bluuebunny/crossref_metadata_2025 huggingface dataset:
Stereoselective Intramolecular Oxazine Formation by a π‐Allylpalladium Complex Catalyzed by Pd0
Authors: Joo Jae‐Eun , Lee Kee‐Young , Pham Van‐Thoai , Ham Won‐Hun
Published: February 2007

An efficient procedure for synthesizing oxazines was developed by the palladium(0)‐catalyzed intramolecular cyclization of a benzamide through a π‐allylpalladium(II) complex. Unlike other palladium‐catalyzed reactions, the temperature was found to be a key factor in determining the stereochemistry of the oxazine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A Pronounced Anionic Effect in the Pd‐Catalyzed Buchwald–Hartwig Amination Reaction Revealed in Phosphonium Salt Ionic Liquids
Authors: McNulty James , Cheekoori Sreedhar , Bender Timothy P. , Coggan Jennifer A.
Published: February 2007

The Pd‐mediated Buchwald–Hartwig amination reaction of aryl halides in a phosphonium salt ionic liquid consisting of a trihexyl(tetradecyl)phosphonium cation with a range of anions has been investigated. A pronounced anionic effect was uncovered with the reaction proceeding readily with weakly nucleophilic diarylamines only in the presence of noncoordinating anions. A mechanism is postulated to explain these results and it involves a rate‐limiting ligand exchange step that proceeds through a dissociative pathway.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Low Potential Detection of NADH at Titanium‐Containing MCM‐41 Modified Glassy Carbon Electrode
Authors: Dai Zhihui , Lu Guofei , Bao Jianchun , Huang Xiaohua , Ju Huangxian
Published: February 2007

Titanium‐containing MCM‐41 (Ti‐MCM‐41) modified glassy carbon electrode (GCE) can exhibit an excellent electrocatalytic activity towards the oxidation of β‐Nicotinamide adenine dinucleotide (NADH). A dramatic decrease in the over‐voltage of NADH oxidation reaction is observed at 0.28 V (vs. SCE). The modified electrode is found to be stable and reproducible. The electrode shows a linear response for a wide range of 10–1200 μM NADH and the detection limit is 8.0 μM. Ti‐MCM‐41 mesoporous molecular sieves provide an efficient matrix for development of NADH biosensors and the prepared electrode not only can be used to detect the concentration of NADH in biochemical reaction, but also as the potential matrix of the construction of dehydrogenases biosensor.
Development of Streptavidin Carrying Magnetic Nanoparticles and Their Applications in Electrochemical Nucleic Acid Sensor Systems
Authors: Erdem Arzum , Sayar Filiz , Karadeniz Hakan , Guven Guldem , Ozsoz Mehmet , Piskin Erhan
Published: February 2007

The aim of this study is to investigate the applicability of streptavidin carrying magnetic nanoparticles in electrochemical nucleic acid sensor systems. The magnetite (Fe3O4) nanoparticles were prepared by co‐precipitation technique, and then they were coated with a carboxylic acid containing polymer layer. Streptavidin molecules were immobilized onto the surfaces of these magnetic nanoparticles (with two different average diameter of 125 and 225 nm) via these functional groups. An electrochemical nucleic acid sensor system composed of a disposable graphite sensor, pencil graphite electrode (PGE) and differential pulse voltammetry (DPV) was used for measurement of guanine oxidation signal observed at +1.0 V. In the hybridization tests biotinylated inosine substituted probe was immobilized onto the magnetic nanoparticles and hybridization with its complementary target at the surface of particles within the medium was exhibited successfully by using this electrochemical sensor system. For electrochemical detection of sequence specific DNA hybridization and its selectivity studies, the biotinylated hepatitis B Virus (HBV) wild type probe was immobilized onto the nanoparticles. The guanine oxidation signals were measured in the solutions containing no target, the complementary target, a single‐base mismatch target, and noncomplementary target oligonucleotides. A significant guanine oxidation signal (71 nA) was observed with the complementary target due to complete hybridization, while with single‐base mismatch target, the signal at the same conditions was quite low about 14 nA. However, in the case of the noncomplementary target, there was a low but observable mean signal about 9 nA (showing the nonspecific interaction). The detection limit (S/N=3) was found as 43.11 pmol/mL target concentration obtained in 20 min hybridization time.
GABAB receptor blockade enhances theta and gamma rhythms in the hippocampus of behaving rats
Authors: Leung L. Stan , Shen Bixia
Published: February 2007

