bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Hamiltonian structure of Hirota‐Kimura discretization of the Euler top
Authors: Petrera Matteo , Suris Yuri B.
Published: September 2010

This paper deals with a remarkable integrable discretization of the so (3) Euler top introduced by Hirota and Kimura. Such a discretization leads to an explicit map, whose integrability has been understood by finding two independent integrals of motion and a solution in terms of elliptic functions. Our goal is the construction of its Hamiltonian formulation. After giving a simplified and streamlined presentation of their results, we provide a bi‐Hamiltonian structure for this discretization, thus proving its integrability in the standard Liouville‐Arnold sense (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On a class of extremal solutions of a moment problem for rational matrix‐valued functions in the nondegenerate case I
Authors: Fritzsche Bernd , Kirstein Bernd , Lasarow Andreas
Published: September 2010

The main theme of this paper is the discussion of a parametrized family of solutions of a finite moment problem for rational matrix‐valued functions in the nondegenerate case. We will show that each member of this family is extremal in several directions concerning some point of the open unit disk. These investigations are inspired by the authors' paper [23], where a similar topic is studied in the context of the matricial Carathéodory problem. We will see that larger parts of the results presented there can be extended to the rational case studied here.The main theme of this paper is the discussion of a parametrized family of solutions of a finite moment problem for rational matrix‐valued functions in the nondegenerate case. We will show that each member of this family is extremal in several directions concerning some point of the open unit disk. These investigations are inspired by the authors' paper [23], where a similar topic is studied in the context of the matricial Carathéodory problem. We will see that larger parts of the results presented there can be extended to the rational case studied here (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dual‐echo Dixon imaging with flexible choice of echo times
Authors: Eggers Holger , Brendel Bernhard , Duijndam Adri , Herigault Gwenael
Published: September 2010

In this work, a new two‐point method for water–fat imaging is described and explored. It generalizes existing two‐point methods by eliminating some of the restrictions that these methods impose on the choice of echo times. Thus, the new two‐point method promises to provide more freedom in the selection of protocol parameters and to reach higher scan efficiency. Its performance was studied theoretically and was evaluated experimentally in abdominal imaging with a multigradient‐echo sequence. While depending on the choice of echo times, it is generally found to be favorable compared to existing two‐point methods. Notably, water images with higher spatial resolution and better signal‐to‐noise ratio were attained with it in single breathholds at 3.0 T and 1.5 T, respectively. The use of more accurate spectral models of fat is shown to substantially reduce observed variations in the extent of fat suppression. The acquisition of in‐ and opposed‐phase images is demonstrated to be replaceable by a synthesis from water and fat images. The new two‐point method is finally also applied to autocalibrate a multidimensional eddy current correction and to enhance the fat suppression achieved with three‐point methods in this way, especially toward the edges of larger field of views. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Immobilized contrast‐enhanced MRI: Gadolinium‐based long‐term MR contrast enhancement of the vein graft vessel wall
Authors: Mitsouras Dimitris , Vemula Praveen Kumar , Yu Peng , Tao Ming , Nguyen Binh T. , Campagna Christina M. , Karp Jeffrey M. , Mulkern Robert V. , Ozaki C. Keith , Rybicki Frank J.
Published: September 2010

An implantable MR contrast agent that can be covalently immobilized on tissue during surgery has been developed. The rationale is that a durable increase in tissue contrast using an implantable contrast agent can enhance postsurgical tissue differentiation using MRI. For small‐vessel (e.g., vein graft) MRI, the direct benefit of such permanent “labeling” of the vessel wall by modification of its relaxation properties is to achieve more efficient imaging. This efficiency can be realized as either increased contrast leading to more accurate delineation of vessel wall and lesion tissue boundaries, or, faster imaging without penalizing contrast‐to‐noise ratio, or a combination thereof. We demonstrate, for the first time, stable long‐term MRI enhancement using such an exogenous contrast mechanism based on immobilizing a modified diethylenetriaminepentaacetic acid gadolinium3+ dihydrogen complex on a human vein using a covalent amide bond. Signal enhancement due to the covalently immobilized contrast agent is demonstrated for excised human vein specimens imaged at 3 T, and its long‐term stability is demonstrated during a 4‐month incubation period. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Elasto‐plastic seepage‐induced stresses due to tunneling
Authors: Shin Jong‐Ho , Lee In‐Mo , Shin Young‐Jin
Published: September 2010

