bluuebunny/crossref_metadata_2025 huggingface dataset:
Qualitative response of interaction networks: application to the validation of biological models
Authors: Siegel Anne , Guziolowski Carito , Veber Philippe , Radulescu Ovidiu , Le Borgne Michel
Published: August 2008

We advocate the use of qualitative models for the analysis of shift equilibria in large biological systems. We present a mathematical method, allowing qualitative predictions to be made of the behaviour of a biological system. These predictions are not dependent on specific values of the kinetic constants. We show how these methods can be used to improve understanding of a complex regulatory system. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spontaneous particle creation within the external field approximation of QED
Authors: Szpak Nikodem
Published: August 2008

It is expected that strong electromagnetic fields in QED may lead to destabilization of the vacuum, its decay and spontaneous production of an electron‐positron pair if the strength of the electric field exceeds some threshold. We study the problem within an external field approximation of QED in presence of time‐dependent external fields and define the spontaneous particle creation via the adiabatic limit. We consider some model fields, which we solve analytically or numerically, in order to explain the subtlety of the effect and to recognize problems appearing in its proof. We conclude by characterizing when the effect can exist in a stable way and when it becomes unstable w.r.t. small perturbations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Developments in matching and scaling algorithms
Authors: Duff Iain S.
Published: August 2008

We look at some recent work on scaling and matching algorithms. We show how these algorithms can be used as a preprocessor for direct methods for solving symmetric indefinite systems. We also discuss current work towards developing implementations for parallel machines. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Toward fast and accurate methods for dose calculation in radiotherapy
Authors: Frank Martin , Hensel Hartmut , Klar Axel
Published: August 2008

This paper represents a first step toward a moment method for dose calculations in radiotherapy. Starting from a deterministic transport model, a new macroscopic model is derived having two goals in mind: lower computation times on the one hand, high accuracy and model inherent incorporation of tissue inhomogeneities on the other hand. While being fast, the second property is lost in the often used pencil beam models. Some numerical results are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carleman estimate for parabolic equation with memory effects and exact controllability
Authors: Kumarasamy Sakthivel
Published: August 2008

A nonlinear parabolic problem with memory effect is considered. We first establish a Carleman type estimate for a linear problem which is the adjoint of a suitable linearization of the nonlinear problem. As a consequence of this estimate we obtain an observability estimate. Then we establish the exact controllability of the linearized system with distributed control over a subdomain. Finally, we arrive at the controllability of the nonlinear system via a classical fixed point theorem. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical modelling of turbulent flow over rough walls
Authors: Louda Petr , Příhoda Jaromír , Kozel Karel
Published: August 2008

The numerical simulation of turbulent flow over rough walls was carried out for various types of roughness. The mathematical model was based on the Reynolds averaged Navier‐Stokes equations for incompressible flow. The two‐equation SST and oneequation Spalart‐Allmaras turbulence models were used. Boundary conditions on rough walls were prescribed directly on the wall using the SST model modified to account for wall roughness by Hellsten and Laine (1997) and the SA model modified by Aupoix and Spalart (2003). Turbulence models were tested for the constant pressure turbulent boundary layer on the rough wall formed by commercial abrasive paper and by tightly packed spheres. The effect of wall roughness on the decelerated flow over a smoothly contoured ramp with flow separation was investigated. Obtained results were compared with experimental data. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
How to discretize the Total Variation of an image?
Authors: Moisan Lionel
Published: August 2008

Because they are based on finite differences, usual discretizations of the Total Variation lead to aliased images. We propose a new discretization called spectral total variation that agrees with Shannon sampling principles and produces images that can be exactly interpolated. The quality improvement is illustrated experimentally in the case of image deblurring. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of a Joule–heating model related to resistance welding
Authors: González Montesinos María Teresa , Ortegón Gallego Francisco
Published: August 2008

The purpose of this work is to establish the existence of capacity solutions to the thermistor problem under certain weak assumptions on data. Also, some numerical results are shown. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and characterization of sulfonated block copolymers by atom transfer radical polymerization
Authors: Baek Kyung‐Youl
Published: August 2008

Well‐defined sulfonated polystyrene and block copolymers with n‐butyl acrylate (nBA) were synthesized by CuBr catalyzed living radical polymerization. Neopentyl p‐styrene sulfonate (NSS) was polymerized with ethyl‐2‐bromopropionate initiator and CuBr catalyst with N,N,N′,N′‐pentamethylethyleneamine to give poly(NSS) (PNSS) with a narrow molecular weight distribution (MWD < 1.12). PNSS was then acidified by thermolysis resulting in a polystyrene backbone with 100% sulfonic acid groups. Random copolymers of NSS and styrene with various composition ratios were also synthesized by copolymerization of NSS and styrene with different feed ratios (MWD < 1.11). Well defined block copolymers with nBA were synthesized by sequential polymerization of NSS from a poly(n‐butyl acrylate) (PnBA) precursor using CuBr catalyzed living radical polymerization (MWD < 1.29). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5991–5998, 2008
9‐Bromoanthracene photodimers as initiators in controlled radical polymerization: Silane radical atom abstraction coupled with nitroxide mediated polymerization
Authors: Thakur Sona , Smith Jenell R. , Tillman Eric S. , Cohen Nicole A. , Contrella Nathan D.
Published: August 2008