The participation of GABAB receptors in hippocampal EEG generation was studied by intracerebroventricular (icv) and intracerebral infusions of GABAB receptor antagonist p‐(3‐aminopropyl)‐p‐diethoxymethyl‐phosphinic acid (CGP35348) in freely behaving rats. During awake‐immobility, icv CGP35348 induced a theta rhythm and increased gamma waves (30–100 Hz) in the hippocampus. The immobility theta peaked at 6–7 Hz and had a theta phase in CA1 stratum radiatum of ∼160° with reference to the theta at the alveus, when compared with ∼130° during walking. Immobility theta power peaks at 6–7 Hz was also found in normal rats, and it was detected in 27% of the EEG segments during immobility. Incidence of immobility theta increased to 87.5% after 480 nmol of CGP35348 icv. Muscarinic antagonist scopolamine (5 mg/kg, ip) suppressed the induction of immobility theta and the gamma power increase after icv CGP35348. CGP35348 icv did not significantly change the hippocampal theta power at 7–8 Hz during walking (theta fundamental), but it increased power at 12–15 Hz, at the second harmonic of theta. CGP35348 icv also increased 30–50 Hz gamma power during walking. Medial septal infusion of CGP35348 (12 nmol in 0.4 μl) increased the power and the frequency of the hippocampal theta second harmonic during walking, but did not increase gamma activity. Infusion of CGP35348 (8 nmol in 0.4 μl) in the hippocampus increased the local gamma activity at 30–100 Hz, but did not induce immobility theta or affect the walking theta rhythm. In conclusion, icv GABAB receptor blockade increased an atropine‐sensitive input that generated an immobility theta rhythm, while GABAB receptor blockade of the medial septum increased atropine‐resistant theta harmonics possibly generated by apical dendritic spikes. GABAB receptor blockade may enhance cognitive task performance by activating hippocampal theta and gamma rhythms in behaving rats. © 2007 Wiley‐Liss, Inc.
Neutrophil gelatinase‐associated lipocalin (NGAL) an early‐screening biomarker for ovarian cancer: NGAL is associated with epidermal growth factor‐induced epithelio‐mesenchymal transition
Authors: Lim Ratana , Ahmed Nuzhat , Borregaard Niels , Riley Clyde , Wafai Razan , Thompson Erik W. , Quinn Michael A. , Rice Gregory E.
Published: February 2007

The expression of neutrophil gelatinase‐associated lipocalin (NGAL) has been shown to be upregulated in ovarian cancer cells. In this study, we report that the expression of immunoreactive NGAL (irNGAL) in ovarian tumors changes with disease grade and that this change is reflected in the concentration of NGAL in peripheral blood. A total of 59 ovarian tissues including normal, benign, borderline malignant and grades 1, 2 and 3 malignant were analyzed using immunohistochemistry. irNGAL was not present in normal ovaries and the NGAL expression was weak to moderate in benign tissues. Both borderline and grade 1 tumors displayed the highest amount of NGAL expression with moderate to strong staining, whereas in grade 2 and 3 tumors, the extent of staining was significantly less (p < 0.01) and staining intensity was weak to moderate. Staining in all cases was confined to the epithelium. NGAL expression was analyzed by ELISA in 62 serum specimens from normal and different grades of cancer patients. Compared to control samples, the NGAL concentration was 2 and 2.6‐fold higher in the serum of patients with benign tumors and cancer patients with grade 1 tumors (p < 0.05) and that result was consistent with the expression of NGAL performed by Western blot. NGAL expression was evaluated by Western blot in an immortalized normal ovarian cell line (IOSE29) as well as ovarian cancer cell lines. Moderate to strong expression of NGAL was observed in epithelial ovarian cancer cell lines SKOV3 and OVCA433 while no expression of NGAL was evident in normal IOSE29 and mesenchyme‐like OVHS1, PEO.36 and HEY cell lines. NGAL expression was downregulated in ovarian cancer cell lines undergoing epithelio‐mesenchymal transition (EMT) induced by epidermal growth factor (EGF). Downregulation of NGAL expression correlated with the upregulation of vimentin expression, enhanced cell dispersion and downregulation of E‐cadherin expression, some of the hallmarks of EMT. EGF‐induced EMT phenotypes were inhibited in the presence of AG1478, an inhibitor of EGF receptor tyrosine kinase activity. These data indicate that NGAL may be a good marker to monitor changes of benign to premalignant and malignant ovarian tumors and that the molecule may be involved in the progression of epithelial ovarian malignancies. © 2007 Wiley‐Liss, Inc.
Circulating KL‐6/MUC1 mucin carrying sialyl Lewisa oligosaccharide is an independent prognostic factor in patients with lung adenocarcinoma
Authors: Inata Junya , Hattori Noboru , Yokoyama Akihito , Ohshimo Shinichiro , Doi Mihoko , Ishikawa Nobuhisa , Hamada Hironobu , Kohno Nobuoki
Published: February 2007

MUC1 mucin is frequently observed in adenocarcinomas, and its association with metastasis has been postulated through the interaction between sialyl Lewis oligosaccharides present on this glycoprotein and selectins. Levels of soluble MUC1 recognized by anti‐KL‐6 monoclonal antibody were also frequently elevated in the sera of lung adenocarcinoma patients. The aim of this study was to demonstrate the presence of KL‐6/MUC1 carrying sialyl Lewisa oligosaccharide, designated as SLAK, and subsequently evaluate the clinical significance of circulating SLAK in patients with lung adenocarcinoma. We developed a sandwich ELISA system using anti‐sialyl Lewisa and anti‐KL‐6 antibodies to detect SLAK, and also measured circulating SLAK levels in 97 healthy controls and 103 patients with lung adenocarcinoma. Circulating SLAK levels were measured in the sera taken before treatment and then were evaluated to clarify whether such levels were related to the clinical outcomes. Levels of circulating SLAK were significantly higher in lung adenocarcinoma patients than in healthy subjects, and a higher serum SLAK level was correlated with the presence of distant metastasis. The overall survival rate for patients with high serum SLAK levels was significantly poorer than that of patients with low serum SLAK levels. The survival analysis restricted to the patients with distant metastasis also showed the same trend. In a multivariate survival analysis in lung adenocarcinoma patients, a high serum SLAK level was indicated as an independent prognostic factor. In conclusion, the circulating SLAK level at diagnosis is useful for predicting a poor prognosis in patients with lung adenocarcinoma. © 2007 Wiley‐Liss, Inc.
Neurotoxic activity of Gln49 phospholipase A2 from Gloydius ussuriensis snake venom
Authors: Chang Yan , Li Yingxue , Bao Yongming , An Lijia
Published: February 2007

