Browsing by Issue Date, starting with "2016-08-02"

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Effect of Peptide Sequences on Supramolecular Interactions of Naphthaleneimide/Tripeptide Conjugates
(2016-08-02)
Yeh, Mei-Yu
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Huang, Ching-Ting
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Lai, Tsung-Sheng
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Chen, Fang-Yi
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Chu, Nien-Tzu
In this study, we reported a significant difference in the supramolecular hydrogelation of newly discovered NI-GFF (NI-Gly-L-Phe-L-Phe) and NI-FFG (NI-L-Phe-L-Phe-Gly) on the basis of their phase diagrams. With a small difference in the peptide chain between NI-GFF and NI-FFG, we observed a significant difference in their self-assembly properties; NI-GFF formed a stable gel at neutral pH, whereas NI-FFG did not, under the same conditions. From spectroscopic and computational studies, intermolecular pi-pi interactions and extended hydrogen bonding interactions might reinforce the intermolecular interactions of NI-GFF, which may facilitate the formation of the self-assembled nanostructures and the hydrogel. In addition, the aggregation-induced emission (AIE)-active NI-GFF reveals relatively good biocompatibility compared with that of NI-FFG for two commonly used cell lines, suggesting that it is a promising candidate for use as a supramolecular material in biomedical applications. Our results highlight the importance of tripeptide sequences in a self-assembling hydrogel system.
Long noncoding RNA TUG1 is downregulated in non-small cell lung cancer and can regulate CELF1 on binding to PRC2
(2016-08-02)
Lin, Pei-Chin
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Huang, Hsien-Da
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Chang, Chun-Chi
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Chang, Ya-Sian
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Yen, Ju-Chen
Background: Long noncoding RNAs (lncRNAs) play crucial roles in tumorigenesis, and lncRNA taurine-upregulated gene 1 (TUG1) has been proven to be associated with several human cancers. However, the mechanisms of TUG1-involved regulation remain largely unknown. Methods: We examined the expressions of TUG1 in a cohort of 89 patients with non-small cell lung cancer (NSCLC) to determine the association between TUG1 expression and clinical parameters. We used circular chromosome conformation capture (4C) coupled with next-generation sequencing to explore the genome regions that interact with TUG1 and the TUG1-mediated regulation. Results: TUG1 was significantly downregulated, and the TUG1 downregulation correlated with sex (p = 0.006), smoking status (p = 0.016), and tumor differentiation grade (p = 0.001). Knockdown of TUG1 significantly promoted the proliferation of NSCLC cells. According to the bioinformatic analysis result of TUG1 4C sequencing data, 83 candidate genes and their interaction regions were identified. Among these candidate genes, CUGBP and Elav-like family member 1 (CELF1) are potential targets of TUG1 in-trans regulation. To confirm the interaction between TUG1 and CELF1, relative expressions of CELF1 were examined in TUG1 knockdown H520 cells; results showed that CELF1 was significantly upregulated in TUG1 knockdown H520 cells. RNA immunoprecipitation was then performed to examine whether TUG1 RNA was bound to PRC2, a TUG1-involved regulation mechanism reported in previous studies. The results demonstrated that TUG1 RNA was bound to enhancer of zeste protein 2/embryonic ectoderm development (EZH2/EED), which is essential for PRC2. Finally, our designed ChIP assay revealed that the EZH2/EED was bound to the promotor region of CELF1 within 992 bp upstream of the transcript start site. Conclusion: TUG1 is downregulated in NSCLC. Using TUG1 4C sequencing and bioinformatic analysis, we found CELF1 to be a potential target of TUG1 RNA in in-trans regulation. Moreover, subsequent experiments showed that TUG1 RNA could bind to PRC2 in the promotor region of CELF1 and negatively regulate CELF1 expressions in H520 cells. Our results may facilitate developing new treatment modalities targeting TUG1/PRC2/CELF1 interactions in patients with NSCLC.
An unprecedented oxidative intermolecular homo coupling reaction between two sp(3)C-sp(3)C centers under metal-free condition
(2016-08-03)
Sahoo, Santosh K.
