bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in the element composition of globoids from Cucurbita maxima and Cucurbita andreana cotyledons during early seedling growth
Authors: Beecroft Penny , Lott John N. A.
Published: January 2008

Energy dispersive X-ray analysis was used to study the element composition of globoids from the cotyledons of Cucurbita maxima and Cucurbita andreana seeds and seedlings at various stages of growth. The influence of light and mineral nutrient conditions on changes in globoid composition was also investigated. The element composition of globoids changed markedly during early seedling growth. In both species, regardless of light and mineral nutrient conditions, K decreased markedly, Mg, Ca, Fe, Mn, and Zn generally increased, and P remained relatively constant. There were differences in globoid composition changes between the two species that could be attributed, at least in part, to differences in the Ca content of the mature, dry embryos. In C. andreana, which had a higher initial Ca content, there was a large increase in the Ca content of the globoids during seedling growth and no significant increase in Mn. In C. maxima globoids, there was only a slight increase in Ca, but there was a much larger increase in Fe, Zn, and Mn than occurred in C. andreana. Light conditions alone did not have a significant influence on the changes in globoid composition. Light, in combination with mineral nutrients, resulted in a more rapid degradation of globoids in the later stages of growth. Mineral nutrient conditions affected mostly elements that were initially present in large amounts. There were very large, globoid-like particles present in some later stage samples of both species, from each of the different growth conditions. These particles had element compositions that were consistent with their being composed of phytate. Keywords: Cucurbita, energy dispersive X-ray analysis, globoids, mineral nutrient reserves, large particles.
Organogénie florale des genres Culcasia et Cercestis (Araceae)
Authors: Barabé Denis , Bertrand Charles
Published: January 2008

The floral development of Culcasia saxatilis, Culcasia tenuifolia, and Cercestis stigmaticus has been analyzed. These two genera possess unisexual flowers without perianth. In these species, the cylindrical inflorescence carry male flowers in the upper part and female flowers in the lower part. In C. tenuifolia, the separation between the female zone and the male zone is very sharp. There is no intermediate zone. In C. saxatilis and C. stigmaticus, we may observe rudimentary bisexual flowers between the two zones. In this intermediate zone, flowers located near the male zone possess male appendages more developped than those located near the female zone. On the other hand, the flowers located near the female zone possess female appendages more developped than those located near the male zone. The results suggest the existence of a morphogenetic gradient in the inflorescence of some species of Araceae. Keywords: morphogenesis, gradient, flower, development, inflorescence.
Cloning of the ATP sulphurylase gene ofSchizosaccharomyces pombeby functional complementation
Authors: Simonics Tibor , Maráz Anna
Published: January 2008

The ATP sulphurylase gene of Schizosaccharomyces pombe has been cloned by complementation of cysteine auxotrophy of a selenate-resistant mutant, which supposedly had a defect in ATP sulphurylase. A sulphate nonutilizing (cysteine auxotrophic) and selenate-resistant mutant of S. pombe was transformed with a wild-type S. pombe genomic library and sulphate-utilizing clones were isolated. The open reading frame encoding the ATP sulphurylase enzyme was found to be responsible for the restoration of sulphate assimilation. Transformants became as sensitive for selenate as the wild-type strain and produced a comparable amount of ATP sulphurylase as the prototrophic strains. The cloned ATP sulphurylase gene (sua1) proved to be an efficient selection marker in an ARS vector, when different isogenic or nonisogenic S. pombe selenate-resistant mutants were used as cloning hosts. Complementation of sua1–mutations by sua1-bearing multicopy vectors functions as a useful dual positive and negative selection marker. The cloned sua1 gene also complemented the met3 (ATP sulphurylase deficient) mutation in Saccharomyces cerevisiae .
Chromosomalgfplabelling ofPseudomonas aeruginosausing a mini-Tn7transposon: application for studies of bacteria–host interactions
Authors: Barnes Rebecca J. , Leung Kam Tin , Schraft Heidi , Ulanova Marina
Published: January 2008

Analysis of bacterial interactions with host cells using multiple techniques is essential for studies on microbial pathogenesis and for the development of new antimicrobial therapies. Pseudomonas aeruginosa is an important opportunistic pathogen that can cause severe, often life-threatening pulmonary infections in individuals with impaired host defense mechanisms. Using a mini-Tn7 transposon delivery system, we have chromosomally labelled the strain P. aeruginosa PAK with a green fluorescent protein gene (gfp) and tested PAKgfp as a research tool for studies of bacteria–host interactions. We were able to reliably and rapidly measure the interactions of PAKgfp with A549 human lung epithelial cells by using flow cytometry, a fluorometric microplate reader-based assay, and fluorescence microscopy. With these analytical tools, we have demonstrated the adhesion of PAKgfp to the extracellular matrix protein fibronectin and the involvement of fibronectin in PAKgfp–A549 cell interactions. PAKgfp can be successfully used to explore the effects of various pharmacological compounds on P. aeruginosa – host cell interactions in both in vitro and in vivo systems, with potentially important medical applications.
CHARACTERIZATION OF OFFSET PRINTING INK TAGGED WITH RARE-EARTH TAGGANTS BY X-RAY EMISSION TECHNIQUES
Authors: JOSEPH D. , MAIND S. D. , SAXENA A. , CHOUDHURY R. K.
Published: January 2008

