bluuebunny/crossref_metadata_2025_split huggingface dataset:
MRI‐guided cryotherapy
Authors: Morrison Paul R. , Silverman Stuart G. , Tuncali Kemal , Tatli Servet 
Published: January 2008

AbstractOver the last decade the focus of published research on MRI‐guided cryotherapy has switched from the study of experimental models to the clinical treatment of patients. The latter reports attest to the safety and feasibility of treating lesions in the liver, kidney, and other sites throughout the body. Further, the published images and initial results speak to the utility of MRI for the task of monitoring this specific procedure. This clinical utility is a realization of the promise of the earlier experimental work that showed the clarity with which interstitial ice is seen under MRI under various pulse sequence parameters. Early adopters have taken advantage of access to the patient that is provided by low and mid‐field open scanners; the near future will test the suitability of higher field systems. It has been critical that an FDA‐approved cryotherapy system and suitably thin probes were customized for the MRI environment a decade ago by which percutaneous cryotherapy could be performed. There is still work to be done to expand the role of percutaneous cryotherapy, to understand various tissue responses, and to optimize visualization of therapeutic isotherms. Also, long‐term outcomes need to be assessed. Overall, in a worldwide environment in which the practice of ablation is growing and an appreciation for such therapies is on the rise, the work of these recent years provides sound footing for the advances that lay ahead for clinical MRI‐guided cryotherapy. J. Magn. Reson. Imaging 2008;27:410–420. © 2008 Wiley‐Liss, Inc.
Characterization of archaeological bronze and evaluation of the benzotriazole efficiency in alkali medium
Authors: Hassairi H. , Bousselmi L. , Khosrof S. , Triki E. 
Published: January 2008

AbstractAn analytic study permits us to characterize the altered surface of an archaeological bronze coin and to determine the structure and the composition of the patina covering the whole surface of this artefact. This patina could be interpreted at first sight as a type I patina, with copper product deposits on it, with some punctual and enlarged localized type II corrosion.To achieve the purpose of this work, we investigate the behaviour of an archaeological bronze in the presence of benzotriazole (BTA) in alkali medium with the intention of getting a better passivity while favouring the formation of a polymeric film on the surface of the working electrode. The behaviour of the considered interface is investigated by electrochemical impedance spectroscopy, in the presence and absence of an oxide layer, according to the immersion time.At pH = 9, in the presence of 15 mmol/l of BTA, the optimum percentage of inhibition efficiency (IE%) is 67% obtained after 30 min of immersion. A pre‐polarization of the bronze working electrode is realized in order to accommodate the preservation technique used in museums and to improve the formation of the Cu(I)‐BTA polymeric film. The use of a pre‐polarized electrode for 30 min at −35 mV/SCE carries an enhancement of the protection versus the non‐polarized electrode. While comparing the result of our investigation with that obtained using the traditional preservation method, we can establish that using a concentration of BTA 15 times lower, important inhibitor efficiencies (%) of 92 and 97.4%, respectively, for 30 min and 96 h of immersion are reached.
Breakaway properties of film formed on copper and copper alloys in erosion–corrosion by mass transfer equation
Authors: Yabuki A. , Murakami M. 
Published: January 2008

AbstractErosion–corrosion tests on copper and three types of copper alloys in a 1 wt% solution of CuCl2 were carried out at various flow velocities using a jet‐in‐slit testing apparatus, which is capable of reproducing various hydrodynamic conditions. A damage profile of a specimen was developed using a surface roughness meter to evaluate locally occurring damage. The damage depth rate for copper, beryllium copper, and a 70/30 copper nickel alloy increased with increasing flow velocity, and suddenly increased at a certain velocity, which is called the breakaway velocity. The breakaway velocities at the central and disturbed part of a specimen were different for each sample, indicating that the hydrodynamic conditions of the flowing solution had an effect. The damage depth rate, calculated from the mass transfer equation, which involved mass transfer in the concentration diffusion layer and in the corrosion product film, could be fitted to the experimental data, suggesting that the mass transfer equation can be applied to the evaluation of erosion–corrosion damage. The corrosion product film was exponentially broken away at velocities higher than the breakaway velocity. The breakaway properties of the corrosion product film were confirmed to be different for each material, since the power of the exponential equation was different for each sample.
Atmospheric corrosion of galvanized steel and aluminium in marine and marine‐industrial environments of Saudi Arabia
Authors: Almarshad A. I. , Syed S. 
Published: January 2008

