Browsing by Issue Date, starting with "2019-09-17"

Now showing 1 - 20 of 6857

Signal Enhancement of Silicon Nanowire Field-Effect Transistor Immunosensors by RNA Aptamer
(2019-09-17)
Vu, Cao-An
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Hu, Wen-Pin
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Yang, Yuh-Shyong
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Chan, Hardy Wai-Hong
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Chen, Wen-Yih
Silicon nanowire field-effect transistors (SiNW-FETs) have been demonstrated as a highly sensitive platform for label-free detection of a variety of biological and chemical entities. However, detecting signal from immunoassays by nanoFETs is severely hindered by the distribution of different charged groups of targeted entities, their binding orientation, and distances to the surface of the FET. Aptamers have been widely applied as a recognition element for plentiful biosensors because of small molecular sizes and moderate to high specific binding affinity with different types of molecules. In this study, we propose an effective approach to enhance the electrical responses of both direct (6x-histidine) and sandwich (amyloid beta 1-42) immunoassays in SiNW-FETs with R18, a highly negative charged RNA aptamer against rabbit immunoglobulin G (IgG). Empirical results presented that the immunosensors targeted with R18 expressed a significantly stabilized and amplified signal compared to the ones without this aptamer. The research outcome provides applicability of the highly negative charged aptamer as a bioamplifier for immunoassays by FETs.
Theoretical Study for Exploring the Diglycoside Substituent Effect on the Antioxidative Capability of Isorhamnetin Extracted from Anoectochilus roxburghii
(2019-09-17)
Nguyen Minh Thong
;
Vo, Quan V.
;
Trinh Le Huyen
;
Mai Van Bay
;
Dinh Tuan
Radical-scavenging activity of isorhamnetin (1) and its diglycosides, named isorhamnetin-3,5'-O-beta-D-diglucoside (2) and isorhamnetin-3,7-O-beta-D-diglucoside (3) extracted from Anoectochilus roxburghii, has been studied through three main antioxidant pathways: hydrogen atom transfer (HAT), single electron transfer followed by proton transfer, and sequential proton loss electron transfer (SPLET). All thermodynamic parameters related to these radical-scavenging mechanisms were computed at the B3LYP/6-311G(d,p) level of theory both in the gas phase and in solution. The results suggest that HAT is the predominant mechanism in the gas phase, while SPLET is supported in an aqueous environment. In addition, the stability of radicals has also been explored by electron spin density and intramolecular hydrogen bonding. The potential energy profiles and kinetic calculations for the reactions between the selected compounds and the CH3OO center dot radical were calculated at 298.15 K. Among all investigated, compound 2 has the highest antioxidant activity with the lowest Gibbs free energy (-4.05 kcal/mol) and the highest hydrogen atom transfer rate constant (3.61 x 10(6) M(-1)s(-1)). Substitution of the OH and OMe groups by two glucoses at the 3 and 5' sites of isorhamnetin has a significant impact on its antioxidant activity.
Stabilizing Ferroelectric Domain Switching of Hafnium Aluminum Oxide Using Metal Nitride Electrode Engineering
(2019-09-17)
Liu, Chien
;
Tung, Yi-Chun
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Tseng, Chih-Yang
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Wang, Wei-Chun
;
Chen, Hsuan-Han
In this work, we comprehensively investigated the metal-electrode stress engineering on HfAlO metal-ferroelectric-metal capacitor. According to experimental results, we confirm that high-nitrogen tantalum-nitride electrode with good chemical stability not only mitigates the anti-ferroelectric property and gate leakage current, but also improves the wake-up effect and endurance cycling characteristics, which shows the great potential for future applications of low-power ferroelectric memories. (c) 2019 The Electrochemical Society.
Effect of a-InGaZnO TFT Channel Thickness under Self-Heating Stress
(2019-09-18)
Tai, Mao-Chou
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Chang, Po-Wen
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Chang, Ting-Chang
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Tsao, Yu-Ching
;
Tsai, Yu-Lin
In this work, indium-gallium-zinc-oxide thin film transistors (IGZO-TFTs) with different channel thicknesses were compared after self-heating stress (SHS). Although TFTs with a thicker channel have higher current during stress conditions, less degradation is reported. This degradation, manifest as the threshold voltage shift in the transfer characteristics, is well described by the stretched-exponential equation. In addition, the average effective barrier height, Et, is extracted to compare the difference in degradation between both TFTs, and finds that the barrier height in the thick channel device is twice that of the thin channel device. Finally, a COMSOL simulation is performed to demonstrate the electrical difference at the gate insulator layer and confirm such phenomena. (C) 2019 The Electrochemical Society.