A novel neurotoxic protein phospholipase A2 (PLA2), molecular weight 13 881.83 Da, has been isolated from snake venom of Gloydius ussuriensis, named as Gln49‐PLA2, which shows weak lethal toxic, myotoxic and apparent anticoagulant activity, but lacks phospholipase activity. The Gln49‐PLA2 obviously induced an increase of the pain threshold in intoxicated 615 mice compared with the control group, suggesting it is a neurotoxin. Hot‐plate tests also showed that its analgesic activity was dose‐dependent, and naloxone antagonized the analgesic effect, implying the mechanism of action of Gln49‐sPLA2 is correlated with opioid receptors. Electrophysiology studies revealed decreases in the action potential and the nerve conduction velocity in isolated hoptoad (Bufo bufo gargarizans Cantor) sciatic nerve, indicating Gln49‐PLA2 most probably had effects on ion channels. Copyright © 2007 John Wiley & Sons, Ltd.
Micro processing with laser radiation – Trends and perspectives
Authors: Gillner Arnold
Published: February 2007

Miniaturization and highly integrated functionalization are the driving factors in the production of innovative products in almost every industrial area today: Electronic components require conducting traces smaller than 100 μm und 3‐dimensional interconnections, highly fuel efficient cars are only possible by micro structured functional surfaces and injection nozzles with geometries <100 μm, medical products require selective functionalization for improved fluid control and micro optical components increase the functionality in a large variety of consumer products like mobile phones and miniaturized cameras.
Creating distinct value – How Coherent pursues further growth in laser markets
Authors: Meissner Paul
Published: February 2007

In the last decades, the laser business has seen tremendous progress but also the trouble of the telecom crisis. Today the business is steadily growing. This process is connected not only with expanding markets, but also with a rapid innovation cycle. LTJ spoke with Paul Meissner, Executive Vice President of Global Business Operations at Coherent Inc. about the strategy Coherent Inc. is pursuing in the competition for new markets and new ideas.
Characteristics of apathy in Parkinson's disease
Authors: Dujardin Kathy , Sockeel Pascal , Devos David , Delliaux Marie , Krystkowiak Pierre , Destée Alain , Defebvre Luc
Published: February 2007

The objective of this study was to use the Lille Apathy Rating Scale to assess apathy in a large population of Parkinson's disease (PD) patients and identify several different apathy profiles. One hundred fifty‐nine patients with probable PD and 58 healthy controls participated in the study. Apathy was assessed using the Lille Apathy Rating Scale. Motor, cognitive, and depressive symptoms were rated on standardized scales. Data were analyzed using linear regression and multivariate analyses of variance. Thirty‐two percent of the PD patients were classified as apathetic. Apathy was more frequent in patients with dementia. The four apathy dimensions contributed differently to the overall severity of the apathetic condition. Action initiation and intellectual curiosity had a marked influence. Linear regression analysis revealed that the apathy level was mainly determined by cognitive impairment, not associated with the severity of motor symptoms, and only associated with the apathy subcomponent of the Montgomery and Asberg Depression Rating Scale. Apathy is highly prevalent in PD patients. Apathy profiles vary according to the clinical presentation of PD. The high prevalence of apathy in PD suggests the involvement of frontal–subcortical circuits. Although the neurochemical substrate of apathy remains poorly characterized, the strong link between apathy and cognitive impairment observed in several studies suggests the participation of nondopaminergic circuits. © 2007 Movement Disorder Society
Synthesis, Morphology and Rheological Behavior of Fluoropolymer‐Polyacrylate Nanocomposites
Authors: Suresh Kattimuttathu I. , Pakula Tadeusz , Bartsch Eckhard
Published: February 2007

Nanocomposite materials composed of a PTFE copolymer core and an acrylic copolymer shell have been prepared by seeded emulsion polymerization. The effect of seed particle number and shell polymer composition on secondary particle nucleation and film formation ability of the dispersions has been studied. While TEM reveals a core‐shell structure present in the particles, AFM investigation of the film shows a nearly uniform dispersion of the fluorinated seed particles in a matrix formed by the shell polymer. Rheological measurements show composite behavior of the core‐shell latex films, especially at elevated temperatures, and an increase in viscosity and storage modulus when compared with the properties of the pure acrylic component. These composites exhibit a solid‐like behavior at lower frequencies (in the rubbery zone) indicating the formation of a network‐like structure which acts as a reinforcement for the acrylic matrix. The process takes place faster at higher temperatures, probably due to the increased mobility of the cores and a corresponding improvement of the mechanical properties is observed. The fluoropolymer‐PBMA nanocomposite films also show opalescent crystal like behavior due to the existence of a refractive index gradient.

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Synthesis and Properties of a Superabsorbent Polymer Prepared by Copolymerization of Sodium Acrylate with Sodium 1‐(Acryloyloxy)propan‐2‐yl Phosphate
Authors: Chen Zhenbin , Liu Mingzhu , Qi Xiaohua
Published: February 2007

A novel monomer, 1‐(acryloyloxy)propan‐2‐yl phosphoryl dichloride, was synthesized and characterized in this work. Thereafter, the monomer was neutralized with sodium hydroxide and copolymerized with sodium acrylate to obtain a superabsorbent polymer. The superabsorbent polymer was then modified to improve its swelling properties (i.e., the water absorbency under load, the hydrogel strength, the resilience and the dispersion). Both single factor and orthogonal design experiments were adopted to obtain optimal conditions. The superabsorbent polymer prepared under the optimal conditions showed improved water absorbency in physiological saline [17 g · g−1 under load (P = 2 × 103 Pa) and 65 g · g−1 at atmospheric pressure] and other swelling properties, such as hydrogel strength, resilience and dispersion, also improved.

