bluuebunny/crossref_metadata_2025 huggingface dataset:
ON THE OPTIMAL DRIVERS OF HIGH-SPEED LOW POWER ICs
Authors: ZHOU D. , LIU X. Y.
Published: October 2004

In this paper we study the optimal design of drivers for high-performance VLSI systems. Specifically, we design a driver for a given interconnect such that the signal delay is minimal, or a driver such that the power dissipation and chip area are minimal for a specified delay. For a driver consisting of the cascaded inverters, we first show that the well known method using a fixed size-ratio e (=2.73) between consecutive inverters does not give the optimal design due to the over-simplified circuit model used. Based on the transistor's nonlinear I-V characteristics, we derive an analytic relationship among the parameters of signal delay, power dissipation, driver size, and interconnection load. Using this relationship, we obtain the optimal design of drivers for high-speed low power ICs. When driving a heavy load, the newly designed drivers can reduce the delay by up to 15%, and the power dissipation and chip area by up to one order as compared to the best known designs. The developed optimal driver has a significant impact on the design of high-performance ICs, such as the high-speed bus in microprocessors, interconnect circuit in MCMs, minimal delay clock network, buffers for sending signals from chip to packaging pads, and low power circuits. The practical design examples are given in the paper.
A HIGH PERFORMANCE PARALLEL STRASSEN IMPLEMENTATION
Authors: GRAYSON BRIAN , VAN DE GEIJN ROBERT
Published: October 2004

In this paper, we give a practical high performance parallel implementation of Strassen’s algorithm for matrix multiplication. We show how under restricted conditions, this algorithm can be implemented plug compatible with standard parallel matrix multiplication algorithms. Results obtained on a large Intel Paragon system show a 10– 20% reduction in execution time compared to what we believe to be the fastest standard parallel matrix multiplication implementation available at this time.
OPTIMAL PARALLEL CONSTRUCTION OF MINIMAL SUFFIX AND FACTOR AUTOMATA
Authors: BRESLAUER DANY , HARIHARAN RAMESH
Published: October 2004

This paper gives optimal parallel algorithms for the construction of the smallest deterministic finite automata recognizing all the suffixes and the factors of a string. The algorithms use recently discovered optimal parallel suffix tree construction algorithms together with data structures for the efficient manipulation of trees, exploiting the well known relation between suffix and factor automata and suffix trees.
LOW CROSSTALK ADDRESS ENCODINGS FOR OPTICAL MESSAGE SWITCHING SYSTEMS
Authors: BEN-ASHER YOSI , SCHUSTER ASSAF
Published: October 2004

An optical message switching system delivers messages from N sources to N destinations using beams of light. The redirection of the beams involves vector-matrix multiplication and a threshold operation. The input vectors are set by the sources and may be viewed as the addresses of the desired destinations. In a massively parallel system, it is highly desirable to reduce the number of threshold (non-linear) elements, which require extra wiring and increase clock skew. Moreover, the threshold devices have a sensitivity parameter (implied by the technology) defined as the gap in which the outcome of the device is not determined. This gap is largely effected by the crosstalk which is the maximum number of joint set bits in any pair of addresses, implying a lower bound on the maximum intensity for which the outcome of the threshold operation is determined.

In this work we consider the design of addresses which are both short (so that the number of threshold devices is reduced) and have low crosstalk (so that the sensitivity gap may grow). We show that addresses of O( log N) bits exist, for which the crosstalk is a constant fraction of the number of set bits in each address, hence allowing for a Θ( log N) sized sensitivity gap. More generally, we show the precise coefficient which depends on the desired gap. It is established that when using O( log N) bit addresses, the crosstalk cannot be further reduced. An exact construction of O( log 2 N) bit addresses is given, where the involved constant depends on the desired crosstalk. Finally we describe briefly the basic optical elements that can be used in order to construct a message switching system which use these address schemes.
A LOWER BOUND ON THE AVERAGE PHYSICAL LENGTH OF EDGES IN THE PHYSICAL REALIZATION OF GRAPHS
Authors: KOPPELMAN DAVID M.
Published: October 2004

The stereo-realization of a graph is the assignment of positions in Cartesian space to each of its vertices such that vertex density is bounded. A bound is derived on the average edge length in such a realization. It is similar to an earlier reported result, however the new bound can be applied to graphs for which the earlier result is not well suited. A more precise realization definition is also presented. The bound is applied to d-dimensional realizations of de Bruijn graphs, yielding an edge length of Ω((1−2−d)rn/d/(2n)), where r is the radix (number of distinct symbols) and n is the number of graph dimensions (number of symbol positions). The bound is also applied to shuffle-exchange graphs; for such graphs with small radix the edge-length bound is [Formula: see text], where r is the radix, n is the number of graph dimensions, lσ is the average length of shuffle edges, and lε is the average length of exchange edges.
A CLASS OF SYSTOLIC TRIDIAGONAL LINEAR SOLVERS
Authors: BEKAKOS M.P. , EFREMIDES O.B.
Published: October 2004

Herein, the Concurrent Backward and Forward (B&F) complete solution approach and the Main Diagonal Redirection (MDR) technique are studied, on a comparative basis, for the solution of tridiagonal linear systems on VLSI systolic processor arrays. The architectural design investigated consists of modified <2-in-1> systolic cells. The paper concludes with the generalization of both approaches for multiple pipes arrangement on a 3D Mesh(d) topology.
ON RECURSIVE INTERCONNECTION NETWORKS AND THEIR EXTENSIONS
Authors: FERNANDES RONALD , KANEVSKY ARKADY
Published: October 2004

