bluuebunny/crossref_metadata_2025 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

Verträgliche Katalyse: Die Kreuzkupplung von nichtaktivierten und funktionalisierten Alkylhalogeniden mit Alkyl‐Grignard‐Reagentien wird durch den diskreten Nickel(II)‐Komplex 1 katalysiert. Die Umsetzung toleriert wichtige funktionelle Gruppen, die mit Grignard‐Reagentien in Kreuzkupplungen oftmals unverträglich sind.

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QM/MM Methods for Biomolecular Systems
Authors: Senn Hans Martin , Thiel Walter
Published: January 2009

Two are better than one: Quantum mechanics/molecular mechanics (QM/MM) methods are the state‐of‐the‐art computational technique for treating reactive and other “electronic” processes in biomolecular systems. This Review presents the general methodological aspects of the QM/MM approach, its use within optimization and simulation techniques, and its areas of application, always with a biomolecular focus.

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Combined quantum‐mechanics/molecular‐mechanics (QM/MM) approaches have become the method of choice for modeling reactions in biomolecular systems. Quantum‐mechanical (QM) methods are required for describing chemical reactions and other electronic processes, such as charge transfer or electronic excitation. However, QM methods are restricted to systems of up to a few hundred atoms. However, the size and conformational complexity of biopolymers calls for methods capable of treating up to several 100 000 atoms and allowing for simulations over time scales of tens of nanoseconds. This is achieved by highly efficient, force‐field‐based molecular mechanics (MM) methods. Thus to model large biomolecules the logical approach is to combine the two techniques and to use a QM method for the chemically active region (e.g., substrates and co‐factors in an enzymatic reaction) and an MM treatment for the surroundings (e.g., protein and solvent). The resulting schemes are commonly referred to as combined or hybrid QM/MM methods. They enable the modeling of reactive biomolecular systems at a reasonable computational effort while providing the necessary accuracy.
New Principles for Glycoside‐Bond Formation
Authors: Zhu Xiangming , Schmidt Richard R.
Published: January 2009

Meeting the demand for sugars: The importance of oligosaccharides and glycoconjugates in biological systems has stimulated a need to access significant amounts of these compounds. Much effort has been devoted to the stereoselective generation of the key glycosidic bond, both between carbohydrate residues (see scheme) and to the aglycone. Various methodologies are now available for the efficient synthesis of structurally defined complex oligosaccharides and glycoconjugates.

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Increased understanding of the important roles that oligosaccharides and glycoconjugates play in biological processes has led to a demand for significant amounts of these materials for biological, medicinal, and pharmacological studies. Therefore, tremendous effort has been made to develop new procedures for the synthesis of glycosides, whereby the main focus is often the formation of the glycosidic bonds. Accordingly, quite a few review articles have been published over the past few years on glycoside synthesis; however, most are confined to either a specific type of glycoside or a specific strategy for glycoside synthesis. In this Review, new principles for the formation of glycoside bonds are discussed. Developments, mainly in the last ten years, that have led to significant advances in oligosaccharide and glycoconjugate synthesis have been compiled and are evaluated.
Semisynthesis of a Homogeneous Glycoprotein Enzyme: Ribonuclease C: Part 1
Authors: Piontek Christian , Ring Petra , Harjes Olaf , Heinlein Christian , Mezzato Stefano , Lombana Nelson , Pöhner Claudia , Püttner Markus , Varón Silva Daniel , Martin Andreas , Schmid Franz Xaver , Unverzagt Carlo
Published: January 2009

Seven in one blow: The efficient formation of mixed disulfides on the thiol‐rich fusion proteinAfollowed by subsequent intein cleavage gave the fragmentBwith all seven cysteines protected against oxidation. The native chemical ligation ofBwith synthetic glycopeptide thioesters provides glycoproteins.

