bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die elektronische Ausleihe – rechtliche Rahmenbedingungen für minderjährige Bibliotheksbenutzer
Authors: Katzenberger Ruth , Kieselstein Jana 
Published: August 2014

Zusammenfassung:
Verschiedene Anbieter eröffnen Bibliotheken die Möglichkeit der digitalen Ausleihe: Bibliotheksnutzer können im Rahmen der elektronischen Ausleihe über ein Internetportal ihrer Bibliothek elektronische Medien wie E-Books, E-Music oder E-Papers „ausleihen“. Analog zur Ausleihe eines Printmediums können die Nutzer für eine bestimmte Frist das elektronische Medium downloaden, sich für ausgeliehene Titel vormerken etc. Dieser Beitrag skizziert die Probleme, die sich ergeben können, sobald ein minderjähriger Bibliotheksnutzer aktiv an der elektronischen Ausleihe partizipieren möchte.
Museen, Archiv und Bibliothek – Provenienzforschung in der Klassik Stiftung Weimar
Authors: Haufe Rüdiger , Krokowski Heike , Prölß Peter 
Published: August 2014

Zusammenfassung:
Die Klassik Stiftung Weimar überprüft ihre Bestände auf NS-verfolgungsbedingt entzogenes Kulturgut. Hierzu gehören die Sammlungen der Museen, die Bestände des Goethe- und Schiller-Archivs und der Herzogin Anna Amalia Bibliothek. Die Provenienzforscher müssen nicht nur die Spezifika der unterschiedlichen Objektarten, wie Gemälde, Grafiken, Autographen oder Bücher berücksichtigen, sondern auch die heterogene Vorgeschichte der Einrichtungen.
An additional marine fungal lineage in the Diatrypaceae, Xylariales: Pedumispora rhizophorae
Authors: Klaysuban Anupong , Sakayaroj Jariya , Jones E.B. Gareth 
Published: August 2014

Abstract

Pedumispora rhizophorae, a marine ascomycete reported only from mangrove habitats, was referred to the Diaporthales on the basis of morphological characteristics. To clarify the phylogenetic classification of P. rhizophorae, we re-examined the morphological features of a recent collection of this fungus and evaluated its taxonomic position at the molecular level. Phylogenetic analyses revealed that P. rhizophorae is distantly placed from the Diaporthales, and groups in the Diatrypaceae, Xylariales with strong support. Pedumispora rhizophorae shares many features with members of the Diatrypaceae, including its saprobic habit on decaying plant material, ascomata embedded in a pseudostroma, the presence of paraphyses and pigmented ascospores. However, P. rhizophorae differs from other members of the Diatrypaceae in that this species has apically truncate asci without an apical apparatus, which deliquesce at maturity, whereas diatrypaceous species have persistent long-stalked asci with a more or less truncate apex. Within the Diatrypaceae, the ascospores of most species are allantoid in shape and unicellular, whereas P. rhizophorae possesses septate, filiform ascospores with apical cells lacking cytoplasm. Filiform ascospores and deliquescing asci are common in many unitunicate marine ascomycetes and are regarded as an adaptation to aquatic environment.
Comparison of Improvacuter™ tubes with BD Vacutainer™ tubes for various hormones in the aspects of stability and influence of gel separators
Authors: Zungun Cevdet , Yılmaz Fatma MeriÇ , Boru Elif Guney , Topcuoglu Canan 
Published: August 2014

AbstractValidation of blood collection tubes are important to determine the role of different collection tubes which influence the assurance of laboratory results. We compared two different tubes (ImprovacuterWe compared the results of nine immunoassays performed on UniCelEstradiol and testosterone concentrations obtained from Improvacuter Gel and Clot Activator tubes and BD Vacutainer SST II Advance tubes remained below the lower limits of analytical range for the same analytes while they were within the limits in BD Vacutainer Clot Activator tubes and Improvacuter tubes. Statistical significance of stability was not clinically significant for the hormone parameters we tested in all four tubes.Gel containing tubes (both BD and Improve) gave comparable results with the tubes which do not contain gel except for estradiol and testosterone. The use of gel containing tubes for estradiol and testosterone are not recommended on UniCel
Key criteria for the design of polymeric stabilizers for aqueous titanium dioxide dispersions of high solid content
Authors: Creutz Serge , Jérôme Robert 
Published: August 2014

