Stereospecific analysis of TAG from sunflower seed oil

Stereospecific analysis of TAG from a sunflower seed oil of Tunisian origin was performed. The TAG were first fractionated according to chain length and degree of unsaturation by RP-HPLC. The four major diacid- and triacid-TAG fractions were palmitoyldilinoleoyl-glycerol, dioleoyllinoleoylglycerol, oleoyldilinoleoylglycerol, and palmitoyloleoyl-linoleoyl-glycerol, amounting to 7.2, 16.6, 29.5, and 12 mol%, respectively. The TAG of the four fractions were individually submitted to stereospecific analysis, using a Grignard-based partial deacylation, separation of sn-1,2(2,3)-DAG from sn-1,3-DAG by boric acid-impregnated silica gel TLC plates, conversion of the sn-1,2(2,3)-DAG to their 3,5-dinitrophenylurethane (DNPU) derivatives, fractionation of DNPU derivatives by RP-HPLC, resolution of the DNPU-DAG by HPLC on a chiral column, transmethylation of each sn-DNPU-DAG fraction, and analysis of the resulting FAME by GC. The data obtained were used to determine the triacyl-sn-glycerol composition of the main TAG of the oil. Fifteen triacyl-sn-glycerols were identified and quantified, representing, along with the monoacid-TAG, trilinoleoylglycerol and trioleoylglycerol, more than 90% of the total oil TAG. The two major triacyl-sn-glycerols were trilinoleoyl-glycerol and 1-linoleoyl-2-linoleoyl-3-oleoyl-glycerol (18.6 and 18.5% of the total, respectively). Results clearly identified linoleic acid as the major FA at the sn-2 position, whereas oleic and palmitic acids were the major FA at the sn-3 position. The sn-1 position was occupied to nearly the same extent by linoleic and oleic acids, and to a greater extent by palmitic acid, which was practically absent at the sn-2 position.     

Electrochemical Oxidation of Ferulic Acid in Aqueous Solutions at Gold Oxide and Lead Dioxide Electrodes

A kinetic study of the electrochemical oxidation of ferulic acid (3-methoxy-4-hydroxycinnamic acid) by direct electron transfer at treated gold disk was combined with results of electrolyses in order to produce total degradation into CO₂ and H₂O at Ta/PbO₂ anode. The oxidation of ferulic acid at gold electrode was studied by cyclic voltammetry. At low concentration, ferulic acid shows one irreversible anodic peak. The peak current shows adsorption characteristics. For ferulic acid concentrations higher than 0.02 mmol dm⁻³, the voltammogram shows two anodic peaks. The effect of experimental conditions on the ratio of these two peaks was examined. The proposed mechanism is based on the hypothesis of two-electron oxidation of ferulic acid molecule involving a three intermediate cation mesomers. Hydrolysis of these mesomers leads to the formation of caffeic acid, methoxyhydroquinone and 3,4-dihydroxy-5-methoxycinnamic acid. Then ferulic acid was quantitatively oxidised by electrolysis on lead dioxide to produce, via intermediate aromatic compounds, maleic acid, oxalic acid and formic acid whose oxidation leads to carbon dioxide.     

Bundle and Pool Architecture for Multi-Language, Robust, Scalable Workflow Executions

In this paper, we leverage the previous work on the SHIWA bundling format and expand on this specification in order to facilitate workflow execution within a multi-workflow environment. We introduce a scalable and robust execution pool environment that supports workflows consisting of sub-workflows built upon a multitude of different workflow engines and environments, and also provide a common workflow representation for seamless connectivity through serialization to workflow bundles. We also present a meta-workflow scenario based upon this system. Workflow bundles employ the lightweight Open Archives Initiative Object Reuse and Exchange (ORE) Web-based standard, to provide a common format for representing and sharing workflows and the associated metadata required for their execution. This generalized bundling approach is already available within five workflow engines and has proven a useful environment for inter-workflow experimentation. The execution pool facilitates federated access to multiple distributed computing infrastructures supported by the underlying workflow engines subscribed to the pool. Workflow bundles are exposed using the eXtensible Messaging and Presence Protocol (XMPP), which provides the necessary communication backbone to enable multiple workflow engine agents to asynchronously publish and subscribe to bundles in meta-workflow pipelines. We present experiments showing the scalability and robustness of the pool execution approach with results showing that overheads remain controlled for up to 150 workflow agents, and that agent failures have very limited impact. We then demonstrate the applicability of our architecture by describing how a Java-based music analysis workflow can be distributed within such a multi-workflow environment consisting of the Triana and MOTEUR workflow engines.     

