918 resultados para composition study


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Japanese cornmint, also known as menthol mint (Mentiza canadensis L. syn M. arvensis L.), is an essential oil crop cultivated in several countries in Asia and South America. The plant is currently the only commercially viable source for natural menthol as a result of the high concentration of menthol in the oil compared with other crops. The hypothesis of this study was that harvesting at regular intervals within a 24-hour period would have an effect on essential oil concentration and composition of Japanese cornmint grown at high altitude in northern Wyoming. Flowering plants were harvested every 2 hours on 7 to 8 Aug. and on 14 to 15 Aug. and the essential oil was extracted by steam distillation and analyzed by gas chromatography mass spectroscopy (GC-MS). The effects of harvest date (Harvest 1 and Harvest 2) and harvest time (12 times within a 24-hour period) were significant on oil concentration and yield of menthol, but only harvest date was significant on the concentration of menthol in the oil. The interaction effect of harvest date and harvest time was significant on water content and on the concentrations of menthol and menthofuran in the oil and on the yield of limonene, menthol, and menthofuran. Overall, the oil concentration in grams per 100 g dried material for the two harvests (1.26 and 1.45, respectively), the concentration of menthol in the oil (67.2% and 72.9%, respectively), and menthol yield (1066 to 849 mg/100 g dried biomass) were higher in plants at Harvest 2 as compared with plants at Harvest 1. The oil concentration was higher in plants harvested at 1100 HR or at 1300 am and lowest in the plants harvested at 1500 BR. Menthol yield was the highest in plants harvested at 1300 HR and lowest in the plants harvested at 0700 HR, 1900 am, or at 0300 HR. This study demonstrated that harvesting time within a 24-hour period and harvest date (maturity of the crop) may affect essential oil concentration and composition of Japanese cornmint grown at high altitude in northern Wyoming.

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'Native'spearmint (Mentha spicata L.) is one of the two spearmint species grown commercially in the United States and other countries for essential oil production. The two major constituents of spearmint oil are carvone and limonene. It is not known if the essential oil yield (content) and composition of spearmint oil are affected by diurnal variation, and when it would be the best time for harvesting flowering spearmints within a 24h period. Therefore, the objective of this study was to evaluate the effect of diurnal variation on yield and composition of spearmint 'Native'essential oil for the environmental conditions of Northern Wyoming, at elevation 1170 m above the sea level. The experiment was conducted on a 3-year old well established spearmint plantation. The harvest times were every 2 h within a 24-h period: 7:00 AM, 9:00 AM, 11:00AM, 1:00 PM, 3:00 PM, 5:00 PM, 7:00 PM, 9:00 PM, 11:00 PM, 1:00 AM, 3:00 AM, and 5:00 AM. Essential oil yield varied from 0.96 to 1.47 g of oil per 100 g of dry herbage; the maximum oil yield was obtained at 9:00 AM and the minimum at 7:00 PM. The concentration of carvone in the oil varied from 44.1% (at 1:00 PM) to 66.4% (at 9:00 PM) of the total oil. However, the yield of carvone (a function of oil yield and carvone concentration in the oil) was the highest at 3:00 AM and the lowest at 1:00 PM. The concentration of limonene (10.7-15.8% of the oil) was the highest at 7:00 PM and the lowest at 1:00 PM, whereas the yield of limonene was the highest at 9:00 PM. For best essential oil yields, flowering spearmint should be harvested at around 9:00 AM. However, to obtain oil with high carvone concentration, spearmint should be harvested at 9:00 PM. Harvests at 1:00 PM would result in spearmint oil with low concentrations of both carvone and limonene, and hence, should be avoided. (C) 2014 Elsevier B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Acalypha californica Benth., is a plant in the northwestern region from Mexico, commonly known as "cancer herb" and used in traditional medicine for treating cancer. In the present study we have investigated the antiproliferative activity of methanolic extract of A. californica and its fractions in cancer cell lines and phytochemical analysis and mechanism of apoptosis of the fractions with antiproliferative activity. The antiproliferative activity of methanol extract and its fractions of solvents were evaluated by MTT assay against the M12.A(k).C3.F6, RAW 264.7, HeLa and L929 cell lines. Active fractions were fractionated by molecular exclusion chromatography, HPLC and MPLC. The identification of compounds was performed by NMR and FIA-ESI-IT-MS/MS analysis. Apoptotic mechanism was analyzed by flow cytometry, determining the reduction in the mitochondrial membrane potential (JC-1) and the activity of caspases 3,8 and 9. Cell viability assays showed that the hexane fraction of the methanol extract of the plant has significant effects against cancer lines RAW 264.7 (IC50 = 52.08 +/- 1.06 mu g/mL) and HeLa (IC50 = 46.77 +/- 1.09 mu g/mL), the residual fraction showed a selective effect on cell lines M12.A(k).C3.F6 (IC50 = 59.90 +/- 1.05 mu g/mL), RAW 264.7 (IC50 = 58.93 +/- 1.26 mu g/mL) and HeLa (IC50 = 50.11 +/- 1.135 mu g/mL) compared to the control cell line L929 (IC50 = 100.00 +/- 1.09 mu g/mL). The chemical characterization of the active fractions allowed the identification of p-sitosterol and stigmasterol in hexane fraction and some phenolic acids, proanthocyanidins and flavonoids in the residual fraction. The methanol extract and hexane fraction reduces mitochondrial membrane potential significantly and activates caspases 3, 8 and 9. Because of the antiproliferative activity observed, our results provide a rational basis for the use of extracts of A. californica in treating various types of cancer in traditional medicine from Mexico. The extracts induce apoptosis via activation of caspases. (C) 2015 Elsevier B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Using an effective two-body interaction potential, a molecular dynamics study of the structural properties of amorphous ZrF4 phase is presented. The effective pair potential includes steric repulsion, Coulomb interaction due to charge transfer, and charge-dipole interaction due to the large electronic polarizability of anions. The results for structural correlations, such as pair distribution functions, coordination numbers, and bond angle distributions are presented. Excellent agreement is obtained by comparing experimental X-ray diffraction and the simulated static X-ray structure factor. © 1993.

