bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and mapping of EST-derived simple sequence repeat markers for hexaploid wheat
Authors: Yu Ju-Kyung , Dake Trevor M , Singh Sukhwinder , Benscher David , Li Wanlong , Gill Bikram , Sorrells Mark E
Published: October 2004

Expressed sequence tags (ESTs) are a valuable source of molecular markers. To enhance the resolution of an existing linkage map and to identify putative functional polymorphic gene loci in hexaploid wheat (Triticum aestivum L.), over 260 000 ESTs from 5 different grass species were analyzed and 5418 SSR-containing sequences were identified. Using sequence similarity analysis, 156 cross-species superclusters and 138 singletons were used to develop primer pairs, which were then tested on the genomic DNA of barley (Hordeum vulgare), maize (Zea mays), rice (Oryza sativa), and wheat. Three-hundred sixty-eight primer pairs produced PCR amplicons from at least one species and 227 primer pairs amplified DNA from two or more species. EST-SSR sequences containing dinucleotide motifs were significantly more polymorphic (74%) than those containing trinucleotides (56%), and polymorphism was similar for markers in both coding and 5' untranslated (UTR) regions. Out of 112 EST-SSR markers, 90 identified 149 loci that were integrated into a reference wheat genetic map. These loci were distributed on 19 of the 21 wheat chromosomes and were clustered in the distal chromosomal regions. Multiple-loci were detected by 39% of the primer pairs. Of the 90 mapped ESTs, putative functions for 22 were identified using BLASTX queries. In addition, 80 EST-SSR markers (104 loci) were located to chromosomes using nullisomic-tetrasomic lines. The enhanced map from this study provides a basis for comparative mapping using orthologous and PCR-based markers and for identification of expressed genes possibly affecting important traits in wheat.Key words: wheat, EST, SSR mapping.
Ability of scalloped deletion constructs to rescuesdmutant wing phenotypes inDrosophila melanogaster
Authors: Chow Leola , Berube Joel , Fromont Alice , Bell John B
Published: October 2004

Scalloped (SD) and Vestigial (VG) proteins physically interact to form a selector complex that activates genes involved in wing development in Drosophila melanogaster. SD belongs to a conserved family of transcription factors containing the TEA/ATTS DNA-binding motif. VG is also a nuclear protein providing the activator function for the SD VG complex. The TEA DNA-binding domain and the VG interacting domain (VID) of SD have been previously identified and described. However, they, and possibly other functional domains of SD, have not been thoroughly characterized in vivo. Herein, transgenic constructs encoding various truncations of SD were used to assess their respective ability to rescue the mutant wing phenotype of two viable sd recessive mutations (sdETX4and sd58d). The transgenic strains produced were also tested for the ability to induce further sd expression, an ability possessed by full length SD. The functional dissection of SD confirms that specific regions are necessary for wing development and provides further information as to how the SD VG complex functions to promote wing fate. Previous experiments have shown that expression of full length SD can cause a dominant negative wing phenotype. We show that expression of constructs that delete the SD DNA-binding domain can also cause a dominant negative phenotype in a background with either of the two tester sd strains. In contrast, SD constructs that delete the VID have no effect on the wing phenotype in either tester background. Finally, a significant portion of SD at the N-terminal end appears to be dispensable with respect to normal wing development, as this construct behaves the same as full length SD in our assays.Key words: Drosophila melanogaster, wing, scalloped, vestigial, nuclear protein.
Pendulum impacts into concrete bridge barriers reinforced with glass fibre reinforced polymer composite bars
Authors: El-Salakawy Ehab , Masmoudi Radhouane , Benmokrane Brahim , Brière Frédéric , Desgagné Gérard
Published: October 2004

This paper presents the results of a pendulum impact test that was carried out on full-scale types PL-2 and PL-3 concrete bridge barriers reinforced with glass fibre reinforced polymer (GFRP) bars. A new corrosion-free connection between the barrier wall and the slab using GFRP bent bars was investigated. For comparison purposes, the impact test was also performed on identical concrete barriers reinforced with conventional steel. A total of eight full-scale 10-m-long barrier prototypes were constructed and tested. The tests included four PL-2 and four PL-3 prototypes. For each type of barrier, two prototypes were reinforced with GFRP sand-coated bars and the other two were reinforced with steel bars. Pendulum crash tests using a 3.0-t pear-shaped iron ball were performed under the same conditions for each type of barrier. The behaviour of the barriers was evaluated in terms of cracking pattern, crack width, and strains in reinforcing bars. The results of this investigation led to the conclusion that the behaviour of PL-2 and PL-3 concrete bridge barriers reinforced with GFRP bars is very similar to that of their counterparts reinforced with conventional steel in terms of cracking, energy absorption, and strength.Key words: concrete bridges, bridge barriers, glass FRP bars, impact, pendulum crash test.
Structural controls on floc strength and transport
Authors: Droppo Ian G
Published: October 2004

An examination of how floc structure (internal and external) influences floc strength and transport is described. Samples were collected from both a natural river and a combined sewer outfall to provide significantly different structures for comparison. Regardless of floc type, the internal matrix was observed to be mediated by a dynamic microbial community. Microbial secretions of fibrilar extracellular polymeric substances (EPS) were found to be interwoven within the floc forming a framework and providing structural stability. This continually changing framework (due to floc physical, chemical, and biological activity) is shown to have extending influence over floc transport by modifying floc size, stability, density, porosity, and biochemical processes. This paper uses correlative microscopy to assess floc structure and behaviour in terms of the transport of sediments and associated contaminants. A conceptual model is provided which links floc strength to sediment transport (deposition and erosion) in the water column and at the sediment water interface.Key words: flocculation, bacteria, extracellular polymeric substances, stability, transport, structure.
Performance assessment of FC girder bridges in Alberta
Authors: Khattak Nadeem , Cheng J.J Roger
Published: October 2004