Slow initiation relative to propagation has previously prevented photodimers of 9‐bromoanthracene or 9‐chloroanthracene, formed by [4 + 4] photocyclization reactions of the analogous 9‐haloanthracene, from being viable initiators in atom transfer radical polymerization (ATRP) reactions. The resulting polymers were found to possess high polydispersity index (PDI) values, much higher than expected number average molecular weight (Mn) values, with the reaction displaying a nonlinear relationship between monomer conversion and Mn. We report here the use of silane radical atom abstraction (SRAA) to create initiating bridgehead radicals in the presence of 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) to mediate the polymerization. When using SRAA coupled with nitroxide mediated polymerization, a dramatic decrease in PDI values was observed compared with analogous ATRP reactions, with Mn values much closer to those anticipated based on monomer‐to‐initiator ratios. Analysis using UV‐Vis spectroscopy indicated only partial anthracene labeling (∼ 25%) on the polymers, consistent with thermolysis of the anthracene photodimer coupled with competition between initiation from the bridgehead photodimer radical and silane‐based radical. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6016–6022, 2008
A hybrid‐type, chiral π‐conjugated polymer wrapped with polyhedral oligomeric silsesquioxanes
Authors: Miyake Junpei , Chujo Yoshiki
Published: August 2008

A novel hybrid‐type chiral binaphthyl‐based polyarylene derivative with polyhedral oligomeric silsesquioxanes (POSS) units 2a was prepared by Suzuki–Miyaura coupling polymerization from a chiral (R)‐6,6′‐dibromo‐2,2′‐diPOSS‐substituted 1,1′‐binaphthyl derivative 1a and p‐biphenylene diboronic acid. As a reference, a binaphthyl‐based polyarylene derivative without POSS unit 2b was also prepared. The obtained polymers were studied with thermogravimetric analysis, optical rotations, circular dichroism (CD), ultraviolet‐visible, and photoluminescence (PL) spectra. Gel permeation chromatography measurements of 2a and 2b showed that their number‐average molecular weights were 13,300 and 16,500, respectively. The thermal stability of POSS‐modified polymer 2a (temperature of 10% weight loss; T10 = 380 °C) was extremely high compared with that of polymer without POSS unit 2b (T10 = 335 °C) due to the siliceous bulky POSS segments on the side chains. The specific optical rotation [α]D was −66.7° (c 0.06, CHCl3) for 2a and −62.3° (c 0.06, CHCl3) for 2b. The CD spectra showed that these two polymers had very similar and strong Cotton effects. Film polymer 2a showed almost the same PL spectrum as that in dilute CHCl3 solution, indicating that bulky POSS units strongly suppressed intermolecular aggregation of the π‐conjugated polymer backbone. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6035–6040, 2008
Random terpolymers for electroluminescent devices: Synthesis and characterization of new cyano‐containing poly(fluorenylene‐vinylene)s
Authors: Grisorio Roberto , Piliego Claudia , Fini Paola , Cosma Pinalysa , Mastrorilli Piero , Gigli Giuseppe , Suranna Gian Paolo , Nobile Cosimo Francesco
Published: August 2008

The synthesis of new random poly(2,7‐fluorenylene‐vinylene)s was achieved by a Suzuki–Heck cascade polymerization reaction. The poly(fluorenylene‐vinylene) base structure was modified by the regio‐random incorporation of 1‐cyano‐2,5‐phenylene as electron withdrawing unit (CN‐PFV1) and its properties were compared with terpolymers also embodying 1,4‐dioctyloxy‐2,5‐phenylene (CN‐PFV2) or 3,6‐N‐octylcarbazole (CN‐PFV3) as electron‐donating moieties. Thermal analysis revealed a high thermal stability (Td > 389 °C) and the absence of glass transitions for all polymers. Cyclic voltammetry indicated a high electron affinity of the materials (2.96–3.21 eV) attributed to the presence of the cyano‐containing comonomer. In dilute solutions, the copolymers showed a broad green fluorescence with quantum yields ranging from 0.42 to 0.79, while in the solid state, a relatively narrow emission centered at ∼ 560 nm, governed by the low‐energy segments within the π‐conjugated backbone, was observed. The electroluminescence properties of the materials were tested in OLED devices of ITO/PEDOT‐PSS/CN‐PFV1‐3/Ca/Al or ITO/PEDOT‐PSS/CN‐PFV1‐3/Alq3/Ca/Al configurations, showing a bright green‐yellow emission that, in the case of CN‐PFV2, reached 1403 cd/m2 with efficiencies as high as 0.13 cd/A. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6051–6063, 2008
Electrospray ionization mass spectrometric study of end‐groups in peroxydicarbonate‐initiated radical polymerization
Authors: Buback Michael , Frauendorf Holm , Janssen Olaf , Vana Philipp
Published: August 2008

