Takuma Ishida

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The DnaA protein is the initiator of Escherichia coli chromosomal replication. In this study, we identify a novel DnaA-associating protein, DiaA, that is required for the timely initiation of replication during the cell cycle. DiaA promotes the growth of specific temperature-sensitive dnaA mutants and ensures stable minichromosome maintenance, whereas DiaA(More)
In Escherichia coli, the activity of ATP-bound DnaA protein in initiating chromosomal replication is negatively controlled in a replication-coordinated manner. The RIDA (regulatory inactivation of DnaA) system promotes DnaA-ATP hydrolysis to produce the inactivated form DnaA-ADP in a manner depending on the Hda protein and the DNA-loaded form of the(More)
Escherichia coli DiaA is a DnaA-binding protein that is required for the timely initiation of chromosomal replication during the cell cycle. In this study, we determined the crystal structure of DiaA at 1.8 A resolution. DiaA forms a homotetramer consisting of a symmetrical pair of homodimers. Mutational analysis revealed that the DnaA-binding activity and(More)
In this paper, a lifting implementation of variable-coefficient invertible deinterlacer with embedded motion detector is proposed. As previous works, the authors have developed invertible deinterlacing that suppresses comb-tooth artifacts caused by field interleaving for interlaced scanning video, which affect the quality of intraframe-based codec such as(More)
In this paper, a coefficient-parameter reduction method is proposed for invertible deinterlacing with variable coefficients. Invertible deinterlacing, which the authors have developed before, can be used as a preprocess of frame-based motion picture codec, such as MotionJPEG2000 (MJP2), for interlaced videos. When the conventional fieldinterleaving is used(More)
A new class of video format conversion between interlaced and progressive scan formats is discussed. It is a kind of the deinterlacing problem and is defined as follows: format conversion of an interlaced scan signal to a progressive scan signal of half the temporal sampling rate to the interlaced signal, and vice versa, under the criterion of equal(More)
Invertible deinterlacing with variable coefficients is proposed to suppress comb-tooth artifacts caused by field interleaving of interlaced scanning video. A vertical highpass filter is applied to detect moving artifacts around boundaries of moving objects. The coefficients of a deinterlacing filter is varied depending on the motion intensity so that the(More)
A new class of de-interlacing is developed for intra-frame-based motion picture coding such as Motion-JPEG2000. The proposed technique has two features: the sampling density preservation and the invertibility. Thus, the amount of de-interlaced pictures is not increased and the original pictures can perfectly be reconstructed. This technique is regarded as a(More)
Perfect reconstruction (PR) deinterlacer banks are proposed as new tools for spatio-temporal scalable video codec. The proposed systems separate a progressive video into two different progressive videos of a half frame rate and are novel from the viewpoint of filter-banks in that interlaced videos are given as intermediate data during analysis and synthesis(More)