Properties of the WK-Recursive interconnection network are described and compared with other topologies. The effect of message locality is considered. The network is extended to two other topologies, the first of which extends the network to a third dimension, and the second defines a pyramid-like network structure.
SEQUENTIAL-LIKE PROOFS OF DATA-PARALLEL PROGRAMS
Authors: GUYADEC Y. LE , VIROT B.
Published: October 2004

We define a proof system à la Hoare for a common kernel of existing data-parallel languages. It includes conditioning constructs and non-local control transfers such as data-parallel break and continue. Assertions are usual predicates and manipulations of the extent of parallelism are translated into explicit assignments. Therefore, proofs reuse the classical assertional setting of sequential Hoare Logic.
INCREMENTAL TRANSITIVE DEPENDENCY TRACKING IN DISTRIBUTED COMPUTATIONS
Authors: JARD CLAUDE , JOURDAN GUY-VINCENT
Published: October 2004

The notion of causal dependency between events in distributed systems plays a central role in reasoning about distributed program behaviours [14]. Different techniques have been designed to track these dependencies during execution. We suggest a new incremental transitive dependency tracking technique. Once the transitive dependencies are recorded for an observable event, the dependency tracking cost can be reduced by propagating only future dependencies beyond that event. Furthermore, in contrast with the direct dependency tracking technique already proposed in the literature, our technique allows to compute the dependencies among an arbitrary subset of observable events. This gives an interesting filtering capability.
SUPER ROTATOR: INCREMENTALLY EXTENSIBLE DIRECTED NETWORK GRAPH OF SUBLOGARITHMIC DIAMETER
Authors: SRIMANI PRADIP K.
Published: October 2004

We propose a new family of directed interconnection network graphs for an arbitrary number of nodes. The proposed network graph is almost regular (the difference between the in-degrees and out degrees of nodes is 2, a constant independent of the size of the network), has a diameter sub logarithmic in the number of nodes, is optimally fault tolerant and can be defined for an arbitrary number of nodes.
MARRELLA: A TOOL TO ANALYSE THE GRAPH OF STATES
Authors: AMBROISE DOMINIQUE , ROZOY BRIGITTE
Published: October 2004

Abstract: Traces and partial orders have been used as an approach to reduce time and memory in model-checking for concurrent programs. We show here that we can also make use of event structures and generalized traces: we extend algorithms for partial orders and traces by using event structure to generate reachability graphs; we gain for two reasons: first resulting algorithms are optimal and second a careful implementation spares memory.
IMPROVING THE RELIABILITY OF BODY ASSEMBLY LINE EQUIPMENT
Authors: AMASAKA KAKURO , SAKAI HIROHISA
Published: October 2004

It is necessary to establish higher levels of equipment reliability in a short time, the market demands ever shorter lead times for the release of new models. Also, the demand for new-model cars is very strong immediately after their introduction.

The conventional method for enhancing equipment reliability is by screening alone. However, this requires screening operations on production lines and so has been an obstacle to line production and prevented shortening of lead times.

We are now able to dramatically enhance equipment reliability in a very short time by detecting failure modes and forecasting the number of occurrences using a scientific technique based on reliability engineering.
OPTIMAL INSPECTION ORDER WHEN PROCESS’ FAILURE RATE IS CONSTANT
Authors: HE QI-MING , GERCHAK YIGAL , GROSFELD-NIR ABRAHAM
Published: October 2004

Suppose that a lot has been produced by a process with a constant failure rate. So either the entire lot is good, or all units up to some point are good and from that point on are all defective. We wish to determine the order in which units in such lot should be inspected so as to minimize the expected number of inspections needed to identify all defectives. Unlike previous work in this area, we do not a priori assume that the last unit in the lot is defective, and that key difference turns out to dramatically influence the nature of the optimal inspection policy and the expected number of units inspected. After analyzing the optimal policy, we suggest a very simple and intuitive heuristic, which turns out to perform extremely well. Numerical results are provided.
REVIEW OF FAN LIFE EVALUATION PROCEDURES
Authors: KIM SUNG , VALLARINO CARLOS , CLAASSEN ALAN
Published: October 2004

Improving the reliability of air cooled electronic equipment must include focusing on the life expectancy of the fans or blowers. Evaluating fan failure behavior, however, is not a trivial problem, as vendors report very little information on this subject. Even when product literature provides such data, one vendor’s results are generally impossible to compare with another’s due to different test procedures, different assumptions, and different calculation methods, not all of which are explicitly defined.

This paper is designed to help thermal and component evaluation engineers who have been assigned the task of sorting through these sometimes conflicting, often incompatible, claims regarding fan quality. We start with a definition of fan failure in terms of rotational speed, running current, and acoustic noise. Some basic statistical principles, such as Weibull hazard rate, Mean Time To Failure (MTTF) and L10 life, are presented in the reliability section, leading into methods for the estimation of fan life. Booser’s equation for grease life is included and its limitations for modern greases are noted; the standard equation for bearing rating life is also covered. To verify calculated fan life estimates, a designed experiment may be performed. A basic formula for the design of a fan life experiment is given, together with a brief analysis of published failure data from such an experiment. Most fan life tests are conducted under stress conditions, such as high temperature, that accelerate fan failures. The final section discusses accelerated life testing, including potential pitfalls. Simulating a mini-textbook, the paper contains valuable everyday reference material, including sample calculations to illustrate the concepts reviewed.
SOFTWARE RELIABILITY ESTIMATIONS THROUGH USAGE ANALYSIS OF SPECIFICATIONS AND DESIGNS
Authors: WOHLIN CLAES , WESSLÉN ANDERS , RUNESON PER
Published: October 2004

