bluuebunny/crossref_metadata_2025 huggingface dataset:
Levels of mortality in hens by end of lay on farm and in transit to slaughter in Great Britain
Authors: Weeks C. A. , Brown S. N. , Richards G. J. , Wilkins L. J. , Knowles T. G.
Published: June 2012

The average mortality for end of lay hens dead on arrival (DOA) was 0.27 per cent (median 0.15 per cent) in a survey of 13.3 million hens transported during 2009. A statistical model of the data indicated main risk factors for DOA to be slaughter plant, distance travelled and external air temperature, with longer journeys and low external air temperatures increasing the risk. Other highly significant risk factors (P < 0.001) related to the condition of the birds on farm, where an increased risk of DOA was positively associated with poor feather cover, lower body weight, cumulative mortality of the flock and poor health (indicated by a high proportion of the load rejected at the plant for traumatic injury and disease state). However, the data indicate that by taking risk factors into consideration it is possible to transport hens up to 960 km with low losses in temperate conditions. Mean levels of on‐farm mortality, during the laying period, for a total of 1486 flocks were significantly lower in cages (5.39 per cent) than in barn (8.55 per cent), free‐range (9.52 per cent) or organic flocks (8.68 per cent) according to producer records a median of seven days before depopulation, with considerable variation between flocks in all systems.
Extraction of s-block metals by nano-baskets of calix[4]crown-3
Authors: Mokhtari Bahram , Pourabdollah Kobra
Published: June 2012

Three kinds of nano-baskets including 1,2-alternate and cone conformers of di-ionizable p-tert-butylcalix[4]arene-1,2-crown-3 and the cone conformer of p-tert-butylcalix[4]arene-1,2-thiacrown-3 were synthesized and the competitive solvent extractions of alkali and alkaline earth metal cations were studied. The novelty of this study is including three binding units of the calixarene’s bowl, the crown ether’s ring, and electron-donor ionizable moieties in a unique scaffold, in which their sizes were selected based upon their complexation ability to show equal binding tendency towards the cations. The objective of this work is to assess the extraction efficiency, selectivity, and pH1/2 of such complexes. The results of solvent extraction experiments indicated that these compounds were effective extractants of alkali and alkaline earth metal cations. Their selectivities were greatly influenced by the acidity of the solution and the conformations of the calixcrown. One conformer was highly selective to Na+ and the other to Ba2+ in acidic and basic solutions, respectively.
Highly selective mono-N-benzylation and amidation of amines with alcohols or carboxylic acids using the Ph2PCl/I2/imidazole reagent system
Authors: Nowrouzi Najmeh , Jonaghani Mohammad Zareh
Published: June 2012

Chlorodiphenylphosphine, imidazole, and molecular iodine in refluxing dichloromethane are used for the efficient preparation of amides under mild reaction conditions. This reagent system also shows excellent selectivity for mono-N-alkylation of amines with alcohols. In this system, the resulting phosphorus byproduct (diphenylphosphinic acid) is easily removed by extraction using an aqueous basic solution in the workup processes, which avoids the tedious and time-consuming chromatographic methods.
Studies on the reaction of nitric oxide with α,β-unsaturated hydrazones
Authors: Yang Desuo , Luo Xiaolin , Zhu Haiyun , Guo Yaning , Wu Longmin
Published: June 2012

α,β-Unsaturated arylhydrazones (1) reacted with nitric oxide (NO) in the presence of a trace of oxygen to give α- (2a–2c, 2e, and 2f) or β-nitro (2d and 2g) unsaturated hydrazones in good yield and with high stereoselectivity. The reaction occurs most likely by an electrophilic addition of NO2to the carbon–carbon double bond of 1 at its α- or β-position.
Preparation and application of copper hydroxide (oxide) / multiwalled carbon nanotubes nanocomposite-modified glassy carbon electrode as a nitrite sensor
Authors: Liu Youqin , Tian Xiuying , Yan Yun , Xu Yuehua
Published: June 2012

Copper hydroxide (oxide) / multiwalled carbon nanotubes nanocomposite-modified glassy carbon electrode (Cuhydroxide/oxide/MWCNTs/GCE) was successfully prepared by a novel film plating / cyclic voltammetry (CV) method, which exhibited marked synergistic catalytic effects on the electro-oxidation of NO2–. The preparation process, impedance behavior, and surface morphology of Cuhydroxide/oxide/MWCNTs/GCE were investigated by CV, electrochemical impedance spectroscopy, and scanning electron microscopy (SEM), respectively. The optimum preparation and test conditions for the electrode to have high catalytic activity were acquired. The linear range between the anodic current (Δia, µA) and NO2– concentration (c, mmol L−1) was 1.0 × 10−4 to 14.0 mmol L−1, and the corresponding calibration curve was Δia = −0.1504 + 57.954c (R = 0.9990, n = 32) with a detection limit of 0.03 µmol L−1 (S/N = 3). The Cuhydroxide/oxide/MWCNTs/GCE prepared in the optimal conditions showed good stability, high selectivity, low detection limit, and quick response (<0.2 s) to NO2– in phosphate buffer (pH 5.29) at 0.78 V, which has been successfully applied to the determination of NO2– in pickled vegetables with satisfactory results.
Effect of some surfactants on the chemiluminescent reactions of bis(2,4,6-trichlorophenyl)oxalate and bis(2-nitrophenyl)oxalate with hydrogen peroxide
Authors: Dantoni Patrícia , Rodrigues Ana Clara B. , Matsuda Margareth Mie N. , Coichev Nina
Published: June 2012