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In this work we present a Raman study of PbZr1-xTi xO3 ceramics with composition values close to the morphotropic phase boundary region. The analysis of the Raman spectra leads to the determination of the monoclinic phase extension at different temperatures in a very good agreement with those determined by diffraction techniques. Therefore the obtained results show that Raman spectroscopy is a powerful and suitable technique to study structural phase transitions in PbZr 1-xTixO3. © 2002 Taylor & Francis.

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Macroalgal seasonality was studied monthly in a second-order stream in the north-west of São Paulo State, S.E. Brazil. Seasonal variation was based on frequency and percentage cover. Seven species were found during the study period, three of which ('Chantransia' stage of Sirodotia delicatula, Homoeothrix juliana and Klebsormidium subtile) were encountered throughout the year and showed well-defined seasonal patterns as well as the highest value of frequency and percentage cover. 'Chantransia' and H. juliana dominated in summer and fall, while for K. subtile winter was the most favourable period. The remaining species (Oscillatoria agardhii, Microcoleus subtorulosus, Oedogonium sp. and Chaetophora elegans) had no clear seasonal pattern, in addition to their low values of frequency and percentage cover. Individually, K. subtile correlated with higher number of physical and chemical variables (oxygen, pH, precipitation, temperature, daylength, conductance and turbidity) than 'Chantransia' and H. juliana (discharge and depth). Principal component analyses revealed that no single variable was responsible for the macroalgal seasonal dynamics. The variables most closely related to seasonal variation of the macroalgal community were daylength, precipitation, discharge, turbidity and dissolved oxygen. Precipitation and flow were suggested as key factors in determining seasonality of the macroalgae. © 1991 Kluwer Academic Publishers.

