TSSG growth, morphology and properties of potassium lithium niobate (KLN) crystals

Chong, Tow-Chong,Xu, Xue-Wu,Li, Lian,Zhang, Guang-Yu,Kumagai, H.,Hirano, M. The Korea Association of Crystal Growth 1999 한국결정성장학회지 Vol.9 No.4

In the present paper, potassium lithium niobate(KLN) crystals have been grown along <001>, <100> and <110> directions by the top seeded solution growth (TSSG) method from Li-richer melts with different compositions. The morphologies of KLN crystals grown along different directions have been studied, and the well-developed facets have been unambiguously indexed using X-ray goniometer and stereographic projection analysis. The growth mechanism and defects such as cracks and inclusions were discussed on the basis of observations of facets on the crystal-solution interfaces. The crystal compositions were determined by a chemical analysis method. The structure and lattice constants of KLN crystals were determined and calculated on the basis of XRD data by using TREOR90 and PIRUM programs. The Curie temperature and optical absorption were determined by dielectric constant peak and spectrum measurements. respectively. The blue second harmonic generation (SHG) characteristics of KLN sample were also investigated using a pulsed dye laser.

수지상세포의 방사선 저항성에 대한 연구

김은실,김종순,이명호,범희승,민정준,정환정,김성민,허영준,송호천,이제중 대한핵의학회 2003 핵의학 분자영상 Vol.37 No.3

목적 : 림프구와 비교되는 수지상 세포의 방사선 민감성을 보기 위하여 본 연구를 시행하였다. 대상 및 방법 : 말초혈액에서 분리한 T 림프구에 0 Gy, 10 Gy, 30 Gy의 방사선을 조사하고 4시간 후에 유세포 분석기를 이용하여 선량별 세포고사 빈도를 관찰하였다. 또한 조혈모세포에서 미성숙 및 성숙 수지상 세포를 단계적으로 분리 배양하여 각각 0 Gy, 10 Gy, 30 Gy, 100 Gy의 방사선을 조사하고 4시간, 24시간 그리고 48 시간 후에 선량별 세포고사 빈도를 관찰하였다. 사이토스핀(cytospin)슬라이드에 림프구와 미성숙 및 성숙 수지상세포를 3×104개 씩 분주하고 May Grunwald-Giemsa 염색한 후, 광학 현미경 하에서 각각의 세포군 당 100개의 세포에서 세포 면적당 핵의 면적 비를 측정하였다. 결과 : 림프구에서는 방사선조사 선량별로 세포고사 빈도가 유의하게 증가하였으나, 수지상 세포에서는 그 분화정도나 방사선조사 선량에 따른 세포고사의 빈도차이가 없었다. 또한 수지상 세포는 방사선선량과 관계없이 용량에 의존적으로 강력한 T-세포 자극능을 보였다. 림프구의 세포에 대한 핵의 면적 비는 미성숙 및 성숙 수지상세포의 세포에 대한 핵의 면적 비보다 현저히 큰 반면, 두 가지 수지상세포간에 유의한 차이는 없었다. 결론 : 수지상세포는 그 분화도와 상관없이 림프구에 비하여 방사선 저항성을 나타내었고, 이는 세포의 형태적 차이에 따른 표적의 크기와 관련이 있을 것으로 생각되며, 향후 분자 생물학적인 연구의 기초 자료로 활용할 수 있을 것으로 생각된다. Purpose : To evaluate radiation sensitivity of dendritic cells in comparison with lymphocytes. Materials and methods : T lymphocytes captured from peripheral blood were irradiated by 0 Gy, 10 Gy, 30Gy. Apoptosis was measured by flowcytometry for staining of Annexin V 4 hours after irradiation. Immature and mature dendritic cells processed from blood hematopoietic stern cell were irradiated by 0 Gy, 10 Gy, 30 Gy, 100 Gy respectively and apoptosis was measured by flowcytometry with time difference as 4h, 24h and 48h after irradiation. Morphometric analysis by percent nucleus was measured in three cell groups, also. Results : Lymphocytes showed radiation sensitivity by increasing apoptotic fraction according to radiation dose. However, both mature and immature dendritic cells showed consistent fraction of apoptosis in spite of increasing radiation dose. Percent nucleus ratio is significantly higher in lymphocytes than that of mature or immature dendritic cells. Stimulation of T-cell by dendritic cells was not changed after irradiation. Conclusion : Dendritic cells showed radioresistance which was associated with small size of nucleus in comparison with lymphocytes and this result would be used as a basal data of radio-labelling for the cellular trafficking studies in nuclear medicine fields.