Initiation by diethyl peroxydicarbonate (E‐PDC), di‐n‐tetradecyl peroxydicarbonate (nTD‐PDC), di‐n‐hexadecyl peroxydicarbonate (nHD‐PDC), and di‐2‐ethylhexyl peroxydicarbonate (2EH‐PDC) of free‐radical polymerizations of methyl methacrylate in benzene solution was studied by end‐group analysis via electrospray ionization mass spectrometry (ESI‐MS). Unambiguous assignment of ESI‐MS peaks allows for identification of the type of radical that starts chain growth. In case of initiation by dialkyl peroxydicarbonates with linear alkyl groups, almost exclusively alkoxy carbonyloxyl species, which are the primary fragments from initiator decomposition, occur as end‐groups. With 2EH‐PDC, however, both the primary 2‐ethylhexoxy carbonyloxyl fragment and a second moiety, which is formed by decarboxylation of the 2‐ethylhexoxy carbonyloxyl radical, are clearly observed as end‐groups. The decarboxylation process is described by a concerted mechanism which involves a 1,5‐hydrogen shift reaction. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6071–6081, 2008
Compensation in boron‐doped CVD diamond
Authors: Gabrysch Markus , Majdi Saman , Hallén Anders , Linnarsson Margareta , Schöner Adolf , Twitchen Daniel , Isberg Jan
Published: August 2008

Hall‐effect measurements on single crystal boron‐doped CVD diamond in the temperature interval 80–450 K are presented together with SIMS measurements of the dopant concentration. Capacitance–voltage measurements on rectifying Schottky junctions manufactured on the boron‐doped structures are also presented in this context. Evaluation of the compensating donor (ND) and acceptor concentrations (NA) show that in certain samples very low compensation ratios (ND/NA below 10–4) have been achieved. The influence of compensating donors on majority carrier transport and the significance for diamond device performance are briefly discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Band bending and quasi‐2DEG in the metallized β‐SiC(001) surface
Authors: Rurali R. , Wachowicz E. , Hyldgaard P. , Ordejón P.
Published: August 2008

We study the mechanism leading to the metallization of the β‐SiC(001) Si‐rich surface induced by hydrogen adsorption. We analyze the effects of band bending and demonstrate the existence of a quasi‐2D electron gas, which originates from the donation of electrons from adsorbed hydrogen to bulk conduction states. We also provide a simple model that captures the main features of the results of first‐principles calculations, and uncovers the basic physics of the process. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of the antiobesity effects of the protopanaxadiol‐ and protopanaxatriol‐type saponins of red ginseng
Authors: Kim Ji Hyun , Kang Soon Ah , Han Seung‐Moo , Shim Insop
Published: August 2008

A previous study demonstrated that ginseng crude saponins prevent obesity induced by a high‐fat diet in rats. Ginseng crude saponins are known to contain a variety of bioactive saponins. The present study investigated and compared the antiobesity activity of protopanaxadiol (PD) and protopanaxatriol (PT) type saponins, major active compounds isolated from crude saponins. Male 4‐week‐old Sprague‐Dawley rats were fed with normal diet (N) or high‐fat diet (HF). After 5 weeks, the HF diet group was subdivided into the control HF diet, HF diet‐PD and HF diet‐PT group (50 mg/kg/day, 3 weeks, i.p.). Treatment with PD and PT in the HF diet group reduced the body weight, total food intake, fat contents, serum total cholesterol and leptin to levels equal to or below the N diet group. The hypothalamic expression of orexigenic neuropeptide Y was significantly decreased with PD or PT treatment, whereas that of anorexigenic cholecystokinin was increased, compared with the control HF diet group. In addition, PD type saponins had more potent antiobesity properties than PT saponins, indicating that PD‐type saponins are the major components contributing to the antiobesity activities of ginseng crude saponins. The results suggest that the antiobesity activity of PD and PT type saponins may result from inhibiting energy gain, normalizing hypothalamic neuropeptides and serum biochemicals related to the control of obesity. Copyright © 2008 John Wiley & Sons, Ltd.
1D lead iodide crystals encapsulated within single walled carbon nanotubes
Authors: Kuganathan Navaratnarajah , Green Jennifer C.
Published: August 2008

The structure and binding energies of lead iodide crystals encapsulated within single‐walled carbon noanotubes are studied using density functional theory. Calculations were performed on the simulated PbI2 structure encapsulated within a (12,12) single‐walled nanotube, to investigate the perturbations on the PbI2 crystal and tube structure and electronic structure, and to estimate the binding energy. The calculation confirms the structure as a single chain of PbI6 octahedra bound by two chains of PbI5 square pyramids. The calculated binding energy shows that the encapsulation is noncovalent. Minimal charge transfer is observed between nanotube and the PbI2 crystals. The band gap is shown to increase from the bulk to the encapsulated structure. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Prediction of excited state energies for molecular nitrogen using quantum Monte Carlo methods
Authors: Fayton Floyd A. , Gibson Ainsley A. , Harkless John A. W.
Published: August 2008

Using the quantum Monte Carlo (QMC) method, we estimated electronic excitation energies for four low‐lying Frank–Condon states of dinitrogen. QMC trial function forms were examined, with single and multideterminant wave functions derived from configuration interaction (CI) and complete active space self‐consistent field theory (CASSCF) calculations. Variational Monte Carlo (VMC) and fixed‐node diffusion Monte Carlo (FN‐DMC) results compare favorably with TDHF, MRDCI, TDDFT, MR‐CCSD, EOM‐CCSD, and CASSCF which demonstrate the accuracy of QMC for these excited electronic states. The CASSCF constructed trial functions for QMC (QMC‐CAS) and MR‐CCSD deviate the least from the experimental values presented. Mean absolute deviation (MAD), or the difference between the calculated result and the experimental value divided by the total number of calculated results, is provided for each method. The least favorable MAD is obtained by the multideterminant and single determinant CISD trial function used for VMC calculations at 1.67 and 1.32, respectively. The lowest three MAD's are provided by the multideterminant CASSCF‐VMC (0.23), the multideterminant CASSCF‐DMC (0.14), and the MR‐CCSD (0.13) calculation. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Modeling enzymatic transition states by force field methods
Authors: Hansen M. B. , Jensen H. J. A. , Jensen F.
Published: August 2008

