Protection of biodiesel based on sunflower oil from oxidative degradation by natural antioxidants

Biodiesel as an alternative diesel fuel obtained by transesterification of vegetable fats and oils, using alcohol in the presence of a catalyst, has some advantages such as reduced emissions of unburned hydrocarbons, carbon monoxide, sulfates, polycyclic aromatic hydrocarbons, and particular matter but its drawback, of being more prone to oxidation than petroleum-based diesel fuel, can cause the fuel to become acidic (cause fuel system corrosion) and to form insoluble gums and sediments and consequently increase its viscosity. In this study, in order to increase the stability of biodiesel based on high oleic acid sunflower oil against oxidation process during the storage and distribution, different percents S0.01%, 0.02%, 0.05%, 0.1%, and 0.2% (w/v)C of maize flour contaminated by mycotoxins, thus useless for human consumption, were added as natural antioxidants. The antioxidant effect increased with concentration up to an optimal level. Above the optimal level the increase in antioxidant effect with its concentration was relatively small. Oxidative stability of biodiesel was determined using two parallel methods, the Schaal oven storage test (at 70°C) and the Rancimat method (at 110°C). The induction times obtained by the Rancimat method were more similar to the values determined by the oven test. The highest protective effect was observed in samples containing 0.1% (w/ v) of added antioxidants

Half-Seed Analysis for Comparing Linolenic Acid Synthesis Between High and Low Oleic Acid Sunflower Inbred Lines

The modification of fatty acid composition of two sunflowers inbred lines, HA89 and R978, low oleic acid (normal) and high oleic acid (mutant) respectively, in seeds and during the first stages of growth (A1-B2) was studied under controlled conditions. Enzymatic mechanisms have great effect on the catabolism of seed stored lipids. Temperature and oxygen regulation influence developing sunflower seeds. For simultaneous study of seed and developing seed, half-seed analysis technique was used. The behavior of the fatty acids during the germination in cotyledon of seed showed the increase of linolenic acid in both lines, demonstrating the activity of linoleic acid desaturase (\uc46-desaturase). But linoleic acid as a substrate for linoleate desaturase increased during all stages of developing only in mutant line that revealed higher activity of oleic acid desaturase (\uc412-desaturase) in transforming oleic acid to linoleic acid in this line, and lower activity of this enzyme in low oleic acid line, the reasons probably being the low availability of substrate of this enzyme in low oleic acid line and the complexity of enzymatic mechanisms. The modification of fatty acids in developing sunflower, depends not only on ambient conditions such as temperature and oxygen regulation as described by many authors, but also on the genotype. \ua9 2004, by Walter de Gruyter Berlin/Boston. All rights reserved

Property and Shape Modulation of Carbon Fibers Using Lasers

An exciting challenge is to create unduloid-reinforcing fibers with tailored dimensions to produce synthetic composites with improved toughness and increased ductility. Continuous carbon fibers, the state-of-the-art reinforcement for structural composites, were modified via controlled laser irradiation to result in expanded outwardly tapered regions, as well as fibers with Q-tip (cotton-bud) end shapes. A pulsed laser treatment was used to introduce damage at the single carbon fiber level, creating expanded regions at predetermined points along the lengths of continuous carbon fibers, while maintaining much of their stiffness. The range of produced shapes was quantified and correlated to single fiber tensile properties. Mapped Raman spectroscopy was used to elucidate the local compositional and structural changes. Irradiation conditions were adjusted to create a swollen weakened region, such that fiber failure occurred in the laser treated region producing two fiber ends with outwardly tapered ends. Loading the tapered fibers allows for viscoelastic energy dissipation during fiber pull-out by enhanced friction as the fibers plough through a matrix. In these tapered fibers, diameters were locally increased up to 53%, forming outward taper angles of up to 1.8°. The tensile strength and strain to failure of the modified fibers were significantly reduced, by 75% and 55%, respectively, ensuring localization of the break in the expanded region; however, the fiber stiffness was only reduced by 17%. Using harsher irradiation conditions, carbon fibers were completely cut, resulting in cotton-bud fiber end shapes. Single fiber pull-out tests performed using these fibers revealed a 6.75-fold increase in work of pull-out compared to pristine carbon fibers. Controlled laser irradiation is a route to modify the shape of continuous carbon fibers along their lengths, as well as to cut them into controlled lengths leaving tapered or cotton-bud shapes

Primary recovery factor as a function of production rate: implications for conventional reservoirs with different drive mechanisms

This study evaluates the dependency of production rate on the recovery of hydrocarbon from conventional reservoirs using MBAL simulator. The results indicated that the recoveries are sensitive to the production rate in almost all hydrocarbon reservoirs. It was also found that the recovery of volumetric gas drive reservoirs is not impacted by the production rate. In fact, any increase in the production rate improves gas recovery in weak and strong water drive reservoirs. Moreover, increasing the production rate in oil reservoirs decreases the recovery with a significant effect observed in the weak water drive reservoirs. The results of this study demonstrate the need for implementing an effective reservoir management in order to obtain a maximum recovery

