Preparation of cell-enclosing microcapsules through photopolymerization of methacrylated alginate solution triggered by irradiation with visible light

A photopolymerizable, methacrylated alginate was synthesized by conjugating methacryloyl groups to the side chains of alginate. Cell-enclosing microcapsules were subsequently prepared by the photopolymerization of cell-suspending methacrylated alginate droplets triggered by irradiation with visible light. Cells enclosed by this method remained alive in the microcapsules for at least 2 weeks.     

Mathematical models assuming selective recruitment fitted to data for driver mortality and seat belt use in Japan

Previous research has indicated that unbelted drivers are at higher risk of involvement in fatal crashes than belted drivers, suggesting selective recruitment that high-risk drivers are unlikely to become belt users. However, how the risk of involvement in fatal crashes among unbelted drivers varies according to the level of seat belt use among general drivers has yet to be clearly quantified. We, therefore, developed mathematical models describing the risk of fatal crashes in relation to seat belt use among the general public, and explored how these models fitted to changes in driver mortality and changes in observed seat belt use using Japanese data. Mortality data between 1979 and 1994 were obtained from vital statistics, and mortality data in the daytime and nighttime between 1980 and 2001 and belt use data between 1979 and 2001 were obtained from the National Police Agency. Regardless of the data set analyzed, exponential models, assuming that high-risk drivers would gradually become belt users in order of increasing risk as seat belt use among general motorists reached high levels, showed the best fit. Our models provide an insight into behavioral changes among high-risk drivers and support the selective recruitment hypothesis.     

Enhancement of MALDI-MS spectra of C-terminal peptides by the modification of proteins via an active ester generated in situ from an oxazolone

For selective C-terminal derivatization of peptides and proteins, we have devised a method for activating the C-terminal carboxyl group by extending the oxazolone chemistry. A mixture of formic acid and acetic anhydride was found to be effective for the formation of an oxazolone, which was converted to an active ester in situ in the presence of a phenol or an N-hydroxide. In particular, the resulting active ester with pentafluorophenol facilitated the subsequent reaction with an amine and the hydrazine derivative to yield the C-terminal amide and hydrazide, respectively. The peptides thus coupled with arginine methyl ester or 2-hydrazino-2-imidazoline containing the guanidino moiety exhibited the positive-ion peaks in matrix-assisted laser desorption/ionization (MALDI) mass spectra with appreciably enhanced intensities. As expected from the reaction mechanism, the carboxyl groups of aspartic and glutamic acid residues were not modified, while the amino groups that could react with the activated peptides were concomitantly protected by formylation. The MALDI peaks corresponding to the C-terminal peptide fragments of proteins were specifically enhanced, discriminating against those from internal peptides that were not tagged with a positive charge. In favorable cases, the C-terminal peptide fragments were clearly discerned by MALDI-MS after chymotryptic digestion and were identified by their MALDI postsource decay analysis. Based on these results, we suggest a method for C-terminal sequencing of a protein.     

Development of fast-scanning laser probe system based on knife-edge method for diagnosis of RF surface acoustic wave devices

This paper describes the development of a high-speed laser probe system for surface acoustic wave (SAW) devices. A fast scanning rate of 2.5 kS/s is realized by continuous stage translation and successive acquisition of the detector output by a high-speed data-logger. Trigger pulses are generated from the output of a high-precision linear-scale installed in the translation stage and fed to the data-logger for the synchronization with the stage movement. The phase-sensitive, knife-edge method is used for the optical detection. This makes the system very unsusceptible to low-frequency mechanical vibration caused by the fast stage translation. The system is applied for the characterization of spurious resonance modes in SAW devices. In conjunction with skillful use of image processing in wavenumber domain, it is shown how the present system is effective in the diagnosis and development of SAW devices.     

A new probabilistic seismic hazard assessment for greater Tokyo

Tokyo and its outlying cities are home to one-quarter of Japan's 127 million people. Highly destructive earthquakes struck the capital in 1703, 1855 and 1923, the last of which took 105,000 lives. Fuelled by greater Tokyo's rich seismological record, but challenged by its magnificent complexity, our joint Japanese-US group carried out a new study of the capital's earthquake hazards. We used the prehistoric record of great earthquakes preserved by uplifted marine terraces and tsunami deposits (17 M approximately 8 shocks in the past 7000 years), a newly digitized dataset of historical shaking (10000 observations in the past 400 years), the dense modern seismic network (300,000 earthquakes in the past 30 years), and Japan's GeoNet array (150 GPS vectors in the past 10 years) to reinterpret the tectonic structure, identify active faults and their slip rates and estimate their earthquake frequency. We propose that a dislodged fragment of the Pacific plate is jammed between the Pacific, Philippine Sea and Eurasian plates beneath the Kanto plain on which Tokyo sits. We suggest that the Kanto fragment controls much of Tokyo's seismic behaviour for large earthquakes, including the damaging 1855 M approximately 7.3 Ansei-Edo shock. On the basis of the frequency of earthquakes beneath greater Tokyo, events with magnitude and location similar to the M approximately 7.3 Ansei-Edo event have a ca 20% likelihood in an average 30 year period. In contrast, our renewal (time-dependent) probability for the great M > or = 7.9 plate boundary shocks such as struck in 1923 and 1703 is 0.5% for the next 30 years, with a time-averaged 30 year probability of ca 10%. The resulting net likelihood for severe shaking (ca 0.9 g peak ground acceleration (PGA)) in Tokyo, Kawasaki and Yokohama for the next 30 years is ca 30%. The long historical record in Kanto also affords a rare opportunity to calculate the probability of shaking in an alternative manner exclusively from intensity observations. This approach permits robust estimates for the spatial distribution of expected shaking, even for sites with few observations. The resulting probability of severe shaking is ca 35% in Tokyo, Kawasaki and Yokohama and ca 10% in Chiba for an average 30 year period, in good agreement with our independent estimate, and thus bolstering our view that Tokyo's hazard looms large. Given 1 trillion US dollars estimates for the cost of an M approximately 7.3 shock beneath Tokyo, our probability implies a 13 billion US dollars annual probable loss.     

