bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of intense wrestling exercise on leucocytes and adhesion molecules in adolescent boys
Authors: Nemet D , Mills P J , Cooper D M
Published: March 2004

Background:In adults, exercise is a powerful and natural stimulator of immune cells and adhesion molecules. Far less is known about exercise responses during childhood and adolescence and whether or not exercise in “real life” activities of healthy adolescents influences immune responses.

Objective:To determine if strenuous exercise leads to significant changes in leucocyte number and adhesion molecule expression in adolescent boys.

Methods:Eleven healthy, high school boys, aged 14–18.5 years, performed a single, typical, 1.5 hour wrestling practice session. Blood was sampled before and after the session. Flow cytometry was used to evaluate changes in immune responses.

Results:The exercise led to significant (p<0.05) and robust increases in granulocytes, monocytes, and all lymphocyte subpopulations. The most significant changes were observed for natural killer cells (p<0.0005). The number of T cytotoxic and T helper cells expressing CD62L increased significantly (p<0.002 and p<0.0005 respectively), as did the number of T cytotoxic and T helper cells not expressing CD62L (p<0.003 and p<0.009 respectively). The density of CD62L on lymphocytes decreased significantly with exercise (p<0.0005), whereas CD11a (p<0.01) and CD54 (p<0.01) increased.

Conclusions:The data show that an intense wrestling bout in adolescent boys leads to profound stimulation of the immune system. The role of these common changes in overall immune status and the development of the immune and haemopoietic systems has yet to be determined.
Effectiveness of rugby headgear in preventing soft tissue injuries to the head: a case-control and video cohort study: Table 1
Authors: Jones S J , Lyons R A , Evans R , Newcombe R G , Nash P , McCabe M , Palmer S R
Published: March 2004

Objective:To determine if headgear use by rugby players was associated with a reduced risk of head or facial laceration, abrasion, or fracture.

Methods:An emergency department based case-control study in South Wales, UK, with cases being rugby players treated for superficial head and facial injuries and controls being their matched opponents during the game. A review of videos of the 41 games in the 1999 Rugby World Cup was also carried out to compare with the case-control study. Odds ratios (OR) and 95% confidence intervals (95% CI) were used to measure association between exposure (headgear wearing) and outcome (head and facial injuries).

Results:In the case-control study, 164 pairs were analysed, with headgear worn by 12.8% of cases and 21.3% of controls. Headgear use was associated with substantial but non-significant reductions in superficial head (OR  =  0.43, 95% CI 0.13 to 1.19) and facial (OR  =  0.57, 95% CI 0.21 to 1.46) injuries. The video study followed 547 players over 41 games, during which there were 47 bleeding injuries to the head. Headgear use significantly reduced the risk of bleeding head injury in forwards (OR  =  0.14, 95% CI 0.01 to 0.99, p  =  0.02), but not in backs. There was also a higher risk of facial injury among forwards, but this was not significant.

Conclusions:The combined results suggest that headgear can prevent certain types of superficial head injuries in players at all levels of the game, but the evidence is strongest for superficial head injury in elite forwards. A randomised controlled trial would be the best way to study this further.
Injuries in youth amateur soccer and rugby players—comparison of incidence and characteristics
Authors: Junge A , Cheung K , Edwards T , Dvorak J
Published: March 2004

Objectives:In reviewing the literature on sports injuries, few studies could be found in which exposure related incidences of injury in different types of sport were compared. These studies indicated that ice hockey, handball, basketball, soccer, and rugby are popular team sports with a relatively high risk of injury. The aim of the study was to compare the characteristics and incidence of injuries in male youth amateur soccer and rugby players.

Methods:This prospective cohort study comprised an initial baseline examination to ascertain the characteristics of the players and their level of performance, and a one season observation period during which a physician visited the team weekly and documented all occurring injuries. Twelve soccer and 10 rugby school teams with male amateur players aged 14–18 years were selected for the study. 145 soccer and 123 rugby players could be followed up over one season.

Results:Comparison of the incidence of soccer and rugby injuries indicated that rugby union football was associated with a significantly higher rate of injury than soccer. The differences were pronounced for contact injuries, injuries of the head, neck, shoulder, and upper extremity, as well as for concussion, fractures, dislocations, and strains. Rugby players incurred 1.5 times more overuse and training injuries in relation to exposure time, and 2.7 times more match injuries than soccer players. Three rugby players but no soccer players had to stop their participation in sport because of severe injury.

Conclusion:The incidence of injury in New Zealand school teams playing soccer or rugby union is high, probably in part because of the low ratio of hours spent in training relative to hours spent playing matches. The development and implementation of preventive interventions to reduce the rate and severity of injury is recommended.
Combining isometric knee extension exercises with hip adduction or abduction does not increase quadriceps EMG activity
Authors: Hertel J , Earl J E , Tsang K K W , Miller S J
Published: March 2004

Objective:To determine if the combined isometric contractions of knee extension/hip adduction and knee extension/hip abduction will elicit a different quadriceps and gluteus medius electromyographic (EMG) pattern as compared to isometric contraction of a uniplanar knee extension exercise.

