Pericytes of newly formed vessels in experimental subretinal neovascularization

OBJECTIVE: To examine the role of pericytes in the progression of subretinal neovascularization in a primate model. METHODS: Subretinal neovascularization was induced by intense laser photocoagulation in four monkey eyes. Single eyes were enucleated at 3, 7, 14, and 21 days after photocoagulation and were studied with light and electron microscopy. RESULTS: Three days after photocoagulation, newly formed vessels were observed in the choroid and subretinal space. Although most of these vessels had an immature appearance and consisted only of endothelial cells that formed narrow lumens, mitotic figures of pericytes were occasionally found near the endothelial cells. Seven days after photocoagulation, all of the newly formed vessels possessed pericytes. Fourteen days after photocoagulation, many vessels appeared to be mature. Many sites of pericyte-endothelial cell contact were observed. These contacts were composed of cytoplasmic interdigitation and membrane apposition. By 21 days after photocoagulation, the mature vessels had increased in number, and the endothelial cells had many fenestrations with diaphragms. The pericyte coverage of the endothelial cells was less at this stage than at 14 days after photocoagulation, and sites of pericyte-endothelial cell contacts were observed only rarely. CONCLUSION: Pericytes are involved in maturation of the endothelial cells that form subretinal new vessels.     

Experimental results on bistatic rain scattering at 14.3 GHz

A bistatic rain scatter experiment at 14.3 GHz was conducted on two scattering paths. The experiment was made for more than two years on the Kashima-Inubo path and for more than one year on the Kashima-Hiraiso path. Statistical analyses of the data were made to obtain, e.g., cumulative distributions of the received power, worst month statistics of the received power, and cumulative duration time distributions of the received power. It is found that the effect of rain attenuation reduces statistical variations of the received power. A brief discussion on the prediction of the received power is presented. Also presented are the experimental results showing that the effect of antenna polarization on the received power is well described by the Mie theory.     

Liver transplantation--present status]

Living related liver transplantation (LPLT) as well as reduced sized graft or split liver transplantation has come from the situation with donor shortage for conventional whole liver transplantation from brain dead donors (cadaveric liver transplantation; CLT). To date, about fifty thousands liver transplants have been undergone all over the world. CLT has much diversity of the original diseases, but mainly liver cirrhosis in adults and biliary atresia in children. Original diseases for LRLT have been deviated to cholestatic diseases in childhood, but now LRLT for adults and other diseases in children, i.e. fulminant hepatitis and metabolic disorders, are increasing. The survival rate of LRLT in Kyoto University for first 230 consecutive cases was 79.5%. The main cause of death was infection-related events. There are several problems in LRLT to be resolved; perioperative management of infectious complications, how to deal with the unavoidable ABO incompatible matching transplants, how to expand the national capacity of LRLT to respond the urgent transplantations. Earlier establishment of CLT program in Japan will be necessary to make the liver transplantation the beneficial procedure for more people with end stage liver diseases.     

Molecular evolution of the Amy multigenes in the subgenus Sophophora of Drosophila

Molecular evolution of the Amy multigenes in Drosophila was investigated using PCR amplification. Twenty-five partial Amy sequences from 13 species belonging mainly to the subgenus Sophophora were determine, and a molecular phylogeny of the Amy genes in Drosophila was constructed, together with published Amy sequences. Clustering of species are mostly consistent with the traditional classification and that inferred from other genes. From sequence divergence between PCR products, several species, including D. elegans and D. fuyamai, were suggested to have multiple copies of the Amy genes. The loss of an intron took place at least three times after the Sophophora radiation. In order to investigate the mechanism of sequence evolution, the numbers of amino acid replacement and synonymous substitutions in five lineages were estimated. The heterogeneity in the relative numbers of synonymous and replacement substitutions among the lineages was found. Possible roles of selection in the sequence evolution of the Amy gene are discussed.     

Surface texturing of large area multicrystalline silicon solar cells using reactive ion etching method

A reactive ion etching method has been applied to form a surface texture of multicrystalline silicon solar cells in order to reduce the surface reflectance. This surface texture has a pyramid-like shape, and aspect ratio of which can be easily controlled by the gas flow ratio.15 cm × 15 cm multicrystalline silicon solar cells have been fabricated using this texturing method and maximum conversion efficiency of 17.1% has been achieved.     

DEM simulations and experiments for projectile impacting two-dimensional particle packings including dissimilar material layers

The dynamic response of a two-dimensional ordered particle packing composed of nylon-66 spheres 6.35 mm in diameter impacted by a spherical projectile was investigated both experimentally and numerically using the discrete element method (DEM). First, the influence of the number of layers in the particle packing on wave propagation and post-impact movement were examined. As the number of layers increased, the contact forces reaching the base plate decreased together with the rebound velocity of the projectiles. Next, the effects of dissimilar material layers were examined. The spheres in one or two layers of the particle packing were replaced with spheres made of dissimilar materials, that is, alumina ceramic (Al₂O₃) or steel, and it was found that the scattering of the nylon spheres above the dissimilar material layers increased. The experimental results obtained using force sensors at the base plate showed that the dissimilar material layers reduced the contact forces at the base plate. Furthermore, as the mass of the dissimilar material spheres increased, the magnitude of the contact forces at the base plate decreased, and the rebound velocity of the projectile increased.     

Experimental study of magnetic arc blow for plasma arc cutting

Oxygen plasma arc cutting (PAC) is widely used in various industrial fields. In the case of cutting magnetized plates, the magnetic field is concentrated around the cutting front according to the progress of the cutting, and the electromagnetic force induced by leakage magnetic field deflects the plasma jet. The deflected plasma jet causes poor cutting quality and sometimes causes fatal damage on the electrode and the nozzle by a double arc as abnormal discharge. This phenomenon is called magnetic arc blow, and it is a critical issue of applying plasma cutting on magnetized plates. The purpose of this study is to investigate the arc blow behaviour and to devise a method to prevent it. We examined the relationship between operating conditions and double arc with external magnetic fields on the plasma jet. We found criteria of operation conditions that induce the arc blow. In addition, we have succeeded in suppressing the double arc generation attributed to the external magnetic field with a mild steel shield cap attachment around the nozzle tip.