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101.
Vesicles are of great interest as drug delivery system or models for cell membranes. For many applications, it is necessary
to produce vesicles which are unilamellar, monodisperse, easy to adjust in size, and which can be filled with various types
of active compounds. In a series of experiments, we produced giant vesicles with dimension of several millimeters by phase
transfer processes. This new technique allowed synthesizing defined vesicles with lipid and surfactant membranes. The preparation
of these aggregates occurred in two steps. First, we filled some amount of water into a cuvette and covered this liquid with
an oil phase. Surfactants or lipids were solved either in the water or the oil phase. In the second step, a water droplet
filled with methyl blue and saccharose was formed with a syringe in the oil phase. Due to density difference, the water droplet
passed the plane oil/water interface and during this process it was transformed into a vesicle. The giant liposomes, thus
formed, showed a high sensitivity against variations of the osmotic pressure, and their stability reached from seconds to
hours. Due to the phase transfer process, the vesicle membranes often contained incorporated lenses of oil. If this hydrophobic
liquid was released from the membrane, the vesicles decayed into smaller liposomes with a broad particle size distribution. 相似文献
102.
Maria Andreea Nistor Simona Gabriela Muntean Bianca Maranescu Aurelia Visa 《应用有机金属化学》2020,34(11):e5939
A very intense study class of complex porous materials, metal–organic frameworks (MOFs), composed of diverse central metallic ions attached to organic linkers, was used in this study as adsorbant materials from wastewaters. Phosphonate MOFs were prepared by the reaction of divalent inorganic salts (CoSO4 · 7H2O, NiSO4 · 6H2O, CuSO4 · 5H2O,) with vinyl phosphonic acid in hydrothermal conditions, obtaining cobalt, nickel, and copper vinylphosphonate (CoVP, NiVP, and CuVP). During synthesis the experimental conditions were varied in terms of time, temperature, and pH. The synthesized materials were characterized by Fourier transform infrared, thermogravimetric analysis, scanning electron microscopy, and X-ray crystallography. The efficiency of MOFs as adsorbents was investigated for diverse initial dye concentrations at different pH values and at three temperatures (25, 40, and 55°C). The synthesized materials presented good efficiency in the elimination of anionic as well as cationic type of dyes from aqueous solutions. The highest adsorption capacities were obtained working at optimum solution pH 4.2 for Acid Orange 7 and 10 for Basic Fuchsine, using 1 g/L of MOFs at room temperature (25°C). The adsorption capacities increase in the following order: CuVP < NiVP < CoVP. 相似文献
103.
104.
105.
Aurelia Magdalena Dianu Marius Iordache 《International journal of environmental analytical chemistry》2016,96(4):373-386
Uranium concentration levels in surface waters are of great importance because uranium presents both chemical and radiological hazard to the environment. The subject of this article is to establish that spectrophotometric method for uranium evaluation in effluents collected from liquid waste treatment generated during fabrication of nuclear fuel elements could be replaced by the optical fluorimetric technique. Both methods are briefly described. The comparison of the two methods was carried out with regard to international standards and national regulations offering from a statistical point of view a useful approach to compare two analytical measurement techniques. This methodology can be applied to any other measurement procedures. A discussion about the compliance of the fluorimetric analytical method with the mandatory discharge level of uranium concentration in surface waters is also presented. 相似文献
106.
Aurelia Tar Mihail Barboiu Yves-Marie Legrand Constantin Luca 《Journal of inclusion phenomena and macrocyclic chemistry》2008,60(1-2):35-41
The stability of complexes formed by a series of Schiff-base lariat ethers, derived from 4,13-diaza-18-crown-6, 1 with Ag+, Pb2+, Cu2+ cations, has been comparatively determined, in methanol: dichloromethane solution. We present here the synthesis and an interesting
competitive potentiometry method useful for the stability constant determination for a new family of Schiff-base bibracchial
lariat ethers. The stability constants and the selectivity in competitive complexation of Ag+, Pb2+ and Cu2+ cations by macrocyclic receptors 1–7 (L), can be accurately evaluated and species distribution diagrams can be calculated for individual system. In all cases
further functionalization of bibracchial lariat ethers 2–7 is accompanied by an increasing of the selectivity, relative to the complexes of the initial 4,13-diaza-18-crown-6 macrocycle
1. 相似文献
107.
Racles Carmen Airinei Anton Stoica Iuliana Ioanid Aurelia 《Journal of nanoparticle research》2010,12(6):2163-2177
Journal of Nanoparticle Research - Silver nanoparticles were obtained in aqueous medium, at room temperature, by redox reactions, with or without glucose, in the presence of a glucose-containing... 相似文献
108.
Mălina Răileanu Maria Giubelan Maria Zaharescu Andrei Jitianu Ion Peleanu Aurelia Meghea 《Journal of Sol-Gel Science and Technology》2004,31(1-3):51-58
Since their discovery, fullerenes in general and buckminsterfullerene C60 in particular, became a subject of great interest for studies. Being compatible with the sol–gel process, one of the promising approaches is to incorporate the fullerene molecules in sol–gel oxide matrices. Great part of studies deals with SiO2 sol–gel oxide as the optimal matrix for entrapment of organic molecules. C60-doped silica matrices used through our present study have been prepared by sol–gel processing, using different alkoxide precursors, as a silicon oxide source: tetraethoxysilane (a), methyltriethoxysilane (b), phenyltriethoxysilane (c) and a mixture of phenyltriethoxysilane and tetraethoxysilane (d). C60-to-Si molar ratio was chosen to be 1.0 × 10?3:1 for all materials synthesized, final oxide composition remaining unchanged in all cases. The effect of ultrasounds on the gelation process was established by preparing two series of samples, either via sonication or in the absence of ultrasound processing. The properties of the resulted materials were also established. The prepared samples were characterized by XRD, IR, RPE and UV-VIS spectrometry. All methods have put in evidence the embedment of the fullerene into the silica matrix. 相似文献
109.
Aurelia Cionga Viorica Florescu 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1986,2(1):49-59
We consider Rayleigh scattering from a hydrogenlike atom in an arbitrary excitedn=2 state, and we investigate theoretically the dependence of the scattered radiation intensity and Stokes parameters on the state multipoles for the case of unpolarized incident radiation. Because in then=2 case Rayleigh scattering can not be accompanied by the change of the electron angular momentum, only 10 out of the 16 state multipoles influence the scattered radiation attributes. Our study reveals the existence of a measurable quantity which is determined only by Rayleigh scattering from 2p states. For the particular case of excitation by electron impact, some quantitative predictions are made, at the photon scattering angle ?=π/2, based on values for the state multipoles extracted from the literature (Blum and Kleinpoppen, Band). The vicinity of Balmer α and Lyman α resonances are studied in detail. 相似文献
110.
New reactions of (vinylimino)phosphoranes with aldehydes involving an initial nucleophilic attack of the beta-carbon atom of the vinyl side chain on the carbonyl carbon atom are reported. Iminophosphorane 4 derived from ethyl beta-azidoacrylate reacts with substituted cinnamyl aldehydes to give a mixture of 2-arylpyridine and 4-styryldihydropyridine derivatives, whereas the reaction with substituted benzaldehydes provides 4-aryldihydropyridine derivatives. However, the iminophosphorane 16 derived from the diethyl azidofumarate reacts with cinnamyl aldehydes through the expected aza-Wittig fashion to give 4-arylpyridine derivatives after dehydrogenation of the resulting dihydropyridine. 相似文献