Liquid-crystal adaptive optics based on feedback interferometry for high-resolution retinal imaging

A novel, to our knowledge, adaptive optical imaging system for high-resolution retinal imaging is described. The system is based on a feedback interferometer, in which two-dimensional output fringe intensity from a Mach-Zehnder interferometer with large radial shear is fed back, with the help of a video projector connected with a CCD camera, to an optically addressed phase-only liquid-crystal spatial light modulator. Experiments to verify the system performance have been conducted by use of an artificial eye consisting of a lens, an aberration plate, and a resolution test target. We observed that an image of the test target (mimicking a retina) blurred by the aberration plate (mimicking ocular aberrations) was successfully restored immediately after our adaptive optics system was activated.     

Synthesis of Si nanocones using rf microplasma at atmospheric pressure

We report the synthesis of silicon nanocones using the rf microplasma discharge at atmospheric pressure. The products formed underneath the tube electrode on Fe-coated crystalline silicon were constituted mainly of silicon and silicon oxide despite the use of a methane-argon mixture. Carbon nanotubes and silicon nanowires were also formed around the silicon nanocones. The number density and average size of silicon nanocones increased with the plasma exposure time accompanied by the enlargement of their surface distribution. The growth mechanism of silicon nanocones is discussed in terms of the catalytic growth via diffusion of silicon through FeSi_x nanoclusters with nanocrystalline Si particle, and Si oxidation due to the plasma heating.     

MD simulations of amorphous SiO2 thin film formation in reactive sputtering deposition processes

Silicon Dioxide (SiO₂) thin film deposition processes were studied with the use of classical Molecular Dynamics (MD) simulations combined with Monte Carlo (MC) simulations. The MC simulations are shown to efficiently emulate thermal relaxation processes during deposition. Dependence of deposited film properties on the incident kinetic energies is examined from the numerical simulations.     

Liver tumor targeting of drugs: Spherex, a vascular occlusive agent

In order to determine whether the donor-specific T cell allorepertoire evaluated in patients before transplantation can be predictive for kidney graft survival, a study has been set up in which the number and activation state of donor-specific T lymphocytes before transplantation were correlated to transplant survival time. Limiting dilution analysis assays were carried out to determine precursor frequencies of both T helper and cytotoxic T lymphocytes. The activation state of these cells was studied by evaluating the inhibitory capacity of cyclosporine on helper and cytotoxic T cells and/or a monoclonal antibody directed against CD8 on cytotoxic T cells. This study shows that neither a significant difference in the number nor activation state of donor-directed helper and cytotoxic T cells before transplantation could be detected when patients who acutely rejected their grafts were compared with patients who still had a well-functioning kidney graft after more than 10 years. Moreover, no significant differences in the donor-specific T cell repertoire were found when patients who had been subject to multiple rejection episodes were compared with patients who experienced few complications after transplantation. Therefore, we conclude that in individuals who have not been sensitized to HLA antigens of the donor, the donor-specific peripheral T cell allorepertoire prior to transplantation is not predictive of kidney graft survival.     

A method for screening polyphosphate-accumulating mutants which remove phosphate efficiently from synthetic wastewater

The biological process for phosphorus removal from wastewater is based on the use of bacteria capable of accumulating inorganic polyphosphate (polyp). We previously showed that a phoU mutation leads to polyp accumulation in Escherichia coli. The phoU mutant could be easily screened on agar plates containing 5-bromo-4-chloro-3-indolyl-phosphate (X-P(i)) after N-methyl-N'-vitro-N-nitrosoguanidine (NTG) mutagenesis. Here, we demonstrate that this method is also useful for screening polyp-accumulating mutants of bacterial strains isolated from soil and activated sludge samples.     

An assay of ganglioside using fluorescence image analysis on a thin-layer chromatography plate

A new and simple fluorometric method for determine quantities of gangliosides ranging from pico- to nanomoles is reported. Spraying hydrochloric acid followed by a heating treatment, sugars (glucose, galactose, fucose, N-acetylgalactosamine, N-acetylglucosamine, N-acetylneuraminic acid (sialic acid)), gangliosides (G(M1), G(D1a), G(T1b)), and asialoganglioside (asialoG(M1)) on thin-layer chromatography plates produced fluorescence under 365-nm UV light. This fluorescence production of each sample was greatly dependent on the heating temperature. As sialic acid fluoresced readily at lower temperature (approximately 90 degrees C), we were able to distinguish sialic acid easily from other sugars tested. To determine gangliosides based on this sialic acid fluorescence, calibration curves for gangliosides were obtained by high-performance thin-layer chromatography and the image-analyzing system equipped with a CCD camera. The observed fluorescence images were analyzed using image-analyzing software packages and the determined calibration curves for ganglioside-bound sialic acids were reproducible and showed a high linearity in a wide range from 47 pmol to 4.5 nmol. Since the fluorescence from sialic acid is easily measurable on TLC plates and is sensitive over a wide range of sample concentration, the present method is applicable for quantitative determination of gangliosides.     

Endomitotic diploidization of Saccharomyces cerevisiae by heat treatment during spore germination

Diploid cells with ability to mate, hereafter referred to as diploid mater cells, were obtained at significant frequencies by the heat treatment of haploid spores at the early germination stage in Saccharomyces cerevisiae heterothallic strain CG5M ( a /α diploid cells heterozygous for five auxotrophic markers). The highest frequency (ca. 11%) of diploidization was obtained from viable cells after heat treatment at 55°C for 10 min when spores were precultivated for 30 min in liquid medium to initiate the germination. The diploid mater cells obtained were homozygous for mating type and for the auxotrophic markers. The diploidization of a spore is thus concluded to be due to endomitotic events in germinating heat-treated spores.     

The insulo-acinar portal and insulo-venous drainage systems in the pancreas of the mouse, dog, monkey and certain other animals: a scanning electron microscopic study of corrosion casts

Scanning electron microscopy of vascular casts of the pancreas from monkies, cattle, pigs, dogs, cats, rabbits, guinea pigs and mice showed certain species differences in the occurrence of intralobular and interlobular islets and in the microcirculatory pattern of these islets. Interlobularly located islets were frequently found in the mouse and guinea pig, as has been previously established in the rat (Murakami and Fujita, 1992); they emitted insulo-venous efferent vessels directly draining into veins. In contrast, the intralobular islets in the guinea pig usually issued insulo-acinar portal vessels continuous with the lobular capillary network. In the mouse, they usually emitted both the insulo-acinar portal and insulo-venous efferent vessels. The insulo-venous efferent vessels, including those of the interlobular islets, could partly be portal in nature since they occasionally issued portal branches directed to the lobular capillary network. In rabbits, cats, dogs, pigs, cattle and monkies, as in men (Murakami et al., 1992), essentially all islets in the pancreas were intralobular in location and usually emitted the portal vessels only. In the mouse and rabbit, as in the rat (Murakami and Fujita, 1992), the islet received afferent vessels in its superficial aspect and issued efferent vessels from its deep aspect. In the Formosan monkey, as previously reported in the rhesus monkey (Fujita and murakami, 1973), the afferent vessels usually ran deep into the islet which emitted vessels from its superficial aspect. In other animals examined in this study, as in humans (Murakami et al., 1992), no consistent rule concerning the microcirculatory pattern within the islet could be determined.