Compatibilization of PE/PS and PE/PP blends. I. Effect of processing conditions and formulation

The objective of this work was to study the effectiveness of low‐cost commercial compatibilizers and several processes (internal mixer, single‐ and twin‐screw extruders) for two types of plastic blends: high‐density polyethylene/polypropylene and high‐density polyethylene/polystyrene blends, to gain insight into the recycling of wastes from those frequently encountered mixed plastics. Blends going from a pure A to a pure B component, with and without a compatibilizer, were prepared using an internal mixer, a corotating twin‐screw extruder, as well as a single‐screw extruder to follow an industrial‐convenient process. In both cases, the analyses of blend morphologies highlighted the poor adherence between the two phases in the uncompatibilized blends. Compatibilized blends display better adherence between phases and the ability to process blends made from both single‐ and twin‐screw extruders. When adding a compatibilizer, the viscosity of each blend (PE/PP or PE/PS) increased due to a better adhesion of the phases. Charpy impact tests showed that the presence of the compatibilizer in PE/PS blends increased their impact properties. Indeed, the improvement of the adhesion between the two phases enabled stress transfer at the interface. A single‐screw extruder seems to be efficient as a processing method on an industrial scale when a compatibilizer is used. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2475–2484, 2003     

Kernel fatty acid and triacylglycerol composition for three almond cultivars during maturation

The kernel oil content, kernel FA and TAG composition, kernel moisture content, and kernel weight as well as fruit weight of three almond cultivars (Achaak, Mazetto, and Perlees) were monitored during the maturation of kernels. Lipid fractions of all almond samples were extracted using a mixture of chloroform and methanol. FAMF and TAG contained in these fractions were analyzed by GC and HPLC, respectively. The ratio of kernel to fruit weight appears to be a good indicator of almond kernel development. The total lipid content of developing almond kernels exhibited a sigmoidal pattern with time, similar to seeds and kernels of other higher plants; the cultivar Achaak showed a higher rate of lipid accumulation. The proportion of eleic acid (0) dominated at the later stage of maturation for all three almond cultivars. Although there was no significant difference in the FA composition for the three cultivars studied, marked differences were observed in their TAG profiles. Ten TAG species identified were LLL, LLO, LnOO, LOO, LOP, PLP, OOO, POO, POP, and SOO, where L represents linoleic acid; Ln, linolenic acid; P, palmitic acid; and S, stearic acid. The difference in the TAG profile can be useful for distinguishing various cultivars. The oil of Mazetto cultivar kernes exhibited a TAG composition comparable to that of olive oil.     

On The Stabilization of Homogeneous Perturbed Systems

In this paper, using some results on manifolds, we establish some conditions for stabilization of single-input homogeneous by dilation systems.      

Optimal use of Markov models for DPCM picture transmission over noisy channels

Joint source/channel decoders that use the residual redundancy in the source are investigated for differential pulse code modulation (DPCM) picture transmission over a binary symmetric channel. Markov sequence decoders employing the Viterbi algorithm that use first-order source statistics are reviewed, and generalized for decoders that use second-order source statistics. To make optimal use of the source correlation in both horizontal and vertical directions, it is necessary to generalize the conventional Viterbi decoding algorithm for a one higher-dimensional trellis. The paths through the trellis become two-dimensional "sheets", thus, the technique is coined "sheet decoding". By objective [reconstruction signal-to-noise ratio (SNR)] and subjective measure, it is found that the sheet decoders outperform the Markov sequence decoders that use a first-order Markov model, and outperform two other known decoders (modified maximum a posteriori probability and maximal SNR) that use a second-order Markov model. Moreover, it is found that the use of a simple rate-2/3 block code in conjunction with Markov model-aided decoding (MMAD) offers significant performance improvement for a 2-bit DPCM system. For the example Lenna image, it is observed that the rate-2/3 block code is superior to a rate-2/3 convolutional code for channel-error rates higher than 0.035. The block code is easily incorporated into any of the MMAD DPCM systems and results in a 2-bit MMAD DPCM system that significantly outperforms the noncoded 3-bit MMAD DPCM systems for channel-error rates higher than 0.04.     

