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101.
Advances in our knowledge of the physiological functions of dietary polyunsaturated fatty acids (PUFAs) have led to an increased interest in food sources and the level of dietary intake of these nutrients. Up to now, no representative data was available for the Belgian adult population. This study aimed to describe data on the intake and food sources of total and individual omega-6 and omega-3 PUFA for the Belgian population over 15 years old. PUFA intakes were assessed for 3,043 Belgian adults, based on two non-consecutive 24 h recalls. Usual intakes were calculated using the multiple source method. The results showed that the intake of linoleic acid (LA) is in accordance with the recommendation for almost all Belgian adults. However, the intake of omega-3 PUFA is suboptimal for a large part of the studied population and also the intake of total PUFA should be increased for a part of the population. The main food source of LA and α-linolenic acid (ALA) was the group of fats and oils (60.6 % for LA and 53.1 % for ALA). Fish and fish products were the most important sources of long chain omega-3 PUFA. Age influenced fatty acids intake, with higher intake of omega-3 PUFA in the older age groups. To fill the gap between the intake and recommendation of total PUFA, and in particular omega-3 PUFA, sustainable strategies and efficient consumer communication strategies will be needed.  相似文献   
102.
This paper compares the moisture diffusion properties of organomodified (Indian Bentonite nanoclay)/vinylester containing different amounts of nanoclay on exposure to demineralized water and artificial seawater at room temperature. Moisture uptake behavior of (Indian Bentonite)/vinylester was investigated and compared with that of neat vinylester. Addition of 5 wt% nanoclay decreased the diffusivity and permeability of vinylester in artificial seawater medium, but these diffusion parameters increased in demineralized water medium. Degradation in glass transition temperature and microhardness of the nanocomposites were much greater in specimens aged in demineralized water than in those in artificial seawater medium. Moisture diffusion behavior of the specimens was analyzed by Fick's law and the Langmuir model. The aged specimens were chemically analyzed by using infrared spectroscopy after aging for 146 days. A significant amount of leached organic species was detected in the demineralized water–aged specimens but the same was absent in those aged in artificial seawater. J. VINYL ADDIT. TECHNOL., 22:441–451, 2016. © 2015 Society of Plastics Engineers  相似文献   
103.
Addition of water at levels of 0.25 to 1.00% (wt/vol) to raw peanut oil inhibited the formation of peroxides in the oil. The free fatty acid content of oils to which water had been added also did not increase appreciably compared to a control oil. To improve the stability of the oil, a moisture content of 0.2%, which is about ten times higher than the Brunauer-Emmett-Teller monomolecular moisture content of the oil, has been suggested.  相似文献   
104.
Blending and interesterification of cold‐pressed oil from commercially available niger (Guizotia abyssinica (L.f.) Cass.) seeds was performed to improve its stability. The fatty acid composition of cold‐pressed niger seed oil (NSO) revealed that it contained a huge amount of polyunsaturated linoleic acid (69.2 %). NSO being rich in polyunsaturated fatty acids (PUFA) was susceptible to oxidation and hence was blended with saturated fatty acid (SFA) rich coconut oil (CNO) and monounsaturated fatty acid (MUFA) rich olive–pomace oil (OO) to enhance its stability. CNO contained a total of 91.3 % of SFA, while OO had oleic acid, C18:1 (74.3 %) as MUFA. Two blends of NSO with CNO and OO, i.e. NSO + CNO(B) and NSO + OO(B), were prepared in the ratio of 1:1. The blends were further interesterified using the lipase enzyme from Rhizomucor meihei and interesterified oils, i.e. NSO + CNO(I) and NSO + OO(I), were obtained. The oxidative stability of the oils was evaluated by incubating them at 37 °C and 55 % relative humidity (RH) for a period of 45 days. The peroxide values of NSO + CNO(B), NSO + OO(B), NSO + CNO(I) and NSO + OO(I) showed a reduction by 53.3, 42.6, 65.3 and 55.4 %, respectively, while the conjugated diene values showed a reduction by 75.0, 66.9, 76.7 and 75.3 %, respectively, as compared to NSO during the incubation period. This is probably the first report on the stability improvement of niger seed oil through blending and interesterification.  相似文献   
105.
Electrodeposition of metals from solution is usually accompanied by the simultaneous discharge of hydrogen ions or water molecules. When hydrogen is liberated at an iron/steel surface during electrodeposition, a portion of the hydrogen is absorbed by the metal surface and then diffuses into the interior. The diffused hydrogen produces some detrimental effects, such as reduction in ductility and loss in mechanical strength, leading to hydrogen embrittlement. The present paper reports investigations on hydrogen permeation measurements in zinc-manganese alloy deposition using a modified electrode clamp for easy removal and fixing of the electrode. Hydrogen permeation studies indicate that the porosity of the deposit increases in the following order:Zn-Mn(14.3%), Zn-Mn(2.4%), Zn-Mn(24.8%) and Zn-Mn(37.5%).This is in agreement with the corrosion data obtained which indicates that Zn-Mn alloy deposits with low manganese content show better performance than pure zinc deposits.  相似文献   
106.
