Synthesis and Antifungal Activity of Some Organotin(IV) Carboxylates

Six diorganotin(IV) carboxylates prepared by reacting diorganotin(IV) dichlorides with the respective silver carboxylate have been tested for antifungal activity against Aspergillus. niger, Aspergilluus flavus and Pencillium. citrinum in Sabourand dextrose broth. The compounds generally exhibit greater fungitoxicity than the diorganotin(IV) dichlorides and the carboxylic acids from which they were synthesized. In keeping with the generally accepted notion that the organotin moiety plays an important role in deciding the antifungal activity of an organotin compound, the diphenyltin(IV) compounds were more active than their di-n-butyltin(IV) analogues. However, the order of increasing fungitoxicity of the compounds parallels that of the uncomplexed carboxylic acids. The implications of the results are discussed.     

Changes in thyroid state affect pHi and Nai+ homeostasis in rat ventricular myocytes

We have tested the hypothesis that thyroid state may influence both the flow of cellular Ca2+ and the myofilament response to Ca2+ by effects on intracellular pH (pHi) and Na+ (Nai+). Single cardiac myocytes isolated from hypothyroid, euthyroid and hyperthyroid animals were loaded with fura-2/AM (Cai2+ probe), BCECF/AM (pHi probe) or SBFI/AM (Nai+ probe). Compared with hypothyroid animals, myocytes isolated from hyperthyroid rat hearts demonstrated a significant: (1) increase in extent of shortening; (2) decrease in the time to peak contraction; (3) increase in the peak amplitude of the fura-2 fluorescence ratio; (4) decrease in pHi (DeltapHi=0. 19+/-0.05); and (5) increase in Nai+ (DeltaNai+=2.88+/-0.55 mM). We have also compared pHi in Langendorff perfused hypo- and hyperthyroid rat hearts using NMR. We have found that hyperthyroid hearts are 0.15+/-0.03 pH units more acidic than hypothyroid hearts. Analysis of mRNA levels demonstrated that hyperthyroidism increased expression of both the Na+/Ca2+ exchanger and Na+/H+ antiporter, and decreased expression of Na+ channel mRNAs. These changes appear partially responsible for the observed changes in Nai+ and pHi. Our results provide the first evidence that changes in cardiac contractility associated with altered thyroid state not only involve effects on Ca2+, but may also involve changes in the response of the myofilaments to Cai2+mediated by altered pHi and Nai+.     

Structure extraction from decorated characters using multiscaleimages

Decorated characters are widely used in various documents. Practical optical character reader is required to deal with not only common fonts but also complex designed fonts. However, since the appearances of decorated characters are complicated, most general character recognition systems cannot give good performances on decorated characters. In this paper, an algorithm that can extract character's essential structure from a decorated character is proposed. This algorithm is applied in preprocessing of character recognition. The proposed algorithm consists of three procedures: global structure extraction, interpolation of structure and smoothing. By using multiscale images, topographical features, such as ridges and ravines are detected for structure extraction. Ridges are used for extracting global structure and ravines are used for interpolation. Experimental results show character structures can be clearly extracted from very complex decorated characters     

Fast template matching with polynomials.

Template matching is widely used for many applications in image and signal processing. This paper proposes a novel template matching algorithm, called algebraic template matching. Given a template and an input image, algebraic template matching efficiently calculates similarities between the template and the partial images of the input image, for various widths and heights. The partial image most similar to the template image is detected from the input image for any location, width, and height. In the proposed algorithm, a polynomial that approximates the template image is used to match the input image instead of the template image. The proposed algorithm is effective especially when the width and height of the template image differ from the partial image to be matched. An algorithm using the Legendre polynomial is proposed for efficient approximation of the template image. This algorithm not only reduces computational costs, but also improves the quality of the approximated image. It is shown theoretically and experimentally that the computational cost of the proposed algorithm is much smaller than the existing methods.     

Pattern recognition using boundary data of component distributions

In statistical pattern recognition, a Gaussian mixture model is sometimes used for representing the distribution of vectors. The parameters of the Gaussian mixture model are usually estimated from given sample data by the expectation maximization algorithm. However, when the number of data attributes is large, the parameters cannot be estimated correctly. In this paper, we propose a novel approach for estimating the parameters of the Gaussian mixture model by using sample data located on the boundary of regions defined by the component density functions. Experiments are carried out to show the characteristics of the proposed method.     

