A study on microstructural and dielectric properties of Ba0.5-xZnxSr0.45Ca0.05TiO3 ceramics

Ying-Chieh Lee,Hui-Ju Hsu,I-Yu Huang,Huei-Jyun Shih,Christian Pithan 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.6

reaction process and sintered at temperatures ranging from 1150 °C to 1250 °C. The properties of these ceramics werefound to be significantly affected by variations in the Zn content. Densification of the BZSCT ceramics was observed to occurat sintering temperatures exceeding 1225 °C. Notably, the crystalline phases and dielectric properties of these ceramics werestrongly influenced by the Zn content. Three distinct secondary phases were identified in the BZSCT ceramics, includingBaZn2.03Ti3.93O10.89, Ba2ZnTi5O13 and Zn2TiO4. The addition of Zn resulted in a shift of the Curie point to lower temperatures. Specifically, with Zn substitution (up to 15 at.%), a Curie point of -60 °C was observed in the BZSCT ceramics. Theseceramics exhibited a high dielectric constant of 1035, a low dielectric loss of 0.017%, and an impressive Q value of 442 whensintered at 1225 °C. Moreover, when comparing the dielectric constants of BZSCT ceramics at 1 MHz and 1 GHz, it wasnoted that the permittivity was only slightly reduced by less than 30% at lower frequencies. In contrast, the permittivity ofBST ceramics decreased significantly, by approximately 70%, at microwave frequencies. These findings highlight the uniqueproperties and potential applications of BZSCT ceramics, particularly in microwave applications where they outperformtraditional BST ceramics.

The effect of ferulic acid ethyl ester on leptin-induced proliferation and migration of aortic smooth muscle cells

Yung-Chieh Tsai,Yen-Mei Lee,Sy-Ying Leu,Hsiao-Yen Chiang,Mao-Hsiung Yen,Pao-Yun Cheng,Chih-Hsiung Hsu 생화학분자생물학회 2015 Experimental and molecular medicine Vol.47 No.-

Leptin is a peptide hormone, which has a central role in the regulation of body weight; it also exerts many potentially atherogenic effects. Ferulic acid ethyl ester (FAEE) has been approved for antioxidant properties. The aim of this study was to investigate whether FAEE can inhibit the atherogenic effects of leptin and the possible molecular mechanism of its action. Both of cell proliferation and migration were measured when the aortic smooth muscle cell (A10 cell) treated with leptin and/or FAEE. Phosphorylated p44/42MAPK, cell cycle-regulatory protein (for example, cyclin D1, p21, p27), β-catenin and matrix metalloproteinase-9 (MMP-9) proteins levels were also measured. Results demonstrated that leptin (10, 100 ng ml−1) significantly increased the proliferation of cells and the phosphorylation of p44/42MAPK in A10 cells. The proliferative effect of leptin was significantly reduced by the pretreatment of U0126 (0.5 μM), a MEK inhibitor, in A10 cells. Meanwhile, leptin significantly increased the protein expression of cyclin D1, p21, β-catenin and decreased the expression of p27 in A10 cells. In addition, leptin (10 ng ml−1) significantly increased the migration of A10 cells and the expression of MMP-9 protein. Above effects of leptin were significantly reduced by the pretreatment of FAEE (1 and 10 μM) in A10 cells. In conclusion, FAEE exerts multiple effects on leptin-induced cell proliferation and migration, including the inhibition of p44/42MAPK phosphorylation, cell cycle-regulatory proteins and MMP-9, thereby suggesting that FAEE may be a possible therapeutic approach to the inhibition of obese vascular disease.

The Presence of Borrelia valaisiana-Related Genospecies in Ticks and a Rodent in Taiwan

Chun-Man Huang,Hsi-Chieh Wang,Ying-Chun Lin,Shih-Hui Chiu,Ying-Shun Kao,Pei-Lung Lee,Hsiu-I Wang,Ruei-Chen Hung,Huang-I Chan,Ho-Sheng Wu,Chuen-Sheue Chiang,Jung-Jung Mu 한국미생물학회 2010 The journal of microbiology Vol.48 No.6

A field survey was conducted to investigate the presence of Borrelia burgdorferi sensu lato (s.l.) in six counties of Taiwan. Spirochetes were successfully isolated from one rodent ear sample out of 485 rodent ears and 53live, fed tick (Ixodes granulatus) samples. The spirochetes were confirmed to be B. burgdorferi s.l. by real-time PCR. In addition, 23 of 113 tick samples were tested positive for Borrelia DNA according to real-time PCR. The Borrelia isolate from the rodent and the 23 Borrelia DNA samples from the ticks were identified as B. valaisiana-related genospecies by phylogenetic analysis based on flagellin gene sequences. These findings suggest that the Borrelia valaisiana-related strains are maintained in a zoonotic cycle between tick vectors and reservoir hosts in Taiwan.

