bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antigen Responsive Hydrogels Based on Polymerizable Antibody Fab′ Fragment
Authors: Lu Zheng‐Rong , Kopečková Pavla , Kopeček Jindřich 
Published: June 2003

AbstractNovel antigen responsive hydrogels were prepared by using polymerizable antibody Fab′ fragment from monoclonal anti‐fluorescein BDC1 antibody (IgG2a). To form Fab′ containing hydrogels, the polymerizable Fab′ fragment was copolymerized with N‐isopropylacrylamide (NIPAAm) and N,N′‐methylenebis(acrylamide) (MBAAm; crosslinker) using redox initiators. The thermosensitivity of the hydrogels decreased with increasing Fab′ fragment content. The antigen responsiveness of the hydrogels depended on the Fab′ content, pH, and temperature. When the hydrogels were alternately exposed to antigens fluorescein (FL) and polyamidoamine dendrimer (PAMAM)‐fluorescein (FD), significant reversible volume changes were observed for the hydrogel containing 50% (w/w) Fab′ fragment at 33.7 and 36.8 °C in acetate buffer (10 mM, pH 5.0), respectively, but not at 27.7 °C or in PBS buffer (10 mM, pH 7.4). No noticeable reversible volume changes were observed with pure PNIPAAm hydrogel and the gel containing 10% (w/w) Fab′ fragment.Structure of Fab′ containing hydrogels.magnified imageStructure of Fab′ containing hydrogels.
Concurrent Initiation by Air in the Atom Transfer Radical Polymerization of Methyl Methacrylate
Authors: Nanda Ajaya Kumar , Hong Sung Chul , Matyjaszewski Krzysztof 
Published: June 2003

AbstractThe effect of air in atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was studied. Air initiated polymerization was clearly noticed by the appearance of a low molecular weight peak in the synthesis of high molecular weight poly(isobutylene)‐graft‐poly(methyl methacrylate) (Mn = 5.0 × 105 g/mol). The concentration of chains initiated by oxygen (air) was ≈8 × 10−4 mol/L, determined using the Gladstone‐Dale relationship. The tentatively proposed mechanism for air initiated polymerization was supported by kinetic studies. Similar to typical ATRP systems, the rate of air initiated polymerization increased with temperature, [MMA], amount of air, and activity of the catalyst complex. Polymers with lower polydispersities (Mw/Mn = 1.13) were obtained in the presence of Cu(II) as compared to Cu(I) catalyst complex system.Kinetic plots for the air initiated bulk polymerization of MMA at (•) 20 °C, (▪) 50 °C, and (▴) 90 °C.magnified imageKinetic plots for the air initiated bulk polymerization of MMA at (•) 20 °C, (▪) 50 °C, and (▴) 90 °C.
Xanthate Mediated Living Polymerization of Vinyl Acetate: A Systematic Variation in MADIX/RAFT Agent Structure
Authors: Stenzel Martina H. , Cummins Lyndal , Roberts G. Evan , Davis Thomas P. , Vana Philipp , Barner‐Kowollik Christopher 
Published: June 2003

AbstractEight xanthates were synthesized to induce living free radical polymerization of vinyl acetate. Four compounds, methyl (4‐methoxyphenoxy)carbonothioylsulfanyl acetate, methyl (methoxycarbonothioyl)sulfanyl acetate, methyl (ethoxycarbonothioyl)sulfanyl acetate and methyl (isopropoxycarbonothioyl)sulfanyl acetate were identified as suitable MADIX/RAFT agents, yielding low polydispersity (PDI < 1.2) poly(vinyl acetate) of molecular weights exceeding 5 × 104 g · mol−1. All suitable MADIX/RAFT agents exhibited extended periods of inhibition (0.3 h < tinh < 10 h) and moderate rate retardation. The ability of these compounds to control vinyl acetate polymerization can be correlated with the electron density on the central carbon atom of the xanthate. Electrospray ionization mass spectrometric analysis was performed to complete the investigation on the new MADIX/RAFT agents.magnified image
Block Copolymers from Organomodified Siloxane‐Containing Macroinitiators by Atom Transfer Radical Polymerization
Authors: Strissel Christine , Matyjaszewski Krzysztof , Nuyken Oskar 
Published: June 2003

