bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon nanowire‐based temperature sensor
Authors: Zaitsev Alexander M. , Levine Alfred M. , Zaidi Sohail H. 
Published: September 2007

AbstractA temperature sensor based on an array of carbon nanowires written by a 30 keV Ga+ focused ion beam on diamond substrate has been developed. The temperature sensitivity of the electrical conductuctance between the nanowires is explained by the thermal activation of charge carriers in a heterostructure graphite‐diamond over an energy barrier of 0.24 eV. The sensor shows an exponential increase of current with temperature at a rate of 0.1 dB/°C in the temperature range from 40 to 140 °C. The advantages of the novel carbon nanowire sensor are light blindness, compatibility with carbon nanotechnology, reproducibility and simplicity of fabrication. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of Carbon 1s Core Ionization Energies in Saturated Molecules
Authors: Cao Chenzhong 
Published: September 2007

AbstractThe Slater‐like model was established to calculate the carbon 1s core ionization energies in saturated molecules. Using the atomic Electron Affinity (EA), average valence‐shell electron energy EI and polarizability α as parameters, the charge effect, the relaxation effect, and the electrostatic field effect were evaluated for the C 1s core ionization energies in saturated molecules. The charge effect was scaled by electronegativity difference (the difference in EA and the difference in EI between the carbon atom that is being ionized and its adjacent atoms). The relaxation effect (induced dipole) was scaled by the charge on the ionized carbon atom together with the polarizability of all other atoms in the molecules. The electrostatic field effect was scaled using the charges of the other atoms in molecular backbone divided by the distance between the ionized carbon atom and the other backbone atom. Furthermore, the electrostatic relaxation effect ΔSi of C 1s electron was expressed by the above three effects. By introducing the ΔSi into the Slater model, a Slater‐like model was obtained to calculate the C 1s core ionization energy E1,C of halomethane and more complex molecules, whose correlation coefficient r is 0.99955 and the average absolute error between the calculated and the experimental values for 63 compounds is only 0.079 eV. Also the crosscorrelation was tested by the Leave‐One‐Out (LOO) crossvalidation method, and the correlation coefficient rcv=0.99941 and an average absolute error of 0.091 eV between the predicted and the experimental values were obtained. Using the obtained model, some C 1s electron ionization energies were predicted, and the results were in agreement with the experimental values. Application of the developed approach to other systems was also tested.
A new method of accurate pKb determinations for some organic amines
Authors: Jia Zhao‐Kun , Zhang Shu‐Fang , Zhou Zheng‐Yu , Zhang An‐Guo , Hou Rui‐Yan 
Published: September 2007

AbstractThe accurate pKb determinations for some amines have been investigated using the combination of the extended clusters‐continuum model with the polarizable continuum solvation model. The formation of molecular clusters by means of the amines wrapped up with water molecules leads to the weakness of the mutual function between the polar solvents and the amines, and, hence, the accuracy of pKb has been enhanced by using a coherent and well‐defined approach without external approximations or experimental data. The calculations are performed at the HF/6‐311++G(d, p) level and agreed well with experimental data because electron correlation effect cancels mutually in the calculated value of ΔG which is not an absolute value, but a relative value. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Theoretical study of the oxidative polymerization of aniline with peroxydisulfate: Tetramer formation
Authors: Ćirić‐Marjanović Gordana , Trchová Miroslava , Stejskal Jaroslav 
Published: September 2007