This paper presents a method proposal for estimation of software reliability before the implementation phase. The method is based upon that a formal specification technique is used and that it is possible to develop a tool performing dynamic analysis, i.e., locating semantic faults in the design. The analysis is performed with both applying a usage profile as input as well as doing a full analysis, i.e., locate all faults that the tool can find. The tool must provide failure data in terms of time since the last failure was detected. The mapping of the dynamic failures to the failures encountered during statistical usage testing and operation is discussed. The method can be applied either on the software specification or as a step in the development process by applying it on the software design. The proposed method allows for software reliability estimations that can be used both as a quality indicator, and for planning and controlling resources, development times, etc. at an early stage in the development of software systems.
PERFORMANCE RELIABILITY OF DS-CDMA MOBILE COMMUNICATION SYSTEM
Authors: SHAHEEN KAMEL M. , GUPTA SOMESHWAR C.
Published: October 2004

Applications of DS-CDMA in mobile communication systems, in forward link and reverse link, imply certain precautions against near–far effect (NFE), multi-access (co-channel) interference (MAI/CCI), and multipath fading. In this paper, two multi-user detection schemes are proposed to enhance the reliability of DS-CDMA system against NFE and MAI for both reverse link and forward link applications. The first scheme, reverse link multistage CCI cancellation (RLCCI) scheme, is derived for a single path channel model and is based on minimization of estimation error between the received signal and its projections on spreading sequences subspace. The second scheme, forward link CCI (FLCCI) cancellation scheme is based on keeping a simple yet robust decoder at the mobile station (MS), reducing the negative impact of CCI, and enhancing CCI positive contributions. FLCCI minimizes the negative impact of CCI by adjusting the magnitudes of vulnerable spreading codes to compensate in advance for CCI losses. Block diagrams, mathematical models, performance analysis and reliability of both cancellation schemes against NFE, MAI, and external noise are discussed in details. The improvements in BER and overall performance are evaluated using Monte Carlo simulation for both schemes.
HIGH-POWER OPTICAL SOURCE USING DYE-DOPED POLYMER OPTICAL FIBER
Authors: YAMAMOTO T. , FUJII K. , TAGAYA A. , NIHEI E. , KOIKE Y. , SASAKI K.
Published: October 2004

Basic characteristics of organic-dye doped polymer optical fibers (DPOFs) are demonstrated. The devices contain laser dye, such as Rhodamine 6G (R6G) and Rhodamine B (RB) in the core region. Firstly, amplification characteristics of DPOF amplifiers (PO-FAs) excited by a pulse-operated, doubled Nd:YAG laser are demonstrated, e.g., a 250 mm-length of RB-POFA gives 1 kW (30 dB) of amplified signal at 591 nm. Next, an all solid state system of RB DPOF laser (POFL) is discussed by numerical simulation and the experimental result of high-power amplified spontaneous emission (ASE) by strong excitation of DPOF is shown.
CdTe:In MONOCRYSTAL MODULES FOR ALL-OPTICAL PROCESSING
Authors: PIETRALUNGA S. , BOFFI P. , MARTINELLI M.
Published: October 2004

The aim of this work is to present the application of photoconductive properties of electro-optical n-doped CdTe:In single crystals to all-optical processing of signals at λ=1550 nm. The mechanism exploits the photogeneration of charge carriers from deep intragap energy levels and their trap-limited drift process under the action of an externally applied cw electric field. An internal space-charge counterfield results that locally shields the electro-optic effect.

Different types of free-space architectural elementary modules in CdTe:In have been implemented. A non-coherent wavelength converter, a switching device, a sampler and a time-to-space converter are presented. The nanosecond regime has been reached.
POLARIZATION DRIVEN POLARIZATION BISTABILITY IN ANISOTROPIC INTERFERENCE FILTERS
Authors: PANAJOTOV K. , TENEV T. , ZARTOV G. , PELT M. , DANCKAERT J. , THIENPONT H. , VERETENNICOFF I.
Published: October 2004

Bandpass interference filters with an anisotropic central layer can be switched by modulating either the incident intensity or the polarization. The behavior of different polarization bistable anisotropic interference filters with and without a heat sink has been investigated experimentally, confirming the existence of polarization driven bistability in an all-optical passive device. The stationary results show good agreement with numerical predictions obtained by coupled thermo-optic multilayer model.
PATTERN FORMATION AND COMPETITION IN NONLINEAR OPTICS
Authors: RESIDORI S. , RAMAZZA P.L. , PAMPALONI E. , ARECCHI F.T.
Published: October 2004

Recently we have observed two-dimensional periodic and quasiperiodic structures in the transverse profile of an optical beam circulating in a feedback loop which contains a nonlinear medium. The symmetries observed depend not only on the interaction between light and nonlinear medium, but also on a nonlocality due to beam rotation in the feedback loop. The linear stability analysis of our model shows the existence of many unstable bands of transverse wavevectors. Close to threshold, predictions are qualitatively and quantitatively confirmed by the experiment. When the intensity threshold values are almost the same for the two principal bands, structures with different wavenumbers arise above threshold. These modes compete with a very complex dynamics. We have started to study this behavior by means of suitable indicators. As a first indicator we have individuated the fraction of light power distributed on the first band respect to that one distributed on both.
NONLINEAR FREQUENCY SUPERPOSITION FOR ROTATING FRAMES
Authors: GISIN BORIS V.
Published: October 2004