Methods:Eight healthy young adult volunteers without history of knee or quadriceps injury participated. Surface EMG data were collected from the vastus medialis oblique (VMO), vastus lateralis (VL), and gluteus medius (Gmed) muscles of the dominant leg of each subject during three single leg, weight bearing, isometric exercises (uniplanar knee extension, knee extension/hip adduction, knee extension/hip abduction). All exercises were performed at a position of 60° knee flexion. Three trials lasting 5 s each were performed for each of the three exercises. EMG data from each muscle were integrated and the maximum root mean square activity over a 0.5 s window for each trial was averaged. Analyses of variance were performed with exercise (straight extension, extension/adduction, extension/abduction) as the independent variable and VMO, VL, and Gmed activity and VMO:VL ratio as dependent variables.

Results:A significant main effect for exercise was found for the VMO (p = 0.006) and VL (p = 0.02), but not the Gmed (p = 0.25) or the VMO:VL ratio (p = 0.13). For the VMO and VL, the uniplanar knee extension task produced significantly more EMG activity than the extension/adduction or extension/abduction tasks.

Conclusions:Uniplanar knee extension exercises may be more appropriate than combining isometric knee extension exercises with hip adduction or abduction when eliciting maximal VMO and VL contractions.
Negative neurofunctional effects of frequency, depth and environment in recreational scuba diving: the Geneva “memory dive” study
Authors: Slosman D O , de Ribaupierre S , Chicherio C , Ludwig C , Montandon M-L , Allaoua M , Genton L , Pichard C , Grousset A , Mayer E , Annoni J-M , de Ribaupierre A
Published: March 2004

Objectives:To explore relationships between scuba diving activity, brain, and behaviour, and more specifically between global cerebral blood flow (CBF) or cognitive performance and total, annual, or last 6 months’ frequencies, for standard dives or dives performed below 40 m, in cold water or warm sea geographical environments.

Methods:A prospective cohort study was used to examine divers from diving clubs around Lac Léman and Geneva University Hospital. The subjects were 215 healthy recreational divers (diving with self-contained underwater breathing apparatus). Main outcome measures were: measurement of global CBF by133Xe SPECT (single photon emission computed tomography); psychometric and neuropsychological tests to assess perceptual-motor abilities, spatial discrimination, attentional resources, executive functioning, and memory; evaluation of scuba diving activity by questionnaire focusing on number and maximum depth of dives and geographical site of the diving activity (cold watervwarm water); and body composition analyses (BMI).

Results:(1) A negative influence of depth of dives on CBF and its combined effect with BMI and age was found. (2) A specific diving environment (more than 80% of dives in lakes) had a negative effect on CBF. (3) Depth and number of dives had a negative influence on cognitive performance (speed, flexibility and inhibition processing in attentional tasks). (4) A negative effect of a specific diving environment on cognitive performance (flexibility and inhibition components) was found.

Conclusions:Scuba diving may have long-term negative neurofunctional effects when performed in extreme conditions, namely cold water, with more than 100 dives per year, and maximal depth below 40 m.
Chronic groin pain in an amateur soccer player
Authors: Cetin C , Sekir U , Yildiz Y , Aydin T , Ors F , Kalyon T A
Published: March 2004

Chronic groin pain is common in soccer players because of the biomechanics of kicking causing recurrent stress to the abdominal muscles, groin flexors, and adductor muscles. Myositis ossificans in adductor muscles is a rare cause of chronic groin pain in soccer players. Only two cases have been reported and the iliopsoas muscle was involved in both. This case report emphasises the importance of direct radiography for diagnosis in chronic groin pain and is a reminder that the development of myositis ossificans in the adductor muscles may be a cause.
Failure of operative treatment in a fast bowler with bilateral spondylolysis: Figure 1
Authors: Ranawat V S , Heywood-Waddington M B
Published: March 2004

Modern day fast bowling places immense strain on the spine. Stress fractures of the lumbar region are common. If a period of conservative treatment fails to return a fast bowler to professional sport, surgery is considered. Good results have been reported using a direct screw repair of the spondylolytic defect. A case is presented of a failed surgical intervention with an alternative technique.
Effects of exercise on the physical condition of college rugby players during summer training camp
Authors: Mashiko T , Umeda T , Nakaji S , Sugawara K
Published: March 2004

Objectives:To determine the effects of exercise training on physical condition in 25 college rugby players during a summer training camp, and to compare these variables by the different players’ positions.

Methods:Changes in body composition parameters and blood biochemistry were examined before and after a summer training camp.

Results:Body weight and percentage body fat did not change significantly during the camp. There were significant decreases in levels of serum total cholesterol, triglycerides, phosphate, uric acid, and immunoglobulin G and M. In contrast, there were significant increases in levels of serum potassium, markers of renal, hepatic, and muscular damage (BUN, GOT, GPT, LDH, CK), and complement C4. Comparison of the changes in biochemical parameters between rugby players playing in different positions showed a significant increase in serum albumin level in the forwards, and significant decreases in serum triglyceride and sodium levels in the backs. The magnitude of change in serum LDH during the camp was significantly greater (p<0.05) for the forwards than for the backs.

Conclusions:These data suggest that, in rugby players attending a 20 day camp, exercise training resulted in muscular damage, loss of electrolytes due to sweating, and changes in immune function. Backs exhibited a higher rate of fat metabolism and loss of electrolytes than forwards, possibly because they did more running during the camp. In contrast, forwards experienced more physical contact, performed more physically strenuous exercise, and exhibited higher levels of muscular damage and tissue protein degradation.
Field and laboratory testing in young elite soccer players
Authors: Chamari K , Hachana Y , Ahmed Y B , Galy O , Sghaïer F , Chatard J-C , Hue O , Wisløff U
Published: March 2004

Aim:To determine if there are correlations between the physical fitness of young soccer players assessed by field and laboratory testing.

