bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstractβ‐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

AbstractThe 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

AbstractThe 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

AbstractThis 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

AbstractA 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

AbstractThe 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

AbstractThe 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

AbstractLong‐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

AbstractWe 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractLimited 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

AbstractThe 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

AbstractEnzymatic 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.