Photo-oxygenation of Indene and 1,2-Dihydronaphthalene: Formation of 1,2-Dioxetanes and 1,2,4-Trioxanes

The methylene blue (MB)-sensitized photo-oxygenation of indene (1) in CH3OH gave trans-2-hydroperoxy-1-methoxyindane (9), homophthalaldehyde (4), and its cyclic acetal 8. The same reaction conducted in acetaldehyde gave only 4. Repetition of the photo-oxygenation of 1 in slightly acidic aq. acetone (1:9) gave essentially trans-2-hydroperoxy-1-hydroxyindane (14) together with some cis-5,6-dihydro-3,3-dimethyl-1,2,4-trioxinol[1,2-e]indene. The MB-sensitized photo-oxygenation of 1,2-dihydronaphthalene (16) in CH3OH gave l,4-dihydro-1-hydroperoxynaphthalene (17) and trans-l,2,3,4-tetrahydro-2-hydroperoxy-1-methoxynaphthalene (19). In acetaldehyde, 16 furnished only 17. In aq. acetone (1:9) 16 gave 17 and trans-2-hydroperoxy-1-hydroxy-1,2,3,4-tetrahydronaphthalene (23). Product compositions were rationalized in terms of the 2-peroxides of the 1-cation of 1 and 16, namely 11 and 20. Treatment of 23 with aldehydes and ketones on catalysis with Amberlyst-15 or trimethylsilyl trifluoromethanesulfonate afforded the trans-fused 1,2,4-trioxanes 25. The 1,2-dioxetanes of 1 and 16 condensed with acetaldehyde on catalysis with CF3COOH to give the cis-fused 1,2,4-trioxanes 12 and 22

Development and Performance of Kyoto's X-ray Astronomical SOI pixel (SOIPIX) sensor

We have been developing monolithic active pixel sensors, known as Kyoto's X-ray SOIPIXs, based on the CMOS SOI (silicon-on-insulator) technology for next-generation X-ray astronomy satellites. The event trigger output function implemented in each pixel offers microsecond time resolution and enables reduction of the non-X-ray background that dominates the high X-ray energy band above 5--10 keV. A fully depleted SOI with a thick depletion layer and back illumination offers wide band coverage of 0.3--40 keV. Here, we report recent progress in the X-ray SOIPIX development. In this study, we achieved an energy resolution of 300~eV (FWHM) at 6~keV and a read-out noise of 33~e- (rms) in the frame readout mode, which allows us to clearly resolve Mn-K$\alpha$ and K$\beta$. Moreover, we produced a fully depleted layer with a thickness of $500~{\rm \mu m}$. The event-driven readout mode has already been successfully demonstrated.Comment: 7pages, 12figures, SPIE Astronomical Telescopes and Instrumentation 2014, Montreal, Quebec, Canada. appears as Proc. SPIE 9147, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ra

Soft X-ray radiation damage in EM-CCDs used for Resonant Inelastic X-ray Scattering

Advancement in synchrotron and free electron laser facilities means that X-ray beams with higher intensity than ever before are being created. The high brilliance of the X-ray beam, as well as the ability to use a range of X-ray energies, means that they can be used in a wide range of applications. One such application is Resonant Inelastic X-ray Scattering (RIXS). RIXS uses the intense and tuneable X-ray beams in order to investigate the electronic structure of materials. The photons are focused onto a sample material and the scattered X-ray beam is diffracted off a high resolution grating to disperse the X-ray energies onto a position sensitive detector. Whilst several factors affect the total system energy resolution, the performance of RIXS experiments can be limited by the spatial resolution of the detector used. Electron-Multiplying CCDs (EM-CCDs) at high gain in combination with centroiding of the photon charge cloud across several detector pixels can lead to sub-pixel spatial resolution of 2–3 μm. X-ray radiation can cause damage to CCDs through ionisation damage resulting in increases in dark current and/or a shift in flat band voltage. Understanding the effect of radiation damage on EM-CCDs is important in order to predict lifetime as well as the change in performance over time. Two CCD-97s were taken to PTB at BESSY II and irradiated with large doses of soft X-rays in order to probe the front and back surfaces of the device. The dark current was shown to decay over time with two different exponential components to it. This paper will discuss the use of EM-CCDs for readout of RIXS spectrometers, and limitations on spatial resolution, together with any limitations on instrument use which may arise from X-ray-induced radiation damage

Single-shot 3D coherent diffractive imaging of core-shell nanoparticles with elemental specificity.

We report 3D coherent diffractive imaging (CDI) of Au/Pd core-shell nanoparticles with 6.1 nm spatial resolution with elemental specificity. We measured single-shot diffraction patterns of the nanoparticles using intense x-ray free electron laser pulses. By exploiting the curvature of the Ewald sphere and the symmetry of the nanoparticle, we reconstructed the 3D electron density of 34 core-shell structures from these diffraction patterns. To extract 3D structural information beyond the diffraction signal, we implemented a super-resolution technique by taking advantage of CDI's quantitative reconstruction capabilities. We used high-resolution model fitting to determine the Au core size and the Pd shell thickness to be 65.0 ± 1.0 nm and 4.0 ± 0.5 nm, respectively. We also identified the 3D elemental distribution inside the nanoparticles with an accuracy of 3%. To further examine the model fitting procedure, we simulated noisy diffraction patterns from a Au/Pd core-shell model and a solid Au model and confirmed the validity of the method. We anticipate this super-resolution CDI method can be generally used for quantitative 3D imaging of symmetrical nanostructures with elemental specificity

女子大生からみるキレイ顔の要因

This research examined what are the factors of beautiful face in women’s university student. The samples were face pictures of female that showed in various mass media. The subjects are total 200 women’s students. First, the boundary line of a beautiful face and an ugly face was clarified. Next, we could find there are some factors of beautiful woman’s face. These factors are“ height of eyes", "width of eyes", "diameter of pupil", "distance of left and right eye" and "length under nose". Especially, "distance of left and right eye" of a beautiful face is narrower than an ugly face, and it is 25-26% in relation to the width of face

Atomic resolution structure of serine protease proteinase K at ambient temperature

Atomic resolution structures (beyond 1.20 ?) at ambient temperature, which is usually hampered by the radiation damage in synchrotron X-ray crystallography (SRX), will add to our understanding of the structure-function relationships of enzymes. Serial femtosecond crystallography (SFX) has attracted surging interest by providing a route to bypass such challenges. Yet the progress on atomic resolution analysis with SFX has been rather slow. In this report, we describe the 1.20 ? resolution structure of proteinase K using 13 keV photon energy. Hydrogen atoms, water molecules, and a number of alternative side-chain conformations have been resolved. The increase in the value of B-factor in SFX suggests that the residues and water molecules adjacent to active sites were flexible and exhibited dynamic motions at specific substrate-recognition sites. ? 2017 The Author(s).114Ysciescopu

Hydroxyethyl cellulose matrix applied to serial crystallography

Serial femtosecond crystallography (SFX) allows structures of proteins to be determined at room temperature with minimal radiation damage. A highly viscous matrix acts as a crystal carrier for serial sample loading at a low flow rate that enables the determination of the structure, while requiring consumption of less than 1 mg of the sample. However, a reliable and versatile carrier matrix for a wide variety of protein samples is still elusive. Here we introduce a hydroxyethyl cellulose-matrix carrier, to determine the structure of three proteins. The de novo structure determination of proteinase K from single-wavelength anomalous diffraction (SAD) by utilizing the anomalous signal of the praseodymium atom was demonstrated using 3,000 diffraction images. ? 2017 The Author(s).113Ysciescopu