The SEAM method, which models a transition structure as a minimum on the seam of two diabatic surfaces represented by force field functions, has been used to generate 20 transition structures for the decarboxylation of orotidine by the orotidine‐5′‐monophosphate decarboxylase enzyme. The dependence of the TS geometry on the flexibility of the system has been probed by fixing layers of atoms around the active site and using increasingly larger nonbonded cutoffs. The variability over the 20 structures is found to decrease as the system is made more flexible. Relative energies have been calculated by various electronic structure methods, where part of the enzyme is represented by a force field description and the effects of the solvent are represented by a continuum model. The relative energies vary by several hundreds of kJ/mol between the transition structures, and tests showed that a large part of this variation is due to changes in the enzyme structure at distances more than 5 Å from the active site. There are significant differences between the results obtained by pure quantum methods and those from mixed quantum and molecular mechanics methods. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Proton transfer at the carboxylic sites of amino acids: A single water molecule catalyzed process
Authors: Yang Gang , Wu Xiaomin , Zu Yuangang , Liu Chengbu , Fu Yujie , Zhou Lijun
Published: August 2008

Ab initio calculations at MP2 level of theory were used to study the proton transfer at the carboxylic sites of amino acids, in the isolated, mono‐ and di‐hydrated forms. In the case of water dimer, two interaction modes with glycine neutral structures (see Fig. 3) were explored, corresponding to the concerted and stepwise reaction pathways. Their transition states can be described as (H2OHOH2)+ [Fig. 4(a)] and (H2O‐‐‐HOH2)+ [Fig. 4(b)], respectively. The energy analysis indicated that the concerted pathway is preferred. In the isolated, mono‐ and di‐hydrated glycine complexes, the activation barriers of the proton transfer at the carboxylic sites were calculated to be 34.49, 16.59, and 13.36 kcal mol−1, respectively. It was thus shown that the proton transfer is significantly assisted and catalyzed by water monomer so that it can take place at room temperature. Instead, the further addition of water molecules plays solvent effects rather than catalytic effects to this proton transfer process. The above results obtained with discrete water molecules were supported by the solvent continuum calculated data. It was also observed that the heavy dependence of the solvent continuum models on dipole moments may produce misleading results. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Theoretical study on the mechanism for the thermal rearrangement reactions of 2‐silylethyl acetate H3SiCH2CH2OCOCH3
Authors: Jia Zhongfeng , Feng Shengyu , Song Enfeng , Sun Wenyan , Cong Lixiao
Published: August 2008

The thermal rearrangement mechanisms of 2‐silylethylacetate H3SiCH2CH2OOCCH3 were investigated by ab initio molecular orbital theory for the first time. All structures of reactant, transition states, and products were located and fully optimized at the B3LYP/6‐311+G(d, p) levels, and harmonic vibrational frequencies for the involved stationary points on the potential energy surface were obtained. The reaction pathways were analyzed and confirmed by intrinsic reaction coordinate (IRC) calculations. Furthermore, atomic charges were determined by using the natural bond orbital (NBO) analysis. The calculational results show that H3SiCH2CH2OOCCH3 can rearrange thermally in two ways. One is [1,3] rearrangement (Reaction A), in which silyl group transfers from carbon to oxygen(in COC) via a four‐membered ring transition state, forming silyl acetate and ethylene, the other way, [1,5] rearrangement (Reaction B), happens with transferring of silyl group from carbon to oxygen (in CO) via a six‐membered ring transition state, forming the same products as in Reaction A. The energy barriers of the Reactions A and B were calculated to be 188.9 and 191.6 kJ/mol at the B3LYP/6‐311+G(d,p) levels, respectively. Changes in thermodynamic functions (ΔS, ΔH, and ΔG), equilibrium constant K(T), as well as preexponential factor A(T), and reaction rate constant k(T) in Eyring transition state theory were calculated over a temperature range of 200–1600 K, and then thermodynamic and kinetic properties of the reactions were analyzed. It can be suggested that Reactions A and B are noncompetitive, and both happen only at elevated temperature. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
A DFT study of transformation of nitrosothiol isomers and their decomposition to nitric oxide in gas phase
Authors: Ruangpornvisuti Vithaya
Published: August 2008

The structures of nitrosothiol isomers were obtained by geometry optimizations using the density functional theory calculations. Two cis‐isomeric, 2 trans‐isomeric, and 1 zwitterionic species of the HSNO isomers were found and the most stable species is the trans‐isomer. Energetics, thermodynamic properties, rate constants, equilibrium constants of all transformation reactions, and their energy profiles were obtained. Decomposition of the HSNO trans‐isomer to nitric oxide was investigated and its rate constant was obtained. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Simulations of Xe@C60 collisions with graphitic films
Authors: Albert Victor V. , Sabin John R. , Harris Frank E.
Published: August 2008

