Browsing by Issue Date, starting with "2015-09-02"

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Time-periodic solutions of the primitive equations of large-scale moist atmosphere: existence and stability
(2015-09-02)
Hsia, Chun-Hsiung
;
Shiue, Ming-Cheng
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數學建模與科學計算所(含中心)
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Graduate Program of Mathematical Modeling and Scientific Computing, Department of Applied Mathematics
This article is devoted to the study of the asymptotic stability of the three-dimensional viscous primitive equations for large-scale moist atmosphere in the pressure coordinate system. An asymptotic stability criterion for the solutions of such model with time-dependent forcing terms is obtained. In particular, under the assumptions that the associated forces are both time-periodic and small (in a suitable sense), we obtain the existence of the time-periodic solution for the primitive equations of large-scale moist atmosphere. Moreover, this time-periodic solution is asymptotically stable in L-2 sense.
Non-symmetrical liquid crystal dimers armed with azobenzene and 1,2,3-triazole-cholesterol
(2015-09-02)
Alshargabi, Arwa
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Yeap, Guan-Yeow
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Mahmood, Wan Ahmad Kamil
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Han, Chun-Chieh
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Lin, Hon-Cheu
New non-symmetrical dimers which contain respective side units of azobenzene and 1,2,3-triazole-choloesteral have been synthesised from the reaction between 6-azido-[4-(4-acetylphenylazo)phenoxy]alkane and cholesteryl-4-(prop-2-ynyloxy)benzoate. The results show that the derivatives of 6-bromo[4-(4-acetylphenylazo)phenoxy]alkanes which possess the odd alkyl spacers exhibit dimesomorphism of N and SmA phases whilst the members with even numbers are non-mesogenic. However, the 6-azido-[4-(4-acetylphenylazo)phenoxy]-alkanes show N and SmA phases in a wide temperature range. On heating and cooling the target compounds cholesteryl 4-[(1-(6-(4-(4\'-acetylphenylazo)phenoxy)alkyl)-1H-1,2,3-triazol-4-yl)methoxy]benzoate show chiral nematic (oily streak and fan-shaped texture) and focal conic texture characteristics of smectic A phases with high thermal stability. Present investigation also reveals the effect of the spacer length upon the phase transition temperature. Intercalated arrangement is favoured by the molecules in the smectic phase. The observation is well established by XRD measurement wherein the actual molecular length is smaller than the theoretical value.
New Synthesis Route of Hydrogel through A Bioinspired Supramolecular Approach: Gelation, Binding Interaction, and in Vitro Dressing
(2015-09-02)
Cheng, Chieh
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Tang, Meng-Che
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Wu, Chung-Shu
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Simon, Turibius
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Ko, Fu-Hsiang
Peptide-based supramolecular hydrogels have been comprehensively investigated in biomaterial applications because of their unique bioactivity, biofunctionality, and biocompatible features. However, the presence of organic building blocks in peptide-based hydrogels often results in low mechanical stability. To expand their practical use and range of applications, it is necessary to develop the tool kit available to prepare bioinspired, peptide-based supramolecular hydrogels with improved mechanical stability. In this paper, we present an innovative electrostatic and cross-linking approach in which naphthyl-Phe-Phe-Cys (NapFFC) oligopeptides are combined with gold nanoparticles (AuNPs) and calcium ions (Ca2+) to produce peptide-based supramolecular hydrogels. We further investigate the interactions among NapFFC, AuNPs and Ca" by microscopy. The morphology of the nanofibrous network constructions and the binding forces exhibited from the hydrogel demonstrated that the combination of two mechanisms successfully enhanced the mechanical stability through the formation of a densely entangled fibrous network of peptide multimers that is attributed to the AuNP linkage and Ca2+-induced agglomeration. UV vis spectrophotometry and fluorescence analysis were also used to demonstrate the enhanced stability of the hydrogel under various conditions such as thermal, solvent erosion, pH value and sonication. All results indicate that the presence of AuNPs and Ca2+ can strengthen the prepared hydrogel by more than doubling the diameter of NapFFC nanofibers, enabling the formation of stronger frameworks and slowing the release of components. Further experiments confirmed that HeLa cells can grow on the bioinspired NapFFC-AuNP hydrogel and exhibit high cell viability and that these cells were killed on contact with a hydrogel containing a drug. Our peptide-based supramolecular hydrogels prepared from the observed electrostatic and cross-linking mechanisn exhibited a significantly improved mechanical stability, making them well suited to use as a drug carrier in hydrogel dressings and as extracellular materials (ECMs) for tissue engineering.