Proton Induced X-ray Emission (PIXE) and Energy Dispersive X-ray Fluorescence (EDXRF) techniques have been used for elemental characterization of offset printing ink tagged with rare-earth taggants. The offset printing ink was tagged with rare-earth ( La , Pr , Nd , Sm , Eu and Gd ) thenoyltrifluoroacetonate chelates at about 1000-ppm level for each element separately. Small aliquots (approximately 20 mg) of tagged inks were coated on paper supports in the form of small circles having diameter 10–15 mm each and then analyzed. In the case of PIXE, a proton beam of energy 4 MeV and in the case of EDXRF a radioisotope source of241Am (100 mCi ) was used to excite the samples. The PIXE analysis showed well-resolved rare-earth L X-rays and EDXRF analysis showed the K X-rays of rare earths. Satisfactory results to identify and quantify the taggants were achieved.
GAMMA- RAY SPECTROSCOPIC AND PIXE ANALYSIS OF BEACH ROCK SAMPLES OF SOUTH EAST COAST OF TAMILNADU, INDIA
Authors: RAVISANKAR R. , RAJALAKSHMI A. , ESWARAN P. , MEENAKASHISUNDRAM V. , GAJENDIRAN V. , MANIKANDAN E. , MAGUDAPATHY P. , PANIGRAHI B. K. , NAIR K. G. M.
Published: January 2008

Beach rock samples collected from South East Coast of Tamilnadu was analyzed by natural radioactive measurements to detect the presence of radioactive elements. PIXE technique was used to obtain elemental composition of beach rocks. The PIXE analysis was carried out using 1.7 MV tandem accelerators with the energy of 2 MeV protons at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamilnadu, India. The geochemical behavior of the elements in the region is discussed. The occurrence of the radioactive and non-radioactive elements is discussed for their geological significance. The results were used to assess environmental toxicity of heavy metals and radiation hazard in the study area.
ON THE INCOMPRESSIBLE LIMIT FOR THE NAVIER–STOKES–FOURIER SYSTEM IN DOMAINS WITH WAVY BOTTOMS
Authors: FEIREISL EDUARD , NOVOTNÝ ANTONÍN , PETZELTOVÁ HANA
Published: January 2008

In this paper, the Oberbeck–Boussinesq approximation is identified as a singular limit of the full Navier–Stokes–Fourier system provided the Mach and Froude numbers tend to zero. The result holds for any ill-prepared initial data and without any restrictions imposed on the length of the time interval. In particular, it is shown that the velocity converges almost everywhere, the oscillations of the sound waves being effectively damped by the presence of a "wavy bottom" of the physical domain.
PERFORMANCE EVALUATION OF REACTIVE AND PROACTIVE PROTOCOLS FOR AD-HOC SENSOR NETWORKS USING DIFFERENT RADIO MODELS
Authors: YANG TAO , BAROLLI LEONARD , IKEDA MAKOTO , DURRESI ARJAN , XHAFA FATOS
Published: January 2008

In this paper, we consider the behavior of a wireless ad-hoc sensor network for different radio models. By means of simulations, we analyze the performance of three protocols: AODV, DSR, and DSDV considering two radio models TwoRayGround and Shadowing.

In difference with other works, we generalize the type of radio model by allowing the path loss randomnesses to be present in the service environment of the network. We study the perceived Goodput and Depletion of the ad-hoc sensor network and compare the performance of three protocols for different scenarios. The simulation results confirm the fact that the shadowing phenomena, by destroying the regularity of the network, reduce the mean distance among nodes and at the same time increase the interference level and the latency of packet transmission. In particular, we found a maximum relative difference of 70%. On the other hand, for the proactive DSDV routing protocol the energy consumption rate seems to be independent of the radio model, at least for moderate size of the network (256 nodes). Also, we found that the packet delivery ratio of AODV and DSR routing protocols are more stable than DSDV protocol.
AN EXPERIMENTAL STUDY ON GENETIC ALGORITHMS FOR RESOURCE ALLOCATION ON GRID SYSTEMS
Authors: XHAFA FATOS , BAROLLI LEONARD , DURRESI ARJAN
Published: January 2008

Computational Grid (CG) is an emerging paradigm in which geographically distributed resources are logically unified as a computational unit. A challenging problem in such systems is the allocation of jobs to resources that minimizes both makespan and flowtime parameters. In this paper, we present an experimental study on Genetic Algorithms (GAs) for scheduling independents jobs to Grid resources based on two replacement strategies: Steady-State GA (SSGA) and Struggle GA (SGA). SSGA distinguishes for its accentuated convergence of the population that rapidly reaches good solutions though it is soon stagnated. The SGA is based on struggle replacement and adaptively maintains diverse population, reducing thus convergence rapidity. The experimental results, based on a benchmark simulation model, showed that SGA outperforms SSGA for moderate size instances. On the other hand, the time needed by the SGA to reach makespan values obtained by the SSGA rapidly increases as more jobs and machines are added to the Grid. Thus, for larger size instances, SGA is not able to improve the results of the SSGA. Finally, we also report and analyze flowtime values for the considered benchmark.
THEORETICAL ANALYSIS ON NEURAL OSCILLATOR TOWARD BIOMIMIC ROBOT CONTROL
Authors: ZHANG DINGGUO , ZHU KUANYI
Published: January 2008

Neural oscillator is derived from the central pattern generator (CPG) in the biological nervous system. It can generate motor patterns for the rhythmic movements. Neural oscillator is widely adopted in biomimic robot and humanoid robot for different types of rhythmic movement controls such as swimming and walking. Theoretical analysis about neural oscillator toward biomimic robot control is presented in this paper. The methods adopted here include stability theory, describing function, and piecewise linear analysis. Some important properties of the neural oscillator, such as the determination of frequency, oscillation, and stability, are exploited. Network property of multiple neural oscillators is also studied. The insightful results will strengthen the foundation of the neural oscillator and enhance its efficient application for robotic control purpose.
NIKOLA TESLA AND ROBOTICS
Authors: VUKOBRATOVIC MIOMIR K.
Published: January 2008