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An Ugi Reaction in the Total Synthesis of (−)‐Dysibetaine
Authors: Isaacson Jerry , Kobayashi Yoshihisa
Published: January 2009

(−)‐Dysibetaine has been synthesized in 11 steps from readily available L‐malic acid (see scheme). The key step is a unique Ugi 4‐center‐3‐component cyclization reaction, where an ester group acts as the carboxylic acid component. The use of 1,1,1,3,3,3‐hexamethyldisilazane as an ammonia equivalent and a specially designed isocyanide leads to an expeditious synthesis.

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Patterned Monolayers of Neutral and Charged Functionalized Manganese Arene Complexes on a Highly Ordered Pyrolytic Graphite Surface
Authors: Kim Sang Bok , Pike Robert D. , D'Acchioli Jason S. , Walder Brennan J. , Carpenter Gene B. , Sweigart Dwight A.
Published: January 2009

Complex patterns: The arene manganese tricarbonyl complexes [Mn(η5‐2,5‐didodecoxy‐1,4‐semiquinone)(CO)3] and [Mn(η6‐1,4‐dioctyloxybenzene)(CO)3] BF4 form patterned monolayers on the surface of highly ordered pyrolytic graphite (HOPG), as a result of hydrogen‐bonding, hydrophobic, and electrostatic interactions, leading to an ordered 2D array of manganese atoms or ions.

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Air‐Stable {(C5H5)Co} Catalysts for [2+2+2] Cycloadditions
Authors: Geny Anaïs , Agenet Nicolas , Iannazzo Laura , Malacria Max , Aubert Corinne , Gandon Vincent
Published: January 2009

Cobalt cyclopentadienyl complexes incorporating a fumarate and a CO ligand (see picture) efficiently catalyze inter‐ and intramolecular [2+2+2] cycloadditions of alkynes, nitriles, and/or alkenes to give benzenes, pyridines, or 1,3‐cyclohexadienes. Unlike catalysts such as [CpCo(CO)2] or [CpCo(C2H4)2] (Cp=C5H5), they are air‐stable, easy to handle, compatible with microwave conditions, and do not necessarily require irradiation to be active.

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

Reacting 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.

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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

In 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

This 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

Five 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

Radiation 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

Hydrogel 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

Production 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

The 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

It 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

Using 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

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

Wall 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.

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Because 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

A 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.

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Molecular 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

Insensitive 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.

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Furazan‐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

Die 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

In 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

Umgebungsbedingte 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.
Prognostic model to predict outcomes in nonsmall cell lung cancer patients treated with gefitinib as a salvage treatment
Authors: Jae Park Min , Lee Jeeyun , Hong Jung Yong , Choi Moon Ki , Yi Joon Ho , Lee Su Jin , Oh Suk Joong , Ahn Jin Seok , Park Keunchil , Ahn Myung Ju
Published: January 2009

BACKGROUND:

A prognostic model based on clinical parameters for nonsmall cell lung cancer (NSCLC) patients treated with gefitinib (250 mg/day) as a salvage therapy was devised.

METHODS:

Clinical data regarding a total of 316 metastatic or recurrent NSCLC patients who were treated with gefitinib were analyzed.

RESULTS:

Poor prognostic factors for overall survival (OS) by multivariate analysis were an Eastern Cooperative Oncology Group (ECOG) performance status of 2 to 3 (hazards ratio [HR] of 2.07; 95% confidence interval [CI], 1.57‐2.73 [P < .001]), the presence of intra‐abdominal metastasis (HR of 1.76; 95% CI, 1.33‐2.34 [P < .001]), elevated serum alkaline phosphatase (HR of 1.50; 95% CI, 1.13‐2.00 [P = .005]), time interval from diagnosis to gefitinib therapy of ≤12 months (HR of 1.48; 95% CI, 1.12‐1.95 [P = .005]), low serum albumin (HR of 1.45; 95% CI, 1.09‐1.92 [P = .009]), progression‐free interval for previous chemotherapy of ≤12 weeks (HR of 1.40; 95% CI, 1.0‐1.84 [P = .015]), white blood cell >10,000/μL (HR of 1.38; 95% CI, 1.02‐1.85 [P = .032]), and ever‐smoker (HR of 1.33; 95% CI, 1.02‐1.75 [P = .033]). Of the 272 patients applicable to this prognostic model, 41 patients (15%) were categorized as a good prognosis group (0‐1 risk factors), 100 patients (37%) as an intermediate prognosis group (2‐3 risk factors), 81 patients (30%) as a poor prognosis group (4‐5 risk factors), and 50 patients (16%) as a very poor prognosis group (≥6 risk factors). The median OS from the time of gefitinib treatment for the good, intermediate, poor, and very poor prognosis groups were 18.0 months, 11.2 months, 4.0 months, and 1.3 months, respectively (P < .001).