The chemiluminescent reactions of bis(2,4,6-trichlorophenyl)oxalate (TCPO) and bis(2-nitrophenyl)oxalate (2-NPO) with hydrogen peroxide in acetonitrile/water micellar systems (anionic, cationic, and non-ionic) and γ-cyclodextrin were studied in the presence of fluoranthene or 9,10-diphenylanthracene, imidazole, and two buffer solutions, HTRIS+/TRIS and H2PO4–/HPO42–. The relative chemiluminenscence (CL) intensity is higher in the presence of the cationic (DDAB, CTAC, DODAC, and OTAC), anionic (SDS), and non-ionic (Tween 80) surfactants. In the presence of some non-ionic surfactants (Brij 35, Brij 76, and Tween 20), the CL intensity was partially quenched compared with the reaction with no surfactant. The sensitivity for hydrogen peroxide determination in the range 0.01 × 10−4 to 1.0 × 10−4 mol L–1, considering the slope of the calibration curves (maximum peak height of CL vs. concentration), improved with the introduction of DDAH, CTAB, and SDS in HTRIS+/TRIS buffer.
Aromatic radical perfluoroalkylation reactions
Authors: Postigo Al
Published: June 2012

This account intends to cover recent literature on radical perfluoroalkylation reactions of aromatic nuclei in organic and aqueous media. Emphasis will be placed on radical aromatic perfluoroalkylation reactions in water or aqueous media, with the aim of exploring aromatic radical reactivity in a benign environment.
Highly diastereoselective Mannich-type reaction of titanium enolate derived from 2′-hydroxypropiophenone
Authors: Deng Guisheng , Mo Honghua , Luo Jing , Zou Jingyuan
Published: June 2012

Mannich-type addition of the titanium enolate derived from 2′-hydroxypropiophenone to N-tosylimines provided the corresponding β-aminoketones in good to excellent yields (60%–90%) and with >99 : <1 anti diastereoselectivity. A model for synthesis of anti β-aminoketone as a predominant isomer based on the titanium enolate has been developed. High anti selectivity is not independent of the electron-donating and electron-withdrawing groups on the phenyl ring of the N-tosylimines. Noteworthy is the observation that the influence of a second Lewis acid on the Mannich-type reaction based on the titanium enolate is opposite to that obtained from other titanium enolates reported. A reasonable mechanism has been proposed to explain the high anti diastereoselectivity and the effect of a second Lewis acid on yield.
Gold cellular networks inside water-soluble sodium alginate sol
Authors: Wei Jishi , Yang Jianmao , Gao Shuyan
Published: June 2012

The present work demonstrates the fabrication of unique gold cellular networks inside water-soluble sodium alginate sol. In conjunction with control experiments, UV–vis spectra and TEM images structurally give a piece of robust evidence that Au(III) and sodium alginate combined with preparation parameters synergically favor the formation of gold cellular networks. From the viewpoint of green chemistry, the cheap and safe reactant sodium alginate and the friendly aqueous medium make the present method possible for applications in large-scale production of metallic cellular networks. Thus, coupled with facile and green creation, the gold cellular networks open new opportunities for noble metal nanostructures, with different morphologies, as biological labels, energy transfer pairs, and other nanoscale electronics.
Decomposition of copper – amino acid complexes by oxalic acid dihydrate
Authors: Liu Yi , Jia Genguang , Ling Xin , Lan Nuo , Zheng Youguang , Li Sai , Zhang Ling , Liu Ling , Zhang Rongli , Xue Yunsheng
Published: June 2012

A facile approach to the synthesis of some side-chain-protected amino acids via oxalic acid dihydrate as the copper sequestering reagent is presented. The copper in the amino acid complex reacted with oxalic acid dihydrate to form insoluble cupric oxalate, with the free amino acid released. Compared with conventional methods, this method is convenient, inexpensive, and environmentally friendly.
SPAN: SPIKE PATTERN ASSOCIATION NEURON FOR LEARNING SPATIO-TEMPORAL SPIKE PATTERNS
Authors: MOHEMMED AMMAR , SCHLIEBS STEFAN , MATSUDA SATOSHI , KASABOV NIKOLA
Published: June 2012

Spiking Neural Networks (SNN) were shown to be suitable tools for the processing of spatio-temporal information. However, due to their inherent complexity, the formulation of efficient supervised learning algorithms for SNN is difficult and remains an important problem in the research area. This article presents SPAN — a spiking neuron that is able to learn associations of arbitrary spike trains in a supervised fashion allowing the processing of spatio-temporal information encoded in the precise timing of spikes. The idea of the proposed algorithm is to transform spike trains during the learning phase into analog signals so that common mathematical operations can be performed on them. Using this conversion, it is possible to apply the well-known Widrow–Hoff rule directly to the transformed spike trains in order to adjust the synaptic weights and to achieve a desired input/output spike behavior of the neuron. In the presented experimental analysis, the proposed learning algorithm is evaluated regarding its learning capabilities, its memory capacity, its robustness to noisy stimuli and its classification performance. Differences and similarities of SPAN regarding two related algorithms, ReSuMe and Chronotron, are discussed.
HARDWARE IMPLEMENTATION OF STOCHASTIC SPIKING NEURAL NETWORKS
Authors: ROSSELLÓ JOSEP L. , CANALS VINCENT , MORRO ANTONI , OLIVER ANTONI
Published: June 2012