Collisions between Xe@C60 and sheets of graphite of various dimensions were simulated. A Tersoff many‐body potential modeled the interactions between carbon atoms and a Lennard‐Jones potential simulated the xenon‐carbon interactions. The simulations were compared to experiment and with simulations which implemented other potentials. The results indicate that a relatively small graphite film can be an accurate approximation for a nearly infinite sheet of graphite. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
A DFT study of infrared spectrum of sphingomyelin lipid molecule with calcium cation
Authors: Sugimori K. , Kawabe H. , Nagao H. , Nishikawa K.
Published: August 2008

One of the phospholipids, sphingomyelin (SM) is the most abundant component of mammalian membranes in brain and nervous tissues. It plays an important role for apoptosis, aging, and signal transduction with cations. Recently, Yappert and co‐workers have shown that human lens sphingomyelin and its hydrogenated derivative, dihydrosphingomyelin (DHSM) are interacted with Ca2+ ions to develop human cataracts. In this study, we investigate conformational differences between an isolated SM/DHSM molecule and Ca2+‐coordinated form by using density functional theory (DFT) calculations. B3LYP functional and 6‐31G(d,p) double‐ζ split‐valence basis set is used for geometry optimization and normal mode analysis. One of resultant conformers of SMs has hydrogen bonding between hydroxyl and phosphate group, whereas another conformer has hydrogen bonding between hydroxyl and amide group. The red shift of calculated vibrational frequencies of amide band due to Ca2+ is compared with experimental infrared spectrum. Finally, we discuss the Ca2+‐induced effects from conformational and spectroscopic point of view to compare the experimental results. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Robust stability andH∞control for uncertain discrete Markovian jump singular systems with mode‐dependent time‐delay
Authors: Ma Shuping , Zhang Chenghui
Published: August 2008

The robust stochastic stability, stabilization andH∞control for mode‐dependent time‐delay discrete Markovian jump singular systems with parameter uncertainties are discussed. Based on the restricted system equivalent (r.s.e.) transformation and by introducing new state vectors, the singular system is transformed into a standard linear system, and delay‐dependent linear matrix inequalities (LMIs) conditions for the mode‐dependent time‐delay discrete Markovian jump singular systems to be regular, causal and stochastically stable, and stochastically stable with γ‐disturbance attenuation are obtained, respectively. With these conditions, robust stabilization problem and robustH∞control problem are solved, and the LMIs sufficient conditions are obtained. A numerical example illustrates the effectiveness of the method given in the paper. Copyright © 2008 John Wiley & Sons, Ltd.
Quality of life evaluation in patients affected by osteoarthritis secondary to congenital hip dysplasia after total hip replacement
Authors: Tellini Alessandra , Ciccone Vincenza , Blonna Davide , Rossi Roberto , Marmotti Antongiulio , Castoldi Filippo
Published: August 2008

Background

The aim of the study was to evaluate the quality of life (QoL) in patients affected by osteoarthritis (OA) secondary to congenital hip dysplasia (CHD) and treated by hip arthroplasty.

Methods

We prospectively treated 40 patients admitted to our hospital between 2001 and 2006. Each patient was asked to answer to two questionnaires: WOMAC and MOS SF-36. Patients were evaluated four months before surgery and once they had achieved postoperative rehabilitation. Pre- and postoperative results were analyzed and compared with the international literature on patients affected by OA and also with a healthy population.

Results

Pre- and post-operative results: WOMAC: pain 14.06–0.84; stiffness 4.26–0.52; function 42.68–5.39. SF-36: physical function 18.55–84.52; role physical 28.33–87.10; body pain 23.26–83.39; general health 55.19–81.74; vitality 32.74–72.10; social function 43.55–84.66; role emotional 68.82–93.55; mental health 48.77–79.35. All results were statistically significant.

Conclusions

The study reports an important QoL improvement in patients affected by arthritis secondary to CHD that underwent hip surgery, and underlines differences with respect to primary OA. QoL evaluation cannot replace either clinical and instrumental evaluation or the physician’s experience, but it can give weight to the patient’s expectations, and may be considered an efficient test for medical and surgical treatments.
Segond fracture with anterior cruciate ligament tear in an adolescent
Authors: Falciglia F. , Mastantuoni G. , Guzzanti V.
Published: August 2008

The authors report a case of acute knee injury in a 14-year-old teenager. The X-ray showed a so-called Segond’s fracture: a small avulsed bone fragment, elliptical in shape, lying immediately below the external tibial plateau, a few millimeters from the lateral tibial cortex. The fracture site was in the portion of the tibial condyle which is linked to the middle third of the lateral capsule by meniscal tibial fibers. Clinical examination under anesthesia and subsequent arthroscopy revealed a total intrasubstance ACL (anterior cruciate ligament) tear close to the proximal insertion. The authors confirm Segond’s report of a possible association of this avulsion fracture with ACL injuries, even in adolescence.
Hyperlipidemia in glycogen storage disease type III: Effect of age and metabolic control
Authors: Bernier A. V. , Sentner C. P. , Correia C. E. , Theriaque D. W. , Shuster J. J. , Smit G. P. A. , Weinstein D. A.
Published: August 2008

