bluuebunny/crossref_metadata_2025_split huggingface dataset:
Limit Theorems for Supercritical Branching Random Fields
Authors: Dawson Donald A. , Gorostiza Luis G. 
Published: April 2007

AbstractAn infinite particle system in Rd is considered where the initial distribution is POISSONian and each initial particle gives rise to a supercritical age‐dependent branching process with the particles moving randomly in space. Our approach differs from the usual: instead of the point measures determined by the locations of the particles at each time, we take the particles at a “final time” and observe the past histories of their ancestry lines. A law of large numbers and a central limit theorem are proved under a space‐time scaling representing high density of particles and small mean particle lifetime. The fluctuation limit is a generalized GAUSS‐MARKOV process with continuous trajectories and satisfies a deterministic evolution equation with generalized random initial condition. A more precise form of the central limit theorem is obtained in the case of particles performing BROWNian motion and having exponentially distributed lifetime.
Über das globale Verhalten der Normallösungen von x′(t) = (B + t−1A) x(t) und zweier Arten von assoziierten Funktionen
Authors: Schäfke Reinhard 
Published: April 2007

AbstractDas Differentialgleichungssystem x′(t) = (B + t−1 A) x(t) ist über die LAPLACE‐Transformation mit dem parameterabhängigen Differentialgleichungssystem (s − B) v′(s) = (ρ − A) v(s) gekoppelt. In dieser Arbeit werden Lösungen der Systeme untersucht, die an den Singularitäten t = ∞ bzw. s Eigenwert von B bzw. ρ = ∞ ein besonderes Verhalten haben. Es wird gezeigt, daß mehrere Zusammenhangsrelationen zwischen solchen „lokalen”︁ Lösungen eng verknüpft sind. Ein Hauptergebnis ist eine Grenzwertformel für gewisse STOKESsche Koeffizienten des t‐Systems.
On a Probabilistic Model of Infinite Quantum Mechanical Particle Systems
Authors: Fichtner Karl‐Heinz , Freudenberg Wolfganj 
Published: April 2007

AbstractThe usual formulation of quantum mechanics with help of the SCHRÖDINGER equation is possible only for systems with a finite number of particles. In the present paper we propose a new formulation in terms of random point processes which is applicable without any mathematical changes both for finite and for infinite particle systems. Up to now it is restricted to a non‐relativistic description of pure states of boson systems. For finite particle systems this approach is equivalent to the usual HILBERT space formulation of quantum mechanics. Especially we consider POISSON states representing systems of (possibly infinite) independent bosons. Further, we give sufficient conditions for invariance (i.e., for stationary states) and we discuss invariance in the case of a system of coupled harmonic oscillators.
Customers' values, beliefs on sustainable corporate performance, and buying behavior
Authors: Collins Christy M. , Steg Linda , Koning Martine A. S. 
Published: April 2007

AbstractSustainable corporate performance (SCP) requires balancing a corporation's economic, social, and environmental performance. This research explores values, beliefs about the importance of SCP, and buying behaviors of supermarket customers from within a stakeholder framework. Beliefs about the importance of SCP (both social and environmental, but not economic) were found to be related to values. Also, it was found that customers' environmentally responsible buying behaviors were related to their beliefs about the importance of environmental SCP. However their socially responsible buying was not related to their beliefs about the importance of social SCP. Responsible buying behavior may be facilitated by providing reliable information about environmental and social aspects of products. Marketing professionals have a central role to play in moving towards a greater level of corporate transparency and sustainability. © 2007 Wiley Periodicals, Inc.
Infrared spectroscopy of organometallic ions in the gas phase: From model to real world complexes
Authors: MacAleese Luke , Maître Philippe 
Published: April 2007

AbstractGas phase mid‐infrared spectroscopy of molecular ions can nowadays be performed with high performance mass spectrometers coupled to free electron lasers (FEL). The wide and continuous tunability of highly intense FELs in the mid‐infrared region can be exploited for performing infrared multiple photon dissociation (IRMPD) spectroscopy of molecular ions. This review will focus on gas phase IRMPD spectroscopic investigations aiming at probing the structure and the reactivity of transition metal complexes. The performance of infrared spectroscopy for characterizing the coordination mode of polydentate ligands and the spin state of the metal will be illustrated. Infrared spectroscopy has also been exploited to probe the reactivity of metal complexes, and a special attention will be given to the infrared spectroscopy of reactive intermediates. © 2007 Wiley Periodicals, Inc., Mass Spectrom. Rev.
Multiporous Materials From Thermoreversible Poly(vinyledene fluoride) Gels
Authors: Dasgupta Debarshi , Nandi Arun K. 
Published: April 2007

