Orientation of a floating right triangular prism

We describe the torque acting on right triangular prisms with equilateral, isosceles, and scalene bases that float on a liquid with their joining edges oriented parallel to the liquid surface. We derive from simple planar geometric calculations the torque as a function of buoyancy and orientation and the orientation at zero torque as a function of buoyancy. Our results are in agreement with earlier results by Czwalina that were limited to the case of right isosceles triangular prisms floating in such a way that the liquid surface intersects the two edges of the base that have equal length. We confirm our predictions experimentally and show that the orientation of floating prisms may be used for the remote determination of the density of liquids

Novel Old Yellow Enzyme subclasses

Many drug candidate molecules contain at least one chiral centre and consequently, the development of biocatalytic strategies to complement existing metal- and organocatalytic approaches is of high interest. However, time is a critical factor in chemical process development and thus, the introduction of biocatalytic steps, even if more suitable, is often prevented by the limited availability of off-the-shelf enzyme libraries. To expand the biocatalytic toolbox with additional ene reductases, we screened 19 bacterial strains for double bond reduction activity using the model substrates cyclohexanone and carvone. Overall, we identified 47 genes coding for putative ene reductases. Remarkably, bioinformatic analysis of all genes and the biochemical characterization of four representative novel ene reductases led us to propose the existence of two new Old Yellow Enzyme subclasses, which we named OYE class III and class IV. Our results demonstrate that while on a DNA level each new OYE subclass features a distinct combination of sequence motifs previously known from the classical and the thermophilic-like group, their substrate scope more closely resembles the latter subclass