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Dual-frequency piezoelectric micromachined ultrasound transducer based on polarization switching in ferroelectric thin films

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Microsystems & Nanoengineering 2023年第5期9卷 233-243页

作者： Jin Soo park Soo young Jung Dong Hun Kim Jung Ho park Ho won Jang Tae Geun Kim Seung-Hyub Baek Byung Chul Lee Bionics Research Center Korea Institute of Science and TechnologySeoul 02792Republic of Korea Department of Electrical Engineering Korea UniversitySeoul 02841Republic of Korea Center for Electronic Materials Korea Institute of Science and TechnologySeoul 02792Republic of Korea Department of Material Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea Division of Bio-Medical Science and Technology KIST SchoolUniversity of Science and Technology(UST)Seoul 02792Republic of Korea KHU-KIST Department of Converging Science and Technology Kyung Hee UniversitySeoul 02447Republic of Korea

Due to its additional frequency response,dual-frequency ultrasound has advantages over conventional ultrasound,which operates at a specific frequency ***,a tunable frequency from a single transducer enables sonographers to achieve ultrasound images with a large detection area and high *** facilitates the availability of more advanced techniques that simultaneously require low-and high-frequency ultrasounds,such as harmonic imaging and image-guided *** this study,we present a novel method for dual-frequency ultrasound generation from a ferroelectric piezoelectric micromachined ultrasound transducer(PMUT).Uniformly designed transducer arrays can be used for both deep low-resolution imaging and shallow high-resolution *** switch the ultrasound frequency,the only requirement is to tune a DC bias to control the polarization state of the ferroelectric *** vibration of the PMUT membrane strongly depends on the polarization state,producing low-and high-frequency ultrasounds from a single excitation *** strategy for dual-frequency ultrasounds meets the requirement for either multielectrode configurations or heterodesigned elements,which are integrated into an ***,this technique significantly reduces the design complexity of transducer arrays and their associated driving circuits.

关键词： piezoelectric ferroelectric enable

Growth and Magnetic Properties of Sol-Gel Derived Co-Doped ZnO Thin Film

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Journal of Rare Earths 2006年第Z1期24卷 59-63页

作者： young Sung Kim Ki Chul Kim won Pil Tae Dae Ho Yoon Tae Seok park Su Jeong Suh Advanced Material Process of Information Technology Sungkyunkwan University Suwon 440-746 Korea Cambridge-ETRI Joint R&D Centre Electronics and Telecommunications Research Institute Daejeon 305-350 Korea Ulsan Industry Promotion Techno Park Ulsan 683-804 Korea Advanced Material Process of Information Technology Sungkyunkwan University Suwon 440-746 Korea Advanced Material Process of Information Technology Sungkyunkwan University Suwon 440-746 Korea Advanced Material Process of Information Technology Sungkyunkwan University Suwon 440-746 Korea

Zn1-xCoxO films were grown on glass by sol-gel spin coating process. A homogeneous and stable Zn1-xCoxO sol was prepared by dissolving zinc acetate dihydrate, cobalt acetate tetrahydrate and aluminium chloride hexahydrate as solutes in solution of isopropanol and monoethanolamine. The films were postheated and vacuum annealed, and investigated for c-axis preferred orientation and electromagnetic properties. Zn1-xCoxO films with different Co concentrations were oriented well along the c-axis, especially the Zn1-xCoxO film with 10% Co(atom fraction) was highly c-axis oriented. The transmittance spectra show that Zn1-xCoxO films occur d-d transition and sp-d exchange interaction between Co2+ ions. The electrical resistivity of the films at 10% Co had the lowest value because the crystallite size became largest and the crystallinity of the c-axis was improved. X-ray photoelectron spectroscopy and alternating gradient magnetometer analyses indicated that no Co metal cluster was formed, and the ferromagnetism at room temperature appeared. The characteristics of the electrical resistivity and room temperature ferromagnetism of sol-gel derived Zn1-xCoxO films suggest a potential application of dilute magnetic semiconductor devices.

