bluuebunny/crossref_metadata_2025 huggingface dataset:
OBJECT CLASSIFICATION AND OCCLUSION HANDLING USING QUADRATIC FEATURE CORRELATION MODEL AND NEURAL NETWORKS
Authors: FAN NA
Published: March 2011

Occlusion handling is an old but important problem for the computer vision and pattern recognition community. Features from different objects may twist with each other, and any matched feature points may belong to different objects for many traditional object recognition algorithms. To recognize occlusions, we should not only match objects from different view points but also match features extracted from the same object. In this paper, we propose a method to consider these two perspectives simultaneously by encoding various types of features, such as geometry, color and texture relationships among feature points into a matrix and find the best quadratic feature correlation model to fit them. Experiments on our own built dataset and the publicly available PASCAL VOC dataset shows that, our method can robustly classify objects and handle occluded objects under large occlusions, and the performance is among the state-of-the-art.
NUMERICAL EVIDENCE OF SOLITON-MEDIATED ELECTRON PAIRING IN HEATED ANHARMONIC CRYSTAL LATTICES
Authors: VELARDE M. G. , EBELING W. , CHETVERIKOV A. P.
Published: March 2011

Soliton-mediated electron pairing (both in real space and in momentum space) is shown to occur in heated one-dimensional (1D) molecular anharmonic systems with Morse interactions.
THE STRUCTURE OF ARNOLD TONGUE OVERLAPS IN DUFFING EQUATION WITHOUT SMALL PARAMETERS
Authors: LIU YANBIN , CHEN YUSHU , CAO QINGJIE
Published: March 2011

Duffing equation is a representative nonlinear equation in practical engineering systems, where the most existing research focuses on local solutions of weakly nonlinear systems. In this paper, we study global bifurcations and chaos of the standard Duffing system by employing the Arnold tongue, and use the basin of attraction to investigate the properties of the Arnold tongue overlap. Our results show that a resonance solution and chaos could coexist, when the parameters are on the Arnold tongue overlap. The phenomenon does not exist in a system described by a weak Duffing equation. Numerical solutions for these bifurcations and chaos are also provided to demonstrate the theoretical results.
STABILITY OF STEADY STATES AND EXISTENCE OF TRAVELING WAVES FOR A HOST-VECTOR EPIDEMIC
Authors: WU CHUFEN , WENG PEIXUAN
Published: March 2011

We study the stability of steady states and establish the existence of traveling waves for a diffusive host-vector epidemic with a nonlocal spatiotemporal interaction. We develop the techniques of contracting-convex-sets, limit argument, singular perturbation and fixed point theorems.
HUFFMAN CODING AS A NONLINEAR DYNAMICAL SYSTEM
Authors: NAGARAJ NITHIN
Published: March 2011

In this paper, source coding or data compression is viewed as a measurement problem. Given a measurement device with fewer states than the observable of a stochastic source, how can one capture their essential information? We propose modeling stochastic sources as piecewise-linear discrete chaotic dynamical systems known as Generalized Luröth Series (GLS) which has its roots in Georg Cantor's work in 1869. These GLS are special maps with the property that their Lyapunov exponent is equal to the Shannon's entropy of the source (up to a constant of proportionality). By successively approximating the source with GLS having fewer states (with the nearest Lyapunov exponent), we derive a binary coding algorithm which turns out to be a rediscovery of Huffman coding, the popular lossless compression algorithm used in the JPEG international standard for still image compression.
LOGISTIC MAP WITH A FIRST ORDER FILTER
Authors: HOLOPAINEN RISTO
Published: March 2011

A lowpass filter inserted into the logistic map stabilizes fixed points of the system for large parameter ranges and increases the range of global stability. With a first order filter we encounter a special case of the general 2-D quadratic map with hyperchaos in parts of its parameter ranges. Filtered maps include some maps with delayed variables, and here we present one of the simplest examples of such a system.
MAXIMUM ENTROPY METHOD FOR POSITION DEPENDENT RANDOM MAPS
Authors: ISLAM MD SHAFIQUL
Published: March 2011

Let {τ1, τ2,…,τK} be a collection of nonsingular maps on [0, 1] into [0, 1] and {p1, p2,…,pK} be a collection of position dependent probabilities on [0, 1]. We consider position dependent random maps T = {τ1,τ2,…,τK;p1,p2,…,pK} such that T preserves an absolutely continuous invariant measure with density f*. A maximum entropy method for approximating f* is developed. We present a proof of convergence of the maximum entropy method for random maps.
PRICING DIGITAL OUTPERFORMANCE OPTIONS WITH UNCERTAIN CORRELATION
Authors: MARABEL JACINTO
Published: March 2011

Multi-asset options exhibit sensitivity to the correlations between the underlying assets and these correlations are notoriously unstable. Moreover, some of these options such as the digital outperformance options, have a cross-gamma that changes sign depending on the relative evolution of the underlying assets. In this paper, I present a model to price digital outperformance options when there is uncertainty about correlation, but it is assumed to lie within a certain range. Under the assumption that assets prices follow a Geometric Brownian motion with constant instantaneous volatilities I present an analytic expression for the price of the digital outperformance option under the constant correlation assumption, as well as the partial differential equation corresponding to the uncertain correlation model. The comparison of the prices obtained using both models shows that there is no constant correlation which allows attaining the price obtained under the uncertain correlation model. This fact shows that it can be dangerous to assume a constant instantaneous correlation for products with a cross-gamma that changes sign.
THE COMPATIBLE BOND-STOCK MARKET WITH JUMPS
Authors: XIONG DEWEN , KOHLMANN MICHAEL
Published: March 2011

We construct a bond-stock market composed of d stocks and many bonds with jumps driven by general marked point process as well as by an ℝn-valued Wiener process. By composing these tools we introduce the concept of a compatible bond-stock market and give a necessary and sufficient condition for this property. We study no-arbitrage properties of the composed market where a compatible bond-stock market is arbitrage-free both for the bonds market and for the stocks market.

