Browsing by Issue Date, starting with "2019-01-30"

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Infections Caused by Carbapenem-Resistant Enterobacteriaceae: An Update on Therapeutic Options
(2019-01-30)
Sheu, Chau-Chyun
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Chang, Ya-Ting
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Lin, Shang-Yi
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Chen, Yen-Hsu
;
Hsueh, Po-Ren
Carbapenems are considered as last-resort antibiotics for the treatment of infections caused by multidrug-resistant Gram-negative bacteria. With the increasing use of carbapenems in clinical practice, the emergence of carbapenem-resistant pathogens now poses a great threat to human health. Currently, antibiotic options for the treatment of carbapenem-resistant Enterobacteriaceae (CRE) are very limited, with polymyxins, tigecycline, fosfomycin, and aminoglycosides as the mainstays of therapy. The need for new and effective anti-CRE therapies is urgent. Here, we describe the current understanding of issues related to CRE and review combination therapeutic strategies for CRE infections, including high-dose tigecycline, high-dose prolonged-infusion of carbapenem, and double carbapenem therapy. We also review the newly available antibiotics which have potential in the future treatment of CRE infections: ceftazidime/avibactam, which is active against KPC and OXA-48 producers; meropenem/vaborbactam, which is active against KPC producers; plazomicin, which is a next-generation aminoglycoside with in vitro activity against CRE; and eravacycline, which is a tetracycline class antibacterial with in vitro activity against CRE. Although direct evidence for CRE treatment is still lacking and the development of resistance is a concern, these new antibiotics provide additional therapeutic options for CRE infections. Finally, we review other potential anti-CRE antibiotics in development: imipenem/relebactam and cefiderocol. Currently, high-dose and combination strategies that may include the new beta-lactam/beta-lactamase inhibitors should be considered in severe CRE infections to maximize treatment success. In the future, when more treatment options are available, therapy for CRE infections should be individualized and based on molecular phenotypes of resistance, susceptibility profiles, disease severity, and patient characteristics. More high-quality studies are needed to guide effective treatment for infections caused by CRE.
Switching Behavior and Forward Bias Degradation of 700V, 0.2A, beta-Ga2O3 Vertical Geometry Rectifiers
(2019-01-30)
Yang, Jiancheng
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Fares, Chaker
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Ren, Fan
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Chen, Yen-Ting
;
Liao, Yu-Te
We report the switching recovery characteristics of large area (contact dimension 0.04 x 0.04 cm(2)) vertical geometry beta-Ga2O3 Schottky rectifiers, consisting of Si-doped epitaxial layers on conducting bulk substrates. Devices that were switched from forward current of 0.225 A to reverse off-state voltage of -700 V in an inductive load test circuit showed a recovery time (t(rr)) of 82 ns, with a reverse recovery current (I-rr) of 38 mA and dI/dt of -2.28 A. mu sec(-1). This shows the potential of Ga2O3 rectifiers for power switching applications, provided effective thermal management schemes can be implemented. Devices deliberately tested to failure under forward bias conditions exhibit delamination and cracking of the Ni/Au contact and underlying epitaxial Ga2O3 due to the low thermal conductivity of the Ga2O3. This failure mode is different to that under high reverse breakdown conditions, where pits formed by material failure under the high field generated at the edge of the rectifying contact occurs. (C) The Author(s) 2019. Published by ECS.
Microgroove Structure For Controlling Frost Nucleation and Manufacturing Method Thereof
(2019-01-31)
Ming-Chang Lu
;
Ching-Wen Lo
The present disclosure illustrates a microgroove structure for controlling frost nucleation, and the microgroove structure has a substrate which has a non-rough surface. The non-rough surface has one or more microgrooves extending along a first direction. The microgroove structure for controlling frost nucleation has nice anti-icing and deicing performances.