Spiking Neural Networks, the last generation of Artificial Neural Networks, are characterized by its bio-inspired nature and by a higher computational capacity with respect to other neural models. In real biological neurons, stochastic processes represent an important mechanism of neural behavior and are responsible of its special arithmetic capabilities. In this work we present a simple hardware implementation of spiking neurons that considers this probabilistic nature. The advantage of the proposed implementation is that it is fully digital and therefore can be massively implemented in Field Programmable Gate Arrays. The high computational capabilities of the proposed model are demonstrated by the study of both feed-forward and recurrent networks that are able to implement high-speed signal filtering and to solve complex systems of linear equations.
MODELING FLUCTUATIONS IN DEFAULT-MODE BRAIN NETWORK USING A SPIKING NEURAL NETWORK
Authors: YAMANISHI TERUYA , LIU JIAN-QIN , NISHIMURA HARUHIKO
Published: June 2012

Recently, numerous attempts have been made to understand the dynamic behavior of complex brain systems using neural network models. The fluctuations in blood-oxygen-level-dependent (BOLD) brain signals at less than 0.1 Hz have been observed by functional magnetic resonance imaging (fMRI) for subjects in a resting state. This phenomenon is referred to as a "default-mode brain network." In this study, we model the default-mode brain network by functionally connecting neural communities composed of spiking neurons in a complex network. Through computational simulations of the model, including transmission delays and complex connectivity, the network dynamics of the neural system and its behavior are discussed. The results show that the power spectrum of the modeled fluctuations in the neuron firing patterns is consistent with the default-mode brain network's BOLD signals when transmission delays, a characteristic property of the brain, have finite values in a given range.
TRANSLATING SOLITONS FOR LAGRANGIAN MEAN CURVATURE FLOW IN COMPLEX EUCLIDEAN PLANE
Authors: CASTRO ILDEFONSO , LERMA ANA M.
Published: June 2012

Using certain solutions of the curve shortening flow, including self-shrinking and self-expanding curves or spirals, we construct and characterize many new examples of translating solitons for mean curvature flow in complex Euclidean plane. They generalize the Joyce, Lee and Tsui ones [Self-similar solutions and translating solitons for Lagrangian mean curvature flow, J. Differential Geom.84 (2010) 127–161] in dimension two. The simplest (non-trivial) example in our family is characterized as the only (non-totally geodesic) Hamiltonian stationary Lagrangian translating soliton for mean curvature flow in complex Euclidean plane.
SCALING ASYMPTOTICS FOR QUANTIZED HAMILTONIAN FLOWS
Authors: PAOLETTI ROBERTO
Published: June 2012

In recent years, the near diagonal asymptotics of the equivariant components of the Szegö kernel of a positive line bundle on a compact symplectic manifold have been studied extensively by many authors. As a natural generalization of this theme, here we consider the local scaling asymptotics of the Toeplitz quantization of a Hamiltonian symplectomorphism, and specifically how they concentrate on the graph of the underlying classical map.
MULTI-OBJECTIVE OPTIMIZATION APPROACHES TO SOFTWARE RELEASE TIME DETERMINATION
Authors: LI XIANG , XIE MIN , NG SZU HUI
Published: June 2012

Optimal release time determination is a typical application of software reliability models. In this decision process, reliability and cost are the two important dimensions that are generally considered. Most existing research formulates this decision process as single-objective optimization problems. Although these formulations can greatly reduce the complexity, they can hardly reflect the nature of the decision process, which is essentially a multi-objective optimization problem. More specifically, maximizing reliability and minimizing cost should be achieved simultaneously. Due to this consideration, in this paper, software release time determination is investigated by various multi-objective optimization approaches, including the trade-off analysis, multi-attribute utility theory, and physical programming approach. Numerical examples are provided for illustrative purpose. The applicability and limitations of different multi-objective optimization approaches are also discussed, which can help management to make a more reasonable decision in practice.
ON THE FINITENESS PROBLEM FOR AUTOMATON (SEMI)GROUPS
Authors: AKHAVI ALI , KLIMANN INES , LOMBARDY SYLVAIN , MAIRESSE JEAN , PICANTIN MATTHIEU
Published: June 2012

This paper addresses a decision problem highlighted by Grigorchuk, Nekrashevich, and Sushchanskiĭ, namely the finiteness problem for automaton (semi)groups. For semigroups, we give an effective sufficient but not necessary condition for finiteness and, for groups, an effective necessary but not sufficient condition. The efficiency of the new criteria is demonstrated by testing all Mealy automata with small stateset and alphabet. Finally, for groups, we provide a necessary and sufficient condition that does not directly lead to a decision procedure.
LIMITS OF THE QUANTUM SO(3) REPRESENTATIONS FOR THE ONE-HOLED TORUS
Authors: SANTHAROUBANE RAMANUJAN
Published: June 2012

For N ≥ 2, we study a certain sequence [Formula: see text] of N-dimensional representations of the mapping class group of the one-holed torus arising from SO(3)-TQFT, and show that the conjecture of Andersen, Masbaum, and Ueno [Topological quantum field theory and the Nielsen–Thurston classification of M(0,4), Math. Proc. Cambridge Philos Soc.141 (2006) 477–488] holds for these representations. This is done by proving that, in a certain basis and up to a rescaling, the matrices of these representations converge as p tends to infinity. Moreover, the limits describe the action of SL2(ℤ) on the space of homogeneous polynomials of two variables of total degree N - 1.
INSTANTON REPRESENTATION OF PLEBANSKI GRAVITY: APPLICATION TO GRAVITONS ABOUT de SITTER SPACETIME
Authors: ITA EYO EYO
Published: June 2012

