bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental design optimization of the capillary electrophoresis separation of leucine enkephalin and its immune complex
Authors: Babar Sheikh Md. Enayetul , Song Eun Joo , Hasan Md. Nabiul , Yoo Young Sook 
Published: August 2007

AbstractTo optimize the capillary electrophoretic separation conditions for leucine enkephalin (LE) and the immune complex of the LE and anti‐LE reaction, an analysis using a three‐level, three‐factorial Box–Behnken design was performed. Three separation parameters, buffer pH (X1), buffer concentration (X2), and applied voltage (X3), were chosen to observe the effect on separation responses. The responses were theoretical plate number, migration time of the LE peak, and resolution between the peaks. The optimum conditions and process validation were determined using statistical regression analysis and surface plot diagrams. The capillary electrophoresis optimum separation conditions were established to be 75 mM phosphate buffer at pH 7.00 with an applied separation voltage of 15 kV. By using the analysis technique, the prediction of responses was satisfactory and process verification yielded values within the ±5% range of the predicted efficiency.
Multidimensional gas chromatographic determination of naphthenes, paraffins, olefins, and aromatics in reformed gasolines
Authors: Lo Coco Filippo , Gasparini Gianni , Lanuzza Francesco 
Published: August 2007

AbstractIncreasing demand for gasoline, changing regulations concerning the reduction of environmental impact, and new refining technologies have led to the refinement of its composition. Nowadays, gasoline is a complex mixture of different fractions deriving from processes of reforming, cracking, isomerization, and alkylation, with the addition of both oxygenated compounds and butanes. There are regulations governing the mixing of various fractions and it is necessary to analyse the composition of these fractions to ensure that the final composition of commercial gasoline satisfies the required specifications. Moreover, analysis of the composition of each fraction enables the technological process of the fraction examined to be modified as appropriate. In this work some reformed gasolines were analysed by multidimensional gas chromatography. This technique allows good separation of the hydrocarbon types in a single analysis and gives the carbon number distribution within each hydrocarbon type.
Nano‐LC‐MS/MS for the monitoring of angiotensin IV in rat brain microdialysates: Limitations and possibilities
Authors: Lanckmans Katrien , Stragier Bart , Sarre Sophie , Smolders Ilse , Michotte Yvette 
Published: August 2007

AbstractTo broaden our knowledge about the central role of the angiotensin IV (Ang IV) peptide, we aimed to monitor its extracellular concentration in the brain using in vivo microdialysis. Ang IV was measured in the dialysates using a previously developed nano‐LC‐MS/MS assay with an LOD of 50 pM. Using this assay, baseline levels of Ang IV in dialysates from different brain structures were undetectable. However, immediately after microdialysis probe insertion, Ang IV could be detected in a concentration that varied between 120 and 187 pM. Using the zero‐net‐flux method, the extracellular levels of Ang IV in the striatum were estimated at 46 pM. These data may indicate that Ang IV is mainly present intracellularly. In addition, Ang IV was clearly measurable after striatal perfusion of Ang II. On the other hand, our nano‐LC‐MS/MS method was successful for the detection of Met‐enkephalin and neurotensin in dialysates from the rat. In conclusion, the nano‐LC‐MS/MS method coupled with microdialysis is well suited to monitor the biologically significant conversion between Ang II and Ang IV in vivo, but physiological extracellular levels of Ang IV appear too low to be detected.
Spherical Polyelectrolyte Brushes as Carriers for Catalytically Active Metal Nanoparticles
Authors: Yu M. , Lu Y. , Schrinner M. , Polzer F. , Ballauff M. 
Published: August 2007

AbstractSummary: We present a study on the catalytic activity of metal nanoparticles immobilized on spherical polyelectrolyte brushes that act as carriers. The spherical polyelectrolyte brushes consist of a solid core of poly(styrene) onto which long chains of poly(2‐methylpropenoyloxyethyl) trimethylammonium chloride are grafted. These positively charged chains form a dense layer of polyelectrolytes on the surface of the core particles (“spherical polyelectrolyte brush”) that tightly binds divalent metal ions, such as AuCl, PdCl or PtCl. The reduction of these ions within the brush layer leads to nearly monodisperse metal nanoparticles. Gold, platinum and palladium nanoparticles with diameters of around 1.25 nm, 2.1 nm and 2.4 nm have been embedded into polyelectrolyte brushes, respectively. The composite particles exhibit excellent colloidal stability. The catalytic activity is investigated by photometrically monitoring the reduction of p‐nitrophenol by an excess of NaBH4 in the presence of the nanoparticles. The kinetic data could be explained by the assumption of a pseudo‐first‐order reaction with regard to p‐nitrophenol. All data demonstrate that spherical polyelectrolyte brushes present an ideal carrier system for metallic nanoparticles.
Structure and Dynamics of Angiotensin (1‐7) Vasoactive Peptide in Aqueous Solution at the Density‐Functional Based Tight‐Binding Level
Authors: de Lima Guilherme Ferreira , Heine Thomas , Duarte Hélio A. 
Published: August 2007

