Browsing by Issue Date, starting with "2020-06-24"

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The Dust-to-Gas Ratio, Size Distribution, and Dust Fall-Back Fraction of Comet 67P/Churyumov-Gerasimenko: Inferences From Linking the Optical and Dynamical Properties of the Inner Comae
(2020-06-24)
Marschall, Raphael
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Markkanen, Johannes
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Gerig, Selina-Barbara
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Pinzon-Rodriguez, Olga
;
Thomas, Nicolas
In this work, we present results that simultaneously constrain the dust size distribution, dust-to-gas ratio, fraction of dust re-deposition, and total mass production rates for comet 67P/Churyumov-Gerasimenko. We use a 3D Direct Simulation Monte Carlo (DSMC) gas dynamics code to simulate the inner gas coma of the comet for the duration of the Rosetta mission. The gas model is constrained by ROSINA/COPS data. Further, we simulate for different epochs the inner dust coma using a 3D dust dynamics code including gas drag and the nucleus' gravity. Using advanced dust scattering properties these results are used to produce synthetic images that can be compared to the OSIRIS data set. These simulations allow us to constrain the properties of the dust coma and the total gas and dust production rates. We determined a total volatile mass loss of (6.1 +/- 1.5) center dot 10(9)kg during the 2015 apparition. Further, we found that power-laws withq=3.7-0.078+0.57are consistent with the data. This results in a total of5.1-4.9+6.0 center dot 109kg of dust being ejected from the nucleus surface, of which4.4-4.2+4.9 center dot 109kg escape to space and6.8-6.8+11 center dot 108kg (or an equivalent of14-14+22cm over the smooth regions) is re-deposited on the surface. This leads to a dust-to-gas ratio of0.73-0.70+1.3for the escaping material and0.84-0.81+1.6for the ejected material. We have further found that the smallest dust size must be strictly smaller than similar to 30 mu m and nominally even smaller than similar to 12 mu m.
Facet-Specific Photocatalytic Activity Enhancement of Cu2O Polyhedra Functionalized with 4-Ethynylanaline Resulting from Band Structure Tuning
(2020-06-24)
Chen, Tzu-Ning
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Kao, Jui-Cheng
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Zhong, Xin-Yan
;
Chan, Shang-Ju
;
Patra, Anindya S.
Cu2O rhombic dodecahedra, octahedra, and cubes were densely modified with conjugated 4-ethynylaniline (4-EA) for facet-dependent photocatalytic activity examination. Infrared spectroscopy affirms bonding of the acetylenic group of 4-EA onto the surface copper atoms. The photocatalytically inactive Cu2O cubes showed surprisingly high activity toward methyl orange photodegradation after 4-EA modification, while the already active Cu2O rhombic dodecahedra and octahedra exhibited a photocatalytic activity enhancement. Electron, hole, and radical scavenger experiments prove that the photocatalytic charge transport processes have occurred in the functionalized Cu2O cubes. Electrochemical impedance spectroscopy also indicates reduced charge transfer resistance of the functionalized Cu2O crystals. A band diagram constructed from UV-vis spectral and Mott-Schottky measurements reveals significant band energy shifts in all Cu2O samples after decorating with 4-EA. From density functional theory (DFT) calculations, a new band has emerged slightly above the valence band maximum within the band gap of Cu2O, which has been found to originate from 4-EA through band-decomposed charge density analysis. The increased charge density localized on the 4-EA molecule and the smallest electron transition energy to reach the 4-EA-generated band are factors making {100}-bound Cu2O cubes photocatalytically active. Proper molecular decoration represents a powerful approach to improving the photocatalytic efficiency of semiconductors.
Lasing Properties Activation by Constitutional Isomerism of an Electron-Accepting Group
(2020-06-25)
Szukalski, Adam
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Haupa, Karolina A.