AbstractPoly(vinylidene fluoride)(PVF2) produces thermoreversible gels with alkyl diesters of general formula (CH2)n (COOEt)2 as well as with camphor, a naturally occurring ketone. These gels containing polymer‐solvent intercalates yield multiporous materials when subjected to controlled solvent removal techniques. The micro and meso pores are attributed to polymer‐solvent complexation while the macro pores are formed as a result of removal of the solvent trapped in the fibrillar network. PVF2 –diethyl azelate (DEAZ, n = 6) and PVF2 ‐camphor gels produce porous polymer network when dried by cyclohexane leaching. FESEM images exhibit porous network structures with fibrillar morphology. Mercury intrusion porosimetry (MIP) shows presence of pores having diameter in the range 4 nm–400µm for both the systems. The BJH pore size distribution curves for both systems confirm the presence of mesoporosity. The HK pore size distribution plots indicate that micropores are also created and it also puts evidence of single molecule solvent intercalation between the PVF2 strands. The hysteresis between the extrusion and the intrusion curves indicates the presence of channel type/ink‐bottle type structure in these systems.
Effect of Stereoregular Polyelectrolyte on Protein Thermal Stability
Authors: Zhang Honglei , Saiani Alberto , Guenet Jean‐Michel , Curtis Robin 
Published: April 2007

AbstractMyoglobin was used as a model protein to study the effect of polyelectrolyte on protein thermal stability for solutions. Stereoregular polystyrene sulfonate was used to investigate the effect of chain properties on protein polyion binding affinity. Turbidity measurement indicate stronger binding to protein of atactic polystyrene sulfonate than isotactic polystyrene sulfonate, an effect that might be due to the higher chain flexibility of the atactic form. Differential scanning calorimetry (DSC) and small angle x‐ray (SAXS) scattering indicate the presence of the polyelectrolyte has a destabilizing effect on the protein. The results showed that, although the presence of polyelectrolytes has no effect on myoglobin structure at room temperature at pH 7.4, myoglobin stability is reduced as the temperature is elevated. This effect is linked to the binding of the protein to the polylectrolyte. This binding is probably driven by a combination of electrostatic and hydrophobic interactions, the latter of which are enhanced at higher temperatures.
High‐Frequency Dynamical Behavior of Poly(ethylene glycol)+H2O Mixtures by Brillouin Spectroscopy
Authors: Pochylski M. , Aliotta F. , Błaszczak Z. , Gapiński J. 
Published: April 2007

AbstractBrillouin spectroscopy has been used to examine high‐frequency dynamical behavior of aqueous solutions of poly(ethylene glycol) (Mw ≈ 400g/mol) at 298K in the entire concentration region. It was found that a relaxation process takes place in the experimental frequency window that significantly affects the shape of experimentally recorded spectrum of the density fluctuations (dynamical structure factor). The process detected was attributed to segmental motion of the flexible polymeric chain. The full spectrum analysis of Brillouin spectra has been performed taking advantage of the relaxation function previously used in describing a single relaxation process in dielectric examination of water solutions of PEG 400. The proposed data processing procedure permits a qualitative reproduction of concentration dependencies of the hypersonic wave velocity and absorption measured. The shapes of the concentration dependencies of the relaxation times obtained from the Brillouin and the dielectric spectroscopies are in good agreement over a very broad concentration range, although their absolute values are scaled by the factor of 3. This result indicate that the two processes revealed independently by dielectric and Brillouin spectroscopies, apparently separated in time‐scale, are just the same relaxation process.
Antiseptic Nanocapsule Formation via Controlling Polymer Deposition onto Water‐in‐Oil Miniemulsion Droplets
Authors: Paiphansiri Umaporn , Tangboriboonrat Pramuan , Landfester Katharina 
Published: April 2007

