bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combinatorial optimization problems in the analysis and design of probabilistic networks
Authors: Bauer D. , Boesch F. , Suffel C. , Tindell R. 
Published: May 2007

AbstractThis paper presents some results regarding the design of reliable networks. The problem under consideration involves networks which are undirected graphs having equal and independent edge failure probabilities. The index of reliability is the probability that the network fails (becomes disconnected). For “small” edge failure probabilities and given p and q there exists a class of p vertex, q edge graphs with the property that any graph in the class has a smaller probability of disconnection than any graph outside of the class. We solve the problem of synthesizing graphs in this class.
The minimum augmentation of a directed tree to a k‐edge‐connected directed graph
Authors: Kajitani Yoji , Ueno Shuichi 
Published: May 2007

AbstractFor a directed graph G, let d+(ν) and d (ν) be the outdegree and indegree of vertex ν, respectively. Given a positive integer k, the outdeficiency and indeficiency are defined by δ (ν) = max (k − d+ (ν), 0) and δ (ν) = max(k − d− (ν), 0), respectively. It is evident that in augmenting G to a k‐edge‐connected directed graph, at least δk(G) = max(Σδ (ν), Σδ (ν)) edges are necessary. This paper proves the theorem that if G is a directed tree (directed graph whose underlying graph is a tree) this number of edges is enough. The proof is made by presenting a construction procedure of polynomial‐order complexity.
Shortest paths in networks with exponentially distributed arc lengths
Authors: Kulkarni V. G. 
Published: May 2007

AbstractThis paper develops methods for the exact computation of the distribution of the length of the shortest path from a given source node s to a given sink node t in a directed network in which the arc lengths are independent and exponentially distributed random variables. A continuous time Markov chain with a single absorbing state is constructed from the original network such that the time until absorption into this absorbing state starting from the initial state is equal to the length of the shortest path in the original network. It is shown that the state space of this Markov chain is the set of all minimal (s, t) cuts in the network and that its generator matrix is upper triangular. Algorithms are described for computing the distribution and moments of the length of the shortest path based on this Markov chain representation. Algorithms are also developed for computing the probability that a given (s, t) path is the shortest path in the network and for computing the conditional distribution of the length of a path given that it is the shortest (s, t) path in the network. All algorithms are numerically stable and are illustrated by several numerical examples.
Linear arboricity of digraphs
Authors: Nakayama A. , Peroche B. 
Published: May 2007

AbstractA linear diforest is a digraph whose connected components are paths. We define the linear arboricity of a digraph, denoted la(G), as the minimum number of linear diforests which partition the arcs of G. In this paper, we prove that the determination of la(G) is NP‐complete. We prove also that the problem becomes polynomial for acyclic digraphs. Finally, we give the value of la(G) for several families of digraphs, in particular 2‐regular digraphs.
An efficient implementation of the “partan” variant of the linear approximation method for the network equilibrium problem
Authors: Florian Michael , Guálat Jacques , Spiess Heinz 
Published: May 2007

AbstractThe PARTAN variant of the linear approximation method is adapted for solving the network equilibrium problem. A simple and efficient algorithm is stated. Its properties are analyzed by using algebraic and geometric approaches. Its computational efficiency on small and large scale problems is compared to that of the linear approximation method.
Some generalizations of the steiner problem in graphs
Authors: Duin C. W. , Volgenant A. 
Published: May 2007

AbstractThe Steiner Problem in Graphs (SP) is the problem of finding a set of edges with minimum total weight which connects a given subset of nodes in an edge‐weighted (undirected) graph. In the more general Node‐weighted Steiner Problem (NSP) also node weights are considered. A restricted minimum spanning tree model is adjusted for the NSP as well as for the Steiner Forest Problem, a newly introduced generalization. The NSP is related to the Directed Steiner Problem. Reduction tests for the SP, reducing the size of the problem graph, are adapted for these generalizations and some new tests are developed.
Generalizations of broadcasting and gossiping
Authors: Richards Dana , Liestman Arthur L. 
Published: May 2007

AbstractThree generalizations of broadcasting and gossiping are considered: conference broadcasting in which broadcasting is done by conference calls, partial gossiping in which every gossip must learn at least k pieces of information, and set to set gossiping in which one subset of the members must learn all of the messages of another subset of the members.
Computational complexity of PERT problems
Authors: Hagstrom Jane N. 
Published: May 2007