关键词： sol-gel Zn1-xCoxO thin film dilute magnetic semiconductor (DMS)

Gold nanoparticle-assisted delivery of brain-derived neurotrophic factor to cerebral organoids

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Nano Research 2022年第4期15卷 3099-3105页

作者： Sung Bum park Hye-Jin Cho Sang Rin Moon Kyoung Jin Choi won Hoon Jung Ki young Kim Byumseok Koh Therapeutics and Biotechnology Division Korea Research Institute of Chemical Technology141 Gajeong-roYuseong-guDaejeon 34114Republic of Korea Chemical Platform Technology Division Korea Research Institute of Chemical Technology141 Gajeong-roYuseong-guDaejeon 34114Republic of Korea

Gold nanoparticle(AuNP)-assisted delivery of proteins/drugs to cells or in vivo systems has long been ***,their interaction with in vivo mimicking organoids is still largely ***,we conjugated brain-derived neurotropic factor(BDNF)to the AuNP surface and monitored how AuNP-BDNF interacts with cerebral *** suggest that AuNP-BDNF can successfully enter cerebral organoids and can be found up to 15.21μm inside cerebral ***-BDNF does not induce significant cytotoxicity to cerebral organoids at concentrations up to 2 nM and increases the expression of 75 genes compared to control cerebral *** data suggest the successful delivery of BDNF through AuNP-BDNF conjugation in cerebral organoids,and the conjugation can affect its differentiation.

关键词： gold nanoparticles cerebral organoids delivery penetration differentiation viability

Gene expression analysis of primary normal human hepatocytes infected with human hepatitis B virus

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World Journal of Gastroenterology 2006年第31期12卷 4986-4995页

作者： Hyun Mi Ryu Sung Gyoo park Sung Su Yea won Hee Jang young-Il Yang Guhung Jung School of Biological SciencesSeoul National University Seoul151-742Korea School of Biological Sciences and Institute of MicrobiologySeoul National University Seoul151-742Korea The Paik-Inje Memorial Institute for Biomedical ScienceInje University Pusanjin-guPusan 614-735Korea Department of PathologyCollege of Medicine Inje UniversityPaik HospitalPusan 614-735Korea

AIM： To find the relationship between hepatitis B virus （HBV） and hepatocytes during the initial state of infection by cDNA microarray. METHODS： Primary normal human hepatocytes （PNHHs） were isolated and infected with HBV. From the PNHHs, RNA was isolated and inverted into complement DNA （cDNA） with Cy3- or Cy5- labeled dUTP for microarray analysis. The labeled cDNA was hybridized with microarray chip, including 4224 cDNAs. From the image of the microarray, expression profiles were produced and some of them were confirmed by RT-PCR, immunoblot analysis, and NF-κB luciferase reporter assay. RESULTS： From the cDNA microarray, we obtained 98 differentially regulated genes. Of the 98 genes, 53 were up regulated and 45 down regulated. Interestingly, in the up regulated genes, we found the TNF signaling pathway-related genes： LT-α, TRAF2, and NIK. By using RT-PCR, we confirmed the up-regulation of these genes in HepG2, HuhT, and Chang liver cells, which were transfected with pHBV1.2x, a plasmid encoding all HBV messages. Moreover, these three genes participated in HBV- mediated NF-κB activation. CONCLUSION： During the initial state of HBV infection, hepatocytes facilitate the activation of NF-κB through up regulation of LT-α, TRAF2, and NIK.

关键词： cDNA microarray Primary normal human hepatocytes LT-α TRAF2 NIK NF-κB

Pin1 overexpression in colorectal cancer and its correlation with aberrant β-catenin expression

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World Journal of Gastroenterology 2005年第32期11卷 5006-5009页

作者： Chang-Jae Kim Yong-Gu Cho Yong-Gyu park Suk-Woo Nam Su-young Kim Sug-Hyung Lee Nam-Jin Yoo Jung-young Lee won-Sang park young-Mok Yang Department of PathologyCollege of Medicine The Catholic University of KoreaSeoul 137-701South Korea Department of StatisticsCollege of Medicine The Catholic University of KoreaSeoul 137-701South Korea Genetic Laboratory of Premedical CourseKon-Kuk University College of Medicine Chung-JuSouth Korea

