bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of membrane‐bound serine proteinase matriptase as processing enzyme of insulin‐like growth factor binding protein‐related protein‐1 (IGFBP‐rP1/angiomodulin/mac25)
Authors: Ahmed Sanjida , Jin Xinlian , Yagi Motoki , Yasuda Chie , Sato Yuichiro , Higashi Shouichi , Lin Chen‐Yong , Dickson Robert B. , Miyazaki Kaoru
Published: January 2006

Insulin‐like growth factor (IGF) binding protein‐related protein‐1 (IGFBP‐rP1) modulates cellular adhesion and growth in an IGF/insulin‐dependent or independent manner. It also shows tumor‐suppressive activity in vivo. We recently found that a single‐chain IGFB‐rP1 is proteolytically cleaved to a two‐chain form by a trypsin‐like, endogenous serine proteinase, changing its biological activities. In this study, we attempted to identify the IGFBP‐rP1‐processing enzyme. Of nine human cell lines tested, seven cell lines secreted IGFBP‐rP1 at high levels, and two of them, ovarian clear cell adenocarcinoma (OVISE) and gastric carcinoma (MKN‐45), highly produced the cleaved IGFBP‐rP1. Serine proteinase inhibitors effectively blocked the IGFBP‐rP1 cleavage in the OVISE cell culture. The conditioned medium of OVISE cells did not cleave purified IGFBP‐rP1, but their membrane fraction had an IGFBP‐rP1‐cleaving activity. The membrane fraction contained an 80‐kDa gelatinolytic enzyme, which was identified as the membrane‐type serine proteinase matriptase (MT‐SP1) by immunoblotting. When the membrane fraction was separated by SDS/PAGE, the IGFBP‐rP1‐cleaving activity comigrated with matriptase. A soluble form of matriptase purified in an inhibitor‐free form efficiently cleaved IGFBP‐rP1 at the same site as that found in a naturally cleaved IGFBP‐rP1. Furthermore, small interfering RNAs for matriptase efficiently blocked both the matriptase expression and the cleavage of IGBP‐rP1 in OVISE cells. These results demonstrate that IGFBP‐rP1 is processed to the two‐chain form by matriptase on the cell surface.
Fatty acid synthesis
Authors: von Wettstein‐Knowles Penny , Olsen Johan G. , McGuire Kirsten A. , Henriksen Anette
Published: January 2006

β‐Ketoacyl‐acyl carrier protein (ACP) synthase enzymes join short carbon units to construct fatty acyl chains by a three‐step Claisen condensation reaction. The reaction starts with a trans thioesterification of the acyl primer substrate from ACP to the enzyme. Subsequently, the donor substrate malonyl‐ACP is decarboxylated to form a carbanion intermediate, which in the third step attacks C1 of the primer substrate giving rise to an elongated acyl chain. A subgroup of β‐ketoacyl‐ACP synthases, including mitochondrial β‐ketoacyl‐ACP synthase, bacterial plus plastid β‐ketoacyl‐ACP synthases I and II, and a domain of human fatty acid synthase, have a Cys‐His‐His triad and also a completely conserved Lys in the active site. To examine the role of these residues in catalysis, H298Q, H298E and six K328 mutants of Escherichia coliβ‐ketoacyl‐ACP synthase I were constructed and their ability to carry out the trans thioesterification, decarboxylation and/or condensation steps of the reaction was ascertained. The crystal structures of wild‐type and eight mutant enzymes with and/or without bound substrate were determined. The H298E enzyme shows residual decarboxylase activity in the pH range 6–8, whereas the H298Q enzyme appears to be completely decarboxylation deficient, showing that H298 serves as a catalytic base in the decarboxylation step. Lys328 has a dual role in catalysis: its charge influences acyl transfer to the active site Cys, and the steric restraint imposed on H333 is of critical importance for decarboxylation activity. This restraint makes H333 an obligate hydrogen bond donor at Nε, directed only towards the active site and malonyl‐ACP binding area in the fatty acid complex.
Recruitment of transcription complexes to the β‐globin locus control region and transcription of hypersensitive site 3 prior to erythroid differentiation of murine embryonic stem cells
Authors: Levings Padraic P. , Zhou Zhuo , Vieira Karen F. , Crusselle‐Davis Valerie J. , Bungert Jörg
Published: January 2006

Eukaryotic chromosomal DNA is densely packaged in the nucleus and organized into discrete domains of active and inactive chromatin. Gene loci that are activated during the process of cell differentiation undergo changes that result in modifications of specific histone tail residues and in loosening of chromatin structure. The β‐globin genes are expressed exclusively in erythroid cells. High‐level expression of these genes is mediated by a locus control region (LCR), a powerful DNA regulatory element composed of several DNase I hypersensitive (HS) sites and located far upstream of the β‐globin genes. Here we show that RNA polymerase II and specific histone modifications that mark transcriptionally active chromatin domains are associated with the LCR core elements HS2 and HS3 in murine embryonic stem cells prior to differentiation along the erythroid lineage. At this stage HS3 is abundantly transcribed. After in vitro differentiation, RNA Polymerase II can also be detected at the embryonic ε‐ and adult β‐globin genes. These results are consistent with the hypothesis that activation of the β‐globin gene locus is initiated by protein complexes recruited to the LCR.
Probing dark matter with X-ray binaries
Authors: Dehnen Walter , King Andrew
Published: January 2006