Update on infections caused by Stenotrophomonas maltophilia with particular attention to resistance mechanisms and therapeutic options
(2015-09-02)
Chang, Ya-Ting
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Lin, Chun-Yu
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Chen, Yen-Hsu
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Hsueh, Po-Ren
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生醫工程研究所
Stenotrophomonas maltophilia is a Gram-negative, biofilm-forming bacterium. Although generally regarded as an organism of low virulence, S. maltophilia is an emerging multi-drug resistant opportunistic pathogen in hospital and community settings, especially among immunocompromised hosts. Risk factors associated with S. maltophilia infection include underlying malignancy, cystic fibrosis, corticosteroid or immunosuppressant therapy, the presence of an indwelling central venous catheter and exposure to broad spectrum antibiotics. In this review, we provide a synthesis of information on current global trends in S. maltophilia pathogenicity as well as updated information on the molecular mechanisms contributing to its resistance to an array of antimicrobial agents. The prevalence of S. maltophilia infection in the general population increased from 0.8-1.4% during 1997-2003 to 1.3-1.68% during 2007-2012. The most important molecular mechanisms contributing to its resistance to antibiotics include beta-lactamase production, the expression of Qnr genes, and the presence of class 1 integrons and efflux pumps. Trimethoprim/sulfamethoxazole (TMP/SMX) is the antimicrobial drug of choice. Although a few studies have reported increased resistance to TMP/SMX, the majority of studies worldwide show that S. maltophilia continues to be highly susceptible. Drugs with historically good susceptibility results include ceftazidime, ticarcillin-clavulanate, and fluoroquinolones; however, a number of studies show an alarming trend in resistance to those agents. Tetracyclines such as tigecycline, minocycline, and doxycycline are also effective agents and consistently display good activity against S. maltophilia in various geographic regions and across different time periods. Combination therapies, novel agents, and aerosolized forms of antimicrobial drugs are currently being tested for their ability to treat infections caused by this multi-drug resistant organism.
Self-Assembled Epitaxial Core-Shell Nanocrystals with Tunable Magnetic Anisotropy
(2015-09-02)
Liao, Sheng-Chieh
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Chen, Yong-Lun
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Kuo, Wei-Cheng
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Cheung, Jeffrey
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Wang, Wei-Cheng
Large-Area Nano-patterning and Fabrication of Vertical Transistor Array by Non-close-packed Polystyrene Spheres
(2015-09-02)
Chen, Yen-Ming
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Lai, Yu-Yen
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Chao, Yu-Chiang
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
We demonstrated a large-area nanopatterning technique with the help of a non-close-packed PS sphere layer over a large-area substrate. The non-close-packed PS sphere layer is fabricated by blade coating method. It was demonstrated that non-close-packed PS spheres can be achieved within an area of 18 cm x 25 cm on a rigid glass substrate and within an area of 10 cm x 10 cm on a flexible substrate. We also demonstrated that the blade-coated non-close-packed PS sphere layer was suitable for the mass production of vertical organic transistors over a large area.
Locating System for Locking Hole of Intramedullary Nail
(2015-09-03)
Lee Meng-Shiue
;
Wu Sung-Yueh
;
Hsu Wensyang
;
Wong Tze-Hong
;
Chung Tien-Kan Chung
The present invention discloses a two-stage locating device and the method thereof. In stage-one, the preliminary locating device finds the approximate area of the locking hole encircled with the magnetic material on the intramedullary nail. In stage-two, the pinpoint device has a plurality of targeting devices and includes a transparent plate with a plurality of alignment lines. According to the deviations between each pointing device and the alignment lines, the direction of the pinpoint device for further adjustment can be determined. The present invention can determine the position and the orientation of the locking hole on the intramedullary nail quickly and precisely to shorten the time spent to implant the intramedullary nail. Furthermore, the present invention can also have a conductive circuit to connect to an alarm device. Thus, the precise location can be determined through the different alarm signals based on the contact conditions between each directing devices and the conductive circuit.
Effect of cell integrity on algal destabilization by oxidation-assisted coagulation
(2015-09-04)
Lin, Jr-Lin
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Huang, Chihpin
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Wang, W. M.
