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排序方式: 共有127条查询结果,搜索用时 15 毫秒
1.
Zuo YY Gitiafroz R Acosta E Policova Z Cox PN Hair ML Neumann AW 《Langmuir : the ACS journal of surfaces and colloids》2005,21(23):10593-10601
The in vitro adsorption kinetics of lung surfactant at air-water interfaces is affected by both the composition of the surfactant preparations and the conditions under which the assessment is conducted. Relevant experimental conditions are surfactant concentration, temperature, subphase pH, electrolyte concentration, humidity, and gas composition of the atmosphere exposed to the interface. The effect of humidity on the adsorption kinetics of a therapeutic lung surfactant preparation, bovine lipid extract surfactant (BLES), was studied by measuring the dynamic surface tension (DST). Axisymmetric drop shape analysis (ADSA) was used in conjunction with three different experimental methodologies, i.e., captive bubble (CB), pendant drop (PD), and constrained sessile drop (CSD), to measure the DST. The experimental results obtained from these three methodologies show that for 100% relative humidity (RH) at 37 degrees C the rate of adsorption of BLES at an air-water interface is substantially slower than for low humidity. It is also found that there is a difference in the rate of surface tension decrease measured from the PD and CB/CSD methods. These experimental results agree well with an adsorption model that considers the combined effects of entropic force, electrostatic interaction, and gravity. These findings have implications for the development and evaluation of new formulations for surfactant replacement therapy. 相似文献
2.
Stationary phase containing quinolin-8-ol immobilized on macroporous methacrylate support for the affinity chromatography of porcine pepsin A is described. Optimized chromatographic conditions for separation of porcine pepsin A on this stationary phase were found investigating the influence of pH, concentration, ionic strength and chemical composition of the used mobile phases. The stationary phase shows a good reproducibility of chromatographic analyses (relative standard deviation, +/-2%), a high recovery (ca. 93%) and a satisfactory capacity (13 mg pepsin A/1 mL stationary phase) for porcine pepsin A. The obtained findings confirm the applicability of affinity chromatography on the stationary phase with immobilized quinolin-8-ol to the isolation and determination of porcine pepsin A. 相似文献
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Advanced Sensing of Antibiotics with Magnetic Gold Nanocomposite: Electrochemical Detection of Chloramphenicol
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Dr. Petr Jakubec Dr. Veronika Urbanová Dr. Zdenka Medříková Prof. Dr. Radek Zbořil 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14279-14284
The sensing and accurate determination of antibiotics in various environments represents a big challenge, mainly owing to their widespread use in medicine, veterinary practice, and other fields. Therefore, a new, simple electrochemical sensor for the detection of antibiotic chloramphenicol (CAP) has been developed in this work. The amplification strategy of the sensor is based on the application of magnetite nanostructures stabilized with carboxymethyl cellulose (Fe3O4‐CMC) and decorated with nanometer‐sized Au nanoparticles (NPs) (Fe3O4‐CMC@Au). In this case, CMC serves as a stabilizing agent, preventing the aggregation of Fe3O4 NPs, and hence, enabling the kinetic barrier for electron transport to be overcome, and the Au NPs serve as an electron‐conducting tunnel for better electron transport. As a proof of concept, the developed nanosensor is used for the detection of CAP in human urine samples, giving a recovery value of around 97 %, which indicates the high accuracy of the as‐prepared nanosensor. 相似文献
5.
Kokol Vanja Vivod Vera Peršin Zdenka Čolić Miodrag Kolar Matjaž 《Cellulose (London, England)》2021,28(10):6545-6565
Cellulose - Bio-based, renewable and biodegradable products with multifunctional properties are also becoming basic trends in the textile sector. In this frame, cellulose nanofibrils (CNFs) have... 相似文献
6.
Antonio Di Martino Pavel Kucharczyk Zdenka Capakova Petr Humpolicek Vladimir Sedlarik 《Journal of nanoparticle research》2017,19(2):71
In the presented work, amphiphilic nanoparticles based on chitosan and carboxy-enriched polylactic acid have been prepared to improve the stability of the pro-drug temozolomide in physiological media by encapsulation. The carrier, with a diameter in the range of 150–180 nm, was able to accommodate up to 800 μg of temozolomide per mg of polymer. The obtained formulation showed good stability in physiological condition and preparation media up to 1 month. Temozolomide loaded inside the carrier exhibited greater stability than the free drug, in particular in simulated physiological solution at pH 7.4 where the hydrolysis in the inactive metabolite was clearly delayed. CS-SPLA nanoparticles demonstrated a pH-dependent TMZ release kinetics with the opportunity to increase or decrease the rate. Mass spectroscopy, UV-Vis analysis, and in vitro cell tests confirmed the improvement in temozolomide stability and effectiveness when loaded into the polymeric carrier, in comparison with the free drug. 相似文献
7.
Tishchenko G Dybal J Mészárosová K Sedláková Z Bleha M 《Journal of chromatography. A》2002,954(1-2):115-126
Ni2+ complexes of the chelating nonporous and porous bead sorbents based on methacrylic esters crosslinked with ethylene dimethacrylate were used in isolation of the horseradish peroxidase-specific immunoglobulin IgG1 from the crude mouse ascitic fluid by immobilized metal ion affinity chromatography (IMAC). Iminodiacetic and aspartic acids were attached to porous poly(glycidyl methacrylate) beads differing in size, morphology and chemical composition. Ethylenediaminetriacetic acid and quinolin-8-ol chelating groups were attached mainly to the surface hydroxyl groups in nonporous poly(diethylene glycol methacrylate) beads through spacers. The latter sorbents exhibited better kinetic characteristics than the former but a very low IgG1 sorption capacity. In a single-step IMAC procedure, the best efficiency in the specific IgG1 purification was obtained with porous sorbents (recovery 92%, purity 73%). Differences in IMAC separations are discussed from the point of view of morphology of polymer beads as well as of the type and concentration of chelating ligands. 相似文献
8.
Lenka Novotna Tereza Emmerova Daniel Horak Zdenka Kucerova Marie Ticha 《Journal of chromatography. A》2010,1217(51):8032-8040
Magnetic non-porous hydrophilic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) microspheres prepared by the dispersion polymerization and modified with iminodiacetic acid (IDA) were employed for the IMAC separation of phosphopeptides. Fe3+ and Ga3+ ions immobilized on IDA-modified magnetic microspheres were used for the enrichment of phosphopeptides from the proteolytic digests of two model proteins differing in their physico-chemical properties and phosphate group content: porcine pepsin A and bovine α-casein. The optimum conditions for phosphopeptide adsorption and desorption in both cases were investigated and compared. The phosphopeptides separated from the proteolytic digests were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The ability of the prepared Fe3+- and Ga3+-IDA-modified magnetic microspheres to capture phosphopeptides from complex mixtures was shown on an example of bovine milk proteolytic digest. 相似文献
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States on sharply dominating effect algebras 总被引:1,自引:0,他引:1
Zdenka RIEANOV~ WU JunDe~ 《中国科学A辑(英文版)》2008,51(5):907-914
We prove that sharply dominating Archimedean atomic lattice effect algebras can be characterized by the property called basic decomposition of elements.As an application we prove the state smearing theorem for these effect algebras. 相似文献