Low-mass X-ray binaries (LMXBs), which occur in old stellar populations, have velocities exceeding those of their parent distribution by at least 20 km s−1. This makes them ideal probes for dark matter, in particular in dwarf spheroidals (dSph), where the LMXBs should penetrate well outside the visible galaxy. We argue that the most likely explanation of the observation of LMXBs in the Sculptor dSph by Maccarone et al. is the presence of a dark matter halo of ≳109 M⊙, corresponding to a total-mass to light ratio of ≳600 (M/LV)⊙. In this case there should be an extended halo of LMXBs which may be observable.
A STUDY ON SUITABILITY OF FOUR ENRICHMENT BROTHS FOR PCR‐BASED DETECTION OF LISTERIA MONOCYTOGENES FROM RAW MEAT
Authors: BALAMURUGAN J. , BHILEGAONKAR K.N. , AGARWAL R.K.
Published: January 2006

Four enrichment broths were evaluated for their compatibility with the polymerase chain reaction (PCR) for detection of Listeria monocytogenes from raw meat after single‐step enrichment. Standardized PCR protocols for listeriolysin O (hlyA) gene were used for the species‐specific identification of L. monocytogenes. Four broths, namely, modified University of Vermont broth (MUVM), Listeria enrichment broth (LEB), Fraser broth (FB) and polymyxin, acriflavin, lithium chloride, ceftazidime, aesculin, mannitol, egg yolk broth (PALCAM) , were inoculated with L. monocytogenes. The enriched cultures were subjected for PCR. Similarly, meat samples were artificially spiked with various concentrations of L. monocytogenes, these spiked samples were enriched in the above‐mentioned four broths and subjected to PCR to determine the medium that was most compatible for PCR‐based detection of L. monocytogenes. The aliquots taken during different incubation periods were subjected to three different procedures for the concentration of the target organism for use in PCR. Results revealed that MUVM was better than other broths for the detection of L. monocytogenes by both PCR and cultural method; moreover, it was able to support the growth of as low as 10 cfu/g of meat. Concentration of the target organisms by centrifugation and washing with PCR buffer was the most suitable method for improving PCR performance for detection of L. monocytogenes. Goat (n = 67) and buffalo (n = 45) meat samples from local markets were also screened by both PCR and cultural method to validate the results obtained from the spiking studies. Both results were in agreement in spiking studies as well as screening of market meat samples.
FOOD‐HANDLING PRACTICES OF IRISH BEEF CONSUMERS
Authors: MAHON DENISE , COWAN CATHAL , HENCHION MAEVE , FANNING MARTIN
Published: January 2006

Illnesses from foodborne pathogens are one of the most widespread public health concerns worldwide. Because of the more frequent contamination of foods of animal origin with these pathogens, these foods have an inherent food safety risk and require caution when handling. Minced beef, with its large surface area and its moist and nutritive flesh, is particularly susceptible to contamination.

This study was designed to investigate consumer food‐handling practices in regard to minced beef. A sample of 485 minced beef consumers, who were also the main shoppers and food handlers in their homes, were interviewed. It was found out that many failed to store minced beef on the correct shelf of the fridge and to use the correct procedures for defrosting meat. These should be the focus of future food safety campaigns, especially targeting those with lower education levels and from lower socio‐economic groups.
EFFECTS OF CETYLPYRIDINIUM CHLORIDE, LACTIC ACID AND SODIUM BENZOATE ON POPULATIONS OF LISTERIA MONOCYTOGENES AND STAPHYLOCOCCUS AUREUS ON BEEF
Authors: ÖZDEMIR HAYDAR , GÜCÜKOĞLU ALI , PAMUK ŞEBNEM
Published: January 2006

The effects of cetylpyridinium chloride (CPC), lactic acid (LA) and sodium benzoate (SB) on the Listeria monocytogenes and Staphylococcus aureus populations on beef were evaluated. Samples of longissimus dorsi beef muscle inoculated with L. monocytogenes and S. aureus were dipped into 0.5, 2.0 and 0.3% of CPC, LA and SB, respectively, or an equal mix of any two solutions for 15 s at 35C ± 1. CPC demonstrated 1.93 and 2.15 log reductions of L. monocytogenes and S. aureus, respectively, on the fifth day of refrigerated storage, whereas LA reduced L. monocytogenes and S. aureus by 1.72 and 0.99 log, respectively.

Results indicated that the single intervention of CPC and LA solutions were more effective than mixed solutions of these decontaminants to reduce the pathogens of concern on beef.
A compact apparatus for muon lifetime measurement and time dilation demonstration in the undergraduate laboratory
Authors: Coan Thomas , Liu Tiankuan , Ye Jingbo
Published: January 2006

We describe a compact apparatus for measuring the charge-averaged lifetime of atmospheric muons in plastic scintillator using low-cost, low-power electronics. We present measurements of the stopping rate of atmospheric muons as a function of altitude to demonstrate relativistic time dilation. The apparatus is designed for the advanced undergraduate physics laboratory and is suitable for field measurements.
Helicity conservation under Reidemeister moves
Authors: Bouzarth Elizabeth L. , Pfister Hans
Published: January 2006