Performance analyses are carried out for the palladium membrane fuel processor for catalytic generation of high purity hydrogen. The reactor model includes detailed particle-scale multi-component diffusion, multiple reversible reactions, flow, and membrane transport. Using methanol steam reforming on Cu/ZnO/Al2O3 catalyst as the test reaction, a systematic examination of the effects of operating and reactor design parameters on key performance metrics is presented. Single particle simulations reveal a complex interplay between nonisobaric transport and the reversible reactions (methanol reforming and decomposition, and water-gas shift), which impact overall reactor performance. An analysis of characteristic times helps to identify four different productivity controlling regimes: (i) permeation control, encountered with thick membranes and/or insufficient membrane area; (ii) catalyst pore diffusion control encountered with diffusion of reacting species in larger particles; (iii) reaction control, encountered when intrinsic catalytic rates are too low because of inadequate activity or catalyst loading; and (iv) feed control, encountered when the limiting reactant feed rate is inadequate. The simulations reveal that a maximum in the hydrogen productivity occurs at an intermediate space velocity, while the hydrogen utilization is a decreasing function of space velocity, implying a trade-off between productivity and hydrogen utilization. The locus of productivity maxima itself exhibits a maximum at an intermediate membrane surface to volume ratio, the specific value of which is dependent on the particle size, membrane thickness and reaction conditions. At moderate temperature and total pressure (, 10 bar), particles smaller than 2 mm diameter, Pd membranes with thickness less than , and membrane surface to volume ratio exceeding are needed to achieve viable productivity . A comparison between the packed-bed membrane reactor and conventional packed-bed reactor indicates a modest improvement in the conversion and productivity due to in situ hydrogen removal.  相似文献   
107.
Nitrogen species, specifically, the fate and occurrence of organic nitrogen (ON) within a 4-stage Bardenpho process bioreactor producing low total nitrogen (TN) effluents were investigated in this study. The results showed release of ON in primary anoxic zone and no ON release in the first aerobic zone of the process. The research included investigation of biodegradability/bioavailability of wastewater-derived effluent dissolved ON (DON). The final-effluent DON utilization was evaluated by two different bioassay protocols in the presence and absence of nitrate. About 28–57% of the effluent DON was bioavailable/biodegradable. Bioavailable (to algae and bacteria) DON (ABDON) and biodegradable (to bacteria) DON (BDON) results did not show significant differences in terms of quantity, but DON utilization rates by ABDON (0.13 day−1) protocol were higher than that of the BDON (0.04 day−1) protocol in the nitrate-removal samples. As a result, ABDON requires a shorter time to exert the bioavailable fraction due to symbiotic relationship between algae and bacteria. In the nitrate-containing samples, it appears that nitrate competes with labile DON as a nitrogen source to microorganisms in both ABDON and BDON protocols. The first order decay rate of DON in the presence of nitrate was 0.11 day−1 and 0.02 day−1 for ABDON and BDON, respectively.  相似文献   
108.
Flavonoids are ubiquitous polyphenolic compounds in plants, long recognised for their health-promoting properties in humans. Methylated flavonoids have received increasing attention due to the potential of methylation to enhance medicinal efficacy. Recently, Eucalyptus species with high levels of the O-methylated flavanone pinostrobin have been identified. Pinostrobin has potential commercial value due to its numerous pharmacological and functional food benefits. Little is known about the identity or mode of action of the enzymes involved in methylating flavanones. This study aimed to identify and characterise the methyltransferase(s) involved in the regiospecific methylation of pinostrobin in Eucalyptus and thereby add to our limited understanding of flavanone biosynthesis in plants. RNA-seq analysis of leaf tips enabled the isolation of a gene encoding a flavanone 7-O-methyltransferase (EnOMT1) in Eucalyptus. Biochemical characterisation of its in vitro activity revealed a range of substrates upon which EnOMT1 acts in a regiospecific manner. Comparison to a homologous sequence from a Eucalyptus species lacking O-methylated flavonoids identified critical catalytic amino acid residues within EnOMT1 responsible for its activity. This detailed molecular characterisation identified a methyltransferase responsible for chemical ornamentation of the core flavanone structure of pinocembrin and helps shed light on the mechanism of flavanone biosynthesis in Eucalyptus.  相似文献   
109.
This paper describes the synthesis and spectral investigations of two amino derivatives of N-methyl-N-(2,4,6-trinitrophenyl)nitramine (tetryl). Also discussed are the results from thermal decomposition studies on the three explosives, viz. tetryl, 3-aminotetryl (3 AT) and 3,5-diaminotetryl (3,5 DAT) and preliminary work on the explosive properties of the last two compounds. The aminotetryls have been prepared by the amination of the corresponding chlorotetryls. The yield was 87% for 3 AT, but was only 33% for 3,5 DAT, probably due to steric crowding around the benzene nucleus. The mass spectra show interesting differences in the electron impact fragmentation patterns of the three tetryls with the M+ ion relative intensities following the order 3,5 DAT > 3 AT > tetryl, which could be due to (a) resonance stabilization and (b) hydrogen bonding effects. Evidence for the latter is also found in the infrared spectra of these compounds. Arrhenius kinetic parameters derived from thermal decomposition studies of the three compounds are presented and show that 3,5 DAT is thermally less stable than 3 AT. Explosive sensitiveness tests indicate that the diamino compound is the most sensitive, the trend being 3,5 DAT > 3 AT > tetryl. This is contrary to the generally found desensitizing influence of NH2 groups on the thermal stability and explosive sensitiveness of trinitroaromatic energetic molecules. Mechanisms to account for the observed thermal decomposition behaviour and explosive sensitiveness patterns are discussed.  相似文献   
110.
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