CONCLUSIONS:

This prognostic model based on easily available clinical variables would be useful to identify patients who might derive more benefit from gefitinib treatment and to make decisions in clinical practice. Cancer 2009. © 2009 American Cancer Society.
Stochastic modeling of columnar dendritic grain growth in weld pool of Al‐Cu alloy
Authors: Zhan X. H. , Dong Z. B. , Wei Y. H. , Tian N.
Published: January 2009

A multi‐scale model is used to simulate columnar dendritic growth in TIG (tungsten inert‐gas) weld molten pool of Al‐Cu alloy. The grain morphologies at the edge of the weld pool are studied. The simulated results indicate that the average primary dendrite spacing changes during the solidification process in the weld pool because of the complicated thermal field, solute diffusion field and competitive growth. And it is shown that the secondary dendrite arms grow insufficiently in the space between dendrite trunks if the primary dendrite spacing is small. And the phenomenon has been explained by analyzing the influence of the solute accumulation on the constitutional undercooling and undercooling gradient when there are two different opposite solute diffusion fields. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inorganic and organic templates‐assisted solvothermal synthesis of trigonal selenium microrods
Authors: Ma Jianmin , Sun Chuansheng , Lian Jiabiao , Zheng Wenjun
Published: January 2009

A facile and environment‐friendly solvothermal method has been developed for the controlled growth of nano‐ and micro‐structured trigonal selenium (t‐Se) by using green templates. And, the morphology of trigonal selenium can be tuned by using different kinds of templates. The as‐obtained products were characterized by X‐ray powder diffraction (XRD) and scanning electron microscope (SEM). Furthermore, the formation mechanism of trigonal selenium nano‐ and microcrystals was rationally suggested. This method will open a new avenue to synthesize other functional inorganic nano‐ and microcrystals. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of metastable zone width of ammonium oxalate aqueous solutions
Authors: Sangwal K. , Wójcik K.
Published: January 2009

The metastable zone width of pure ammonium oxalate aqueous solutions, as represented by maximum supercooling ΔTmax, is investigated as functions of cooling rate R and saturation temperature T0 by the polythermal method. The experimental results are discussed by using two recently advanced approaches: (1) self‐consistent Nývlt‐like approach based on a power‐law relationship between nucleation rate J and maximum supersaturation lnSmax, and (2) a novel approach based on the relationship between J and lnSmax described by the classical three‐dimensional nucleation theory. Analysis of the experimental data revealed that both approaches describe the experimental data on metastable zone width by the polythermal method reliably and provide useful information about the physical processes and parameters involved in nucleation kinetics. The values of various physical quantities predicted by both of these approaches are reasonable for a fairly‐soluble compound. A careful examination of the data on ΔTmax as a function of T0 obtained by polythermal method and from density measurements showed that ΔTmax has a slight tendency to decrease with increasing saturation temperature T0. The values of lnSmax at saturation temperature 303 K suggest that the metastable zone width of ammonium oxalate aqueous solutions is determined by primary nucleation in the polythermal method and by secondary nucleation during density measurements. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of annealing on structural, electrical and optical properties of AgGa(Se0.5S0.5)2 thin films deposited by using sintered stoichometric powder
Authors: Karaagac H. , Parlak M.
Published: January 2009