Pulse-Driven Nonvolatile Perovskite Memory with Photovoltaic Read-Out Characteristics
(2019-09-18)
Chang, Shu-Jui
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Chen, Syuan-Ye
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Chen, Po-Wen
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Huang, Szu-Jung
;
Tseng, Yuan-Chieh
This paper presents a unique GdFe08Ni0.2O3 perovskite thin film for use in pulse-controlled nonvolatile memory devices (combined with a SrTiO3 (STO) substrate) without the need for an electrical-stressing read-out process. The use of pulse voltage imposes permanent downward/upward polarization states on GFNO, which enables greater energy density and higher energy efficiency than the unpoled state for memory. The two polarization states produce carrier migrations in opposing directions across the GFNO/STO interface, which alter the depletion region of the device, as reflected in photovoltaic short-circuit current density (J(sc)) values. Modulating the duration (varying the number of sequential pulses but fixing the pulse width and delay time) and direction of continuous pulse voltage is an effective method for controlling J(sc), thereby allowing the fabrication of nondestructive, light-tunable, nonvolatile memory devices. In experiments, J(sc) in the downward polarized state was approximately 6 times greater than that in the upward polarized state. It is promising that more memory states can be enabled by the proposed heterostructure by selecting appropriate pulse trains. Real-time interfacial changes (relative to the nonvolatile characteristics of the device) were obtained by applying synchrotron X-ray techniques simultaneously with pulse characterization. This made it possible to separately probe the electronic and chemical states of the GFNO (a p-type-like semiconductor) and STO (an n-type-like semiconductor) while varying the pulse direction, thereby making it possible to identify the mechanisms underlying the observed phenomena.
Mean field theory of short-range order in strongly correlated low dimensional electronic systems
(2019-09-18)
Rosenstein, Baruch
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Li, Dingping
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Ma, Tianxing
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Kao, H. C.
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電子物理學系
Mean field approach, although a generally reliable tool that captures major short-range correlations, often fails in symmetric low dimensional strongly correlated electronic systems like those described by the Hubbard model. In these situations a symmetry is almost broken. The problem is linked to the restoration of the symmetry due to strong fluctuations (both quantum and thermal) on all scales. The restoration of symmetry in statistical models of scalar order parameter fields was treated recently successfully on the Gaussian approximation level by symmetrization of the correlators. Here the idea is extended to fermionic systems in which the order parameter is composite. Furthermore, the precision of the correlators can be improved perturbatively. Such a scheme (based on covariant Gaussian approximation) is demonstrated on the one dimensional (1D) and 2D one band Hubbard models by comparison of the correlator with exact diagonalization and MC simulations, respectively.
Two-gap feature in optimally electron-doped cuprates
(2019-09-19)
Hu, Wei
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Feng, Zhongpei
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Yuan, Jie
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Xiang, Tao
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Li, Dingping
The dependence of the Hall conductivity on temperature and magnetic field in optimally doped La2-xCexCuO4 +/-delta (x = 0.105) thin films demonstrates that both the hole and the electron bands undergo Cooper pairing. The magnetic field suppresses the dominant hole band pairing more effectively, making the subdominant electron band pairing visible. Positively charged Cooper pairs dominate the Hall signal in the mixed state at a weak magnetic field near T-c, while at large field the negatively charged Cooper pairs take over. Sign reversals of the Hall conductivity induced by superconducting fluctuation occur in the transition and can be explained by a weakly coupled two-band Ginzburg-Landau-Lawrence-Doniach model.
Transplant Recipients Using Tacrolimus Had Higher Utilization of Healthcare Services Than Those Receiving Cyclosporine in Taiwan
(2019-09-19)
Lin, Yi-Chang
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Tsai, Chien-Sung
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Li, I-Hsun
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Tsai, Yi-Ting
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Huang, Tien-Yu
To date, population-based studies on the healthcare service utilization among stable heart, kidney, and liver transplant recipients with different calcineurin inhibitors are still scarce. Therefore, we used the Taiwan National Health Insurance Research Database to conduct a nationwide cross-sectional study to estimate the healthcare utilization of stable transplant recipients with tacrolimus or cyclosporine (n = 3,482). The sampled patients in this study comprised 377 heart, 1,693 kidney, and 1,412 liver transplant recipients between 1 January 2011 and 31 December 2011. Each subject was followed for a 1-year period to evaluate his/her healthcare service utilization. Outcome variables of the healthcare service utilization were stated as below: numbers of outpatient visits, outpatient costs, numbers of inpatient days, inpatients costs, and total costs of all healthcare services. As for all healthcare service utilization, stable transplant recipients on tacrolimus had significantly more outpatient visits (40.7 vs. 38.6), outpatient costs (US$10,383 vs. US$8,155), and total costs (US$12,516 vs. US$10,372) of all healthcare services than those on cyclosporine during the 1-year follow-up period. Additionally, further analysis showed that heart transplant recipients receiving tacrolimus incurred 1.7-fold higher inpatient costs compared to patients receiving cyclosporine. We concluded that transplant recipients using tacrolimus had significantly higher utilization of all healthcare services than those receiving cyclosporine as immunosuppressive therapy.
