213 research outputs found
Universal rates for reactive ultracold polar molecules in reduced dimensions
Analytic expressions describe universal elastic and reactive rates of
quasi-two-dimensional and quasi-one-dimensional collisions of highly reactive
ultracold molecules interacting by a van der Waals potential. Exact and
approximate calculations for the example species of KRb show that stability and
evaporative cooling can be realized for spin-polarized fermions at moderate
dipole and trapping strength, whereas bosons or unlike fermions require
significantly higher dipole or trapping strengths.Comment: 4 pages, 3 figure
Nanophotonic engineering of far-field thermal emitters
Thermal emission is a ubiquitous and fundamental process by which all objects
at non-zero temperatures radiate electromagnetic energy. This process is often
presented to be incoherent in both space and time, resulting in broadband,
omnidirectional light emission toward the far field, with a spectral density
related to the emitter temperature by Planck's law. Over the past two decades,
there has been considerable progress in engineering the spectrum,
directionality, polarization, and temporal response of thermally emitted light
using nanostructured materials. This review summarizes the basic physics of
thermal emission, lays out various nanophotonic approaches to engineer
thermal-emission in the far field, and highlights several relevant
applications, including energy harvesting, lighting, and radiative cooling.Comment: Review articl
A novel-type luciferin from Siberian luminous earthworm Fridericia heliota : structure elucidation by spectral studies and total synthesis
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Wiley-VCH Verlag GmbH & Co for personal use, not for redistribution. The definitive version was published in Angewandte Chemie International Edition 53 (2014): 5566–5568, doi:10.1002/anie.201400529.We report structure elucidation and synthesis of the luciferin from the recently discovered luminous earthworm Fridericia heliota. This luciferin represents a key component of a novel ATP-dependent bioluminescence system. The UV, fluorescence, NMR and HRMS spectral studies were performed on 5 mkg of the isolated substance, and gave four isomeric structures, conforming with spectral data. These isomers were chemically synthesized and one of them was found to produce light in the reaction with a protein extract from Fridericia. The novel luciferin was found to have an unusual deeply modified peptidic nature, implying an unprecedented mechanism of action.We acknowledge support from the Program of the Government of the Russian Federation “Measures to attract leading scientists to Russian educational institutions” (grant no. 11. G34.31.0058), the programs MCB RAS, President of the Russian Federation “Leading science school” (grant 3951.2012.4) and the Russian Foundation for Basic Research (grant 14-03-01015). B.M.S. was supported by a stipend from the Program of the President of the Russian Federation.2015-04-1
- …