bluuebunny/crossref_metadata_2025 huggingface dataset:
Tomato CYP74C3 is a Multifunctional Enzyme not only Synthesizing Allene Oxide but also Catalyzing its Hydrolysis and Cyclization
Authors: Grechkin Alexander N. , Mukhtarova Lucia S. , Latypova Larisa R. , Gogolev Yuri , Toporkova Yana Y. , Hamberg Mats
Published: September 2008

The mechanism of the recombinant tomato allene oxide synthase (LeAOS3, CYP74C3) was studied. Incubations of linoleic acid (9S)‐hydroperoxide with dilute suspensions of LeAOS3 (10–20 s, 0 °C) yield mostly the expected allene oxide (12Z)‐9,10‐epoxy‐10,12‐octadecadienoic acid (9,10‐EOD), which was detected as its methanol‐trapping product. In contrast, the relative yield of 9,10‐EOD progressively decreased when the incubations were performed with fourfold, tenfold, or 80‐fold larger amounts of LeAOS3, while α‐ketol and the cyclopentenone rac‐cis‐10‐oxo‐11‐phytoenoic acid (10‐oxo‐PEA) became the predominant products. Both the α‐ketol and 10‐oxo‐PEA were also produced when LeAOS3 was exposed to preformed 9,10‐EOD, which was generated by maize allene oxide synthase (CYP74A). LeAOS3 also converted linoleic acid (13S)‐hydroperoxide into the corresponding allene oxide, but with about tenfold lower yield of cyclopentenone. The results indicate that in contrast to the ordinary allene oxide synthases (CYP74A subfamily), LeAOS3 (CYP74C subfamily) is a multifunctional enzyme, catalyzing not only the synthesis, but also the hydrolysis and cyclization of allene oxide.
Multifunctional Enzymes in Oxylipin Metabolism
Authors: Wasternack Claus , Feussner Ivo
Published: September 2008

Fingers in lots of pies: For the first time a member of the CYP74 enzyme subfamily (9‐AOS) from tomato has been shown by chemical and analytical approaches to catalyze multiple reactions. These multifunctional properties of 9‐AOS from the oxylipin‐forming lipoxygenase (LOX) pathway raise several new questions on lipid‐derived signaling.
Nucleation and Growth of BaFxCl2−x Nanorods
Authors: Xie Ting , Li Shuai , Wang Wenbei , Peng Qing , Li Yadong
Published: September 2008

Different ratios and sizes of Ba2F3Cl (BaFxCl2−x, x=1.5) nanorods and nanowires and orthorhombic BaF2 (BaFxCl2−x, x=2) nanorods were prepared by using a liquid–solid–solution approach at 160∼180 °C. The processes and results of the experiments conducted to prepare monodisperse Ba2F3Cl nanorods and nanowires showed that the specific surface area increased as the initial concentrations were multiplied. Based on this fact, a mechanism for the nucleation and growth processes of these nanocrystals that have a variety of enlarged sizes was substantiated in view of the surface chemical thermodynamics (SCT). In this SCT mechanism, the specific surface energy takes into account both the surfactant oleic acid and the nanocrystal surface, and is dominated by the chemical potential of the adsorbate.
Zipped‐Up Chain‐Type Coordination Polymers: Unsymmetrical Amide‐Containing Ligands Inducing β‐Sheet or Helical Structures
Authors: Uemura Kazuhiro , Kumamoto Yuki , Kitagawa Susumu
Published: September 2008

The crystal structures of thirteen AgI coordination polymers involving py‐CONH‐(CH2)n‐py (py=pyridine; n=0, 1) derivatives were determined by means of single‐crystal X‐ray analyses. All of the compounds form one‐dimensional chains composed of AgI atoms and bridging ligands with formulas {[Ag(py‐CONH‐(CH2)n‐py)][X]}n (X=PF6−, ClO4−, BF4−, and NO3− with solvent molecules). The unsymmetrical coordination environments around AgI atoms induce direction in the chains, that is, ‐[NH‐(CH2)n‐py‐Ag‐py‐CO]‐, which resembles the alignment of amino acid chains in proteins. In compounds {[Ag(4‐pia)][X]}n (1⊃X; 4‐pia=N‐(4‐pyridyl)isonicotinamide; X=PF6−, ClO4−, BF4−, and NO3−), {[Ag(4‐pmia)][X]}n (2⊃X; 4‐pmia=N‐(pyridin‐4‐ylmethyl)isonicotinamide; X=PF6−, ClO4−⋅H2O, and NO3−⋅H2O), and {[Ag(3‐pmia)][X]}n (3⊃X; 3‐pmia=N‐(pyridin‐3‐ylmethyl)isonicotinamide; X=PF6−, ClO4−, BF4−, and NO3−⋅H2O), each chain is aligned parallel to neighboring chains, but adjacent chains run in the opposite direction. Particularly in {[Ag(3‐pmia)][PF6]}n (3⊃PF6−), {[Ag(3‐pmia)][ClO4]}n (3⊃ClO4−), and {[Ag(3‐pmia)][BF4]}n (3⊃BF4−), amide moieties of 3‐pmia ligands are complementarily hydrogen bonded to amide moieties in neighboring chains, as in the β‐sheet motif in proteins. On the other hand, in {[Ag(4‐pmna)][PF6]⋅MeOH}n (4‐pmna=N‐(pyridin‐4‐ylmethyl)nicotinamide), all chains in the crystal form left‐handed (4 a⊃PF6−⋅MeOH) and right‐handed (4 b⊃PF6−⋅MeOH) helical structures with a helical pitch of 28 Å. Heterogeneous anion exchanges proceed reversibly in 2, but not in 3, which provides information about the thermal stabilities of the crystals.
Expanding Sapphyrin: Towards Selective Phosphate Binding
Authors: Katayev Evgeny A. , Boev Nikolay V. , Myshkovskaya Ekaterina , Khrustalev Victor N. , Ustynyuk Yu. A.
Published: September 2008

