bluuebunny/crossref_metadata_2025 huggingface dataset:
Primary prevention of sexually transmitted disease: applying the ABC strategy
Authors: Genuis S J , Genuis S K
Published: May 2005

Escalating rates of sexually transmitted disease (STD) in many areas of the world necessitate a re-evaluation of current public health STD preventive programmes. Pervasive long term sequelae for many STD afflicted people and the emerging threat, caused by the HIV/AIDS pandemic, to some national infrastructures, suggests that ongoing initiatives focusing primarily on risk reduction through barrier protection have not met their desired objective. Recent strategies to promote non-coital sexual involvement as a means of achieving STD reduction fail to address the transmission of infection that may occur through alternative non-intercourse sexual activities. The demonstrated success of the innovative, comprehensive ABC strategy shows that while risk reduction and treatment of existing infection remain important, the promotion of optimal health may be achieved more effectively through broad based comprehensive and adaptable programmes that include an emphasis on risk avoidance through delayed sexual debut and partner reduction.
Management of epilepsy in women
Authors: O’Brien M D , Gilmour-White S K
Published: May 2005

There are many aspects to the management of epilepsy in women related to their role in reproduction. Some of these need to be considered in adolescents, some are related to pregnancy, concerning both the mother and her infant, and others with the menstrual cycle and the menopause. This review considers contraception, fertility, teratogenicity, and the use of folic acid. It also discusses the special investigations in pregnancy, hyperemesis, the effect of pregnancy on the control of epilepsy, the effect of seizures on the fetus, a first fit in pregnancy, pseudoseizures, seizures during delivery, vitamin K, breast feeding, postpartum maternal epilepsy, hereditary risks, counselling, catamenial epilepsy, the menopause, and bone density.
Partial reversal by rutin and quercetin of impaired cardiac function in streptozotocin-induced diabetic rats
Authors: Krishna Kota M , Annapurna Akula , Gopal Gopisetty S , Chalam Chitrapu R.V , Madan Kalagara , Kumar Veeravalli K , Prakash Gomedhikam J
Published: May 2005

The present investigation was carried out to evaluate the effects of the cyclodextrin complexes quercetin and rutin on left ventricle dysfunction in streptozotocin-induced diabetic rats. Diabetes was induced by streptozotocin (45 mg/kg body mass, i.v.) in Sprague–Dawley rats. Echocardiography and biochemical and histological studies were carried out under normal control, diabetic untreated, normal and diabetic vehicle (β-cyclodextrin, p.o.), quercetin- (100 and 300 mg/kg, p.o.), and rutin- (100 and 300 mg/kg, p.o.) treated normal and diabetic animals at varying time intervals (1 and 12 weeks). The increase in the serum triglycerides and cholesterol levels was attenuated in the cyclo dextrin complexes of rutin-treated animals significantly more than in the quercetin-treated and diabetic vehicle-treated animals. Left ventricular diastolic dysfunction was observed in diabetic vehicle-treated animals after 12 weeks of the study as determined by a significant decrease in E-wave (45.91%), an increase in the A-wave (75.55%), and a decrease in the E/A ratio (70.14%). However, the percent decrease (after 12 weeks) in the E-wave, increase in the A-wave, and decrease in the E/A ratio were less in the cyclodextrin complexes of rutin-treated animals (100 and 300 mg/kg), which had the following values: E-wave, 12.22% and 13.80%; A-wave, 25.90% and 10.40%; and E/A ratio, 31.01% and 20.52%. In the quercetin-treated animals (100 and 300 mg/kg), which had the following values: E-wave, 40.44% and 36.44%; A-wave, 52.98% and 29.28%; and E/A ratio, 61.70% and 51.11%. Histopathological studies revealed that the degree of myocardial necrosis was less in rutin-treated animals compared with quercetin and diabetic vehicle-treated animals: rutin < quercetin < β-cyclodextrin. Myocardial fructose levels were significantly increased in the diabetic vehicle-treated animals after 12 weeks of the study, suggesting an increment in the myocardial polyol pathway activity. However, myocardial fructose levels were significantly decreased in the rutin- and quercetin-treated animals compared with the vehicle-treated animals, possibly owing to their aldose reductase inhibitory activity. Quercetin and rutin treatment did not influence the echocardiographical and histo logical parameters in normal animals. Results from the present investigation demonstrated that rutin has a cardioprotective activity, and we conclude that the observed cardioprotection with rutin may be due to its aldose reductase inhibitory activity, as the enhanced aldose reductase pathway is implicated in the development of left ventricle dysfunction by several studies.Key words: aldose reductase inhibitors, bioflavonoids, diabetic cardiomyopathy, myocardial fructose, polyol pathway.
Alpha 1 adrenergic receptor control of renal blood vessels during aging
Authors: Passmore John C , Rowell Peter P , Joshua Irving G , Porter James P , Patel Divyan H , Falcone Jeff C
Published: May 2005

