Ru Complex Ion Induces Anomalous Enhancement of Electrochemical Charge Transfer

Electrochemical impedance spectroscopy (EIS) is a highly sensitive observation technique to detect the state of electrode surfaces in solution. A small amount of [Ru(bpy)2DPPZ]2+, a well-known DNA intercalator and fluorescent light switch, has been found to abnormally increase the charge transfer of the mediator [Fe(CN)6]3-/4- at the surface of carbon electrodes. When a very small amount of the Ru complex is added to the EIS solution, a large impedance decrease occurs. This phenomenon is caused by the carbon electrode, the mediator [Fe(CN)6]3-/4- and [Ru(bpy)2DPPZ]2+. No other agents are necessary. By adding [Fe(CN)6]3−/4− and a very small amount of [Ru(bpy)2DPPZ]2+ to the PCR solution, EIS measurements using a PVA-coated carbon electrode could monitor PCR progress in real-time as an increase in impedance

The ASTRO-H X-ray Observatory

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray

The Quiescent Intracluster Medium in the Core of the Perseus Cluster

Clusters of galaxies are the most massive gravitationally-bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. It can enable new insights into mechanical energy injection by the central supermassive black hole and the use of hydrostatic equilibrium for the determination of cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50 million K diffuse hot plasma filling its gravitational potential well. The Active Galactic Nucleus of the central galaxy NGC1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These likely induce motions in the intracluster medium and heat the inner gas preventing runaway radiative cooling; a process known as Active Galactic Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus cluster core, which reveal a remarkably quiescent atmosphere where the gas has a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s is found across the 60 kpc image of the cluster core. Turbulent pressure support in the gas is 4% or less of the thermodynamic pressure, with large scale shear at most doubling that estimate. We infer that total cluster masses determined from hydrostatic equilibrium in the central regions need little correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July

Hitomi (ASTRO-H) X-ray Astronomy Satellite

The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E  >  2  keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month

Synthesis and Photophysical Properties of Fluorescence Molecular Probe for Turn-ON-Type Detection of Cytosine Bulge DNA

A fluorescent molecule DANP that binds to cytosine bulge DNA and emits characteristic fluorescence was conjugated to pyrene to give a new fluorescence probe PyDANP. Temperature- and solvent-dependent absorption changes showed that DANP and pyrene chromophores stacked at room temperature in an aqueous buffer solution and quenched fluorescence. Upon binding of DANP moiety in PyDANP to cytosine bulge DNA, the fluorescence from DANP bound to C-bulge increased by ∼12-fold, showing that PyDANP is a turn-ON probe for the detection of C-bulge DNA