AbstractAmphiphilic copolymers consisting of an aminated hydrophobic block and a hydrophilic poly(sodium methacrylate) one have been synthesized with different structures and tested as stabilizers for aqueous dispersions of alumina coated titanium dioxide (80 wt.-% solid). The dispersion stability is ruled by the strength of the anchoring of the aminated block onto the pigment and by the dynamics of the micelles formed by the copolymer. Any decrease in the anchoring strength, for example as a result of higher steric hindrance for the adsorbing block or of random rather than blocky distribution of the aminated co-units, is detrimental to the dispersion stability and makes this stability more dependent on the copolymer composition. Indeed, the position and dynamics of the unimers ⇄ micelles equilibrium then control the adsorption of the copolymer on the pigment during the grinding process.
Grafting of living poly(tetrahydrofuran) onto aminodendrimers
Authors: Tanghe Leen M. , Goethals Eric J. 
Published: August 2014

AbstractHybrid polymers consisting of poly(propyleneimine) dendrimers (AstramolTM) and linear poly(tetrahydrofuran) (polyTHF) were obtained by grafting living cationic polyTHF onto the dendrimer. By varying the mole ratio of polyTHF to dendrimer, either modified dendrimers, containing only a few linear polymer chains, or ‘superstar’ polymers, i.e. dendrimers containing a large number of polyTHF chains, were obtained. The average number of grafted chains per dendrimer unit, the grafting degree, could be estimated by means of 1H NMR spectroscopy. For polyTHF with molar mass of 2000 g/mol or lower, all primary amino functions of the dendrimers up to the 5th generation (32 primary amino functions) could be grafted. For polyTHF with molar mass of 4000 g/mol, the maximum grafting degree was lower than the number of primary amino groups available and decreased with increasing dendrimer generation.
Copolymerization of ethylene and 4-vinylcyclohexene by various metallocenes in the presence of Al(iBu)3/[Ph3C][B(C6F5)4]
Authors: Kim Il , Kim Young-tae 
Published: August 2014

AbstractCopolymerizations of ethylene and 4-vinylcyclohexene (VCH) were carried out with isospecific rac-1,2-ethylenebis(1-indenyl)Zr(N(CH3)2)2 [rac-(EBI)Zr(NMe2)2] and syndiospecific isopropylidene(cyclopentadienyl)(9- fluorenyl)ZrMe2 [iPr(Cp)(Flu)ZrMe2] compounds combined with Al(iBu)3/ [Ph3C][B(C6F5)4] as a cocatalyst system. VCH was regioselectively inserted into the copolymer through the vinyl double bond, leaving the endocyclic double bond unreacted. rac-(EBI)Zr(NMe2)2 catalyst showed a higher polymerization rate but lower VCH reactivity than the iPr(Cp)(Flu)ZrMe2 catalyst. The calculation of copolymerization parameters according to Kelen-Tüdös resulted in rE = 131.49 and rVCH = 0.02 for the iPr(Cp)(Flu)ZrMe2 catalyst. When [VCH] in feed was 90.5 mol-%, [VCH] in polymer was 1.88 and 8.04 mol-% for rac-(EBI)Zr(NMe2)2 and iPr(Cp)(Flu)ZrMe2 catalysts, respectively. The resulting copolymers were characterized using NMR, Raman and intrinsic viscosity measurements.
Synthesis and structure-property relationships of novel poly(p-xylylene)s with aromatic substituents
Authors: Ishaque Michael , Wombacher Ralf , Wendorff Joachim H. , Greiner Andreas 
Published: August 2014

AbstractTwo step synthesis of educts for the synthesis of poly(p-xylylene)s was accomplished by Grignard-type coupling reaction of 4-bromotoluene and different aldehydes or p-tolylaldehyde and different aryl bromides followed by conversion of alcohols into corresponding chlorides. Derivatives of poly(p-xylylene) (PPX) were obtained by vapor phase pyrolysis/chemical vapor deposition (CVD) or Gilch-type polymerization of these chlorides. Functional groups along the PPX main chain were introduced by substituted phenyl rings in a-position. The resulting PPXs are soluble under ambient conditions and are amorphous in the solid state. The glass transition temperatures varied only slightly with substituents on the phenyl ring in a-position. Significant enhancement by substituents was found for the thermal stability under nitrogen and a considerable decrease of the surface energies by fluorinated substituents.
PVC/poly(norbornene ester) blends: mixtures of flexible and rigid random coils
Authors: Raubacher Florian , Roth Mark D. , Wendorff Joachim H. 
Published: August 2014