Aging humans and rats have a reduced renal vascular constriction response to stress, change in posture, or exercise. In this study, renal interlobar arteries from 9- (intermediate age) to 15-month-old (aging) male Wistar rats constricted less to alpha-adrenergic agonists than those of 4-month-old (young adult) rats. The reduced contraction to A61603 (alpha 1 A agonist) was similar to that to norepinephrine and phenylephrine. Therefore, it appears that the reduction in constriction is primarily related to alpha 1 A receptor stimulation. GeneChip microarray hybridization analysis of the interlobar arteries with the RAE 230A GeneChip indicated that there were no significant differences in gene expression for alpha 1 A/C, 1B, or 1D receptors between 4-month-old (young adult) and 1-year-old (aging) male Wistar rats. Competitive binding experiments (prazosin) revealed that maximal binding (Bmax, fmol/mg protein) of the alpha 1 receptors of interlobar arteries was reduced 25% by 10 months of age and 50% by 18+ months of age. Alpha 1 receptor-induced arterial constriction and prazosin binding were both down-regulated. The loss of receptor-initiated constriction likely includes down-regulation of maximum agonist binding by alpha 1 adrenergic receptors.Key words: kidney, stress, blood flow, male vs. female, GeneChip array, prazosin.
Modification of sarcoplasmic reticulum (SR) Ca2+release by FK506 induces defective excitation-contraction coupling only when SR Ca2+recycling is disturbed
Authors: Yoshihara Shu , Satoh Hiroshi , Saotome Masao , Katoh Hideki , Terada Hajime , Watanabe Hiroshi , Hayashi Hideharu
Published: May 2005

This study examined whether the effects of FK506-binding protein dissociation from sarcoplasmic reticulum (SR) Ca2+release channels on excitation-contraction (EC) coupling changed when SR Ca2+reuptake and (or) the trans-sarcolemmal Ca2+extrusion were altered. The steady-state twitch Ca2+transient (CaT), cell shortening, post-rest caffeine-induced CaT, and Ca2+sparks were measured in rat ventricular myocytes using laser-scanning confocal microscopy. In the normal condition, 50 µmol FK506/L significantly increased steady-state CaT, cell shortening, and post-rest caffeine-induced CaT. When the cells were solely perfused with thapsigargin, FK506 did not reduce any of the states, but when low [Ca2+]0(0.1 mmol/L) was perfused additionally, FK506 reduced CaT and cell shortening, and accelerated the reduction of post-rest caffeine-induced CaT. FK506 significantly increased Ca2+spark frequency in the normal condition, whereas it mainly prolonged duration of individual Ca2+sparks under the combination of thapsigargin and low [Ca2+]0perfusion. Modification of SR Ca2+release by FK506 impaired EC coupling only when released Ca2+could not be taken back into the SR and was readily extruded to the extracellular space. Our findings could partly explain the controversy regarding the contribution of FK506-binding protein dissociation to defective EC coupling.Key words: FK506, ryanodine receptor, sarcoplasmic reticulum Ca2+-ATPase, Na+/Ca2+exchange, excitation-contraction coupling
Acetylcholine-induced phosphorylation of CPI-17 in rat bronchial smooth muscle: the roles of Rho-kinase and protein kinase C
Authors: Sakai Hiroyasu , Hirano Tomona , Takeyama Hisao , Chiba Yoshihiko , Misawa Miwa
Published: May 2005

It has been demonstrated that CPI-17 provokes an inhibition of myosin light chain phosphatase to increase myosin light chain phosphorylaton and Ca2+sensitivity during contraction of vascular smooth muscle. However, expression and agonist-mediated regulation of CPI-17 in bronchial smooth muscle have not been documented. Thus, expression and phosphorylation of CPI-17 mediated by PKC and ROCK were investigated using rat bronchial preparations. Acetylcholine (ACh)-induced contraction and Ca2+sensitization were both attenuated by 10–6mol Y-27632 /L, a ROCK inhibitor, 10–6mol calphostin C/L, a PKC inhibitor, and their combination. A PKC activator, PDBu, induced a Ca2+sensitization in α-toxin-permeabilized bronchial smooth muscle. In this case, the Ca2+sensitizing effect was significantly inhibited by caphostin C but not by Y-27632. An immunoblot study demonstrated CPI-17 expression in the rat bronchial smooth muscle. Acetylcholine induced a phosphorylation of CPI-17 in a concentration-dependent manner, which was significantly inhibited by Y-27632 and calphostin C. In conclusion, these data suggest that both PKC and ROCK are involved in force development, Ca2+sensitization, and CPI-17 phosphorylation induced by ACh stimulation in rat bronchial smooth muscle. As such, RhoA/ROCK, PKC/CPI-17, and RhoA/ROCK/CPI pathways may play important roles in the ACh-induced Ca2+sensitization of bronchial smooth muscle contraction.Key words: CPI-17, bronchial smooth muscle, acetylcholine, ROCK, protein kinase C.
QUANTUM THERMAL EFFECT OF ARBITRARILY ACCELERATING KERR BLACK HOLE
Authors: YANG XUEJUN , ZHENG ZHAO
Published: May 2005

By introducing a new Tortiose coordinate and using the notion of local equilibrium, we have studied the Hawking effect and the entropy of an arbitrarily accelerating Kerr black hole, a nonstationary black hole. The Bekenstein–Hawking entropy has been obtained by taking the same geometric cutoff relationship in the thin film model as that in the static case. Consequently, the results in the new Tortiose coordinate reveal the following two facts. First, it is correct in the opinion that the black hole entropy is determined by the horizon of a black hole, whether it is stationary or nonstationary. Second, the entropy of the nonstationary black hole shows some common essential natures with that of a static one.
N = 2 SUPERSYMMETRIES FOR QUANTUM STATES OF THE 1D WOODS–SAXON AND PERIODIC SCARF POTENTIALS
Authors: CHENAGHLOU A. , FAKHRI H.
Published: May 2005