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Direction sensitive sensor probe for the evaluation of voluntary and reflex pelvic floor contractions
Authors: Constantinou Christos E. , Omata Sadao
Published: February 2007

Aims

The development of a vaginal probe for the evaluation of the dynamics of pelvic floor function is described. Fundamental criteria in the design of this probe involves the incorporation of a means of assessing whether the isotonic forces closing the vagina are equally distributed or whether they are greater in some directions than others. The aim of this study is to present the design of directionally sensitive multi‐sensor probe, having circumferential spatial resolution, constructed to identify the distribution of anisotropic forces acting on the vagina following voluntary and reflex pelvic floor contractions.

Materials and Methods

Probe system consists of four pairs of force/displacement sensors mounted on leaf springs enabling isotonic measurements of voluntary and reflex contractions. Assembly is retractable to 23 mm for insertion, and expandable to 60 mm for measurement. Simultaneous measurements were made of force and displacement with the sensors oriented in the anterior/posterior and left/right orientation of the vagina. Using this probe, measurements were carried out to identify the temporal and spatial characteristic response of the vaginal wall. Data were analyzed with respect to voluntary pelvic floor and cough‐induced contractions of nine subjects having a mean age of 64 years.

Results

A robust probe system was developed and measurements were successfully made. Initial results show that the maximum force and displacement occurs during reflex contractions in the anterior aspect of the vagina validating the anisotropic nature of the forces acting on the vaginal wall. The data also show that both the force and displacement produced by the cough‐induced has a higher magnitude than voluntary pelvic floor contraction.

Conclusions

A directional multi‐sensor vaginal probe has been developed to evaluate the force and displacement produced during isotonic pelvic floor contractions. Analysis of the results provided new biomechanical data demonstrating the anisotropic nature of vaginal closure as a consequence of pelvic floor contractions. Neurourol. Urodynam. 26:386–391, 2007. © 2007 Wiley‐Liss, Inc.
Preparation and characterization of polyether‐block‐amide copolymer/clay nanocomposites
Authors: Yang I‐Kuan , Tsai Ping‐Hung
Published: February 2007

A polyether‐block‐amide copolymer was successfully blended with eight organoclays and one sodium montmorillonite by melt processing technique to form nanocomposites. X‐ray diffraction, thermogravimetry, differential scanning calorimeter analysis, dynamic mechanical analysis, tensile test, and linear viscoelastic analysis were used to characterize the hybrids. The molecular structure of the surfactants in the organoclays was found having a significant impact on the viscoelasticity and the d‐spacing gain of the clays. Hybrids from organoclays using surfactants with a single long alkyl tail had a higher d‐spacing gain than those from organoclays using surfactants with two long alkyl tails. The melt viscoelasticity was found excellently correlated to the d‐spacing gain and hence the linear viscoelasticity could be an excellent indicator for platelet organization in the composites. The melt viscoelasticity is fairly correlated to the tensile modulus and glass transition temperature of the soft and hard segment, implying that the platelet organization plays a role in these properties. Properties such as melting point, thermal degradation temperature, elongation at break, and tensile strength are not correlated to the viscoelasticity. The failure indicates that these properties are irrelevant to or less influenced by the platelet organization. POLYM. ENG. SCI., 47:235–243, 2007. © 2007 Society of Plastics Engineers.
Supramolecular design in biopolymers and biomimetic polymers for advanced mechanical properties
Authors: Guan Zhibin
Published: February 2007

This mini review uses two examples to illustrate the importance of supramolecular chemistry in natural and biomimetic polymers for advanced mechanical properties. In the first example, dragline silk, one of the strongest and toughest natural fibers, uses intermolecular weak forces to self‐assemble into nanocomposites composed of β‐sheet nanocrystals imbedded in an amorphous matrix. In the second example, a load‐bearing protein, the sarcomere muscle protein titin, uses intramolecular weak forces to fold into repetitive modules for combined strength, toughness, and elasticity. Both examples show vividly that many natural polymers can combine important mechanical properties through programming supramolecular weak interactions into covalently formed biopolymers. This mini review attempts to summarize the current understanding of the molecular mechanisms that contribute to the exceptional mechanical properties for each natural polymer. Following that, the efforts from others and the author's own laboratory on developing synthetic polymers to mimic these natural counterparts are discussed. Copyright © 2007 Society of Chemical Industry
Host–guest complexes of phenol derivatives with β‐cyclodextrin: an experimental and theoretical investigation
Authors: Chelli Saloua , Majdoub Mustapha , Jouini Mohamed , Aeiyach Salah , Maurel François , Chane‐Ching Kathleen I. , Lacaze Pierre‐Camille
Published: February 2007

