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121.
Marina Tavares Gregolin Bruna Galdorfini Chiari Helena M. Ribeiro 《Journal of Dispersion Science and Technology》2013,34(6):820-825
Rheological characteristics of gels were studied, with the focus on their use as a cosmetic base. Some ideal characteristics can be predicted by the rheological characterization, such as the performance, with easy application and without dripping or forming lumps and bubbles. Moreover, it is possible to detect signs of physical instability. The gels were prepared with sodium carboxymethyl cellulose 3% and 5%, with Carbopol 940 (INCI: Carbomer) and with Carbopol Ultrez (INCI: Acrylates/C10-30 alkyl acrylate crosspolymer). The tests performed were yield stress, stress sweep and creep and recovery. The gel with 3% of sodium carboxymethyl cellulose presented the most appropriated behavior and can be indicated as the most suitable cosmetic base. 相似文献
122.
Valeria FeliceAna C. Tavares 《Solid State Ionics》2011,194(1):53-61
In this work, the potential use of faujasite zeolites as a solid electrolyte material was evaluated with a particular focus on their endurance in acid environment, and on the influence played by the zeolites' chemical and textural properties on the degree of hydration and proton conductivity. Three faujasites with different initial Si/Al ratio were exposed to 6 mol dm−3 HCl solution and the exposure time was varied up to 7000 h for selected samples. Faujasite dealumination is a very fast process occurring mainly within 24 h of exposure. X-ray diffraction patterns show the faujasite structure was preserved, although N2 sorption measurements indicate a possible partial collapse of the pore structure for samples dealuminated for 4500 and 7000 h.The proton conductivity of the faujasites is in the order of 10−8 S cm-1 at 10% relative humidity, 10−6 S cm-1 at 90% relative humidity, and 10−4 S cm-1 for samples immersed in liquid water. The correlation between the proton conductivity and the zeolites' properties shows the predominant influence of the Al content at low relative humidity, and of the water content and micropore and mesopore volumes at high relative humidity. In particular, the expected increase of the proton conductivity with the mesopore volume at high relative humidity and for samples saturated with water was not observed. 相似文献
123.
Cleidjane Gomes Faustino Fernando Antnio de Medeiros Allan Kardec Ribeiro Galardo Alex Bruno Lobato Rodrigues Rosany Lopes Martins Yuri de Medeiros Souza Lima Josean Fechine Tavares Marcos Antnio Alves de Medeiros Jader dos Santos Cruz Sheylla Susan Moreira da Silva de Almeida 《Molecules (Basel, Switzerland)》2020,25(22)
The aim of this work was to prepare a nanoemulsion containing the essential oil of Protium heptaphyllum resin and to evaluate the larvicidal activity and the residual larvicidal effect against Aedes aegypti. The essential oil was identified by gas chromatography coupled to a mass spectrometer, and the nanoemulsions were prepared using a low-energy method and characterized by photon correlation spectroscopy. The results indicated the major constituents as p-cimene (27.70%) and α-Pinene (22.31%). Nanoemulsions had kinetic stability and a monomodal distribution in a hydrophilic-lipophilic balance of 14 with particle diameters of 115.56 ± 1.68 nn and zeta potential of −29.63 ± 3.46 mV. The nanoemulsion showed larvicidal action with LC50 = 2.91 µg∙mL−1 and residual larvicidal effect for 72 h after application to A. aegypti larvae. Consequently, the nanobiotechnological product derived from the essential oil of P. heptaphyllum resin could be used against infectious disease vectors. 相似文献
124.
