Relative Nuclease Resistance of a DNA Aptamer Covalently Conjugated to a Target Protein

A major obstacle to the therapeutic application of an aptamer is its susceptibility to nuclease digestion. Here, we confirmed the acquisition of relative nuclease resistance of a DNA-type thrombin binding aptamer with a warhead (TBA₃) by covalent binding to a target protein in the presence of serum/various nucleases. When the thrombin-inhibitory activity of TBA₃ on thrombin was reversed by the addition of the complementary strand, the aptamer was instantly degraded by the nucleases, showing that the properly folded/bound aptamer conferred the resistance. Covalently binding aptamers possessing both a prolonged drug effect and relative nuclease resistance would be beneficial for in vivo translational applications.     

Robust stability analysis with cycling-based LPTV scaling: part I. Fundamental results on its relationship with lifting-based LPTV scaling

This paper is concerned with robust stability analysis of discrete-time linear periodically time-varying (LPTV) systems using the cycling-based LPTV scaling approach. To study the properties of this approach in comparison with the lifting-based LPTV scaling approach, we consider exploiting the framework of representing the associated robust stability conditions with infinite matrices. Since it serves as a common framework for comparing the two different LPTV scaling approaches, it provides us with new insights into the relationship between the cycling-based and lifting-based scaling approaches. In particular, we derive fundamental results that enable us to reduce the comparison, with respect to conservativeness in robust stability analysis, of the two scaling approaches with restricted and tractable classes of separators to a modified comparison of the associated classes of what we call infinite-dimensional separators arising in the above infinite matrix framework.     

Development of residential PEFC cogeneration systems: Ru catalyst for CO preferential oxidation in reformed gas

The performance of the novel Ru catalyst in a single-stage CO preferential oxidation removal reactor was investigated for residential polymer electrolyte fuel cell (PEFC) cogeneration systems. The outlet CO concentration of the CO removal reactor was reduced to less than 1 ppm even at [O₂]/[CO]=1.5. The natural gas fuel processor equipped with the CO removal reactor achieved the target thermal efficiency of 77% (LHV). Moreover, the durability of the Ru catalyst has been confirmed for more than 16,000 h at a micro-reactor and for more than 8000 h at an actual CO removal reactor. Because of the low O₂/CO molar ratio, the high CO removal conversion and the long-term durability, the Ru catalyst contributes to the development of residential PEFC cogeneration systems.     

Effects of variation in exposure to airborne acetone and difference in work load on acetone concentrations in blood, urine, and exhaled air

Using a physiologically based pharmacokinetic (PBPK) model, the effects of variation of exposure concentration of acetone on three biological indicators--acetone concentrations in blood, urine, and exhaled air--were investigated. The effect of the difference in work load was also examined. It was confirmed that the model could be used to estimate acetone concentrations during fluctuating exposure by comparing simulated acetone concentrations with the corresponding values observed in field surveys. By inputting the exposure situations into the PBPK model, the variabilities of the biological indicators were simulated. The variation of acetone exposure was expressed by seven 1-hour time-weighted averages (CEXPs). The arithmetic means of the CEXPS were 200 and 750 ppm. The geometric standard deviations (GSDs) were 1.5, 2.0, and 3.0, representing low, moderate, and high variations, respectively. Work loads were set at 15 and 50 W. Consequently, there were 12 exposure situations. The acetone concentrations in venous blood (CB) and exhaled alveolar air (CA) at 1 minute after the end of the work shift were selected as biological indicators of exposure because they were predicted to decrease rapidly at the end of exposure and become relatively stable after 1 minute. The acetone concentration in urine excreted during the last 2 hours of the work shift (CU) was also used as a biological indicator. Simulation was repeated 100 times with randomly permuting CEXPs for each situation. The mean values of CB, CU, and CA showed almost no variation regardless of the difference in the GSD of CEXPs. The coefficients of variation increased with the GSD of CEXPs but were less than 0.2. Consequently, these variables were acceptable as biological indicators of daily average exposure for the same work load. However, the difference in work load greatly changed the mean values of CB, CU, and CA, thus making it difficult to use these variables as indicators of daily average exposure for different work loads.     

Extended new-type SAW-resonator-coupled filters used in duplexer for Japanese cellular radio

Cellular mobile radio operates in full duplex mode, e.g. simultaneously transmits and receives radio frequency signals. A duplexer is constructed with a transmitter final stage filter (T/sub 1/) and a receiver top filter (R/sub 1/). New SAW filters using an extended SAW-resonator-coupled structure have been developed for Japanese cellular radio. A low loss of 1.6 dB for T/sub 1/ and a high rejection level of 50 dB for R/sub 1/ have been achieved.<>     

Establishment of gastric surface mucous cell lines from transgenic mice harboring temperature-sensitive simian virus 40 large T-antigen gene

Brown adipose tissue (BAT) is the major thermogenic organ of the human neonate. To determine whether it is also active in the peripheral conversion of T4 to T3, as shown in several animal species, interscapular BAT from 13 newborns of 25-40 weeks gestational age who survived 4 days, at most, was investigated. BAT was found to contain significant amounts of the mitochondrial uncoupling protein (UCP), the rate-limiting component of heat production. The specific content of UCP increased from 29.4 +/- 3.3 to 62.5 +/- 10.2 pmol/mg protein between 25 and 40 weeks of gestation, respectively, and the UCP/F1-ATPase molar ratio, a sensitive marker of brown fat differentiation, increased similarly. BAT was also found to contain iodothyronine 5'-deiodinase (5'D), which appears to be a type II enzyme, based on high affinity for T4 (Km, 2.9 nmol/L) and insensitivity to propylthiouracil (10% inhibition by 1 nmol/L). 5'D was active by 25 weeks gestation, and the specific activity increased from 116 +/- 15 to 417 +/- 46 fmol/h.mg protein during the period examined. The development of 5'D activity was similar to the changes in UCP content; both exhibited a major increase before 32 weeks gestation. The results indicate that thermogenic function and 5'D activity develop in human BAT rather early, during the first half of the last trimester of gestation. The activities of 5'D in human BAT are comparable with 5'D activities found in animal BAT stimulated during the perinatal period, by cold exposure, or by increased cAMP levels.     

Electrical feedback and its network analysis for linewidthreduction of a semiconductor laser

The center frequency of the field spectrum of a 1.5-μm InGaAsP distributed-feedback laser was stabilized by negative electrical feedback. The resultant residual frequency fluctuation was σ=3.6×10^-11 for an integration time of 10 s. The linewidth of the field spectrum was simultaneously reduced by using another electrical feedback loop. Its minimum value was 360 kHz, which was 1/27 that of the free-running condition. This linewidth was narrower than the one determined by the magnitude of the spontaneous emission of the free-running laser. The field spectrum was very stable, and the value of the linewidth was constant for more than 40 h. Network analysis was carried out to realize further reductions of the linewidth