An image processing system using Image Signal Multiprocessors (ISMPs)

This paper describes an image processing system using Image Signal Multiprocessors (ISMPs) adapted to gray-level image preprocessing for image analysis and image enhancement. It is composed of four ISMPs, five 1H-delay-lines, two 512×512×8-bit frame memories, a video timing controller (VTC), two 256-word ×8-bit ×8-table Look Up Tables (LUTs) and 80 nsec/sampling A/D and D/A converters. This multiprocessor system performs convolution operations such as spatial filters, contrast enhancement, and binarization for gray-level images, thinning, thickening, pattern matching etc. for binary images, and image quality improvement for moving images such as T.V. images. Otherwise, it performs feature extraction operations such as area calculations, fillet coordination, and moment calculations for objective image data. Moreover, this system is capable of applying color image processing by using a multiboard system.     

Direct contact melting of porous material

The direct contact melting of a porous material is investigated experimentally and analytically. The phase change material (PCM) is made of fine ice particles of a nearly uniform diameter, which is changed as a parameter. In the analysis, two models are proposed. One is calculated as the direct contact melting of a monolithic sample and another is treated as an assembly of the direct contact melting of the individual particles. As a result, it was found that the heat flux increased with the diameter, due to increase of permeability in a case of small diameter. But, in a case of large diameter, the heat flux decreased as the particle diameter increased because the direct contact melting occurred independently for the individual particles.     

Simulation study of eutrophication in Hiroshima Bay: Simulation of particulate and dissolved organic matter using cyclic transformation of carbon

A phytoplankton model, which includes a carbon cycle combined with a constant current obtained by the computation of tidal currents, was applied to the coastal region (Hiroshima Bay, Japan). The transformation rate constants for the carbon cycle were experimentally evaluated.The seasonal variations of particulate and dissolved organic matter by the simulation model were reasonably consistent with the field data. Carbon concentration increased by primary production in the upper layer was approx. 10 times that augmented by loading of carbon from land at the shore in summer. Sinking plays an important role in the elimination of particulate organic matter. On the other hand, horizontal advection and turbulent diffusion are important factors for the diminution of dissolved organic matter.     

Simplified quantitative assay system for measuring activities of drugs against intracellular Legionella pneumophila

We developed a new simple assay for the quantitation of the activities of drugs against intracellular Legionella pneumophila. The cells of a murine macrophage-like cell line (J774.1 cells) allowed the intracellular growth and replication of the bacteria, which ultimately resulted in cell death. The infected J774.1 cell monolayers in 96-well microplates were first treated with antibiotics and were further cultured for 72 h. The number of viable J774.1 cells in each well was quantified by a colorimetric assay with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and an enzyme-linked immunosorbent assay reader. The number of growing bacteria in each well was also determined by counting the numbers of CFU on buffered charcoal yeast extract-alpha agar plates. Viable J774.1 cell counts, determined by the colorimetric assay, were inversely proportional to the number of intracellular replicating bacteria. The minimum extracellular concentrations (MIECs) of 24 antibiotics causing inhibition of intracellular growth of L. pneumophila were determined by the colorimetric assay system. The MIECs of beta-lactams and aminoglycosides were markedly higher than the MICs in buffered yeast extract-alpha broth. The MIECs of macrolides, fluoroquinolones, rifampin, and minocycline were similar to the respective MICs. According to their intracellular activities, clarithromycin and sparfloxacin were the most potent among the macrolides or fluoroquinolones tested in this study. Our results indicated that the MTT assay system allows comparative and quantitative evaluations of the intracellular activities of antibiotics and efficient processing of a large number of samples.     

The elimination of hepatitis B virus infection: changing seroepidemiology of hepatitis A and B virus infection in Okinawa, Japan over a 26-year period

Serial changes in hepatitis A virus (HAV) and B virus (HBV) markers were determined from 1970 to 1996 in healthy Japanese residents of a rural area of Okinawa, Japan. All 190 serum samples taken in 1970, 791 in 1980, 708 in 1988, and 523 in 1996 from residents 0 to more than 60 years of age were tested for antibody to HAV (anti-HAV), antibody to hepatitis B core antigen (anti-HBc), and hepatitis B surface antigen (HBsAg). The age-adjusted prevalences of anti-HAV and anti-HBc decreased significantly from 83.9% and 74.9%, respectively, in 1970 to 39.7% and 36.6%, respectively, in 1996. In residents < or = 29 years of age, the prevalences of anti-HAV and anti-HBc decreased significantly from 65.3% and 83.8%, respectively, in 1970 to 0.7% and 8.2%, respectively, in 1996. The age-adjusted HBsAg prevalence decreased significantly from 8.2% in 1980 to 4.1% in 1988. These results indicate that exposure to HAV and HBV infections among Okinawa residents less than 29 years of age is decreasing, probably because of improvements in socioeconomic conditions since 1970. Infection with HBV may be eliminated there in the near future.     

