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71.
Subcellular fractions of nuclei, mitochondria, endoplasmic reticulum, plasma membrane and cytosol were prepared from liver
and hepatoma 72288CTC. Marker enzyme activities, biochemical compositions and electron microscopy were used to establish purity.
Hepatoma NADH: cytochrome C reductase and 5′-nucleotidase exhibited abnormal subcellular distributions.
The lipids from the subcellular fractions were examined in detail. Mitochondria and plasma membranes were characterized by
elevated percentages of diphosphatidylglycrerol and sphingomyelin, respectively, in both tissues. All hepatoma subcellular
fractions contained dramatically elevated levels of sphingomyelin and cholesterol, two components that form preferential strong
complexes in vitro. The fatty acid composition of hepatoma sphingomyelin differed markedlg from liver and, unlike liver, did
not exhibit organelle specific compositions. Some hepatoma lipid classes contained reduced percentages of palmitate while
others contained higher levels. Hepatoma phosphatidylcholine and phosphatidylethanolamine from organelles contained lower
percentages of long chain polyunsaturated fatty acids than liver. Generally, unique fatty acid profiles exhibited by individual
phospholipid classes of liver subcellular fractions were absent or much reduced in the hepatoma. The ratios of oleate to vaccenate
were near one for most of the phospholipid classes of most liver fractions, but all hepatoma classes, with few exceptions,
contained a much higher percentage of oleate in all subcellular fractions. The hypothesis is proposed that the origin of some
acyl moieties for the biosynthesis of various hepatome lipid classes differs from liver sources. The possible changes in acyl
pools, sources and compartments for complex lipid biosynthesis could result in change in the quantities of molecular species
that could contribute to the abnormal properties of the hepatoma membranes. 相似文献
72.
Luis Carlos da Silva Ramos Joao Shogiro Tango Angelo Savi Nilson Roberto Leal 《Journal of the American Oil Chemists' Society》1984,61(12):1841-1843
Thirty-six castorbean varieties were surveyed for oil and fatty acid composition, in order to determine variability of these
seed compounds. A large variability of seed oil percentage was observed, ranging from 39.6 to 59.5%. Concerning the fatty
acids, little variability was observed for ricinoleic acid, which was the most abundant in the oil, ranging from 83.65 to
90.00%. The other fatty acids appeared in small concentrations and showed a small range: 0.87 to 2.35, 0.68 to 1.84, 2.96
to 5.64, 3.19 to 5.98, and 0.34 to 0.91%, for palmitic, stearic, oleic, linoleic, and linolenic acid, respectively. Non-significant
correlations were observed between fatty acids and seed oil percentage. However, significant correlations were observed among
fatty acid concentrations: positive and negative ones. These significant correlations could be associated with the biosynthetic
pathways of the fatty acids, which are not fully elucidated. They suggest, however, that selection for a particular fatty
acid will tend to increase those positively correlated, and decrease those negative ones. Selection and plant breeding techniques
could then be applied to modify the oil content of the castorbean seeds, considering the variability observed. For the fatty
acid composition, however, the variability was not large enough to make substantial changes in their concentrations by selection
procedures. More varieties should be surveyed to find out if such variability is available. 相似文献
73.
Carlos Rivas-Costa Luis Anido-Rifón Miguel A. Gómez-Carballa Sonia Valladares-Rodríguez Roberto Soto-Barreiros 《International journal of human-computer interaction》2014,30(6):480-494
This article discusses a modular, accessible platform that provides a computing environment for people with disabilities accessible through adapted control devices and the television set at users’ homes. Relying on a standard television set as the presentation device allows dependent individuals, especially people with disabilities, to introduce new technological advances in communication and information management in their everyday lives. As a proof-of-concept, the solution presented offers a collection of educational and training services related to teleworking and the search of employment targeted to people with disabilities. A smart job advisor included among these services, which was designed to help our target users to locate job offers that best suit the abilities and disabilities of a particular individual, is also discussed to illustrate how semantic technologies can be applied to increase the perceived accessibility and inclusion by reducing the dependence from other persons. The platform developed, the introduction of semantic technologies, and the way adapted interfacing and presentation devices were integrated may also serve as inspiration to provide services to people with disabilities. 相似文献
74.