The anion‐templated syntheses and binding properties of novel macrocyclic oligopyrrole receptors in which pyrrole rings are linked through amide or imine bonds are described. The efficient synthesis was accomplished by anion‐templated [1+1] Schiff‐base condensation and acylation macrocyclization reactions. Free receptors and their host–guest complexes with hydrochloric acid, acetic acid, tetrabutylammonium chloride, and hydrogen sulfate were analyzed by single‐crystal X‐ray diffraction analysis. Stability constants with different tetrabutylammonium salts of inorganic acids were determined by standard 1H NMR and UV/Vis titration techniques in [D6]DMSO/0.5 % water solution. According to the titration data, receptors containing three pyrrole rings (10 and 12) exhibit high affinity (log Ka=5–7) for bifluoride, acetate, and dihydrogen phosphate, and interact weakly with chloride and hydrogen sulfate. The amido‐bipyrrole receptors 11 and 13 with four pyrrole rings exhibit 104‐ and 102‐fold selectivity for dihydrogen phosphate, respectively, as inferred from competitive titrations in the presence of tetrabutylammonium acetate.
Electrochemical Functionalization of Carbon Surfaces by Aromatic Azide or Alkyne Molecules: A Versatile Platform for Click Chemistry
Authors: Evrard David , Lambert François , Policar Clotilde , Balland Véronique , Limoges Benoît
Published: September 2008

The electrochemical reduction of phenylazide or phenylacetylene diazonium salts leads to the grafting of azido or ethynyl groups onto the surface of carbon electrodes. In the presence of copper(I) catalyst, these azide‐ or alkyne‐modified surfaces react efficiently and rapidly with compounds bearing an acetylene or azide function, thus forming a covalent 1,2,3‐triazole linkage by means of click chemistry. This was illustrated with the surface coupling of ferrocenes functionalized with an ethynyl or azido group and the biomolecule biotin terminated by an acetylene group.
Photo‐, Solvent‐, and Ion‐Controlled Multichromism of Imidazolium‐Substituted Diarylethenes
Authors: Nakashima Takuya , Miyamura Kentaro , Sakai Toshiyuki , Kawai Tsuyoshi
Published: September 2008

Seeing red: Imidazolium‐substituted diarylethenes show solvent‐ and ion‐controlled chromisms in addition to reversible photochromic reactions. The shift of equilibrium between two closed‐ring isomers with different π‐conjugation length by interaction with nucleophilic species is responsible for the multichromic property (see scheme).

magnified image

Cationic diarylethenes with an imidazolium ring are synthesized for the first time. The imidazolium cationic moiety is connected directly to the ethene unit as one of the aryl units that take part in the photoinduced pericyclization reaction. The imidazolium‐substituted diarylethenes undergo reversible photochromic reactions in a variety of organic media, including ionic liquids, even though they have a delocalized cationic charge in one of the five‐membered aromatic rings. The closed‐ring isomer shows solvatochromism depending on the solvent donor numbers. Addition of some tetraalkylammonium salts, such as tetrabutyl ammonium nitrate, into the colored organic solution of diarylethene also causes a color change, indicating its ionochromic property. These solvato‐ and ionochromic properties are considered in connection with the shift of chemical equilibrium between the closed‐ring isomers, one with an extended π‐conjugation system and one with limited π‐conjugation due to the strong interaction with solvent molecules and anions with high donor number.
Self‐Assembly of Oligo(para‐phenylenevinylene)s through Arene—Perfluoroarene Interactions: π Gels with Longitudinally Controlled Fiber Growth and Supramolecular Exciplex‐Mediated Enhanced Emission
Authors: Babu Sukumaran S. , Praveen Vakayil K. , Prasanthkumar Seelam , Ajayaghosh Ayyappanpillai
Published: September 2008

The arene–perfluoroarene (ArH–ArF) interaction, which has been extensively studied in the field of solid‐state chemistry, is exploited in the hierarchical self‐assembly of oligo(para‐phenylenevinylene)s (OPVs) with controlled longitudinal fiber growth that leads to gelation. The size of the self‐assembled fibers of a pentafluorophenyl‐functionalized OPV 5 could be controlled through C‐F⋅⋅⋅HC hydrogen bonding and π stacking. The ability of fluoroaromatic compounds to form excited‐state complexes with aromatic amines has been utilized to form a supramolecular exciplex, exclusively in the gel state, that exhibits enhanced emission. Thus, the commonly encountered fluorescence quenching during the self‐assembly of OPVs could be considerably prevented by exciplex formation with N,N‐dimethylaniline (DMA), which only occurred for the fluorinated OPV and not for the non‐fluorinated analogue 4. In the former case, a threefold enhancement in the emission intensity could be observed in the gel state, whereas no change in emission occurred in solution. Thus, the major limitations of spontaneous fiber growth and fluorescence self‐quenching encountered in the self‐assembly of OPVs could be controlled to a great extent by using the versatile ArH–ArF interaction.
Clinical Implications of Elevated Serum Interleukin‐6, Soluble CD40 Ligand, Metalloproteinase‐9, and Tissue Inhibitor of Metalloproteinase‐1 in Patients with Acute ST‐segment Elevation Myocardial Infarction
Authors: Tan Jing , Hua Qi , Gao Jing , Fan Zhen Xing
Published: September 2008

Background

Atherosclerosis is widely accepted as a chronic inflammatory disease. Research paid much attention to sensitive specific serum biomarkers for vulnerable plaques. The markers not only serve as diagnostic tools for the identification of patients with acute coronary syndrome (ACS), but also help us to identify high‐risk patients. However, the existing data are limited and have been conflicting.