AbstractComputational complexity results for two PERT problems are presented. A project is specified by precedence relations among tasks. Task durations are independent random variables with discrete, finite ranges. The following results are obtained: (1) computing a value of the cumulative distribution function of project duration is #P‐complete, (2) computing the mean of the distribution is at least as hard, and (3) neither of the problems in (1) and (2) can be computed in time polynomial in the number of points in the range of the project duration unless P = NP.
Stochastic shortest paths with recourse
Authors: Andreatta Giovanni , Romeo Luciano 
Published: May 2007

AbstractThis paper considers Stochastic Shortest Path (SSP) problems in probabilistic networks. A variety of approaches have already been proposed in the literature. However, unlike in the deterministic case, they are related to distinct models, interpretations and applications. We have chosen to look at the case where detours from the original path must be taken whenever the “first‐choice” arc fails. The main results obtained include the proof of some counterintuitive facts (e.g., the SSP may contain a cycle), the proof of the validity of applying stochastic programming to this problem and the proof that the computational complexity of a particular SSP problem is polynomial.
Antiapoptotic effect of found in inflammatory zone (FIZZ)1 on mouse lung fibroblasts
Authors: Chung MJ , Liu T , Ullenbruch M , Phan SH 
Published: May 2007

AbstractMyofibroblasts play an essential role in the abnormal deposition of extracellular matrix in pulmonary fibrosis. The presence or prolonged survival of these cells may be a key factor in the pathogenesis of progressive pulmonary fibrosis. Found in inflammatory zone (FIZZ)1 can induce myofibroblast differentiation and has an antiapoptotic effect on embryonic lung explant cultures. In this study, we investigated whether FIZZ1 also has an antiapoptotic effect on mouse lung fibroblasts (MLFs). Cells were treated with FIZZ1 for 24 h and then apoptosis was induced by TNFα in the presence of cycloheximide (CHX). FIZZ1 exhibited an antiapoptotic effect in MLFs, as assessed by flow cytometric analysis and TUNEL staining. Moreover, the cell number was higher in the FIZZ1‐treated group relative to the non‐treated control group after treatment with TNFα and CHX. FIZZ1 treatment also inhibited the apoptotic agent‐induced activities of caspase‐3 and caspase‐8. Examination of potential signalling pathways revealed that FIZZ1 induced rapid phosphorylation of ERK‐1/2, while PD98059, a MEK/ERK inhibitor, markedly induced activation of caspase‐3. This anti‐apoptotic effect of FIZZ1 was associated with induction of myofibroblast differentiation in response to FIZZ1 stimulation. Taken together, these findings suggest that FIZZ1 is involved in pulmonary fibrosis through both induction of myofibroblast differentiation and increased or prolonged survival of myofibroblasts. This effect of FIZZ1 was mediated by inhibition of caspase‐3 and ‐8, with involvement of the ERK pathway. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Synthesis and characterization of poly (hydroxyether ketone) and its copolymers
Authors: Yang Xingtian , Zheng Sixun 
Published: May 2007

AbstractA novel semi‐crystalline polyhydroxyether, poly(hydroxyether ketone) (PHEK), was synthesized via the direct polycondensation between 4,4‐dihydroxybenzophenone and epichlorohydrin. By means of Fourier transform infrared and NMR spectroscopy and gel permeation chromatography (GPC), the structure of PHEK was characterized. Differential scanning calorimetry (DSC) and wide‐angle X‐ray diffraction (WAXRD) show that PHEK is a semi‐crystalline polymer with a high rate of crystallization. The polymer possesses a glass transition temperature of 109 °C and a melting temperature of 239 °C. When 4,4′‐isopropylidenediphenol was used as a second bisphenol and was added to copolymerize with a stoichiometric amount of epichlorohydin, a series of polyhydroxyether copolymers were obtained. The copolymers with various compositions were characterized by means of NMR, GPC, WAXRD and DSC. It was found that the crystallinity of the copolymers dramatically decreased with increasing content of 4,4′‐isopropylidenediphenol. The glass transition temperatures of the copolymers are intermediate between those of PHEK and the poly(hydroxyether of bisphenol A) and decreased with increasing content of 4,4′‐isopropylidenediphenol. Copyright © 2007 Society of Chemical Industry
Automated serum peptide profiling using novel magnetic C18 beads off‐line coupled to MALDI‐TOF‐MS
Authors: Jimenez Connie R. , El Filali Zineb , Knol Jaco C. , Hoekman Klaas , Kruyt Frank A. E. , Giaccone Giuseppe , Smit August B. , Li Ka Wan 
Published: May 2007