AbstractThe stable nanodroplet was prepared by inverse miniemulsion with an aqueous antiseptic solution dispersed in an organic medium of solvent/nonsolvent mixture containing an oil‐soluble surfactant and the polymer for shell formation. The change in gradient of the solvent/nonsolvent mixture, obtained by heating at 50 °C, led to the precipitation of the polymer in the organic phase and deposition onto the large interphase of the aqueous miniemulsion droplets. The monodisperse polymer nanocapsule, with the size range of 80–240 nm, dispersed in cyclohexane phase was achieved as a function of surfactant concentration. By variation of polymer content, molecular weight and type, an encapsulation efficiency of 20–100% was obtained as detected by proton‐nuclear magnetic resonance spectroscopy measurement. The nanocapsule could be easily transferred into water as continuous phase resulting in aqueous dispersion with nanocapsule containing the antiseptic agent as an aqueous core. The encapsulated amount of the antiseptic agent was evaluated to indicate the durability of the nanocapsule's wall. Additionally, the different types of polymer having glass transition temperature ranging from −60 to 100°C have been successfully used. Currently, the research work on the incorporation of nanocapsules onto natural rubber (NR) latex in order to prepare NR latex glove containing the antiseptic agent nanocapsules is carried out. By using the simple and versatile layer‐by‐layer (LbL) technique based mainly on an electrostatic interaction between oppositely charged species, the deposition of nanocapsules onto NR latex film has successfully been fulfilled.
3D Networks from Self‐Assembling Ionic‐Complementary Octa‐Peptides
Authors: Mohammed Amran , Miller Aline F. , Saiani Alberto 
Published: April 2007

AbstractThe self‐assembly and gelation properties of a set of four octo‐peptides AEAEAKAK, AEAKAEAK, FEFEFKFK and FEFKFEFK based on alanine (A), phenylalanine (F), lysine (K) and glutamic acid (E) were investigated via small angle neutron scattering (SANS). The SANS experiments suggest that AEAKAEAK peptide does not self‐assemble in solution while AEAEAKAK form rod‐like structure i.e.: fibres with a radius of ∼3.3 nm. The latter peptide does not form a gel suggesting that the fibres do not aggregate and form a three‐dimensional network. On the other hand FEFEFKFK and FEFKFEFK peptides were found to form gels for concentrations higher than ∼7 mg ml−1. Below the critical gelation concentration these peptides were also found to form fibrillar structures with smaller average radii of ∼1.7 nm. Above the critical gelation concentration a scattering maximum is observed in the scattered intensity curve. From the position of the maximum a rough estimation of the mesh size of the gel network could be derived and was found to vary between 15 and 30 nm depending on the gel concentration.
Using of Volatile Release Measurements to Understand Polysaccharide Molecular Interactions: An Example with Guar Gum Study
Authors: Aguni Y. , Jouquand C. , Malhiac C. , Grisel M. 
Published: April 2007

AbstractIt is well establishment that polysaccharides are commonly used in many fields of formulation such as food and cosmetic industries as viscosity modifiers or gelling agents. Among the different impacts on the mixture properties, these materials are also known to affect the aroma release or retention thus its sensory perception; the effect depends whether polysaccharide structure induces specific retention or release phenomena from the complex media. Present study deals with studying aroma compounds behaviour from dilute and semi‐dilute aqueous polysaccharide solutions consisting of different guar gum samples.Results allow stating that the whole polymer characteristics as determined by means of structural analysis, protein content determination, rheological and surface tension measurements play a major role on the polysaccharide/aroma compound interaction mechanisms. In particular, results evidence a strong Mannose to Galactose (M/G) ratio effect, thus allowing stating the occurrence of hydrophobic intra and intermolecular mechanism. In addition to that, proteins are demonstrated to only slightly affect the volatile retention.More generally, such an original study allows new highlights concerning macromolecular organisation and interactions in solution.
A Potentiometric and Spectroscopic Study on the Interaction Between Human Immunoglobulin G and Sodium Perfluorooctanoate in Aqueous Solution
Authors: Messina Paula V. , Prieto Gerardo , Sabín Juan , Blanco Elena , Varela Carla , Dodero Verónica , Ruso Juan M. , Sarmiento Félix 
Published: April 2007

AbstractThe interaction between human immunoglobulin G (IgG) and sodium perfluorooctanate (SPFO) has been characterized by a combination of UV‐vis and UV‐CD spectroscopies and ion selective electrodes. The study determined that there were true specific unions between SPFO and IgG. The conformational changes at the bulk solution, induced by SPFO, were well characterized by UV‐vis and UV‐CD spectroscopies. Chemical and thermal unfolding were analysed and the thermodynamic parameters were determined.
Hochtemperaturprüfung – Ein Beitrag zur Werkstoffentwicklung und ‐qualifizierung sowie Simulation der Bauteilbeanspruchung
Authors: Scholz A. , Schwienheer M. , Müller F. , Linn S. , Schein M. , Walther C. , Berger C. 
Published: April 2007