We then turn to an incomplete compatible bond-stock market and give a necessary and sufficient condition for a compatible bond-stock market to be incomplete. In this market we consider the mean-variance hedging in the special situation where both B(u, T) and eG(u, y, T)-1 are quadratic functions of T - u. So, we need to extend the notion of a variance-optimal martingale (VOM) as in Xiong and Kohlmann (2009) to the more general market. By introducing two virtual stocks [Formula: see text], we prove that the VOM for the bond-stock market is the same as the VOM for the new stock market [Formula: see text]. The mean-variance hedging problem in this incomplete bond-stock market for a contingent claim [Formula: see text] is solved by deriving an explicit solution of the optimal measure-valued strategy and the optimal cost induced by the optimal strategy of MHV for the stocks [Formula: see text] is computed.
Temperature Insensitive Clock Buffer and Its Application on Clock Tree
Authors: Tie Meng , Li Xia
Published: March 2011

High power density and uneven power density distribution caused large thermal space gradient on VLSI. Since CMOS gate delay is highly relevant to temperature, the thermal gradient could impact the performance of IC by increasing clock tree skew on chip. To maintain circuit performance, we utilize thermal behavior discrepancy between P and N type CMOS transistors to reduce clock skew under this circumstance. First, this paper proposes a kind of temperature insensitive clock buffer with cross-coupled structure. Second, a clock tree is then built based on proposed buffer to reduce clock skew induced by thermal gradient. Unlike traditional methods, the proposed circuit can work under normal supply voltage and no special voltage converter is needed.
Review of Silicon Nanowire Oxidation
Authors: Shi Xiaoping , Kurstjens Rufi , Vos Ingrid , Everaert Jean-Luc , Schaekers Marc
Published: March 2011

Silicon nanowires (SNWs) have recently attracted a lot of interest due to its explosive potential for nanoelectronic applications. To materialize these applications, the key role of thermal oxidation behavior of SNWs must be thoroughly understood. In the first half of the paper we review the results on SNW oxidation published up to date. It is commonly observed that SNW oxidation shows a retarded oxidation rate and stronger temperature dependence compared to those of planar Si; in addition, the SNW oxide thickness is also a strong function of SNW diameter. In the second half, we report our results on the SNW oxidation using an in-situ steam generation (ISSG) approach. ISSG oxidation is applied to oxidize the SNWs generated by a top-down lithography-etch approach, as an important technique to reduce the SNW diameter below 10nm. It is found that SNW oxidation with ISSG also exhibits a retared oxidation compared to that of planar Si using the same ISSG process, and a less dependance on SNW sizes than furnace SNW oxidation.
Cost-Effective and Accurate Solution for Jitter Performance Test in High-Speed Serial Links
Authors: Lu Ming
Published: March 2011

With the increasing demand for faster data communication, the data rate of communication systems has reached in the gigahertz range and higher. To accurately quantifying the transmission quality of high-speed I/Os with acceptable test time in production becomes one big challenge to ATE test engineers. The major hindrance is to fully measure jitter related specs accurately will lead to excessive cost of test (e.g., capital investment, time-to-market, test time), while BIST loopback testing can not promise a result with a high confidence level. This paper proposes one comprehensive solution for at-speed jitter performance testing on ATE, which includes jitter histogram testing, random jitter / deterministic jitter separation and jitter stardust testing. This solution has been implemented in volume production of a real device and the result shows its high accuracy and cost effectiveness.
Spectroscopic Characterization of AlGaN Samples Emitting in Deep-UV Region
Authors: Hannah Mark , Mishra Kailash C. , Laski Joe , Fareed Q. , Khan Asif
Published: April 2011

We have investigated optical and fluorescence properties of two epilayers used in a typical AlGaN based light emitting diode for emission in the deep ultraviolet (UV) region near 260 nm. These two epilayers correspond to one n-type AlGaN: Si layer used as the cladding layer, and a multiple quantum well system configured for emission near 272 nm respectively. The emission and excitation peaks for band edge emission have been thoroughly investigated. A strong temperature dependence of both visible and UV emission has been observed, and a model based on the Arrhenius equation was used to determine the activation energies for the states involved.
Ca2+ signaling in the regulation of dendritic cell functions
Authors: Shumilina Ekaterina , Huber Stephan M. , Lang Florian
Published: March 2011