In the slowly varying magnitude approximation Maxwell’s equation describing light propagation in some electro-optical crystals under the action of an external electrical field, is equivalent to Pauli’s equation describing motion of particles with spin [Formula: see text] in a mag-netic field. Use of this analogy for measuring the deviation from the linear frequency superposition by transition to rotating frame is discussed. Some group theory aspects of nonlinear law are considered.
A VORTEX-FLAME INTERACTION STUDY USING FOUR-WAVE MIXING TECHNIQUES
Authors: GRISCH F. , ATTAL-TRETOUT B. , BOUCHARDY P. , KATTA V.R. , ROQUEMORE W.M.
Published: October 2004

Temperature and NO concentration can change dramatically during a vortex-flame interaction. In this paper, a vertically mounted buoyant hydrogen-nitrogen jet diffusion flame is used to study vortex-flame interaction. Single shot measurements of temperature by Coherent Anti-Stokes Raman Scattering (CARS) and of NO concentration by Degenerate Four Wave Mixing (DFWM) are used to investigate the temporal and spatial evolution of the flame. The results are compared with theoretical predictions. Temperature and mole fraction are presented in two-dimensional maps. Experimental and theoretical results are in excellent agreement.
THE RAMAN EFFECT AND SOLITONS IN AN ELLIPTICAL OPTICAL FIBER
Authors: MALOMED BORIS A. , TASGAL RICHARD S.
Published: October 2004

We derive a general system of coupled nonlinear Schrödinger equations, describing light in a bimodal optical fiber, taking into account the quasi-instantaneous Raman effect, group-velocity birefringence, phase-velocity birefringence, and optical activity, and for light with general ellipticity. The Raman coefficients prove to obey a relation which depends on the ellipticity.

When group-velocity birefringence and optical activity are both non-zero, polarization couples to the changing frequency, so soliton polarization cannot be held constant in this case. Without optical activity, there are solitons with constant polarization either entirely in one polarization (“simple”) or equally divided between the two polarizations (“vector”). At ellipticity angle 0° to 35.3°, the simple solitons are stable and the vector solitons are unstable, and vice versa for ellipticity angle 35.3° to 90°. With optical activity, the polarization can be constant, but with a rather more complex form. Stability is also examined, and bistability is found in some circumstances.
EIGENVALUE ANALYSIS OF GRADED INDEX NONLINEAR OPTICAL ANTIWAVEGUIDE
Authors: GISIN BORIS V. , HARDY AMOS A.
Published: October 2004

Stability regions of graded index nonlinear optical antiwaveguides are numerically investigated. It is shown that as the antiwaveguide boundary between the core and cladding grows steeper, the structure becomes more effective from the viewpoint of stability of the propagating mode.
0π PULSE SHAPE IN THE SHARP LINE LIMIT CASE
Authors: MATUSOVSKY M. , VAYNBERG B. , ROSENBLUH M.
Published: October 2004

We observe the propagation and the reshaping of low intensity (zero area) 60 fs pulses through high density atomic Cs vapor. The breakup of the pulses is measured for both resonant excitation of the Cs atoms and for laser detunings such that the atomic resonance frequency is in the wings of the pulse spectrum. The theory of 0π pulse propagation, in the extreme sharp-line limit, is extended to include both resonant and off resonant excitation. Good agreement is demonstrated between the observations and the theoretical predictions.
SECOND HARMONIC GENERATION USING A NON BIREFRINGENT MATERIAL IN A DOUBLY RESONANT MONOLITHIC CAVITY
Authors: BERGER V.
Published: October 2004

Doubly resonant second harmonic generation (SHG) in a monolithic cavity is theoretically analysed. Using a non birefringent material as non linear medium, it is shown that both the double resonance condition and the phase matching condition between the two counter propagating second harmonic intracavity waves can be satisfied with a cavity length equal to the coherence length of the non linear process, and with well designed mirror phases. It is also shown theoretically how the double resonance can be maintained with only one tuning parameter. A SHG cavity enhancement of a few tens of thousands may be achieved at double resonance.
ENHANCED FOUR-WAVE MIXING DIFFRACTION EFFICIENCY IN BULK GaAs MICROCAVITIES AT ROOM TEMPERATURE
Authors: BUHLEIER R. , COLLET J.H. , BARDINAL V. , FONTAINE C. , LEGROS R. , HÜBNER M. , KUHL J.
Published: October 2004

We present investigations on Degenerate Four Wave Mixing in bulk GaAs Fabry-Pérot microcavities at room temperature excited with femtosecond pulses. Due to increased interaction length and amplification of light fields in the cavity, the measured diffraction efficiency η≈2×10−3 at 878 nm is enhanced by a factor of roughly 30 compared to bulk GaAs without cavity. The results may be useful for exploiting the cavity enhancement effect for investigation of carrier kinetics at small excitation densities. For application purposes, the results renew the interest in ultrafast coherent deflectors for all-optical routing.
PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES
Authors: FIORINI CÉLINE , NUNZI JEAN-MICHEL , CHARRA FABRICE , SAMUEL IFOR D.W. , ZYSS JOSEPH
Published: October 2004

