364 research outputs found

    MATH 111-011: Calculus I

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    Immobilization and characterization of bovine liver catalase on eggshell

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    Bovine liver catalase immobilized on eggshell particles was characterized and the reusability of the immobilized catalase was investigated in a batch type reactor. For immobilized catalase onto ground eggshell (ICATG), the optimum initial amount of catalase was 85 mg g-1 of eggshells, the optimum pH was 6.0 (75 mM citrate buffer) and the temperature was 30 °C. The Vmax and Km values of ICATG were determined as 29.1±1.2 U/mg of protein and 41.9±2.7 mM, respectively. The reusability of ICATG was tested and the remaining activity of ICATG was found to be 73 % of the initial activity after 80 cycles of batch operation. The amount of catalase bound onto the carrier was estimated by using the results of induced coupled plasma measurements. The catalytic efficiencies (kcat/Km) of free catalase and ICATG were found to be 1.4´106 and 2.8´103 dm3 s-1 mol-1, respectively. Catalase immobilization onto eggshell is economic and has good reusability. Hence, it can be concluded that eggshell is an efficient carrier for immobilizing catalase

    Slip distribution and stress changes associated with the 1999 November 12, Duzce (Turkey) earthquake (M (w)=7.1)

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    The 1999 November 12 Duzce earthquake (M (w) = 7.1) was apparently the eastward extension of the August 17, Izmit earthquake (M (w) = 7.4). The Duzce event caused heavy damage and fatalities in the cities of Duzce and Bolu. Here a finite-fault inversion method with five discrete time windows is applied to derive the co-seismic slip distribution of the Duzce earthquake. The fault plane is best modelled as a 40 x 20 km(2) plane, with a strike of 262degrees and a dip of 65degrees to the north, and that the majority of slip occurred in two distinct patches on either side of the hypocentre, implying bilateral rupture. The possible triggering of this event by the Izmit earthquake is investigated using Coulomb stress modelling of all large events since 1943 with the inclusion of secular loading. The results show that although the Duzce rupture plane was in a stress shadow prior to the Izmit earthquake, that event caused a significant Coulomb stress load, taking the Duzce fault out of the stress shadow, which probably precipitated failure. A comparison of the mapped Coulomb stress change with the inferred slip shows no correlation between the two. Finally, the stress modelling indicates that the northern branch of the North Anatolian fault zone, beneath the Sea of Marmara towards the city of Istanbul, is presently the most highly loaded segment of the North Anatolian Fault Zone

    Development of a Novel Integrated CCSD-ITARA-MARCOS Decision-Making Approach for Stackers Selection in a Logistics System

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    The main goal of this paper is to propose a Multiple-Criteria Decision-Making (MCDM) approach that will facilitate decision-making in the field of logistics—i.e., in the selection of the optimal equipment for performing a logistics activity. For defining the objective weights of the criteria, the correlation coefficient and the standard deviation (CCSD method) are applied. Furthermore, for determining the semi-objective weights of the considered criteria, the indifference threshold-based attribute ratio analysis method (ITARA) is used. In this way, by combining these two methods, the weights of the criteria are determined with a higher degree of reliability. For the final ranking of the alternatives, the measurement of alternatives and ranking according to the compromise solution method (MARCOS) is utilized. For demonstrating the applicability of the proposed approach, an illustrative case study pointing to the selection of the best manual stacker for a small warehouse is performed. The final results are compared with the ones obtained using the other proved MCDM methods that confirmed the reliability and stability of the proposed approach. The proposed integrated approach shows itself as a suitable technique for applying in the process of logistics equipment selection, because it defines the most influential criteria and the optimal choice with regard to all of them in a relatively easy and comprehensive way. Additionally, conceiving the determination of the criteria with the combination of objective and semi-objective methods enables defining the objective weights concerning the attitudes of the involved decision-makers, which finally leads to more reliable result