Dendritic cells (DCs) are highly versatile antigen-presenting cells critically involved in both innate and adaptive immunity as well as maintenance of self-tolerance. DC function is governed by Ca2+ signaling, which directs the DC responses to diverse antigens, including Toll-like receptor ligands, intact bacteria, and microbial toxins. Ca2+-sensitive DC functions include DC activation, maturation, migration, and formation of immunological synapses with T cells. Moreover, alterations of cytosolic Ca2+ trigger immune suppression or switch off DC activity. Ca2+ signals are generated by the orchestration of Ca2+ transport processes across plasma, endoplasmic reticulum, and inner mitochondrial membrane. These processes include active pumping of Ca2+, Ca2+/Na+ antiport, and electrodiffusion through Ca2+-permeable channels or uniporters. Ca2+ channels in the plasma membrane such as Ca2+ release-activated Ca2+ or L-type Ca2+ channels are tightly regulated by the membrane potential which in turn depends on the activity of voltage-gated K+ or Ca2+-activated nonselective cation channels. The rapidly growing knowledge on the function and regulation of these membrane transport proteins provides novel insight into pathophysiological mechanisms underlying dysfunction of the immune system and opens novel therapeutic opportunity to favorably influence the function of the immune system.
Calcium entry through slow-inactivating L-type calcium channels preferentially triggers endocytosis rather than exocytosis in bovine chromaffin cells
Authors: Rosa Juliana M. , Torregrosa-Hetland Cristina J. , Colmena Inés , Gutiérrez Luis M. , García Antonio G. , Gandía Luis
Published: March 2011

Calcium (Ca2+)-dependent endocytosis has been linked to preferential Ca2+ entry through the L-type (α1D, CaV1.3) of voltage-dependent Ca2+ channels (VDCCs). Considering that the Ca2+-dependent exocytotic release of neurotransmitters is mostly triggered by Ca2+ entry through N-(α1B, CaV2.2) or PQ-VDCCs (α1A, CaV2.1) and that exocytosis and endocytosis are coupled, the supposition that the different channel subtypes are specialized to control different cell functions is attractive. Here we have explored this hypothesis in primary cultures of bovine adrenal chromaffin cells where PQ channels account for 50% of Ca2+ current ( ICa), 30% for N channels, and 20% for L channels. We used patch-clamp and fluorescence techniques to measure the exo-endocytotic responses triggered by long depolarizing stimuli, in 1, 2, or 10 mM concentrations of extracellular Ca2+ ([Ca2+]e). Exo-endocytotic responses were little affected by ω-conotoxin GVIA (N channel blocker), whereas ω-agatoxin IVA (PQ channel blocker) caused 80% blockade of exocytosis as well as endocytosis. In contrast, nifedipine (L channel blocker) only caused 20% inhibition of exocytosis but as much as 90% inhibition of endocytosis. Conversely, FPL67146 (an activator of L VDCCs) notably augmented endocytosis. Photoreleased caged Ca2+ caused substantially smaller endocytotic responses compared with those produced by K+ depolarization. Using fluorescence antibodies, no colocalization between L, N, or PQ channels with clathrin was found; a 20–30% colocalization was found between dynamin and all three channel antibodies. This is incompatible with the view that L channels are coupled to the endocytotic machine. Data rather support a mechanism implying the different inactivation rates of L (slow-inactivating) and N/PQ channels (fast-inactivating). Thus a slow but more sustained Ca2+ entry through L channels could be a requirement to trigger endocytosis efficiently, at least in bovine chromaffin cells.
Determinants of valve gating in collecting lymphatic vessels from rat mesentery
Authors: Davis Michael J. , Rahbar Elaheh , Gashev Anatoliy A. , Zawieja David C. , Moore James E.
Published: April 2011

Secondary lymphatic valves are essential for minimizing backflow of lymph and are presumed to gate passively according to the instantaneous trans-valve pressure gradient. We hypothesized that valve gating is also modulated by vessel distention, which could alter leaflet stiffness and coaptation. To test this hypothesis, we devised protocols to measure the small pressure gradients required to open or close lymphatic valves and determine if the gradients varied as a function of vessel diameter. Lymphatic vessels were isolated from rat mesentery, cannulated, and pressurized using a servo-control system. Detection of valve leaflet position simultaneously with diameter and intraluminal pressure changes in two-valve segments revealed the detailed temporal relationships between these parameters during the lymphatic contraction cycle. The timing of valve movements was similar to that of cardiac valves, but only when lymphatic vessel afterload was elevated. The pressure gradients required to open or close a valve were determined in one-valve segments during slow, ramp-wise pressure elevation, either from the input or output side of the valve. Tests were conducted over a wide range of baseline pressures (and thus diameters) in passive vessels as well as in vessels with two levels of imposed tone. Surprisingly, the pressure gradient required for valve closure varied >20-fold (0.1–2.2 cmH2O) as a passive vessel progressively distended. Similarly, the pressure gradient required for valve opening varied sixfold with vessel distention. Finally, our functional evidence supports the concept that lymphatic muscle tone exerts an indirect effect on valve gating.
α1-Adrenoreceptor activity does not explain lower morning endothelial-dependent, flow-mediated dilation in humans
Authors: Jones Helen , Lewis Nia C. S. , Green Daniel J. , Ainslie Philip N. , Lucas Samuel J. E. , Tzeng Yu-Chieh , Grant Emily J. M. , Atkinson Greg
Published: March 2011