The paper analyzes some of Tesla's works and his most remarkable views concerning the problem of formulating theoretical bases of automatic control. As a tribute to Tesla's work on remote control of automated systems, as well to his (at the time) far-seeing visions, special attention is paid to solving the complex problem of control and feedback application. A more detailed discussion of the way and origin of formulating theoretical bases of automatic control is given. Besides, in more detail are presented the related pioneering works of Professor Nicholas Bernstein, great Russian physiologist who formulated the basic rules of the self-regulating movements of man. Bernstein has achievements of highest scientific significance that has been in a direct function of identifying and proving the priority of his pioneering contributions in the domain of feedback, i.e. control and principles of cybernetics.
DYNAMICALLY BALANCED ASCENDING AND DESCENDING GAITS OF A TWO-LEGGED ROBOT
Authors: VUNDAVILLI PANDU RANGA , SAHU SAMBIT KUMAR , PRATIHAR DILIP KUMAR
Published: January 2008

The present paper deals with dynamically balanced ascending and descending gait generations of a 7 DOF biped robot negotiating a staircase. During navigation, the foot of the swing leg is assumed to follow a trajectory, after ensuring its kinematic constraints. Dynamic balance margin of the gaits are calculated by using the concept of zero-moment point (ZMP). In the present work, an approach different from the well-known semi-inverse method has been developed for trunk motion generation, in which it is initially generated based on static balance and then checked for its dynamic balance. The joint torques are determined utilizing the Lagrange–Euler formulation, and the average power consumption at each joint is calculated. Moreover, variations of the dynamic balance margin are studied for both the ascending as well as descending gaits of the biped robot. Average dynamic balance margin and average power consumption in the ascending gait are found to be more than that of the descending gait. The effect of trunk mass on the dynamic balance margin and average power consumption for both the ascending and descending gaits are studied. The dynamic balance margin and average power consumption are found to decrease and increase, respectively with the increase in the trunk mass.
Characterization of the metasomatic agent in mantle xenoliths from Devès, Massif Central (France) using coupled
in situ
trace-element and O, Sr and Nd isotopic compositions
Authors: Touron S. , Renac C. , O'Reilly S. Y. , Cottin J.-Y. , Griffin W. L.
Published: January 2008

Spinel lherzolites and harzburgites from Mont-Briançon and Marais de Limagne in the Devès volcanic district display coarse-grained to porphyroclastic microstructures and the modal content of volatile-bearing phases increases with the degree of deformation. Clinopyroxene and/or spinel are partly or totally reacted to amphibole. The coupled interpretations of trace-element, rare earth element (REE) and O–Sr–Nd data for clinopyroxene and amphibole indicate that the metasomatized mantle beneath Devès is a mixture of depleted and enriched mantle associated with an alkaline, high field strength element poor, and light rare earth element, U- and Th-rich carbonate-rich silicate fluid–melt metasomatic agent. Oxygen isotope and REE data for clinopyroxene–amphibole pairs indicate a (La/Yb)
N
enrichment related to an increasing metasomatic agent/rock ratio.
Expression and function of rat urothelial P2Y receptors
Authors: Chopra Bikramjit , Gever Joel , Barrick Stacey R. , Hanna-Mitchell Ann T. , Beckel Jonathan M. , Ford Anthony P. D. W. , Birder Lori A.
Published: January 2008

The control and regulation of the lower urinary tract are partly mediated by purinergic signaling. This study investigated the distribution and function of P2Y receptors in the rat urinary bladder. Application of P2Y agonists to rat urothelial cells evoked increases in intracellular calcium; the rank order of agonist potency (pEC50 ± SE) was ATP (5.10 ± 0.07) > UTP (4.91 ± 0.14) > UTPγS (4.61 ± 0.16) = ATPγS (4.70 ± 0.05) > 2-methylthio adenosine 5′-diphosphate = 5′-( N-ethylcarboxamido)adenosine = ADP (<3.5). The rank order potency for these agonists indicates that urothelial cells functionally express P2Y2/P2Y4 receptors, with a relative lack of contribution from other P2Y or adenosine receptors. Real-time PCR, Western blotting, and immunocytochemistry confirmed the expression of P2Y2 and to a lesser extent P2Y4 in the urothelium. Immunocytochemical studies revealed expression of P2Y2 staining in all layers of the urothelium, with relative absence of P2Y4. P2Y2 staining was also present in suburothelial nerve bundles and underlying detrusor smooth muscle. Addition of UTP and UTPγS was found to evoke ATP release from cultured rat urothelial cells. These findings indicate that cultured rat urothelial cells functionally express P2Y2/P2Y4 receptors. Activation of these receptors could have a role in autocrine and paracrine signaling throughout the urothelium. This could lead to the release of bioactive mediators such as additional ATP, nitric oxide, and acetylcholine, which can modulate the micturition reflex by acting on suburothelial myofibroblasts and/or pelvic afferent fibers.
Netrin-1 and kidney injury. I. Netrin-1 protects against ischemia-reperfusion injury of the kidney
Authors: Wang Weiwei , Brian Reeves W. , Ramesh Ganesan
Published: January 2008

