Large-area and bright pulsed electroluminescence in monolayer semiconductors

KAUST Repository

Lien, Der-Hsien

2018-04-04

Transition-metal dichalcogenide monolayers have naturally terminated surfaces and can exhibit a near-unity photoluminescence quantum yield in the presence of suitable defect passivation. To date, steady-state monolayer light-emitting devices suffer from Schottky contacts or require complex heterostructures. We demonstrate a transient-mode electroluminescent device based on transition-metal dichalcogenide monolayers (MoS, WS, MoSe, and WSe) to overcome these problems. Electroluminescence from this dopant-free two-terminal device is obtained by applying an AC voltage between the gate and the semiconductor. Notably, the electroluminescence intensity is weakly dependent on the Schottky barrier height or polarity of the contact. We fabricate a monolayer seven-segment display and achieve the first transparent and bright millimeter-scale light-emitting monolayer semiconductor device.

Comparison of electroluminescence intensity and photocurrent of polymer based solar cells

Energy Technology Data Exchange (ETDEWEB)

Hoyer, Ulrich; Swonke, Thomas; Auer, Richard [Bayerisches Zentrum fuer Angewandte Energieforschung e.V., Erlangen (Germany); Pinna, Luigi; Brabec, Christoph J. [Bayerisches Zentrum fuer Angewandte Energieforschung e.V., Erlangen (Germany); I-MEET, University Erlangen (Germany); Stubhan, Tobias; Li, Ning [I-MEET, University Erlangen (Germany)

2011-11-15

The reciprocity theorem for solar cell predicts a linear relation between electroluminescence emission and photovoltaic quantum efficiency and an exponential dependence of the electroluminescence signal on the applied voltage. Both dependencies are experimentally verified for polymer based solar cells in this paper. Furthermore it is shown, that electroluminescence imaging of organic solar cells has the potential to visualize the photocurrent distribution significantly faster than standard laser beam induced current mapping (LBIC) techniques. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Hybrid electroluminescent devices

Science.gov (United States)

Shiang, Joseph John; Duggal, Anil Raj; Michael, Joseph Darryl

2010-08-03

A hybrid electroluminescent (EL) device comprises at least one inorganic diode element and at least one organic EL element that are electrically connected in series. The absolute value of the breakdown voltage of the inorganic diode element is greater than the absolute value of the maximum reverse bias voltage across the series. The inorganic diode element can be a power diode, a Schottky barrier diode, or a light-emitting diode.

Electroluminescence Efficiency Enhancement using Metal Nanoparticles

National Research Council Canada - National Science Library

Soref, Richard A; Khurgin, J. B; Sun, G

2008-01-01

We apply the "effective mode volume" theory to evaluate enhancement of the electroluminescence efficiency of semiconductor emitters placed in the vicinity of isolated metal nanoparticles and their arrays...

Novel Mechano-Luminescent Sensors Based on Piezoelectric/Electroluminescent Composites

Directory of Open Access Journals (Sweden)

Yunzhang Fang

2011-04-01

Full Text Available A high-sensitivity mechano-luminescent sensor was fabricated on the basis of piezoelectric/electroluminescent composites. The working principle of this mechano-luminescent sensor was elucidated by analyzing the relationship between the piezoelectric-induced charges and the electroluminescent effects. When a stress is applied on the piezoelectric layer, electrical charges will be induced at both the top and bottom sides of the piezoelectric layer. The induced electrical charges will lead to a light output from the electroluminescent layer, thus producing a mechano-luminescence effect. By increasing the vibration strength or frequency applied, the mechano-luminescence output can be obviously enhanced. Mechano-luminescence sensors have potential in smart stress-to-light devices, such as foot-stress-distribution-diagnosis systems and dynamic-load-monitors for bridge hanging cables.

A Stretchable Alternating Current Electroluminescent Fiber

Directory of Open Access Journals (Sweden)

Dan Hu

2018-01-01

Full Text Available Flexible, stretchable electroluminescent fibers are of significance to meet the escalating requirements of increasing complexity and multifunctionality of smart electronics. We report a stretchable alternating current electroluminescent (ACEL fiber by a low-cost and all solution-processed scalable process. The ACEL fiber provides high stretchability, decent light-emitting performance, with excellent stability and nearly zero hysteresis. It can be stretched up to 80% strain. Our ACEL fiber device maintained a stable luminance for over 6000 stretch-release cycles at 50% strain. The mechanical stretchability and optical stability of our ACEL fiber device provides new possibilities towards next-generation stretchable displays, electronic textiles, advanced biomedical imaging and lighting, conformable visual readouts in arbitrary shapes, and novel health-monitoring devices.

Photoluminescence and electroluminescence from Ge/strained GeSn/Ge quantum wells

Energy Technology Data Exchange (ETDEWEB)

Lin, Chung-Yi; Chang, Chih-Chiang [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan (China); Huang, Chih-Hsiung; Huang, Shih-Hsien [Department of Electrical Engineering, Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Liu, C. W., E-mail: chee@cc.ee.ntu.edu.tw [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan (China); Department of Electrical Engineering, Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan (China); National Nano Device Labs, Hsinchu 30077, Taiwan (China); Huang, Yi-Chiau; Chung, Hua; Chang, Chorng-Ping [Applied Materials Inc., Sunnyvale, California 94085 (United States)

2016-08-29

Ge/strained GeSn/Ge quantum wells are grown on a 300 mm Si substrate by chemical vapor deposition. The direct bandgap emission from strained GeSn is observed in the photoluminescence spectra and is enhanced by Al{sub 2}O{sub 3}/SiO{sub 2} passivation due to the field effect. The electroluminescence of the direct bandgap emission of strained GeSn is also observed from the Ni/Al{sub 2}O{sub 3}/GeSn metal-insulator-semiconductor tunneling diodes. Electroluminescence is a good indicator of GeSn material quality, since defects in GeSn layers degrade the electroluminescence intensity significantly. At the accumulation bias, the holes in the Ni gate electrode tunnel to the strained n-type GeSn layer through the ultrathin Al{sub 2}O{sub 3} and recombine radiatively with electrons. The emission wavelength of photoluminescence and electroluminescence can be tuned by the Sn content.

Influence of surface wettability on cathode electroluminescence of porous silicon

International Nuclear Information System (INIS)

Goryachev, D.N.; Sreseli, O.M.; Belyakov, L.V.

1997-01-01

Influence of porous silicon wettability on efficiency of its cathode electroluminescence in electrolytes was investigated. It was revealed that increase of porous silicon wettability by electrolyte improved contact with a sublayer and provided generation of sufficient quantity of charge carriers. Diffusion - ionic, not electronic mechanism of charge transfer to the centers of micro crystallite electroluminescence is observed in porous silicon - electrolyte systems

Charge transfer through amino groups-small molecules interface improving the performance of electroluminescent devices

Science.gov (United States)

Havare, Ali Kemal; Can, Mustafa; Tozlu, Cem; Kus, Mahmut; Okur, Salih; Demic, Şerafettin; Demirak, Kadir; Kurt, Mustafa; Icli, Sıddık

2016-05-01

A carboxylic group functioned charge transporting was synthesized and self-assembled on an indium tin oxide (ITO) anode. A typical electroluminescent device [modified ITO/TPD (50 nm)/Alq3 (60 nm)/LiF (2 nm)/(120 nm)] was fabricated to investigate the effect of the amino groups-small molecules interface on the characteristics of the device. The increase in the surface work function of ITO is expected to facilitate the hole injection from the ITO anode to the Hole Transport Layer (HTL) in electroluminescence. The modified electroluminescent device could endure a higher current and showed a much higher luminance than the nonmodified one. For the produced electroluminescent devices, the I-V characteristics, optical characterization and quantum yields were performed. The external quantum efficiency of the modified electroluminescent device is improved as the result of the presence of the amino groups-small molecules interface.

Yellow-green electroluminescence of samarium complexes of 8-hydroxyquinoline

Energy Technology Data Exchange (ETDEWEB)

Behzad, Sara Karimi; Najafi, Ezzatollah [Department of Chemistry Shahid Beheshti University G.C., Tehran 1983963113 (Iran, Islamic Republic of); Amini, Mostafa M., E-mail: m-pouramini@sbu.ac.ir [Department of Chemistry Shahid Beheshti University G.C., Tehran 1983963113 (Iran, Islamic Republic of); Janghouri, Mohammad; Mohajerani, Ezeddin [Laser Research Institute Shahid Beheshti University G.C., Tehran 1983963113 (Iran, Islamic Republic of); Ng, Seik Weng [Department of Chemistry, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2014-12-15

Four novel samarium complexes were prepared by reacting samarium(III) nitrate with 8-hydroxyquinoline, 2-methyl-8-hydroxyquinoline, and 1,10-phenanthroline and utilized as emitting materials in the electroluminescence device. All complexes were characterized by elemental analysis, infrared, UV–vis and {sup 1}H NMR spectroscopes and the molecular structure of a representative complex, [Sm{sub 2}(Me-HQ){sub 4}(NO{sub 3}){sub 6}] (1), was determined by single-crystal X-ray diffraction. Utilization of a π-conjugated (phenanthroline) ligand as a second ligand in the structure of the samarium complexes resulted in red shifts in both absorption and fluorescence spectra of complexes and moderately enhanced the photoluminescence intensity and the fluorescence quantum yield. The maximum emission peaks showed that a good correlation exists between the nature of the substituent group on the 8-hydroxyquinoline and the addition of the π-conjugated ligand in the structure of samarium complexes and emission wavelength. Devices with samarium(III) complexes with structure of ITO/PEDOT:PSS (90 nm)/PVK:PBD:Sm(III) complexes (75 nm)/Al (180 nm) were fabricated. In the electroluminescence (EL) spectra of the devices, a strong ligand-centered emission and narrow bands arising from the {sup 4}G{sub 5/2}→{sup 6}H{sub J} transitions (J=7/2, 9/2, and 11/2) of the samarium ion were observed for the complexes. The electroluminescent spectra of the samarium complexes were red-shifted as compared with the PVK:PBD blend. We believe that the electroluminescence performance of OLED devices based on samarium complexes relies on overlaps between the absorption of the samarium compounds and the emission of PVK:PBD. This revealed that it is possible to evaluate the electroluminescence performance of the samarium compounds-doped OLED devices based on the emission of PVK:PBD and the absorption of the dopants. - Highlights: • Four novel photoluminescence samarium complexes have been synthesized. �

Room-temperature electroluminescence of Er-doped hydrogenated amorphous silicon

Energy Technology Data Exchange (ETDEWEB)

Gusev, Oleg; Bresler, Mikhail; Kuznetsov, Alexey; Kudoyarova, Vera; Pak, Petr; Terukov, Evgenii; Tsendin, Konstantin; Yassievich, Irina [A F Ioffe Physico-Technical Institute, Politekhnicheskaya 26, 194021 St. Petersburg (Russian Federation); Fuhs, Walther [Hahn-Meitner Institut, Abteilung Photovoltaik, Rudower Chaussee 5, D-12489 Berlin (Germany); Weiser, Gerhard [Phillips-Universitat Marburg, Fachbereich Physik, D-35032 Marburg (Germany)

1998-05-11

We have observed room-temperature erbium-ion electroluminescence in erbium-doped amorphous silicon. Electrical conduction through the structure is controlled by thermally activated ionization of deep D{sup -} defects in an electric field and the reverse process of capture of mobile electrons by D{sup 0} states. Defect-related Auger excitation (DRAE) is responsible for excitation of erbium ions located close to dangling-bond defects. Our experimental data are consistent with the mechanisms proposed

Plasmonic enhancement of electroluminescence

Science.gov (United States)

Guzatov, D. V.; Gaponenko, S. V.; Demir, H. V.

2018-01-01

Here plasmonic effect specifically on electroluminescence (EL) is studied in terms of radiative and nonradiative decay rates for a dipole near a metal spherical nanoparticle (NP). Contribution from scattering is taken into account and is shown to play a decisive role in EL enhancement owing to pronounced size-dependent radiative decay enhancement and weak size effect on non-radiative counterpart. Unlike photoluminescence where local incident field factor mainly determines the enhancement possibility and level, EL enhancement is only possible by means of quantum yield rise, EL enhancement being feasible only for an intrinsic quantum yield Q0 red-orange range only. Independently of positive effect on quantum yield, metal nanoparticles embedded in an electroluminescent device will improve its efficiency at high currents owing to enhanced overall recombination rate which will diminish manifestation of Auger processes. The latter are believed to be responsible for the known undesirable efficiency droop in semiconductor commercial quantum well based LEDs at higher current. For the same reason plasmonics can diminish quantum dot photodegradation from Auger process induced non-radiative recombination and photoionization thus opening a way to avoid negative Auger effects in emerging colloidal semiconductor LEDs.

Organic Electroluminescent Sensor for Pressure Measurement

Directory of Open Access Journals (Sweden)

Tomohide Niimi

2012-10-01

Full Text Available We have proposed a novel concept of a pressure sensor called electroluminescent pressure sensor (ELPS based on oxygen quenching of electroluminescence. The sensor was fabricated as an organic light-emitting device (OLED with phosphorescent dyes whose phosphorescence can be quenched by oxygenmolecules, and with a polymer electrode which permeates oxygen molecules. The sensor was a single-layer OLED with Platinum (II octaethylporphine (PtOEP doped into poly(vinylcarbazole (PVK as an oxygen sensitive emissive layer and poly(3,4-ethylenedioxythiophene mixed with poly(styrenesulfonate (PEDOT:PSS as an oxygen permeating polymer anode. The pressure sensitivity of the fabricated ELPS sample was equivalent to that of the sensor excited by an illumination light source. Moreover, the pressure sensitivity of the sensor is equivalent to that of conventional pressure-sensitive paint (PSP, which is an optical pressure sensor based on photoluminescence.

Electroluminescent properties of an electrochemically cross-linkable carbazole peripheral poly(benzyl ether) dendrimer.

Science.gov (United States)

Park, Jin Young; Kim, Dong-Eun; Ponnapati, Ramakrishna; Kim, Jong-Min; Kwon, Young-Soo; Advincula, Rigoberto C

2011-04-04

The electroluminescent (EL) properties of a cross-linkable carbazole-terminated poly(benzyl ether) dendrimer, G(3)-cbz DN, doped into a PVK:PBD host matrix with a double-layer device configuration are investigated. Different concentrations of the guest material can control device efficiency, related to chromaticity of white emission and the origin of excited-state complexes occurring between hole-transporting carbazole units (PVK or G(3)-cbz DN) and electron-transporting oxadiazole (PBD). Two excited states (exciplex and electroplex) generated at the interfaces of PVK/G(3)-cbz DN and PBD result in competitive emission, exhibiting a broad band in the EL spectra. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electroluminescence of colloidal ZnSe quantum dots

International Nuclear Information System (INIS)

Dey, S.C.; Nath, S.S.

2011-01-01

The article reports a green chemical synthesis of colloidal ZnSe quantum dots at a moderate temperature. The prepared colloid sample is characterised by UV-vis absorption spectroscopy and transmission electron microscopy. UV-vis spectroscopy reveals as-expected blue-shift with strong absorption edge at 400 nm and micrographs show a non-uniform size distribution of ZnSe quantum dots in the range 1-4 nm. Further, photoluminescence and electroluminescence spectroscopies are carried out to study optical emission. Each of the spectroscopies reveals two emission peaks, indicating band-to-band transition and defect related transition. From the luminescence studies, it can be inferred that the recombination of electrons and holes resulting from interband transition causes violet emission and the recombination of a photon generated hole with a charged state of Zn-vacancy gives blue emission. Meanwhile electroluminescence study suggests the application of ZnSe quantum dots as an efficient light emitting device with the advantage of colour tuning (violet-blue-violet). - Highlights: → Synthesis of ZnSe quantum dots by a green chemical route. → Characterisation: UV-vis absorption spectroscopy and transmission electron microscopy. → Analysis of UV-vis absorption spectrum and transmission electron micrographs. → Study of electro-optical properties by photoluminescence and electroluminescence. → Conclusion: ZnSe quantum dots can be used as LED with dual colour emission.

Organic solution-processible electroluminescent molecular glasses for non-doped standard red OLEDs with electrically stable chromaticity

Energy Technology Data Exchange (ETDEWEB)

Bi, Xiaoman; Zuo, Weiwei; Liu, Yingliang, E-mail: liuylxn@sohu.com; Zhang, Zhenru; Zeng, Cen; Xu, Shengang; Cao, Shaokui, E-mail: caoshaokui@zzu.edu.cn

2015-10-15

Highlights: • The D–A–D electroluminescent molecular glasses are synthesized. • Non-doped red electroluminescent film is fabricated by spin-coating. • Red OLED shows stable wavelength, luminous efficiency and chromaticity. • CIE1931 coordinate is in accord with standard red light in PAL system. - Abstract: Organic light-emitting molecular glasses (OEMGs) are synthesized through the introduction of nonplanar donor and branched aliphatic chain into electroluminescent emitters. The target OEMGs are characterized by {sup 1}H NMR, {sup 13}C NMR, IR, UV–vis and fluorescent spectra as well as elemental analysis, TG and DSC. The results indicated that the optical, electrochemical and electroluminescent properties of OEMGs are adjusted successfully by the replacement of electron-donating group. The non-doped OLED device with a standard red electroluminescent emission is achieved by spin-coating the THF solution of OEMG with a triphenylamine moiety. This non-doped red OLED device takes on an electrically stable electroluminescent performance, including the stable maximum electroluminescent wavelength of 640 nm, the stable luminous efficiency of 2.4 cd/A and the stable CIE1931 coordinate of (x, y) = (0.64, 0.35), which is basically in accord with the CIE1931 coordinate (x, y) = (0.64, 0.33) of standard red light in PAL system.

Tunneling electron induced molecular electroluminescence from individual porphyrin J-aggregates

Energy Technology Data Exchange (ETDEWEB)

Meng, Qiushi; Zhang, Chao; Zhang, Yang, E-mail: zhyangnano@ustc.edu.cn, E-mail: zcdong@ustc.edu.cn; Zhang, Yao; Liao, Yuan; Dong, Zhenchao, E-mail: zhyangnano@ustc.edu.cn, E-mail: zcdong@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2015-07-27

We investigate molecular electroluminescence from individual tubular porphyrin J-aggregates on Au(111) by tunneling electron excitations in an ultrahigh-vacuum scanning tunneling microscope (STM). High-resolution STM images suggest a spiral tubular structure for the porphyrin J-aggregate with highly ordered “brickwork”-like arrangements. Such aggregated nanotube is found to behave like a self-decoupled molecular architecture and shows red-shifted electroluminescence characteristics of J-aggregates originated from the delocalized excitons. The positions of the emission peaks are found to shift slightly depending on the excitation sites, which, together with the changes in the observed spectral profiles with vibronic progressions, suggest a limited exciton coherence number within several molecules. The J-aggregate electroluminescence is also found unipolar, occurring only at negative sample voltages, which is presumably related to the junction asymmetry in the context of molecular excitations via the carrier injection mechanism.

Coordination compounds of rare-earth metals with organic ligands for electroluminescent diodes

International Nuclear Information System (INIS)

Katkova, M A; Bochkarev, Mikhail N; Vitukhnovsky, Alexey G

2005-01-01

Data on lanthanide coordination compounds with organic ligands used in the design of electroluminescent diodes are summarised and systematically represented. The molecular and electronic structures and spectroscopic characteristics of these compounds are considered. A comparative analysis of the properties of organic electroluminescent diodes with different compositions of emitting and conductive layers is presented.

Large magneto-conductance and magneto-electroluminescence in exciplex-based organic light-emitting diodes at room temperature

Science.gov (United States)

Ling, Yongzhou; Lei, Yanlian; Zhang, Qiaoming; Chen, Lixiang; Song, Qunliang; Xiong, Zuhong

2015-11-01

In this work, we report on large magneto-conductance (MC) over 60% and magneto-electroluminescence (MEL) as high as 112% at room temperature in an exciplex-based organic light-emitting diode (OLED) with efficient reverse intersystem crossing (ISC). The large MC and MEL are individually confirmed by the current density-voltage characteristics and the electroluminescence spectra under various magnetic fields. We proposed that this type of magnetic field effect (MFE) is governed by the field-modulated reverse ISC between the singlet and triplet exciplex. The temperature-dependent MFEs reveal that the small activation energy of reverse ISC accounts for the large MFEs in the present exciplex-based OLEDs.

Electroluminescence and phototrigger effect in single crystals of GaSxSe1-x alloys

International Nuclear Information System (INIS)

Kyazym-Zade, A. G.; Salmanov, V. M.; Mokhtari, A. G.; Dadashova, V. V.; Agaeva, A. A.

2008-01-01

The effects of switching and electroluminescence as well as the interrelation between these effects in single crystals of GaS x Se 1-x alloys are detected and studied. It is established that the threshold voltage for switching depends on temperature, resistivity, and composition of alloys, and also on the intensity and spectrum of photoactive light. As a result, a phototrigger effect is observed; this effect arises under irradiation with light from the fundamental-absorption region. Electroluminescence is observed in the subthreshold region of the current-voltage characteristic; the electroluminescence intensity decreases drastically to zero as the sample is switched from a high-resistivity state to a low-resistivity state. Experimental data indicating that the electroluminescence and the switching effect are based on the injection mechanism (as it takes place in other layered crystals of the III-V type) are reported

Correlation of AlGaN/GaN high-electron-mobility transistors electroluminescence characteristics with current collapse

Science.gov (United States)

Ohi, Shintaro; Yamazaki, Taisei; Asubar, Joel T.; Tokuda, Hirokuni; Kuzuhara, Masaaki

2018-02-01

We report on the correlation between the electroluminescence and current collapse of AlGaN/GaN high-electron-mobility transistors (HEMTs). Standard passivated devices suffering from severe current collapse exhibited high-intensity whitish electroluminescence confined near the drain contact. In contrast, devices with reduced current collapse resulting from oxygen plasma treatment or GaN capping showed low-intensity reddish emission across the entire gate-drain access region. A qualitative explanation of this observed correlation between the current collapse and electroluminescence is presented. Our results demonstrate that electroluminescence analysis is a powerful tool not only for identifying high-field regions but also for assessing the degree of current collapse in AlGaN/GaN HEMTs.