Hypothesis

Circulating interleukin‐6 (IL‐6), soluble CD40 ligand (sCD40L), metalloproteinase‐9 (MMP‐9), and tissue inhibitor of metalloproteinase‐1 (TIMP‐1) might correlate with the onset and the cardiac mortality of patients with ST‐segment elevation myocardial infarction (STEMI).

Methods

Serum levels of IL‐6, sCD40L, MMP‐9, and TIMP‐1 were measured by sandwich enzyme‐linked immunosorbent assay (ELISA) in 263 patients with STEMI and 262 age‐ and gender‐matched control subjects without coronary artery disease (CAD). The patients with STEMI were then followed prospectively for 24 mo for the occurrence of cardiac mortality.

Results

Compared with the control subjects, patients with STEMI exhibited higher levels of IL‐6 (p < 0.001), sCD40L (p < 0.001), MMP‐9 (p < 0.001), TIMP‐1 (p = 0.045), and MMP‐9/TIMP‐1 ratio (p = 0.007). Significant and positive correlations between MMP‐9 and TIMP‐1 (r = 0.610, p≤0.001]), IL‐6 and creatine kinase (CK) (r = 0.159, p = 0.022), and IL‐6 and Troponin‐I (TnI) (r = 0.141, p = 0.042) were observed by Spearman's correlations analysis. Logistic regression analysis revealed that IL‐6 significantly and independently correlated with the occurrence of STEMI, and IL‐6 was an independent predictor for cardiac mortality during a 24‐mo follow‐up in patients with STEMI.

Conclusion

The present study indicates that elevated admission level of IL‐6, but not of sCD40L, MMP‐9, or TIMP‐1, might indicate the onset of STEMI, and could provide prognostic value for future cardiac mortality within 2 y in patients with STEMI. Copyright © 2008 Wiley Periodicals, Inc.
Myocardial and Aortic Stiffening in the Early Course of Primary Aldosteronism
Authors: Tsioufis Costas , Tsiachris Dimitrios , Dimitriadis Kyriakos , Stougiannos Pavlos , Missovoulos Platonas , Kakkavas Apostolis , Stefanadis Christodoulos , Kallikazaros Ioannis
Published: September 2008

Background

Primary aldosteronism (PA) has been experimentally and clinically linked to myocardial and vascular fibrosis, and it has been further associated with left ventricular (LV) structural adaptations.

Hypothesis

Functional cardiovascular adaptations in hypertensive patients with PA precede structural alterations in the early stages of the disease.

Methods

We studied 17 hypertensive subjects with a recent diagnosis of PA (10 male patients, aged approximately 55 y, with office blood pressure [BP] of 137/88 mm Hg), and 30 essential hypertensives matched for age, sex, office BP levels, treatment status, and LV mass index (LVMI). Apart from standard 2‐Dimensional (2‐D) and conventional Doppler parameters, tissue Doppler imaging (TDI) methodology was used to assess LV diastolic function; averaging early and late diastolic mitral annular peak velocities (Emav/, Amav, Emav/Amav ratio) from 4 separate sites of measurement (septal, lateral, anterior, and inferior walls). Aortic stiffness was evaluated by means of carotid‐femoral pulse wave velocity (cf‐PWV) measurements.

Results

Although transmitral E/A ratio was similar in both groups (0.95 ± 0.26 versus 0.98 ± 0.24, ± p 0.66), hypertensive subjects with PA compared with essential hypertensives are characterized by significantly higher relative wall thickness (0.50 ± 0.07 versus 0.41 ± 0.06, p ≤ 0.001), decreased values of Emav (7 ± 1.7 versus 8.1 ± 1.8 cm/s, p= 0.048), and Emav/Amav ratio (0.63 ± 0.16 versus 0.77 ± 0.17, p = 0.015). The higher PWV in the PA population failed to reach statistical significance (8.5 ± 1.6 versus 7.9 ± 0.9 msec, p = 0.19).

Conclusion

Our study demonstrates altered LV geometry and TDI‐revealed diastolic dysfunction in hypertensives with PA compared with demographically‐ and LVMI‐matched essential hypertensives. Furthermore, the increased aortic stiffening in PA patients failed to reach statistical significance. Copyright © 2008 Wiley Periodicals, Inc.
Endogenous B‐type Natriuretic Peptide: A Limb of the Regulatory Response to Acutely Decompensated Heart Failure
Authors: Hobbs Robert E. , Mills Roger M.
Published: September 2008

