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The respiratory chain of Vibrio cholerae contains three bd-type quinol oxygen reductases as well as one cbb3 oxygen reductase. The cbb3 oxygen reductase has been previously isolated and characterized, however the natural mobile electron donor(s) which shuttles electrons between the bc1 complex and the cbb3 oxygen reductase is not known. The most likely candidates are the diheme cytochrome c4 and mono-heme cytochrome c5, which have been previously shown to be present in the periplasm of aerobically grown cultures of V. cholerae. Both cytochromes c4 and c5 from V. cholerae have been cloned and expressed heterologously in E. coli. It is shown that reduced cytochrome c4 is a substrate for the purified cbb3 oxygen reductase and can support steady state oxygen reductase activity of at least 300 e−1/s. In contrast, reduced cytochrome c5 is not a good substrate for the cbb3 oxygen reductase. Surprisingly, the dependence of the oxygen reductase activity on the concentration of cytochrome c4 does not exhibit saturation. Global spectroscopic analysis of the time course of the oxidation of cytochrome c4 indicates that the apparent lack of saturation is due to the strong dependence of KM and Vmax on the concentration of oxidized cytochrome c4. Whether this is an artifact of the in vitro assay or has physiological significance remains unknown. Cyclic voltammetry was used to determine that the midpoint potentials of the two hemes in cytochrome c4 are 240 mV and 340 mV (vs SHE), similar to the electrochemical properties of other c4-type cytochromes. Genomic analysis shows a strong correlation between the presence of a c4-type cytochrome and a cbb3 oxygen reductase within the β- and γ- proteobacterial clades, suggesting that cytochrome c4 is the likely natural electron donor to the cbb3 oxygen reductases within these organisms. These would include the β-proteobacteria Neisseria meningitidis and Neisseria gonnorhoeae, in which the cbb3 oxygen reductases are the only terminal oxidases in their respiratory chains, and the γ- proteobacterium Pseudomonas stutzeri.

Quality improvement practice (QIP), as a competitive strategy, is increasingly vital for auto factories to improve the product quality and brand reputation. Quality activity on selected automotive parts among a variety of competing candidates is featured by prioritization calculation. It arouses our interest how to select the appropriate auto part to perform quality improvement action based on the collected data from the after-sale source. Managers usually select the QIP part by the rule of thumb that is based on the quantitative criterion or the subjective preference of individuals. The total quality management (TQM) philosophy requires multiple stakeholders' involvement, regarded as a multi-criteria decision making (MCDM) issue. This paper proposes a novel hybrid MCDM framework to select the best quality improvement solution combining the subjective and objective information. The rough set-based attribute reduction (RSAR) technique was employed to establish the hierarchy structure of influential criteria, and the decision information was collected with triangular fuzzy numbers (TFNs) for its vagueness and ambiguity. In addition, the novel hybrid MCDM framework integrating fuzzy DEMATEL (decision making trial and evaluation laboratory) method, the anti-entropy weighting (AEW) technique and fuzzy VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) was developed to rank the alternatives with the combined weight of criteria. The results argue that the optimal solution keeps a high conformance with Shemshadi's and Chaghooshi's methods, which is better than the existing determination. Besides, the result analysis shows the robustness and flexibility of the proposed hybrid MCDM framework.

Abstract:With the rapid depletion of natural resources and undesired environmental changes globally, more interest has been shown in the research of green supply chain practices, including end-of-life vehicle (ELV) recycling. The ELV recycling is mandatory for auto-manufacturers by legislation for the purpose of minimizing potential environmental damages. The purpose of the present research is to determine the best choice of ELV recycling service provider by employing an integrating hybrid multi-criteria decision making (MCDM) method. In this research, economic, environmental and social factors are taken into consideration. The linguistic variables and trapezoidal fuzzy numbers (TFNs) are applied into this evaluation to deal with the vague and qualitative information. With the combined weight calculation of criteria based on fuzzy aggregation and Shannon Entropy techniques, the normative multi-criteria optimization technique (FVIKOR method) is applied to explore the best solution. An application was performed based on the proposed hybrid MCDM method, and sensitivity analysis was conducted on different decision making scenarios. The present study provides a decision-making approach on ELV recycling business selection under sustainability and green philosophy with high robustness and easy implementation.