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環境工程研究所
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Institute of Environmental Engineering
A hybrid oxidation-coagulation process is commonly adopted to destabilize algae and subsequently improve the removal of algae from water through sedimentation and filtration in water treatment plants (WTPs). Preoxidation is crucial to improving algae removal by a coagulation-sedimentation process. The goal of this study was to investigate the effect of oxidation with NaOCl and ClO2 on the cell integrity of algae (i.e. diatoms) and the destabilization of algae by means of Alum coagulation. The effects of oxidation-assisted coagulation on the performance of sedimentation as well as filtration were evaluated. The results show that ClO2 reduces cell integrity more severely than NaOCl during oxidation. The degradation of chlorophyll a and humic-like substances generated by cells ruptured by ClO2 oxidation is stronger than that by NaOCl oxidation. During oxidation both NaOCl and ClO2 fail to cause significant cell lysis, while cell settleability can be improved markedly by using only ClO2. Preoxidation with ClO2 is more effective in destabilizing the particles and algae when applying Alum coagulation at low dosages. It was found that the residual algae counts in the supernatants are inversely well-correlated to its filterability instead of its residual turbidity. The reduced cell integrity resulting from ClO2 preoxidation effectively improves the performance of coagulation-sedimentation for algae (diatoms) removal and reduces the burden of filtration operation in the WTPs. (C) 2015 Elsevier B.V. All rights reserved.
Matrix metalloproteinase 2 level in human follicular fluid is a reliable marker of human oocyte maturation in in vitro fertilization and intracytoplasmic sperm injection cycles
(2015-09-04)
Yang, Wen-Jui
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Liu, Fon-Chang
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Hsieh, Jih-Sheng
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Chen, Ching-Hung
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Hsiao, Shun-Yu
Background: To determine whether matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMP-1 and TIMP-2) in human follicular fluid, have any relationships with oocyte maturation in vivo and subsequent fertilization during in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles. Methods: The follicular fluids were obtained from 150 female patients undergoing IVF/ICSI cycles and a total of 1504 oocytes were retrieved for analysis. MMP-2 and MMP-9 activities were measured using zymography assay. TIMP-1 and TIMP-2 concentrations were quantitatively assessed using enzyme-linked immunosorbent assay (ELISA). Results: Human follicular fluid MMP-2 level was significantly associated with the rate of maturity of oocytes (P < 0.001). Furthermore, the MMP-2 was significantly associated with the higher fertilization rate (P < 0.01). There was no significant correlation between follicular MMP-9 and the maturation rate of oocytes. The TIMP-1 and TIMP-2 also showed no correlation with the oocyte maturation rate. Conclusions: The level of gelatinase MMP-2 in human follicular fluid might be a reliable marker of mature oocytes during IVF/ICSI cycles. Furthermore, the MMP-2 expression has a strong association with higher fertilization rate. Further studies are needed to support this theory.
Laminar shear flow increases hydrogen sulfide and activates a nitric oxide producing signaling cascade in endothelial cells
(2015-09-04)
Huang, Bin
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Chen, Chang-Ting
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Chen, Chi-Shia
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Wang, Yun-Ming
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Hsieh, Hsyue-Jen
Laminar shear flow triggers a signaling cascade that maintains the integrity of endothelial cells (ECs). Hydrogen sulfide (H2S), a new gasotransmitter is regarded as an upstream regulator of nitric oxide (NO). Whether the H2S-generating enzymes are correlated to the enzymes involved in NO production under shear flow conditions remains unclear as yet. In the present study, the cultured ECs were subjected to a constant shear flow (12 dyn/cm(2)) in a parallel flow chamber system. We investigated the expression of three key enzymes for H2S biosynthesis, cystathionine-gamma-Iyase (CSE), cystathionine-beta-synthase (CBS), and 3-mercapto-sulfurtransferase (3-MST). Shear flow markedly increased the level of 3-MST. Shear flow enhanced the production of H2S was determined by NBD-SCN reagent that can bind to cysteine/homocystein. Exogenous treatment of NaHS that can release gaseous H2S, ECs showed an increase of phosphorylation in Akt(S473), ERKT202/Y204 and eNOS(S1177). This indicated that H2S can trigger the NO-production signaling cascade. Silencing of CSE, CBS and 3-MST genes by siRNA separately attenuated the phosphorylation levels of Akt(S423) and eNOS(S1177) under shear flow conditions. The particular mode of shear flow increased H2S production. The interplay between H2S and NO-generating enzymes were discussed in the present study. (C) 2015 Elsevier Inc. All rights reserved.
