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Amara Franko Kevin C. Seavey James Gumaer Wolfgang G. Glasser 《Cellulose (London, England)》2001,8(2):171-179
Thermoplastic composites were prepared using two continuous regenerated cellulose fiber types, rayon and lyocell, and with several different commercially-available thermoplastic cellulose esters as matrix. Matrix options included cellulose acetate propionate (CAP), and several cellulose acetate butyrates (CAB) with different butyryl content, having different molecular weights and different methods of plasticization (adipates and very low molecular weight cellulose ester fractions). Choice of cellulose ester type was generally found to have little or no effect on mechanical properties. A significant effect, however, was revealed for fiber type. The lyocell-based composites thereby were reflective of the greater stiffness of a fiber produced from anisotropic solution state. Their modulus consistently exceeded 20GPa whereas the rayon fiber-based composites had moduli between 6 and 8GPa. The latter, however, possessed failure strains that were 3 to 4 times greater than their stiffer counterparts. 相似文献
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Dietary exposure of Thais to pesticides during 1989-1996 总被引:1,自引:0,他引:1
Vongbuddhapitak A Atisook K Thoophom G Sungwaranond B Lertreungdej Y Suntudrob J Kaewklapanyachareon L 《Journal of AOAC International》2002,85(1):134-140
To monitor the exposure of the Thai to pesticide residues in foods, the intake of pesticides based on the total diet approach has been studied in Thailand continually since 1989. Food items were chosen and their proportions of daily consumption were calculated from the national food consumption survey conducted by the Department of Health in 1986. Seventy-seven items of food including drinking water were classified into 12 groups according to their sources of contamination and the analytical methods used. Shopping lists and standard procedures for collecting samples and cooking were developed. Twelve food composites from each of the 4 regions were analyzed for nearly 100 pesticides. All analyses used multiresidue analytical methods, and the total daily dietary intakes of pesticide residues were estimated from the average amount of food consumed by Thais. Among 24 pesticides found in the 8 year study, DDT, dimethoate, methamidophos, and parathion methyl were found every year. However, dietary intakes of all pesticides were far below the established acceptable daily intake. In 1999, the study methodology was redesigned to accommodate the new national food consumption survey data. 相似文献
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Dr. M. John Plater Amara Darr Catriona Crawford Craig Murray Struan Simpson Prof. William T. A. Harrison Prof. Juan M. Clemente-Juan 《ChemistryOpen》2019,8(9):1204-1208
The synthesis of a Cu4(OH)4 cube which is coordinated by four molecules of the dipyridyl ligand 1,6-[di(pyridin-4-yl)hex-3-ene] is reported. This compound has a trans double bond which restricts the conformational freedom of the ligand and favours coordination within a unique copper cube. The structure was solved by an X-Ray single crystal structure determination and low temperature magnetic susceptibility measurements examined its magnetic properties. The cube classification corresponds to the type I classification of Mergehenn and Haase and the short/long distribution of Cu ⋅⋅⋅ Cu separations in the cube as defined by Ruiz. The magnetic susceptibility measurements show paramagnetic behaviour down to 50 K but below this the copper cube shows weak ferromagnetic exchange interactions. The low temperature magnetic susceptibility characteristics are examined in detail then modelled and compared to other similar Cu4O4 copper cubes. 相似文献
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In the paper, we study the problem on the number of zeros of eigenfunctions of the fourth-order boundary-value problem with
spectral and physical parameters in the boundary conditions. We show that the number of zeros of the eigenfunctions corresponding
to eigenvalues of positive type behaves in a usual way (it is equal to the serial number of an eigenvalue increased by 1),
but, however, the number of zeros of the eigenfunction corresponding to an eigenvalue of negative type can be arbitrary. In
the case of a sufficient smoothness of coefficients of the differential expression, we write the asymptotics in the physical
parameter for such a number.
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Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 12, No. 4, pp. 41–52, 2006. 相似文献
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Naima Benchikha Imane Chelalba Hanane Debbeche Mohammed Messaoudi Samir Begaa Imane Larkem Djilani Ghamem Amara Abdelkrim Rebiai Jesus Simal-Gandara Barbara Sawicka Maria Atanassova Fadia S. Youssef 《Molecules (Basel, Switzerland)》2022,27(12)
Lobularia libyca (L. libyca) is a traditional plant that is popular for its richness in phenolic compounds and flavonoids. The aim of this study was to comprehensively investigate the phytochemical profile by liquid chromatography, electrospray ionization and tandem mass spectrometry (LC-ESI-MS), the mineral contents and the biological properties of L. libyca methanol extract. L. libyca contains significant amounts of phenolic compounds and flavonoids. Thirteen compounds classified as flavonoids were identified. L. libyca is rich in nutrients such as Na, Fe and Ca. Moreover, the methanol extract of L. libyca showed significant antioxidant activity without cytotoxic activity on HCT116 cells (human colon cancer cell line) and HepG2 cells (human hepatoma), showing an inhibition zone of 13 mm in diameter. In silico studies showed that decanoic acid ethyl ester exhibited the best fit in β-lactamase and DNA gyrase active sites; meanwhile, oleic acid showed the best fit in reductase binding sites. Thus, it can be concluded that L. libyca can serve as a beneficial nutraceutical agent, owing to its significant antioxidant and antibacterial potential and due to its richness in iron, calcium and potassium, which are essential for maintaining a healthy lifestyle. 相似文献
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