Double peak spectra in spontaneous edge electroluminescence

Czech Academy of Sciences Publication Activity Database

Zavadil, Jiří; Žďánský, Karel

1993-01-01

Roč. 36, č. 11 (1993), s. 1623-1632 ISSN 0038-1101 R&D Projects: GA AV ČR IAA167108 Keywords : light emitting diodes * electroluminescence * optical waveguide theory Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.871, year: 1993

Photovoltaic and Electroluminescence Characters in Hybrid ZnO and Conjugated Polymer Bulk Heterojunction Devices

Institute of Scientific and Technical Information of China (English)

LIU Jun-Peng; QU Sheng-Chun; XU Ying; CHEN Yong-Hai; ZENG Xiang-Bo; WANG Zhi-Jie; ZHOU Hui-Ying; WANG Zhan-Guo

2007-01-01

We report electroluminescence in hybrid ZnO and conjugated polymer poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) bulk heterojunction photovoltaic cells. Photoluminescence quenching experimental results indicate that the ultrafast photoinduced electron transfer occurs from MDMO-PPV to ZnO under illumination. The ultrafast photoinduced electron transfer effect is induced because ZnO has an electron affinity about 1.2 eV greater than that of MDMO-PPV. Electron 'back transfer' can occur if the interfacial barrier between ZnO and MDMO-PPV can be overcome by applying a substantial electric field. Therefore, electroluminescence action due to the fact that the back transfer effect can be observed in the ZnO: MDMO-PPV devices since a forward bias is applied. The photovoltaic and electroluminescence actions in the same ZnO: MDMO-PPV device can be induced by different injection ways: photoinjection and electrical injection. The devices are expected to provide an opportunity for dual functionality devices with photovoltaic effect and electroluminescence character.

Silicon nanowire hot carrier electroluminescence

Energy Technology Data Exchange (ETDEWEB)

Plessis, M. du, E-mail: monuko@up.ac.za; Joubert, T.-H.

2016-08-31

Avalanche electroluminescence from silicon pn junctions has been known for many years. However, the internal quantum efficiencies of these devices are quite low due to the indirect band gap nature of the semiconductor material. In this study we have used reach-through biasing and SOI (silicon-on-insulator) thin film structures to improve the internal power efficiency and the external light extraction efficiency. Both continuous silicon thin film pn junctions and parallel nanowire pn junctions were manufactured using a custom SOI technology. The pn junctions are operated in the reach-through mode of operation, thus increasing the average electric field within the fully depleted region. Experimental results of the emission spectrum indicate that the most dominant photon generating mechanism is due to intraband hot carrier relaxation processes. It was found that the SOI nanowire light source external power efficiency is at least an order of magnitude better than the comparable bulk CMOS (Complementary Metal Oxide Semiconductor) light source. - Highlights: • We investigate effect of electric field on silicon avalanche electroluminescence. • With reach-through pn junctions the current and carrier densities are kept constant. • Higher electric fields increase short wavelength radiation. • Higher electric fields decrease long wavelength radiation. • The effect of the electric field indicates intraband transitions as main mechanism.

Phosphorescent rhenium emitters based on two electron-withdrawing diamine ligands: Structure, characterization and electroluminescent performance

Energy Technology Data Exchange (ETDEWEB)

Rui, Mei, E-mail: meirui2015@163.com [College of Science, Hebei North University, Zhangjiakou 075000, Hebei (China); Yuhong, Wang [College of Science, Hebei North University, Zhangjiakou 075000, Hebei (China); Yinting, Wang; Na, Zhang [Communication Training Base of The Headquarters of The General Staff, Zhangjiakou 075100, Hebei (China)

2014-09-15

In this paper, two diamine ligands having electron-withdrawing oxadiazole group and their corresponding Re(I) complexes were synthesized. Their geometric structure, electronic transition, photophysical property, thermal stability and electrochemical property were discussed in detail. Experimental data suggested that both complexes were promising yellow emitters with suited energy levels and good thermal stability for electroluminescent application. The correlation between emission performance and electron-withdrawing group was analyzed. It was found that electron-withdrawing group favored emission performance improvement. Their electroluminescence performance was also explored. Yellow electroluminescence was observed with maximum brightness of 1743 cd/m{sup 2}. - Highlights: • Oxadiazole derived diamine ligands and their Re(I) complexes were synthesized. • Their characters and properties were analyzed and compared in detail. • Electron-withdrawing group was proved to be positive for PL improvement. • Electroluminescence was obtained with maximum brightness of 1743 cd/m{sup 2}.

Low temperature transient response and electroluminescence characteristics of OLEDs based on Alq3

Science.gov (United States)

Yuan, Chao; Guan, Min; Zhang, Yang; Li, Yiyang; Liu, Shuangjie; Zeng, Yiping

2017-08-01

In this work, the organic light-emitting diodes (OLEDs) based on Alq3 are fabricated. In order to make clear the transport mechanism of carriers in organic light-emitting devices at low temperature, detailed electroluminescence transient response and the current-voltage-luminescence (I-V-L) characteristics under different temperatures in those OLEDs are investigated. It founds that the acceleration of brightness increases with increasing temperature is maximum when the temperature is 200 K and it is mainly affected by the electron transport layer (Alq3). The MoO3 injection layer and the electroluminescent layer have great influence on the delay time when the temperature is 200 K. Once the temperature is greater than 250 K, the delay time is mainly affected by the MoO3 injection layer. On the contrary, the fall time is mainly affected by the electroluminescent material. The Vf is the average growth rate of fall time when the temperature increases 1 K which represents the accumulation rate of carriers. The difference between Vf caused by the MoO3 injection layer is 0.52 us/K and caused by the electroluminescent material Ir(ppy)3 is 0.73 us/K.

Influences on the white emission and stability of single layer electroluminescent devices

International Nuclear Information System (INIS)

Tekin, Emine

2013-01-01

A detailed survey about the influences on the white emission color of polyfluorene based polymer light emitting diodes (PLEDs) is reported. First, the effect of active layer thickness was studied. Subsequently keeping the polymer thickness at optimum level, PLEDs were fabricated varying polymer concentrations. All fabricated devices were fully characterized in terms of luminance, current–voltage characteristics, efficiencies, electroluminescent spectra, and CIE color coordinates. It was found that at higher polymer concentrations, electroluminescence spectra shifted to the bathochromic region so that the resulting color becomes warm white. Furthermore, the accelerated lifetimes of the PLEDs were measured and the results are discussed in terms of polymer inter-chain interactions. Consequently, the 8 mg/ml was found to be the optimum level not only for the device performances but also for the device lifetime. Highlights: • Influences on the white color emission of the polymer OLEDs were investigated. • White emission purity was found to be affected by the polymer concentration. • Lifetimes of the white emitting devices depend on the inter-chain interactions

Effect of γ-quanta on electroluminescent emitters with zinc sulfide luminophores

International Nuclear Information System (INIS)

Vershchagin, I.K.; Kokin, S.M.; Pautkina, A.V.

1993-01-01

The electroluminescent light sources used in data processing systems can operate under various conditions, particularly in the presence of a significant background radiation. In this work, the authors have investigated the effect of γ-irradiation on the main properties of electroluminescent emitters (ELE) prepared from polycrystalline luminophores of various grades. Such emitters are plane structures consisting of transparent and opaque electrodes and a layer of the luminophore distributed in the dielectric. The ELE were excited with a sinusoidal voltage (220 V; 0.4-1 kHz) at room temperature

Enhanced luminance for inorganic electroluminescent devices with a charged electret

Energy Technology Data Exchange (ETDEWEB)

Wang, Fang-Hsing, E-mail: fansen@dragon.nchu.edu.tw [Department of Electrical Engineering and Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung 402, Taiwan, ROC (China); Chen, Kuo-Feng [Department of Electrical Engineering and Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung 402, Taiwan, ROC (China); Display Technology Center/Industrial Technology Research Institute, Hsinchu 310, Taiwan, ROC (China); Chien, Yu-Han; Chang, Chin-Chia; Chuang, Meng-Ying [Display Technology Center/Industrial Technology Research Institute, Hsinchu 310, Taiwan, ROC (China)

2013-09-15

This work proposes a novel inorganic electroluminescent (IEL) device with an electric field built-in (EFBI) technique to reduce its driving voltage and enhance its luminance. The EFBI technique was performed by charging an electret comprising a silicon dioxide film at different temperatures (25–150 °C) in powder electroluminescent (PDEL) devices. The driving voltage of the EFBI-PDEL device decreased by 61.4 V (or 20.5%) under the brightness of 269 cd/m{sup 2}, and its brightness increased by 128 cd/m{sup 2} (or 47%) at ac 300 V. The efficiency of the EFBI-PDEL device significantly increased by 0.827 lm/W (or 45.5%) at ac 300 V. The proposed EFBI-PDEL device has advantages of a low-temperature process and low cost, and potential for large-area display applications. -- Highlights: • An electric-field built-in powder electroluminescent (EFBI-PDEL) device is proposed. • The EFBI technique is performed by charging an electrets. • The driving voltage of the EFBI-PDEL device decreased by 20.5%. • The brightness of the EFBI-PDEL device increased by 47%. • The efficiency of the EFBI-PDEL device increased by 45.5%.

Electroluminescence Properties of IrQ(ppy)2 Dual-Emitter Organometallic Compound in Organic Light-Emitting Devices

Science.gov (United States)

Ciobotaru, Constantin Claudiu; Polosan, Silviu; Ciobotaru, Iulia Corina

2018-02-01

This paper reports the influence of the charge carrier mobility on the electroluminescent properties of a dual-emitter organometallic compound dispersed in two conjugated organic small-molecule host materials and embedded in organic light-emitting devices (OLEDs). The electroluminescent processes in OLEDs are strongly influenced by the host-guest interaction. The charge carrier mobility in the host material plays an important role in the electroluminescent processes but also depends on the triplet-triplet interaction with the organometallic compound. The low charge carrier mobility in 4,4'-bis( N-carbazolyl)-1,1'-biphenyl (CBP) host material reduces the electroluminescent processes, but they are slightly enhanced by the triplet-triplet exothermic charge transfer. The higher charge carrier mobility in the case of N, N'-bis(3-methylphenyl)- N, N'-diphenylbenzidine (TPD) host material influences the electroluminescent processes by the endothermic energy transfer at room temperature, which facilitates the triplet-triplet harvesting in the host-guest system. The excitation is transferred to the guest molecules by triplet-triplet interaction as a Dexter transfer, which occurs by endothermic transfer from the triplet exciton in the host to the triplet exciton in the guest.

Red electroluminescent process excited by hot holes in SrGa2S4:Ce, Mn thin film

International Nuclear Information System (INIS)

Tanaka, Katsu; Okamoto, Shinji

2009-01-01

This paper reports the first observation of red electroluminescence (EL) in SrGa 2 S 4 :Ce, Mn thin film. The EL spectrum consists of single broad emission band having a peak wavelength of 665 nm. The dominant EL decay time was 31 μs. The relationship between the applied voltage and the EL waveform was measured in single insulating thin film electroluminescent (TFEL) devices. An asymmetric EL waveform was observed in SrGa 2 S 4 :Ce, Mn TFEL devices under a rectangular applied voltage. The polarity of the EL waveform in these devices was different from the waveform in manganese-activated zinc sulfide ZnS:Mn devices. This indicates that hot holes excite the Mn 2+ ions to cause the red EL.

The Electroluminescence Mechanism of Solution-Processed TADF Emitter 4CzIPN Doped OLEDs Investigated by Transient Measurements

Directory of Open Access Journals (Sweden)

Peng Wang

2016-10-01

Full Text Available High efficiency, solution-processed, organic light emitting devices (OLEDs, using a thermally-activated delayed fluorescent (TADF emitter, 1,2,3,5-tetrakis(carbazol-9-yl-4,6-dicyanobenzene (4CzIPN, are fabricated, and the transient electroluminescence (EL decay of the device with a structure of [ITO/PEDOT: PSS/4CzIPN 5 wt % doped 4,40-N,N0-dicarbazolylbiphenyl(CBP/bis-4,6-(3,5-di-4-pyridylphenyl-2-methylpyrimidine (B4PyMPM/lithium fluoride (LiF/Al], is systematically studied. The results shed light on the dominant operating mechanism in TADF-based OLEDs. Electroluminescence in the host–guest system is mainly produced from the 4CzIPN emitter, rather than the exciplex host materials.

Electroluminescence efficiencies of erbium in silicon-based hosts

Energy Technology Data Exchange (ETDEWEB)

Cueff, Sébastien, E-mail: sebastien-cueff@brown.edu, E-mail: christophe.labbe@ensicaen.fr [Centre de Recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252 CNRS/CEA/Ensicaen/UCBN, Caen 14050 (France); School of Engineering, Brown University, Providence, Rhode Island 02912 (United States); Manel Ramírez, Joan; Berencén, Yonder; Garrido, Blas [MIND-IN2UB, Department Electrònica, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028 (Spain); Kurvits, Jonathan A.; Zia, Rashid [School of Engineering, Brown University, Providence, Rhode Island 02912 (United States); Department of Physics, Brown University, Providence, Rhode Island 02912 (United States); Rizk, Richard; Labbé, Christophe, E-mail: sebastien-cueff@brown.edu, E-mail: christophe.labbe@ensicaen.fr [Centre de Recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252 CNRS/CEA/Ensicaen/UCBN, Caen 14050 (France)

2013-11-04

We report on room-temperature 1.5 μm electroluminescence from trivalent erbium (Er{sup 3+}) ions embedded in three different CMOS-compatible silicon-based hosts: SiO{sub 2}, Si{sub 3}N{sub 4}, and SiN{sub x}. We show that although the insertion of either nitrogen or excess silicon helps enhance electrical conduction and reduce the onset voltage for electroluminescence, it drastically decreases the external quantum efficiency of Er{sup 3+} ions from 2% in SiO{sub 2} to 0.001% and 0.0004% in SiN{sub x} and Si{sub 3}N{sub 4}, respectively. Furthermore, we present strong evidence that hot carrier injection is significantly more efficient than defect-assisted conduction for the electrical excitation of Er{sup 3+} ions. These results suggest strategies to optimize the engineering of on-chip electrically excited silicon-based nanophotonic light sources.

Electroluminescence of erbium in Al/α-Si:H(Er)/p-c-Si/Al structure

International Nuclear Information System (INIS)

Kon'kov, I.O.; Kuznetsov, A.N.; Pak, P.E.; Terukov, E.I.; Granitsyna, L.S.

2001-01-01

It is informed for the first time on the observation of the erbium intensive electroluminescence from the amorphous hydrated silicon layer by application of the Al/α-Si:H(Er)/p-c-Si/Al structure in the direct shift mode. The above structure is the n-p-heterostructure with the barrier values of 0.3-0.4 eV for the electrons and 0.9-1.1 eV for the holes. The electroluminescence efficiency is evaluated at the level ∼ 2 x 10 -5 . The electroluminescence effect in the Al/α-Si:H(Er)/p-c-Si/Al structure is connected with the hole tunneling from the crystal silicon by the amorphous silicon localized states with the subsequent release into the valent zone [ru

The synthesis and study of new electroluminescent materials

International Nuclear Information System (INIS)

Pillow, J.

1998-01-01

Dendrimers offer many potential advantages over other organic electroluminescent materials that have been developed for use in light emitting diodes. This thesis describes the preparation of new electroluminescent dendrimers that consist of a luminescent core, charge-transporting stilbene dendrons and solubilising t-butyl surface groups. Choosing the core to have a longer conjugation length than the dendrons establishes an energy gradient that ensures that light emission occurs from the dendrimer core. Two convergent syntheses were developed for the preparation of dendrons that had aldehyde, bromide and styryl focal groups. The Heck reaction between styrene focused dendrons and 3,5-dibromoaryls was used to increase the dendron generation. This reaction was then alternated with the Wittig or Stille reactions in an iterative cycle to prepare dendrons of up to the third generation. The luminescent cores were chosen to be 1,4-distyrylbenzene, 1,4-distyrylanthracene and meso-tetraaryl porphyrin to emit blue, green and red light respectively. Dendrimers up to the third generation were prepared containing these cores. Further control over the emission colour was demonstrated by the chelation of metals into the porphyrin core. Computer modelling was used to predict the conformations of the dendrimers, with confirmation provided by GPC and X-ray crystallography. The modelled structures were then used to interpret the photoluminescence and electroluminescence spectra. Electrochemical analyses allowed the comparison of the HOMO and LUMO energy levels with the Fermi levels of the metal electrodes, which was used to explain the behaviour of the dendrimers in single layer light-emitting diodes. (author)

Carbon-electroluminescence: An organic approach to lighting

Science.gov (United States)

Kumari, Sonali; Chaudhary, Tarun; Chandran, Vivek; Lokeshwari, M.; Shastry, K.

2018-05-01

Over the recent years, quantum dots have garnered massive following and peaked in interest among the scientific community due to their versatility, exotic properties, ease of preparation and low cost. As the demand for faster, reliable and energy efficient electronic devices intensifies, extra emphasis is laid on the development of smart materials capable of satiating this need. Electroluminescent organic quantum dots have emerged as one of the prime contenders in addressing the ecological, economic and technological constraints. Application of such luminescent nanoparticles as fluorescent light converters in LEDs is touted as one of the reliable and easiest avenues in realizing and developing newer energy efficient technologies for the next millennia. One promising candidate is zig-zag graphene quantum dots, which exhibits high electro-luminescence due to a phenomenon known as quantum confinement (where size of the nano-particle is of the same order or less than that of Bohr exciton radius). In this paper, we aim to provide a review of past and present research in the synthesis and development of luminescence using organic quantum dots.

Functional electronic screen printing – electroluminescent smart fabric watch

OpenAIRE

de Vos, Marc; Torah, Russel; Beeby, Steve; Tudor, John

2013-01-01

Motivation for screen printed smart fabrics.Introduce functional electronic screen printing on fabrics.Printed smart fabric watch design.Printing process for electroluminescent watch.Demonstration video.Conclusions and further work.Examples of other screen printed smart fabrics.

Flexible powder electroluminescent device on silver nanowire electrode

International Nuclear Information System (INIS)

Park, K.W.; Jeong, H.S.; Park, J.H.; Deressa, G.; Jeong, Y.T.; Lim, K.T.; Park, J.H.; Lee, S.H.; Kim, J.S.

2015-01-01

We have demonstrated the flexible AC powder electroluminescent device based on Ag nanowire electrode. The Ag nanowire electrode showed the nanowire morphology of 20 nm in diameter and 15 μm in length, the transmittance of 87%, and the sheet resistance of 50 Ω/sq, and the higher flexibility than the conventional ITO substrate. The electroluminescence spectra of the Ag nanowire-based device in all frequency and voltage ranges were almost similar with the ITO-based device. In comparison with the ITO-based device, the luminous efficiency of the Ag nanowire-based device was almost same as 1.53 lm/W. - Highlights: • Flexibility of Ag NW substrate was higher than ITO substrate. • EL intensity of Ag NW-based EL device was almost similar with ITO-based EL device. • Charge density and turn-on voltage of Ag NW-based EL device were a little larger than ITO-based EL device

Flexible powder electroluminescent device on silver nanowire electrode

Energy Technology Data Exchange (ETDEWEB)

Park, K.W.; Jeong, H.S.; Park, J.H.; Deressa, G.; Jeong, Y.T.; Lim, K.T. [Department of Display Science and Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Park, J.H. [AIDEN company, Cheongju-si 361-911 (Korea, Republic of); Lee, S.H. [R& D Business Lab, Hyosung Corporation, Anyang 431-080 (Korea, Republic of); Kim, J.S., E-mail: jsukim@pknu.ac.kr [Department of Display Science and Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

2015-09-15

We have demonstrated the flexible AC powder electroluminescent device based on Ag nanowire electrode. The Ag nanowire electrode showed the nanowire morphology of 20 nm in diameter and 15 μm in length, the transmittance of 87%, and the sheet resistance of 50 Ω/sq, and the higher flexibility than the conventional ITO substrate. The electroluminescence spectra of the Ag nanowire-based device in all frequency and voltage ranges were almost similar with the ITO-based device. In comparison with the ITO-based device, the luminous efficiency of the Ag nanowire-based device was almost same as 1.53 lm/W. - Highlights: • Flexibility of Ag NW substrate was higher than ITO substrate. • EL intensity of Ag NW-based EL device was almost similar with ITO-based EL device. • Charge density and turn-on voltage of Ag NW-based EL device were a little larger than ITO-based EL device.

Photo- and electroluminescence of undoped and rare earth doped ZnO electroluminors

International Nuclear Information System (INIS)

Bhushan, S.; Pandey, A.N.; Kaza, B.R.

1977-01-01

A series of undoped and rare earth (Dy, Yb, Nd, Pr, Gd, La, Sm and Er) doped ZnO electroluminors have been prepared and their photo- (PL) and electroluminescence (EL) spectra at different concentrations of rare earth ions have been investigated. PL and EL spectra of undoped electroluminescence consist of three peaks. Due to the addition of the rare earth ions these peaks are shifted either to the longer or to the shorter wavelength side. The intensities are also either decreased or increased. Experimental results favour the donor-accepted model for this system. (Auth.)