AbstractThree‐year exposure programme was carried out in Saudi Arabia at nine test stations with different climatic and pollution conditions. The aim of this study was to evaluate the joint effect of atmospheric pollutants (Cl− and SO2), relative humidity (RH) and temperature (T) on the atmospheric corrosion of galvanized steel (GS) and aluminium (Al). Corrosion rates of the two metals have been obtained by loss of weight after 1, 2 and 3 years exposure. The composition of the corrosion products formed on the specimens was identified by X‐ray diffraction analysis. A classification of the atmospheric corrosion aggressivity of the test sites based both on environmental data and corrosion rate measurements was made according to ISO 9223. In some regions, it can be found that corrosion rate values exceed those established by the ISO standard.
Poly(hydroxyethyl methacrylate)‐Based Macroporous Hydrogels with Disulfide Cross‐Linker
Authors: Andac M. , Plieva F. M. , Denizli A. , Galaev I. Yu. , Mattiasson B. 
Published: January 2008

AbstractBiodegradable supermacroporous PHEMA cryogels were produced by combining two crosslinkers, poly(ethylene glycol) diacrylate and a newly developed disulfide water soluble crosslinker, N,N′‐bis(methacryloyl)‐L‐cystine. The biodegradable PHEMA cryogels were prepared with gel fraction yields up to 70% and were characterized by highly interconnected pores of micrometer size and good mechanical stability. When subjected to reductive agents like DTT, the biodegradable PHEMA cryogels disintegrated into small pieces. The rate of disintegration was controlled by the crosslinking density in the cryogels and the DTT concentration.magnified image
The Effect of Nanofiller on the Thermomechanical Properties of Polyimide/Clay Nanocomposites
Authors: Mya Khine Yi , Wang Ke , Chen Ling , Lin Ting Ting , Pallathadka Pramoda K. , Pan Jisheng , He Chaobin 
Published: January 2008

AbstractThe interaction between PI and partially exfoliated clay nanofillers is investigated by studying the thermomechanical properties of the resulting nanocomposites by NMR, XPS, XRD, TEM, TGA, TMA, and DMA. XRD and TEM showed more exfoliated structure at ≤2.5 wt.‐% clay and a macrophase separation above 2.5 wt.‐% clay. Td and the storage modulus increased with increasing clay content. A decrease in CTE was observed for clay content ≤2.5 wt.‐% because of the good dispersion of the clay in the polymer and the reduced segmental motion of polymer matrix. NMR confirmed the quality of clay dispersion, and XPS exhibited that the interaction in PI/2.5 wt.‐% clay is much stronger than that in PI/5 wt.‐% clay.magnified image
Tuning the Photoluminescence of Silsesquioxanes with Short Substituted Urea Bridges
Authors: Gómez María L. , Fasce Diana P. , Williams Roberto J. J. , Previtali Carlos M. , Matějka Libor , Pleštil Josef , Brus Jiří 
Published: January 2008

AbstractThe polycondensation of a precursor synthesized by the reaction of 3‐(anilinepropyl)trimethoxysilane with 3‐(isocyanatopropyl)triethoxysilane led to a silsesquioxane bearing a substituted urea group in the short organic bridge. The self‐assembly of organic bridges, analyzed by SAXS and FTIR spectra, could be controlled by varying the conditions of the synthesis. Depending on the size of organic clusters, the silsesquioxane exhibited photoluminescence either in the green or red regions of the spectra, or an emission that could be tuned in the whole visible region by the excitation wavelength.magnified image
Encapsulation and Stabilization of Photo‐Sensitive Antioxidants by Using Polymer Microcapsules with Controlled Phase Heterogeneity
Authors: Koo Bo‐Mi , Jung Jae‐Eun , Han Joo‐Hyun , Kim Jin‐Woong , Han Sang‐Hoon , Chung Dong June , Suh Kyung‐Do 
Published: January 2008

AbstractWe describe a robust method for both encapsulating and stabilizing photo‐sensitive antioxidants in polymer microcapsules prepared by a water‐in‐oil‐in‐water double emulsification and evaporation technique, in which a volatile solvent from the oil layer consisting of poly(methyl methacrylate) and methylene chloride is gradually removed. Using poly(ethylene glycol) (PEG) in this study, we demonstrate that control over its molecular weight allows to tune the phase property of the capsule wall; introducing PEG with high molecular weight results in increased heterogeneity. The heterogeneity of the capsule walls displays an ability to effectively block sunlight, which is essential for improving the molecular stability of photo‐sensitive antioxidants. In this study, we experimentally confirm this by observing natural sunlight‐driven molecular decomposition of a model antioxidant, riboflavin‐5′‐phosphate, in poly (methyl methacrylate) microcapsules.magnified image
Untersuchung der Einflüsse von Substratrauheit und Spritzpartikelgröße auf die Haftung thermisch gespritzter Schichten
Authors: Bach Fr.‐W. , Möhwald K. , Bause T. 
Published: January 2008

