Browsing by Issue Date, starting with "2019-11-04"

Now showing 1 - 20 of 6472

High on/off ratio black phosphorus based memristor with ultra-thin phosphorus oxide layer
(2019-11-04)
Wang, Yudan
;
Wu, Facai
;
Liu, Xingqiang
;
Lin, Jun
;
Chen, Jui-Yuan
The scaling down of switching media encounters high leakage current in the traditional oxide material based memristors, resulting in high power consumption of chips. Two-dimensional (2D) materials promise an ultimate device scaling down to atomic layer thickness. Herein, black phosphorus (BP) and its self-assembly phosphorous oxide (BP) memristors are constructed, which leverages the high on/off ratio operation of oxides and low leakage current of 2D materials with high performance. The memristors exhibit reproducible and reliable switching characteristics with the on/off ratio >10(7) and data retention >10(4) s. Depending on the high reproducibility, basic "AND" and "OR" gates have been constructed on flexible substrates. Moreover, on the basis of the symmetry and linearity of conductance in the devices, the neural network simulation for supervised learning presents an online learning accuracy of 91.4%. This work opens an avenue for future flexible electronics.
Ash2l interacts with Oct4-stemness circuitry to promote super-enhancer-driven pluripotency network
(2019-11-04)
Tsai, Ping-Hsing
;
Chien, Yueh
;
Wang, Mong-Lien
;
Hsu, Chih-Hung
;
Laurent, Benoit
Pluripotency and cell fates can be modulated through the regulation of super-enhancers; however, the underlying mechanisms are unclear. Here, we showed a novel mechanism in which Ash2l directly binds to super-enhancers of several stemness genes to regulate pluripotency and self-renewal in pluripotent stem cells. Ash2l recruits Oct4/Sox2/Nanog (OSN) to form Ash2l/OSN complex at the super-enhancers of Jarid2, Nanog, Sox2 and Oct4, and further drives enhancer activation, upregulation of stemness genes, and maintains the pluripotent circuitry. Ash2l knockdown abrogates the OSN recruitment to all super-enhancers and further hinders the enhancer activation. In addition, CRISPRi/dCas9-mediated blocking of Ash2l-binding motifs at these super-enhancers also prevents OSN recruitment and enhancer activation, validating that Ash2l directly binds to super-enhancers and initiates the pluripotency network. Transfection of Ash2l with W118A mutation to disrupt Ash2l-Oct4 interaction fails to rescue Ash2l-driven enhancer activation and pluripotent gene upregulation in Ash2l-depleted pluripotent stem cells. Together, our data demonstrated Ash2l formed an enhancer-bound Ash2l/OSN complex that can drive enhancer activation, govern pluripotency network and stemness circuitry.
The Development of Controllable Magnetic Driven Microphysiological System
(2019-11-07)
Yang, Jia-Wei
;
Chen, Yu-Wei
;
Ho, Pei-Yi
;
Jiang, Liane
;
Hsieh, Kuan Yu
Current research has enabled the use of microphysiological systems and creation of models for alveolar and pulmonary diseases. However, bottlenecks remain in terms of medium- and long-term regulation of cell cultures and their functions in microchannel systems, as well as in the enhancement of in vitro representation of alveolar models and reference values of the data. Currently used systems also require on-chip manufacturing of complex units, such as pumps, tubes, and other cumbersome structures for maintaining cells in culture. In addition, system simplification and minimization of all external and human factors major challenges facing the establishment of in vitro alveolar models. In this study, a magnetically driven dynamic alveolus cell-culture system has been developed to use controlled magnetic force to drive a magnetic film on the chip, thereby directing the fluid within it to produce a circulating flow. The system has been confirmed to be conducive with regard to facilitating uniform attachment of human alveolar epithelial cells and long-term culture. The cell structure has been recapitulated, and differentiation functions have been maintained. Subsequently, reactions between silica nanoparticles and human alveolar epithelial cells have been used to validate the effects and advantages of the proposed dynamic chip-based system compared to a static environment. The innovative concept of use of a magnetic drive has been successfully employed in this study to create a simple and controllable yet dynamic alveolus cell-culture system to realize its functions and advantages with regard to in vitro tissue construction.
