X-ray irradiation synthesis of PEG-coated Au-Pd nanoparticles

We demonstrate that the combination of x-ray irradiation and capping by polyethylene glycol (PEG) produces excellent flexibility in controlling the structure of Au-Pd nanoparticles while preserving their catalytic performance. We specifically adopted two different fabrication methods: co-reduction and seed-assisted reduction. In both cases, precursor composition plays an important role in controlling the phases and size of the bimetallic nanoparticles. The optimal catalytic performance is obtained with the highest Pd concentration and when the nanoparticles consist of a Au core and a Pd shell.

Uncapped Au–Pd colloidal nanoparticles show catalytic enhancement

Au–Pd nanoparticles were produced without capping agents. The simple one-pot X-ray irradiation synthesis method yields excellent and flexibly controllable nanoparticles, and their catalytic performance is related to the Pd content.

Optimization of gold nanoparticle photoluminescence by alkanethiolation

Synthesis of photoluminescent Au nanoparticles was optimized by alkanethiolate coatings.

Firefly light flashing: oxygen supply mechanism

Firefly luminescence is an intriguing phenomenon with potential technological applications, whose biochemistry background was only recently established. The physics side of this phenomenon, however, was still unclear, specifically as far as the oxygen supply mechanism for light flashing is concerned. This uncertainty is due to the complex microscopic structure of the tracheal system: without fully knowing its geometry, one cannot reliably test the proposed mechanisms. We solved this problem using synchrotron phase contrast microtomography and transmission x-ray microscopy, finding that the oxygen consumption corresponding to mitochondria functions exceeds the maximum rate of oxygen diffusion from the tracheal system to the photocytes. Furthermore, the flashing mechanism uses a large portion of this maximum rate. Thus, the flashing control requires passivation of the mitochondria functions, e.g., by nitric oxide, and switching of the oxygen supply from them to photoluminescence.