Green–white electroluminescence and green photoluminescence of zinc complexes

Energy Technology Data Exchange (ETDEWEB)

Janghouri, Mohammad; Mohajerani, Ezeddin [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 1983963113 (Iran, Islamic Republic of); Amini, Mostafa M.; Najafi, Ezzatollah [Department of Chemistry, Shahid Beheshti University, G.C., Tehran 1983963113 (Iran, Islamic Republic of)

2014-10-15

A series of zinc complexes has been synthesized and utilized as fluorescent materials in organic light-emitting diodes (OLEDs). All prepared complexes were characterized by elemental analysis (CHN), UV–vis, FT-IR and {sup 1}H NMR spectroscopy. The energy levels of zinc complexes were determined by cyclic voltammetry measurements. Devices with fundamental structure of ITO/PVK:PBD (50 nm)/zinc complexes/BCP (5 nm)/Alq{sub 3} (25 nm)/Al (180 nm) were fabricated. A green electroluminescence was obtained from thin film complexes at 25 nm thickness. When thickness of the complex bis(2-methylquinolin-8-olato)-bis[(acetato)-(methanol)zinc(II)] (B) in thin film decreased from 25 nm to 20, 18, and 12 nm, a white electroluminescence obtained. The white emission which was composed of blue and green attributed to the PVK:PBD blend and thickness of complex, respectively. With 12 nm thickness of complex, a maximum luminance of 4530 cd/m{sup 2} at a current density 398.32 mA/cm{sup 2} with CIE coordinates of 0.22 and 0.36 at 20 V was achieved. - Highlights: • Several new zinc complexes have been synthesized and utilized as fluorescent materials in OLEDs. • Photoluminescence emission of zinc complexes showed a red shift in respect to PVK:PBD blend. • Green electroluminescence emission from zinc complexes was achieved. • White emission has been obtained for an OLED by changing thickness of the zinc complex.

Green–white electroluminescence and green photoluminescence of zinc complexes

International Nuclear Information System (INIS)

Janghouri, Mohammad; Mohajerani, Ezeddin; Amini, Mostafa M.; Najafi, Ezzatollah

2014-01-01

A series of zinc complexes has been synthesized and utilized as fluorescent materials in organic light-emitting diodes (OLEDs). All prepared complexes were characterized by elemental analysis (CHN), UV–vis, FT-IR and 1 H NMR spectroscopy. The energy levels of zinc complexes were determined by cyclic voltammetry measurements. Devices with fundamental structure of ITO/PVK:PBD (50 nm)/zinc complexes/BCP (5 nm)/Alq 3 (25 nm)/Al (180 nm) were fabricated. A green electroluminescence was obtained from thin film complexes at 25 nm thickness. When thickness of the complex bis(2-methylquinolin-8-olato)-bis[(acetato)-(methanol)zinc(II)] (B) in thin film decreased from 25 nm to 20, 18, and 12 nm, a white electroluminescence obtained. The white emission which was composed of blue and green attributed to the PVK:PBD blend and thickness of complex, respectively. With 12 nm thickness of complex, a maximum luminance of 4530 cd/m 2 at a current density 398.32 mA/cm 2 with CIE coordinates of 0.22 and 0.36 at 20 V was achieved. - Highlights: • Several new zinc complexes have been synthesized and utilized as fluorescent materials in OLEDs. • Photoluminescence emission of zinc complexes showed a red shift in respect to PVK:PBD blend. • Green electroluminescence emission from zinc complexes was achieved. • White emission has been obtained for an OLED by changing thickness of the zinc complex

Supporting Information Blue and White light electroluminescence in ...

Indian Academy of Sciences (India)

Administrator

Blue and White light electroluminescence in a multilayer OLED using a new Aluminium complex. Pabitra K. Nayak a. , Neeraj Agarwal a. , Farman Ali a. , Meghan P. Patankar b. , K. L.. Narasimhan b. *, N. Periasamy a. *. 1. Department of Chemical Sciences,. 2. Department of Condensed Matter Physics and. Materials ...

Electroluminescence from graphene excited by electron tunneling

International Nuclear Information System (INIS)

Beams, Ryan; Bharadwaj, Palash; Novotny, Lukas

2014-01-01

We use low-energy electron tunneling to excite electroluminescence in single layer graphene. Electrons are injected locally using a scanning tunneling microscope and the luminescence is analyzed using a wide-angle optical imaging system. The luminescence can be switched on and off by inverting the tip–sample bias voltage. The observed luminescence is explained in terms of a hot luminescence mechanism. (paper)

Efficient electroluminescence from a perylenediimide fluorophore obtained from a simple solution processed OLED

International Nuclear Information System (INIS)

Cespedes-Guirao, F J; Fernandez-Lazaro, F; Sastre-Santos, A; Garcia-Santamaria, S; Bolink, H J

2009-01-01

Simple solution processed organic light emitting diodes are used to screen the performance of two types of highly efficient, narrow band red emitting fluorescent perylenediimides (PDIs). PDIs substituted at the diimide positions seem to form aggregates in the thin film architecture as evidenced by the shifted electroluminescent spectrum. When substituted on the bay position and when used both as the emitting and the electron transporting specie, bright electroluminescence with a narrow width around 610 nm reaching 500 cd m -2 at moderate voltages was observed, demonstrating the usefulness of these fluorophores for OLED applications.

Electroluminescent TCC, C3dg and fB/Bb epitope assays for profiling complement cascade activation in vitro using an activated complement serum calibration standard.

Science.gov (United States)

van Vuuren, B Jansen; Bergseth, G; Mollnes, T E; Shaw, A M

2014-01-15

Electroluminescent assays for epitopes on the complement components C3dg, terminal complement complex (TCC) and factor B/Bb (fB/Bb) have been developed with capture and detection antibodies to produce detection limits C3dg=91±9ng/mL, TCC=3±0.1ng/mL and fB=55.7±0.1ng/mL. The assay performance was assessed against a series of zymosan and heat aggregated IgG (HAIgG) in vitro activations of complement using a calibrated activated complement serum (ACS) as calibration standard. The ACS standard was stable within 20% accuracy over a 6-month period with freeze-thaw cycles as required. Differential activation of the complement cascade was observed for TCC showing a pseudo-first order formation half-life of 3.5h after activation with zymosan. The C3dg activation fragment indicates a 10% total activation for both activation agents. The kinetic-epitope analysis for fB indicates that the capture epitope is on the fB/Bb protein fragment which can then become covered by the formation of C3bBb or C3bBbP complexes during the time course of the cascade. Copyright © 2013 Elsevier B.V. All rights reserved.

Dye linked conjugated homopolymers: using conjugated polymer electroluminescence to optically pump porphyrin-dye emission

DEFF Research Database (Denmark)

Nielsen, K.T.; Spanggaard, H.; Krebs, Frederik C

2004-01-01

. Electroluminescent devices of the homopolymer itself and of the zinc-porphyrin containing polymer were prepared and the nature of the electroluminescence was characterized. The homopolymer segments were found to optically pump the emission of the zinc-porphyrin dye moities. The homopolymer exhibits blue......Zinc-porphyrin dye molecules were incorporated into the backbone of a conjugated polymer material by a method, which allowed for the incorporation of only one zinc-porphyrin dye molecule into the backbone of each conjugated polymer molecule. The electronic properties of the homopolymer were...

Automatic Detection of Inactive Solar Cell Cracks in Electroluminescence Images

DEFF Research Database (Denmark)

Spataru, Sergiu; Hacke, Peter; Sera, Dezso

2017-01-01

We propose an algorithm for automatic determination of the electroluminescence (EL) signal threshold level corresponding to inactive solar cell cracks, resulting from their disconnection from the electrical circuit of the cell. The method enables automatic quantification of the cell crack size...

Electroluminescence from a diamond device with ion-beam-micromachined buried graphitic electrodes

Energy Technology Data Exchange (ETDEWEB)

Forneris, J., E-mail: jacopo.forneris@unito.it [Physics Department and NIS Interdepartmental Centre, University of Torino, Torino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sez. Torino, Torino (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Sez. Torino, Torino (Italy); Battiato, A.; Gatto Monticone, D. [Physics Department and NIS Interdepartmental Centre, University of Torino, Torino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sez. Torino, Torino (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Sez. Torino, Torino (Italy); Picollo, F. [Istituto Nazionale di Fisica Nucleare (INFN), Sez. Torino, Torino (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Sez. Torino, Torino (Italy); Physics Department and NIS Interdepartmental Centre, University of Torino, Torino (Italy); Amato, G.; Boarino, L.; Brida, G.; Degiovanni, I.P.; Enrico, E.; Genovese, M.; Moreva, E.; Traina, P. [Istituto Nazionale di Ricerca Metrologica (INRiM), Torino (Italy); Verona, C.; Verona Rinati, G. [Department of Industrial Engineering, University of Roma “Tor Vergata”, Roma (Italy); Olivero, P. [Physics Department and NIS Interdepartmental Centre, University of Torino, Torino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sez. Torino, Torino (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Sez. Torino, Torino (Italy)

2015-04-01

Focused MeV ion microbeams are suitable tools for the direct writing of conductive graphitic channels buried in an insulating diamond bulk, as demonstrated in previous works with the fabrication of multi-electrode ionizing radiation detectors and cellular biosensors. In this work we investigate the suitability of the fabrication method for the electrical excitation of color centers in diamond. Differently from photoluminescence, electroluminescence requires an electrical current flowing through the diamond sub-gap states for the excitation of the color centers. With this purpose, buried graphitic electrodes with a spacing of 10 μm were fabricated in the bulk of a detector-grade CVD single-crystal diamond sample using a scanning 1.8 MeV He{sup +} micro-beam. The current flowing in the gap region between the electrodes upon the application of a 450 V bias voltage was exploited as the excitation pump for the electroluminescence of different types of color centers localized in the above-mentioned gap. The bright light emission was spatially mapped using a confocal optical microscopy setup. The spectral analysis of electroluminescence revealed the emission from neutrally-charged nitrogen-vacancy centers (NV{sup 0}, λ{sub ZPL} = 575 nm), as well as from cluster crystal dislocations (A-band, λ = 400–500 nm). Moreover, an electroluminescence signal with appealing spectral features (sharp emission at room temperature, low phonon sidebands) from He-related defects was detected (λ{sub ZPL} = 536.3 nm, λ{sub ZPL} = 560.5 nm); a low and broad peak around λ = 740 nm was also observed and tentatively ascribed to Si-V or GR1 centers. These results pose interesting future perspectives for the fabrication of electrically-stimulated single-photon emitters in diamond for applications in quantum optics and quantum cryptography.

Electrodeposition of Metal Matrix Composites and Materials Characterization for Thin-Film Solar Cells

Science.gov (United States)

2017-12-04

Air Mass CNT Carbon Nanotubes DIV Dark Current -Voltage DMA Dynamic Mechanical Analysis EL Electroluminescence FEM Finite Element Method IMM...AFRL-RV-PS- AFRL-RV-PS- TR-2017-0174 TR-2017-0174 ELECTRODEPOSITION OF METAL MATRIX COMPOSITES AND MATERIALS CHARACTERIZATION FOR THIN-FILM SOLAR...research which is exempt from public affairs security and policy review in accordance with AFI 61-201, paragraph 2.3.5.1. This report is available to

Automatic Detection of Inactive Solar Cell Cracks in Electroluminescence Images

DEFF Research Database (Denmark)

Spataru, Sergiu; Hacke, Peter; Sera, Dezso

2017-01-01

We propose an algorithm for automatic determination of the electroluminescence (EL) signal threshold level corresponding to inactive solar cell cracks, resulting from their disconnection from the electrical circuit of the cell. The method enables automatic quantification of the cell crack size an...

Room-temperature low-voltage electroluminescence in amorphous carbon nitride thin films

Science.gov (United States)

Reyes, R.; Legnani, C.; Ribeiro Pinto, P. M.; Cremona, M.; de Araújo, P. J. G.; Achete, C. A.

2003-06-01

White-blue electroluminescent emission with a voltage bias less than 10 V was achieved in rf sputter-deposited amorphous carbon nitride (a-CN) and amorphous silicon carbon nitride (a-SiCN) thin-film-based devices. The heterojunction structures of these devices consist of: Indium tin oxide (ITO), used as a transparent anode; amorphous carbon film as an emission layer, and aluminum as a cathode. The thickness of the carbon films was about 250 Å. In all of the produced diodes, a stable visible emission peaked around 475 nm is observed at room temperature and the emission intensity increases with the current density. For an applied voltage of 14 V, the luminance was about 3 mCd/m2. The electroluminescent properties of the two devices are discussed and compared.

Magnetically modulated electroluminescence from hybrid organic/inorganic light-emitting diodes based on electron donor-acceptor exciplex blends

Science.gov (United States)

Pang, Zhiyong; Baniya, Sangita; Zhang, Chuang; Sun, Dali; Vardeny, Z. Valy

2016-03-01

We report room temperature magnetically modulated electroluminescence from a hybrid organic/inorganic light-emitting diode (h-OLED), in which an inorganic magnetic tunnel junction (MTJ) with large room temperature magnetoresistance is coupled to an N,N,N ',N '-Tetrakis(4-methoxyphenyl)benzidine (MeO-TPD): tris-[3-(3-pyridyl)mesityl]borane (3TPYMB) [D-A] based OLED that shows thermally activated delayed luminescence. The exciplex-based OLED provides two spin-mixing channels: upper energy channel of polaron pairs and lower energy channel of exciplexes. In operation, the large resistance mismatch between the MTJ and OLED components is suppressed due to the non-linear I-V characteristic of the OLED. This leads to enhanced giant magneto-electroluminescence (MEL) at room temperature. We measured MEL of ~ 75% at ambient conditions. Supported by SAMSUNG Global Research Outreach (GRO) program, and also by the NSF-Material Science & Engineering Center (MRSEC) program at the University of Utah (DMR-1121252).

Electroluminescence and photosensitivity spectra of organic diode structures based on zinc complexes

Science.gov (United States)

Kaplunov, M. G.; Krasnikova, S. S.; Nikitenko, S. L.; Yakushchenko, I. K.

2017-01-01

Devices based on zinc complexes with sulphanylaminosubstituted ligands are characterized by dual function - electroluminescence (EL) and photosensitivity. Both EL and photosensitivity are associated with the formation of exciplexes.

Enhancement of Electroluminescence (EL) image measurements for failure quantification methods

DEFF Research Database (Denmark)

Parikh, Harsh; Spataru, Sergiu; Sera, Dezso

2018-01-01

Enhanced quality images are necessary for EL image analysis and failure quantification. A method is proposed which determines image quality in terms of more accurate failure detection of solar panels through electroluminescence (EL) imaging technique. The goal of the paper is to determine the most...

Quantifying Solar Cell Cracks in Photovoltaic Modules by Electroluminescence Imaging

DEFF Research Database (Denmark)

Spataru, Sergiu; Hacke, Peter; Sera, Dezso

2015-01-01

This article proposes a method for quantifying the percentage of partially and totally disconnected solar cell cracks by analyzing electroluminescence images of the photovoltaic module taken under high- and low-current forward bias. The method is based on the analysis of the module’s electrolumin...

Electroluminescence and photosensitivity spectra of organic diode structures based on zinc complexes

International Nuclear Information System (INIS)

Kaplunov, M.G.; Krasnikova, S.S.; Nikitenko, S.L.; Yakushchenko, I.K.

2017-01-01

Devices based on zinc complexes with sulphanylaminosubstituted ligands are characterized by dual function – electroluminescence (EL) and photosensitivity. Both EL and photosensitivity are associated with the formation of exciplexes.

Tunable magneto-conductance and magneto-electroluminescence in polymer light-emitting electrochemical planar devices

Energy Technology Data Exchange (ETDEWEB)

Geng, R.; Mayhew, N. T.; Nguyen, T. D., E-mail: ngtho@uga.edu [Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602 (United States)

2013-12-09

We report studies of magneto-conductance (MC) and magneto-electroluminescence (MEL) in polymer light-emitting electrochemical planar devices using “super-yellow” poly-(phenylene vinylene). We observed consistent negative MC while MEL becomes positive when electroluminescence quantum efficiency (ELQE) increases. At an optimal ELQE, the MC has a much narrower width than the MEL, indicating that the MC and MEL do not share a common origin. However, MC reverses and has the same width as MEL when exposed to a threshold laser power. We show that the e-h pair model can explain the positive MEL and MC while the negative MC can be explained by the bipolaron model.

Tunable magneto-conductance and magneto-electroluminescence in polymer light-emitting electrochemical planar devices

International Nuclear Information System (INIS)

Geng, R.; Mayhew, N. T.; Nguyen, T. D.

2013-01-01

We report studies of magneto-conductance (MC) and magneto-electroluminescence (MEL) in polymer light-emitting electrochemical planar devices using “super-yellow” poly-(phenylene vinylene). We observed consistent negative MC while MEL becomes positive when electroluminescence quantum efficiency (ELQE) increases. At an optimal ELQE, the MC has a much narrower width than the MEL, indicating that the MC and MEL do not share a common origin. However, MC reverses and has the same width as MEL when exposed to a threshold laser power. We show that the e-h pair model can explain the positive MEL and MC while the negative MC can be explained by the bipolaron model

Palladium-based on-wafer electroluminescence studies of GaN-based LED structures

Energy Technology Data Exchange (ETDEWEB)

Salcianu, C.O.; Thrush, E.J.; Humphreys, C.J. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Plumb, R.G. [Centre for Photonic Systems, Department of Engineering, University of Cambridge, Cambridge CB3 0FD (United Kingdom); Boyd, A.R.; Rockenfeller, O.; Schmitz, D.; Heuken, M. [AIXTRON AG, Kackertstr. 15-17, 52072 Aachen (Germany)

2008-07-01

Electroluminescence (EL) testing of Light Emitting Diode (LED) structures is usually done at the chip level. Assessing the optical and electrical properties of LED structures at the wafer scale prior to their processing would improve the cost effectiveness of producing LED-lamps. A non-destructive method for studying the luminescence properties of the structure at the wafer-scale is photoluminescence (PL). However, the relationship between the on-wafer PL data and the final device EL can be less than straightforward (Y. H Aliyu et al., Meas. Sci. Technol. 8, 437 (1997)) as the two techniques employ different carrier injection mechanisms. This paper provides an overview of some different techniques in which palladium is used as a contact in order to obtain on-wafer electroluminescence information which could be used to screen wafers prior to processing into final devices. Quick mapping of the electrical and optical characteristics was performed using either palladium needle electrodes directly, or using the latter in conjunction with evaporated palladium contacts to inject both electrons and holes into the active region via the p-type capping layer of the structure. For comparison, indium was also used to make contact to the n-layer so that electrons could be directly injected into that layer. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Electroluminescence from porous silicon due to electron injection from solution

NARCIS (Netherlands)

Kooij, Ernst S.; Despo, R.W.; Kelly, J.J.

1995-01-01

We report on the electroluminescence from p‐type porous silicon due to minority carrier injection from an electrolyte solution. The MV+• radical cation formed in the reduction of divalent methylviologen is able to inject electrons into the conduction band of crystalline and porous silicon. The

Low temperature transient response and electroluminescence characteristics of OLEDs based on Alq{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Yuan, Chao [Key Laboratory of Semiconductor Material Sciences, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); College of Materials Science and Optoelectronic Devices, University of Chinese Academy of Sciences, Beijing 100049 (China); Guan, Min, E-mail: guanmin@semi.ac.cn [Key Laboratory of Semiconductor Material Sciences, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Zhang, Yang [Key Laboratory of Semiconductor Material Sciences, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); College of Materials Science and Optoelectronic Devices, University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Yiyang; Liu, Shuangjie [Key Laboratory of Semiconductor Material Sciences, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Zeng, Yiping [Key Laboratory of Semiconductor Material Sciences, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); College of Materials Science and Optoelectronic Devices, University of Chinese Academy of Sciences, Beijing 100049 (China)

2017-08-15

Highlights: • The dependency relation between transmission rate and electron transport layer is revealed. • The critical temperature points for the influence of luminescent materials and injection barriers on delay time are found. • The influence of light-emitting material and injection layer on carrier accumulation is quantified. - Abstract: In this work, the organic light-emitting diodes (OLEDs) based on Alq{sub 3} are fabricated. In order to make clear the transport mechanism of carriers in organic light-emitting devices at low temperature, detailed electroluminescence transient response and the current-voltage–luminescence (I–V–L) characteristics under different temperatures in those OLEDs are investigated. It founds that the acceleration of brightness increases with increasing temperature is maximum when the temperature is 200 K and it is mainly affected by the electron transport layer (Alq{sub 3}). The MoO{sub 3} injection layer and the electroluminescent layer have great influence on the delay time when the temperature is 200 K. Once the temperature is greater than 250 K, the delay time is mainly affected by the MoO{sub 3} injection layer. On the contrary, the fall time is mainly affected by the electroluminescent material. The V{sub f} is the average growth rate of fall time when the temperature increases 1 K which represents the accumulation rate of carriers. The difference between V{sub f} caused by the MoO{sub 3} injection layer is 0.52 us/K and caused by the electroluminescent material Ir(ppy){sub 3} is 0.73 us/K.