AbstractSemi‐empirical quantum chemical study of the oxidative polymerization of aniline with ammonium peroxydisulfate, in aqueous solutions without added acid, has been based on the MNDO‐PM3 computations of thermodynamic, redox, and acid–base properties of reactive species and the intermediates, combined with the MM2 molecular mechanics force‐field method and conductor‐like screening model of solvation. The main reaction routes of aniline tetramerization are proposed. The regioselectivity of the formation of aniline tetramers by redox and electrophilic aromatic substitution reactions is analyzed. It was proved that the linear NC4 coupled tetra‐aniline is formed as a dominant product by three different pathways: comproportionation redox reaction between N‐phenyl‐1,4‐benzoquinonediimine and 4‐aminodiphenylamine, the one‐electron oxidation of aniline with its half‐oxidized NC4 coupled trimer, and the electrophilic aromatic substitution reaction of aniline with fully oxidized NC4 coupled trianiline nitrenium cation. The electrophilic aromatic substitution reaction of the NC4 coupled aniline trimer with aniline nitrenium cation, as well as the oxidation of aniline with half‐oxidized branched trimer, lead to the branched aniline tetramers. The competing character of different tetramerization routes is highlighted. The oxidative intramolecular cyclization of branched oligoanilines and polyaniline, leading to the generation of substituted phenazine units, has been predicted to accompany the classical routes of the polymerization of aniline. Various molecular (branched vs. linear) oligomeric structures produced at different level of acidity during the course of polymerization and their impact on the formation of supramolecular structures of conducting polyaniline (nanorods and nanotubes vs. granular morphology), are discussed. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Random mappings with exchangeable in‐degrees
Authors: Hansen Jennie C. , Jaworski Jerzy 
Published: September 2007

AbstractIn this article we introduce a new random mapping model, $T_n^{\hat D}$, which maps the set {1,2,…,n} into itself. The random mapping $T_n^{\hat D}$ is constructed using a collection of exchangeable random variables $\hat{D}_1, \ldots.,\hat{D}_n$ which satisfy $\sum_{i=1}^n\hat{D}_i=n$. In the random digraph, $G_n^{\hat D}$, which represents the mapping $T_n^{\hat D}$, the in‐degree sequence for the vertices is given by the variables $\hat{D}_1, \hat{D}_2, \ldots, \hat{D}_n$, and, in some sense, $G_n^{\hat D}$ can be viewed as an analogue of the general independent degree models from random graph theory. We show that the distribution of the number of cyclic points, the number of components, and the size of a typical component can be expressed in terms of expectations of various functions of $\hat{D}_1, \hat{D}_2, \ldots, \hat{D}_n$. We also consider two special examples of $T_n^{\hat D}$ which correspond to random mappings with preferential and anti‐preferential attachment, respectively, and determine, for these examples, exact and asymptotic distributions for the statistics mentioned above. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008
Analyzing linear mergers
Authors: Dvir Zeev , Raz Ran 
Published: September 2007

AbstractMergers are functions that transform k (possibly dependent) random sources (distributions) into a single random source, in a way that ensures that if one of the input sources has min‐entropy rate δ then the output has min‐entropy rate close to δ. Mergers have proven to be a very useful tool in explicit constructions of extractors and condensers, and are also interesting objects in their own right. In this work we give a refined analysis of the merger constructed by [Raz, STOC'05] (based on [Lu, Reingold, Vadhan, and Wigderson, STOC'03 pp. 602–611, 2003]). Our analysis uses min‐entropy instead of Shannon's entropy to derive tighter results than the ones obtained in [Raz STOC'05].We show that for every constant r and k it is possible to construct a merger that takes as input k strings of length n bits each, and outputs a string of length n/r bits, such that if one of the input sources has min‐entropy b, the output will be close to having min‐entropy b/(r + 1). This merger uses a constant number of additional uniform bits. One advantage of our analysis is that b (the min‐entropy of the “good” source) can be as small as a constant (this constant depends on r and k), while in the analysis given in [Raz STOC'05], b is required to be linear in n. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008
Sampling subproblems of heterogeneous Max‐Cut problems and approximation algorithms
Authors: Drineas Petros , Kannan Ravi , Mahoney Michael W. 
Published: September 2007

AbstractRecent work in the analysis of randomized approximation algorithms forNP‐hard optimization problems has involved approximating the solution to a problem by the solution of a related subproblem of constant size, where the subproblem is constructed by sampling elements of the original problem uniformly at random. In light of interest in problems with a heterogeneous structure, for which uniform sampling might be expected to yield suboptimal results, we investigate the use of nonuniform sampling probabilities. We develop and analyze an algorithm which uses a novel sampling method to obtain improved bounds for approximating the Max‐Cut of a graph. In particular, we show that by judicious choice of sampling probabilities one can obtain error bounds that are superior to the ones obtained by uniform sampling, both for unweighted and weighted versions of Max‐Cut. Of at least as much interest as the results we derive are the techniques we use. The first technique is a method to compute a compressed approximate decomposition of a matrix as the product of three smaller matrices, each of which has several appealing properties. The second technique is a method to approximate the feasibility or infeasibility of a large linear program by checking the feasibility or infeasibility of a nonuniformly randomly chosen subprogram of the original linear program. We expect that these and related techniques will prove fruitful for the future development of randomized approximation algorithms for problems whose input instances contain heterogeneities. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008
Direct Low‐Temperature Synthesis of Rutile Nanostructures in Ionic Liquids
Authors: Kaper Helena , Endres Frank , Djerdj Igor , Antonietti Markus , Smarsly Bernd M. , Maier Joachim , Hu Yong‐Sheng 
Published: September 2007