Methods:Thirty four male soccer players took part in the study (mean (SD) age 17.5 (1.1) years, height 177.8 (6.7) cm, weight 70.5 (6.4) kg). Maximal oxygen uptake (Vo2max) during treadmill running and vertical jump height on a force platform were measured in the laboratory. Field tests consisted of a soccer specific endurance test (Bangsbo test) and 30 m sprint with 10 m lap times.

Results:The Bangsbo test correlated with the lowest velocity associated with Vo2max(vVo2max;R2 =  0.55, p<0.001), but not with Vo2max. Sprint times at 30 m and 20 m were related to peak extension velocity and peak extension force measured during vertical jumping, but not to vertical jump height per se. The jumping force and velocity could explain 46% of the 30 m sprint performance (R2 =  0.46, p<0.001).

Conclusion:The Bangsbo test and 30 m sprint test correlate withvVo2maxand vertical jump force and velocity respectively. The Bangsbo test does not give a good estimate of Vo2maxin young soccer players.
Anthropometry, physical performance, and ultrasound patellar tendon abnormality in elite junior basketball players: a cross-sectional study
Authors: Cook J L , Kiss Z S , Khan K M , Purdam C R , Webster K E
Published: March 2004

Objective:Patellar tendinopathy has been reported to be associated with many intrinsic risk factors. Few have been fully investigated. This cross-sectional study examined the anthropometric and physical performance results of elite junior basketball players with normal or abnormal patellar tendons to see if any measures were associated with changes in tendon morphology.

Methods:Agility, leg strength, endurance, and flexibility were measured in 71 male and 64 female players. A blinded radiologist ultrasonographically examined their patellar tendons and athletes were grouped as having normal or abnormal tendons. One-way ANOVA was used to test for differences in anthropometric and physical performance data for athletes whose tendons were normal or abnormal (unilateral or bilateral tendinopathy) on ultrasound.

Results:Results show that females with abnormalities in their tendons had a significantly better vertical jump (50.9±6.8 cm) than those with normal tendons (46.1±5.4 cm) (p = 0.02). This was not found in males. In males, the mean sit and reach in those with normal tendons (13.2±6.7 cm) was greater (p<0.03) than in unilateral tendinopathy (10.3±6.2 cm) or in bilateral tendinopathy (7.8±8.3 cm). In females, those with normal tendons (13.3±4.8 cm) and bilateral tendinopathy (15.8±6.2 cm) were distinctly different from those with unilateral tendinopathy (7.9±6.6 cm).

Conclusion:Flexibility and vertical jump ability are associated with patellar tendinopathy and the findings warrant consideration when managing young, jumping athletes.
Reliability and validity of measures taken during the Chester step test to predict aerobic power and to prescribe aerobic exercise
Authors: Buckley J P , Sim J , Eston R G , Hession R , Fox R
Published: March 2004

Objectives:To evaluate the reliability and validity of measures taken during the Chester step test (CST) used to predict VO2max and prescribe subsequent exercise.

Methods:The CST was performed twice on separate days by 7 males and 6 females aged 22.4 (SD 4.6) years. Heart rate (HR), ratings of perceived exertion (RPE), and oxygen uptake (VO2) were measured at each stage of the CST.

Results:RPE, HR, and actual VO2were the same at each stage for both trials but each of these measures was significantly different between CST stages (p<0.0005). Intertrial bias ±95% limits of agreement (95% LoA) of HR reached acceptable limits at CST stage IV (−2±10 beats/min) and for RPE at stages III (0.2±1.4) and IV (0.5±1.9). Age estimated HRmax significantly overestimated actual HRmax of 5 beats/min (p = 0.016) and the 95% LoA showed that this error could range from an underestimation of 17 beats/min to an overestimation of 7 beats/min. Estimated versus actual VO2at each CST stage during both trials showed errors ranging between 11% and 19%. Trial 1 underestimated actual VO2max by 2.8 ml/kg/min (p = 0.006) and trial 2 by 1.6 ml/kg/min (not significant). The intertrial agreement in predicted VO2max was relatively narrow with a bias ±95% LoA of −0.8±3.7 ml/kg/min. The RPE and %HRmax (actual) correlation improved with a second trial. At all CST stages in trial 2 RPE:%HRmax coefficients were significant with the highest correlations at CST stages III (r = 0.78) and IV (r = 0.84).

