Browsing by Issue Date, starting with "2017-01-25"

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Diversity and enterotype in gut bacterial community of adults in Taiwan
(2017-01-25)
Liang, Chao
;
Tseng, Han-Chi
;
Chen, Hui-Mei
;
Wang, Wei-Chi
;
Chiu, Chih-Min
Background: Gastrointestinal microbiota, particularly gut microbiota, is associated with human health. The biodiversity of gut microbiota is affected by ethnicities and environmental factors such as dietary habits or medicine intake, and three enterotypes of the human gut microbiome were announced in 2011. These enterotypes are not significantly correlated with gender, age, or body weight but are influenced by long-term dietary habits. However, to date, only two enterotypes (predominantly consisting of Bacteroides and Prevotella) have shown these characteristics in previous research; the third enterotype remains ambiguous. Understanding the enterotypes can improve the knowledge of the relationship between microbiota and human health. Results: We obtained 181 human fecal samples from adults in Taiwan. Microbiota compositions were analyzed using next-generation sequencing (NGS) technology, which is a culture-independent method of constructing microbial community profiles by sequencing 16S ribosomal DNA (rDNA). In these samples, 17,675,898 sequencing reads were sequenced, and on average, 215 operational taxonomic units (OTUs) were identified for each sample. In this study, the major bacteria in the enterotypes identified from the fecal samples were Bacteroides, Prevotella, and Enterobacteriaceae, and their correlation with dietary habits was confirmed. A microbial interaction network in the gut was observed on the basis of the amount of short-chain fatty acids, pH value of the intestine, and composition of the bacterial community (enterotypes). Finally, a decision tree was derived to provide a predictive model for the three enterotypes. The accuracies of this model in training and independent testing sets were 97.2 and 84.0%, respectively. Conclusions: We used NGS technology to characterize the microbiota and constructed a predictive model. The most significant finding was that Enterobacteriaceae, the predominant subtype, could be a new subtype of enterotypes in the Asian population.
Resistance Switching Characteristics Induced by O-2 Plasma Treatment of an Indium Tin Oxide Film for Use as an Insulator in Resistive Random Access Memory
(2017-01-25)
Chen, Po-Hsun
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Chang, Ting-Chang
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Chang, Kuan-Chang
;
Tsai, Tsung-Ming
;
Pan, Chih-Hung
In this study, an O-2 inductively coupled plasma (ICP) treatment was developed in order to modify the characteristics of indium tin oxide (ITO) film for use as an insulator in resistive random access memory (RRAM). After the O-2 plasma treatment, the previously conductive ITO film is oxidized and becomes less conductive. In addition, after capping the same ITO material for use as a top electrode, we found that the ITO/ITO (O-2 plasma)/TiN device exhibits very stable and robust resistive switching characteristics. On the contrary, the nontreated ITO film for use as an insulator in the ITO/ ITO/TiN device cannot perform resistance switching behaviors. The material analysis initially investigated the ITO film characteristics with and without O-2 plasma treatment. The surface was less rough after O-2 plasma treatment. However, the molar concentration of each element and measured sheet resistance results for the O-2-plasma-treated ITO film were dramatically modified. Next, electrical measurements were carried out to examine the resistance switching stability under continuous DC and AC operation in this ITO/ITO(O-2 plasma)/TiN device. Reliability tests, including endurance and retention, also proved its capability for use in data storage applications. In addition to these electrical measurements, current fitting method experiments at different temperatures were performed to examine and confirm the resistance switching mechanisms. This easily fabricated device, using a simple material combination, achieves excellent performance by using ITO with an O-2 plasma treatment and can further the abilities of RRAM for use in remarkable potential applications.
