bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of BaAl2O4 in the Simultaneous Removal of Soot and NOx
Authors: Li Y.‐J. , Lin H. , Shangguan W.‐F. , Huang Z. 
Published: September 2007

AbstractThe catalytic activity of BaAl2O4 in the simultaneous removal of soot and NOx was evaluated by Temperature Programmed Reaction (TPR). It was found that BaAl2O4 could effectively catalyze the reaction of soot with NOx under various reaction conditions. Compared with non‐catalytic combustion, ignition temperature, Tig, and maximum combustion temperature, Tm, of soot decreased by more than 175 °C and 240 °C, respectively. Tight contact of soot with BaAl2O4, higher O2 content and a lower flow rate of synthesized gases were beneficial to the catalytic reaction. It was confirmed by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analysis, that the reaction of soot with NO2(ad) was the most important factor in simultaneous removal of soot and NOx, in which NO2(ad) existed on BaAl2O4 in the form of monodentate nitrate, bridged nitrate and ionic nitrate.
Numerical Calculations of Spray Roasting Reactors of the Steel Industry with Special Emphasis on Fe2O3‐Particle Formation
Authors: Beck M. , Wirtz S. , Scherer V. , Bärhold F. 
Published: September 2007

AbstractThis work presents numerical calculations for the lay‐out of spray roasting reactors for the steel industry. In these reactors, a pickling liquor based on water and HCl containing FeCl2 is regenerated in a combustor leading to the formation of Fe2O3 particles. For the lay‐out of these reactors, detailed knowledge of the flow and temperature field, the associated gas phase reactions, and especially, of the formation of the Fe2O3 particles is required. An extended particle formation model is presented which is based on earlier work. Finally, results for an industrial spray roasting reactor are given showing the potential of the numerical tools developed for the improvement of the technical lay‐out of such thermal reactors.
The Progression of Synthetic Strategies to Assemble Titanium Complexes Bearing the Terminal Imide Group
Authors: Fout Alison R. , Kilgore Uriah J. , Mindiola Daniel J. 
Published: September 2007

AbstractThe synthesis of terminal titanium imides is described in this account. The incorporation of this functional group has evolved from more simplistic approaches to more complex or unusual methods. Past and current synthetic strategies to incorporate the terminal imide functionality are explained with particular emphasis on low‐coordinate titanium environments bearing this ubiquitous but vital type of motif. More recently, the imide functionality has demonstrated to be a key intermediate for modeling important industrial processes such as the hydrodenitrogenation of crude oil.
Hochdurchsatz‐Methoden in der Festkörperchemie. Schneller zum Ziel
Authors: Bauer Sebastian , Stock Norbert 
Published: September 2007

AbstractHochdurchsatz‐Methoden zeichnen sich gegenüber konventionellen Methoden durch eine größere Effizienz aus. Mittlerweile steht im Bereich der Anorganischen Festkörperchemie und der Materialwissenschaften eine Vielzahl von Werkzeugen zur Verfügung, um die Entdeckung und Optimierung von Materialien durch Verwendung von HD‐Methoden schneller voranzutreiben. Für alle Arbeitstechniken gilt: Das Ausmaß der Automatisierung, Parallelisierung und Miniaturisierung sowie die Integration aller Einzelschritte in einen Gesamtprozess bestimmt die Effizienz einer HD‐Methodik. Durch eine systematische Untersuchung des Parameterraumes und durch sorgfältige Datenevaluierung (möglichst Software‐gestützt) können Trends gefunden werden, die zu einem besseren Verständnis der untersuchten Systeme beitragen.Der vorgestellte Ansatz zur HD‐Untersuchung von Solvothermalreaktionen erlaubt die automatisierte Synthese und Charakterisierung von bis zu 48 Produkten ohne die Proben einzeln manipulieren zu müssen. Der geringe Reagenzienverbrauch zusammen mit der Möglichkeit, die Reaktionen unter identischen Prozessparametern (Temperatur, Zeit, Druck, usw.) durchführen zu können, ermöglichen die systematische Untersuchung eines größeren Parameterraumes. An Hand zahlreicher Beispiele haben wir das Potential von Hochdurchsatz‐ Methoden bei der Entdeckung neuer Verbindungen, der Optimierung von Reaktionen, beim Auffinden von Reaktionstrends sowie der Untersuchung des Einflusses von Prozessparametern gezeigt.
Die Träume von den Schäumen. Detergenzien und Tenside
Authors: Schulze‐Schlarmann Judith , Stubenrauch Cosima 
Published: September 2007