When tunneling is carried out beneath the groundwater table, hydraulic boundary is altered, resulting in seepage entering into the tunnel. The development of flow into the tunnel induces seepage stresses in the ground and the lining is subjected to additional loads. This can often cause fine particles to move, which clog the filter resulting in the long‐term hydraulic deterioration of the drainage system. However, the effect of seepage force is generally not considered in the analysis of tunnel. While several elastic solutions have been proposed by assuming seepage in an elastic medium, stress solutions have not been considered for the seepage force in a porous elasto‐plastic medium. This paper documents a study that investigates the stress behavior, caused by seepage, of a tunnel in an elasto‐plastic ground and its effects on the tunnel and ground. New elasto‐plastic solutions that adopt the Mohr–Coulomb failure criterion are proposed for a circular tunnel under radial flow conditions. A simple solution based on the hydraulic gradient obtained from a numerical parametric study is also proposed for practical use. It should be noted that the simple equation is useful for acquiring additional insight into a problem on a tunnel under drainage, because only a minimal computational effort is needed and considerable economic benefits can be gained by using it in the preliminary stage of tunnel design. The proposed equations were partly validated by numerical analysis, and their applicability is illustrated and discussed using an example problem. Comments on the tunnel analysis are also provided. Copyright © 2010 John Wiley & Sons, Ltd.
Stochastic finite element modelling of water flow in variably saturated heterogeneous soils
Authors: Mousavi Nezhad M. , Javadi A. A. , Abbasi F.
Published: September 2010

Water flow is greatly influenced by the characteristics of the domain through which the process occurs. It is generally accepted that earth materials have extreme variations from point to point in space. Consequently, this heterogeneity results in high variation in hydraulic properties of soil. In order to develop an accurate predictive model for transport processes in soil, the effects of this variability should be considered. In this study a two‐dimensional stochastic finite element flow model was developed for simulation of water flow through unsaturated soils. In this model, the stochastic partial differential governing equation of water flow, obtained from implementation of the perturbation‐spectral stochastic method on classical Richard's equation, was solved using a finite element method in the space domain and a finite difference scheme in the time domain. The effective hydrological parameters embedded in the mathematical model depend on time derivatives of capillary tension head; this makes possible to consider the hysteresis due to large‐scale variability of soil hydrological properties. The model is also capable of simulating infiltration and evaporation events and rapid change in the land surface boundary condition from one type event to another, based on a scheme used in the model for implementation of land surface boundary condition. The model was validated with the data obtained from a layered lysimeter test. The model was also used to simulate water flow under a long irrigation furrow. The results obtained with this model show better agreement with experimental measurements in comparison with a deterministic model. The possible reason for this agreement is that in the developed model, the influence of the variability of the properties of soil and effects of parameter hysteresis on water flow and water content redistribution are considered. Copyright © 2010 John Wiley & Sons, Ltd.
Rheological study on high‐density polyethylene/organoclay composites
Authors: Tang Youhong , Yang Cheng , Gao Ping , Ye Lin , Zhao Chengbi , Lin Wei
Published: September 2010

Maleic anhydride‐grafted polyethylene (MAPE) is investigated as a compatibilizer of polyethylene/organoclay nanocomposite. With MAPE help, partial exfoliation of the organoclay occurs in the nanocomposites with the melt compounding method for organoclay loading up to 8.0 wt%. Investigation of the rheological behaviors shows that at high frequencies or shear rates, the viscosity is essentially unaffected by the presence of organoclay; however, at low frequencies or shear rates, viscoelastic behavior alters dramatically, and this is attributed to the presence of anisotropic stacks of randomly oriented organoclay sheets and the formation of network structures. The important observations are firstly the initial stress overshooting observed in steady shear. At low shear rates, stress is much greater at the initial stage than the stress at the steady state; however, it can be eliminated by preshear at low shear rates, which means that preshearing can effectively break down the network structures and align the organoclay. Second, the normalized stress at the overshoot point is a function of the critical strain unit. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
Biobased polyurethanes from polyether polyols obtained by ionic‐coordinative polymerization of epoxidized methyl oleate
Authors: Del Rio E. , Lligadas G. , Ronda J. C. , Galià M. , Cádiz V.
Published: September 2010

A series of poly(ether urethane) networks were synthesized from polyether polyols obtained by ionic‐coordinative polymerization of epoxidized methyl oleate (EMO) using 4,4′‐methylenebis(phenyl isocyanate) or l‐lysine diisocyanate as coupling agents. Moreover, a variety of segmented poly(ether urethane) networks with different hard segment contents were obtained using 1,3‐propanediol as the chain extender. The materials were characterized by differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis, and tensile properties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Block copolymers based on 2‐vinyl‐4,4‐dimethyl‐5‐oxazolone by RAFT polymerization: Experimental and computational studies
Authors: Pascual Sagrario , Blin Thomas , Saikia Prakash J. , Thomas Michel , Gosselin Pascal , Fontaine Laurent
Published: September 2010

The ability of 2‐vinyl‐4,4‐dimethyl‐5‐oxazolone (VDM), a highly reactive functional monomer, to produce block copolymers by reversible addition fragmentation chain transfer (RAFT) sequential polymerization with methyl acrylate (MA), styrene (S), and methyl methacrylate (MMA) was investigated using cumyl dithiobenzoate (CDB) and 2‐cyanoisopropyl dithiobenzoate (CPDB) as chain transfer agents. The results show that PS‐b‐PVDM and PMA‐b‐PVDM well‐defined block copolymers can be prepared either by polymerization of VDM from PS‐ and PMA‐macroCTAs, respectively, or polymerization of S and MA from a PVDM‐macroCTA. In contrast, PMMA‐b‐PVDM block copolymers with controlled molecular weight and low polydispersity can only be obtained by using PMMA as the macroCTA. Ab initio calculations confirm the experimental studies. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Polysiloxane‐containing benzoxazine moieties in the main chain
Authors: Aydogan Binnur , Sureka Dilek , Kiskan Baris , Yagci Yusuf
Published: September 2010