Enhancing the CO₂ separation performance of polymer membranes via the incorporation of amine-functionalized HKUST-1 nanocrystals

Chuah, Chong Yang,Li, Wen,Samarasinghe, S.A.S.C.,Sethunga, G.S.M.D.P.,Bae, Tae-Hyun Elsevier 2019 Microporous and mesoporous materials Vol.290 No.-

<P><B>Abstract</B></P> <P>HKUST-1 nanocrystals with large accessible surface areas and high porosity were functionalized with amine groups and incorporated into polymer matrices to form mixed-matrix membranes for application in CO<SUB>2</SUB> capture. This gas permeation study reveals that pristine HKUST-1 nanocrystals are able to increase the gas permeabilities of polymer membranes with no noticeable effect on CO<SUB>2</SUB>/N<SUB>2</SUB> selectivity as a result of their high porosity and large pore dimensions. Contrarily, 20 wt% amine-functionalized HKUST-1 can improve the CO<SUB>2</SUB>/N<SUB>2</SUB> selectivity of polymer membranes by as much as 38%. As shown in a detailed analysis of the diffusivity-solubility, the amine-functionalized HKUST-1 suppressed N<SUB>2</SUB> solubility and diffusivity but enhanced CO<SUB>2</SUB> diffusivity. This resulted in an increased CO<SUB>2</SUB>/N<SUB>2</SUB> perm-selectivity. Meanwhile, the pristine HKUST-1 nanocrystals increased the diffusivity and solubility of both species in a non-selective manner. These results indicate the feasibility of tuning the CO<SUB>2</SUB> separation performance of mixed-matrix membranes by introducing amine functionality into the filler.</P> <P><B>Highlights</B></P> <P> <UL> <LI> HKUST-1 and amine-functionalized HKUST-1 nanocrystals were successfully synthesized. </LI> <LI> HKUST-1 nanocrystals improved CO<SUB>2</SUB> permeability with no effect on CO<SUB>2</SUB> selectivity. </LI> <LI> Amine-functionalized HKUST-1 enhanced CO<SUB>2</SUB>/N<SUB>2</SUB> selectivity and CO<SUB>2</SUB> permeability. </LI> <LI> Amine-functionalized HKUST-1 suppressed N<SUB>2</SUB> solubility and diffusivity substantially. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

KLF4 suppresses the tumor activity of cutaneous squamous cell carcinoma (SCC) cells via the regulation of SMAD signaling and SOX2 expression

Li, Xue Mei,Kim, Soo Jung,Hong, Dong-Kyun,Jung, Kyoung Eun,Choi, Chong Won,Seo, Young-Joon,Lee, Jeung-Hoon,Lee, Young,Kim, Chang-Deok Elsevier 2019 Biochemical and biophysical research communication Vol.516 No.4

<P><B>Abstract</B></P> <P>Kruppel-like factor 4 (KLF4) is a zinc-finger transcription factor that plays a role in terminal differentiation of epidermal keratinocytes. There are conflicting reports regarding the role of KLF4 in tumor development, with both the tumor suppressive and/or oncogenic properties depending on different conditions and cell types. In this study, we investigated the functional importance of KLF4 in cutaneous squamous cell carcinoma (SCC). Immunohistochemistry showed that KLF4 expression was relatively low in SCC lesion compared to normal epidermis. To examine the effects of KFL4, we transduced SCC lines (SCC12 and SCC13 cells) with the KLF4-expressing recombinant adenovirus. Overexpression of KLF4 significantly decreased cell proliferation and colony forming activity. In addition, overexpression of KLF4 markedly reduced invasive potential, along with the downregulation of epithelial-mesenchymal transition (EMT)-related molecules. In a mechanistic study, KLF4 inhibited SOX2, of which expression is critical for tumor initiation and growth of SCC. Further investigations indicated that SOX2 expression is induced by TGF-β/SMAD signaling, and that overexpression of KLF4 inhibited SMAD signaling via upregulation of SMAD7, an important inhibitory SMAD molecule. Based on these data, KLF4 plays a tumor suppressive role in cutaneous SCC cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Overexpression of KLF4 decreased the cell proliferation, colony forming activity, invasion and EMT potential in cutaneous SCC cells. </LI> <LI> Overexpression of KLF4 decreased SOX2 level via inhibition of SMAD2 phosphorylation. </LI> <LI> Overexpression of KLF4 inhibited SMAD signaling via upregualtion of SMAD7, an inhibitory SMAD molecule. </LI> </UL> </P>