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應用化學系
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Department of Applied Chemistry
An unprecedented formation of benzylic sp(3)C-sp(3)C coupled dibenzylic products has been illustrated. The reactions have been carried out in the presence of three oxidizing reagents, i.e., diacetoxy-iodobenzene (IBDA), N-fluorobenzenesulfonimide (NFSI), and pyridine (Py) using toluene derivatives. (C) 2016 Elsevier Ltd. All rights reserved.
New Material Transistor with Record-High Field-Effect Mobility among Wide-Band-Gap Semiconductors
(2016-08-03)
Shih, Cheng Wei
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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
At an ultrathin 5 nm, we report a new high-mobility tin oxide (SnO2) metal-oxide-semiconductor field-effect transistor (MOSFET) exhibiting extremely high field-effect mobility values of 279 and 255 cm(2)/V-s at 145 and 205 degrees C, respectively. These values are the highest reported mobility values among all wide-band-gap semiconductors of GaN, SiC, and metal-oxide MOSFETs, and they also exceed those of silicon devices at the aforementioned elevated temperatures. For the first time among existing semiconductor transistors, a new device physical phenomenon of a higher mobility value was measured at 45-205 degrees C than at 25 degrees C, which is due to the lower optical phonon scattering by the large SnO2 phonon energy. Moreover, the high on-current/off-current of 4 x 10(6) and the positive threshold voltage of 0.14 V at 25 degrees C are significantly better than those of a graphene transistor. This wide-band-gap SnO2 MOSFET exhibits high mobility in a 25-205 degrees C temperature range, a wide operating voltage of 1.5-20 V, and the ability to form on an amorphous substrate, rendering it an ideal candidate for multifunctional low-power integrated circuit (IC), display, and brain-mimicking three-dimensional IC applications.
Fractal frequency spectrum in laser resonators and three-dimensional geometric topology of optical coherent waves
(2016-08-03)
Tung, J. C.
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Tuan, P. H.
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Liang, H. C.
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Huang, K. F.
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Chen, Y. F.
We theoretically verify that the symmetry breaking in spherical resonators can result in a fractal frequency spectrum that is full of numerous newaccidental degeneracies to cluster around the unperturbed degenerate cavity. We further experimentally discover that the fractal frequency spectrum excellently reflects the intimate connection between the emission power and the degenerate mode numbers. It is observed that the wave distributions of lasing modes at the accidental degeneracies are strongly concentrated on three-dimensional (3D) geometric topology. Considering the overlapping effect, the wave representation of the coherent states is analytically derived to manifest the observed 3D geometric surfaces.
Rhodium-Catalyzed Regioselective Synthesis of Isocoumarins through Benzothiadiazine-Fused Frameworks
(2016-08-05)
Dalvi, Prashant B.
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Lin, Kuang-Ling
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Kulkarni, Manohar V.
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Sun, Chung-Ming
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應用化學系
An unprecedented two-step, one-pot synthesis of benzimidazothiadiazine 5,5-dioxides is presented. Reaction condition based regioselectivity has been achieved where fused benzimidazo[1,2-b][1,2,4]thiadiazines are exclusively formed under thermal conditions, whereas benzimidazo[2,1-c][1,2,4]thiadiazines were created only under microwave irradiation. The salient features of this protocol include a regioselective sulfonylation of 2-aminobenzimidazole with o-halo sulfonyl chlorides followed by N-C bond formation. The acid forms of these fused regioisomers have been used to introduce novel guanidine containing isocoumarin frameworks.
交大e-News第214期-交大台大首創兩校合聘教師制度
(2016-08-05)
國立交通大學秘書室
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Secretariat
A novel double pipe pulsating heat pipe design to tackle inverted heat source arrangement
(2016-08-05)
Tseng, Chih-Yung
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Yang, Kai-Shing
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Chien, Kuo-Hsiang
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Wu, Shih-Kuo
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Wang, Chi-Chuan
Traditional pulsating heat pipe with fewer turns is functional only when the heat source is placed at the bottom while the heat sink is on top. This study proposes a novel design having alternative double-pipe tube diameter with some extra open connections of these double-pipes. By introducing extra un-balanced pressure force, capillary force and gravity force, the PHP can be easily starting up even for an opposite heat source/sink arrangement while the conventional single tube design fails to start up with this opposite arrangement. The thermal resistance of double pipe PHP can be lowered to 0.0729 W/K with an effective thermal conductivity of 12,603 W/m.K when the heat source is placed on top. Yet the thermal resistance for the proposed double pipe design is only half of the single tube design. (C) 2016 Elsevier Ltd. All rights reserved.