Polysiloxanes containing thermally curable benzoxazine units in the main chain have been synthesized. For this purpose, first the diallyl functional benzoxazine monomer is synthesized through the Mannich and respective ring closing reactions of 4,4′‐isopropylidenediphenol (bisphenol A), formaldehyde, and allyamine. Subsequent hydrosilylation reaction of the resulting allylic monomer (B‐ala) with 1,1,3,3‐tetramethyldisiloxane (TMDS) in the presence of Pt catalyst yields the corresponding oligo(B‐ala‐tetramethyldisiloxane)s (OBTMDS). Using the anionic polymerization route, OBTMDS was then converted to poly(bisbenzoxazinedimethylsiloxane)s (PBDMSs) by reacting with readily available cyclic oligomer octamethylcyclotetrasiloxane (D4) or decamethylcyclopentasiloxane (D5) in the presence of tetrabutylammonium hydroxide as catalyst. The structures of the precursor diallyl monomer, the intermediate oligomer, and the resulting polymers are confirmed by Fourier transform infrared and 1H NMR analysis. Curing behavior of the products at various stages has also been studied by differential scanning calorimetry. Flexible transparent films of the PBDMSs are obtained by solvent casting. Thermal properties of the cured polymers are also investigated by thermogravimetric analysis. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Measuring true electromechanical strain of electroactive thermoplastic elastomer gels using synchrotron SAXS
Authors: Kim Bori , Park Younduk , Kim Jungahn , Hong Soon Man , Koo Chong Min
Published: September 2010

The true electric actuation thickness strain of poly (styrene‐b‐ethylbutylene‐b‐styrene) (SEBS) gel was measured using an in situ synchrotron SAXS. The thermoplastic elastomer SEBS gel was microphase‐separated to form a disordered styrene micelle nanostructure in an oil‐swollen ethylbutylene matrix. The SEBS gel showed reversible cyclic load–unload compression behavior without permanent residual strain. The electromechanical strain of the SEBS gel with carbon paste electrodes could be evaluated by means of a nanostructure dimensional change traced by using the in situ synchrotron SAXS during actuation. The strain measured with SAXS was compared with the strain measured using conventional laser displacement sensor systems. The optical laser sensor method was likely to overestimate the thickness strain due to the bending movement of the dielectric elastomer. To our knowledge, the thickness strain value measured by the synchrotron SAXS is the closest to the true strain ever measured in the field of dielectric elastomer studies, because the nanostructure dimensional change depends on the thickness dimension change, not on the translational movement like the bending motion. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010
Microfluidic channels fabricated on mesoporous electrospun fiber mats: A facile route to microfluidic chips
Authors: Jo Eunmin , Lim Min‐Cheol , Kim Han‐Nah , Paik Hyun‐Jong , Kim Young‐Rok , Jeong Unyong
Published: September 2010

We report a facile way of preparing microfluidic channels filled with electrospun functional fibers. Patterned elastic molds were in tight contact with electrospun fiber mats without any leak of the analyte solution. As an example of the simple devices, we demonstrated a microfluidic protein chip selectively purifying histidine‐tagged proteins. Highly mesoporous nitrilotriacetic acid‐functionalized polystyrene (PS‐NTA) fibers were produced by taking advantage of interpenetrating phase separation between PS and PEO during electrospinning. The specific interaction of Ni‐complexed PS‐NTA fibers with histidine enabled us to immobilize only target proteins from highly heterogeneous protein mixtures. The easy process to fabricate functionalized microchannels combined with the high production throughput from electrospinning may greatly contribute to chip‐based chromatographic and bioanalytical devices. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Nasal potential measurements on the nasal floor and under the inferior turbinate: Does it matter?
Authors: Vermeulen François , Proesmans Marijke , Feyaerts Nathalie , De Boeck Kris
Published: September 2010

Aim

Measurement of nasal potential difference (NPD) is increasingly used as diagnostic test for cystic fibrosis (CF) and for in vivo evaluation of treatments aimed at correcting the defective function of the cystic fibrosis transmembrane regulator (CFTR) protein. Several methods are used to measure NPD. This study explores the influence of the site of measurement and compares NPD results obtained on the nasal floor and under the inferior turbinate.

Methods

NPD was measured in 34 CF, 26 heterozygote, and 61 control subjects. In every subject, measurements were taken simultaneously under the inferior turbinate in one nostril, and on the nasal floor in the other nostril. Criteria for interpretable tracings were predefined. Repeat measurements were done in 57 persons.

Results

More interpretable tracings were obtained under the turbinate (120/124) than on the nasal floor (109/124), P = 0.015. Within each subject group, mean values obtained were similar for maximal basal potential, response to amiloride, and total chloride response. Both techniques discriminate well between CF and controls. Repeatability was similar with both methods: mean differences between two measurements approximated zero for most values. Also after correction for different number of interpretable tracings, simulation of sample size calculation for use in CFTR corrective trials was slightly in favor of measurements obtained on the nasal floor.