AbstractDer Einfluss der Größen Substratrauheit und Spritzpartikelgröße auf die Haftung thermisch gespritzter Schichten wurde systematisch untersucht. Neben gängigen Spritzwerkstoffen (Cr2O3, WCCo, NiCr) und Spritzverfahren (Atmosphärisches Plasmaspritzen (APS) und Hochgeschwindigkeitsflammspritzen (HVOF)) wurden bei den Untersuchungen auch verschiedene Substratwerkstoffe (Stahl, Edelstahl, Aluminium) berücksichtigt.
Neuentwicklungen für den Verschleiß‐ und Korrosionsschutz beim Plasma‐Pulver‐Auftragschweißen
Authors: Gebert A. , Wocilka D. , Bouaifi B. , Alaluss K. , Matthes K.‐J. 
Published: January 2008

AbstractHoch verschleißbeständige karbidhaltige Beschichtungen lassen sich durch Auftragschweißen mittels Plasma‐Pulver‐Auftragschweiß‐Verfahren herstellen. Die Verwendung von Vanadiumkarbid vermeidet unerwünschte Reaktionen mit dem Matrixwerkstoff, so dass hochkorrosionsbeständige Schichten auf Fe‐Basis für den Einsatz im Lebensmittel‐ und Meerwasserbereich und auf Ni‐Basis für den Bereich anorganischer Säurebelastung erzeugt werden können.Ein kombinierter Test relativiert den Korrosionseinfluss bei kombinierter Beanspruchung durch Abrasivverschleiß‐ und Korrosion und zeigt das Primat des Verschleißabtrages auf das Einsatzverhalten.
Maßgeschneiderte Tribologie durch Laseroberflächenbehandlung
Authors: Vollertsen F. , Habedank G. , Partes K. 
Published: January 2008

AbstractIn der Industrie gibt es sehr unterschiedliche Anforderungen an tribologische Eigenschaften von Oberflächen. Sowohl die Minimierung als auch die Maximierung von Reibung und/oder Verschleiß können gefordert sein. Die Reibungs‐ und Verschleißeigenschaften hängen vom jeweiligen tribologischen System ab, das aus den Reibpartnern, dem Zwischenstoff und dem Umgebungsmedium besteht. Somit werden für jede Anwendung maßgeschneiderte Oberflächen mit speziellen tribologischen Eigenschaften benötigt. Es werden Beispiele zur Untersuchung und Anwendung laserbasierter Prozesse gezeigt, die die Herstellung von Oberflächen mit sehr unterschiedlichen tribologischen Eigenschaften ermöglichen.Die Wellenlängen, die Leistung, die Intensitätsverteilung und die Strahlqualität der verfügbaren Laser können in einem weiten Bereich variiert werden. Auch die verfügbaren Einrichtungen für die Strahlformung und Strahlführung ermöglichen unterschiedliche Prozesse um Eigenschaften für spezielle Anwendungen maßschneidern zu können. Diese Prozesse sind z. B. das ein‐ oder mehrlagige Laserpulverauftragschweißen um homogene oder gradierte Schichten zu generieren, das Laserlegieren oder –dispergieren und die laserstimulierte Abscheidung von Diamantschichten bei Atmosphärendruck.
Thermisch gespritzte titankarbidverstärkte Eisenbasisschichten als Alternative zu konventionellen karbidischen Werkstoffen
Authors: Bobzin K. , Ernst F. , Zwick J. , Richardt K. , Warda T. , Reisel G. 
Published: January 2008

