Browsing by Issue Date, starting with "2010-02-05"

Now showing 1 - 20 of 46893

Alteration of the Substrate's Prefolded Conformation and Cyclization Stereochemistry of Oxidosqualene-Lanosterol Cyclase of Saccharomyces cerevisiae by Substitution at Phenylalanine 699
(2010-02-05)
Wu, Tung-Kung
;
Chang, Cheng-Hsiang
;
Wen, Hao-Yu
;
Liu, Yuan-Ting
;
Li, Wen-Hsuan
The Saccharomyces cerevisiae ERG7(Phe699) mutants produced one chair-chair-chair (C-C-C) and two chair-boat-chair (C-B-C) truncated tricyclic compounds, one tetracyclic 17 alpha-exocyclic unrearranged intermediate, and two 17 beta-exocyclic truncated rearranged intermediates. These results provided direct evidence for the importance of the residue in affecting mechanistic transitions between C-B-C and C-C-C substrate conformation and between the 17 alpha- and 17 beta-exocyclic side chain stereochemistry as well as in stabilizing the 6 -6-5 tricyclic and the protosteryl C-17 cations.
A potential role for Helicobacter pylori heat shock protein 60 in gastric tumorigenesis
(2010-02-05)
Lin, Chen-Si
;
He, Pei-Juin
;
Tsai, Nu-Man
;
Li, Chi-Han
;
Yang, Shang-Chih
Helicobacter pylon has been found to promote the malignant process leading to gastric cancer. Heat shock protein 60 of H. pylori (HpHSP60) was previously been identified as a potent immunogene. This Study investigates the role of HpHSP60 in gastric cancer carcinogenesis. The effect of HpHSP60 on cell proliferation, anti-death activity, angiogenesis and cell migration were explored. The results showed that HpHSP60 enhanced migration by gastric cancer cells and promoted tube formation by umbilical vein endothelial cells (HUVECs); however, HpHSP60 did not increase cell Proliferation nor was this protein able to rescue gastric cancer cells from death. Moreover, the results also indicated HpHSP60 had different effects on AGS gastric cancer cells or THP-1 monocytic cells in terms of their expression of pro-inflammatory cytokines, which are known to be important to cancer development. We propose that HpHSP60 may trigger the initiation of carcinogenesis by inducing pro-inflammatory cytokine release and by promoting angiogenesis and metastasis. Thus, this extracellular pathogen-derived HSP60 is potentially a vigorous virulence factor that can act as a carcinogen during gastric tumorigenesis. (C) 2010 Elsevier Inc. All rights reserved.
Highly efficient flexible inverted organic solar cells using atomic layer deposited ZnO as electron selective layer
(2010-02-07)
Wang, Jen-Chun
;
Weng, Wei-Tse
;
Tsai, Meng-Yen
;
Lee, Ming-Kun
;
Horng, Sheng-Fu
Determination of the microstructure of Eu-treated ZnO nanowires by x-ray absorption
(2010-02-08)
Huang, W. L.
;
Labis, J.
;
Ray, S. C.
;
Liang, Y. R.
;
Pao, C. W.
X-ray absorption near-edge structure (XANES), extended x-ray absorption fine structures (EXAFS), and photoluminescence measurements were used to elucidate the microstructural and photoluminescence properties of ZnO nanowires (ZnO-NWs) that had been treated with Eu by thermal diffusion. The O K- and Eu L(3)-edge XANES and EXAFS spectra at the Zn K- and Eu L(3)-edge verified the formation of Eu(2)O(3)-like layer on the surface of ZnO-NWs. X-ray diffraction, XANES and EXAFS measurements consistently suggest the lack of substitutional doping of Eu ions at the Zn ion sites in the interior of ZnO-NWs. The clear sharp and intense emission bands in the range 610-630 nm of Eu-treated ZnO-NWs originated from the intra-4f transition of Eu ions in the Eu(2)O(3)-like surface layer.