A large number of precast prestressed concrete multi-girder bridges were constructed in Alberta in the early 1960s. Major benefits of this type of construction included the elimination of the cast in place concrete bridge deck and the accelerated pace of construction in erecting the bridge. However, after providing 10 to 20 years of service, some of these bridges started to form longitudinal cracks in the deck directly over the girder joining shear key locations. Once a crack was formed in the shear keys, salt and water would penetrate the wearing surface and weaken the shear key grout. This brought about concerns regarding adequate load sharing among the girders and corrosion of the prestressing tendons within the girders. An extensive survey was undertaken to observe the longitudinal cracking on these bridge decks. The objectives of the field survey were to look for possible trends or relationships between various influencing parameters and the performance of these bridges. Field data were obtained from a visually selected sample survey and a comprehensive bridge record survey based on Alberta Transportation (Government of Alberta) bridge files. The parameters investigated for influence on bridge performance were span length, span width, bridge skew, service age, and traffic volume. Finally, the rehabilitation schemes used on these bridges in the past are described, and the strengths and weaknesses of each rehabilitation strategy are discussed.Key words: bridges, concrete bridges, bridge girders, load sharing, rehabilitation, shear keys, assessment, traffic loads, lateral prestressing, transverse stiffness.
Potential flow solution for a free surface flow past a sudden slope change
Authors: Zarrati A R , Jin Yee-Chung , Shanehsaz-zadeh A , Ahadi F
Published: October 2004

An analytical model was developed to calculate the pressure distribution in a free surface flow past a sudden change in channel slope. A conformal transformation technique was used to solve the problem analytically in a way that there is no need for trial and error to find the location of the free surface. Two methods were employed for this simulation: flow at a corner and free streamline theory. It was shown that free streamline theory is more accurate. Experiments were conducted to verify the ability of the analytical model to calculate the pressure distribution in a channel with a sudden change in slope. Slope changes of 6.22°, 10°, and 15° were tested with various flow discharges. The analytical model predictions of pressure distribution along the channel bed and with depth agreed well with the experimental measurements. Pressures up to 25 times the hydrostatic pressure were experimentally measured near the point of sudden change in slope. These pressures were reproduced by the model. The analytical model predictions of the water surface profile over a ramp in a prototype spillway were compared with those of a numerical model. The comparison showed a good agreement.Key words: pressure distribution, free surface flow, analytical model, chute spillway, aerator ramp, potential flow.
Suitability of mine tailings for shotcrete as a ground support
Authors: Zou D H , Sahito Wasayo
Published: October 2004

Mine tailings produced during mineral processing have traditionally been treated as a waste material and require special attention at disposal. This tradition is changing because of technology advancements and public awareness of the environmental impacts of tailings disposal on the surface. In recent years, there is an increasing trend to make the tailings a useful material. This paper presents the results of research on using the full mine tailings for shotcrete for underground support. Laboratory experiments were conducted to determine the relevant mechanical properties. Mortars made of tailings-binder mix were tested in various conditions. Sand and fibers were added to investigate their strengthening capability. This study produced valuable data. The compressive strength for the test conditions was satisfactory. The flexural strength exceeded the ASTM standards. Polymer fibers were found more effective than steel fibers as strengthening materials. Overall, this research has demonstrated the potential of mine tailings for shotcreting.Key words: mine tailings, shotcrete, compressive, flexural strength, fibers.
Numerical modelling of cohesive sediment transport in rivers
Authors: Willis David H , Krishnappan B G
Published: October 2004

Techniques available to practicing civil engineers for numerically modelling cohesive mud in rivers and estuaries are reviewed. Coupled models, treating water and sediment as a single process, remain research tools but are usually not three-dimensional. The decoupled approach, which separates water and sediment computations at each model time step, allows the three-dimensional representation of at least the bed and the use of well-proven, commercial, numerical, hydrodynamic models. Most hydrodynamic models compute sediment transport in suspension but may require modification of the dispersion coefficients to account for the presence of sediment. The sediment model deals with the sediment exchange between the water column and the bed using existing equations for erosion and deposition. Both equations relate the sediment exchange rates to the shear stress in the bottom boundary layer. In real rivers and estuaries, a depositional bed layer is associated with a period of low flow and shear, at slack tide for example, whereas in numerical models a layer is defined by the model time step. The sediment model keeps track of the uppermost layers at each model grid point, including consolidation and strengthening. Although numerical hydrodynamic models are based strongly on physics, sediment models are only numerical frameworks for interpolating and extrapolating full-scale field or laboratory measurements of "hydraulic sediment parameters," such as threshold shear stresses. Calibration and verification of models against measurement are therefore of prime importance.Key words: cohesive sediment, mathematical modelling, settling velocity, erosion, resuspension, deposition, fluid mud, bed layers.
Complex expression pattern of the Barth syndrome gene product tafazzin in human cell lines and murine tissues
Authors: Lu Biao , Kelher Marguerite R , Lee Douglas P , Lewin Tal M , Coleman Rosalind A , Choy Patrick C , Hatch Grant M
Published: October 2004