Curved block copolymer nanodiscs: structure transformations in cylindrical nanopores using the nonsolvent-assisted template wetting method
(2019-11-07)
Lin, Yu-Liang
;
Cheng, Ming-Hsiang
;
Chang, Chun-Wei
;
Chu, Chien-Wei
;
Liu, Chih-Ting
In this work, we study the structure transformations of cylinder-forming polystyrene-block-polydimethylsiloxane (PS31k-b-PDMS14.5k) confined in cylindrical nanopores. PS-b-PDMS nanotubes, nanospheres, and curved nanodiscs are ingeniously prepared by a facile template wetting strategy using anodic aluminum oxide (AAO) templates. Quantitative analyses of the structure transformations from nanospheres to curved nanodiscs are also conducted, showing that the lengths of the curved nanodiscs can be controlled by adjusting the annealing temperature and time. Furthermore, the PDMS domains of the nanostructures can be selectively etched using HF solutions, generating porous PS nanostructures. This work not only offers versatile routes to prepare block copolymer nanostructures with controlled shapes but also provides a deeper understanding of the structure transformation of block copolymers in confined geometries.
Secondary ion mass spectrometry to verify the implantation of magnetic ions in nanodiamonds
(2019-11-07)
Lin, Bo-Rong
;
Wang, Chiung-Chi
;
Chen, Chien-Hsu
;
Kunuku, Srinivasu
;
Hsiao, Tung-Yuan
Ion implantation is used to create nanodiamonds (NDs) with embedded magnetic ions for use in a wide range of biological and medical applications; however, the effectiveness of this process depends heavily on separating magnetic NDs from nonmagnetic ones. In this study, we use secondary ion mass spectrometry to verify the implantation of magnetic ions in NDs and the success of separation. When applied to a series of NDs with embedded iron or manganese ions, the sorting tool used in this study proved highly effective in selecting magnetic NDs. Besides, multienergy ion implantation and precise thickness control of NDs coating on the silicon wafer were suggested to improve this technology. Published under license by AIP Publishing.
Alkoxy Chain Number Effect on Self-Assembly of a Trigonal Molecule at the Liquid/Solid Interface
(2019-11-07)
Tahara, Kazukuni
;
Nakayama, Ruri
;
Maeda, Matsuhiro
;
De Feyter, Steven
;
Tobe, Yoshito
We herein investigated the effect of the number of alkoxy chains on the two-dimensional self-assembly of a trigonal molecular building block. To this end, a dehydrobenzo[12]-annulene (DBA) derivative, DBA-OC14-OC1 having three tetradecyloxy chains and three methoxy groups in an alternating manner, was synthesized. Scanning tunneling microscopy (STM) observations at the 1,2,4-trichlorobenzene (TCB)/graphite interface revealed that DBA-OC14-OC1 forms three monolayer structures: porous honeycomb, parallelogram, and hexagonal A structures. At the 1-phenyloctane (PO)/graphite interface, DBA-OC14-OC1 also forms three structures: parallelogram, hexagonal B, and dense linear structures. In contrast to the previously reported DBA derivative DBA-OC14 having six tetradecyloxy chains, DBA-OC14-OC1 shows structural polymorphism with a variety of alkyl chain interaction modes. Because in the observed patterns DBA-OC14-OC1 adopts a low symmetric C-s or C-1 geometry, the variation of the interaction modes and the resulting network patterns likely originate from the conformational flexibility on surface of this DBA by decreasing the number of alkyl chains. Molecular mechanics simulations gave insight into the structural and energy aspects of this pattern formation. We also discussed the role of solvents, TCB and PO, on the polymorph formation.
Enhancing the Seebeck effect in Ge/Si through the combination of interfacial design features
(2019-11-08)
Nadtochiy, Andriy
;
Kuryliuk, Vasyl
;
Strelchuk, Viktor
;
Korotchenkov, Oleg
;
Li, Pei-Wen
Due to their inherent physical properties, thin-film Si/SiGe heterostructures have specific thermal management applications in advanced integrated circuits and this in turn is essential not only to prevent a high local temperature and overheat inside the circuit, but also generate electricity through the Seebeck effect. Here, we were able to enhance the Seebeck effect in the germanium composite quantum dots (CQDs) embedded in silicon by increasing the number of thin silicon layers inside the dot (multi-fold CQD material). The Seebeck effect in the CQD structures and multi-layer boron atomic layer-doped SiGe epitaxial films was studied experimentally at temperatures in the range from 50 to 300 K and detailed calculations for the Seebeck coefficient employing different scattering mechanisms were made. Our results show that the Seebeck coefficient is enhanced up to approximate to 40% in a 3-fold CQD material with respect to 2-fold Ge/Si CQDs. This enhancement was precisely modeled by taking into account the scattering of phonons by inner boundaries and the carrier filtering by the CQD inclusions. Our model is also able to reproduce the observed temperature dependence of the Seebeck coefficient in the B atomic layer-doped SiGe fairly well. We expect that the phonon scattering techniques developed here could significantly improve the thermoelectric performance of Ge/Si materials through further optimization of the layer stacks inside the quantum dot and of the dopant concentrations.