AIM： To investigate clinical significance of Pin1 and β-catenin expression in colorectal cancers and to demonstrate the relationship of their expression. METHODS： The role of Pin1 and β-catenin protein in colorectal tumorigenesis and their clinicopathologic significance were analyzed by immunohistochemistry, and correlation between Pin1 and β-catenin protein expressions was also studied in 124 patients with colorectal cancer who were surgically treated. RESULTS： Normal colonic epithelium either failed to express or showed focal and weak expression of Pin1 and β-catenin. Overexpression of Pin1 and β-catenin protein was found in 23 （18.54%） and 50 （40.3%） of 124 colorectal cancers, respectively. Overexpression of both proteins was not related to the lymph node metastasis, tumor stage and survival period after excision. Survival analysis results indicated that tumor stage was a valuable predictor of survival. Interestingly, a significant correlation was found between Pin1 and β-catenin protein expression. CONCLUSION： Overexpression of Pin1 and β-catenin may be closely related with the development and/or progression of colorectal carcinoma and further supports that Pin1 overexpression might contribute to the upregulation of β-catenin.

关键词： Pin1, Immunohistochemisty β-catenin, Survival

Effects of Nitrogen Source and Bacterial Elicitor on Isoflavone Accumulation in Root Cultures of Albizzia kalkora （Roxb.） Prain

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Journal of Integrative Plant Biology 2006年第9期48卷 1108-1114页

作者： So-young park Wi-young Lee youngki park Jin-Kwon Ahn Biotechnology Division Korea Forest Research Institute Suwon 441-350 Korea

Changes in cellular isoflavone （daidzein and genistein） contents were monitored in root cultures of Albizzia kalkora （Roxb.） Prain after feeding different ratios of NH4^＋/NO3^- and treatment with a biotic elicitor （three strains of Rhizobium sp.）. The NH4^＋/NO3^- ratio appears to be positively correlated with daidzein content in the roots and shows a negative correlation with genistein. Among the three different strains of Rhizobium used, the strain ATCC 15834 caused a 35% increase in daidzein production by infection. In the case of genistein, maximum production （94%） was obtained when cultures were treated on Day 6 by the strains ATCC 15834 and KCTC 1541. The biosynthetic pathway of the two isoflavones apparently reacts differently to the same culture conditions and the same strains of Rhizobium. Therefore, the present data suggest that the production of daidzein and genistein could be modulated by changing the NH4^＋/NO3^- ratio and the application of Rhizobium.

关键词： Albizzia kalkora infection isoflavone nitrogen root culture

Weldability evaluation and tensile strength estimation model for aluminum alloy lap joint welding using hybrid system with laser and scanner head

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中国有色金属学会会刊：英文版 2012年第S3期22卷 596-604页

作者： Dong-Yoon KIM young-Whan park Department of Mechanical Engineering Pukyong National University

Aluminum welding using a hybrid system with a laser and scanner welding head was performed under various welding conditions to verify the feasibility of applying an aluminum alloy to a car *** experimental material was 5J32 aluminum alloy,and the laser power,welding speed,and laser incidence angle were used as the control *** weld bead shape and the tensile shear strength were evaluated in order to understand the aluminum lap joint weld *** of variance (ANOVA) was conducted to identify the effect of the process variables on the tensile shear *** strength estimation models using three different regression models were also *** input variables were the laser power,welding speed,and laser incidence angle,and the output was the tensile shear *** the models,the second-order polynomial estimation model had the best estimation performance,and the average error rate of this model was 0.058.