A cost-effective fabrication of iridium oxide films as biocompatible electrostimulation electrodes for neural interface applications
(2017-01-25)
Chen, Yong-Min
;
Chung, Tsai-Wei
;
Wu, Pu-Wei
;
Chen, Po-Chun
;
材料科學與工程學系
Electrostimulation medical devices for neural diseases require electroactive and biocompatible interface materials to transmit signals from electrodes to targeting tissues. Iridium oxide is an attractive ceramic material for neurostimulation electrodes due to its desirable stability and biocompatibility. In this study, we developed a cost effective and thickness controllable process to fabricate iridium oxide film by chemical bath deposition (CIROF). Surface morphology, crystallinity, roughness, hydrophilicity, and charge storage capacity as well as biocompatibility of the CIROFs with different thicknesses were analyzed. Accordingly, the CIROFs present rough and hydrophilic surfaces for cell attachment and good biocompatibility for cell viability. In addition, the charge storage capacity (CSC) of the as-deposited and the annealed CIROFs were 78.29 mC/cm(2) and 71.76 mC/cm(2), respectively. Consequently, these results show advantages that make the CIROF a promising neurostimulation electrode material for implantable medical devices in neural systems. (C) 2016 Elsevier B.V. All rights reserved.
Thickness-dependent magnetotransport properties and terahertz response of topological insulator Bi2Te3 thin films
(2017-01-25)
Phuoc Huu Le
;
Liu, Po-Tsun
;
Luo, Chih Wei
;
Lin, Jiunn-Yuan
;
Wu, Kaung Hsiung
We report the thickness (d) dependence of structural, morphological, magneto-transport properties as well as terahertz (THz) response in the 0.25-2.25 THz range of topological insulator Bi2Te3 thin films grown by pulsed laser deposition (PLD). The Bi2Te3 films exhibit a highly c-axis orientation (textured films) and two Raman-active modes of E-g(2) at 102.5 cm(-1) and A(1g)(2) at 134.8 cm(-1). The films obtain relatively low carrier concentration between 2.0 x 10(19) and 4.4 x 10(19) cm(-3). The films present two-dimensional weak (2D WAL) antilocalization magnetoresistance in a low magnetic field (B) and the 2D WAL shows thickness dependence, suggesting the presence of topological surface states (TSS). The THz transmittance increases owing to increased resistivity (associated with a decreased carrier concentration) when film thickness decreases from 152 to 16 QL. The complex conductance is well described by the Drude-Lorentz model with three components of the Drude surface, Drude bulk, and phonon. The Drude spectral weight (SW) of the surface is dominant and independent of the thickness. Besides, the Drude SW of the bulk and phonon SW linearly increase with increasing thickness. (C) 2016 Elsevier B.V. All rights reserved.
Fluorene Conjugated Polymer/Nickel Oxide Nanocomposite Hole Transport Layer Enhances the Efficiency of Organic Photovoltaic Devices
(2017-01-25)
Chiou, Guan-Chiun
;
Lin, Ming-Wei
;
Lai, Yu-Ling
;
Chang, Chiao-Kai
;
Jiang, Jian-Ming
A nanocomposite layer comprising the conjugated polymer poly[(9,9-bis(3\'(N,N-dimethylamino)propy1)-2,7-fluorene)-alt-2,7-(9,9-dioctyl)fluorene] (PFN) and nickel oxide (NiOx) has been employed as the hole transport layer (HTL) in organic photovoltaics (OPVs) featuring PBDTTBO-C-8 and [6,6] -phenyl -C-71-butyric acid methyl ester (PC71BM) as the active layer. The optimal device incorporating the PFN:NiOx nanocomposite as the HTLs displayed a power conversion efficiency (PCE) to 6.2%, up from 4.5% for the corresponding device incorporating pristine NiOx as the HTL layer: a nearly 40% improvement in PCE. X-ray photoelectron spectroscopy (XPS) was used to determine the types of chemical bonding, ultraviolet photoelectron spectroscopy (UPS) to measure the change in work function, and atomic force microscopy (AFM) to examine the morphology of the composite layers. The growth of nickel trioxide, Ni2O3, in the PFN:NiOx layer played a key role in producing the p-doping effect and in tuning the work function, thereby improving the overall device performance.
SYSTEM AND METHOD FOR MEASURING MICROFLUCTUATION OF ACCOMMODATION
(2017-01-26)
Mang Ou-Yang
;
Jin-Chern Chiou
;
Ting-Wei Huang
;
Yi-Chun Tsai
A system for measuring microfluctuation of accommodation comprises a measuring module and a processing module. The measuring module includes at least one first sensing element attached to the area around an eye of a testee for measuring an EMG signal. The processing module is coupled with the measuring module for picking up a specific frequency range of the EMG signal as a measurement index of microfluctuation of accommodation, wherein the specific frequency range is between 0.1 Hz and 100 Hz. The system allows the testee to be tested in an open field of view and exempts the testee from experiencing fatigue in the muscle around the eyes. The system is compact and convenient to carry. A method for measuring microfluctuation of accommodation is also disclosed.