Acutely decompensated heart failure (ADHF) represents an episodic failure of cardiorenal homeostasis that may resolve with upregulation of natriuretic peptides, bradykinin, and certain prostacyclins. B‐type natriuretic peptide (BNP) has multiple favorable effects, including vasodilation, diuresis, natriuresis, and inhibition of vascular endothelial proliferation and cardiac fibrosis. By antagonizing the effects of activation of the renin‐angiotensin‐aldosterone system (RAAS) and the sympathetic nervous system in volume overload, the endogenous BNP response may help rescue patients from episodic ADHF. Although knowledge of BNP physiology is expanding, we still have limited understanding of the heterogeneity of proBNP‐derived molecules, including active 32 amino acid BNP and less active junk BNP forms. Emerging evidence suggests that in ADHF, the endogenous BNP response is overwhelmed by neurohormonal activation. This relative BNP deficiency may also be accompanied by physiologic resistance to BNP. Additionally, abnormalities of BNP production may result in a lower proportion of active BNP relative to less active forms that may also be detected by point‐of‐care tests. Improved detection of the various BNP species may clarify these concepts and facilitate improved clinical management of ADHF. Copyright © 2008 Wiley Periodicals, Inc.
Reassessing the Cardiovascular Risks and Benefits of Thiazolidinediones
Authors: Zinn Andrew , Felson Sabrina , Fisher Edward , Schwartzbard Arthur
Published: September 2008

This article is designed for the general cardiologist, endocrinologist, and internist caring for patients with diabetes and coronary artery disease. Despite the burden of coronary disease in diabetics, little is known about the impact of commonly used oral hypoglycemic agents on cardiovascular outcomes. As the untoward effects of insulin resistance (IR) are increasingly recognized, there is interest in targeting this defect. Insulin resistance contributes to dyslipidemia, hypertension, inflammation, hypercoagulability, and endothelial dysfunction. The aggregate impact of this process is progression of systemic atherosclerosis and an increased risk of adverse cardiovascular outcomes. As such, much attention has been paid to the peroxisome‐proliferator‐activated receptor gamma (PPARg) agonists rosiglitazone and pioglitazone (thiazolidinediones [TZDs]). Many studies have demonstrated a beneficial effect on the atherosclerotic process; specifically, these agents have been shown to reduce markers of inflammation, retard progression of carotid intimal thickness, prevent restenosis after coronary stenting, and prevent cardiovascular death and myocardial infarction in 1 large trial. Such benefits come at the risk of fluid retention and heart failure (HF) exacerbation, and the net effect on plasma lipids is still poorly understood. Thus, the aggregate risk‐benefit ratio is poorly defined. A recent meta‐analysis has raised significant concerns regarding the overall cardiovascular safety of 1 particular PPARg agonist (rosiglitazone), prompting international debate and regulatory changes. This review scrutinizes the clinical evidence regarding the cardiovascular risks and benefits of PPARg agonists. Future studies of PPARg agonists, and other emerging drugs that treat IR and diabetes, must be designed to look at cardiovascular outcomes. Copyright © 2008 Wiley Periodicals, Inc.
Blood Pressure Measurement: Sitting and Standing?
Authors: Richard Conti C.
Published: September 2008

Prior to discussing some thoughts about positional changes in blood pressure, I'd like to comment on the me‐ asurement of blood pressure.

It is rare for a medical student, a resident‐in‐training, a cardiovascular fellow‐in‐training, or even a practicing or academic cardiologist to take the patient's blood pressure. I would even go so far as to say that it is uncommon for a registered nurse to measure blood pressure. Copyright © 2008 Wiley Periodicals, Inc.
Role of Biofuels in a Sustainable Environment – A Technical Study
Authors: Rao G. Lakshmi Narayana , Saravanan Subramani
Published: September 2008

Creating a clean and safe environment has always been a challenge for researchers throughout the world. The use of fossil fuel has been a deterrent in attaining this objective. Therefore, attention has been focused on biofuels to suit this objective. In recent years, efforts have been directed towards environmentally friendly sources of alternate fuels for diesel engines. This paper compares the performance and emission characteristics of biofuels with mineral no. 2 diesel oil. A direct injection diesel engine coupled with an eddy current dynamometer is used for this investigation. Rice bran oil and neem oil are considered as biofuels for this work since they are renewable in nature. Rice bran oil is extracted from rice bran, which is a by‐product of the rice milling process. Neem oil is derived from neem seed, which are abundantly available in India. In addition to these oils, their blends with diesel are also used to test their ability for reducing emissions. This study indicated that, among the two biofuels, the rice bran oil and its blend shows better results with respect to emissions than the neem oil and its blend. The results for the rice bran oil and its blend are slightly better than those of diesel and superior to pure neem oil and its blend. The unburned hydrocarbon (UBHC) emissions of biofuels and their blends are lower when compared with diesel. Biofuels show lower nitrogen oxide (NOx) emissions when compared with diesel and biofuel blends. It was observed that the smoke intensities of all the fuels tested are similar up to 50% loads. At higher loads, biofuels and their blends showed slightly higher smoke intensities than diesel.
Reduction in Exhaust Gas Temperature of Biodiesel Fueled Engine by Exhaust Gas Recirculation
Authors: Ramadhas Arumugam Sakunthalai , Muraleedharan Chandrasekaran , Jayaraj Simon
Published: September 2008

Biodiesel is a renewable alternative fuel that can be used as substitute for mineral diesel. The use of biodiesel in diesel engines reduces all of the exhaust emissions expect NOx. The higher temperature in the combustion chamber increases the NOx emissions. The recirculation of a small percentage of cooled exhaust gases into the combustion chamber through the intake manifold reduces the in‐cylinder temperature. Moreover, the cooling of exhaust gases before mixing with fresh air introduced to the engine does not affect its volumetric efficiency but it absorbs the heat of combustion. This leads to a reduction in NOx emissions and improves the engine brake thermal efficiency. This paper describes the investigation of the performance and emission characteristics of a biodiesel‐fueled, naturally aspirated, single cylinder diesel engine with cooled exhaust gas recirculation.
Numerical methods for energy flux of temperature diffusion equation on unstructured meshes
Authors: Lv Guixia , Shen Longjun , Shen Zhijun
Published: September 2008