Novel Supramolecular Side-Chain Banana-Shaped Liquid Crystalline Polymers Containing Covalent- and Hydrogen-Bonded Bent bores
(2010-02-09)
Wang, Ling-Yung
;
Tsai, Hsin-Yi
;
Lin, Hong-Cheu
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Novel supramolecular side-chain banana-shaped liquid crystalline (LC) polymer complexes AmBn-N bearing various (m/n) molar ratios of hydrogen- and covalent-bonded bent-core components were acquired by the free radical polymerization, where the hydrogen-bonded (H-bonded) structures were executed via mixing equimolar portions of proton donor (H-donor) polymers AmBn (homopolymers/copolymers) and pyridyl proton acceptor (H-acceptor) bent cores (small molecules). The influences of the molar ratios of bent-core H-bonded components in side-chain banana-shaped LC polymers and their corresponding polymer complexes on mesomorphic and electro-optical properties were first investigated. The voltage-dependent antiferroelectric properties of spontaneous polarization (Ps) values in the polar smectic phase of the supramolecular side-chain banana-shaped copolymers were also reported. The nematic and tilted smectic phases were verified by XRD measurements, and the SmCp phase was further confirmed by the triangular wave method. Suprinsingly, a novel enantiotropic polar smectic (SmCP(A)) phase was generated in some bent-core side-chain polymer complexes AmBn-N. Therefore, a special approach to constructing (or stabilizing) the SmCP phase was first developed in this study by copolymerization of bent-core covalent - and H-bonded units in side-chain polymer complexes (with proper m/n molar ratios of 16/1 and 10/1 from both bent-core covalent- and H-bonded monomers (i.e., B and A-N units, respectively) without the SmCP phase.
Synthesis and Assembly Behavior of Heteronucleobase-Functionalized Poly(epsilon-caprolactone)
(2010-02-09)
Lin, I-Hong
;
Cheng, Chih-Chia
;
Yen, Ying-Chieh
;
Chang, Feng-Chih
;
應用化學系
The heteronucleobase (adenine and uracil)-functionalized poly(epsilon-caprolactone) (A-PCL-U) possessing supramolecular structure has been successfully synthesized through the combination of ring-opening polymerization and Michael addition reaction. Attachment of multiple hydrogen-bonding units to chain ends of PCL results in phase separation and substantial increase in the viscosity. The association constant (K(a)) between adenine and uracil groups of A-PCL-U calculated from NMR measurement is 18.9 M(-1). XRD and DSC analyses indicate that the crystalline structure of the A-PCL-U is changed to some extent due to phase segregation as compared to the PCL homopolymer. The AFM micrograph demonstrates that phase segregation is formed from the hard nucleobase chain ends and soft poly(epsilon-caprolactone) chains of the supramolecular complex.
跨越障礙之載具
(2010-02-11)
鄭璧瑩
;
郭芳富
;
黃健寶
;
林奕仲
;
李育賢
本發明係提供一種跨越障礙之載具，係用於載運乘客或其他負荷的支座；一感測調整模組用於偵測該支座傾斜之狀態與維持該支座之水平；一地面接觸模組，設置於該支座下，其支撐一有效載重，並可抬舉該支座跨越一障礙之一表面，與一無線訊號接收發射模組做結合，可藉由該無線訊號接收發射器蒐集與傳送資訊，來做出相對應其內部狀況所須之調整與動作，達成一具有安全、穩定、可靠、舒適、便利、成本低的跨越障礙之載具。【創作特點】本發明之主要目的係提供一種跨越障礙之載具，其係整合地面接觸模組、感測調整模組與無線訊號接收發射模組，以提高跨越障礙之載具之安全、穩定性、便利性。本發明之另一目的係提供一種跨越障礙之載具，係利用地面接觸模組的作動方式，以減少載具行進時所需之扭矩，降低其成本。本發明之再一目的係提供一種跨越障礙之載具，應用感測調整模組，使支座具有多向性水平控制、偵測、調整傾斜之功能。本發明之又一目的係提供一種跨越障礙之載具，與無線訊號接收發射模組結合，及時的監控與提升行動預測的準確性，以達到使用者即時的便利性。為達到上述之目地，本發明係提供一種跨越障礙之載具，其結構係包括一用於載運乘客或其他負荷的支座；與支座相接的一感測調整模組來偵測、維持支座之水平狀態，在支座下有一地面接觸模組，用來支撐該有效載重，藉由地面接觸元件繞著旋轉軸之轉動可抬舉此支座跨越一障礙之一表面；在利用裝設在跨越障礙之載具上的無線訊號接收發射模組，來蒐集與傳送資訊，使其做出相對應內部狀況所須之調整與動作，以強化該載具之安全性，及提昇載具與環境互動性，給予使用者更寬廣的無障礙空間。底下藉由具體實施例配合所附的圖式詳加說明，當更容易瞭解本發明之目的、技術內容、特點及其所達成之功效。
Reciprocating and Directed Motion on the Nanoscale: A Simple Kinetic Model
(2010-02-11)
Rozenbaum, V. M.