Directly Probing Intermolecular Structural Change of a Core Fragment of beta(2)-Microglobulin Amyloid Fibrils with Low-Frequency Raman Spectroscopy
(2017-01-26)
Shigeto, Shinsuke
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Chang, Chun-Fu
;
Hiramatsu, Hirotsugu
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應用化學系
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Department of Applied Chemistry
Amyloid fibrils, which are ordered aggregates of proteins or peptides, have attracted keen interest because their deposition causes serious human diseases. Despite many studies utilizing X-ray crystallography, solid-state NMR, and other methods, intermolecular interactions governing the fibril formation remain largely unclear. Here, we used low-frequency Raman (LFR) spectroscopy to investigate the intermolecular beta-sheet structure of a core fragment of beta(2)-microglobulin amyloid fibrils, beta(2)m(21-29), in aqueous buffer solutions. The LFR spectra (approximately 10-200 cm(-1)) of beta(2)m(21-29) amyloid fibrils measured at different pH values (ranging from 6.8 to 8.0) revealed a broad-spectral pattern with a maximum at similar to 80 cm(-1) below pH 7.2 and at similar to 110 cm(-1) above pH 7.4. This observation is attributed to a pH-dependent structural change from an antiparallel to a parallel intermolecular beta-sheet structure. Multivariate curve resolution-alternating least-squares (MCR-ALS) analysis enabled us to decompose the apparently monotonous LFR spectra into three distinctly different contributions: intermolecular vibrations of the parallel and antiparallel beta-sheets and intramolecular vibrations of the peptide backbone. Peak positions of the obtained LFR bands not only exhibit a much more pronounced difference between the two beta-sheets than the conventional amide I band, but they also suggest stronger intermolecular interaction, due presumably to the hydrophobic effect, in the parallel beta-sheet than in the antiparallel beta-sheet. The present results show that LFR spectroscopy in combination with the MCR-ALS analysis holds promise for real-time tracking of the intermolecular dynamics of amyloid fibril formation under physiological conditions.
RNA helicase DDX3 maintains lipid homeostasis through upregulation of the microsomal triglyceride transfer protein by interacting with HNF4 and SHP
(2017-01-27)
Tsai, Tsung-Yuan
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Wang, Wei-Ting
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Li, Hao-Kang
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Chen, Wei-Ju
;
Tsai, Yu-Hong
Multifunctional RNA helicase DDX3 participates in HCV infection, one of the major causes of hepatic steatosis. Here, we investigated the role of DDX3 in hepatic lipid metabolism. We found that HCV infection severely reduced DDX3 expression. Analysis of intracellular triglyceride and secreted ApoB indicated that lipid accumulations were increased while ApoB secretion were decreased in DDX3 knockdown HuH7 and HepG2 cell lines. Down-regulation of DDX3 significantly decreased protein and transcript expression of microsomal triglyceride transfer protein (MTP), a key regulator of liver lipid homeostasis. Moreover, DDX3 interacted with hepatocyte nuclear factor 4 (HNF4) and small heterodimer partner (SHP), and synergistically up-regulated HNF4-mediated transactivation of MTP promoter via its ATPase activity. Further investigation revealed that DDX3 interacted with CBP/p300 and increased the promoter binding affinity of HNF4 by enhancing HNF4 acetylation. Additionally, DDX3 partially relieved the SHP-mediated suppression on MTP promoter by competing with SHP for HNF4 binding which disrupted the inactive HNF4/SHP heterodimer while promoted the formation of the active HNF4 homodimer. Collectively, these results imply that DDX3 regulates MTP gene expression and lipid homeostasis through interplay with HNF4 and SHP, which may also reveal a novel mechanism of HCV-induced steatosis.
Characterizing classical periodic orbits from quantum Green's functions in two-dimensional integrable systems: Harmonic oscillators and quantum billiards
(2017-01-30)
Chen, Y. F.
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Tung, J. C.
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Tuan, P. H.
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Yu, Y. T.
;
Liang, H. C.