Conclusion:CST VO2max prediction validity is questioned but the CST is reliable on a test-retest basis. VO2max prediction error is due more to VO2estimation error at each CST stage compared with error in age estimated HRmax. The HR/RPE relation at >50% VO2max reliably represents the recommended intensity for developing cardiorespiratory fitness, but only when a practice trial of the CST is first performed.
NONUNITAL SPECTRAL TRIPLES ASSOCIATED TO DEGENERATE METRICS
Authors: RENNIE A.
Published: March 2004

We show that one can define (p,∞)-summable spectral triples using degenerate metrics on smooth manifolds. Furthermore, these triples satisfy Connes–Moscovici's discrete and finite dimension spectrum hypothesis, allowing one to use the Local Index Theorem [1] to compute the pairing with K-theory. We demonstrate this with a concrete example.
N=2 SUPER-YANG–MILLS ACTION AND BRST COHOMOLOGY
Authors: ÜLKER K.
Published: March 2004

The extended BRST cohomology of N=2 super-Yang–Mills theory is discussed in the framework of Algebraic Renormalization. In particular, N=2 supersymmetric descent equations are derived from the cohomological analysis of linearized Slavnov–Taylor operator ℬ. It is then shown that both off- and on-shell N=2 super-Yang–Mills actions are related to a lower-dimensional gauge-invariant field polynomial Tr ϕ2 by solving these descent equations. Moreover, it is found that these off- and on-shell solutions differ only by a ℬ-exact term, which can be interpreted as a consequence of the fact that the cohomology of both cases are the same.
GAUGINO CONDENSATION IN HETEROTIC FIVE-BRANE BACKGROUND
Authors: KITAZAWA NORIAKI
Published: March 2004

The gaugino propagator is calculated by explicitly considering the propagation of a heterotic string between two different points in spacetime using the nontrivial worldsheet conformal field theory for the five-brane background. We find that there are no propagations of gaugino which is in the spinor representation of the nontrivial four-dimensional space of the five-brane background. This result is consistent with the arguments on the fermion zero-modes of the five-brane background in the low-energy heterotic supergravity theory. Furthermore, assuming the continuous limit to the flat spacetime background at the place far away from the five-brane, we suggest an effective propagator which is effective only at the place far away from the five-brane in the flat spacetime limit. From the effective propagator we evaluate a possible gaugino pair condensation. The result is consistent with the suggested scenario of the gaugino condensation in the five-brane background in the low-energy heterotic supergravity theory.
GENERALIZED SCALAR–TENSOR THEORY FOR BIANCHI SPACETIME MODELS
Authors: CHAKRABORTY NARAYAN CHANDRA , CHAKRABORTY SUBENOY
Published: March 2004

This work deals with Bianchi cosmological models where geometry is coupled to a scalar field with variable coupling constant (depending on the scalar field). Considering a bulk viscous fluid, the possibility of exponential or power law form of solutions have been examined. The modified Einstein equations have been solved with some reasonable assumptions among the physical parameters and solutions have been discussed.
MEASURING LANGUAGE
Authors: SADDY DOUGLAS , URIAGEREKA JUAN
Published: March 2004

The study of language, its processing and its bearing on human cortical processes are all extensive domains of investigation in their own right. In this overview tutorial we limit ourselves to a sample of core illustrative issues. Our central aim is to demonstrate how complexity within the language faculty arises from two a priori distinct sources: the computational complexity inherent in the grammar of the language system itself and the procedural complexity resulting from marshalling processing resources in order to produce or interpret utterances that correspond to the grammar. Distinguishing between these two sources of complexity is a current goal in investigations of the human language faculty. The combination of quantitative approaches with newer qualitative approaches to the analysis of electro-cortical behavior associated with carefully controlled language paradigms represents a new approach to clarifying this central issue.
LANGUAGE PROCESSING BY DYNAMICAL SYSTEMS
Authors: BEIM GRABEN PETER , JURISH BRYAN , SADDY DOUGLAS , FRISCH STEFAN
Published: March 2004

We describe a part of the stimulus sentences of a German language processing ERP experiment using a context-free grammar and represent different processing preferences by its unambiguous partitions. The processing is modeled by deterministic pushdown automata. Using a theorem proven by Moore, we map these automata onto discrete time dynamical systems acting at the unit square, where the processing preferences are represented by a control parameter. The actual states of the automata are rectangles lying in the unit square that can be interpreted as cylinder sets in the context of symbolic dynamics theory. We show that applying a wrong processing preference to a certain input string leads to an unwanted invariant set in the parsers dynamics. Then, syntactic reanalysis and repair can be modeled by a switching of the control parameter — in analogy to phase transitions observed in brain dynamics. We argue that ERP components are indicators of these bifurcations and propose an ERP-like measure of the parsing model.
AUTAPSE TURNS NEURON INTO OSCILLATOR
Authors: HERRMANN CHRISTOPH S. , KLAUS ANDREAS
Published: March 2004

Recently, neurobiologists have discovered axons on neurons which synapse on the same neuron's dendrites — so-called autapses. It is not yet clear what functional significance autapses offer for neural behavior. This is an ideal case for using a physical simulation to investigate how an autapse alters the firing of a neuron. We simulated a neural basket cell via the Hodgkin–Huxley equations and implemented an autapse which feeds back onto the soma of the neuron. The behavior of the cell was compared with and without autaptic feedback. Our artificial autapse neuron (AAN) displays oscillatory behavior which is not observed for the same model neuron without autapse. The neuron oscillates between two functional states: one where it fires at high frequency and another where firing is suppressed. This behavior is called "spike bursting" and represents a common pattern recorded from cerebral neurons.
INTERNAL AND EXTERNAL NEURAL SYNCHRONIZATION DURING CONSCIOUS PERCEPTION
Authors: SRINIVASAN RAMESH
Published: March 2004