AbstractHochgeschwindigkeitsflammgespritzte karbidbasierte Schichten haben sich in der Industrie als gängiger Korrosions‐ und Verschleißschutz etabliert. Aufgrund der typischen hohen Karbidanteile von über 75 Gewichtsprozenten zeichnen sie sich durch eine sehr hohe Härte und eine exzellente Verschleißbeständigkeit aus. Jedoch erfordern diese Eigenschaften gleichzeitig auch einen erhöhten Aufwand bei der mechanischen Nachbearbeitung der Schichten. Ein kostengünstiger Nachbearbeitungsprozess mit geometrisch definierter Schneide wie etwa Drehen oder Fräsen ist in der Regel nicht anwendbar, so dass jedes gespritzte Aufmaß mittels Schleifens abgetragen werden muss. Um diesem Problem entgegenzutreten, bietet ein neues karbidbasiertes Werkstoffkonzept viel versprechende Ansätze. Titankarbide mit einem reduzierten Anteil von 33 Gewichtsprozenten eingebettet in eine Eisenmatrix ermöglichen ein deutlich verbessertes Verhalten hinsichtlich der Bearbeitbarkeit.Im Rahmen dieser Arbeit wurde eine Prozessroute zur Herstellung optimierter Pulver entwickelt. Mit entsprechenden Ausgangswerkstoffen sind Spritzversuche durchgeführt worden, um eine Verarbeitbarkeit der titankarbidverstärkten Eisenpulver mittels eines gasbetriebenen und eines flüssigbrennstoffbetriebenen Hochgeschwindigkeitsflammspritz‐Systems (HVOF‐Systems) zu untersuchen. Optimierte Parameter wurden dabei unter Zuhilfenahme der statistischen Versuchsplanung ermittelt. Die Schichten sind im Hinblick auf ihre Mikrostruktur, Härte sowie Phasenzusammensetzung analysiert und mit gesinterten Referenzbauteilen verglichen worden. Des Weiteren wurden die thermisch gespritzten Eisenbasisschichten mit Titankarbidverstärkung wärmebehandelt, um die Resthärtbarkeit der Eisenbasismatrix nach dem thermischen Spritzprozess zu untersuchen.
Antimalarial sulfide trioxanes: a revision of mechanism
Authors: Posner Gary H. , Chang Wonsuk 
Published: January 2008

AbstractThe mechanism by which an antimalarially inactive sulfanyl trioxane reacts with ferrous iron is revised. Although originally proposed to involve a short‐lived high‐valent iron‐oxo intermediate, the revised mechanism involves FeBr2 acting as a weak Lewis acid promoting intramolecular redox chemistry between the peroxide unit and the resident sulfanyl sulfur atom; one of the peroxide oxygen atoms is transferred intramolecularly to the neighboring sulfide sulfur atom, oxidizing it into a sulfoxide and reducing the trioxane into a non‐peroxidic dioxolane. This facile ferrous iron‐triggered conversion of the parent 1,2,4‐trioxane sulfide into the corresponding 1,3‐dioxolane sulfoxide accounts for the observed lack of antimalarial activity of the parent sulfanyl trioxane without invoking the intermediacy of a high‐valent iron‐oxo species. Copyright © 2008 John Wiley & Sons, Ltd.
Aminolysis and pyridinolysis of O‐aryl S‐(4‐nitrophenyl) thiocarbonates in aqueous ethanol. Kinetics and mechanism
Authors: Castro Enrique A. , Aliaga Margarita , Santos José G. 
Published: January 2008

AbstractThe reactions of O‐phenyl S‐(4‐nitrophenyl) thiocarbonate (PNPTC) and O‐(4‐chlorophenyl) S‐(4‐nitrophenyl) thiocarbonate (ClPNPTC) with a series of secondary alicyclic (SA) amines and pyridines are subjected to a kinetic investigation in 44 wt% ethanol–water, at 25.0°C and an ionic strength of 0.2 M. The reactions are followed spectrophotometrically at 420 nm (4‐nitrobenzenethiolate anion appearance). Under amine excess, pseudo‐first‐order rate coefficients (kobs) are found. For all these reactions, plots of kobs vs free amine concentration at constant pH are linear, the slope (kN) being independent of pH. The Brønsted‐type plots (log kN vs pKa of the conjugate acid of the amines) for the reactions of the series of SA amines with PNPTC and ClPNPTC are linear with slopes 0.59 and 0.54, respectively. The values of these slopes are in accordance with a concerted mechanism. The Brønsted‐type plots for the pyridinolysis reactions are biphasic, suggesting a stepwise mechanism with a change in the rate‐determining step, from breakdown to formation of a tetrahedral intermediate, as the basicity of the pyridines increases. Copyright © 2008 John Wiley & Sons, Ltd.
Poly(4‐acryloylmorpholine) oligomers carrying a β‐cyclodextrin residue at one terminus
Authors: Bencini Marco , Ranucci Elisabetta , Ferruti Paolo , Manfredi Amedea , Trotta Francesco , Cavalli Roberta 
Published: January 2008