The structural, electrical and optical properties of AgGa(Se0.5S0.5 )2 thin films deposited by using the thermal evaporation method have been investigated as a function of annealing in the temperature range of 450–600 °C. X‐ray diffraction (XRD) analysis showed that the structural transformation from amorphous to polycrystalline structure started at 450 oC with mixed binary phases of Ga2Se3, Ga2S3, ternary phase of AgGaS2 and single phase of S. The compositional analysis with the energy dispersive X‐ray analysis (EDXA) revealed that the as‐grown film has different elemental composition with the percentage values of Ag, Ga, Se and S being 5.58, 27.76, 13.84 and 52.82 % than the evaporation source powder, and the detailed information about the stoichometry and the segregation mechanisms of the constituent elements in the structure have been obtained. The optical band gap values as a function of annealing temperature were calculated as 2.68, 2.85, 2.82, 2.83, and 2.81 eV for as‐grown, annealed at 450, 500, 550, and 600 °C samples, respectively. It was determined that these changes in the band gap are related with the structural changes with annealing. The temperature dependent conductivity measurements were carried out in the temperature range of 250‐430 K for all samples. The room temperature resistivity value of as‐grown film was found to be 0.7x108 (Ω‐cm) and reduced to 0.9x107 (Ω‐cm) following to the annealing. From the variation of electrical conductivity as a function of the ambient temperature, the activation energies at specific temperature intervals for each sample were evaluated. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of a two‐dimensional porous framework based on symmetrical organic ligand and linking metal ion
Authors: Wu Jian
Published: January 2009

Reaction of a pyridinecarboxylate ligand with copper salt affords a novel coordinative polymer [Cu(bpdc)(H2O)2·2H2O]n (bpdc=.2,2'‐bipyridyl‐3,3'‐dicarboxylate). It has 2‐D (4,4) layered network extended by the tetradentate bridging ligands, further interestingly, the coordinative and lattice water molecules acting as donor and acceptor linking the uncoordinated carboxylate groups into a inorganic (6,3) network. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microscopic studies on imperfections in selected YAB single crystals
Authors: Malicskó L. , Pogány L. , Tóth A. L. , Horváth V. , Beregi E.
Published: January 2009

The as‐grown surface and inner structures of undoped and Nd3+‐, Cr3+‐, V3+‐, Ce3+‐, Er3+ and Yb3+ – and (Er3+ + Yb3+) – doped yttrium aluminum borate (YAB) single crystals grown from (K2Mo3O10 + B2O3) flux by spontaneous crystallization or top seeded solution growth (TSSG) technique, were investigated using optical and scanning electron microscopic and analytic chemical methods. Fine and rough growth hillocks of dislocational origin, growth layers, traces of inner planar defects and foreign phase crystalline debris were found and analyzed on the as‐grown faces of crystals. Irregular grains and regular block structures and foreign phase inclusions were observed and studied in the interior of the crystals. The chemical compositions measured by energy dispersive X‐ray spectrometry on perfect and imperfect micro regions are compared with those obtained by flame atomic absorption spectrometry on bulk crystals. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anode Catalysts for Direct Ethanol Fuel Cells Utilizing Directly Solar Light Illumination
Authors: Chu Daobao , Wang Shuxi , Zheng Peng , Wang Jian , Zha Longwu , Hou Yuanyuan , He Jianguo , Xiao Ying , Lin Huashui , Tian Zhaowu
Published: January 2009

Shine a light: A PtNiRu/TiO2anode catalyst for direct ethanol fuel cells shows photocatalytic activity. The peak current density for ethanol oxidation under solar light illumination is 2–3 times greater than that in the absence of solar light. Ethanol is oxidized by light‐generated holes, and the electrons are collected by the TiO2support to generate the oxidation current.