In addition to obtain ordinary SUSY representation related to the partner Hamiltonians, three other nonordinary SUSY representations for the quantum states of 1D Woods–Saxon and periodic Scarf potentials are obtained by the factorization methods. The ordinary SUSY representation induces laddering relations for these two models with respect to the parameters n and m that are introduced in the paper, respectively. One of the nonordinary SUSY representations involves the laddering relations of the two models with respect to the parameters m and n, respectively. Also, the other two of them induce laddering relations with respect to the parameters n and m simultaneously and inversely as well as simultaneously and agreeably.
A TOY MODEL OF CLOSED STRING TACHYON EFFECTIVE ACTION
Authors: KLUSOŇ J.
Published: May 2005

In this paper we propose the toy model of the closed string tachyon effective action that has marginal tachyon profile as its exact solution in case of constant or linear dilaton background. Then we will apply this model for description of two-dimensional bosonic string theory. We will find that the background configuration with the spatial dependent linear dilaton, flat space–time metric and marginal tachyon profile is the exact solution of our model even if we take into account backreaction of tachyon on dilaton and on metric.
AN INTEGRABLE MODEL WITH SOLITON SOLUTIONS WHICH HAVE APPLICATIONS TO TWO-DIMENSIONAL GRAVITY
Authors: BRACKEN PAUL
Published: May 2005

The equations of motion for a theory described by a Chern–Simons type of action in two dimensions are obtained and investigated. The equation for the classical, continuous Heisenberg model is used as a form of gauge constraint to obtain a result which provides a completely integrable dynamics and which partially fixes the gauge degrees of freedom. Under a particular form of the spin connection, an integrable equation which can be analytically extended to a form of the nonlinear Schrödinger equation is obtained. Some explicit solutions are presented, and in particular a soliton solution is shown to lead to an integrable two-dimensional model of gravity.
SYMMETRIES OF AXION–DILATON STRING COSMOLOGY
Authors: MAHARANA JNANADEVA
Published: May 2005

The axion–dilaton string effective action is expressed in Einstein frame metric in a manifestly S-duality invariant form. It is shown that the moduli can be redefined to describe surface of a (2+1)-dimensional pseudosphere. The classical cosmological solutions of axion–dilaton are revisited. The Wheeler–DeWitt equation for the system is exactly solved and complete set of eigenfunctions are presented. The wave function factorizes and the one depending on the moduli is obtained by appealing to the underlying S-duality symmetry. Axion and dilaton parametrize [Formula: see text], the S-duality group, and the Hamiltonian is expressed as a sum of the Ricci scalar and the Casimir of SU (1, 1). Therefore, the complete set of wave functions, depending on the moduli, is obtained from group theory technique. The evidence for the existence of a W-infinity algebra in axion–dilaton cosmology is presented and the origin of the algebra is primarily due to high degree of degeneracies in the wave functions. It is qualitatively argued that axion–dilaton quantum cosmology exhibits chaotic behavior in the semiclassical limit.
ECCENTRIC INFLATION AND WMAP
Authors: BUNIY ROMAN V.
Published: May 2005

For uniform arrangements of magnetic fields, strings, or domain walls (together with the cosmological constant and non-relativistic matter), exact solutions to the Einstein equations are shown to lead to a universe with ellipsoidal expansion. We argue the results can be used to explain some features in the WMAP data. The magnetic field case is the easiest to motivate and has the highest possibility of yielding reliable constraints on observational cosmology.
DILATON SIGNATURES IN THE ELECTROMAGNETIC SPECTRA OF STARS
Authors: CASADIO ROBERTO , FABI SERGIO , HARMS BENJAMIN
Published: May 2005

We study the propagation of classical electromagnetic waves on the simplest four-dimensional spherically symmetric metric with a dilaton background field. Solutions to the relevant equations are obtained perturbatively in a parameter which measures the strength of the dilaton field (hence parameterizes the departure from Schwarzschild geometry). The loss of energy from outgoing modes is estimated as a back-scattering process against the dilaton background, which would affect the luminosity of stars with a dilaton field. The radiation emitted by a freely falling point-like source on such a background is also studied by numerical methods.
DIRECT DETERMINATIONS OF THE REDSHIFT BEHAVIOR OF THE PRESSURE, ENERGY DENSITY, AND EQUATION OF STATE OF THE DARK ENERGY AND THE ACCELERATION OF THE UNIVERSE
Authors: DALY RUTH A. , DJORGOVSKI S. G.
Published: May 2005

One of the goals of current cosmological studies is the determination of the expansion and acceleration rates of the universe as functions of redshift, and the determination of the properties of the dark energy that can explain these observations. Here the expansion and acceleration rates are determined directly from the data, without the need for the specification of a theory of gravity, and without adopting an a priori parameterization of the form or redshift evolution of the dark energy. We use the latest set of distances to SN standard candles from Riess et al. (2004), supplemented by data on radio galaxy standard ruler sizes, as described by Daly & Djorgovski (2003, 2004). We find that the universe transitions from acceleration to deceleration at a redshift of zT≈0.4, with the present value of q0=-0.35±0.15. The standard "concordance model" with Ω0=0.3 and Λ=0.7 provides a reasonably good fit to the dimensionless expansion rate as a function of redshift, though it fits the dimensionless acceleration rate as a function of redshift less well. The expansion and acceleration rates are then combined with a theory of gravity to determine the pressure, energy density, and equation of state of the dark energy as functions of redshift. Adopting General Relativity as the correct theory of gravity, the redshift trends for the pressure, energy density, and equation of state of the dark energy out to z~1 are determined, and are found to be generally consistent with the concordance model; they have zero redshift values of p0=-0.6±0.15, f0=0.62±0.05, and w0=-0.9±0.1.
COSMOLOGY WITH CLUSTERS OF GALAXIES
Authors: DONAHUE M.
Published: May 2005

