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Supervised-learning-based algorithm for color image compression
Liu, Xue-Dong,Wang, Meng-Yue,Sa, Ji-Ming Electronics and Telecommunications Research Instit 2020 ETRI Journal Vol.42 No.2
A correlation exists between luminance samples and chrominance samples of a color image. It is beneficial to exploit such interchannel redundancy for color image compression. We propose an algorithm that predicts chrominance components Cb and Cr from the luminance component Y. The prediction model is trained by supervised learning with Laplacian-regularized least squares to minimize the total prediction error. Kernel principal component analysis mapping, which reduces computational complexity, is implemented on the same point set at both the encoder and decoder to ensure that predictions are identical at both the ends without signaling extra location information. In addition, chrominance subsampling and entropy coding for model parameters are adopted to further reduce the bit rate. Finally, luminance information and model parameters are stored for image reconstruction. Experimental results show the performance superiority of the proposed algorithm over its predecessor and JPEG, and even over JPEG-XR. The compensation version with the chrominance difference of the proposed algorithm performs close to and even better than JPEG2000 in some cases.
Activin pathway enhances colorectal cancer stem cell self-renew and tumor progression
Liu, Rui,Wang, Jun-Hua,Xu, Chengxiong,Sun, Bo,Kang, Sa-Ouk Elsevier 2016 Biochemical and biophysical research communication Vol.479 No.4
<P><B>Abstract</B></P> <P>Activin belongs to transforming growth factor (TGF)-β super family of growth and differentiation factors and activin pathway participated in broad range of cell process. Studies elaborated activin pathway maintain pluripotency in human stem cells and suggest that the function of activin/nodal signaling in self-renew would be conserved across embryonic and adult stem cells. In this study, we tried to determine the effect of activin signaling pathway in regulation of cancer stem cells as a potential target for cancer therapy in clinical trials. A population of colorectal cancer cells was selected by the treatment of activin A. This population of cell possessed stem cell character with sphere formation ability. We demonstrated activin pathway enhanced the colorectal cancer stem cells self-renew and contribute to colorectal cancer progression in vivo. Targeting activin pathway potentially provide effective strategy for colorectal cancer therapy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Activin pathway contributes to maintain colorectal cancer stem cells. </LI> <LI> Activin pathway inhibition suppresses colorectal cancer stem cell tumor formation. </LI> <LI> SB431542 inhibit tumor formation in vivo by blocking activin receptor. </LI> </UL> </P>
Experimental Study on the Monotonic and Cyclic Behavior of Carbonate Sand in the South China Sea
Xin Liu,Sa Li,Lan Lin,Tingting Li,Jiangsong Yin 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.9
Carbonate soils have specific properties that differ from those of siliceous sand. The monotonic and cyclic behavior of carbonate sand from Jinqing Island in the South China Sea was examined by undrained monotonic and cyclic simple shear tests in this paper. The monotonic test results show that the phase transformation state friction angle is 25.7o, and the critical state friction angle decreases from 38.7o to 37.3o due to particle crushing. By comparing the experimental data from the monotonic and cyclic tests, we found that the trend of the peak shear stress ratio with shear strain in each cycle of cyclic tests was close to that of monotonic tests. If the cyclic stress ratio of symmetrical cyclic tests is normalized with the phase transformation strengths obtained by the corresponding monotonic tests, it has a good relationship with the number of cycles at failure and is not affected by the relative density and vertical consolidation stress. The effects of the relative density, vertical consolidation stress and initial static shear stress on the undrained cyclic strength are discussed. Finally, a comparison of the undrained cyclic strength of carbonate sand from different regions shows that different carbonate sands have almost identical undrained cyclic strength under the medium dense state, but significant quantitative differences are observed between these carbonate sands under the dense state.
STABILITY ANALYSIS OF AN HIV PATHOGENESIS MODEL WITH SATURATING INFECTION RATE AND TIME DELAY
Maoxin Liao,Sa Zhao,Manting Liu 한국전산응용수학회 2014 Journal of applied mathematics & informatics Vol.32 No.3
In this paper, a mathematical model for HIV infection with saturating infection rate and time delay is established. By some analytical skills, we study the global asymptotical stability of the viral free equilibrium of the model, and obtain the sufficient conditions for the local asymptotical stability of the other two infection equilibria. Finally, some related numerical simulations are also presented to verify our results.
Study on the Hydrothermal Synthesis and Optical Properties of YVO4:Dy3+ Phosphor Powders
Hong-Tao Liu,Yan Liang,Xiao-Yong Gao,Sa Zhang,Xian-Wei Zhao,Xian-Mei Chen 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.8
YVO4:Dy3+ phosphor powders were synthesized by using the hydrothermal method under differentpH conditions. The crystallization, surface morphology, lattice vibration, optical properties,luminescent mechanism and influencing factors of the obtained YVO4:Dy3+ phosphor powders werecarefully studied and analyzed in detail. All of the YVO4:Dy3+ phosphor powders had tetragonalstructures, and the pH value had a significant impact on the surface morphology, structure andoptical properties of the synthesized samples. Strong acidic and alkali environments were favorablefor the crystallization of YVO4:Dy3+phosphor powders, and the YVO4:Dy3+ phosphor powderssynthesized under strong alkali environments had the best luminescent properties.
STABILITY ANALYSIS OF AN HIV PATHOGENESIS MODEL WITH SATURATING INFECTION RATE AND TIME DELAY
Liao, Maoxin,Zhao, Sa,Liu, Manting The Korean Society for Computational and Applied M 2014 Journal of applied mathematics & informatics Vol.32 No.3
In this paper, a mathematical model for HIV infection with saturating infection rate and time delay is established. By some analytical skills, we study the global asymptotical stability of the viral free equilibrium of the model, and obtain the sufficient conditions for the local asymptotical stability of the other two infection equilibria. Finally, some related numerical simulations are also presented to verify our results.