Endogenous mechanisms exist to limit inflammation. One such molecule is netrin. This study examined the impact of ischemia-reperfusion (I/R) on netrin expression and the role of netrin in preventing renal inflammation and injury. All three isoforms of netrin (1, 3, and 4) are expressed in normal kidney. I/R significantly downregulated netrin-1 and -4 mRNA expression, whereas expression of netrin-3 was moderately upregulated at 24 h of reperfusion. The netrin receptor UNC5B mRNA increased at 3 h and but decreased at later time points. Expression of a second netrin receptor, DCC, was not altered significantly. I/R was associated with dramatic changes in netrin-1 protein abundance and localization. Netrin-1 protein levels increased between 3 and 24 h after reperfusion. Immunolocalization showed an interstitial distribution of netrin-1 in sham-operated kidneys which colocalized with Von Willebrand Factor suggesting the presence of netrin-1 in peritubular capillaries. After I/R, interstitial netrin-1 expression decreased and netrin-1 appeared in tubular epithelial cells. By 72 h after reperfusion, netrin-1 reappeared in the interstitium while tubular epithelial staining decreased significantly. Downregulation of netrin-1 in the interstitium corresponded with increased MCP-1 and IL-6 expression and infiltration of leukocytes into the reperfused kidney. Administration of recombinant netrin-1 significantly improved kidney function (blood urea nitrogen: 161 ± 7 vs. 104 ± 24 mg/dl, creatinine: 1.3 ± 0.07 vs. 0.75 ± 0.16 mg/dl, P < 0.05 at 24 h) and reduced tubular damage and leukocyte infiltration in the outer medulla. These results suggest that downregulation of netrin-1 in vascular endothelial cells may promote endothelial cell activation and infiltration of leukocytes into the kidney thereby enhancing tubular injury.
Amiloride restores renal medullary osmolytes in lithium-induced nephrogenic diabetes insipidus
Authors: Bedford Jennifer J. , Leader John P. , Jing Rena , Walker Logan J. , Klein Janet D. , Sands Jeff M. , Walker Robert J.
Published: January 2008

In lithium-induced nephrogenic diabetes insipidus (NDI), alterations in renal medullary osmolyte concentrations have been assumed but never investigated. Amiloride can modify lithium-induced NDI, but the impact of amiloride in lithium-induced NDI on renal medullary osmolytes, aquaporins, and urea transporters is unknown and is the basis of this study. Rats fed lithium (60 mmol/kg dry food) over 4 wk developed NDI. Urine osmolality fell to 287 ± 19 mosmol/kgH2O (controls 1,211 ± 90 mosmol/kgH2O). Organic osmolytes in the renal medulla showed significant decreases compared with controls [inositol 221 ± 35 to 85 ± 10 mmol/kg protein; sorbitol 35 ± 9 to 3 ± 1 mmol/kg protein; glycerophosphorylcholine (GPC) 352 ± 80 to 91 ± 20 mmol/kg protein; and glycine betaine 69 ± 11 to 38 ± 38 mmol/kg protein]. Medullary urea content fell from 2,868 ± 624 to 480 ± 117 mmol/kg protein. Concurrent administration of amiloride (0.2 mmol/l) in the drinking water restored urine osmolality (1,132 ± 154 mosmol/kgH2O), and reduced urine volume. Medullary osmolyte content were restored to control values (inositol, 232 ± 12; sorbitol 32 ± 6; GPC, 244 ± 26; glycine betaine, 84 ± 5 mmol/kg protein). Medullary urea rose to 2,122 ± 305 mmol/kg protein. Reduced AQP2, AQP3, and urea transporter (UT-A1) expression was significantly reversed following amiloride therapy. Data presented here provide further understanding of how amiloride may substantially restore the lithium-induced impaired renal concentrating mechanism.
Cerebrovascular responsiveness to steady-state changes in end-tidal CO2 during passive heat stress
Authors: Low David A. , Wingo Jonathan E. , Keller David M. , Davis Scott L. , Zhang Rong , Crandall Craig G.
Published: January 2008

This study tested the hypothesis that passive heat stress alters cerebrovascular responsiveness to steady-state changes in end-tidal CO2 (PetCO2). Nine healthy subjects (4 men and 5 women), each dressed in a water-perfused suit, underwent normoxic hypocapnic hyperventilation (decrease PetCO2 ∼20 Torr) and normoxic hypercapnic (increase in PetCO2 ∼9 Torr) challenges under normothermic and passive heat stress conditions. The slope of the relationship between calculated cerebrovascular conductance (CBVC; middle cerebral artery blood velocity/mean arterial blood pressure) and PetCO2 was used to evaluate cerebrovascular CO2 responsiveness. Passive heat stress increased core temperature (1.1 ± 0.2°C, P < 0.001) and reduced middle cerebral artery blood velocity by 8 ± 8 cm/s ( P = 0.01), reduced CBVC by 0.09 ± 0.09 CBVC units ( P = 0.02), and decreased PetCO2 by 3 ± 4 Torr ( P = 0.07), while mean arterial blood pressure was well maintained ( P = 0.36). The slope of the CBVC-PetCO2 relationship to the hypocapnic challenge was not different between normothermia and heat stress conditions (0.009 ± 0.006 vs. 0.009 ± 0.004 CBVC units/Torr, P = 0.63). Similarly, in response to the hypercapnic challenge, the slope of the CBVC-PetCO2 relationship was not different between normothermia and heat stress conditions (0.028 ± 0.020 vs. 0.023 ± 0.008 CBVC units/Torr, P = 0.31). These results indicate that cerebrovascular CO2 responsiveness, to the prescribed steady-state changes in PetCO2, is unchanged during passive heat stress.
Dendritic Ih Ensures High-Fidelity Dendritic Spike Responses of Motion-Sensitive Neurons in Rat Superior Colliculus
Authors: Endo Toshiaki , Tarusawa Etsuko , Notomi Takuya , Kaneda Katsuyuki , Hirabayashi Masumi , Shigemoto Ryuichi , Isa Tadashi
Published: January 2008