In this paper, a new approach for approximating energy flux of temperature diffusion equation on unstructured meshes is presented, which is based on different formulae of the finite point method with different accuracies. In addition, a new numerical formula for computing cell nodal temperature is given. Numerical experiments show the good performance and accuracy of our methods. Copyright © 2008 John Wiley & Sons, Ltd.
Detecting particle swarm optimization
Authors: Zhang Ying‐Nan , Teng Hong‐Fei
Published: September 2008

Here, we propose a detecting particle swarm optimization (DPSO). In DPSO, we define several detecting particles that are randomly selected from the population. The detecting particles use the newly proposed velocity formula to search the adjacent domains of a settled position in approximate spiral trajectories. In addition, we define the particles that use the canonical velocity updating formula as common particles. In each iteration, the common particles use the canonical velocity updating formula to update their velocities and positions, and then the detecting particles do search in approximate spiral trajectories created by the new velocity updating formula in order to find better solutions. As a whole, the detecting particles and common particles would do the high‐performance search. DPSO implements the common particles' swarm search behavior and the detecting particles' individual search behavior, thereby trying to improve PSO's performance on swarm diversity, the ability of quick convergence and jumping out the local optimum. The experimental results from several benchmark functions demonstrate good performance of DPSO. Copyright © 2008 John Wiley & Sons, Ltd.
Intelligent scheduling and replication: a synergistic approach
Authors: Elghirani Ali , Subrata Riky , Zomaya Albert Y.
Published: September 2008

In large‐scale data‐intensive applications data play a pivotal role in the execution of these applications, and data transfer is a primary cause of job execution delay. In environments such as the data grids where execution of jobs that require large amounts of data is undertaken, a smart collaborative environment between the scheduling and data management services to achieve a synergistic effect on the performance of the grid becomes essential. This paper presents an intelligent data grid framework where job scheduling and data and replica management are coupled to provide an integrated environment for efficient access to data and job scheduling. The data management service predicts and estimates the appropriate locations of replica and proactively replicates the data sets in these locations while the intelligent tabu‐search‐based scheduler incorporating information about the data sets dispatches the jobs to the sites expected to facilitate minimum job execution time and better overall system utilization. Evaluation of the framework shows significant improvement in the performance of the grid and job execution time. Copyright © 2008 John Wiley & Sons, Ltd.
Optimizing description logic reasoning for the large‐scale semantic repositories
Authors: Babík Marian , Hluchý Ladislav
Published: September 2008

The semantic Grid is a recent initiative to expose semantically rich information associated with Grid resources to build more intelligent Grid services. Recently, several projects have embraced this vision and there are several successful applications that combine the strengths of the Grid and of semantic technologies. However, semantic Grid still lacks a technology, which would provide the needed scalability and integration with existing infrastructure. In this paper we present our on‐going work on a semantic Grid repository, which is capable of addressing complex schemas and answer queries over ontologies with a large number of instances. We present the details of our approach and describe the underlying architecture of the system. We conclude with a performance evaluation, which compares the current state‐of‐the‐art reasoners with our system. Copyright © 2008 John Wiley & Sons, Ltd.
On the connectivity of Bluetooth‐basedad hocnetworks
Authors: Crescenzi P. , Nocentini C. , Pietracaprina A. , Pucci G.
Published: September 2008

We study the connectivity properties of a family of random graphs that closely model the Bluetooth's device discovery process, where each device tries to connect to other devices within its visibility range in order to establish reliable communication channels yielding a connected topology. Specifically, we provide both analytical and experimental evidence that when the visibility range of each node (i.e. device) is limited to a vanishing function ofn, the total number of nodes in the system, full connectivity can still be achieved with high probability by letting each node connect only to a ‘small’ number of visible neighbors. Our results extend previous studies, where connectivity properties were analyzed only for the case of a constant visibility range, and provide evidence that Bluetooth can indeed be used for establishing largead hocnetworks. Copyright © 2008 John Wiley & Sons, Ltd.
Cooperation in multi‐organization scheduling
Authors: Pascual Fanny , Rzadca Krzysztof , Trystram Denis
Published: September 2008

The distributed nature of the grid results in the problem of scheduling parallel jobs produced by several independent organizations that have partial control over the system. We consider systems in which each organization owns a cluster of processors. Each organization wants its tasks to be completed as soon as possible. In this paper, we model an off‐line system consisting ofNidentical clusters ofmprocessors. We show that it is always possible to produce a collaborative solution that respects participants' selfish goals, at the same time improving the global performance of the system. We propose an algorithm (called MOLBA) with a guaranteed worst‐case performance ratio on the global makespan, equal to 4. Next, we show that a better bound (equal to 3) can be obtained in a specific case when the last completed job requires at mostm/2processors. Then, we derive another algorithm (called ILBA) that in practice improves the proposed, guaranteed solution by further balancing the schedules. Finally, by an extensive evaluation by simulation, we show that the algorithms are efficient on typical instances. Copyright © 2008 John Wiley & Sons, Ltd.
Non‐Resonant z‐Scan Characterization of the Third‐Order Nonlinear Optical Properties of Conjugated Poly(thiophene azines)
Authors: Faccinetto Alessandro , Mazzucato Simone , Pedron Danilo , Bozio Renato , Destri Silvia , Porzio William
Published: September 2008