Tafazzins, a group of proteins that are defective in patients with Barth syndrome, are produced by alternate splicing of the gene G4.5 or TAZ. RT-PCR and transcription-coupled in vitro translation analysis were undertaken to determine the expression of alternatively spliced TAZ mRNA in mouse tissues and human cell lines. Only two tafazzin transcripts, both lacking exon 5, were expressed in murine tissues, whereas four tafazzin transcripts, all lacking exon 5, were observed in human umbilical vein vascular endothelial cells and U937 human monoblasts indicating a species-specific difference in the expression of TAZ mRNAs in mouse and humans. Only TAZ lacking exon 5 was expressed in murine heart. Differentiation of U937 human monoblasts into macrophages did not alter expression of the tafazzin transcripts indicating that TAZ expression is independent of monocyte differentiation. Cloning and in vitro expression of both murine and human tafazzin cDNA revealed two prominent protein bands that corresponded to the expected sizes of alternative translation. A novel fifth motif, identified as critical for the glycerolphosphate acyltransferase family, was observed in human tafazzin. The presence of a mutation in this region in Barth syndrome patients indicates that this motif is essential for tafazzin function.Key words: cardiolipin, murine, heart, Barth Syndrome, phospholipid, acyltransferase, tafazzin.
Dynamin- and clathrin-dependent endocytic pathway in unicellular eukaryoteParamecium
Authors: Wiejak Jolanta , Surmacz Liliana , Wyroba Elzbieta
Published: October 2004

The first evidence of dynamin presence and its colocalization with clathrin in the compartment involved in Paramecium receptor-mediated endocytosis is presented. We identified dynamin by cloning, Western blotting, and immunodetection in confocal and electron microscopy. The partial genes, which we have designated ParDyn1 and ParDyn2, are 1091 bp long, 90% identical to one another and encode the N-terminal and middle domains of Paramecium dynamin isoform 1 and isoform 2. The deduced amino acid sequences contain all three guanosine 5′-triphosphate (GTP)-binding motifs and show 67% homology to mammalian dynamins. Antibodies generated against the cloned GTPase domain revealed dynamin association with endosomes containing transferrin, the marker of receptor-mediated endocytosis. In Western blotting a strong immunoreactive polypeptide of ~116 kDa, which seems to be phosphorylated, was accompanied by a faint one of ~90 kDa in cytosolic fraction (S2). Dynamin level was correlated with internalization of transferrin and it was significantly decreased upon inhibition of this process. Immunogold labeling in electron microscopy revealed colocalization of dynamin and clathrin in coated pits and endocytic vesicles. Moreover, the polypeptide cross-reaction with 2 different antibodies against mammalian clathrin was identified by immunoblotting. These results indicate that dynamin- and clathrin-dependent pathway exists in this evolutionary ancient cell.Key words: dynamin, clathrin, Paramecium, endocytosis, transferrin internalization.
The motion of curling rocks: Experimental investigation and semi-phenomenological description
Authors: Jensen E T , Shegelski Mark RA
Published: October 2004

A large number of curling shots using a wide range of rotational and translational velocities on two different ice surfaces have been recorded and analyzed. The observed curling-rock trajectories are described in terms of a semi-phenomenological model. The data are found to rule out "dry-friction" models for the observed motion, and to support the idea that the curling rock rides upon a thin liquid film created at the ice surface (i.e., "wet friction"). Evidence is found to support the hypothesis that the frictional force acting upon each segment of the curling rock is directed opposite to the motion relative to this thin liquid film and not relative to the underlying fixed ice surface. PACS No.: 01.80.+b
Étude d'une décharge supersonique applicable au traitement des effluents gazeux
Authors: Pellerin S , Chapelle J
Published: October 2004

The use of sliding discharge in air is characterized by the emission of important quantities of nitrogen oxides NOx. We have shown that the utilization of convergent-divergent Laval's nozzle working in supersonic air flow offered the possibility to obtain, from the atmospheric pressure and with high gas flow rate, cold plasmas of interest for different industrial applications, without production of NOx. The very turbulent region of the shockwave, can present a great interest for the mix and the interaction of reactive species formed in the uphill flow.
Geotechnical survey and mechanical parameters in urban soils: modelling soil variability and inferring representative values using the extension of Lyon subway line D as a case study
Authors: Emeriault F , Breysse D , Kastner R , Denis A
Published: October 2004

Urban soils are generally heterogeneous and thus require, for any project, careful geotechnical evaluation. Considering the difficulty faced by geotechnical engineers in defining a model of the underground (different soil layers and associated physical-mechanical properties), it appears useful to clearly define a strategy for the analysis of the site investigation results. As well as an in-depth knowledge of the site, this strategy should rely on carefully defined general rules of analysis and treatment of collected data. The processes leading to a representative and accurate model of the volume of soil affected by the underground works are identified in this paper based on the analysis of a case study (extension of the Lyon subway line D). Variability is one of the main features of urban soils, therefore one should be able to quantify and compare this variability with other sources of uncertainties and inaccuracies affecting the design process, such as the quality of measurements and numerical modelling errors. New design codes based on the concept of representative material properties (i.e., Eurocode characteristic values) imply the need for a risk-oriented analysis of the reconnaissance results.Key words: urban soil, underground construction, data analysis, representative value, geotechnical survey, variability.
Stressdilatancy in very loose sand
Authors: Been Ken , Jefferies Michael
Published: October 2004