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.
RELATION BETWEEN QUANTUM AND GEOMETRIC DIMENSIONALITIES IN MOLECULAR NONLINEAR OPTICS: BEYOND THE TWO-LEVEL MODEL FOR ANISOTROPIC SYSTEMS
Authors: BRASSELET S. , ZYSS J.
Published: October 2004

The nonlinear optical susceptibilities of two- or three-dimensional molecular systems exhibit variable anisotropic features depending on their structure and substitution pattern. We show that appropriate geometric (e.g. tensorial) considerations combined with an n-level quantum model (n≥3) are able to account for such nonlinear anisotropy as rigorously defined in an invariant spherical formalism by extension of classical linear anisotropy. We call on two kinds of experiments to investigate these properties: firstly, variation of the incident polarization (VIP) in harmonic light scattering (HLS) experiments is being performed to sort out individual tensorial components of the quadratic hyperpolarizability β tensor; secondly, wavelength dependence studies in coherent second harmonic generation (SHG) from poled thin film media are shown at a preliminary stage to be able to designate those excited states responsible for the nonlinear anisotropy.
A MANY-BODY APPROACH TO DOUBLY RESONANT SUM-FREQUENCY GENERATION INCLUDING QUADRATIC VIBRATIONAL-MODE COUPLINGS
Authors: BOEGLIN A.J. , VALLET J.C. , LAVOINE J.P. , VILLAEYS A.A.
Published: October 2004

A many-body diagrammatic technique has been applied to the time correlator reformulation of doubly resonant infrared-visible sum-frequency generation in molecules. Multimode model calculations show the ability of such an experiment to probe the excited state potential well of adsorbed species. In principle, it is possible to discrimate between linear and quadratic vibronic couplings and to recover these parameters from the data. In presence of very large inhomogeneous broadening of the electronic transition however, the sensitivity to quadratic couplings is being lost while the usefulness of this technique in surface specific vibrational spectroscopy is being preserved.
SIDE CHAIN LIQUID CRYSTAL POLYMERS FOR QUADRATIC NONLINEAR OPTICS
Authors: GONIN D. , GUICHARD B. , LARGE M.C.J. , MORAIS T. DANTAS DE , NOËL C. , KAJZAR F.
Published: October 2004

In this paper we consider the behavior of a number of side chain liquid crystal polymers having the same mesogenic group and relate their liquid crystalline behavior to their polarization and nonlinear optical properties. We show that the liquid crystallinity of the materials results in an enhancement of the polar order over that of isotropic materials, in qualitative agreement with molecular statistical models.
PHOTOINDUCED NONLINEAR EFFECTS IN ORGANIC PHOTOCHROMICS
Authors: DANTSKER D.
Published: October 2004

An analytic expression describing two-wavelength light propagation through an organic photoreversible photochromic Azo and Stilbene-like molecular media characterized by a strong nonoverlapping absorption by the two chromophore isomers has been derived. An analysis of the transmission coefficients for the Trans and Cis modulation modes has shown linear dependence on the pump intensity accompanied by self modulation slope dependence. In addition, the wavelength dependence of the modulation strength and the resulting inverse relationship of the pump intensity as a function of the absorption cross-section has been presented. Large constrast ratios have been obtained for rather low pump and read-out intensities of the order of a hundred microwatts per centimeter square and less. Such optimal working conditions provide a very attractive characteristic for an OASLM based on photoreversible photochromic organic molecular systems.
STIMULATED SCATTERING IN AN OPTICAL LATTICE
Authors: GUIBAL S. , GUIDONI L. , ZACHOROWSKI J. , COURTOIS J.-Y. , VERKERK P. , GRYNBERG G.
Published: October 2004

We present a study of pump-probe spectroscopy experiments in an optical lattice. The probe transmission spectrum contains three types of resonances similar to those found in usual nonlinear media: Raman, Brillouin and Rayleigh resonances. We show evidence of the existence of a propagating elementary excitation in the lattice which involves no interaction between the particles and lead to a Brillouin-like scattering. We discuss the central Rayleigh resonance and show that its shape is sensitive to the radiation pressure.
QUANTUM NOISE REDUCTION IN TRAVELLING-WAVE QUASI-PHASE-MATCHED SECOND HARMONIC GENERATION
Authors: LEVENSON J.A. , VIDAKOVIC P.
Published: October 2004

The present calculation on squeezing capabilities of quadratic nonlinear media in which the phase matching condition is achieved artificially by a periodic poling of the nonlinear susceptibility shows that interesting performance can be obtained for highly integrable and nonlinear materials, using technologies already developed. The origin of squeezing in quasi-phase matched (QPM) media is the cascading of two second order nonlinearities, which at small second harmonic conversion rates has properties similar to a more familiar, purely third order nonlinear effect—Kerr effect.
Heat shock protein 20-mediated force suppression in forskolin-relaxed swine carotid artery
Authors: Meeks Melissa K. , Ripley Marcia L. , Jin Zhicheng , Rembold Christopher M.
Published: October 2004