Conclusion

NPD measurements under the inferior turbinate and on the nasal floor have similar discriminative power for diagnostic use. Measurements under the turbinate result in a slightly higher proportion of interpretable tracings but sample size calculation slightly favors the nasal floor method. Pediatr. Pulmonol. 2011; 46:145–152. © 2011 Wiley‐Liss, Inc.
Estimating binding affinities by docking/scoring methods using variable protonation states
Authors: Park Min‐Sun , Gao Cen , Stern Harry A.
Published: September 2010

To investigate the effects of multiple protonation states on protein–ligand recognition, we generated alternative protonation states for selected titratable groups of ligands and receptors. The selection of states was based on the predicted pK
a of the unbound receptor and ligand and the proximity of titratable groups of the receptor to the binding site. Various ligand tautomer states were also considered. An independent docking calculation was run for each state. Several protocols were examined: using an ensemble of all generated states of ligand and receptor, using only the most probable state of the unbound ligand/receptor, and using only the state giving the most favorable docking score. The accuracies of these approaches were compared, using a set of 176 protein–ligand complexes (15 receptors) for which crystal structures and measured binding affinities are available. The best agreement with experiment was obtained when ligand poses from experimental crystal structures were used. For 9 of 15 receptors, using an ensemble of all generated protonation states of the ligand and receptor gave the best correlation between calculated and measured affinities. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Six sigma project to improve a management of change process
Authors: Garland R. Wayne
Published: September 2010

Many companies including Eastman Chemical Company (Eastman) are using Six Sigma teams and methodologies to improve their manufacturing processes. Eastman has also been successful in applying Six Sigma to process safety management. A Six Sigma Team was chartered to identify and implement improvements in the Eastman company management of change (MOC) process. Six sigma analysis tools utilized included process maps, cause & effects matrix, and failure modes & effects analysis. Improvement opportunities were identified for five parts of the MOC process. An improved MOC design and a control plan to maintain the gains were developed. This article shows how the Six Sigma approach is used to give an effective and efficient MOC process. © 2010 American Institute of Chemical Engineers Process Saf Prog, 2011
Optimizing reformer tube life through advanced inspection and remaining life assessment
Authors: Shannon B.E. , Jaske C.E. , Smith M.C.
Published: September 2010

Steam reformer tubes must withstand high temperature and pressures during operation and are made from centrifugally cast materials, typically HK‐40, HP modified, and microalloy materials. As operating conditions can result in various forms of damage, the identification and quantification of damage is of vital importance if tube life is to be predicted accurately. This article describes the recent developments in an inspection system, which uses multiple nondestructive testing techniques to provide the most comprehensive assessment of current tube condition. This is coupled with a sophisticated remaining life assessment software model, which not only predicts the remaining life of each tube in a furnace but can also calculate the effect of changes in future operating conditions on tube ageing. Field experiences and findings are also discussed in the article. © 2010 American Institute of Chemical Engineers Process Saf Prog, 2010
Regulatory initiative for improving industry process safety performance
Authors: P.E. Jay Brabson
Published: September 2010

With the promulgation of regulations in the nineties, targeted to improve process safety for facilities using extremely hazardous substances, there is general agreement that many process safety programs have improved. However, there are still many significant low‐probability high‐consequence accidents, and there is concern that such accidents will continue in the face of issues like cost constraints and the retirement of experienced workers.

This article is about the State of Delaware's Accidental Release Prevention program's efforts to improve industry process safety programs and reduce accidental releases beyond our existing state accidental release prevention regulation, without adding significant burdens to industry. Amending one program's rule (release notification) to help meet the objectives of another's program's rule (accidental release prevention) is not normal procedure. However, we believe this regulatory amendment to be a consistent tool for identifying accidental releases and for holding individual facilities accountable for their process safety performance. © 2010 American Institute of Chemical Engineers Process Saf Prog, 2010
Langasite for microelectromechanical systems
Authors: Ansorge Erik , Schmidt Bertram , Sauerwald Jan , Fritze Holger
Published: September 2010

Piezoelectrically actuated plano‐convex thickness shear mode (TSM) resonators in lanthanum gallium silicate (langasite, LGS, La3Ga5SiO14) were fabricated. For the fabrication of the devices different micromachining technologies were investigated. Finally, a wet etching process and a dry etching process were developed and furthermore graytone‐lithography in combination with photoresist melting has been applied for the final device fabrication. The plano‐convex shape of the resonators is necessary to improve the Q‐factor of the devices. Simulations have been run to show the influence of the spherically contoured surface. The resulting Q‐factor was higher than for simple planar resonators, reaching values of about 25 000. Furthermore, the conductance spectra were significantly improved. The special characteristics of langasite allow working temperatures of up to 1450 °C. At 800 °C Q‐factors of 1700 could be achieved.
Sample size and proportion of Japanese patients in multi‐regional trials
Authors: Ikeda Kimitoshi , Bretz Frank
Published: September 2010