AbstractConsidered are blends of the flexible coil-shaped poly(vinyl chloride) (PVC) and rigid coil-shaped polymers, poly(norbornene ester)s, characterized by strong rotational constraints. The unexpected finding is that the stepwise increase of the specific heat at the glass transition Tg as well as the relaxation of the enthalpy in a temperature interval below Tg (physical aging) vanish as the concentration of poly(norbornene ester)s increases in blends with PVC. The interpretation is that the very specific nature of the glass transition of the rotationally confined poly(norbornene ester) - cooperative librations within the minima of the rotational potential - controls the relaxation properties of the blends. The composition vs. glass transition temperature relation is strongly curved for the blends due to the very small increase of the specific heat of the poly(norbornene ester)s at the glass transition.
Quasi-one-dimensional platinum compound/polymer composites
Authors: Bremi Juliane , Caseri Walter , Smith Paul 
Published: August 2014

AbstractFilms of polymers comprising the quasi-one-dimensional compounds K2[Pt(CN)4]Br0.3, [Pt(NH3)4][PtCl4] (Magnus’ green salt), or [Pt(NH2Oc)4][PtCl4] (Oc = octyl) were prepared from homogeneous solutions followed by solvent evaporation. Above a percolation threshold of ca. 8 - 10% v/v, the composites adopted the semiconductor behavior of K2[Pt(CN)4]Br0.3 or Magnus’ green salt, respectively. In the case of Pt(NH2Oc)4][PtCl4], a network established in the gel state in organic solvents was retained in the composites. Upon orientation of the composites by drawing, dichroism of the materials comprising Magnus’ green salt and polarized light emission with K2[Pt(CN)4]Br0.3 was observed.
Complex formation and selective hydrogen bonding in poly(4-vinylphenol-co-methyl methacrylate)- poly(N-vinylpyrrolidone-co-vinyl acetate) systems
Authors: Akiba Isamu , Seki Takehiro , Akiyama Saburo 
Published: August 2014

AbstractPoly(4-vinylphenol-co-methyl methacrylate) (P(VPh-MMA)) and poly(Nvinylpyrrolidone- co-vinyl acetate) (P(VPr-VAc)) form hydrogen bonding complexes with approx. 1:1 stoichiometry between the VPh unit of P(VPh-MMA) and the VPr unit of P(VPr-VAc) in methanol. These complexes show much higher glass transition temperatures than average polymer blends, suggesting the presence of extremely strong hydrogen bonds. FTIR measurements revealed selective hydrogen bonds between the hydroxy group of VPh units in P(VPh-MMA) and the carbonyl group of VPr units in P(VPr-VAc).
Nanocomposite materials: from lab-scale experiments to prototypes
Authors: Dortmans Ardi , Batenburg Lawrence F. , Koster Theodorus P. M , Nelissen Roel G. , Fischer Hartmut 
Published: August 2014

AbstractA porous PMMA material has been reinforced by clay particles, and properties of the resulting material were evaluated. The clay has been intercalated in a first step by melt-extrusion with a suitable block copolymer. A radical polymerisation reaction after swelling of the intercalated clay with monomer leads in a subsequent step to a nanocomposite material with improved mechanical properties. The optimum load of modified clay was determined to be about 3 to 4 wt.-%. A separation of the reinforcing mineral into single sheets and a subsequent homogeneous incorporation of these sheets into the polymer matrix material increased different mechanical properties by approximately 60%. The lifetime of porous polymer moulds used for pressure casting of sanitary ware has been analysed, modelled and increased. The mechanical behaviour of the existing porous PMMA mould material was analysed using mechanical tests to assess the lifetime under cyclic loading. The relevant stress levels were obtained through in situ strain gauge measurements on a polymer mould for the production of a washing basin. These results were confirmed by means of finite element stress analyses. The lifetime of the washing basin mould under the relevant production conditions was predicted from these data and found to be in good agreement with practical experience. A method to improve the limited lifetime under higher pressures was developed by applying nanodispersed clay as reinforcement. The improved material shows an increase in lifetime under cycling loading by about 1000% in mechanical tests. This improvement is confirmed for a pressure casting mould made of the improved material when used in the actual production process.
Poly(styrene/acrolein) and poly(styrene/α-tert-butoxy-ω- vinylbenzyl-polyglycidol) microspheres. Similarities and differences
Authors: Basinska Teresa 
Published: August 2014