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The mechanism of electrochemical oxidation of surface reformed CuA1Ag alloys having different composition of heat treatment, in 0.5 M NaOH was studied by means of cyclic polarization, constant potential electrolysis, ICP, AA, SEM and EDX. The surface reformation consisted of a repetitive triangular potential sweep (RTPS) between H 2 and O 2 evolution at 100 mV s -1 in the working solution itself, performed in order to increase the electrode roughness and obtain a quasi-stationary I/E profile in which the potentiodynamic behaviour of copper and silver was clearly revealed. The alloys suffer aluminum dealloying after such an RTPS. The quasi-stationary cyclic polarization curve exhibits a multiplicity of current peaks which have been related to the electrochemical reactions involving the pure alloying elements. Complex potential perturbation programmes in regions having different anodic and cathodic limits allowed the study of the mechanism of the electrochemical oxidation of the surface reformed alloys and the compare with that corresponding to the pure metals. The basic differences between the electro-oxidation processes of the surface reformed CuA1Ag alloys with respect to those established for the high purity alloying metals are the splitting of the peaks corresponding to the formation of the Cu(I) and Ag(I) species. © 1991.

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The aim of this study was to verify the effects of running overtraining protocols performed in downhill, uphill, and without inclination on the proteins related to hypertrophy signaling pathway in extensor digitorum longus (EDL) and soleus of C57BL/6 mice. We also performed histological and stereological analyses. Rodents were divided into control (CT; sedentary mice), overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up), and overtrained by running without inclination (OTR). The incremental load, exhaustive, and grip force tests were used as performance evaluation parameters. 36 h after the grip force test, EDL and soleus were removed and immediately used for immunoblotting analysis or stored at -80°C for histological and stereological analyses. For EDL, OTR/down decreased the protein kinase B (Akt) and tuberous sclerosis protein 2 (TSC2) phosphorylation (p), and increased myostatin, receptor-activated Smads (pSMAD2-3), and insulin receptor substrate-1 (pIRS-1; Ser307/636). OTR/down also presented low and high relative proportions of cytoplasm and connective tissue, respectively. OTR/up increased the mammalian target of rapamycin (pmTOR), 70-kDa ribosomal protein S6 kinase 1 (pS6K1) and pSMAD2-3, and decreased pTSC2. OTR decreased pTSC2 and increased pIRS-1 (Ser636). For soleus, OTR/down increased S6 ribosomal protein (pS6RP) and pSMAD2-3, and decreased pIRS-1 (Ser639). OTR/up decreased pS6K1, pS6RP and pIRS-1 (Ser639), and increased pTSC2 (Ser939), and pSMAD2-3. OTR increased pS6RP, 4E-binding protein-1 (p4E-BP1), pTSC2 (Ser939), and pSMAD2-3, and decreased pIRS-1 (Ser639). In summary, OTR/down inhibited the skeletal muscle hypertrophy with concomitant signs of atrophy in EDL. The effects of OTR/up and OTR depended on the analyzed skeletal muscle type. J. Cell. Physiol. 9999: 1-12, 2015. © 2015 Wiley Periodicals, Inc.

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A structural study of CuO supported on a CeO2-TiO2 system was undertaken using X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) techniques. The results of XRD revealed the presence of only two phases, TiO2 anatase and CeO2 cerianite. A trend towards smaller TiO2 crystallites was observed when cerium content increased. When the amount of cerium increased, Ti K-edge XANES analysis showed an increasing distortion of Ti sites. The results of Ce LIII-edge EXAFS showed that Ce atoms are coordinated by eight oxygen atoms at 2.32 Å. For the sample containing a small amount of cerium, the EXAFS analysis indicated that the local structure around Ce atoms was highly distorted. The catalysts presented quite different Cu K-edge XANES spectra compared to the spectra of the CuO and Cu2O reference compounds. The Cu-O mean bond length was close to that of the CuO and the Cu atoms in the catalysts are surrounded by approximately four oxygen atoms in their first shell. Copper supported on the ceria-modified titania support catalysts displayed a better performance in the methanol dehydrogenation when compared to copper supported only on titania or on ceria. © 2002 Plenum Publishing Corporation.