A general method is developed to characterize the family of classical periodic orbits from the quantum Green's function for the two-dimensional (2D) integrable systems. A decomposing formula related to the beta function is derived to link the quantum Green's function with the individual classical periodic orbits. The practicality of the developed formula is demonstrated by numerically analyzing the 2D commensurate harmonic oscillators and integrable quantum billiards. Numerical analyses reveal that the emergence of the classical features in quantum Green's functions principally comes from the superposition of the degenerate states for 2D harmonic oscillators. On the other hand, the damping factor in quantum Green's functions plays a critical role to display the classical features in mesoscopic regime for integrable quantum billiards, where the physical function of the damping factor is to lead to the coherent superposition of the nearly degenerate eigenstates.
Evidence of preserved collagen in an Early Jurassic sauropodomorph dinosaur revealed by synchrotron FTIR microspectroscopy
(2017-01-31)
Lee, Yao-Chang
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Chiang, Cheng-Cheng
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Huang, Pei-Yu
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Chung, Chao-Yu
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Huang, Timothy D.
Fossilized organic remains are important sources of information because they provide a unique form of biological and evolutionary information, and have the long-term potential for genomic explorations. Here we report evidence of protein preservation in a terrestrial vertebrate found inside the vascular canals of a rib of a 195-million-year-old sauropodomorph dinosaur, where blood vessels and nerves would normally have been present in the living organism. The in situ synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectra exhibit the characteristic infrared absorption bands for amide A and B, amide I, II and III of collagen. Aggregated haematite particles (alpha-Fe2O3) about 6 similar to 8 mu m in diameter are also identified inside the vascular canals using confocal Raman microscopy, where the organic remains were preserved. We propose that these particles likely had a crucial role in the preservation of the proteins, and may be remnants partially contributed from haemoglobin and other iron-rich proteins from the original blood.
A Miniature Magnetic-Force-Based Three-Axis AC Magnetic Sensor with Piezoelectric/Vibrational Energy-Harvesting Functions
(2017-02-01)
Hung, Chiao-Fang
;
Yeh, Po-Chen
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Chung, Tien-Kan
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機械工程學系
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國際半導體學院
In this paper, we demonstrate a miniature magnetic-force-based, three-axis, AC magnetic sensor with piezoelectric/vibrational energy-harvesting functions. For magnetic sensing, the sensor employs a magnetic-mechanical-piezoelectric configuration (which uses magnetic force and torque, a compact, single, mechanical mechanism, and the piezoelectric effect) to convert x-axis and y-axis in-plane and z-axis magnetic fields into piezoelectric voltage outputs. Under the x-axis magnetic field (sine-wave, 100 Hz, 0.2-3.2 gauss) and the z-axis magnetic field (sine-wave, 142 Hz, 0.2-3.2 gauss), the voltage output with the sensitivity of the sensor are 1.13-26.15 mV with 8.79 mV/gauss and 1.31-8.92 mV with 2.63 mV/gauss, respectively. In addition, through this configuration, the sensor can harness ambient vibrational energy, i.e., possessing piezoelectric/vibrational energy-harvesting functions. Under x-axis vibration (sine-wave, 100 Hz, 3.5 g) and z-axis vibration (sine-wave, 142 Hz, 3.8 g), the root-mean-square voltage output with power output of the sensor is 439 mV with 0.333 mu W and 138 mV with 0.051 mu W, respectively. These results show that the sensor, using this configuration, successfully achieves three-axis magnetic field sensing and three-axis vibration energy-harvesting. Due to these features, the three-axis AC magnetic sensor could be an important design reference in order to develop future three-axis AC magnetic sensors, which possess energy-harvesting functions, for practical industrial applications, such as intelligent vehicle/traffic monitoring, processes monitoring, security systems, and so on.