In recent years, multi‐regional trials have received increasing attention by pharmaceutical companies carrying out global drug development programs. In Japan, new drugs are often approved several years after market release in other countries. The recently published guidance on ‘Basic Principles on Global Clinical Trials’ addresses specifically this time lag. A multi‐regional trial has at least two main objectives. First, it is necessary to show a significant benefit in effect of a new drug in the entire population. Second, one needs to demonstrate that the results for a particular region are consistent with those from the entire population. In this paper, we discuss the methods proposed in the Japanese regulatory guidance document and derive closed form expressions for the resulting probabilities, which require the evaluation of multivariate normal or t probabilities. In addition, we propose an alternative method with better operating characteristics than the current approaches. Moreover, we examine the performance of our suggested method by simulating the probability of achieving the objectives and calculating the false‐positive error rate. Copyright © 2010 John Wiley & Sons, Ltd.
An optimal adaptive design to address local regulations in global clinical trials
Authors: Luo Xiaolong , Shih Weichung Joe , Ouyang S. Peter , DeLap Robert J.
Published: September 2010

After multi‐regional clinical trials (MRCTs) have demonstrated overall significant effects, evaluation for a region‐specific effect is often important. Recent guidance (see, e.g. 1) from regulatory authorities regarding evaluation for possible country‐specific effects has led to research on statistical designs that incorporate such evaluations in MRCTs. These statistical designs are intended to use the MRCTs to address the requirements for global registration of a medicinal product. Adding a regional requirement could change the probability for declaring positive effect for the region when there is indeed no treatment difference as well as when there is in fact a true difference within the region. In this paper, we first quantify those probability structures based on the guidance issued by the Ministry of Health, Labour and Welfare (MHLW) of Japan. An adaptive design is proposed to consider those probabilities and to optimize the efficiency for regional objectives. This two‐stage approach incorporates comprehensive global objectives into an integrated study design and may mitigate the need for a separate local bridging study. A procedure is used to optimize region‐specific enrollment based on an objective function. The overall sample size requirement is assessed. We will use simulation analyses to illustrate the performance of the proposed study design. Copyright © 2010 John Wiley & Sons, Ltd.
Encapsulation of the interstellar abundant H3+ in a C60 fullerene
Authors: Ramachandran C. N. , Ruckenstein Eli
Published: September 2010

The possible encapsulation of the interstellar abundant H3+ ion inside a C60 fullerene cage has been examined by using the Hartree‐Fock (HF) and the second order Møller‐Plesset perturbation (MP2) methods both with the 6‐31G** basis set. It was found that H3+ forms various stable endohedral complexes inside the cage. Six configurations have been examined among which four were stable compared with the separated initial species, the dissociated H2 + H+ inside the cage being the most stable. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theory of chemical bonds in metalloenzymes. XV. Local singlet and triplet diradical mechanisms for radical coupling reactions in the oxygen evolution complex
Authors: Yamaguchi Kizashi , Shoji Mitsuo , Saito Toru , Isobe Hiroshi , Nishihara Satomichi , Koizumi Kenichi , Yamada Satoru , Kawakami Takashi , Kitagawa Yasutaka , Yamanaka Shusuke , Okumura Mitsutaka
Published: September 2010

Reaction mechanisms of oxygen evolution in native and artificial photosynthesis II (PSII) systems have been investigated on the theoretical grounds, together with experimental results. First of all, our previous broken‐symmetry (BS) molecular orbitals (MO) calculations are reviewed to elucidate the instability of the dπ‐pπ bond in high‐valent (HV) Mn(X)O systems and the dπ‐pπ‐dπ bond in HV MnOMn systems. The triplet instability of these bonds entails strong or intermediate diradical characters: •Mn(IV)O• and •MnOMn•; the BS MO resulted from strong electron correlation, leading to the concept of electron localizations and local spins. The BS computations have furthermore revealed guiding principles for derivation of selection rules for radical reactions of local spins. As a continuation of these theoretical results, the BS MO interaction diagrams for oxygen‐radical coupling reactions in the oxygen evolution complex (OEC) in the PSII have been depicted to reveal scope and applicability of local singlet diradical (LSD) and local triplet diradical (LTD) mechanisms that have been successfully utilized for theoretical understanding of oxygenation reactions mechanisms by p450 and methane monooxygenase (MMO). The manganese‐oxide cluster models examined are London, Berlin, and Berkeley models of CaMn4O4 and related clusters Mn4O4 and Mn3Ca. The BS MO interaction diagrams have revealed the LSD and/or LTD mechanisms for generation of molecular oxygen in the total low‐, intermediate and high‐spin states of these clusters. The spin alignments are found directly corresponding to the spin‐coupling mechanisms of oxygen‐radical sites in these clusters. The BS UB3LYP calculations of the clusters have been performed to confirm the comprehensive guiding principles for oxygen evolution; charge and spin densities by BS UB3LYP are utilized for elucidation and confirmation of the LSD and LTD mechanisms. Applicability of the proposed selection rules are examined in comparison with a lot of accumulated experimental and theoretical results for oxygen evolution reactions in native and artificial PSII systems. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Identification of Fe‐polycarboxylic complexes by electrospray ionization mass spectrometry and reduction of interferences by ion chromatography/inductively coupled plasma mass spectrometry with an octopole reaction system
Authors: Chen Zu‐Liang , Jin Xiao‐ying , Gan Li
Published: September 2010