β‐Cyclodextrin (β‐CD) is used as the host molecule to study the inclusion of a series of bent [bisphenol A (BPA) and fluorinated bisphenol A (FBPA)] or linear [biphenol (BIP) and isopropylphenol (IPP)] phenol derivatives. Experimental and theoretical investigations reveal that the complexes with the bent BPA and FBPA molecules are more stable than those with the linear IPP and BIP molecules. This stability difference is attributed to differences in the geometries which, in the case of bent molecules, seems to prevent the unthreading of the guest. The optimized geometry of the BIP/β‐CD complex shows a particularly strong deviation of the principal axis of BIP from the vertical symmetry axis (C7) of β‐CD. For bent molecules, the same sort of deviation is due to the second aromatic residue, which is outside the cavity, approaching the wider rim of the β‐CD, probably because of van der Waals interactions. In the FBPA/β‐CD system, experimental results (19F NMR) and DFT (MPWB1K//AM1) calculations demonstrate a different complexation mode from that of the three other systems, with high interaction energy, the phenol residues are located outside the β‐CD cavity but fluorinated alkyls are inside. This agreement indicates that MPWB1K/6‐31G(d) single point calculation based on AM1 geometries is a useful predictive tool for such series, even for systems as large as ours. Copyright © 2007 John Wiley & Sons, Ltd.
Kinetic study of electrochemically induced Michael reactions of o‐benzoquinones with 2‐acetylcyclohexanone and 2‐acetylcyclopentanone
Authors: Nematollahi Davood , Alimoradi Mohammad , Rafiee Mohammad
Published: February 2007

The reaction of electrochemically generated o‐benzoquinones (2a‐f) as Michael acceptors with 2‐acetylcyclohexanone (ACH) and 2‐acetylcyclopentanone (ACP), as nucleophiles has been studied in various pHs using cyclic voltammetry. The results indicate that the participation of o‐benzoquinones (2a‐f) in the Michael reaction with acetylcyclohexanone (ACH) to form the corresponding catechol derivatives (4a‐f). Based on an EC mechanism, the homogeneous rate constants were estimated by comparing the experimental cyclic voltammetric responses with the digital simulated results. Copyright © 2007 John Wiley & Sons, Ltd.
Kinetics and mechanism of uncatalysed and ruthenium(III) catalysed oxidation of allyl alcohol by diperiodatoargentate(III) in aqueous alkaline medium
Authors: Tegginamath Veeresh , Hiremath Chanabasayya V. , Nandibewoor Sharanappa T.
Published: February 2007

The oxidation of allyl alcohol by diperiodatoargentate(III) (DPA) is carried out both in the absence and presence of ruthenium(III) catalyst in alkaline medium at 298 K and a constant ionic strength of 1.1 mol dm−3 was studied spectrophotometrically. The oxidation products in both the cases were acrolein and Ag(I), identified by spectral studies. The stoichiometry is same in both the cases, that is, [AA]/[DPA] = 1:1. The reaction shows first order in [DPA] and has less than unit order dependence each in both [AA] and [Alkali] and retarding effect of [IO] in both the catalysed and uncatalysed cases. The order in [Ru(III)] is unity. The active species of DPA is understood to be as monoperiodatoargentate(III) (MPA) in both the cases. The uncatalysed reaction in alkaline medium has been shown to proceed via a MPA–allyl alcohol complex, which decomposes in a rate determining step to give the products. In catalysed reaction, it has been shown to proceed via a Ru(III)‐allyl alcohol complex, which further reacts with one molecule of MPA in a rate determining step to give the products. The reaction constants involved in the different steps of the mechanisms were calculated for both reactions. The catalytic constant (Kc) was also calculated for catalysed reaction at different temperatures. The activation parameters with respect to slow step of the mechanisms were computed and discussed for both the cases. The thermodynamic quantities were also determined for both reactions. Copyright © 2007 John Wiley & Sons, Ltd.
New results in robust actuator fault reconstruction for linear uncertain systems using sliding mode observers
Authors: Ng Kok Yew , Tan Chee Pin , Edwards Christopher , Kuang Ye Chow
Published: February 2007

This paper presents a robust actuator fault reconstruction scheme for linear uncertain systems using sliding mode observers. In existing work, fault reconstruction via sliding mode observers is limited to either linear certain systems subject to unknown inputs, relative degree one systems or a specific class of relative degree two systems. This paper presents a new method that is applicable to a wider class of systems with relative degree higher than one, and can also be used for systems with more unknown inputs than outputs. The method uses two sliding mode observers in cascade. Signals from the first observer are processed and used to drive the second observer. Overall, this results in actuator fault reconstruction being feasible for a wider class of systems than using existing methods. A simulation example verifies the claims made in this paper. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis, design, and performance limitations of H∞ optimal filtering in the presence of an additional input with known frequency
Authors: Saberi Ali , Stoorvogel Anton A. , Sannuti Peddapullaiah
Published: February 2007

A generalized γ‐level H∞ sub‐optimal input decoupling (SOID) filtering problem is formulated. It is a generalization of γ‐level H∞ SOID filtering problem when, besides an input with unknown statistical properties but with a finite RMS norm, there exists an additional input to the given plant or system. The additional input is a linear combination of sinusoidal signals each of which has an unknown amplitude and phase but known frequency. The analysis, design, and performance limitations of generalized H∞ optimal filters are presented. Copyright © 2007 John Wiley & Sons, Ltd.
Assembly of Metal Nanoparticles into Nanogaps
Authors: Barsotti Robert J. , Vahey Michael D. , Wartena Ryan , Chiang Yet‐Ming , Voldman Joel , Stellacci Francesco
Published: February 2007