Binocular rivalry is a useful experimental paradigm to investigate aspects of neocortical dynamics related to conscious perception. Frequency-tagged EEG responses to a sine-flickered visual stimulus were contrasted between episodes of perceptual dominance, i.e. conscious perception of that stimulus and perceptual nondominance, i.e. conscious perception of a rival stimulus presented at a different frequency to the other eye. The amplitude and phase distribution of the stimulus-evoked steady-state responses depended on the stimulus modulation frequency, consistent with the presence of global resonance phenomena. At the apparent global resonance frequency, conscious perception of the stimulus modulated the steady-state response over the entire array of electrodes. These effects were significant at electrodes far from the primary visual cortex, including temporal, central, and frontal electrodes. The phase structure of the steady-state response was also investigated using coherence measures. Coherence between electrodes mostly increased during conscious perception of the stimulus. Analysis of partial coherence, removing stimulus-locked responses, indicated that synchronization of each signal to the stimulus flicker at each electrode and synchronization between signals that vary with respect to the stimulus flicker at each electrode both contribute to observed increases in coherence during conscious perception. These distinct modes of synchronization may reflect two different physiological mechanisms by which sensory signals are integrated across the cerebral cortex during conscious experience.
EVOKED OSCILLATIONS AND EARLY COMPONENTS OF EVENT-RELATED POTENTIALS: AN ANALYSIS
Authors: KLIMESCH WOLFGANG , SCHABUS MANUEL , DOPPELMAYR MICHAEL , GRUBER WALTER , SAUSENG PAUL
Published: March 2004

In the present work, we provide new arguments and data indicating that early ERP components are generated at least in part by evoked theta and alpha oscillations. We proceed from the general hypothesis, originally proposed by Erol Basar that ERP's are generated by a superposition of evoked oscillations with different frequencies. Based on findings about event-related desynchronization/synchronization (ERD/ERS), we analyze the following specific hypotheses. If evoked theta and alpha oscillations contribute to the generation of ERP components and if their functional role, type of reactivity and frequency specificity are similar to those of event-related oscillations (measured by ERD/ERS), we expect (i) to see the same functional relationship between frequency and cognitive processes, (ii) the same type of "reactivity" and a (iii) dependency of latency measures of evoked components on IAF. By reviewing respective data, we demonstrate that similar to research about event-related oscillations, evoked alpha reflects attention, whereas evoked theta reflects working memory processes. Furthermore, it was found that individual alpha frequency (IAF) has a significant influence on P1 latency in particular. For a better understanding of these findings, we outline a new theoretical framework. We assume that the P1–N1 complex is generated by an interplay between the synchronous activation of three neuronal network systems, a working memory, attentional, and semantic memory system, each operating with a different frequency, the first in the theta (about 6 Hz), the second in the lower alpha (about 8 Hz) and the third in the upper alpha (about 12 Hz) frequency range. The implications of this theoretical framework are discussed by reviewing research using phase sensitive measures to analyze "local" and "large scale" integration processes between different neural networks.
EXTENDED RECURRENCE PLOT ANALYSIS AND ITS APPLICATION TO ERP DATA
Authors: MARWAN NORBERT , MEINKE ANJA
Published: March 2004

We present new measures of complexity and their application to event-related potential data. The new measures are based on structures of recurrence plots and makes the identification of chaos–chaos transitions possible. The application of these measures to data from single-trials of the Oddball experiment can identify laminar states therein. This offers a new way of analyzing event-related activity on a single-trial basis.
TESTING FOR PHASE SYNCHRONIZATION
Authors: ALLEFELD CARSTEN , KURTHS JÜRGEN
Published: March 2004

We present different tests for phase synchronization which improve the procedures currently used in the literature. This is accomplished by using a two-sample test setup and by utilizing insights and methods from directional statistics and bootstrap theory. The tests differ in the generality of the situation in which they can be applied as well as in their complexity, including computational cost. A modification of the resampling technique of the bootstrap is introduced, making it possible to fully utilize data from time series.
UNCOVERING SHORT-TIME CORRELATIONS BETWEEN MULTICHANNEL RECORDINGS OF BRAIN ACTIVITY: A PHASE-SPACE APPROACH
Authors: GALÁN R. FDEZ , RITZ R. , HERZ A. V. M. , SZYSZKA P.
Published: March 2004

Short-time correlations in multivariate time series are notoriously difficult to detect. Extending the classical concept of correlation, we present a method to tackle this problem with little computational cost. In essence, the method uncovers multidimensional phase-locking and is especially useful for revealing changes of the dynamical coupling between different brain areas. The approach also permits us to estimate the shortest time-window in which the coupling occurs. Furthermore, the coupling can be quantified by a measure that defines a metric space. Therefore it may be used to identify task-dependent coupling hierarchies between two brain areas. We illustrate the analysis technique by studying the dynamical coupling between two brain regions involved in olfactory processing in the honeybee. We show that the neural activity in both areas is coupled with each other and that the coupling increases significantly during odor processing.
EXISTENCE OF A "HOT" ATOM MECHANISM FOR THE DISSOCIATION OF O2 ON Pt (111) AND THE PHASE DIAGRAM OF CATALYTIC OXIDATION OF CO
Authors: KHAN K. M. , IQBAL K.
Published: March 2004