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Novel PtNiRu/TiO2anode catalysts for direct ethanol fuel cells (DEFCs) were prepared from PtNiRu nanoparticles (1:1:1 atomic ratios) and a nanoporous TiO2film by a sol‐gel and electrodeposition method. The performances of the catalysts for ethanol oxidation were investigated by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. The results indicate a remarkable enhancement of activity for ethanol oxidation under solar light illumination. Under solar light illumination, the generated oxidation peak current density is 24.6 mA cm−2, which is about 2.5 times higher than that observed without solar light (9.9 mA cm−2). The high catalytic activity of the PtNiRu/TiO2complex catalyst for the electrooxidation of ethanol may be attributed to the modified metal/nanoporous TiO2film, and the enhanced electrooxidation of ethanol under solar light may be due to the photogeneration of holes in the modified nanoporous TiO2film.
Palladium‐Catalysed Direct 3‐ or 4‐Arylation of 2,5‐Disubstituted Pyrrole Derivatives: An Economically and Environmentally Attractive Procedure
Authors: Fall Yacoub , Doucet Henri , Santelli Maurice
Published: January 2009

Straight to the point: The direct 3‐ or 4‐arylation of pyrrole derivatives through CH bond activation proceeds in moderate to good yields using Pd(OAc)2 as catalyst. In contrast to classical coupling procedures, the preparation of an organometallic derivative is not required and the major by‐products are AcOH/KBr instead of metallic salts.

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Epithelial inclusion cyst arising in an intramammary lymph node: Case report with cytologic findings
Authors: Nakaguro Masato , Suzuki Yasuhiko , Ichihara Shu , Kobayashi Tadao K. , Ono Kenzo
Published: January 2009

The occurrence of epithelial inclusion cysts (EIC) in axillary lymph nodes is a rare but well recognized entity, arising either from direct implantation or from embryonal rests. Theoretically, EIC can occur in intramammary lymph nodes, but there has been only one prior report of such a lesion. Here, we describe a case of an EIC arising in an intramammary lymph node of a 37‐year‐old woman. This report focuses on the FNA cytologic features of this lesion and its differential diagnoses. On FNA, the EIC arising in an intramammary lymph node was characterized by mature lymphocytes, squamous epithelial cells, and keratinizing material. The presence of squamous cells can lead to the erroneous diagnosis of more common breast lesions, such as squamous cell carcinoma or metaplastic carcinoma. Contrary to these more sinister diagnoses, EIC arising in an intramammary lymph node is a benign condition. As this rare lesion sometimes mimics a neoplasm both clinically and radiographically, awareness of this entity is important to prevent over treatment. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.
Electroless Plating of Nickel Nanoparticles on CdS Nanowires
Authors: Wang Le , Liu Xinzheng , Yang Min , Fan Yingju , Zhan Jinhua
Published: January 2009

Preparation of 1D CdS‐Ni semiconductor‐magnetic nanocomposites was achieved by means of electroless plating of nickel nanoparticles on CdS nanowires. Preformed CdS nanowires with a diameter of ca. 45 nm, a length up to several tens of μm were magnetically functionalised by the hydrazine‐induced reduction of nickel chloride in ethylene glycol at 140 °C. It was found that nickel nanoparticles with a diameter of ca. 80 nm anchored on the nanowires without any surface pretreatment. Furthermore, a conversion process was detected and confirmed, something which is favourable for the nonepitaxial growth of Ni nanoparticles on CdS nanowires. The products prepared thereof were characterised in detail by XRD, TEM, HR‐TEM and EDS techniques. Magnetic property measurements show that the nanocomposites display ferromagnetic properties at room temperature.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Corundum‐Type In2O3 Urchin‐Like Nanostructures: Synthesis Derived from Orthorhombic InOOH and Application in Photocatalysis
Authors: Chen Li‐Yong , Liang Yi , Zhang Zu‐De
Published: January 2009

A facile route was applied to synthesize indium oxyhydroxide (InOOH) with urchin‐like nanostructures through polymer‐assisted hydrolysis of the In3+ cation in water/ethanol mixed solvent. The uniform InOOH urchin‐like nanostructures are composed of nanorods with a diameter of several nanometers and a length up to 100 nm. Investigation of the effects of various reaction parameters reveals that poly(ethylene glycol)‐1000 (PEG‐1000) and reaction temperature have significant influences on the morphology of the as‐prepared products. The formation of InOOH urchin‐like nanostructures can be due to anisotropic structure and PEG‐1000 selective adsorption. By annealing the preobtained InOOH precursor at 500 °C under ambient pressure, metastable hexagonal indium oxide (H‐In2O3) urchin‐like nanostructures, inheriting the morphology of its precursor in the transformation process, were obtained. The photocatalytic activity of as‐prepared H‐In2O3 was evaluated by photodegradation of rhodamine B (RhB) dye under ultraviolet (UV) light illumination. The stability of the photocatalytic performance of H‐In2O3 urchin‐like nanostructures was investigated by circulating run tests in the photodegradation of RhB.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
One‐Step Synthesis and Characterization of SiC, Mo2C, and WC Nanostructures
Authors: Pol Vilas G. , Pol Swati V. , Gedanken Aharon
Published: January 2009