Early morning reduction in endothelium-dependent, flow-mediated dilation (FMD) may contribute to the high incidence of sudden cardiac death at this time of day. The mechanisms underpinning diurnal variation in FMD are unclear, but potentially relate to a circadian rhythm in sympathetic nerve activity. We hypothesized that blockade of α1-mediated sympathetic nerve activity would act to attenuate the diurnal variation in FMD. In a randomized and placebo-controlled design, we measured brachial artery FMD in 12 participants (mean age = 26 yr, SD = 3) at 0600 and 1600 after ingestion of an α1-blocker (prazosin, 1 mg/20 kg body mass) or placebo. Arterial diameter and shear rate were assessed using edge-detection software. Heart rate and blood pressure were also measured. Data were analyzed using linear mixed modeling. Following placebo, FMD was 8 ± 2% in the morning compared with 10 ± 3% in the afternoon ( P = 0.04). Blockade with prazosin led to a slight but nonsignificant increase in morning FMD ( P = 0.24) and a significant ( P = 0.04) decrease in afternoon FMD, resulting in no diurnal variation ( P = 0.20). Shear rate did not differ in the morning or afternoon under either condition ( P > 0.23). Blood pressure was lower following prazosin compared with placebo ( P < 0.02), an effect that was similar at both times of day ( P > 0.34). Heart rate and norepinephrine levels were higher in the afternoon following prazosin. These data indicate that α1-adrenoreceptor activity does not explain lower morning endothelium-dependent FMD.
Ion regulation in fish gills: recent progress in the cellular and molecular mechanisms
Authors: Hwang Pung-Pung , Lee Tsung-Han , Lin Li-Yih
Published: March 2011

Fish encounter harsh ionic/osmotic gradients on their aquatic environments, and the mechanisms through which they maintain internal homeostasis are more challenging compared with those of terrestrial vertebrates. Gills are one of the major organs conducting the internal ionic and acid-base regulation, with specialized ionocytes as the major cells carrying out active transport of ions. Exploring the iono/osmoregulatory mechanisms in fish gills, extensive literature proposed several models, with many conflicting or unsolved issues. Recent studies emerged, shedding light on these issues with new opened windows on other aspects, on account of available advanced molecular/cellular physiological approaches and animal models. Respective types of ionocytes and ion transporters, and the relevant regulators for the mechanisms of NaCl secretion, Na+uptake/acid secretion/NH4+excretion, Ca2+uptake, and Cl−uptake/base secretion, were identified and functionally characterized. These new ideas broadened our understanding of the molecular/cellular mechanisms behind the functional modification/regulation of fish gill ion transport during acute and long-term acclimation to environmental challenges. Moreover, a model for the systematic and local carbohydrate energy supply to gill ionocytes during these acclimation processes was also proposed. These provide powerful platforms to precisely study transport pathways and functional regulation of specific ions, transporters, and ionocytes; however, very few model species were established so far, whereas more efforts are needed in other species.
Similar mitochondrial activation kinetics in wild-type and creatine kinase-deficient fast-twitch muscle indicate significant Pi control of respiration
Authors: Jeneson Jeroen A. L. , ter Veld Frank , Schmitz Joep P. J. , Meyer Ronald A. , Hilbers Peter A. J. , Nicolay Klaas
Published: March 2011

Past simulations of oxidative ATP metabolism in skeletal muscle have predicted that elimination of the creatine kinase (CK) reaction should result in dramatically faster oxygen consumption dynamics during transitions in ATP turnover rate. This hypothesis was investigated. Oxygen consumption of fast-twitch (FT) muscle isolated from wild-type (WT) and transgenic mice deficient in the myoplasmic (M) and mitochondrial (Mi) CK isoforms (MiM CK−/−) were measured at 20°C at rest and during electrical stimulation. MiM CK−/− muscle oxygen consumption activation kinetics during a step change in contraction rate were 30% faster than WT (time constant 53 ± 3 vs. 69 ± 4 s, respectively; mean ± SE, n = 8 and 6, respectively). MiM CK−/− muscle oxygen consumption deactivation kinetics were 380% faster than WT (time constant 74 ± 4 s vs. 264 ± 4 s, respectively). Next, the experiments were simulated using a computational model of the oxidative ATP metabolic network in FT muscle featuring ADP and Pi feedback control of mitochondrial respiration (J. A. L. Jeneson, J. P. Schmitz, N. A. van den Broek, N. A. van Riel, P. A. Hilbers, K. Nicolay, J. J. Prompers. Am J Physiol Endocrinol Metab 297: E774–E784, 2009) that was reparameterized for 20°C. Elimination of Pi control via clamping of the mitochondrial Pi concentration at 10 mM reproduced past simulation results of dramatically faster kinetics in CK−/− muscle, while inclusion of Pi control qualitatively explained the experimental observations. On this basis, it was concluded that previous studies of the CK-deficient FT muscle phenotype underestimated the contribution of Pi to mitochondrial respiratory control.
TLR3-dependent regulation of cytokines in human mesangial cells: a novel role for IP-10 and TNF-α in hepatitis C-associated glomerulonephritis
Authors: Merkle Monika , Ribeiro Andrea , Wörnle Markus
Published: March 2011

In viral infections, disease manifestations and tissue damage often result primarily from immune cells infiltrating target organs on the basis of an ineffectual viral clearance with persistent antigenemia or an inappropriate immune response. Cell types and mediators defining these inflammatory processes are still inadequately understood. In hepatitis C virus-associated glomerulonephritis, analysis of interferon-γ-inducible protein (IP-10) as a chemokine centrally involved in early antiviral response and TNF-α known to balance proinflammatory and immunosuppressive effects in inflammation shows a significant upregulation of both IP-10 and TNF-α mediated specifically by the viral receptor Toll-like receptor 3 expressed on mesangial cells. IP-10 induction is further potentiated by TNF-α signaling, preferentially via the TNF-α receptor subtype 2 selectively increased upon stimulation of viral receptors in the proinflammatory milieu.
Midbrain and medullary control of postinspiratory activity of the crural and costal diaphragm in vivo
Authors: Subramanian Hari H. , Holstege Gert
Published: March 2011