Shear bond strength of amalgam adhesives to dentin

Recent studies have suggested that failure of pentamidine prophylaxis against Pneumocystis carinii pneumonia (PCP) may be due to reduced deposition of pentamidine in the upper lobes. In this study, we performed bronchoalveolar lavage from the apical segment of the upper lobe and the middle lobe in 51 HIV-positive patients, all of whom were receiving prophylaxis with aerosolized pentamidine, who had presented with acute respiratory symptoms. Lavage fluid from each lobe was assayed for pentamidine using high-performance liquid chromatography (HPLC). The number of clusters of P carinii were counted after staining with a Wright-Giemsa stain. The patients were subclassified as PCP-positive (32 patients) and PCP-negative (19 patients) on the basis of the presence/absence of P carinii clusters in their BAL fluid. The concentration of pentamidine in the upper lobe compared with the middle lobe was no different (using paired Student's t tests) for either PCP-positive patients or PCP-negative patients. In comparing the positive with the negative subjects, using unpaired Student's t test, there was no difference in the concentration of pentamidine in the upper lobe or the middle lobe. For PCP-positive patients, the numbers of P carinii clusters were on average higher in the upper lobes (mean +/- SD: upper = 14.9 +/- 16.6, middle 7.5 +/- 10.8, p = 0.013, paired Student's t test), but there was no correlation between lobar P carinii cluster counts and pentamidine levels. We conclude that the absence of a relationship between cluster count and pentamidine level, the similarity in regional pentamidine levels between upper and middle lobes, as well as the similarity in pentamidine levels between the PCP-positive and PCP-negative groups indicate that the regional dose of pentamidine is not the determining factor as to whether aerosolized pentamidine prophylaxis will succeed or fail.     

Wheel/rail contact dynamics in turnout negotiations with combined nodal and non-conformal contact approach

In railroad turnouts, geometries of tongue and crossing rails are very complex and their shapes are changing along the track. Therefore, wheels are subjected to not only tread and flange contacts, but also the back-of-flange and top-of-flange contacts in the case of spring switches of tram vehicles. For this reason, one needs to deal with significant jumps in contact points for solving wheel/rail contact problems in turnout, and an accurate prediction of jumps in contact points is one of the most important issues that need to be carefully handled in the dynamic simulation of vehicle/turnout interactions. In this investigation, a numerical procedure that can be used for solving such a complex wheel/rail contact problem in turnout is proposed. In particular, a combined nodal and non-conformal contact approach is developed such that significant jumps in contact points are detected using the nodal search, while the exact location of contact point is then determined with continuous surface parameterizations using non-conformal contact equations. With this combined nodal and non-conformal contact approach for the contact geometry analysis of vehicle/turnout interactions, multiple look-up contact tables can be generated in an efficient way without losing accuracy. Since detailed contact search is performed off-line to obtain look-up contact tables, significant changes in contact points in turnout can be efficiently predicted on-line with tabular data to be interpolated in a standard way. Several numerical examples are presented in order to demonstrate the use of the numerical procedure developed in this investigation.     

Preparation and characterization of porous and electrically conducting carbon-clay composites

Porous and electrically conducting carbon-clay composites were prepared by firing mixtures of carbon powder (0 to 20 wt%) and clay minerals. They showed porosity of 50 to 65% and had high mechanical strength (compressive strength = 130 to 400 kg cm^–2) as well as high resistance against thermal oxidation in air. Their electrical conductivity, , increased with increasing carbon content levelling off at about 20 wt% of carbon content to give a value of about 2 S cm^–1. Formation of carbon chains is considered to be responsible for the electrical conduction in the composite, and a model to correlate the electrical conductivity with the carbon content has been proposed by modifying a model previously proposed by Scarisbrick.     

Preparation and photoconduction of rapidly quenched films in the Bi2O3-TiO2 system

The rapidly quenched films in the Bi₂O₃-TiO₂ system (0 to 60% TiO₂) were prepared using a twin-roller type apparatus. The films precipitated Bi₂O₃ solid solutions of different types in the composition ranges, with TiO₂ contents of 0 to 5, 7.5 to 10 and 12.5 to 40%, respectively. The first solid solution had a tetragonal structure of -form. The second, though also crystallized in the tetragonal structure, adopted a disordered modification of the -form. The third solid solution was -form (defect fluorite structure). The formation of amorphous phase commenced in the composition with 30% TiO₂, and the films became completely amorphous beyond 50% TiO₂. The quenched films showed a certain instability to decompose or transform into the different phase assemblage by annealing at higher temperatures (about 400 to 500° C, except 260° C for the pure Bi₂O₃ film). The quenched films were also characterized by a high photoconductivity. The photoconduction mechanism was suggested to be associated with a structural imperfection of Bi₂O₃ accompanied by a certain amount of pentavalent bismuth ion.     

Crystallization of potassium titanate from the amorphous phase

By using amorphous potassium titanates as the starting materials, a sintered body of K₂Ti₄O₉ or K₂Ti₆O₁₃ with porous and fibrous textures was prepared. K₂Ti₂O₅ and a new phase, K₆Ti₄O₁₁ were synthesized by the thermal reaction of KNO₃ with TiO₂ at 1000° C for 10 to 20 h. On leaching in water to expel excess of potassium ions, both phases became amorphous. After mixing and moulding these amorphous materials in the desired proportion, a sintered body containing fibrous crystals of K₂Ti₄O₉ was readily fabricated by heating at 1000° C for 12 h. When 5 wt % B₂O₃ was added to the amorphous phases, single phase K₂Ti₆O₁₃, with a fibrous texture grew well on heating at 1000° C for 12 h. Addition of PVA polymer to the amorphous phases was responsible for controlling the porosity of the sintered body, e.g. about 52% theoretical density at 20 wt% PVA polymer. The optimum conditions for preparing the amorphous phases were systematically examined and the effect of the chemical reaction environments, such as different crucible materials on the calcination of KNO₃ and TiO₂ were also discussed.