Application of ceramic coating to improve abrasive wear resistance of die inserts used to press-mould stampings of refractories

The paper presents results of a study on abrasive wear resistance of die inserts for composite moulds used to pressmould stampings from refractory materials, determined based on susceptibility to scratching with a diamond indenter. For the study, two inserts of high-chromium cast iron were prepared, of which one was provided with a ceramic coating (60 % Al2O3 + 40 % TiO2) with a metallic interlayer (NiAlCrSi). Both layers were deposited by means of the Atmospheric Plasma Spraying (APS) method. The obtained scratch test results indicate that with the use of the same load force (20 N), die inserts with ceramic coating are characterized with less indenter penetration depth which should translate to higher resistance to abrasive wear

Abrasive wear resistance of a quenched and sub-zero treated high-chromium white cast iron

The study reported in this paper concerned development of such microstructure of high-chromium (24 % Cr) cast iron which could secure high abrasive wear resistance of die inserts used to fabricate stampings from refractory materials. It was found that by increasing the cast iron cooling rate as a result of thermal interaction with the chill, it is possible to obtain fine carbide precipitates with diversified morphology, rich in Cr and Fe, containing Mo and Si. The matrix in the regions of thermal interaction with the chill was enriched in Cr and Mo, but depleted of Fe and Si. The sub-zero treatment process was developed to secure presence of hardening products in the matrix. The obtained structure of high-chromium cast iron has made the inserts more resistant to abrasive wear compared to tool steels after hear treatment used earlier

Esterase-sensitive prodrugs of a potent bisubstrate inhibitor of Nicotinamide N-Methyltransferase (NNMT) display cellular activity

Microbial Biotechnolog

Hepatoselective Nitric Oxide (NO) Donors, V-PYRRO/NO and V-PROLI/NO, in Nonalcoholic Fatty Liver Disease: A Comparison of Antisteatotic Effects with the Biotransformation and Pharmacokinetics

ABSTRACT V-PYRRO/NO [O(2)-vinyl-1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate] and V-PROLI/NO (O2-vinyl-[2-(carboxylato)pyrrolidin-1-yl]diazen-1-ium-1,2-diolate), two structurally similar diazeniumdiolate derivatives, were designed as liver-selective prodrugs that are metabolized by cytochrome P450 isoenzymes, with subsequent release of nitric oxide (NO). Yet, their efficacy in the treatment of nonalcoholic fatty liver disease (NAFLD) and their comparative pharmacokinetic and metabolic profiles have not been characterized. The aim of the present work was to compare the effects of V-PYRRO/NO and V-PROLI/NO on liver steatosis, glucose tolerance, and liver fatty acid composition in C57BL/6J mice fed a high-fat diet, as well as to comprehensively characterize the ADME (absorption, distribution, metabolism and excretion) profiles of both NO donors. Despite their similar structure, V-PYRRO/NO and V-PROLI/NO showed differences in pharmacological efficacy in the murine model of NAFLD. V-PYRRO/NO, but not V-PROLI/NO, attenuated liver steatosis, improved glucose tolerance, and favorably modified fatty acid composition in the liver. Both compounds were characterized by rapid absorption following i.p. administration, rapid elimination from the body, and incomplete bioavailability. However, V-PYRRO/NO was eliminated mainly by the liver, whereas V-PROLI/NO was excreted mostly in unchanged form by the kidney. V-PYRRO/NO was metabolized by CYP2E1, CYP2C9, CYP1A2, and CYP3A4, whereas V-PROLI/NO was metabolized mainly by CYP1A2. Importantly, V-PYRRO/NO was a better NO releaser in vivo and in the isolated, perfused liver than V-PROLI/NO, an effect compatible with the superior antisteatotic activity of V-PYRRO/NO. In conclusion, V-PYRRO/NO displayed a pronounced antisteatotic effect associated with liver-targeted NO release, whereas V-PROLI/NO showed low effectiveness, was not taken up by the liver, and was eliminated mostly in unchanged form by the kidney

Abrasive wear resistance of a quenched and sub-zero treated high-chromium white cast iron

The study reported in this paper concerned development of such microstructure of high-chromium (24 % Cr) cast iron which could secure high abrasive wear resistance of die inserts used to fabricate stampings from refractory materials. It was found that by increasing the cast iron cooling rate as a result of thermal interaction with the chill, it is possible to obtain fine carbide precipitates with diversified morphology, rich in Cr and Fe, containing Mo and Si. The matrix in the regions of thermal interaction with the chill was enriched in Cr and Mo, but depleted of Fe and Si. The sub-zero treatment process was developed to secure presence of hardening products in the matrix. The obtained structure of high-chromium cast iron has made the inserts more resistant to abrasive wear compared to tool steels after hear treatment used earlier