Surface plasmon optical antennae in the infrared region with high resonant efficiency and frequency selectivity
(2016-08-08)
Ueno, Kosei
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Sun, Quan
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Mino, Masahiro
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Itoh, Takumi
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Oshikiri, Tomoya
Infrared light has received attention for sensor applications, including fingerprint spectroscopy, in the bioengineering and security fields. Surface plasmon physics enables the operation of a light harvesting optical antenna. Gold nanochains exhibit localized surface plasmon resonance (LSPR) in the infrared region with high frequency selectivity. However, a feasible design for optical antennae with a higher resonant efficiency and frequency selectivity as a function of structural design and periodicity is still unknown. In the present study, we investigated the relationship between the resonant efficiency and frequency selectivity as a function of the structural design of gold nanochains and explored structural periodicity for obtaining highly frequency-selective optical antennae. An optical antenna design with higher resonant efficiency is proposed on the basis of its efficient interaction with non-polarized light. (C) 2016 Optical Society of America
Broadband gold nanoantennas arrays with transverse dimension effects
(2016-08-08)
Su, Chen-Wei
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Chen, Kuo-Ping
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光電系統研究所
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影像與生醫光電研究所
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Institute of Photonic System
Broadband resonance in gold paired-rods nanoantennas and paired-strips gratings is investigated when the nanostructure's transverse (non-polarization) dimension is changed from paired-rods to paired-strips. Increasing the transverse dimension blue shifts the resonance wavelength and widens its bandwidth due to cancellation of the magnetic field between nanoantennas. A derived resistor-inductor-capacitor (RLC) equivalent circuit model verifies the nanostructures' resonance when elongating the transverse dimensions. Paired-strips gratings have a bandwidth 2.04 times that of paired-rods nanoantennas. (C) 2016 Optical Society of America
Novel Water-Soluble Cyclodextrin-Based Conjugated Polymer for Selective Host-Guest Interactions of Cationic Surfactant CTAB and Reverse FRET with Rhodamine B Tagged Adamantyl Guest
(2016-08-09)
Dwivedi, Atul Kumar
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Singh, Ravinder
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Singh, Ashutosh
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Wei, Kung-Hwa
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Wu, Chu-Ya
A new water-soluble pi-conjugated main-chain polymer P1 bearing a beta-cyclodextrin (beta-CD) pendant was designed and synthesized. The aggregation and disaggregation of P1 generated faded yellow-greenish and bright-yellow emissions, respectively. The inclusion complexation capability of P1 through beta-CD pendant with a cationic surfactant cetyltrimethylammonium bromide (CTAB) guest and associative interactions of P1 with Fe3+ through triazole spacers resulted in significantly enhanced and completely diminished emission profiles of P1 in pure water, respectively. Interestingly, ADRhB as another rhodamine B (RhB) tagged adamantyl guest was transformed into ADRhB(0), i.e., the open form of ADRhB, to generate RhB emission in the presence of Fe3+ ion selectively for the pendent host beta-CD of PI, and the further interaction of.ADRhB(0)/Fe3+ with P1 prevailed a completely quenched RhB emission via the inclusion complexation of adamantyl terminal of ADRhB (0) in beta-CD. Moreover, stronger interactions of CTAB with beta-CD further generated RhB emission of ADRhB(0) even in the presence of acceptor Pl. Finally, a novel beta-CD bearing water-soluble P1 with selective and strong interactions of CTAB toward disaggregation events in pure water, and further electrostatic repulsion and utilization of RhB via RhB-tagged adamantyl guest ADRhB(0) as a donor revealed the reverse fluorescence resonance energy transfer (FRET) process of P1.