Controlling the electrostatic interaction using a thermal signal to structurally change thermoresponsive nanoparticles
(2019-09-20)
Akimoto, Jun
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Lin, Hsiu-Pen
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Li, Yaw-Kuen
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Ito, Yoshihiro
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應用化學系
The negatively charged thermoresponsive polymers poly(benzyl methacrylate)-b-poly(acrylic acid)-b-poly(N-isopropylacrylamide) (PBzMA-b-PAAc-b-PIPAAm) were prepared by reversible-addition fragmentation chain transfer polymerization. The polymer formed core-shell polymeric micelles possessing a thermoresponsive corona composed of PAAc-b-PIPAAm below the lower critical solution temperature (LCST) of the PIPAAm chain. The nonionic thermoresponsive polymeric micelle composed of PBzMA-b-PIPAAm exhibited extensive intermicellar aggregation after the hydrophobic phase transition of the corona-forming PIPAAm chains. In contrast, insertion of the PAAc chain into the thermoresponsive micelle maintained its dispersibility above the LCST of PIPAAm because of the electrostatic repulsion between the micelles. The micelles with short PAAc chains suppressed the effect of the negative charge derived from PAAc below the LCST because of the extended PIPAAm chain on the micellar surface. In contrast, the negative charge property appeared due to collapse of the PIPAAm layer above the LCST. This thermoresponsive change in its electrostatic behavior enables the micelle to control the adsorption and desorption of oppositely charged molecules in response to the temperature change across the LCST.
Electrochemically active novel amorphous carbon (a-C)/Cu3P peapod nanowires by low-temperature chemical vapor phosphorization reaction as high efficient electrocatalysts for hydrogen evolution reaction
(2019-09-20)
Manikandan, Arumugam
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Sriram, Pavithra
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Hsu, Kun-Chieh
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Wang, Yi-Chung
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Chen, Chia-Wei
Toward finding low-cost electrocatalysts with high catalytic properties to replace noble metals as high efficient electrocatalysts in electrochemical hydrogen evolution reaction (HER) of total water splitting plays a vital role to approach the green and sustainable energy supply. Here, we demonstrate the direct growth of novel copper phosphide coated with amorphous carbon, namely heterostructured a-C/Cu3P peapod nanowires from chemically synthesized copper nanowires (Cu NWs) followed by a chemical vapor phosphorization reaction (CVPR) process at a low temperature of 400 degrees C. The heterostructured a-C/Cu3P peapod nanowires exhibit a superior electrocatalytic activity by a lower overpotential of 287 mV at a current density of 10 mA cm(-2) with a low Tafel slope of 72 mV dec(-1) and excellent stability over 1000 cycles. The superior electrocatalytic performance can be explained by the superior contact of the electrolyte with active sites on the heterostructured a-C/Cu3P due to the high surface area of peapod nanowire structure covered by defective edges of graphene with the encapsulated amorphous carbon layer, which can tremendously enhance electrical conductivity at the surface. (C) 2019 Published by Elsevier Ltd.