AbstractSchäume kommen in vielen verschiedenen Bereichen in Industrie und Haushalt zur Anwendung, so etwa bei Spülmitteln, Shampoos oder bei der Herstellung von Schaumstoffen. Noch ist aber in den meisten Fällen nicht geklärt, unter welchen Bedingungen Schäume stabil sind oder in sich zusammenfallen. Daher ist es von großem Interesse, die Eigenschaften von Schäumen vorhersagen zu können, wodurch zeit‐ und kostenaufwändige Versuche im “Trial‐and‐error”‐Verfahren vermieden werden könnten. Zu diesem Zweck müssen aber nicht nur die Schäume an sich, sondern auch die Schaumfilme untersucht werden, aus denen der Schaum aufgebaut ist. Einen Einfluss auf die Stabilität haben mit Sicherheit die verwendeten Tenside, deren Konzentration, aber auch Additive wie Parfümöle oder Alkohole. In diesem Beitrag werden Untersuchungen zur Schaum‐ und Schaumfilmstabilität vorgestellt und erste Zusammenhänge erläutert. Allerdings wird auch deutlich, dass es noch viele Fragen gibt, die bisher nicht geklärt werden konnten.
Parabolic recovery of boundary gradients
Authors: Löhner Rainald , Cebral Juan , Appanaboyina Sunil 
Published: September 2007

AbstractA parabolic recovery procedure suited for shear stress and heat flux recovery on surfaces from linear element data is proposed. The information required consists of the usual unknowns at points, as well as gradients recovered at the points that are one layer away from the wall. The procedure has been in use for some time and has consistently delivered superior results as compared with the usual wall shear stress and heat flux obtained from linear finite element method shape functions. Copyright © 2007 John Wiley & Sons, Ltd.
A Straightforward Synthesis of Enantiopure Bicyclic Azetidines
Authors: Sivaprakasam Mangaleswaran , Couty François , David Olivier , Marrot Jérôme , Sridhar Regati , Srinivas Boga , Rama Rao Kakulapati 
Published: September 2007

AbstractEnantiomerically pure 1‐azabicyclo[3.2.0]heptane derivatives were synthesized in a straightforward manner from readily available chiral sources, namely, enantiomerically pure epoxides and L‐proline. The key step of this synthesis relied on a diastereoselective intramolecular alkylation of a proline enolate, which led to an azetidine ring fused to a five‐membered ring. These strained bicyclic nitrogen derivatives were found to be good precursors for the preparation of azepanes, after transformation into the corresponding ammonium trifluoromethanesulfonates followed by reaction with nucleophiles.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Chitosan/polyethylene glycol blend fibers and their properties for drug controlled release
Authors: Wang Qun , Zhang Na , Hu Xianwen , Yang Jianhong , Du Yumin 
Published: September 2007

AbstractFibers of chitosan and polyethylene glycol (PEG), with salicylic acid as model drug incorporated in different concentrations, were obtained by spinning their solution through a viscose‐type spinneret into a coagulating bath containing aqueous tripolyphosphate and ethanol. Chemical, morphological, and mechanical properties characterization were carried out, as well as the studies of the factors that influence the drug releasing from chitosan/PEG fibers. These factors included the component ratio of chitosan and PEG, the loaded amount of salicylic acid, the pH and the ionic strength of the release solution and others. The diameter of the fibers is around 15 ± 3 μm. The best values of the tensile strength at 12.86 cN/tex and breaking elongation at 21.13% of blend fibers were obtained when the PEG content was 8 and 5 wt %, respectively; the water‐retention value of blend fibers increased as the composition of PEG was raised. The results of controlled release tests showed that the amount of salicylic acid released increased with an increase in the proportion of PEG present in the fiber. Moreover, the release rate of drug decreased as the amount of drug loaded in the fiber increased, but the cumulative release amount is increasing. The chitosan/PEG fibers were also sensitive to pH and ionic strength. The release rate was being accelerated by a lower pH and a higher ionic strength, respectively. All the results indicated that the chitosan/PEG fiber was potentially useful in drug delivery systems. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Delivery of rapamycin‐loaded nanoparticle down regulates ICAM‐1 expression and maintains an immunosuppressive profile in human CD34+ progenitor‐derived dendritic cells
Authors: Das Saswati , Haddadi Azita , Veniamin Simona , Samuel John 
Published: September 2007