Increases in cyclic nucleotide levels induce smooth muscle relaxation by deactivation [reductions in myosin regulatory light chain (MRLC) phosphorylation (e.g., by reduced [Ca2+])] or force suppression (reduction in force without reduction in MRLC phosphorylation). Ser16-heat shock protein 20 (HSP20) phosphorylation is the proposed mediator of force suppression. We evaluated three potential hypotheses whereby Ser16-HSP20 phosphorylation could regulate smooth muscle force: 1) a threshold level of HSP20 phosphorylation could inactivate a thin filament as a whole, 2) phosphorylation of a single HSP20 could fully inactivate a small region of a thin filament, or 3) HSP20 phosphorylation could weakly inhibit myosin binding at either the thin- or thick-filament level. We tested these hypotheses by analyzing the dependence of force on Ser16-HSP20 phosphorylation in swine carotid media. First, we determined that swine HSP20 has a second phosphorylation site at Ser157. Ser157-HSP20 phosphorylation values were high and did not change during contractile activation or forskolin-induced relaxation. Forskolin significantly increased Ser16-HSP20 phosphorylation. The relationship between Ser16-HSP20 phosphorylation and force remained linear and was shifted downward in partially activated muscles relaxed with forskolin. Neither forskolin nor nitroglycerin induced actin depolymerization as detected using the F/G-actin ratio method in smooth muscle homogenates. These results suggest that force suppression does not occur in accordance with the first hypothesis (inactivation of a thin filament as a whole). Our data are more consistent with the second and third hypotheses that force suppression is mediated by full or partial inhibition of local myosin binding at the thin- or thick-filament level.
Impaired agonist-dependent myosin phosphorylation and decreased RhoA in rat portal hypertensive mesenteric vasculature
Authors: Zhang Hai-Ying , Shirasawa Yuichi , Chen Xuesong , Yu Hong , Benoit Joseph N.
Published: October 2004

The purpose of the present study was to examine the effects of portal hypertension on agonist-induced myosin phosphorylation and RhoA expression in vascular smooth muscle. A possible link to cAMP-dependent events was also examined. Portal hypertension was produced by stenosis of the portal vein. Vessel segments were treated with or without 50 μM of the PKA inhibitor Rp-cAMPS for 30 min and subsequently stimulated with 10−4M phenylephrine. Myosin regulatory light-chain phosphorylation was detected by immunoblotting. Total RNA from first-order mesenteric arteries and portal veins was isolated and amplified by RT-PCR using RhoA and GAPDH primers. RhoA protein expression was also measured in first-order mesenteric arteries using Western blot analysis. Myosin phosphorylation in maximally stimulated first-order mesenteric arteries was significantly lower in portal hypertensive animals (19.9 ± 2.86%) when compared with sham-operated control (43.8 ± 3.53%). Inhibition of PKA selectively increased myosin phosphorylation to 34.7 ± 4.18%. Rp-cAMPS did not affect the phosphorylation of the portal veins or superior mesenteric arteries. RhoA mRNA and membrane-associated RhoA protein expression in portal hypertensive first-order mesenteric arteries were significantly lower when compared with controls. Acute inhibition of PKA had no effect on RhoA mRNA expression. However, it restored membrane-associated RhoA protein expression in portal hypertensive vessels to control levels. The results suggest that reductions in membrane-associated RhoA expression, which appear to be regulated by cAMP-dependent events, lead to reduced myosin phosphorylation and may underlie the reduced vasoconstrictor effectiveness in the resistance vasculature of portal hypertensive intestine.
Dynamic model for ventricular junctional conductance during the cardiac action potential
Authors: Lin Xianming , Gemel Joanna , Beyer Eric C. , Veenstra Richard D.
Published: October 2004

The ventricular action potential was applied to paired neonatal murine ventricular myocytes in the dual whole cell configuration. During peak action potential voltages >100 mV, junctional conductance ( gj) declined by 50%. This transjunctional voltage ( Vj)-dependent inactivation exhibited two time constants that became progressively faster with increasing Vj. Gjreturned to initial peak values during action potential repolarization and even exceeded peak gjvalues during the final 5% of repolarization. This facilitation of gjwas observed <30 mV during linearly decreasing Vjramps. The same behavior was observed in ensemble averages of individual gap junction channels with unitary conductances of 100 pS or lower. Immunohistochemical fluorescent micrographs and immunoblots detect prominent amounts of connexin (Cx)43 and lesser amounts of Cx40 and Cx45 proteins in cultured ventricular myocytes. The time dependence of the gjcurves and channel conductances are consistent with the properties of predominantly homomeric Cx43 gap junction channels. A mathematical model depicting two inactivation and two recovery phases accurately predicts the ventricular gjcurves at different rates of stimulation and repolarization. Functional differences are apparent between ventricular myocytes and Cx43-transfected N2a cell gap junctions that may result from posttranslational modification. These observations suggest that gap junctions may play a role in the development of conduction block and the genesis and propagation of triggered arrhythmias under conditions of slowed conduction (<10 cm/s).
Signaling for myocardial depression in hemorrhagic shock: roles of Toll-like receptor 4 and p55 TNF-α receptor
Authors: Meng Xianzhong , Ao Lihua , Song Yong , Raeburn Christopher D. , Fullerton David A. , Harken Alden H.
Published: October 2004