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels that generate Ih currents are widely distributed in the brain and have been shown to contribute to various neuronal functions. In the present study, we investigated the functions of Ih in the motion-sensitive projection neurons [wide field vertical (WFV) cells] of the superior colliculus, a pivotal visual center for detection of and orientating to salient objects. Combination of whole cell recordings and immunohistochemical investigations suggested that HCN1 channels dominantly contribute to the Ih in WFV cells among HCN isoforms expressed in the superficial superior colliculus and mainly located on their expansive dendritic trees. We found that blocking Ih suppressed the initiation of short- and fixed-latency dendritic spike responses and led instead to long- and fluctuating-latency somatic spike responses to optic fiber stimulations. These results suggest that the dendritic Ih facilitates the dendritic initiation and/or propagation of action potentials and ensures that WFV cells generate spike responses to distal synaptic inputs in a sensitive and robustly time-locked manner, probably by acting as continuous depolarizing drive and fixing dendritic membrane potentials close to the spike threshold. These functions are different from known functions of dendritic Ih revealed in hippocampal and neocortical pyramidal cells, where they spatiotemporally limit the propagations of synaptic inputs along the apical dendrites by reducing dendritic membrane resistance. Thus we have revealed new functional aspects of Ih, and these dendritic properties are likely critical for visual motion processing in these neurons.
Effects of Striatal GABAA-Receptor Blockade on Striatal and Cortical Activity in Monkeys
Authors: Darbin Olivier , Wichmann Thomas
Published: January 2008

To elucidate the role of ambient striatal γ-aminobutyric acid (GABA) in the regulation of neuronal activity in the basal ganglia–thalamocortical circuits, we studied the effects of blocking striatal GABAAreceptors on the electrical activities of single striatal neurons, on local field potentials (LFPs) in the striatum, and on motor cortical electroencephalograms (EEGs) in two monkeys. Striatal LFPs were recorded with a device that allowed us to simultaneously record field potentials and apply drugs by reverse microdialysis at the same site. Administration of the GABAA-receptor antagonist gabazine (SR95531, 10 and 500 μM) induced large-amplitude LFP fluctuations at the infusion site, occurring every 2–5 s for about 2 h after the start of the 20-min drug administration. These events were prevented by cotreatment with a GABAA-receptor agonist (muscimol, 100 μM) or a combination of ionotropic glutamate receptor antagonists (CNQX and MK-801, each given at 100 μM). Gabazine (10 μM) also increased the firing of single neurons recorded close to the injection site, but in most cases there was no correlation between single-neuron activity and the concomitantly recorded LFP signals from the same striatal region. In contrast, intrastriatal application of gabazine increased the correlation between striatal LFPs and EEG, and resulted in the appearance of recurrent EEG events that were temporally related to the striatal LFP events. These data provide evidence that a GABAergic “tone” in the monkey striatum controls the spontaneous activity of striatal neurons, as well as the level of striatal and cortical synchrony.
Global Bounds for Cocoercive Variational Inequalities
Authors: Jianghua Fan , Xiaoguo Wang
Published: January 2008

By using the strong monotonicity of the perturbed fixed-point map and the normal map associated with cocoercive variational inequalities, we establish two new global bounds measuring the distance between any point and the solution set for cocoercive variational inequalities.
Comparison of Inventory Systems with Service, Positive Lead-Time, Loss, and Retrial of Customers
Authors: Krishnamoorthy A. , Jose K. P.
Published: January 2008

We analyze and compare three (s,S) inventory systems with positive service time and retrial of customers. In all of these systems, arrivals of customers form a Poisson process and service times are exponentially distributed. When the inventory level depletes to s due to services, an order of replenishment is placed. The lead-time follows an exponential distribution. In model I, an arriving customer, finding the inventory dry or server busy, proceeds to an orbit with probability γ and is lost forever with probability (1−γ). A retrial customer in the orbit, finding the inventory dry or server busy, returns to the orbit with probability δ and is lost forever with probability (1−δ). In addition to the description in model I, we provide a buffer of varying (finite) capacity equal to the current inventory level for model II and another having capacity equal to the maximum inventory level S for model III. In models II and III, an arriving customer, finding the buffer full, proceeds to an orbit with probability γ and is lost forever with probability (1−γ). A retrial customer in the orbit, finding the buffer full, returns to the orbit with probability δ and is lost forever with probability (1−δ). In all these models, the interretrial times are exponentially distributed with linear rate. Using matrix-analytic method, we study these inventory models. Some measures of the system performance in the steady state are derived. A suitable cost function is defined for all three cases and analyzed using graphical illustrations.
Field and Temperature Gradients from Short Conductors in a Dissipative Medium
Authors: Balzano Quirino , Foster Kenneth R. , Sheppard Asher R.
Published: January 2008