AbstractSerum peptide profiling by MS is an emerging approach for disease diagnosis and biomarker discovery. A magnetic bead‐based method for off‐line serum peptide capture coupled to MALDI‐TOF‐MS has been recently introduced. However, the reagents are not available to the general scientific community. Here, we developed a protocol for serum peptide capture using novel magnetic C18 beads, and automated the procedure on a high‐throughput magnetic particle processor. We investigated bead equilibration, peptide binding and peptide elution conditions. The method is evaluated in terms of peaks counts and reproducibility of ion intensities in control serum. Overall, the DynaBead‐RPC18‐based serum sample processing protocol reported here is reproducible, robust and allows for the detection of ˜200 peptides at m/z 800–4000 of serum that was allowed to clot for 1 h. The average intra‐experiment %CV of normalized ion intensities for crude serum and 0.5% TFA/0.15% n‐octyl glucoside‐treated serum, respectively, were 12% (range 2–38%) and 10% (3–21%) and the inter‐experiment %CVs were 24% (10–53%) and 31% (10–59%). Importantly, this method can be used for serum peptide profiling by anyone in possession of a MALDI‐TOF instrument. In conjunction with the KingFisher® 96, the whole serum peptide capture procedure is high‐throughput (˜20 min per isolation of 96 samples in parallel), thereby facilitating large‐scale disease profiling studies.
Stable non‐supersymmetric vacua at the bottom of cascading gauge theories
Authors: Argurio R. , Bertolini M. , Closset C. , Cremonesi S. 
Published: May 2007

AbstractWe consider a wide class of cascading gauge theories which usually lead to runaway behavior in the IR, and discuss possible deformations of the superpotential at the bottom of the cascade which stabilize the runaway direction and provide stable non‐supersymmetric vacua. The models we find may allow for a dual weakly coupled supergravity analysis of dynamical supersymmetric breaking.
Weyl‐invariant lightlike branes and soldering of black hole space‐times
Authors: Guendelman E.I. , Kaganovich A. , Nissimov E. , Pacheva S. 
Published: May 2007

AbstractWe consider self‐consistent coupling of the recently introduced new class of Weyl‐conformally invariant lightlike branes (WILL‐branes) to D = 4 Einstein‐Maxwell system plus a D = 4 three‐index antisymmetric tensor gauge field. We find static spherically‐symmetric solutions where the space‐time consists of two regions with different black‐hole‐type geometries and different values for a dynamically generated cosmological constant, separated by the WILL‐brane which “straddles” their common event horizon. Furthermore, the WILL‐brane produces a potential “well” around itself acting as a trap for test particles falling towards the horizon.
Microstates and near‐horizon D‐brane probes
Authors: Raeymaekers J. 
Published: May 2007

AbstractIn [1], Gaiotto, Strominger and Yin proposed a novel way of counting black hole microstates by counting the quantum mechanical ground states of probe branes placed in the near‐horizon black hole background. We discuss the generalization of this proposal to the case of two‐charge D0‐D4 ‘small’ black holes in type IIA. We also describe the construction of BPS D‐brane probes in the near‐horizon region of the 2‐charge D1‐D5 system in type IIB.
On meta‐stable SQCD with adjoint matter and gauge mediation
Authors: Amariti A. , Girardello L. , Mariotti A. 
Published: May 2007

AbstractWe briefly review our analysis of a model with non supersymmetric vacua in 𝒩 = 1 gauge theories with adjoint matter and no R‐symmetry. We show here that this model without any modification fits into a direct gauge mediation scenario and leads to massive gauginos.
Adding D7‐branes to the Polchinski‐Strassler gravity background
Authors: Apreda R. , Erdmenger J. , Lüst D. , Sieg C. 
Published: May 2007

AbstractWe motivate and summarize our analysis of hep‐th/0610276 in which we consider D7‐brane probe embeddings in the Polchinski‐Strassler background with 𝒩 = 2 supersymmetry. The corresponding dual gauge theory is given by the 𝒩 = 2* theory with fundamental matter. Based on a talk given by C. Sieg at the RTN Workshop 2006, Napoli.
Consistent de Sitter string vacua from Kähler stabilization and D‐term uplifting
Authors: Parameswaran S.L. , Westphal A. 
Published: May 2007

