Various scintillation devices are used in many countries and wide scientific fields. Key elements that determine the performance of a scintillation device are the number of photons emitted per incident radiation event and the emission of easy-to-measure blue photons. It is generally known that only materials with very complex compositions perform well as scintillators. However, we demonstrated that the scintillation performance of a newly developed plastic such as 100 percent pure polyethylene naphthalate exceeds that of conventional organic scintillators. By measuring the light output spectra and emission spectra of several samples, we revealed that the plastic emits a high number of photons per incident radiation event (∼ 10500 photons/MeV), and, surprisingly, deep-blue photons (425 nm). Even though the plastic has a simple composition, it could replace the expensive organic scintillators that have been used in many applications.

The complete nucleotide sequence of pRGO1, a cryptic plasmid from Propionibacterium acidipropionici E214, was determined. pRGO1 is 6,868 bp long, and its G؉C content is 65.0%. Frame analysis of the sequence revealed six open reading frames, which were designated Orf1 to Orf6. The deduced amino acid sequences of Orf1 and Orf2 showed extensive similarities to an initiator of plasmid replication, the Rep protein, of various plasmids of gram-positive bacteria. The amino acid sequence of the putative translation product of orf3 exhibited a high degree of similarity to the amino acid sequences of DNA invertase in several bacteria. For the putative translation products of orf4, orf5, and orf6, on the other hand, no homologous sequences were found. The function of these open reading frames was studied by deletion analysis. A shuttle vector, pPK705, was constructed for shuttling between Escherichia coli and a Propionibacterium strain containing orf1 (repA), orf2 (repB), orf5, and orf6 from pRGO1, pUC18, and the hygromycin B-resistant gene as a drug marker. Shuttle vector pPK705 successfully transformed Propionibacterium freudenreichii subsp. shermanii IFO12426 by electroporation at an efficiency of 8 ؋ 10 6 CFU/g of DNA under optimized conditions. Transformation of various species of propionibacteria with pPK705 was also performed at efficiencies of about 10 4 to 10 7 CFU/g of DNA. The vector was stably maintained in strains of P. freudenreichii subsp. shermanii, P. freudenreichii, P. pentosaceum, and P. freudenreichii subsp. freudenreichii grown under nonselective conditions. Successful manipulation of a host-vector system in propionibacteria should facilitate genetic studies and lead to creation of genes that are useful industrially.Propionibacteria, which have a wide range of probiotic activity, are used in making dairy foods, such as cheese, for the production of vitamin B 12 , tetrapyrrole compounds, and propionic acid (8,15,21), in bread baking, as starters for ensilage, and in some pharmaceutical preparations (35). To elucidate the biosynthetic pathways of vitamin B 12 and siroheme in Propionibacterium, we previously identified several genes coding for the enzymes involved in production of tetrapyrrole derivatives (hemYHBXRL) (11,12) and vitamin B 12 (cobA, cbiO) (30).Development of genetic manipulation in propionibacteria has progressed slowly due to a lack of detailed information on the genetics of the bacteria and a lack of an appropriate plasmid that can serve as a possible transformation vector. A number of plasmids from Propionibacterium acidipropionici, P. freudenreichii, and P. jensenii, ranging in size from 4.4 to more than 119 MDa, have been described (19,24). However, neither analysis of a plasmid DNA sequence nor construction of a vector for propionibacteria has been reported. To establish a versatile vector system to facilitate genetic analysis and to allow the transfer of a gene of interest, we investigated the development of a host-vector system in propionibacteria.We succeeded in determining the co...

Abstract-A Compton camera is the most promising approach for gamma-ray detection in the energy region from several hundred keV to MeV, especially for application in high energy astrophysics. In order to obtain good angular resolution, semiconductor detectors such as silicon, germanium and cadmium telluride(CdTe) have several advantages over scintillation detectors, which have been used so far. Based on the recent advances of high resolution CdTe and silicon imaging detectors, we are working on a Si/CdTe Compton camera. We have developed 64-pixel CdTe detectors with a pixel size of 2 mm×2 mm and double-sided Si strip detectors(DSSDs) with a position resolution of 800µm. As a prototype Si/CdTe Compton camera, we use a DSSD as a scatterer and two CdTe pixel detectors as an absorber. In order to verify its performance, we irradiate the camera with 100% linearly polarised 170 keV γ-rays and demonstrate the system works properly as a Compton camera. The resolution of the reconstructed scattering angle is 22• (FWHM). Measurement of polarization is also reported. The polarimetric modulation factor is obtained to be 43%, which is consistent with the prediction of Monte Carlo simulations.

Short-stretch bandages can be expected to have more pronounced benefits for augmenting muscle pump than long-stretch bandages and short-stretch stockings.

The importance of measuring interface pressure and stiffness to characterize the elastic properties of materials has been stressed with regard to elastic stockings and elastic bandages. The objective of this study was to compare the pressure profiles of nine different elastic stockings and to quantify the effects of posture changes and exercise on compression. Using a pressure transducer (Air Pack Type Analyzer), the interface pressure associated with nine different elastic stockings was measured at level B1 during supine resting, standing, and exercise. The elastic stockings examined could be divided into two categories according to extensibility: short stretch (< 105% extensibility) and long stretch (> 105% extensibility). Short-stretch stockings include thick round-knitted stockings, firm round-knitted stockings, and flat-knitted stockings. Short-stretch stockings showed a higher peak working pressure and a larger pressure amplitude during exercise than long-stretch stockings. Short-stretch stockings can be expected to have more pronounced benefits for augmenting muscle pumping in the same way as short-stretch bandages. In selecting suitable elastic stockings for patients, the stiffness should be taken into account in addition to interface pressure.