The directed assembly of nanoparticles and nanoscale materials onto specific locations of a surface is one of the major challenges in nanotechnology. Here we present a simple and scalable method and model for the assembly of nanoparticles in between electrical leads. Gold nanoparticles, 20 nm in diameter, were assembled inside electrical gaps ranging from 15 to 150 nm with the use of positive ac dielectrophoresis. In this method, an alternating current is used to create a gradient of electrical field that attracts particles in between the two leads used to create the potential. Assembly is achieved when dielectrophoretic forces exceed thermal and electrostatic forces; the use of anchoring molecules, present in the gap, improves the final assembly stability. We demonstrate with both experiment and theory that nanoparticle assembly inside the gap is controlled by the applied voltage and the gap size. Experimental evidence and modeling suggest that a gap‐size‐dependent threshold voltage must be overcome before particle assembly is realized. Assembly results as a function of frequency and time are also presented. Assembly of fewer than 10 isolated particles in a gap is demonstrated. Preliminary electrical characterization reveals that stable conductance of the assembled particles can be achieved.
The hijab and systemic governance: transnational policy making and human rights
Authors: McIntyre Janet J.
Published: February 2007

The banning of the hijab along with other religious symbols in French public schools from 1st September 2004 can be cited as an example of a complex issue. It is also an example of policy making, that treats the wearing of the hijab (and other religious symbols) as representative of an essentialist religious category that is symbolic of both identity and worldview. All religious symbols in public schools are banned, but the discretion is with local schools as to how the law will be managed through discussion with the student. This article addresses the policy by ‘unfolding’ the values of the different stakeholders and ‘sweeping in’ the social, cultural, political, economic and environmental factors (adapted from Churchman, 1979a, b, 1984, who cites Edgar Singer). Both cultures Christian and Muslim need to consider the merits of using the least powerful as a site for the struggle over identity politics, shorthand for the systemic fall out post 9/11. Copyright © 2007 John Wiley & Sons, Ltd.
Biomarker validation of a long‐chain omega‐3 polyunsaturated fatty acid food frequency questionnaire
Authors: Sullivan Bethany L. , Williams Peter G. , Meyer Barbara J.
Published: February 2007

Long‐chain omega‐3 PUFA (LC n−3 PUFA) are beneficial for health. To date there is no specific food frequency questionnaire (FFQ) to assess LC n−3 PUFA intakes. The objective of this study is to validate our newly developed FFQ by comparison with LC n−3 PUFA content of both red blood cells (RBC) and plasma, expressed as a percentage of total FA. Fifty‐three healthy male and female subjects were recruited from Wollongong, Australia. Average LC n−3 PUFA intakes (mg/d) were estimated using the new FFQ. RBC and plasma FA were assessed using GC. Spearman correlation coefficients were used to assess the linear relationship between FFQ intakes and both RBC and plasma FA. The results show that there were significant Spearman's correlation coefficients between the FFQ intakes and RBC (and plasma) FA for total LC n−3 PUFA, EPA, and DHA (0.50 (0.54), 0.39 (0.54) and 0.40 (0.48), respectively) but not for docosapentaenoic acid. The FFQ was also an effective ranking tool. The FFQ is a valid method based on erythrocyte and plasma FA as biochemical markers. In conclusion, the new FFQ is a valid method that can be used to estimate the LC n−3 PUFA intake of adults.
Bovine muscle n−3 fatty acid content is increased with flaxseed feeding
Authors: Kronberg S. L. , Barceló‐Coblijn G. , Shin J. , Lee K. , Murphy E. J.
Published: February 2007

We examined the ability of n−3 FA in flaxseed‐supplemented rations to increase the n−3 FA content of bovine muscle. Two groups of animals were used in each of two separate trials: (i) Hereford steers supplemented (or not) with ground flaxseed (907 g/d) for 71 d, and (ii) Angus steers supplemented (or not) with ground flaxseed (454 g/d for 3 d followed by 907 g/d for 110 d). For the Hereford group, flaxseed‐supplemented rations increased 18∶3n−3 (4.0‐fold), 20∶5n−3 (1.4‐fold), and 22∶5n−3 (1.3‐fold) mass as compared with the control, and increased total n−3 mass about 1.7‐fold. When these data were expressed as mol%, the increase in 18∶3n−3 was 3.3‐fold and in 20∶5n−3 was 1.3‐fold in the phospholipid fraction, and 18∶3n−3 was increased 4‐fold in the neutral lipid fraction. For the Angus group, flaxseed ingestion increased masses and composition of n−3 FA similarly to that for the Herefords and doubled the total n−3 FA mass. The effect of cooking to a common degree of doneness on FA composition was determined using steaks from a third group of cattle, which were Angus steers. We demonstrated no adverse effects on FA composition by grilling steaks to an internal temperature of 64°C. Because n−3 FA may affect gene expression, we used quantitative real‐time reverse transcriptase‐polymerase chain reaction to quantify the effect of feeding flaxseed on heart‐FA binding protein, peroxisome proliferator activated receptor γ (PPARγ) and α (PPARα) gene expression in the muscle tissue. PPARγ mRNA level was increased 2.7‐fold in the flaxseed‐fed Angus steers compared with the control. Thus, we demonstrate a significant increase in n−3 FA levels in bovine muscle from cattle fed rations supplemented with flaxseed and increased expression of genes that regulate lipid metabolism.
Cyclic fluctuations of 3‐hydroxy‐3‐methylglutaryl‐CoA reductase in aortic smooth muscle cell cultures
Authors: Alejandre Ma José , Perales Sonia , Carazo Ángel , Palomino‐Morales Rogelio , Linares Ana
Published: February 2007

