Transmission electron microscopy imaging of individual functional groups of fullerene derivatives

Mobility and reactivity of the functionalized fullerenes with pyrrolidine (C60-C3NH7) incorporated in single-wall carbon nanotubes were examined by high-resolution transmission electron microscopy. An individual functional group attached to each fullerene cage is unambiguously visualized. This provides a direct evidence for the functionalized structure on a single-molecular basis. A rotational motion of the incorporated molecules tends to occur during the observation and, consequently, each fullerene molecule is likely to stand facing its functionalized group towards the nanotube wall. A fine structure analysis of electron energy-loss spectra for the nitrogen K(1s) edge shows a considerable change in the nitrogen chemical state and suggests a strong tube-fullerene interaction.     

Dynamics of cavitation bubbles generated by multi-pulse laser irradiation of a solid target in water

The effect of the second and later pulses on the expansion dynamics of the cavitation bubble produced by multi-pulse microchip laser irradiation of a Cu target in water has been investigated. We clarified the bubble dynamics by taking shadowgraph images and measuring the bubble radius as a function of time. Shock waves were also measured to investigate the explosive expansion of the bubble. As a result, the second and later pulses did not cause an explosive expansion, and the ablation of the target by these pulses was rather mild, although they had a certain contribution to the expansion of the bubble. The energies given to the bubble expansion from the first pulse and also from the second pulse were estimated by comparing the experimental results with the calculation based on the Rayleigh model.     

Deforming hyperbolic hexagons with applications to the arc and the Thurston metrics on Teichmüller spaces

For each right-angled hexagon in the hyperbolic plane, we construct a one-parameter family of right-angled hexagons with a Lipschitz map between any two elements in this family, realizing the smallest Lipschitz constant in the homotopy class of this map relative to the boundary. As a consequence of this construction, we exhibit new geodesics for the arc metric on the Teichmüller space of an arbitrary surface of negative Euler characteristic with nonempty boundary. We also obtain new geodesics for Thurston’s metric on Teichmüller spaces of hyperbolic surfaces without boundary. Our results generalize results obtained in the two papers by Papadopoulos and Théret (Proc. Am. Math. Soc. 138(5):1775–1784, 2010 and Geom. Dedic. 161:63–83, 2012).     

Alkoxide-Induced Reaction of 1-[(Trimethylsilyl)-Methyl]Azoles with Imines and Carbonyl Compounds

t-BuOK-induced reaction of 1-[(trimethylsilyl)methyl]-1,2,4-triazole with imines to yield (triazol-1- yl)ethylamines and (triazol-5-yl)methylamines was explored. Also, alkoxide-induced desilylation of 1-[(trimethylsilyl)methyl]azoles in the presence of carbonyl compounds was demonstrated, and (-BuOK and potassium trimethylsilanolate were found to be effective in this reaction.     

Chiroptical spectra of a series of tetrakis((+)-3-heptafluorobutylyrylcamphorato)lanthanide(III) with an encapsulated alkali metal ion: circularly polarized luminescence and absolute chiral structures for the Eu(III) and Sm(III) complexes

The luminescence and circularly polarized luminescence (CPL) spectra of M(I)[Eu((+)-hfbc)(4)] show a similar behavior to the exciton CD in the intraligand π-π* transitions when the alkali metal ions and solvents are manipulated. There is a difference in susceptibility in solvation toward the alkali metal ions but not toward the Eu(III) ion, as in the case of axially symmetric DOTA-type compounds. The remarkable CPL in the 4f-4f transitions provide much more information on the stereospecific formation of chiral Eu(III) complexes, since CPL spectroscopy is limited to luminescent species and reflects selectively toward helicity of the local structural environment around the lanthanide(III). While in comparison, exciton CD reveals the chiral structural information from the helical arrangement of the four bladed chelates. Of special importance, the observation of the highest CPL activities measured to date for lanthanide(III)-containing compounds (i.e., Eu and Sm) in solution supports the theory that the chirality of lanthanide(III) in the excited state corresponds to that in the ground state, which was derived from the exciton CD.     

Characterization of Fine Hydroxyapatite Powders Synthesized by Wet Process

Abstract

We prepared fine hydroxyapatite powders by dropping ammonium bi-phosphate into a calcium acetate solution and by vigorously stirring at 3O°C. We measured the powders' specific surface area to be 290 m²/g by the BET technique. The powders were mono-dispersed ultrafine particles by transmission electron microscopy investigation. No phase other than hydroxyapatite (JCPDS: 9–432) was revealed by X-ray diffractometry. A quantitative chemical analysis gave a Ca/P ratio very close to the exact hydroxyapatite stoichiometry (Ca/P: 1.67). Shrinkage started up to 800°C according to a dilatometric measurement and the dense products were obtained when heated at 1000°C for 2 h in air. We used a quadrupole mass spectrometer to monitor the gases desorbed from the hydroxyapatite powders at a constant heating rate of 5°C/min in a high vacuum. It is noted here that there were two peaks of H₂O and CO₂, respectively, and that we observed an increase in desorption of H₂. The two peaks were explained clearly with an infrared spectrometry analysis and a thermal analysis we made separately.     

Sol-Gel Technology as Reflected in Journal of Sol-Gel Science and Technology

Journal of Sol-Gel Science and Technology started as unique journal devoted to sol-gel science and technology in 1993. First, papers so far published in the Journal were intoduced. It was shown that the titles of invited papers and special issues show the broadening of the sol-gel area. Second, the change of the research tendency was conjectured from the four proceedings volumes. It was shown that the increase of importance of a particular class of materials and appearance of emergent materials are reflected in the title of the paper.     

Thermally Stabilized Fiber-Bragg-Grating Vibration Sensor Using Servo Motor Control

A fiber-Bragg-grating (FBG) vibration sensor, in which an FBG acts as an intensity-modulator for incident narrow spectrum light such as a laser, is thermally stabilized. Sensitivity of the sensor is kept constant over a wide range of temperature by feeding back a fraction of the output signal into the laser source in such a way that by shifting the oscillation wavelength of the laser the dc component of the detected photocurrent remains unchanged regardless of change in the environmental temperature. Variation in the sensor sensitivity is reduced to as small as 3 dB after the stabilization, although it is more than 55 dB without the stabilization.     

Determination of oxycodone and hydrocotarnine in cancer patient serum by high-performance liquid chromatography with electrochemical detection.

We developed an HPLC procedure using electrochemical detection for the quantitation of oxycodone and hydrocotarnine in cancer patients serum. An eluent of methanol:acetonitrile:5 mM pH 8 phosphate buffer (2:1:7) was used for the mobile phase. The calibration curve was linear in the range from 10 ng/mL to 100 ng/mL. The recovery of oxycodone and hydrocotarnine was 97.2% and 90.5%, respectively. The relative standard deviations within-runs and between-runs for the assay of oxycodone or hydrocotarnine were less than 4.8%. The method developed here was better than the method reported previously.