AbstractAlternating copolymers of 1,3‐diisopropenylbenzene and 1,1,3,3‐tetramethyldisiloxane were synthesized by hydrosilylation–polyaddition. These linear copolymers were functionalized at both ends with 2‐bromoisobutyryl or benzyl chloride moieties. Subsequently, the obtained organomodified siloxane‐containing macroinitiators were successfully used for the preparation of ABA‐type block copolymers by atom transfer radical polymerization (ATRP) of styrene and tert‐butyl acrylate. The high chain‐end functionality of the macroinitiators was confirmed by 1H NMR analysis of the macroinitiators and GPC measurements of the obtained ABA‐type block copolymers. The macroinitiator peaks disappeared in GPC traces after ATRP, and the obtained block copolymers showed a significantly narrower molecular‐weight distribution than the macroinitiators.Synthesis of ABA‐type block copolymers by means of ATRP using organomodified siloxane‐containing, benzyl chloride functionalized macroinitiators.magnified imageSynthesis of ABA‐type block copolymers by means of ATRP using organomodified siloxane‐containing, benzyl chloride functionalized macroinitiators.
Alternating Copolymers of Ethylene and Diolefins Containing Pendent Functional Groups
Authors: Williamson Alex , Fink Gerhard 
Published: June 2003

AbstractThe catalyst [Me2C(Flu)(3‐MeCp)ZrCl2] (1), activated by MAO, was used for the copolymerization of ethylene and 1,7‐octadiene (OD) to form copolymers with pendent double bonds. The properties of the copolymers were strongly dependent on the purity of the comonomer. Formation of ethylene‐rich sequences and increased levels of crosslinking were observed with highly purified 1,7‐octadiene. Catalysts 1 and [Me2Si(Flu)2ZrCl2] (2), activated by MAO, were used for the copolymerization of ethylene and 7‐methyl‐1,6‐octadiene (MOD). In both cases, alternating copolymers were formed with unreacted pendent double bonds. The triad distributions were analyzed by Markovian first‐ and second‐order statistics. Copolymers produced by catalyst 2 were significantly more alternating than copolymers produced by catalyst 1 despite the fact that catalyst 2 is highly symmetrical. Epoxidation of pendent double bonds was examined.
magnified image
Differential Scanning Calorimetry (DSC) for Interdiffusion Studies in PVC/PnBMA Blend: A Quantitative Analysis
Authors: Dlubek Günter , Pompe Gisela , Pionteck Jürgen , Janke Andreas , Kilburn Duncan 
Published: June 2003

AbstractDifferential scanning calorimetry (DSC) was used to study interdiffusion in an initially demixed blend, prepared as particle‐matrix system of the intrinsic miscible polymers poly(vinyl chloride) (PVC, particle, 30 wt.‐%) and poly(butyl methacrylate) (PnBMA, matrix, 70 wt.‐%) during isothermal annealing at 110 °C. A detailed interpretation of the experimental DSC curves was realised using a core‐shell model for the particle matrix system, a calculated concentration‐distance profile across the particle‐matrix interface, and a parameterised concentration dependent curve for the heat flow of mixed blend states derived from experiments. The calculated curves were fitted to the experimental data by variation of the concentration dependence of the diffusion coefficient and its concentration averaged value. Both parameters determine the concentration‐distance profile. From the evolution of the concentration‐distance profile with the annealing time the parameters of the interdiffusion kinetics were analysed. The growth of the mean width of the interfacial phase with time follows a power law with an exponent of k = 0.42. A coefficient of mutual diffusion, $\mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\smile$}}\over D}$, increasing linearly by one order of magnitude from pure PVC to PnBMA, and its concentration averaged value of $\mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\smile$}}\over D} _{{\rm av}} = 2.0 \times 10^{ - 18}$ m2/s were concluded from the experiments.Half width parameter \sigma _{{\rm av}}^* of the interphase for the initially phase‐separated blend PVC/PnBMA = 70/30 wt.‐% vs. the annealing time ta at 110 °C.magnified imageHalf width parameter \sigma _{{\rm av}}^* of the interphase for the initially phase‐separated blend PVC/PnBMA = 70/30 wt.‐% vs. the annealing time ta at 110 °C.
Nanostructure Evolution of Homogeneous Poly(ethylene‐co‐1‐octene) as a Function of Strain
Authors: Stribeck Norbert , Androsch René , Funari Sérgio S. 
Published: June 2003

