我国与日本住宅区公园绿地建设体制的对比——兼述北京市住宅区公园绿地的建设现状

本文阐述了我国住宅区的基本形态及构成、住宅区公园绿地建设的相关体制,通过对北京市住宅区中心绿地的建设现状实地调研,整理出了北京市住宅区中心绿地的现状和问题,并借鉴日本住宅区中心绿地的规划建设方法,对我国住宅区中心绿地规划建设提出建议。     

Novel in vitro screening system for monoclonal antibodies using hypermutating chicken B cell library

Here, we report an in vitro screening system for monoclonal antibodies using a hypermutating chicken B cell line, DT40-SW. When switching on hypermutation, cultured DT40-SW cells constituted an antibody library, from which clones secreting antibodies to a test antigen were successfully isolated, and genetically stabilized by switching off the mutation machinery.     

Improvement of DCT-based compression algorithms using Poisson's equation.

We propose two new image compression-decompression methods that reproduce images with better visual fidelity, less blocking artifacts, and better PSNR, particularly in low bit rates, than those processed by the JPEG Baseline method at the same bit rates. The additional computational cost is small, i.e., linearly proportional to the number of pixels in an input image. The first method, the "full mode" polyharmonic local cosine transform (PHLCT), modifies the encoder and decoder parts of the JPEG Baseline method. The goal of the full mode PHLCT is to reduce the code size in the encoding part and reduce the blocking artifacts in the decoder part. The second one, the "partial mode" PHLCT (or PPHLCT for short), modifies only the decoder part, and consequently, accepts the JPEG files, yet decompresses them with higher quality with less blocking artifacts. The key idea behind these algorithms is a decomposition of each image block into a polyharmonic component and a residual. The polyharmonic component in this paper is an approximate solution to Poisson's equation with the Neumann boundary condition, which means that it is a smooth predictor of the original image block only using the image gradient information across the block boundary. Thus, the residual--obtained by removing the polyharmonic component from the original image block--has approximately zero gradient across the block boundary, which gives rise to the fast-decaying DCT coefficients, which, in turn, lead to more efficient compression-decompression algorithms for the same bit rates. We show that the polyharmonic component of each block can be estimated solely by the first column and row of the DCT coefficient matrix of that block and those of its adjacent blocks and can predict an original image data better than some of the other AC prediction methods previously proposed. Our numerical experiments objectively and subjectively demonstrate the superiority of PHLCT over the JPEG Baseline method and the improvement of the JPEG-compressed images when decompressed by PPHLCT.     

H2O2 tolerance of Vibrio rumoiensis S-1(T) is attributable to the cellular catalase activity

The extraordinarily high level of H2O2 tolerance of Vibrio rumoiensis strain S-1(T) when compared with the tolerance levels of strain S-4, a probable catalase-deficient derivative of strain S-1(T), was demonstrated by the introduction of 0-100 mM H2O2 during the mid-exponential growth phase. The contribution of catalase to the H2O2 tolerance was also demonstrated by comparing the catalase-deficient mutant Escherichia coli strain UM2 with a UM2 strain, harboring the plasmid pBSsa1, which carried the strain S-1(T) catalase gene vktA. The decomposition rates of 23-25 mM H2O2 that was introduced in the culture fluids of strain S-1(T) and E. coli UM2 harboring pBSsa1 corresponded to the calatase activities of the cells by spectrophotometric measurements. The presence of cell surface catalase was observed by immunoelectron microscopy, using an antibody for intracellular catalase in strain S-1(T). The high level of H2O2 tolerance of strain S-1(T) was attributable to the catalase activity of the cells. Cell surface catalase is considered to contribute to the catalase activity of strain S-1(T) cells.     

Emission factor for antimony in brake abrasion dusts as one of the major atmospheric antimony sources

Abrasion tests were conducted using a brake dynamometer to determine the antimony (Sb) emission factor originating from automobiles. Abrasion dusts from commercially available brake pads (nonasbestos organic type) were emitted into an enclosed chamber under various braking conditions in terms of initial driving speed and deceleration. Suspended dusts inside the chamber were collected on a quartz fiber filter and weighed. From the experimental data, dust emission could be regressed as a function of the initial kinetic energy loading and the braking time. Using the regression function, the emission factors of brake abrasion dusts under the typical braking conditions (initial driving speed; 50 km/h, deceleration; 1.0 m/s2) were calculated as 5.8 mg/braking/car for PM10 and 3.9 mg/braking/car for PM2.5. The elemental composition of the collected dusts indicated that the fraction originating from disk wear contributed to approximately 30% of the suspended dusts. From these analytical results, it was concluded that the Sb emission factors originating from automobiles were approximately 32 microg Sb/braking/car for PM10 and 22 microg Sb/ braking/car for PM2.5. These essential data will contribute to the modeling of atmospheric Sb concentration alongside roadways and also to the better understanding of Sb source apportionment.     

Survey of synthetic disinfectants in grapefruit seed extract and its compounded products

Grapefruit seed extract (GSE), derived from the seeds of grapefruit (Citrus paradisi MCAF.), is listed as a natural food additive in Japan. Products containing GSE are used as disinfectants made from only natural sources, especially after Japanese researchers found that GSE prevents the growth of norovirus. On the other hand, recent overseas studies indicated that synthetic disinfectants, such as benzalkonium and benzethonium chlorides, were present in some commercial GSE products. To confirm the quality of commercial GSE products available in Japanese markets, we carried out comprehensive research to identify the major constituents of commercial GSE products which are used as food additives (13 products from 6 manufacturers), dietary supplements (5 products from 4 manufacturers), cosmetic materials (16 products from 10 manufacturers) and disinfectant or deodorant sprays (7 products from 7 manufacturers). By means of NMR and LC/MS analysis, synthetic disinfectants such as benzethonium or benzalkonium salts were detected in most of the commercial GSE products.     

Study on mechanism of strength distribution development in vacuum-dewatered concrete based on the consolidation theory

The strength and hardness of a concrete slab surface are considered to be significantly affected by concrete bleeding. Vacuum dewatering is reported to be quite effective in imparting high density and strength. However, in Japan, in contrast with concrete work in civil engineering applications, concrete work in the field of building construction has not been successfully treated by this method. In an earlier report, the authors pointed out the strong relationship between strength distribution and density distribution in vacuum-dewatered concrete, both of which gradually decrease from the top surface to a depth of about 15 cm. The main purpose of the present study is to discuss the mechanism of the occurrence of such distribution of strength and density, based on consolidation theory. In an experiment, pore water pressure distribution in concrete is measured by means of an original measuring system. The results of the experiment confirm that the consolidation theory is quite effective in explaining the internal properties of vacuum-dewatered concrete as well as those of press-dewatered concrete. A prediction method for the strength improvement of concrete by vacuum dewatering is also discussed. It was considered likely that pore water pressure distribution generated by vacuum dewatering could be attributable to the influences of capillary tension and viscous resistance. This mechanism was verified by model experiment.     

Electrochemical design of two-dimensional Au nanocone arrays using porous anodic alumina membranes with conical holes

We report step-by-step electrochemical design of two-dimensional (2D) Au nanocone arrays by using novel porous anodic alumina membranes with conical holes. The cones with desirable aspect ratios can be fabricated by using the PAA templates with different aspect ratios. The Au nanocone arrays show high potentials as SERS (Surface Enhanced Raman Scattering)-active substrates and Au electrodes with high surface area.