We discuss a connection between two fields that appear to have little in common: plasma physics and mathematical knot theory. Plasma physicists are interested in studying helicity conservation in magnetic flux ropes and knot theorists commonly consider “Reidemeister moves,” transformations that preserve a property called “knottedness.” To study the tangling, twisting, and untwisting of magnetic flux ropes, it is helpful to know which topological transformations conserve helicity. Although the second and third types of Reidemeister moves applied to a magnetic flux rope clearly conserve the helicity of the flux rope, the first type of Reidemeister move appears to be in conflict with helicity conservation. We show that all three Reidemeister moves conserve helicity in magnetic flux ropes.
The indirect measurement of biomechanical forces in the moving human body
Authors: Cluss Melanie , Laws Kenneth , Martin Natalie , Nowicki T. Scott , Mira Allan
Published: January 2006

Inexpensive experimental techniques now exist for indirectly measuring forces within the moving human body. These techniques involve nontrivial applications of basic physical principles, have practical uses, and are appropriate for undergraduate experimentation. A two-dimensional video motion analysis is used to find the accelerations of various parts of the body, and anatomical geometry is used to determine specific biomechanical forces and torques. The simple movement of a dancer landing from a vertical jump is analyzed through the use of a theoretical model of the leg to find the forces in the tendons attached to the knee. It is shown that these forces can be sufficiently large to lead to injury if jumps are performed repetitively.
The radiation of a uniformly accelerated charge is beyond the horizon: A simple derivation
Authors: de Almeida Camila , Saa Alberto
Published: January 2006

By exploring some elementary consequences of the covariance of Maxwell’s equations under general coordinate transformations, we show that even though inertial observers can detect electromagnetic radiation emitted from a uniformly accelerated charge, comoving observers will see only a static electric field. This analysis can add insight into one of the most celebrated paradoxes of the last century.
Drug Resistance in Leishmaniasis
Authors: Croft Simon L. , Sundar Shyam , Fairlamb Alan H.
Published: January 2006

Leishmaniasis is a complex disease, with visceral and cutaneous manifestations, and is caused by over 15 different species of the protozoan parasite genus Leishmania. There are significant differences in the sensitivity of these species both to the standard drugs, for example, pentavalent antimonials and miltefosine, and those on clinical trial, for example, paromomycin. Over 60% of patients with visceral leishmaniasis in Bihar State, India, do not respond to treatment with pentavalent antimonials. This is now considered to be due to acquired resistance. Although this class of drugs has been used for over 60 years for leishmaniasis treatment, it is only in the past 2 years that the mechanisms of action and resistance have been identified, related to drug metabolism, thiol metabolism, and drug efflux. With the introduction of new therapies, including miltefosine in 2002 and paromomycin in 2005-2006, it is essential that there be a strategy to prevent the emergence of resistance to new drugs; combination therapy, monitoring of therapy, and improved diagnostics could play an essential role in this strategy.
Prospects for Vaccine Prevention of Meningococcal Infection
Authors: Harrison Lee H.
Published: January 2006

Neisseria meningitidisis the leading cause of bacterial meningitis in the United States and worldwide. A serogroup A/C/W-135/Y polysaccharide meningococcal vaccine has been licensed in the United States since 1981 but has not been used universally outside of the military. On 14 January 2005, a polysaccharide conjugate vaccine that covers meningococcal serogroups A, C, W-135, and Y was licensed in the United States for 11- to 55-year-olds and is now recommended for the routine immunization of adolescents and other high-risk groups. This review covers the changing epidemiology of meningococcal disease in the United States, issues related to vaccine prevention, and recommendations on the use of the new vaccine.
Real-Time PCR in Clinical Microbiology: Applications for Routine Laboratory Testing
Authors: Espy M. J. , Uhl J. R. , Sloan L. M. , Buckwalter S. P. , Jones M. F. , Vetter E. A. , Yao J. D. C. , Wengenack N. L. , Rosenblatt J. E. , Cockerill F. R. , Smith T. F.
Published: January 2006

Real-time PCR has revolutionized the way clinical microbiology laboratories diagnose many human microbial infections. This testing method combines PCR chemistry with fluorescent probe detection of amplified product in the same reaction vessel. In general, both PCR and amplified product detection are completed in an hour or less, which is considerably faster than conventional PCR detection methods. Real-time PCR assays provide sensitivity and specificity equivalent to that of conventional PCR combined with Southern blot analysis, and since amplification and detection steps are performed in the same closed vessel, the risk of releasing amplified nucleic acids into the environment is negligible. The combination of excellent sensitivity and specificity, low contamination risk, and speed has made real-time PCR technology an appealing alternative to culture- or immunoassay-based testing methods for diagnosing many infectious diseases. This review focuses on the application of real-time PCR in the clinical microbiology laboratory.
THE ANGULAR MOMENTUM DEPENDENT CALCULATION OF THE GROUND STATE ENERGY OF LIQUID 3He
Authors: MODARRES M.
Published: January 2006

We investigate the possible angular momentum, l, dependence of the ground state energy of normal liquid 3 He . The method of lowest order constrained variational (LOCV) which includes the three-body cluster energy and normalization constraint (LOCVE) is used with angular momentum dependent two-body correlation functions. A functional minimization is performed with respect to each l-channel correlation function. It is shown that this dependence increases the binding energy of liquid 3 He by 8% with respect to calculations without angular momentum dependent correlation functions. The l=0 state has completely different behavior with respect to other l-channels. It is also found that the main contribution from potential energy comes from the l=1 state (p-waves) and the effect of l≥11 is less than about 0.1%. The effective interactions and two-body correlations in different channels are being discussed. Finally we conclude that this l-dependence can be verified experimentally by looking into the magnetization properties of liquid helium 3 and interatomic potentials.
DIRECT NUMERICAL SIMULATION OF TURBULENT FLOWS IN A VERTICAL ROTATING OPEN-CHANNEL
Authors: LI BU-YANG , LIU NAN-SHENG , LU XI-YUN
Published: January 2006