Virtually all investigation of liquefaction has used undrained tests, and it has become common to represent the undrained strength in terms of a collapse surface or collapse stress ratio described by an effective friction angle. A difficulty with undrained tests is that they only allow observation of the interaction of elastic and plastic strain because of the imposed boundary condition (i.e., no drainage or zero volume change), precluding a proper understanding of an effective stress criterion for maximum undrained strength. Drained triaxial tests do not suffer from this shortcoming, and stressdilatancy of dense sands in drained shear is well established as a fundamental aspect of sand behaviour, based on micromechanical considerations. It is particularly interesting to consider the stressdilatancy behaviour of very loose sands in the context of soil liquefaction. Although there are some data in the literature on loose sand behaviour in drained triaxial compression, the majority of data are actually for sands markedly denser than sands showing static liquefaction in undrained tests. This paper therefore reports some laboratory testing of very loose sands, together with comparative undrained liquefaction data, and compares the loose behaviour to that of dense sand. These data are reduced to stressdilatancy form so that the fundamental aspects of loose soil behaviour can be seen and compared to flow rules used in constitutive models. The stressdilatancy of very loose sand shows no limiting stress ratio markedly less than that of the critical state. Moreover, the stressdilatancy trends of very loose sand are the same as those of dense sand. There is no evidence of "structural collapse" of the particulate arrangement of very loose sands, contrary to speculation associated with collapse surfaces in the literature. Explanations of sand liquefaction must seek other physical explanations of the soil behaviour.Key words: sand, constitutive relations, plasticity, liquefaction.
Numerical model verification and calibration of George Massey Tunnel using centrifuge models
Authors: Yang Dan , Naesgaard Ernest , Byrne Peter M , Adalier Korhan , Abdoun Tarek
Published: October 2004

Dynamic soilstructure interaction analyses were carried out for the seismic retrofit design of the immersed George Massey Tunnel, both to predict and study soil liquefaction and related tunnel movements and to design ground improvement. The proposed ground improvement included ground densification using vibroreplacement stone columns along both sides of the tunnel and seismic gravel drains adjacent to the outer edge of the densified zones. The den sification and drainage were proposed to locally mitigate soil liquefaction and reduce displacements of the tunnel to tolerable levels. Centrifuge model tests with base shaking to simulate earthquake effects were conducted to verify and calibrate the numerical models. This included simulating the effects of ground densification and drainage on reme diating tunnel movements. This paper presents the principal results from the dynamic analyses, the centrifuge model design and testing procedure, the class A predictions of the centrifuge tests, and discussions of the centrifuge test results and numerical model calibrations.Key words: immersed tunnel, seismic retrofit, soil liquefaction, design verification, centrifuge testing, numerical calibration.
The persistence of a large stagnation zone in a developed regional aquifer, southwestern Ontario
Authors: Husain Muin M , Cherry John A , Frape Shaun K
Published: October 2004

An extensive groundwater zone of exceptionally negative δ18O (17.5 to 16.0) exists in a thin, regional, freshwater aquifer between Lake St. Clair and the southern shore of Lake Huron in southwestern Ontario. The zone occurs at the interface between the overlying thick Quaternary clay aquitard of glaciolacustrine origin and the underlying bedrock shale. This isotope signature, which is 7 more negative (lighter) than modern water, indicates a Late Pleistocene origin of the aquifer water. This zone occurs only where the Quaternary aquitard is greater than 35 m thick. In the Quaternary aquitard, the Pleistocene isotope signature extends upward from the aquifer and then has a gradational transition to signature resembling modern water (10) near the ground surface. This regional-scale study of the aquiferaquitard system indicates that the pattern of flow of the aquifer has allowed the persistence of the Pleistocene groundwater since the aquitard was deposited approximately 10 000 years before present. As part of the regional study, a two-dimensional groundwater flow model was used to assess the origin and persistence of the Pleistocene zone under natural conditions. The persistence of the Pleistocene zone was also assessed based on water budgets prepared from aquifer use history and aquiferaquitard parameters. Our study finds that the low yield and poor quality of groundwater in this zone have caused minimal use, resulting in the persistence of the Pleistocene groundwater since the beginning of major aquifer use in the 1940s.Key words: regional aquifer, aquitard, Pleistocene water, stagnation, aquifer use.
MICROBEAM ANALYSIS SYSTEM AT TOHOKU UNIVERSITY
Authors: MATSUYAMA S. , ISHII K. , YAMAZAKI H. , BARBOTTEAU Y. , AMARTAIVAN TS. , IZUKAWA D. , HOTTA K. , MIZUMA K. , ABE S. , OHISHI Y. , RODRIGUEZ M. , SUZUKI A. , SAKAMOTO R. , FUJISAWA M. , KAMIYA T. , OIKAWA M. , ARAKAWA K. , IMASEKI H. , MATSUMOTO N.
Published: October 2004

A microbeam analysis system has been developed at Tohoku University for biological applications. Spatial resolution of less than 1 μm has been achieved with a beam current of ~40 pA. In microbeam analysis of biological specimens, simultaneous measurement of structural and elemental properties is very important. Our system is applicable to simultaneous in-air/vacuum PIXE, RBS and STIM analyses. Typical results of biological application are shown.
PRECOMPACTNESS OF THE CALABI ENERGY
Authors: SIMANCA SANTIAGO R.
Published: October 2004