Cluster observations provide unique and useful constraints on cosmological parameters. The contents of clusters and the rate of their formation are very sensitive to the mean matter density (ΩM and the normalization and shape of the spectrum of initial density perturbations near the size scale of ~8h-1 Mpc . Future and on-going cluster studies constrain ΩΛ (acceleration) and the equation of state of the "dark energy," particularly in conjunction with either constraints from the cosmic microwave background or Type Ia supernovae of white dwarfs.
VARIABLE SPEED OF LIGHT COSMOLOGY AND BIMETRIC GRAVITY: AN ALTERNATIVE TO STANDARD INFLATION
Authors: MOFFAT J. W.
Published: May 2005

A scalar-tensor bimetric gravity model of early universe cosmology is reviewed. The metric frame with a variable speed of light (VSL) and a constant speed of gravitational waves is used to describe a Friedmann-Robertson-Walker universe. The Friedmann equations are solved for a radiation dominated equation of state and the power spectrum is predicted to be scale invariant with a scalar mode spectral index ns=0.97. The scalar modes are born in a ground state superhorizon and the fluctuation modes are causally connected by the VSL mechanism. The cosmological constant is equated to zero and there is no significant dependence on the scalar field potential energy. A possible way of distinguishing the bimetric gravity model from standard inflationary models is discussed.
TESTING THE LEPTOGENESIS MECHANISM OF THE SEESAW MODEL
Authors: JENKINS ELIZABETH
Published: May 2005

The seesaw theory, the leading theory for particle interactions, provides a viable mechanism for generating the matter-antimatter asymmetry of the universe. Testing the leptogenesis mechanism directly requires measurement of the d=6 operator of the low-energy effective Lagrangian, in addition to the more familiar d=5 operator which generates Majorana masses for the light neutrinos when the electroweak symmetry is spontaneously broken. This important experimental challenge awaits the next generation of particle physicists.
TRACING VERY HIGH ENERGY TAU NEUTRINOS FROM COSMOLOGICAL SOURCES IN ICE
Authors: JONES J. , MOCIOIU I. , SARCEVIC I. , RENO M. H.
Published: May 2005

Astrophysical sources of ultrahigh energy neutrinos yield tau neutrino fluxes due to neutrino oscillations. We study in detail the contribution of tau neutrinos with energies above 106 GeV relative to the contribution of the other flavors. We consider several different initial neutrino fluxes and include tau neutrino regeneration in transit through the Earth and energy loss of charged leptons. We discuss signals of tau neutrinos in detectors such as IceCube, RICE and ANITA.
A NATURAL FRAMEWORK FOR BI-LARGE NEUTRINO MIXING
Authors: RABY STUART
Published: May 2005

In this talk I describe a natural framework for bi-large neutrino mixing within the context of two models – 1) a simple generalization of the MSSM and 2) an SO (10) model. Our starting point is the Frampton, Glashow, Yanagida [FGY] neutrino mass ansatz which can easily accomodate bi-large neutrino mixing. The main point of FGY, however, is to obtain a theory of neutrino masses with only one possible CP violating angle. They argue that the sign of the baryon asymmetry of the universe (assuming leptogenesis) is then correlated with CP asymmetries possibly observable in accelerator experiments. Unfortunately, there is a fly in the ointment. It was later shown by Raidal and Strumia [RS] that there is a sign ambiguity which frustrates the above correlation. We note that the Raidal-Strumia ambiguity is resolved in our models.
GLUEBALLS AND THE UNIVERSAL ENERGY SPECTRUM OF TIGHT KNOTS AND LINKS
Authors: BUNIY ROMAN V. , KEPHART THOMAS W.
Published: May 2005

Systems of tightly knotted, linked, or braided flux tubes will have a universal mass-energy spectrum if the flux is quantized. We focus on a model of glueballs as knotted QCD flux tubes.
GAUGE/STRING-GRAVITY DUALITY AND FROISSART BOUND
Authors: KANG KYUNGSIK
Published: May 2005

The gauge/string-gravity duality correspondence opened renewed hope and possibility to address some of the fundamental and non-perturbative QCD problems of in particle physics, such as hadron spectrum and Regge behavior of the scattering amplitude at high energies. One of the most fundamental and long-standing problems is the high energy behavior of the total cross-sections. According to a series of exhaustive tests by the COMPETE group, (1) total cross sections have a universal Heisenberg behavior in energy corresponding to the maximal energy behavior allowed by the Froissart bound, i.e., A+B ln 2(s/s0) with B~0.32 mb and s0~34.41 GeV2 for all reactions, and (2). The factorization relation among σpp,even, σγp and σγγ is well satisfied by experiments. I discuss the recent interesting application of the gauge/string-gravity duality of AdS/CFT correspondence with a deformed background metric so as to break the conformal symmetry that lead to the Heisenberg behavior of rising total cross sections, and present some preliminary results on the high energy QCD from Planckian scattering in AdS and black-hole production.
ON EXTENDED ELECTROWEAK SYMMETRIES
Authors: KONG OTTO C. W.
Published: May 2005

We discuss extensions of the Standard Model through extending the electroweak gauge symmetry. An extended electroweak symmetry requires a list of extra fermionic and scalar states. The former is necessary to maintain cancellation of gauge anomalies, and largely fixed by the symmetry embedding itself. The latter is usually considered quite arbitrary, so long as a vacuum structure admitting the symmetry breaking is allowed. Anomaly cancellation may be used to link the three families of quarks and leptons together, given a perspective on flavor physics. It is illustrated lately that the kind of models may also have the so-called little Higgs mechanism incorporated. This more or less fixes the scalar sector and take care of the hierarchy problem, making such models of extended electroweak symmetries quite appealing candidates as TeV scale effective field theories.
SOFT BREAKING IN SUSY, STRING AND INTERSECTING D BRANE MODELS
Authors: NATH PRAN
Published: May 2005