This paper considers the specific absorption rate (SAR) in tissue of radiofrequency (RF) energy and temperature increases produced by RF currents on short conductors (0.03–0.1λ). We consider a cylindrical model in which a center-feeds, insulated antenna is embedded in tissue. We introduce a new method for the analytic evaluation of the fields in the cylindrical phantom taking advantage of the axial symmetry of the antenna and the tissue. Results of the analytical model are compared to results of numerical (finite difference time domain) simulations; in addition, the thermal response of the exposed material is calculated by finite element solution of the heat conduction equation. For model antennas of 1 to 3 cm total length with a feedpoint current of 10mA RMS at 900MHz, the maximum SAR (in tissue next to the antenna) is less than∼2.5W/kg. SAR decays rapidly with radial distance from the antenna (∼r−4for the 1cm antenna) and creates a steady-state temperature rise less than 0.05K at the location ofSARmax. Heat conduction causes the temperature to decline steeply with radius (depth into tissue).
Preparation of Powdery Carbon Nanotwist and Application to Printed Field Emitter
Authors: Hosokawa Yuji , Shiki Hajime , Shinohara Yuichiro , Yokota Masashi , Takikawa Hirofumi , Ina Takashi , Okada Fumio , Fujimura Yohei , Yamaura Tatsuo , Itoh Shigeo , Miura Koji , Yoshikawa Kazuo
Published: January 2008

In the present study, an automatic production system with sequencer control for the synthesis of carbon nanofibriform based on catalytic CVD using a substrate was developed. The carbon nanotwist (CNTw), which is one of the helical carbon nanofibers, was then synthesized in powdery form with anNi–SnO2-composed catalyst. The production rate was 5 400 times that of the conventional CVD system andNi–Cu–In2O3catalyst. The powdery CNTw was easily scraped off the substrate, then pasted with organic binder, and printed by a squeegee method on ITO glass substrate for an electron field emitter. The field emission performance was found to be better than that of the directly grown CNTw film in conventional CVD with Ni–Cu catalyst.
Open Quotient Measurements Based on Multiscale Product of Speech Signal Wavelet Transform
Authors: Bouzid Aïcha , Ellouze Noureddine
Published: January 2008

This paper describes a multiscale product method (MPM) for open quotient measure in voiced speech. The method is based on determining the glottal closing and opening instants. The proposed approach consists of making the products of wavelet transform of speech signal at different scales in order to enhance the edge detection and parameter estimation. We show that the proposed method is effective and robust for detecting speech singularity. Accurate estimation of glottal closing instants (GCIs) and opening instants (GOIs) is important in a wide range of speech processing tasks. In this paper, accurate estimation of GCIs and GOIs is used to measure the local open quotient (Oq) which is the ratio of the open time by the pitch period. Multiscale product operates automatically on speech signal; the reference electroglottogram (EGG) signal is used for performance evaluation. The ratio of good GCI detection is 95.5% and that of GOI is 76%. The pitch period relative error is 2.6% and the open phase relative error is 5.6%. The relative error measured on open quotient reaches 3% for the whole Keele database.
Is PPARβ/δa Retinoid Receptor?
Authors: Berry Daniel C. , Noy Noa
Published: January 2008

The broad ligand-binding characteristic of PPARβ/δhas long hampered identification of physiologically-meaningful ligands for the receptor. The observations that the activity of PPARβ/δis supported by fatty acid binding protein 5 (FABP5), which directly delivers ligands from the cytosol to the receptor, suggest thatbona fidePPARβ/δligands both activate the receptor, and trigger the nuclear translocation of FABP5. Using these criteria, it was recently demonstrated that all-trans-retinoic acid (RA), the activator of the classical retinoic acid receptor RAR, also serves as a ligand for PPARβ/δ. Partitioning of RA between its two receptors was found to be regulated by FABP5, which delivers it to PPARβ/δ, and cellular RA binding protein II (CRABP-II), which targets it to RAR. Consequently, RA activates PPARβ/δin cells that display a high FABP5/CRABP-II expression ratio. It remains to be clarified whether compounds other than RA may also serve as endogenous activators for this highly promiscuous protein.
Trench's Perturbation Theorem for Dynamic Equations
Authors: Bohner Martin , Stevic Stevo
Published: January 2008

We consider a nonoscillatory second-order linear dynamic equation on a time scale together with a linear perturbation of this equation and give conditions on the perturbation that guarantee that the perturbed equation is also nonoscillatory and has solutions that behave asymptotically like a recessive and dominant solutions of the unperturbed equation. As the theory of time scales unifies continuous and discrete analysis, our results contain as special cases results for corresponding differential and difference equations by William F. Trench.
Continuous Interpolation of Solution Sets of Lipschitzian Quantum Stochastic Differential Inclusions
Authors: Ayoola E. O. , Adeyeye John O.
Published: January 2008

Given any finite set of trajectories of a Lipschitzian quantum stochastic differential inclusion (QSDI), there exists a continuous selection from the complex-valued multifunction associated with the solution set of the inclusion, interpolating the matrix elements of the given trajectories. Furthermore, the difference of any two of such solutions is bounded in the seminorm of the locally convex space of solutions.
Rare Earth-Activated Silica-Based Nanocomposites
Authors: Armellini C. , Chiappini A. , Chiasera A. , Ferrari M. , Jestin Y. , Mortier M. , Moser E. , Retoux R. , Righini G. C.
Published: January 2008

Two different kinds of rare earth-activated glass-based nanocomposite photonic materials, which allow to tailor the spectroscopic properties of rare-earth ions: (i) Er3+-activated SiO2-HfO2waveguide glass ceramic, and (ii) core-shell-like structures of Er3+-activated silica spheres obtained by a seed growth method, are presented.
Thermal-Hydraulic Analysis of Coolant Flow Decrease in Fuel Channels of Smolensk-3 RBMK during GDH Blockage Event
Authors: Costa A. Lombardi , Cherubini M. , D'Auria F. , Giannotti W. , Moskalev A.
Published: January 2008

