Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
1.
Materials (Basel) ; 15(16)2022 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-36013711

RESUMEN

Oxidized mesoporous carbon CSBA-15, obtained by the hard method, was applied to remove rhodamine B from the aqueous system. The process of carbon oxidation was performed using 0.5 and 5 M of nitric (V) acid solution at 70 and 100 °C. Functionalization of mesoporous carbon with HNO3 solutions led to reduction in the surface area, pore volume, and micropore area, however, it also led to an increased number of oxygen functional groups of acidic character. The functional groups probably are located at the entrance of micropores, in this way, reducing the values of textural parameters. Isotherms of rhodamine B adsorption indicate that the oxidation of mesoporous carbons resulted in an increase in the effectiveness of the removal of this dye from aqueous solutions. The influence of temperature, pH, and contact time of mesoporous material/rhodamine B on the effectiveness of dye removal was tested. The process of dye adsorption on the surfaces of the materials studied was established to be most effective at pH 12 and at 60 °C. Kinetic studies of the process of adsorption proved that the equilibrium state between the dye molecules and mesoporous carbon materials is reached after about 1 h. The adsorption kinetics were well fitted using a pseudo-second-order model. The most effective in rhodamine B removal was the sample CSBA-15-5-100, containing the greatest number of oxygen functional groups of acidic character. The Langmuir model best represented equilibrium data.

2.
Percept Mot Skills ; 125(3): 612-625, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29764332

RESUMEN

This study sought to determine differences in fencers' visual perceptions during duels (preparatory actions) with right- versus left-handed opponents. Participants were 12 top-ranking right-handed female foil fencers (aged 16-30 years, M = 20.86, SD = 4.76) taking part in a training camp. Testing employed SensoMotoric Instruments Eye Tracking Glasses (SMI ETG 2.0) with eye-tracking analyses covering the visual attention time devoted to various areas of the opposing fencer's body (areas of interest), average fixation, number of glances, and number of fixations during preparatory actions in duels. Each test was conducted during preparatory actions in 20-second staged duels, first against a right-handed, and then against a left-handed opponent. Against left-handed (vs. right-handed) opponents, fencers spent significantly more time looking at and significantly more often fixated on the armed hand. When fighting against right-handed (vs. left-handed) opponents, fencers devoted more time and fixated more often on the opponent's upper torso. These results may point to an interesting phenomenon in which left-handed fencers benefit from weaker strategies adopted by their right-handed opponents who may fixate on the forearm and arm of the weapon hand.


Asunto(s)
Atención/fisiología , Fijación Ocular/fisiología , Lateralidad Funcional/fisiología , Deportes/fisiología , Percepción Visual/fisiología , Adolescente , Adulto , Femenino , Humanos , Adulto Joven
3.
Sci Total Environ ; 627: 438-449, 2018 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-29426166

RESUMEN

In the years 2014-2016 biomonitoring studies were conducted in the forest areas of south and north-eastern Poland: the Karkonosze Mountains, the Beskidy Mountains, the Borecka Forest, the Knyszynska Forest and the Bialowieska Forest. This study used epigeic moss Pleurozium schreberi and epiphytic lichens Hypogymnia physodes. Samples were collected in spring, summer and autumn. Approximately 500 samples of moss and lichens were collected for the study. In the samples, Mn, Ni, Cu, Zn, Cd, Hg and Pb concentrations were determined. Based on the obtained results, the studied areas were ranked by extent of heavy-metal deposition: Beskidy > Karkonosze Mountains > forests of north-eastern Poland. Some seasonal changes in concentrations of metals accumulated in moss and lichens were also indicated. There was observed, i.a., an increase in Cd concentration at the beginning of the growing season, which may be related to low emissions during the heating season. Analysis of the surface distribution of deposition of metals in the studied areas showed a significant contribution of nearby territorial emissions and unidentified local emission sources. The contribution of distant emission to Zn, Hg and Pb deposition levels in the Karkonosze and Beskidy region was also indicated.


Asunto(s)
Contaminantes Atmosféricos/análisis , Briófitas/química , Monitoreo del Ambiente/métodos , Líquenes/química , Metales Pesados/análisis , Bosques , Polonia
4.
Eur J Pharm Biopharm ; 94: 550-8, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26170160

RESUMEN

The ordered mesoporous silicas SBA-15 and KIT-6, modified with lanthanum, have been for the first time applied in investigation of ibuprofen adsorption and release. The materials of hexagonal and regular structure were obtained by the hydrothermal method using a triblock copolymer Pluronic P123 as a template. The mesoporous silicas were impregnated with an aqueous solution of lanthanum(III) chloride in the amount necessary to obtain 1, 3 and 5wt.% La loading. The physicochemical properties of the modified silicas were characterised by X-ray diffraction, transmission electron microscopy, UV-Vis spectrophotometry and low-temperature nitrogen sorption. The results showed that lanthanum strongly determined structural as well as textural properties of the silicas. The samples of modified silica were checked for the ability to adsorb and release of ibuprofen. The storage capacity of the modified silicas obtained increased with increasing their average pore diameter and percentage content of lanthanum. The amount of ibuprofen adsorbed onto KIT-6 silica modified with La was higher than that adsorbed onto SBA-15 materials. The high coverage of lanthanum on the surface of KIT-6 and SBA-15 solids was found to increase the amount of ibuprofen and the rate of its release.


Asunto(s)
Antiinflamatorios no Esteroideos/administración & dosificación , Portadores de Fármacos/química , Ibuprofeno/administración & dosificación , Lantano/química , Dióxido de Silicio/química , Adsorción , Antiinflamatorios no Esteroideos/química , Composición de Medicamentos , Liberación de Fármacos , Ibuprofeno/química , Microscopía Electrónica de Transmisión , Tamaño de la Partícula , Porosidad , Difracción de Polvo , Espectrofotometría Ultravioleta , Propiedades de Superficie , Difracción de Rayos X
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA