56 research outputs found
Robust Watermarking Method By Systematic Block Diffusion Using Discrete Cosine Transform
Digital watermarks have long been considered as a security feature. A watermarking method that involves the diffusion of limited watermark information into a large part of an image’s data has high robustness. The diffused information is summed up to a single component before detecting the watermark. The summing up process eliminates small noises by an averaging effect, which improves the robustness of the embedded watermark against attack. In this field, thus far, only an asymmetrical Chirp transformation with a small block size has been attempted. In this study, a new verification experiment for a large block size of 256 × 256 pixels is conducted. High robustness of the proposed method is revealed. This includes the finding that, in the case of a JPEG compression attack, the proposed system is robust even at strong compression of 1/70. As for a clipping attack, embedded watermarks can be detected with up to seven pixel clipping of an embedded image
BUCKLING OF AN ANNULAR SECTOR PLATE SUBJECTED TO IN-PLANE MOMENTS
"Buckling of an annular sector plate subjected to equal and opposite moments at the radial edges is examined. The governing differential equation of the plate is solved by a Galerkin method. Buckling moments and buckling modes are obtained for the annular sector plate with simply-supported radial edges and arbitrary boundary conditions along the circumferential edges.Numerical results are shown for various geometrical parameters and three different boundary conditions. Moreover,the buckling properties of an annular sector plate are compared with those of a rectangular plate and a circular beam.
Mitogen-Activated Protein Kinase Regulated by the CLAVATA Receptors Contributes to Shoot Apical Meristem Homeostasis
In Arabidopsis, the CLAVATA (CLV) pathway operates in the regulation of the size of the stem cell population in the shoot apical meristem (SAM). CLV3 functions as a small peptide ligand to negatively regulate the expression of the WUSCHEL (WUS) transcription factor through three major receptor kinase complexes of CLV1, CLV2-SUPPRESSOR OF LLP1-2 (SOL2)/CORYNE (CRN) and recently identified RECEPTOR-LIKE PROTEIN KINASE 2 (RPK2)/TOADSTOOL 2 (TOAD2). Aiming to understand the precise molecular details of CLV3 signaling, we investigated the contribution of phospho-signaling, potentially regulated by these kinase complexes, to the CLV pathway. We detected CLV3-triggered CLV1 phosphorylation, which is also conditioned by the rest of the CLV receptors, presumably by their direct association. Our comprehensive analysis of the activities of the respective CLV receptors on mitogen-activated protein kinases (MAPKs) suggested that the precise balanced regulation of MAPK activity by the CLV receptors is likely to be key for SAM homeostasis
Isolation and Characterization of Human Trophoblast Side-Population (SP) Cells in Primary Villous Cytotrophoblasts and HTR-8/SVneo Cell Line
Recently, numerous studies have identified that immature cell populations including stem cells and progenitor cells can be found among “side-population” (SP) cells. Although SP cells isolated from some adult tissues have been reported elsewhere, isolation and characterization of human trophoblast SP remained to be reported. In this study, HTR-8/SVneo cells and human primary villous cytotrophoblasts (vCTBs) were stained with Hoechst 33342 and SP and non-SP (NSP) fractions were isolated using a cell sorter. A small population of SP cells was identified in HTR-8/SVneo cells and in vCTBs. SP cells expressed several vCTB-specific markers and failed to express syncytiotrophoblast (STB) or extravillous cytotrophopblast (EVT)-specific differentiation markers. SP cells formed colonies and proliferated on mouse embryonic fibroblast (MEF) feeder cells or in MEF conditioned medium supplemented with heparin/FGF2, and they also showed long-term repopulating property. SP cells could differentiate into both STB and EVT cell lineages and expressed several differentiation markers. Microarray analysis revealed that IL7R and IL1R2 were exclusively expressed in SP cells and not in NSP cells. vCTB cells sorted as positive for both IL7R and IL1R2 failed to express trophoblast differentiation markers and spontaneously differentiated into both STB and EVT in basal medium. These features shown by the SP cells suggested that IL7R and IL1R2 are available as markers to detect the SP cells and that vCTB progenitor cells and trophoblast stem cells were involved in the SP cell population
- …