Nanoparticle injection to single animal cells using femtosecond laser-induced impulsive force

An impulsive force, which was generated by focusing tightly a femtosecond laser into a cell culture medium, was applied to inject nanoparticles into local areas of a single mouse fibroblast NIH3T3 cell. When the impulsive force was induced near the cell, the nanoparticles adhering on the cell membrane were introduced, which was directly confirmed by confocal fluorescence microscopy.     

Reactivity of Highly Lewis‐Acidic Diborane(4) toward C≡N and N=N Bonds: Uncatalyzed Addition and N=N Bond‐Cleavage Reactions

The diboration of the C≡N bond in organic nitriles, and the N=N bond in azobenzene and pyridazine, by the highly Lewis‐acidic tetra(o‐tolyl)diborane(4) are reported. In the reactions with nitriles, azobenzene, and pyridazine, the addition of diborane(4) to the C≡N and N=N bonds was observed. Conversely, the N=N bond in phthalazine was cleaved by an addition/rearomatization sequence.     

Study of distribution of 203Hg-chlormerodrin, 203Hg-nitrate and 99mTc-DMSA in kidney by macroautoradiography (author's transl)]

Serial macroautoradiograms were obtained to determine the distribution of 203Hg-chlormerodrin, 203Hg-nigrate and 99mTc-DMSA in kidney. In the study, normal rats were used and these three radiopharmaceuticals were injected intravenously. Initial images of 203Hg-chlormerodrin showed the accumulation in the outer cortex, but no significant radioactivity in the medullary. On the other hand, delayed images revealed radioactivity shifting in concentration from the outer cortex to the inner cortex. Distribution pattern of 203Hg-nitrate was similar to that of 203Hg-chlormerodrin. In contrast to 203Hg-chlormerodrin and 203Hg-nitrate, 99mTc-DMSA was retained in the outer cortex without temporal changes in the distribution.     

Role of hydrogen atoms in anodized porous silicon

Hydrogen atoms chemisorbed in anodized porous silicon (PS) during anodization in a HF solution have been investigated by using both experimental techniques and a semi-empirical calculation method. The results show important roles of chemisorbed H atoms in PS on anodization mechanisms and a slight expansion of Si-Si bond length, as in the case of the structural change and low-temperature oxidation process of PS films previously reported. Fine structures observed in the infrared absorption band of the Si-H stretching vibrations can be related to charge redistributions of H-chemisorbed Si atoms which were calculated for various clusters with Si_nH_m using the AM1 method. The calculation results on the Si-Si bond length in the clusters are also consistently explained in relation to slight increases in the lattice constant of PS: the origin comes from Si charges attracted by chemisorbed H atoms on the pore walls.     

Collapse of charge order in a quasi-one-dimensional organic conductor with a quarter-filled band

A charge-ordered insulator, (DI-DCNQI)2Ag, with a quasi-one-dimensional quarter-filled band is metallized by pressure. It was found that the charge order melts into a curious metallic state with cubic-temperature dependence of the resistivity, which implies the unprecedented mechanism of the electron-electron scattering. We constructed the pressure-temperature phase diagram, where the melting line has a tricritical point dividing the second-order line at low pressures and the first-order line at high pressures just before it vanishes.     

Electronic states of silicon in Ni-silicides by nuclear magnetic resonance

Spin-lattice relaxation time (T₁) of ²⁹Si nuclei in several Ni-silicides (Ni_1?xSi_x:0.25?x?0.67) were studied at low temperature (1.4?T?4.2 K) by spin-echo technique. The relation of T₁T = const. and also very short T₁ were observed indicating that the silicides studied were metallic with enough densities of state of 3s-electrons at the Fermi energy (E_F). Another feature of the results was that T₁ decreased with the increment of silicon concentration. This effect was discussed in connection with the soft X-ray spectroscopy (SXS) data on Ni-silicides and Ni—Al compounds.     

Whole-body retention studies of 167Tm-citrate.--Estimation of radiation dose to human from 167Tm-citrate--(author's transl)]

For the purpose of calculating absorbed dose to humans from 167Tm-citrate, the whole-body retention studies using 5 rats were carried out. Up to 40 days following intravenous injection of 167Tm-citrate, the whole-body counts were monitored with a animal counter. The whole-body retention curve was obtained with three exponentaial components. Namely, the 26% of the injected 167 Tm-citrate had a biological half-time of 3.4 hours, 12.5% had a biological half-time of 99 hours and 61.5% had a biological half-time of 106 days. These results indicate, that three components consist of the rapid clearance from the kidneys, the retention in the liver and other soft tissues with relatively long half-time and the retention in the bones with long half-time. Based on these biological data and the MIRD Committee method, the average dose estimates to the bone and whole-body from intravenous administration of 1 mCi 167Tm-citrate were 7.08 rads and 1.28 rads, respectively.     

Distance-regular subgraphs in a distance-regular graph, II

Let Γ be a distance-regular graph with r = l(1, a₁, b₁), a₁ > 0 and c_2r+1 = 1. We show the existence of a collinearity graph of a Moore geometry of diameter r + 1 as a subgraph in Γ. In particular, we show that r = 1.     

Synthesis, structural transformation, thermal stability, valence state, and magnetic and electronic properties of PbNiO3 with perovskite- and LiNbO3-type structures

We synthesized two high-pressure polymorphs PbNiO(3) with different structures, a perovskite-type and a LiNbO(3)-type structure, and investigated their formation behavior, detailed structure, structural transformation, thermal stability, valence state of cations, and magnetic and electronic properties. A perovskite-type PbNiO(3) synthesized at 800 °C under a pressure of 3 GPa crystallizes as an orthorhombic GdFeO(3)-type structure with a space group Pnma. The reaction under high pressure was monitored by an in situ energy dispersive X-ray diffraction experiment, which revealed that a perovskit-type phase was formed even at 400 °C under 3 GPa. The obtained perovskite-type phase irreversibly transforms to a LiNbO(3)-type phase with an acentric space group R3c by heat treatment at ambient pressure. The Rietveld structural refinement using synchrotron X-ray diffraction data and the XPS measurement for both the perovskite- and the LiNbO(3)-type phases reveal that both phases possess the valence state of Pb(4+)Ni(2+)O(3). Perovskite-type PbNiO(3) is the first example of the Pb(4+)M(2+)O(3) series, and the first example of the perovskite containing a tetravalent A-site cation without lone pair electrons. The magnetic susceptibility measurement shows that the perovskite- and LiNbO(3)-type PbNiO(3) undergo antiferromagnetic transition at 225 and 205 K, respectively. Both the perovskite- and LiNbO(3)-type phases exhibit semiconducting behavior.