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Wencheng, Li,Cho, Kichul,Yamasaki, Yasuhiro,Takeshita, Satoshi,Hwang, Kiju,Kim, Daekyung,Oda, Tatsuya Elsevier 2018 Aquatic toxicology Vol.201 No.-
<P><B>Abstract</B></P> <P>The dinoflagellate <I>Heterocapsa circularisquama</I> is highly toxic to bivalves. However, significant toxicity to finfish species has not been reported. We previously found that <I>H. circularisquama</I> has light-dependent haemolytic agents. Purification and chemical structural analyses revealed that the haemolytic agent H2-a is a porphyrin derivative, which exhibits light-dependent cytotoxicity toward tumour cells. To clarify the biological activity of H2-a further, its antibacterial activities against Gram-positive and Gram-negative bacteria were investigated in this study. A fraction (F5) equivalent to H2-a purified from the methanol extract of <I>H. circularisquama</I> showed potent light-dependent bactericidal activity toward <I>Staphylococcus aureus</I>, and the activity was concentration- and light illumination time-dependent; however, <I>Escherichia coli</I> was highly resistant to F5. Electron microscopic observation suggested that F5 induces morphological changes in <I>S. aureus</I> in a light-dependent manner. Further analysis using other bacterial species showed that the Gram-positive bacterium <I>Bacillus subtilis</I> was more sensitive than the Gram-negative bacteria <I>Pseudomonas aeruginosa</I> and <I>Vibrio alginolyticus</I>. These results indicate that F5 is a photo-induced antibacterial agent with relatively higher specificity to Gram-positive bacteria. Iodometric assay suggested that singlet oxygen was generated from light-illuminated F5. Histidine, a specific singlet oxygen scavenger, markedly inhibited the photosensitising antibacterial activity of F5 against <I>S. aureus</I>, suggesting the involvement of singlet oxygen in antibacterial activity. The antibacterial spectrum of F5 was evidently different from that of 5,10,15,20-tetra (<I>N</I>,<I>N</I>,<I>N</I>-trimethylanilinium) porphyrin tetratosylate, a commercially available porphyrin compound with antibacterial activity. Our results demonstrate that <I>H. circularisquama</I> has a novel antibacterial photosensitiser, a porphyrin derivative, with relatively higher specificity to Gram-positive bacteria. To the best of our knowledge, this is the first study to discover a porphyrin derivative with antibacterial activity in marine microalga.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A porphyrin derivative (F5) with antibacterial activity was isolated from dinoflagellate <I>H. circularisquama</I>. </LI> <LI> F5 shows relatively higher specificity to Gram-positive bacteria such as <I>S. aureus</I>, but <I>E. coli</I> was highly resistant to F5. </LI> <LI> Antibacterial spectrum of F5 was evidently different from that of a commercially available porphyrin derivative. </LI> <LI> Singlet oxygen was detected in light-illuminated F5. </LI> <LI> Histidine, a singlet oxygen scavenger, inhibited the antibacterial activity of F5. </LI> </UL> </P>
Impact of feature proportion on matching performance of multi-biometric systems
Wencheng Yang,Song Wang,Guanglou Zheng,Craig Valli 한국통신학회 2019 ICT Express Vol.5 No.1
Biometrics as a tool for information security has been used in various applications. Feature-level fusion is widely used in the design of multi-biometric systems due to its advantages in increasing recognition accuracy and security. However, most existing multi-biometric systems that use feature-level fusion assign each biometric trait an equal proportion when combining features from multiple sources. For example, multi-biometric systems with two biometric traits commonly adopt a 50–50 feature proportion setting, which means that fused feature data contains half elements from each biometric modality. In this paper, we investigate the impact of feature proportion on the matching performance of multi-biometric systems. By using a fingerprint and face based multi-biometric system that applies feature-level fusion, we employ a random projection based transformation and a proportion weight factor. By adjusting this weight factor, we show that allocating unequal proportions to features from different biometric traits yields different matching performance. Our experimental results indicate that optimal performance, achieved with unequal feature proportions, could be better than the performance obtained with the commonly used 50–50 feature proportion. Therefore, the impact of feature proportion, which has been ignored by most existing work, should be taken into account and more study is required as to how to make feature proportion allocation benefit the performance of multi-biometric systems.
Design and simulation analysis of innerouter compound meshing silent-chain plate
Wencheng Wang,Hui Liu,Guoqing Cai,Pengcheng Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.9
This paper proposes a detailed parametric design method for a round-pin innerouter compound meshing silent-chain plate structure. A meshing design method for parameter harmonization among a silent chain, a sprocket hob, and an involute sprocket is proposed. To analyze the influence of extended arc parameters on the meshing process and impact, the extended arc parameter extension δ and height HY are considered as variables to formulate the motion-analysis model of the chain-drive system. The results reveal that the extended arc parameters δ and HY have a significant effect on the meshing process and the meshing impact. When δ and HY are optimal, the inner-outer compound meshing process of the chaindrive system can be smoothly realized; furthermore, the meshing impact force is minimal as it is reduced by more than 25 % compared to when only the outer meshing process occurs. Thus, the chain-plate structure is optimized.
The Research on the Inventory Prediction in Supply Chain based on BP-GA Chaos Prediction Algorithm
Wencheng Liu 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.12
In the modern supply chain management, optimizing supply chain can reduce the cost of the enterprise. In the optimization of supply chain, the inventory optimization is a very important part. Through forecasting the inventory amount, we can reduce the cost of the inventory. And we also can optimize the supply chain. Because the supply chain network is complex, we use the chaos theory to study and predict the inventory. In this paper, we put forward a chaotic forecasting method which is based on the BP neural and genetic algorithm. This new method is BP-GA chaos prediction algorithm. We use the method to predict the inventory amount. The experiment shows that the method has achieved good forecasting effect.
Research on the Supply Chain Risk Assessment Based on the Improved LSSVM Algorithm
Wencheng Liu,Xianrong Zhang 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.8
In the increasingly fierce market competition, the survival environment that enterprises are facing is increasingly harsh. This makes the supply chain is facing more and more uncertainly factors gradually on the operating environment. In addition, this increases the likelihood of the risk. Therefore, the research on the supply chain risk assessment has the important practical significance. In this paper, we put forward the assessment indexes of the supply chain risk. Then, we use the improved ACO method to optimize the parameters of the LSSVM method and we propose the improved LSSVM method. After that, we use the method to assess and study the risk of the supply chain. Finally, the experiment indicates that the reliability and validity of the evaluation system.