AbstractA straightforward synthesis of amphiphilic β‐cyclodextrin‐poly(4‐acryloylmorpholine) (β‐CD‐PACM) polymers of controlled molecular weight, consisting of the radical polymerization of 4‐acryloylmorpholine in the presence of 6‐deoxy‐6‐mercapto‐β‐cyclodextrin (β‐CD‐SH) as chain‐transfer agent, has been established. These derivatives carry a single β‐cyclodextrin (β‐CD) moiety at one terminus and their average molecular weight is in the order of 104. Thus, their β‐CD content is ∼ 10% by weight. No evidence of un‐functionalized PACM was found in the final products. The chain‐transfer constant (CT) of β‐CD‐SH was found to be 1.30 by independently determining the reaction constants of both chain‐transfer and propagation reactions. This ensures that the molecular weight, hence the β‐CD content of the polymers, does not significantly vary with conversion. These β‐CD‐PACM polymers are highly soluble in water as well as in several organic solvents such as chloroform and lower alcohols. They proved capable of solubilizing in water poorly soluble drugs such as 9‐[(2‐hydroxyethoxy)methyl]guanine (Acyclovir) and of gradually releasing them in aqueous systems. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1607–1617, 2008
Precise control of microstructure of functionalized polypropylene synthesized by the ansa‐zirconocene/ MAO catalysts
Authors: Hagihara Hideaki , Ishihara Takeshi , The Ban Hoang , Shiono Takeshi 
Published: January 2008

AbstractWe inclusively investigated polymerization behavior and structure of copolymer in the copolymerization of propylene and alkylaluminum‐protected polar allyl monomers. The control of the arrangement of polar group in the copolymer was discussed. It was proved that the location of polar group could be controlled by zirconocene catalyst and a kind of polar monomer. The indenyl or the 2‐methylindenyl ligands of zirconocene were favored to produce end‐functionalized polymers. It was also found that the trimethylaluminum‐protected allylamine and triisobutylaluminum‐protected allylmercaptan had superior ability in the synthesis of end‐functionalized polypropylene. On the other hand, the 2‐methyl‐4‐phenylindenyl ligand produced the copolymers containing both the end‐polar unit and inner‐polar unit at the polymer chains. Terpolymerization of propylene, polar allyl monomer, and 5‐hexen‐1‐ol was also conducted. The NMR study of the terpolymer revealed that both the 5‐hexen‐1‐ol and the polar allyl monomer were incorporated into the polymer chain. It has also become apparent that the polar allyl monomer units predominantly occupied the chain end, while the 5‐hexen‐1‐ol units were located at the inner of main chain. Consequently, we have achieved the synthesis of functionalized polypropylene in which the arrangement of polar group was precisely controlled. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1738–1748, 2008
The formation of γ‐crystal in long‐chain branched polypropylene under supercritical carbon dioxide
Authors: Liao Ruogu , Yu Wei , Zhou Chixing , Yu Fengyuan , Tian Jinghua 
Published: January 2008

AbstractThe crystallization behavior of long‐chain branched (LCB) polypropylene (PP) in the supercritical carbon dioxide (scCO2) atmosphere was investigated to show the influences of LCB and CO2 on the formation of γ‐crystal. The crystallization experiments were performed in CO2 atmosphere with the pressure from 1.3 to 10.4 MPa and temperature between 90 and 130 °C. The effects of LCB level, CO2 pressure, and crystallization temperature on the content of γ‐crystal were investigated. The results showed that the influence of LCB on the formation of γ‐crystal was obvious when PP was crystallized in CO2. The content of γ‐crystal increased with LCB level and reached a maximum of 88.2%. It could be explained that, as LCB increased the chainfolding energy of PP molecular chain and hindered it from folding back into crystal lamella, which made the formation of γ‐crystal easier. However, CO2 was the key factor in the formation of γ‐crystal, and the influence of CO2 on γ‐crystal was much significant than that of LCB. It was believed that the increase of free volume after dissolving of CO2 in PP was helpful in the formation of γ‐crystal. It was found that the content of γ‐crystal increased almost linearly with CO2 pressure (CO2 content), and the contribution of CO2 to γ‐crystal increased with pressure, while that of LCB increased with temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 441–451, 2008
Screen charge transfer by grounded tip on ferroelectric surfaces
Authors: Kim Yunseok , Kim Jiyoon , Bühlmann Simon , Hong Seungbum , Kim Yong Kwan , Kim Seung‐Hyun , No Kwangsoo 
Published: January 2008

AbstractWe have investigated polarization reversal and charge transfer effects by a grounded tip on 50 nm thick ferroelectric thin films using piezoelectric force microscopy and Kelvin force microscopy. We observed the polarization reversal in the center of written domains, and also identified another mechanism, which is the transfer of screen charges toward the grounded tip. In order to overcome these phenomena, we successfully applied a modified read/write scheme featuring a bias voltage. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)