The catalytic oxidation of CO has already been studied over a square surface through Monte-Carlo simulation via a model based on the Langmuir–Hinshelwood mechanism, in which dissociated adsorption of the O 2 molecule is considered on a pair of vacancies in the nearest neighborhood. The results of this study are well known. Here, we have studied this reaction on the basis of an experimentally observed hot atom mechanism on the Pt (111) surface. According to this mechanism the probability of adsorption of the O 2 molecule on a pair of vacancies in the nearest neighborhood is negligibly small. It is shown that if the two oxygen atoms are adsorbed at two lattice constants apart, then the model yields a steady reactive window where the continuous transition disappears. The production of CO 2 starts the moment CO partial pressure departs from zero, which is seen in the experimental situation.
MAGNETIC PROPERTIES OF ICOSAHEDRAL COPPER-COATED COBALT CLUSTERS
Authors: WANG BAOLIN , CHEN XIAOSHUANG , CHEN GUIBIN , WANG GUANGHOU , ZHAO JIJUN
Published: March 2004

The structural and magnetic properties of Cu -coated Co clusters are investigated with empirical genetic algorithm simulation and a spin-polarized spd tight-binding model Hamiltonian. In some specific stoichiometric compositions, icosahedral Co n (n=1, 2, 4, 7, 13, 19, 55) clusters perfectly coated with A Cu monolayer or dual layer are obtained. The outer Cu layers lead to significant modification of the magnetic moment of the Co core, depending on the structure and thickness of the Cu layers. The interaction between Cu and Co atoms induces a nonzero magnetic moment for Cu atoms.
STUDY OF THE SURFACE STATES AND ACTIVITY OF APt/TiO2PHOTOCATALYST
Authors: MAO LIQUN , LI QINGLIN , DANG HONGXIN , ZHANG ZHIJUN
Published: March 2004

This paper deals with the correlation of surface states and photoactivity of a Pt/TiO2catalyst prepared by means of photoreduction of [Formula: see text] on anatase nano- TiO2powders. Conductivity measurements of pressed powders and XPS were applied in analysis of the surface states energy levels and chemical states of Pt at the nano- TiO2surface, respectively. The results revealed a new surface state with the energy level of 0.35 eV, lower than the conduction band edge of TiO2. According to the XPS analysis, the new surface state can be attributed to the Pt0clusters deposited on the surface of TiO2particles. The photoactivity of the as-prepared Pt/TiO2catalyst was characterized by photodecoloration of brilliant red X-3B in aqueous solution. The experimental results indicated that the photoactivity of the Pt/TiO2catalyst is much higher than that of TiO2. The surface Pt0clusters possibly function as trapping centers of generated electrons, resulting in the promotion of photocatalytic activity.
TRANSMISSION OF PHONON MODES IN QUASI-ONE-DIMENSIONAL WAVEGUIDES VIA DOUBLE L-SHAPED JOINT NANOSTRUCTURES
Authors: BELHADI M. , KHATER A. , MASCHKE K.
Published: March 2004

The influence of a special class of atomic nanostructures embedded on a waveguide is analyzed for the scattering and transmission of elastic waves in quasi-one-dimensional multicanal waveguides. The quasi-one-dimensional waveguide is constructed of double chains of atoms, and the nanostructures consist of geometrical configurations, where the double chains are arranged to form several types of double L-shaped joints. Numerical results are presented for the three types of nanostructures, using the matching method. The theoretical approach allows us to calculate the reflection and the transmission probabilities as well as the average phonon conductance of the system along the waveguide. The results show that the transmission probabilities and the average conductance depend strongly on the type of geometrical joint nanostructure. The pronounced fluctuations in the transmission and conductance spectra as a function of the frequency can be understood as Fano resonances that result from the coherent coupling between the propagating modes and the localized vibrational modes induced by the nanostructures.
PERFORMANCE BOUNDARIES OF OPTIMAL WEIGHTED MEDIAN FILTERS
Authors: LUKAC RASTISLAV
Published: March 2004

This paper focuses on image filtering using weighted median (WM) filters, a nonlinear filter class taking advantages of the robust order-statistic theory and capability to adapt a filter behavior for a variety of statistics related to the desired signals and the noise distributions. The main contribution of the paper is the analysis of the four WM optimization schemes, namely genetic WM optimization, non-adaptive WM optimization algorithm and adaptive WM filtering utilizing the linear and the sigmoidal approximation of the sign function. The analysis is done by extensive simulations, in which several features such as noise reduction, edge preservation, error estimation and dependence of error criteria on the degree of the impulse noise corruption, are examined.
FAST IMPLEMENTATION OF MORPHOLOGICAL OPERATIONS USING BINARY IMAGE BLOCK DECOMPOSITION
Authors: GATOS BASILIOS , PERANTONIS STAVROS J. , PAPAMARKOS NIKOS , ANDREADIS IOANNIS
Published: March 2004