Direct numerical simulation (DNS) is carried out to study turbulence characteristics in a vertical rotating open-channel with the rotation number N τ = 0-0.12 and the Reynolds number Re τ = 180 based on the wall friction velocity of non-rotating case and the channel depth. Here, two typical rotation regimes are identified. As 0 < N τ < 0.06, the turbulence statistics correlated with the spanwise velocity fluctuation are enhanced since the shear rate of spanwise mean flow induced by Coriolis force increases; however, the other statistics are suppressed. As N τ > 0.06, the turbulence statistics are suppressed significantly because the effect of Coriolis force plays as a dominant role.
NUMERICAL SIMULATION OF 3D FLUID-STRUCTURE INTERACTION USING AN IMMERSED MEMBRANE METHOD
Authors: XIA G. H. , ZHAO Y. , YEO J. H.
Published: January 2006

In this paper, an immersed membrane method (IMM) is proposed for the simulation of three-dimensional (3D) fluid-structure interaction phenomena in a mechanical heart valve (MHV).
NUMERICAL STUDIES OF ASYMMETRIC VORTEX FLOWS AROUND A SLENDER BODY AT HIGH ANGLE OF ATTACK
Authors: GUO TONGQING , LU ZHILIANG
Published: January 2006

The asymmetric vortex flows about slender bodies at high angle of attack are investigated numerically. 3D O-O type multi-block structured grids are adopted for the computation, and a series of small spatial disturbances are imposed on the leeward body surface near the tip to trigger the asymmetry. The unsteady Navier-Stokes equations are solved using a dual-time method based on the cell-centered finite-volume scheme. Comparisons between numerical results and experimental data demonstrate that the asymmetric vortex pattern observed in the experiment is successfully simulated. In a certain small perturbation level, the magnitude of the side-force is independent of the size of the spatial perturbation, but its direction is dependent on the direction of the spatial perturbation, i.e. a counterclockwise or clockwise circumferential angle from the leeward meridian. When perturbation is removed, the flow field returns to its original asymmetric shape after a period of oscillation.
A FULLY IMPLICIT SOLVER OF 3-D EULER EQUATIONS ON MULTIBLOCK CURVILINEAR GRIDS
Authors: SI HAI-QING , WANG TONG-GUANG , LUO XIAO-YUN
Published: January 2006

A fully implicit unfactored algorithm for three-dimensional Euler equations is developed and tested on multi-block curvilinear meshes. The convective terms are discretized using an upwind TVD scheme. The large sparse linear system generated at each implicit time step is solved by GMRES* method combined with the block incomplete lower-upper preconditioner. In order to reduce the memory requirements and the matrix-vector operation counts, an approximate method is used to derive the Jacobian matrix, which only costs half of the computational efforts of the exact Jacobian calculation. The comparison between the numerical results and the experimental data shows good agreement, which demonstrates that the implicit algorithm presented is effective and efficient.
ON THE CHARACTERISTICS OF THE MACH STEM
Authors: REN YU-XIN , TAN LIAN-HUA , GAO BO , WU ZI-NIU
Published: January 2006

The characteristics of Mach stem in steady and unsteady Mach reflections are important in supersonic vehicle design. In this paper we give an overview of the current status of the study on the height and shape characteristics of Mach stem. Notably, we will show that in many cases the shape of the Mach stem seems to be well approximated by a circular arc.
EFFECT OF VORTEX BREAKDOWN ON MASS TRANSFER IN A CELL CULTURE BIOREACTOR
Authors: YU PENG , LEE T. S. , ZENG Y. , LOW H. T.
Published: January 2006

The present work shows that vortex breakdown may also occur in a bioreactor for animal cell or tissue culture. The aim is to study the effect of vortex breakdown on the fluid environment for cell growth, particularly hydrodynamic stress and mass transfer. A numerical simulation of the fluid flow and oxygen transfer in a cylindrical bioreactor is presented, in which a rotating base wall is used to generate the medium flow and mixing. The steady and laminar, axisymmetric Navier-Stokes and species equations are solved by the numerical model based on finite volume method. The hydrodynamic stress and oxygen transfer conditions are systematically studied by varying the two key parameters which determine the flow behavior: bioreactor aspect ratio H/R and a rotation Reynolds number Re=ΩR2/ν. It is found that the oxygen concentration at the attached breakdown vortex center is significantly higher than that at the main recirculation center but the hydrodynamic stress level is almost similar in the two regions. The results would provide guidance on choosing the proper operating parameters for cell or tissue culture.
THE STABILITY ANALYSIS OF HEAT TRANSFER IN SATURATED LIQUID FILM OF THE SPECIAL MATERIALS
Authors: CHENG YOULIANG , LI XIN , FAN ZHONGYAO , YING BOFEN
Published: January 2006

Representing surface tension by nonlinear relationship on temperature, the boundary value problem of linear stability differential equation on small perturbation is derived. Under the condition of the isothermal wall the effects of nonlinear surface tension on stability of heat transfer in saturated liquid film of different liquid low boiling point gases are investigated as wall temperature is varied.
NUMERICAL SIMULATION OF THE FLOWS OVER TWO TANDEM CYLINDERS BY LATTICE BOLTZMANN METHOD
Authors: KU XIAOKE , LIN JIANZHONG
Published: January 2006