AbstractImmune responses of dendritic cells (DCs) can be modulated by delivery of adjuvants to alter their maturation profile. The purpose of this study was to generate DCs from CD34+ cells of human cord blood and characterize the effects of poly(D,L‐lactic‐co‐glycolic acid) (PLGA)‐nanoparticle encapsulated rapamycin in generating an immunosuppressive DC. Expression of ICAM‐1 (intercellular adhesion molecule), a key molecule in DC‐T cell interaction was increased in mature DCs in response to lipopolysaccharide (LPS). When rapamycin was encapsulated in the nanoparticle to maintain DCs in the immature state, ICAM‐1 expression was down regulated. When delivered in the free form, rapamycin did not alter the expression of ICAM‐1. Cytokine arrays exhibited an immunosuppressive profile of various cytokines in response to the nanoparticulate delivery of rapamycin. In addition, RT‐PCR data demonstrated the presence of toll like receptor (TLR) 9 transcripts, although our DCs are myeloid in nature. In summary, our study demonstrates that DCs may be rendered immunosuppressive upon delivery of rapamycin‐containing nanoparticles. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Chemical and topographical modification of PHBV surface to promote osteoblast alignment and confinement
Authors: Kenar H. , Kocabas A. , Aydinli A. , Hasirci V. 
Published: September 2007

AbstractProper cell attachment and distribution, and thus stronger association in vivo between a bone implant and native tissue will improve the success of the implant. In this study, the aim was to achieve promotion of attachment and uniform distribution of rat mesenchymal stem cell‐derived osteoblasts by introducing chemical and topographical cues on poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) film surfaces. As the chemical cues, either alkaline phosphatase was covalently immobilized on the film surface to induce deposition of calcium phosphate minerals or fibrinogen was adsorbed to improve cell adhesion. Microgrooves and micropits were introduced on the film surface by negative replication of micropatterned Si wafers. Both chemical cues improved cell attachment and even distribution on the PHBV films, but Fb was more effective especially when combined with the micropatterns. Cell alignment (<10° deviation angle) parallel to chemically modified microgrooves (1, 3, or 8 μm groove width) and on 10 μm‐thick Fb lines printed on the unpatterned films was achieved. The cells on unpatterned and 5 μm‐deep micropitted films were distributed and oriented randomly. Results of this study proved that microtopographies on PHBV can improve osseointegration when combined with chemical cues, and that microgrooves and cell adhesive protein lines on PHBV can guide selective osteoblast adhesion and alignment. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Skeletal metastases: Decreasing tumor burden by targeting the bone microenvironment
Authors: Chirgwin John M. , Guise Theresa A. 
Published: September 2007

AbstractSeveral common cancers often metastasize to the skeleton in advanced disease. Bone metastases are incurable and cause protracted, severe symptoms. Growth of tumor in bone is driven by a vicious cycle: tumor‐secreted factors stimulate bone cells, which in turn release growth factors and cytokines. The bone‐derived factors fuel the vicious cycle by acting back on the tumor cells. The vicious cycle offers novel targets for the treatment of advanced cancers. Treatments can inhibit bone cells (osteoclasts and osteoblasts) that are stimulated by tumor‐secreted factors. Drugs can also inhibit tumor responses to factors enriched in the bone microenvironment, such as transforming growth factor‐β. Animal models show that these approaches, especially combination treatments, can reduce tumor burden. The results suggest a novel paradigm in which tumor growth can be effectively inhibited by drugs that target cells in the bone microenvironment and not the tumor cells themselves. J. Cell. Biochem. 102: 1333–1342, 2007. © 2007 Wiley‐Liss, Inc.
RNA interference‐mediated silencing of the PAR gene inhibits the growth of PC3 cells via the induction of G2/M cell cycle arrest and apoptosis
Authors: Xu Xiao‐Feng , Zhang Zheng‐Yu , Ge Jing‐Ping , Cheng Wen , Zhou Si‐Wei , Zhang Xu , Xu Qi , Wei Zhi‐Feng , Gao Jian‐Ping 
Published: September 2007