視調節微波動之量測系統及方法
(2017-02-01)
歐陽盟
;
邱俊誠
;
黃庭緯
;
蔡宜君
一種視調節微波動之量測系統包含一量測模組以及一處理模組。量測模組包含至少一第一感測元件，其用以貼附於一受測者之眼睛周圍，以量測一肌電圖訊號。處理模組與量測模組耦合。處理模組用以擷取一特定頻率範圍之肌電圖訊號作為視調節微波動之一量測指標，其中特定頻率範圍為0.1 Hz至100 Hz。上述量測系統可讓受測者在開放視野下進行量測，以避免受測者眼睛周圍之肌肉產生疲勞，且體積相對較小而有利於攜帶。同時亦揭示一種視調節微波動之量測方法。
太空漂流指南－ 2017 交大建築展
(2017-02)
交通大學藝文中心
;
交大建築研究所
;
National Chiao Tung University Arts Center
;
Institute of Architecture NCTU
自有歷史以來，人類對於「太空」（space）的好奇和想像從未停歇，各個時代都不斷發展新的科技器物或理解觀點來詮釋太空的奧秘，一旦新的假說出現，又不斷被新的理論和發現所挑戰，將人類的所知極限推向一個更為神秘的邊疆。文明的演進讓人類直擊各種超乎預期的天文現象，積累了對於各樣星系與星球的微渺認知，但所有未知星球間的物理距離和人類心理的想像距離是一樣的廣大，這一切既來自於外在，也發生於自身，所有理性且好奇的探索皆一再追問人類的內心並喚起自省。交大建築所這次將建築創作比擬在開放宇宙中的移動，「太空漂流指南」網羅建築所全所設計課的作品，每門 Studio 都是一顆顆獨立星球，此時此刻的建築創作不標榜無懼的英雄冒險，而是專注地看待面對外在條件衝突下，創作者本身的自我掙扎和價值判斷。每件作品都是創作者與未知想像和目標物的來回映射，創作者的意念迥然多樣，相較以往直接的作品呈現，本次展覽企圖以太空敘事使觀者能更了解題目意義和作品背後的價值、創作方法和想像。
Carbodicarbenes or Bent Allenes
(2017-02-01)
Wang, Ting-Hsuan
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Chen, Wen-Ching
;
Ong, Tiow-Gan
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應用化學系
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Department of Applied Chemistry
The pursuit of unusual bonding environments of carbon species with non-octet electronic configurations has been quite active in fundamental organic and theoretical chemistry for many decades. In this respect, a distinct carbone species has been successfully isolated recently and defined as "carbodicarbene" or "bent allene." This neutral two-coordinated central carbon atom possesses two electron lone pairs, while its octet deficiency is overcome by sigma donation of N-heterocyclic carbenes (NHCs) bound to the central carbon. The present review is focused on the rich chemistry of carbodicarbenes in the aspects of synthesis, characterization, and ligand science of metal complex as well as their intrinsic reactivities.
Evaluation and Reliability Assessment of GaN-on-Si MIS-HEMT for Power Switching Applications
(2017-02-01)
Chou, Po-Chien
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Chen, Szu-Hao
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Hsieh, Ting-En
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Cheng, Stone
;
del Alamo, Jesus A.
This paper reports an extensive analysis of the physical mechanisms responsible for the failure of GaN-based metal-insulator-semiconductor (MIS) high electron mobility transistors (HEMTs). When stressed under high applied electric fields, the traps at the dielectric/III-N barrier interface and inside the III-N barrier cause an increase in dynamic on-resistance and a shift of threshold voltage, which might affect the long term stability of these devices. More detailed investigations are needed to identify epitaxy- or process-related degradation mechanisms and to understand their impact on electrical properties. The present paper proposes a suitable methodology to characterize the degradation and failure mechanisms of GaN MIS-HEMTs subjected to stress under various off-state conditions. There are three major stress conditions that include: V-DS = 0 V, off, and off (cascode-connection) states. Changes of direct current (DC) figures of merit in voltage step-stress experiments are measured, statistics are studied, and correlations are investigated. Hot electron stress produces permanent change which can be attributed to charge trapping phenomena and the generation of deep levels or interface states. The simultaneous generation of interface (and/or bulk) and buffer traps can account for the observed degradation modes and mechanisms. These findings provide several critical characteristics to evaluate the electrical reliability of GaN MIS-HEMTs which are borne out by step-stress experiments.