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Janczak, Jan
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Przybyl, Bartosz
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Sznitko, Lech
Materials engineering plays a pivotal role considering its manifold applications, i.e., in medicine as individualized drug carriers or in advanced technologies such as optoelectronic devices and others. Recently, increasing interest in the pyrazoline derivatives family of compounds was noticed. In this paper, we report on the constitutional isomerism influence on photophysical properties of low molecular, push-pull type of pyrazole-based organic chromophores. Particularly, we show the ability of optical properties tailoring by changing the substitution of phenyl ring extended by effective electron-accepting moiety in ortho and para positions. Such a structural change in molecule results in a shift of photoluminescence spectra as well as the activation or deactivation of gain mechanism for multimode laser emission. In order to confirm ground state molecular structures for both isomers we performed time-dependent DFT calculations in a solvent environment. In addition, structural analysis of spontaneously grown single crystals was carried out using X-ray spectroscopy. The above-mentioned studies allowed us to define the isomer's molecular geometries and charge distribution in excited and ground states and to distinguish the significant differences in crystallographic structures. Combined experimental and theoretical research have resulted in a hypothesis of the molecular mechanism standing behind observed differences in optical properties of both isomers. Importantly, such an approach can be useful for materials engineering, allowing us to predict the features of novel materials for optoelectronics and photonics.
Linear, mixed-valent homocatenated tri-tin complexes featuring Sn-Sn bonds
(2020-06-25)
Chang, Wei-Chieh
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Raj, Ankit
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Hiramatsu, Hirotsugu
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Li, Han-Jung
;
Ziegler, Micah S.
A series of tri-tin complexes((LSn)-Sn-Ph)(3)Xwith triple-decker structures (L-Ph= 2,5-di(o-pyridyl)-3,4-diphenylpyrrolate; X = Cl, AlCl4, OTf, and PF6) was synthesized by reducingL(Ph)SnClwith (LiBBu3H)-Bu-s and subsequent reactions. Structural characterization of((LSn)-Sn-Ph)(3)Clrevealed a Sn-Sn-Sn core, and DFT calculations suggest that its HOMO is primarily sigma-bonding along the tri-tin framework.((LSn)-Sn-Ph)(3)Clreacts with W(CO)(5)THF to afford((LSn)-Sn-Ph)(2)(W(CO)(5))(2)andL(Ph)SnCl, implying that((LSn)-Sn-Ph)(3)Clmay exhibit dynamic behavior in solution.
CONY: A Bayesian procedure for detecting copy number variations from sequencing read depths
(2020-06-26)
Wei, Yu-Chung
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Huang, Guan-Hua
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統計學研究所
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Institute of Statistics
Copy number variations (CNVs) are genomic structural mutations consisting of abnormal numbers of fragment copies. Next-generation sequencing of read-depth signals mirrors these variants. Some tools used to predict CNVs by depth have been published, but most of these tools can be applied to only a specific data type due to modeling limitations. We develop a tool for copy number variation detection by a Bayesian procedure, i.e., CONY, that adopts a Bayesian hierarchical model and an efficient reversible-jump Markov chain Monte Carlo inference algorithm for whole genome sequencing of read-depth data. CONY can be applied not only to individual samples for estimating the absolute number of copies but also to case-control pairs for detecting patient-specific variations. We evaluate the performance of CONY and compare CONY with competing approaches through simulations and by using experimental data from the 1000 Genomes Project. CONY outperforms the other methods in terms of accuracy in both single-sample and paired-samples analyses. In addition, CONY performs well regardless of whether the data coverage is high or low. CONY is useful for detecting both absolute and relative CNVs from read-depth data sequences. The package is available at https://github.com/weiyuchung/CONY.
Graphene-Loaded Plasmonic Zirconium Nitride and Gold Nanogroove Arrays for Surface-Charge Modifications
(2020-06-26)
Yu, Min-Wen
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Ishii, Satoshi
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Ku, Ji-Ren
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Yang, Jhen-Hong
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Huang, Chih-Hsiang
Graphene-on-metal (G/M) heterostructures have gained considerable attention in recent years owing to their outstanding optical and electrical properties. In this study, the polarity of graphene doping to different metallic materials underneath graphene is analyzed for applications in surface-charge modifications. Kelvin probe force microscopy clearly reveals the charge-transfer effects of plasmonic zirconium nitride (ZrN) and gold (Au) on the formation of G/M heterostructures. In addition, both ZrN and Au nanogroove arrays are fabricated by focused ion beam to generate surface plasmon resonances. The charge-transfer effects influence the effective permittivities of ZrN and Au surfaces such that opposite plasmonic resonance shifts are demonstrated for the ZrN and Au nanogroove arrays. Our results show that the choice of metallic material is important for achieving a desired charge transfer in the loading of graphene onto metallic materials.
Highly hydrophobic metal-organic framework for self-protecting gate dielectrics
(2020-06-28)
Inamdar, Arif I.