AbstractBackgroundThe prostate androgen‐regulated (PAR) gene is ubiquitously overexpressed in prostate cancer (PCa) cells and is involved in proliferation of PCa. However, the mechanism by which the modulation of PAR gene expression elicits its biological effects on PCa cells is not well documented. Here, we investigate the mechanism of PAR depletion inhibiting PCa cell growth.MethodsPAR expression was depleted by small interfering RNA (siRNA) and its subsequent effects on proliferation of PC3 cells were determined by the trypan blue exclusion assay. Flow cytometric analysis provided the evidence for the progression of cell cycle and the induction of apoptosis which was further confirmed by the observation of cleavage of poly(ADP‐ribose) polymerase. Western blot analysis was performed to investigate the involvement of critical molecular events known to regulate the cell cycle and the apoptotic machinery.ResultssiRNA transfection results in a dose‐dependent inhibition of cell growth in PC3 cells by causing G2/M phase cell cycle arrest and apoptosis. The G2/M arrest by PAR depletion was associated with decreased levels of cyclin B1, pCdc2 (Tyr15), Cdc2 and Cdc25C. PAR depletion also was found to result in inhibition of procaspases 9, 8, 6 and 3 with significant increase in the ratio of Bax : Bcl‐2.ConclusionsOur data indicate that PAR depletion induces G2/M arrest via the Cdc25C‐Cdc2/cyclin B1 pathway. Furthermore, the results of the present study point toward involvement of pathways mediated by both caspase 8 and caspase 9 in apoptosis induction by PAR depletion. Copyright © 2007 John Wiley & Sons, Ltd.
Unconventional Methyl Galactan Synthesized via the Thexyldimethylsilyl Intermediate: Preparation, Characterization, and Properties
Authors: Koschella Andreas , Inngjerdingen Kari , Paulsen Berit S. , Morris Gordon A. , Harding Stephen E. , Heinze Thomas 
Published: September 2007

AbstractReaction of a β‐(1 → 4) linked galactan with TDMS chloride followed by methylation and desilylation yields methyl galactans with unconventional functionalization patterns. The products were characterized via FTIR and NMR of the intact polymer and by CE after controlled depolymerization. A TDMS‐derivatized methyl galactan contains differently methylated secondary hydroxyl groups. SEC and analytical ultracentrifugation showed a consistent decrease in the molecular weight after the consecutive reaction steps. Biological studies revealed that the methyl galactans are less active in complement fixation assays as compared with a 3‐O‐methyl galactan‐enriched polysaccharide fraction isolated from Acanthus ebracteatus.magnified image
Proton Conducting Membranes Obtained by Doping Radiation‐Grafted Basic Membrane Matrices with Phosphoric Acid
Authors: Schmidt Christian , Schmidt‐Naake Gudrun 
Published: September 2007

AbstractBy grafting 4‐vinylpyridine (4VP), N‐vinylformamide (NVF), and 1‐vinylimidazole (1VIm) onto electron beam irradiated ETFE and FEP films, the basic membrane matrices ETFE‐graft‐poly(4VP), FEP‐graft‐poly(4VP), ETFE‐graft‐poly(1VIm), and ETFE‐graft‐poly(vinylamine), after subsequent hydrolysis of ETFE‐graft‐poly(NVF), can be obtained. These matrices are doped with phosphoric acid to produce acid–base composite materials that exhibit high proton conductivities up to 100 mS · cm−1 at high temperatures (120 °C) and no humidification. The produced membranes are robust, flexible, and mechanically stable even at high doping levels and endure temperatures of up to 160 °C. Preliminary tests in H2/O2 fuel cells provide power densities between 75 and 150 mA · cm−2 at 120 °C without humidification.magnified image
Molecularly Imprinted Multi‐Layer Core‐Shell Nanoparticles – A Surface Grafting Approach
Authors: Pérez‐Moral Natalia , Mayes Andrew G. 
Published: September 2007

AbstractSurface initiated living‐radical polymerization (SIP) based on dithiocarbamate iniferters has been used to create molecularly imprinted core‐shell (CS) nanoparticles. Using this approach, propranolol, morphine and naproxen have been successfully imprinted in particle shells (the latter could not be imprinted using conventional aqueous‐based CS methods). Rebinding properties of the imprinted particles appear to be similar to those made by alternative methods. The living radical initiation mechanism makes it possible to build complex multi‐layer particles sequentially. As a demonstration, multi‐layer propranolol‐imprinted particles were generated. Two additional functional shells were grown over the imprinted shell, while the propranolol binding was retained, albeit at a reduced level.magnified image
Convergence and stabilization of stress‐point integration in mesh‐free and particle methods
Authors: Fries Thomas‐Peter , Belytschko Ted 
Published: September 2007

AbstractStress‐point integration provides significant reductions in the computational effort of mesh‐free Galerkin methods by using fewer integration points, and thus facilitates the use of mesh‐free methods in applications where full integration would be prohibitively expensive. The influence of stress‐point integration on the convergence and stability properties of mesh‐free methods is studied. It is shown by numerical examples that for regular nodal arrangements, good rates of convergence can be achieved. For non‐uniform nodal arrangements, stress‐point integration is associated with a mild instability which is manifested by small oscillations. Addition of stabilization improves the rates of convergence significantly. The stability properties are investigated by an eigenvalue study of the Laplace operator. It is found that the eigenvalues of the stress‐point quadrature models are between those of full integration and nodal integration. Stabilized stress‐point
integration is proposed in order to improve convergence and stability properties. Copyright © 2007 John Wiley & Sons, Ltd.
Influence of different process and material parameters on chemical foaming of fluorinated ethylene propylene copolymers
Authors: Zirkel Larissa , Münstedt Helmut 
Published: September 2007