    Controls on methane concentration and stable isotope (δ2H-CH4 and δ13C-CH4) distributions in the water columns of the Black Sea and Cariaco Basin

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    Methane (CH4) concentration and stable isotope (δ2H-CH4 and δ13C-CH4) depth distributions show large differences in the water columns of the Earth's largest CH4-containing anoxic basins, the Black Sea and Cariaco Basin. In the deep basins, the between-basin stable isotope differences are large, 83‰ for δ2H-CH4 and 9‰ for δ13C-CH4, and the distributions are mirror images of one another. The major sink in both basins, anaerobic oxidation of CH4, results in such extensive isotope fractionation that little direct information can be obtained regarding sources. Recent measurements of natural 14C-CH4 show that the CH4 geochemistry in both basins is dominated (∼64 to 98%) by inputs of fossil (radiocarbon-free) CH4 from seafloor seeps. We derive open-system kinetic isotope effect equations and use a one-dimensional (vertical) stable isotope box model that, along with isotope budgets developed using radiocarbon, permits a quantitative treatment of the stable isotope differences. We show that two main factors control the CH4 concentration and stable isotope differences: (1) the depth distributions of the input of CH4 from seafloor seeps and (2) anaerobic oxidation of CH4 under open-system steady state conditions in the Black Sea and open-system non-steady-state conditions in the Cariaco Basin

    A novel TOPSIS–CBR goal programming approach to sustainable healthcare treatment

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    Cancer is one of the most common diseases worldwide and its treatment is a complex and time-consuming process. Specifically, prostate cancer as the most common cancer among male population has received the attentions of many researchers. Oncologists and medical physicists usually rely on their past experience and expertise to prescribe the dose plan for cancer treatment. The main objective of dose planning process is to deliver high dose to the cancerous cells and simultaneously minimize the side effects of the treatment. In this article, a novel TOPSIS case based reasoning goal-programming approach has been proposed to optimize the dose plan for prostate cancer treatment. Firstly, a hybrid retrieval process TOPSIS–CBR [technique for order preference by similarity to ideal solution (TOPSIS) and case based reasoning (CBR)] is used to capture the expertise and experience of oncologists. Thereafter, the dose plans of retrieved cases are adjusted using goal-programming mathematical model. This approach will not only help oncologists to make a better trade-off between different conflicting decision making criteria but will also deliver a high dose to the cancerous cells with minimal and necessary effect on surrounding organs at risk. The efficacy of proposed method is tested on a real data set collected from Nottingham City Hospital using leave-one-out strategy. In most of the cases treatment plans generated by the proposed method is coherent with the dose plan prescribed by an experienced oncologist or even better. Developed decision support system can assist both new and experienced oncologists in the treatment planning process

    Enzyme-Nanoporous Gold Biocomposite: Excellent Biocatalyst with Improved Biocatalytic Performance and Stability

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    Background: Applications involving biomolecules, such as enzymes, antibodies, and other proteins as well as whole cells, are often hampered by their unstable nature at extremely high temperature and in organic solvents. Methodology/Principal Findings: We constructed enzyme-NPG biocomposites by assembling various enzymes onto the surface of nanoporous gold (NPG), which showed much enhanced biocatalytic performance and stability. Various enzymes with different molecular sizes were successfully tethered onto NPG, and the loadings were 3.6, 3.1 and 0.8 mg g 21 for lipase, catalase and horseradish peroxidase, respectively. The enzyme-NPG biocomposites exhibited remarkable catalytic activities which were fully comparable to those of free enzymes. They also presented enhanced stability, with 74, 78 and 53 % of enzymatic activity retained after 20 successive batch reactions. Moreover, these novel biocomposites possessed significantly enhanced reaction durability under various thermal and in organic solvent systems. In a sample transesterification reaction, a high conversion rate was readily achieved by using the lipase-NPG biocomposite. Conclusion/Significance: These nano-biocomposite materials hold great potential in applications such as biosensing, molecular electronics, catalysis, and controlled delivery
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