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Pathak, Abhishek
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Usman, Muhammad
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Chiou, Kuan-Ru
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Tsai, Pei-Hsien
A hydrophobic metal-organic framework (MOF) showing high-kappa behaviour was synthesized by the reaction of copper ions with 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (HFDPA). The unique, highly hydrophobic nature of the material protects it from re-adsorbing water, even in a high humidity environment. The dielectric constant of the MOF showed an unprecedented increasing trend, reaching up to kappa approximate to 99 at 300 K and 1 kHz after the complete removal of guest and coordinated water molecules. The unusual dielectric behaviour of the compound along with its water resistant properties is the first report of such behaviour and it paves the way for the development of moisture-stable microelectronic devices.
2-Dimensional cross-shaped tetrathienonaphthalene-based ladder-type acceptor for high-efficiency organic solar cells
(2020-06-28)
Chang, Shao-Ling
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Cao, Fong-Yi
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Huang, Kuo-Hsiu
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Lee, Wei-Liang
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Lee, Meng-Hsun
AnNC-FICnonfullerene acceptor, using a didodecylnaphthodithiophene (NDT) embedded octacyclic ladder-type donorNC, had been described previously. In this work, a new cross-shapedTC-FICnonfullerene acceptor is designed by substitution of the NDT unit in theNCskeleton with a 2-dimensional didodecyltetrathienonaphthalene (TTN) unit. The 2-dimensionalTC pi-system with two vertically fused thiophenes strengthens the electron-donating ability, promotes pi-electron delocalization and enhances intramolecular donor-acceptor charge transfer and intermolecular pi-pi interactions. As a result,TC-FICshows more red-shifted and widened absorption compared to theNC-FICcounterpart. The PBDB-T:TC-FICdevice exhibits a higher efficiency of 11.6% which greatly outperformed the corresponding PBDB-T:NC-FICdevice with an efficiency of 7.52%. The dramatic 54% enhancement in efficiency is ascribed to the improved light-harvesting ability and enhanced charge mobilities which are benefited from the central 2-dimensionalTTNmoiety. By incorporatingPC(71)BMto improve absorption and electron transport, the ternary-blend PBDB-T : TC-FIC : PC(71)BMdevice (1 : 1 : 1 in wt%) achieves a highest PCE of 13.49% with an enhancedJ(sc)of 23.80 mA cm(-2), an FF of 64.4%, and aV(oc)of 0.88 V.
Probing Criegee intermediate reactions with methanol by FTMW spectroscopy
(2020-06-28)
Cabezas, Carlos
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Endo, Yasuki
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應用化學系
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Department of Applied Chemistry
Criegee intermediates (CIs) are carbonyl oxides generated from ozonolysis of unsaturated hydrocarbons in the atmosphere. The relatively long lifetime of CIs makes possible the bimolecular reactions with other atmospheric agents. These reactions can potentially be fast enough to contribute significantly to the tropospheric budgets of those species or to alter the rate of generation of secondary organic aerosols (SOAs). In particular, the new adducts formed in these reactions contribute SOA formation because they have larger molecular weights and lower vapor pressures than the reactants and are more condensable. alpha-alkoxyalkyl hydroperoxides are the nascent products derived from the insertion reactions of CIs with alcohols. In this work we report the direct detection of methoxymethyl hydroperoxide (HOOCH2OCH3, MMHP) and methoxyethyl hydroperoxide (HOOC(CH3)HOCH3, MEHP) as the reaction products between the CIs, CH2OO and CH3CHOO and methanol. High resolution Fourier transform microwave spectroscopy has been used to identify one and two conformers of MMHP and MEHP, respectively. The pre-reactive complex CH2OO-CH3OH was not observed in this experiment, which indicates that CH2OO shows a different reactivity toward methanol than that toward water. Our results for CH3CHOO + CH3OH show that MEHP is produced in similar ratios whensyn- andanti-CH3CHOO react with methanol vapor.