Renata leite Tavares Maria Helena Araújo de Vasconcelos Maria Letícia da Veiga Dutra Aline Barbosa DOliveira Marcos dos Santos Lima Mirian Graciela da Silva Stiebbe Salvadori Ramon de Alencar Pereira Adriano Francisco Alves Yuri Mangueira do Nascimento Josean Fechine Tavares Omar Guzman-Quevedo Jailane de Souza Aquino 《Molecules (Basel, Switzerland)》2020,25(23)
This study evaluated the effect of Mucuna pruriens (MP) administration on neuroinflammation and behavioral and murinometric parameters in obese rats. Proximate composition, oligosaccharide and phenolic compound profile of MP were determined. Wistar adult male rats were randomized into healthy (HG) and obese group (OG). The HG consumed a control chow diet while OG consumed a cafeteria diet for eight weeks. Then, they were subdivided into: Healthy (HG); Healthy with MP administration (HGMP); Obese (OG); Obese with MP administration (OGMP), with the consumption of the respective diets remaining for another eight weeks, in addition to gavage with MP extract to supplemented groups (750 mg/kg weight). MP presented a composition rich in proteins and phenolic compounds, especially catechin, in addition to 1-kestose and levodopa. Supplementation reduced food intake, body weight, and thoracic and abdominal circumferences in obese rats. MP showed anxiolytic and antidepressant effects and reduced morphological damage and expression of interleukin 6 in the hippocampus of obese rats. MP treatment showed satietogenic, slimming, anxiolytic and antidepressant effects, besides to minimizing hippocampal neuroinflammation in obese rats. Our results demonstrated the potential anti-obesity of MP which are probably related to the high content of bioactive compounds present in this plant extract. 相似文献
125.
Murilo P. Santos Maria G. F. Torraga Natlia B. Barbosa Denise T. Tavares Reinaldo Giudici 《大分子反应工程》2020,14(3)
The styrene and vinyl neodecanoate copolymerization system shows a strong tendency to form two separate homopolymers. In order to improve the feeding strategies and hence the copolymer uniformity, it is necessary to know the reactivity ratios between these monomers. The error‐in‐variables‐method (EVM) is the most recommended mathematical procedure for estimating these parameters. Experiments on free‐radical copolymerization in solution in sealed ampoules are carried out to provide data for the conversion (via gravimetry) and fractional monomer compositions (via Fourier transform mid‐infrared (mid‐FT‐IR) spectroscopy). These data allow estimation of the reactivity ratios. EVM appropriately takes into account the experimental errors in the data and allows determination of the reactivity ratio values by the Mayo–Lewis model (r1 = 28.60 and r2 = 1.23). The convergence and robustness of the method decrease considerably with a larger discrepancy between the reactivity values. 相似文献
126.
Gisele A. B. Canuto Emerson A. Castilho-Martins Marina F. M. Tavares Luis Rivas Coral Barbas Ángeles López-Gonzálvez 《Analytical and bioanalytical chemistry》2014,406(14):3459-3476
Miltefosine (MT) (hexadecylphosphocholine) was implemented to cope with resistance against antimonials, the classical treatment in Leishmaniasis. Given the scarcity of anti- Leishmania (L) drugs and the increasing appearance of resistance, there is an obvious need for understanding the mechanism of action and development of such resistance. Metabolomics is an increasingly popular tool in the life sciences due to it being a relatively fast and accurate technique that can be applied either with a particular focus or in a global manner to reveal new knowledge about biological systems. Three analytical platforms, gas chromatography (GC), liquid chromatography (LC) and capillary electrophoresis (CE) have been coupled to mass spectrometry (MS) to obtain a broad picture of metabolic changes in the parasite. Impairment of the polyamine metabolism from arginine (Arg) to trypanothione in susceptible parasites treated with MT was in some way expected, considering the reactive oxygen species (ROS) production described for MT. Importantly, in resistant parasites an increase in the levels of amino acids was the most outstanding feature, probably related to the adaptation of the resistant strain for its survival inside the parasitophorous vacuole. Online Abstract Figure
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127.