Stable complexes are required during the ion chromatographic (IC) separation of Fe‐polycarboxylic acid complexes. Electrospray ionization mass spectrometry (ESI‐MS) was used to identify 1:1 stoichiometric complexes of Fe[HEDTA], Fe[EDTA]1− and Fe[DTPA]2−, and the spectra showed that these Fe complexes were stable in solution. Furthermore, inductively coupled plasma mass spectrometry (ICP‐MS) using an octopole reaction system (ORS) reduced polyatomic ion 40Ar16O+ interference in the detection of 56Fe via the addition of either H2 or He to the ORS, with He at a flow rate 3.5 mL min−1 being the optimum collision gas. Finally, IC/ICP‐MS was used for the separation and detection of Fe complexes with an eluent containing 30 mM (NH4)2HPO4 at pH 8.0, but only Fe[HEDTA], Fe[EDTA]1− and Fe[DTPA]2− were observed within 10 min with reasonable resolution. Detection limits in the range of 10–13 µg L−1 were achieved using He as the collision gas. The proposed method was used for the determination of Fe species in soil solutions. Copyright © 2010 John Wiley & Sons, Ltd.
Using independence to enable parallelism on multicore computers
Authors: Knudsen Svend E.
Published: September 2010

A simple programming abstraction based on the notion of independence is introduced as a means for mapping the independence inherent in an algorithm explicitly into its programmed solution. This enables a compiler and runtime system to exploit the independence and achieve efficient parallelism of execution on multicore processors. The constructs needed to express mutual independence among statements are proposed and their implementation in iOberon, an extension of the Active Oberon programming language, is defined. The programming language extensions, runtime support, and performance measurements are described in detail. We believe that this concept of specifying local disjoint program fragments can be applied to other programming languages. Copyright © 2010 John Wiley & Sons, Ltd.
Monitoring retrogradation in liquorice‐type sweets of different size and hardness
Authors: Díaz Pedro , Ros José María , Bañón Sancho
Published: September 2010

Four different liquorice‐type sweets (LTS) were compared: LS: long stick (253 mm length × 9 mm diameter) + soft recipe (3% w/w acetylated starch; 49/21 w/w sugar/glucose syrup ratio); LH: long stick + hard recipe (6%; 24/42); SS: short stick (115 × 5 mm) + soft recipe; SH: short stick + hard recipe. The length values were used to establish short‐term retrogradation kinetics using Avrami's crystallisation model. The subsequent hardness (48 h) was checked. The retrogradation was faster in the hard recipes. The shortening kinetics could be explained by Avrami's model. The equations Log [‐Ln θ] vs. Log (t) used to calculate the constants of retrogradation (k) and Avrami's coefficients (n) presented R2 values of between 0.98 and 0.99. The mean k.103 (min−n) values were: SH (111.5) > LS (110.9) > LH (97.3) > SS (92.2), while the mean n values were: LH (0.722) > SH (0.680) > SS (0.669) > LS (0.537). Differences in hardness between recipes were only detected (p < 0.05) in long sticks, which showed more pronounced differences in the retrogradation rate. This suggests that the rate of retrogradation could be related with subsequent LTS hardness. Thus, the on‐line control of shortening is proposed for monitoring the rate of retrogradation in LTS.
Effects of cross‐linking on the rheological and thermal properties of sweet potato starch
Authors: Kim Bea‐Young , Yoo Byoungseung
Published: September 2010

Sweet potato starches were modified with three different concentrations of phosphorus oxychloride (POCl3) (0.01, 0.02, and 0.03%, based on dry weight of starch) as a cross‐linking agent. The effects of crosslinking on rheological and thermal properties of sweet potato starch (SPS) pastes were evaluated. Cross‐linking considerably reduced the swelling power, consistency index (K), apparent viscosity (ηa), and yield stress (σoc) values of SPS, which significantly decreased with increase in POCl3 concentration. The gelatinization temperature (Tp) and enthalpy (ΔH) values of the cross‐linked SPS, which were determined using differential scanning calorimetry, were higher than those of native SPS. Storage modulus (G′), loss modulus (G″), and complex viscosity (η*) of the cross‐linked SPS pastes determined using small deformation oscillatory rheometry, were higher than native starch, and they also decreased with increase in POCl3 concentration from 0.01 to 0.03%. The tan δ (ratio of G″/G′) values (0.15–0.19) of the cross‐linked SPS samples were much lower than that (0.37) of the native SPS, indicating that the elastic properties of the SPS pastes were strongly influenced by modifications from cross‐linking. Finally, Cox–Merz plots showed that η* was much higher than ηa for the cross‐linked SPS pastes.
The potential of synthetic thiourea compound to reduce the cytotoxic and genotoxic effects of paraquat in Hordeum vulgare and cultured human lymphocytes
Authors: Gateva Svetla , Jovtchev Gabriele , Stergios Mila , Yonova Petranka
Published: September 2010