For any complex manifold of Kähler type, the L2-norm of the scalar curvature of an extremal Kähler metric is a continuous function of the Kähler class. In particular, if a convergent sequence of Kähler classes are represented by extremal Kähler metrics, the corresponding sequence of L2-norms of the scalar curvatures is convergent. Similarly, the sequence of holomorphic vector fields associated with a sequence of extremal Kähler metrics with converging Kähler classes is convergent.
EINSTEIN-WEYL DEFORMATIONS AND SUBMANIFOLDS
Authors: PEDERSEN HENRIK , POON YAT SUN , SWANN ANDREW
Published: October 2004

Motivated by new explicit positive Ricci curvature metrics on the four-sphere which are also Einstein-Weyl, we show that the dimension of the Einstein-Weyl moduli near certain Einstein metrics is bounded by the rank of the isometry group and that any Weyl manifold can be embedded as a hypersurface with prescribed second fundamental form in some Einstein-Weyl space. Closed four-dimensional Einstein-Weyl manifolds are proved to be absolute minima of the L2-norm of the curvature of Weyl manifolds and a local version of the Lafontaine inequality is obtained. The above metrics on the four-sphere are shown to contain minimal hypersurfaces isometric to S1×S2 whose second fundamental form has constant length.
MARKET DEPTH AND PRICE DYNAMICS: A NOTE
Authors: WESTERHOFF FRANK H.
Published: October 2004

This note explores the consequences of nonlinear price impact functions on price dynamics within the chartist–fundamentalist framework. Price impact functions may be nonlinear with respect to trading volume. As indicated by recent empirical studies, a given transaction may cause a large (small) price change if market depth is low (high). Simulations reveal that such a relationship may create endogenous complex price fluctuations even if the trading behavior of chartists and fundamentalists is linear.
Measurement of Subcutaneous Impedance by Four-Electrode Method at Acupoints Located with Single-Power Alternative Current
Authors: Zhang Wei-Bo , Jeong Dong-Myong , Lee Yong-Heum , Lee Myeong Soo
Published: October 2004

A Single-Power Alternating Current (SPAC) instrument was used to measure the low-impedance acupoints around Ho-Ku (LI-4), Yang-Hsi (LI-5), Yang-Ch'ih (TB-4), Yang-Ku (SI-5), T'ai-Yuan (Lu-9), Ta-Lung (EH-7) and Shen-Men (He-7). A four-electrode instrument was used to measure the subcutaneous impedance at these low-impedance acupoints and adjacent control points on 12 healthy people. The mean subcutaneous impedance at the acupoints was 49.8±8.4 Ω, significantly lower than the impedance of 53.5±9.3 Ω for the control points (P<0.005). Of the seven acupoints, five (71%) had significantly lower impedances than the mean impedance for the adjacent control points. Seven of the 14 control points had significantly higher impedances than the adjacent acupoints, with most control points (93%) having higher impedances than adjacent acupoints. In conclusion, subcutaneous impedance is lower at the low-impedance points as measured with the SPAC two-electrode method. One interpretation of these results is that more interstitial fluid lies beneath the low-impedance acupoints.
Antioxidant Activity of Porcelainberry (Ampelopsis brevipedunculata(Maxim.) Trautv.)
Authors: Wu Ming-Jiuan , Yen Jui-Hung , Wang Lisu , Weng Ching-Yi
Published: October 2004

The stem and root of Porcelainberry (Ampelopsis brevipedunculata (Maxim.) Trautv.) (AB) was traditionally used as an anti-inflammatory, diuretic and anti-hepatotoxic agent in folk medicine. In this study, cell-free and cell culture systems were employed to investigate the antioxidant activity of the methanol extract of AB (MEAB). The cell-free system showed that the MEAB exhibited dose-dependent antioxidant activities against linoleic acid peroxidation and plasmid DNA oxidation. We also demonstrated that the MEAB possessed strong reducing power and scavenging effects of hydroxyl radicals and DPPH free radicals.

The harmful effects of reactive oxygen metabolites on HepG2 cells and the possible antioxidant effects of the MEAB were also investigated. Pretreatment or cotreatment of HepG2 cells with the MEAB could significantly protect cells from H 2 O 2-induced oxidative stress. This implies that the antioxidant effects in cell culture may result from the direct interaction between the MEAB and exogenous oxidant sources, as these occur in cell free systems, as well as from the induction of cellular stress gene expression. The antioxidant activity of the MEAB may partially explain its anti-inflammatory and anti-hepatotoxic effects.
SELF-LENSING EFFECTS FOR COMPACT STARS AND THEIR MASS–RADIUS RELATION
Authors: PRASANNA A. R. , RAY SUBHARTHI
Published: October 2004

During the last couple of years astronomers and astrophysicists have been debating on the fact whether the so-called "strange stars" — stars made up of strange quark matter, have been discovered with the candidates like SAX J1808.4–3658, 4U 1728–34, RX J1856.5–3754, etc. The main contention has been the estimation of radius of the star for an assumed mass of ~ 1.4 M⊙ and to see whether the point overlaps with the graphs for the neutron star equation of state or whether it goes to the region of stars made of strange matter equation of state. Using the well-established formulae from general relativity for the gravitational redshift and the "lensing effect" due to bending of photon trajectories, we, in this letter, relate the parameters M and R with the observable parameters, the redshift z and the radiation radius R∞, thus constraining both M and R for specific ranges, without any other arbitrariness. With the required inputs from observations, one ought to incorporate the effects of self-lensing of the compact stars which has been otherwise ignored in all of the estimations done so far. Nonetheless, these effects of self-lensing make a marked difference for constraints on the M–R relation.
FORMATION OF WAKES BY CHIRAL CONDUCTING COSMIC STRINGS
Authors: ABDALLA M. C. B. , BYTSENKO A. A. , GUIMARÃES M. E. X.
Published: October 2004