活化教育專業知識之教學實踐研究計畫
(2019-09-20)
陳鏗任
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國立交通大學教育研究所
本計畫以兩學期的時間，考慮不同課程特性與過去兩年教學所遇之挑戰，活化教學策略，精進教育類課程的學習體驗，以達到活化師資培育教學的創新目標：1. 教育基礎課程（教育哲學）：導入學思達教學法培養師資生批判思考與表達自身教育理念，輔以數位閃示卡之使用強化師資生知識基礎。2. 教師專業課程（教育研究法、教育統計學）：運用翻轉教室，將研究所層級的方法基礎課程融入實務元素。3. 教育方法課程（學習與閱讀理解策略、差異化教學）：以小組合作與展演，輔以同儕回饋，培養師資生應用多元教學方法與學習策略之技能。計畫主持人共完成54之教學影片、在五門課程中導入四種創新教法，並於報告末提出五個重要的教學設計原則，提供未來教授教育學科的教師參考。應用此五項原則，可以有效活化教育專業知識，讓學理貼近專業實務。
A quadrupole ion trap mass spectrometer for dry microparticle analysis
(2019-09-21)
Ozdemir, Abdil
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Lin, Jung-Lee
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Gulfen, Mustafa
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Hsiao, Chun-Jen
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Chen, Chung-Hsuan
In this work, we report a new design of a charge detection quadrupole ion trap mass spectrometer (QIT-MS) for the analysis of micro-sized dry inorganic and bioparticles including red blood cells (RBCs) and different sizes of MCF-7 breast cancer cells. The developed method is one of the fastest methods to measure the mass of micro-sized particles. This system allows the online analysis of various micro-sized particles up to 1 x 10(17) Da. The calibration of the mass spectrometer has been done by using different sizes of polystyrene (PS) particles (2-15 mu m). The measured masses of RBCs were around 1.8 x 10(13) Da and MCF-7 cancer cells were between 1 x 10(14) and 4 x 10(14) Da. The calculated mass distribution profiles of the particles and cells were given as histogram profiles. The statistical data were summarized after Gaussian type fitting to the experimental histogram profiles. The new method gives very promising results for the analysis of particles and has very broad application.
Tailoring fluorescence emissions, quantum yields, and white light emitting from nitrogen-doped graphene and carbon nitride quantum dots
(2019-09-21)
Gu, Siyong
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Hsieh, Chien-Te
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Gandomi, Yasser Ashraf
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Li, Jianlin
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Yue, Xing Xing
Highly fluorescent N-doped graphene quantum dots (NGQDs) and graphitic carbon nitride quantum dots (CNQDs, g-C3N4) were synthesized using a solid-phase microwave-assisted (SPMA) technique. The SPMA method, based on the pyrolysis of citric acid and urea with different recipes, is capable of producing quantum dots with coexisting NGQDs and CNQDs at 280 degrees C within only five minutes. The photoluminescence (PL) emissions from NGQD and CNQDs are strongly dependent on the excitation wavelength and the solvent type, i.e., water, ethanol, and N-methyl pyrrolidinone. The unique attribute of the quantum dots, possessing a multiple chromophoric band-gap structure, originates from the presence of g-C3N4, defect-related emissive traps, and grain boundaries. Thus, an appropriate excitation wavelength induces a conjugated pi electron system to fulfill the most probable absorption band, resulting in wavelength-dependent emissions including ultraviolet, visible and infrared light. The quantum yield of the NGQD and CNQD samples can reach as high as 68.1%. Accordingly, a light-emitting device using the combination of the NGQD and CNQD powder embedded polymeric film can emit white-like light with ultra-high power-conversion efficiency.
Discovery of two new magnesium-bearing species in IRC+10216: MgC3N and MgC4H
(2019-09-23)
Cernicharo, J.
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Cabezas, C.
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Pardo, J. R.
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Agundez, M.
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Bermudez, C.
We report on the detection of two series of harmonically related doublets in IRC +10216. From the observed frequencies, the rotational constant of the first series is B = 1380.888 MHz and that of the second series is B = 1381.512 MHz. The two series correspond to two species with a (2)Sigma electronic ground state. After considering all possible candidates, and based on quantum chemical calculations, the first series is assigned to MgC3N and the second to MgC4H. For the latter species, optical spectroscopy measurements support its identification. Unlike diatomic metal-containing molecules, the line profiles of the two new molecules indicate that they are formed in the outer layers of the envelope, as occurs for MgNC and other polyatomic metal-cyanides. We also confirm the detection of MgCCH that was previously reported from the observation of two doublets. The relative abundance of MgC3N with respect to MgNC is close to one while that of MgC4H relative to MgCCH is about ten. The synthesis of these magnesium cyanides and acetylides in IRC +10216 can be explained in terms of a two-step process initiated by the radiative association of Mg+ with large cyanopolyynes and polyynes followed by the dissociative recombination of the ionic complexes.
Incidence of retinal vein occlusion with longterm exposure to ambient air pollution
(2019-09-24)
Zhang, Han-Wei
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Lin, Chao-Wen
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Kok, Victor C.