Seroprevalence of Immunoglobulin G antibodies against pertussis toxin among asymptomatic medical students in the west of Iran: a cross sectional study

<p>Abstract</p> <p>Background</p> <p>Pertussis is a highly communicable, vaccine-preventable respiratory infection. Immune response against this disease can be induced by infection or vaccination. Protection after childhood vaccination is minimal after ten years. Our aim was to assess pertussis immunity state in a population of healthy young medical students.</p> <p>Methods</p> <p>In this seroepidemiological survey, blood samples were obtained from 163 first-year medical students in Hamedan University, Iran. Serum level of IgG against pertussis toxin (IgG-PT) was measured by Enzyme-Linked Immunosorbent Assay (ELISA) method. For qualitative assessment, IgG-PT levels more than 24 unit (U)/ml were considered positive. Data was analysed qualitatively and quantitatively considering gender and age groups.</p> <p>Results</p> <p>There were 83 males and 80 females, with a mean age of 19.48 years, Prevalence of IgG-PT was 47.6% with mean level of 71.7 u/ml (95% confidence interval: 68.1–75.3). No statistically significant difference was observed with respect to sero-positivity of IgG-PT between males and females (45 cases (54%) vs. 34 cases (42%); P = 0.06). Mean IgG-PT levels in males and females were 84 U/ml and 58.8 U/ml, respectively (P = 0.91).</p> <p>Conclusion</p> <p>A considerable proportion of our study population with a positive history of childhood vaccination for pertussis was not serologically immune to pertussis. A booster dose of acellular pertussis vaccine may be indicated in Iranian, medical students regarding their serologic conditions and outstanding role in health care systems.</p

Construction of an almond linkage map in an Australian population Nonpareil × Lauranne

Background: Despite a high genetic similarity to peach, almonds (Prunus dulcis) have a fleshless fruit and edible kernel, produced as a crop for human consumption. While the release of peach genome v1.0 provides an excellent opportunity for almond genetic and genomic studies, well-assessed segregating populations and the respective saturated genetic linkage maps lay the foundation for such studies to be completed in almond. Results: Using an almond intraspecific cross between ‘Nonpareil’ and ‘Lauranne’ (N × L), we constructed a moderately saturated map with SSRs, SNPs, ISSRs and RAPDs. The N × L map covered 591.4 cM of the genome with 157 loci. The average marker distance of the map was 4.0 cM. The map displayed high synteny and colinearity with the Prunus T × E reference map in all eight linkage groups (G1-G8). The positions of 14 mapped gene-anchored SNPs corresponded approximately with the positions of homologous sequences in the peach genome v1.0. Analysis of Mendelian segregation ratios showed that 17.9% of markers had significantly skewed genotype ratios at the level of P < 0.05. Due to the large number of skewed markers in the linkage group 7, the potential existence of deleterious gene(s) was assessed in the group. Integrated maps produced by two different mapping methods using JoinMap® 3 were compared, and their high degree of similarity was evident despite the positional inconsistency of a few markers. Conclusions: We presented a moderately saturated Australian almond map, which is highly syntenic and collinear with the Prunus reference map and peach genome V1.0. Therefore, the well-assessed almond population reported here can be used to investigate the traits of interest under Australian growing conditions, and provides more information on the almond genome for the international community.Iraj Tavassolian, Gholmereza Rabiei, Davina Gregory, Mourad Mnejja, Michelle G Wirthensohn, Peter W Hunt, John P Gibson, Christopher M Ford, Margaret Sedgley, and Shu-Biao W

The effects of long-term saturated fat enriched diets on the brain lipidome

The brain is highly enriched in lipids, where they influence neurotransmission, synaptic plasticity and inflammation. Non-pathological modulation of the brain lipidome has not been previously reported and few studies have investigated the interplay between plasma lipid homeostasis relative to cerebral lipids. This study explored whether changes in plasma lipids induced by chronic consumption of a well-tolerated diet enriched in saturated fatty acids (SFA) was associated with parallel changes in cerebral lipid homeostasis. Male C57Bl/6 mice were fed regular chow or the SFA diet for six months. Plasma, hippocampus (HPF) and cerebral cortex (CTX) lipids were analysed by LC-ESI-MS/MS. A total of 348 lipid species were determined, comprising 25 lipid classes. The general abundance of HPF and CTX lipids was comparable in SFA fed mice versus controls, despite substantial differences in plasma lipid-class abundance. However, significant differences in 50 specific lipid species were identified as a consequence of SFA treatment, restricted to phosphatidylcholine (PC), phosphatidylethanolamine (PE), alkyl-PC, alkenyl-PC, alkyl-PE, alkenyl-PE, cholesterol ester (CE), diacylglycerol (DG), phosphatidylinositol (PI) and phosphatidylserine (PS) classes. Partial least squares regression of the HPF/CTX lipidome versus plasma lipidome revealed the plasma lipidome could account for a substantial proportion of variation. The findings demonstrate that cerebral abundance of specific lipid species is strongly associated with plasma lipid homeostasis