AbstractSummary: Structure and dynamics of heptapeptide Angiotensin (1‐7) in aqueous solution have been investigated by means of density‐functional based tight‐binding molecular dynamics simulations. Solvent‐solute interactions have been studied using a hybrid QM/MM method. The backbone of the heptapeptide remains relatively rigid in aqueous solution compared to gas phase. The solvent acts as a cushion, preventing the free motion of the molecule. Tyrosine is the residue which presents the smallest flexibility and the largest number of water molecules in its first solvation shell. This is in good agreement with the previously published NMR results. The intra– and intermolecular hydrogen bridges have been quantified and analyzed in terms of conformation and stability.
Preparation, Characterization and Applications of Electron‐Beam Curing‐Derived Monolithic Materials
Authors: Bandari Rajendar , Knolle Wolfgang , Buchmeiser Michael R. 
Published: August 2007

AbstractSummary: Acrylate/methacrylate‐based monoliths have been prepared via electron‐ beam (EB) initiated polymerization. These monolithic columns were found suitable for application in the analytical scale separation of various analytes such as proteins. Functionalization of the monolithic columns was accomplished via copolymerization of functional monomers. Selected examples of both synthesis and application will be summarized.
Novel Surface‐Active Succinate Monomers and Initiators for Obtaining Reactive Polymers
Authors: Hevus Ivan , Pikh Zorian 
Published: August 2007

AbstractSummary: Novel surface‐active monomers and initiators were synthesized by successive treatment of cumylsuccinic anhydride with 3‐tert‐butylperoxy‐3‐methyl‐1‐ butanol or poly(propylene glycol) acrylate and 1,3‐propane sultone with triethylamine. The surface tension isotherms on the air‐water solution interface were obtained. The critical micelle concentrations (cmc) as well as the surface tension at the cmc were determined for these substances. The complex thermal analysis of the obtained inisurf was carried out and the possible mechanism of decomposition of its peroxide group was proposed. The synthesized compounds were shown to be suitable reactive surfactants for obtaining styrene latexes.
Synthesis and Characterization of New Functional Poly(ester‐anhydride)s Based on Succinic and Sebacic Acids
Authors: Jaszcz Katarzyna 
Published: August 2007

AbstractSummary: New functional poly(ester‐anhydride)s with allyl pendant groups in the side chains were obtained by polycondensation of sebacic acid (SBA) and poly(3‐allyloxy‐1,2‐propylene succinate) (OSAGE) terminated with carboxyl groups. The carboxyl groups in OSAGE and in SBA were converted to mixed anhydride groups by acetylation with acetic anhydride. After that, prepolymers obtained were condensed in vacuum to yield higher molecular weight poly(ester‐anhydride)s. The influence of SBA and OSAGE content in poly(ester‐anhydride)s on their selected properties e.g. molecular weight, thermal and solubility characteristics as well as degradation rate and mode, were examined. Poly(ester‐anhydride)s were degraded in aqueous buffer of pH 7.4 at 37 °C. The hydrolytic degradation was monitored by determination of weight loss of samples and by determination of ester to anhydride groups ratio.
A Study on the Vinyl Acetate‐co‐Butyl Acrylate Latexes in the Presence of N‐Methylol Acrylamide and Mixed Type Emulsifiers
Authors: Kahraman Ayca , Sarac Ayfer 
Published: August 2007

AbstractSummary: The properties of copolymer latexes depend on the copolymer composition, polymer morphology, initiator, polymerization medium and colloidal characteristics of copolymer particles. Poly(vinyl acetate‐co‐butyl acrylate) latexes with N‐metylol acrylamide were prepared by applying semicontinuous emulsion polymerization. The systems studied were (a) the mixture of anionic sodium lauryl sulfate ether (SELES) with nonionic 30 moles ethoxylated nonyl phenol (NP 30) (50:50), (b) the mixture of anionic sodium lauryl sulfate ether (SELES) with nonionic 30 moles ethoxylated nonyl phenol (NP 30) (70:30), and (c) anionic sodium lauryl sulfate ether (SELES) (100%). The effects of the emulsifier and emulsifier composition on the physicochemical properties of obtained vinyl acetate‐co‐butyl acrylate latex properties in the presence of N‐methylol acrylamide initiated by ammonium persulfate were investigated.
Reactive Blends of Poly(phenylene sulfide)/Hyperbranched Poly(phenylene sulfide)
Authors: Bo Yan , Long Chen , Meifang Zhu , Yanmo Chen 
Published: August 2007

