further confirmed by single‐crystal X‐ray analysis. Their densities, heats of formation, detonation pressures and velocities, and specific impulses were calculated. All of the salts possess high positive heats of formation. The effect of the furazan ring on these physicochemical properties was examined and discussed.
Physikalische Experimente und numerische Methoden im Explosionsschutz
Authors: Sippel M. , Wörsdörfer K. , Barth U. 
Published: January 2009

AbstractDie explosionsdruckstoßfeste Eigenschaft von Geräten und Anlagen beschreibt die Eigenschaft, einem Überdruck aufgrund eines Explosionsereignisses zu widerstehen, wobei eine lokale, dauerhafte Verformungen toleriert, ein Aufreißen der Struktur mit nachfolgendem Flammenaustritt in die Umgebung jedoch nicht toleriert wird. Oftmals bedeutet die Prüfung explosionsdruckstoßfester Geräte eine experimentelle Prüfung mittels des kompletten Gerätes. Mesit handelt es sich um eine zeit‐ und kostenintensive try‐and‐error‐Methode, bis eine geeignete konstruktive Ausführung gefunden wird. Eine sinnvolle Ergänzung für zukünftige Prüfungen von explosionsfesten Geräten wird in numerischen Methoden gesehen. In diesem Zusammenhang bietet sich neben der Nutzung von Finite Elemente Modellen (FEM) zur Berechnung von Bauteilverformungen ebenfalls die Ergänzung dieser Modelle durch Software zur Strömungssimulation an, die über entsprechende Parametrisierung explosionstypische Lastrandbedingungen generiert.
Druckstöße in Rohrleitungen: Störungsszenarien, Sicherheitsbetrachtungen und Gegenmaßnahmen
Authors: Hahn M. 
Published: January 2009

AbstractIn durchströmten Rohrleitungen können transiente Strömungsvorgänge, z. B. schnelle Änderungen des Durchflusses oder dynamische inhomogene Zweiphasenströmungen, Druckstöße bewirken, die zu Schädigungen von Rohrleitungen bis hin zum Versagen mit Stofffreisetzung führen können. Für mögliche Störungsszenarien werden systematische Sicherheitsbetrachtungen dargestellt, um geeignete Gegenmaßnahmen zur Gewährleistung der Sicherheit und Verfügbarkeit von Rohrleitungen abzuleiten.
Hat der Klimawandel Auswirkungen auf die Anlagensicherheit?
Authors: Stock M. 
Published: January 2009

AbstractUmgebungsbedingte Gefahrenquellen für Anlagen wie Stürme, Hochwasser, Waldbrände und Gewitter hängen von Klimaparametern ab und zeigen teilweise erhöhte Risiken im Klimawandel. Für diese Ereignisse beobachtet man seit etwa 1970 eine Zunahme der Häufigkeit sowie teilweise auch der Parameter, die das Schadenspotenzial erhöhen. Zusammenhänge mit dem bereits laufenden Klimawandel deuten sich an, sind aber noch relativ unsicher. Für einige Prozesse, wie tropische Wirbelstürme und lokale Gewitterereignisse ist dies ansatzweise quantifizierbar, für andere Risiken lässt sich qualitativ der Bezug zur Temperaturänderung aufzeigen. Die aufgeführten Temperaturabhängigkeiten weisen eine exponentielle Abhängigkeiten oder solche mit hoher Potenz auf, sodass bei stark zunehmender globaler Erwärmung oberhalb von 2 °C neue Qualitäten erhöhter Risiken nicht auszuschließen sind.