Measurement of the whole-body 137Cs in residents around the Chernobyl nuclear power plant

To understand the current situation of internal radiation exposure in the population around the Chernobyl Nuclear Power Plant (CNPP), we examined the 137Cs body burden in six residents of Belarus, Ukraine and Russia in 2002 and 2004 using the whole-body counter (WBC) at Nagasaki University (Japan). The data were compared with those of our previous study performed in 1993-1994 using the same method. In 2002 and 2004, peaks of 137Cs were detected in two residents from Gomel, which was heavily contaminated by the CNPP accident, one from Minsk (Belarus) and one from Kiev (Ukraine), but another resident from Minsk showed no 137Cs peaks. The results of the present study suggests that residents around the CNPP are still exposed to chronic 137Cs internal irradiation, probably due to the daily consumption of contaminated domestic foods, but the risk of any disease by the irradiation is quite low. Long-term follow-up of WBC around the CNPP is useful and may contribute to radiation safety regulation together with a reduction of unnecessary radiophobia for the residents.     

In vivo scattering measurement of biological tissue by the use of a pyroelectric polymer transducer

We propose a new method, to our knowledge, for noninvasive scattering measurements of tissues by the use of a pyroelectric polymer transducer, poly(vinylidene fluoride trifluoroethylene) film. In this method, samples are irradiated with nanosecond, low-energy light pulses delivered from an optical fiber, and the pyroelectric signal induced by the diffuse reflectance is measured with a transducer. The signal is then converted into diffuse reflectance by use of a calibration factor. The validity of this method was confirmed by our measuring the scattering coefficient of a white acrylic resin within an accuracy of +/- 15%. We attempted to apply this method to the estimation of scattering coefficients of normal and burned skins in rats in vivo.     

Molecular characterization of morphologically typical human calicivirus Sapporo

Human calicivirus Sapporo (SV) has typical calicivirus morphology and causes acute gastroenteritis in children. The nucleotide sequence of 3.2 kb of the 3' end of SV was determined from a cloned cDNA. The 3' end of the SV genome is predicted to encode the RNA-dependent RNA polymerase region, the capsid protein and two small open reading frames. The nonstructural and capsid protein coding sequences in the SV genome are fused in a single open reading frame. The organization of these proteins in the SV sequence is similar to that of rabbit hemorrhagic disease virus and the recently described Manchester virus, and distinct from the genome organization of the prototype human calicivirus, Norwalk virus, that lacks typical calicivirus morphology and has been described as a small round structured virus (SRSV). Sequence analysis of the predicted capsid region showed that the SV capsid is longer by approximately 30 amino acids than the capsid of any of the SRSVs, and multiple sequence alignments showed that these additional amino acids are located in the variable region of the capsid protein. Expression of the capsid protein of SV in insect cells resulted in the self-assembly of virus-like particles that have a morphology similar to that of the native virus. This result shows that calicivirus morphology is determined by the primary sequence of the capsid protein.     

Chlorine isotope fractionation during reductive dechlorination of chlorinated ethenes by anaerobic bacteria

Chlorine isotope fractionation during reductive dechlorination of trichloroethene (TCE) and tetrachloroethene (PCE) to cis-1,2-dichloroethene (cDCE) by anaerobic bacteria was investigated. The changes in the 37Cl/35Cl ratio observed during the one-step reaction (TCE to cDCE) can be explained by the regioselective elimination of chlorine accompanied by the Rayleigh fractionation. The fractionation factors (alpha) of the TCE dechlorination by three kinds of anaerobic cultures were approximately 0.994-0.995 at 30 degrees C. The enrichment of 37Cl in the organic chlorine during the two-step reaction (PCE to cDCE) can be explained by the random elimination of one chlorine atom in the PCE molecule followed by the regioselective elimination of one chlorine atom in the TCE molecule. The fractionation factors for the first step of the PCE dechlorination with three kinds of anaerobic cultures were estimated to be 0.987-0.991 at 30 degrees C using a mathematical model. Isotope fractionation during the first step would be the primary factor for the chlorine isotope fractionation during the PCE dechorination to cDCE. The developed models can be utilized to evaluate the fractionation factors of regioselective and multistep reactions.     