RBPJ contributes to acquired docetaxel resistance in prostate cancer cells

Li Xue,Zhenlong Wang,Hecheng Li,Zhaolun Li,Qi Chen,Peng Zhang,Haiwen Chen,Ziming Wang,Tie Chong,T. Chong 대한독성 유전단백체 학회 2017 Molecular & cellular toxicology Vol.13 No.3

Our previous work has shown that depletion of recombination signal-binding protein J (RBPJ) results in reduced cell growth in prostate cancer cells. In this study, we aimed to investigate the function of RBPJ in the chemoresistance of prostate cancer. The expression of RBPJ was quantified in docetaxel-resistant and parental prostate cancer cells. Loss- and gainof- function experiments were conducted to explore the regulatory role of RBPJ in prostate cancer sensitivity to docetaxel. The pro-apoptotic effect of RBPJ silencing was checked in docetaxel-resistant prostate cancer cells. We found that docetaxel-resistant PC3-DR and DU145- DR cells expressed 3-5-fold high levels of RBPJ than parental PC3 and DU145 cells. Short hairpin RNAmediated knockdown of RBPJ inhibited cell proliferation and colony formation and reversed docetaxel resistance in docetaxel-resistant prostate cancer cells. In contrast, overexpression of RBPJ promoted cell growth, colony formation, and docetaxel resistance in parental prostate cancer cells. Downregulation of RBPJ induced apoptosis in docetaxel-resistant cells, which was accompanied by enhanced cleavage of caspase-3. In addition, RBPJ silencing or overexpression markedly modulated the expression of the Bcl-2 family members including Bcl-2, Bcl-xL, Mcl-1, Bax, and Bak. Altogether, RBPJ contributes to acquisition of docetaxel resistance in prostate cancer cells and may thus represent a potential target for overcoming chemotherapeutic resistance in this malignancy.

The microstructures and mechanical properties of ultra‑high‑strength PAN‑based carbon fibers during graphitization under a constant stretching

Chong Ye,Huang Wu,Dong Huang,Baoliu Li,Ke Shen,Jianxiao Yang,Jinshui Liu,Xuanke Li 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Commercial ultra-high-strength PAN-based carbon fibers (T1000G) were heat-treated at the temperature range of 2300– 2600 °C under a constant stretching of 600 cN. After continuous high-temperature graphitization treatment, microstructures, mechanical properties and thermal stability of the carbon fibers were investigated. The results show that the T1000G carbon fibers present the similar round shape with a smooth surface before and after graphitization, indicating the carbon fibers are fabricated by dry–wet spinning. In comparison, the commercial high-strength and high-modulus PAN-based carbon fibers (M40JB and M55JB) present elliptical shapes with ridges and grooves on the surface, indicating the carbon fibers are fabricated by wet spinning. After graphitization treatment from 2300 to 2600 °C under a constant stretching of 600 cN, the Young’s modulus of the T1000G carbon fibers increases from about 436 to 484 GPa, and their tensile strength decreases from about 5.26 to 4.45 GPa. The increase in Young’s modulus of the graphitized T1000G carbon fibers is attributed to the increase in the crystallite sizes and the preferred orientation of graphite crystallites along the fiber longitudinal direction under a constant stretching condition. In comparison with the M40JB and the M55JB carbon fibers, the graphitized T1000G carbon fibers are easier to be oxidized, which can be contributed to the formation of more micropores and defects during the graphitization process, thus leading to the decrease in the tensile strength.

Contributed Mini Review : Isoforms, structures, and functions of versatile spectraplakin MACF1

( Li Fang Hu ),( Pei Hong Su ),( Run Zhi Li ),( Chong Yin ),( Yan Zhang ),( Peng Shang ),( Tuan Min Yang ),( Ai Rong Qian ) 생화학분자생물학회(구 한국생화학분자생물학회) 2016 BMB Reports Vol.49 No.1

