Темплатный метод синтеза монодисперсных наночастиц MoS-=SUB=-2-=/SUB=-

Monodisperse molybdenum disulfide nanoparticles were synthesized in mesopores of spherical silica particles (mSiO2) served as a template. First, the pores of mSiO2 particles were impregnated with the precursor (ammonium tetrathiomolybdate solution). Then, the reduction of the filler in thermodynamically equilibrium conditions in H2S/H2 atmosphere was carried out. The template material (a-SiO2) was selectively etched from the composite mSiO2/MoS2 particles with HF to obtain individual MoS2 nanoparticles. The mean size of MoS2 nanoparticles determined by microscopic methods was found to be 3.5 nm. According to dynamic light scattering data, the nanoparticles had low size scatter (18%).

Natural Products Isolated from Oriental Medicinal Herbs Inactivate Zika Virus

Zika virus (ZIKV) has been associated with serious health conditions, and an intense search to discover different ways to prevent and treat ZIKV infection is underway. Berberine and emodin possess several pharmacological properties and have been shown to be particularly effective against the entry and replication of several viruses. We show that emodin and berberine trigger a virucidal effect on ZIKV. When the virus was exposed to 160 µM of berberine, a reduction of 77.6% in the infectivity was observed; when emodin was used (40 µM), this reduction was approximately 83.3%. Dynamic light scattering data showed that both compounds significantly reduce the hydrodynamic radius of virus particle in solution. We report here that berberine and emodin, two natural compounds, have strong virucidal effect in Zika virus.

Hydrodynamic Parameters of Strelitzia Gum

The flower of Strelitzia reginae generates abundant and viscous mucilage as exudate, which is purified in periods of heating–cooling, and finally precipitated with ethanol, obtaining strelitzia gum (StrG). By means of intrinsic viscosity measurement, the viscometric molecular weight (MWv) is determined, with a value of 200,000 g/mol, as well as a hydrodynamic radius of 20 ± 1 nm and a hydration value of 445 ± 34 g/g. The size of StrG was compared against dynamic light scattering data with a value of 16 ± 2 nm and a MWDLS of 230,000 g/mol. StrG is a biopolyelectrolyte with an “a” value of 0.85, which corresponds to a flexible behavior with a great effect of volume exclusion. This statement is based on the difficulty of gum dissolution, that should be performed at 80 °C. This macromolecule is very promising and can potentially be used in several industrial applications, such as in film forming, and as a gel, thickener, and coemulsifier.