Hemorrhagic shock causes myocardial contractile depression. Although this myocardial disorder is associated with increased expression of tumor necrosis factor-α (TNF-α), the role of TNF-α as a myocardial depressant factor in hemorrhagic shock remains to be determined. Moreover, it is unclear which TNF-α receptor mediates the myocardial depressive effects of TNF-α. Toll-like receptor 4 (TLR4) regulates cellular expression of proinflammatory mediators following lipopolysaccharide stimulation and may be involved in the tissue inflammatory response to injury. The contribution of TLR4 signaling to tissue TNF-α response to hemorrhagic shock and TLR4’s role in myocardial depression during hemorrhagic shock are presently unknown. We examined the relationship of TNF-α production to myocardial depression in a mouse model of nonresuscitated hemorrhagic shock, assessed the influence of TLR4 mutation, resulting in defective signaling, on TNF-α production and myocardial depression, and determined the roles of TNF-α and TNF-α receptors in myocardial depression using a gene knockout (KO) approach. Hemorrhagic shock resulted in increased plasma and myocardial TNF-α (4.9- and 4.5-fold, respectively) at 30 min and induced myocardial contractile depression at 4 h. TLR4 mutation abolished the TNF-α response and attenuated myocardial depression (left ventricular developed pressure of 43.0 ± 6.2 mmHg in TLR4 mutant vs. 30.0 ± 3.6 mmHg in wild type, P < 0.05). TNF-α KO also attenuated myocardial depression in hemorrhagic shock, and the p55 receptor KO, but not the p75 receptor KO, mimicked the effect of TNF-α KO. The results suggest that TLR4 plays a novel role in signaling to the TNF-α response during hemorrhagic shock and that TNF-α through the p55 receptor activates a pathway leading to myocardial depression. Thus TLR4 and the p55 TNF-α receptor represent therapeutic targets for preservation of cardiac mechanical function during hemorrhagic shock.
On the economical solution method for a system of linear algebraic equations
Authors: Awrejcewicz Jan , Krysko Vadim A. , Krysko Anton V.
Published: October 2004

The present work proposes a novel optimal and exact method of solving large systems of linear algebraic equations. In the approach under consideration, the solution of a system of algebraic linear equations is found as a point of intersection of hyperplanes, which needs a minimal amount of computer operating storage. Two examples are given. In the first example, the boundary value problem for a three‐dimensional stationary heat transfer equation in a parallelepiped in ℝ3 is considered, where boundary value problems of first, second, or third order, or their combinations, are taken into account. The governing differential equations are reduced to algebraic ones with the help of the finite element and boundary element methods for different meshes applied. The obtained results are compared with known analytical solutions. The second example concerns computation of a nonhomogeneous shallow physically and geometrically nonlinear shell subject to transversal uniformly distributed load. The partial differential equations are reduced to a system of nonlinear algebraic equations with the error of . The linearization process is realized through either Newton method or differentiation with respect to a parameter. In consequence, the relations of the boundary condition variations along the shell side and the conditions for the solution matching are reported.
Peristaltic transport of an Oldroyd‐B fluid in a planar channel
Authors: Hayat T. , Wang Y. , Hutter K. , Asghar S. , Siddiqui A. M.
Published: October 2004

The effects of an Oldroyd‐B fluid on the peristaltic mechanism are examined under the long wavelength assumption. Analytical expressions for the stream function, the axial velocity, and the pressure rise per wavelength are obtained up to the second order in the dimensionless wave number. The effects of the various parameters of interest on the flow are shown and discussed.
2-Chlorohexadecanal Derived From Hypochlorite-Modified High-Density Lipoprotein–Associated Plasmalogen Is a Natural Inhibitor of Endothelial Nitric Oxide Biosynthesis
Authors: Marsche Gunther , Heller Regine , Fauler Günter , Kovacevic Alenka , Nuszkowski Alexander , Graier Wolfgang , Sattler Wolfgang , Malle Ernst
Published: October 2004

Objective—

Myeloperoxidase, a heme enzyme that is present and active in human atherosclerotic lesions, provides a source for the generation of proinflammatory chlorinated reactants contributing to endothelial dysfunction. Modification of high-density lipoprotein (HDL) by hypochlorous acid/hypochlorite (HOCl/Oce
−
)—generated in vivo by the myeloperoxidase-hydrogen peroxide-chloride system of activated phagocytes—forms a proatherogenic lipoprotein particle that binds to and is internalized by endothelial cells.

Methods and Results—

Here we show that HDL, modified with physiologically relevant HOCl concentrations, attenuates the expression and activity of vasculoprotective endothelial nitric oxide synthase. HOCl-HDL promotes dislocalization of endothelial nitric oxide synthase from the plasma membrane and perinuclear location of human umbilical venous endothelial cells. We could identify 2-chlorohexadecanal as the active component mediating this inhibitory activity. This chlorinated fatty aldehyde is formed during HOCl-mediated oxidative cleavage of HDL-associated plasmalogen.

Conclusion—

2-Chlorohexadecanal, produced by the myeloperoxidase-hydrogen peroxide-chloride system of activated phagocytes may act as a mediator of vascular injury associated with ischemia-reperfusion injury, glomerulosclerosis, and atherosclerosis.
Granulocyte Macrophage–Colony Stimulating Factor Increases the Expression of Histamine and Histamine Receptors in Monocytes/Macrophages in Relation to Arteriosclerosis
Authors: Murata Yoshitaka , Tanimoto Akihide , Wang Ke-Yong , Tsutsui Masato , Sasaguri Yasuyuki , De Corte Filip , Matsushita Hiroshi
Published: October 2004

Objective—

To study the effect of granulocyte macrophage–colony-stimulating factor (GM-CSF) on histamine metabolism in arteriosclerosis, the expression of histidine decarboxylase (HDC; histamine-producing enzyme), histamine receptors 1 and 2 (HH1R and HH2R), and GM-CSF was investigated in human and mouse arteriosclerotic carotid arteries. Furthermore, the molecular mechanisms of GM-CSF–induced HDC and HH1R expression in monocytic U937 cells were investigated.