;
Makhnovskii, Yu. A.
;
Yang, D. -Y.
;
Sheu, S. -Y.
;
Lin, S. H.
We consider noise-induced reciprocating motion on the nanoscale and its rectification to directed motion using a simple model in which transitions between two fluctuating states occur through two reaction channels with fluctuating transition rates. The fluctuations of states and transition rates arise from equilibrium thermal and external nonthermal noise which is in either case position-dependent. The model is equivalent to a Brownian particle hopping in a periodic double-well potential which randomly switches between two profiles. With a nonequilibrium noise, a generalized driving force may be regarded as the sum of two forces: one resulting from energy fluctuations and the other from fluctuations of the spatial dependence of the transition rates. This suggests two mechanisms, energetic and informational, by which the motion occurs. The reciprocating motion results in directed motion if rectified by asymmetric fluctuations of potential barriers. The energy conversion efficiency is calculated and the conditions to maximize it are established.
Theoretical studies of ZEKE spectroscopy and dynamics of high Rydberg states
(2010-02-12)
Wang, Yi-Hsieh
;
Teranishi, Y.
;
Mineo, H.
;
Chao, S. D.
;
Selzle, H. L.
A main purpose of this Letter is to show how to employ the inverse Born-Oppenheimer approximation as a basis set to study zero kinetic energy (ZEKE) spectroscopy and the autoionization dynamics of the ZEKE states. The calculations of channel couplings, quantum defects, intensity borrowing, vibrational and rotational autotionizations will be demonstrated by using a homonuclear diatomic molecule as an example. (C) 2010 Elsevier B. V. All rights reserved.
白色発光蛍光体およびその発光装置
(2010-02-12)
陳登銘
;
張峻魁
【課題】化学式を(M1-m-nCem Eun)3Al2O5X2とする蛍光体を提供する。【解決手段】MはCa、SrおよびBaにより構成される群のうちの少なくとも1つから選ばれ、XはClおよびBrにより構成される群のうちの少なくとも1つから選ばれ、うち0＜m＜1、0＜n＜1とする。【選択図】図２
A structure-preserving doubling algorithm for quadratic eigenvalue problems arising from time-delay systems
(2010-02-15)
Li, Tie-Xiang
;
Chu, Eric King-wah
;
Lin, Wen-Wei
;
應用數學系
;
Department of Applied Mathematics
We propose a structure-preserving doubling algorithm for a quadratic eigenvalue problem arising from the stability analysis of time-delay systems. We are particularly interested in the eigenvalues oil the unit circle, which are difficult to estimate. The convergence and backward error of the algorithm are analyzed and three numerical examples are presented. Our experience shows that Our algorithm is efficient in comparison to the few existing approaches for small to medium size problems. (C) 2009 Elsevier B.V. All rights reserved.
Canine CD8 T cells showing NK cytotoxic activity express mRNAs for NK cell-associated surface molecules
(2010-02-15)
Lin, Yi-Chun
;
Huang, Yi-Chun
;
Wang, Yu-Shan
;
Juang, Rong-Huay
;
Liao, Kuang-Wen
Natural killer (NK) cells have been considered to be a group of lymphocytes lacking clonally distributed receptors for antigens typical of T cells and B cells. in some mammalian species, including humans, a subpopulation of CD8(+) peripheral blood lymphocytes (PBLs) exhibits NK activity. This NK subpopulation has not been well characterized in mammals and its characterization is particularly poor in the dog. In this study, we demonstrated that a subset of canine CD8(+) cells derived from PBLs and lymphokine (IL-2)-activated killers (LAKs) of PBLs that was CD3(+), CD4(-), CD21(-), CD5(lo), alpha/beta TCR(+), and gamma/delta TCR(-) contained substantially higher levels of mRNAs for NK cell-related receptors (NKp30, NKp44, NKG2D, 2B4, and CD16 for PBL, and NKG2D and CD56 for LAK) than the corresponding CD8(-) cells. This subset of CD8(+) lymphocytes derived from LAKs also displayed significantly higher NK cytotoxic activity than the corresponding CD8(+) cells. In contrast, CD8(+) cells derived from nonstimulated PBLs showed very low levels of NK cytotoxic activity. Our results indicate that, in IL-2-stimulated PBLs, canine CD8(+) cells are an important subset associated with NK cytotoxic activity. (C) 2009 Elsevier B.V. All rights reserved.