Shell model for REO{sub x} nanoclusters in amorphous SiO{sub 2}: charge trapping and electroluminescence quenching

Energy Technology Data Exchange (ETDEWEB)

Tiagulskyi, S.; Nazarov, A.; Tyagulskii, I.; Lysenko, V. [Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Prospekt Nauki 41, 03028 Kiev (Ukraine); Rebohle, L.; Lehmann, J.; Skorupa, W. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden Rossendorf e.V., POB 510119, 01314 Dresden (Germany)

2012-06-15

In this work charge trapping and electroluminescence (EL) quenching in rare-earth (RE) implanted SiO{sub 2} on Si as a function of injected charge into the dielectric were studied. The blocking of the luminescent REO{sub X} nanoclusters from the hot exciting electrons by negative charge trapping in a defect region (shell) located in the vicinity of the REO{sub X} nanocluster/SiO{sub 2} interface is considered as the main mechanism of EL quenching for small size (up to 10 nm) REO{sub X} nanoclusters. It is suggested that the increase of the nanoclusters size results in disordering of the SiO{sub 2} matrix but in a decrease of local blocking for excitation of the luminescent centers. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Electroluminescence Analysis by Tilt Polish Technique of InP-Based Semiconductor Lasers

Science.gov (United States)

Ichikawa, Hiroyuki; Sasaki, Kouichi; Hamada, Kotaro; Yamaguchi, Akira

2010-03-01

We developed an effective electroluminescence (EL) analysis method to specify the degraded region of InP-based semiconductor lasers. The EL analysis method is one of the most important methods for failure analysis. However, EL observation was difficult because opaque electrodes surround an active layer. A portion of each electrode had to be left intact for wiring to inject the current. Thus, we developed a partial polish technique for the bottom electrode. Tilt polish equipment with a rotating table was introduced; a flat polished surface and a sufficiently wide remaining portion of the bottom electrode were obtained. As a result, clear EL from the back surface of the laser was observed.

Bias-polarity-dependent UV/visible transferable electroluminescence from ZnO nanorod array LED with graphene oxide electrode supporting layer

Science.gov (United States)

Liu, Weizhen; Wang, Wei; Xu, Haiyang; Li, Xinghua; Yang, Liu; Ma, Jiangang; Liu, Yichun

2015-09-01

A simple top electrode preparation process, employing continuous graphene oxide films as electrode supporting layers, was adopted to fabricate a ZnO nanorod array/p-GaN heterojunction LED. The achieved LED demonstrated different electroluminescence behaviors under forward and reverse biases: a yellow-red emission band was observed under forward bias, whereas a blue-UV emission peak was obtained under reverse bias. Electroluminescence spectra under different currents and temperatures, as well as heterojunction energy-band alignments, reveal that the yellow-red emission under forward bias originates from recombinations related to heterointerface defects, whereas the blue-UV electroluminescence under reverse bias is ascribed to transitions from near-band-edge and Mg-acceptor levels in p-GaN.

Electroluminescent devices based on rare-earth tetrakis β-diketonate complexes

International Nuclear Information System (INIS)

Quirino, W.G.; Legnani, C.; Santos, R.M.B. dos; Teixeira, K.C.; Cremona, M.; Guedes, M.A.; Brito, H.F.

2008-01-01

In this paper the synthesis, photoluminescence and electroluminescence investigation of the novel tetrakis β-diketonate of rare-earth complexes such as, M[Eu(dbm) 4 ] and M[Tb(acac) 4 ] with a variety of cationic ligands, M = Li + , Na + and K + have been investigated. The emission spectra of the Eu 3+ and Tb 3+ complexes displayed characteristic narrow bands arising from intraconfigurational transitions of trivalent rare-earth ions and exhibited red color emission for the Eu 3+ ion ( 5 D 0 → 7 F J , J = 0-6) and green for the Tb 3+ ion ( 5 D 4 → 7 F J , J = 6-0). The lack of the broaden emission bands arising from the ligands suggests the efficient intramolecular energy transfer from the dbm and acac ligands to Eu 3+ and Tb 3+ ions, respectively. In accordance to the expected, the values of PL quantum efficiency (η) of the emitting 5 D 0 state of the tetrakis(β-diketonate) complexes of Eu 3+ were higher compared with those tris-complexes. Therefore, organic electroluminescent (EL) devices were fabricated with the structure as follows: indium tin oxide (ITO)/hole transport layer (HTL) NPB or MTCD/emitter layer M[RE(β-diketonate) 4 ] complexes)/Aluminum (Al). All the films were deposited by thermal evaporation carried out in a high vacuum environment system. The OLED light emission was independent of driving voltage, indicating that the combination of charge carriers generates excitons within the M[RE(β-diketonate) 4 ] layers, and the energy is efficiently transferred to RE 3+ ion. As a best result, a pure red and green electroluminescent emission was observed from the Eu 3+ and Tb 3+ devices, confirmed by (X,Y) color coordinates

Self-scaling minority carrier lifetime imaging using periodically modulated electroluminescence

Science.gov (United States)

Kropp, Timo; Berner, Marcel; Werner, Jürgen H.

2017-11-01

We present a straightforward self-scaling imaging technique to extract the effective minority carrier lifetime image of silicon solar cells using periodically modulated electroluminescence. This novel modulation technique overcomes main limiting factors linked to camera integration time. Our approach is based on comparing three luminescence images taken during current modulation. One image is taken while periodically injecting excess charge carriers with a pulsed current stimulation followed by an open-circuit luminescence decay. A second image with the same injection profile is taken while additionally extracting excess charge carriers at the falling edge, accelerating the luminescence decay. Both images are normalized to a steady-state image. The camera integration time is several orders of magnitude longer than the modulation period length, and no synchronization of image acquisition is needed. The intensity difference between both modulated images is used for determining a calibration factor to convert the steady-state image into the effective minority carrier lifetime image: Our modulation method enables carrier lifetime images completely independent of the image integration time. First carrier lifetime images show good agreement with data from time resolved electroluminescence.

Stable electroluminescence from passivated nano-crystalline porous silicon using undecylenic acid

Science.gov (United States)

Gelloz, B.; Sano, H.; Boukherroub, R.; Wayner, D. D. M.; Lockwood, D. J.; Koshida, N.

2005-06-01

Stabilization of electroluminescence from nanocrystalline porous silicon diodes has been achieved by replacing silicon-hydrogen bonds terminating the surface of nanocrystalline silicon with more stable silicon-carbon (Si-C) bonds. Hydrosilylation of the surface of partially and anodically oxidized porous silicon samples was thermally induced at about 90 °C using various different organic molecules. Devices whose surface have been modified with stable covalent bonds shows no degradation in the EL efficiency and EL output intensity under DC operation for several hours. The enhanced stability can be attributed to the high chemical resistance of Si-C bonds against current-induced surface oxidation associated with the generation of nonradiative defects. Although devices treated with 1-decene exhibit reduced EL efficiency and brightness compared to untreatred devices, other molecules, such as ethyl-undecylenate and particularly undecylenic acid provide stable and more efficient visible electroluminescence at room temperature. Undecylenic acid provides EL brightness as high as that of an untreated device.

Enhanced electroluminescence of organic light-emitting diodes by using halloysite nanotubes

Energy Technology Data Exchange (ETDEWEB)

Mondragón, Margarita, E-mail: mmondragon@ipn.mx [Instituto Politécnico Nacional, ESIME Azcapotzalco, Av. de las Granjas 682, 02250 México D.F. (Mexico); Moggio, Ivana; León, Arxel de; Arias, Eduardo [Centro de Investigación en Química Aplicada, CIQA, Blvd. Enrique Reyna 140, 25253 Saltillo, Coahuila (Mexico)

2013-12-15

The effect of halloysite clay nanotubes (HNTs) on the optical and electronic properties of poly(2-methoxy-5-[2′-ethylhexyloxy]-1,4-phenylenevinylene) (MEH-PPV) have been investigated. The UV–vis absorption band of the conjugated polymer remains unchanged upon the incorporation of halloysite nanotubes (HNTs). Photoluminescence (PL) measurements reveal a decreased quantum yield in the MEH-PPV/HNTs nanocomposites, compared with bulk MEH-PPV. Improvement of the electroluminescence of organic light-emitting diodes (OLEDs) was achieved by incorporating high contents of HNTs. The nanotubes act to enhanced polymer aggregates, as revealed by AFM analysis, thus increasing charge transport and therefore electroluminescence but also decreasing PL quantum yield. -- Highlights: • Thin films of nanocomposites of MEH-PPV/HNTs were prepared by spin coating. • Quantum yield in the nanocomposites was decreased compared with bulk MEH-PPV. • Improvement of the EL of OLEDs was achieved by incorporating high contents of HNTs. • The HNTs act to enhanced polymer aggregates, as revealed by AFM.

Enhanced electroluminescence of organic light-emitting diodes by using halloysite nanotubes

International Nuclear Information System (INIS)

Mondragón, Margarita; Moggio, Ivana; León, Arxel de; Arias, Eduardo

2013-01-01

The effect of halloysite clay nanotubes (HNTs) on the optical and electronic properties of poly(2-methoxy-5-[2′-ethylhexyloxy]-1,4-phenylenevinylene) (MEH-PPV) have been investigated. The UV–vis absorption band of the conjugated polymer remains unchanged upon the incorporation of halloysite nanotubes (HNTs). Photoluminescence (PL) measurements reveal a decreased quantum yield in the MEH-PPV/HNTs nanocomposites, compared with bulk MEH-PPV. Improvement of the electroluminescence of organic light-emitting diodes (OLEDs) was achieved by incorporating high contents of HNTs. The nanotubes act to enhanced polymer aggregates, as revealed by AFM analysis, thus increasing charge transport and therefore electroluminescence but also decreasing PL quantum yield. -- Highlights: • Thin films of nanocomposites of MEH-PPV/HNTs were prepared by spin coating. • Quantum yield in the nanocomposites was decreased compared with bulk MEH-PPV. • Improvement of the EL of OLEDs was achieved by incorporating high contents of HNTs. • The HNTs act to enhanced polymer aggregates, as revealed by AFM

Aftereffect of UV excitation on the ZnS electroluminescent emission

International Nuclear Information System (INIS)

Maxia, V.; Muntoni, C.; Murgia, M.

1980-01-01

The initial a.c. electroluminescent (EL) emission of ZnS(Cu) previously excited with UV light has been studied. The experiments showed that the EL build-up is made more swift by the preceding UV excitation. This result is ascribed to space charge produced by UV excitation which affects the exchange of electrons between lattice and EL defects. (author)

Electroluminescent efficiency of alternating current thick film devices using ZnS:Cu,Cl phosphor

International Nuclear Information System (INIS)

Sharma, Gaytri; Han, Sang Do; Kim, Jung Duk; Khatkar, Satyender P.; Rhee, Young Woo

2006-01-01

ZnS:Cu,Cl phosphor is prepared with the help of low intensity milling of the precursor material in two step firing process. The synthesized phosphor is used for the preparation of alternating current thick film electroluminescent (ACTFEL) devices with screen-printing method. The commission international de l'Eclairge (CIE) color co-ordinates of the ACTFEL devices prepared by these phosphor layers shows a shift from bluish-green to green region with the change in the amount of Cu in the phosphor. The various parameters to improve the efficiency and luminance of the devices have also been investigated. The brightness of the ac thick film EL device depends on the particle size of the phosphor, crystallinity, amount of binding material and applied voltage. The EL device fabricated with phosphor having average particle size of 25 μm shows maximum luminescence, when 60% phosphor concentration is used with respect to binding material. EL intensity is also linearly dependent on frequency. It is due the increase of excitation chances of the host matrix or dopant ions with increasing frequency

Electroluminescence and rectifying properties of heterojunction LEDs based on ZnO nanorods

International Nuclear Information System (INIS)

Rout, Chandra Sekhar; Rao, C N R

2008-01-01

n-ZnO NR/p-Si and n-ZnO NR/p-PEDOT/PSS heterojunction light-emitting diodes (LEDs) have been fabricated with ZnO nanorods (NRs) grown by a low-temperature method as well as by employing pulsed laser deposition (PLD). The low-temperature method involves growing the ZnO nanorods by the reaction of water with zinc metal. The current-voltage (I-V) characteristics of the heterojunctions show good rectifying diode characteristics. The electroluminescence (EL) spectra of the nanorods show an emission band at around 390 nm and defect related bands in the 400-550 nm region. Room-temperature electroluminescence is detected under forward bias for both the heterostructures. With the low-temperature grown nanorods, the defect related bands in the 400-550 nm range are more intense in the EL spectra, whereas with the PLD grown nanorods, only the 390 nm band is prominent

Quantitative Prediction of Power Loss for Damaged Photovoltaic Modules Using Electroluminescence

Directory of Open Access Journals (Sweden)

Timo Kropp

2018-05-01

Full Text Available Electroluminescence (EL is a powerful tool for the qualitative mapping of the electronic properties of solar modules, where electronic and electrical defects are easily detected. However, a direct quantitative prediction of electrical module performance purely based on electroluminescence images has yet to be accomplished. Our novel approach, called “EL power prediction of modules” (ELMO as presented here, used just two electroluminescence images to predict the electrical loss of mechanically damaged modules when compared to their original (data sheet power. First, using this method, two EL images taken at different excitation currents were converted into locally resolved (relative series resistance images. From the known, total applied voltage to the module, we were then able to calculate absolute series resistance values and the real distribution of voltages and currents. Then, we reconstructed the complete current/voltage curve of the damaged module. We experimentally validated and confirmed the simulation model via the characterization of a commercially available photovoltaic module containing 60 multicrystalline silicon cells, which were mechanically damaged by hail. Deviation between the directly measured and predicted current/voltage curve was less than 4.3% at the maximum power point. For multiple modules of the same type, the level of error dropped below 1% by calibrating the simulation. We approximated the ideality factor from a module with a known current/voltage curve and then expand the application to modules of the same type. In addition to yielding series resistance mapping, our new ELMO method was also capable of yielding parallel resistance mapping. We analyzed the electrical properties of a commercially available module, containing 72 monocrystalline high-efficiency back contact solar cells, which suffered from potential induced degradation. For this module, we predicted electrical performance with an accuracy of better

Electroluminescence and electrical degradation of insulating polymers at electrode interfaces under divergent fields

Science.gov (United States)

Zhang, Shuai; Li, Qi; Hu, Jun; Zhang, Bo; He, Jinliang

2018-04-01

Electrical degradation of insulating polymers at electrode interfaces is an essential factor in determining long-term reliability. A critical challenge is that the exact mechanism of degradation is not fully understood, either experimentally or theoretically, due to the inherent complex processes. Consequently, in this study, we investigate electroluminescence (EL) at the interface of an electrode and insulator, and determine the relationship between EL and electrical degradation. Using a tip-plate electrode structure, the unique features of EL under a highly divergent field are investigated. The voltage type (alternating or direct current), the polymer matrix, and the time of pressing are also investigated separately. A study of EL from insulators under a divergent field is provided, and the relationship between EL spectra and degradation is discussed. It is shown that EL spectra under a divergent field have unique characteristics compared with EL spectra from polymer films under a uniform field and the most obvious one is the UV emission. The results obtained in the current investigation bring us a step closer to understanding the process of electrical degradation and provide a potential way to diagnose insulator defects.

Stable electroluminescence from passivated nano-crystalline porous silicon using undecylenic acid

Energy Technology Data Exchange (ETDEWEB)

Gelloz, B.; Sano, H.; Koshida, N. [Dept. Elec. and Elec. Eng., Tokyo Univ. of A and T, Koganei, Tokyo 184-8588 (Japan); Boukherroub, R. [Laboratoire de Physique de la Matiere Condensee, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau (France); Wayner, D.D.M.; Lockwood, D.J. [National Research Council, Ottawa (Canada)

2005-06-01

Stabilization of electroluminescence from nanocrystalline porous silicon diodes has been achieved by replacing silicon-hydrogen bonds terminating the surface of nanocrystalline silicon with more stable silicon-carbon (Si-C) bonds. Hydrosilylation of the surface of partially and anodically oxidized porous silicon samples was thermally induced at about 90 C using various different organic molecules. Devices whose surface have been modified with stable covalent bonds shows no degradation in the EL efficiency and EL output intensity under DC operation for several hours. The enhanced stability can be attributed to the high chemical resistance of Si-C bonds against current-induced surface oxidation associated with the generation of nonradiative defects. Although devices treated with 1-decene exhibit reduced EL efficiency and brightness compared to untreated devices, other molecules, such as ethyl-undecylenate and particularly undecylenic acid provide stable and more efficient visible electroluminescence at room temperature. Undecylenic acid provides EL brightness as high as that of an untreated device. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Matrix metalloproteinase 2 (MMP-2) levels are increased in active acromegaly patients.

Science.gov (United States)

Karci, Alper Cagri; Canturk, Zeynep; Tarkun, Ilhan; Cetinarslan, Berrin

2017-07-01

During follow-up of acromegaly patients, there is a discordance rate of 30% between the measurements of growth hormone and insulin-like growth factor-1 levels. Further tests are required to determine disease activity in patients with discordant results. This study was planned to investigate an association of serum levels of matrix metalloproteinase-2, matrix metalloproteinase-9, and cathepsin B with disease activity in acromegaly patients. In this study, 64 acromegaly patients followed in our clinic were divided into two groups according to the 2010 consensus criteria for cure of acromegaly as patients with active disease (n = 24) and patients with controlled disease (n = 40). Serum matrix metalloproteinase-2, matrix metalloproteinase-9, and cathepsin B levels were measured by the enzyme-linked immunosorbent assay method. The mean serum matrix metalloproteinase-2 level was significantly higher in the active acromegaly patients than in the controlled acromegaly patients (150.1 ± 54.5 ng/mL vs. 100.2 ± 44.6 ng/mL; p matrix metalloproteinase-9 and cathepsin B levels (p = 0.205 and p = 0.598, respectively). Serum matrix metalloproteinase-2 levels of 118.3 ng/mL and higher had a sensitivity of 75% and a specificity of 77.5% in determining active disease. The risk of active acromegaly was 3.3 fold higher in the patients with a matrix metalloproteinase-2 level of >118.3 ng/mL than in the patients with a matrix metalloproteinase-2 level of matrix metalloproteinase-2 level is increased in the active acromegaly patients and a threshold value in determining active disease was defined for serum matrix metalloproteinase-2 level. This study is the first to compare acromegaly patients having active or controlled disease in terms of matrix metalloproteinase-2 and matrix metalloproteinase-9 levels. The results need to be confirmed by a study that will be conducted in a larger patient group also including a healthy control group to demonstrate the

Electroluminescent drift chamber with 16 μm spatial resolution

International Nuclear Information System (INIS)

Baskakov, V.I.; Dolgoshein, V.A.; Lebedenko, V.N.

1978-01-01

Studied are the characteristics of the dft electroluminscent chamber of an original design. For insuring high spatial resolution, the chamber has been filled with xenon to a pressure of 20 atm, which substantially decreases the electron diffusion during drift. Located at the end of the drift gap is an anode wire, 50 μm in dia. A strong electric field available near the thin wire causes electroluminescence of the electrons. The signal is localized within a small volume and contribution of the luminescence time in the total duration of a signal is small. In this case no electron multiplication occurs at all and, consequently, no space charge of positive ions takes place, which makes it possible to operate at very high loadings (2x10 6 particle/s). The characteristics of the chamber are measured in a beam of the Serpukhov accelerator. Use has been made of a model comprising two chambers, 5 mm thick, located successively along the beam with the effective area being 40x40 mm. The studies and analysis performed reveal that the drift electroluminescent chamber operates reliably in the wide range of the working gas pressure at an intensity of the incident particles up to 10 5 particle/s. The best resolution is obtained at a pressure of 20 atm and it equals 16 μm

[Multiple emissions in organic electroluminescent device using a mixed layer as an emitter].

Science.gov (United States)

Zhu, Wen-qing; Wu, You-zhi; Zheng, Xin-you; Jiang, Xue-yin; Zhang, Zhi-lin; Sun, Run-guang; Xu, Shao-hong

2005-04-01

A organic electroluminescent device has been fabricated by using a mixed layer as an emitter. The configuration of the device is ITO/TPD/TPD: PBD(equimole)/PBD/A1, in which TPD (N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine) and PBD (2-(4'-biphenyl)-5-(4''-tert-butylphenyl)-1,3,4-oxadiazole) are used as hole transport material and electron transport material, respectively. Broad and red-shifted electroluminescent spectra related to the fluorescence of constituent materials were observed. It is suggested that the monomer, exciplex and electroplex emissions are simultaneously involved in EL spectra by comparison of the EL with the PL spectra and decomposition of the EL spectrum. The type of exciplex is the interaction between the excited state TPD (TPD*) and PBD in the ground state, and the type of electroplex is a (D+-A-)* complex by cross-recombination of hole on the charged hole transport molecule (D+) and electron on the charged electron transport molecule (A-). All types of excited states show different formation mechanisms and recombination processes under electric field. The change of emission strengths from monomer and excited complexes lead to a blue-shift of the emissive spectra with an increasing electric field. The maximum luminance and external quantum efficiency of this device are 240 cd x (cm2)(-1) and 0.49%, respectively. The emissions from exciplex or electroplex formation at the organic solid interface generally present a broad and red-shifted emissive band, providing an effective method for tuning of emission color in organic electroluminescent devices.

Two-phase xenon detector with gas amplification and electroluminescent signal detection

International Nuclear Information System (INIS)

Akimov, D.Yu.; Burenkov, A.A.; Grishkin, Yu.L.; Kovalenko, A.G.; Lebedenko, V.N.; Stekhanov, V.N.