AbstractParallel zur fortlaufenden Weiterentwicklung von Dampf‐ und Gasturbinen sowie Maschinen der Verkehrstechnik einerseits und Randbedingungen wie niedrigem spezifischen Brennstoffverbrauch und hinreichender Umweltverträglichkeit andererseits wird das Ziel verfolgt, durch Anhebung von Prozessparametern wie Temperatur und Druck eine Wirkungsgradsteigerung zu erreichen. Diese Bestrebungen wirken sich insbesondere auf die thermisch und mechanisch hoch beanspruchten Bauteile von thermischen Maschinen und Anlagen aus.Weitgehend unerforscht ist die Wechselwirkung zwischen den durch chemische Zusammensetzung, Herstellungsprozess und Wärmebehandlung bestimmten Gefügemerkmalen, den Änderungen der Mikrostruktur infolge mehraxialer Beanspruchung und der sich daraus ableitenden, zeitabhängigen Verformung und Festigkeit. Vor diesem Hintergrund lassen sich durch verfeinerte Methoden bei der Ermittlung der Werkstoffeigenschaften, deren Modellierung und Übertragung auf das Bauteil Wandstärken optimieren und Wirkungsgrade steigern.Bei der Ermittlung der statischen und zyklischen Werkstoffeigenschaften auch an fehlerbehafteten Proben treten Unsicherheiten auf, die einerseits vom Prüfverfahren und der Auswertung herrühren können, andererseits aber auch vom Werkstoff und dessen Herstellungsverfahren beeinflusst werden. Insgesamt besteht daher die Forderung nach zuverlässiger Ermittlung von Werkstoffeigenschaften und Methoden zur Behandlung von Streubändern und deren mathematisch‐statistischer Beurteilung. Für die Simulation werden konsistente Werkstoffdaten benötigt, die die komplexe Wechselwirkung von Temperatur, Beanspruchungsdauer und Beanspruchungsart beschreiben. Insgesamt handelt es sich um Maßnahmen zur Qualifizierung des gesamten Prozesses von der Herstellung bis zum Betriebsverhalten von Bauteilen.
100 Jahre Staatliche Materialprüfungsanstalt Darmstadt (MPA Darmstadt) und 80 Jahre Fachgebiet und Institut für Werkstoffkunde (IfW) an der Technischen Universität Darmstadt
Authors: Kloos K. H. , Berger C. 
Published: April 2007

AbstractDie vor 100 Jahren gegründete Staatliche Materialprüfungsanstalt Darmstadt (MPA Darmstadt) bildet mit dem 20 Jahre später entstandenen Institut für Werkstoffkunde (IfW) an der TU Darmstadt seit nunmehr 80 Jahren eine Betriebseinheit. Anlässlich ihrer Jubiläen können MPA Darmstadt und IfW auf eine über mehrere Generationen hinweg erfolgreiche Entwicklung hinsichtlich kontinuierlicher und kompetenter Leistungen in Forschung, Lehre, Materialprüfung und vielen verwandten Gebieten zurückblicken. Die dazu verfasste ausführliche Abhandlung beleuchtet die Zeit der Gründung und die bisherigen 5 geschichtlichen Epochen dieser Einrichtung, ihre leitenden Persönlichkeiten und würdigt auch deren z. T. weit über Darmstadt hinaus bekannt gewordenen Verdienste auf dem Gebiet der Materialforschung und –prüfung, aber auch die Leistungen für den Transfer der Erkenntnisse in die Industrie, für die Aufklärung und Abhilfe von Schäden sowie industrienahe Gemeinschaftsforschung und handhabbare Grundlagenforschung. Mit der Institution untrennbar verbunden sind die Namen der früheren Leitungspersönlichkeiten Otto Berndt, August Thum, Hans Sigwart und Heinrich Wiegand. Nach einer Periode mit getrennter Instituts‐ und MPA Leitung durch Karl Heinz Kloos und Anton Bäumel, die von heutigen Mitarbeitern des Hauses rückschauend gewürdigt wird, schließt der Beitrag mit einer Beschreibung der aktuellen Aktivitäten dieses Forschungslaboratoriums und Hochschulinstitutes mit insgesamt 140 Mitarbeitern, das nunmehr seit 12 Jahren (wieder in Personalunion) von Christina Berger geleitet wird.
Antigen‐specific T‐cell activation in hyperplastic thymus in myasthenia gravis
Authors: Utsugisawa Kimiaki , Nagane Yuriko , Suzuki Shigeaki , Kondoh Ryushi 
Published: April 2007

