Radiation Tolerance Evaluation of the Ti/Au Bilayer TES Microcalorimeter

We have developed Ti/Au bilayer transition-edge sensor (TES) microcalorimeters for future X-ray astrophysical satellite missions such as DIOS. One possible concern on the space use of TES microcalorimeters is its radiation tolerance. We have evaluated the performance of a Ti/Au bilayer (30/40 nm thick) TES microcalorimeter with 1.5  \(\upmu \) m thick Au absorber, before and after irradiation of 150 MeV proton beam with a total dose of 10 krad, corresponding to 10 years in the low Earth orbit. No significant changes on transition temperature, sensitivity, normal resistance, and critical current were observed. The energy resolution for 5.9 keV X-rays was 5.6  \(\pm \)  0.3 eV (FWHM) after the irradiation, which was slightly worse than 5.1  \(\pm \)  0.3 eV before the irradiation. We consider that our TES has sufficient radiation tolerance in orbit.     

Preparation and properties of CuInS2 thin film prepared from electroplated precursor

Thin CuInS₂ films were prepared by sulfurization of Cu/In bi-layers. First, the precursor layer was electroplated onto the treated surface of Mo-coated glass. Observation of the cross-section prepared by focused ion beam (FIB) etching revealed that the void-free film was initially formed on the top surface of the precursor layer and continued to grow until the advancing front of the film reached the Mo layer. The nucleation of voids near the bottom of the CuInS₂ film followed. To determine whether the condition of the Cu/In alloy influences the CuInS₂ quality we investigated the Cu/In alloy state using FIB. We found that the annealed precursor of low Cu/In ratio (1.2) has several voids in the mid position in the layer compared with Cu-rich precursor (1.6). The cross-sectional view of the Cu-rich absorber layer is uniform compared with the low copper absorber layer. Thin film solar cells were fabricated using the CuInS₂ film (Cu/In ratio: 1.2) as an optical absorber layer. It was found that the optimization of a sulfurization period is important in order to improve the cell efficiency. We have not yet obtained good results with high Cu-rich absorber because of a blister problem. This blister was found before sulfurization. So, we are going to solve this blister problem before sulfurization.     

A novel tumor suppressor locus on chromosome 18q involved in the development of human lung cancer

The high incidence of loss of heterozygosity (LOH) on chromosome 18q in advanced non-small cell lung carcinomas indicates the presence of tumor suppressor gene(s) on this chromosome arm, which plays an important role in the acquisition of malignant phenotypes in lung cancers. In the present study, we examined 62 lung cancer specimens and 54 lung cancer cell lines for allelic imbalance at 11 microsatellite loci to define common regions of 18q deletions. Allelic imbalance of 18q was detected in 24 (55.8%) non-small cell lung carcinoma specimens and in 6 (31.6%) small cell lung carcinoma specimens, whereas a similar frequency of LOH was statistically inferred to occur in cell lines by analyzing marker homozygosity as an indirect measure of LOH. Five specimens and 11 cell lines showed partial or interstitial deletions of chromosome 18q, and 2 of them had homozygous deletions at the 18q21.1 region. A commonly deleted region was assigned between the D18S46 and y953G12R loci. The size of this region is less than 1 Mb, and the coding exons of three candidate tumor suppressor genes, Smad2, Smad4, and DCC, were mapped outside the region. This result suggests that the common region harbors a novel tumor suppressor gene involved in the progression of lung cancer.     

Cloning and nucleotide sequence of fosfomycin biosynthetic genes of Streptomyces wedmorensis

The biosynthetic pathway for production of the antibiotic fosfomycin by Streptomyces wedmorensis consists of four steps including the formation of a C-P bond and an epoxide. Fosfomycin production genes were cloned from genomic DNA using S. wedmorensis mutants blocked at different steps of the biosynthetic pathway. Four genes corresponding to each of the biosynthetic steps were found to be clustered in a DNA fragment of about 5 kb. Nucleotide sequencing of a large fragment revealed the presence of ten open reading frames, including the four biosynthetic genes and six genes with unknown functions.     

Observation of a child with multiple submerged primary teeth

The authors presented a case report of a seven-year-old male with eight submerged primary molars and a primary lateral incisor. Two major treatment modalities, tooth extraction and observation, were reported. In this case we applied the two alternative modalities and observed the patient for five years. The permanent successors were in the process of almost normal eruption after the extraction of the submerged primary teeth; no eruption and more severe submerging were observed, however, in the permanent successors of the submerged primary teeth that were not extracted. These results suggest that submerged or impacted primary teeth should be extracted immediately when they are moderately or severely submerged.     

A case of spontaneous rupture of renal cell carcinoma

Spontaneous rupture of the kidney is uncommon. We report a case of spontaneous rupture of the kidney due to a renal cell carcinoma. A 53-year-old man presented with right renal tumor. Computed tomography demonstrated a 70 mm right renal tumor which involved the entire upper pole of the kidney and extended into the renal vein. A few days later, the patient had sudden severe right flank pain. Computed tomography of the abdomen revealed a large perirenal hematoma of the right kidney. Angiography demonstrated no vascular abnormality. Nephrectomy was performed. The histological examination showed rupture of a renal cell carcinoma in the right kidney.     

Hybrid nanocomposite based on NbWO6 nanosheets and polyaniline

Synthesis and characterization of the hybrid nanocomposite based on polyaniline and NbWO₆ nanosheets is reported here. Formation of the nanocomposite is reflected by the increase of interlayer distance of NbWO₆ nanosheets and the XRD pattern depicts the formation of NbWO₆/polyaniline nanostructure with interlayer separations of 1.6 nm and 0.9 nm which is consistent with a bilayer and a monolayer of polyaniline molecules within the gallery of nanosheets. Transmission electron micrographs, infrared spectra and thermograms support the formation of the hybrid nanocomposite. Electrochemical investigations on the nanocomposite reveal the presence of polyaniline and the data is compared also with those of polyaniline and host.     

Structural shock tests of prototype FBR “MONJU” scale models

This paper presents some results of experiments which simulate the structural dynamic response of a LMFBR primary coolant boundary to a hypothetical core disruptive accident (HCDA) based on scale models and high explosives. It was noted that high explosives are no longer a good simulant of the HCDA. However, the main purpose of the program, which included this experiment, is not to experimentally predict the dynamic response of the reactor structure at the HCDA, but to validate computer codes, which describe the pressure wave propagation and damage process in the reactor structures, using data obtained from these model experiments. The experiments were undertaken using many 1/15 scale simple models of the reactor vessels and internal structures, as well as 1/15 and 1/7.5 scale complex models of the interim design of prototype LMFBR ‘MONJU’. Simple model experiments involved a series of shock tests using pentolite to investigate the configuration effects of the vessel restraining section, the dipped-plate effect and the core barrel effect, respectively.