The nonlinear optical properties of a functionalized poly(thiophene azine), namely, poly(3,4‐didodecylthiophene azine), PAZ, at the optical telecommunication wavelength of 1550 nm are investigated by means of the closed‐aperture z‐scan technique in both thin films and solutions. Values of χ(3)=(2.4±0.4)×10−13 esu, n2=(4.0±0.7)×10−15 cm2 W−1, and γ=(4.5±0.7)×10−34 esu are estimated for the third‐order (Kerr) susceptibility, the intensity‐dependent refractive index, and the molecular second hyperpolarizability of solution samples, respectively. A very small dependence on the polymer chain length is found. Markedly higher values of (4.4±1.1)×10−11 esu, (6.6±1.0)×10−13 cm2 W−1, and (5.0±0.8)×10−33 esu are measured for the corresponding quantities in thick (up to 20 μm) polymer films cast on quartz plates. The enhancement of the NLO responses on going from solution to solid samples is attributed to a partially ordered structure and to the presence of interchain interactions leading to greater π‐electron delocalization in the cast polymer films. The results are compared with those previously obtained by using third‐harmonic generation (THG), taking into account that those data were measured under conditions of three‐photon resonance, whereas our z‐scan measurements are fully off‐resonance.
Optimizing peptide matrices for identifying T‐cell antigens
Authors: Precopio Melissa L. , Butterfield Tiffany R. , Casazza Joseph P. , Little Susan J. , Richman Douglas D. , Koup Richard A. , Roederer Mario
Published: September 2008

Mapping T‐cell epitopes for a pathogen or vaccine requires a complex method for screening hundreds to thousands of peptides with a limited amount of donor sample. We describe an optimized deconvolution process by which peptides are pooled in a matrix format to minimize the number of tests required to identify peptide epitopes. Four peptide pool matrices were constructed to deconvolute the HIV‐specific T‐cell response in three HIV‐infected individuals. ELISpot assays were used to map peptide antigens. Many HIV peptides were mapped in all three individuals. However, there were several challenges and limitations associated with the deconvolution process. Peptides that induced low‐frequency responses or were masked by peptide competition within a given pool were not identified, because they did not meet the threshold criteria for a positive response. Also, amino acid sequence variation limited the ability of this method to map autologous HIV peptides. Alternative analysis strategies and revisions to the original matrix optimizations are presented that address ways to increase peptide identification. This optimized deconvolution method allows for efficient mapping of T‐cell peptide epitopes. It is rapid, powerful, efficient, and unrestricted by HLA type. Published 2008 Wiley‐Liss, Inc.
Propagation of senescent mice using nuclear transfer embryonic stem cell lines
Authors: Mizutani Eiji , Ono Tetsuo , Li Chong , Maki‐Suetsugu Rinako , Wakayama Teruhiko
Published: September 2008

Senescent mice are often infertile, and the cloning success rate decreases with age, making it almost impossible to produce cloned progeny directly from such animals. In this study, we tried to produce offspring from such “unclonable” senescent mice using nuclear transfer techniques. Donor fibroblasts were obtained from the tail tips of mice aged up to 2 years and 9 months. Although most attempts failed to produce cloned mice by direct somatic cell nuclear transfer, we managed to establish nuclear transfer embryonic stem (ntES) cell lines from all aged mice with an establishment rate of 10–25%, irrespective of sex or strain. Finally, cloned mice were obtained from these ntES cells by a second round of nuclear transfer. In addition, healthy offspring was obtained from all aged donors via germline transmission of ntES cells in chimeric mice. This technique is thus applicable to the propagation of a variety of animals, irrespective of age or fertile potential. genesis 46:478‐483, 2008. © 2008 Wiley‐Liss, Inc.
Sall4 isoforms act during proximal–distal and anterior–posterior axis formation in the mouse embryo
Authors: Uez Nikolas , Lickert Heiko , Kohlhase Jürgen , de Angelis Martin Hrabe , Kühn Ralf , Wurst Wolfgang , Floss Thomas
Published: September 2008

Reciprocal signals from embryonic and extra‐embryonic tissues pattern the embryo in proximal–distal (PD) and anterior–posterior (AP) fashion. Here we have analyzed three gene trap mutations of Sall4, of which one (Sall4‐1a) led to a hypomorphic and recessive phenotype, demonstrating that Sall4‐1a has yet undescribed extra‐embryonic and embryonic functions in regulating PD and AP axis formation. In Sall4‐1a mutants the self‐maintaining autoregulatory interaction between Bmp4, Nodal and Wnt, which determines the PD axis was disrupted because of defects in the extra‐embryonic visceral endoderm. More severely, two distinct Sall4 gene‐trap mutants (Sall4‐1a,b), resembling null mutants, failed to initiate Bmp4 expression in the extra‐embryonic ectoderm and Nodal in the epiblast and were therefore unable to initiate PD axis formation. Tetraploid rescue underlined the extra‐embryonic nature of the Sall4‐1a phenotype and revealed a further embryonic function in Wnt/β‐catenin signaling to elongate the AP axis during gastrulation. This observation was supported through genetic interaction with β‐catenin mutants, since compound heterozygous mutants recapitulated the defects of Wnt3a mutants in posterior development. genesis 46:463–477, 2008. © 2008 Wiley‐Liss, Inc.
Serdin1/Lrrc10 is dispensable for mouse development
Authors: Manuylov Nikolay L. , Manuylova Ekaterina , Avdoshina Valeriya , Tevosian Sergei
Published: September 2008