Investigation of the semi-dimple vortex generator applicable to fin-and-tube heat exchangers
(2015-09-05)
Wang, Chi-Chuan
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Chen, Kuan-Yu
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Lin, Yur-Tsai
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機械工程學系
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Department of Mechanical Engineering
The present study examines the air side performance of the fin-and-tube heat exchangers having semi-dimple vortex generator or plain fin geometry. A total of eight samples are made and tested with the corresponding fin pitch (F-P) being 1.6 mm and 2.0 mm and the number of tube row (N) are 1 and 2. The inlet air flow direction is also being tested upon the proposed semi-dimple VG. Test results indicate that the heat transfer performance of the proposed semi-dimple VG with N = 1 at a smaller fin pitch of 1.6 mm is slightly higher than that of plain fin geometry. For N = 1 with a larger fin pitch of 2.0 mm, the semi-dimple VG is about 10% higher than that of plain fin geometry. The difference in heat transfer performance amid VG and plain fin geometry becomes more pronounced with N = 2 and is especially evident when F-P = 2.0 mm due to mixing contribution. In general, the difference between plain and semi-dimple geometry becomes more conspicuous at a larger fin pitch because of the comparatively effectively swirled motion. Both geometries show a dependence on fin pitch at N = 1 but the effect is almost negligible when N is increased to 2. The inlet air flow direction casts negligible influence on the heat transfer performance of semi-dimple VG. However, the friction factors for the opposite air flow operation is lower than that of normal operation, especially in low Reynolds number region. (C) 2014 Elsevier Ltd. All rights reserved.
交大e-News第193期-績優導師專題故事
(2015-09-07)
國立交通大學秘書室
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Secretariat
4.8 Gbit/s 16-QAM-OFDM transmission based on compact 450-nm laser for underwater wireless optical communication
(2015-09-07)
Oubei, Hassan M.
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Duran, Jose R.
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Janjua, Bilal
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Wang, Huai-Yung
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Tsai, Cheng-Ting
We experimentally demonstrate an underwater wireless optical communications (UWOC) employing 450-nm TO-9 packaged and fiber-pigtailed laser diode (LD) directly encoded with an orthogonal frequency division multiplexed quadrature amplitude modulation (QAM-OFDM) data. A record data rate of up to 4.8 Gbit/s over 5.4-m transmission distance is achieved. By encoding the full 1.2-GHz bandwidth of the 450-nm LD with a 16-QAM-OFDM data, an error vector magnitude (EVM) of 16.5%, a signal-to-noise ratio (SNR) of 15.63 dB and a bit error rate (BER) of 2.6 x 10-3, well pass the forward error correction (FEC) criterion, were obtained. (C) 2015 Optical Society of America
Solvent-Induced Dewetting on Curved Substrates: Fabrication of Porous Polymer Nanotubes by Anodic Aluminum Oxide Templates
(2015-09-08)
Chi, Mu-Huan
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Chang, Chun-Wei
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Ko, Hao-Wen
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Su, Chun-Hsien
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Lee, Chih-Wei
Dewetting of polymer thin films triggered by thermal or solvent annealing on flat substrates have been widely studied. Research on dewetting of polymer thin films on curved substrate, however, has been rarely investigated and remains a great challenge, especially for dewetting induced by solvent annealing. In this work, we study the dewetting of polymer thin films on curved substrates by annealing poly(methyl methacrylate) (PMMA) nanotubes in cylindrical nanopores of anodic aluminum oxide (AAO) templates via dimethylformamide (DMF) vapor treatment. After solvent annealing, dewetting of the curved PMMA thin films is induced, resulting in the formation of porous PMMA nanotubes. By changing the experimental conditions such as annealing time, solvent quality, and molecular weight of polymer, the hole sizes of the PMMA nanotubes can be controlled or even prevented. To demonstrate the universality of this method, porous nanotubes of polystyrene (PS) and fluorescent pyrene-ended PMMA (Py-PMMA) are also fabricated. This work not only provides a better understanding of dewetting of polymer thin films on curved substrates but also offers a promising new way to prepare porous polymer nanotubes with controllable hole sizes.