Efficiency Improvement of GaN-Based Light-Emitting Diode Prepared on GaN Nanorod Template
(2010-02-15)
Kuo, C. H.
;
Chang, L. C.
;
Kuo, C. W.
;
Chi, G. C.
;
光電工程學系
We demonstrated the formation of GaN-based nanorod (NR) structure by using self-assemble Ni nanoislands as the etching mask. It was found that crystal quality of the GaN epilayer prepared on an NR GaN template was significantly better than that prepared with a conventional low-temperature GaN nucleation layer. With the NR GaN template, it was found that 20-mA light-emitting diode (LED) output power can be enhanced by 39.8%, as compared to the conventional LED.
Insight into the performance enhancement of double-gated polycrystalline silicon thin-film transistors with ultrathin channel
(2010-02-15)
Lin, Zer-Ming
;
Lin, Horng-Chih
;
Chen, Wei-Chen
;
Huang, Tiao-Yuan
;
電子工程學系及電子研究所
In this letter, characteristics of independently-controllable double-gated polycrystalline silicon (poly-Si) thin-film transistors (TFTs) with ultrathin channel are characterized and analyzed experimentally and theoretically. As compared with the single-gated mode where only one of the gates is used for driving the device, 1.3-2.1 fold increase in drive current is achieved under double-gated mode as the two gates are biased simultaneously for driving the device. A remarkable lowering of barrier height 7-12 meV in the latter case due to the coupling of the two gate biases is identified as the major origin for such performance enhancement.
Wavelength-Tunable InGaAs-Capped Quantum-Dot Infrared Photodetectors
(2010-02-15)
Lin, Wei-Hsun
;
Tseng, Chi-Che
;
Chao, Kuang-Ping
;
Mai, Shu-Cheng
;
Lin, Shih-Yen
Quantum-dot infrared photodetectors (QDIPs) with InGaAs capping layers are investigated. Compared with the standard QDIP with 2.5-mono-layer (ML) InAs QDs, the detection wavelength is shifted from 6 to 7.9 m for an 8-nm InGaAs-capped QDIP. By decreasing the QD coverage from 2.5 to 2.0 ML, an even longer detection wavelength 10.4 m is observed, which is attributed to the higher energy levels of the QD excited states resulted from the smaller QDs. By further increasing the capping layer thickness to 12 nm, longer detection wavelengths with broad response 10-18 m is observed for the InGaAs-capped QDIP.
Glass transition temperature enhancement of PMMA through copolymerization with PMAAM and PTCM mediated by hydrogen bonding
(2010-02-15)
Lin, Chien-Ting
;
Kuo, Shiao-Wei
;
Huang, Chih-Feng
;
Chang, Feng-Chih
;
應用化學系
A series of poly(methyl methacrylate-co-methacrylamide-co-tricyclodecyl methacrylate) (PMMA-co-PMAAM-co-PTCM) copolymers possessing high glass transition temperatures and high transparency are prepared. By incorporating the aliphatic tricyclodecyl methacrylate moiety into the PMMA-co-PMAA main chain results in high glass transition temperature and high transparency of PMMA-based polymeric material. The TCM content affects the fraction of hydrogen bonding in these terpolymers, small content of TCM does not sacrifice the fraction of hydrogen-bonded association in and does not cause T(g) decrease. The extent of free amide group plays the major role in dictating moisture absorption of terpolymers. The incorporation of TCM significantly reduces the moisture absorption of terpolymers due to its hydrophobic and bulky tricyclodecyl group. In addition, the TCM plays the role of inert diluent to convert portion of the strong self-associated hydrogen bonded amide groups into inter-associated hydrogen bonding between carbonyl groups of ester units and MAAM. (C) 2010 Elsevier Ltd. All rights reserved.