Functional Supramolecular Polypeptides Involving pi-pi Stacking and Strong Hydrogen-Bonding Interactions: A Conformation Study toward Carbon Nanotubes (CNTs) Dispersion
(2016-08-09)
Huang, Cheng-Wei
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Mohamed, Mohamed Gamal
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Zhu, Chao-Yuan
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Kuo, Shiao-Wei
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應用化學系
New supramolecular polypeptides have been prepared through simple ring-opening polymerization and "click" reactions. Postfunctionalization with diaminopyridine (DAP) moieties, capable of multiple hydrogen bonding, was an efficient approach toward forming a-helical-dominant polypeptides. The physically cross-linked networks produced upon self-organization of the DAP units increased the glass transition temperature (T-g) of the polymers and sustained the secondary structures of the polypeptides. Additional thermal responsivity resulted from dynamic noncovalent bonding on the polymer side chains. Molecular recognition through heterocomplementary DAP thymine (T) base pairs was revealed spectroscopically and then used to construct poly(y-propargylL-glutamate)-g-N-(6-acetamidopyridin-2-y1)-11-undecanamide/thyminylpyrene (PPLG-DAP/Py-T) supramolecular complexes. Transmission electron microscopy images revealed that this complex was an efficient dispersant of carbon nanotubes (CNTs). Indeed, it could disperse CNTs in both polar and nonpolar media, the direct result of combining two modes of secondary noncovalent bonding: multiple hydrogen bonding and pi-pi interactions. Furthermore, CNT composites fabricated with biocompatible polymers and high value of T-g should enable the development of bio-inspired carbon nanostructures and lead the way toward their biomedical applications.
Packing Principles for Donor-Acceptor Oligomers from Analysis of Single Crystals
(2016-08-09)
Huang, Chi-Feng
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Wu, San-Lien
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Huang, Yi-Fan
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Chen, Ying-Chen
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Chang, Shu-Ting
D-A conjugated molecules are complicated in both their molecular and their packing structures. In this perspective, we summarize more than 40 crystal lattices of conjugated oligomers to identify the morphological influence of each building block on the D-A molecules. These lattice structures reveal not only the packing preferences of the conjugated oligomers but also the conformational disorder in the lattices. The presence of this disorder in slowly grown crystals implies that attaining total long-range conformational order is challenging for D-A oligomers, which are structurally complicated and readily distorted and which have building blocks of incommensurate packing dimensions. In optoelectronic applications, a decreased duration of processing can prevent ordering and trap the thin films of D-A oligomers from becoming crystalline phases. Although D-A oligomers conform to packing principles in the formation of a single crystal, their phase behaviors in the formation of active thin films are much more difficult to comprehend. Continuous advances in methods of characterization are still strongly required for the steps of attaining a true structure property relation of D-A oligomers in active films for optoelectronic applications.
Anti-Hyperglycemic Agents and New-Onset Acute Myocardial Infarction in Diabetic Patients with End-Stage Renal Disease Undergoing Dialysis
(2016-08-11)
Lin, Ting-Tse
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Wu, Chih-Chen
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Yang, Yao-Hsu
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Lin, Lian-Yu
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Lin, Jiunn-Lee
Background Diabetes and chronic kidney disease (CKD) are a high-stakes combination for cardiovascular disease. Patients with decreased kidney function and end-stage renal disease ( ESRD) have increased risk of hypoglycemia when attaining better glycemic control, leading to higher risk of myocardial infarction (MI). For these patients, which kinds of anti-hyperglycemic agents would be associated with higher risk of MI is not clear. Methods We identified patients from a nation-wide database called Registry for Catastrophic Illness, which encompassed almost 100% of the patients receiving dialysis therapy in Taiwan from 1995 to 2008. Patients with diabetes and ESRD were selected as the study cohort. Propensity score adjustment and Cox's proportional hazards regression model were used to estimate the hazard ratios (HRs) for new-onset MI. Results Among 15,161 patients, 39% received insulin, 40% received sulfonylureas, 18% received meglitinides and 3% received thiazolidinedione (TZD). After a median follow-up of 1,357 days, the incidence of MI was significant increase in patients taking sulfonylureas (HR =1.523, 95% confidence interval [CI]=1.331-1.744), meglitinides ( HR=1.251, 95% CI=1.048-1.494) and TZD (HR=1.515, 95% CI=1.071-2.145) by using patients receiving insulin therapy as the reference group. The risk of MI remains higher in other three groups in subgroup analyses. Conclusions In conclusion, among diabetic patients with ESRD undergoing dialysis, the use of sulfonylureas, meglitinides and TZD are associated with higher risk of new-onset MI as compared with insulin.