A brief review of recent developments on soft breaking in SUSY, string and intersecting D brane models is given. The constraints on soft breaking parameters from WMAP data are discussed. A discussion of the constraints of modular invariance on soft breaking within heterotic string models is given. It is shown that the radiative electroweak symmetry breaking leads to a more stringent constraint on soft parameters here than in SUGRA models. Finally, a brief review of recent developments on soft breaking in the framework of intersecting D brane models is given. The issue of gauge coupling unification within intersecting D brane models is briefly discussed.
SPACETIME FOAM, HOLOGRAPHIC PRINCIPLE, AND BLACK HOLE QUANTUM COMPUTERS
Authors: NG Y. JACK , VAN DAM H.
Published: May 2005

Spacetime foam, also known as quantum foam, has its origin in quantum fluctuations of spacetime. Arguably it is the source of the holographic principle, which severely limits how densely information can be packed in space. Its physics is also intimately linked to that of black holes and computation. In particular, the same underlying physics is shown to govern the computational power of black hole quantum computers.
RENORMALIZATION WITHOUT INFINITIES
Authors: 'T HOOFT GERARD
Published: May 2005

Most renormalizable quantum field theories can be rephrased in terms of Feynman diagrams that only contain dressed irreducible 2-, 3-, and 4-point vertices. These irreducible vertices in turn can be solved from equations that also only contain dressed irreducible vertices. The diagrams and equations that one ends up with do not contain any ultraviolet divergences. The original bare Lagrangian of the theory only enters in terms of freely adjustable integration constants. It is explained how the procedure proposed here is related to the renormalization group equations. The procedure requires the identification of unambiguous "paths" in a Feynman diagrams, and it is shown how to define such paths in most of the quantum field theories that are in use today. We do not claim to have a more convenient calculational scheme here, but rather a scheme that allows for a better conceptual understanding of ultraviolet infinities.
GEOMETRIC PROXIMITY GRAPHS FOR IMPROVING NEAREST NEIGHBOR METHODS IN INSTANCE-BASED LEARNING AND DATA MINING
Authors: TOUSSAINT GODFRIED
Published: May 2005

In the typical nonparametric approach to classification in instance-based learning and data mining, random data (the training set of patterns) are collected and used to design a decision rule (classifier). One of the most well known such rules is the k-nearest-neighbor decision rule (also known as lazy learning) in which an unknown pattern is classified into the majority class among its k nearest neighbors in the training set. Several questions related to this rule have received considerable attention over the years. Such questions include the following. How can the storage of the training set be reduced without degrading the performance of the decision rule? How should the reduced training set be selected to represent the different classes? How large should k be? How should the value of k be chosen? Should all k neighbors be equally weighted when used to decide the class of an unknown pattern? If not, how should the weights be chosen? Should all the features (attributes) we weighted equally and if not how should the feature weights be chosen? What distance metric should be used? How can the rule be made robust to overlapping classes or noise present in the training data? How can the rule be made invariant to scaling of the measurements? How can the nearest neighbors of a new point be computed efficiently? What is the smallest neural network that can implement nearest neighbor decision rules? Geometric proximity graphs such as Voronoi diagrams and their many relatives provide elegant solutions to these problems, as well as other related data mining problems such as outlier detection. After a non-exhaustive review of some of the classical canonical approaches to these problems, the methods that use proximity graphs are discussed, some new observations are made, and open problems are listed.
RED-BLUE SEPARABILITY PROBLEMS IN 3D
Authors: HURTADO FERRAN , SEARA CARLOS , SETHIA SAURABH
Published: May 2005

In this paper we study the problems of separability of two disjoint point sets in 3D by multiple criteria extending some notions on separability of two disjoint point sets in the plane.
EUCLIDEAN VORONOI DIAGRAM FOR CIRCLES IN A CIRCLE
Authors: KIM DONGUK , KIM DEOK-SOO , SUGIHARA KOKICHI
Published: May 2005

Presented in this paper is an algorithm to compute a Euclidean Voronoi diagram for circles contained in a large circle. The radii of circles are not necessarily equal and no circle inside the large circle wholly contains another circle. The proposed algorithm uses the ordinary point Voronoi diagram for the centers of inner circles as a seed. Then, we apply a series of edge-flip operations to the seed topology to obtain the correct topology for the desired one. Lastly, the equations of edges are represented in a rational quadratic Bézier curve form.
A NOTE ON FIXED RINGS
Authors: MOUANIS HAKIMA
Published: May 2005

Let R be a ring and G a group of automorphisms of R. In this paper we investigate the transfer of the Von Neumman regularity from the total quotient ring of R to the total quotient ring of its fixed ring. We prove also that, for a locally finite group, Min(RG) inherits the compactness from Min(R), where Min(R) denotes the set of all minimal prime ideals of R. Finally, We explore some conditions under which we can transfer the PF-property (respectively, pseudo PF-property) from a ring to its fixed subring.
INDEPENDENT COMPONENT ANALYSIS FOR CLASSIFYING MULTISPECTRAL IMAGES WITH DIMENSIONALITY LIMITATION
Authors: DU QIAN , KOPRIVA IVICA , SZU HAROLD
Published: May 2005

