Galenic formulations of Cannabis sativa: comparison of the chemical properties of extracts obtained by simple protocols using lipidic vehicles.

The growing use of Cannabis sativa as a complementary therapy to allopathic medicine has brought about the modification of laws for its use worldwide. This entails the need to harmonize the methods of galenic preparations in pharmacies and cannabis-specialized non-governmental organizations as well as for self-provision as contemplated in some current legislation, such as that of Argentina. Thus, this work aimed to study simple and efficient methods to produce medicinal cannabis oils that require low-cost equipment and few handling steps. The final formulas allowed the obtaining of preparations of known concentrations of neutral cannabinoids, total polyphenol content, total flavonoid content, and antioxidant capacity. These methods allow for the selection of convenient vehicles and access to safe medicinal products of standardized quality. Our results show that cannabis extraction can be efficiently performed by directly using long-chain lipidic vehicles as extractants, resulting in a formulation with maximized oxidizing capacity and potentially extending its durability.

Stable and Reusable Fe3 O4 /ZIF-8 Composite for Encapsulation of FDH Enzyme under Mild Conditions Applicable to CO2 Reduction.

The enzymatic reduction of carbon dioxide presents limited applicability due to denaturation and the impossibility of biocatalyst recovery; disadvantages that can be minimized by its immobilization. Here, a recyclable bio-composed system was constructed by in-situ encapsulation under mild conditions using formate dehydrogenase in a ZIF-8 metalorganic framework (MOF) in the presence of magnetite. The partial dissolution of ZIF-8 in the enzyme's operation medium can be relatively inhibited if the concentration of magnetic support used exceeds 10 mg mL-1 . The bio-friendly environment for immobilization does not harm the integrity of the biocatalyst, and the production of formic acid is improved 3.4-fold compared to the free enzyme because the MOFs act as concentrators of the enzymatic cofactor. Furthermore, the bio-composed system retains 86 % of its activity after a long time of five cycles, thus indicating an excellent magnetic recovery and a good reusability.

Low intensity, continuous wave photodoping of ZnO quantum dots - photon energy and particle size effects.

The unique properties of semiconductor quantum dots (QDs) have found application in the conversion of solar to chemical energy. How the relative rates of the redox processes that control QD photon efficiencies depend on the particle radius (r) and photon energy (Eλ), however, is not fully understood. Here, we address these issues and report the quantum yields (Φs) of interfacial charge transfer and electron doping in ZnO QDs capped with ethylene glycol (EG) as a function of r and Eλ in the presence and absence of methyl viologen (MV2+) as an electron acceptor, respectively. We found that Φs for the oxidation of EG are independent of Eλ and photon fluence (φλ), but markedly increase with r. The independence of Φs on φλ ensures that QDs are never populated by more than one electron-hole pair, thereby excluding Auger-type terminations. We show that these findings are consistent with the operation of an interfacial redox process that involves thermalized carriers in the Marcus inverted region. In the absence of MV2+, QDs accumulate electrons up to limiting volumetric densities ρe,∞ that depend sigmoidally on excess photon energy E* = Eλ - EBG(r), where EBG(r) is the r-dependent bandgap energy. The maximum electron densities: ρev,∞ ∼ 4 × 1020 cm-3, are reached at E* > 0.5 eV, independent of the particle radius.

Exploiting electron storage in TiO2 nanoparticles for dark reduction of As(V) by accumulated electrons.

UV irradiation of an ethanolic sol of TiO2 nanoparticles produces a trapped Ti(III) centre and a noticeable Burstein shift. Direct evidence that the accumulated charges can drive the otherwise forbidden reduction of As(V) by conduction band electrons is presented.