Luana B. S. Nascimento Marcos V. Leal‐Costa Marcela A. S. Coutinho Nattacha dos S. Moreira Celso L. S. Lage Nancy dos S. Barbi Sônia S. Costa Eliana S. Tavares 《Photochemistry and photobiology》2013,89(2):391-399
Antioxidant compounds protect plants against oxidative stress caused by environmental conditions. Different light qualities, such as UV‐A radiation and blue light, have shown positive effects on the production of phenols in plants. Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) is used for treating wounds and inflammations. Some of these beneficial effects are attributed to the antioxidant activity of plant components. We investigated the effects of blue light and UV‐A radiation supplementation on the total phenol content, antioxidant activity and chromatographic profile of aqueous extracts from leaves of K. pinnata. Monoclonal plants were grown under white light, white plus blue light and white plus UV‐A radiation. Supplemental blue light improved the antioxidant activity and changed the phenolic profile of the extracts. Analysis by HPLC of supplemental blue‐light plant extracts revealed a higher proportion of the major flavonoid quercetin 3‐O‐α‐l ‐arabinopyranosyl (1→2) α‐l ‐rhamnopyranoside, as well as the presence of a wide variety of other phenolic substances. These findings may explain the higher antioxidant activity observed for this extract. Blue light is proposed as a supplemental light source in the cultivation of K. pinnata, to improve its antioxidant activity. 相似文献
128.
Fábio de Souza Dias Aline Klassen Marina Franco Maggi Tavares Jorge Maurício David 《Chromatographia》2013,76(9-10):559-563
Six phenolic compounds were separated and determined by capillary zone electrophoresis in red wine from Brazil’s region Vale do São Francisco with total analysis time of 12 min. The limit of detections varied from 1.59 to 2.24 mg L?1. The relative standard deviations (for n = 6) varied from 0.28 to 3.50 %. The red wine samples analyzed were bought in the local market and the phenolic compound recoveries were in the range of 98–101 %. The concentrations of gallic acid in the samples of wines varied from 16.0 to 42.0 mg L?1, caffeic acid (3.16–5.18 mg L?1), syringic acid (5.73–13.0 mg L?1), kaempferol (2.32–4.33 mg L?1), quercetin (1.68–4.03 mg L?1), myricetin (7.52–25.1 mg L?1). The concentrations found agree with data reported in the literature. 相似文献
129.
Paula F. dos Santos Marcelo C. Duarte Denise Aline C. Bezerra Maria de F. Agra José M. Barbosa Filho Marcelo S. da Silva Josean F. Tavares 《Helvetica chimica acta》2013,96(6):1085-1092
The phytochemical investigation of Xylopia langsdorffiana A.St.‐Hil. & Tul . led to the isolation of eight diterpenes, i.e., of the four new compounds (5β,7β,8α,9β,10α,12α)‐atisane‐7,16‐diol 7‐acetate ( 1 ), named xylodiol 7‐acetate, (5β,8α,9β,10α,12α)‐16‐hydroxyatisan‐7‐one ( 2 ), named xylopinone, (3α,12Z)‐3‐hydroxy‐ent‐labda‐8(20),12,14‐trien‐18‐oic acid ( 3 ), named labdorffianic acid A, and 8,20‐epoxy‐13‐hydroxy‐ent‐labd‐14‐en‐18‐oic acid ( 4 ), named labdorffianic acid B, and of the four known compounds 5 – 8 , i.e., ent‐kauran‐16‐ol, ent‐kaur‐16‐en‐19‐oic acid, ent‐kaur‐16‐en‐19‐ol, and ent‐trachyloban‐18‐oic acid. The structures were established by IR, HR‐ESI‐MS, and NMR data analysis with the aid of 2D techniques. 相似文献
130.
A. Dias Tavares Jr. C. E. Fellows C. A. Massone 《Applied physics. B, Lasers and optics》1985,38(4):259-262
An analysis of a modified electrode geometry for pulsed gas-laser excitation circuits, generating shorter excitation pulses than those normally obtained, is reported. Results from an atmospheric N2 laser obtained with this electrode geometry are compared with others available in the literature.Paper partially presented at the XIII Intern. Quantum Electronics Conf., Los Angeles, CA, USA (1984) 相似文献