The Function of Sialidase Revealed by Sialidase Activity Imaging Probe

Sialidase cleaves sialic acid residues from glycans such as glycoproteins and glycolipids. In the brain, desorption of the sialic acid by sialidase is essential for synaptic plasticity, learning and memory and synaptic transmission. BTP3-Neu5Ac has been developed for sensitive imaging of sialidase enzyme activity in mammalian tissues. Sialidase activity in the rat hippocampus detected with BTP3-Neu5Ac increases rapidly by neuronal depolarization. It is presumed that an increased sialidase activity in conjunction with neural excitation is involved in the formation of the neural circuit for memory. Since sialidase inhibits the exocytosis of the excitatory neurotransmitter glutamate, the increased sialidase activity by neural excitation might play a role in the negative feedback mechanism against the glutamate release. Mammalian tissues other than the brain have also been stained with BTP3-Neu5Ac. On the basis of information on the sialidase activity imaging in the pancreas, it was found that sialidase inhibitor can be used as an anti-diabetic drug that can avoid hypoglycemia, a serious side effect of insulin secretagogues. In this review, we discuss the role of sialidase in the brain as well as in the pancreas and skin, as revealed by using a sialidase activity imaging probe. We also present the detection of influenza virus with BTP3-Neu5Ac and modification of BTP3-Neu5Ac.     

The effect of Na addition on the first hydrogen absorption kinetics of cast hypoeutectic Mg–La alloys

With superior properties of Mg such as high hydrogen storage capacity (7.6 wt% H/MgH₂), low price, and low density, Mg has been widely studied as a promising candidate for solid-state hydrogen storage systems. However, a harsh activation procedure, slow hydrogenation/dehydrogenation process, and a high temperature for dehydrogenation prevent the use of Mg-based metal hydrides for practical applications. For these reasons, Mg-based alloys for hydrogen storage systems are generally alloyed with other elements to improve hydrogen sorption properties. In this article, we have added Na to cast Mg–La alloys and achieved a significant improvement in hydrogen absorption kinetics during the first activation cycle. The role of Na in Mg–La has been discussed based on the findings from microstructural observations, crystallography, and first principles calculations based on density functional theory. From our results in this study, we have found that the Na doped surface of Mg–La alloy systems have a lower adsorption energy for H₂ compared to Na-free surfaces which facilitates adsorption and dissociation of hydrogen molecules leading to improvement of absorption kinetic. The effect of Na on the microstructure of these alloys, such as eutectic refinement and a density of twins is not highly correlated with absorption kinetics.     

Structure and electrical characteristics of Ce4+-doped Ba2In2O5

The In-site of Ba₂In₂O₅ with Brownmillerite structure was partially substituted for Ce⁴⁺ ions in order to examine the doping effect on the order-disorder transition. Ba₂In_{2 – x} Ce _x O_{5 + x/2} (x = 0.1, 0.2, 0.3, 0.5, 1.0, and 1.5) were prepared by solid state reaction. X-Ray diffraction analyses of these powder samples demonstrated that Ba₂In_{2 – x} Ce _x O_{5 + x/2} (x = 0.1 and 0.2) possesses Brownmillerite structure. With increasing content of Ce⁴⁺ ion the crystal system of Ba₂In_{2 – x} Ce _x O_{5 + x/2} (x = 0.3, 0.5, and 1.0) changed to cubic perovskite structure above the order-disorder transition temperature of Ba₂In₂O₅. Arrhenius plots of the electrical conductivities of Ba₂In_{2 – x} Ce _x O_{5 + x/2} (x = 0.2, 0.3, and 1.0) exhibited no discontinuity. These compounds had high transference numbers of oxide ion above 973 k.     