AbstractThe direct synthesis of crystalline titania nanorods by sol–gel chemistry in a special ionic liquid is reported. Unexpectedly, the high‐temperature modification, rutile, is obtained directly under ambient conditions. X‐ray diffraction and high‐resolution transmission electron microscopy measurements support the highly crystalline and structural quality of the sample. The phase‐directing property of the ionic liquids is attributable to the imide group in the counter ion, which exhibits strong interaction with specific rutile faces. Lithium insertion experiments were performed and revealed high and reversible loading capacities of up to 200 mAh g−1.
Hybridization Kinetics and Thermodynamics of DNA Adsorbed to Individually Dispersed Single‐Walled Carbon Nanotubes
Authors: Jeng Esther S. , Barone Paul W. , Nelson John D. , Strano Michael S. 
Published: September 2007

AbstractHybridization of DNA adsorbed to single‐walled carbon nanotubes in solution has much slower kinetics than free solution DNA, and can be detected through a blue shift in the near‐infrared nanotube fluorescence. Adsorption of the receptor DNA strand to the nanotube surface is consistent with models of polyelectrolyte adsorption on charged surfaces, introducing both entropic (46.8 cal mol−1 K−1) and activation energy (20.4 kcal mol−1) barriers to the hybridization, which are greater than free solution values (31.9 cal mol−1 K−1 and 12.9 kcal mol−1) at 25 °C. The increased hybridization barriers on the nanotube result in exceedingly slow kinetics for hybridization with t1/2=3.4 h, compared to the free solution value of t1/2=4 min. These results have significant implications for nanotube and nanowire biosensors.
A multiple layer model to compare RNA secondary structures
Authors: Allali Julien , Sagot Marie‐France 
Published: September 2007

AbstractWe formally introduce a new data structure, called MiGaL for ‘Multiple Graph Layer’, composed of various graphs linked together by relations of abstraction/refinement. The new structure is useful for representing information that can be described at different levels of abstraction, each level corresponding to a graph. We then propose an algorithm for comparing two MiGaLs. The algorithm performs a step‐by‐step comparison starting with the most ‘abstract’ level. The result of the comparison at a given step is communicated to the next step using a special colouring scheme. MiGaLs represent a very natural model for comparing RNA secondary structures that may be seen at different levels of detail, going from the sequence of nucleotides, single or paired with another to participate in a helix, to the network of multiple loops that is believed to represent the most conserved part of RNAs having similar function. We therefore show how one can use MiGaLs to very efficiently compare two RNAs of any size at different levels of detail. Copyright © 2007 John Wiley & Sons, Ltd.
Anlagendynamik, Belastungen und Entwurfanforderungen von Offshore‐Windenergieanlagen und deren Tragstruktur
Authors: Kühn Martin , Argyriadis Kimon 
Published: September 2007

AbstractDie Auslegung der Tragstrukturen von Offshore‐Windenergieanlagen stellt eine neue und anspruchsvolle technische und wirtschaftliche Herausforderung dar. Der vorliegende Übersichtsartikel präsentiert in kompakter Form einige wesentliche Aspekte der Eigenschaften von Offshore‐WEA, deren Lastannahmen, Berechnungsverfahren und Richtlinien. Beispiele teils fiktiver, teils realer Offshore‐Windenergieanlagen von 1,5 bis 5 MW Leistung werden zur Veranschaulichung der Bedeutung einer die Maschine und die Tragstruktur umfassenden integrierten Betrachtung, des Einflusses der lokalen Standortbedingungen und von Besonderheiten in der Berechnung von Extrem‐ sowie Betriebsfestigkeitsbelastungen verwendet. Abschließend wird ein Ausblick auf weitere Entwicklungen gegeben.
Die neue Rheinbrücke Wesel – Entwurfsplanung und Ausschreibung
Authors: Gebert Gregor , Bohm Stefan , Sprinke Peter , Hamme Markus , Löckmann Hans , Reinsch Helmut 
Published: September 2007