AbstractPolyolefin elastomers with varying 1‐octene content and different thermal history are studied by wide‐angle X‐ray scattering (WAXS) and small‐angle X‐ray scattering (SAXS) during drawing and after relaxation. The multidimensional chord distribution function (CDF) reveals the nanostructure made from crystallites in the amorphous matrix. Both lamellae and granular crystals are found. Lamellae do not form stacks. The SAXS peak is observed because each lamella is covered by an amorphous layer of well‐defined thickness. Arrangement, rotation, fine chain slip and failure of the domains are directly observed as a function of elongation. During straining and relaxation a well oriented macrolattice with colloidal dimensions but short‐ranging order is formed. Two processes are generating microfibrils, namely (1) arrangement of granular crystallites, and (2) irreversible disruption of lamellae (coarse slip) followed by arrangement of their fragments. The second process stabilizes the colloidal lattice permanently. The higher the comonomer content, the later the irreversible process starts. Quenching from the melt shifts the onset to lower deformation. Deformation of microfibrils is not homogeneous. Instead, there is a limiting long period that cannot be exceeded without disruption. It is related to the position of the maximum in the SAXS pattern (which is almost constant).Long periods in the CDF z(r12, r3) of an ethylene‐octene block copolymer after relaxation from drawing.magnified imageLong periods in the CDF z(r12, r3) of an ethylene‐octene block copolymer after relaxation from drawing.
The Photoinduced Birefringence in Thick Films of Chiral Azodye Copolymers
Authors: Kozlovsky Mikhail V. , Lazarev Vladimir V. 
Published: June 2003

AbstractThe photoinduced birefringence, Δnind, in 19–35 μm thick films has been studied for two series of chiral photochromic liquid crystalline side chain copolymers. The birefringence measured is induced by excitation of the n‐π* band only. The Δnind value induced in 10 min is linear upon concentration of dye moieties but achieves saturation with increase of illumination intensity. Evolution of the birefringence can be described by double exponent growth; the faster exponent is the same for both copolymer series and should relate to the photoselection process, while the slower one should relate mainly to photo‐orientation and differs strongly dependent on chemical structure of photochromic groups. The different behaviour of two copolymer series during the growth governed by the second exponent is interpreted in terms of the “frictional model”. Due to elevated thickness of the films, rather moderate Δnind values result in huge phase retardation up to 270° and more. The materials are promising therefore for holography applications.Chemical structure of the synthesised chiral photochromic copolymers.magnified imageChemical structure of the synthesised chiral photochromic copolymers.
Holomorphic Banach bundles on finite–dimensional q–complete complex manifolds
Authors: Ballico Edoardo 
Published: June 2003

AbstractLet X be a q–complete complex manifold (resp. finite–dimensional Stein space) and E a holomorphic vector bundle on X with fibers isomorphic to a Banach space. Here we prove that Hi(X, E) = 0 for every i > q (resp. i > 0).
Monotone variations of the first eigenvalue for doubly connected domains
Authors: Chu Chie–Ping , Chy Fwu Chih 
Published: June 2003

AbstractThe first Dirichlet eigenvalue for the Laplace operator of a doubly connected plane domain varies with the relative position of the inner hole. Under certain mild hypothesis it decreases as the two boundary curves get closer along some specific direction. We made this observation by analyzing level curves and rearrangement technique.
Positive solutions of a higher order neutral differential equation
Authors: Graef John R. , Qian Chuanxi , Yang Bo 
Published: June 2003