Sorbistin, a new aminoglycoside antibiotic complex of bacterial origin. III. Structure determination

The structures of sorbistins A1, A2, B, C and D have been determined including stereo-chemistry. Sorbistins A1, A2 and B are composed of a 4-acyl-amino-4-deoxy-D-glucose and 1,4-diamino-1,4-dideoxy-D-sorbitol, the latter compound being hitherto undescribed in literature. Sorbistins C and D have the same aglycone of 1,4-diamino-1,4-dideoxy-D-sorbitol, which is linked with D-glucose and 4-amino-4-deoxy-D-glucose, respectively, through a glycosidic bond.     

Studies on relationship between activity and electron density on carbonyl oxygen in sex pheromone mimics of the American cockroach,part XI

From the relationship between structures of the 2-substituents of verbanyl analogs and their sex pheromone activities to the American cockroach, electron density of the carbonyl oxygen atom in the substituent, as estimated by the [¹⁷O]NMR chemical shift, was estimated to be an important factor which influenced the activity, in addition to length of the substituent and the position of the carbonyl group. (+)-Verbanyl methylcarbonate (XX), possessing the highest electron density on the carbonyl oxygen atom, showed the strongest activity among the analogs.For Part X, see Manabe et al., 1983. J. Chem. Ecol. 9:533–549.     

Effects of End Groups on the Tribochemical Reactions of Lubricants at Head-Disk Interface

Mass spectrometry was used to monitor in-situ gaseous species that were generated at the head-disk interface (HDI) in a high vacuum. It was found that the end groups of the lubricants significantly affected the wear durability at the HDI; piperonyl (–CH₂-phe = (O)₂ = CH₂) terminated Fomblin AM3001 lubricant exhibited longer life than hydroxyl (–OH) terminated Fomblin ZDOL lubricant. The continuous removal of the lubricants resulted in a continuously increasing friction coefficient. Further, the characteristics of tribochemical reactions of the lubricants (Fomblin Z series) with different end groups was investigated in details using Time-of-Flight Secondary Ion Mass Spectroscopy (TOF-SIMS) just after the sliding tests. It was found that the decomposition of the end groups was more significant than that of the backbone. The lubricants terminated with the following groups showed the following order of increasing decomposition: –CH₂O-CH₂-phe = (O)₂ = CH₂ (AM3001), –CH₂OH (ZDOL) < –CH₂OCH₂CH(OH)CH₂OH (Z Tetraol) < –CH₂(OCH₂CH₂)_nOH (ZDOL-TX), –COOH (Z Diac). The decomposition of the lubricants appeared to start from the end groups.     

Development of a 1 MV field-emission transmission electron microscope

We developed a 1 MV field-emission transmission electron microscope. This paper reports details and specifications of the instrument. The microscope was designed to obtain a bright and coherent electron beam by using the field emission gun equipped with a pre-accelerating magnetic lens and the high-voltage power supply with high stability (0.5 ppm min(-1)). Using this microscope, the brightness of 1.8 x 10(10) A cm(-2) sr(-1) and the lattice resolution of 49.8 pm were attained.     

A case study: a network system for knowledge amplification in theproduct development process

Future product development is expected to evolve from the current stage, where the final commercial product is most important aspect of production, to the stage where the knowledge required for product development is of greatest significance. This study aims to construct an engineering management information system applicable to this new age of knowledge. Approaches are formulated from the standpoint of knowledge amplification in the engineering process. First, Sony's current product development process which is based on event management, product planning, and the subsequent design processes are analyzed to clarify the sequence of knowledge amplification. Then the sequence of knowledge amplification of individual engineers and that of the organization groups are analyzed, and a new network system supporting the product development process is proposed