AbstractIn this article, the chemical foaming of fluorinated ethylene propylene copolymers (FEP) is investigated. For the laboratory scale foam extrusion process, a chemical blowing agent adapted to the high melting temperature of FEP had to be found. Foaming experiments were carried out varying process and material parameters. Foam densities as well as cellular structures were analyzed to characterize how the parameters influence the foaming behavior of the FEP melt. An increasing rate of the foam extrusion caused an augmentation of cell numbers at a simultaneous decrease of their diameters. Moreover, a pronounced reduction of the foam density with increasing output rate could be observed. Changing the temperature of the foam extrusion, an optimum in density reduction and homogeneity of the cell size was found. Furthermore, the influence of an appropriate nucleation agent on the resulting geometry and amount of cells was investigated. Though the chemical blowing agent itself can act as an implement for nucleating cell growth, an addition of 10 wt% of calcium fluoride particles showed a significant augmentation in cell quantity. For the chemical foam extrusion process, three FEP with different viscosities were characterized. With decreasing viscosity, a reduction in foam density could be observed for all temperatures. POLYM. ENG. SCI., 47:1740–1749, 2007. © 2007 Society of Plastics Engineers
Eco‐plastics: Morphological and mechanical properties of recycled poly(carbonate)‐crushed rubber (rPC‐CR) blends
Authors: Zribi K. , Elleuch K. , Feller J.F. , Bourmaud A. , Elleuch B. 
Published: September 2007

AbstractCrushed tire rubber particles (CR) have been dispersed into a recycled poly(carbonate) matrix (rPC) to obtain an eco‐friendly plastic (EFP). A positive synergy was expected from the association of an elastomeric phase to a tough thermoplastic matrix, helping on the other hand to develop a plastic with low impact on the environment. Mechanical melt‐mixing alone cannot provide a suitable interface, and led to blends with poor mechanical properties. Consequently, we have investigated different strategies to improve the EFP properties: First, the rubber surface has been treated by flaming or washing with dichloromethane and second, two copolymers, poly(ethylene‐co‐ethyl acrylate‐tert‐hydroxyl methacrylate) (E‐EA‐MAH) and poly(ethylene‐co‐methyl acrylate‐ter‐glycidyl methacrylate) (E‐MA‐GMA), were used to compatibilize CR particles with rPC matrix by reactive melt‐mixing in an internal mixer. The resulting blends mechanical properties were studied through static tension experiments and interpreted to the light of electronic microscopy fractography analysis and nanoindentation experiments. Significant gain of mechanical properties can be obtained by decreasing CR size under 140 μm (especially for CR contents between 5 and 20% m/m). To reach similar properties with rubber particles of diameter over 140 μm (but under 350 μm), it is necessary to activate their surface by either dichloromethane washing or flaming. Additional use of a compatibilizer extends the plastic behaviour domain of the EFP. rPC‐20% w/w CR is the best alternative material of our study. POLYM. ENG. SCI., 47:1768–1776, 2007. © 2007 Society of Plastics Engineers
Crosslinking of rotational molding foams of polyethylene
Authors: Marcilla A. , García‐Quesada J.C. , Ruiz‐Femenia R. , Beltrán M.I. 
Published: September 2007

AbstractRotational molding of foamed polyethylene has increasingly become an important process in industry due to its ability to produce innovative and high added value parts with little specialist equipment required. The polyolefin foam production tends to achieve the highest possible cell size uniformity and cell size reduction. To improve the cell morphology of the PE foams, the cell coalescence and coarsening might be suppressed, which can be accomplished preserving the melt strength of the polymer during processing. With this aim, in this work two peroxides have been used to enhance the melt strength of a linear low‐density polyethylene by chemical crosslinking. The moldings have been processed at different oven residence times and they have been characterized according to their density, gel content, bubble size distribution and impact strength. Despite the lower crosslinking degree attained by the crosslinked foams, the results show an enhancement in the cell morphology of these moldings, which are able to keep their cell size distribution even with the longest processing times and consequently the processing window of these rotational molding foams is widened. POLYM. ENG. SCI., 47:1804–1812, 2007. © 2007 Society of Plastics Engineers