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.     

Analysis of the IgE-epitope of Der f 2, a major mite allergen, by in vitro mutagenesis

Der f 2 is a major mite allergen composed of 129 amino acid residues. To determine the major epitopes on Der f 2 recognized by human IgE antibodies, artificial mutations were introduced to Der f 2 protein. The IgE-binding activity of Der f 2 was significantly decreased by deletion of 10 amino acids at the N-terminus or nine amino acids at the C-terminus. Site-directed mutagenesis with a single amino acid replacement by Ala or Leu in both N- and C-terminal regions as well as a central portion was performed to generate 42 single-site mutations. Amino acid replacement around a disulfide bond of Cys8-Cys119 caused a marked decrease in IgE-binding activity. Furthermore, a distinct decrease in IgE-binding was also caused by Ala-substitution close to a disulfide bond of Cys73-Cys78 and by mutations of a few charged residues. From these results, it was concluded that the two disulfide-forming regions of Der f 2 and several charged residues are important for forming major epitope structures recognized by human IgE antibodies.     

Electron-microscopic procedure for acrylic rubber

The electron-microscopic visualization of acrylic rubber dispersed in a heterogeneous structural resin composition consisting of a rubber-modified two-phase plastic comprising essentially a butyl acrylate rubber phase and an acrylonitrile–styrene copolymer phase, respectively, has been accomplished. This procedure consists of the following: The molded resin specimen is treated with hydrazine hydrate solution to produce the acrylic acid hydrazides. Allow the treated specimen to soak in osmium tetroxide solution. The acrylic rubber may be indirectly fixed and stained. Some micrographs of ultrathin sections of two or three resin compositions, cut by an ultramicrotome, are presented.     

Synthesis of poly(tetrahydrofuran-b-ε-caprolactone) macromonomer via the Sml2-induced transformation

Summary A novel well-defined macromonomer consisting of different types of monomers in polymerization mechanisms was synthesized for the first time through the SmI₂-induced transformation. The macromonomer, -methacryloylpoly-(tetrahydrofuran-b--caprolactone), was prepared by the reaction of methacryloyl chloride with living poly(tetrahydrofuran-b--caprolactone) [poly(THF-b-CL)] which was obtained by the two-electron reduction of the cationic growing center of poly(THF) by samarium iodide (SmI₂) followed by the polymerization of CL. ¹H NMR analysis indicated the quantitative introduction of the methacryloyl group onto the polymer end. The molecular weight distribution of the macromonomer was relatively narrow, and the unit ratio of THF to CL could be controlled by both polymerization time of THF and the amount of CL, resulting from the living nature of both CL- and THF-polymerizations. Radical copolymerization of the produced macromonomers with methyl methacrylate in the presence of AIBN resulted in a polymethacrylate backbone grafted with poly(THF-b-CL) block copolymers.     

Photocatalytic Activity of a TiO<Subscript>2</Subscript> Photocatalyst Doped with C<Superscript>4+</Superscript> and S<Superscript>4+</Superscript> Ions Having a Rutile Phase Under Visible Light

C⁴⁺ and S⁴⁺-codoped titanium dioxide (TiO₂) having a rutile phase was prepared. By doping C⁴⁺ and S⁴⁺ ions into a TiO₂ lattice, the absorption edge of rutile TiO₂ powder was largely shifted from 400 to 700 nm. 2-Methylpyridine and methyleneblue were photocatalytically oxidized at high efficiency on C⁴⁺ and S⁴⁺-doped TiO₂ under visible light at a wavelength longer than 5 nm.     

Quantitative determination of corrosion products and adsorbed water on copper in humid air containing SO2 by IR-RAS measurements

The time dependency of the amounts of corrosion products and co-existing adsorbed water on copper in humid air containing SO₂ was estimated from a series of in situ time-resolved IR-RAS spectra on the basis of the relations between the band intensities and the mass changes of the corrosion products, which were determined by simultaneous measurement of IR-RAS and QCM. The amounts of both corrosion products increased slowly at the initial stage and later increased rapidly. Although the relative humidity was kept constant, the amount of adsorbed water increased nearly the same behavior as that of corrosion products in the stage of relatively small amounts of corrosion products and later increased rapidly when the amounts of corrosion products increased. In humid air without SO₂, sulfite gradually decomposed and some of it changed into sulfate.     

