Kinetics of charge transfer in DNA containing a mismatch

Charge transfer (CT) in DNA offers a unique approach for the detection of a single-base mismatch in a DNA molecule. While the single-base mismatch would significantly affect the CT in DNA, the kinetic basis for the drastic decrease in the CT efficiency through DNA containing mismatches still remains unclear. Recently, we determined the rate constants of the CT through the fully matched DNA, and we can now estimate the CT rate constant for a certain fully matched sequence. We assumed that further elucidating of the kinetics in mismatched sequences can lead to the discrimination of the DNA single-base mismatch based on the kinetics. In this study, we investigated the detailed kinetics of the CT through DNA containing mismatches and tried to discriminate a mismatch sequence based on the kinetics of the CT in DNA containing a mismatch

CO_2, water, and sunlight to hydrocarbon fuels: a sustained sunlight to fuel (Joule-to-Joule) photoconversion efficiency of 1%

If we wish to sustain our terrestrial ecosphere as we know it, then reducing the concentration of atmospheric CO_2 is of critical importance. An ideal pathway for achieving this would be the use of sunlight to recycle CO_2, in combination with water, into hydrocarbon fuels compatible with our current energy infrastructure. However, while the concept is intriguing such a technology has not been viable due to the vanishingly small CO_2-to-fuel photoconversion efficiencies achieved. Herein we report a photocatalyst, reduced blue-titania sensitized with bimetallic Cu–Pt nanoparticles that generates a substantial amount of both methane and ethane by CO_2 photoreduction under artificial sunlight (AM1.5): over a 6 h period 3.0 mmol g^(−1) methane and 0.15 mmol g^(−1) ethane are obtained (on an area normalized basis 0.244 mol m^(−2) methane and 0.012 mol m^(−2) ethane), while no H_2 nor CO is detected. This activity (6 h) translates into a sustained Joule (sunlight) to Joule (fuel) photoconversion efficiency of 1%, with an apparent quantum efficiency of φ = 86%. The time-dependent photoconversion efficiency over 0.5 h intervals yields a maximum value of 3.3% (φ = 92%). Isotopic tracer experiments confirm the hydrocarbon products originate from CO_2 and water

Long-Range Charge Transfer through DNA by Replacing Adenine with Diaminopurine

A pos. charge migrates along DNA mainly via a series of short-range charge transfer (CT) processes between G-C base pairs, which have relatively high HOMO levels. As such, the CT efficiency sharply decreases with the insertion of A-T base pairs between the G-C base pairs. We have previously demonstrated that the CT efficiency through DNA can be dramatically increased by using deazaadenine (Z), an analog of A, to adjust the HOMO levels of the A-T base pairs closer to those of the G-C base pairs (Nat. Chem. 2009, 1, 156). In the present study, we have expanded this approach to show that the CT efficiency can also be increased by replacing A bases with diaminopurine (D).A pos. charge migrates along DNA mainly via a series of short-range charge transfer (CT) processes between G-C base pairs, which have relatively high HOMO levels. As such, the CT efficiency sharply decreases with the insertion of A-T base pairs between the G-C base pairs. We have previously demonstrated that the CT efficiency through DNA can be dramatically increased by using deazaadenine (Z), an analog of A, to adjust the HOMO levels of the A-T base pairs closer to those of the G-C base pairs (Nat. Chem. 2009, 1, 156). In the present study, we have expanded this approach to show that the CT efficiency can also be increased by replacing A bases with diaminopurine (D).identifier:oai:t2r2.star.titech.ac.jp:5067355

FREE JET INFRARED ABSORPTION SPECTROSCOPY OF THE ν6\nu_{6} AND ν7\nu_{7} BANDS OF IRON PENTACARBONYL

The larger linewidth observed in the $\nu_{6}$ band is attributed to the inhomogeneous broadening inherent to the spatial inhomogeneity in a free jet. The influence of the dense background levels to the $\nu_{6}$ band is found to be a minor effect.Author Institution: The Institute of Physical and Chemical ResearchThe infrared diode laser absorption spectra of $\nu_{6}$ (CO stretching, $2038.10 cm^{-1}$) and $\nu_{7}$ (CO bending, $619.94 cm^{-1}$) bands of $Fe(CO)_{5}$ have been studied in a supersonic free jet. Owing to several low frequency vibrational modes, the vibrational level density at $\nu_{6}=1$ is as high as $\sim 5 \times 10^{4}/cm^{-1}$, while the density at $\nu_{7}= 1$ is only $\sim 20/cm^{-1}$. In spite of the large difference in background vibrational level density, both bands show the similar rotational structure characteristic to the parallel band of symmetric top molecules

알루미나 절연막으로 코팅된 이산화티타늄을 이용한 염료감응 태양광 전환 소재 연구

2