Using the instanton representation method, we re-construct graviton solutions about de Sitter spacetime. We have used this example as a testing arena to expose the internal structure of the method and to establish that it works for known solutions. This paper is a precursor for its application to the construction of new General Relativity solutions in future work.
ELECTRO-MECHANICAL DELAY IN HILL-TYPE MUSCLE MODELS
Authors: MÖRL FALK , SIEBERT TOBIAS , SCHMITT SYN , BLICKHAN REINHARD , GÜNTHER MICHAEL
Published: June 2012

In this study, we investigated to which extent Hill-type muscle models can explain the electro-mechanical delay (EMD). The EMD is a phenomenon that has been well examined in muscle experiments. The EMD is the time lag between a change in muscle stimulation and the subsequent measurable change in muscle force. A variety of processes as, e.g., signal conduction and interaction of contractile and elastic muscle structures contribute to the EMD. The relative contributions of the particular processes have not been fully unveiled so far. Thereto, we simulated isometric muscle contractions using two Hill-type muscle models. Their parameters were extracted from experiments on the cat soleus muscle. In agreement with literature data, predicted EMD values depend on muscle-tendon complex (MTC) length and increase when reducing MTC lengths. The highest EMD values (28 and 27 ms) occur at the lowest MTC length examined (78% of optimal length). Above optimal MTC length, we find EMD saturation (2 ms) in one model. In the other model, the EMD slightly re-increases up to 9 ms at the highest length examined (113% of optimal length). The EMD values predicted by the two models were then compared to EMD values found in the same experiments from which the muscle parameters were extracted. At optimal MTC length, the EMD values, mapping ion release and visco-elastic interactions, predicted by both models (3.5 and 5.5 ms) just partly account for the measured value (15.8 ms). The biggest share (about 9 ms) of the remaining 11 ms can be attributed to signal conduction along the nerve and on the muscle surface. Further potential sources of delayed force generation are discussed.
Synthesis of di-pyropheophorbide-a-platinum(II) complex and the in vitro cytotoxicity against TC-1 tumor cells
Authors: Battogtokh Gantumur , Liu Hai-Bo , Bae Su-Mi , Chaturvedi Pankaj Kumar , Kim Yong-Wan , Kim In-Wook , Ahn Woong Shick
Published: June 2012

This report focuses on the conjugation of a chemotherapeutic drug and photodynamic therapy (PDT) agent with the intention of obtaining an optimal anticancer agent for use in combination cancer treatment. We have used pyropheophorbide-a (PPa) as a PDT agent, which was linked with ethylenediamine using carbodimide/N-hydroxysuccinicimide coupling reagents to obtain a resulting reactive amine group. Next, the free amine-bearing PPa and potassium tetrachloroplatinate (K2PtCl4) were reacted in aqueous solution to obtain PPa-cisplatin complex. Subsequently, the PPa-based platinum complex was characterized through several methods including NMR spectroscopy, mass spectrometer and UV absorption spectroscopy and its in vitro cytotoxicity and cellular uptake were evaluated on the TC-1 cancer cell line. The results indicated that the conjugate has a greater cytotoxic effect in the dark than cisplatin, even though its phototoxic effect was slightly lower than that of free photosensitizer; in addition, the cellular uptake of complex at 0.125 and 0.25 μM was higher than that of free photosensitizer.
NON-VANISHING OF DIRICHLET L-FUNCTIONS AT THE CENTRAL POINT
Authors: BUI H. M.
Published: June 2012

Let χ be a primitive Dirichlet character modulo q and L(s, χ) be the Dirichlet L-function associated to χ. Using a new two-piece mollifier we show that L(½, χ) ≠ 0 for at least 34% of the characters in the family.
WEIGHTED SUMS WITH TWO PARAMETERS OF MULTIPLE ZETA VALUES AND THEIR FORMULAS
Authors: MACHIDE TOMOYA
Published: June 2012

A typical formula of multiple zeta values is the sum formula which expresses a Riemann zeta value as a sum of all multiple zeta values of fixed weight and depth. Recently weighted sum formulas, which are weighted analogues of the sum formula, have been studied by many people. In this paper, we give two formulas of weighted sums with two parameters of multiple zeta values. As applications of the formulas, we find some linear combinations of multiple zeta values which can be expressed as polynomials of usual zeta values with coefficients in the rational polynomial ring generated by the two parameters, and obtain some identities for weighted sums of multiple zeta values.
REPRESENTATION OF A 2-POWER AS SUM OF k 2-POWERS: THE ASYMPTOTIC BEHAVIOR
Authors: MOLTENI G.
Published: June 2012

A k-representation of an integer ℓ is a representation of ℓ as sum of k powers of 2, where representations differing by the order are considered as distinct. Let [Formula: see text] be the maximum number of such representations for integers ℓ whose binary representation has exactly σ non-zero digits. [Formula: see text] can be recovered from [Formula: see text] via an explicit formula, thus in some sense [Formula: see text] is the fundamental object. In this paper we prove that [Formula: see text] tends to a computable limit as k diverges. This result improves previous bounds which were obtained with purely combinatorial tools.
DEDEKIND SUMS WITH SMALL DENOMINATORS
Authors: GIRSTMAIR KURT
Published: June 2012

Let (m, n) = 1 and S(m/n) = 12s(m/n), where s(m/n) is the usual Dedekind sum. Then [Formula: see text]. Let q ≥ 1 be a divisor of n. We give a necessary and sufficient condition for [Formula: see text] and, thereby, generalize a result of Rademacher that concerns the case q = 1. Further, we study the structure of possible denominators q of S(m/n). Finally, we show that for certain quadratic irrationals of odd period length l the convergents sk/tk, k ≡ l - 1 ( mod 2l), yield stationary values of S(sk/tk). This means that, for large values of k, the denominators q of these Dedekind sums are very small compared with tk.
THE DYNAMICAL MODELS OF ACTIVATED SLUDGE SYSTEM: STOCHASTIC CELLULAR AUTOMATON AND DIFFERENTIAL EQUATIONS
Authors: LIAO JINBAO , LU HUI , LI ZHENQING , MENG XINZHU , ENGLUND GÖRAN
Published: June 2012