AbstractIn this note, we review our construction of de Sitter vacua in type IIB flux compactifications, in which moduli stabilization and D‐term uplifting can be combined consistently with the supergravity constraints. Here, the closed string fluxes fix the dilaton and the complex structure moduli while perturbative quantum corrections to the Kähler potential stabilize the volume Kähler modulus in an AdS4‐vacuum. Then, magnetized D7‐branes provide consistent supersymmetric D‐term uplifting towards dS4. Based on hep‐th/0602253.
High giant magnetoresistance in electrodeposited Cu/Co nano‐multilayers
Authors: Gupta Priyanka , Pandya Dinesh K. , Kashyap Subhash C. , Chaudhary Sujeet 
Published: May 2007

AbstractNano‐multilayers of Cu(6 nm)/Co(∼22 nm) have been electrodeposited in potentiostatic pulse mode on ITO coated glass substrates. Cyclic voltammetry and chronoamperometric studies were performed to determine the potential and duration for the deposition of individual layers. A 50‐bilayer stack exhibited a room temperature GMR of 12.5%, at 8 kOe. Even at low fields of ∼3 kOe, this multilayer exhibited ∼10% GMR, thereby demonstrating the potential application of electrodeposition (ED) process in achieving appreciable value of GMR at room temperature and at lower field values. The observed high value of GMR at room temperature may be attributed to the antiferromagnetically (AF) aligned magnetic layers in the absence of magnetic field. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Integration of enhancement and depletion‐mode AlGaN/GaN MIS‐HFETs by fluoride‐based plasma treatment
Authors: Wang Ruonan , Cai Yong , Tang Wilson C. W. , Lau Kei May , Chen Kevin J. 
Published: May 2007

AbstractEnhancement‐mode AlGaN/GaN metal–insulator–semiconductor HFETs (MIS‐HFETs) are demonstrated by combining CF4 plasma treatment technique and a two‐step Si3N4 deposition process. The threshold voltage has been shifted from –4 to 2 V using this technique. A 15 nm Si3N4 layer is inserted under the gate to provide additional isolation between the gate metal and AlGaN surface, which can lead to higher gate turn‐on voltage. The two‐step Si3N4 deposition process is developed to reduce the gate coupling capacitances in the source and drain access regions, while assuring the plasma‐treated gate region being fully covered by the gate electrode. The forward gate turn‐on voltage can be as large as 6.8 V. By tuning the plasma treatment parameters, the threshold voltage of the enhancement‐mode MIS‐HFETs can be raised to as high as 4.3 V. By integrating with depletion‐mode MIS‐HFETs, a direct‐coupled FET logic inverter has been fabricated, with logic low and high noise margins of 2.1 and 2 V. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of millimeter‐wave GaN HFET technology
Authors: Higashiwaki M. , Mimura T. , Matsui T. 
Published: May 2007

AbstractThis paper describes approaches that we have used to improve the high‐frequency device characteristics of GaN‐based heterostructure field‐effect transistors (HFETs). We developed three novel techniques to suppress short‐channel effects: high‐Al‐composition and thin barrier layers, SiN passivation by catalytic chemical vapor deposition, and sub‐100‐nm Ti‐based gates. These techniques were used to enhance the high‐frequency device characteristics of Al0.4Ga0.6N/GaN HFETs, which had a record current‐gain cutoff frequency of 181 GHz. In addition, high‐performance depletion‐ and enhancement‐mode AlN/GaN HFETs, which had DC and RF device characteristics fully comparable with those of state‐of‐the‐art AlGaN/GaN HFETs, were also fabricated with these techniques. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐fmax GaN HEMT with high breakdown voltage over 100 V for millimeter‐wave applications
Authors: Makiyama Kozo , Ohki Toshihiro , Kanamura Masahito , Imanishi Kenji , Hara Naoki , Kikkawa Toshihide 
Published: May 2007

AbstractThis paper discusses the technology of state‐of‐the‐art GaN high electron mobility transistors (GaN‐HEMTs) used for millimeter‐wave amplifiers. A high maximum frequency of oscillation (fmax) device with high breakdown voltage (BVgd) was focused on to improve the gain and efficiency of a millimeter‐wave amplifier. In this study, we demonstrated a high fmax of 210 GHz with a BVgd of over 100 V using a novel Y‐shaped Schottky‐gate and GaN‐cap structure, for the first time. The effect of the AlGaN layer and the device dimensions were investigated to obtain a highly reliable millimeter‐wave power amplifier. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AlGaN/GaN high electron mobility transistor sensor sensitive to ammonium ions
Authors: Alifragis Y. , Volosirakis A. , Chaniotakis N. A. , Konstantinidis G. , Iliopoulos E. , Georgakilas A. 
Published: May 2007