Flows over two tandem cylinders are simulated numerically based on the lattice Boltzmann method. The pressure distribution on the cylinders for varying distance between the two cylinders at different Reynolds numbers is depicted. The results show that the minimum pressure on the front cylinder does not occur at the stagnation point because of the existence of the back cylinder. The distance between the point with minimum pressure and the stagnation point becomes large with increasing Re number. The minimum pressure on the back cylinder varies with the distance between the two cylinders. The effective distance of interaction between two cylinders is less than 4d with d being the diameter of the cylinder.
TECHNIQUES TO ENHANCE FLUID MICRO-MIXING AND CHAOTIC MICROMIXERS
Authors: CHEW Y. T. , XIA H. M. , SHU C. , WAN S. Y. M.
Published: January 2006

With fast development of microfluidic systems, fluid micro-mixing becomes a very important issue. In this paper, recent developments on various micromixers and their working mechanisms are reviewed, including the external agitation methods applied in active mixing and the channel geometries adopted in passive mixer design. The chaotic mixing and the influences of Re would be mainly discussed. At moderate and high Re , the fluid inertial effects usually facilitate the chaotic mixing. At low Re , generation of chaotic advection becomes more difficult but can still be achieved through fluid manipulations such as stretching and folding. Chaotic mixers can be characterized using dynamical system techniques, such as Poincaré plot, and Lyapunov exponent.
LINKAGE BETWEEN CHAOS DYNAMICS AND THE ONSET OF TURBULENCE IN A FLAT PLATE TRANSITIONAL BOUNDARY LAYER
Authors: LI R. Q.
Published: January 2006

An experiment was performed to investigate the onset of turbulence in a flat plate boundary layer. The correlation dimension was calculated from the experimental data by means of chaos dynamics and the existence of the strange attractor was shown in the transitional processes. Therefore, the transitional processes to turbulence have been classified by not only the instability theory but also the nonlinear chaotic analysis. The relationship between the correlation dimension and the streamwise positions implies a natural connection between chaos dynamics and the onset of turbulence in a plate boundary layer, so transition is linked to the chaotic motion.
A STUDY ON FLOW REGIME NEAR CRITICAL RAYLEIGH NUMBER FOR BUOYANCY-DRIVEN CAVITY FLOW
Authors: CHANG KEH-CHIN , WU WEN-CHUNG
Published: January 2006

A benchmark problem with air medium in a square cavity heated by a vertical side is studied in a Ra range near its critical value without using the usual model approximations, such as Boussinesq or low-Mach-number approximation. Two analysis methods of power spectrum and phase trajectory are adopted to distinguish the flow pattern in the cavity. It demonstrates how the flow evolves from transition to turbulent regimes with increasing Ra values.
THE EFFECT OF TEMPERATURE ON FRICTION CHARACTERISTICS OF INCOMPRESSIBLE FLOW IN LONG RECTANGULAR MICROCHANNELS
Authors: CHEN C. S. , LIN M. H.
Published: January 2006

This paper develops an efficient three-dimensional numerical procedure to predict incompressible flow in long microchannels. The major advantage of the present numerical procedure is its fast speed due to the parabolic character of the governing equations.
LIQUID-DIAPHRAGM INTERACTION OF MICROPUMP
Authors: WU JIANKANG , LU LIJUN
Published: January 2006

This paper employs a thickness-averaged shallow water model to approximate periodical flows in a piezoelectric micropump. The fluid pressure equation is combined with the vibration equation of silicon diaphragm to construct a liquid-solid coupled equation. Numerical results of mode analysis of the coupled system indicate that the natural frequencies of coupled system are much lower than those of the non-coupled system. The relationships of the first order amplitude-frequency of the silicon diaphragm, and the flow rate-frequency of micropump are also given in this paper.
ONE-STAGE IDENTIFICATION OF CONTINUOUS TIME DELAY SYSTEMS WITH UNKNOWN INITIAL CONDITIONS AND DISTURBANCE FROM PULSE TESTS
Authors: WANG QING-GUO , LIU MIN , HANG CHANG CHIEH
Published: January 2006

In this paper, an identification method is proposed for linear continuous time delay processes with unknown non-zero initial condition and disturbance from pulse tests. Multiple integral is used and integral intervals are specifically chosen to enable easy identification of the system parameters in one step. The effectiveness of the identification method is demonstrated through simulations.
NUMERICAL RESEARCH ON A SPECIAL FLUID PHENOMENON: RANQUE-HILSCH EFFECT
Authors: LIU J. Y. , GONG M. Q. , ZHANG Y. , HONG H. , WU J. F.
Published: January 2006

An application of CFD model for the simulation of a strongly swirling and high speed flow in the vortex tube is presented in this paper. A partly modified standard K-ε turbulent model has been used to investigate the flow characteristics and energy separation effect in the vortex tube. It is found that there is an obvious energy separation effect in the vortex tube and the numerical solutions of the flow and temperature fields agree well with the experiments. More detailed flow features are obtained by the CFD calculation. Based on the validated numerical model, the influence of the cold flow fraction on the energy separation effect is also investigated and compared with experimental results.
PARAMETER IDENTIFICATION APPROACHES TO FRACTAL MODEL OF MASS TRANSPORT FOR UNSATURATED SOILS
Authors: LI SHOUJU , LIU YINGXI
Published: January 2006