A case-control study on the association of idiopathic recurrent pregnancy loss with autoantibodies against beta2-glycoprotein I and annexin V

Whereas antiphospholipid antibodies (aPL) are associated with thrombotic events and recurrent spontaneous abortion (RSA), the contribution of anti-beta2 glycoprotein 1 (beta2GP1) and anti-annexin V antibodies as risk factors for RSA remain poorly understood. We investigated anti-beta2-GPI and anti-annexin V IgM and IgG antibodies as potential risk factors for RSA in 200 women with more than three consecutive idiopathic RSA, and 200 age-matched, healthy, parous women. Pearson's chi squared test analysis showed that while anti-beta2-GPI IgG (P = 0.416) and IgM (P = 0.72) were comparable between patients and controls, elevated anti-annexin V IgG (P = 0.006), but not IgM (P = 0.084), was more pronounced in patients. Higher frequencies of elevated IgG-only (P = 0.005), but not IgM-only (P = 1.000; OR = 6.66), anti-annexin V antibodies were noted among patients. Multinomial regression analysis showed that body-mass index (overweight and obesity; P = 0.008), education status (P < 0.001) and anti-beta2-GPI IgM (P = 0.033), but not IgG (P = 0.723), were associated with early abortion, while anti-beta2-GPI IgG (P = 0.030) and anti-annexin V IgG (P = 0.004) were associated with late RSA. For combined early-late RSA, the only variable selected was education status (P < 0.001), and neither anti-annexin V nor anti-beta2-GPI IgM and IgG was associated with early-late RSA. Accordingly, anti-annexin V and anti-beta2-GPI should be regarded as independent risk markers of RSA.     

Sequential decoding with an efficient incremental redundancy ARQscheme

Sequential decoding is analyzed in conjunction with an efficient incremental redundancy automatic repeat request (ARQ) scheme using punctured convolutional coding. With the incremental redundancy ARQ scheme, whenever the decoding time of a given data packet exceeds some predetermined value T_max, decoding of that data packet is stopped and incremental redundancy bits are provided by the transmitter, a few bits at a time, as needed. It is shown that the incremental redundancy ARQ scheme provides throughput improvement over the partial retransmission code combining ARQ scheme. The advantage of the incremental redundancy ARQ scheme is that the throughput increases as the starting coding rate increases over all ranges of signal-to-noise ratios     

Three-dimensional tissue motion and its effect on image noise inelastography

In elastography both high correlation coefficient between pre- and post-compression RF signals and high applied strain are required to achieve the best quality in elastograms. Because the elastogram is computed using a 1-D cross-correlation technique applied to a 1-D ultrasound signal, it is assumed that tissue motion occurs only within the axis of compression (axis of the acoustic wave propagation), or at least that the scatterers remain within the acoustic beam during tissue motion. In practice, soft tissues are incompressible and, therefore, the lateral and elevational (out-of-plane) tissue strains are 50% of the applied strain. Therefore, tissue scatterers may move across the beam due to the applied compression. In this paper we address the degradation of the elastographic quality due to the lateral and elevational motion of the scatterers in uniformly elastic media. A full 3-D model predicting the correlation coefficient as measured using 1-D cross-correlations is proposed. It is shown that the signal-to-noise ratio in elastograms (SNR_e) is nonstationary, and that it depends on the beamwidth and on the applied strain. In order to achieve a higher stationary SNR_e, it is proposed to confine the tissue in the lateral direction. Phantom experiments are used to corroborate the theoretical developments