A stochastic cellular automaton (CA) model for activated sludge system (ASS) is formulated by a series of transition functions upon realistic treatment processes, and it is tested by comparing with ordinary differential equations (ODEs) of ASS. CA system performed by empirical parameters can reflect the characteristics of fluctuation, complexity and strong non-linearity of ASS. The results show that the predictions of CA are approximately similar to the dynamical behaviors of ODEs. Based on the extreme experimental system with complete cell recycle in model validation, the dynamics of biomass and substrate are predicted accurately by CA, but the large errors exist in ODEs except for integrating more spatially complicated factors. This is due to that the strong mechanical stress from spatial crowding effect is ignored in ODEs, while CA system as a spatially explicit model takes account of local interactions. Despite its extremely simple structure, CA still can capture the essence of ASS better than ODEs, thus it would be very useful in predicting long-term dynamics in other similar systems.
ELECTROCHEMICAL PROPERTY OF LiMn2O4 IN OVER-DISCHARGED CONDITIONS
Authors: FENG JINKUI , SONG BOHANG , LAI MAN ON , LU LI , ZENG XIANTING , HUANG ZHAOHONG
Published: June 2012

This work studies LiMn 2 O 4 in an over-discharged condition. Electrochemical measurement shows that the LiMn 2 O 4 electrode undergoes an irreversible electrochemical reduction process where its structure is permanently destroyed during over-discharge. Although LiMn 2 O 4 shows a poor over-discharge durance with a reduction starting at 2.5 V vs. Li/Li+ , the galvanostatic test indicates that LiMn 2 O 4 can be considered to be used as a high capacity anode material for lithium ion batteries with an initial charge capacity of 814 mAh ⋅ g-1 and 452 mAh ⋅ g-1 at the 100th cycle.
MILD SYNTHESIS ROUTE TO NANOSTRUCTURED α-MnO2 AS ELECTRODE MATERIALS FOR ELECTROCHEMICAL ENERGY STORAGE
Authors: ZHANG YUANJIAN , XUE DONGFENG
Published: June 2012

α- MnO 2 electrode materials with sphere-, rod- and flower-like nanostructures were for the first time fabricated by a redox reaction between KMnO4 and NaHSO3 in chemical bath. Crystal structure and morphology of the as-crystallized samples were characterized by X-ray diffraction and scanning electron microscopy. The influence of reaction temperature and H+ concentration on both morphology and crystalline nature was investigated. Their electrochemical behaviors were investigated by cycling voltammetry and galvanostatic charge/discharge measurements in a three-electrode glass cell. Depending upon different synthesis conditions of α- MnO 2 electrodes, their specific capacitance values varied in the range of 43 to 197 F g-1 at the current density of 1 A g-1. Moreover, their specific capacitance values decrease with increasing crystallinity and particle size. In this work, we conclude that the energy storage mechanism is closely related to the particle aggregation state of electrode materials.
NONCOMMUTATIVITY, OPEN STRINGS AND LOOSE ENDS
Authors: SCHUPP PETER
Published: June 2012

We give a brief overview of work by and in collaboration with Julius Wess in his noncommutative era.
ON THE ALL ORDER SOLUTIONS OF SEIBERG-WITTEN MAP FOR NONCOMMUTATIVE GAUGE THEORIES
Authors: ÜLKER KAYHAN
Published: June 2012

We review the recursive solutions of the Seiberg–Witten map to all orders in θ for gauge, matter and ghost fields. We also present the general structure of the homogeneous solutions of the defining equations. Moreover, we show that the contribution of the first order homogeneous solution to the second order can be written recursively similar to inhomogeneous solutions.
Determination of Ratio of Diamagnetic Anisotropy of a Biaxial Crystal by X-ray Diffraction Measurement
Authors: Guangjie Song , Matsumoto Kenji , Fujita Keiji , Kimura Fumiko , Kimura Tsunehisa
Published: June 2012

The ratio of diamagnetic anisotropy of a biaxial crystal (cellobiose: monoclinic, space group P21) was determined using two X-ray fiber diffraction patterns that were obtained from its microcrystalline powder oriented in static and rotating magnetic fields. We first determined the directions of the magnetic axes with respect to the crystallographic axes. We found that χ3 is parallel to the b
*-axis, and the χ1-axis forms angles of 67.9 and 22.8° with respect to the a
*- and c
*-axes, respectively. Using the analysis method proposed recently, azimuthal half widths of the X-ray diffraction spots for (h
k
l) planes of the oriented samples were plotted as a function of sin
2Φ, where Φ is an angle that characterizes the direction of the reciprocal vector of the (h
k
l) plane in the χ1χ2χ3 coordinates, with χ1, χ2, and χ3 being the principal axes of the magnetic susceptibility tensor. The half width linearly depended on sin
2Φ as predicted by the proposed method. From the values of the slope and intercept of the plot, the ratio of the diamagnetic anisotropy, r
χ=(χ2-χ3)/(χ1-χ2) was determined, where χ1>χ2>χ3. We estimated that r
χ=1.4–1.7.
Performance Analysis of Reconfigurations in Adaptive Real-Time Streaming Applications
Authors: Zhu Jun , Sander Ingo , Jantsch Axel
Published: June 2012