AbstractProperties of two types of polystyrene microspheres with polyacrolein and polyglycidol components in their surface layers are compared. Microspheres were prepared in batch radical emulsifier-free emulsion copolymerizations of styrene with acrolein and/or α-tert-butoxy-ω-vinylbenzyl-polyglycidol macromonomer ( Mn̅ = 2700). Polymerizations were initiated with potassium peroxodisulfate, and the ratio of initial concentrations of styrene and initiator was constant. Number average diameters of poly(styrene/acrolein) (P(S/A)) and of poly(styrene/polyglycidol) (P(S/PGL)) particles were in the range of 200 - 650 nm and decreased with increasing concentration of acrolein and/or polyglycidol in the polymerizing mixtures. The diameter polydispersity of synthesized particles ( Dw ̅ /Dn̅) was usually lower than 1.02. X-ray photoelectron spectroscopy for P(S/A) and P(S/PGL) microspheres showed that surface layers of particles were significantly enriched in polyacrolein or polyglycidol segments, surface fractions of which increased with increasing concentration of the more hydrophilic comonomer in the polymerizing mixture. In the case of P(S/A) particles, the maximal fraction of polyacrolein approached 80 mol-%, whereas for P(S/PGL) particles the maximal surface fraction of PGL was 42 mol-%. Human serum albumin was used as a model protein for studies of attachment onto P(S/A) and P(S/PGL) microspheres. It has been found that for both kinds of particles, the maximal surface concentration of attached (adsorbed and/or covalently immobilized) protein decreased with increasing fraction of hydrophilic component in the particle surface layer (polyacrolein or polyglycidol units). In the case of P(S/A) particles, adsorption always accompanied covalent immobilization of proteins. To the contrary, covalent immobilization of proteins onto the P(S/PGL) microspheres proceeded without adsorption of proteins.
Orientation behaviour of AB and ABC block copolymers under large amplitude oscillatory shear flow in bulk and in concentrated solution
Authors: Stangler Stefan , Abetz Volker 
Published: August 2014

AbstractFlow alignment in a large amplitude oscillatory shear field of lamellar AB and ABC block copolymers has been studied in bulk and in solution. Flow birefringence and 2D small-angle X-ray scattering were used to monitor the orientation. Qualitatively similar orientation behaviour was found for the diluted and the bulk AB block copolymer. While in AB diblock copolymers there is only one interface between the different blocks which may influence the orientation behaviour, in ABC triblock copolymers there are two interfaces within the macromolecule. It will be shown that the introduction of a third block leads to a quite different orientation behaviour in comparison to the AB system. In the lamellar diluted ABC system always the parallel orientation dominates, but it occurs in coexistence with the perpendicular and transverse orientations.
Kinetics of the anionic polymerization of 2-(tertbutyldimethylsilyloxy) ethyl methacrylate
Authors: Breiner Thomas , Schmidt Hans-Werner , Müller Axel H. E. 
Published: August 2014

AbstractThe kinetics and the extent of side reactions of the anionic polymerization of silyl-protected 2-hydroxyethyl methacrylate, 2-(tert-butyldimethylsilyloxy)ethyl methacrylate (TBDMS-HEMA), in tetrahydrofuran (THF) were studied as a function of polymerization temperature. Lithium chloride was added in order to achieve a controlled polymerization. The results of polymerizations at various temperatures are compared with reported data for methyl methacrylate and tert-butyl methacrylate in THF. The activation energy for the studied monomer is lower compared to the other methacrylates. Gel permeation chromatography-viscosity studies show that poly(TBDMS-HEMA) exhibits a more wormlike structure in THF than other polymethacrylates, as indicated by a higher Mark-Houwink exponent, α = 1.025.
Dynamic mechanical properties of crystalline polymer blends. The influence of interface and orientation
Authors: Galeski Andrzej 
Published: August 2014

