Artesunate/Chlorproguanil/Dapsone

The stability and high-dose addition of carbon dots in corrosion and scale inhibition are obstacles to their commercial application. Herein, we report a new type of functional CDs (PEI-CD_A) based on Angelica residue and polyethyleneimine (PEI), which can remarkably boost the performance of corrosion and scale inhibition, while expending the application of traditional Chinese medicine waste residue. At 303.15 K, the corrosion inhibition efficiency of PEI-CD_A for carbon steel in 1.0 M HCl medium was tested by weight loss method and electrochemical method and reached over 93 %, which is significantly better than that of CD_A (83 %) under the same conditions. And its corrosion inhibition efficiency can still remain stable after 15 h. The ultra-low dose (5 mg·L^-1) PEI-CD_A has excellent anti-corrosion protection effect on carbon steel due to its ability to form a dense and well-organized adsorption film covering on the carbon steel surface, whose adsorption includes two types of chemical and physical adsorption, and follows the Langmuir adsorption model. Furthermore, static methods display that the CaSO₄ scale inhibition efficiency of PEI-CD_A is up to 100 % when its dosage is 100 mg·L^-1. Analysis of the generated CaSO₄ scale shows that the addition of PEI-CD_A causes lattice distortion, chelation, and dispersion of scale. In addition, the fluorescence spectra imply that PEI-CD_A can be expected to on-line detection of its residual content in the water system. The results demonstrate that PEI-CD_A possesses significant potential in green inhibitors and the comprehensive utilization of waste resources.

Chitosan is a promising biopolymer with wide range of applications. It is the deacetylated product of chitin. Commercially, it is produced from chitin via a harsh thermochemical process that has several shortcomings and heterogenous deacetylation product. Chitin can be transformed into chitosan through enzymatic deacetylation using chitin deacetylase (CDA), enabling the production of chitosan with a specific degree of deacetylation. CDA is primarily extracted from fungi followed by bacteria and insects. The extraction of CDA from fungus is more complex, possess several health risks for human including skin lesions. Therefore, screening of potent bacterial CDA is the need of the hour. In this study, for the first time we have isolated a bacterial strain Aneurinibacillus aneurinilyticus from the rinsed water of marine crab shell, and it was found to be a potent CDA producer. The extracellular CDA from A. aneurinilyticus has been partially purified and the specific activity of the enzyme was found to be 569.73 U/ mg protein. SDS-PAGE profiling of the purified sample depicts two isomers of CDA with molecular weights of 27 kD and 45 kD. The pH and temperature optima of the purified CDA were found to be 7.4 and 37 °C, respectively. The partially purified enzyme has Km and Vmax values of 98.455 µM and 909.09 µmole/min, for non-chitinous substrate such as p-nitroacetanilide. For chitinous substrates like glycol chitin, N-acetyl glucosamine hexamer and colloidal chitin, the enzyme exhibited K_m of 96.96, 111.75 and 127.86 µM, respectively, V_max for these substrates were 23.31, 10.12 and 10.772 µmole/min, respectively. Metal ions like Mn and Mg considerably boost the production and activity of CDA, whereas Cd and Co strongly inhibit its activity. Insights from this study further substantiate that this enzyme follows Michaelis-Menten equation and has potential for industrial applications.