族譜
(國立陽明大學牙醫校友會, 2017-02)
陽明大學牙醫系系學會
[院系消息]
(國立交通大學資訊學院, 2017-02)
林珮雯
本刊每學期發刊一期，做為本院師生與系友、家長的溝通橋樑。每期報導本院近期研究現況，內容包括人事動態、學人來訪以及國際交流等。期能經由本刊使讀者掌握資訊學院最新動態，促進彼此互動。
Supramolecular control over the morphology of bio-inspired poly(3-hexylthiophene) for organic thin film transistors
(2017-02)
Lin, Yen-Ting
;
Singh, Ranjodh
;
Kuo, Shiao-Wei
;
Ko, Fu-Hsiang
;
材料科學與工程學系
We have developed a strategy for modifying the channel layer of organic thin film transistors (OTFTs) through side-chain induced self-organization into a well-ordered film. To obtain selectively self-patterned layers, we treated an adenine-functionalized poly(3-hexylthiophene) (PAT) with adenosine triphosphate (ATP). Using this strategy, interchain charge transport resulting from pi-conjugation was selected to control the polymer morphology, without the need of additional chemical synthetic processing. The side chain-induced self-organization can be understood in terms of supramolecular interactions. The pi-electrons were delocalized among the thiophene rings, thereby improving the interchain charge transport ability; the resulting planar pi-electron system in PAT: ATP resulted in closer intermolecular pep distances, facilitating enhanced charge carrier mobility within a fibrillar structure. The PAT: ATP-based OTFT device exhibited moderate to improved electronic characteristics, with an average field mobility of 3.2 x 10(-4) cm(2) V-1 s(-1) at -30 V and a threshold voltage (V-th) of 5 V, and an on/off current ratio of 10(6). This method has great potential for inducing selective intermolecular interactions in fully solution processed electronic devices. (C) 2016 Elsevier B.V. All rights reserved.
Multimodal Video-to-Near-Scene Annotation
(2017-02)
Chou, Chien-Li
;
Chen, Hua-Tsung
;
Lee, Suh-Yin
;
交大名義發表
;
資訊工程學系
Traditional video annotation approaches focus on annotating keyframes/shots or whole videos with semantic keywords. However, the extraction processes of keyframes/shots might lack semantic meanings, and it is hard to use a few keywords to describe the content of a long video with multiple topics. In this work, near- scenes, which contain similar concepts, topics, or semantic meanings, are designed for better video content understanding and annotation. We propose a novel framework of hierarchical video-to-near-scene annotation not only to preserve but also to purify the semantic meanings of near- scenes. To detect near-scenes, a pattern- based prefix tree is first constructed to fast retrieve near- duplicate videos. Then, the videos containing similar near- duplicate segments and similar keywords are clustered with consideration of multimodal features including visual and textual features. To enhance the precision of near-scene detection, a pattern-to-intensity- mark (PIM) method is proposed to perform precise frame- level near- duplicate segment alignment. For each near- scene, a video-to-concept distribution model is designed to analyze the representativeness of keywords and discriminations of clusters by the proposed potential term frequency and inverse document frequency and entropy. Tags are ranked according to video-to-concept distribution scores, and the tags with the highest scores are propagated to near-scenes detected. Extensive experiments demonstrate that the proposed PIM outperforms state-of-the-art approaches compared in terms of quality segments and quality frames for near-scene detection. Furthermore, the proposed framework of hierarchical video- to-near- scene annotation can achieve high quality of near-scene annotation in terms of mean average precision.
Gd2O3:RE3+ and GdAIO(3):RE3+ (RE = Eu, Dy) Phosphor: Synthesis, Characterization and Bioimaging Application
(2017-02-01)
Selvalakshmi, Thangaraj
;
Venkatesan, Parthiban
;
Wu, Shu-Pao
;
Velmathi, S.
;
Bose, A. Chandra
Citrate based sol-gel method is used to synthesize Gd2O3:RE3+ and GdAlO3: RE3+ (RE = Eu, Dy) phosphors. In the present work, the phosphors are characterized using the techniques like X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS) and photoluminescence spectroscopy (PL). Fluorescence confocal microscopy reveals the potential usage of phosphors in biological medium for biolabeling application. XRD patterns confirm the phase purity of Gd2O3 and GdAlO3. The crystallite size and lattice parameters are estimated from XRD result. FTIR spectra are used to investigate the functional group present in the phosphor. The optical emission properties imply that the emission peak positions on Eu3+ or Dy3+ ion are size and host independent. Finally, RAW 264.7 macrophages cell line is used to test the bioimaging performance of the phosphors.