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.

Experimental Study and Numerical Simulation of Precast Shear Wall with Rabbet-Unbonded Horizontal Connection

Chong-fang Sun,Shu-ting Liang,Xiao-jun Zhu,Hu Li,Jian-min Guo,Gang Li,Ya-min Song,Dong-yue Wu 한국콘크리트학회 2020 International Journal of Concrete Structures and M Vol.14 No.1

This paper reports the results of a seismic performance study of a precast shear wall with a new horizontal connection. The new connection is the rabbet-unbonded horizontal connection, which is composed of rabbets and unbonded rebar segments. The rabbets are used to improve the shear capacity and prevent slippage of the connection, and the unbonded rebar segments are used to improve the ductility and energy dissipation. Three specimens were tested with different parameters under cyclic quasi-static loading. The test results showed that the specimen with a larger unbonded level had a richer hysteresis curve, larger ductility, larger energy dissipation, and slightly smaller bearing capacity. Moreover, in relation to the stiffness degradation, in the initial stage, the specimen with a larger unbonded level had a smaller stiffness, whereas in the last stage, the stiffnesses were similar regardless of the unbonded level. A parameter analysis using a finite element model proved that the ductility and energy dissipation of a shear wall with the rabbet-unbonded horizontal connection increased with the unbonded length and level. In addition, when the axial compression ratio increased, the bearing capacity increased, but the load-displacement curves decreased more rapidly. It was concluded that the unbonded length and unbonded level could effectively improve the ductility and energy dissipation of a shear wall. However, they should not be too large under high pressure, and the design suggestions for the new connection need further research considering other factors.

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.

Relationships between Methionine Supply, Nitrogen Retention and Plasma Insulin-like Growth Factor-I in Growing Sheep Nourished by Total Intragastric Infusions

Li, Chong,Zhao, Guangyong Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.10

Four 4-month old Charolais${\times}$Dorset male sheep (initial liveweight $25.0{\pm}1.1\;kg$), fitted with rumen and abomasal fistulas and nourished by total intragastric infusions, were used to study the relationships between methionine (Met) supply, nitrogen (N) retention and plasma insulin-like growth factor-I (IGF-I). Four graded levels of Met, i.e. 0 g/16 g N, 1.76 g/16 g N, 3.52 g/16 g N and 7.04 g/16 g N, were infused into abomasums as experimental treatments. The sheep and treatments were allocated in a $4{\times}3$ incomplete Latin square design (Yudon square design). The experiment lasted 3 periods and each period was 10 days. Quadratic correlations were found between Met level (x, g/16 g N) and N retention (y, g/d): y = $-0.03x^2$+0.41x+2.62, $r^2$ = 0.66, n = 12, p = 0.008, and between methionine level (x, g/16 g N) and plasma IGF-I concentration (y, ng/ml): y = $0.80x^2$-4.53x+190.24, $r^2$ = 0.51, n = 12, p = 0.009. No significant correlation was found between plasma IGF-I (x, ng/ml) and N retention (y, g/d) (p>0.05). It was concluded that Met level had a significant influence on N retention and plasma IGF-I concentration whereas IGF-I might not be an important mediator in the regulation of N metabolism by Met in growing sheep nourished by total intragastric infusions.

A comprehensive analysis and comparison between vacuum and electric oven drying methods on Chinese saffron (Crocus sativus L.)

Chong Yao,Xiao-Dong Qian,Gui-Fen Zhou,Shu-Wei Zhang,Li-Qin Li,Qiaosheng Guo 한국식품과학회 2019 Food Science and Biotechnology Vol.28 No.2

The red stigmas of saffron are one of the mostexpensive spices in the world and serve as a traditionalChinese medicine. More saffron has been cultivated inChina, and different drying technologies have been studied. However, a comprehensive and comparative analysis ofdifferent drying approaches has not been well studied. Inthis study, we compared electric oven and vacuum ovendrying approaches on saffron. We found saffron was driedquicker under high vacuum drying mode with high temperatureand the quicker drying rate provided, the moreopen microstructural interstices on the saffron surface. Both methods were best fit to Midilli and Kucuk model. Besides, the coloring, aroma and bitterness strength afterdrying showed the similar results. In sum, our data suggestedthe optimal drying temperature was 100 C for20 min for two evaluated methods, however consideringthe machine cost, the electric oven drying would be the firstchoice.

De novo assembly, characterization and annotation for the transcriptome of Sphaeroma terebrans and microsatellite marker discovery

Chong Han,Qiang Li,Xiufeng Li,Zhipeng Zhang,Jianrong Huang 한국유전학회 2018 Genes & Genomics Vol.40 No.2

Sphaeroma terebrans, an economically and ecologically important marine wood-boring isopod, is mainly distributed in tropical and subtropical mangroves. Nevertheless, available genomic and transcriptomic information for this isopod is extremely deficient. Here, we first performed the assembly of S. terebrans transcriptome by Illumina sequencing. A total of 51,092 high-quality unigenes with an average length of 641 bp were obtained and 19,915 unigenes were successfully annotated in four public databases. Only 9932 out of 19915 unigenes were commonly annotated by all four databases. In addition, 9609 unigenes were categorized into 54 function categories of Gene Ontology (GO), and 14,512 unigenes were successfully grouped into 25 functional categories of the EuKaryotic Orthologous Groups (KOG) database. Moreover, 11,507 unigenes were assigned to 228 pathways of the Kyoto Encyclopedia of Genes and Genomes (KEGG). Out of 51,092 unigenes, a total of 4257 different microsatellites with motifs range from di- to hexanucleotide were identified from 3324 unigene sequences. Among 64 primer pairs selected for validation, 35 were successful in PCR amplification and 13 exhibited obvious repeat polymorphisms in the wild population of S. terebrans in Dongzhaigang (Hainan Island). The transcriptome dataset and the identified microsatellite markers (SSRs) will provide abundant information for researches on the discovery of new genes, metabolic mechanism and genetic diversity of S. terebrans.