Reactions with 5,6-Diphenyl-2,3-dihydro-imidazo[2,1-b]thiazol-3-ones and 6,7-Diphenyl-2,3-dihydro-4H-imidazo[2,1-b]1,3-thiazin-4-one

2-Methyl-5,6-diphenyl-2,3-dihydro-imidazo[2,1-b]thiazol-3-one 5 and 6,7-diphenyl-2,3-dihydro-4H-imidazo[2,1-b]1,3-thiazin-4-one 6 are prepared from 4,5-diphenyl-2-mercapto-imidazole 1 . Compounds 5 and 6 react with amines or hydrazines to give the 2-(4,5-diphenyl-imidazol-2-ylthio)acet(or propan) amides (hydrazides) 7a – g and the 3-(4,5-diphenyl-imidazol-2 ylthio) propanamides(hydrazides) 8a – e , respectively. The hydrazides 7a, 7b and 8a are condensed with aromatic aldehydes to the hydrazones 9a – h and 10a – d . Compound 5 couples with aryldiazonium salts to give 2-arylazo-2-methyl-5,6-diphenyl-2,3-dihydro-imidazo[2,1-b]thiazol-3-ones 11a – d .     

The surrogate scaffold method for quantifying molecular release kinetics from drug delivery systems

The accurate determination of kinetics of therapeutic release from drug delivery vehicles is an essential step in the optimized design of such systems for biomedical and pharmaceutical applications. Most methods in current use for quantifying therapeutic release rates are developed to provide consistency, reproducibility, and ease of usage in a laboratory setting. These methods, however, do not necessarily mirror the release conditions when the drug delivery system comes into contact with the target tissue environment during application. As a result, the findings from these studies provide only comparative guidelines about the drug delivery rates and duration. Successful optimization of a drug delivery system requires complete, and accurate, knowledge about the release profile over an extended period of time to determine the initial release rate—including burst release if present, the rate of change of the release kinetics, and the maximum duration of delivery at a minimum therapeutic concentration level. We have developed an indirect method for the quantification of release kinetics suitable for nanoparticle-based drug delivery systems that utilizes a hydrogel scaffold as a tissue surrogate to better emulate therapeutic delivery into a target tissue environment. Details of the method and its application to the release of an angiogenic peptide from a nanoparticle emulsion are provided in this communication.     

A review of natural language processing in contact centre automation

Pattern Analysis and Applications - Contact centres have been highly valued by organizations for a long time. However, the COVID-19 pandemic has highlighted their critical importance in ensuring...     

Electrical and Dielectric Properties of Composites Composed of Natural Quartz with Aluminum

Silicon - Quartz is the most common mineral in continental crust rocks. It has been used for multiple industrial purposes. Herein, we have investigated the effect of aluminum (Al) additions on the...     

Adaptive observer design for uncertain nonlinear ODE-PDE cascades

We are revisiting the problem of adaptive observer design for systems that are constituted of an Ordinary Differential Equation (ODE), containing a globally Lipschitz function of the state, and a linear Partial Differential Equation (PDE) of a diffusion–reaction heat type. The ODE and PDE are connected in series and both are subject to parametric uncertainties. In addition to nonlinearity and uncertainty, the system complexity also lies in the fact that no sensor can be implemented at the junction point between the ODE and the PDE. In the absence of parameter uncertainty, nonadaptive state observers are available featuring exponential convergence. However, convergence is guaranteed only under the condition that either the Lipschitz coefficient is sufficiently small or the PDE domain length is sufficiently small. To get around this limitation, and also to account for parameter uncertainty, we develop a design that involves two concatenated adaptive observers, covering the two subintervals of the PDE domain. The proposed design employs one extra sensor, providing the measurement of the PDE state at an inner position close to the ODE-PDE junction point. Both observers are shown to be exponentially convergent, under ad-hoc persistent excitation (PE) conditions, with no limitation on the Lipschitz coefficient and domain length.