Modeling flow and solute transport in the unsaturated zone requires specifying values for soil hydraulic conductivity. Fractal models describe hierarchical systems and are suitable to model soil structure and soil hydraulic properties. The objectives of the paper are to propose a parameter identification approach and to determine hydraulic parameters using inverse modeling. The inverse problem of parameter identification is formulated as an optimization problem. In order to identify hydraulic parameters of soils efficiently and in a robust manner, the genetic algorithm is presented for the parameter identification of the fractal models. The investigation shows that the proposed inversion procedure is more superior for applying to parameter identification of fractal model of mass transport for unsaturated soils.
RESEARCH ON THE WAVE-INDUCED SHIP MOTIONS IN FRONT OF DIFFERENT TYPES OF WHARF
Authors: LI YAN BAO , JIANG XUE LIAN
Published: January 2006

One important function of the port is to protect ship or some other facilities from wave attack so as to stably handle cargoes. In current design codes, there are mainly two expressions of the tranquility standard of harbor basin: one is the acceptable wave height in front of wharf; the other is the tolerable amplitude of ship motion. However, ship motions are affected by some more factors simultaneously, such as wave frequency, wave height, incident wave direction, ship properties and wharf type. This paper presents some computed results of the wave-induced ship motions on the basis of a port case in China. First, the Simple Green Function method is employed to solve and compare the 2-dimension hydrodynamic coefficients in front of open or bulkhead wharf. The results show a great difference between them. Then, this paper computes and discusses the ship motions in front of open wharf at different wave frequencies and incident wave directions.
WAVE PROPAGATION ANALYSIS IN A PRESSURE-WAVE-REFRIGERATOR
Authors: ZHAO W. , JIANG Z. L. , YU H. R. , SAITO T. , TAKAYAMA K.
Published: January 2006

Pressure wave refrigerators (PWR) refrigerate the gas through periodical expansion waves. Due to its simple structure and robustness, PWR may have many potential applications if the efficiency becomes competitive with existing alternative devices. In order to improve the efficiency, the characteristics of wave propagation in a PWR are studied by experiment, numerical simulation and theoretical analysis. Based on the experimental results and numerical simulation, a simplified model is suggested, which includes the assumptions of flux-equilibrium and conservation of the free energy. This allows the independent analysis of the operation parameters and design specifics. Furthermore, the optimum operation condition can be deduced. Some considerations to improve the PWR efficiency are also given.
TEMPERATURE EFFECT ON THERMOMECHANICAL PROPERTIES OF BERYLLIUM CHALCOGENIDES BeS, BeSe AND BeTe
Authors: BENKABOU F.
Published: January 2006

We have used the molecular-dynamic method for the calculation of the structural, dynamic and elastic properties of group BeS , BeSe and BeTe compounds for temperature ranging from 300 to 1200 K. Tersoff potential has been used to model the interaction between the groups II–VI compound atoms. The structural properties of cubic BeS , BeSe and BeTe have been calculated, and good agreement between the calculated and experimental values have been found. We have also predicted the elastic constants and diffusion coefficients of BeS , BeSe and BeTe . The values found compare very well with the theoretical results. For the temperature range under study, all elastic constants and dynamic properties show a softening with increasing temperature very similar to the theoretical calculations.
MULTIPLE SOLUTIONS FOR NONLINEAR ELLIPTIC PROBLEMS WITH A DISCONTINUOUS NONLINEARITY
Authors: FILIPPAKIS MICHAEL E. , PAPAGEORGIOU NIKOLAOS S.
Published: January 2006

We consider a nonlinear elliptic equation driven by the p-Laplacian with a discontinuous nonlinearity. Such problems have a "multivalued" and a "single-valued" interpretation. We are interested in the latter and we prove the existence of at least two distinct solutions, both smooth and one strictly positive. Our approach is variational based on the nonsmooth critical point theory for locally Lipschitz functions, coupled with penalization and truncation techniques.
INTERIOR ERROR ESTIMATE FOR PERIODIC HOMOGENIZATION
Authors: GRISO GEORGES
Published: January 2006

In a previous paper about homogenization of the classical problem of diffusion in a bounded domain with sufficiently smooth boundary, we proved that the global error is of order ε1/2. Now, for an open set Ω with sufficiently smooth boundary [Formula: see text] and homogeneous Dirichlet or Neumann limit conditions, we show that in any open set strongly included in Ω the error is of order ε. If the open set Ω ⊂ ℝnis of polygonal (n = 2) or polyhedral (n = 3) boundary, we also give the global and interior error estimates.
Impact of Prosthesis-Patient Mismatch on Long-Term Survival in Patients With Small St Jude Medical Mechanical Prostheses in the Aortic Position
Authors: Mohty-Echahidi Dania , Malouf Joseph F. , Girard Steve E. , Schaff Hartzell V. , Grill Diane E. , Enriquez-Sarano Maurice E. , Miller Fletcher A.
Published: January 2006

Background—

The impact of aortic prosthesis-patient mismatch (P-PtM) on long-term survival is unclear.