Effects of post annealing on removal of defect states in silicon oxynitride films grown by oxidation of silicon substrates nitrided in inductively coupled nitrogen plasma

Ultra thin (5 nm) silicon oxynitride (SiON) films were fabricated at a low temperature using nitrogen plasma generated by an inductively coupled plasma system. Effects of post-metalization annealing (PMA) of Al/SiON/Si MOS structure on the electrical properties of the SiON films were studied and correlations between the charge trapping states and the leakage current were established. Positive charge trapping by interface states generated by plasma damage was characterized by the hysteresis in high-frequency capacitance-voltage (C-V) characteristics. Hysteresis was observed to be completely removed by PMA while interface state density at the Si mid band gap reduced from 2.2×10¹³ to 3.7×10¹¹/eV/cm² and the oxide fixed charge density changed from 3.3×10¹² to −4×10¹¹/cm². The leakage current also decreased significantly, by more than two orders of magnitude, with PMA. The analysis of the leakage current using trap assisted tunneling (TAT) mechanism indicated that with PMA, the trap energy level in the SiON film becomes shallower from 1.3 to 0.7 eV. The positive trapped charges were observed to be annihilated by PMA and the trapping sites became neutral trap centers in the SiON film. This could lead to the reduction in the leakage current component given rise to by TAT.     

EFFECT OF DEVELOPER PROPERTIES ON PRINT QUALITY

We investigated the dependence of the toner charge-to-mass ratio (q/m) in a two-component electrophotographic developer on the shaking time, toner concentration (T/C), carrier sizes, and the carrier core and the coating materials, as well as the resulting print qualities in terms of print density, background density, tone reproduction, resolution, and dot gain. Four different sizes of spherical ferrite carriers, four different carrier coating materials, and an irregular iron carrier were used with two types of toner: 14 um red toner (NP-4080) and 8 um cyan toner (CLC-500). The q/m measurement by the blow-off method showed that the red toner charge was positive while the cyan toner charge was negative with these carriers. The toner q/m values, which depended on the shaking time and decreased with the increasing T/C were much more affected by the larger carrier and the smaller toner. The carriers which yielded charges in the proper range produced better print qualities than did the other carriers that yielded a toner q/m     

Lead content of rice collected from various areas in the world

Rice samples consumed by local populations were collected between 1990 and 1995 in 17 areas in the world, mostly from Asia (10 areas), but also from 7 areas outside of Asia. In total, 1528 samples were obtained (about one half from Japan) and were analyzed for lead (Pb) by electrothermal atomic absorption spectrometry. When the Pb contents in rice samples were classified into 10 areas in Asia, the highest and the lowest geometric means (GMs) were for Indonesia (38 ng/g) and Australia (2 ng/g), respectively. Among 7 regions outside Asia, the GM was highest for Spain (58 ng/g) and the lowest for the USA. (3 ng/g). Moreover, inter-regional differences were significant, when more than 100 samples from one area were divided into 3-9 regions and GMs for regions were compared. There was a marked difference in Pb contents in rice by areas and regions in the world. Nevertheless, comparison by area of the present results with those reported in literature show that there has been no substantial reduction in Pb in rice in the past decade either in Japan or elsewhere in the world.     

Spontaneous disappearance of traumatic macular holes in young patients

PURPOSE: To report the disappearance of traumatic macular hole in three eyes of three patients. METHODS: Clinical data of the patients were reviewed. RESULTS: The three patients were relatively young, ranging in age from 12 to 18 years old. In one eye of each patient, a small traumatic macular hole was observed at the first visit. Visual acuities ranged from 20/100 to 20/40. The macular holes resolved spontaneously 3 to 4 months after the trauma, and final visual acuity improved to 20/20 in all patients. CONCLUSION: Small traumatic macular holes in young patients can resolve spontaneously, and this can be associated with good visual recovery.     

Breakdown characteristics of oil and paper insulation for a very fast transient voltage

This paper describes the dielectric breakdown characteristics of oil and oil‐impregnated paper for very fast transient (VFT) voltages. Blumlein circuits generate VFT voltages of 60 and 300 ns in a pulse width that simulates disconnecting switching surges in gas‐insulated switch gears. We measured the breakdown voltages of needle‐to‐plane, plane‐to‐plane oil gaps and several pieces of paper between plane electrodes for VFT and lightning impulse voltages. The measured data were formulated in V‐t characteristics and Weibull probability distributions. The inclination n of V‐t characteristics of insulating paper is 150, which is less than n = 13.7 of the plane‐to‐plane oil gap in the VFT time range. The shape parameters of Weibull distribution obtained in this study show that the scattering of breakdown voltages of paper is much less than that of oil. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 16–24, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10043