Roberto J. de Antueno Richard C. Cantrill Yung-Sheng Huang Michele Elliot David F. Horrobin 《Lipids》1993,28(4):285-290
This study was undertaken to investigate the total plasma fatty acid composition and the relationship between plasma triacylglycerol
(TG) levels and liver Δ9 desaturase activity in mice fed n−3 and/or n−6 fatty acid or hydrogenated coconut oil (HCO) (maximum
25 mg/g) supplemented diets. Generally, plasma TG levels and Δ9 desaturase activity were inversely correlated with the ratio
of the sum of long chain n−3 fatty acids to 18∶2n−6 and to the ratio of the sum of long chain n−3 fatty acids to 18∶n−3, but
they were positively correlated with the ratio of products and substrates (18∶1/18∶0) of the enzyme in plasma total lipids.
The n−3 fatty acid (mainly 20∶5n−3) enriched diet, when compared to the HCO diet at 21 d, caused a significant reduction in
plasma TG levels but not in Δ9 desaturase activity. However, a marked reduction in plasma TG content (50–60%) and Δ9 desaturase
activity (55–70%) was observed when both 20∶5n−3 and 18∶3n−6 were supplemented in the diet. The plasma TG levels and Δ9 desaturase
activity rose again when the animals were fed the HCO diet or chow. The results suggest that low dose supplementation of a
mixture of n−3 (mainly 20∶5n−3) and n−6 (18∶3n−6) fatty acids modified both plasma TG content and liver Δ9 desaturase activity,
in parallel. 相似文献
75.
Natália F. C. Vargas Mahmoud S. Alkathy José A. Eiras Valmor Roberto Mastelaro Manuel H. Lente 《Journal of the American Ceramic Society》2021,104(6):2600-2609
In this work, the influence of the sintering temperature on the physical properties of (Pb0.8La0.2)(Ti0.9Ni0.1)O3 (PLT-Ni) ceramics is reported. The experimental data revealed that the energy band gap of PLT-Ni ceramics could be tailored from approximately 2.7 to 2.0 eV by changing the sintering temperature from 1100°C to 1250°C. It is demonstrated that the simple substitution of Ti4+ by Ni2+ cations is effective to decrease the intrinsic band gap while increasing the tetragonality factor and the spontaneous polarization. However, the additional red-shift observed in the absorption edge of the PLT-Ni with increasing the sintering temperature was associated with a continuous increase in the oxygen vacancies () amount. It is believed that the impact of the creation of these thermally induced is manifold. The presence of and Ni2+ ions generate the Ni2+- defect-pairs that promoted both a decrease in the intrinsic band gap and an additional increase of the tetragonality factor, consequently, increasing the spontaneous polarization. The creation of Ni2+- defects also changed the local symmetry of Ni2+ ions from octahedral to a square pyramid, thus lifting the degeneracy of the Ni2+ 3d orbitals. With the increase in the sintering temperature, lower-energy absorbing intraband states were also formed due to an excess of , being responsible for an add-on shoulder in the absorption edge, extending the light absorption curve to longer wavelengths and leading to an additional absorption in “all investigated” spectrum as well. 相似文献
76.
Jairton Dupont Paulo A.Z. Suarez Alexandre P. Umpierre Roberto F. de Souza 《Catalysis Letters》2001,73(2-4):211-213
The combination of 1-n-butyl-3-methylimidazolium chloride with ZnCl2 affords ionic mixtures with different melting point temperatures depending on the zinc molar fraction. RuCl2(PPh3)3 immobilised in the low melting mixture (60°C) promotes the 1-hexene hydrogenation (turnover frequencies up to 44 min–1) and the recovered solid catalyst phase can be reused several times. 相似文献
77.