AbstractSummary: Polymer blends consisting of linear poly(phenylene sulfide) (PPS) and hyperbranched PPS (HPPS) were obtained in melt. The solid‐state properties of PPS and their blends were investigated by scanning electron microscopy (SEM), thermogravimetric analyzer (TGA), extraction measurement, differential scanning calorimetry (DSC) and dynamical mechanical analysis (DMA). Blends prepared by melt mixing turned out to be reactive as shown by the TGA and extraction measurement. SEM indicated that no phase separation occurs in PPS/HPPS blends. The degree of crystallization of the blends decreased with increasing HPPS content. Both the storage modulus and loss modulus increased as HPPS content increasing.
Thin Coatings with Photo‐Catalytic Activity Based on Inorganic‐Organic Hybrid Polymers Modified with Anatase Nanoparticles
Authors: Textor Torsten , Schroter Frank , Schollmeyer Eckhard 
Published: August 2007

AbstractSummary: Inorganic‐organic hybrid polymer sols where modified with differently prepared as well as commercial titania nanoparticles, to obtain coatings exhibiting a photo‐catalytic activity for the development of self‐cleaning textiles. The particles synthesized using a sol‐gel‐approach where, amongst others, investigated by XRD to prove the existence of titania crystallized in the anatase structure. The photo‐catalytic activity of the different particles as well of the coatings was compared by the decomposition of astrazone red induced by an irradiation with artificial and solar UV‐radiation. With respect to the underlying aim of the investigation the durability of the effect against washing was tested by standardized washing experiments, showing promising results.
Reactive Compatibilization of Polyethylene/Ground Tire Rubber Inhomogeneous Blends via Interactions of Pre‐Functionalized Polymers in Interface
Authors: Tolstov Alexander , Grigoryeva Olga , Fainleib Alexander , Danilenko Inna , Spanoudaki Anna , Pissis Policarpos , Grenet Jean 
Published: August 2007

AbstractSummary: Reactive compatibilization of recycled low‐ or high‐density polyethylenes (LDPE and HDPE, respectively) and ground tire rubber (GTR) via chemical interactions of pre‐functionalized components in their blend interface has been carried out. Polyethylene component was functionalized with maleic anhydride (MAH) as well as the rubber component was modified via functionalization with MAH or acrylamide (AAm) using chemically or irradiation (γ‐rays) induced grafting techniques. The grafting degree and molecular mass distribution of the functionalized polymers have been measured via FTIR and Size Exclusion Chromatography (SEC) analyses, respectively. Thermoplastic elastomer (TPE) materials based on synthesized reactive polyethylenes and GTR as well as ethylene‐propylene‐diene rubber, EPDM were prepared by dynamic vulcanization of the rubber phase inside thermoplastic (polyethylene) matrix and their phase structure, and main properties have been studied using DSC and mechanical testing. As a final result, the high performance TPE with improved mechanical properties have been developed.
Effect of Specific Interactions on Structure‐Property Relationships of Thermoplastic IPNs Based on Polyurethane and Styrene‐co‐Acrylic Acid Ionomers
Authors: Grigoryeva Olga , Slisenko Olga , Bismarck Alexander , Sergeeva Lyudmila 
Published: August 2007

AbstractSummary: The structure‐property relationships of thermoplastic polymer blends based on poly(ether‐urethane) ionomer (PEUI) and K+‐Ion containing styrene‐acrylic acid random copolymer (S‐co‐AA(K)) have been investigated by different methods. Convergence of the glass transition temperature values of the PEUI and the S‐co‐AA(K) components in the blends studied and improvement of end‐use properties have been found.
ABS‐Modified Epoxy Resins – Curing Kinetics, Polymerization Induced Phase Separation, and Resulting Morphologies
Authors: Müller Yvonne , Häußler Liane , Pionteck Jürgen 
Published: August 2007