Studies on brain stem respiratory neurons suggest that eupnea consists of three phases: inspiration, postinspiration, and expiration. However, it is not well understood how postinspiration is organized in the diaphragm, i.e., whether postinspiration differs in the crural and costal segments of the diaphragm and what the influence is of postinspiratory neurons on diaphragm function during eupnea. In this in vivo study we investigated the postinspiratory activity of the two diaphragm segments during eupnea and the changes in diaphragm function following modulation of eupnea. Postinspiratory neurons in the medulla were stereotaxically localized extracellularly and neurochemically stimulated. We used three types of preparations: precollicularly decerebrated unanesthetized cats and rats and anesthetized rats. In all preparations, during eupnea, postinspiratory activity was found in the crural but not in the costal diaphragm. When eupnea was discontinued in decerebrate cats in which stimulation in the nucleus retroambiguus induced activation of laryngeal or abdominal muscles, all postinspiratory activity in the crural diaphragm was abolished. In decerebrate rats, stimulation of the midbrain periaqueductal gray abolished postinspiration in the crural diaphragm but induced activation in the costal diaphragm. In anesthetized rats, stimulation of medullary postinspiratory neurons abolished the postinspiratory activity of the crural diaphragm. Vagal nerve stimulation in these rats increased the intensity of postinspiratory neuronal discharge in the solitary nucleus, leading to decreased activity of the crural diaphragm. These data demonstrate that three-phase breathing in the crural diaphragm during eupnea exists in vivo and that postinspiratory neurons have an inhibitory effect on crural diaphragm function.
Changes of the force-frequency relationship in the rat medial gastrocnemius muscle after total transection and hemisection of the spinal cord
Authors: Mrówczyński Włodzimierz , Celichowski Jan , Krutki Piotr , Cabaj Anna , Sławińska Urszula , Majczyński Henryk
Published: March 2011

The relationships between the stimulation frequency and the force developed by motor units (MUs) of the medial gastrocnemius muscle were compared between intact rats and animals after total transection or hemisection of the spinal cord at the low thoracic level. The experiments on functionally isolated MUs were carried out 14, 30, 90, and 180 days after the spinal cord injury. Axons of investigated MUs were stimulated with trains of pulses at 10 progressively increased frequencies (from 1 to 150 Hz), and the force-frequency curves were plotted. Spinal cord hemisection resulted in a considerable leftward shift of force-frequency curves in all types of MUs. After the total transection, a leftward shift of the curve was observed in fast MUs, whereas there was a rightward shift in slow MUs. These changes coincided with a decrease of stimulation frequencies necessary to evoke 60% of maximal force. Moreover, the linear correlation between these stimulation frequencies and the twitch contraction time observed in intact rats was disrupted in all groups of animals with spinal cord injury. The majority of the observed changes reached the maximum 1 mo after injury, whereas the effects evoked by spinal cord hemisection were significantly smaller and nearly constant in the studied period. The results of this study can be important for the prediction of changes in force regulation in human muscles after various extends of spinal cord injury and in evaluation of the frequency of functional electrical stimulation used for training of impaired muscles.
Postnatal development of A-type and Kv1- and Kv2-mediated potassium channel currents in neocortical pyramidal neurons
Authors: Guan Dongxu , Horton Leslie R. , Armstrong William E. , Foehring Robert C.
Published: March 2011

Potassium channels regulate numerous aspects of neuronal excitability, and several voltage-gated K+channel subunits have been identified in pyramidal neurons of rat neocortex. Previous studies have either considered the development of outward current as a whole or divided currents into transient, A-type and persistent, delayed rectifier components but did not differentiate between current components defined by α-subunit type. To facilitate comparisons of studies reporting K+currents from animals of different ages and to understand the functional roles of specific current components, we characterized the postnatal development of identified Kv channel-mediated currents in pyramidal neurons from layers II/III from rat somatosensory cortex. Both the persistent/slowly inactivating and transient components of the total K+current increased in density with postnatal age. We used specific pharmacological agents to test the relative contributions of putative Kv1- and Kv2-mediated currents (100 nM α-dendrotoxin and 600 nM stromatoxin, respectively). A combination of voltage protocol, pharmacology, and curve fitting was used to isolate the rapidly inactivating A-type current. We found that the density of all identified current components increased with postnatal age, approaching a plateau at 3–5 wk. We found no significant changes in the relative proportions or kinetics of any component between postnatal weeks 1 and 5, except that the activation time constant for A-type current was longer at 1 wk. The putative Kv2-mediated component was the largest at all ages. Immunocytochemistry indicated that protein expression for Kv4.2, Kv4.3, Kv1.4, and Kv2.1 increased between 1 wk and 4–5 wk of age.
Increased persistent Na+current contributes to seizure in the slamdance bang-sensitiveDrosophilamutant
Authors: Marley Richard , Baines Richard A.
Published: March 2011

