Theoretical investigation of ultrasmall polarization-insensitive 1/spl times/2 multimode interference waveguides based on sandwiched structures

A polarization-insensitive 1/spl times/2 multimode interference beam splitter based on sandwiched structures is proposed and investigated theoretically for the components of ultrasmall optical integrated circuits. Strong polarization dependencies arising in Si-wire waveguide systems are compensated by introducing sandwiched structures.     

Two-dimensionally quantized friction observed with two-dimensional frictional force microscope

Using a two-dimensional frictional force microscope, we studied the two-dimensional nature of the atomic scale friction between a Si₃N₄ sharp tip and a cleaved graphite surface, which is composed of only C atoms and is a good conductor. As a result, we observed the two-dimensionally quantized friction with the lattice periodicity of the graphite surface, similarly to mica, MoS₂ and NaF surfaces. Thus quantized friction occurs at material surfaces which are composed of not only some elements but also of a single element, and the quantized friction does not depend on the conductivity of the surface.     

GHTA welding phenomena of an aluminium alloy in a vacuum

The midair disintegration of the space shuttle 'Colombia', in which the total crew of 7 members was lost, occurred on 1^st February 2003. The circumstances of the crash shown on TV screens reaffirmed the public's view of the risks of space development and the importance of security. NASA has stopped any further space shuttle launches until the causes are fully investigated - a postponement of the completion of the International Space Station is inevitable. The operational life of the ISS is considered to be 10 years but it could be quite possible to prolong this if required for various reasons. Accordingly, it is highly likely that there will be requests for remodelling in order to achieve high levels of functional performance and to repair damage caused by debris impact and for other reasons. In order to meet these requirements it is essential to establish space welding technology.¹     

Pathology of chronic hepatitis C in children. Child Liver Study Group of Japan

Limited information is available regarding the histology of hepatitis C virus infection in children. The aim of this study was to determine the histological pattern of chronic hepatitis C (CHC) in children, and liver biopsy specimens from 109 pediatric patients with CHC were examined. Each biopsy specimen was evaluated based on a numerical scoring system for the stage of fibrosis (1-4), the grade of portal/periportal necroinflammation (0-4), the grade of lobular necroinflammation (0-4), and their sum (final grade). The histological lesions considered to be characteristic of chronic hepatitis were also evaluated. None of the children had liver cirrhosis, and 105 cases (97%) were stage 1 or 2. Only 4 children were stage 3. Two of these 4 cases showed hemosiderosis. A significant correlation was observed between the staging score and the final grade in the pediatric patients (r = .59; P < .0001). The histological characteristics of adult CHC, such as lymphoid aggregate, bile duct injury, and fatty changes, were also observed in the children. In conclusion, the majority of children with CHC presented with mild fibrosis, but a few showed CHC with lobular distortion and hemosiderosis. Frequent blood transfusion may aggravate hepatic lesions in pediatric CHC.     

A case of hypoxemic acute bronchiolitis presenting with diffuse nodular shadows caused by Mycoplasma pneumoniae

A fifty year-old female who had previously been well presented with a productive cough and a high fever. Her initial chest X-ray film showed no abnormal lung shadows. Despite partial improvement of the fever and the serum level of acute phase reactant (CRP) in response to intravenous administration of piperacillin, she complained of increasing severity of cough and dyspnea. Follow-up chest X-ray films taken five days after therapy with piperacillin showed diffuse nodular shadows in the mid-to-lower lung fields bilaterally. Chest CT scan disclosed diffuse miliary nodules at the lung periphery and thickening of bronchovascular markings. Chest auscultation revealed late inspiratory coarse crackles and expiratory wheezing, and the patient's arterial oxygen tension was 61 mmHg. Suspected of suffering from primary atypical pneumonia, she was started on therapy with intravenous minocyclin (200 mg/day), two days after treatment her symptoms began improving significantly. Anti-mycoplasma antibody was found to be x 1280, and cold hemoagglutinin x 1024, establishing the diagnosis of Mycoplasma pneumoniae infection. The patient's condition completely recovered following a one week treatment with minocyclin. We concluded that her respiratory infection was caused by piperacillin-sensitive mico-organism, and also Mycoplasma pneumoniae which brought about hypoxic acute bronchiolitis to the patient.     

Mitochondrial DNA polymerase from rat liver

A DNA-dependent DNA polymerase from rat liver mitochondria was partially purified and characterized. Mitochondrial DNA polymerase has been found to be quite different from other DNA-dependent DNA polymerases alpha and beta present in the rat liver in the following points: elution patterns in a DEAE-cellulose column chromatography, sedimentation coefficients determined by the glycerol gradient centrifugation in the presence of high salt, and sensitivities to N-ethylmaleimide, ethidium bromide and KCl.     

Establishment of anti-idiotype monoclonal antibodies to human anti lung cancer monoclonal antibody (4G12)

The object of this study is to establish anti-idiotype (anti-ID) monoclonal antibodies (MoAbs) against a human MoAb (4G12) that highly reacts with lung squamous cell carcinomas. Two murine anti-ID MoAbs (2H1 and 2B12) were established by hybridoma technology. They showed specific reactivity with 4G12 but not with 3H12 human MoAb, human IgM and human IgG. These two MoAbs demonstrated more than 90% of binding inhibition of 4G12 to lung squamous cell cancer cell line (PC10). Moreover, cross inhibition test showed that 2H1 and 2B12 detect different idiotypes of 4G12 each other. Furthermore, specific reactivity of anti 2H1 and anti 2B12 sera to PC10 were observed by cell binding ELISA. These two anti-ID MoAbs had internal image of the original antigen.     

Novel method for numerical analysis of electron trajectories in electrostatic fields of implicit functional forms

A novel method for calculating 2-dimensional electron trajectories is given, which is useful for the case when the electric fields are expressed by implicit functional forms which are not suited to a conventional electron-trajectory analysis. This method is applied to parallel-plate and parallel-cylinder deflection systems.