Chiral cosmic strings are naturally produced at the end of D-term inflation and they present very interesting cosmological consequences. In this work, we investigate the formation and evolution of wakes by a chiral string. We show that, for cold dark matter, the mechanism of forming wakes by a chiral string is similar to the mechanism by an ordinary string.
NONCOMMUTATIVE MODULI FOR MULTI-INSTANTONS
Authors: IVANOVA TATIANA A. , LECHTENFELD OLAF , MÜLLER-EBHARDT HELGE
Published: October 2004

There exists a recursive algorithm for constructing BPST-type multi-instantons on commutative ℝ4. When deformed noncommutatively, however, it becomes difficult to write down non-singular instanton configurations with topological charge greater than one in explicit form. We circumvent this difficulty by allowing for the translational instanton moduli to become noncommutative as well. Such a scenario is natural in the self-dual Yang–Mills hierarchy of integrable equations where the moduli of solutions are seen as extended spacetime coordinates associated with higher flows. By judicious adjustment of the moduli-noncommutativity we achieve the ADHM construction of generalized 't Hooft multi-instanton solutions with everywhere self-dual field strengths on noncommutative ℝ4.
DIMENSIONAL REDUCTION OF QUANTUM FIELDS ON A BRANE
Authors: HABA Z.
Published: October 2004

A singular metric arising in some brane models can substantially influence the behavior of Green's functions. We show that the quantum scalar field defined by a restriction of the Green's function to the brane can behave as a canonical quantum field living on the lower dimensional submanifold.
PARTITION FUNCTIONS OF MATRIX MODELS: FIRST SPECIAL FUNCTIONS OF STRING THEORY
Authors: ALEXANDROV A. , MOROZOV A. , MIRONOV A.
Published: October 2004

Even though matrix model partition functions do not exhaust the entire set of τ-functions relevant for string theory, they seem to be elementary building blocks for many others and they seem to properly capture the fundamental symplicial nature of quantum gravity and string theory. We propose to consider matrix model partition functions as new special functions. Here we restrict our consideration to the finite-size Hermitian 1-matrix model and concentrate mostly on its phase/branch structure arising when the partition function is considered as a D-module. We discuss the role of the CIV–DV prepotential (as generating a possible basis in the linear space of solutions to the Virasoro constraints, but with a lack of understanding of why and how this basis is distinguished).
GENERALIZED SCHRÖDINGER EQUATION IN EUCLIDEAN FIELD THEORY
Authors: CONRADY FLORIAN , ROVELLI CARLO
Published: October 2004

We investigate the idea of a "general boundary" formulation of quantum field theory in the context of the Euclidean free scalar field. We propose a precise definition for an evolution kernel that propagates the field through arbitrary space–time regions. We show that this kernel satisfies an evolution equation which governs its dependence on deformations of the boundary surface and generalizes the ordinary (Euclidean) Schrödinger equation. We also derive the classical counterpart of this equation, which is a Hamilton–Jacobi equation for general boundary surfaces.
COMPUTATIONAL CONSIDERATIONS IN THE CALCULATION OF THE CASIMIR FORCE BETWEEN MULTILAYERED SYSTEMS
Authors: PINTO FABRIZIO
Published: October 2004

It is shown that, in contrast to the case of two semi-infinite slabs, the Casimir force between two periodic multilayer stacks cannot be computed by means of the typical Lifshitz integration along the imaginary frequency axis because both the integrand and the reflectivity coefficients display multiple poles on such axis. Consequently, all objections to the possibility of radically engineering the magnitude, gap width dependence, and sign of the Casimir force, which were based upon such invalid expressions, are removed. Some experimental and computational implications of these results are discussed.
THEORY OF THE THREE-GROUP EVOLUTIONARY MINORITY GAME
Authors: CHEN KAN , WANG BING-HONG , YUAN BAOSHENG
Published: October 2004

Based on the general adiabatic theory for the evolutionary minority game (EMG) that we proposed earlier,1 we perform a detail analysis of the EMG limited to three groups of agents. We derive a formula for the critical point of the transition from segregation (into opposing groups) to clustering (towards cautious behaviors). Particular to the three-group EMG, the strategy switching in the "extreme" group does not occur at every losing step and is strongly intermittent. This leads to an correction to the critical value of the number of agents at the transition, Nc. Our expression for Nc is in agreement with the results obtained from our numerical simulations.
STATE EVOLUTION AND INFORMATION PROCESSING IN Mn12 QUANTUM MAGNET
Authors: ZHOU BIN , TAO RUIBAO , SHEN SHUN-QING
Published: October 2004

Following an alternative version of Grover's algorithm, we propose a scheme to read- in information in Mn 12 molecular magnets with the help of multi-frequency magnetic pulses in two separate steps: first to realize an intermediate state |Ψ(T1)> and then to reach the state |Ψ(T2)> to encode information. All controllable parameters are calculated to implement read-in of information, and the durations of magnetic pulses are less than the dephasing time of quantum states in Mn 12. It is also shown that all the states of information can be initialized back to the intermediate state.
FROM NEW FUNDAMENTAL EQUATION OF STATISTICAL PHYSICS TO THE FORMULA FOR ENTROPY PRODUCTION RATE
Authors: XING XIU-SAN
Published: October 2004