Methods and Results—

Between 1985 and 2000, 388 patients at Mayo Clinic in Rochester, Minn, underwent aortic valve replacement (AVR) with 19- or 21-mm St Jude Medical prostheses and had transthoracic echocardiography within 1 year after AVR. Mean age of patients was 62±13 years; 69% were female. Prosthesis effective orifice area (EOA) was derived from the continuity equation. P-PtM was classified as severe (indexed EOA ≤0.60 cm
2
/m
2
), moderate (0.60 cm
2
/m
2
<indexed EOA≤0.85 cm
2
/m
2
), or not hemodynamically significant (indexed EOA >0.85 cm
2
/m
2
). P-PtM was severe in 66 patients (17%), moderate in 168 (43%), and not hemodynamically significant in 154 (40%). Patients with severe P-PtM had a significantly larger body surface area (
P
<0.0001), higher mean gradient (
P
<0.0001), lower preoperative (
P
<0.0001) and postoperative (
P
<0.0001) ejection fractions, and lower stroke volume (
P
<0.0001) and more often received a 19-mm prosthesis (
P
=0.0008) than patients with moderate or no hemodynamically significant mismatch. For patients with severe mismatch, 5-year survival rates (72±6%) and 8-year survival rates (41±8%) were significantly less than for patients with moderate mismatch (80±3% and 65±5%;
P
=0.026) or no hemodynamically significant mismatch (85±3% and 74±5%;
P
=0.002). On multivariate analysis after adjustment for other predictors of outcome, severe mismatch was associated with higher mortality (hazard ratio 2.18; 95% confidence interval 1.24 to 3.85;
P
=0.007) and higher incidence of congestive heart failure (hazard ratio 3.1; 95% confidence interval 1.3 to 7.4;
P
=0.009) than no hemodynamically significant mismatch.

Conclusions—

Severe P-PtM is an independent predictor of higher long-term mortality and congestive heart failure in patients with small St Jude Medical aortic valve prostheses. For patients undergoing AVR who are at risk of severe mismatch, every effort should be made to use a larger prosthesis or to consider a prosthesis with a larger EOA.
Community Lay Rescuer Automated External Defibrillation Programs
Authors: Aufderheide Tom , Hazinski Mary Fran , Nichol Graham , Steffens Suzanne Smith , Buroker Andrew , McCune Robin , Stapleton Edward , Nadkarni Vinay , Potts Jerry , Ramirez Raymond R. , Eigel Brian , Epstein Andrew , Sayre Michael , Halperin Henry , Cummins Richard O.
Published: January 2006

Cardiovascular disease is a leading cause of death for adults ≥40 years of age. The American Heart Association (AHA) estimates that sudden cardiac arrest is responsible for about 250 000 out-of-hospital deaths annually in the United States. Since the early 1990s, the AHA has called for innovative approaches to reduce time to cardiopulmonary resuscitation (CPR) and defibrillation and improve survival from sudden cardiac arrest. In the mid-1990s, the AHA launched a public health initiative to promote early CPR and early use of automated external defibrillators (AEDs) by trained lay responders in community (lay rescuer) AED programs. Between 1995 and 2000, all 50 states passed laws and regulations concerning lay rescuer AED programs. In addition, the Cardiac Arrest Survival Act (CASA, Public Law 106-505) was passed and signed into federal law in 2000. The variations in state and federal legislation and regulations have complicated efforts to promote lay rescuer AED programs and in some cases have created impediments to such programs. Since 2000, most states have reexamined lay rescuer AED statutes, and many have passed legislation to remove impediments and encourage the development of lay rescuer AED programs. The purpose of this statement is to help policymakers develop new legislation or revise existing legislation to remove barriers to effective community lay rescuer AED programs. Important areas that should be considered in state legislation and regulations are highlighted, and sample legislation sections are included. Potential sources of controversy and the rationale for proposed legislative components are noted. This statement will not address legislation to support home AED programs. Such recommendations may be made after the conclusion of a large study of home AED use.
Hyperlinked Dutch-Iranian Cyberspace
Authors: van den Bos Matthijs
Published: January 2006

Studies of the Dutch-Iranian diaspora are rare, but all indicate features that set it apart from other migrant communities in the Netherlands. It appears from these surveys that Dutch-Iranians have low levels of communal organization and sparsely knit networks. This article maintains that the pattern also holds for online Dutch-Iranian community structures, and builds its case on an examination of hyperlinks between websites of Iranians in the Netherlands. Second, the article examines sectors and their mutual relations in online Dutch-Iranian networks. It is argued, against what may be deduced from established theory and observations of Iranian diasporas, that networks organized around cultural content are the most inclusive and central and those which centre upon politics, the most exclusive and isolated. Linking patterns as well as website content serve to lay bare this structure of hyperlinked Dutch-Iranian cyberspace.
The Effects of Full-Time Domestic Workers on Married Women's Economic Activity Status in Hong Kong, 1981–2001
Authors: Chan Annie Hau-nung
Published: January 2006

In this article, logistic regression models were used to assess the effects of live-in domestic workers on married women's economic activity status. One percent random samples of the Hong Kong census and by-census data from the period 1981–2001 were used, and domestic workers are conceptualized as substitutes for wives’ domestic labour. Hypotheses are tested, which alternatively conceptualize domestic workers as substitutions for wives’ domestic labour, and as having symbolic functions for the family household and for the wives’ gender role. The presence of live-in domestic workers significantly increases the odds of mothers (but not non-mothers) being economically active. The effects of domestic workers on the odds of whether married women work vary over time and differ according to household income and wives’ educational attainment. Findings lend support to the symbolic functions of domestic workers and to the role of lifestyle preferences in women's employment. Further research using time budget, qualitative and attitudinal data are required in order to further understand the functions of domestic workers in the social reproduction of family and gender roles.
Assessing Progress in the Third Quest of the Historical Jesus
Authors: Evans Craig
Published: January 2006