2008-01-01

An optical technique for detecting ionization electrons produced during ionization of the liquid phase has been experimentally tested in two-phase (liquid-gas) xenon. The effects of gas and electroluminescent amplifications at the wire anode are simultaneously used for detection. This method allows construction of a supersensitive detector of small ionization signals-down to those corresponding to the detection of single electrons [ru

Synthesis and electroluminescent properties of blue emitting materials based on arylamine-substituted diphenylvinylbiphenyl derivatives for organic light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Lee, Kum Hee; You, Jae Nam; Won, Jiyeon; Lee, Jin Yong [Department of Chemistry, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Seo, Ji Hoon [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of); Kim, Young Kwan, E-mail: kimyk@hongik.ac.kr [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of); Yoon, Seung Soo, E-mail: ssyoon@skku.edu [Department of Chemistry, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of)

2011-10-31

This paper reports the synthesis and electroluminescent properties of a series of blue emitting materials with arylamine and diphenylvinylbiphenyl groups for applications to efficient blue organic light-emitting diodes (OLEDs). All devices exhibited blue electroluminescence with electroluminescent properties that were quite sensitive to the structural features of the dopants in the emitting layers. In particular, the device using dopant 4 exhibited sky-blue emission with a maximum luminance, luminance efficiency, power efficiency, external quantum efficiency and CIE coordinates of 39,000 cd/m{sup 2}, 12.3 cd/A, 7.45 lm/W, 7.71% at 20 mA/cm{sup 2} and (x = 0.17, y = 0.31) at 8 V, respectively. In addition, a blue OLED using dopant 2 with CIE coordinates (x = 0.16, y = 0.18) at 8 V exhibited a luminous efficiency, power efficiency and external quantum efficiency of 4.39 cd/A, 2.46 lm/W and 2.97% at 20 mA/cm{sup 2}, respectively.

Enhancing light emission in flexible AC electroluminescent devices by tetrapod-like zinc oxide whiskers.

Science.gov (United States)

Wen, Li; Liu, Nishuang; Wang, Siliang; Zhang, Hui; Zhao, Wanqiu; Yang, Zhichun; Wang, Yumei; Su, Jun; Li, Luying; Long, Fei; Zou, Zhengguang; Gao, Yihua

2016-10-03

Flexible alternating current electroluminescent devices (ACEL) are more and more popular and widely used in liquid-crystal display back-lighting, large-scale architectural and decorative lighting due to their uniform light emission, low power consumption and high resolution. However, presently how to acquire high brightness under a certain voltage are confronted with challenges. Here, we demonstrate an electroluminescence (EL) enhancing strategy that tetrapod-like ZnO whiskers (T-ZnOw) are added into the bottom electrode of carbon nanotubes (CNTs) instead of phosphor layer in flexible ACEL devices emitting blue, green and orange lights, and the brightness is greatly enhanced due to the coupling between the T-ZnOw and ZnS phosphor dispersed in the flexible polydimethylsiloxane (PDMS) layer. This strategy provides a new routine for the development of high performance, flexible and large-area ACEL devices.

High-Color-Quality White Top-Emitting Organic Electroluminescent Devices Based on Both Exciton and Electroplex Emission

Science.gov (United States)

Zhang, Mingxiao; Chen, Zhijian; Xiao, Lixin; Qu, Bo; Gong, Qihuang

2011-08-01

A high-color-quality white top-emitting organic electroluminescent device (TOLED) with a simple structure was fabricated using both exciton and electroplex emission. White emission was achieved by combining the exciton emission of 4,4'-bis(2,2'-diphenylvinyl)-1,1'-biphenyl (DPVBi) and the broad band emission of electroplex generated between DPVBi and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP). The white emission spectra showed excellent stability at different bias voltages. By inserting a blend film of DPVBi:BCP and adjusting the ratio of DPVBi to BCP in the blend film, the CIE coordinates of the white emission can be tuned to (0.30, 0.33) and the electroluminescence efficiency can also be enhanced.

Fiscal 1999 achievement report on regional consortium research and development project. Regional consortium activity in its 3rd year (Research and development of technologies for creating novel organic electroluminescent devices); 1999 nendo shin'yuki electroluminescence device no sosei gijutsu ni kansuru kenkyu kaihatsu seika hokokusho. 3

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

Development is reported of an autoluminescent planar display and a free shape novel light source based on the technology of creating organic electroluminescent (EL) devices. A small dose of desiccant is added to an inorganic amorphous protecting film, and then high reliability is attained with the film staying in service for 30,000 hours or more. Technologies of ensuring uniform luminescence on a 100 times 100mm large screen and forming a 0.2mm pitch electrode pattern are established, and a 320 times 240 dot simple matrix display is developed. Novel red luminescent materials are developed, which are luminescent materials which incorporate Eu ions as luminescent seeds and exhibit a sharp luminescent spectrum, and novel organic materials. Novel blue luminescent materials are also developed. As for white luminescent materials, two types of novel pigments are developed. Studies are under way to apply amphoteric carrier transport materials to EL devices. A novel sealing technology is established which uses a composite material made of fine glass powder and UV setting resin. A SiON-based protecting film is successfully fabricated by which the internal stress is minimized. A technology is established of fabricating a diamond-like carbon (DLC) film for the protection of electrodes and wiring circuits. (NEDO)

Fiscal 1999 achievement report on regional consortium research and development project. Regional consortium activity in its 3rd year (Research and development of technologies for creating novel organic electroluminescent devices); 1999 nendo shin'yuki electroluminescence device no sosei gijutsu ni kansuru kenkyu kaihatsu seika hokokusho. 3

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

Development is reported of an autoluminescent planar display and a free shape novel light source based on the technology of creating organic electroluminescent (EL) devices. A small dose of desiccant is added to an inorganic amorphous protecting film, and then high reliability is attained with the film staying in service for 30,000 hours or more. Technologies of ensuring uniform luminescence on a 100 times 100mm large screen and forming a 0.2mm pitch electrode pattern are established, and a 320 times 240 dot simple matrix display is developed. Novel red luminescent materials are developed, which are luminescent materials which incorporate Eu ions as luminescent seeds and exhibit a sharp luminescent spectrum, and novel organic materials. Novel blue luminescent materials are also developed. As for white luminescent materials, two types of novel pigments are developed. Studies are under way to apply amphoteric carrier transport materials to EL devices. A novel sealing technology is established which uses a composite material made of fine glass powder and UV setting resin. A SiON-based protecting film is successfully fabricated by which the internal stress is minimized. A technology is established of fabricating a diamond-like carbon (DLC) film for the protection of electrodes and wiring circuits. (NEDO)

Investigation of thioglycerol stabilized ZnS quantum dots in electroluminescent device performance

Science.gov (United States)

Ethiraj, Anita Sagadevan; Rhen, Dani; Lee, D. H.; Kang, Dae Joon; Kulkarni, S. K.

2016-05-01

The present work is focused on the investigation of thioglycerol (TG) stabilized Zinc Sulfide Quantum dots (ZnS QDs) in the hybrid electroluminescence (EL) device. Optical absorption spectroscopy clearly indicates the formation of narrow size distributed ZnS in the quantum confinement regime. X-ray Diffraction (XRD), Photoluminescence (PL), Energy Dispersive X-ray Spectroscopy (EDS) data supports the same. The hybrid EL device with structure of ITO (indium tin oxide)//PEDOT:PSS ((poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate)//HTL (α NPD- N,N'-diphenyl-N,N'-bis(1-naphthyl)-(1,1'-phenyl)-4,4'-diamine// PVK:ZnS QDs//ETL(PBD- 2-tert-butylphenyl- 5-biphenyl-1,3,4-oxadiazole)//LiF:Al (Device 1) was fabricated. Reference device without the ZnS QDs were also prepared (Device 2). The results show that the ZnS QDs based device exhibited bright electroluminescence emission of 24 cd/m2 at a driving voltage of 16 Volts under the forward bias conditions as compared to the reference device without the ZnS QDs, which showed 6 cd/m2 at ˜22 Volts.

pH-Sensitive Microparticles with Matrix-Dispersed Active Agent

Science.gov (United States)

Li, Wenyan (Inventor); Buhrow, Jerry W. (Inventor); Jolley, Scott T. (Inventor); Calle, Luz M. (Inventor)

2014-01-01

Methods to produce pH-sensitive microparticles that have an active agent dispersed in a polymer matrix have certain advantages over microcapsules with an active agent encapsulated in an interior compartment/core inside of a polymer wall. The current invention relates to pH-sensitive microparticles that have a corrosion-detecting or corrosion-inhibiting active agent or active agents dispersed within a polymer matrix of the microparticles. The pH-sensitive microparticles can be used in various coating compositions on metal objects for corrosion detecting and/or inhibiting.

Electroluminescence property improvement by adjusting quantum wells’ position relative to p-doped region in InGaN/GaN multiple-quantum-well light emitting diodes

Directory of Open Access Journals (Sweden)

P. Chen

2017-03-01

Full Text Available The hole distribution and electroluminescence property improvement by adjusting the relative position between quantum wells and p-doped region in InGaN/GaN multiple-quantum-well structures are experimentally and theoretically investigated. Five designed samples with different barrier layer parameters of multiple-quantum-well structure are grown by MOCVD and then fabricated into devices. The electroluminescence properties of these samples are measured and compared. It is found that the output electroluminescence intensity of samples is enhanced if the position of quantum wells shifts towards p-side, while the output power is reduced if their position is shifted towards the n-side. The theoretical calculation of characteristics of these devices using the simulation program APSYS agrees well with the experimental data, illustrating that the effect of relative position between p-doped region and quantum wells on the improvement of hole distribution and electroluminescence performance is significant, especially for InGaN/GaN multiple-quantum-well devices operated under high injection condition.

The surface defect-related electroluminescence from the ZnO microwire

Energy Technology Data Exchange (ETDEWEB)

Ding Meng; Zhao Dongxu; Yao Bin; Li Binghui; Zhang Zhenzhong; Shan Chongxin; Shen Dezhen, E-mail: dxzhao2000@yahoo.com.cn [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130021 (China)

2011-02-23

Surface defect-related electroluminescence (EL) was realized from a single ZnO microwire-based metal-semiconductor-metal structure on a glass substrate. ZnO microwires were successfully fabricated using a simple chemical vapour deposition approach. Schottky contacts were detected between Au electrodes and the ZnO microwire. The EL spectrum showed a broad emission band covering the visible range from 400 to 700 nm. The possible EL emission mechanism is discussed in detail in this paper.

Calcium-Oxidant Signaling Network Regulates AMP-activated Protein Kinase (AMPK) Activation upon Matrix Deprivation*

Science.gov (United States)

Sundararaman, Ananthalakshmy; Amirtham, Usha; Rangarajan, Annapoorni

2016-01-01

The AMP-activated protein kinase (AMPK) has recently been implicated in anoikis resistance. However, the molecular mechanisms that activate AMPK upon matrix detachment remain unexplored. In this study, we show that AMPK activation is a rapid and sustained phenomenon upon matrix deprivation, whereas re-attachment to the matrix leads to its dephosphorylation and inactivation. Because matrix detachment leads to loss of integrin signaling, we investigated whether integrin signaling negatively regulates AMPK activation. However, modulation of focal adhesion kinase or Src, the major downstream components of integrin signaling, failed to cause a corresponding change in AMPK signaling. Further investigations revealed that the upstream AMPK kinases liver kinase B1 (LKB1) and Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ) contribute to AMPK activation upon detachment. In LKB1-deficient cells, we found AMPK activation to be predominantly dependent on CaMKKβ. We observed no change in ATP levels under detached conditions at early time points suggesting that rapid AMPK activation upon detachment was not triggered by energy stress. We demonstrate that matrix deprivation leads to a spike in intracellular calcium as well as oxidant signaling, and both these intracellular messengers contribute to rapid AMPK activation upon detachment. We further show that endoplasmic reticulum calcium release-induced store-operated calcium entry contributes to intracellular calcium increase, leading to reactive oxygen species production, and AMPK activation. We additionally show that the LKB1/CaMKK-AMPK axis and intracellular calcium levels play a critical role in anchorage-independent cancer sphere formation. Thus, the Ca2+/reactive oxygen species-triggered LKB1/CaMKK-AMPK signaling cascade may provide a quick, adaptable switch to promote survival of metastasizing cancer cells. PMID:27226623

Characterization of UV-enhanced SiPMs for Imaging in High Pressure Xenon Electroluminescent TPC

International Nuclear Information System (INIS)

Yahlali, Nadia; Lorca, David; Fernandes, L.M.P.

2013-06-01

The possibility of recording charged particle tracks in an electro-luminescent xenon gas TPC is investigated using a SiPM-based tracking system, operated in the demonstrator prototype of the NEXT-100 ββ decay experiment. The tracks of the ββ0ν events from the decay of the 136 Xe isotope have a distinctive topology, which allows their discrimination against single-electron events from the natural radioactivity that populates the region of interest of the neutrinoless decay in the ββ energy spectrum. Combined to the near-intrinsic energy resolution of the gaseous detector, this tracking capability provides a powerful background rejection tool for the search of the neutrinoless ββ decay aimed by the experiment. The NEXT-100 detector concepts and sensitivity and the first results of its demonstrator prototype are presented. The characterization studies relevant for the operation of UV-enhanced SiPMs used for imaging in an electro-luminescent TPC are reviewed. (authors)

Photoluminescence and electroluminescence of a tripodal compound containing 7-diethylamino-coumarin moiety

Energy Technology Data Exchange (ETDEWEB)

Yu Tianzhi; Zhang Peng; Zhang Hui; Meng Jing; Fan Duowang [Key Laboratory of Opto-Electronic Technology and Intelligent Control (Lanzhou Jiaotong University), Ministry of Education, Lanzhou 730070 (China); Zhao Yuling; Dong Wenkui [School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070 (China)], E-mail: ytz823@hotmail.com

2008-12-07

A novel tripodal compound, tris[2-(7-diethylamino-coumarin-3-carboxamide)ethyl]amine (Tren-C), was synthesized and characterized by elemental analysis, infrared and {sup 1}H-NMR spectra. The photoluminescent (PL) and electroluminescent properties of Tren-C were investigated. Tren-C exhibits different colour emissions in solid states and solutions. The electroluminescence devices comprising vacuum vapour-deposited films using the compound as a dopant were fabricated, showing blue emissions that are identical to its PL spectrum in chloroform solutions. With the device structure of indium tin oxide (ITO)/4, 4', 4''-tris-N-naphthyl-N-phenylamino-triphenylamine (2-TNATA) (5 nm)/N, N'-bis-(naphthyl)-N, N'-diphenyl-1, 1'-biphenyl-4, 4'-diamine (NPB) (40 nm)/4, 4'-bis(9-carbazolyl) biphenyl (CBP) : Tren-C (0.5 wt%, 30 nm)/2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1, 3, 4-oxadiazole (Bu-PBD) (30 nm)/LiF (1 nm)/Al (100 nm), a maximum external quantum efficiency of 2.85%, a maximum luminous efficiency of 3.85 cd A{sup -1} and a maximum luminance of 1450 cd m{sup -2} are realized.

[The role of BCP in electroluminescence of multilayer organic light-emitting devices].

Science.gov (United States)

Deng, Zhao-Ru; Yang, Sheng-Yi; Lou, Zhi-Dong; Meng, Ling-Chuan

2009-03-01

As a hole-blocking layer, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) is usually used in blue and white light electroluminescent devices. The ability of blocking holes of BCP layer depends on its thickness, and basically holes can tunnel through thin BCP layer. In order to know the role of BCP layer in electroluminescence (EL) of multilayer organic light-emitting diodes (OLEDs), in the present paper, the authors designed a multilayer OLED ITO/NPB/BCP/Alq3 : DCJTB/Alq3/Al and investigated the influence of thickness of BCP on the EL spectra of multilayer OLEDs at different applied voltages. The experimental data show that thin BCP layer can block holes partially and tune the energy transfer between different emissive layers, and in this way, it is easy to obtain white emission, but its EL spectra will change with the applied voltages. The EL spectra of multilayer device will remain relatively stable when BCP layer is thick enough, and the holes can hardly tunnel through when the thickness of BCP layer is more than 15 nm. Furthermore, the stability of EL spectra of the multilayer OLED at different applied voltages was discussed.

Structural, morphological and electroluminescence studies of Zno:Co nanophosphor

Science.gov (United States)

Singh, Anju; Vishwakarma, H. L.

2016-09-01

The nanoparticles of zinc oxide (ZnO) doped with various concentrations of cobalt (Co) were synthesized by chemical precipitation method in the presence of capping agent polyvinylpyrrolidone (PVP). The effect of doping concentration on structural and morphological properties has been studied by X-ray diffraction (XRD) and scanning electron microscope (SEM). Cell volume, bond length, texture coefficient, lattice constants and dislocation density are also studied. Here, we also compared the interplaner spacing and relative peak intensities from their standard values with different angles. Crystallite sizes have been calculated by Debye-Scherrer's formula whose values are decreasing with increase in cobalt content up to 3 %. It has been seen that the growth orientation of the prepared ZnO nanorods was (101). The XRD analysis also ensures that ZnO has a hexagonal (wurtzite) crystal structure. The electroluminescence (EL) cells were prepared by placing pure and cobalt-doped ZnO nanoparticles between ITO-coated conducting glass plate and aluminium foil. Alternating voltage of various frequencies was applied, and EL brightness at different voltages was measured and corresponding current was also recorded. The voltage dependence of electroluminescence (EL) brightness of the ZnO:Co shows exponential increase. The linear voltage-current characteristic indicates ohmic nature. The EL brightness at a particular voltage is found to increase by increasing Co doping, but for higher percentage of Co the EL brightness is reduced. It is also seen that Co does not influence the threshold voltage. The brightness is also affected by increasing the frequency of AC signal.

Temperature dependence of electroluminescent emission from (ZnS : Cu, Mn(H)) type luminophors

International Nuclear Information System (INIS)

Singh, L.K.

1986-04-01

The dependence of electroluminescent yield on temperature for hydrogen coactivated (ZnS : Cu, Mn) type triple band emitting phosphors has been investigated at various temperatures under varied operating conditions of excitations. The influence of the excitation frequency, voltage and of emission wavelengths for the electroluminescent characteristics has also been observed on temperature variations. The results have also been studied for temperature dependences of emitting brightness under the excitation by UV-radiations of 3650 A.U. and a comparison is made between temperature dependent characteristics of E.L. and PL-brightness of emissions. It was observed that, as usual, brightness maxima on temperature scale varied with alteration of operating electric fields regarding frequency and voltage both for blue, green and yellow orange emissions of attempted samples. The important thing which is observed here, is that with regards the temperature EL-intensities vary respectively for all respective emissions but emission peaks are not shifted on wave-length scale. This no shift is due to the narrowly and compactly distributed coactivator levels of hydrogen. (author)

Moisture exposure to different layers in organic light-emitting diodes and the effect on electroluminescence characteristics

International Nuclear Information System (INIS)

Liao, L. S.; Tang, C. W.

2008-01-01

Moisture effect on electroluminescence characteristics, including current density versus voltage, luminance versus voltage, luminous efficiency versus current density, dark spot formation, and operational stability of organic light-emitting diodes, has been systematically investigated by exposing each layer of the devices to moisture at room temperature. Moisture has a different effect on each of the interfaces or surfaces, and the influence increases as exposure time increases. There is a slight effect on the electroluminescence characteristics after the anode surface has been exposed to moisture. However, severe luminance decrease, dark spot formation, and operational stability degradation take place after the light-emitting layer or the electron-transporting layer is exposed to moisture. It is also demonstrated that the effect of moisture can be substantially reduced if the exposure to moisture is in a dark environment

Unusual near-white electroluminescence of light emitting diodes based on saddle-shaped porphyrins.

Science.gov (United States)

Shahroosvand, Hashem; Zakavi, Saeed; Sousaraei, Ahmad; Mohajerani, Ezeddin; Mahmoudi, Malek

2015-05-14

In contrast to the red electroluminescence emission frequently observed in porphyrins based OLED devices, the present devices exhibit a nearly white emission with greenish yellow, yellowish green and blue green hues in the case of Fe(II)(TCPPBr6) (TCPPBr6 = β-hexabromo-meso-tetrakis-(4-phenyl carboxyl) porphyrinato), Zn(II)(TPPBr6) and Co(II)(TPPBr6), respectively.

Exciton-dominant Electroluminescence from a Diode of Monolayer MoS2

Science.gov (United States)

2014-05-14

injected electrons and holes, is a reliable technique to study exciton recombination processes in monolayer MoS2, including val- ley and spin excitation...temperature. After superimposing a white light scattering image of the de - vice, we find that the electroluminescence is localized at the edge of the...We find the emerged feature (labeled NX) peaks at 550 nm with energy of 2.255 eV. In low dimensional system, like monolayer MoS2, Coulomb interactions

Molding resonant energy transfer by colloidal crystal: Dexter transfer and electroluminescence

Science.gov (United States)

González-Urbina, Luis; Kolaric, Branko; Libaers, Wim; Clays, Koen

2010-05-01

Building photonic crystals by combination of colloidal ordering and metal sputtering we were able to construct a system sensitive to an electrical field. In corresponding crystals we embedded the Dexter pair (Ir(ppy3) and BAlq) and investigated the influence of the band gap on the resonant energy transfer when the system is excited by light and by an electric field respectively. Our investigations extend applications of photonic crystals into the field of electroluminescence and LED technologies.

Effect of resonant tunneling on electroluminescence in nc-Si/SiO2 multilayers-based p-i-n structure

International Nuclear Information System (INIS)

Chen, D.Y.; Wang, Y.Y.; Sun, Y.; He, Y.J.; Zhang, G.