AbstractIn this paper, we consider the higher order neutral delay differential equation

where p : [0, ∞) → (0, ∞) is a continuous function, r > 0 and σ > 0 are constants, and n > 0 is an odd integer. A positive solution x(t) of Eq. (*) is called a Class–I solution if y(t) > 0 and y′(t) < 0 eventually, where y(t) = x(t) – x(t – r). We divide Class–I solutions of Eq. (*) into four types. We first show that every positive solution of Eq. (*) must be of one of these four types. For three of these types, a necessary and sufficient condition is obtained for the existence of such solutions. A necessary condition for the existence of a solution of the fourth type is also obtained. The results are illustrated with examples.
On the Cauchy problem for second order strictly hyperbolic equations with non–regular coefficients
Authors: Hirosawa Fumihiko 
Published: June 2003

AbstractIn this paper we shall consider some necessary and sufficient conditions for well–posedness of second order hyperbolic equations with non–regular coefficients with respect to time. We will derive some optimal regularities for well–posedness from the intensity of singularity to the coefficients by WKB representation of the solution and some counter examples which are constructed by using ideas of Floquet theory.
Exceptional curves on Del Pezzo surfaces
Authors: Knutsen Andreas Leopold 
Published: June 2003

AbstractWe classify all cases of exceptional curves on Del Pezzo surfaces, which turn out to be the smooth plane curves and some other cases with Clifford dimension 3. Moreover, the property of being exceptional holds for all curves in the complete linear system. We use this study to extend the results of Pareschi [17] on the constancy of the gonality and Clifford index of smooth curves in a complete linear system on Del Pezzo surfaces of degrees ≥ 2 to the case of Del Pezzo surfaces of degree 1, where we explicitly classify the cases where the gonality and Clifford index are not constant.
Local properties of Colombeau generalized functions
Authors: Oberguggenberger Michael , Pilipovic Stevan , Scarpalezos Dimitris 
Published: June 2003

AbstractGeneralized functions as mappings defined on the set of generalized points are considered. Local properties of generalized functions, singular support and various types of 𝒢∞–regularity are analyzed. Suppleness and non–flabbyness are proved. Necessary and sufficient conditions on generalized functions extendable out of an open set, are given. Colombeau microfunctions are introduced.
Exfoliated Polylactide/Clay Nanocomposites by In‐Situ Coordination–Insertion Polymerization
Authors: Paul Marie‐Amélie , Alexandre Michaël , Degée Philippe , Calberg Cédric , Jérôme Robert , Dubois Philippe 
Published: June 2003

AbstractPoly(L‐lactide)/layered aluminosilicate nanocomposites were synthesized in bulk by ring‐opening polymerization in the presence of two organo‐modified montmorillonites. When the organo‐modifier consisted of an ammonium cation bearing primary hydroxyl groups, polymerization was initiated by the alcohol functions after adequate activation. The growing polymer chains were directly “grafted” onto the clay surface through the hydroxyl‐functionalized ammonium cations yielding exfoliated nanocomposites with enhanced thermal stability.TEM image of a fully exfoliated Cloisite®30B‐based nanocomposite, showing delamination of the silicate layers.magnified imageTEM image of a fully exfoliated Cloisite®30B‐based nanocomposite, showing delamination of the silicate layers.
Multicomb Polymeric Supramolecules and Their Self‐Organization: Combination of Coordination and Ionic Interactions
Authors: Valkama Sami , Lehtonen Olli , Lappalainen Kristian , Kosonen Harri , Castro Pascal , Repo Timo , Torkkeli Mika , Serimaa Ritva , ten Brinke Gerrit , Leskelä Markku , Ikkala Olli 
Published: June 2003

AbstractSeveral alkyl side chains are bonded to each polymeric repeat unit using both coordinated ligands and electrostatically bound counterions to directly control the interface curvature of the self‐organized structures. 2,6‐Bis(octylaminomethyl)pyridine is Zn‐coordinated to poly(4‐vinylpyridine) (P4VP) with dodecylbenzenesulfonate (DBS) counterions, leading to multicomb polymeric supramolecules, poly[(4VP)Zn(2,6‐bis(octylaminomethyl)pyridine)(DBS)2]. Coordination is evidenced by infrared spectroscopy and visualized by quantum chemical calculations. The amorphous hexagonal self‐organized structures are characterized using X‐ray measurements.magnified image
Structural Characterization of Biocidal Oligoguanidines
Authors: Feiertag Petra , Albert Martin , Ecker‐Eckhofen Eva‐M. , Hayn Gertraud , Hönig Helmut , Oberwalder Hanns W. , Saf Robert , Schmidt Andreas , Schmidt Oskar , Topchiev Dmitrij 
Published: June 2003