Although historical-Jesus research in the last three decades has produced a great deal of divergent results, one is able to discern several important areas of progress. Perhaps the most important gain is in a renewed appreciation of the Judaic character of Jesus, his mission, and his world. New source material and more nuanced, contextual methodology have sharpened Jesus' profile as a Galilean Jew, standing in the tradition of Israel's redemption and restoration.
American Cultural Primacy in a New Media Order
Authors: Chalaby Jean K.
Published: January 2006

The paradigmatic shift from cultural imperialism to globalization in international communication has transformed the research agenda of the discipline. While new issues have come to the fore, others, such as the American pre-eminence in the world media market, tend to be ignored. This article revisits the old question of American dominance from the perspective of the new paradigm and suggests replacing the concept of cultural imperialism with that of cultural primacy. This shift allows us to analyse a salient fact of contemporary international communication without taking on board the assumptions and ideological biases of the cultural imperialism thesis. The article contrasts the limited reach of European media players with the global scope of US conglomerates and shows the extent of American dominance of the European audiovisual market. It argues that US-based media groups are set to become yet more prominent in the era of multichannel television because they have successfully adopted localization of content as an international strategy. The article concludes that to preserve consumer choice and programming diversity, European public broadcasters should forsake their nation-centric perspective, adapt their organizational structures to the international nature of the multichannel universe, and renew their combined efforts to launch thematic channels in genres in which they could make a significant contribution.
Rheology of latex films bonded to wood: influence of cross-linking
Authors: López-Suevos Francisco , E. Frazier Charles
Published: January 2006

Parallel-plate rheological analysis was conducted on two types of cross-linking poly(vinyl acetate) latex films: dry freestanding films, and dry films bonded directly to wood (composites). For each sample type, three levels of cross-linking were used: (1) little or no cross-linking of unaltered latex; (2) substantial cross-linking through AlCl3 catalysis of N-methylolacrylamide co-monomer; and (3) greater cross-linking from a phenol-formaldehyde resol additive, in addition to AlCl3 catalysis. Simple thermal scans revealed a strong wood/adhesive interaction; wood increased the base polymer T
g by ∼5°C in all adhesives. Relative to the simple thermal scans, time-temperature master curves provided more insight and information about the wood/adhesive interaction. Storage modulus and tan δ master curves both indicated that wood retarded adhesive cross-linking. Using time-temperature superposition, a segmental coupling analysis demonstrated that wood actually narrowed the breadth of the glass transition, or reduced segmental coupling. Cross-linking influenced segmental coupling, but in a fashion that was dependent on the presence or absence of wood. Wood-induced reductions in cross-linking and in segmental coupling were attributed to the diffusion of water-soluble reactive compounds away from the adhesive layer and into the bulk wood. Time/temperature equivalence provides a sensitive means to detect interactions between wood and viscoelastic adhesives.
Retrospective Measurement of Neutron Activation within the Pressure Circuit Steelwork of a Magnox Reactor and Comparison with Prediction
Authors: Thornton DA , Thiruarooran C , Allen DA , Harris AM , Holmes CG , Harvey CR
Published: January 2006

This paper describes a retrospective measurement of neutron activation rates within steel standpipe penetrations of the pressure circuit of the Wylfa nuclear power plant. This was carried out in support of neutron dose calculations. Samples were taken from a length of irradiated thermocouple cable and counted for the fast neutron reactions 54Fe(n,p) 54Mn, and 58Ni(n,p) 58Co, and the thermal neutron reactions 59Co(n,γ) 60Co, 58Fe(n,γ) 59Fe, and 50Cr(n,γ) 50Cr. By isolating clean sheath material and performing elemental analysis, it was possible to obtain absolute neutron flux data from the measurements over a broad range of locations. The measured data were compared with results obtained from a Monte Carlo calculation performed with the code mcbend. Structure observed within the measured and calculated thermal neutron flux distributions was used to confirm the position of the thermocouple samples relative to the reactor geometry. The measurements show that the calculations consistently over-predict fast and thermal neutron reactions. It is concluded that the model predicts spectra without significant bias, and consequently, that the standpipe dose recommendations are similarly over-predicted.
Performance Evaluation of “Duplex Hardened” Bearings for Advanced Turbine Engine Applications
Authors: Streit E , Brock J , Poulin P
Published: January 2006

Reliability is one of the most important competitive factors in aeroengines. Engine manufacturers have to provide guarantees for maintenance cost and dispatch reliability. Failures of mainshaft and gearbox bearings can represent a major debit to overall engine reliability. Duplex hardening (conventional hardening followed by special nitriding) has the potential to provide the bearing performance improvements necessary to yield increased engine reliability and reduced cost of ownership. The bearing rig tests performed demonstrate superior performance of duplex hardened M50 and M50NiL bearings over conventional M50 and M50NiL bearings under various operating conditions. Rig tests evaluating a wide range of operating conditions, such as high load, low or boundary lubrication, heavily contaminated lubrication, and oil off were performed. Additional tests were completed to evaluate the spall propagation behavior of duplex hardened bearings in comparison to conventional steel bearings. The results showed that the main benefits of using duplex hardened bearings arise in low or boundary lubrication conditions and contaminated lubrication conditions. The spall propagation tests showed that spall propagation rates are slower for duplex hardened M50 and M50NiL bearing components, hence allowing more time until catastrophic bearing failure in an aeroengine and other applications.