Highly Sensitive Lead Ion Detection in One Drop of Human Whole Blood Using Impedance-Modulated Field-Effect Transistors and a Portable Measurement Device
(2020-06-29)
Wang, Shin-Li
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Hsieh, Ching-Yen
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Sukesan, Revathi
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Chen, Jung-Chih
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Wang, Yu-Lin
This study reports the development of a rapid heavy metal ion screening tool for whole blood samples. The test system consists of an ion selective membrane-based impedance modulated field effect transistor (FET) sensor and a portable sensor measurement unit. This study focuses on the direct detection of lead ions in whole blood, without extensive sample pre-treatments. The sensing methodology is based on impedance changes in the membrane due to the specific ionophore-target metal ion interaction in the presence of a strong electric field. The changes in impedance caused by heavy metal ions are amplified by the FET to obtain a highly sensitive lead ion detection, with very low detection limit (near 10(-11) similar to 10(-10)M Pb2+). To reduce the complexity and enhance sensor performance, the whole blood samples are fractionated on chip without any external actuation/automation using simple gravitational blood cell separation. The test results in PBS, human serum and whole blood samples demonstrate high sensitivity and wide dynamic range of lead ion detection. The miniaturized extended gate FET sensor system is ideal for point of care and home-care diagnostics for heavy metal ion in blood.
Potential enhancement of host immunity and anti-tumor efficacy of nanoscale curcumin and resveratrol in colorectal cancers by modulated electro- hyperthermia
(2020-06-29)
Kuo, I-Ming
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Lee, Jih-Jong
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Wang, Yu-Shan
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Chiang, Hsin-Chien
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Huang, Cheng-Chung
BackgroundModulated electro-hyperthermia (mEHT) is a form of hyperthermia used in cancer treatment. mEHT has demonstrated the ability to activate host immunity by inducing the release of heat shock proteins, triggering apoptosis, and destroying the integrity of cell membranes to enhance cellular uptake of chemo-drugs in tumor cells. Both curcumin and resveratrol are phytochemicals that function as effective antioxidants, immune activators, and potential inhibitors of tumor development. However, poor bioavailability is a major obstacle for use in clinical cancer treatment.MethodsThis purpose of this study was to investigate whether mEHT can increase anti-cancer efficacy of nanosized curcumin and resveratrol in in vitro and in vivo models. The in vitro study included cell proliferation assay, cell cycle, and apoptosis analysis. Serum concentration was analyzed for the absorption of curcumin and resveratrol in SD rat model. The in vivo CT26/BALB/c animal tumor model was used for validating the safety, tumor growth curve, and immune cell infiltration within tumor tissues after combined mEHT/curcumin/resveratrol treatment.ResultsThe results indicate co-treatment of mEHT with nano-curcumin and resveratrol significantly induced cell cycle arrest and apoptosis of CT26 cells. The serum concentrations of curcumin and resveratrol were significantly elevated when mEHT was applied. The combination also inhibited the growth of CT26 colon cancer by inducing apoptosis and HSP70 expression of tumor cells while recruiting CD3+ T-cells and F4/80+ macrophages.ConclusionsThe results of this study have suggested that this natural, non-toxic compound can be an effective anti-tumor strategy for clinical cancer therapy. mEHT can enable cellular uptake of potential anti-tumor materials and create a favorable tumor microenvironment for an immunological chain reaction that improves the success of combined treatments of curcumin and resveratrol.
A site-moiety map and virtual screening approach for discovery of novel 5-LOX inhibitors
(2020-06-29)
Hsu, Kai-Cheng
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HuangFu, Wei-Chun
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Lin, Tony Eight
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Chao, Min-Wu
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Sung, Tzu-Ying
The immune system works in conjunction with inflammation. Excessive inflammation underlies various human diseases, such as asthma, diabetes and heart disease. Previous studies found that 5-lipoxygenase (5-LOX) plays a crucial role in metabolizing arachidonic acid into inflammatory mediators and is a potential therapeutic target. In this study, we performed an in silico approach to establish a site-moiety map (SiMMap) to screen for new 5-LOX inhibitors. The map is composed of several anchors that contain key residues, moiety preferences, and their interaction types (i.e., electrostatic (E), hydrogen-bonding (H), and van der Waals (V) interactions) within the catalytic site. In total, we identified one EH, one H, and five V anchors, within the 5-LOX catalytic site. Based on the SiMMap, three 5-LOX inhibitors (YS1, YS2, and YS3) were identified. An enzyme-based assay validated inhibitory activity of YS1, YS2, and YS3 against 5-LOX with an IC50 value of 2.7, 4.2, and 5.3 mu M, respectively. All three inhibitors significantly decrease LPS-induced TNF-alpha and IL-6 production, which suggests its potential use an anti-inflammatory agent. In addition, the identified 5-LOX inhibitors contain a novel scaffold. The discovery of these inhibitors presents an opportunity for designing specific anti-inflammatory drugs.