While the presence of hyperlipidaemia in glycogen storage disease (GSD) type Ia and Ib is generally accepted, few investigators have adequately assessed lipid profiles of GSD III in children, in whom the presence of hyperlipidaemia may be most prominent. We analysed the lipid profiles in 44 GSD III patients from 6 months to 30 years of age. Hypertriglyceridaemia and hypercholesterolaemia were common in children younger than 3 years of age. Hypertriglyceridaemia correlated negatively with age, and may reflect increased severity of hypoglycaemia in this younger population. The presence of hyperlipidaemia during childhood in these patients identifies another GSD population that could be at risk for early cardiovascular disease (CVD). Consequently, the outcome of clinical trials investigating the vascular effect of hyperlipidaemia in GSD applies to types other than GSD I.
Effect of Aspect Ratio on Field Emission Properties of ZnO Nanorod Arrays
Authors: Qian Xuemin , Liu Huibiao , Guo Yanbing , Song Yinglin , Li Yuliang
Published: August 2008

ZnO nanorod arrays are prepared on a silicon wafer through a multi-step hydrothermal process. The aspect ratios and densities of the ZnO nanorod arrays are controlled by adjusting the reaction times and concentrations of solution. The investigation of field emission properties of ZnO nanorod arrays revealed a strong dependency on the aspect ratio and their density. The aspect ratio and spacing of ZnO nanorod arrays are 39 and 167 nm (sample C), respectively, to exhibit the best field emission properties. The turn-on field and threshold field of the nanorod arrays are 3.83 V/μm and 5.65 V/μm, respectively. Importantly, the sample C shows a highest enhancement of factorβ, which is 2612. The result shows that an optimum density and aspect ratio of ZnO nanorod arrays have high efficiency of field emission.
The impact of supply chain complexity on manufacturing plant performance
Authors: Bozarth Cecil C. , Warsing Donald P. , Flynn Barbara B. , Flynn E. James
Published: August 2008

This paper puts forth a model of supply chain complexity and empirically tests it using plant‐level data from 209 plants across seven countries. The results show that upstream complexity, internal manufacturing complexity, and downstream complexity all have a negative impact on manufacturing plant performance. Furthermore, supply chain characteristics that drive dynamic complexity are shown to have a greater impact on performance than those that drive only detail complexity. In addition to providing a definition and empirical test of supply chain complexity, the study serves to link the systems complexity literature to the prescriptions found in the flexibility and lean production literatures. Finally, this research establishes a base from which to extend previous work linking operations strategy to organization design [Flynn, B.B., Flynn, E.J., 1999. Information‐processing alternatives for coping with manufacturing environment complexity. Decision Sciences 30 (4), 1021–1052].
Daily supplementation of tocotrienol-rich fraction or α-tocopherol did not induce immunomodulatory changes in healthy human volunteers
Authors: Radhakrishnan Ammu K. , Lee Ai-Ling , Wong Pak-Fong , Kaur Jagmohni , Aung Htin , Nesaretnam Kalanithi
Published: August 2008

Vitamin E is divided into two subgroups; tocopherols and tocotrienols. Both have protective roles in biological systems. The present study was conducted to compare the effect of short-term supplementation at 200 mg/d of either α-tocopherol or a tocotrienol-rich fraction (TRF) from palm oil on immune modulation and plasma vitamin E levels in normal healthy Asian volunteers. In a randomised, double-blind placebo-controlled trial conducted, fifty-three healthy volunteers aged 20–50 years were recruited based on the study's inclusion and exclusion criteria. They were randomly assigned into three groups, i.e. two experimental groups that received daily supplementation at 200 mg of either α-tocopherol or the TRF, and the control group that received a placebo. Blood was drawn on days 0, 28 and 56 for several laboratory analyses. Differences in the production of IL-4 or interferon-γ by concanavalin A-stimulated lymphocytes isolated from these volunteers were not significant (P>0·05). There were no significant differences observed in immune parameters between the healthy volunteers who received daily supplementation with either α-tocopherol or the TRF. As these observations were made in the absence of any immunogenic challenge, we feel it would be of benefit to study if there would be any differences observed when an immunogenic challenge such as vaccination were introduced.
Niacin for dairy cattle: a review
Authors: Niehoff Inka-Donata , Hüther Liane , Lebzien Peter
Published: August 2008

Due to the incorporation of niacin into the coenzymes NAD and NADP, niacin is of great importance for the metabolism of man and animals. Apart from niacin in feed and endogenous formation, microbial niacin synthesis in the rumen is an important source for dairy cows. But the amount synthesised seems to differ greatly, which might be influenced by the ration fed. Many studies revealed a positive impact of a niacin supplementation on rumen protozoa, but microbial protein synthesis or volatile fatty acid production in the rumen showed inconsistent reactions to supplemental niacin. The amount of niacin reaching the duodenum is usually higher when niacin is fed. However, not the whole quantity supplemented reaches the duodenum, indicating degradation or absorption before the duodenal cannula. Furthermore, supplementation of niacin did not always lead to a higher niacin concentration in blood. Effects on other blood parameters have been inconsistent, but might be more obvious when cows are in a tense metabolic situation, for example, ketosis or if high amounts are infused post-ruminally, since ruminal degradation appears to be substantial. The same is valid for milk parameters. In the few studies where blood niacin and milk parameters have been investigated, enhanced niacin concentrations in blood did not necessarily affect milk production or composition. These results are discussed in the present review, gaps of knowledge of niacin's mode of action on the metabolism of dairy cows are identified and directions for future research are suggested.
Hoarseness due to Mycobacterium kansasii
Authors: Wray D , Oko M O , Boldy D A R , Butt M T
Published: August 2008

Objective:

To present a case of unilateral vocal fold paralysis due to Mycobacterium kansasii induced pressure on the left recurrent laryngeal nerve, a specific aetiology not previously reported in the world literature.

