Specific determination of bromate in bread by ion chromatography with ICP-MS

A sensitive method for detecting bromate in bread by ion chromatography with inductively-coupled plasma mass spectrometry (IC/ICP-MS) was developed. Bromate was extracted from bread with water. The clean-up procedure included a 0.2 micron filter, a C18 cartridge for defatting, a silver cartridge to remove halogen anions, a centrifugal ultrafiltration unit to remove proteins, and a cation-exchange cartridge to remove silver ions. A 500 microL sample solution was applied to IC/ICP-MS. The detection limit and the quantitation limit of bromate in the solution were 0.3 ng/mL and 1.0 ng/mL, expressed as HBrO3, respectively, which corresponded to 2 ng/g and 5 ng/g, respectively, in bread. Recovery of bromate was about 90%, and the CV was about 2%. Based on the detection limit in solution and recovery from bread, the detection limit of bromate in bread was estimated to be 2 ng/g.     

Long‐term performance degradation of various kinds of photovoltaic modules under moderate climatic conditions

Various kinds of photovoltaic (PV) modules have been developed and practically operated as PV systems up to present. Investigation of the long‐term reliability of PV modules is indispensable for the use of PV systems as reliable energy sources. In this study, we show the results of outdoor exposure test in which the performance of 14 PV modules composed of five different kinds made by six different PV manufacturers have been measured since July 2004. The average performance is calculated in each year from 2005 to 2008, and the performance degradation is quantitatively evaluated. The results are that the magnitude of the performance degradation can be clearly classified by the kinds of the PV modules. The performance difference of the single‐crystalline silicon (sc‐Si) modules between 2005 and 2008 is from 1.9% to 2.8%. Polycrystalline silicon (pc‐Si) modules show performance degradation from 0.7% to 1.4%. The performance of an amorphous silicon/crystalline silicon (a‐Si:H/c‐Si) decreased by 0.7%. Although a pair of a‐Si modules had been already exposed to sunlight for about 6 months, the pair of modules show 4.4% of performance degradation. More than half of the performance degradation happened during the initial period from 2005 to 2006. This indicates that it takes about 2 years until the performance of a‐Si modules is stable. The performance is quite stable after 2006. Interestingly, the performance of the cupper indium gallium diselenide modules in 2008 is about 0.8% higher than that in 2005. Copyright © 2010 John Wiley & Sons, Ltd.     

Beef texture characterization using internationally established texture vocabularies in ISO5492:1992: Differences among four different end-point temperatures in three muscles of Holstein steers

‘Tenderness’ has been an important sensory characteristic for beef, although ‘tenderness’ has not been commonly defined. On the other hand, ISO5492:1992 provides internationally established vocabularies for sensory analysis with simple definition. The aim of this study was texture characterization for three beef muscles cooked to four end-point temperatures using ISO5492:1992 texture terms in Japanese to develop objective sensory evaluation terms for beef texture other than ‘tenderness.’ Longissimus, semitendinosus, and psoas major muscles harvested from three Holstein steers were cooked to 45, 60, 72, and 92 °C end-point temperatures and evaluated by a trained sensory panel. Correspondence analysis indicated that the ‘chewiness’ and ‘hardness’ defined in ISO5492 were distinguished in each muscle. Changes in the ‘chewiness’ and ‘hardness’ qualities during cooking were different from each other. These findings suggest that both ‘chewiness’ and ‘hardness’ as defined in ISO5492:1992 should be evaluated simultaneously to determine the sensory texture of beef.     

Logistic label propagation

In this paper, we propose a novel method for semi-supervised learning, called logistic label propagation (LLP). The proposed method employs the logistic function to classify input pattern vectors, similarly to logistic regression. To cope with unlabeled samples as well as labeled ones in the semi-supervised learning framework, the logistic functions are learnt by using similarities between samples in a manner similar to label propagation. In the proposed method, these two methods of logistic regression and label propagation are effectively incorporated in terms of posterior probabilities. LLP estimates the labels of input samples by using the learnt logistic function, whereas the method of label propagation has to optimize the whole labels whenever an input sample comes. In addition, we suggest the way to provide proper parameter setting and initialization, which frees the users from determining a parameter value in trial and error. In experiments on classification (estimating labels) in the semi-supervised learning framework, the proposed method exhibits favorable performances compared to the other methods.     

Characterization and thermodynamic study of humic acid in deep groundwater at Horonobe,Hokkaido, Japan

In this study, humic substances (humic acid and fulvic acid) were isolated from deep groundwater at ?350 m depth of Horonobe, Hokkaido, Japan to compare the characteristic property and reaction mechanism with generic humic acid isolated from surface soils. The size distributions of Horonobe humic substances were analyzed by size exclusion chromatography, flow-field flow fractionation, and total organic carbon measurement with ultrafiltration. All of them indicated small molecular weight and particle size of Horonobe humic acid in comparison with generic humic acids. Additionally, the simple protonation behavior of Horonobe humic substances similar to benzoic acid and/or phenol was revealed by thermodynamic quantities obtained by potentiometry and calorimetry. Consequently, molecular size and the reaction mechanism of Horonobe humic substances are different from generic humic acids, due to the characteristic origin.     

Experimental investigation of distributed navigation and collision avoidance for a robotic swarm

Artificial Life and Robotics - In this study, we focus on the navigation of a robotic swarm and perform an experimental investigation. A decentralized control method using only local information...