Polymer/carbon nanotube nanocomposites have attracted high interest for a wide spectrum of applications, including antistatic packaging used to protect electronic devices against electrostatic discharge. Polytrimethylene terephthalate (PTT)/maleic-anhydride-grafted PTT (PTT-g-MA)/acrylonitrile butadiene styrene (ABS) blend-based multiwall carbon nanotubes (MWCNTs) nanocomposites were prepared through extrusion. It was conducted chemical functionalization on the MWCNTs by oxidation using nitric acid to introduce functional groups. The effect of the amount (0.5 or 1.0 wt%) and functionalization of MWCNTs on the nanocomposites was investigated. Despite the poor barrier properties of PTT/PTT-g-MA/ABS/MWCNT nanocomposites due to the presence of voids confirmed by scanning electron microscopy (SEM), the nanocomposites with functionalized MWCNT (MWCNTf) showed excellent barrier properties, indicating that the functionalization process improved the interaction between the MWCNTs and the matrix. The addition of MWCNTs into PTT/PTT-g-MA/ABS blend decreased the electrical resistivity by eight orders of magnitude. The use of MWCNTf may still disrupt the electrical network pathway and slightly decreasing the electrical resistivity, but the nanocomposites present the desired properties required for antistatic packaging. 相似文献
78.
The effect of steric hindrance in the stress corrosion cracking (SCC) of Ag-15Pd (a/o) in AgI forming solutions was studied at room temperature. The solutions used were 1 M KI at a potential higher than that of AgI formation, and iodine dissolved in different n-alcohols. It was found that Ag-15Pd (a/o) is susceptible to intergranular stress corrosion cracking in those solutions. The SCC susceptibility measured as percentage of elongation to rupture and crack propagation rate is related to the size of the active species. While in KI aqueous solutions, as well as in iodine saturated benzene or iodine saturated toluene, the rate controlling step (RCS) was the reaction at the tip of the crack, in alcoholic-iodine solutions, the diffusion rate of the iodine containing molecules became the RCS. 相似文献
79.
Leonardo Roberto da Silva Eduardo Carlos Bianchi Ronaldo Yoshinobu Fusse Rodrigo Eduardo Catai Thiago Valle Frana Paulo Roberto Aguiar 《International Journal of Machine Tools and Manufacture》2007,47(2):412-418
The quality of machined components is currently of high interest, for the market demands mechanical components of increasingly high performance, not only from the standpoint of functionality but also from that of safety. Components produced through operations involving the removal of material display surface irregularities resulting not only from the action of the tool itself, but also from other factors that contribute to their superficial texture. This texture can exert a decisive influence on the application and performance of the machined component. This article analyzes the behavior of the minimum quantity lubricant (MQL) technique and compares it with the conventional cooling method. To this end, an optimized fluid application method was devised using a specially designed nozzle, by the authors, through which a minimum amount of oil is sprayed in a compressed air flow, thus meeting environmental requirements. This paper, therefore, explores and discusses the concept of the MQL in the grinding process. The performance of the MQL technique in the grinding process was evaluated based on an analysis of the surface integrity (roughness, residual stress, microstructure and microhardness). The results presented here are expected to lead to technological and ecological gains in the grinding process using MQL. 相似文献
80.
We consider an initial-boundary-value problem for a time-fractional diffusion equation with initial condition u0(x) and homogeneous Dirichlet boundary conditions in a bounded interval [0, L]. We study a semidiscrete approximation scheme based on the pseudo-spectral method on Chebyshev–Gauss–Lobatto nodes. In order to preserve the high accuracy of the spectral approximation we use an approach based on the evaluation of the Mittag-Leffler function on matrix arguments for the integration along the time variable. Some examples are presented and numerical experiments illustrate the effectiveness of the proposed approach. 相似文献