Polymeric Dopant Effects of Bent-Core Covalent-Bonded and Hydrogen-Bonded Structures on Banana-Shaped Liquid Crystalline Complexes
(2010-02-15)
Yang, Po-Jen
;
Wang, Ling-Yung
;
Tang, Chieh-Yin
;
Lin, Hong-Cheu
;
材料科學與工程學系
Two series of banana-shaped liquid crystalline (LC) H-bonded complexes HP(m)/CB(n) (i.e., bent-core H-bonded side-chain homopolymer HP mixed with bent-core covalent-bonded small molecule CB) and CP(m)/HB(n) (i.e., bent-core covalent-bonded side-chain homopolymer CP mixed with bent-core H-bonded small molecular complex HB) with various m/n molar ratios were developed. The bent-core covalent- and H-bonded structural moieties were homopolymerized in the banana-shaped LC H-bonded complexes HP(m)/CB(n) and CP(m)/HB(n), respectively. The influences of m/n molar ratios (polymeric moieties vs. small molecular moieties) on the mesomorphic and electro-optical properties of both banana-shaped LC H-bonded complexes HP(m)/CB(n) and CP(m)/HB(n) were investigated. The polar smectic phases could be achieved and stabilized by smaller contents of polymeric dopants in banana-shaped LC H-bonded complexes, such as HP1/CB10, HP1/CB15, CP1/HB10, and CP1/HB15, which possessed tunable spontaneous polarization (Ps) values according to the molar ratios of m/n, that is, lower Ps values obtained in H-bonded complexes HP(m)/CB(n), and CP(m)/HB(n) with higher ratios of H-bonded moieties (larger m/n molar ratios), respectively. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 764-774, 2010
Temperature-Dependent Electroluminescence Efficiency in Blue InGaN-GaN Light-Emitting Diodes With Different Well Widths
(2010-02-15)
Wang, C. H.
;
Chen, J. R.
;
Chiu, C. H.
;
Kuo, H. C.
;
Li, Y. -L.
Temperature dependence of electroluminescence (EL) efficiency in blue InGaN-GaN multiple-quantum-well (MQW) light-emitting diodes (LEDs) with different well widths is systematically investigated. The EL efficiency at 300 K shows a maximum at the input current of 4, 10, and 60 mA for the LEDs with 1.5-, 2.0-, and 2.5-nm QWs, respectively. Nevertheless, the droop behavior at 80 K is mainly dominated by the low hole mobility and near independence on the QW thickness. According to the simulation results, it is found that the distinct efficiency droop behavior for the LEDs with different well widths at high and low temperature is strongly dependent on the effects of electron overflow and nonuniform hole distribution within the MQW region.
Lasing characteristics at different band edges in GaN photonic crystal surface emitting lasers
(2010-02-15)
Chen, S. W.
;
Lu, T. C.
;
Hou, Y. J.
;
Liu, T. C.
;
Kuo, H. C.
We have investigated the lasing characteristics of GaN-based two-dimensional photonic crystal surface emitting lasers (PCSELs) with different PC lattice constants by using angled resolved spectroscopy. Due to the Bragg diffraction theory, normalized frequency of lasing wavelength of PCSELs can be exactly matched with three distinct band-edge frequencies (Gamma 1, K2, and M3) in the photonic band diagram. The three band-edge frequencies (Gamma 1, K2, and M3) have different emission angles corresponding to the normal direction of the sample (0 degrees, 29 degrees, and 59.5 degrees).
文章產生系統及方法
(2010-02-16)
李嘉晃
;
余思翰
;
陳智維
本發明提供一種文章產生系統。該文章產生系統包含綜合語料庫、特定主題語料庫、判斷模組、決定模組、選取模組及組合模組。當特定主題被決定時，判斷模組根據綜合語料庫與特定主題語料庫產生對應於特定主題之複數個主題關鍵詞。決定模組根據複數個主題關鍵詞從特定主題語料庫中決定複數個填充字串。選取模組自複數個主題關鍵詞中選出複數個目標關鍵詞，並根據複數個目標關鍵詞從複數個填充字串中選出複數個候選填充字串。組合模組根據複數個目標關鍵詞與複數個候選填充字串形成與特定主題相關之文章。