1,721,097 research outputs found
ACTIVITY OF CHLORAMPHENICOL ACETYLTRANSFERASE OVERPRODUCED IN ESCHERICHIA-COLI WITH WILD-TYPE AND MUTANT GROEL
No full textThe homo-oligomeric protein chloramphenicol acetyltransferase (CAT) has previously been shown to interact with a chaperone GroEL in vitro, suggesting a possible involvement of GroEL in CAT assembly. CAT was overproduced to various levels in the presence and absence of GroEL overproduction, and in groEL mutants. CAT was accumulated to 9-45% of total cellular protein in a fully soluble form, without formation of inclusion bodies. In all cases even with groEL mutants, CAT specific activity was shown proportional to the amount of protein produced, indicating the formation of active trimer CAT structure does not need GroEL in Escherichia coli
Strong suppression of chloramphenicol acetyltransferase expression by inducing T7 RNA polymerase
No full textSuppression of gene expression can be used as a way to study gene regulation. Expression of chloramphenicol acetyltransferase (CAT) under E. coli promoter was inhibited by 92 % by induction of T7 RNA polymerase which transcribes from a T7 promoter opposing E. coli promoter
Vehicle Interior Noise and Vibration Reduction Using Experimental Structural Dynamics Modification
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Vibro-acoustic Analysis of Simplified Satellite Model by Using the Statistical Energy Analysis Technique
No full textIsolating Vibration of a Miniature Linear Cryogenic Cooler with a Tuned Vibration Absorber
No full textModern surveillance equipments rely on infrared(IR) sensors for detection and observation purposes. The IR sensor is connected to a miniature cryogenic cooler to maintain at the temperature as low as 77K. However, the image quality of the sensor is degraded by the transmission of vibration disturbances from the cooler. Therefore, to maintain the high image quality of the image, the compressor vibration and the force transmitted to the sensor have to be mitigated. For the compressor isolation system, this paper proposes a tuned dynamic vibration absorber with the combination of a passive isolator. A cryogenic compressor bracket and springs are designed to allow the absorber mass to mitigate the vibration jitter in the axial direction. The system design is analyzed and tested for dynamic suppression of the harmonic force at the operating frequency of the cooler
Fast learning method for back-propagation neural network by evolutionary adaptation of learning rates
No full textIn training a back-propagation neural network, the learning speed of the network is greatly affected by its learning rate. None, however, has offered a deterministic method for selecting the optimal learning rate. Some researchers have tried to find the sub-optimal learning rates using various techniques at each training step. This paper proposes a new method for selecting the sub-optimal learning rates by an evolutionary adaptation of learning rates for each layer at every training step. Simulation results show that the learning speed achieved by our method is superior to that of other adaptive selection methods
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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