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991.
992.
Januário AH Lourenço MV Domézio LA Pietro RC Castilho MS Tomazela DM da Silva MF Vieira PC Fernandes JB França Sde C 《Chemical & pharmaceutical bulletin》2005,53(7):740-742
Crude extracts of callus and roots of Dipteryx odorata were analyzed by HPLC to detect and quantify isoflavone contents. Based on spectroscopic and X-ray crystallography data the structures of two isoflavones were elucidated as 7-hydroxy-4',6-dimethoxyisoflavone and 3',7-dihydroxy-4',6-dimethoxyisoflavone. The production of dry biomass of 7-hydroxy-4',6-dimethoxyisoflavone in cultured callus was 4.12 mg/g, approximately eleven fold higher than the amount accumulated in roots of D. odorata wild-growing plants. The 7-hydroxy-4',6-dimethoxyisoflavone was effective against glyceraldehyde-3-phosphate dehydrogenase from Trypanosoma cruzi. This is the first report on those bioactive isoflavones accumulated in callus of D. odorata. 相似文献
993.
Nataly A. Santos Marileide L. A. Tavares R. Rosenhaim F. C. Silva V. J. Fernandes Jr Iêda M. G. Santos A. G. Souza 《Journal of Thermal Analysis and Calorimetry》2007,87(3):649-652
The growing petroleum deficit
requires the development of alternative fuel sources. Biodiesel is a good
alternative, as it is a biodegradable and renewable product, which obeys the
carbon cycle. In this work, the biodiesel from babassu was synthesized using
the methanol route, and characterized by physico-chemical analyses in order
to make able the investigated biodiesel to fulfill with its properties the
requirements of Brazilian National Agency for Petroleum, Natural Gas and Biofuel
(ANP). Besides gas chromatography, IR spectroscopy experiments and thermoanalytical
measurements in air and in nitrogen were done to determine the main thermal
decomposition processes and calorimetric events. The evaporation temperature
of babassu biodiesel was similar in both atmospheres, started around 52 in
air and around 60°C in nitrogen. 相似文献
994.
995.
Piedade JA Fernandes IR Oliveira-Brett AM 《Bioelectrochemistry (Amsterdam, Netherlands)》2002,56(1-2):81-83
Adriamycin, a cancerostatic anthracycline antibiotic, causes considerable death of tumour cells, together with the induction of breaks in DNA single and double strands. The interaction of this compound with DNA was investigated using an electrochemical DNA-biosensor. Adriamycin intercalation in DNA disrupts the double helix and the detection of guanine and 8-oxoguanine could mimic one possible mechanism for the in vivo adriamycin drug action. 相似文献
996.
Roberto S. Fernandes Gaspar González Elizabete F. Lucas 《Colloid and polymer science》2005,283(4):375-382
Oil-in-water emulsions are usually formed during oil production and treatment. Before being discarded, such dispersions should be treated. In order to improve the oil–water separation process using physical processes (decantation, flotation, centrifugation, etc.) the particle size of the disperse phase should be increased. This may be achieved through flocculation, which consists in the agglomeration of various particles or drops, using, as flocculating agents, high molecular weight hydrophilic macromolecules. A few studies have been carried out on the flocculation of finely divided oil drops in brine with the aid of generally ionic polyelectrolytes. This work shows the results obtained using nonionic polymers as flocculants. Commercial samples of poly(ethylene oxide-b-propylene oxide) and poly(vinyl alcohol) were evaluated through flocculation–flotation tests as well as the drop size distribution. The performance of such additives as flocculants for oil–water dispersions is related to their structure, composition, molecular weight and hydrophilic–lipophilic balance. The composition of the produced water is also an important parameter when choosing the features of the flocculant additive. 相似文献
997.
Dalci José Brondani Diogo Rodrigo de Magalhães Moreira Maria Patrícia A. de Farias Flávio Ricardo da S. Souza Fábio Fernandes Barbosa Ana Cristina Lima Leite 《Tetrahedron letters》2007,48(22):3919-3923
An easy to perform and regioselective synthesis of N-alkyl hydrazones/hydrazides is described, which uses an aprotic medium with kinetic control. This procedure produced the desired monoalkylated or dialkylated amines with excellent yields and selectivities. 相似文献
998.
F. S. Tagliaferro E. A. De Nadai Fernandes M. A. Bacchi 《Journal of Radioanalytical and Nuclear Chemistry》2006,269(2):371-375
Summary A random sampling was carried out in the coffee beans collected for the preparation of the organic green coffee reference
material in view of assessing the homogeneity and the presence of soil as impurity. Fifteen samples were taken for the between-sample
homogeneity evaluation. One of the samples was selected and 10 test portions withdrawn for the within-sample homogeneity evaluation.
Br, Ca, Co, Cs, Fe, K, Na, Rb, Sc and Zn were determined by instrumental neutron activation analysis (INAA). The F-test demonstrated that the material is homogeneous for Ca, Co, Cs, K and Sc, but not homogeneous for Br, Fe, Na, Rb and Zn.
Results of terrigenous elements suggested negligible soil contamination in the raw material. 相似文献
999.
In this work, the thermotropic liquid crystal MBBA (N-(4-methoxybenzilidene)-4-butylaniline), entrapped on hydrogels, based on cross-linked polyacrylamide (PAAm), was studied. The liquid crystalline phases of system were characterized by polarized optical microscopy (POM), refractive index, optical transmittance, scanning electron microscopy (SEM) and water loss. It was verified the presence of birefringence on hydrogel + liquid crystal. The dynamic of formation of such birefringence finished 40 days after the hydrogel synthesis. The effective birefringence Δn, i.e., the difference on refractive index of polyacrylamide hydrogel to refractive index of hydrogel + liquid crystal (Δn1) and the difference on refractive index of liquid crystal (MBBA) to refractive index of hydrogel + liquid crystal (Δn2) are dependent of content of acrylamide (AAm) and MBBA on hydrogel. The increase on Δn1 and Δn2 with the polyacrylamide content on hydrogel was attributed to decreasing of the mobility liquid crystal inside the hydrogel. Also, an increase on MBBA concentration in the polymeric matrix provides a reduction in the values of optical transmittance in the system. The morphology observed by SEM shows that hydrogel + liquid crystal is more compact that PAAm hydrogels. The presence of MBBA causes an increase in hydrophobicity. The water loss speed is favored by the increase in the amount of MBBA present in the hydrogels. 相似文献
1000.
We present a general derivation of the Duffin-Kemmer-Petiau (D.K.P) equation on the relativistic phase space proposed by Bohm and Hiley. We consider geometric algebras and the idea of algebraic spinors due to Riesz and Cartan. The generators
(p) of the D.K.P algebras are constructed in the standard fashion used to construct Clifford algebras out of bilinear forms. Free D.K.P particles and D.K.P particles in a prescribed external electromagnetic field are analized and general Liouville type equations for these cases are obtained. Choosing particular values for the label p we classify the different types of the D.K.P Liouville operators. 相似文献