Morphological transformations are commonly used to perform a variety of image processing tasks. However, morphological operations are time-consuming procedures since they involve ordering and min/max computation of numbers resulting from image interaction with structuring elements. This paper presents a new method that can be used to speed up basic morphological operations for binary images. To achieve this, the binary images are first decomposed in a set of non-overlapping rectangular blocks of foreground pixels that have predefined maximum dimensions. Then off-line dilation and erosion of all rectangular blocks are arbitrary obtained and stored into suitable look-up array tables. By using the look up tables, the results of the morphological operations to the rectangular blocks are directly obtained. Thus, first all image blocks are replaced by their look-up array tables. Then the morphological operations are applied only to the limited number of the remaining pixels. Experimental results reveal that starting from a block represented binary image morphological operations can be executed with different types of structuring elements in significantly less CPU time. Using the block representation, we are able to perform dilation 16 times faster than non-fast implementations and 10 times faster than an alternative fast implementation based on contour processing. Significant acceleration is also recorded when using this approach for repeated application of dilation (for 10 iterations, dilation using the block representation is over 20 times faster than non-fast implementations and over four times faster than using the fast contour based approach).
HANDWRITTEN BANK CHECK RECOGNITION OF COURTESY AMOUNTS
Authors: PALACIOS RAFAEL , GUPTA AMAR , WANG PATRICK S.
Published: March 2004

In spite of rapid evolution of electronic techniques, a number of large-scale applications continue to rely on the use of paper as the dominant medium. This is especially true for processing of bank checks. This paper examines the issue of reading the numerical amount field. In the case of checks, the segmentation of unconstrained strings into individual digits is a challenging task because of connected and overlapping digits, broken digits, and digits that are physically connected to pieces of strokes from neighboring digits. The proposed architecture involves four stages: segmentation of the string into individual digits, normalization, recognition of each character using a neural network classifier, and syntactic verification. Overall, this paper highlights the importance of employing a hybrid architecture that incorporates multiple approaches to provide high recognition rates.
CLOSED FREE-FORM SURFACE GEOMETRICAL MODELING A NEW APPROACH WITH GLOBAL AND LOCAL CHARACTERIZATION
Authors: MARI JEAN-LUC , SEQUEIRA JEAN
Published: March 2004

In this paper, we present a new approach to geometrical modeling which allows the user to easily characterize and control the shape defined to a closed surface. We will focus on dealing with the shape's topological, morphological and geometrical properties separately. To do this, we have based our work on the following observations concerning surfaces defined by control-points, and implicit surfaces with skeleton. They both provide complementary approaches to the surface's deformation, and both have specific advantages and limits. We thus attempted to conceive a model which integrates the local and geometrical characterization induced by the control points, as well as the representation of the morphology given by the skeleton. Knowing that the lattice of control points is close to the surface and that the skeleton is centered in the related shape, we thought of a 3-layer model. The transition layer separates the local geometrical considerations from those linked to the global morphology. We apply our model to shape design in order to modify an object in an interactive and ergonomic way, as well as to reconstruction which allows better shape understanding. To do so, we present the algorithms related to these processes.
SECONDARY TRANSFORM DECOUPLING OF SHIFTED NONSTATIONARY SIGNAL MODULATION COMPONENTS: APPLICATION TO PHOTOPLETHYSMOGRAPHY
Authors: ADDISON PAUL S. , WATSON JAMES N.
Published: March 2004

We present a method for the detection of pertinent signal features masked by other features with similar spectral content but which perturb (but not necessarily periodically) other constituent parts of the signal. This modulation may be a modulation in frequency and/or amplitude of a locus of chosen selected points on a transform surface. A secondary transform is then performed on this derived signal. We apply the method, which we have termed secondary wavelet feature decoupling (SWFD), to the specific problem of decomposition and analysis of signals used in pulse oximetry where perturbations of the ridges in wavelet space associated with the pulse band may be used to detect respiration features. The method has wide application to problematic signals in many other disciplines.
WAVELET-BASED MULTIRESOLUTION HISTOGRAM FOR FAST IMAGE RETRIEVAL
Authors: JAIN PAWAN , MERCHANT S. N.
Published: March 2004

Most of the content-based image retrieval systems require a distance computation of feature vectors for each candidate image in the image database. This exhaustive search is highly time-consuming and inefficient. This limits the usefulness of such system. Thus there is a growing need for a fast image retrieval system. Multiresolution data-structure algorithm provides a good solution to the above problem. In this paper we propose a wavelet-based multiresolution data-structure algorithm. Wavelet-based multiresolution data-structure further reduce the number of computation by around 50%. In the proposed approach we reuse the information obtained at lower resolution levels to calculate the distance at a higher resolution level. Apart from this, the proposed structure saves memory overheads by about 50% over multiresolution data-structure algorithm. The proposed algorithm can be easily combined with other algorithms for performance enhancement.4 In this paper we use the proposed technique to match luminance histogram for image retrieval. Fuzzy histograms enhances performance by considering the similarity between neighboring bins. We have extended the proposed approach to fuzzy histograms for better performance.
APPLYING WAVELET RECURSIVE TRANSLATION-INVARIANT TO WINDOW LOW-PASS FILTERED IMAGES
Authors: ISMAIL I. A. , NABIL TAMER
Published: March 2004

This work gives an algorithm that makes up for the many iterations and the loss of some main features encountered in the usual methods of wavelet transform filtering. The wavelet transform technique is merged with the window low-pass method. The results are acceptable.
A domain mimic increases ΔF508 CFTR trafficking and restores cAMP-stimulated anion secretion in cystic fibrosis epithelia
Authors: Clarke Lane L. , Gawenis Lara R. , Hwang Tzyh-Chang , Walker Nancy M. , Gruis Darren B. , Price Elmer M.
Published: March 2004

