Pulmonary infection with Mycobacterium avium-intracellulare leads to air trapping distal to the small airways

To clarify the structure and function of the airways in Mycobacterium avium-intracellulare (MAI) infection, we performed pulmonary function tests and high-resolution computed tomography (HRCT) of the thorax in female patients 61 +/- 9 yr of age (n = 12) with pulmonary MAI infection without predisposing lung disease and compared their data with those of normal female volunteers 54 +/- 8 yr of age (n = 9). We calculated the E/I ratio, i.e., the average ratio of HRCT number at full expiration to that at full inspiration, as an index for the evaluation of air trapping distal to the small airways. Patients showed significant increases in residual volume and slope of phase III (DeltaN2) of the single-breath nitrogen test, and significant decreases in flow at 50 and 25% of FVC, suggesting hyperinflation and obstruction of the small airways. HRCT of patients revealed the small nodules and ectasis of bronchioles and small bronchi located mainly in segments (S) S2, S3, S4, and S5. The E/I ratio was significantly elevated in patients, and especially higher in the upper lung field than in the lower lung field, suggesting air trapping distal to the small airways. The difference of E/I ratio between the upper and lower field is probably related to the segmental distribution of CT abnormalities. These findings suggest that MAI infection can lead to air trapping distal to the small airways.     

Surgical management for lymph node recurrence of resected fibrolamellar carcinoma of the liver: a case report

Fibrolamellar carcinoma of the liver (FLC), which is very rare in Japan, is reported to be frequently accompanied by lymph node metastasis in Europe and the United States. We describe a 22-year-old man with recurrent FLC in the lymph nodes after undergoing partial hepatectomy. He underwent a second operation for removal of recurrent lymph node tumors in the mediastinum and abdominal cavity one year after initial surgery. However, a third operation became necessary seven months later, because of recurrence in a lymph node in the abdominal cavity. We discuss the management of lymph node metastasis from FLC.     

Adsorption and photocatalytic decomposition of methylene blue on mesoporous metallosilicates

Mesoporous silica and mesoporous metallosilicates with Al, Ti and Fe as foreign metal species were successfully synthesized by the rapid room temperature method. Mesoporous metallosilicates with low contents of foreign metals possessed high surface area (S_a), large mesopore volume (V_mp) and highly ordered hexagonal mesoporous structure. Increases in foreign metal contents caused disordering the mesoporous structures and lowering the S_a and V_mp values. Bleaching of aqueous methylene blue (MB) by mesoporous silica and metallosilicates was investigated. Mesoporous aluminosilicate and ferrosilicate with cation-exchangeable ability showed the excellent property for the adsorption of MB of cationic dye, while mesoporous ferrosilicate and titanosilicate which absorbed UV lights catalyzed the photocatalytic decomposition of MB under UV-illumination.     

Photoelectrochemical observations on chlorophyll- carotene interactions in a lipid bilayer film

Photoelectrochemical investigations were undertaken on energy transfer and other interactions between chlorophyll-a (Chl-a) and β-carotene (Car) in lipid monolayers. A heterobilayer composed of a Chl-a-lecithin monolayer and a Car- lecithin monolayer was prepared on an SnO₂ semiconductor electrode by Langmuir-Blodgett techniques. When the bilayer-coated electrode was irradiated in an aqueous electrolyte, anodic photocurrents due to the sensitizations by Chl-a and Car respectively were observed. The photocurrent efficiency (ratio of photons to electrons) was much for Car (about 10^-3) than for Chl-a (about 10^-1). This large difference permits a quantitative estimation of the energy transfer from Car to Chl-a, based on the concept that the energy transfer results in an increase in the Car- induced sensitized photocurrent. The effect of added Chl-a on the Car photocurrent was measured for heterobilayers with various Chl-a-to-Car molar ratios. The experimental results, as well as theoretical calculations, showed that the Car-to- Chl-a energy transfer is inefficient. The effect of Car on the Chl-a-sensitized photocurrent was also studied with the same bilayer system. The effect was shown to be complex depending on the Car content. A lowering of the Chl-a photocurrent occurred at high Car contents, which is considered to reflect the quenching of the Chl-a excited triplet by Car. The usefulness of the present photoelectrochemical approach for the study of energy transfer between the photosynthetic pigments is demonstrated.     

Fracture toughness of Zr-2.5 wt% Nb pressure tubes

Measurements of fracture toughness of HT Zr-2.5 wt% Nb pressure tubes have been made by studying internally pressurizing (burst) test specimens and small bending test specimens. These tests were conducted from a viewpoint of the effects of hydrogen content, hydride orientation, temperature and crack configuration on the fracture thoughness K_c. Results of the experiments showed that K_c decreased with increasing hydrogen content, but is little affecting by hydrogen content at reactor operating temperature. The value of K_c can be quantitatively evaluated by RHC defined by radial hydride content (RHC) perpendicular to the tensile stress.     

Development of a simple method to evaluate medical staff radiation dose and its application to a software system supporting PET facility operation

In recent years, positron-emitting labelled radiopharmaceuticals have come to be used in conjunction with positron emission tomography (PET) in various clinical diagnoses. Radiation exposure of the medical staff is a key issue in the design of PET facilities intended to handle large numbers of persons for PET diagnosis. As a first step, the radiation dose to individuals who received radiopharmaceuticals was calculated using a mathematical phantom model and the EGS4 electromagnetic cascade Monte Carlo code and MCNP Monte Carlo code. Dose rate behind a lead shield was also calculated for various lead thicknesses. The radiation dose distribution around a syringe containing a positron emitter was calculated. The calculated dose distributions were fitted to polynomial equations. These calculations were evaluated against measurements. The second step was to evaluate medical staff dose at a specified time by superimposing dose distribution from each person who received radioisotopes taking into account radioactive decay. In this way, we developed software to support PET facility operation, namely, planning, prediction, control of medical staff dose and facility operation. This system was also designed to schedule daily radiopharmaceuticals production and to manage radioactive wastes by taking decay time into account.     

Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperature. II. Optical strain of remaining stress type

Previously it was found that casting could be carried out efficiently without strain formation by radiation-induced polymerization of glass-forming monomers. Two types of strain were observed in casting: thermal stream type, which was studied previously, and remained stress type. In this report, the effect of various factors on the formation of remaining stress-type strain in radiation-induced casting polymerization was studied. It was found that the molecular weight of prepolymer did not affect strain formation, while prepolymer concentration and viscosity of the system had a serious influence on strain formation. It could be deduced that this type of strain formed as a result of remaining inner stress due to poor relaxation of the shrinking stress. It was realized that less volume shrinkage of glass-forming monomers accompanying casting polymerization reduced the strain formation of this type in radiation-induced casting polymerization at low temperatures.     

Threshold voltage of ion implanted GaAs MESFET

Threshold voltages for ion implanted GaAs MESFETs are measured and shown to have good coincidence with calculated results. The effect of implantation energy on threshold voltage is discussed. The optimum implantation energy is about 45 ~ 60 keV.