Case report:

A 57-year-old Caucasian man presented with a short history of productive cough, fever, hoarseness and 14-kg weight loss. He was a smoker, had an abnormal chest X-ray and was human immunodeficiency virus negative. A sputum sample was positive on direct microscopy for acid fast bacilli. Initially, the patient was treated with Rifater (rifampicin, isoniazid and pyrazinamide) and ethambutol. Mycobacterium kansasii was isolated and proved sensitive to this antimycobacterial treatment. Nasoendoscopy revealed diminished movement of the left vocal fold, and a computed tomography scan showed enlarged mediastinal lymph nodes anterior to the aortic arch. After three months of antimycobacterial treatment, the vocal folds were fully mobile at repeat nasoendoscopy, and this coincided with gradual resolution of the patient's hoarseness and weight loss.

Conclusions:

There are many causes of unilateral vocal fold paralysis. This case illustrates the importance of anatomical knowledge in reaching a diagnosis, and also presents the first reported case of Mycobacterium kansasii creating this clinical picture.
Editorial
Authors: Bolton Kingsley , Graddol David , Mesthrie Rajend
Published: August 2008

We like to think that English Today provides a record of the changing fortunes of English in different parts of the world – evolving patterns of its use, changes in status and attitudes towards it, and developments in local forms. In this issue our contributors provide us with such reports from Europe to Asia.
From global language use to local meanings: English in Finnish public discourse
Authors: Taavitsainen Irma , Pahta Päivi
Published: August 2008

In 2002, Tom McArthur, then editor of English Today, visited Helsinki and asked Irma Taavitsainen and Päivi Pahta whether the use of English in Finland was becoming more like its Nordic neighbours. In an article in ET76 they answered with a cautious ‘yes’. Now the authors provide us with an update, with examples of how English is currently used in Finnish public communication.
English as an international language? Taiwanese university teachers' dilemma and struggle…
Authors: Lai Hsuan-Yau Tony
Published: August 2008

This study aims to explore university English teachers' perceptions of the role of English today in Taiwan from two aspects – the ownership of English and acquiring target language culture in the English language classroom. The concept of English as an international language (EIL) or English as a lingua franca (ELF) has been discussed extensively in the ELT field for many years. Theoretically the concept promotes the idea that English is no longer a possession of any particular English-speaking countries and that there are many different varieties of Englishes. Since teachers are an important – if not the most important – influence in the language classroom, their perceptions are likely to affect the students profoundly. In spite of the theoretical discussion of EIL, in reality, what do university English teachers in Taiwan think about the role of English today? In the study, five experienced teachers were invited for a focus group interview to discuss these issues. The results suggest that university English teachers in Taiwan are facing a dilemma and struggle to follow the notion of EIL (or ELF) in the classroom.
Swiss ‘cool’
Authors: Davidson Keith
Published: August 2008

The cachet of English in the Swiss press. Plurlingual Switzerland has three ‘official’ languages, standard forms of German, French, Italian, and a further ‘national’ language, the ancient Latin dialects of Romansh spoken in the eastern Alpine valleys by less than one per cent of the population. But there are problems for the Swiss in learning each other's languages. And, as in other as in other European countries, there is an increasing range of other mother tongues. Little wonder, then, that the Swiss readily resort to English in talking to each other, and little wonder at a marked role for English in the Swiss media.
English as a Lingua Franca: form follows function
Authors: Cogo Alessia
Published: August 2008

In this paper I wish to respond to the article published in ET94 by Saraceni while at the same time providing some clarifications concerning the concept of English as a Lingua Franca (henceforth ELF). In his article Saraceni raises three main questions (and a number of related debatable comments which I will quickly deal with in my final remarks) regarding: 1) the nature of ELF and its speakers, 2) the relationship between ELF and the World Englishes (henceforth WE) paradigm, and 3) the distinction between form and function. I will address each of these questions, and in so doing consider a number of notions concerning the ELF research field.
Einstein's Unpublished Opening Lecture for His Course on Relativity Theory in Argentina, 1925
Authors: Gangui Alejandro , Ortiz Eduardo L.
Published: August 2008

In 1922 the University of Buenos Aires (UBA) Council approved a motion to send an invitation to Albert Einstein to visit Argentina and give a course of lectures on his theory of relativity. The motion was proposed by Jorge Duclout (1856–1927), who had been educated at the Eidgenössische Technische Hochschule, Zurich (ETH). This proposal was the culmination of a series of initiatives of various Argentine intellectuals interested in the theory of relativity. In a very short time Dr. Mauricio Nirenstein (1877–1935), then the university's administrative secretary, fulfilled all the requirements for the university's invitation to be endorsed and delivered to the sage in Berlin. The visit took place three years later, in March–April 1925.
Majority Bootstrap Percolation on the Hypercube
Authors: BALOGH JÓZSEF , BOLLOBÁS BÉLA , MORRIS ROBERT
Published: August 2008

In majority bootstrap percolation on a graph G, an infection spreads according to the following deterministic rule: if at least half of the neighbours of a vertex v are already infected, then v is also infected, and infected vertices remain infected forever. We say that percolation occurs if eventually every vertex is infected.