自学习模糊逻辑推理网络及模糊控制器的构成

提出了一种自学习模糊逻辑推理网络和自学习模糊控制器的构成方法.这种方法是 把RCE(Restricted Coulomb Energy)模型进行扩展.使其能够进行模糊逻辑推理,并用于构 成基于RCE模型的自学习模糊控制器RLFC(RCE—based Learning Fuzzy controller).这种 方法有以下特点:a)学习速度高.追加学习容易;b)网络的信息处理工作单元的个数由自学习 决定,通用性好;c)不存在局部极小点问题.自学习模糊控制器RLFC可以直接把熟练者的操 作知识转换成模糊控制规则,自动构成模糊控制器.数值仿真实验表明其效果良好.     

Synthesis of Cycloparaphenylenes and Related Carbon Nanorings: A Step toward the Controlled Synthesis of Carbon Nanotubes

Since their discovery in 1991, carbon nanotubes (CNTs) have attracted significant attention because of their remarkable mechanical, electronic, and optical properties. Structural uniformity of the CNT is critically important because the sidewall structures (armchair, zigzag, and chiral) determine many of the significant properties of CNTs. Ideally researchers would synthesize CNTs with a defined target sidewall structure and diameter, but the current synthetic methods, such as arc discharge and chemical vapor deposition, only provide CNTs as the mixtures of various structures. Purification of these mixtures does not allow researchers to isolate a structurally uniform CNT, which is the bottleneck for fundamental studies and advanced applications of these materials. Therefore, the selective and predictable synthesis of structurally uniform CNTs would represent a critical advance in both nanocarbon science and synthetic chemistry. This Account highlights our efforts toward the bottom-up synthesis of structurally uniform carbon nanotubes (CNTs). We envisioned a bottom-up synthesis of structurally uniform CNTs through a controlled growth process from a short carbon nanoring (template) that corresponds to the target structure of CNTs. Our simple retrosynthetic analysis led to the identification of cycloparaphenylenes (CPPs), acene-inserted CPPs, and cyclacenes as the shortest sidewall segments of armchair, chiral, and zigzag CNTs, respectively. With this overall picture in mind, we initiated our synthetic studies of aromatic rings/belts as an initial step toward structurally uniform CNTs in 2005. This research has led to (i) a general strategy for the synthesis of CPPs and related carbon nanorings using cyclohexane derivatives as a benzene-convertible L-shaped unit, (ii) a modular, size-selective, and scalable synthesis of [n]CPPs (a shortest segment of armchair CNTs), (iii) the X-ray crystal structure analysis of CPPs, (iv) the design and synthesis of acene-inserted CPPs as the shortest segment of chiral CNTs, and (v) the first synthesis of cyclo-1,4-naphthylene, a π-extended CPP. We believe this work will serve as important initial steps toward a controlled synthesis of CNTs.     

A GIS-based risk assessment of hydrogen transport: Case study in Yokohama City

This study proposes a method of assessing the risk of hydrogen transport via road considering spatial features of a transport route, based on a geographic information system (GIS); a case study of Yokohama, Japan was considered in the assessment. The risk determined by multiplying the frequency of accidents with their consequences was estimated using road segments constituting the entire transport route. The effects of road structure, traffic volumes, and population information were reflected in the estimation of the risk for each road segment by using GIS. In the case study, the risks of transport route were assessed at an acceptable level under risk criteria. The results indicated that the risks fluctuated according to the road segments, indicating that spatial features of a transport route significantly affect the corresponding risks. Analyzing this importance indicates the transport routing to avoid high risk road segments as countermeasures.     

A handwritten character recognition system using directionalelement feature and asymmetric Mahalanobis distance

This paper presents a precise system for handwritten Chinese and Japanese character recognition. Before extracting directional element feature (DEF) from each character image, transformation based on partial inclination detection (TPID) is used to reduce undesired effects of degraded images. In the recognition process, city block distance with deviation (CBDD) and asymmetric Mahalanobis distance (AMD) are proposed for rough classification and fine classification. With this recognition system, the experimental result of the database ETL9B reaches to 99.42%