Airborne and spaceborne remote sensors can acquire invaluable information about earth surface, which have many important applications. The acquired information usually is represented as two-dimensional grids, i.e. images. One of techniques to processing such images is Independent Component Analysis (ICA), which is particularly useful for classifying objects with unknown spectral signatures in an unknown image scene, i.e. unsupervised classification. Since the weight matrix in ICA is a square matrix for the purpose of mathematical tractability, the number of objects that can be classified is equal to the data dimensionality, i.e. the number of spectral bands. When the number of sensors (or spectral channels) is very small (e.g. a 3-band CIR photograph and 6-band Landsat image with the thermal band being removed), it is impossible to classify all the different objects present in an image scene using the original data. In order to solve this problem, we present a data dimensionality expansion technique to generate artificial bands. Its basic idea is to use nonlinear functions to capture and highlight the similarity/dissimilarity between original spectral measurements, which can provide more data with additional information for detecting and classifying more objects. The results from such a nonlinear band generation approach are compared with a linear band generation method using cubic spline interpolation of pixel spectral signatures. The experiments demonstrate that nonlinear band generation approach can significantly improve unsupervised classification accuracy, while linear band generation method cannot since no new information can be provided. It is also demonstrated that ICA is more powerful than other frequently used unsupervised classification algorithms such as ISODATA.
RESEARCH ON BULK MICRO-MACHINED MICROELECTRODE BIOSENSOR
Authors: LIU JINGWEI , BIAN CHAO , XIA SHANHONG , HAN JINGHONG , CHEN SHAOFENG
Published: May 2005

A new silicon-based amperometric microelectrode biosensor produced using bulk micromachining technology is presented here. Bulk micromachining, platinization and polymerization of pyrrole enhance sensitive coefficient, thus helping to miniaturize its dimensions and reduce unit cost. To our knowledge, platinization and polymerization of pyrrole is first used consecutively for microelectrode surface modification. Successful experimental results have been achieved for glucose detection. Compared to conventional amperometric biosensors and amperometric microelectrode biosensors made with surface micromachining technology, it has several advantages, such as smaller sensing surface area (1 mm × 1 mm ), lower detection limit (1×10-4 M ), larger sensitive coefficient (39.640 nA mM -1 mm -2), broader linear range (1 × 10-4-1 × 10-2 M ), better replicability (3.2% RSD for five respective detections) and stability (enzyme efficiency remains well above 95% after being stored for a month), easier to be made into arrays and to be integrated with processing circuitry, etc.
STUDY ON THE SOLID-STATE ELECTROCHEMICAL SENSOR TECHNIQUES FOR THE DETECTION OF CO2 AND O2 GASES
Authors: FENG LIANG-DONG , ZHOU ZHONG-BAI
Published: May 2005

A new type of solid-state electrochemical sensor was studied in this paper. By mixing proper content of polyacrylonitrile (PAN)-Polyvinylpyrrolidone (PVP)-Dimethylsulfoxide (DMSO)-Tetraethylammonium perchlorate (TEAP), an elastic and porous polymeric solid electrolyte was developed. According to the microelectrode theory and modulated pulse potential technique, an electrochemical sensor that can realize the synchronous and fast detection of CO 2 and O 2 at room temperature was designed. Experimental data showed that this polymer electrolyte exhibited ionic conductivity of the order of 10-4 S/cm at room temperature, and also showed that the sensor had many advantages such as small volume, convenient usage and certain extent stability.
A TWO-HOP ENERGY-EFFICIENT MESH PROTOCOL FOR WIRELESS SENSOR NETWORKS
Authors: LIU PETER XIAOPING , LIU YIMIN
Published: May 2005

We develop a novel energy-efficient routing protocol called the THEEM (Two-Hop Energy-Efficient Mesh) protocol for wireless sensor networks. In the THEEM protocol, a comprehensive and integrated treatment is employed to achieve energy efficiency. In specific, a two-hop in-mesh transmission scheme and a centralized mesh (cluster) formulation method are employed, along with other design innovations, such as the concepts of mesh layer/column, the power-aware assignment of mesh heads and a low-energy media access protocol. Simulation results show that the THEEM protocol is able to reduce energy consumption quite significantly compared to currently existing protocols. Equal energy dissipation among all sensor nodes in a network is also achieved. In addition, the protocol maximizes network data throughput.
ON THE BV QUANTIZATION OF GAUGE GRAVITATION THEORY
Authors: BASHKIROV D. , SARDANASHVILY G.
Published: May 2005

Quantization of gravitation theory as gauge theory of general covariant transformations in the framework of Batalin–Vilkoviski (BV) formalism is considered. Its gauge-fixed Lagrangian is constructed.
SPIN STRUCTURES ON MANIFOLDS AND ASHTEKAR VARIABLES
Authors: FATIBENE L. , FRANCAVIGLIA M.
Published: May 2005

We review the classical notion of spin structure on a (pseudo)-Rienannian manifold and appropriately extend it to be applied to manifolds without any a priori fixed metric structure. The relation with soldering forms is discussed in detail and so-called Ashtekar variables for four-dimensional Euclidean GR are introduced as a leading application.
HIDDEN CONSEQUENCE OF ACTIVE LOCAL LORENTZ INVARIANCE
Authors: RODRIGUES W. A. , ROCHA R. DA , VAZ J.
Published: May 2005