There is clinical need to extend the understanding of epilepsy and to find novel approaches to treat this condition. Bang-sensitive (bs) Drosophila mutants, which exhibit reduced thresholds for seizure, offer an attractive possibility to combine tractable genetics, electrophysiology, and high-throughput screening. However, despite these advantages, the precise electrophysiological aberrations that contribute to seizure have not been identified in any bs mutant. Because of this, the applicability of Drosophila as a preclinical model has not yet been established. In this study, we show that electroshock of bs slamdance ( sda) larvae was sufficient to induce extended seizure-like episodes. Whole cell voltage-clamp recordings from identified motoneurons (termed aCC and RP2) showed synaptic currents that were greatly increased in both amplitude and duration. Current-clamp recordings indicated that these inputs produced longer-lived plateau depolarizations and increased action potential firing in these cells. An analysis of voltage-gated currents in these motoneurons, in both first and third instar larvae, revealed a consistently increased persistent Na+current ( INap) and a reduced Ca2+current in first instar larvae, which appeared normal in older third instar larvae. That increased INapmay contribute to seizure-like activity is indicated by the observation that feeding sda larvae the antiepileptic drug phenytoin, which was sufficient to reduce INap, rescued both seizure-like episode duration and synaptic excitation of motoneurons. In contrast, feeding of either anemone toxin, a drug that preferentially increases INap, or phenytoin to wild-type larvae was sufficient to induce a bs behavioral phenotype. Finally, we show that feeding of phenytoin to gravid sda females was sufficient to both reduce INapand synaptic currents and rescue the bs phenotype in their larval progeny, indicating that a heightened predisposition to seizure may arise as a consequence of abnormal embryonic neural development.
Neurochemical excitation of propriospinal neurons facilitates locomotor command signal transmission in the lesioned spinal cord
Authors: Zaporozhets Eugene , Cowley Kristine C. , Schmidt Brian J.
Published: March 2011

Previous studies of the in vitro neonatal rat brain stem-spinal cord showed that propriospinal relays contribute to descending transmission of a supraspinal command signal that is capable of activating locomotion. Using the same preparation, the present series examines whether enhanced excitation of thoracic propriospinal neurons facilitates propagation of the locomotor command signal in the lesioned spinal cord. First, we identified neurotransmitters contributing to normal endogenous propriospinal transmission of the locomotor command signal by testing the effect of receptor antagonists applied to cervicothoracic segments during brain stem-induced locomotor-like activity. Spinal cords were either intact or contained staggered bilateral hemisections located at right T1/T2 and left T10/T11 junctions designed to abolish direct long-projecting bulbospinal axons. Serotonergic, noradrenergic, dopaminergic, and glutamatergic, but not cholinergic, receptor antagonists blocked locomotor-like activity. Approximately 73% of preparations with staggered bilateral hemisections failed to generate locomotor-like activity in response to electrical stimulation of the brain stem alone; such preparations were used to test the effect of neuroactive substances applied to thoracic segments (bath barriers placed at T3 and T9) during brain stem stimulation. The percentage of preparations developing locomotor-like activity was as follows: 5-HT (43%), 5-HT/ N-methyl-d-aspartate (NMDA; 33%), quipazine (42%), 8-hydroxy-2-(di- n-propylamino)tetralin (20%), methoxamine (45%), and elevated bath K+concentration (29%). Combined norepinephrine and dopamine increased the success rate (67%) compared with the use of either agent alone (4 and 7%, respectively). NMDA, Mg2+ion removal, clonidine, and acetylcholine were ineffective. The results provide proof of principle that artificial excitation of thoracic propriospinal neurons can improve supraspinal control over hindlimb locomotor networks in the lesioned spinal cord.
Both visual and idiothetic cues contribute to head direction cell stability during navigation along complex routes
Authors: Yoder Ryan M. , Clark Benjamin J. , Brown Joel E. , Lamia Mignon V. , Valerio Stephane , Shinder Michael E. , Taube Jeffrey S.
Published: March 2011

Successful navigation requires a constantly updated neural representation of directional heading, which is conveyed by head direction (HD) cells. The HD signal is predominantly controlled by visual landmarks, but when familiar landmarks are unavailable, self-motion cues are able to control the HD signal via path integration. Previous studies of the relationship between HD cell activity and path integration have been limited to two or more arenas located in the same room, a drawback for interpretation because the same visual cues may have been perceptible across arenas. To address this issue, we tested the relationship between HD cell activity and path integration by recording HD cells while rats navigated within a 14-unit T-maze and in a multiroom maze that consisted of unique arenas that were located in different rooms but connected by a passageway. In the 14-unit T-maze, the HD signal remained relatively stable between the start and goal boxes, with the preferred firing directions usually shifting <45° during maze traversal. In the multiroom maze in light, the preferred firing directions also remained relatively constant between rooms, but with greater variability than in the 14-unit maze. In darkness, HD cell preferred firing directions showed marginally more variability between rooms than in the lighted condition. Overall, the results indicate that self-motion cues are capable of maintaining the HD cell signal in the absence of familiar visual cues, although there are limits to its accuracy. In addition, visual information, even when unfamiliar, can increase the precision of directional perception.
Effect of the Japanese Herbal Kampo Medicine Dai‐Kenchu‐To on Postoperative Adhesive Small Bowel Obstruction Requiring Long‐Tube Decompression: A Propensity Score Analysis
Authors: Yasunaga Hideo , Miyata Hiroaki , Horiguchi Hiromasa , Kuwabara Kazuaki , Hashimoto Hideki , Matsuda Shinya
Published: March 2011