We have previously identified Serdin1/Lrrc10 as a cardiac‐specific message that is expressed early in murine heart development and encodes a novel leucine‐rich protein. A high degree of evolutionary conservation with respect to protein sequence, cardiac‐specific expression, and cis‐regulatory elements suggested that LRRC10 has an important and conserved function in cardiac development. Recently, the zebrafish lrrc10 knockdown models were described with a dramatic early defect in heart looping which supported the notion that Serdin1/Lrrc10 is likely to be essential for heart development in all vertebrates. To determine Lrrc10 function in mammalian cardiac development, we have disrupted the Lrrc10 gene in mice. We report here that, in striking contrast to the zebrafish lrrc10 knockdown, Lrrc10‐null mice develop normally and exhibit no discernable phenotype. genesis 46:441‐446, 2008. © 2008 Wiley‐Liss, Inc.
Differentiation of the zebrafish enteric nervous system and intestinal smooth muscle
Authors: Olden Tasha , Akhtar Tanveer , Beckman Sarah A. , Wallace Kenneth N.
Published: September 2008

Development of the enteric nervous system is critical for normal functioning of the digestive system. In vertebrates, enteric precursors originate from the neural crest and migrate into the digestive system. Enteric neurons enable the digestive system to sense and respond to local conditions without the need for central nervous system input. Here we describe major steps in differentiation of the zebrafish enteric nervous system. During migration and neural differentiation of enteric precursors, we identify regions of the enteric nervous system in different phases of differentiation. Early in migration, a small group of anterior enteric neurons are first to form. This is followed by an anterior to posterior wave of enteric neural differentiation later in the migratory phase. Enteric precursors continue proliferating and differentiating into the third day of embryogenesis. nNOS neurons form early while serotonin neurons form late toward the end of enteric neural differentiation. Numbers of enteric neurons increase gradually except during periods of circular and longitudinal intestinal smooth muscle differentiation. genesis 46:484–498, 2008. © 2008 Wiley‐Liss, Inc.
The effects of causal beliefs and binge eating on the stigmatization of obesity
Authors: Bannon Katie L. , Hunter‐Reel Dorian , Wilson G. Terence , Karlin Robert A.
Published: September 2008

Objective:

Weight disorders and overeating are increasingly labeled as addictions. It is important to identify the consequences of this label on the stigmatization of obesity.

Method:

Participants (N = 374) were assigned randomly to one of six conditions, in which they read a scenario about an obese woman either with or without binge eating, followed by an account of the cause of her obesity as psychological, a biological addiction, or ambiguous. Participants then completed questionnaires designed to assess stigma and prognostic beliefs.

Results:

Participants in the obesity with binge eating condition rated obese persons more negatively and as having a worse prognosis. The causal manipulation check revealed no difference between groups and there were no significant effects of this condition.

Discussion:

Behavior (binge eating) has important implications for understanding the stigmatization of obesity. © 2008 by Wiley Periodicals, Inc. Int J Eat Disord 2009
Trans fatty acid content and positional distribution in refined and heated rice bran oil
Authors: Mezouari Samia , Eichner Karl
Published: September 2008

The objective of this study was to evaluate the impact of the refining process and of heating at frying temperature (180 °C, 8 h) on the content of trans fatty acids and their positional distribution in sn‐positions of triacylglycerols (TAG) of rice bran oil. Tr‐18:2 was an artifact specific to the deodorization step, which additionally changed its distribution at the 2‐MAG and 1,3‐DAG positions. No correlation between the formation of polymer TAG and trans fatty acids could be observed.
Zinc Homologation–Elimination Reaction of α‐Sulfinyl Carbanions as a New Route to Olefins
Authors: Abramovitch Adi , Marek Ilan
Published: September 2008

α‐Lithiosulfinyl carbanions react either intermolecularly, after transmetalation into an organocopper derivative in an SN2‐type process, with zinc carbenoids, or intramolecularly by higher‐order zincates through a tandem zinc homologation–β‐elimination reaction into the corresponding alkenes. α,α‐ and α,β‐Disubstituted alkenes can also be produced through these two methodologies.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis of Tertiary sec‐Alkylamines by the Addition of Grignard Reagents to N,N‐Dialkylformamides Mediated by Ti(OiPr)4 and Me3SiCl
Authors: Tomashenko Olesya , Sokolov Viktor , Tomashevskiy Alexander , Buchholz Herwig A. , Welz‐Biermann Urs , Chaplinski Vladimir , de Meijere Armin
Published: September 2008

A number of tertiary sec‐alkylamines (22 examples, 29–80 % yield) have been prepared according to a simple one‐pot procedure by the addition of Grignard reagents to N,N‐dialkylformamides in the presence of Ti(OiPr)4 and Me3SiCl. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Total Synthesis of L‐(+)‐Swainsonine and Other Indolizidine Azasugars from D‐Glucose
Authors: Alam Mohammad Abrar , Kumar Amit , Vankar Yashwant D.
Published: September 2008

