Single-photon laser spectroscopy of cold antiprotonic helium

Some laser spectroscopy experiments carried out by the Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA) collaboration to measure the single-photon transition frequencies of antiprotonic helium (\(\overline {p}\text {He}^{+}\equiv \overline {p}+\text {He}^{2+}+e^{-}\)) atoms are reviewed. The \(\overline {p}\text {He}^{+}\) were cooled to temperature T =?1.5–1.7 K by buffer-gas cooling in a cryogenic gas target, thus reducing the thermal Doppler width in the single-photon resonance lines. The antiproton-to-electron mass ratio was determined as \(M_{\overline {p}}/m_{e}=?1836.1526734(15)\) by comparisons with the results of three-body quantum electrodynamics calculations. This agreed with the known proton-to-electron mass ratio.     

Epitaxial growth of Sc-doped ZnO films on Si by sol-gel route

The epitaxial growth of doped ZnO films is of great technological importance. Present paper reports a detailed investigation of Sc-doped ZnO films grown on (1 0 0) silicon p-type substrates. The films were deposited by sol-gel technique using zinc acetate dihydrate as precursor, 2-methoxyethanol as solvent and monoethanolamine (MEA) as a stabilizer. Scandium was introduced as dopant in the solution by taking 0.5 wt%¹ of scandium nitrate hexahydrate. The effect of annealing on structural and photoluminescence properties of nano-textured Sc-doped films was investigated in the temperature range of 300-550 °C. Structural investigations were carried out using X-ray diffraction, scanning electron microscopy and atomic force microscopy. X-ray diffraction study revealed that highly c-axis oriented films with full-width half maximum of 0.21° are obtained at an annealing temperature of 400 °C. The SEM images of ZnO:Sc films have revealed that coalescence of ZnO grains occurs due to annealing. Ostwald ripening was found to be the dominant mass transport mechanism in the coalescence process. A surface roughness of 4.7 nm and packing density of 0.93 were observed for the films annealed at 400 °C. Room temperature photoluminescence (PL) measurements of ZnO:Sc films annealed at 400 °C showed ultraviolet peak at about (382 nm) with FWHM of 141 meV, which are comparable to those found in high-quality ZnO films. The films annealed below or above 400 °C exhibited green emission as well. The presence of green emission has been correlated with the structural changes due to annealing. Reflection high energy electron diffraction pattern confirmed the nearly epitaxial growth of the films.     

Measurement of the antiproton-nucleus annihilation cross-section at very low energies

The ASACUSA collaboration at the Antiproton Decelerator at CERN is planning to measure the hyperfine splitting of the ground state of antihydrogen using an atomic beam line. This will be a measurement of the antiproton magnetic moment, and also a test of the CPT invariance. The planned experimental method and setup, including the radiofrequency resonance cavity, are described, and results of Monte Carlo simulations are shown. These simulations predict that the antihydrogen ground-state hyperfine splitting can be determined with a relative precision of ～10^???7.     

Psoas Muscle Volume and Attenuation are Better Predictors than Muscle Area for Hospital Readmission in Older Patients after Transcatheter Aortic Valve Implantation

Objective: This study aimed to determine whether the psoas muscle volume (PMV) and its muscle attenuation (MA) are associated with hospital readmission after transcatheter aortic valve implantation (TAVI). Method: We included 113 older patients with aortic stenosis who underwent TAVI at Sakakibara Heart Institute (mean age 85 ± 5 years, 69% women). We measured PMV and psoas muscle area (PMA) as well as total muscle area (TMA) at the third lumbar vertebra using preoperative computed tomography (CT) images. The crude values of the PMV, PMA, and TMA were normalized by dividing by height squared. Results: The median follow-up period was 724 days (interquartile range: 528-730 days), and there were 25 all-cause readmissions during the follow-up period (22% of all patients). In the multivariate Cox regression analysis adjusted for age, sex, and EuroSCORE II, the PMV and its MA and crude PMA were significantly associated with all-cause readmission [HR: 0.957 (0.930-0.985), p = 0.003, HR: 0.927 (0.862-0.997), p = 0.040], whereas the PMA and TMA and each MA were not (all p > 0.05). The groups with low PMV and MA had significantly higher incidences of all-cause readmission than that with high PMV and MA (log-rank test: p = 0.011). Conclusion: PMV and its MA measured from preoperative CT images were independent predictors of all-cause readmission in TAVI patients.     

New agents for alkoxycarbonylation of amines

Alkoxycarbonylated pyrazinols and pyrazinethiols were prepared. These compounds were shown to be convenient agents for alkoxycarbonylation of aliphatic amines.     

Novel 4-phenoxy-2-(1-piperazinyl)quinazolines as potent anticonvulsive and antihypoxic agents

A series of 4-phenoxy-2-(1-piperazinyl)quinazolines was synthesized and examined for anticonvulsive and antihypoxic activities. Many of the compounds exhibited potent anticonvulsive activity comparable to that of carbamazepine or phenytoin. Among them, 4-phenoxy-2-(4-propyl-1-piperazinyl)quinazoline (5w) was selected as the most promising candidate antiepileptic drug with few side effects. It seemed that potent anticonvulsive activity was a prerequisite for potent antihypoxic activity.     

Deuterium N.M.R. studies of polypeptides I. Sidechain orientation in poly(γ-benzyl L-glutamate) and the mechanism of the cholesteric sense inversion

The mechanism of thermally- and solvent-induced cholesteric sense inversions in lyotropic polypeptide liquid crystals has been discussed based on deuterium N.M.R. observations for poly(γ-benzyl L-glutamate) with perdeuteriated sidechain benzyl ester groups. Comparison of the deuterium quadrupolar splitting pattern with the macroscopic helical twisting power indicates that the sense inversion does not necessarily require sidechain conformational transitions (or changes in the helix surface chirality). The new data support a less specific mechanism for sense determination in polypeptide liquid crystals: anisotropic intermolecular interactions between helices are influenced by the solvent dielectric medium.     

Regiospecific synthesis of γ-hydroxybutenolide. Photosensitized oxygenation of substituted 2-trimethylsilylfuran

Regiospecific synthesis of substituted γ-hydroxybutenolide was accomplished by photosensitized oxygenation of 2-trimethylsilyl-furan derivatives, and chemoselective oxidation of furan ring having tri- and tetra-substituted olefins in the side chain was also achieved.