Proteorhodopsin (PR) and Gloeobacter rhodopsin (GR) are retinal-based light-driven proton pumps that absorb visible light (maxima at 520-540 nm). Shifting the action spectra of these proton pumps beyond 700 nm would generate new prospects in optogenetics, membrane sensor technology, and complementation of oxygenic phototrophy. We therefore investigated the effect of red-shifting analogues of re...

Error-prone PCR was used to isolate Photinus pyralis luciferase mutants producing bright light in the red-orange region of the spectrum. All mutations were clustered in the beta5-alpha10-beta6 region of N-terminal subdomain B and appear to affect bioluminescence color by modulating the position of the Ser314-Leu319 mobile loop with respect to the putative active site. Two red variants (Q283R an...

In this work, we carried out electroluminescence (EL) measurements on metallic single-walled carbon nanotubes (SWNTs) and compared the light emission from the suspended section with the on-substrate section along the same SWNT. In addition to the lowest excitonic emission for metallic SWNTs (M(11)), a side peak was observed at an energy of 0.17-0.20 eV lower than the M(11) peak, which is attrib...

magnetotelluric (mt) method is an electromagnetic method which provides information about subsurface conductivity structures using earth's natural electromagnetic fields. static shift is one of disorders arising from shallow conductors; therefore static shift must be corrected as one of mt data processing steps. in the absence of sufficient information about the near surface distortions, w...

Red-emissive carbon quantum dots with a high yield and large Stokes shift are used in luminescent solar concentrators to obtain external optical efficiency of 4.81%.

The spectroscopic behavior of colloidal InP quantum dots (QDs) has been investigated as a function of the mean QD diameter (which ranged from 26 to 60 Å). Absorption spectra show up to three peaks or shoulders which reflect excited state transitions in the QDs. Global photoluminescence (PL) spectra (excitation well to the blue of the absorption onset and which consequently excites most of the Q...

The k-calculus was advanced by Hermann Bondi as a means of explaining special relativity using only simple algebra [1]. Bondi's argument was placed in the context of classical electrodynamics. In this paper it is placed in context of particle theoretic QED. The central derivations are reviewed, using proofs only slightly more elegant than those in Bondi’s books. As used by Bondi, k is Doppler r...

A photon’s observed wavelength tells an astronomical detector about the amount of position information obtained by observing that photon. This amount of position information appears to depend on time in a way which, to first order over distances small compared to the size of the universe, may account for the cosmological red shift. Interpretation of cosmological red shift as due to rapid recess...

We investigate the impact of water on the optical absorption of prototypical silicon clusters. Our clusters contain 5 silicon atoms, tetrahedrally coordinated and passivated with either hydrogen or oxygen. We approach this complex problem by assessing the contributions of three factors: chemical reactivity, thermal equilibration, and dielectric screening. We find that the silanone (Si=O) functi...

To gain information about the properties of tyrosyl residues buried within proteins, the circular dichroism (CD) and absorption spectra of tyrosine derivatives have been investigated in nonpolar solvents. N-Stearyl-L-tyrosine n-hexyl ester dissolved in methylcyclohexane (O-O band at 283 nm) was used to measure the effects of hydrogen-bonding agents. Adding low concentrations of dioxane, N, N-di...