Impacts of high-electroactive-surface-area buckypaper counter electrodes on the photovoltaic performance of dye-sensitized solar cells
(2015-09-09)
Cheng, Cheng-En
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Lin, Yu-Chang
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Tsai, Shang-Yi
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Lin, Zheng-Kun
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Lee, Ping-Chen
In this paper we study the photovoltaic performance of dye-sensitized solar cells (DSCs) with high-electroactive-surface-area buckypaper (BP) counter electrodes (CEs). BP is made of entangled multi-walled carbon nanotubes and has a high electroactive surface area, which is effectively 11.5 times higher than that of Pt. The high surface area of BP causes a high I-3(-) reduction rate at the CEs and suppresses the charge recombination at the anodes. Accordingly, the open-circuit voltage, the filling factor, and the power conversion efficiency of DSCs with BP CEs are enhanced, and these photovoltaic parameters exhibit a better trend with the increase of solar power compared with conventional DSCs with Pt CEs.
Switching Kinetic of VCM-Based Memristor: Evolution and Positioning of Nanofilament
(2015-09-09)
Chen, Jui-Yuan
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Huang, Chun-Wei
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Chiu, Chung-Hua
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Huang, Yu-Ting
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Wu, Wen-Wei
The filament in a Au/Ta2O5/Au system is analyzed and determined to be a nanoscaled TaO2-x filament. A shrunken anode localizes the filament formation and the defect boundary leads to faster accumulation of oxygen vacancies. The defect changes the switching domination between electron transport and oxygen-vacancy migration. The migration of oxygen vacancies limits the filament dynamics, indicating the crucial role played by oxygen defects.
CONSTANT TRANSCONDUCTANCE BIAS CIRCUIT
(2015-09-10)
Wang Yu-Jiu
;
CHU Ching-Yun
A bias circuit is adapted for biasing a to-be-biased transconductance cell such that the to-be-biased transconductance cell has a constant transconductance, and includes a converter and a controller. The converter receives first and second current signals, and generates, based on the first and second current signals, a first voltage signal, a second voltage signal and a bias voltage that is for biasing the to-be-biased transconductance cell. The controller receives the first and second voltage signals from the converter, generates the first and second current signals for the converter based on the first and second voltage signals so as to make a magnitude of the first voltage signal equal a magnitude of the second voltage signal.
Neural interfaces with electrically controllable delivery of manganese ions applied for MEMRI-functionalized deep brain stimulation
(2015-09-10)
Huang, Wei-Chen
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Lo, Yu-Chin
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Chen, You-Yin
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Chen, San-Yuan
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材料科學與工程學系
Single Molecule Take-and-Place Technique for Positioning a Membrane Protein on a Lipid Bilayer
(2015-09-10)
Liu, Tseng-Huang
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Huang, Yun-Tzu
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Cheng, Hui-Wen
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Chen, Yen-Wei
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Lee, Ching-Hung
Manipulating a single protein molecule on liposomes or planar lipid bilayers is a useful technique for studying membrane-bound proteins, receptors, or ion transporters and for delicate applications including biosensor chips, drug screening, and clinical diagnoses. However, several key breakthroughs are required for success through difficult techniques such as single protein take-and-place with reasonable spatiotemporal control. In this report, a novel method was established for placing a single transmembrane protein onto a patterned lipid bilayer. A surface-functionalized 1.8 nm gold nanoparticle was first engineered at the tip of an atomic force microscope. A single transmembrane protein, H+-translocating pyrophosphatase with six-histidine residues tag, was then picked up using such a microscopy tip where its nanoparticle was modified by nickel-nitrilotriacetic acid. Two-step fluorescence bleaching observation and quantum dot blinking analysis subsequently verified successful manipulation of a single functional protein on a lipid membrane in a predetermined manner. Furthermore, the enzymatic activity from the single H+-translocating pyrophosphatase was determined, demonstrating that membrane proteins retain their functions on the lipid bilayer through a single-molecule take-and-place technique. This innovative technique overcomes current limitations and provides a single biomolecule nanomanipulation system for versatile studies of membrane-bound proteins.
New Measurement of Antineutrino Oscillation with the Full Detector Configuration at Daya Bay
(2015-09-11)
An, F. P.
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Balantekin, A. B.
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Band, H. R.
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Bishai, M.
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Blyth, S.
We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9 x 10(5) GW(th) ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six Am-241-C-13 radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin(2)2 theta(13) and vertical bar Delta m(ee)(2)vertical bar were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin(2)2 theta(13) = 0.084 +/- 0.005 and vertical bar Delta m(ee)(2)vertical bar = (2.42 +/- 0.11) x 10(-3) eV(2) in the three-neutrino framework.