Methods and Results—

Immunohistochemistry showed that atherosclerotic human coronary and mouse ligated carotid arteries contained HDC-expressing macrophages. Gene expression of HDC, HH1R, HH2R, and GM-CSF was also detected in the lesions. In U937 cells, GM-CSF enhanced histamine secretion and gene expression of HDC and HH1R. A promoter assay showed that GM-CSF enhanced gene transcription of HDC and HH1R but not HH2R.

Conclusion—

The present results indicate that HDC and HHR are expressed in arteriosclerotic lesion, and that GM-CSF induces HDC and HH1R expression in monocytes. Locally produced histamine might participate in atherogenesis by affecting the expression of atherosclerosis-related genes in monocytes and smooth muscle cells.
Antiangiogenic Activity of Semisynthetic Biotechnological Heparins
Authors: Presta Marco , Oreste Pasqua , Zoppetti Giorgio , Belleri Mirella , Tanghetti Elena , Leali Daria , Urbinati Chiara , Bugatti Antonella , Ronca Roberto , Nicoli Stefania , Moroni Emanuela , Stabile Helena , Camozzi Maura , Hernandez German Andrés , Mitola Stefania , Dell’Era Patrizia , Rusnati Marco , Ribatti Domenico
Published: October 2004

Objective—

Low-molecular-weight heparin (LMWH) exerts antitumor activity in clinical trials. The K5 polysaccharide from
Escherichia coli
has the same structure as the heparin precursor. Chemical and enzymatic modifications of K5 polysaccharide lead to the production of biotechnological heparin-like compounds. We investigated the fibroblast growth factor-2 (FGF2) antagonist and antiangiogenic activity of a series of LMW
N
,
O
-sulfated K5 derivatives.

Methods and Results—

Surface plasmon resonance analysis showed that LMW-K5 derivatives bind FGF2, thus inhibiting its interaction with heparin immobilized to a BIAcore sensor chip. Interaction of FGF2 with tyrosine-kinase receptors (FGFRs), heparan sulfate proteoglycans (HSPGs), and α
v
β
3
integrin is required for biological response in endothelial cells. Similar to LMWH, LMW-K5 derivatives abrogate the formation of HSPG/FGF2/FGFR ternary complexes by preventing FGF2-mediated attachment of FGFR1-overexpressing cells to HSPG-bearing cells and inhibit FGF2-mediated endothelial cell proliferation. However, LMW-K5 derivatives, but not LMWH, also inhibit FGF2/α
v
β
3
integrin interaction and consequent FGF2-mediated endothelial cell sprouting in vitro and angiogenesis in vivo in the chick embryo chorioallantoic membrane.

Conclusions—

LMW
N
,
O
-sulfated K5 derivatives affect both HSPG/FGF2/FGFR and FGF2/α
v
β
3
interactions and are endowed with FGF2 antagonist and antiangiogenic activity. These compounds may provide the basis for the design of novel LMW heparin-like angiostatic compounds.
Chemokines in the Pathogenesis of Vascular Disease
Authors: Charo Israel F. , Taubman Mark B.
Published: October 2004

Our increasing appreciation of the importance of inflammation in vascular disease has focused attention on the molecules that direct the migration of leukocytes from the blood stream to the vessel wall. In this review, we summarize roles of the chemokines, a family of small secreted proteins that selectively recruit monocytes, neutrophils, and lymphocytes to sites of vascular injury, inflammation, and developing atherosclerosis. Chemokines induce chemotaxis through the activation of G-protein-coupled receptors, and the receptors that a given leukocyte expresses determines the chemokines to which it will respond. Monocyte chemoattractant protein 1 (MCP-1), acting through its receptor CCR2, appears to play an early and important role in the recruitment of monocytes to atherosclerotic lesions and in the formation of intimal hyperplasia after arterial injury. Acute thrombosis is an often fatal complication of atherosclerotic plaque rupture, and recent evidence suggests that MCP-1 contributes to thrombin generation and thrombus formation by generating tissue factor. Because of their critical roles in monocyte recruitment in vascular and nonvascular diseases, MCP-1 and CCR2 have become important therapeutic targets, and efforts are underway to develop potent and specific antagonists of these and related chemokines.
Platelets Release CXCL4L1, a Nonallelic Variant of the Chemokine Platelet Factor-4/CXCL4 and Potent Inhibitor of Angiogenesis
Authors: Struyf Sofie , Burdick Marie D. , Proost Paul , Van Damme Jo , Strieter Robert M.
Published: October 2004

Platelet factor-4 (PF-4)/CXCL4 was the first chemokine described to inhibit neovascularization. Here, the product of the nonallelic variant gene of CXCL4, PF-4
var1
/PF-4
alt
, designated CXCL4L1, was isolated for the first time from thrombin-stimulated human platelets and purified to homogeneity. Although secreted CXCL4 and CXCL4L1 differ in only three amino acids, CXCL4L1 was more potent in inhibiting chemotaxis of human microvascular endothelial cells toward interleukin-8 (IL-8)/CXCL8 or basic fibroblast growth factor (bFGF). In vivo, CXCL4L1 was also more effective than CXCL4 in inhibiting bFGF-induced angiogenesis in rat corneas. Thus, activated platelets release CXCL4L1, a potent regulator of endothelial cell biology, which affects angiogenesis and vascular diseases.