AbstractOligomeric guanidines can be obtained by polycondensation of guanidine hydrochloride and 1,2‐bis(2‐aminoethoxy)ethane. A comparative MALDI‐TOF mass spectrometry/NMR spectroscopy study with a 13C‐labeled sample enabled the unambiguous analysis of a guanidine‐based polymer. Among the four major product series unprecedented macrocyclic compounds were detected. The minimum inhibition concentrations for four different microorganisms were determined, showing excellent biocidal activities.
magnified image
Synthesis of Poly(ethylene oxide)s Bearing Functional Groups along the Chain
Authors: Dimitrov Ivaylo V. , Berlinova Iliyana V. 
Published: June 2003

AbstractWell‐defined poly(ethylene oxide)s (PEOs) bearing reactive sites regularly distributed along the chain have been synthesized by the polycondensation of PEO containing a central tertiary amino group with dichloromethane, followed by quaternization with suitable reagents to obtain polyzwitterionic or cationic PEOs with alkyl, allyl, or fluorocarbon pendant groups. The pendant allyl groups have been converted into primary amino groups by reaction with 2‐aminoethanethiol hydrochloride to obtain polyamino‐functionalized PEO.Polyfunctional PEOs bearing different pendant groups.magnified imagePolyfunctional PEOs bearing different pendant groups.
A Self‐Assembling Polythiophene Functionalised with a Cysteine Moiety
Authors: Mucci Adele , Parenti Francesca , Schenetti Luisa 
Published: June 2003

AbstractA new copolymer bearing a cysteine moiety, designed for molecular interaction, metal‐ion detection, and chiral recognition, was synthesised starting from the dibromo derivative of methyl N‐(tert‐butoxycarbonyl)‐S‐thien‐3‐ylcysteinate and distannylthiophene through a Stille coupling reaction. UV‐vis spectroscopy, circular dichroism, NMR spectroscopy, and gel permeation chromatography analyses evidenced that this polymer is able to form self‐assembling structures, through the formation of a hydrogen‐bond network, not only in the solid state but also in solution.
magnified image
Synthesis of Well‐Defined Rod‐Coil‐Rod Polyhexylisocyanate‐block‐polystyrene‐block‐polyhexylisocyanate via One‐Pot Anionic Polymerization
Authors: Ahn Jun‐Hwan , Lee Jae‐Suk 
Published: June 2003

AbstractA rod‐coil‐rod block copolymer, polyhexylisocyanate‐block‐polystyrene‐block‐polyhexylisocyanate, of controlled molecular weight was synthesized quantitatively via living anionic polymerization using potassium naphthalenide in the presence of sodium tetraphenylborate. The use of K+ as the counterion for the polymerization of styrene, and Na+ (NaBPh4) for the polymerization of isocyanate leads to the formation of a well‐controlled novel triblock copolymer.
magnified image
Polymer Bonded Ferrite Materials as EMC Components
Authors: Töpfer J. , Pawlowski B. , Gräbner F. 
Published: June 2003

AbstractPolymer bonded ferrites composed of a mixture of Mn‐Zn ferrites or Ni‐Zn ferrites in a polymer binder (PE, PA) were prepared and tested as electromagnetic‐wave absorbing materials. Test samples and cases were prepared by hot or injection molding. Permeability spectra show loss contributions in the frequency range 100‐1000 MHz. Absorption measurements of injection molded polymer‐ferrite cases display a 3‐5 dB better attenuation characteristics compared to graphite‐loaded polyamide housings.
Potentialunterstützte Herstellung von Metall‐Keramik‐Verbundschichten
Authors: Knote A. , Schindler U. , Krüger H.‐G. , Kern H. 
Published: June 2003