AbstractDie neue Rheinbrücke Wesel im Zuge der B 58n befindet sich zur Zeit in Bau. Das insgesamt 773 m lange Bauwerk wird als einhüftige Schrägseilbrücke mit einer Hauptöffnung von 335 m ausgeführt. Mit seinem 130 m hohen Pylon wird das Bauwerk die flache Rheinlandschaft nachhaltig prägen. Die Brückenkonstruktion unterteilt sich in den 409 m langen Stahlüberbau der Strombrücke und die 364 m lange Spannbetonbrücke über das linksrheinische Vorland. Beide Abschnitte sind biegesteif miteinander gekoppelt. Der Aufsatz beschreibt die statischen, konstruktiven und gestalterischen Besonderheiten des Bauwerks aus der Sicht der Entwurfsverfasser und geht auf die Ausschreibung und Vergabe dieses herausragenden Bauvorhabens ein.
Increased binding potential of [11C]raclopride during unilateral continuous microinjection of nicotine in rat striatum observed by positron emission tomography
Authors: Tajima Toshihisa , Hatano Kentaro , Suzuki Mitsuru , Ogawa Mikako , Sakiyama Yojiro , Kato Takashi , Endo Hidetoshi , Miura Hisayuki , Matsubara Michitaka , Ito Kengo 
Published: September 2007

AbstractNicotine injections and nicotine skin patches significantly improve attention, memory, and learning in Alzheimer's disease. In animal studies, nicotine improves the performance of various memory‐related tasks, an effect that is thought to be mediated by the neuronal dopaminergic system as systemic administration of nicotine decreased [11C]raclopride binding in the anesthetized state. Since high doses of systemically administered nicotine are harmful, we administrated it directly into the rat striatum via microdialysis. We then examined the acute effects of continuous central administration of high doses of nicotine on striatal dopamine concentrations by measuring [11C]raclopride binding by positron emission tomography. The concentration of dopamine in the dialysates was significantly increased from basal levels when microdialysis with 100 mM nicotine was initiated. However, contrary to expectations, the binding potential (BP) of [11C]raclopride in the nicotine‐perfused striatum was significantly higher than that in control striatum. Preinjection of mecamylamine (3 mg/kg), a nicotinic antagonist, had no effect on either extracellular dopamine levels or on the BP of [11C]raclopride. These findings suggest that the high dose of local nicotine administration induced mecamylamine‐insensitive local increases in extracellular dopamine, but might have decreased the total amount of extracellular dopamine in the striatum. Synapse 61:943–950, 2007. © 2007 Wiley‐Liss, Inc.
Receiver‐oriented load‐balancing and reliable routing in wireless sensor networks
Authors: Chen Min , Leung Victor C. M. , Mao Shiwen , Kwon Taekyoung 
Published: September 2007

AbstractRouting protocols in wireless sensor networks (WSNs) typically employ a transmitter‐oriented approach in which the next hop node is selected based on neighbor or network information. This approach incurs a large overhead when the accurate neighbor information is needed for efficient and reliable routing. In this paper, a novel receiver‐oriented load‐balancing and reliable routing (RLRR) protocol is proposed. In RLRR, an intermediate node solicits next hop candidates, each of which is to respond with its own backoff time dubbed a temporal gradient (TG). In this way, the next hop is selected without any central coordination on a packet‐by‐packet basis. Thus, each node needs not maintain any neighbor information. The remaining energy level used to determine the TG is always accurate and up‐to‐date. Furthermore, neighbor nodes whose hop count is less than the soliciting node participate in the next‐hop selection process with loop‐free operation guarantee. Comprehensive simulations are carried out to show that RLRR achieves relatively longer network lifetime and higher reliability than other existing schemes. Copyright © 2007 John Wiley & Sons, Ltd.
Determination of Oil Content and Fatty Acid Composition of Sesame Mutants Suited for Intensive Management Conditions
Authors: Arslan Çiğdem , Uzun Bülent , Ülger Salih , İlhan Çağırgan M. 
Published: September 2007