2015-01-01

P-i-n structures with SiO 2 /nc-Si/SiO 2 multilayers as intrinsic layer were prepared in conventional plasma enhanced chemical vapor deposition system. Their carrier transport and electroluminescence properties were investigated. Two resonant tunneling related current peaks with current dropping gradually under forward bias were observed in the current voltage curve. Non-uniformity of the interfaces might be responsible for the gradual dropping of the current. Electroluminescence intensity of the device under bias of 7 V which is near the resonant tunneling peak voltage of 7.2 V was weaker than that under 6.5 V. According to the Gaussian fitting results of the spectra, the intensity of the sub-peak of 650 nm originating from recombination of injected electrons and holes was decreased the most. When resonant tunneling conditions are met, it might be that most of the injected electrons participate in resonant tunneling and fewer in Pool–Frenkel tunneling, which is the main carrier transport mechanism, to contribute to electroluminescence intensity. - Highlights: • Two resonant tunneling peaks with current dropping gradually were observed. • The EL intensity of the structure under resonant tunneling peak voltage is weakened. • P–F tunneling is the main transport mechanism besides resonant tunneling

Electroluminescence from single nanowires by tunnel injection: an experimental study

International Nuclear Information System (INIS)

Zimmler, Mariano A; Bao Jiming; Shalish, Ilan; Yi, Wei; Yoon, Joonah; Narayanamurti, Venkatesh; Capasso, Federico

2007-01-01

We present a hybrid light-emitting diode structure composed of an n-type gallium nitride nanowire on a p-type silicon substrate in which current is injected along the length of the nanowire. The device emits ultraviolet light under both bias polarities. Tunnel injection of holes from the p-type substrate (under forward bias) and from the metal (under reverse bias) through thin native oxide barriers consistently explains the observed electroluminescence behaviour. This work shows that the standard p-n junction model is generally not applicable to this kind of device structure

Electroluminescence Caused by the Transport of Interacting Electrons through Parallel Quantum Dots in a Photon Cavity

Science.gov (United States)

Gudmundsson, Vidar; Abdulla, Nzar Rauf; Sitek, Anna; Goan, Hsi-Sheng; Tang, Chi-Shung; Manolescu, Andrei

2018-02-01

We show that a Rabi-splitting of the states of strongly interacting electrons in parallel quantum dots embedded in a short quantum wire placed in a photon cavity can be produced by either the para- or the dia-magnetic electron-photon interactions when the geometry of the system is properly accounted for and the photon field is tuned close to a resonance with the electron system. We use these two resonances to explore the electroluminescence caused by the transport of electrons through the one- and two-electron ground states of the system and their corresponding conventional and vacuum electroluminescense as the central system is opened up by coupling it to external leads acting as electron reservoirs. Our analysis indicates that high-order electron-photon processes are necessary to adequately construct the cavity-photon dressed electron states needed to describe both types of electroluminescence.

Transient electroluminescence on pristine and degraded phosphorescent blue OLEDs

Science.gov (United States)

Niu, Quan; Blom, Paul W. M.; May, Falk; Heimel, Paul; Zhang, Minlu; Eickhoff, Christian; Heinemeyer, Ute; Lennartz, Christian; Crǎciun, N. Irina

2017-11-01

In state-of-the-art blue phosphorescent organic light-emitting diode (PHOLED) device architectures, electrons and holes are injected into the emissive layer, where they are carried by the emitting and hole transporting units, respectively. Using transient electroluminescence measurements, we disentangle the contribution of the electrons and holes on the transport and efficiency of both pristine and degraded PHOLEDs. By varying the concentration of hole transporting units, we show that for pristine PHOLEDs, the transport is electron dominated. Furthermore, degradation of the PHOLEDs upon electrical aging is not related to the hole transport but is governed by a decrease in the electron transport due to the formation of electron traps.

Near-infrared electroluminescence from double-emission-layers devices based on Ytterbium (III) complexes

International Nuclear Information System (INIS)

Li Zhefeng; Zhang Hongjie; Yu Jiangbo

2012-01-01

We investigated near-infrared electroluminescence properties of two lanthanide complexes Yb(PMBP) 3 Bath [PMBP = tris(1-phenyl-3-methyl-4-(4-tert-butylbenzacyl)-5-pyrazolone); Bath = bathophenanthroline] and Yb(PMIP) 3 TP 2 [PMIP = tris(1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone); TP = triphenyl phosphine oxide] by fabricated the double-emission-layers devices. From the device characteristics, it is known that holes are easier to transport in Yb(PMIP) 3 TP 2 layer and electrons are easier to transport in Yb(PMBP) 3 Bath layer, at the same time, both of the two complexes can be acted as emission layers in the device. The recombination region of carriers has been confined in the interface of Yb(PMIP) 3 TP 2 /Yb(PMBP) 3 Bath, and pure Yb 3+ ion characteristic emission centered at 980 nm has been obtained. The device shows the maximum near-infrared irradiance as 14.7 mW/m 2 at the applied voltage of 17.8 V. - Highlights: ► Near-infrared electroluminescent devices with Yb(III) complexes as emission layers. ► Double-emission layer device structure introduced to balance carriers. ► Improved performance of double-emission layer device.

Thin film electroluminescent cells on the basis of Ce-doped CaGa2S4 and SrGa2S4 prepared by flash evaporation method

International Nuclear Information System (INIS)

Gambarov, E.; Bayramov, A.; Kato, A.; Iida, S.

2006-01-01

Ce-doped CaGa 2 S 4 and SrGa 2 S 4 thin film electroluminescent (TFEL) devices were prepared for the first time on the basis of films deposited by flash evaporation method. Significant crystallization, stoichiometry improvement of the films and increase of photoluminescence intensity were found after annealing in H 2 S and O 2 gas stream. EL spectra of the cells exhibited the characteristic double-band emission similar to that seen for Ce 3+ activated CaGa 2 S 4 and SrGa 2 S 4 films under photon excitation. Applied voltage and frequency dependences of the electroluminescence were studied. Low voltage operation as low as 20 V was observed for these cells. Luminance of about 4 cd/m 2 at 100 V operating voltage with 2.5 kHz frequency was achieved for the TFEL cell with films annealed in O 2 gas stream. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Electroluminescence properties of organic light-emitting diodes with a red dye doped into Alq{sub 3} : rubrene mixed host

Energy Technology Data Exchange (ETDEWEB)

Kang, H. Y. [Inha University, Incheon (Korea, Republic of); Lee, C. H. [Seoul National University, Seoul (Korea, Republic of)

2004-09-15

We have studied the electroluminescence (EL) properties of devices with a red fluorescent dye, 4-(dicyanomethylene)-2-t-butyl-6- (1,1,7,7-tetramethyl-julolidyl-9-enyl)--4H-py ran (DCJTB), doped into a mixed matrix of tris-(8-hydroxyquinoline)aluminum (Alq{sub 3}) and rubrene. The devices doped with DCJTB in the Alq{sub 3}:rubrene mixed host show an efficient red emission from DCJTB with negligible EL emission from both Alq{sub 3} and rubrene. The QE increases with increasing rubrene concentration and reaches a maximum of about 3.6 % for a DCJTB doping concentration of about 5 % in the Alq3:rubrene mixed (50:50 % ratio by weight) host, and then decreases at higher rubrene concentration, due to the concentration quenching effect. At a given bias voltage, the current density increases with increasing rubrene doping concentration, but it decreases with increasing DCJTB doping concentration. The results imply that the injected electrons and holes can transport via hopping through the energy levels of rubrene molecules while DCJTB acts as traps.

Google matrix of the world network of economic activities

Science.gov (United States)

Kandiah, Vivek; Escaith, Hubert; Shepelyansky, Dima L.

2015-07-01

Using the new data from the OECD-WTO world network of economic activities we construct the Google matrix G of this directed network and perform its detailed analysis. The network contains 58 countries and 37 activity sectors for years 1995 and 2008. The construction of G, based on Markov chain transitions, treats all countries on equal democratic grounds while the contribution of activity sectors is proportional to their exchange monetary volume. The Google matrix analysis allows to obtain reliable ranking of countries and activity sectors and to determine the sensitivity of CheiRank-PageRank commercial balance of countries in respect to price variations and labor cost in various countries. We demonstrate that the developed approach takes into account multiplicity of network links with economy interactions between countries and activity sectors thus being more efficient compared to the usual export-import analysis. The spectrum and eigenstates of G are also analyzed being related to specific activity communities of countries.

Dispenser printed electroluminescent lamps on textiles for smart fabric applications

Science.gov (United States)

de Vos, Marc; Torah, Russel; Tudor, John

2016-04-01

Flexible electroluminescent (EL) lamps are fabricated onto woven textiles using a novel dispenser printing process. Dispenser printing utilizes pressurized air to deposit ink onto a substrate through a syringe and nozzle. This work demonstrates the first use of this technology to fabricate EL lamps. The luminance of the dispenser printed EL lamps is compared to screen-printed EL lamps, both printed on textile, and also commercial EL lamps on polyurethane film. The dispenser printed lamps are shown to have a 1.5 times higher luminance than the best performing commercially available lamp, and have a comparable performance to the screen-printed lamps.

First observation of liquid-xenon proportional electroluminescence in THGEM holes

International Nuclear Information System (INIS)

Arazi, L; Itay, R; Landsman, H; Levinson, L; Pasmantirer, B; Rappaport, M L; Vartsky, D; Breskin, A; Coimbra, A E C

2013-01-01

Radiation-induced proportional-electroluminescence UV signals, emitted from the holes of a Thick Gas Electron Multiplier (THGEM) electrode immersed in liquid xenon, were recorded with a PMT for the first time. Significant photon yields were observed with gamma photons and alpha particles using a 0.4 mm thick electrode with 0.3 mm diameter holes; at 2 kV across the THGEM the photon yield was estimated to be ∼ 600 UV photons/electron over 4π. This may pave the way towards the realization of novel single-phase noble-liquid radiation detectors incorporating liquid hole-multipliers (LHM); their concept is presented

Dispenser printed electroluminescent lamps on textiles for smart fabric applications

International Nuclear Information System (INIS)

De Vos, Marc; Torah, Russel; Tudor, John

2016-01-01

Flexible electroluminescent (EL) lamps are fabricated onto woven textiles using a novel dispenser printing process. Dispenser printing utilizes pressurized air to deposit ink onto a substrate through a syringe and nozzle. This work demonstrates the first use of this technology to fabricate EL lamps. The luminance of the dispenser printed EL lamps is compared to screen-printed EL lamps, both printed on textile, and also commercial EL lamps on polyurethane film. The dispenser printed lamps are shown to have a 1.5 times higher luminance than the best performing commercially available lamp, and have a comparable performance to the screen-printed lamps. (paper)

Matrix metalloproteinase activity assays: Importance of zymography.

Science.gov (United States)

Kupai, K; Szucs, G; Cseh, S; Hajdu, I; Csonka, C; Csont, T; Ferdinandy, P

2010-01-01

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases capable of degrading extracellular matrix, including the basement membrane. MMPs are associated with various physiological processes such as morphogenesis, angiogenesis, and tissue repair. Moreover, due to the novel non-matrix related intra- and extracellular targets of MMPs, dysregulation of MMP activity has been implicated in a number of acute and chronic pathological processes, such as arthritis, acute myocardial infarction, chronic heart failure, chronic obstructive pulmonary disease, inflammation, and cancer metastasis. MMPs are considered as viable drug targets in the therapy of the above diseases. For the development of selective MMP inhibitor molecules, reliable methods are necessary for target validation and lead development. Here, we discuss the major methods used for MMP assays, focusing on substrate zymography. We highlight some problems frequently encountered during sample preparations, electrophoresis, and data analysis of zymograms. Zymography is a widely used technique to study extracellular matrix-degrading enzymes, such as MMPs, from tissue extracts, cell cultures, serum or urine. This simple and sensitive technique identifies MMPs by the degradation of their substrate and by their molecular weight and therefore helps to understand the widespread role of MMPs in different pathologies and cellular pathways. Copyright 2010 Elsevier Inc. All rights reserved.

A novel electroluminescent PPV copolymer and silsesquioxane nanocomposite film for the preparation of efficient PLED devices.

Science.gov (United States)

Venegoni, Ivan; Carniato, Fabio; Olivero, Francesco; Bisio, Chiara; Pira, Nello Li; Lambertini, Vito Guido; Marchese, Leonardo

2012-11-02

Polymer light-emitting diodes (PLEDs) have attracted growing interest in recent years for their potential use in displays and lighting fields. Nevertheless, PLED devices have some disadvantages in terms of low optoelectronic efficiency, high cost, short lifetimes and low thermal stability, which limit their final applications. Huge efforts have been made recently to improve the performances of these devices. The addition of inorganic or hybrid organic-inorganic nanoparticles to the light-emitting polymers, for example, allows their thermal stability and electroluminescent efficiency to be increased. Following this approach, novel PLED devices based on composite films of PPV-derivative copolymer (commercial name Super Yellow, SY) and octaisobutil POSS, were developed in this study. The device containing Super Yellow loaded with 1 wt% of POSS showed higher efficiency (ca. +30%) and improved lifetime in comparison to PLED prepared with the pure electroluminescent polymer. The PLED devices developed in this study are suitable candidates for automotive dashboards and, in general, for lighting applications.

Electroluminescence light emitting diodes - an environmental friendly approach

International Nuclear Information System (INIS)

Shaukat, S.F.; Farooq, R.

2005-01-01

The simple porous silicon-based devices producing stable electroluminescence (EL) by the deposition of a poly-4-dicyanomethylene-4H-cyclopenta dithiophene monolayer (PCDM) into the nanostructure was reported. The structure of these devices is Au/PCDM/porous silicon/Si/Al. The EL emission is bright, visible by the naked eye under normal daylight and broad in wavelength covering the whole visible range with a peak at 60 nm. The emission area of the devices is 1 cm/sup 2/. The El starting voltage is in the range of 14-30 V and the current is around 300 mA. The time stability was good for all the devices tested. After exposure to the air for more than three months, the devices show nearly the same emission intensity without increase of external power supplied. (author)

The effect of complexation with platinum in polyfluorene derivatives: A photo- and electro-luminescence study

International Nuclear Information System (INIS)

Assaka, Andressa M.; Hu Bin; Mays, Jimmy; Iamazaki, Eduardo T.; Atvars, Teresa D.Z.; Akcelrud, Leni

2011-01-01

The synthesis and characterization of a polymeric structure containing fluorene units statistically linked to 3-cyclohexyl-thiophene and bipyridine PFOTBipy-poly[(4-hexylthiophene-2,5-diyl)(9,9-dihexyl-fluoren-2,7-diyl) -co-(bipyridine-5.5'-diyl)(9,9-dihexyl-fluoren-2,7-diyl)], is reported. The complexation with platinum was possible through the bipyridil units present in 10%, 50% and 100% content. The structure has a fluorenyl moiety between each bipyridine and thiophene groups resulting in a stable and efficient light-emitting polymeric material combining the well known emissive properties of fluorene, the charge mobility generated by thiophene and the electron-transfer properties of a metal complex as well. All the polymers were photo and electroluminescent materials, and showed phosphorescence at low temperatures. Photoluminescence properties were studied by steady state and time resolved spectroscopy and showed changes of both emission peak and relative intensity of the emission bands depending on the relative amount of the platinum complex. The electroluminescence followed the trends found for photoluminescence. The blue emission of the copolymer without platinum is due to the fluorenyl segments and for higher complex contents the emission is characteristic of the aggregates involving the bipyridinyl moieties. Therefore, emission color can be tuned by the complex content. The turn-on voltage was strongly reduced from 22 to 8 V for the 100% complexed copolymer, as compared to the device made with the non complexed one, but the luminance decreased, due to quenching or trapping effects. - Research Highlights: →Statistic copolymer containing fluorine, thiophene and bipyridine. →Complexation of platinum with platinum with bipyridine. →Electroluminescence and electrophosphorescence at low temperatures. →Emission color can be tuned by the complex content.

New intracellular activities of matrix metalloproteinases shine in the moonlight.

Science.gov (United States)

Jobin, Parker G; Butler, Georgina S; Overall, Christopher M

2017-11-01

Adaption of a single protein to perform multiple independent functions facilitates functional plasticity of the proteome allowing a limited number of protein-coding genes to perform a multitude of cellular processes. Multifunctionality is achievable by post-translational modifications and by modulating subcellular localization. Matrix metalloproteinases (MMPs), classically viewed as degraders of the extracellular matrix (ECM) responsible for matrix protein turnover, are more recently recognized as regulators of a range of extracellular bioactive molecules including chemokines, cytokines, and their binders. However, growing evidence has convincingly identified select MMPs in intracellular compartments with unexpected physiological and pathological roles. Intracellular MMPs have both proteolytic and non-proteolytic functions, including signal transduction and transcription factor activity thereby challenging their traditional designation as extracellular proteases. This review highlights current knowledge of subcellular location and activity of these "moonlighting" MMPs. Intracellular roles herald a new era of MMP research, rejuvenating interest in targeting these proteases in therapeutic strategies. This article is part of a Special Issue entitled: Matrix Metalloproteinases edited by Rafael Fridman. Copyright © 2017 Elsevier B.V. All rights reserved.

Electroluminescence from completely horizontally oriented dye molecules

Energy Technology Data Exchange (ETDEWEB)

Komino, Takeshi [Education Center for Global Leaders in Molecular System for Devices, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Center for Organic Photonics and Electronics Research, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Japan Science and Technology Agency, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Sagara, Yuta [Center for Organic Photonics and Electronics Research, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Tanaka, Hiroyuki [Center for Organic Photonics and Electronics Research, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Oki, Yuji [Japan Science and Technology Agency, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Department of Electronics, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Nakamura, Nozomi [Center for Organic Photonics and Electronics Research, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Fujimoto, Hiroshi [Center for Organic Photonics and Electronics Research, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Fukuoka i" 3-Center for Organic Photonics and Electronics Research (i3-OPERA), Fukuoka 819-0388 (Japan); and others

2016-06-13

A complete horizontal molecular orientation of a linear-shaped thermally activated delayed fluorescent guest emitter 2,6-bis(4-(10Hphenoxazin-10-yl)phenyl)benzo[1,2-d:5,4-d′] bis(oxazole) (cis-BOX2) was obtained in a glassy host matrix by vapor deposition. The orientational order of cis-BOX2 depended on the combination of deposition temperature and the type of host matrix. Complete horizontal orientation was obtained when a thin film with cis-BOX2 doped in a 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) host matrix was fabricated at 200 K. The ultimate orientation of guest molecules originates from not only the kinetic relaxation but also the kinetic stability of the deposited guest molecules on the film surface during film growth. Utilizing the ultimate orientation, a highly efficient organic light-emitting diode with the external quantum efficiency of 33.4 ± 2.0% was realized. The thermal stability of the horizontal orientation of cis-BOX2 was governed by the glass transition temperature (T{sub g}) of the CBP host matrix; the horizontal orientation was stable unless the film was annealed above T{sub g}.

Electroluminescence Spectrum Shift with Switching Behaviour of Diamond Thin Films

Institute of Scientific and Technical Information of China (English)

王小平; 王丽军; 张启仁; 姚宁; 张兵临

2003-01-01

We report a special phenomenon on switching behaviour and the electroluminescence (EL) spectrum shift of doped diamond thin films. Nitrogen and cerium doped diamond thin films were deposited on a silicon substrate by microwave plasma-assisted chemical vapour deposition system and other special techniques. An EL device with a three-layer structure of nitrogen doped diamond/cerium doped diamond/SiO2 thin films was made. The EL device was driven by a direct-current power supply. Its EL character has been investigated, and a switching behaviour was observed. The EL light emission colour of diamond films changes from yellow (590nm) to blue (454 nm) while the switching behaviour appears.

Exciplex electroluminescence and photoluminescence spectra of the new organic materials based on zinc complexes of sulphanylamino-substituted ligands.

Science.gov (United States)

Kaplunov, Mikhail G; Krasnikova, Svetlana S; Nikitenko, Sergey L; Sermakasheva, Natalia L; Yakushchenko, Igor K

2012-04-03

We have investigated the electroluminescence spectra of the electroluminescent devices based on the new zinc complexes of amino-substituted benzothiazoles and quinolines containing the C-N-M-N chains in their chelate cycles. The spectra exhibit strong exciplex bands in the green to yellow region 540 to 590 nm due to interaction of the excited states of zinc complexes and triaryl molecules of the hole-transporting layer. For some devices, the intrinsic luminescence band of 460 nm in the blue region is also observed along with the exciplex band giving rise to an almost white color of the device emission. The exciplex band can be eliminated if the material of the hole-transporting layer is not a triarylamine derivative. We have also found the exciplex emission in the photoluminescence spectra of the films containing blends of zinc complex and triphenylamine material.

Electroluminescence from single-wall carbon nanotube network transistors.

Science.gov (United States)

Adam, E; Aguirre, C M; Marty, L; St-Antoine, B C; Meunier, F; Desjardins, P; Ménard, D; Martel, R

2008-08-01

The electroluminescence (EL) properties from single-wall carbon nanotube network field-effect transistors (NNFETs) and small bundle carbon nanotube field effect transistors (CNFETs) are studied using spectroscopy and imaging in the near-infrared (NIR). At room temperature, NNFETs produce broad (approximately 180 meV) and structured NIR spectra, while they are narrower (approximately 80 meV) for CNFETs. EL emission from NNFETs is located in the vicinity of the minority carrier injecting contact (drain) and the spectrum of the emission is red shifted with respect to the corresponding absorption spectrum. A phenomenological model based on a Fermi-Dirac distribution of carriers in the nanotube network reproduces the spectral features observed. This work supports bipolar (electron-hole) current recombination as the main mechanism of emission and highlights the drastic influence of carrier distribution on the optoelectronic properties of carbon nanotube films.

Electroluminescence properties of Si MOS structures with incorporation of FeSi2 precipitates formed by iron implantation

International Nuclear Information System (INIS)

Chow, C.F.; Wong, S.P.; Gao, Y.; Ke, N.; Li, Q.; Cheung, W.Y.; Lourenco, M.A.; Homewood, K.P.

2005-01-01

Silicon MOS structures with FeSi 2 precipitates embedded in the MOS active region have been fabricated and the electroluminescence (EL) properties from these FeSi 2 -Si MOS structures were measured as a function of temperature from 80 K to 300 K. Clear EL signals were observed even at room temperature for samples prepared at appropriate processing conditions. The EL spectra consist of two peaks, one attributed to FeSi 2 and the other attributed to Si band edge emission. While the intensity of the FeSi 2 peak showed the usual thermal quenching behavior, the Si band edge emission showed the opposite trend with its intensity increased with increasing temperature. Details of the line shapes and their temperature dependence are analyzed and discussed

Kinematic matrix theory and universalities in self-propellers and active swimmers.

