Molecular and Enzymatic Characterization of Flavonoid 3'-Hydroxylase of × .

× (apple) accumulates particularly high amounts of dihydrochalcones in various tissues, with phloridzin (phloretin 2'--glucoside) being prevalent, although small amounts of 3-hydroxyphloretin and 3-hydroxyphloridzin are also constitutively present. The latter was shown to correlate with increased disease resistance of transgenic × plants. Two types of enzymes could be involved in 3-hydroxylation of dihydrochalcones: polyphenol oxidases or the flavonoid 3'-hydroxylase (F3'H), which catalyzes B-ring hydroxylation of flavonoids.

Simple Determination of Gold Nanocrystal Dimensions by Analytical Ultracentrifugation via Surface Ligand-Solvent Density Matching.

Analytical ultracentrifugation (AUC) is a powerful technique to observe colloidal nanocrystals (NCs) directly in solution and obtain critical information about their physical-chemical properties. Nevertheless, a more comprehensive implementation of AUC for the characterisation of such a class of crystalline colloids has been traditionally impaired by the requirement of having a priori knowledge of the complex, multilayered structure formed by NC in solution. This includes the nature (density and mass) of the surface ligands (SLs) that provide NC colloidal stability and the shell of solvent molecules formed on it.

Tuning the properties of hydrogels made from poly(acrylic acid) and calcium salts.

Hydrogels consisting of poly(acrylic acid) (PAA) and calcium ions are a promising class of materials with shapeable, stretchable and self-healing behaviour originating from the reversible and dynamic nature of the electrostatic and hydrogen bonds in the structure. In the dry state, such materials - referred to as "mineral plastics"- can be transparent, hard and flame-resistant, while addition of water will result in rehydration and complete recoverage of the initial gel-like state. These desirable characteristics strongly depend on the molar mass of the used type of PAA and the experimental conditions at which the hydrogels are prepared.

Nucleation of Hematite: A Nonclassical Mechanism.

Hematite (α-Fe O ) is thermodynamically stable under ambient conditions, of vast geological importance, and widely used in applications, for example, as corrosion protection and as a pigment. It forms at elevated temperatures, whereas room-temperature reactions typically yield metastable akaganéite or ferrihydrite. The mechanistic key changes underlying this observation were explored in the present study.