AbstractSummary: A commercial diglycidylether of bisphenol A (DGEBA) was modified with an acrylonitrile‐butadiene‐styrene‐copolymer (ABS) and cured with the diamine hardener 4,4′‐diaminodiphenylsulfone (DDS). The curing kinetics was followed by DSC‐ and PVT‐measurements. The polymerization induced phase separation (PIPS) was studied using light microscopy and electron microscopy. While the cloud point analyzed by light microscopy is independent of the ABS content, the curing is accelerated by the presence of ABS. The non‐linear dependency of the curing rate on the ABS content must have its origin in the different morphologies developed due to PIPS.
Synthesis of Specially Designed Adhesion Promoter for Grafting Polypyrrole
Authors: Oberoi Sonia , Jaehne Evelin , Adler Hans‐Jurgen P. 
Published: August 2007

AbstractSummary: Adhesion of conducting polymers to the metal/metal oxide surfaces is not strong. An attempt was made to modify these reactive metal surfaces by N‐derivatised pyrroles. ω‐(pyrrol‐1‐yl alkyl) phosphonic acids with different chain lengths were successfully synthesized and characterized. These derivatives were studied for their adsorption and self‐assembling phenomena onto Ti/TiO2, Ta/Ta2O5 and Al/Al2O3. Various analytical tools were used to characterize the modified surface. Contact angle measurements indicated an increase in hydrophobicity after adsorption that was further confirmed by Surface Plasmon Resonance (SPR). X‐ray Photoelectron Spectroscopy (XPS) studies showed that the molecules are oriented in a fashion such that phosphonic acid group is attached to the metal surface and pyrrole is pointing away from the surface. The oxidation potential of these derivatives was higher than pyrrole as expected. Surface polymerisation was successfully attempted on the modified metal substrates. The polymerised surface was examined under Scanning Electron Microscope (SEM). The new compounds not only function as self‐assembling molecules, they also exhibit a new class of reactive functionalized derivatives that can be used as monomers for polymerisation.
Side‐Chain Sulfonated Poly(arylene ether)s for Fuel Cell Applications
Authors: Meier‐Haack J. , Komber H. , Vogel C. , Butwilowski W. , Schlenstedt K. , Lehmann D. 
Published: August 2007

AbstractSummary: Poly(arylene ether sulfone)s of high molecular weight and narrow molecular weight distribution were obtained by melt polycondensation of 4,4′‐difluorodiphenyl‐ sulfone and trimethylsilylethers of 4,4′‐dihydroxydiphenylsulfone and phenylhydroquinone using CsF as catalyst. Although a block‐like structure of the polymers could be expected from the course of reaction, only a single Tg ranging from 190 °C to 230 °C could be detected by DSC and which depended on the copolymer composition. Contrary to the sulfonation of similar poly(ether ether ketone)s the poly(arylene ether sulfone)s here reported were sulfonated both in the side chain and the main chain. Nonetheless the sulfonated poly(arylene ether sulfone)s showed high hydrolytic stability in water at 130 °C.
Peculiarities of the RuIV‐Alkylidene Triggered Cyclopolymerization of N‐(bis(alkyloxy)aryl)‐ Containing 1,6‐Heptadiynes
Authors: Schmidt Christian , Buchmeiser Michael R. 
Published: August 2007

AbstractSummary: Some peculiarities in the cyclopolymerization of 1,6‐heptadiynes containing an amine‐nitrogen at the 4‐position are presented and discussed within the context of cyclopolymerization of N‐free 1,6‐heptadiynes.
Investigation of Gelling Aqueous Clay Dispersions with Dynamic Light Scattering
Authors: Ferse Bernhard , Richter Sven , Arndt Karl‐Friedrich , Richter Andreas 
Published: August 2007

AbstractSummary:The gelation process of aqueous clay (Laponite XLS, XLG) dispersions and of a photopolymerization system (N‐isopropylacrylamide, Irgacure 2959, Laponite XLS) have been investigated by dynamic light scattering. The gelation threshold could be clearly indicated by a change in the shape of the time‐intensity correlation function.
Self‐Supporting Polymer Films for MEMS Applications
Authors: Nocke Andreas , Wolf Marcus , Budzier Helmut , Monch Jens , Arndt Karl‐Friedrich , Gerlach Gerald 
Published: August 2007

AbstractSummary: The fabrication of a self supporting novolac‐based photoresist layer is demonstrated. A technology is presented using a sacrificial layer of PMMA and a carrier layer of photosensitive PI. The solely use of polymers for the creation of a self‐supporting structure is distinguished by simple processing and relatively low cost materials. Additionally the mechanical stability of the self‐supporting layer is under consideration. Finally the cross‐linking process of the novolac‐based photoresist by curing is discussed using FTIR, DSC and TGA measurements.
Development of anaplastic lymphoma kinase (ALK) small‐molecule inhibitors for cancer therapy
Authors: Li Rongshi , Morris Stephan W. 
Published: August 2007

AbstractAnaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase (RTK) involved in the genesis of several human cancers; indeed, ALK was initially identified in constitutively activated and oncogenic fusion forms—the most common being nucleophosmin (NPM)‐ALK—in a non‐Hodgkin's lymphoma (NHL) known as anaplastic large‐cell lymphoma (ALCL) and subsequent studies identified ALK fusions in the human sarcomas called inflammatory myofibroblastic tumors (IMTs). In addition, two recent reports have suggested that the ALK fusion, TPM4‐ALK, may be involved in the genesis of a subset of esophageal squamous cell carcinomas. While the cause‐effect relationship between ALK fusions and malignancies such as ALCL and IMT is very well established, more circumstantial links implicate the involvement of the full‐length, normal ALK receptor in the genesis of additional malignancies including glioblastoma, neuroblastoma, breast cancer, and others; in these instances, ALK is believed to foster tumorigenesis following activation by autocrine and/or paracrine growth loops involving the reported ALK ligands, pleiotrophin (PTN) and midkine (MK). There are no currently available ALK small‐molecule inhibitors approved for clinical cancer therapy; however, recognition of the variety of malignancies in which ALK may play a causative role has recently begun to prompt developmental efforts in this area. This review provides a succinct summary of normal ALK biology, the confirmed and putative roles of ALK fusions and the full‐length ALK receptor in the development of human cancers, and efforts to target ALK using small‐molecule kinase inhibitors. © 2007 Wiley Periodicals, Inc. Med Res Rev, 28, No. 3, 372–412, 2008
Radioactivity measurements and radiation dose evaluation in tap waters of Central Italy
Authors: Desideri Donatella , Roselli Carla , Assunta Meli Maria , Feduzi Laura , Rongoni Alba , Saetta Daniela 
Published: August 2007

AbstractConsumption of drinking water is very important for human nutrition and its quality must be strictly controlled. A study of radioactivity content in tap water samples collected in the Central Italy was performed in order to check the compliance with recent European regulations. Gross alpha and beta activity, 226Ra, 238U and 234U concentrations were measured. Gross alpha and beta activities were determined by standard ISO 9696 and ISO 9697; for 226Ra determination liquid scintillation was used. 238U and 234U concentrations were determined by alpha spectrometry after separation from matrix by extraction chromatography and electroplating. Recommended WHO guideline activity concentrations for drinking water (0.1 and 1.0 Bq/L for gross alpha and gross beta activity, respectively) are exceeded in two cases for gross alpha activity and are not exceeded in any case for gross beta activity. The concentrations (mBq/L) of 226Ra, 238U and 234U ranged from < 1.70 to 15.3, 0.65 to 48.8 and 0.780 to 51.5, respectively. Effective dose due to the uranium isotopes and radium was calculated for children and adults using the dose coefficients reported by EC Directive 96/29 EURATOM and annual water intake. For all class ages, the doses are quite similar and much lower than 0.1 mSv/year.
Initiation of petroleum formation and antioxidant function – a DFT study of sulfursulfur bond dissociation enthalpies
Authors: Zou Lu‐Feng , Shen Kuang , Fu Yao , Guo Qing‐Xiang 
Published: August 2007

AbstractExperimental studies showed that sulfur radicals play the vital role in petroleum formation.1 Sulfur‐ centered radicals also exhibit activities in antioxidant functions. Here we conduct a theoretical investigation of their precursor‐disulfides. By investigation into substituent effect on sulfursulfur bond dissociation enthalpies (SS BDEs), we would like to find the most effective provider for sulfur radicals. In the present work, 50 alpha‐substituted disulfides and 16 para‐substituted aryl disulfides are studied systematically, with the general formula XS‐SX or HS‐SX. The substituent effect on SS BDEs is found to be very eminent, ranging from 33.2 to 75.0 kcal/mol for alpha‐substituted disulfide, and from 43.7 to 59.7 kcal/mol for para‐substituted phenyl disulfides. We also evaluate the performance of 44 density functional methods to get an accurate prediction. A further study indicates that substituents play a major role in radical energies, instead of molecule energies, which is substantiated by the good linearity between XS‐SX bond dissociation enthalpy (BDE) and HS‐SX BDE. Copyright © 2007 John Wiley & Sons, Ltd.