We propose a performance analysis framework for adaptive real-time synchronous data flow streaming applications on runtime reconfigurable FPGAs. As the main contribution, we present a constraint based approach to capture both streaming application execution semantics and the varying design concerns during reconfigurations. With our event models constructed as cumulative functions on data streams, we exploit a novel compile-time analysis framework based on iterative timing phases. Finally, we implement our framework on a public domain constraint solver, and illustrate its capabilities in the analysis of design trade-offs due to reconfigurations with experiments.
Balancing Programmability and Silicon Efficiency of Heterogeneous Multicore Architectures
Authors: Terechko Andrei , Hoogerbrugge Jan , Alkadi Ghiath , Guntur Surendra , Lahiri Anirban , Duranton Marc , Wüst Clemens , Christie Phillip , Nackaerts Axel , Kumar Aatish
Published: June 2012

Multicore architectures provide scalable performance with a lower hardware design effort than single core processors. Our article presents a design methodology and an embedded multicore architecture, focusing on reducing the software design complexity and boosting the performance density. First, we analyze characteristics of the Task-Level Parallelism in modern multimedia workloads. These characteristics are used to formulate requirements for the programming model. Then we translate the programming model requirements to an architecture specification, including a novel low-complexity implementation of cache coherence and a hardware synchronization unit. Our evaluation demonstrates that the novel coherence mechanism substantially simplifies hardware design, while reducing the performance by less than 18% relative to a complex snooping technique. Compared to a single processor core, the multicores have already proven to be more area- and energy-efficient. However, the multicore architectures in embedded systems still compete with highly efficient function-specific hardware accelerators. In this article we identify five architectural methods to boost performance density of multicores; microarchitectural downscaling, asymmetric multicore architectures, multithreading, generic accelerators, and conjoining. Then, we present a novel methodology to explore multicore design spaces, including the architectural methods improving the performance density. The methodology is based on a complex formula computing performances of heterogeneous multicore systems. Using this design space exploration methodology for HD and QuadHD H.264 video decoding, we estimate that the required areas of multicores in CMOS 45 nm are 2.5 mm
2
and 8.6 mm
2
, respectively. These results suggest that heterogeneous multicores are cost-effective for embedded applications and can provide a good programmability support.
FlashLight
Authors: Kim Jaegeuk , Shim Hyotaek , Park Seon-Yeong , Maeng Seungryoul , Kim Jin-Soo
Published: June 2012

A very promising approach for using NAND flash memory as a storage medium is a flash file system. In order to design a higher-performance flash file system, two issues should be considered carefully. One issue is the design of an efficient index structure that contains the locations of both files and data in the flash memory. For large-capacity storage, the index structure must be stored in the flash memory to realize low memory consumption; however, this may degrade the system performance. The other issue is the design of a novel garbage collection (GC) scheme that reclaims obsolete pages. This scheme can induce considerable additional read and write operations while identifying and migrating valid pages. In this article, we present a novel flash file system that has the following features: (
i
) a lightweight index structure that introduces the
hybrid indexing scheme
and
intra-inode index logging
, and (
ii
) an efficient GC scheme that adopts a dirty list with an on-demand GC approach as well as fine-grained data separation and
erase-unit data allocation
. We implemented FlashLight in a Linux OS with kernel version 2.6.21 on an embedded device. The experimental results obtained using several benchmark programs confirm that FlashLight improves the performance by up to 27.4% over UBIFS by alleviating index management and GC overheads by up to 33.8%.
Computer-Aided Recoding to Create Structured and Analyzable System Models
Authors: Chandraiah Pramod , Dömer Rainer
Published: June 2012

In embedded system design, the quality of the input model has a direct bearing on the effectiveness of the system exploration and synthesis tools. Given a well-written system model, tools today are effective in generating working implementations. However, readily available C reference code is not conducive for immediate system synthesis as it lacks needed features for automatic analysis and synthesis. Among others, the lack of proper structure and the presence of intractable pointers in the reference code are factors that seriously hamper the effectiveness of system design tools. To overcome these deficiencies, we aim to automate the conversion of flat C code into a well-structured system model by applying automated source code transformations. We present a set of computer-aided
recoding
operations that enable the system designer to mitigate pointer problems and quickly create the necessary structural hierarchy so that the design model becomes easily analyzable and synthesizable. Utilizing the designer’s knowledge, our interactive recoding transformations aid the designer in efficiently creating well-structured system models for rapid design space exploration and successful synthesis. Our estimated and measured experimental results show significant productivity gains through a substantial reduction of the model creation time.
Exploring and Predicting the Effects of Microarchitectural Parameters and Compiler Optimizations on Performance and Energy
Authors: Dubach Christophe , Jones Timothy M. , O'Boyle Michael F. P.
Published: June 2012

Embedded processor performance is dependent on both the underlying architecture and the compiler optimizations applied. However, designing both simultaneously is extremely difficult to achieve due to the time constraints designers must work under. Therefore, current methodology involves designing compiler and architecture in isolation, leading to suboptimal performance of the final product.

