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61.
Stella M. Zabala R.M. Torres Sanchez 《Journal of Dispersion Science and Technology》2013,34(7):957-968
The movement of water originated by the spreading of two surfactants was analyzed in glass beads as well as on soil systems, both of particles of nonuniform size The higher difference of surface tension produced in the system by 1 -hexadecanol compared to that of 1-tetradecanol led therefore to a higher amount of water moved. Decreased proportion of the smaller sized particles in glass beads system produced a decrease in the total water moved by both surfactants. Organic matter acted in soil as a second surfactant in glass beads. This effect was compared in glass beads systems once 1-hexadecanol was evenly distributed among the particles as continuous film, which played a role alike that of organic matter in soil and then a second surfactant 1-tetradecanol was added. These additional surfactant effect diminished the difference between initial and final surface tension (surface tension depression) of the system and so the total water moved. The soil organic matter (1.7%) modified the water movement curve in the presence of low (0.2g) content of 1-hexadecanol, whereas for high content of either alcohol (0.4g) or low content of 1-tetradecanol content (0.2g) the water movement curves were the same 相似文献
62.
In this note, we describe a procedure to construct generalized complex structures whose type change locus has arbitrarily many path components on products of the circle with a connected sum of closed 3-manifolds. As an application, we use the procedure to exhibit such geometric structures on a myriad of simply connected 4-manifolds among many others. 相似文献
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Pedro Marcos Frugeri Camila Marchioni Ayla Campos do Lago Célio Wisniewski 《Analytical letters》2018,51(10):1492-1504
This work proposes a flow injection analysis system for sulfaguanidine determination in pharmaceutical and food samples. The method was based on the reaction of sulfaguanidine with nitronium ion to produce a colored complex whose absorbance was measured at 545?nm. The flow injection analysis system’s significant parameters were checked by a fractional factorial design 27–2 and optimization by a Doehlert matrix. The flow injection analysis system shows optimum values at 0.28, 2.00, and 0.11% (w/v) for N-naphtil ethylenediamine, ammonium sulfamate, and sodium nitrite concentrations, respectively. The possible interferents present in pharmaceutical and food samples were assessed by a multivariate technique and depicted on probability charts, indicating no significant interferences at the 95% level of confidence interval. The method showed detection and quantification limits of 0.012 and 0.039?mg?L?1, an analytical frequency of 30 readings h?1 and precision always lower than 5.0% expressed as the relative standard deviation. The obtained results were in accordance with those obtained by high-performance liquid chromatography. 相似文献
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de Oliveira Cristina Soltovski Bet Camila Delinski Bisinella Radla Zabian Bassetto Waiga Lucas Henrique Colman Tiago André Denck Schnitzler Egon 《Journal of Thermal Analysis and Calorimetry》2018,133(3):1491-1498
Journal of Thermal Analysis and Calorimetry - Samples of potato starch (PS), sweet potato starch (SPS) and their binary mixtures, with moisture levels of 10, 15 and 20% (db), were submitted to... 相似文献
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A simple and high‐resolution HPLC‐PDA method for simultaneous quantification of local anesthetics in in vitro buccal permeation enhancement studies
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Renê O. Couto Camila Cubayachi Renata F. V. Lopez Cristiane M. de Gaitani Vinícius Pedrazzi Osvaldo de Freitas 《Biomedical chromatography : BMC》2016,30(6):857-866
A simple, isocratic, high‐resolution and prompt HPLC‐PDA method was developed and validated for the simultaneous quantification of prilocaine (PCL) and lidocaine (LCL) hydrochlorides in in vitro buccal iontophoresis‐driven permeation studies. A reversed‐phase C18 column (250 mm x 4.6 mm, 3μm, 110Å) was used for the chromatographic separation. The mobile phase contained acetonitrile: 0.1M sodium phosphate buffer, pH 7.0 (1:1, v/v), plus 0.05% (v/v) diethylamine. The isocratic flow rate was set at 1 mL/min and the detection wavelength was 203 nm. PCL and LCL eluted in 8.9 min and 13 min, respectively, and the system suitability parameters varied within an acceptable range. The method was selective, sensitive, precise, accurate and robust, producing a linear plot at the concentration range of 0.25 to 10 µg/mL. The application of this method was demonstrated by a significant enhancement of the permeation of PCL and LCL with the application of iontophoresis (1 mA/cm2 per 1 h) through isolated porcine esophageal epithelium. The amount of the drug retained in the epithelium also increased with the application of an electrical current. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Jadriane A. Xavier Thaissa L. Silva Eduardo Caio Torres-Santos Camila Calado de Vasconcelos Anastacio Boane Ricardo Alexandre dos Santos Andre Felippe A. Xavier Marília O.F. Goulart 《Current Opinion in Electrochemistry》2021
This review discusses the state of the art, challenges, and perspectives in recent applications of nitroaromatics and nitroheteroaromatics, which are redox-bio-activated drugs or leads, in Medicinal Chemistry. It deals mainly with the electrochemical approach toward the electron transfer-based molecular mechanisms of drug action, drug design, estimation and measurement of redox potentials, correlation of physicochemical and pharmacological data, and electrochemical studies of the main representatives of nitro-containing prodrugs, along with approaches to combat their toxicity issues, aiming at a better therapeutic profile. Electrochemical investigation plays essential roles, being strategic in the design and discovery of potential medicines. 相似文献