An electronic silicon-based memristor with a high switching uniformity
(2019-02-01)
Lu, Yang
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Alvarez, Ana
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Kao, Chung-Ho
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Bow, Jong-Shing
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Chen, San-Yuan
Metal-insulator-metal devices known as memristors offer voltage-regulated nanoscale conductivity and are of interest in the development of non-volatile random access memory. Typically, however, their tunable conductivity is the result of migrating ions within a stochastically formed filament, and as such their combined resistor-memory performance suffers. Here we show that amorphous silicon compositions, which are doped with oxygen or nitrogen and sandwiched between metal electrodes, can be used to create purely electronic memristors. The devices have coherent electron wave functions that extend to the full device thickness (more than 15 nm) and, despite the thinness and very high aspect ratio of the devices, electrons still follow an isotropic, three-dimensional pathway, thus providing uniform conductivity at the nanoscale. Such pathways in amorphous insulators are derived from overlapping gap states and regulated by trapped charge, which is stabilized by electron-lattice interaction. As a result, the nanometallic memristors also exhibit pressure-triggered insulator-to-metal transitions. Our silicon-based memristors, which could be readily integrated into silicon technology, are purely electronic and offer switching capabilities that are fast, uniform, durable, multi-state and low power.
Effects of Negative Electrodes Coated by ZnO with Different Morphologies on Electrochemical Performances and Safety of Lithium Ion Batteries
(2019-02-01)
Chang, Chia-Ming
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Lin, Hsiu-Fen
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Liao, Shih-Chieh
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Chiu, Hsin-Tien
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Liu, Chia-Erh
To improve the safety of lithium-ion batteries, this study applied topographically different ZnO to the surface of negative graphite electrodes to serve as heat-resistant layers and explored the effects of these layers on a battery's electrochemical and safety features. The results indicate that when using a tetrapod ZnO (T-ZnO) particle coating as a heat-resistant layer on a negative graphite electrode, ion diffusion is improved because T-ZnO has a three-dimensional network structure and forms highly porous layers. This causes batteries to retain excellent electrochemical characteristics even if they contain inactive substances. Moreover, the results of overcharge and penetration tests were satisfactory, suggesting that the batteries are highly safe.
An Offset Readout Current Sensing Scheme for One-Resistor RRAM-Based Cross-Point Array
(2019-02-01)
Chen, You-Da
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Chin, Albert
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
The uneven sneak-path currents in resistive random access memory (RRAM) severely constrain the array size. To overcome this issue, we propose an innovative readout scheme that can fully offset the sneak-path currents in one-resistor (1R) RRAM array. Furthermore, the bit cell resistance (R-cell) in an RRAM array can be simply evaluated as the ratio of read voltage (V-read) to the sensed offset current (I-offset). Even under extreme device distribution, a 512x512 array size is still obtained. This is the largest array among simple 1R RRAM, without using a selector device or extra transistor.
Introduction to the special issue on Tibet: Contemporary geodetic-geophysical observations and interpretations
(2019-02-01)
Hwang, Cheinway
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Shen, Wen-Bin
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Shum, C. K.
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Song, Xiaodong
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土木工程學系
Novel Reconfigurable Single-to-Balanced, Power-Dividing, and Single-Ended Filter With Frequency and Bandwidth Control
(2019-02-01)
Zhu, Xu
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Yang, Tao
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Chi, Pei-Ling
;
Xu, Ruimin
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電機工程學系
In this paper, a novel tunable filter with reconfigurable single-to-balanced (SE-BAL), power dividing (PD), and single-to-single-ended (SE) filtering functionalities is proposed, for the first time, without any additional switching circuit. The proposed filter only consists of three stepped-impedance resonators, which are loaded and connected by varactors in between. With a very simple and compact configuration, the proposed filter achieves multiple reconfigurable functionalities between SE-BAL filtering, PD filtering, and conventional SE bandpass filtering. Moreover, the reconfigurable SE-BAL, PD, and SE bandpass filter can not only offer continuously frequency tuning over a wide tuning range but also have independent bandwidth tuning and maintain good phase/amplitude balance in each tuning state. The proposed filter is designed and fabricated with the microstrip line technology; the measured results show that the SE-BAL, PD, and SE filtering functions can be continuously tuned from 1.02 to 1.32, 0.96 to 1.27, and 1 to 1.28 GHz, with 1-dB bandwidth tuning from 30 to 60, 30 to 110, and 70 to 130 MHz, respectively. The amplitude and phase imbalances of the SE-BAL and PD bandpass filter are less than 0.4 dB, 1.3 degrees and 0.5 dB, 1.5 degrees, respectively, in the passband of each tuning state. Good agreement was obtained between simulated and measured results.