Pharmacogenomic landscape of patient-derived tumor cells informs precision oncology therapy
Lee, Jin-Ku,Liu, Zhaoqi,Sa, Jason K.,Shin, Sang,Wang, Jiguang,Bordyuh, Mykola,Cho, Hee Jin,Elliott, Oliver,Chu, Timothy,Choi, Seung Won,Rosenbloom, Daniel I. S.,Lee, In-Hee,Shin, Yong Jae,Kang, Hyun J Nature Pub. Co 2018 Nature genetics Vol.50 No.10
Spatiotemporal genomic architecture informs precision oncology in glioblastoma
Lee, Jin-Ku,Wang, Jiguang,Sa, Jason K,Ladewig, Erik,Lee, Hae-Ock,Lee, In-Hee,Kang, Hyun Ju,Rosenbloom, Daniel S,Camara, Pablo G,Liu, Zhaoqi,van Nieuwenhuizen, Patrick,Jung, Sang Won,Choi, Seung Won,Ki Nature Pub. Co 2017 Nature genetics Vol.49 No.4
<P>Precision medicine in cancer proposes that genomic characterization of tumors can inform personalized targeted therapies1-5. However, this proposition is complicated by spatial and temporal heterogeneity6-14. Here we study genomic and expression profiles across 127 multisector or longitudinal specimens from 52 individuals with glioblastoma (GBM). Using bulk and single-cell data, we find that samples from the same tumor mass share genomic and expression signatures, whereas geographically separated, multifocal tumors and/or long-term recurrent tumors are seeded from different clones. Chemical screening of patient-derived glioma cells (PDCs) shows that therapeutic response is associated with genetic similarity, and multifocal tumors that are enriched with PIK3CA mutations have a heterogeneous drug-response pattern. We show that targeting truncal events is more efficacious than targeting private events in reducing the tumor burden. In summary, this work demonstrates that evolutionary inference from integrated genomic analysis in multisector biopsies can inform targeted therapeutic interventions for patients with GBM.</P>
Lee, Sang-Yoon,Kim, Bo-Kyung,Yoon, Sa-Rah,Kim, Yeon-Joo,Liu, Tian,Woo, Joo-Hong,Chwae, Yong-Joon,Joe, Eun-Hye,Jou, Il-O Korean Society for Biochemistry and Molecular Bion 2010 Experimental and molecular medicine Vol.42 No.9
In brain tissue, astrocytes play defensive roles in central nervous system integrity by mediating immune responses against pathological conditions. Type I phosphatidylinositol 4-phosphate 5-kinase ${\alpha}$ ($PIP5K{\alpha}$) that is responsible for production of phosphatidylinositol 4,5-bisphosphate ($PI[4,5]P_2$) regulates many important cell functions at the cell surface. Here, we have examined whether $PIP5K{\alpha}$ is associated with astrocyte inflammatory responses. Gangliosides are releasable from damaged cell membranes of neurons and capable of inducing inflammatory responses. We found that treatment of primary cultured astrocytes with gangliosides significantly enhanced $PIP5K{\alpha}$ mRNA and protein expression levels. $PI(4,5)P_2$ imaging using a fluorescent tubby (R332H) expression as a $PI(4,5)P_2$-specific probe showed that ganglioside treatment increased $PI(4,5)P_2$ level. Interestingly, microRNA-based $PIP5K{\alpha}$ knockdown strongly reduced ganglioside-induced transcription of proinflammatory cytokines IL-$1{\beta}$ and $TNF{\alpha}$. $PIP5K{\alpha}$ knockdown also suppressed ganglioside-induced phosphorylation and nuclear translocation of NF-${\kappa}B$ and the degradation of $l{\kappa}B-{\alpha}$, indicating that $PIP5K{\alpha}$ knockdown interfered with the ganglioside-activated NF-${\kappa}B$ signaling. Together, these results suggest that $PIP5K{\alpha}$ is a novel inflammatory mediator that undergoes upregulation and contributes to immune responses by facilitating NF-${\kappa}B$ activation in ganglioside-stimulated astrocytes.
아드만탄 기반의 새로운 설포네이트 폴리카보네이트 난연제 성능 연구
Jian Wei Guo,Yue Qin Wang,Li Juan Feng,Xing Zhong,Chu Fen Yang,Sa Liu,Ying De Cui 한국고분자학회 2013 폴리머 Vol.37 No.4
A novel sulfonate flame retardant, 1,3,5,7-tetrakis(phenyl-4-sodium sulfonate)adamantane (FR-A), was suc-cessfully synthesized from l-bromoadamantane in sequential four-step reactions involving Fiedel-Crafts phenylation, sul-phonation, hydrolysis, and neutralization. The success of synthesis was confirmed by FTIR spectra, ‘H NMR spectra, elemental analyses and mass spectra. The effect of FR-A on the flame retardacy of polycarbonate (PC) has been studied. Limiting oxygen index (LOI) and thermogravimetric analysis (TGA) showed that this novel sulfonate flame retardant had effective flame retardancy on polycarbonate (PC). With a small amount (0.08 Wt%) of FR-A. the flame retardancy of PC was improved obviously, which got to UL 94 V-0 rating. TGA and DTA curves demonstrated that the additive raised the degradation rate of PC by promoting the quick formation of an insulating carbon layer on the surface, and confirmed that the flame retardant mechanism of PC/FR-A system was similar to potassium diphenylsulfone sulfonate (KSS).