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Tseng, Chun-Hung
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Lin, Yuan-Pei
This study aimed to investigate whether long-term exposure to airborne hydrocarbons, including volatile organic compounds, increases the risk of developing retinal vein occlusion (RVO) among the population of Taiwan. A retrospective cohort study involving 855,297 people was conducted. Cox proportional hazards regression analysis fitted the multiple pollutant models for two targeted pollutants, including total hydrocarbons (THC), nonmethane hydrocarbons (NMHC) were used, and the risk of RVO was estimated. The chi-squared test and one-way analysis of variance were used to test differences in demographics and comorbidity distribution among tertiles of the targeted pollutants. Before controlling for multiple pollutants, hazard ratios for the overall population were 19.88 (95% CI: 17.56-22.50) at 0.51-ppm increases in THC and 4.33 (95% CI: 3.97-4.73) at 0.27-ppm increases in NMHC. The highest adjusted hazard ratios for different multiple pollutant models of each targeted pollutant were statistically significant (all p values were.0.05) for all patients at 29.67 (95% CI: 25.57-34.42) for THC and 16.24 (95% CI: 14.14-18.65) for NMHC. Our findings suggest that long-term exposure to THC and NMHC contribute to RVO development.
Heteroepitaxy of Co-Based Heusler Compound/Muscovite for Flexible Spintronics
(2019-09-25)
Chen, Yi-Cheng
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Yen, Min
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Lai, Yu-Hong
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Markou, Anastasios
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Zhang, Liguo
Materials with high spin-polarization play an important role in the development of spintronics. Co-based Heusler compounds are a promising candidate for practical applications because of their high Curie temperature and tunable half-metallicity. However, it is a challenge to integrate Heusler compounds into thin film heterostructures because of the lack of control on crystallinity and chemical disorder, critical factors of novel behaviors. Here, muscovite is introduced as a growth substrate to fabricate epitaxial Co2MnGa films with mechanical flexibility. The feature of heteroepitaxy is evidenced by the results of X-ray diffraction and transmission electron microscopy. Moreover, high chemical ordering with superior properties is delivered according to the observation of large Hall conductivity (680 Omega(-1) cm(-1)) and highly saturated magnetic moment (similar to 3.93 mu(B)/f.u.), matching well with bulk crystals. Furthermore, the excellence of magnetic and electrical properties is retained under the various mechanical bending conditions. Such a result suggests that the development of Co2MnGa/muscovite heteroepitaxy provides not only a pathway to the thin film heterostructure based on high-quality Heusler compounds but also a new aspect of spintronic applications on flexible substrates.
The impact of heterogeneous anisotropy of porous media on density-driven convection
(2019-09-26)
Li, Qian
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Cai, Weihua
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Tang, Xiaojing
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Chen, Yicheng
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Li, Bingxi
Purpose The aim of this study is to numerically simulate the density-driven convection in heterogeneous porous media associated with anisotropic permeability field, which is important to the safe and stable long term CO2 storage in laminar saline aquifers. Design/methodology/approach The study uses compact finite difference and the pseudospectral method to solve Darcy's law. Findings The presence of heterogeneous anisotropy may result in non-monotonic trend of the breakthrough time and quantity of CO2 dissolved in the porous medium, which are important to the CO2 underground storage. Originality/value The manuscript numerically study the convective phenomena of mixture contained CO2 and brine. The phenomena are important to the process of CO2 enhanced oil recovery. Interesting qualitative patterns and quantitative trends are revealed in the manuscript.
陳世彬教授榮獲科技部「吳大猷先生紀念獎」
(國立陽明大學, 2019-09-30)
陽明電子報編輯小組
本校臨床醫學研究所陳世彬教授針對最嚴重也最危險的頭痛「RCVS」，以及造成全世界最多人失能的神經科疾病「偏頭痛」，深入進行病...
社團博覽會暨迎新晚會，熱烈歡迎新鮮人
(國立陽明大學, 2019-09-30)
董芷伶
;
陽明電子報編輯小組
一年一度的社團博覽會於9月4 日、5日兩天舉行，第一天共有41個社團攤位、3個校隊攤位參加，幾乎陽明所有社團全員出動！「社團博覽會」是由課外活動輔導組和學生會共同策劃，提供社團設攤招生、宣傳的活動。活動對象主要是新生，故以往都在新生入學指導的第二天舉辦。今（108）年由於新生入學日程改制，社團博覽會改於入學典禮前日（9/4）及當日（9/5）舉辦。
陽明成立「健康一體研究中心」，推動台灣防疫戰略
(國立陽明大學, 2019-09-30)
陽明電子報編輯小組
為協助台灣發展人類－動物－環境「健康一體」（One Health）防疫戰略，陽明率國內之先，9月24日成立「健康一體研究中心」，將與國...