This review describes a novel approach for the syntheses of various carbides of silicon, tungsten, and molybdenum at a relatively low temperature by using the RAPET (Reactions under Autogenic Pressure at Elevated Temperature) process. The solvent‐, template‐free and straightforward RAPET process was used to synthesize a range of new carbide materials with or without the use of catalysts. The thermolysis of precursor(s) in a closed reactor without using additional reducing gases and the characterization of the obtained high‐surface‐area β‐SiC nanorods, micro‐ or nanosized Mo2C spheres and WC nanotubes are the key issues described. The capability of the RAPET process to fabricate nanoparticles, nanorods, and nanotubes of different carbides in a single‐step reaction is also demonstrated. By taking advantage of the achieved highest surface area (563 m2/g) of SiC, it was possible to store approximately 2 wt.‐% of H2 at room temperature and 6 MPa.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Extended Members of the Layered Rare‐Earth Hydroxide Family, RE2(OH)5NO3·nH2O (RE = Sm, Eu, and Gd): Synthesis and Anion‐Exchange Behavior
Authors: Lee Kyung‐Hee , Byeon Song‐Ho
Published: January 2009

Three new layered rare‐earth hydroxides (LRHs), RE(OH)2.5(NO3)0.5·xH2O (RE = Gd, Eu, and Sm), have been prepared by a hydrothermal reaction. These materials correspond to the extended members of the RE2(OH)5NO3·nH2O (RE = the rare‐earth series) family. Although it has been suggested that the LRH structure seems to be kinetically favored by yttrium or (the second half of) the small rare‐earth ions, an appropriate control of pH conditions for the hydrothermal reaction could extend this family to the larger rare‐earth ions in the present study. The ion‐exchange reactions between NO3– and diverse organic anions (a series of organic carboxylates, 1‐alkanesulfonates, and alkylsulfates) were successfully carried out in the gallery of layered rare‐earth hydroxides, RE2(OH)5NO3·nH2O (RE = Gd, Eu, and Sm). The FTIR spectra of the LRH hosts and some selected organic anion‐exchanged derivatives clearly revealed the absence of nitrate and the appearance of characteristic bands attributed to carboxylate and sulfonate groups after the exchange reactions. Despite a large expansion of interlayer spacing, the layered gadolinium hydroxide and the long alkyl chain anion‐exchanged derivative showed a similar paramagnetic behavior.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Scandium‐Catalyzed Polymerization of CH3(CH2)nCH=CH2 (n = 0–4): Remarkable Activity and Tacticity Control
Authors: Ward Benjamin D. , Lukešová Lenka , Wadepohl Hubert , Bellemin‐Laponnaz Stéphane , Gade Lutz H.
Published: January 2009

The C3‐symmetric trisoxazoline‐supported scandium complex [Sc(iPr‐trisox)(CH2SiMe3)3] (2) is highly active in the stereospecific polymerization of propene, 1‐butene, 1‐pentene, 1‐hexene and 1‐heptene, when activated with two equivalents of [Ph3C][B(C6F5)4]. The polymers thus produced were found to possess narrow molecular weight distributions and high levels of tacticity control (up to 99 % mmmm). Some insight into the nature of the active species was obtained by 1H, 13C and 29Si NMR experiments. In particular, the formation of two equivalents of Ph3CCH2SiMe3 at ambient temperature was observed alongside a C3‐symmetric scandium complex tentatively assigned as the dication [Sc(iPr‐trisox)(CH2SiMe3)]2+.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)