This article develops a novel approach to this
codesign
space problem. For our specific design space, we demonstrate that we can automatically predict the performance that an optimizing compiler would achieve without actually tuning it for any of the microarchitecture configurations considered. Once trained, a single run of the program compiled with the standard optimization setting is enough to make a prediction on the new microarchitecture with just a 3.2% error rate on average. This allows the designer to accurately choose an architectural configuration with knowledge of how an optimizing compiler will perform on it. We use this to find the best optimizing compiler/architectural configuration in our codesign space and demonstrate that it achieves an average 19% performance improvement and energy savings of 16% compared to the baseline, nearly doubling the energy-efficiency measured as the energy-delay-squared product (EDD).
Involvement of γ-aminobutyric acid transporter 2 in the hepatic uptake of taurine in rats
Authors: Ikeda Saori , Tachikawa Masanori , Akanuma Shin-ichi , Fujinawa Jun , Hosoya Ken-ichi
Published: June 2012

Taurine is essential for the hepatic synthesis of bile salts and, although taurine is synthesized mainly in pericentral hepatocytes, taurine and taurine-conjugated bile acids are abundant in periportal hepatocytes. One possible explanation for this discrepancy is that the active supply of taurine to hepatocytes from the blood stream is a key regulatory factor. The purpose of the present study is to investigate and identify the transporter responsible for taurine uptake by periportal hepatocytes. An in vivo bolus injection of [3H]taurine into the rat portal vein demonstrated that 25% of the injected [3H]taurine was taken up by the liver on a single pass. The in vivo uptake was significantly inhibited by GABA, taurine, β-alanine, and nipecotic acid, a GABA transporter (GAT) inhibitor, each at a concentration of 10 mM. The characteristics of Na+- and Cl−-dependent [3H]taurine uptake by freshly isolated rat hepatocytes were consistent with those of GAT2 (solute carrier SLC6A13). Indeed, the Kmvalue of the saturable uptake (594 μM) was close to that of mouse SLC6A13-mediated taurine transport. Although GABA, taurine, and β-alanine inhibited the [3H]taurine uptake by > 50%, each at a concentration of 10 mM, GABA caused a marked inhibition with an IC50value of 95 μM. The [3H]taurine uptake exhibited a significant reduction when the GAT2 gene was silenced. Immunohistochemical analysis showed that GAT2 was localized on the sinusoidal membrane of the hepatocytes predominantly in the periportal region. These results suggest that GAT2 is responsible for taurine transport from the circulating blood to hepatocytes predominantly in the periportal region.
Cytosolic sulfotransferase 2B1b promotes hepatocyte proliferation gene expression in vivo and in vitro
Authors: Zhang Xin , Bai Qianming , Xu Leyuan , Kakiyama Genta , Pandak William M. , Zhang Zhigang , Ren Shunlin
Published: June 2012

Cytosolic sulfotransferase 2B1b (SULT2B1b) catalyzes the sulfation of 3β-hydroxysteroids and functions as a selective cholesterol and oxysterol sulfotransferase. Activation of liver X receptors (LXRs) by oxysterols has been known to be an antiproliferative factor. Overexpression of SULT2B1b impairs LXR's response to oxysterols, by which it regulates lipid metabolism. The aim of this study was to investigate in vivo and in vitro effects of SULT2B1b on liver proliferation and the underlying mechanisms. Primary rat hepatocytes and C57BL/6 mice were infected with adenovirus encoding SULT2B1b. Liver proliferation was determined by measuring the proliferating cell nuclear antigen (PCNA) immunostaining labeling index. The correlation between SULT2B1b and PCNA expression in mouse liver tissues was determined by double immunofluorescence. Gene expressions were evaluated by quantitative real-time PCR and Western blot analysis. SULT2B1b overexpression in mouse liver tissues increased PCNA-positive cells in a dose- and time-dependent manner. The increased expression of PCNA in mouse liver tissues was only observed in the SULT2B1b transgenic cells. Small interference RNA SULT2B1b significantly inhibited cell cycle regulatory gene expressions in primary rat hepatocytes. LXR activation by T0901317 effectively suppressed SULT2B1b-induced gene expression in vivo and in vitro. SULT2B1b may promote hepatocyte proliferation by inactivating oxysterol/LXR signaling.
Postprandial inhibition of gastric ghrelin secretion by long-chain fatty acid through GPR120 in isolated gastric ghrelin cells and mice
Authors: Lu Xinping , Zhao Xilin , Feng Jianying , Liou Alice P. , Anthony Shari , Pechhold Susanne , Sun Yuxiang , Lu Huiyan , Wank Stephen
Published: June 2012

Ghrelin is a gastric peptide hormone that controls appetite and energy homeostasis. Plasma ghrelin levels rise before a meal and fall quickly thereafter. Elucidation of the regulation of ghrelin secretion has been hampered by the difficulty of directly interrogating ghrelin cells diffusely scattered within the complex gastric mucosa. Therefore, we generated transgenic mice with ghrelin cell expression of green fluorescent protein (GFP) to enable characterization of ghrelin secretion in a pure population of isolated gastric ghrelin-expressing GFP (Ghr-GFP) cells. Using quantitative RT-PCR and immunofluorescence staining, we detected a high level of expression of the long-chain fatty acid (LCFA) receptor GPR120, while the other LCFA receptor, GPR40, was undetectable. In short-term-cultured pure Ghr-GFP cells, the LCFAs docosadienoic acid, linolenic acid, and palmitoleic acid significantly suppressed ghrelin secretion. The physiological mechanism of LCFA inhibition on ghrelin secretion was studied in mice. Serum ghrelin levels were transiently suppressed after gastric gavage of LCFA-rich lipid in mice with pylorus ligation, indicating that the ghrelin cell may directly sense increased gastric LCFA derived from ingested intraluminal lipids. Meal-induced increase in gastric mucosal LCFA was assessed by measuring the transcripts of markers for tissue uptake of LCFA, lipoprotein lipase (LPL), fatty acid translocase (CD36), glycosylphosphatidylinositol-anchored HDL-binding protein 1, and nuclear fatty acid receptor peroxisome proliferator-activated receptor-γ. Quantitative RT-PCR studies indicate significantly increased mRNA levels of lipoprotein lipase, glycosylphosphatidylinositol-anchored HDL-binding protein 1, and peroxisome proliferator-activated receptor-γ in postprandial gastric mucosa. These results suggest that meal-related increases in gastric mucosal LCFA interact with GPR120 on ghrelin cells to inhibit ghrelin secretion.
Exercise training and muscle microvascular oxygenation: functional role of nitric oxide
Authors: Hirai Daniel M. , Copp Steven W. , Ferguson Scott K. , Holdsworth Clark T. , McCullough Danielle J. , Behnke Bradley J. , Musch Timothy I. , Poole David C.
Published: June 2012

