There is a close connection between modern-day biosynthesis of particular triterpenoid biomarkers and presence of molecular oxygen in the environment. Thus, the detection of steroid and triterpenoid hydrocarbons far back in Earth history has been used to infer the antiquity of oxygenic photosynthesis. This prompts the question: were these compounds produced similarly in the past? In this paper,...

this paper investigates the mechanism of water transportation through aquaporin-4(aqp4) of ratbrain cells by means of molecular dynamics simulation with charmm software. the aqp4 wasembedded into a bilayer made of dimystroilphosphatylcholine (dmpc). the results illustrate thatwater molecules move through aqp4's channel with change of orientation of oxygen of eachwater molecule.

The aerobic oxidation of alcohols was efficiently completed in high conversion and selectivity using Cu3/2[PMo12O40]/SiO2 as catalyst under mild reaction condition. This reaction provides a new environmentally friendly rout to the conversion of alcoholic function to carbonyl groups.

We propose a new transition state for oxygen in silica. This state is produced by the insertion of an oxygen molecule into the Si − O − Si bond, i.e. it consists of producing a Si−O−O−O−Si bond. This state allows molecular oxygen diffusion in silica without breaking the molecular O2 bond and it is energetically more stable than a peroxy configuration. This configuration may allow for exchange o...