A total synthesis of L‐(+)‐swainsonine, a potent and specific inhibitor of naringinase, along with the syntheses of six unnatural indolizidine azasugars are reported by starting from D‐glucose. L‐(+)‐Swainsonine was synthesized in 14 steps in 17 % overall yield. Further, two of the indolizidine analogues were found to be good glycosidase inhibitors at micromolar concentrations. In all of these syntheses, the key step was an intramolecular SN2 reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Experimental investigation of a maximum entropy assumption for acceleration terms within a poly‐disperse moment framework
Authors: Scott Stephen J. , Shrimpton John S.
Published: September 2008

Moment transport methods are being developed to model poly‐dispersed multiphase flows by transporting statistical moments of the particle size–velocity joint probability density function (JPDF). A common feature of these methods is the requirement to reproduce or approximate the form of the JPDF from the transported moments for calculation of body force terms and other source terms. This paper examines the application of a maximum entropy technique against phase Doppler anemometry data sets from an electrostatically charged kerosene spray and also an automotive pressure swirl atomizer. An assessment of which moments are required to reproduce the JPDFs using a maximum entropy assumption to a sufficient level of accuracy is made. It is found that it is possible to reproduce the JPDFs to a high level of accuracy using a large number of moments; however, this incurs large computational overheads. If the moments to be transported are chosen on the basis of physical reasoning (such as the relationship between size and velocity due to drag) it is possible to reduce the number of moments to those which would be conserved via balance equations. This permits an approximation to the JPDF commensurate with the closure level of the moment transport method and thus the closure model method is naturally scalable with the degree of information from available conservation equations. Copyright © 2008 John Wiley & Sons, Ltd.
A POD reduced‐order 4D‐Var adaptive mesh ocean modelling approach
Authors: Fang F. , Pain C. C. , Navon I. M. , Piggott M. D. , Gorman G. J. , Farrell P. E. , Allison P. A. , Goddard A. J. H.
Published: September 2008

A novel proper orthogonal decomposition (POD) inverse model, developed for an adaptive mesh ocean model (the Imperial College Ocean Model, ICOM), is presented here. The new POD model is validated using the Munk gyre flow test case, where it inverts for initial conditions. The optimized velocity fields exhibit overall good agreement with those generated by the full model. The correlation between the inverted and the true velocity is 80–98% over the majority of the domain. Error estimation was used to judge the quality of reduced‐order adaptive mesh models. The cost function is reduced by 20% of its original value, and further by 70% after the POD bases are updated.

In this study, the reduced adjoint model is derived directly from the discretized reduced forward model. The whole optimization procedure is undertaken completely in reduced space. The computational cost for the four‐dimensional variational (4D‐Var) data assimilation is significantly reduced (here a decrease of 70% in the test case) by decreasing the dimensional size of the control space, in both the forward and adjoint models. Computational efficiency is further enhanced since both the reduced forward and adjoint models are constructed by a series of time‐independent sub‐matrices. The reduced forward and adjoint models can be run repeatedly with negligible computational costs.

An adaptive POD 4D‐Var is employed to update the POD bases as minimization advances and loses control, thus adaptive updating of the POD bases is necessary. Previously developed numerical approaches Fang et al. (Int. J. Numer. Meth. Fluids 2008) are employed to accurately represent the geostrophic balance and improve the efficiency of the POD simulation. Copyright © 2008 John Wiley & Sons, Ltd.
The information content in implied idiosyncratic volatility and the cross‐section of stock returns: Evidence from the option markets
Authors: Diavatopoulos Dean , Doran James S. , Peterson David R.
Published: September 2008

Current literature is inconclusive as to whether idiosyncratic risk influences future stock returns and the direction of the impact. Earlier studies are based on historical realized volatility. Implied volatilities from option prices represent the market's assessment of future risk and are likely a superior measure to historical realized volatility. Implied idiosyncratic volatilities on firms with traded options are used to examine the relationship between idiosyncratic volatility and future returns. A strong positive link was found between implied idiosyncratic risk and future returns. After considering the impact of implied idiosyncratic volatility, historical realized idiosyncratic volatility is unimportant. This performance is strongly tied to small size and high book‐to‐market equity firms. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 28: 1013–1039, 2008
The economic value of volatility transmission between the stock and bond markets
Authors: Chuliá Helena , Torró Hipòlit
Published: September 2008

This study has two main objectives. Firstly, volatility transmission between stocks and bonds in European markets is studied using the two most important financial assets in these fields: the DJ Euro Stoxx 50 index futures contract and the Euro Bund futures contract. Secondly, a trading rule for the major European futures contracts is designed. This rule can be applied to different markets and assets to analyze the economic significance of volatility spillovers observed between them. The results indicate that volatility spillovers take place in both directions and that the stock‐bond trading rule offers very profitable returns after transaction costs. These results have important implications for portfolio management and asset allocation. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 28:1066–1094, 2008
Dynamic hedging with futures: A copula‐based GARCH model
Authors: Hsu Chih‐Chiang , Tseng Chih‐Ping , Wang Yaw‐Huei
Published: September 2008

In a number of earlier studies it has been demonstrated that the traditional regression‐based static approach is inappropriate for hedging with futures, with the result that a variety of alternative dynamic hedging strategies have emerged. In this study the authors propose a class of new copula‐based GARCH models for the estimation of the optimal hedge ratio and compare their effectiveness with that of other hedging models, including the conventional static, the constant conditional correlation (CCC) GARCH, and the dynamic conditional correlation (DCC) GARCH models. With regard to the reduction of variance in the returns of hedged portfolios, the empirical results show that in both the in‐sample and out‐of‐sample tests, with full flexibility in the distribution specifications, the copula‐based GARCH models perform more effectively than other dynamic hedging models. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 28:1095–1116, 2008