Removal of an abluminal lining improves decellularization of human umbilical arteries
(2020-06-29)
Tuan-Mu, Ho-Yi
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Chang, Yi-Hao
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Hu, Jin-Jia
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機械工程學系
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Department of Mechanical Engineering
The decellularization of long segments of tubular tissues such as blood vessels may be improved by perfusing decellularization solution into their lumen. Particularly, transmural flow that may be introduced by the perfusion, if any, is beneficial to removing immunogenic cellular components in the vessel wall. When human umbilical arteries (HUAs) were perfused at a transmural pressure, however, very little transmural flow was observed. We hypothesized that a watertight lining at the abluminal surface of HUAs hampered the transmural flow and tested the hypothesis by subjecting the abluminal surface to enzyme digestion. Specifically, a highly viscous collagenase solution was applied onto the surface, thereby restricting the digestion to the surface. The localized digestion resulted in a water-permeable vessel without damaging the vessel wall. The presence of the abluminal lining and its successful removal were also supported by evidence from SEM, TEM, and mechanical testing. The collagenase-treated HUAs were decellularized with 1% sodium dodecyl sulfate (SDS) solution under either rotary agitation, simple perfusion, or pressurized perfusion. Regardless of decellularization conditions, the decellularization of HUAs was significantly enhanced after the abluminal lining removal. Particularly, complete removal of DNA was accomplished in 24 h by pressurized perfusion of the SDS solution. We conclude that the removal of the abluminal lining can improve the perfusion-assisted decellularization.
自信揚帆～身心障礙者就業服務資源介紹
(國立陽明大學, 2020-06-30)
劉容孜
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陽明電子報編輯小組
「摺」我的校門，拼一個回憶
(國立陽明大學, 2020-06-30)
陽明電子報編輯小組
今年是陽明大學45周年校慶，校友中心特別製作陽明校門紙模型紀念品，在校慶典禮致贈與會貴賓及校友。這次剛好有機會參與到整個設...
【校內商店暑假營業時間】
(國立陽明大學, 2020-06-30)
陽明電子報編輯小組
惠蓀咖啡：8:00-18:00（7月6日至8月31日） OK超
An Augmented Reality Head-Up Display System with a Wide-View Eyebox
(2020-06-30)
Wu, Pei-Jung
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Chuang, Chih-Hao
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Chen, Chien-Yu
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Wu, Jeng-Han
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Lin, Bor-Shyh
This study proposes to apply the combination of two 90-degree prisms and a holographic optical element to an image-dividing element, divide an image into three through the virtual image projection system, and accurately project the images to 160 cm behind the windshield. In order to distinguish the left image, middle image, and right image at the horizontal direction, the 90-degree prism is first utilized for horizontally deflecting the light, a holographic optical element is then used for presenting the vertical deflection of the image, and finally, the images are horizontally arranged as a real image on the diffuser. An image-dividing element is eventually integrated to the virtual image projection system. Then, the divided images are made as a virtual image which is projected to 160 cm behind the windshield to combine with the street scene. The horizontal angle of view of an eyebox is increased from 2.51 degrees to 7.22 degrees, and the size of the eyebox is 31.68 cm x 12.48 cm, allowing a wide-view laser-based head-up display with the large-angle beam-splitting function being successfully designed. It would not affect the field of view on the road, and this system could reduce the space and be arranged easily in a vehicle. Therefore, this proposed system is suitable for the aftermarket.
完成未竟的遺憾，田知學校友17年後再撥穗、一圓當年夢
(國立陽明大學, 2020-06-30)
陽明電子報編輯小組
今年的畢業典禮，陽明特別邀請振興醫院急診重症醫學部主任田知學校友出席。田校友是陽明醫學系92級畢業生，十七年前因遭逢SARS未
藥理所張婷婷、蔡秉興博士榮獲「科技部博後學術研究獎」
(國立陽明大學, 2020-06-30)
陽明電子報編輯小組
本校醫學院藥理學研究所張婷婷博士與蔡秉興博士，分別以糖尿病與基因治療方面的創新研究成果，榮獲科技部「108年度博士後研究人員.
齊賀母校校慶—校友回娘家
(國立陽明大學, 2020-06-30)
陽明電子報編輯小組
5月31日，在這個艷陽高照的星期天，45周年校慶展開多場熱鬧有趣的活動，更是一年一度、第19屆「校友回娘家」的大日子！雖受疫情影