Both water and electron-transfer reactions play important roles in chemistry, physics, biology, and the environment. Oxidative DNA damage is a well-known mechanism, whereas the relative role of reductive DNA damage is unknown. The prehydrated electron (e(pre)-), a novel species of electrons in water, is a fascinating species due to its fundamental importance in chemistry, biology, and the environment. e(pre)- is an ideal agent to observe reductive DNA damage. Here, we report both the first in situ femtosecond time-resolved laser spectroscopy measurements of ultrafast-electron-transfer (UET) reactions of e(pre)- with various scavengers (KNO(3), isopropanol, and dimethyl sulfoxide) and the first gel electrophoresis measurements of DNA strand breaks induced by e(pre)- and OH(•) radicals co-produced by two-UV-photon photolysis of water. We strikingly found that the yield of reductive DNA strand breaks induced by each e(pre)- is twice the yield of oxidative DNA strand breaks induced by each OH(•) radical. Our results not only unravel the long-standing mystery about the relative role of radicals in inducing DNA damage under ionizing radiation, but also challenge the conventional notion that oxidative damage is the main pathway for DNA damage. The results also show the potential of femtomedicine as a new transdisciplinary frontier and the broad significance of UET reactions of e(pre)- in many processes in chemistry, physics, biology, and the environment.

Despite intense study over the past two decades, the dynamics of electron solvation in water, particularly regarding the physical properties and lifetimes of non-equilibrium, incompletely relaxed electrons, remain very controversial. Both experimental and theoretical studies have reported a very diverse range, from approximately 50 to approximately 1000 fs, for the lifetime of the p-like excited state of the hydrated electron, and the nature of incompletely relaxed states remains unclear. Here, we reveal that these controversies are to a great extent due to a hidden effect, i.e., the universal existence of a coherence spike at delay time zero in pump-probe spectroscopic kinetics traces. After removing this spike effect, we show that the intrinsic lifetimes of the two incompletely relaxed states in bulk water are 180+/-30 and 545+/-30 fs, respectively. Moreover, our results using iododeoxyuridine as a molecular probe reveal that both states are electronically excited states of the hydrated electron and the second state of a 545 fs lifetime is the long-sought wet electron. These results resolve the long-standing controversies about electron hydration dynamics.

A spatial shift between channels in a dual-beam raster scan imaging system introduces a temporal separation between images from the two channels that can be much shorter than the frame rate of the system. The technique is demonstrated by measuring the velocity of erythrocytes in the retinal capillaries. We used an Adaptive Optics Scanning Laser Ophthalmoscope and introduced a temporal separation between imaging channels of 4.7 ms. We imaged three subjects and measured changing capillary blood flow velocity at the pulse rate. Since the time shift between channels is easily and continuously adjustable, this method can be used to measure rapidly changing events in any raster scan system with little added complexity. © 2015 Optical Society of America

PD-L1 is important in determining aggressiveness of PTC and could predict the prognosis of patients. Therefore, inhibition of PD-L1 is suggested as a potential strategy for the treatment of advanced PTC with high expression of PD-L1.

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