搖你千遍也不厭倦！別再喝含糖飲料了
(2019-11-10)
石恩亞
;
Department of Communication and Technology
;
傳播與科技學系
台灣人愛喝手搖杯，飲料店密集為全球之冠，國內外多項研究報告顯示，如果每日喝超過2杯含糖飲品者容易早逝，原因大多為心血管疾病、糖尿病、癌症，警告飲料不離手的人們「喝越多，死越快」。
Face ID是進步還是危機？
(2019-11-10)
陳婉宣
;
Department of Communication and Technology
;
傳播與科技學系
人臉辨識系統象徵著科技的進步，帶來了無限的可能性。但怎麼使用？用在哪裡？是否會造成不同的影響？本文討論人臉辨識系統的應用及威脅。
數位脫單路——交友軟體的安全性與法規爭議
(2019-11-10)
陳姝芸
;
Department of Communication and Technology
;
傳播與科技學系
使用交友軟體已成為現代人普遍交友管道之一，然而其造成的犯罪問題、消費者權益侵犯與目前尚未完備的相關法規，始終是社會上不容忽視的議題。
我們正在變成塑膠人？塑膠污染的反噬
(2019-11-10)
李芝謙
;
Department of Communication and Technology
;
傳播與科技學系
塑膠污染早已是舊聞，但你知道吃進塑膠的動物，不只有海鳥和海龜，人類也開始吃塑膠了嗎？研究發現，人們一年大約食入5萬個塑膠微粒，而這還只是冰山一角而已！
總編輯的話
(2019-11-10)
黃心姵
;
Department of Communication and Technology
;
傳播與科技學系
本期為喀報323期，共計8篇文章，包含三篇社會議題、四篇科技新知、一篇人物特寫。本篇頭題為王會瑄的〈網紅旋風席捲　吃什麼誰說了算？〉。本期文章多探討當科技日新月異，生活越便利的同時，隨之產生的社會問題。
網紅旋風席捲　吃什麼誰說了算？
(2019-11-10)
王會瑄
;
Department of Communication and Technology
;
傳播與科技學系
身處在這個高度依賴搜索引擎的消費時代，在口碑經濟的浪潮下，網紅如何影響我們的購物決策，又將帶領我們的飲食健康走向何方呢？
要讓台南家鄉味「鍋燒意麵」飄香國際－Waa Wei
(2019-11-10)
蕭蕙崎
;
Department of Communication and Technology
;
傳播與科技學系
鍋燒意麵是台灣獨一無二的麵食文化，Waa Wei透過一碗碗的鍋燒意麵，立足台灣、放眼世界。
當個夜貓子，對大腦有甚麼影響？
(2019-11-10)
李旻珊
;
Department of Communication and Technology
;
傳播與科技學系
只是晚睡而已，為甚麼補了眠還是那麼累？不只要睡得夠，更需要「睡對時間」。
心碎喝酒，越常喝越「心痛」！酒精是敵還是友？
(2019-11-10)
施詞萱
;
Department of Communication and Technology
;
傳播與科技學系
一天一小杯，看似無害又是許多人放鬆的方法。但是有研究指出，頻繁地喝酒相比久久一次喝到爛醉，更會影響健康問題！到底喝酒對於人體而言是敵？還是友呢？
Significant predictive factors of the severity and outcomes of the first attack of acute angioedema in children
(2019-11-11)
Syue, Yuan-Jhen
;
Li, Chao-Jui
;
Chen, Wen-Liang
;
Lee, Tsung-Han
;
Huang, Cheng-Chieh
Background The initial episode of angioedema in children can be potential life-threatening due to the lack of prompt identification and treatment. We aimed to analyze the factors predicting the severity and outcomes of the first attack of acute angioedema in children. Methods This was a retrospective study with 406 children (< 18 years) who presented in the emergency department (ED) with an initial episode of acute angioedema and who had subsequent follow-up visits in the out-patient department from January 2008 to December 2014. The severity of the acute angioedema was categorized as severe (requiring hospital admission), moderate (requiring a stay in the short-term pediatric observation unit [POU]), or mild (discharged directly from the ED). The associations among the disease severity, patient demographics and clinical presentation were analyzed. Result In total, 109 (26.8%) children had severe angioedema, and the majority of those children were male (65.1%). Most of the children were of preschool age (56.4%), and only 6.4% were adolescents. The co-occurrence of pyrexia or urticaria, etiologies of the angioedema related to medications or infections, the presence of respiratory symptoms, and a history of allergies (asthma, allergic rhinitis) were predictors of severe angioedema (all p < 0.05). Finally, the duration of angioedema was significantly shorter in children who had received short-term POU treatment (2.1 +/- 1.1 days) than in those who discharged from ED directly (2.3 +/- 1.4 days) and admitted to the hospital (3.5 +/- 2.0 days) (p < 0.001). Conclusion The co-occurrence of pyrexia or urticaria, etiologies related to medications or infections, the presence of respiratory symptoms, and a history of allergies were predictors of severe angioedema. More importantly, short-term POU observation and prompt treatment might be benefit for patients who did not require hospital admission.