The elements of the set of initially infected vertices, A ⊂ V(G), are normally chosen independently at random, each with probability p, say. This process has been extensively studied on the sequence of torus graphs [n]d, for n = 1,2, . . ., where d = d(n) is either fixed or a very slowly growing function of n. For example, Cerf and Manzo [17] showed that the critical probability is o(1) if d(n) ≤ log*n, i.e., if p = p(n) is bounded away from zero then the probability of percolation on [n]d tends to one as n → ∞.

In this paper we study the case when the growth of d to ∞ is not excessively slow; in particular, we show that the critical probability is 1/2 + o(1) if d ≥ (log log n)2 log log log n, and give much stronger bounds in the case that G is the hypercube, [2]d.
What do babies eat? Evaluation of a food frequency questionnaire to assess the diets of infants aged 12 months
Authors: Marriott Lynne D , Inskip Hazel M , Borland Sharon E , Godfrey Keith M , Law Catherine M , Robinson Sian M ,   The Southampton Women’s Survey Study Group
Published: August 2008

Objective

To evaluate the relative validity of an FFQ for assessing nutrient intakes in 12-month-old infants.

Design and setting

The FFQ was developed to assess the diets of infants born to women in the Southampton Women’s Survey (SWS), a population-based survey of young women and their offspring. The energy and nutrient intakes obtained from an interviewer-administered FFQ were compared with those obtained from 4d weighed diaries (WD).

Subjects and methods

A sub-sample of fifty infants (aged 1 year) from the SWS had their diets assessed by both methods. The FFQ recorded the frequencies and amounts of foods and drinks consumed by the infants over the previous 28 d; milk consumption was recorded separately. The WD recorded the weights of all foods and drinks consumed by the infants on 4 d following the FFQ completion.

Results

The Spearman rank correlation coefficients for intakes of energy, macronutrients and eighteen micronutrients, determined by the two methods, ranged from r = 0·25 to 0·66. Bland–Altman statistics showed that mean differences between methods were in the range +5 % to +60 % except for vitamin D (+106 %). Differences in micronutrient intake were partly explained by changes in patterns of milk consumption between the two assessments.

Conclusion

Although there were differences in absolute energy and nutrient intakes between methods, there was reasonable agreement in the ranking of intakes. The FFQ is a useful tool for assessing energy and nutrient intakes of healthy infants aged around 12 months.
Sociodemographic risk factors associated with metabolic syndrome in a Mediterranean population
Authors: Buckland Genevieve , Salas-Salvadó Jordi , Roure Eulàlia , Bulló Mònica , Serra-Majem Lluís
Published: August 2008

Objective

To investigate the sociodemographic risk factors associated with metabolic syndrome (MetS) in the Mediterranean population of Catalonia, Spain.

Design and setting

Data from the cross-sectional, population-based 2002–2003 Health Survey of Catalonia were analysed. The survey used a structured questionnaire to collect information on demographics, lifestyle and medical history. In a sub-sample of the original survey population anthropometrics and blood pressure were measured and blood samples were taken to determine HDL cholesterol, TAG and fasting glucose.

Subjects

The analysis included the 1104 individuals aged 18–74 years from this sub-sample who had complete information on all variables necessary to define MetS using the National Cholesterol Education Program’s Adult Treatment Panel III (ATP III) and the International Diabetes Federation (IDF) criteria.

Results

MetS prevalence was 28·5 % and 24·8 % according to IDF and ATP III criteria, respectively. MetS was significantly (P = 0·05) more common in males than females. MetS prevalence increased significantly (P<0·001) with age and degree of adiposity and as social class decreased. In general, MetS prevalence decreased as physical activity increased, which was significant (P = 0·0253) when applying ATP III criteria. After taking into account important confounders, MetS prevalence was significantly positively associated with male gender, age, BMI, physical inactivity and lower social class. Smoking status, marital status and working situation were not independently associated with MetS.

Conclusions

Age, sex, degree of adiposity, physical activity and social class are the sociodemographic risk factors independently associated with MetS in this Mediterranean population. Understanding which factors predict MetS is important considering likely increasing MetS trends, and is useful for determining public health strategies.
A cross-cultural comparison of dietary intakes and physical activity between American and Czech school-aged children
Authors: Humenikova Shriver Lenka , Gates Gail
Published: August 2008

Objective

The prevalence of child overweight in the Czech Republic is substantially lower than that in the USA. The objective of the present pilot study was to explore dietary intakes, frequency of dining in fast-food establishments, and the amount and intensity of physical activity between a sample of American and Czech children.

Design

A cross-sectional correlational pilot study.

Setting

Four public schools in the USA and four public schools in the Czech Republic.

Subjects

Ninety-five Czech and forty-four American 4–6th graders from urban public schools participated in the study. Dietary intake and number of fast-food visits were evaluated using two multiple-pass 24 h recalls. Physical activity was measured using the modified Self-Administered Physical Activity Checklist.

Results

American children (mean age 10·8 (se 0·2) years) consumed more energy and fat, less fruits and vegetables, more soft drinks, and visited fast-food establishments more often than Czech children (mean age 11·0 (se 0·1) years). Although no differences were found in vigorous activity by nationality, Czech children spent significantly more time in moderate physical activities than American children.

Conclusions

Despite the influx of some negative Western dietary trends into the country, Czech children had a healthier diet and were more physically active than American children. Further research is warranted to determine whether the same differences in dietary intakes, physical activity and fast-food visits exist between nationally representative samples of American and Czech children.