One of the transients that have received considerable attention in the safety evaluation of RBMK reactors is the partial break of a group distribution header (GDH). The coolant flow rate blockage in one GDH might lead to excessive heat-up of the pressure tubes and can result in multiple fuel channels (FC) ruptures. In this work, the GDH flow blockage transient has been studied considering the Smolensk-3 RBMK NPP (nuclear power plant). In the RBMK, each GDH distributes coolant to 40–43 FC. To investigate the behavior of each FC belonging to the damaged GDH and to have a more realistic trend, one (affected) GDH has been schematized with its forty-two FC, one by one. The calculations were performed using the 0-D NK (neutron kinetic) model of the RELAP5-3.3 stand-alone code. The results show that, during the event, the mass flow rate is disturbed differently according to the power distribution established for each FC in the schematization. The start time of the oscillations in mass flow rate depends strongly on the attributed power to each FC. It was also observed that, during the event, the fuel channels at higher thermal power values tend to undergo first cladding rupture leaving the reactor to scram and safeguarding all the other FCs connected to the affected GDH.
Semi-Hausdorff Fuzzy Filters
Authors: Nayagam V. Lakshmana Gomathi , Sivaraman Geetha
Published: January 2008

The notion of fuzzy filters was studied by Vicente and Aranguren (1988), Lowen (1979), and Ramakrishnan and Nayagam (2002). The notion of fuzzily compactness was introduced and studied by Ramakrishnan and Nayagam (2002). In this paper, an equivalent condition of fuzzily compactness is studied and a new notion of semi-Hausdorffness on fuzzy filters, which cannot be defined in crisp theory of filters, is introduced and studied.
GPS Composite Clock Analysis
Authors: Wright James R.
Published: January 2008

The GPS composite clock defines GPS time, the timescale used today in GPS operations. GPS time is illuminated by examination of its role in the complete estimation and control problem relative to UTC/TAI. The phase of each GPS clock is unobservable from GPS pseudorange measurements, and the mean phase of the GPS clock ensemble (GPS time) is unobservable. A new and useful observability definition is presented, together with new observability theorems, to demonstrate explicitly that GPS time is unobservable. Simulated GPS clock phase and frequency deviations, and simulated GPS pseudorange measurements, are used to understand GPS time in terms of Kalman filter estimation errors.
Cardiac PPARα Protein Expression is Constant as Alternate Nuclear Receptors and PGC‐1 Coordinately Increase During the Postnatal Metabolic Transition
Authors: Buroker Norman E. , Ning Xue-Han , Portman Michael
Published: January 2008

Gene expression data obtained in mouse heart indicate that increased expression for the nuclear receptor, peroxisomal proliferator activated receptor α (PPARα), prompts the postnatal transition from predominantly carbohydrate to fatty acid oxidation preference. However, no phenotypic or proteomic data are available to confirm downstream signaling and metabolic transition in mice. We studied the hypothesis that shifts in nuclear receptor expression trigger the newborn metabolic switch in a newborn sheep. This species is well characterized with regards to developmental changes in substrate oxidative metabolism. Heart tissues from fetal (130 days
gestation), newborn ≤24 hours, and 30‐day old lambs were evaluated for protein expression from multiple enzymes controlling oxidative metabolism as well as principal nuclear receptors and coactivators. Although muscle and liver type carnitine palmitoyl transferases I showed no significant changes to correspond to the metabolic transition, hexokinase II protein content
showed a profound transient drop, and pyruvate dehydrogenase kinase steadily increased. PPARα showed no increases preceding or during the transition, while peroxisomal proliferator activated receptor gamma coactivator‐1 (PGC‐1) increased approximately 20‐fold transiently in newborn heart in conjunction with significant increases in thyroid hormone receptor α1 and retinoid‐activated receptor α. These data challenge the paradigm that increases in PPARα prompt the postnatal metabolic switch, and suggest that other nuclear receptors play a major role. As thyroid hormone (TH) modulates PGC‐1 expression in sheep during development, these data further suggest that well‐characterized perinatal TH surge in sheep contributes to this metabolic switch.
Effect of Carbon Nanofiber‐Matrix Adhesion on Polymeric Nanocomposite Properties—Part II
Authors: Lafdi Khalid , Fox William , Matzek Matthew , Yildiz Emel
Published: January 2008

A successful integration of two independent phases with good adhesion is imperative for
effective translation of superior carbon nanofiber filler properties into a physically superior
carbon nanocomposite. Carbon nanofibers were subjected to electrochemical oxidation in 0.1 M
nitric acid for varying times. The strength of adhesion between the nanofiber and an epoxy matrix
was characterized by flexural strength and modulus. The surface functional groups
formed and their concentration of nanofibers showed a dependence on the degree of oxidation.
The addition of chemical functional groups on the nanofiber surface allows them to physically
and chemically adhere to the continuous resin matrix. The chemical interaction with the
continuous epoxy matrix results in the creation of an interphase region. The ability to chemically
and physically interact with the epoxy region is beneficial to the mechanical properties of a
carbon nanocomposite. A tailored degree of surface functionalization was found to increase
adhesion to the matrix and increase flexural modulus.
Analyses of Instability Events in the Peach Bottom-2 BWR Using Thermal-Hydraulic and 3D Neutron Kinetic Coupled Codes Technique
Authors: Lombardi Costa Antonella , Petruzzi Alessandro , D'Auria Francesco , Ambrosini Walter
Published: January 2008