The cyclic fluctuations of HMG‐CoA reductase activity and mRNA are reportedly related to feeding the cells in culture or to variations in food consumption by the animals over a 24‐h cycle. In this work, we demonstrate cyclic increments in HMG‐CoA reductase activity in smooth muscle cells (SMC) not associated with the culture feeding. Since reductase activity also shows a marked rise preceding the S phase, one of the major goals of the present work was to evaluate this dual role of reductase activity and mRNA fluctuations related to the cell cycle and to food intake in the SMC‐C/SMC‐Ch cultures derived from control‐fed (SMC‐C) and cholesterol‐fed (SMC‐Ch) chicks. The period and amplitude oscillations in HMG‐CoA reductase activity varied depending on culture conditions: lipoprotein‐deficient serum vs. FBS, young vs. senescent cells, or confluent vs. nonconfluent cultures. The HMG‐CoA reductase mRNA concentration showed a marked rise after feeding not correlated to the fluctuation activity, suggesting posttranscriptional modulation. Reductase activity and mRNA were down‐regulated in SMC‐Ch. Since the nutritional culture conditions were the same in both cell lines, these findings indicate that consumption of a high‐cholesterol diet by the animals prior to the establishment of the SMC cultures induced changes in the HMG‐CoA reductase gene expression in aortic SMC.
Varietal and crop year effects on lipid composition of walnut (Juglans regia) genotypes
Authors: Martínez Marcela L. , Mattea Miguel A. , Maestri Damián M.
Published: February 2007

The FA, unsaponifiable, and volatile constituents of oil from three walnut varieties from two consecutive crop years were studied. The walnut oils (WO) were rich in PUFA and low in saturated FA. The tocopherol fraction consisted mainly of γ‐tocopherol. High contents of β‐sitosterol were found, together with campesterol and Δ5‐avenasterol in similar amounts. Methylsterols present in WO were identified as cycloartenol, cyclolaudenol, cycloeucalenol, and 24‐methylenecycloartanol. The hydrocarbon fraction was characterized by the predominance of C14–C20n‐alkanes. The major volatiles were aldehydes produced through the linoleic acid oxidative pathway. FA, methylsterols, and some hydrocarbons presented statistically significant differences among varieties. Most of this variation was due to the genotype. The Franquette variety was noteworthy by its higher oil and oleic acid contents. In contrast, tocopherols and volatile compounds showed minor differences among varieties; they were strongly influenced by the crop year. Chemical data were subjected to principal component analysis. The parameters that gave the greatest discrimination between the walnut varieties were oleic and linolenic acids, tetradecane, eicosane, tetracosane, cycloartenol, and 24‐methylenecycloartanol. These components presented the major varietal influences and could be useful to determine the identity of walnut genotypes.
Influence of seasonal conditions on the composition and quality parameters of monovarietal virgin olive oils
Authors: Morelló José Ramón , Romero Maria Paz , Motilva Maria José
Published: February 2007

The aim of this work was to determine the effect of the climatological conditions of the olive crop season on the composition of monovarietal virgin olive oils obtained from the Arbequina cultivar with special emphasis on the phenolic fraction, its percent distribution, and related oil quality parameters such as oxidative stability and bitter index. The main differences were due to freeze injuries caused by low temperatures in December 2001. The levels of chlorophylls and carotenoids in olive oil or pulp from frost‐damaged olive trees were lower as a consequence of faster ripening. The olive oil extracted from frost‐damaged olive pulp had lower contents of secoiridoid and especially lower levels of 3,4‐DHPEA‐EDA (the dialdehydic form of elenolic acid linked to hydroxytyrosol). In the following crop seasons, a significant increase in phenolic compounds, especially in secoiridoid derivatives such as 3,4‐DHPEA‐EDA, was observed. This increase may be due to the fact that olive trees that suffered frost damage in December 2001 were more sensitive to stress caused by the water deficit during summer in the subsequent crop seasons, which is usual in this olive‐growing region. Moreover, important correlation coefficients were observed between the main secoiridoid derivative compound (3,4‐DHPEA‐EDA) and oxidative stability and the bitter index.
Enzymatic hydrolysis of extruded‐expelled soy flour and resulting functional properties
Authors: Lamsal B. P. , Reitmeier C. , Murphy P. A. , Johnson L. A.
Published: February 2007

Limited hydrolysis (4% degree of hydrolysis) of extruded‐expelled soy flour protein (protein dispersibility index=21) that was poor in solubility and other functional properties was evaluated at pilot‐plant scale (5 kg of flour) with two endopeptidases and one exopeptidase. Some hydrolysates were merely spray‐dried whereas others were jet‐cooked at 104°C for 19 s before spray‐drying. Solubility, emulsification capacity and stability, foaming capacity and stability, apparent viscosity, and sensory attributes were then characterized. The type of protease used and hydrothermal cooking affected functional and sensory properties. Protein solubility modestly increased with hydrolysis and jet cooking, but emulsification capacity decreased on hydrolysis and was not restored with hydrothermal cooking. Emulsion stability improved in the endopeptidase hydrolysates, but not in the exopeptidase hydrolysates. The foaming capacities of the hydrolysates for both types of enzymes were better than for the unhydrolyzed control. Highly stable foams were obtained after hydrolyzing with exopeptidase and hydrothermal cooking. Ten percent protein hydrolysate dispersions showed large losses in consistency coefficient apparent viscosity, which increased significantly with hydrothermal cooking only for the unhydrolyzed control. Difference‐from‐control sensory evaluation indicated that both jet‐cooked and non‐jet‐cooked enzyme hydrolysates were different from unhydrolyzed controls.
Modification of the Avrami model for application to the kinetics of the melt crystallization of lipids
Authors: Narine Suresh S. , Humphrey Kerry L. , Bouzidi Laziz
Published: February 2007