Improved Negative-Capacitance Switch of Ferroelectric Field Effect Transistor Using Defect Passivation Engineering
(2019-02-01)
Cheng, Chun-Hu
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Fan, Chia-Chi
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Hsu, Hsiao-Hsuan
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Wang, Shih-An
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Chang, Chun-Yen
A ferroelectric negative-capacitance (NC) transistor using aluminum-doped hafnium oxide (HfAlOx) with fluorine passivation is successfully demonstrated. The fluorine-passivated device shows a nearly hysteresis-free forward/reverse swing of sub-30 mV dec(-1) for symmetric switch, a wide sub-60 mV (dec center dot swing)(-1) range over 4 decades of drain current, an ultralow off-leakage current of 4 fA mu m(-1), and a high on/off current ratio of >10(8). The fluorine defect passivation (FP) reduces oxygen vacancies of ferroelectric HfAlOx to mitigate interface depolarization field and thereby reinforce surface potential amplification effect during NC operation.
生物感測元件及其製造方法以及生物分子檢測方法
(2019-02-01)
袁俊傑
;
連俊龍
;
趙昌博
一種生物感測元件，包含基板、金屬傳導層、複數個工作電極以及絕緣層。金屬傳導層配置於基板之上，且金屬傳導層具有上表面。此些工作電極配置於金屬傳導層的上表面之上，其中各個工作電極包含一頂面，且各頂面高於金屬傳導層的上表面。絕緣層覆蓋金屬傳導層並圍繞此些工作電極，其中絕緣層之上表面介於此些頂面與金屬傳導層之上表面之間，使得此些工作電極凸出絕緣層之上表面。在此亦提供一種生物感測元件的製造方法，以及利用此生物感測元件進行生物分子檢測的方法。
Lake level changes in the Tibetan Plateau from Cryosat-2, SARAL, ICESat, and Jason-2 altimeters
(2019-02-01)
Hwang, Cheinway
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Cheng, Yung-Sheng
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Yang, Wan-Hsin
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Zhang, Guoqing
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Huang, Yong-Ruei
Lake level change in the Tibetan Plateau is an important indicator for regional and global climate changes. We use altimeter data from Cryosat-2, SARAL, ICESat, and Jason-2 to detect lake level changes at different spatial and temporal resolutions over 2003 - 2017 (Jason-3 data in 2017 for validation). Cryosat-2's SARIn mode provides precise water level time series over 59 lakes. SARAL's waveforms are retracked to generate near monthly, high-quality measurements at 31 lakes. Jason-2 provides a reference for removing inter-altimeter biases, enabling coherent records over lakes with Jason-2 passes. After a decade of rise since the ICESat record of 2003, the lake levels of Nam Co, Selin Co, Ngangzi Co, and Chibuzhang Co became flat in 2014 - 2016 and started to fluctuate or decline after 2016. Such positive-flat-negative trends are consistent with the trend variations of mass change from Gravity Recovery and Climate Experiment (GRACE). SARAL detected persistent lake level declines over 2013 - 2016 in southern Tibet that may signify the onset of decadal reduced flows of the Yarlung Tsangpo and Brahmaputra River that could affect the water supply for their downstream regions in India and Bangladesh. Cryosat-2 and Jason-2 detected sudden lake level rises and falls around Zhuonai, Kusai, and Salt Lake associated with a 2011 lake outburst, which is confirmed by lake volume changes from two Landsat-7 images. With a careful processing and calibration, multiple altimeters allow for determining and cross-validating long-term and episodic lake level changes unachievable by a single altimeter.