Why the classical mechanics and quantum mechanics are reversible while the macroscopic thermodynamic processes are irreversible? Is it because both of the two are different fundamental laws? If yes, what is the difference between them? What is the fundamental equation of nonequilibrium statistical physics? Can it provide a unified framework of statistical physics including nonequilibrium states and equilibrium states? How can we derive rigorously the hydrodynamic equations from microscopic kinetics? Does nonequilibrium entropy obey any evolution equation? What is the form of this equation if it exist? What is the microscopic physical basis of entropy production rate namely the law of entropy increase? Can it be described by a quantitative concise formula? What mechanism is responsible for the processes of approach to equlibrium? How to quantitatively describe it? In this paper we try to solve all these problems from a new fundamental equation of statistical physics in a unified fasion.
SCALING PROPERTY OF THE DILUTE-DENSE TRANSITION IN 2D GRANULAR FLOWS
Authors: HOU MEIYING , CHEN WEI , ZHANG TONG , LU KUNQUAN , CHAN C. K.
Published: October 2004

In this paper we report our experimental study of dilute-dense transition in a 2-dimensional granular flow of particle size d0 and channel width D with confined exit of width d. It is found that a maximum inflow rate Qc exists, above which the outflow changes from dilute to dense and the outflow rate Q(t) drops abruptly from Qc to a dense flow rate Qd. The re-scaled critical rate qc(≡Qc/(D/d0)) is found to be a function of a scaling variable λ only, i.e. qc~F(λ), and [Formula: see text]. The form of this new variable λ suggests that the dilute-to-dense transition is a global property of the flow; unlike the jamming transition, which depends only on [Formula: see text]. It is also found that this transition occurs when the area fraction of particles near the exit reaches a critical value 0.65±0.03.
STATISTICAL PROPERTIES OF THE ADDITIVE AUTOMATON NETWORKS
Authors: GU G. Q.
Published: October 2004

A set of theorems about the evolutionary properties of the automaton networks are presented in this article, which includes the theorems that, for an additive automaton network, the tree structures are identical, and that the geometric entropy equals to its topological entropy. The exact analytical formula for the entropy of the additive automaton networks is introduced, and applied to investigate the evolutionary properties of the elementary cellular automata of number 90 and number 150.
NETWORK OF ECONOPHYSICISTS: A WEIGHTED NETWORK TO INVESTIGATE THE DEVELOPMENT OF ECONOPHYSICS
Authors: FAN YING , LI MENGHUI , CHEN JIAWEI , GAO LIANG , DI ZENGRU , WU JINSHAN
Published: October 2004

The development of Econophysics is studied from the perspective of scientific communication networks. Papers in Econophysics published from 1992 to 2003 are collected. Then a weighted and directed network of scientific communication, including collaboration, citation and personal discussion, is constructed. Its static geometrical properties, including degree distribution, weight distribution, weight per degree, and betweenness centrality, give a nice overall description of the research works. The way we introduced here to measure the weight of connections can be used as a general one to construct weighted network.
NON-CLASSICAL QUANTUM CORRELATIONS IN QUANTUM GAMES
Authors: DU JIANGFENG , CHENG GUANGLEI , LI HUI
Published: October 2004

In this paper we propose an interesting scheme for quantum games. It is found that, for the particular case of the famous Prisoners' Dilemma game, the superiority of the quantum game over its classical counterpart is interconnected to the non-classical quantum correlation between the two players.
STRANGE REPELLER'S CRISIS IN SOME NON-SMOOTH SYSTEMS
Authors: WANG WEN-XIU , HE YUE , SHEN YING , LU YUN-QING , HE DA-REN
Published: October 2004

A new kind of crisis is defined as a sudden change of a strange repeller. It can be observed in some non-smooth systems, such as a tent map, a "hole map", an electronic relaxation oscillator, and a discontinuous kicked rotor.
CONTROLLING CHAOS AND HYPERCHAOS BY SWITCHING MODULATION OF SYSTEMS PARAMETERS
Authors: LUO XIAO-SHU , WANG BING-HONG , CHEN GUAN-RONG , JIANG PIN-QUN , FANG JIN-QING , QUAN HONG-JUN
Published: October 2004

In this paper, a new strategy is developed for controlling chaos and hyperchaos in a nonlinear system via switching modulation of systems parameters. The control method is illustrated by examples of the third-order chaotic Chua's circuit and a sixth-order coupled hyperchaotic Chua's circuit. Numerical simulations show that this method is very effective.
MODELING STOCK MARKET BASED ON GENETIC CELLULAR AUTOMATA
Authors: ZHOU TAO , ZHOU PEI-LING , WANG BING-HONG , TANG ZI-NAN , LIU JUN
Published: October 2004

An artificial stock market is established with the modeling method and ideas of cellular automata. Cells are used to represent stockholders, who have the capability of self-teaching and are affected by the investing history of the neighboring ones. The neighborhood relationship among the stockholders is the expanded Von Neumann relationship, and the interaction among them is realized through selection operator and crossover operator. Experiment shows that the large events are frequent in the fluctuations of the stock price generated by the artificial stock market when compared with a normal process and the price returns distribution is a Lévy distribution in the central part followed by an approximately exponential truncation.
LATTICE BOLTZMANN SIMULATION OF A SINGLE CHARGED ELLIPTIC CYLINDER IN A NEWTONIAN FLUID
Authors: ZHANG CAOYING , TAN HUILI , LIU MUREN , KONG LINGJIANG , FANG HAIPING
Published: October 2004

