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Minimal osteonecrosis (MON) is a small and eccentrically localized lesion of osteonecrosis (ON) of the femoral head. This form of ON shows clinically benign features, but may be indicative of the pathomechanism of ON. Of 180 patients (275 hips) with ON, 15 patients (19 hips) were found to have MON. Based on the geography of the femoral head, the lesions were grouped into four types: anterior (seven hips), superior (six hips), medial (five hips), and lateral (one hip). When the location of the lesion was compared with the normal vascular anatomy, a close correlation between the location and the segmental blood supply in the femoral head became evident. Histologic findings showed localized infarction of the trabeculae and bone marrow, but no evidence suggesting repeated episodes of infarction, which is an essential feature of typical ON. From these findings, MON may be a segmental infarct within the femoral head. Interruption of the blood flow may possibly occur not in the main trunk but in the terminal branch of the lateral epiphyseal or superior metaphyseal artery; such as ischemic event is probably a single brief attack, leading to this form of infarction in contrast to typical ON developing with prolonged or recurrent obstructions.

We have studied several decay processes of potassium clusters and found that a dimer-decay mechanism can explain the observed lowest abundance of K10 in the K n mass spectra. Total-energy curves for decay processes are calculated using a jellium-background model for positive-ion cores and the local-spin-density-functional approximation for valence electrons. The energy-barrier height for a dimer decay of K10 from the energy-minimum point is found to be 0.18 eV, which is a reasonable magnitude for the decay to take place thermally in the experiment. The monomer decay of K9, and the dimer decay of K11, which are expected to be the most favorable decays of K9 and K11, are found to have high barriers. Monomer and dimer decays of K8 are also studied and the monomer decay is found to be more favorable, in accord with the high-nozzle-temperature mass spectrum.

We have calculated the total energies of n-atom potassium clusters ${\mathrm{K}}_{\mathrm{n}}$ (1\ensuremath{\le}n\ensuremath{\le}23) using a jellium-sphere background model for the positive-ion cores and the local-spin-density-functional approximation for the valence electrons. We find that the K clusters which have exoergic fission channels have low abundances in the experimental mass spectra indicating the presence of thermal fissions of ${\mathrm{K}}_{\mathrm{n}}$. Most of the exoergic fissions are found to produce dimers, ${\mathrm{K}}_{2}$, as one of the daughter clusters. We have studied the ``dimer decay'' of ${\mathrm{K}}_{10}$ in an attempt to explain why ${\mathrm{K}}_{10}$ is one of the least abundant clusters in the ${\mathrm{K}}_{\mathrm{n}}$ mass spectra. Two overlapping jellium spheres with constant density are used for the positive background. The energy-barrier height for complete decay from the energy-minimum point is found to be 0.18 eV, which is a reasonable magnitude for thermal decay compared to the experimental temperature. The monomer decay of ${\mathrm{K}}_{9}$ and the dimer decay of ${\mathrm{K}}_{8}$ are found to have higher barriers.

We have studied core biopsy specimens from 16 femoral heads affected by idiopathic avascular necrosis at the silent stage, when there were no clinical or radiographic manifestations but scintigraphy was positive. All the specimens showed necrosis of trabeculae and of bone marrow, but the most common and characteristic feature was evidence of old and new haemorrhage in the marrow. In the areas of intramedullary haemorrhages, trabeculae and bone marrow were completely necrotic, with a transitional area of incomplete necrosis between these areas and those without haemorrhagic lesions, where the trabeculae and bone marrow were normal. There was good correlation between necrosis and haemorrhagic episodes, and it was concluded that repeated intramedullary haemorrhage at the silent stage is probably related to the pathogenesis of idiopathic avascular necrosis of the femoral head.

We introduce here a strategy that enables effective addition of lithium enolates of acetates to aldimines. The new method depends strongly on the use of o-alkoxy (or o-fluoro) aniline-derived aldimines which have been found to have a potential effect on the enolate addition. This scope was expanded to the asymmetric process using the chiral acetate. A Lewis acid additive has a complementary role in the pronounced activation of imine functionalities.

3-D ionospheric tomography by using measurements of ground GNSS networks is a powerful tool to investigate ionospheric behavior. Recently, a real-time 3-D ionosphere tomography system has been developed [1] to reconstruct 3-D ionospheric density profiles over Japan. 3-D ionospheric density profiles over Japan estimated by a real-time 3-D tomography system, which is available from March 2016 were used to generate ionospheric correction for single-frequency stand-alone positioning. On both magnetic quiet and disturbed days (14 November 2017 and 25 October 2017, respectively), stand-alone positioning corrected by real-time tomography resulted in mean vertical errors equivalent to those of dual-frequency positioning. The RMS vertical errors of stand-alone positioning corrected by real-time tomography were better than those of dual-frequency positioning and equivalent to those of uncorrected single-frequency positioning. More analysis on data sets at different location, in different seasons, and in different magnetic conditions are planned. Although there is no specific plan, it is also interesting to apply the same method to other locations where GNSS receiver networks with the similar receiver density as used in this study.