关键词： laser welding scanner remote welding 5J32 aluminum alloy regression model

Extract from Zanthoxylum piperitum Induces Apoptosis of AGS Gastric Cancer Cells through Akt/MDM2/p53 Signaling Pathway

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Chinese Journal of Integrative Medicine 2021年第10期27卷 752-759页

作者： Ye Seul park Gun He Nam Kyung Jo Jo Hye won Kawk Sang Yung Kim young Min Kim Department of Biological science and Biotechnology College of Life science and Nano TechnologyHannam University1646 Yuseong-daeroYuseong-guDaejeon 34054South Korea Department of Food Science&Bio Technology Shinansan UniversityDeahakro Danwon-guAnsan-CityGyenggi-doKorea

Objective:To determine the effect of Zanthoxylum piperitum extracet(ZPE)on apoptosis and analyze anticancer substances in ZPE,changes in proteins related to apoptosis,and pathological changes in tumors in ***:Fifteen 4-week-old female BALB/c nu/nu mice were divided into 3 groups depending on ZPE dose,with 5 in each *** gastric carcinoma cells(1 x 10^(6) cells/200 jxL)were subcutaneously injected into the flank of each *** week after the injection of AGS cells,ZPE was administered to the skin tissue[10 or 50 mg/(kg-d)]in the low-and high-dose groups,respectively for 20 *** animals were injected with vehicle *** 3 weeks,the tumor was extracted and carried out for immunohistochemistry,the tendency of apoptosis and p53 in the body was checked using TdT-mediated dUTP nick-end labeling(TUNEL)*** 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay,annexin V dead cell staining,cell cycle arrest and Western blotting,AGS gastric carcinoma cells were incubated with various concentrations of ZPE for 24 *** survival rates were analyzed by MTT *** was analyzed using annexin V dead cell staining and cell cycle arrest and measured using Muse cell ***:High performance liquid chromatography(HPLC)analysis showed that ZPE contained organic sulfur compounds such as alliin and *** assay results revealed that ZPE(10-85»xg/mL)could effectively inhibit the growth of AGS gastric cancer cells at higher concentrations(P<0.05,P<0.01).The annexin V&dead cell staining assay and cell cycle arrest assay confirmed a dose-dependent increase in the apoptosis rate and G!phase in ZPE(10-70 jig/mL)*** decreased the expression of anti-apoptotic proteins(p-Akt,p-MDM2,Bcl-2),while increased pro-apoptotic proteins(cleaved PARP,p53,pro-Caspase 3,Bax).TUNEL assays revealed an increase in cell *** staining confirmed the involvement of ***:ZPE decreases AGS cell

关键词： AGS gastric cancer cells Zanthoxylum piperitum apoptosis Akt/MDM2/p53 signaling pathway active compounds

Influence of the h TERT rs2736100 polymorphism on telomere length in gastric cancer

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World Journal of Gastroenterology 2015年第31期21卷 9328-9336页

作者： Byung Joon Choi Jung Hwan Yoon Olga Kim won Suk Choi Suk Woo Nam Jung young Lee won Sang park Department of Pediatrics College of MedicineThe Catholic University of Korea Department of Pathology College of MedicineThe Catholic University of Korea Functional Rnomics Research Center College of MedicineThe Catholic University of Korea

AIM: To investigate the functional consequences of rs2736100 polymorphism in telomere length and examine its link to gastric cancer ***: Telomere length and human telomerase reverse transcriptase(h TERT) m RNA expression were measured in 35 gastric cancer tissues and 5 cell lines and correlated to rs2736100 polymorphism. The relationship between rs2736100 polymorphism and the risk of gastric cancer were examined in 243 gastric cancer patients and 246 healthy ***: The rs2736100 A allele carrier is closely associated with reduced h TERT m RNA expression and shortened telomere length in gastric cancer tissue and cell lines. When gastric cancers were stratified by histological subtype,telomere length and h TERT m RNA levels were significantly increased in those with the C/C genotype in intestinal-type gastric cancer,but not in diffuse-type gastric cancer. Interestingly,there was no significant difference in the genotype and allele frequencies of the rs2736100 polymorphism between the patients with gastric cancer and healthy ***: The rs2736100 polymorphism of the h TERT gene is involved in the regulation of h TERT expression and telomere length,but not in the risk of gastric cancer.

关键词： Human telomerase reverse transcriptase Telomere Ga