Improved Performance of Near UV GaN-Based Light Emitting Diodes With Asymmetric Triangular Multiple Quantum Wells
(2019-02-01)
Li, Heng
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Chang, Chia-Jui
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Kuo, Shiou-Yi
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Wu, Hao-Cheng
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Huang, Huamao
Near-ultraviolet (NUV) light-emitting diodes (LEDs) have been used in several potential applications such as UV curing and biochemical sensors. However, the internal quantum efficiency (IQE) of NUV-LEDs is still a crucial issue. To improve the IQE, in this paper, an asymmetric triangular multiple quantum well (MQW) structure was used, which exhibited a higher emission efficiency and lower efficiency droop with nitrogen face-oriented inclination. This is in contrast to the trend observed in blue LEDs. Furthermore, we demonstrated that holes are more confined in MQWs with nitrogen face-oriented inclination than in MQWs with gallium face-oriented inclination. Moreover, simulations revealed that the IQE improved by approximately 32% compared with that of symmetric square MQWNUV-LEDs; this trend was also confirmed through experimental results. The external quantum efficiency of thin-film flip-chip LEDs with nitrogen face-oriented inclination MQWs was 52%.
Changing Spectrum of Opportunistic Illnesses among HIV-Infected Taiwanese Patients in Response to a 10-Year National Anti-TB Programme
(2019-02-01)
Lee, Chun-Yuan
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Wu, Pei-Hua
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Lu, Po-Liang
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Tsai, Hung-Chin
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生醫工程研究所
The current trends and spectrum of acquired immunodeficiency syndrome (AIDS)-related opportunistic illnesses (AOIs) among newly diagnosed human immunodeficiency virus (HIV)-infected patients after the implementation of the 2006-2015 national anti-tuberculosis (TB) programmes in Taiwan remain unknown. We retrospectively reviewed 1757 patients at two centres in southern Taiwan between 2001 and 2015. Based on the anti-TB programme, patients were classified into periods 1 (2001-2005), 2 (2006-2010), and 3 (2011-2015). We further analysed factors associated with Mycobacterium tuberculosis (MTB) at presentation and during follow-up. The overall AOI incidence rate (23.6%) remained unchanged across the periods, with 81.4% of AOIs occurring at presentation. Pneumocystis jirovecii pneumonia was the leading AOI across the periods. MTB declined significantly from period 1 to period 3 (39.3% vs. 9.3%). Age and CD4+ cell count <200 cells/mu L (vs. >= 501) were the risk factors associated with MTB at presentation, whereas period 2/3 (vs. period 1) was the protective factor. Intravenous drug use (vs. homosexual contact) was the risk factor associated with MTB during follow-up, and period 3 (vs. period 1) was the protective factor. AOI statistics in Taiwan must be closely monitored for fluctuations. Although MTB decreased substantially after implementation of the anti-TB programmes, additional efforts to reduce MTB are required.
Detection of pesticide residues on intact tomatoes by carbon fiber ionization mass spectrometry
(2019-02-01)
Wu, Min-Li
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Wu, Yi-Cheng
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Chen, Yu-Chie
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應用化學系
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Department of Applied Chemistry
Trace and toxic pesticide residues may still remain on crops after harvest. Thus, maximum residual levels (MRLs) of pesticides on crops have been regulated. To determine whether the remaining pesticide residue level is below MRL, time-consuming sample pretreatment is needed prior to analysis of crop samples by suitable analytical tools. By elimination of sample pretreatment steps, a high-throughput method can be developed to determine the presence of pesticide residues directly on intact crops. Carbon fiber ionization mass spectrometry (CFI-MS) is effective in determining analytes with different polarities in solid, liquid, and vapor phases in open air. Moreover, the vapor derived from solid or liquid samples possessing high vapor pressure can be readily detected by CFI-MS. The setup of CFI-MS is straightforward. A carbon fiber (diameter of similar to 10m and length of similar to 1cm) is placed close (similar to 1mm) to the inlet of the mass spectrometer applied with a high voltage (-4.5kV). No direct electrical contact applied on the carbon fiber is required. When placing the sample with certain vapor pressure underneath the carbon fiber, analyte ions derived from the sample can be readily detected by the mass spectrometer. Given that most pesticides possess a certain vapor pressure (similar to 1.33x10(-5)-similar to 1.33x10(-4)Pa), we herein develop a qualitative and quantitative analysis method to determine pesticide residues on intact fruits such as tomato based on CFI-MS without requiring any sample pretreatment. Atrazine, ametryn, carbofuran, chlorpyrifos, isoprocarb, and methomyl were selected as model samples. Low limits of detection (at nM range) were achieved for the model pesticides using the current approach. Moreover, we demonstrated that the precision and accuracy of quantitative analysis of similar to 5% and similar to 2%, respectively, could be achieved using this approach.
