Fast Amide Bond Cleavage Assisted by a Secondary Amino and a Carboxyl Group-A Model for yet Unknown Peptidases?

Unconstrained amides that undergo fast hydrolysis under mild conditions are valuable sources of information about how amide bonds may be activated in enzymatic transformations. We report a compound possessing an unconstrained amide bond surrounded by an amino and a carboxyl group, each mounted in close proximity on a bicyclic scaffold. Fast amide hydrolysis of this model compound was found to depend on the presence of both the amino and carboxyl functions, and to involve a proton transfer in the rate-limiting step. Possible mechanisms for the hydrolytic cleavage and their relevance to peptide bond cleavage catalyzed by natural enzymes are discussed. Experimental observations suggest that the most probable mechanisms of the model compound hydrolysis might include a twisted amide intermediate and a rate-determining proton transfer

Genetic method for optimizing the process of desulfurization of flue gases from sulfur dioxide

Sulfur dioxide is one of the most commonly found gases, which contaminates the air, damages human health and the environment. To reduce the damage, it is important to control the emissions on power stations, as the major part of sulfur dioxide in the atmosphere is produced during electric energy generation on power plants. The present work describes flue gas desulfurization process optimizing strategy using data mining. Determining the relationship between process parameters and the actual efficiency of the absorption process is an important task for improving the performance of flue gas desulfurization plants and optimizing future plants. To predict the efficiency of cleaning from SO2 emissions, a model of wet flue gas desulfurization was developed, which combines a mathematical model and an artificial neural network. The optimization modified genetic method of flue gas desulfurization process based on artificial neural network was developed. It affords to represent the time series characteristics and factual efficiency influence on desulfurization and increase its precision of prediction. The vital difference between this developed genetic method and other similar methods is in using adaptive mutation that uses the level of population development in working process. It means that less important genes will mutate in chromosome more probable than high suitability genes. It increases accuracy and their role in searching. The comparison exercise of the developed method and other methods was done with the result that the new method gives the smallest predictive error (in the amount of released SO2) and helps to decrease the time in prediction of efficiency of flue gas desulfurization. The results allow to use this method to increase efficiency in flue gas desulfurization process and to reduce SO2 emissions into the atmosphere

Charakter der Kraftänderung beim Rohrziehen mit Ultraschall

Mittels Ultraschallschwingungen ist es nur nur möglich, die Ziehkraft beim eingestellten Prozess zu senken, sie erlauben auch eine starke Verbesserung der Umformbedingungen in der Anfangsperiode des Ziehens, was wiederum eine Erhöhung des maximalen Umformgrades des Rohrs während eines Durchgangs ermöglicht

Fast Amide Bond Cleavage Assisted by a Secondary Amino and a Carboxyl Group—A Model for yet Unknown Peptidases?

Unconstrained amides that undergo fast hydrolysis under mild conditions are valuable sources of information about how amide bonds may be activated in enzymatic transformations. We report a compound possessing an unconstrained amide bond surrounded by an amino and a carboxyl group, each mounted in close proximity on a bicyclic scaffold. Fast amide hydrolysis of this model compound was found to depend on the presence of both the amino and carboxyl functions, and to involve a proton transfer in the rate-limiting step. Possible mechanisms for the hydrolytic cleavage and their relevance to peptide bond cleavage catalyzed by natural enzymes are discussed. Experimental observations suggest that the most probable mechanisms of the model compound hydrolysis might include a twisted amide intermediate and a rate-determining proton transfer

Radiation exposure does not significantly contribute to the risk of recurrence of Chernobyl thyroid cancer.

Papillary thyroid carcinoma (PTC) in patients exposed to environmental radioiodine after the Chernobyl accident is thought to have a relatively aggressive clinical course. Long-term results of treatment are not well known, especially in comparison with sporadic PTC