In this paper we investigate a hidden consequence of the hypothesis that Lagrangians and field equations must be invariant under active local Lorentz transformations. We show that this hypothesis implies in an equivalence between spacetime structures with several curvature and torsion possibilities.
Do rat cardiac myocytes release ATP on contraction?
Authors: Gödecke Stefanie , Stumpe Thomas , Schiller Hilmar , Schnittler Hans-J. , Schrader Jürgen
Published: May 2005

ATP is released by numerous cell types in response to mechanical strain. It then acts as a paracrine or autocrine signaling molecule, inducing a variety of biological responses. In this work, we addressed the question whether mechanical force acting on the membranes of contracting cardiomyocytes during periodic longitudinal shortening can stimulate the release of ATP. Electrically stimulated isolated adult rat cardiomyocytes as well as spontaneously contracting mouse cardiomyocytes derived from embryonic stem (ES) cells were assayed for ATP release with the use of luciferase and a sensitive charge-coupled device camera. Sensitivity of soluble luciferase in the supernatant of cardiomyocytes was 100 nM ATP, which is ∼10-fold below the EC50 values for most purinergic receptors expressed in the heart (1.5–20 μM). Light intensities were not different between resting or contracting adult rat cardiomyocytes. Similar results were obtained with ES-cell-derived contracting mouse cardiomyocytes. ATP release was measurable only from obviously damaged or permeabilized cells. To increase selectivity and sensitivity of ATP detection we have targeted a recombinant luciferase to the sarcolemmal membrane using a wheat germ agglutinin-IgG linker. Contraction of labeled adult rat cardiomyocytes was not associated with measurable bioluminescence. However, when human umbilical vein endothelial cells were targeted with membrane-bound luciferase, shear stress-induced ATP release could be clearly detected, demonstrating the sensitivity of the detection method. In the present study, we did not detect ATP release from contracting cardiomyocytes on the single cell level, despite adequate sensitivity of the detection system. Thus deformation of the contracting cardiomyocyte is not a key stimulus for the release of cellular ATP.
Polyamine depletion induces nucleophosmin modulating stability and transcriptional activity of p53 in intestinal epithelial cells
Authors: Zou Tongtong , Rao Jaladanki N. , Liu Lan , Marasa Bernard S. , Keledjian Kaspar M. , Zhang Ai-Hong , Xiao Lan , Bass Barbara L. , Wang Jian-Ying
Published: May 2005

Our previous studies have shown that polyamines are required for normal intestinal mucosal growth and that decreased levels of polyamines inhibit intestinal epithelial cell (IEC) proliferation by stabilizing p53 and other growth-inhibiting proteins. Nucleophosmin (NPM) is a multifunctional protein that recently has been shown to regulate p53 activity. In the present study, we sought to determine whether polyamine depletion increases NPM modulating the stability and transcriptional activity of p53 in a normal IEC-6 intestinal epithelial cell line. Depletion of cellular polyamines by α-difluoromethylornithine, the specific inhibitor of polyamine biosynthesis, stimulated expression of the NPM gene and induced nuclear translocation of NPM protein. Polyamine depletion stimulated NPM expression primarily by increasing NPM gene transcription and its mRNA stability, and it induced NPM nuclear translocation through activation of phosphorylation of mitogen-activated protein kinase kinase. Increased NPM interacted with p53 and formed a NPM/p53 complex in polyamine-deficient cells. Inhibition of NPM expression by small interfering RNA targeting NPM (siNPM) not only destabilized p53 as indicated by a decrease in its protein half-life but also prevented the increased p53-dependent transactivation as shown by suppression of the p21 promoter activity. Decreased expression of NPM by siNPM also promoted cell growth in polyamine-deficient cells. These results indicate that 1) polyamine depletion increases expression of the NPM gene and enhances NPM nuclear translocation and 2) increased NPM interacts with and stabilizes p53, leading to inhibition of IEC-6 cell proliferation.
Modeling error and stability of endothelial cytoskeletal membrane parameters based on modeling transendothelial impedance as resistor and capacitor in series
Authors: Bodmer James E. , English Anthony , Brady Megan , Blackwell Ken , Haxhinasto Kari , Fotedar Sunaina , Borgman Kurt , Bai Er-Wei , Moy Alan B.
Published: May 2005

Transendothelial impedance across an endothelial monolayer grown on a microelectrode has previously been modeled as a repeating pattern of disks in which the electrical circuit consists of a resistor and capacitor in series. Although this numerical model breaks down barrier function into measurements of cell-cell adhesion, cell-matrix adhesion, and membrane capacitance, such solution parameters can be inaccurate without understanding model stability and error. In this study, we have evaluated modeling stability and error by using a χ2 evaluation and Levenberg-Marquardt nonlinear least-squares (LM-NLS) method of the real and/or imaginary data in which the experimental measurement is compared with the calculated measurement derived by the model. Modeling stability and error were dependent on current frequency and the type of experimental data modeled. Solution parameters of cell-matrix adhesion were most susceptible to modeling instability. Furthermore, the LM-NLS method displayed frequency-dependent instability of the solution parameters, regardless of whether the real or imaginary data were analyzed. However, the LM-NLS method identified stable and reproducible solution parameters between all types of experimental data when a defined frequency spectrum of the entire data set was selected on the basis of a criterion of minimizing error. The frequency bandwidth that produced stable solution parameters varied greatly among different data types. Thus a numerical model based on characterizing transendothelial impedance as a resistor and capacitor in series and as a repeating pattern of disks is not sufficient to characterize the entire frequency spectrum of experimental transendothelial impedance.
Degradation of oxidative stress-induced denatured albumin in rat liver endothelial cells
Authors: Bito Ryuji , Hino Sayaka , Baba Atsushi , Tanaka Miharu , Watabe Haruka , Kawabata Hiroaki
Published: May 2005