A Low-Power, Differential Relaxation Oscillator With the Self-Threshold-Tracking and Swing-Boosting Techniques in 0.18-mu m CMOS
(2019-02-01)
Lu, Shao-Yung
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Liao, Yu-Te
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電機工程學系
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Department of Electrical and Computer Engineering
This paper presents a fully integrated, 8.2-MHz relaxation oscillator with a self-threshold-tracking loop and swing-boosting technique for improving its long-term frequency stability and noise performance. The proposed latch-based relaxation oscillator increases the transition speed to reduce the static power consumption. To decrease the process-voltagetemperature dependence, we propose a self-threshold-tracking loop to ensure that the transition point of the inverter-based comparator is set to a fixed ratio of the supply voltage. In addition, the comparator delay can be compensated by the tracking loop, relaxing the requirements of comparator power consumption. The design is implemented in a 0.18-mu m CMOS process. The design achieves a period jitter of 7.66 psrms, the phase noise of -109 dBc/Hz at an offset frequency of 100 kHz, and an Allan deviation noise floor of 1.56 ppm. The resultant figure of merit is 160.8 dBc/Hz, while only consuming 46.3 mu W. The power efficiency of the design is 5.6 kHz/nW. As for the supply sensitivity, the design achieves 0.9 %/0.1 V, which is 10x lower than the design with no compensation loop. The measured temperature coefficient of the proposed oscillators is 123 ppm/degrees C from -20 degrees C to 100 degrees C without any trimming process.
Rigid-Mass Vehicle Model for Identification of Bridge Frequencies Concerning Pitching Effect
(2019-02-01)
Yang, Judy P.
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Chen, Bo-Lin
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土木工程學系
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Department of Civil Engineering
The concept of vehicle-bridge interaction (VBI) was originally developed to investigate the dynamic behavior of bridges subjected to moving loads such as high-speed trains. In recent years, the VBI system was introduced to further explore the possibility of identifying bridge frequencies in order to monitor the health of bridges via the use of passing vehicles. Among the models of test vehicles, the sprung mass vehicle model with a single-degree-of-freedom vehicle body is the most common adopted one due to its simplicity. Nevertheless, for a test vehicle moving over the uneven pavement, the pitching effect arising from the vertical and rotational movements of the vehicle actually influences the identification of bridge frequencies. As such, a rigid-mass vehicle model is proposed in this work to improve the sprung mass vehicle model by including both vertical and rotational deflections. The analytical solutions to the rigid-mass VBI system are derived to verify the proposed model, and the numerical examples are provided to investigate the dynamic behavior of the VBI system subjected to road irregularity.
Hardware-Based Courseware for Teaching the Theory of Transmission Lines
(2019-02-01)
Tsai, Zuo-Min
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Wang, Yu-Syuan
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交大名義發表
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National Chiao Tung University
This article presents a hardware-based courseware package for use in teaching transmission line (Tline) theory. The hardware components include large inductors and capacitors that are used to slow down the speed of signals in the Tline and LEDs to allow the slowed-down signals to be observed by the human eye. This courseware can be used to augment the laboratory work in electromagnetic courses that teach Tline theory or for experimentation in microwave circuits, such as open/short stubs, branch line couplers, or Wilkinson dividers. A workshop was conducted to collect feedback on the proposed courseware from students after they had received instruction in Tline theory using both software-based and the proposed hardware-based courseware. In their feedback, the majority of students expressed more interest in the proposed hardware-based courseware than in the conventional software-based courseware.
