Desilicated NaY zeolites impregnated with magnesium as catalysts for glucose isomerisation into fructose

The impact of desilication on the performance of a series of alkali-treated NaY zeolites impregnated with 5 wt.% of magnesium for glucose isomerisation into fructose has been studied. Desilication at different NaOH concentrations increases the mesoporous volume and external surface area, without compromising microporosity and crystallinity. The observed reduction of the microporous volume due to magnesium impregnation was found to decrease for the alkali-treated zeolites. Higher density and strength of basic sites and stronger magnesium-support interaction were also achieved with the treatment. These improved properties resulted in a significant increase of both glucose conversion and fructose yield on the magnesium-doped desilicated zeolites. Glucose conversion continuously increases with desilication (28–51%), whereas fructose yield passes through a maximum (35%) at low desilication levels. Among the prepared desilicated samples, low-severity alkali-treated zeolites also show lower deactivation in consecutive reaction runs, as well as superior regeneration behaviour. Thus, hierarchical NaY zeolites impregnated with magnesium could be favourably used for glucose isomerisation into fructose if suitable alkaline treatment conditions are selected, with low-severity treated NaY zeolites being the best choice. Higher fructose productivities were achieved for the low-severity desilicated zeolites than for higher magnesium content NaY zeolites reported previously, leading to a lower Mg requirement

The role of microvesicles in tissue repair

Microvesicles (MVs) are released by almost all cells in resting and activated conditions. First described several years ago, it is only recently that their mechanisms of action are being elucidated, and their potential role in health and disease is drawing increasing attention. The main function of MVs is signaling through specific interactions with target cells and the transferring of gene products. Gaining further insights into the molecular specificity of MVs has allowed identification of the cellular source and may provide new diagnostic tools in the future. Indeed, an increasing body of evidence indicates that MVs are capable of mediating tissue repair in models of acute kidney and liver injury. In this review, we will discuss the mechanisms through which MVs from stem cells may act on target cells and may modify the response to injury. Furthermore, MVs from inflammatory cells are suspected to be involved in various diseases, such as cardiovascular and renal diseases, pathological pregnancy, tumors and sepsis. MVs are no doubt also involved in modulating immunity, and future studies will clarify their functional role in negatively modulating the cell response. Their role in physiological and pathological processes is increasingly appreciated. Depending on the cell source and the condition, MVs may be either beneficial or detrimental to the host. The recognition of their pathogenetic role may suggest new approaches to future therapies