Determination of the total absorption peak in an electromagnetic calorimeter
(2016-08-11)
Cheng, Jia-Hua
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Wang, Zhe
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Lebanowski, Logan
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Lin, Guey-Lin
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Chen, Shaomin
A physically motivated function was developed to accurately determine the total absorption peak in an electromagnetic calorimeter and to overcome biases present in many commonly used methods. The function is the convolution of a detector resolution function with the sum of a delta function, which represents the complete absorption of energy, and a tail function, which describes the partial absorption of energy and depends on the detector materials and structures. Its performance was tested with the simulation of three typical cases. The accuracy of the extracted peak value, resolution, and peak area was improved by an order of magnitude on average, relative to the Crystal Ball function. (C) 2016 Elsevier B.V. All rights reserved.
Photoinduced diffusion molecular transport
(2016-08-14)
Rozenbaum, Viktor M.
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Dekhtyar, Marina L.
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Lin, Sheng Hsien
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Trakhtenberg, Leonid I.
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應用化學系
We consider a Brownian photomotor, namely, the directed motion of a nanoparticle in an asymmetric periodic potential under the action of periodic rectangular resonant laser pulses which cause charge redistribution in the particle. Based on the kinetics for the photoinduced electron redistribution between two or three energy levels of the particle, the time dependence of its potential energy is derived and the average directed velocity is calculated in the high-temperature approximation (when the spatial amplitude of potential energy fluctuations is small relative to the thermal energy). The thus developed theory of photoinduced molecular transport appears applicable not only to conventional dichotomous Brownian motors (with only two possible potential profiles) but also to a much wider variety of molecular nanomachines. The distinction between the realistic time dependence of the potential energy and that for a dichotomous process (a step function) is represented in terms of relaxation times (they can differ on the time intervals of the dichotomous process). As shown, a Brownian photomotor has the maximum average directed velocity at (i) large laser pulse intensities (resulting in short relaxation times on laser-on intervals) and (ii) excited state lifetimes long enough to permit efficient photoexcitation but still much shorter than laser-off intervals. A Brownian photomotor with optimized parameters is exemplified by a cylindrically shaped semiconductor nanocluster which moves directly along a polar substrate due to periodically photoinduced dipole moment (caused by the repetitive excited electron transitions to a non-resonant level of the nanocylinder surface impurity). Published by AIP Publishing.
A crossover adjustment for improving sea surface height mapping from in-situ high rate ship-borne GNSS data using PPP technique
(2016-08-15)
Guo, Jinyun
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Dong, Zhenghua
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Tan, Zhengguang
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Liu, Xin
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Chen, Chuanfa
Ship-borne global navigation satellite system (GNSS) technique can overcome the weakness of satellite altimetry and tide gauge in measuring sea surface heights (SSHs) over coastal seas. Ship-borne GNSS technique can be used to calibrate SSHs determined by the satellite altimetry and tide gauge. The ship borne GNSS data are processed with the single-epoch precise point positioning (PPP) method to estimate SSHs which are filtered by the Gaussian filter to weaken and/or remove effects of sea wind and wave field. Tidal corrections are also taken into consideration to improve SSHs. One crossover adjustment method is put forward to calculate the bias and drift along the ship route and assess the accuracy of SSHs. We processed the in-situ ship-borne GPS data over the offshore sea around Keelung to compute precisely SSHs with the single-epoch PPP. Statistical results of SSH differences of crossover points indicate that the root mean squares error of SSHs determined by the ship-borne GPS is up to level of 12.9 cm over the offshore sea similar to 30 km far away to land. (C) 2016 Elsevier Ltd. All rights reserved.