AbstractChemically modified Field Effect Transistor (ChemFET) sensor for ammonium (NH$ ^+_4 $) ions was developed from AlGaN/GaN High Electron Mobility Transistor (HEMT) structures (NH$ ^+_4 $‐ChemHEMT). The sensor consists of a HEMT device with non‐metallized gate, which was coated with a polyvinyl chloride (PVC) membrane enriched with ammonium ionophore (Nonactin). The AlGaN/GaN NH$ ^+_4 $‐ChemHEMT with gate width of 100 μm and gate length of 100 μm exhibited a constant sensitivity of 55.5 mV/pNH$ ^+_4 $ for NH$ ^+_4 $ concentration in the range from 10–5 M to 10–2 M. The NH$ ^+_4 $ concentration detection limit was 5.4 × 10–6 M, which is approximately one order of magnitude lower compared to Si based insulator gate ChemFETs. The sensor exhibited also sufficiently long storage lifetime, indicating the strong adhesion of the PVC membrane to the GaN(0001) surface. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental demonstration of enhancement mode GaN MOSFETs
Authors: Huang W. , Chow T. P. , Khan T. 
Published: May 2007

AbstractWe report on the demonstration of enhancement‐mode n‐channel GaN high‐voltage metal–oxide field‐effect transistor (MOSFET) realized on both p‐ and n‐GaN epilayer on sapphire substrates. These MOSFETs, with different gate geometries, shows good DC characteristics with world‐best field‐effect mobility of 167 cm2/V s and maximum blocking voltage of 940 V. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theory of quantum transport in carbon nanotubes: Perfect conductance, dynamical conductivity, and inter‐wall interaction
Authors: Ando Tsuneya , Asada Yoichi , Uryu Seiji 
Published: May 2007

AbstractA brief review is given on transport properties of carbon nanotubes mainly from a theoretical point of view. The topics include an effective‐mass description of electronic states, the absence of backward scattering except for scatterers with a potential range smaller than the lattice constant, the presence of a perfectly conducting channel, and effects of symmetry breaking perturbations. The dynamical conductivity in the presence of a perfect channel and inter‐wall interactions in double‐wall nanotubes are also discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light‐induced cytotoxicity of 16 polycyclic aromatic hydrocarbons on the US EPA priority pollutant list in human skin HaCaT keratinocytes: Relationship between phototoxicity and excited state properties
Authors: Wang Shuguang , Sheng Yinghong , Feng Manliang , Leszczynski Jerzy , Wang Lei , Tachikawa Hiroyasu , Yu Hongtao 
Published: May 2007

AbstractThe photocytotoxicity of 16 polycyclic aromatic hydrocarbons (PAHs) on the priority pollutant list of the United States Environmental Protection Agency (US EPA) were tested in human skin HaCaT keratinocytes. A selected PAH was mixed with HaCaT cells and irradiated with a solar simulator lamp for a dose equivalent to 5 min of outdoor sunlight and the cell viability was determined immediately and also after 24 h of incubation. For the cells without incubation after the treatments, it is found that all PAHs with three rings or less, except anthracene, are not photocytotoxic, while the four or five‐ring PAHs (except chrysene), benz[a]anthracene, dibenzo[a,h]anthracene, benzo[ghi]perylene, benzo[a]pyrene, indeno[1,2,3‐cd]pyrene, benzo[b]fluorenthene, fluorenthene, and pyrene, are photocytotoxic to the human skin HaCaT keratinocytes. If the cells were incubated for 24 h after the treatments, the photocytotoxic effect of the PAHs was greatly amplified in comparison to the nonincubated cells. For the 24 h incubated cells, all PAHs except naphthalene exhibit photocytotoxicity to some extent. Exposure to 5 μM of the 4‐ and 5‐ring PAHs (except chrysene) and 3‐ring anthracene more than 80% of the cells lose viability. The photocytotoxicity of the PAHs correlates well with several of their excited state properties: light absorption, excited singlet‐state energy, excited triplet‐state energy, and HOMO‐LUMO energy gap. All the photocytotoxic PAHs absorb light at >300 nm, in the solar UVB and UVA region. There is a threshold for each of the three excited state descriptors of a photocytotoxic PAH: singlet energy <355 kJ/mol (corresponding to 337 nm light), triplet energy <230 kJ/mol (corresponding to 520 nm light), HOMO‐LUMO gap <3.6 eV (corresponding to 344 nm light) obtained at the Density Functional Theory B3LYP/6‐31G(d) level. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 318–327, 2007.