The rapid scientific interest in gut microbiota (GM) has coincided with a global increase in the prevalence of infectious and non-infectivous liver diseases. GM, which is also called “the new virtual metabolic organ”, makes axis with a number of extraintestinal organs, such as kidneys, brain, cardiovascular, and the bone system. The gut-liver axis has attracted greater attention in recent years. GM communication is bi-directional and involves endocrine and immunological mechanisms. In this way, gut-dysbiosis and composition of “ancient” microbiota could be linked to pathogenesis of numerous chronic liver diseases such as chronic hepatitis B (CHB), chronic hepatitis C (CHC), alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), development of liver cirrhosis, and hepatocellular carcinoma (HCC). In this paper, we discuss the current evidence supporting a GM role in the management of different chronic liver diseases and potential new therapeutic GM targets, like fecal transplantation, antibiotics, probiotics, prebiotics, and symbiotics. We conclude that population-level shifts in GM could play a regulatory role in the gut-liver axis and, consequently, etiopathogenesis of chronic liver diseases. This could have a positive impact on future therapeutic strategies.

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The effect of niobium and vanadium additions (0.5 mass% and 2 mass%) on the as-cast microstructure and properties of hypoeutectic white cast iron containing 19 mass% Cr and 2.9 mass% C, has been examined. NbC carbides present in the structure of tested Fe-Cr-CNb alloys, due to their characteristic morphology, show higher wear resistance and toughness than M7C3 carbides. Increasing amount of this type of carbides, caused by the increase of niobium in the alloy, contributes to the improvement of wear resistance and dynamic fracture toughness. The alloy containing 2% Nb gives the best compromise between wear resistance and fracture toughness. This alloy shows about 23% greater dynamic fracture toughness and about 25% greater abrasion wear resistance than the basic Fe-Cr-C alloy. Besides, the secondary carbides which precipitate in the matrix regions of the tested Fe-Cr-C-V white irons also influence the abrasion behaviour and fracture toughness. The alloy containing 0.5% V has approximately the same fracture toughness but lower wear resistance than alloy with 2% Nb.

Experimental results indicate that vanadium affects the solidification process in high chromium iron. Vanadium is distributed between eutectic M 7 C 3 carbide and the matrix, but its content in carbide is considerably higher. Also, this element forms vanadium carbide. TEM observation reveals that vanadium carbide present in examined Fe-Cr-C-V alloys is being of M 6 C 5 type. DTA analysis found that with increasing vanadium content in tested alloys, liquidus temperature is decreasing, while eutectic temperature is increasing, i.e. the solidification temperature interval reduces. The narrowing of the solidification temperature interval and the formation of larger amount of vanadium carbides, as a result of the increase in the vanadium content of the alloy, will favour the appearance of a finer structure. In addition, the phases volume fraction will change, i.e. the primary -phase fraction will decrease and the amount of M 7 C 3 carbide will increase.

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