We previously identified conformationally denatured albumin (D2 and D3 albumin) in rats with endotoxicosis (Bito R, Shikano T, and Kawabata H. Biochim Biophys Acta 1646: 100–111, 2003). In the present study, we attempted first to confirm whether the denatured albumins generally increase in conditions of oxidative stress and second to characterize the degradative process of the denatured albumin using primary cultured rat liver endothelial cells. We used five models of oxidative stress, including endotoxicosis, ischemic heart disease, diabetes, acute inflammation, and aging, and found that serum concentrations of D3 albumin correlate with the serum levels of thiobarbituric acid-reactive substance ( R = 0.87), whereas the concentrations of D2 albumin are 0.52. Ligand blot analysis showed that the D3 albumin binds to gp18 and gp30, which are known endothelial scavenger receptors for chemically denatured albumin. Primary cultured rat liver endothelial cells degraded the FITC-D3 albumin, and the degradation rate decreased to ∼60% of control levels in response to anti-gp18 and anti-gp30 antibodies, respectively. An equimolar mixture of these antibodies produced an additive inhibitory effect on both uptake and degradation, resulting in levels ∼20% those of the control. Furthermore, filipin and digitonin, inhibitors of the caveolae-related endocytic pathway, reduced the FITC-D3 albumin uptake and degradation to <20%. Laser-scanning confocal microscopic observation supported these data regarding the uptake and degradation of D3 albumin. These results indicate that conformationally denatured D3 albumin occurs generally under oxidative stress and is degraded primarily via gp18- and gp30-mediated and caveolae-related endocytosis in liver endothelial cells.
Role for Calcium Signaling and Arachidonic Acid Metabolites in the Activity-Dependent Increase of AHP Amplitude in Leech T Sensory Neurons
Authors: Scuri Rossana , Mozzachiodi Riccardo , Brunelli Marcello
Published: May 2005

Previous studies have revealed a new form of activity-dependent modulation of the afterhyperpolarization (AHP) in tactile (T) neurons of the leech Hirudo medicinalis. The firing of T cells is characterized by an AHP, which is mainly due to the activity of the Na+/K+ATPase. Low-frequency repetitive stimulation of T neurons leads to a robust increment of the AHP amplitude, which is correlated with a synaptic depression between T neuron and follower cells. In the present study, we explored the molecular cascades underlying the AHP increase. We tested the hypothesis that this activity-dependent phenomenon was triggered by calcium influx during neural activity by applying blockers of voltage-dependent Ca2+channels. We report that AHP increase requires calcium influx that, in turn, induces release of calcium from intracellular stores so sustaining the enhancement of AHP. An elevation of the intracellular calcium can activate the cytosolic isoforms of the phosholipase A2 (PLA2). Therefore we analyzed the role of PLA2 in the increase of the AHP, and we provide evidence that not only PLA2 but also the recruitment of arachidonic acid metabolites generated by the 5-lipoxygenase pathway are necessary for the induction of AHP increase. These data indicate that a sophisticated cascade of intracellular signals links the repetitive discharge of T neurons to the activation of molecular pathways, which finally may alter the activity of critical enzymes such as the Na+/K+ATPase, that sustains the generation of the AHP and its increase during repetitive stimulation. These results also suggest the potential importance of the poorly studied 5-lipoxygenase pathway in forms of neuronal plasticity.
Sulfhydryl Oxidation Reduces Hippocampal Susceptibility to Hypoxia-Induced Spreading Depression by Activating BK Channels
Authors: Hepp Sebastian , Gerich Florian J. , Müller Michael
Published: May 2005

The cytosolic redox status modulates ion channels and receptors by oxidizing/reducing their sulfhydryl (SH) groups. We therefore analyzed to what degree SH modulation affects hippocampal susceptibility to hypoxia. In rat hippocampal slices, severe hypoxia caused a massive depolarization of CA1 neurons and a negative shift of the extracellular DC potential, the characteristic sign of hypoxia-induced spreading depression (HSD). Oxidizing SH groups by 5,5′-dithiobis 2-nitrobenzoic acid (DTNB, 2 mM) postponed HSD by 30%, whereas their reduction by 1,4-dithio-dl-threitol (DTT, 2 mM) or alkylation by N-ethylmaleimide (500 μM) hastened HSD onset. The DTNB-induced postponement of HSD was not affected by tolbutamide (200 μM), dl-2-amino-5-phosphonovaleric acid (150 μM), or 6-cyano-7-nitroquinoxaline-2,3-dione (25 μM). It was abolished, however, by Ni2+(2 mM), withdrawal of extracellular Ca2+, charybdotoxin (25 nM), and iberiotoxin (50 nM). In CA1 neurons DTNB induced a moderate hyperpolarization, blocked spontaneous spike discharges and postponed the massive hypoxic depolarization. DTT induced burst firing, depolarized glial cells, and hastened the onset of the massive hypoxic depolarization. Schaffer-collateral/CA1 synapses were blocked by DTT but not by DTNB; axonal conduction remained intact. Mitochondria did not markedly respond to DTNB or DTT. While the targets of DTT are less clear, the postponement of HSD by DTNB indicates that sulfhydryl oxidation increases the tolerance of hippocampal tissue slices against hypoxia. We identified as the underlying mechanism the activation of BK channels in a Ca2+-sensitive manner. Accordingly, ionic disregulation and the loss of membrane potential occur later or might even be prevented during short-term insults. Therefore well-directed oxidation of SH groups could mediate neuroprotection.