AbstractSesame mutants with closed capsules, determinate growth habit and wilt resistance, have been proposed to be suitable for intensive management conditions facilitating mechanized harvesting. The objective of our experiment was to determine the oil content and fatty acid composition of these mutants before they are placed on the market. Oil content and fatty acids were studied in 19 mutants, 6 breeding lines and 4 control source genotypes. The oil contents of the seeds ranged from 46.4 to 62.7%. The mutants had generally a lower oil content than the control genotypes except the wilting tolerant group. For unsaturated fatty acids, oleic acid was higher in the mutants and breeding lines while linoleic acid was lower in the seed oil. However, no mutants or breeding lines were found with radically different composition or with any undesirable lipid component. The closed capsule and determinate growth habit mutants need to be improved for oil content while their fatty acid composition is fine.
Nonlinear Schrödinger equation with a point defect
Authors: Fukuizumi Reika , Ohta Masahito , Ozawa Tohru 
Published: September 2007

We study the nonlinear Schrödinger equation with a delta-function impurity in one space dimension. Local well-posedness is verified for the Cauchy problem in

H^{1}(\mathbb{R})

. In case of attractive delta-function, orbital stability and instability of the ground state is proved in

H^{1}(\mathbb{R})

.

Résumé

On étudie l'équation de Schrödinger non linéaire avec une impureté delta de Dirac en dimension 1. On vérifie que le problème de Cauchy est localement bien posé dans

H^{1}(\mathbb{R})

. Dans le cas de delta de Dirac attractif, la stabilité et l'instabilité orbitale des ondes stationnaires sont vérifiées dans

H^{1}(\mathbb{R})

.
On the Dirac delta as initial condition for nonlinear Schrödinger equations
Authors: Banica V. , Vega L. 
Published: September 2007

In this article we will study the initial value problem for some Schrödinger equations with Dirac-like initial data and therefore with infinite

L^{2}

mass, obtaining positive results for subcritical nonlinearities. In the critical case and in one dimension we prove that after some renormalization the corresponding solution has finite energy. This allows us to conclude a stability result in the defocusing setting. These problems are related to the existence of a singular dynamics for Schrödinger maps through the so-called Hasimoto transformation.

Résumé

Dans cet article on étudie le problème de Cauchy pour des équations de Schrödinger avec donnée initiale de type Dirac et donc avec masse

L^{2}

infinie, obtenant des résultats positifs pour les non linéarités sous-critiques. Dans le cas critique et en dimension un, on montre qu'après une certaine renormalisation la solution correspondante est d'énergie finie. On en déduit un résultat de stabilité dans le cas défocalisant. Ces problèmes sont liés à l'existence d'une dynamique singulière des applications de type Schrödinger par la transformation de Hasimoto.
Subcellular distribution of spermidine/spermine N1‐acetyltransferase
Authors: Holst C. Martina , Nevsten Pernilla , Johansson Fredrik , Carlemalm Eric , Oredsson Stina M. 
Published: September 2007

AbstractThe subcellular distribution of the polyamine catabolic enzyme spermidine/spermine N1‐acetyltransferase (SSAT) was studied in L56Br‐C1 cells treated with 10 μM N1,N11‐diethylnorspermine (DENSPM) for 24 h. Cells were fractioned into three subcellular fractions. A particulate fraction containing the mitochondria was denoted as the mitochondrial fraction. After DENSPM treatment, an increase in SSAT activity was mainly found in the mitochondrial fraction. Western blot analysis showed an increased level of the SSAT protein in the mitochondrial fraction compared to the cytosolic fraction. Immunofluorescence microscopy and immunogold labeling transmission electron microscopy also showed a mitochondrial association of SSAT. Transmission electron microscopy revealed that the endoplasmic reticulum was devoid of ribosomes in DENSPM‐treated cells, in contrast to control cells that contained ample ribosomes. An increased SSAT activity in connection with the mitochondria may be part of the mechanism of DENSPM‐induced apoptosis.