Adhesive small bowel obstruction (ASBO) is an adverse consequence of abdominal surgery. Although the Kampo medicine Dai‐kenchu‐to is widely used in Japan for treatment of postoperative ASBO, rigorous clinical studies for its use have not been performed. In the present retrospective observational study using the Japanese diagnosis procedure combination inpatient database, we selected 288 propensity‐score‐matched patients with early postoperative ASBO following colorectal cancer surgery, who received long‐tube decompression (LTD) with or without Dai‐kenchu‐to administration. The success rates of LTD were not significantly different between Dai‐kenchu‐to users and nonusers (84.7% versus 78.5%; P = .224), while Dai‐kenchu‐to users showed a shorter duration of LTD (8 versus 10 days; P = .012), shorter duration between long‐tube insertion and discharge (23 versus 25 days; P = .018), and lower hospital charges ($23,086 versus $26,950; P = .018) compared with Dai‐kenchu‐to nonusers. In conclusion, the present study suggests that Dai‐kenchu‐to is effective for reducing the duration of LTD and saving costs.
The Conformation and Assignment of the Proton NMR Spectrum in Water of DX600, a Bioactive Peptide with a Random Coil Conformation
Authors: Steinmetz Wayne E. , Carrell Timothy N. , Peprah Richard B.
Published: March 2011

DX600, a small peptide with 26 residues, is a potent, highly selective inhibitor of angiotensin converting enzyme 2 (ACE2). A range of NMR methods including TOCSY and ROESY yield an assignment of its proton spectrum in water and constraints on its conformation. Constrained molecular dynamics simulations of solvated DX600 show that the peptide′s most abundant conformer adopts a predominantly random coil conformation. Constrained by the disulfide bond, its backbone defines an overhand knot with frayed ends.
Helminth Community Dynamics in Populations of Blue-Winged Teal (Anas discors) Using Two Distinct Migratory Corridors
Authors: Garvon Jason M. , Fedynich Alan M. , Peterson Markus J. , Pence Danny B.
Published: March 2011

The influence of spatially distinct host subpopulations on helminth community structure and pattern was examined in a migratory avian host species. Forty helminth species represented by 24,082 individuals were collected from 184 blue-winged teal (Anas discors; BWT) from 2 primary migratory corridors in Florida (eastern migratory corridor; EMC) and Louisiana and Texas (western migratory corridor; WMC). Mean species richness was greater in BWT from the WMC (x¯±S.E=10.2 ± 0.3species) than the EMC (8.6 ± 0.2). The helminth community from the WMC had higher abundances of 6 common/intermediate species. Corridor helminth communities were similar in species composition but less similar when incorporating abundances of those species. Overlapping distributions of phylogenetically related host species that share generalist helminth species across ecologically similar habitats seem to mitigate the isolating mechanisms that are necessary for the distinct coevolutionary pathways to develop between adjacent corridors.
The Role of Plasmacytoid Dendritic Cells in Innate and Adaptive Immune Responses against Alpha Herpes Virus Infections
Authors: Schuster Philipp , Boscheinen Jan Bernardin , Tennert Karin , Schmidt Barbara
Published: March 2011

In 1999, two independent groups identified plasmacytoid dendritic cells (PDC) as major type I interferon- (IFN-) producing cells in the blood. Since then, evidence is accumulating that PDC are a multifunctional cell population effectively coordinating innate and adaptive immune responses. This paper focuses on the role of different immune cells and their interactions in the surveillance of alpha herpes virus infections, summarizes current knowledge on PDC surface receptors and their role in direct cell-cell contacts, and develops a risk factor model for the clinical implications of herpes simplex and varicella zoster virus reactivation. Data from studies involving knockout mice and cell-depletion experiments as well as human studies converge into a “spider web”, in which the direct and indirect crosstalk between many cell populations tightly controls acute, latent, and recurrent alpha herpes virus infections. Notably, cells involved in innate immune regulations appear to shape adaptive immune responses more extensively than previously thought.
Coherent Optical DFT-Spread OFDM
Authors: Wang Fanggang , Wang Xiaodong
Published: March 2011

We consider application of the discrete Fourier transform-spread
orthogonal frequency-division multiplexing (DFT-spread OFDM) technique to high-speed fiber optic communications. The DFT-spread OFDM is a form of single-carrier technique that possesses almost all advantages of the multicarrier OFDM technique (such as high spectral efficiency, flexible bandwidth allocation, low sampling rate, and low-complexity equalization). In particular, we consider the optical DFT-spread OFDM system with polarization division multiplexing (PDM) that employs a tone-by-tone linear minimum mean square error (MMSE) equalizer. We show that such a system offers a much lower peak-to-average power ratio (PAPR) performance as well as better bit error rate (BER) performance compared with the optical
OFDM system that employs amplitude clipping.
Wegener's Granulomatosis: A Rare Cause of Hydronephrosis
Authors: Lillaz Julien , Bernardini Stéphane , Algros Marie-Paule , Bittard Hugues , Kleinclauss François
Published: March 2011

A seventy-one-year-old woman was hospitalized at our institution for a right-sided “renal colic” associated with an infectious background. Alithiasic ureterohydronephrosis was diagnosed by imaging. A urinary diversion was thus performed using a double J endoureteral stent. The etiologic assessment of the hydronephrosis showed the presence of a periureteral mass that caused extrinsic ureteral compression. After surgical excision of the ureteral lesion, the Wegener's granulomatosis diagnosis was established. This report is the clinical description of a case of “atypical” Wegener's granulomatosis revealed by the onset of a ureteral disease mimicking a neoplastic process.
Quantification and Evaluation of the Role of Antielastin Autoantibodies in the Emphysematous Lung
Authors: Low Teck Boon , Greene Catherine M. , O'Neill Shane J. , McElvaney Noel G.
Published: March 2011