AbstractIn order to determine whether antigen‐specific T‐cell activation by dendritic cells (DCs) is accelerated in thymuses exhibiting lymphofollicular hyperplasia (TLFH) among patients with early‐onset myasthenia gravis (EOMG), we investigated the expression levels of phosphorylated protein kinase C (PKC)θ and the local relationship between the presence of phosphorylated PKCθ and the homing receptor CD44 or CD83, a marker for mature DCs, in samples taken from EOMG patients with early improvement following thymectomy, in remnant thymuses from late‐onset MG patients, and in non‐MG control thymuses. Antigen‐specific T‐cell activation was markedly accelerated in TLFH from EOMG patients. Activated T cells and adjacent DCs appeared to be components of a CD44high cell population circulating from the blood to the thymus. Although there is no convincing evidence that thymectomy is of benefit in MG, in some EOMG patients with early improvement following thymectomy, blockade of CD44‐associated circulation mechanisms is probably the cause for the early benefits of thymectomy and is a potential alternative to thymectomy. Muscle Nerve, 2007
A moving‐mesh finite‐volume method to solve free‐surface seepage problem in arbitrary geometries
Authors: Darbandi M. , Torabi S. O. , Saadat M. , Daghighi Y. , Jarrahbashi D. 
Published: April 2007

AbstractThe main objective of this work is to develop a novel moving‐mesh finite‐volume method capable of solving the seepage problem in domains with arbitrary geometries. One major difficulty in analysing the seepage problem is the position of phreatic boundary which is unknown at the beginning of solution. In the current algorithm, we first choose an arbitrary solution domain with a hypothetical phreatic boundary and distribute the finite volumes therein. Then, we derive the conservative statement on a curvilinear co‐ordinate system for each cell and implement the known boundary conditions all over the solution domain. Defining a consistency factor, the inconsistency between the hypothesis boundary and the known boundary conditions is measured at the phreatic boundary. Subsequently, the preceding mesh is suitably deformed so that its upper boundary matches the new location of the phreatic surface. This tactic results in a moving‐mesh procedure which is continued until the nonlinear boundary conditions are fully satisfied at the phreatic boundary. To validate the developed algorithm, a number of seepage models, which have been previously targeted by the other investigators, are solved. Comparisons between the current results and those of other numerical methods as well as the experimental data show that the current moving‐grid finite‐volume method is highly robust and it provides sufficient accuracy and reliability. Copyright © 2007 John Wiley & Sons, Ltd.
Heuristic solutions for general concave minimum cost network flow problems
Authors: Fontes Dalila B.M.M. , Gonçalves José Fernando 
Published: April 2007

AbstractWe address the single‐source uncapacitated minimum cost network flow problem with general concave cost functions. Exact methods to solve this class of problems in their full generality are only able to address small to medium size instances, since this class of problems is known to be NP‐Hard. Therefore, approximate methods are more suitable. In this work, we present a hybrid approach combining a genetic algorithm with a local search. Randomly generated test problems have been used to test the computational performance of the algorithm. The results obtained for these test problems are compared to optimal solutions obtained by a dynamic programming method for the smaller problem instances and to upper bounds obtained by a local search method for the larger problem instances. From the results reported it can be shown that the hybrid methodology improves upon previous approaches in terms of efficiency and also on the pure genetic algorithm, i.e., without using the local search procedure. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 50(1), 67–76 2007
Incremental flow
Authors: Hartline Jeff , Sharp Alexa 
Published: April 2007

AbstractThis paper defines an incremental version of the maximum flow problem. In this model, the capacities increase over time and the resulting solution is a sequence of flows that build on each other incrementally. Thus far, incremental problems considered in the literature have been built on NP‐complete problems. To the best of our knowledge, our results are the first to find a polynomial time problem whose incremental version is NP‐complete. We present approximation algorithms and hardness results for many versions of this problem, and comment on the relation to multicommodity flow. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 50(1), 77–85 2007