Spectraplakins are crucially important communicators, linking cytoskeletal components to each other and cellular junctions. Microtubule actin crosslinking factor 1 (MACF1), also known as actin crosslinking family 7 (ACF7), is a member of the spectraplakin family. It is expressed in numerous tissues and cells as one extensively studied spectraplakin. MACF1 has several isoforms with unique structures and well-known function to be able to crosslink F-actin and microtubules. MACF1 is one versatile spectraplakin with various functions in cell processes, embryo development, tissue-specific functions, and human diseases. The importance of MACF1 has become more apparent in recent years. Here, we summarize the current knowledge on the presence and function of MACF1 and provide perspectives on future research of MACF1 based on our studies and others. [BMB Reports 2016; 49(1): 37-44]

Bifurcation and chaotic vibration for an electromechanical integrated harmonic piezodrive system

Chong Li,Lizhong Xu,Jianqiao Zhang 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7

In this paper, the nonlinear coupled dynamics equations of the electromechanical integrated harmonic piezodrive system are proposed. Using these equations, the bifurcation and chaotic vibrations of the drive system are investigated. The results show that chaotic vibrations occur in the drive system under some parameters. The voltage on the piezoelectric actuator, the stiffness factor and the length of the piezoelectric actuator significantly affect the nonlinear vibrations of the drive system. The ranges for the system parameters that lead to a drive system with bad dynamics are shown. These results can be used to predict the dynamic load in a drive system and are useful for maximizing the power density of a drive system.

Isolation, Purification, and Structural Identification of an Antifungal Compound from a Trichoderma Strain

( Chong Wei Li ),( Rui Qing Song ),( Li Bin Yang ),( Xun Deng ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.8

Trichoderma strain T-33 has been demonstrated to have inhibitory effect on the fungus species Cytospora chrysosperma. Here, an active antifungal compound was obtained from Trichoderma strain T-33 extract via combined separation technologies, including organic solvent extraction, liquid chromatography, and thin-layer chromatography. The purified compound was further characterized by advanced analytical technologies to elucidate its chemical structure. Results indicated that the active antifungal compound in Trichoderma strain T-33 extract is 2,5-cyclohexadiene-1,4-dione-2,6-bis (1,1-dimethylethyl).

Genetic diversity of two Tibetan macaque (Macaca thibetana) populations from Guizhou and Yunnan in China based on mitochondrial DNA D-loop sequences

Li-Jing Zhong,Ming-Wang Zhang,Yong-Fang Yao,Qing-Yong Ni,Jun Mu,Chong-Qing Li,Huai-Liang Xu 한국유전학회 2013 Genes & Genomics Vol.35 No.2

Tibetan macaque (Macaca thibetana), an endangered species endemic to China, is categorized as a Category II species under the Chinese Wild Animal Protection Law and listed in Appendix II of the Convention on International Trade in Endangered Species. To further assess genetic diversity and population structure within this species,populations, revealing that variations occured among populations mainly. Further analysis demonstrated that significant genetic differentiation (Fst = 0.83628, P\0.01) and poor gene flow (Nm\1) had occurred among these four populations. On the phylogenetic tree and haplotype network plot, 22 haplotypes cluster together according to their geographical origins, exhibiting an obvious phylogeographic pattern. We speculate that the significant genetic differentiation among these macaque populations might result from long-term geographic barrier and human activity. In particular,Yangtze River probably play a vital role in population differentiation of Tibetan macaques. we sequenced 477 bp of mitochondrial DNA control region in 30 Tibetan macaques from the Guizhou (GZ) and Yunnan (YN) of China and conducted population genetic analysis, along with 15 previously described haplotype sequences representing 55 individuals from Sichuan (SC)and Anhui (AH). 87 polymorphic sites were detected in the alignment of 45 sequences and defined 22 haplotypes, of which 9 were newly identified. Haplotype diversity (h),nucleotide diversity (p) and average number of nucleotide differences (K) is 0.911 ± 0.015, 0.06090 ± 0.00126 and 28.32, respectively, indicating higher genetic diversity in the whole Tibetan macaque population. Analysis of molecular variance (AMOVA) partitioned the total variation into 83.63 % among populations and 16.37 % within populations, revealing that variations occured among populationsmainly. Further analysis demonstrated that significantgenetic differentiation (Fst = 0.83628, P\0.01) andpoor gene flow (Nm\1) had occurred among these fourpopulations. On the phylogenetic tree and haplotype networkplot, 22 haplotypes cluster together according to their geographicalorigins, exhibiting an obvious phylogeographicpattern. We speculate that the significant genetic differentiationamong these macaque populations might result fromlong-term geographic barrier and human activity. In particular,Yangtze River probably play a vital role in populationdifferentiation of Tibetan macaques.