The Avrami model was developed to model the kinetics of crystallization and growth of a simple metal system. The original assumptions of the model do not apply for high‐volume‐fraction crystallizing lipids, although it is incorrectly and frequently applied. A modified form of the Avrami model, wellsuited to complex lipid crystallization kinetics, is developed. It produces excellent fits to experimental data and allows the prediction of physically meaningful parameters, such as changes in nucleation rate and type, growth rate, morphology, and dimensionality. Morphological changes highlighted by time‐resolved temperature‐controlled polarized light microscopy support its application to crystallizing lipids. The kinetics of crystallization for six separate lipid samples were monitored by pulsed NMR, and fits were performed using the classical and modified Avrami model. In all cases, the modified model provided superior fits to the data compared with that of the classical model. The modified model supports the theory that lipids crystallize and grow into networks via very specific growth modes. Furthermore, the case is made that it is useful for interpreting crystallization kinetics of other systems such as polymer melts, which have nonconstant growth rates, dimensionalities, and nucleation conditions, and whose growth become diffusion‐limited within specific regimes.
Optimization of enzymatic methanolysis of soybean oil by response surface methodology
Authors: Demirkol Seda , Aksoy H. Ayse , Tüter Melek , Ustun Guldem , Sasmaz Dursun Ali
Published: February 2007

Enzymatic methanolysis of refined soybean oil with methanol was investigated using Rhizomucor miehei lipase, Lipozyme RM IM, in n‐hexane for reaction times of 30 min. Response surface methodology (RSM) based on three‐level, three‐factor (variable) face‐centered cube design was used for the optimization of methanolysis. The independent variables that affect the methanolysis reaction conducted in n‐hexane are temperature (°C), enzyme/oil weight ratio, and oil/methanol molar ratio. A good quadratic model was obtained for the methyl ester production by multiple regression and backward elimination. A linear relationship was observed between the observed and predicted values (R2−0.9635). The effects of temperature and enzyme amount, which affected methyl ester content of the product (response) positively, were significant (P<0.01). The quadratic term of temperature and the interaction term of enzyme amount with temperature affected the response negatively (P<0.01). The interaction term of enzyme amount with substrate mole ratio had a positive effect on the response (P<0.05). Critical conditions for the response at which methyl ester content of the product was 76.9% were determined to be 50°C, 2.37 methanol/oil mole ratio, and 0.09 enzyme/oil weight ratio.
Effect of the level of iodine in the diet of pregnant ewes on the concentration of immunoglobulin G in the plasma of neonatal lambs following the consumption of colostrum
Authors: Rose Michael T. , Wolf Basil T. , Haresign William
Published: February 2007

Excessive I in the diet of pregnant sheep can reduce the concentration of antibodies in the blood plasma of the lambs after they have consumed colostrum. Our aim was to determine the dose of dietary I that would avoid this effect, and to relate this to changes in the concentrations of hormones and metabolites in the lambs. Four groups of pregnant ewes received concentrate containing 5·5, 9·9, 14·8, and 21·0 mg I/kg DM, respectively. Hay and molasses (containing 0·16 and 0·29 mg I/kg DM, respectively) were available ad libitum. The lambs were prevented from suckling for the first 24 h of life and were fed a fixed quantity of artificial colostrum in four feeds. At 24 h, the average plasma concentrations of immunoglobulin G in the lambs were 6·08, 5·06, 3·18 and 3·10 g/l for the 5·5, 9·9, 14·8 and 21·0 mg/kg groups, respectively. Supplementation with I was associated with higher levels of tri-iodothyronine and thyroxine in the lambs at birth. There was no effect of treatment on the plasma concentrations of insulin, cortisol, glucose or NEFA in the lambs. The concentration of dietary I that had an effect on the immunoglobulin concentration in the lambs is marginally above the levels added to commercial concentrate feeds; we tentatively identify 9·9 mg I/kg DM (approximately 9 mg I/ewe per day) as the upper safe limit of I supplementation according to the criterion of the concentration of immunoglobulin G in the plasma of lambs at 24 h after birth.
Biotype status and genetic polymorphism of the whiteflyBemisia tabaci(Hemiptera: Aleyrodidae) in Greece: mitochondrial DNA and microsatellites
Authors: Tsagkarakou A. , Tsigenopoulos C.S. , Gorman K. , Lagnel J. , Bedford I.D.
Published: February 2007

The genetic polymorphism and the biotype identity of the tobacco whiteflyBemisia tabaci(Gennadius) have been studied in population samples taken from different localities within Greece from cultivated plants growing in greenhouses or in open environments and from non-cultivated plants. Two different approaches were used: sequencing of the mitochondrial cytochrome oxidase I (mtCOI) gene and genotyping using microsatellite markers. Analyses of the mtCOI sequences revealed a high homogeneity between the Greek samples which clustered together with Q biotype samples that had been collected from other countries. When genetic polymorphism was examined using six microsatellite markers, the Greek samples, which were all characterized as Q biotype were significantly differentiated from each other and clustered into at least two distinct genetic populations. Moreover, based on the fixed differences revealed by the mtCOI comparison of knownB. tabacibiotype sequences, two diagnostic tests for discriminating between Q and B and non-Q/non-B biotypes were developed. Implementation of these diagnostic tools allowed an absence of the B biotype and presence of the Q biotype in the Greek samples to be determined.
BESSEL- AND GRÜSS-TYPE INEQUALITIES IN INNER PRODUCT MODULES
Authors: Banić Senka , Ilišević Dijana , Varošanec Sanja
Published: February 2007

In this paper we give Bessel- and Grüss-type inequalities in an inner product module over a proper $H^*$-algebra or a $C^*$-algebra.