The work function is one of the crucial quantities in understanding their field emission properties and applying carbon nanotubes to electronic devices. We perform the systematic study of work functions of 44 kinds of isolated single-walled carbon nanotubes in the framework of the density functional theory. It has been revealed that the first-principles study plays a very important role for predicting various properties of carbon nanotubes. In general, we have to perform the structural relaxation in order to know the accurate electronic properties of carbon nanotubes. Therefore we carry out the complete geometrical relaxations for 44 kinds of carbon nanotubes and evaluate their work functions. The diameters (D) of nanotubes studied satisfy 0.3 < D < 2.0 nm. Especially, we focus on the small diameter carbon nanotubes. We determine the values of work functions from the difference between the Fermi level and the vacuum level. In the semiconducting carbon nanotubes, the Fermi level is chosen at the midgap. As a result, it is found that the carbon nanotubes should be classified into three classes according to the diameter and chiral-angle dependences of work functions.

The present paper covers the progress in stereo-, regio-, and chemoselective carbon- carbon bond-forming reactions promoted by structurally well-designed aluminum aryloxides. Compared with conventional Lewis acids, these aluminum reagents strongly coordinate with various oxygen-containing substrates, and the coordination aptitude is strongly affected by the steric environment of the metal ligands. In principle, the carbonyl groups of the bound substrates are electronically activated but sterically deactivated depending on the aluminum reagent and the type of the reaction employed. This review specifically highlights the selective organic reactions using ATPH.

Diastereoselective vinylogous direct aldol reaction was realized by use of chiral α,β-unsaturated esters and aldehydes in the presence of aluminum tris[2,6-bis(4-alkylphenyl)phenoxide]s. The reaction involves novel 1,7-asymmetric induction and direct coupling of an α,β-unsaturated ester with an aldehyde, through in situ deprotonation of the γ-proton of the ester component by LTMP.

We calculate the structural and electronic properties of an ordered ``bundle'' of (10,10) carbon nanotubes. Our results indicate that intertube coupling causes an additional band dispersion of $\ensuremath{\lesssim}0.2 \mathrm{eV}$ and opens up a pseudogap of the same magnitude at ${E}_{F}.$ Soft librations at $\ensuremath{\nu}\ensuremath{\approx}12 {\mathrm{cm}}^{\ensuremath{-}1}$ are predicted to occur below the orientational melting temperature which marks the onset of tube rotations about their axis. Whereas the density of states near ${E}_{F}$ increases by 7% due to intertube coupling and by one order of magnitude due to K doping in ${\mathrm{KC}}_{8},$ these states do not couple to tube librations.

A proline-derived silanol, was designed as a novel potential organocatalyst, and synthesized starting from the tetrazole 3. The central idea was the combination of an acidic (tetrazole) and a basic functionality (pyrrolidine) with a silanol moiety in the same molecule. The synthesis of 7 was performed in four reaction steps starting with the tetrazole 3. In the solid state (X-ray crystal structure analysis) the crucial functional groups show a favorable orientation. A chiral HPLC method and a chiral capillary electrophoresis method have been established for the investigation of the kinetic resolution of the racemic alcohols 9 and 11. Acetylation reactions of alcohols were not accelerated by the organocatalyst 7, and the produced ee values were rather low.

Time rates of growing and damping of resistive instability in gaseous plasma in crossed fields are measured. The discharge tube used is a coaxial cylindrical type with a grid. By means of an external excitation of damping waves or an observation of the transient of self‐excitation of waves by an abrupt change of the magnetic field strength, the damping or the growth rates can be determined. The results thus obtained agree with those indicated theoretically.

For reappraisal of total hip arthroplasty (THA) in the treatment of nontraumatic osteonecrosis (ON) of the femoral head, 29 hips in 23 patients with ON were surveyed in a comparison with 63 osteoarthritic (OA) hips treated in the same manner during the same period; the hips were selected according to the same criteria. The 29 ON hips were followed for an average of seven years. Comparing the ON and OA groups, the patient profiles were similar, except for weight and sex. For the ON group, hip scores according to the Merle D'Aubigne system (18 points for a normal hip) were improved from 9.8 preoperatively to 14.3 at the latest survey. However, 14 hips (48%) presented unsatisfactory clinical results, and roentgenologically all showed aseptic component loosening. Such a failure rate was higher than that for the OA group (33%); similarly, femoral component loosening occurred more frequently in the ON (28%) than in the OA group (5%). Based on the analysis of the patient profiles, Stage 3 ON at surgery, bilateral occurrence of the disease and bilateral THA could have caused such a failure in the ON group. In addition, most of the hips with component loosening showed histologic evidence of extensive bone necrosis within the resected femoral head. ON is a high-risk disease in terms of the long-term durability of THA, the failure of which seems to be mainly caused by extensive necrosis.