Chronic obstructive pulmonary disease (COPD) may be an autoimmune disease. Smoking causes an imbalance of proteases and antiproteases in the lung resulting in the generation of elastin peptides that can potentially act as autoantigens. Similar to COPD, Z alpha-1 antitrypsin deficiency (Z-A1ATD) and cystic fibrosis (CF) are associated with impaired pulmonary antiprotease defences leading to unopposed protease activity. Here, we show that there is a trend towards higher bronchoalveolar lavage fluid (BALF) antielastin antibody levels in COPD and Z-A1ATD and significantly lower levels in CF compared to control BALF; the lower levels in CF are due to the degradation of these antibodies by neutrophil elastase. We also provide evidence that these autoantibodies have the potential to induce T cell proliferation in the emphysematous lung. This study highlights that antielastin antibodies are tissue specific, can be detected at elevated levels in COPD and Z-A1ATD BALF despite their being no differences in their levels in plasma compared to controls, and suggests a therapeutic role for agents targeting these autoantibodies in the lungs.
Characterization of Generators for Multiresolution Analyses with Composite Dilations
Authors: Zhu Yuan , Gao Wenjun , Li Dengfeng
Published: March 2011

This paper introduces multiresolution analyses with composite dilations (AB‐MRAs) and addresses frame multiresolution analyses with composite dilations in the setting
of reducing subspaces of L2(ℝn) (AB‐RMRAs). We prove that an AB‐MRA can induce an AB‐RMRA on a given reducing subspace L2(S) ∨. For a general expansive matrix, we obtain
the characterizations for a scaling function to generate an AB‐RMRA, and the main theorems
generalize the classical results. Finally, some examples are provided to illustrate the general
theory.
Racial Variation in Umbilical Cord Blood Leptin Concentration in Male Babies
Authors: Lai Gabriel Y. , Rohrmann Sabine , Agurs-Collins Tanya , Sutcliffe Catherine G. , Bradwin Gary , Rifai Nader , Bienstock Jessica L. , Platz Elizabeth A.
Published: March 2011

Background: We hypothesize that racial differences in utero contribute to the racial disparity in prostate cancer risk. Leptin is a candidate for evaluating this hypothesis because it influences fetal development and newborn growth.

Methods: We measured leptin concentration by ELISA in venous cord blood collected from 70 African-American and 37 white male full-term babies. We measured sex steroid hormones and insulin-like growth factor (IGF) axis concentrations previously. Separately by race, we calculated the geometric mean leptin concentration and estimated the geometric mean adjusted for birth and placental weights, mother's age and parity, time of day and season of birth, and sex steroid hormone and IGF axis concentrations by linear regression.

Results: Leptin was positively correlated with birth (r = 0.34) and placental (r = 0.25) weights, IGF-1 (r = 0.21), and IGF binding protein-3 (r = 0.29) adjusting for race. Unadjusted geometric mean leptin did not differ (P = 0.92) between African Americans (5,280 pg/mL; 95% CI: 4,322–6,451) and whites (5,187 pg/mL; 95% CI: 3,938–6,832). Adjusted geometric mean leptin was nonstatistically significantly higher (P = 0.15) in African Americans (5,954 pg/mL; 95% CI: 4,725–7,502) than in whites (4,133 pg/mL; 95% CI: 2,890–5,910).

Conclusion: We observed a nonsignificantly higher adjusted cord blood leptin concentration in African-American male babies than in white male babies, although unadjusted levels were similar.

Impact: These findings do not support the hypothesis that leptin level in utero contributes to the racial disparity in prostate cancer risk in adulthood. Cancer Epidemiol Biomarkers Prev; 20(4); 665–71. ©2011 AACR.
Serum Salicylate Levels and Risk of Recurrent Colorectal Adenomas
Authors: Shaukat Aasma , Grau Maria V. , Church Timothy R. , Baxter Gwen , Barry Elizabeth L. , Summers Robert , Sandler Robert S. , Baron John A.
Published: March 2011

Background: Intake of aspirin is associated with reduction in risk of colorectal adenoma and carcinoma. Some plants contain salicylates, and individuals not taking aspirin may have measurable salicylate levels. However, the association between serum salicylate level and recurrence of adenoma in nonusers of aspirin has not been studied.

Methods: We measured serum salicylate levels in participants in a randomized controlled trial with calcium supplementation for the prevention of colorectal adenomas. Generalized linear models were used to assess the association between serum levels and adenoma risk during the follow-up period of the trial.

Results: We did not find an association with recurrence of adenomas or advanced adenomas with serum salicylate levels at year 1 among nonusers of aspirin. There was no effect modification of the chemopreventive effect of calcium supplementation in reducing risk of recurrent adenomas or advanced adenomas.

Conclusions: Among nonusers of ASA, serum salicylate levels are not associated with risk of recurrence of adenomas.

Impact: Serum salicylate levels can be detected in individuals not taking aspirin, but the levels may be too low to confer protection from risk of recurrent adenomas. Cancer Epidemiol Biomarkers Prev; 20(4); 679–82. ©2011 AACR.