Data Center as a Key Player of a District Electric Power and Heat Network System： A Comparison in Urban and Suburb Regions

A DC （data center） demands air-conditioning power as large as the 1/3-1/2 of total electricity consumption. Thus, energy saving of cooling power of DC yields considerable effect on both economic and environmental views. PV （Photovoltaic） and absorption refrigerator with CGS （cogeneration systems） or gas boiler are possible power saving options. The waste warm air from DC would be utilized for greenhouse heating when DC and greenhouse locate near in the suburbs. In this study, the authors develop an energy network model to assess the potential contribution of DC as a major electric power and chilled air consumer as well as the warm air supplier in a district to the energy efficiency improvement. The evaporation heat of LNG （liquefied natural gas） utilization is also considered as well as PV, CGS. This model is applied to the cases of the urban area in Tokyo which involves athletic center, shops and hospital and the suburbs including greenhouse and then compared.     

A design of high optical efficiency wedge type light guide plate adopting twin inclined cylindrical surface

We propose wedge type light guide plate (LGP) adopting twin inclined cylindrical surfaces (TICS) at the incident part of a LGP. It has higher optical efficiency than conventional wedge type LGP. In dimension of LGP which the thickness of incident part is 1.5 mm and that of luminance part is 0.7 mm, the optical efficiency of wedge type LGP adopting TICS is expected to be 96% in comparison with a normal flat LGP. In addition, there is an advantage to reduce the non‐uniformity of vicinity of light emitted diodes (LEDs) by TICS reflecting light laterally. However, it is necessary that the LED centers are aligned with the intersections of TICS. The misalignment of LED causes non‐uniformity of optical profile that is slightly larger than a normal LGP.     

Molecular characterization of antibiotic-resistant salmonella isolates from retail meat from markets in northern Vietnam

A total of 118 Salmonella isolates were detected from 283 retail meat samples (135 pork and 148 chicken meat) purchased at retail markets in Northern Vietnam. Thirteen serovars, including Infantis, Anatum, Rissen, Reading, Emek, Typhimurium, Blockley, London, Newport, Derby, Weltevreden, Albany, and Hadar, were determined. Resistance to tetracycline (54.2%), sulfonamides (52.5%), streptomycin (41.5%), trimethoprim (36.4%), chloramphenicol (35.6%), and ampicillin (33.1%) was commonly seen in the Salmonella isolates. Fourteen [bla(TEM), bla(OXA-1), bla(PSE-1), aadA1, sul1, tetA, tetB, tetG, cmlA1, floR, dfrA1, dfrA12, aac(3)-IV, and aphA1-1AB ] of 17 resistance genes were detected from the isolates demonstrating resistance. Genes for plasmid-mediated quinolone resistance, such as qnrA, qnrB, qnrS, qepA, and acc(6')-1b-cr, were not detected in 23 quinoloneresistant isolates. The substitution TCC to TTC at codon 83 of gyrA was found in the 18 quinolone-resistant isolates. The data revealed that resistant Salmonella strains were widely distributed in Northern Vietnam via the food chain and that they might contain multiple genes specifying identical resistance phenotypes. Thus, further studies are necessary to clarify the mechanisms of antibiotic resistance in Salmonella strains and their spread in the livestock market.     

Morphology of CuO through precipitation process under 2.45 GHz microwave irradiation

The morphology of CuO powders formed by a homogeneous precipitation process from aqueous copper precursor complex was investigated. The effect of 2.45 GHz microwave irradiation appeared in the characteristic morphology of the CuO microcrystal with comparison of an ordinal synthesis process. The crystallographic orientation of CuO microcrystals in the particle was examined by HRTEM. Using microwave irradiation, it was demonstrated that the morphology of the particles was kept through the decomposition of the precursor. Also the rapid transformation of a precursor to CuO in aqueous solution under microwave irradiation condition was discussed.