This work evaluated the ability of one synthetic compound 1‐(4‐fluorophenylthiocarbamoyl)‐4‐methyl‐piperazine (FTMP), thiourea derivative to reduce cytoxic and genotoxic effects of free radical inducer paraquat (PQ) in two different test systems Hordeum vulgare and human lymphocytes in vitro. The mitotic index was used as a marker for cytotoxicity. To indicate genotoxicity, chromosome aberrations test and micronucleus induction test were used. FTMP manifested a weak genotoxic effect in both test systems. Clear evidence was obtained that conditioning treatment with FTMP (10−6, 5 × 10−6, and 10−5 mol/l) could decrease chromosome aberrations and micronuclei induced by PQ in both test systems. “Aberration hot spots” in heterochromatin containing segments were reduced. The present data show that the thiourea synthetic compound FTMP provides genome protection against the harmful action of oxidative stress inductor PQ. Human lymphocytes were found to be more sensitive to the cytotoxic and clastogenic effects of FTMP conditioning treatment than Hordeum vulgare. Revealing the protective action of newly synthesized compounds could contribute to the improvement of our present knowledge of the mechanisms of mutagenesis and antimutagenesis. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
Fundamental limits and improved algorithms for linear least‐squares wireless position estimation
Authors: Guvenc Ismail , Gezici Sinan , Sahinoglu Zafer
Published: September 2010

In this paper, theoretical lower bounds on performance of linear least‐squares (LLS) position estimators are obtained, and performance differences between LLS and nonlinear least‐squares (NLS) position estimators are quantified. In addition, two techniques are proposed in order to improve the performance of the LLS approach. First, a reference selection algorithm is proposed to optimally select the measurement that is used for linearizing the other measurements in an LLS estimator. Then, a maximum likelihood approach is proposed, which takes correlations between different measurements into account in order to reduce average position estimation errors. Simulations are performed to evaluate the theoretical limits and to compare performance of various LLS estimators. Copyright © 2010 John Wiley & Sons, Ltd.
Providing and findingk‐road‐coverage efficiently in wireless sensor networks
Authors: Mao Xufei , Xu Xiaohua , Tang ShaoJie , Li Xiang‐Yang
Published: September 2010

In this paper, we studyk‐road‐coverage problems in wireless sensor networks (WSNs). Assume there is a 2‐dimensional area Ω with a given road map = (V,E) whereEcontains all road segments andVconsists of all intersection points on Ω. The first question we study is about ‘sensor deployment’,i.e., how to deploy a minimum number of sensor nodes on Ω such that each path (each road segment) onisk‐covered when all sensor nodes have the same sensing range. When sensors can only be deployed in a set of discrete locations, we propose an efficient method with the approximation ratio 6 + ϵ for the special case wherek = 1 and O(k) generally. If sensors can be deployed in arbitrary locations, we propose an efficient method with the approximation ratio 24 + ϵ whenk = 1 and O(k) generally. The second question we study is about ‘path query’,i.e., how to find thek‐covered path ork‐support path connecting any given source/destination pair of points on the road map. Basically, given any source/destination pair of pointsSandD, we present two algorithms which can efficiently find ak‐covered path connectingSandDand ak‐supported path connectingSandD, respectively. Copyright © 2010 John Wiley & Sons, Ltd.
Children's episodic memory
Authors: Ghetti Simona , Lee Joshua
Published: September 2010

Episodic memory develops during childhood and adolescence. This trajectory depends on several underlying processes. In this article, we first discuss the development of the basic binding processes (e.g., the processes by which elements are bound together to form a memory episode) and control processes (e.g., reasoning and metamemory processes) involved in episodic remembering. Then, we discuss the role of these processes in false‐memory formation. In the subsequent sections, we examine the neural substrates of the development of episodic memory. Finally, we discuss atypical development of episodic memory. As we proceed through the article, we suggest potential avenues for future research. WIREs Cogni Sci 2011 2 365–373 DOI: 10.1002/wcs.114

This article is categorized under:

Psychology > Development and Aging
The nucleolus: structure/function relationship in RNA metabolism
Authors: Hernandez‐Verdun Danièle , Roussel Pascal , Thiry Marc , Sirri Valentina , Lafontaine Denis L. J.
Published: September 2010

The nucleolus is the ribosome factory of the cells. This is the nuclear domain where ribosomal RNAs are synthesized, processed, and assembled with ribosomal proteins. Here we describe the classical tripartite organization of the nucleolus in mammals, reflecting ribosomal gene transcription and pre‐ribosomal RNA (pre‐rRNA) processing efficiency: fibrillar center, dense fibrillar component, and granular component. We review the nucleolar organization across evolution from the bipartite organization in yeast to the tripartite organization in humans. We discuss the basic principles of nucleolar assembly and nucleolar structure/function relationship in RNA metabolism. The control of nucleolar assembly is presented as well as the role of pre‐existing machineries and pre‐rRNAs inherited from the previous cell cycle. In addition, nucleoli carry many essential extra ribosomal functions and are closely linked to cellular homeostasis and human health. The last part of this review presents recent advances in nucleolar dysfunctions in human pathology such as cancer and virus infections that modify the nucleolar organization. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry

Translation > Ribosome Biogenesis

RNA in Disease and Development > RNA in Disease
Protein–protein interaction networks and subnetworks in the biology of disease
Authors: Nibbe Rod K. , Chowdhury Salim A. , Koyutürk Mehmet , Ewing Rob , Chance Mark R.
Published: September 2010

The main goal of systems medicine is to provide predictive models of the patho‐physiology of complex diseases as well as define healthy states. The reason is clear—we hope accurate models will ultimately lead to more specific and sensitive markers of disease that will help clinicians better stratify their patient populations and optimize treatment plans. In addition, we expect that these models will define novel targets for combating disease. However, for many complex diseases, particularly at the clinical level, it is becoming increasingly clear that one or a few genomic variations alone (e.g., simple models) cannot adequately explain the multiple phenotypes related to disease states, or the variable risks that attend disease progression. We suggest that models that account for the activities of many interacting proteins will explain a wider range of variability inherent in these phenotypes. These models, which encompass protein interaction networks dysregulated for specific diseases and specific patient sub‐populations, will be constructed by integrating protein interaction data with multiple types of other relevant cellular information. Protein interaction databases are thus playing an increasingly important role in systems biology approaches to the study of disease. They present us with a static, but highly functional view of the cellular state, and thus give us a better understanding of not only the normal phenotype, but also the overall disease phenotype at the level of the whole organism when certain interactions become dysregulated. WIREs Syst Biol Med 2011 3 357–367 DOI: 10.1002/wsbm.121

This article is categorized under:

Biological Mechanisms > Regulatory Biology
Addressing the Challenge of Community Reentry Among Released Inmates with Serious Mental Illness
Authors: Baillargeon Jacques , Hoge Stephen K. , Penn Joseph V.
Published: September 2010

The purpose of the paper is to discuss the formidable challenges to community reentry and reintegration faced by U.S. prison inmates with serious mental illness and to describe various strategies for improving transitional services for these individuals. We review epidemiologic data supporting the high prevalence of severe mental illness in U.S. prisons as well as the historical factors underlying the criminalization of the mentally ill. The importance and challenges of providing adequate psychiatric care for mentally ill prisoners during their incarceration are discussed. We also review the numerous psychosocial and economic challenges confronting these individuals upon their release from prison, such as unemployment and vulnerability to homelessness, as well as specific barriers they may encounter in attempting to access community‐based mental health services. We follow with a discussion of some of the more promising strategies for improving the transition of the mentally ill from prison to the community. In the final sections, we review the evidence for a relationship between serious mental illness and recidivism and briefly discuss emerging alternatives to incarceration of the mentally ill.
Poverty Among Adults with Disabilities: Barriers to Promoting Asset Accumulation in Individual Development Accounts
Authors: Soffer Michal , McDonald Katherine E. , Blanck Peter
Published: September 2010

Adults with disabilities disproportionally experience poverty. We examine one novel strategy to promote economic well‐being among adults with disabilities living in or near poverty, namely Individual Development Accounts (IDAs). IDAs are designed to help individuals save money and subsequently accumulate assets. Although adults with disabilities account for the majority of IDA participants, scant attention has been paid to their IDA saving performance. We describe the significance of accumulating assets, particularly as it relates to adults with disabilities. We then map the nature of IDA programs and analyze barriers to participation in IDAs and asset accumulation related to conflicting federal policies and a lack of sensitivity to disability‐specific needs. We conclude by offering policy recommendations from our analysis, including the need to eliminate the means‐tests used in welfare policies, de‐linking participation in IDAs from employment status, and involving people with disabilities in designing and evaluating asset accumulation policies and programs.
StoryToCode: a new model for specification of convergent interactive digital TV applications
Authors: Marques Neto Manoel C. , Santos Celso A. S.
Published: September 2010

This paper presents a model, called the StoryToCode, which allows designing iTV programs focusing on using software components. First, StoryToCode allows transforming a storyboard into an abstract description of an element set. After this, this model transforms these elements into a specific programming language source code. In StoryToCode a software component is treated as a special element that can be reused in other contexts (web, mobile, and so on). StoryToCode is based on Model Driven Architecture (MDA) and allows designing and implementing applications, with context free, considering iTV program specific characteristics.
Adolescent summer care arrangements and risk for obesity the following school year
Authors: Mahoney Joseph L.
Published: September 2010

This longitudinal study identified common summer care arrangements for adolescents and examined whether those arrangements predicted risk for obesity (Body Mass Index (BMI) ≥ 85th percentile for age and gender) the following school year. Participants were a nationally representative sample of 1766 adolescents ages 10–18 from the Panel Study of Income Dynamics–Child Development Supplement. Results showed that, beyond measures of BMI taken before the summer and several demographic aspects known to predict obesity, youth whose summer arrangements involved regular participation in organized activities (e.g., sports) showed significantly lower risk for obesity than other youth. This was most evident during early adolescence. Youth whose regular summer arrangement was predominated by parent care without organized activity participation showed the greatest risk for obesity.