scholarly journals From Static to Dynamic Modeling of Surfactants Micellization

2021 ◽  
Vol 58 (1) ◽  
pp. 4-12
Author(s):  
Zuzana Vitková ◽  
Marián Tárník ◽  
Jarmila Pavlovičová ◽  
Anton Vitko ◽  
Jarmila Oremusová ◽  
...  
Keyword(s):  
Concentration Dependence ◽  
Order Differential Equation ◽  
Water Solution ◽  
Surfactant Solution ◽  
Drug Carriers ◽  
Simplex Algorithm ◽  
Model Parameters ◽  
Downhill Simplex ◽  
Physical Quantities

Abstract Micelles and micellization appeal long lasting interest as promising drug carriers. A conventional parameter providing information about formation of micelles is critical micelle concentration (cmc). Its value roughly separates two states of the surfactant solution – namely states with and without presence of micelles. If concentration of surfactants in water solution approaches cmc some physical quantities abruptly change, and this phenomenon is a key to determine value of the cmc. From numerous approaches for determination of the cmc the paper considers the conductivity-based method. But rather than studying the mechanism of micellization that is primarily carried out by the colloid chemists, the paper is focused on the development of an information rich and optimal dynamical model of the conductivity vs. concentration dependence. The model is derived from the solutions of the 1st order differential equation. The optimal model parameters are determined by the downhill simplex algorithm and the cmc is computed on the basis of the curvature of the concentration dependence of the conductivity.

Methods for the Determination of the Purity of Exosomes

2020 ◽  
Vol 25 (42) ◽  
pp. 4464-4485 ◽  
Author(s):  
Katarzyna Kluszczyńska ◽  
Liliana Czernek ◽  
Wojciech Cypryk ◽  
Łukasz Pęczek ◽  
Markus Düchler
Keyword(s):  
Drug Transport ◽  
Biological Fluids ◽  
Drug Carriers ◽  
Biological Functions ◽  
Isolation And Purification ◽  
Pubmed Database ◽  
High Concentrations ◽  
Targeted Release

Background: Exosomes open exciting new opportunities for advanced drug transport and targeted release. Furthermore, exosomes may be used for vaccination, immunosuppression or wound healing. To fully utilize their potential as drug carriers or immune-modulatory agents, the optimal purity of exosome preparations is of crucial importance. Methods: Articles describing the isolation and purification of exosomes were retrieved from the PubMed database. Results: Exosomes are often separated from biological fluids containing high concentrations of proteins, lipids and other molecules that keep vesicle purification challenging. A great number of purification protocols have been published, however, their outcome is difficult to compare because the assessment of purity has not been standardized. In this review, we first give an overview of the generation and composition of exosomes, as well as their multifaceted biological functions that stimulated various medical applications. Finally, we describe various methods that have been used to purify small vesicles and to assess the purity of exosome preparations and critically compare the quality of these evaluation protocols. Conclusion: Combinations of various techniques have to be applied to reach the required purity and quality control of exosome preparations.

Controlled Growth and Characterization Ag/ZnO Nanotetrapods for Humidity Sensing

2018 ◽  
Vol 21 (7) ◽  
pp. 462-467
Author(s):  
Babak Sadeghi
Keyword(s):  
Room Temperature ◽  
Zinc Complex ◽  
Water Solution ◽  
Particle Morphology ◽  
Quick Response ◽  
Separation System ◽  
Humidity Sensing ◽  
Sensor Material ◽  
Highly Sensitive

Aim and Objective: Ultrafine Ag/ZnO nanotetrapods (AZNTP) have been prepared successfully using silver (I)–bis (oxalato) zinc complex and 1, 3-diaminopropane (DAP) with a phase separation system, and have been injected into a diethyl/water solution. Materials and Methods: This crystal structure and lattice constant of the AZNTP obtained were investigated by means of a SEM, XRD, TEM and UV-vis spectrum. Results: The results of the present study demonstrated the growth and characterization AZNTP for humidity sensing and DAP plays a key role in the determination of particle morphology. AZNTP films with 23 nm in arm diameter have shown highly sensitive, quick response sensor material that works at room temperature.

Experience with the IMMa tyre test bench for the determination of tyre model parameters using genetic techniques

2005 ◽  
Vol 43 (sup1) ◽  
pp. 253-266 ◽  
Author(s):  
J. A. Cabrera ◽  
A. Ortiz ◽  
E. Carabias ◽  
A. Simón
Keyword(s):  
Test Bench ◽  
Model Parameters ◽  
Tyre Model ◽  
Genetic Techniques

Direct determination of the concentration dependence of diffusivities using combined model-based Raman and NMR experiments

2009 ◽  
Vol 277 (2) ◽  
pp. 96-106 ◽  
Author(s):  
E. Kriesten ◽  
M.A. Voda ◽  
A. Bardow ◽  
V. Göke ◽  
F. Casanova ◽  
...  
Keyword(s):  
Concentration Dependence ◽  
Direct Determination ◽  
Combined Model ◽  
Model Based

scholarly journals A Comparative Study of Advanced Stationary Phases for Fast Liquid Chromatography Separation of Synthetic Food Colorants

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3335
Author(s):  
Ivona Lhotská ◽  
Petr Solich ◽  
Dalibor Šatínský
Keyword(s):  
Separation Efficiency ◽  
Water Solution ◽  
Stationary Phases ◽  
Gradient Elution ◽  
Synthetic Food Colorants ◽  
Liquid Chromatography Separation ◽  
Method Optimization ◽  
Superficially Porous Particles ◽  
Fast Liquid Chromatography

Food analysis demands fast methods for routine control and high throughput of samples. Chromatographic separation enables simultaneous determination of numerous compounds in complex matrices, several approaches increasing separation efficiency and speed of analysis were involved. In this work, modern types of column with monolithic rod or superficially porous particles were employed and compared for determination of eight synthetic food dyes, their chromatographic performance was evaluated. During method optimization, cyano stationary phase Chromolith Performance CN 100 × 4.6 mm and Ascentis Express ES-CN 100 × 4.6 mm, 5 µm were selected for the separation of polar colorants. The separation was performed by gradient elution of acetonitrile/methanol and 2% water solution of ammonium acetate at flow rate 2.0 mL min−1. Mobile phase composition and the gradients were optimized in order to enable efficient separation on both columns. The method using fused-core particle column provided higher separation efficiency, narrow peaks of analytes resulted in increased peak capacity and shortening of analysis time. After the validation, the method was applied for analysis of coloured beers, soft drinks and candies.

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