Effect of water on the formation of nanostructured mesoporous titania

Yee Shin Chang,Ying-Chieh Lee,Junji Yuhara,Lap Hong Chan,Lay Gaik Teoh,Hong Ming Chen 한국물리학회 2011 Current Applied Physics Vol.11 No.3

Mesostructured titania was prepared by a sol-gel process and the main purpose of this study is to elucidate the effect of water on the crystal structure, specific surface area, pore size, and morphology of the material. We adopt the poly (alkylene oxide) triblock copolymer of F108 as a template to form mesoporous titania. The resulting mesoporous titania, calcined at 300 ℃ to remove the template, was composed of a crystalline titania matrix containing pure anatase nanocrystals and bicrystalline (anatase and rutile) nanocrystals for samples prepared with full ethanol and with an amount of water replacement,respectively, as shown by XRD, Raman and TEM investigations. The mesoporous titania was shown to have a high specific surface area of 565.4 m^2/g and the average pore diameter is 5.2 nm, with a pore volume of 0.76 cm^3/g after it is calcined at 300 ℃ with bicrystalline frameworks when the ethanol solvent is replaced with 25% water. These results show that the hydrolysis reactions have great signifi-cance, and this nanostructured material is of interest for photocatalysts, photoelectrochemical solar cells and other photonic devices.

Virtual Screening and Testing of GSK-3 Inhibitors Using Human SH-SY5Y Cells Expressing Tau Folding Reporter and Mouse Hippocampal Primary Culture under Tau Cytotoxicity

Lin Chih-Hsin,Hsieh Yu-Shao,Sun Ying-Chieh,Huang Wun-Han,Chen Shu-Ling,Weng Zheng-Kui,Lin Te-Hsien,Wu Yih-Ru,Chang Kuo-Hsuan,Huang Hei-Jen,Lee Guan-Chiun,Hsieh-Li Hsiu Mei,Lee-Chen Guey-Jen 한국응용약물학회 2023 Biomolecules & Therapeutics(구 응용약물학회지) Vol.31 No.1

Glycogen synthase kinase-3β (GSK-3β) is an important serine/threonine kinase that implicates in multiple cellular processes and links with the neurodegenerative diseases including Alzheimer’s disease (AD). In this study, structure-based virtual screening was performed to search database for compounds targeting GSK-3β from Enamine’s screening collection. Of the top-ranked compounds, 7 primary hits underwent a luminescent kinase assay and a cell assay using human neuroblastoma SH-SY5Y cells expressing Tau repeat domain (TauRD) with pro-aggregant mutation ΔK280. In the kinase assay for these 7 compounds, residual GSK-3β activities ranged from 36.1% to 90.0% were detected at the IC50 of SB-216763. In the cell assay, only compounds VB-030 and VB-037 reduced Tau aggregation in SH-SY5Y cells expressing ΔK280 TauRD-DsRed folding reporter. In SH-SY5Y cells expressing ΔK280 TauRD, neither VB-030 nor VB-037 increased expression of GSK-3α Ser21 or GSK-3β Ser9. Among extracellular signal-regulated kinase (ERK), AKT serine/threonine kinase 1 (AKT), mitogen-activated protein kinase 14 (P38) and mitogenactivated protein kinase 8 (JNK) which modulate Tau phosphorylation, VB-037 attenuated active phosphorylation of P38 Thr180/ Tyr182, whereas VB-030 had no effect on the phosphorylation status of ERK, AKT, P38 or JNK. However, both VB-030 and VB-037 reduced endogenous Tau phosphorylation at Ser202, Thr231, Ser396 and Ser404 in neuronally differentiated SH-SY5Y expressing ΔK280 TauRD. In addition, VB-030 and VB-037 further improved neuronal survival and/or neurite length and branch in mouse hippocampal primary culture under Tau cytotoxicity. Overall, through inhibiting GSK-3β kinase activity and/or p-P38 (Thr180/Tyr182), both compounds may serve as promising candidates to reduce Tau aggregation/cytotoxicity for AD treatment.

Surface roughness improvement of alumina substrates coated using aluminum nitride sol gel

Chein-Hui-Yang,Chih-Neng Yang,Ying-Chieh Lee 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.9

To improve the surface roughness of alumina substrates, the AlN precursor mixtures were coated on the alumina substrates. AlN precursor mixtures were coated on Al2O3 substrates using a sol-gel method. The AlN precursor mixtures were preparedusing urea, aluminum nitrate, sucrose and a surfactant. The effects of calcination temperature and soaking time on the phase evolution, microstructure, mechanical properties and surface roughness of the coating layer were investigated. The phase evolution, microstructure and constitution of the coating layer after calcination were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and electron spectroscopy for chemical analysis (ESCA). It was found that Al-N-O and Al2O3 phases can coexist at 1300 o C after soaking for ≤ 60 min in N2/H2 atmosphere. The adhesive strength ofcoating layer significantly increased with increasing calcination temperature. The surface roughness of Al2O3 substrates can be improved using AlN sol gel at 1300 oC. However, the surface roughness was obviously increased at 1500 o C.