AbstractEine Möglichkeit zur Herstellung von homogenen Metall‐Keramik‐Kompositschichten mit einem hohen Keramikanteil bis zu 60 Vol.‐% soll in dieser Arbeit vorgestellt werden. Diese Methode besteht aus einer Kombination aus elektrophoretischer und galvanischer Abscheidung in aufeinanderfolgenden Schritten. Dabei wird zunächst eine yttriumstabilisierte Zirkonoxidschicht (Tosoh TZ‐8Y) elektrophoretisch auf einem ferritischen Stahl erzeugt, und dann bei 1100 °C zu einer offenporösen Schicht versintert. Im nächsten Schritt wird elektrolytisch Nickel in die Poren der Schicht abgeschieden. Durch eine finale thermische Behandlung war es möglich, die Anbindung der Kompositschicht an das Substrat durch Diffusion der Metallkomponenten zu verbessern.
Neue Technologie zur Herstellung von Wolframschmelzkarbid
Authors: Linke P. , Weiss K. ‐ H. , Nutsch G. 
Published: June 2003

AbstractEine vielversprechende Anwendung der ICP Technologie ist die Sphäroidisierung und Verfestigung von porösen, agglomerierten Partikeln. Die agglomerierten Partikel werden durch ein Sprühtrocknungsprozess hergestellt. Das Ausgangsmaterial besteht aus WC/W2C mit einer Korngröße von 90 – 120 μm und einer Kohlenstoffkonzentration von 4,8 Gew. %. Das Ziel des Projektes war, dichte und sphäroidisierte Partikel, mit einer definierten Kohlenstoffkonzentration, im Bereich von 3,8 – 4,3 Gew.%, herzustellen.
Nanokristalline Werkstoffe hergestellt mit dem Thermischen HF‐Plasma
Authors: Blum J. , Herrmann A. , Schwenk A. , Weiss K.‐H. , Nutsch G. 
Published: June 2003

AbstractDas induktiv gekoppelte Plasma (ICP) eignet sich unter atmosphärischen Bedingungen besonders für das Aufschmelzen und Verdampfen von Werkstoffen. Das elektrodenlose ICP kann ohne Ausnahme mit beliebigen Gasgemischen betrieben werden. Mit der Verwendung eines Argon‐Sauerstoff Hüllgasgemisches des ICP werden Reaktion metall‐organischer, flüssiger Precursoren, die in den heißen Plasmakern injiziert werden, nanokristalline Schichten erzeugt. Für den Beschichtungsprozess wir ein Überschallplasmastrahl eingesetzt. Durch den Aufprall der Partikel auf dem Substrat, das direkt am Düsenausgang des Plasmatrons positioniert ist, werden dünne Schichten hoher Dichte mit Kristallitgrössen von 30‐40 nm erzeugt. Die Struktur und Korngrössen der abgeschiedenen Schichten werden mittels XRD analysiert.
Nanokomposite für die Herstellung oxidischer Matrices keramischer Faserverbundwerkstoffe
Authors: Georgi C. , Schindler U. , Krüger H.‐G. , Kern H. 
Published: June 2003

AbstractKeramische Suspensionen für die Herstellung oxidischer Faserverbundwerkstoffe werden in der Regel aus Submikropulvern hergestellt. Am Beispiel der elektrophoretischen Infiltration von Nextel™ 720‐ und Nextel™ 650‐ Geweben wird gezeigt, daß auch die Verwendung von Nanopulvern bzw. Nanokompositen für den Matrixaufbau von Vorteil sein kann. So gestattet die Koinfiltration des α‐Aluminiumoxid‐Submikropulvers und einer zweiten, nanoskaligen Phase (Zirkonoxid) den Aufbau einer (α‐Aluminiumoxid + Zirkonoxid)‐ Matrix als strukturelles Komposit. Funktionelle Nanokomposite aus Aluminiumoxid und Siliziumoxid ermöglichen die Mullitbildung und ‐verdichtung bei für die Fasern unschädlichen Temperaturen.