Science.gov (United States)

Nourhani, Amir; Lammert, Paul E; Borhan, Ali; Crespi, Vincent H

2014-06-01

We describe an efficient and parsimonious matrix-based theory for studying the ensemble behavior of self-propellers and active swimmers, such as nanomotors or motile bacteria, that are typically studied by differential-equation-based Langevin or Fokker-Planck formalisms. The kinematic effects for elementary processes of motion are incorporated into a matrix, called the "kinematrix," from which we immediately obtain correlators and the mean and variance of angular and position variables (and thus effective diffusivity) by simple matrix algebra. The kinematrix formalism enables us recast the behaviors of a diverse range of self-propellers into a unified form, revealing universalities in their ensemble behavior in terms of new emergent time scales. Active fluctuations and hydrodynamic interactions can be expressed as an additive composition of separate self-propellers.

SPARC regulates extracellular matrix organization through its modulation of integrin-linked kinase activity.

Science.gov (United States)

Barker, Thomas H; Baneyx, Gretchen; Cardó-Vila, Marina; Workman, Gail A; Weaver, Matt; Menon, Priya M; Dedhar, Shoukat; Rempel, Sandra A; Arap, Wadih; Pasqualini, Renata; Vogel, Viola; Sage, E Helene

2005-10-28

SPARC, a 32-kDa matricellular glycoprotein, mediates interactions between cells and their extracellular matrix, and targeted deletion of Sparc results in compromised extracellular matrix in mice. Fibronectin matrix provides provisional tissue scaffolding during development and wound healing and is essential for the stabilization of mature extracellular matrix. Herein, we report that SPARC expression does not significantly affect fibronectin-induced cell spreading but enhances fibronectin-induced stress fiber formation and cell-mediated partial unfolding of fibronectin molecules, an essential process in fibronectin matrix assembly. By phage display, we identify integrin-linked kinase as a potential binding partner of SPARC and verify the interaction by co-immunoprecipitation and colocalization in vitro. Cells lacking SPARC exhibit diminished fibronectin-induced integrin-linked kinase activation and integrin-linked kinase-dependent cell-contractile signaling. Furthermore, induced expression of SPARC in SPARC-null fibroblasts restores fibronectin-induced integrin-linked kinase activation, downstream signaling, and fibronectin unfolding. These data further confirm the function of SPARC in extracellular matrix organization and identify a novel mechanism by which SPARC regulates extracellular matrix assembly.

Electroluminescence from GaN-polymer heterojunction

International Nuclear Information System (INIS)

Chitara, Basant; Lal, Nidhi; Krupanidhi, S.B.; Rao, C.N.R.

2011-01-01

Inorganic and organic semiconductor devices are generally viewed as distinct and separate technologies. Herein we report a hybrid inorganic-organic light-emitting device employing the use of an air stable polymer, Poly (9,9-dioctylfluorene-alt-benzothiadiazole) as a p-type layer to create a heterojunction, avoiding the use of p-type GaN, which is difficult to grow, being prone to the complex and expensive fabrication techniques that characterises it. I-V characteristics of the GaN-polymer heterojunction fabricated by us exhibits excellent rectification. The luminescence onset voltage is typically about 8-10 V. The device emits yellowish white electroluminescence with CIE coordinates (0.42, 0.44). - Highlights: → We use a polymer Poly (9,9-dioctylfluorene-alt-benzothiadiazole) as a p-type layer to create a heterojunction. → I-V characteristics of the device fabricated by us exhibits excellent rectification. → The p-type polymer also emits yellow light, which when combined in proper composition with GaN, give rise to white light. → Device can be readily fabricated by just spin coating the polymer over GaN reducing the cost of the device.

Electroluminescence of doped and undoped AlN/SiC-heterojunctions

Energy Technology Data Exchange (ETDEWEB)

Bruesewitz, Christoph; Vetter, Ulrich; Hofsaess, Hans [II. Physikalisches Institut, Georg-August-Universitaet Goettingen (Germany)

2010-07-01

AlN with its large and direct bandgap is a useful host for optoelectronic applications. Grown on 6H-SiC, a heterojunction is created, forming a diode. The light emitted by n-doped 6H-SiC via electroluminescence forms a broad band with a maximum at a wavelength of 475 nm. With the AlN layer on the surface, nitrogen atoms can diffuse into the 6H-SiC, creating new energy levels. Depending on the direction of the current and additional dopants in the AlN layer, the carrier concentration changes and new levels are available, resulting in different colours. It is shown that in this heterojunction blue, red and white colours are feasible.

ASTM and VAMAS activities in titanium matrix composites test methods development

Science.gov (United States)

Johnson, W. S.; Harmon, D. M.; Bartolotta, P. A.; Russ, S. M.

1994-01-01

Titanium matrix composites (TMC's) are being considered for a number of aerospace applications ranging from high performance engine components to airframe structures in areas that require high stiffness to weight ratios at temperatures up to 400 C. TMC's exhibit unique mechanical behavior due to fiber-matrix interface failures, matrix cracks bridged by fibers, thermo-viscoplastic behavior of the matrix at elevated temperatures, and the development of significant thermal residual stresses in the composite due to fabrication. Standard testing methodology must be developed to reflect the uniqueness of this type of material systems. The purpose of this paper is to review the current activities in ASTM and Versailles Project on Advanced Materials and Standards (VAMAS) that are directed toward the development of standard test methodology for titanium matrix composites.

Activity of matrix metalloproteinases during antimycobacterial therapy in mice with simulated tuberculous inflammation.

Science.gov (United States)

Sumenkova, D V; Russkikh, G S; Poteryaeva, O N; Polyakov, L M; Panin, L E

2013-05-01

Matrix metalloproteinases are shown to be involved in the pathogenesis of tuberculosis inflammation. In the early stages of BCG-granuloma formation in mouse liver and lungs, the serum levels of matrix metalloproteinases 2 and 7 increased by 4.5 times and remained unchanged while the pathology developed. Antimycobacterial therapy with isoniazid reduced enzyme activity almost to the level of intact control. The decrease in activity of matrix metalloproteinases 2 and 7 that play the most prominent role in the development of destructive forms of tuberculosis is of great therapeutic importance.

Immobilization of mercury and zinc in an alkali-activated slag matrix.

Science.gov (United States)

Qian, Guangren; Sun, Darren Delai; Tay, Joo Hwa

2003-07-04

The behavior of heavy metals mercury and zinc immobilized in an alkali-activated slag (AAS) matrix has been evaluated using physical property tests, pore structure analysis and XRD, TG-DTG, FTIR and TCLP analysis. Low concentrations (0.5%) of mercury and zinc ions had only a slight affect on compressive strength, pore structure and hydration of AAS matrixes. The addition of 2% Hg ions to the AAS matrix resulted in a reduction in early compressive strength but no negative effects were noticed after 28 days of hydration. Meanwhile, 2% Hg ions can be effectively immobilized in the AAS matrix with the leachate meeting the USEPA TCLP mercury limit. For a 2% Zn-doped AAS matrix, the hydration of the AAS paste was greatly retarded and the zinc concentration in the leachate from this matrix was higher than 5mg/l even at 28 days. Based on these results, we conclude that the physical encapsulation and chemical fixation mechanisms were likely to be responsible for the immobilization of Hg ions in the AAS matrix while only chemical fixation mechanisms were responsible for the immobilization of Zn ions in the AAS matrix.

A hands-on activity for teaching product-process matrix: roadmap and application

Directory of Open Access Journals (Sweden)

Luciano Costa Santos

2014-08-01

Full Text Available The product-process matrix is a well-known framework proposed by Hayes and Wheelwright (1979 that is commonly used to identify processes types and to analyze the alignment of these processes with the products of a company. For didactic purposes, the matrix helps undergraduates beginners from Production Engineering to understand the logic of production systems, providing knowledge that will be essential for various course subjects. Considering the high level of abstraction of the concepts underlying the product-process matrix, this paper presents a way to facilitate the learning of them through the application of a hands-on activity which relies on the active learning philosophy. The proposed dynamic uses colored plastic sheets and PVC pipes as main materials, differing from the original proposal of Penlesky and Treleven (2005 . In addition to presenting an extremely simple exercise, which encourages its application in the classroom, another contribution of this paper is to define a complete roadmap for conducting the activity. This roadmap describes the assembly of fictitious products in customization and standardization scenarios for the comparison of two processes types of product-process matrix, job shop and assembly line. The activity revealed very successful after its application to two groups of Production Engineering undergraduates, confirmed with positive feedback from the students surveyed.

Matrix metalloproteinases with gelatinolytic activity induced by Paracoccidioides brasiliensis infection

Science.gov (United States)

Nishikaku, Angela Satie; Ribeiro, Luciana Cristina; Molina, Raphael Fagnani Sanchez; Albe, Bernardo Paulo; Cunha, Cláudia da Silva; Burger, Eva

2009-01-01

Matrix metalloproteinases (MMPs) modulate extracellular matrix turnover, inflammation and immunity. We studied MMP-9 and MMP-2 in experimental paracoccidioidomycosis. At 15 and 120 days after infection (DAI) with virulent Paracoccidioides brasiliensis, MMP-9 was positive by immunohistochemistry in multinucleated giant cells, in mononuclear cells with macrophage and lymphocyte morphologies and also in fungal cells in the lesions of susceptible and resistant mice. Using gelatin zymography, pro- and active MMP-9 and active MMP-2 were detected in all infected mice, but not in controls. Gelatinolytic activity was not observed in P. brasiliensis extracts. Semiquantitative analysis of gelatinolytic activities revealed weak or absent MMP-2 and strong MMP-9 activity in both mouse strains at 15 DAI, declining at 120 DAI. Avirulent P. brasiliensis-infected mice had residual lesions with MMP-9-positive pseudoxantomatous macrophages, but no gelatinase activity at 120 DAI. Our findings demonstrate the induction of MMPs, particularly MMP-9, in experimental paracoccidioidomycosis, suggesting a possible influence in the pattern of granulomas and in fungal dissemination. PMID:19765107

Photo and electroluminescence of porous silicon layers

International Nuclear Information System (INIS)

Keshmini, S.H.; Samadpour, S.; Haji-Ali, E.; Rokn-Abadi, M.R.

1995-01-01

Porous silicon (PSi) layers were prepared by both chemical and electrochemical methods on n- and p-type Si substrates. In the former technique, light emission was obtained from p-type and n-type samples. It was found that intense light illumination during the preparation process was essential for PSi formation on n-type substrates. An efficient electrochemical cell with some useful features was designed for electrochemical etching of silicon. Various preparation parameters were studied and photoluminescence emissions ranging from dark red to light blue were obtained from PSi samples prepared on p-type substrates. N-type samples produced emission ranging from dark red to orange yellow. Electroluminescence of porous silicon samples showed that the color of the emission was the same as the photoluminescence color of the sample, and its intensity and duration depended on the current density passed through the sample. The effects of exposure of samples to air, storage in vacuum and heat treatment in air on luminescence intensity of the samples and preparation of patterned porous layers were also studied. (author)

Superoxide activates mitochondrial uncoupling protein 2 from the matrix side. Studies using targeted antioxidants.

Science.gov (United States)

Echtay, Karim S; Murphy, Michael P; Smith, Robin A J; Talbot, Darren A; Brand, Martin D

2002-12-06

Superoxide activates nucleotide-sensitive mitochondrial proton transport through the uncoupling proteins UCP1, UCP2, and UCP3 (Echtay, K. S., et al. (2002) Nature 415, 1482-1486). Two possible mechanisms were proposed: direct activation of the UCP proton transport mechanism by superoxide or its products and a cycle of hydroperoxyl radical entry coupled to UCP-catalyzed superoxide anion export. Here we provide evidence for the first mechanism and show that superoxide activates UCP2 in rat kidney mitochondria from the matrix side of the mitochondrial inner membrane: (i) Exogenous superoxide inhibited matrix aconitase, showing that external superoxide entered the matrix. (ii) Superoxide-induced uncoupling was abolished by low concentrations of the mitochondrially targeted antioxidants 10-(6'-ubiquinonyl)decyltriphenylphosphonium (mitoQ) or 2-[2-(triphenylphosphonio)ethyl]-3,4-dihydro-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol bromide (mitoVit E), which are ubiquinone (Q) or tocopherol derivatives targeted to the matrix by covalent attachment to triphenylphosphonium cation. However, superoxide-induced uncoupling was not affected by similar concentrations of the nontargeted antioxidants Q(o), Q(1), decylubiquinone, vitamin E, or 6-hydroxy-2,5,7,8-tetramethylchroman 2-carboxylic acid (TROLOX) or of the mitochondrially targeted but redox-inactive analogs decyltriphenylphosphonium or 4-chlorobutyltriphenylphosphonium. Thus matrix superoxide appears to be necessary for activation of UCP2 by exogenous superoxide. (iii) When the reduced to oxidized ratio of mitoQ accumulated by mitochondria was increased by inhibiting cytochrome oxidase, it induced nucleotide-sensitive uncoupling that was not inhibited by external superoxide dismutase. Under these conditions quinols are known to produce superoxide, and because mitoQ is localized within the mitochondrial matrix this suggests that production of superoxide in the matrix was sufficient to activate UCP2. Furthermore, the superoxide

Quantification of Solar Cell Failure Signatures Based on Statistical Analysis of Electroluminescence Images

DEFF Research Database (Denmark)

Spataru, Sergiu; Parikh, Harsh; Hacke, Peter

2017-01-01

We demonstrate a method to quantify the extent of solar cell cracks, shunting, or damaged cell interconnects, present in crystalline silicon photovoltaic (PV) modules by statistical analysis of the electroluminescence (EL) intensity distributions of individual cells within the module. From the EL...... intensity distributions (ELID) of each cell, we calculated summary statistics such as standard deviation, median, skewness and kurtosis, and analyzed how they correlate with the magnitude of the solar cell degradation. We found that the dispersion of the ELID increases with the size and severity...

Electrochemical synthesis of MoS2 quantum dots embedded nanostructured porous silicon with enhanced electroluminescence property

Science.gov (United States)

Shrivastava, Megha; Kumari, Reeta; Parra, Mohammad Ramzan; Pandey, Padmini; Siddiqui, Hafsa; Haque, Fozia Z.

2017-11-01

In this report we present the successful enhancement in electroluminescence (EL) in nanostructured n-type porous silicon (PS) with an idea of embedding luminophorous Molybdenum disulfide (MoS2) quantum dots (QD's). Electrochemical anodization technique was used for the formation of PS surface and MoS2 QD's were prepared using the electrochemical route. Spin coating technique was employed for the proper incorporation of MoS2 QD's within the PS nanostructures. The crystallographic analysis was performed using X-ray diffraction (XRD), Raman and Fourier transform infrared (FT-IR) spectroscopy techniques. However, surface morphology was determined using Transmission electron microscopy (TEM) and Atomic force microscopy (AFM). The optical measurements were performed on photoluminescence (PL) spectrophotometer; additionally for electroluminescence (EL) study special arrangement of instrumental setup was made at laboratory level which provides novelty to this work. A diode prototype was made comprising Ag/MoS2:PS/Silicon/Ag for EL study. The MoS2:PS shows a remarkable concentration dependent enhancement in PL as well as in EL intensities, which paves a way to better utilize this strategy in optoelectronic device applications.

Magnetic field enhanced electroluminescence in organic light emitting diodes based on electron donor-acceptor exciplex blends

Science.gov (United States)

Baniya, Sangita; Basel, Tek; Sun, Dali; McLaughlin, Ryan; Vardeny, Zeev Valy

2016-03-01

A useful process for light harvesting from injected electron-hole pairs in organic light emitting diodes (OLED) is the transfer from triplet excitons (T) to singlet excitons (S) via reverse intersystem crossing (RISC). This process adds a delayed electro-luminescence (EL) emission component that is known as thermally activated delayed fluorescence (TADF). We have studied electron donor (D)/acceptor(A) blends that form an exciplex manifold in which the energy difference, ΔEST between the lowest singlet (S1) and triplet (T1) levels is relatively small (exciplex blend is enhanced up to 40% by applying a relatively weak magnetic field of 50 mT at ambient. Moreover the MEL response is activated with activation energy similar that of the EL emission. This suggests that the large magneto-EL originates from an additional spin-mixing channel between singlet and triplet states of the generated exciplexes, which is due to TADF. We will report on the MEL dependencies on the temperature, bias voltage, and D-A materials for optimum OLED performance. Supported by SAMSUNG Global Research Outreach (GRO) program, and also by the NSF-Material Science & Engineering Center (MRSEC) program at the University of Utah (DMR-1121252).

Electroluminescence dependence on the organic thickness in ZnO nano rods/Alq3 heterostructure devices.

Science.gov (United States)

Kan, Pengzhi; Wang, Yongsheng; Zhao, Suling; Xu, Zheng; Wang, Dawei

2011-04-01

ZnO nanorods are synthesised by a hydrothermal method on ITO glass. Their crystallization and morphology are detected by XRD and SEM, respectively. The results show that the ZnO nanorod array has grown primarily along a direction aligned perpendicular to the ITO substrate. The average height and diameter of the nanorods is about 130 nm and 30 nm, respectively. Then ZnO nano rods/Alq3 heterostructure LEDs are prepared by thermal evaporation of Alq3 molecules. The thicknesses of the Alq3 layers are 130 nm, 150 nm, 170 nm and 190 nm, respectively. The electroluminescence of the devices is detected under different DC bias voltages. The exciton emission of Alq3 is detected in all devices. When the thickness of Alq3 is 130 nm, the UV electroluminescence of ZnO is around 382 nm, and defect emissions around 670 nm and 740 nm are detected. Defect emissions of ZnO nanorods are prominent. When the thickness of Alq3 increases to over 170 nm, it is difficult to observe defect emissions from the ZnO nano rods. In such devices, the exciton emission of Alq3 is more prominent than other emissions under different bias voltage.

Electroluminescence of zinc oxide thin-films prepared via polymeric precursor and via sol-gel methods

International Nuclear Information System (INIS)

Lima, S.A.M.; Cremona, M.; Davolos, M.R.; Legnani, C.; Quirino, W.G.

2007-01-01

Zinc oxide (ZnO) is an electroluminescent (EL) material that can emit light in different regions of electromagnetic spectrum when electrically excited. Since ZnO is chemically stable, inexpensive and environmentally friendly material, its EL property can be useful to construct solid-state lamps for illumination or as UV emitter. We present here two wet chemical methods to prepare ZnO thin-films: the Pechini method and the sol-gel method, with both methods resulting in crystalline and transparent films with transmittance >85% at 550 nm. These films were used to make thin-film electroluminescent devices (TFELD) using two different insulator layers: lithium fluoride (LiF) or silica (SiO 2 ). All the devices exhibit at least two wide emission bands in the visible range centered at 420 nm and at 380 nm attributed to the electronic defects in the ZnO optical band gap. Besides these two bands, the device using SiO 2 and ZnO film obtained via sol-gel exhibits an additional band in the UV range centered at 350 nm which can be attributed to excitonic emission. These emission bands of ZnO can transfer their energy when a proper dopant is present. For the devices produced the voltage-current characteristics were measured in a specific range of applied voltage

Progress and Prospects in Stretchable Electroluminescent Devices

Directory of Open Access Journals (Sweden)

Wang Jiangxin

2017-03-01

Full Text Available Stretchable electroluminescent (EL devices are a new form of mechanically deformable electronics that are gaining increasing interests and believed to be one of the essential technologies for next generation lighting and display applications. Apart from the simple bending capability in flexible EL devices, the stretchable EL devices are required to withstand larger mechanical deformations and accommodate stretching strain beyond 10%. The excellent mechanical conformability in these devices enables their applications in rigorous mechanical conditions such as flexing, twisting, stretching, and folding.The stretchable EL devices can be conformably wrapped onto arbitrary curvilinear surface and respond seamlessly to the external or internal forces, leading to unprecedented applications that cannot be addressed with conventional technologies. For example, they are in demand for wide applications in biomedical-related devices or sensors and soft interactive display systems, including activating devices for photosensitive drug, imaging apparatus for internal tissues, electronic skins, interactive input and output devices, robotics, and volumetric displays. With increasingly stringent demand on the mechanical requirements, the fabrication of stretchable EL device is encountering many challenges that are difficult to resolve. In this review, recent progresses in the stretchable EL devices are covered with a focus on the approaches that are adopted to tackle materials and process challenges in stretchable EL devices and delineate the strategies in stretchable electronics. We first introduce the emission mechanisms that have been successfully demonstrated on stretchable EL devices. Limitations and advantages of the different mechanisms for stretchable EL devices are also discussed. Representative reports are reviewed based on different structural and material strategies. Unprecedented applications that have been enabled by the stretchable EL devices are

Quantification of solar cell failure signatures based on statistical analysis of electroluminescence images

DEFF Research Database (Denmark)

Spataru, Sergiu; Parikh, Harsh; Benatto, Gisele Alves dos Reis

2017-01-01

We propose a method to identify and quantify the extent of solar cell cracks, shunting, or damaged cell interconnects, present in crystalline silicon photovoltaic (PV) modules by statistical analysis of the electroluminescence (EL) intensity distributions of individual cells within the module. From...... the EL intensity distributions (ELID) of each cell, we calculated summary statistics such as standard deviation, median, skewness and kurtosis, and analyzed how they correlate with the type of the solar cell degradation. We found that the dispersion of the ELID increases with the size and severity...