Effects of TiO2 and SDC addition on the properties of YSZ electrolyte
(2019-11-12)
Shen, Chin-Tien
;
Lee, Kan-Rong
;
Hsieh, Yu-Pin
;
Lee, Sheng-Wei
;
Chang, Jeng-Kuei
In this study, we investigate the effects of adding titanium dioxide (TiO2) and samarium doped cerium oxide (SDC) on the properties of yttrium-stabilized zirconia (YSZ) electrolyte. The microstructure, mechanical, and electrochemical properties of the electrolyte are investigated. The performance in CO2 electrolysis is measured by supplying carbon dioxide to Ni-YSZ electrode and nitrogen to LSM electrode. Results show that TiO2 and SDC addition can reduce the sintering temperature and increase grain size. The ionic conductivity is 0.123 S cm(-1) at 1000 degrees C. In addition, the thermal expansion coefficient at 1000 degrees C is 8.25 x 10(-6)K(-1). The current density of the cell is 439 mA cm(-2) at 1.3 V and 1000 degrees C in solid oxide electrolysis cell. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Morphological and Molecular Defects in Human Three-Dimensional Retinal Organoid Model of X-Linked Juvenile Retinoschisis
(2019-11-12)
Huang, Kang-Chieh
;
Wang, Mong-Lien
;
Chen, Shih-Jen
;
Kuo, Jean-Cheng
;
Wang, Won-Jing
X-linked juvenile retinoschisis (XLRS), linked to mutations in the RS1 gene, is a degenerative retinopathy with a retinal splitting phenotype. We generated human induced pluripotent stem cells (hiPSCs) from patients to study XLRS in a 3D retinal organoid in vitro differentiation system. This model recapitulates key features of XLRS including retinal splitting, defective retinoschisin production, outer-segment defects, abnormal paxillin turnover, and impaired ER-Golgi transportation. RS1 mutation also affects the development of photoreceptor sensory cilia and results in altered expression of other retinopathy-associated genes. CRISPR/Cas9 correction of the disease-associated C625T mutation normalizes the splitting phenotype, outer-segment defects, paxillin dynamics, ciliary marker expression, and transcriptome profiles. Likewise, mutating RS1 in control hiPSCs produces the disease-associated phenotypes. Finally, we show that the C625T mutation can be repaired precisely and efficiently using a base-editing approach. Taken together, our data establish 3D organoids as a valid disease model.
Minimizing machine assignment costs over Delta-approximate solutions of the scheduling problem P parallel to C-max
(2019-11-12)
Kononov, A. V.
;
Kovalyov, M. Y.
;
Lin, B. M. T.
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Bi-criteria lexicographical minimization problems with the makespan as the primary objective and the total machine assignment costs as the secondary objective have been recently introduced to the scheduling research, and polynomial time (r + 1, 1)-approximation algorithms have been suggested for their solution, where 1 < r < 2 is the performance ratio of an approximation algorithm for P parallel to C-max. We improve these results by presenting a polynomial time (1.5r - 1, 1)-approximation algorithm for the additive cost type. Then, we introduce a problem of minimizing the total machine assignment cost over the Delta-approximate solutions of the makespan minimization problem. We prove that this new problem is strongly NP-hard and pseudo-polynomially non-approximable in general. A polynomial time approximation algorithm with a guaranteed approximation ratio is presented for the additive cost type and bounded ratio between the maximal and minimal machine costs. An O (mn(2k)) time dynamic programming algorithm is also presented, where k is the fixed number of distinct job processing times. (C) 2019 Elsevier B.V. All rights reserved.