Exercise training induces multiple adaptations within skeletal muscle that may improve local O2delivery-utilization matching (i.e., Po2mv). We tested the hypothesis that increased nitric oxide (NO) function is intrinsic to improved muscle Po2mv kinetics from rest to contractions after exercise training. Healthy young Sprague-Dawley rats were assigned to sedentary ( n = 18) or progressive treadmill exercise training ( n = 10; 5 days/wk, 6–8 wk, final workload of 60 min/day at 35 m/min, −14% grade) groups. Po2mv was measured via phosphorescence quenching in the spinotrapezius muscle at rest and during 1-Hz twitch contractions under control (Krebs-Henseleit solution), sodium nitroprusside (SNP, NO donor; 300 μM), and NG-nitro-l-arginine methyl ester (l-NAME, nonspecific NO synthase blockade; 1.5 mM) superfusion conditions. Exercise-trained rats had greater peak oxygen uptake (V̇o2peak) than their sedentary counterparts (81 ± 1 vs. 72 ± 2 ml·kg−1·min−1, respectively; P < 0.05). Exercise-trained rats had significantly slower Po2mv fall throughout contractions (τ1; time constant for the first component) during control (sedentary: 8.1 ± 0.6; trained: 15.2 ± 2.8 s). Compared with control, SNP slowed τ1to a greater extent in sedentary rats (sedentary: 38.7 ± 5.6; trained: 26.8 ± 4.1 s; P > 0.05) whereas l-NAME abolished the differences in τ1between sedentary and trained rats (sedentary: 12.0 ± 1.7; trained: 11.2 ± 1.4 s; P < 0.05). Our results indicate that endurance exercise training leads to greater muscle microvascular oxygenation across the metabolic transient following the onset of contractions (i.e., slower Po2mv kinetics) partly via increased NO-mediated function, which likely constitutes an important mechanism for training-induced metabolic adaptations.
Evidence that the contraction-induced rapid hyperemia in rabbit masseter muscle is based on a mechanosensitive mechanism, not shared by cutaneous vascular beds
Authors: Turturici Marco , Mohammed Mazher , Roatta Silvestro
Published: June 2012

Several mechanisms have been hypothesized to contribute to the rapid hyperemia at the onset of exercise. The aim of the present study was to investigate the role played by the mechanosensitivity of the vascular network. In 12 anesthetized rabbits blood flow was recorded from the exclusively muscular masseteric artery in response to brief spontaneous contractions (BSC) of the masseter muscle, artery occlusion (AO), muscle compression (MC), and muscle stretch (MS). Activation of masseter muscle was monitored by electromyography (EMG). Responses to AO were also recorded from the mostly cutaneous facial and the central ear arteries. Five animals were also tested in the awake condition. The hyperemic response to BSC (peak amplitude of 394 ± 82%; time to peak of 1.8 ± 0.8 s) developed with a latency of 300–400 ms from the beginning of the EMG burst and 200–300 ms from the contraction-induced transient flow reduction. This response was neither different from the response to AO (peak amplitude = 426 ± 158%), MC, and MS ( P = 0.23), nor from the BSC response in the awake condition. Compared with the masseteric artery, the response to AO was markedly smaller both in the facial (83 ± 18%,) and in the central ear artery (68 ± 20%) ( P < 0.01). In conclusion, the rapid contraction-induced hyperemia can be replicated by a variety of stimuli affecting transmural pressure in muscle blood vessels and is thus compatible with the Bayliss effect. This prominent mechanosensitivity appears to be a characteristic of muscle and not cutaneous vascular beds.
Circadian disruption alters mouse lung clock gene expression and lung mechanics
Authors: Hadden Hélène , Soldin Steven J. , Massaro Donald
Published: June 2012

Most aspects of human physiology and behavior exhibit 24-h rhythms driven by a master circadian clock in the brain, which synchronizes peripheral clocks. Lung function and ventilation are subject to circadian regulation and exhibit circadian oscillations. Sleep disruption, which causes circadian disruption, is common in those with chronic lung disease, and in the general population; however, little is known about the effect on the lung of circadian disruption. We tested the hypothesis circadian disruption alters expression of clock genes in the lung and that this is associated with altered lung mechanics. Female and male mice were maintained on a 12:12-h light/dark cycle (control) or exposed for 4 wk to a shifting light regimen mimicking chronic jet lag (CJL). Airway resistance (Rn), tissue damping (G), and tissue elastance (H) did not differ between control and CJL females. Rn at positive end-expiratory pressure (PEEP) of 2 and 3 cmH2O was lower in CJL males compared with controls. G, H, and G/H did not differ between CJL and control males. Among CJL females, expression of clock genes, Bmal1 and Rev-erb alpha, was decreased; expression of their repressors, Per2 and Cry 2, was increased. Among CJL males, expression of Clock was decreased; Per 2 and Rev-erb alpha expression was increased. We conclude circadian disruption alters lung mechanics and clock gene expression and does so in a sexually dimorphic manner.