A two-dimensional dynamics model of an elliptic cylinder is derived by using the lattice Boltzmann method. With the present model, we have simulated the sedimentation of a single charged elliptic cylinder in a two-dimensional tube in a Newtonian fluid. Due to the polarizing effects and non-axial symmetry shape, there are the Coulomb force and the Coulomb torque on the elliptic cylinder during the sedimentation, which change its ordinary motion significantly. Comparing with the sedimentation of an un-charged elliptic cylinder under the same initial condition, we have further discussed the dynamics characteristics of the charged elliptic cylinder, and obtained some interesting results.
ELECTRON–ELECTRON INTERACTIONS IN THE QUANTUM DOT INDUCED BY THE SURFACE ACOUSTIC WAVE
Authors: WANG ZHENG-CHUAN , LI LING , GAO JIE
Published: October 2004

In order to study the higher order quantized plateaus in the acoustoelectric current induced by the surface acoustic wave (SAW), we consider in this paper, the Coulomb interaction of electrons trapped in the SAW-induced quantum dot at the Hartree approximation level. The Hartree self-consistent potential that originates from the electron–electron interactions in the quantum dot satisfies the Poisson equation and can be solved numerically together with the Schrödinger equation; following which, the conventional tunneling mechanism can be used to interpret the step-like acoustoelectric current, in which the escape of electrons from the quantum dot determines the deviation of the current from the quantized value. It should be noted that the quantum dot is formed by both the SAW-induced potential and the Hartree self-consistent potential in our paper, which is different from previous works. We have also calculated the first and the second quantized plateaus by use of this method.
EVALUATION OF Sr2YSbO6 AS A NEW SUBSTRATE FOR YBa2Cu3O7-δ SUPERCONDUCTOR THIN FILMS
Authors: ORTIZ DIAZ O. , ROA-ROJAS J. , LANDÍNEZ TÉLLEZ D. A. , ALBINO AGUIAR J.
Published: October 2004

A complex perovskite oxide Sr 2 YSbO 6 has been synthesized by solid-state reaction. X-ray diffraction (XRD) pattern reveals that Sr 2 YSbO 6 has an ordered complex cubic structure characteristic of A 2 BB ' O 6 crystalline structure with lattice constant a=8.2561 Å which has a fairly good lattice matching (lattice mismatch of the order of 8%) with YBa 2 Cu 3 O 7-δ. Energy dispersive X-ray (EDX) analysis shows that Sr 2 YSbO 6 is free of impurity traces. The chemical stability of Sr 2 YSbO 6 with YBa 2 Cu 3 O 7-δ superconducting has been studied by X-ray diffraction and magnetic measurements on Sr 2 YSbO 6– YBa 2 Cu 3 O 7-δ composites. XRD patterns of the composite show that all the XRD peaks could be indexed for either Sr 2 YSbO 6 or YBa 2 Cu 3 O 7-δ with no extra peak detectable. This implies that YBa 2 Cu 3 O 7-δ and Sr 2 YSbO 6 remain as two different separate phases in the composite with no chemical interaction. Magnetic measurements show that superconducting transition temperature of pure YBa 2 Cu 3 O 7-δ and Sr 2 YSbO 6– YBa 2 Cu 3 O 7-δ composites is 90 K. These favorable characteristics of Sr 2 YSbO 6 show that it can be used as a potential substrate material for fabrication of YBa 2 Cu 3 O 7-δ superconducting films.
ANOMALOUS FREQUENCY DEPENDENCE OF DIFFERENTIAL MOBILITY IN SUPERLATTICE MINIBAND TRANSPORT
Authors: LEI X.L. , HORING N.J.M. , CUI H.L. , THORNBER K.K.
Published: October 2004

We examine the frequency-dependence of carrier drift-velocity in superlattice miniband conduction for a small signal ac electric field superposed on a dc bias E0. Our determination of the differential mobility is based on an accurate microscopic treatment of phonon and impurity scatterings. At finite E0, the differential mobility exhibits anomalous frequency-dependence: its real part exhibits a broad hump before finally approaching zero at high frequency, and its imaginary part has a marked dip to negative values before going through the conventional maximum. A simple dual-parameter empirical formula adapted from velocity overshoot studies provides excellent fits to this unusual behavior.
A STUDY OF PHOTOACOUSTIC EFFECTS AND OPTICAL LIMITING IN THE SOLUTION OF C60 IN TOLUENE
Authors: ISSAC RIJU C. , BINDHU C.V. , HARILAL S.S. , VARIER GEETHA K. , NAMPOORI V.P.N. , VALLABHAN C.P.G.
Published: October 2004

Pulsed photoacoustic studies in solution of C 60 in toluene have been made using the 532 nm radiation from a frequency doubled Nd:YAG laser. Though C 60 is found to exhibit the phenomenon of optical limiting, the results on photoacoustic measurements do not give any indication of multiphoton transitions as suggested in some of the earlier works. Results of photoacoustic measurements show that excited state absorption is the dominant process responsible for optical limiting while phenomena like nonlinear scattering may contribute to a lesser extent.