用於製備氫氣之觸媒及其製法
(2016-08-16)
李積琛
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蔡品雯
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謝和諶
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陳昀聲
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張原嘉
一種用於製備氫氣之觸媒及其製法，該製法係包括於包含界面活性劑之第一有機溶劑中加入第一金屬源、第二金屬源、第三金屬源及鈰源，以形成膠體混合物，其中，該第一金屬源之金屬係IIIB族金屬，該第二金屬源之金屬係選自鹼金屬、鹼土金屬及IIIB族金屬所組成群組之其中一者，該第三金屬源係過渡金屬；?燒該膠體混合物，以形成金屬固溶體；以及使載體承載該金屬固溶體，以得到該觸媒。將本發明所製備之觸媒用於乙醇氧化重組時，能使該乙醇氧化重組的反應溫度明顯下降，且該觸媒經長時間使用後，該乙醇氧化重組仍維持在高的乙醇轉換率及氫氣選擇率，顯示出該觸媒具有長時間使用的穩定性。
A study on the plating and wetting ability of ruthenium-tungsten multi-layers for advanced Cu metallization
(2016-08-16)
Kuo, Tai-Chen
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Su, Yin-Hsien
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Lee, Wen-Hsi
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Liao, Wei-Hsiang
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Wang, Yu-Sheng
In this study, the plating and wetting ability of Cu/Ruthenium-Tungsten (RuW)/silicon oxide (SiO2) multi-layer stacks were investigated. RuW alloy films were prepared on a SiO2 layer by sputtering, followed by a deposition of a Cu thin film by electro-plating. Scanning electron microscopy (SEM) top view images shows that Cu films can be electroplated on RuW, with smaller Cu nuclei size but in a more highly concentrated and uniform distribution than Cu films electroplated on Ta or TaN. The rate of Cu nucleation decreases and larger Cu clusters were formed on the RuW alloy films with increasing W content. Cu/RuW/SiO2 samples were annealed at 400 degrees C for 30 min and then characterized using SEM. There were fewer pin holes on the surface of a pure Cu/Ru stack compared to Cu/RuW multilayers. Cu/RuW/SiO2 multi -layers had fewer pin holes than Cu/Ta/SiO2 structures processed under similar conditions. The wetting angle, measured by SEM, of Cu on a RuW substrate (43) was still lower than that of Cu on a Ta substrate (123 degrees), which suggests that the adhesion strength of Cu onto RuW alloy is better than that onto Ta. Preliminary studies of Cu diffusion through 25 nm RuW layers at 650 degrees C showed no Cu penetration into the underlying Si in a Cu/RuW/Si multi-layer test structure. (C) 2016 Elsevier B.V. All rights reserved.
Scalable Patterning of MoS2 Nanoribbons by Micromolding in Capillaries
(2016-08-17)
Hung, Yu-Han
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Lu, Ang-Yu
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Chang, Yung-Huang
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Huang, Jing-Kai
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Chang, Jeng-Kuei
In this study, we report a facile approach to prepare dense arrays of MoS2 nanoribbons by combining procedures. of micromolding in capillaries (MIMIC) and thermolysis of thiosalts ((NH4)(2)MoS4) as the printing ink. The obtained MoS2 nanoribbons had a "thickness reaching as. low as 3.9 nm, a width ranging from 157 to 465 nm, and a length up to 2 cm. MoS2 nanoribbons with an extremely high aspect ratio (lengthiwidtfi) of similar to 7.4 X 10(8) were achieved. The MoS2 pattern can be printed on versatile substrates, such as SiO2/Si, sapphire, Au film, FTO/glass, and graphene-coated glass. The degree of crystallinity of the as-prepared MoS2 was discovered to be adjustable by varying the temperature through postannealing. The high-temperature thermolysis (1000 degrees C) results in high-quality conductive samples, and field-effect transistors, based on the patterned MoS2 nanoribbons were demonstrated and characterized, where the carrier mobility was comparable to that of thin-film MoS2. In contrast, the low-temperature-treated samples (170 degrees C) result in a unique nanocrystalline MOSx structure (x approximate to 2.5), where the abundant and exposed edge sites were obtained from highly dense arrays of nanoribbon structures by this MIMIC patterning method,: The patterned MoSx was revealed to have superior electrocatalytic efficiency (an overpotential of similar to 211 mV at 10 mA/cm(2) and a Tafel slope of 43 mV/dec) in the hydrogen evolution reaction (HER) when compared to the thin-film MoS2. The report introduces a new concept for rapidly fabricating cost-effective and high-density MoS2/MoSx natiostructures on versatile substrates, which may pave the way for potential applications in nanoelectronics/optoelectronics and frontier energy materials.