Drusenoid Pigment Epithelial Detachment: Genetic and Clinical Characteristics

Few studies report drusenoid pigment epithelial detachment (DPED) in Asians. In this multicenter study, we report the clinical and genetic characteristics of 76 patients with DPED, and, for comparison, 861 patients with exudative age-related macular degeneration (AMD) were included. On the initial presentation, the mean best-corrected visual acuity was 0.087 ± 0.17 (logMAR unit), and mean DPED height and width were 210 ± 132 and 1633 ± 1114 µm, respectively. Fifty-one (67%) patients showed macular neovascularization in the contralateral eye. The risk allele frequency of both ARMS2 A69S and CFH I62V was significantly higher in DPED than in typical AMD and polypoidal choroidal vasculopathy (PCV) (ARMS2 A69S risk allele frequency: DPED 77% vs. typical AMD 66% vs. PCV 57%, CFH I62V risk allele frequency: DPED 87% vs. typical AMD 73% vs. PCV 73%), although the risk allele frequency of both genes was similar between the DPED group and retinal angiomatous proliferation (RAP) group (ARMS2 A69S: p = 0.32, CFH I62V, p = 0.11). The prevalence of reticular pseudodrusen (RPD) was highest in RAP (60%), followed by DPED (22%), typical AMD (20%), and PCV (2%). Although the prevalence of RPD differs between DPED and RAP, these entities share a similar genetic background in terms of ARMS2 and CFH genes.     

X-ray technique for observation of ice lens growth in partially frozen,saturated soil

This paper reports observations on ice lens growth in partially frozen, saturated soil, and applications for the measurement of hydraulic conductivity in the frozen zone. The authors developed an experimental apparatus using an X-ray technique to observe the ice lens growth and measure the amount of dilatation due to the ice segregation in the sample (Yoneyama et al., 1983). The water flow rate was determined with the displacement of the lead spheres embedded in the sample under several overburden pressures and temperature gradients. The hydraulic conductivity in the frozen zone of the sample was calculated from the water flow rates in the frozen zone under the assumptions that (1) the water flow in the frozen zone could be described by the Darcy flow equation, (2) the generalized Clapeyron equation could be used to describe temperature-pressure relations and (3) ice pressure was equal to the overburden pressure behind the final ice lens. With decreases within a wider range of lower temperatures (?1 to ?10°C) than has ever been reported, the calculated hydraulic conductivities were found to decrease rapidly from 10^?11 to 10^?13 cm/s. It was also observed that the hydraulic conductivity did not depend greatly on the applied load.     

Wave propagation in transversely inhomogeneous dielectric waveguide

Guided mode propagation in inhomogeneous dielectric waveguides is calculated by a series expansion method which is particularly useful for analysing single-mode dielectric waveguides. As an example we estimate the error in the phase constant of waveguides whose dielectric constant profile is not necessarily near-parabolic.     

The behavior of incorporated impurities in tantalum anodic oxide films at the dielectric breakdown

Distribution profiles of incorporated impurities in anodic oxide films of tantalum were investigated before and after the dielectric breakdown of the film as a function of the depth of the film for incorporation of phosphorus, sulfur and chlorine. The in-depth distribution profiles of the incorporated impurities dramatically changed at the breakdown of the oxide films. However, the trend of the change was quite different among the incorporated impurities; chlorine is concentrated in the interior of the film, but phosphorus and especially sulfur showed tendencies to be swept into electrolytes. The ionization of the film seems to be responsible for these phenomena.     

Electromagnetic power absorption in cylindrical tissue models excited by a loop antenna

Approximate expressions are obtained for electromagnetic power absorption in cylindrical homogeneous models of biological tissues excited by a loop antenna located coaxially. The expressions are simple and can be computed even by a pocket calculator if a table of Bessel functions for complex arguments is available.     

Bending properties of hollow super-elastic Ti–Ni alloy wires and compound wires with other wires inserted

The purpose of this research was to investigate the possible orthodontic application of the hollow super-elastic Ti–Ni alloy wire, which was thought not only to deliver much lower and more continuous orthodontic force than conventional Ti–Ni wires, but also be able to be applied as a compound wire when combined with another wire. The examinations of bending properties were performed by the three-point bending test. The following results were obtained. 1. The hollow wire had lower load in the super-elastic range, smaller load-deflection rate and stress hysteresis in comparison with the conventional wire of the same diameter. 2. The load of the hollow wire was controllable by heat treatment. The stress hysteresis was further decreased by a two-step heat treatment. 3. The compound wire formed by inserting other types of wires into the hollow core exhibited changes in various bending properties such as increased load or load-deflection rate, according to the types and diameters of the inserted wire. The hollow wire delivers much lighter and more continuous orthodontic force, and, through heat treatment or deployment as a compound wire, it is possible to alter various bending properties. Therefore, this hollow wire was evaluated as a promising candidate for orthodontic application.     

Relationship between electron sensitivity and chemical structures of polymers as EB resists: Poly(lactam thioether) as new positive EB resists

Poly(lactam thioether) was synthesized from tetrahydro-1,4-thiazepine-5(4H)-one by a ring opening reaction under various conditions and was evaluated as positive electron beam(EB) resist. It was found that poly(lactam thioether) was easily decomposed by EB irradiation. The decomposition by EB exposure may be attributed to cleavage of C? S bonds in the polymer chains. The sensitivity of poly(lactam thioether) was influenced by prebake temperature, molecular weight, and developer, a high sensitivity of 5.3 × 10^?6 coulomb/cm² was observed with a good resolution of less than 1 μm. Poly(lactam thioether) showed a high sensitivity and a high resolution, and is suitable as a positive EB resist.     

Electron conduction in passive films on nickel

The electron conduction properties of the passive film on nickel in acid solution were studied by differential capacitance of nickel electrode in the passive condition, and by redox reactions of the Fe²⁺/Fe³⁺ and Q/H₂Q systems. A large capacitance value of the passive electrode, which is possibly comparable to that of the double layer, can be ascribed to the space charge capacitance in the passive film which is highly nonstoichiometric. The redox reaction currents of these systems may be sustained by tunnelling of charge carriers through the space charge layer in the passive film, if it can be accepted that the tunnel effect commences when the electric field strength in the space charge layer is of the order of 10⁶ V/cm. Consequently, the passive film can not be an insulator, at least in acid solutions.     

Stress transmission through Ti-Ni alloy, titanium and stainless steel in impact compression test

Impact stress transmission of Ti-Ni alloy was evaluated for biomedical stress shielding. Transformation temperatures of the alloy were investigated by means of DSC. An impact compression test was carried out with use of split-Hopkinson pressure-bar technique with cylindrical specimens of Ti-Ni alloy, titanium and stainless steel. As a result, the transmitted pulse through Ti-Ni alloy was considerably depressed as compared with those through titanium and stainless steel. The initial stress reduction was large through Ti-Ni alloy and titanium, but the stress reduction through Ti-Ni alloy was more continuous than titanium. The maximum value in the stress difference between incident and transmitted pulses through Ti-Ni alloy or titanium was higher than that through stainless steel, while the stress reduction in the maximum stress through Ti-Ni alloy was statistically larger than that through titanium or stainless steel. Ti-Ni alloy transmitted less impact stress than titanium or stainless steel, which suggested that the loading stress to adjacent tissues could be decreased with use of Ti-Ni alloy as a component material in an implant system. ©2000 Kluwer Academic Publishers