Dielectric properties and microstructures of (CaxSr1-x) ZrO3 ceramics

Yu-De Li,Jian-Ming Chen,Ying-Chieh Lee 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.6

The effects of Ca/Sr ratio and the sintering temperature on the properties of (CaxSr(1-x))ZrO3 (CSZ) ceramics were investigatedin this study. CSZ ceramics were prepared using solid-state reaction process, which were sintered in air at temperaturesranging from 1350 oC to 1450 oC. Their structures were characterized by X-ray Diffraction (XRD), Scanning ElectronMicroscopy (SEM), and Transmission Electron Microscopy (TEM). The change in Ca/Sr ratio significantly affected thecrystalline phase and the dielectric properties of the (CaxSr(1-x))ZrO3 ceramics. The secondary phase, Ca0.15Zr0.85O1.85, wasobserved and increased correspondingly with the rising of sintering temperatures. In order to understand the effects ofsecondary phase on the dielectric properties of CSZ ceramics, the Ca0.15Zr0.85O1.85 phase was prepared individually using solidstatemethod. The Ca0.15Zr0.85O1.85 ceramics sintered at 1500 oC for 2 hours possessed a dielectric constant (εr) of 21.7, adielectric loss (tanδ) of 49.510−4 and an Insulation Resistance (IR) of 2.1 × 1010 Ω. The (Ca0.7Sr0.3)ZrO3 ceramics exhibited thebest dielectric properties, with a permittivity of 29, a dielectric loss (tanδ) of 2.7 × 10−4, and an Insulation Resistance (IR) of2.6 × 1012 Ω.

Thermal oxidation temperature effect on the phases and photocatalytic properties of silver-doped TiO2 thin film prepared by co-sputtering

Hui-Ru Xu,Ping-Yuan Lee,Ya-Wei Tsai,Ying-Chieh Lee 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.2

Titanium dioxide thin films with silver dopant (Ag-TiO2) were successfully prepared on glass substrates using the thermaloxidation method. Ag-doped titanium films were prepared using direct current (DC) and radio frequency (RF) magnetron cosputteringsystems. The thermal oxidation temperature and Ag content effects on the phase evolution, microstructure, andphoto catalytic activity of TiO2 film were studied. The crystalline structures and photo catalytic activity of the annealed AgdopedTiO2 films were methodically investigated using transmission electron microscopy (TEM), field emission scanningelectron microscopy (FESEM), X-ray diffraction (XRD), and ultraviolet spectrophotometry. The results exhibited that thethermal oxidation process at 550 oC clearly caused rutile phase formation in the 2.7% Ag-doped TiO2 films directly affectingthe photo catalytic activity. The Ag-doped TiO2 films showed good photo catalytic activity under UV-light radiation, with 59%methylene blue dye degradation rate.

Phase Transformation Behavior of Bi2O3-ZnO-Nb2O5 Ceramics sintered at low Temperature

Shiao Fu-Thang,Ke Han-Chou,Lee Ying-Chieh 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

To co-fire with commercial LTCC (Low Temperature Co-fired Ceramic) materials at , different contents of were added to the (BZN) ceramics. According to the test results, the cubic phase of BZN was transformed into orthorhombic in all the test materials. phase was formed in test materials with of addition. The phase transformation of cubic BZN was controlled during the synthesis process with excess ZnO content. The Cubic and orthorhombic phases of BZN could coexist and be sintered densely at .

A Neuroprotective Action of Quercetin and Apigenin through Inhibiting Aggregation of Aβ and Activation of TRKB Signaling in a Cellular Experiment

Chiu Ya-Jen,Teng Yu-Shan,Chen Chiung-Mei,Sun Ying-Chieh,Hsieh-Li Hsiu Mei,Chang Kuo-Hsuan,Lee-Chen Guey-Jen 한국응용약물학회 2023 Biomolecules & Therapeutics(구 응용약물학회지) Vol.31 No.3

Alzheimer’s disease (AD) is a neurodegenerative disease with progressive memory loss and the cognitive decline. AD is mainly caused by abnormal accumulation of misfolded amyloid β (Aβ), which leads to neurodegeneration via a number of possible mechanisms such as down-regulation of brain-derived neurotrophic factor-tropomyosin-related kinase B (BDNF-TRKB) signaling pathway. 7,8-Dihydroxyflavone (7,8-DHF), a TRKB agonist, has demonstrated potential to enhance BDNF-TRKB pathway in various neurodegenerative diseases. To expand the capacity of flavones as TRKB agonists, two natural flavones quercetin and apigenin, were evaluated. With tryptophan fluorescence quenching assay, we illustrated the direct interaction between quercetin/ apigenin and TRKB extracellular domain. Employing Aβ folding reporter SH-SY5Y cells, we showed that quercetin and apigenin reduced Aβ-aggregation, oxidative stress, caspase-1 and acetylcholinesterase activities, as well as improved the neurite outgrowth. Treatments with quercetin and apigenin increased TRKB Tyr516 and Tyr817 and downstream cAMP-response-element binding protein (CREB) Ser133 to activate transcription of BDNF and BCL2 apoptosis regulator (BCL2), as well as reduced the expression of pro-apoptotic BCL2 associated X protein (BAX). Knockdown of TRKB counteracted the improvement of neurite outgrowth by quercetin and apigenin. Our results demonstrate that quercetin and apigenin are to work likely as a direct agonist on TRKB for their neuroprotective action, strengthening the therapeutic potential of quercetin and apigenin in treating AD.