Junctionless gate-all-around nanowire field-effect transistors with an extended gate in biomolecule detection
(2019-02-01)
Chen, Chih-Wei
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Lin, Ru-Zheng
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Chiang, Li-Chuan
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Pan, Fu-Ming
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Sheu, Jeng-Tzong
In this study, we investigated the potential drift and sensitivity in an extended-gate (EG) field-effect-transistor (FET)-based potentiometric sensor with junctionless (JL) and inversion-mode (IM) gate-all-around (GAA) nanowire (NW) FETs. An EG electrode (EGE) coated with Al2O3 via plasmaenhanced atomic-layer deposition exhibited high stability. Both JL and IM GAA NWFETs were prepared in the same batch and exhibited high electrical performance, including a steep subthreshold swing of approximately 63 mV dec(-1) and a high ON/OFF current ratio of approximately 3 x 10(7) at V-DS = 0.1 V. However, JL GAA NWFETs exhibited higher drift stability than did IM GAA NWFETs under various working regions over a long period of operation. Furthermore, JL GAA NWFETs with EGEs (JL GAA NWFETs w-EGEs) exhibited the highest sensitivity when operating under the subthreshold region in pH sensing (Delta I/I-0 = similar to 4410%). The readout sensitivity reached S-out = 82%. A JL GAA NWFET w-EGE was also demonstrated as a potentiometric biosensor for streptavidin real-time detection at concentrations of 42 fM to 4.2 nM. (C) 2019 The Japan Society of Applied Physics
A Partial-Consensus Posterior-Aggregation FAHP Method-Supplier Selection Problem as an Example
(2019-02-01)
Wang, Yu-Cheng
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Chen, Tin-Chih Toly
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工業工程與管理學系
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Department of Industrial Engineering and Management
Existing fuzzy analytic hierarchy process (FAHP) methods usually aggregate the fuzzy pairwise comparison results produced by multiple decision-makers (DMs) rather than the fuzzy weights estimations. This is problematic because fuzzy pairwise comparison results are subject to uncertainty and lack consensus. To address this problem, a partial-consensus posterior-aggregation FAHP (PCPA-FAHP) approach is proposed in this study. The PCPA-FAHP approach seeks a partial consensus among most DMs instead of an overall consensus among all DMs, thereby increasing the possibility of reaching a consensus. Subsequently, the aggregation result is defuzzified using the prevalent center-of-gravity method. The PCPA-FAHP approach was applied to a supplier selection problem to validate its effectiveness. According to the experimental results, the PCPA-FAHP approach not only successfully found out the partial consensus among the DMs, but also shrunk the widths of the estimated fuzzy weights to enhance the precision of the FAHP analysis.
Lateral Movement Decision Model for Powered Two-Wheelers in Taiwan
(2019-02-01)
Dong, Han
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Chen, Yen-Yu
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Cirillo, Cinzia
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Wong, K., I
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運輸與物流管理系註：原交通所+運管所
The maneuvering of powered two-wheelers (PTWs) is non-lane-based, and the interactions between PTWs and other vehicles in mixed traffic are complex. The behavior of PTWs, particularly in developing countries, is not the same as that of passenger cars, which has been studied for several decades. This study contributes to the existing literature on PTWs in several ways. A real-world microscopic vehicle trajectory database has been digitalized from a video clip for a four-lane urban arterial in Taipei (Taiwan). From a modeling perspective, a dynamic discrete choice model is proposed to capture the lateral-shifting behaviors of PTWs in mixed traffic conditions. The model considers not only the positions of all surrounding vehicles but also riders' perception of expected traffic conditions. The behavioral model is able to describe the sequential non-lane-based maneuvers of PTWs, including not following lane discipline, filtering, moving abreast of other vehicles in the same lane, oblique following, swerving, and overtaking from the same lane. The results indicate that a better model fit is obtained when taking into account the dynamic nature of the problem. The data and methods proposed have the potential to improve microscopic traffic simulation of mixed traffic with a large amount of PTWs. Practical applications are concerned with the improvement of road geometries and the definition of control strategies for mixed traffic flows.