AbstractModification of the interface changes the viscoelastic response of crystalline polymer blends. For incompatible systems, usually one or more additional tan δ (mechanical loss) peaks appear which reflect the embrittlement of the material. Upon proper compatibilization, the additional peaks disappear and the material becomes tougher. The associated phenomena are explained and illustrated by a number of examples including polypropylene filled with calcium carbonate, polyethylene (PE) and polystyrene compatibilized blends, compatibilized blends of poly(ethylene terephthalate) (PET) with polyethylene as well as polyamide 6/polypropylene- graft-acrylic acid blends. Modes of deformation producing cavitation and cavity free deformation were applied to polymer blends in order to study the influence of molecular orientation and the presence of cavities. It is concluded that interfaces between blend components are weak elements of the blends even in the presence of a compatibilizer. Dynamic mechanical analysis (DMTA) evidenced the occurrence of interactions of the compatibilizer with blend components through temperature shift and intensity change of α, β and γ relaxation processes of polymer components. In oriented films of PET/high-density PE compatibilized blends, the chain segments in the amorphous phase of PET are oriented along machine direction. However, there is a significant anisotropy of chain packing in the plane perpendicular to the drawing direction - the pseudohexagonal packing of chain fragments being in register over the whole film. The PET amorphous phase exhibits anisotropy: DMTA studies show that the glass transition occurs at different temperatures while bending the film in different directions. The source of the ‘anisotropy’ in glass transition is the anisotropy of the amorphous phase: the pseudohexagonal packing and the orientation of chain segments. It is evident that the free volume and frozen fraction of the amorphous phase exhibit some degree of anisotropy. In highly compressed samples free of cavities, the glass transition temperature is shifted to higher temperature as compared to undeformed or drawn and cavitated blends. The shift is the result of high molecular orientation of the amorphous phase of matrix polymer and of the stabilization effect of unbroken interfaces in compressed samples.
Labile hyperbranched poly(triazene ester)s – decomposition behavior and their use as porogens in thermally stable matrix polymers
Authors: Eigner Markus , Voit Brigitte , Estel Katrin , Bartha Johann W. 
Published: August 2014

AbstractHyperbranched polyesters containing labile triazene units in the main chain have been characterized according to their photochemically and thermally induced decomposition behavior. Irradiation with UV light results in a first order decomposition behavior with half-time of 6 to 48 min depending on the structure of the repeating unit. Thermal decomposition starts at about 160°C, and about 50% mass loss are achieved after 15 min at 250°C. Homogeneous incorporation of these globular, functional polymers in thermostable polymer matrices (polyimides and benzocyclobutane-based polymers) was possible. Smooth films from blends of thermostable matrix and up to 50% hyperbranched polymers could be prepared. The hyperbranched component could be destroyed selectively, and the resulting porous matrix has been studied as insulating material for microelectronic multilayer applications.
pH Dependence of the morphology of aqueous micelles formed by polystyrene-block-poly(2-vinylpyridine)-blockpoly( ethylene oxide) copolymers
Authors: Gohy Jean-François , Willet Nicolas , Varshney Sunil K. , Zhang Jian-Xin , Jérôme Robert 
Published: August 2014

AbstractThe morphology of micelles formed by two polystyrene-block-poly(2- vinylpyridine)-block-poly(ethylene oxide) (PS-b-P2VP-b-PEO) copolymers was studied in water by dynamic light scattering and transmission electron microscopy. Spherical micelles were observed that consist of a PS core, a P2VP shell and a PEO corona. The characteristic size of core, shell and corona depends on the copolymer composition. An important increase in micellar size occurs at pH < 5 as a result of P2VP block protonation. The reversibility of this pH effect depends on copolymer composition, too. The conformation of the PEO block plays an important role in this pH driven morphological transition.
Low voltage scanning electron microscopy and atomic force microscopy: state-of-the-art microscopy techniques for investigations of polymer single crystals
Authors: Loos Joachim , Tian Mingwen 
Published: August 2014

AbstractRecent studies on organization and reorganization of polymer single crystals have contributed to the actual discussion on novel approaches towards understanding polymer crystallization and melting. In this context, low voltage scanning electron microscopy (LVSEM) and atomic force microscopy (AFM) demonstrate their importance for the investigation of polymer crystals. Both techniques are able to visualize the morphology of individual single crystals, which have a thickness in the order of 10 to 30 nm and a lateral size of a few micrometers, respectively, without any additional sample treatment such as coating or etching. Main advantage of LVSEM is its large range of observation: LVSEM is suited for fast screening and sample quality evaluation on the millimeter or micrometer level, and at the same time it has the prospect for detection of morphological details with nanometer resolution. The main strength of AFM is twofold: first, its excellent ability for precise quantitative thickness determination of the crystals, and second, using non-contact mode it can act as a non-destructive investigation technique, which allows in situ investigation of dynamic processes during sample treatment. By presenting some results of our studies, e.g., time dependent growth or temperature dependent annealing behavior of individual single crystals, we like to point out the specific advantages of the two techniques for fundamental studies on individual crystals, or ultra-thin polymer layers in general.