Boiling water reactor (BWR) instabilities may occur when, starting from a stable operating condition, changes in system parameters bring the reactor towards an unstable region. In order to design more stable and safer core configurations, experimental and theoretical studies about BWR stability have been performed to characterise the phenomenon and to predict the conditions for its occurrence. In this work, contributions to the study of BWR instability phenomena are presented. The RELAP5/MOD3.3 thermal-hydraulic (TH) system code and the PARCS-2.4 3D neutron kinetic (NK) code were coupled to simulate BWR transients. Different algorithms were used to calculate the decay ratio (DR) and the natural frequency (NF) from the power oscillation predicted by the transient calculations as two typical parameters used to provide a quantitative description of instabilities. The validation of the code model set up for the Peach Bottom Unit 2 BWR plant is performed against low-flow stability tests (LFSTs). The four series of LFST have been performed during the first quarter of 1977 at the end of cycle 2 in Pennsylvania. The tests were intended to measure the reactor core stability margins at the limiting conditions used in design and safety analyses.
The Roles of PPARs in the Fetal Origins of Metabolic Health and Disease
Authors: Rees William D. , McNeil Christopher J. , Maloney Christopher A.
Published: January 2008

Beyond the short‐term effects on fertility, there is increasing evidence that obesity or the consumption of an inappropriate diet by the mother during pregnancy adversely affects the long‐term health of her offspring. PPAR and RXR isotypes are widely expressed in reproductive tissues and in the developing fetus. Through their interactions with fatty acids, they may mediate adaptive responses to the changes in the maternal diet. In the maturing follicle, PPAR‐γ has an important role in the granulosa cells that surround the maturing oocyte. After fertilisation, PPAR‐γ and PPAR‐β/δ are essential regulators of placentation and the subsequent development of key metabolic tissues such as skeletal muscle and adipose cells. Activation of PPAR‐γ and PPAR‐β/δ during fetal development has the potential to modify the growth and development of these tissues. PPAR‐α is expressed at low levels in the fetal liver, however, this expression may be important, as changes in the methylation of DNA in its promoter region are reported to take place during this period of development. This epigenetic modification then programmes subsequent expression. These findings suggest that two separate PPAR‐dependent mechanisms may be involved in the fetal adaptations to the maternal diet, one, mediated by PPAR‐γ and PPAR‐β/δ, regulating cell growth and differentiation; and another adapting long‐term lipid metabolism via epigenetic changes in PPAR‐α to optimise postnatal survival.
A Conceptual Framework for the Analysis of First‐Person Shooter Audio and its Potential Use for Game Engines
Authors: Grimshaw Mark , Schott Gareth
Published: January 2008

We introduce and describe a new conceptual framework for the design and analysis of audio for immersive first‐person shooter games, and discuss its potential implications for the development of the audio component of game engines. The framework was created in order to illustrate and acknowledge the direct role of in‐game audio in shaping player‐player interactions and in creating a sense of immersion in the game world.
Furthermore, it is argued that the relationship between player and sound is best conceptualized theoretically as an acoustic ecology.
Current game engines are capable of game world spatiality through acoustic shading, but the ideas presented here provide a framework to explore other immersive possibilities for game audio through real‐time synthesis.
Morphology and Properties of Aminosilane Grafted MWCNT/Polyimide Nanocomposites
Authors: Yuen Siu-Ming , Ma Chen-Chi M. , Chiang Chin-Lung , Teng Chih-Chun
Published: January 2008

This investigation presents a novel method for modifying multiwalled carbon nanotubes (MWCNTs). The morphology, electrical resistivity, and percolation threshold of MWCNT/Polyimide nanocomposites were studied. Acid‐modified MWCNTs reacted with (3‐aminopropyl)triethoxysilane by ionic bonding, and were then mixed with polyamic acid via imidization. TEM microphotographs reveal that silane‐grafted MWCNTs were connected to each other. The electrical resistivity of silane‐grafted MWCNT/polyimide decreased substantially below than that of acid‐treated MWCNTs when the
silane‐modified MWCNT content was lower than 2.4 wt%. The percolation threshold of the MWCNT/polyimide composites is 1.0 wt% for silane‐modified MWCNT and exceeds 7.0 wt% for acid‐modified MWCNT. The acid‐modified MWCNT/polyimide composites possess slightly higher glass transition temperatures than that of pure polyimide. The glass transition temperature of the polyimide increased significantly with silane‐modified MWCNT content. Tensile properties of the polyimide have been improved with the MWCNTs content.
Artificial Neural Network (ANN) Modeling for the Energy Absorption of Hot‐Rolled Plates in Charpy Impact Tests
Authors: Tan W. , Liu Z.Y. , Wu D. , Wang G.D.
Published: January 2008

In the present paper, a modeling for the energy absorption (CVN) at room temperature of hot‐rolled plates in Charpy V‐notch impact tests was investigated, in which an BP(Back Propagation) ANN (Artificial Neural Network) model with three layers was developed to take into considerations chemical compositions, processing parameters, yield strength, tensile strength and product thickness. The measured or predicted strength values have been used to predict the energy absorption in Charpy impact tests, both showing good agreements with the measured values. In order to compare the precision of the neural‐network methods in predicting CVN, linear regression analysis was performed by using the same data. Also, analyses were made for the effects of alloying elements, microstructure and processing parameters on CVN using ANN model, being consistent with the metallurgical rules. It concluded that the absorbed energy in Charpy impact tests for given steel compositions, processing parameters, strengths and plate thickness can be predicted by using the modeling.