. P Y U N . 2000. Lactococcus lactis subsp. lactis A164 was isolated from Kimchi (Korean traditional fermented vegetables). The bacteriocin produced by strain A164 was active against closely related lactic acid bacteria and some food-borne pathogens including Staphylococcus aureus, Listeria monocytogenes and Salmonella typhimurium. The antimicrobial spectrum was nearly identical to that of nisin. Bacteriocin activity was not destroyed by exposure to elevated temperatures at low pH values, but the activity was lost at high pH values. This bacteriocin was inactivated by pronase E and a,bchymotrypsin, but not by trypsin, pepsin, and a-amylase. Cultures of L. lactis subsp. lactis A164 maintained at a constant pH of 6Á0 exhibited maximum production of the bacteriocin. It was puri®ed to homogeneity by ammonium sulphate precipitation, sequential ion exchange chromatography, and ultra®ltration. Tricine±SDS±PAGE of puri®ed bacteriocin gave the same molecular weight of 3Á5 kDa as that of nisin. The gene encoding this bacteriocin was ampli®ed by PCR with nisin gene-speci®c primers and sequenced. It showed identical sequences to the nisin gene. These results indicate that bacteriocin produced by Lactococcus lactis A164 is a nisin-like bacteriocin.
This paper presents a systematic approach for estimating material performance and designing the mix proportion of concrete based on an application of a Bayesian method in the form of satisfaction curves. The one-parameter satisfaction curve represents a satisfaction probability for a concrete performance criterion as a function of the concrete material parameters. An analysis method for combining multiple satisfaction curves to form one unique satisfaction curve that can reduce the performance of concrete to a single evaluating value, the goodness value, is proposed as an evaluation tool for the performance-based mixture design procedure. The proposed performancebased mixture design procedure is applied to test cases to obtain a target-oriented concrete mix proportion design and to verify the validity of the proposed method. Finally, the expected performance results of a concrete mix proportion designed using performance-based mixture design are compared with results calculated using the American Concrete Institute estimation equation to check whether the method is applicable to actual construction.
Knowledge of fundamental lean construction principles and tools is often imparted through the physical playing of serious games and simulations. However, globalization and the emergence of the recent pandemic have created increasing demands for scalability, as well as for diverse player usability and remote implementation of the games. That said, there are challenges associated with transforming existing lean simulations to technology-oriented modes, such as computer-and VR-based formats. For example, while the potential of using advanced formats is promising, it is unclear if these versions offer an equivalent level of learning effectiveness as in-person play. This research reports on the development and testing of different forms of the Marshmallow Target Value Design (TVD) Simulation, including computer-and VR-based formats. Researchers administered and assessed post-simulation questionnaires, and the moderator effect of perceived usability was determined and analyzed. Results show that the computer-based format was more effective than the physical-based format for some TVD principles and that the VR-based format was more effective than the physical-based Marshmallow TVD Simulation for most TVD principles. For the computer-based format, usability moderated learning effectiveness. These results indicate that when developing a computer-based simulation, the usability of the simulation must be considered to ensure maximum effectiveness.
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