Novel DNA nano-patterning design method utilizing poly-L-lysine patterning by nanoimprint lithography

The DNA properties have been deliberated to comprehend new functional bio-devices. However there are few reports on DNA nano-patterning to make them. Therefore, we have tried DNA nano-patterning by using a nanoimprint process. A substrate coated with a poly-L-lysine was heated at 120 degrees C for 5 min in atmosphere, and nanoimprint carried out at 120 degrees C, 6 MPa, 5 min, and we applied 1 mg/ml DNA solution on the substrate and immobilized with the poly-L-lysine. Finally the substrate was washed at twice in water and at once in hot water intensely. DNA lines that consist of lines at about 700 nm as line width was obtain, and the very fine lines correspond to convex patterns of the mold surface. These results suggest that the imprint would make the poly-L-lysine reform by exposing it under high pressure and high temperature. Therefore since DNA is immobilized with the amino group in the poly-L-lysine, a lot of amino group would expose on the surface by the imprint from the balk, and would be patterned DNA.     

Pre-evaluation method for the spectroscopic properties of YAG bulk materials by sol–gel synthetic YAG powder

We propose a convenient method for pre-evaluating the spectroscopic properties of luminescent impurity doped YAG by sol–gel synthetic powder. Three synthetic methods, the sol–gel, normal-strike, and reverse-strike methods, are examined for their ability as a predictor and the sol–gel method proved the most effective of the three in experiments on crystallinity, particle size, and spectroscopic properties. The sol–gel Nd:YAG powder agrees well with that of a single crystal or ceramic YAG regarding the luminescent spectrum, the intensity, and the lifetime, even though the powder sintered at a low temperature of 1100 °C in comparison with the YAG crystal melting point of 1970 °C. These facts suggest that the sol–gel synthetic powder is the most effective and the easiest technique for evaluating spectroscopic properties of bulk YAG materials before fabricating the final materials.     

Synthesis of methyl boron nitride film as low-k insulating film for LSI interconnection

Low dielectric constant (k) materials for the ULSI interconnect insulator are required to meet the fast development of high-speed devices. We have investigated low-k material of boron nitride containing methyl (methyl boron nitride) by using tris-di-methyl-amino-boron (TMAB) gas. The dielectric constant (k) of the film decreases with decreasing RF plasma power and the k value of the methyl BN film can be achieved as low as 1.8 at 10 W RF plasma power.Absorption band of the film was observed at 2960 cm^? 1 due to unsymmetrical stretching mode of C–H in CH₃. It is thought that increasing C–H bond with low polarizability and reducing CN bond with high polarizability can realize a lower k value. The film has also high resistivity of more than 1 × 10⁹ Ω cm and sufficient Young modulus of more than 26 GPa for the interlayer of LSI interconnection. There is a possibility that the dielectric constant can be decreased keeping the BN structure with high strength. The methyl BN film is an extremely attractive material as low-k material of next generation devices.     

Induced radioactive nuclides of 10-MeV radiotherapy accelerators detected by using a portable HP-Ge survey meter

The radioactivation of linear accelerator components for radiation therapy is interest for radiation protection in general, and particularly, when decommissioning these structures. The energy spectra of gamma rays emitted from the heads of two accelerator models, EXL-15SP and Clinac iX, after 10-MeV X-ray irradiation, were measured using a high-purity germanium semiconductor survey meter. After spectrum analyses, activities of (24)Na, (28)Al, (54)Mn, (56)Mn, (57)Ni, (58)Co, (60)Co, (64)Cu, (65)Zn, (122)Sb, (124)Sb, (181)W, (187)W, (196)Au, and (198)Au were detected. One centimetre deep dose-equivalent rate of the heads of the linear accelerator was measured using the survey meter. The dose rate decreased to ～10 % of its initial rate after 1 week. Long-term activations were few, the radioactivity level was low, and a cooling time of several days was effective for reducing dose rate to an acceptable level for decommissioning.     

Evaluation of infrared-reflection absorption spectroscopy measurement and locally weighted partial least-squares for rapid analysis of residual drug substances in cleaning processes

The usefulness of infrared-reflection absorption spectroscopy (IR-RAS) for the rapid measurement of residual drug substances without sampling was evaluated. In order to realize the highly accurate rapid measurement, locally weighted partial least-squares (LW-PLS) with a new weighting technique was developed. LW-PLS is an adaptive method that builds a calibration model on demand by using a database whenever prediction is required. By adding more weight to samples closer to a query, LW-PLS can achieve higher prediction accuracy than PLS. In this study, a new weighting technique is proposed to further improve the prediction accuracy of LW-PLS. The root-mean-square error of prediction (RMSEP) of the IR-RAS spectra analyzed by LW-PLS with the new weighting technique was compared with that analyzed by PLS and locally weighted regression (LWR). The RMSEP of LW-PLS with the proposed weighting technique was about 36% and 14% smaller than that of PLS and LWR, respectively, when ibuprofen was a residual drug substance. Similarly, LW-PLS with the weighting technique was about 39% and 24% better than PLS and LWR in RMSEP, respectively, when magnesium stearate was a residual excipient. The combination of IR-RAS and LW-PLS with the proposed weighting technique is a very useful rapid measurement technique of the residual drug substances.