The stability of vitamin C in powdered mixes for beverages]

Factors influencing vitamin C stability in powder mixtures for beverages were studied and the main ways of its decomposition in products preserved in glass containers or paper packages covered with polymeric film were established. The phenomenon of vitamin C self-stabilization has been observed.     

Contrast-Free FLIM Reveals Metabolic Changes in Pathological Islets of Langerhans

FLIM (Fluorescence Lifetime Imaging Microscopy) is a powerful tool that could be used in the future to diagnose islet cell recovery after therapy. The identification of appropriate FLIM parameters is required to determine islet quality and islet cell metabolism throughout the organ under various conditions of insulin deficiency. The aim of the work was to identify key FLIM parameters, changes of which are characteristic of pancreatic pathologies. The τm, τ1, τ2, α1, α2 and α1/α2 of free and bound forms of NAD(P)H of the islet cells of animals (rats and pigs) and of humans with and without pathologies were measured and analyzed. The data were confirmed by IHC and histological studies. We identified three FLIM parameters in islet cells from animals with streptozotocin (STZ)-induced diabetes mellitus (DM) and from humans with chronic pancreatitis + type 2 diabetes (T2D), which differ in the same way: τm and α2 take lower values compared to the nonpathological islet cells, while α1/α2 takes higher values. In islet cells from patients with adenocarcinoma (PDAC) and chronic pancreatitis, these parameters had reverse tendency relative to the norm or did not differ. Thus, minimally invasive and non-contrast FLIM methods may, in the future, be used to diagnose pathological islet cells.     

The new set of apparatus of the state primary standard of the units of heat of combustion and specific and volume heat of combustion

The results of research, carried out at the Mendeleev All-Russia Research Institute of Metrology in 2007–2010 to improve the standard base of Russia, are presented. This research resulted in the design and approval of a new generation of equipment, unique in the world, as the State Primary Standard of the units of heat of combustion - the joule, the specific heat of combustion - the joule per kilogram and the volume heat of combustion - the joule per cubic meter. The composition of the standard and its metrological characteristics are considered.     

Et3GeN(SiMe3)2 and Et3SnN(SiMe3)2: New precursors for chemical vapor deposition processes

We have synthesized the germanium- and tin-containing organosilicon compounds Et₃GeN(SiMe₃)₂ and Et₃SnN(SiMe₃)₂ as new precursors for the preparation of materials by chemical vapor deposition. The compounds were characterized by NMR, IR and UV spectroscopies and thermal analysis. Using vapor pressure measurements, we obtained temperature dependences of their saturated vapor pressure. We assessed their thermal stability and calculated the thermodynamic characteristics of vaporization of the organosilicon compounds.