The major disease-causing mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) is deletion of phenylalanine 508 (ΔF508), which adversely affects processing and plasma membrane targeting of CFTR. Under conditions predicted to stabilize protein folding, ΔF508 CFTR is capable of trafficking to the plasma membrane and retains cAMP-regulated anion channel activity. Overexpression is one factor that increases CFTR trafficking; therefore, we hypothesized that expression of a domain mimic of the first nucleotide-binding fold (NBF1) of CFTR, i.e., the site of F508, may be sufficient to overwhelm the quality control process or otherwise stabilize ΔF508 CFTR and thereby restore cAMP-stimulated anion secretion. In epithelial cells expressing recombinant ΔF508 human (h)CFTR, expression of wild-type NBF1 increased the amount of both core-glycosylated and mature protein to a greater extent than expression of ΔF508 NBF1. Expression of wild-type NBF1 in the ΔF508 hCFTR cells increased whole cell Cl− current density to ∼50% of that in cells expressing wild-type hCFTR. Expression of NBF1 in polarized epithelial monolayers from a ΔF508/ΔF508 cystic fibrosis mouse (MGEF) restored cAMP-stimulated transepithelial anion secretion but not in monolayers from a CFTR-null mouse (MGEN). Restoration of anion secretion was sustained in NBF1-expressing MGEF for >30 passages, whereas MGEN corrected with hCFTR progressively lost anion secretion capability. We conclude that expression of a NBF1 domain mimic may be useful for correction of the ΔF508 CFTR protein trafficking defect in cystic fibrosis epithelia.
G1 cell cycle progression and the expression of G1 cyclins are regulated by PI3K/AKT/mTOR/p70S6K1 signaling in human ovarian cancer cells
Authors: Gao Ning , Flynn Daniel C. , Zhang Zhuo , Zhong Xiao-Song , Walker Valerie , Liu Ke Jian , Shi Xianglin , Jiang Bing-Hua
Published: March 2004

Ovarian cancer is one of the most common cancers among women. Recent studies demonstrated that the gene encoding the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K) is frequently amplified in ovarian cancer cells. PI3K is involved in multiple cellular functions, including proliferation, differentiation, antiapoptosis, tumorigenesis, and angiogenesis. In this study, we demonstrate that the inhibition of PI3K activity by LY-294002 inhibited ovarian cancer cell proliferation and induced G1 cell cycle arrest. This effect was accompanied by the decreased expression of G1-associated proteins, including cyclin D1, cyclin-dependent kinase (CDK) 4, CDC25A, and retinoblastoma phosphorylation at Ser780, Ser795, and Ser807/811. Expression of CDK6 and β-actin was not affected by LY-294002. Expression of the cyclin kinase inhibitor p16INK4a was induced by the PI3K inhibitor, whereas steady-state levels of p21CIP1/WAF1 were decreased in the same experiment. The inhibition of PI3K activity also inhibited the phosphorylation of AKT and p70S6K1, but not extracellular regulated kinase 1/2. The G1 cell cycle arrest induced by LY-294002 was restored by the expression of active forms of AKT and p70S6K1 in the cells. Our study shows that PI3K transmits a mitogenic signal through AKT and mammalian target of rapamycin (mTOR) to p70S6K1. The mTOR inhibitor rapamycin had similar inhibitory effects on G1 cell cycle progression and on the expression of cyclin D1, CDK4, CDC25A, and retinoblastoma phosphorylation. These results indicate that PI3K mediates G1 progression and cyclin expression through activation of an AKT/mTOR/p70S6K1 signaling pathway in the ovarian cancer cells.
Role of renald-amino-acid oxidase in pharmacokinetics ofd-leucine
Authors: Hasegawa Hiroshi , Matsukawa Takehisa , Shinohara Yoshihiko , Konno Ryuichi , Hashimoto Takao
Published: March 2004

d-Amino acids are now recognized to be widely present in mammals. Renal d-amino-acid oxidase (DAO) is associated with conversion of d-amino acids to the corresponding α-keto acids, but its contribution in vivo is poorly understood because the α-keto acids and/or l-amino acids formed are indistinguishable from endogenous compounds. First, we examined whether DAO is indispensable for conversion of d-amino acids to their α-keto acids by using the stable isotope tracer technique. After a bolus intravenous administration of d-[2H7]leucine to mutant mice lacking DAO activity (ddY/DAO−) and normal mice (ddY/DAO+), elimination of d-[2H7]leucine and formation of α-[2H7]ketoisocaproic acid ([2H7]KIC) and l-[2H7]leucine in plasma were determined. The ddY/DAO−mice, in contrast to ddY/DAO+mice, failed to convert d-[2H7]leucine to [2H7]KIC and l-[2H7]leucine. This result clearly revealed that DAO was indispensable for the process of chiral inversion of d-leucine. We further investigated the effect of renal mass reduction by partial nephrectomy on elimination of d-[2H7]leucine and formation of [2H7]KIC and l-[2H7]leucine. Renal mass reduction slowed down the elimination of d-[2H7]leucine. The fraction of conversion of d-[2H7]leucine to [2H7]KIC in sham-operated rats was 0.77, whereas that in five-sixths-nephrectomized rats was 0.25. The elimination behavior of d-[2H7]leucine observed in rats suggested that kidney was the principal organ responsible for converting d-leucine to KIC.