Molecular-scale simulation of electroluminescence in a multilayer white organic light-emitting diode

DEFF Research Database (Denmark)

Mesta, Murat; Carvelli, Marco; de Vries, Rein J

2013-01-01

we show that it is feasible to carry out Monte Carlo simulations including all of these molecular-scale processes for a hybrid multilayer organic light-emitting diode combining red and green phosphorescent layers with a blue fluorescent layer. The simulated current density and emission profile......In multilayer white organic light-emitting diodes the electronic processes in the various layers--injection and motion of charges as well as generation, diffusion and radiative decay of excitons--should be concerted such that efficient, stable and colour-balanced electroluminescence can occur. Here...

Electroluminescence and charge photogeneration in poly(9,9-dihexadecylfluorene-2,7-diyl) and its blends

Czech Academy of Sciences Publication Activity Database

Cimrová, Věra; Výprachtický, Drahomír

2004-01-01

Roč. 212, č. 1 (2004), s. 281-286 ISSN 1022-1360. [Electrical and Related Properties of Polymers and Other Organic Solids /9./. Prague, 14.07.2002-18.07.2002] R&D Projects: GA ČR GA203/01/0512; GA ČR GA102/98/0696 Institutional research plan: CEZ:AV0Z4050913 Keywords : electroluminescence * LEDs * poly(1,4-phenylene)s Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.691, year: 2004

Electroluminescence from a n-ZnO/p-GaN hybrid LED

Energy Technology Data Exchange (ETDEWEB)

Behrends, Arne; Bakin, Andrey; Waag, Andreas [Institute of Semiconductor Technology, Hans-Sommer Str. 66, 38106 Braunschweig (Germany); Kwack, Ho-Sang; Dang, Le Si [Institut Neel, CNRS-UJF, 25, rue des Martyrs, 38042 Grenoble (France)

2010-06-15

In this work we report on the fabrication and characterization of a n-ZnO/p-GaN heterojunction LED. The p-GaN layer was fabricated using MOCVD on Al{sub 2}O{sub 3} with Mg as the acceptor whereas the ZnO nanostructures were grown in a very simple vapor transport system without any additionally doping. Room temperature electroluminescence (EL) measurements show green deep band emission centered at 2.3 eV which is clearly visible with the naked eye when the structure is forward biased. Cathodoluminescence mapping was performed to explain the absence of the band edge emission in the EL spectrum. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Temperature and current dependent electroluminescence measurements on colour-coded multiple quantum well light emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Bergbauer, Werner [OSRAM Opto Semiconductors GmbH, Regensburg (Germany); FH Deggendorf (Germany); Laubsch, Ansgar; Peter, Matthias; Mayer, Tobias; Bader, Stefan; Oberschmid, Raimund; Hahn, Berthold [OSRAM Opto Semiconductors GmbH, Regensburg (Germany); Benstetter, Guenther [FH Deggendorf (Germany)

2008-07-01

As the efficiency and the luminous flux have been increased enormously in the last few years, today Light Emitting Diodes (LEDs) are even pushed to applications like general lighting and Home Cinema Projection. Still, InGaN/GaN heterostructure based LEDs suffer from loss-mechanisms like non-radiative defect and Auger recombination, carrier leakage and piezo-field induced carrier separation. To optimize the high current efficiency we evaluated the benefit of Multiple Quantum Well (MQW) compared to Single Quantum Well (SQW) LEDs. Temperature dependent electroluminescence of colour-coded structures with different Indium content in certain Quantum Wells was measured. The experiments demonstrated a strong temperature and current dependence of the MQW operation. The comparison between different LED structures showed effectively the increased LED performance of those structures which operate with a well adjusted MQW active area. Due to the enhanced carrier distribution in the high current range, these LEDs show a higher light output and additionally a reduced wavelength shift.

Temperature and current dependent electroluminescence measurements on colour-coded multiple quantum well light emitting diodes

International Nuclear Information System (INIS)

Bergbauer, Werner; Laubsch, Ansgar; Peter, Matthias; Mayer, Tobias; Bader, Stefan; Oberschmid, Raimund; Hahn, Berthold; Benstetter, Guenther

2008-01-01

As the efficiency and the luminous flux have been increased enormously in the last few years, today Light Emitting Diodes (LEDs) are even pushed to applications like general lighting and Home Cinema Projection. Still, InGaN/GaN heterostructure based LEDs suffer from loss-mechanisms like non-radiative defect and Auger recombination, carrier leakage and piezo-field induced carrier separation. To optimize the high current efficiency we evaluated the benefit of Multiple Quantum Well (MQW) compared to Single Quantum Well (SQW) LEDs. Temperature dependent electroluminescence of colour-coded structures with different Indium content in certain Quantum Wells was measured. The experiments demonstrated a strong temperature and current dependence of the MQW operation. The comparison between different LED structures showed effectively the increased LED performance of those structures which operate with a well adjusted MQW active area. Due to the enhanced carrier distribution in the high current range, these LEDs show a higher light output and additionally a reduced wavelength shift

Electroluminescence of Multicomponent Conjugated Polymers. 1. Roles of Polymer/Polymer Interfaces in Emission Enhancement and Voltage-Tunable Multicolor Emission in Semiconducting Polymer/Polymer Heterojunctions

National Research Council Canada - National Science Library

Zhang, Xuejun, Ph.D

1999-01-01

Effects of the electronic structure of polymer/polymer interfaces on the electroluminescence efficiency and tunable multicolor emission of polymer heterojunction light-emitting diodes were explored...

Enhancement of electroluminescence from embedded Si quantum dots/SiO2multilayers film by localized-surface-plasmon and surface roughening.

Science.gov (United States)

Li, Wei; Wang, Shaolei; Hu, Mingyue; He, Sufeng; Ge, Pengpeng; Wang, Jing; Guo, Yan Yan; Zhaowei, Liu

2015-07-03

In this paper, we prepared a novel structure to enhance the electroluminescence intensity from Si quantum dots/SiO2multilayers. An amorphous Si/SiO2 multilayer film was fabricated by plasma-enhanced chemical vapor deposition on a Pt nanoparticle (NP)-coated Si nanopillar array substrate. By thermal annealing, an embedded Si quantum dot (QDs)/SiO2 multilayer film was obtained. The result shows that electroluminescence intensity was significantly enhanced. And, the turn-on voltage of the luminescent device was reduced to 3 V. The enhancement of the light emission is due to the resonance coupling between the localized-surface-plasmon (LSP) of Pt NPs and the band-gap emission of Si QDs/SiO2 multilayers. The other factors were the improved absorption of excitation light and the increase of light extraction ratio by surface roughening structures. These excellent characteristics are promising for silicon-based light-emitting applications.

Influence of tool pin in friction stir welding on activated carbon reinforced aluminium metal matrix composite

Science.gov (United States)

DijuSamuel, G.; Raja Dhas, J. Edwin

2017-10-01

This paper focus on impact of tool pin in friction stir welding on activated carbon reinforced aluminium metal matrix composite. For fabrication of metal matrix composite AA6061 is used as matrix and activated carbon is used as reinforcement and it is casted using modified stir casting technique. After casting metal matrix composite has undergone various microstructure tests like SEM,EDAX and XRD. FSW is carried out in this metal matrix composite by choosing various tool pin profile like square,round,Threaded round, hexagon and taper. The quality of welded plates is measured in terms of ultimate tensile strength and hardness.

Matrix viscoplasticity and its shielding by active mechanics in microtissue models: experiments and mathematical modeling

Science.gov (United States)

Liu, Alan S.; Wang, Hailong; Copeland, Craig R.; Chen, Christopher S.; Shenoy, Vivek B.; Reich, Daniel H.

2016-01-01

The biomechanical behavior of tissues under mechanical stimulation is critically important to physiological function. We report a combined experimental and modeling study of bioengineered 3D smooth muscle microtissues that reveals a previously unappreciated interaction between active cell mechanics and the viscoplastic properties of the extracellular matrix. The microtissues’ response to stretch/unstretch actuations, as probed by microcantilever force sensors, was dominated by cellular actomyosin dynamics. However, cell lysis revealed a viscoplastic response of the underlying model collagen/fibrin matrix. A model coupling Hill-type actomyosin dynamics with a plastic perfectly viscoplastic description of the matrix quantitatively accounts for the microtissue dynamics, including notably the cells’ shielding of the matrix plasticity. Stretch measurements of single cells confirmed the active cell dynamics, and were well described by a single-cell version of our model. These results reveal the need for new focus on matrix plasticity and its interactions with active cell mechanics in describing tissue dynamics. PMID:27671239

Hole-exciton interaction induced high field decay of magneto-electroluminescence in Alq3-based organic light-emitting diodes at room temperature

Science.gov (United States)

Zhang, Tingting; Holford, D. F.; Gu, Hang; Kreouzis, T.; Zhang, Sijie; Gillin, W. P.

2016-01-01

The magnetic field effects on the electroluminescence of aluminium tris-(8-hydroxyqinoline) (Alq3) based organic light emitting diodes have been investigated by varying the electron/hole ratio in the emissive layer. Experimental results reveal that a negative high field effect in the magneto-electroluminescence (MEL) can be found in devices with very low triplet exciton concentration at room temperature. This suggests triplet-triplet annihilation cannot be used to explain the negative high field MEL in the Alq3 system. Our results suggest that hole-exciton interaction may be the origin of the negative high field MEL and also, in parallel with this interaction, there is also the more common positive high field process occurring which has been tentatively attributed to electron-exciton interactions. The competition between these different processes decides the final shape of the MEL at high fields.

High-efficiency white organic light-emitting diodes using thermally activated delayed fluorescence

International Nuclear Information System (INIS)

Nishide, Jun-ichi; Hiraga, Yasuhide; Nakanotani, Hajime; Adachi, Chihaya

2014-01-01

White organic light-emitting diodes (WOLEDs) have attracted much attention recently, aimed for next-generation lighting sources because of their high potential to realize high electroluminescence efficiency, flexibility, and low-cost manufacture. Here, we demonstrate high-efficiency WOLED using red, green, and blue thermally activated delayed fluorescence materials as emissive dopants to generate white electroluminescence. The WOLED has a maximum external quantum efficiency of over 17% with Commission Internationale de l'Eclairage coordinates of (0.30, 0.38).

Use of gas mixture electroluminescence for optical data readout from wire chambers

International Nuclear Information System (INIS)

Polyakov, V.A.; Rykalin, V.I.; Tskhadadze, Eh.G.

1988-01-01

The radiation spectra, the values of electroluminescence yield and coefficients of gas amplification of Ar and Ne mixture with inorganic and organic additions in a wire chamber operating under proportional and self-quenching streamer conditions are measured. Maximum light yield: 2x10 7 photons for Ar+acetone+white spirit gas mixture in a proportional regime and 1.1x10 7 photons for Ar+CO 2 + ethyl alcohol+ white spirit in self-quenching streamer regime is obtained. Three methods of optical data readout from the wire chambers are tested. The best results are obtained when spectrum shifting bands and fibers are placed behind the chamber cathode planes

Electroluminescence of a-Si/c-Si heterojunction solar cells after high energy irradiation

Energy Technology Data Exchange (ETDEWEB)

Ferrara, Manuela

2009-11-24

The crystalline silicon as absorber material will certainly continue to dominate the market for space applications of solar cells. In the contribution under consideration the applicability of a-Si:H/c-Si heterojunction solar cells in space has been tested by the investigation of the cell modification by high energy protons and comparing the results to the degradation of homojunction crystalline silicon reference cells. The investigated solar cells have been irradiated with protons of different energies and doses. For all investigated solar cells the maximum damage happens for an energy of about 1.7 MeV and is mainly due to the decrease of the effective minority carrier diffusion length in the crystalline silicon absorber. Simulations carried out by AFORS-HET, a heterojunction simulation program, also confirmed this result. The main degradation mechanism for all types of devices is the monotonically decreasing charge carrier diffusion length in the p-type monocrystalline silicon absorber layer. For the heterojunction solar cell an enhancement of the photocurrent in the blue wavelength region has been observed but only in the case of heterojunction solar cell with intrinsic a-Si:H buffer layer. Additionally to the traditional characterization techniques the electroluminescence technique used for monitoring the modifications of the heteroluminescence technique used for monitoring the modifications of the heterointerface between amorphous silicon and crystalline silicon in solar cells after proton irradiation. A direct relation between minority carrier diffusion length and electroluminescence quantum efficiency has been observed but also details of the interface modification could be monitored by this technique.

Study of various n-type organic semiconductors on ultraviolet detective and electroluminescent properties of optoelectronic integrated device

Science.gov (United States)

Deng, Chaoxu; Shao, Bingyao; Zhao, Dan; Zhou, Dianli; Yu, Junsheng

2017-11-01

Organic optoelectronic integrated device (OID) with both ultraviolet (UV) detective and electroluminescent (EL) properties was fabricated by using a thermally activated delayed fluorescence (TADF) semiconductor of (4s, 6s)-2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) as an emitter. The effect of five kinds of n-type organic semiconductors (OSCs) on the enhancement of UV detective and EL properties of OID was systematically studied. The result shows that two orders of magnitude in UV detectivity from 109 to 1011 Jones and 3.3 folds of luminance from 2499 to 8233 cd m-2 could be achieved. The result shows that not only the difference of lowest unoccupied molecular orbital (LUMO) between active layer and OSC but also the variety of electron mobility have a significant effect on the UV detective and EL performance through adjusting electron injection/transport. Additionally, the optimized OSC thickness is beneficial to confine the leaking of holes from the active layer to cathode, leading to the decrease of dark current for high detective performance. This work provides a useful method on broadening OSC material selection and device architecture construction for the realization of high performance OID.

VANGL2 interacts with integrin αv to regulate matrix metalloproteinase activity and cell adhesion to the extracellular matrix.

Science.gov (United States)

Jessen, Tammy N; Jessen, Jason R

2017-12-15

Planar cell polarity (PCP) proteins are implicated in a variety of morphogenetic processes including embryonic cell migration and potentially cancer progression. During zebrafish gastrulation, the transmembrane protein Vang-like 2 (VANGL2) is required for PCP and directed cell migration. These cell behaviors occur in the context of a fibrillar extracellular matrix (ECM). While it is thought that interactions with the ECM regulate cell migration, it is unclear how PCP proteins such as VANGL2 influence these events. Using an in vitro cell culture model system, we previously showed that human VANGL2 negatively regulates membrane type-1 matrix metalloproteinase (MMP14) and activation of secreted matrix metalloproteinase 2 (MMP2). Here, we investigated the functional relationship between VANGL2, integrin αvβ3, and MMP2 activation. We provide evidence that VANGL2 regulates cell surface integrin αvβ3 expression and adhesion to fibronectin, laminin, and vitronectin. Inhibition of MMP14/MMP2 activity suppressed the cell adhesion defect in VANGL2 knockdown cells. Furthermore, our data show that MMP14 and integrin αv are required for increased proteolysis by VANGL2 knockdown cells. Lastly, we have identified integrin αvβ3 as a novel VANGL2 binding partner. Together, these findings begin to dissect the molecular underpinnings of how VANGL2 regulates MMP activity and cell adhesion to the ECM. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Platelet activation by extracellular matrix proteins in haemostasis and thrombosis.

Science.gov (United States)

Watson, Steve P

2009-01-01

The prevention of excessive blood loss to avoid fatal haemorrhage is a pivotal process for all organisms possessing a circulatory system. Increased circulating blood volume and pressure, as required in larger animals, make this process all the more important and challenging. It is essential to have a powerful and rapid system to detect damage and generate an effective seal, and which is also exquisitely regulated to prevent unwanted, excessive or systemic activation so as to avoid blockage of vessels. Thus, a highly specialised and efficient haemostatic system has evolved that consists of cellular (platelets) and protein (coagulation factors) components. Importantly, this is able to support haemostasis in both the low shear environment of the venous system and the high shear environment of the arterial system. Endothelial cells, lining the entire circulation system, play a crucial role in the delicate balance between activation and inhibition of the haemostatic system. An intact and healthy endothelium supports blood flow by preventing attachment of cells and proteins which is required for initiation of coagulation and platelet activation. Endothelial cells produce and release the two powerful soluble inhibitors of platelet activation, nitric oxide and prostacyclin, and express high levels of CD39 which rapidly metabolises the major platelet feedback agonist, ADP. This antithrombotic environment however can rapidly change following activation or removal of endothelial cells through injury or rupture of atherosclerotic plaques. Loss of endothelial cells exposes the subendothelial extracellular matrix which creates strong signals for activation of the haemostatic system including powerful platelet adhesion and activation. Quantitative and qualitative changes in the composition of the subendothelial extracellular matrix influence these prothrombotic characteristics with life threatening thrombotic and bleeding complications, as illustrated by formation of

Conversion Matrix Analysis of GaAs HEMT Active Gilbert Cell Mixers

DEFF Research Database (Denmark)

Jiang, Chenhui; Johansen, Tom Keinicke; Krozer, Viktor

2006-01-01

In this paper, the nonlinear model of the GaAs HEMT active Gilbert cell mixer is investigated. Based on the model, the conversion gain expression of active Gilbert cell mixers is derived theoretically by using conversion matrix analysis method. The expression is verified by harmonic balance simul...

PANI Branches onto Donor-Acceptor Copolymers: Synthesis, Characterization and Electroluminescent Properties of New 2D-Materials

Directory of Open Access Journals (Sweden)

Ignacio A. Jessop

2018-05-01

Full Text Available A new series of two-dimensional statistical conjugated polymers based on aniline and 9,9-dihexylfluorene as donor units and benzo- or naphtho-quinoxaline/thiadiazole derivatives as acceptor moieties, possessing PANI segments as side chains, were designed and synthesized. To investigate the effects of the perpendicular PANI branches on the properties of the main chain, the optical, electrochemical, morphological and electroluminescence properties were studied. The 2D materials tend to possess lower molecular weights and to absorb and to emit light red-shifted compared to the trunk 1D-polymers, in the yellow-red region of the visible spectrum. The 1D- and 2D-conjugated polymers present optical band gaps ranging from 2.15–2.55 eV, HOMO energy levels between −5.37 and −5.60 eV and LUMO energy levels between −3.02 and −3.29 eV. OLED devices based on these copolymers were fabricated. Although the performances were far from optimal due to the high turn-on voltages for which electroluminescence phenomena occur, a maximum luminescence of 55,100 cd/m2 together with a current density of 65 mA/cm2 at 18.5 V were recorded for a 2D-copolymer, PAFC6TBQ-PANI.

Spectroscopic investigation of the interfaces in new poly(9,9-dihexyl–9H-fluorene-2,7- diyl based electroluminescent devices

Directory of Open Access Journals (Sweden)

C. Donitsi

2014-01-01

Full Text Available The highest occupied and lowest unoccupied states of the new electroluminescent material poly(9,9-dihexyl–9H- fluorene-2,7-diyl (PPV-D and polyvinylcarbazole (PVK are investigated using ultraviolet photoelectron and inverse photoemission spectroscopies. Hole injection barriers are determined for interfaces between indium-tin oxide covered substrates with work function ranging from 4.4 to 4.7 eV and these two polymers. Vacuum level alignment with flat bands away from the interface is found when the interface hole barrier is 0.6 eV or larger. Band bending away from the Fermi level occurs when the hole barrier is smaller than 0.6 eV. This is due to the accumulation charges at the interface with the polymer when the injection barrier is small. The resulting field bends the polymer levels to limit charge incoming in the bulk of the film. The efficiency of the electroluminescent structures is strongly influenced by the different energy levels alignment at the layer interfaces.

Preparation and characterizations of electroluminescent p-ZnO : N/n-ZnO : Ga/ITO thin films by spray pyrolysis method

Directory of Open Access Journals (Sweden)

C. Panatarani

2016-02-01

Full Text Available ZnO thin films were fabricated by spray pyrolysis (SP method with p-ZnO : N/n-ZnO:Ga/ITO structure. The X-ray results show that the deposited films have hexagonal wurtzite structure. The EDS results observed that the composition of Ga in ZnO:Ga and N in ZnO:N was 3.73% and 27.73% respectively. The photoluminescence (PL with excitation wave length of 260 nm shows that ZnO:Ga and ZnO:N films emitted UV emission at ∼393 and ∼388 nm, respectively and the films resistivity was 7.12 and 12.80 Ohm-cm respectively. The electroluminescence of the p-ZnO : N/n-ZnO:Ga/ITO structure was obtained by applying forward bias of 5 volt with 30 mA current, resulting in a 3.35 volt threshold bias with the peak electroluminescence in UV-blue range.

White-electroluminescent device with horizontally patterned blue/yellow phosphor-layer structure

International Nuclear Information System (INIS)

Won Park, Boo; Sik Choi, Nam; Won Park, Kwang; Mo Son, So; Kim, Jong Su; Kyun Shon, Pong

2007-01-01

White-electroluminescent (EL) devices with stripe-patterned and square-patterned phosphor-layer structures are fabricated through a screen printing method: electrode/BaTiO 3 insulator layer/patterned blue ZnS:Cu, Cl and yellow ZnS:Cu, Mn phosphor layer/ITO PET substrate. The luminous intensities of EL devices with stripe-patterned and square-patterned phosphor-layer structures are 33% and 23% higher than a conventional device with the phosphor-layer structure without any patterns using the phosphor blend. It can be explained in terms of the absorption of the emitted blue light of blue phosphor layer by the yellow-emitting phosphor layer. The EL device of our patterned phosphor-layer structure gives the possibility to enhance the luminance

JTEC panel on display technologies in Japan

Science.gov (United States)

Tannas, Lawrence E., Jr.; Glenn, William E.; Credelle, Thomas; Doane, J. William; Firester, Arthur H.; Thompson, Malcolm

1992-01-01

This report is one in a series of reports that describes research and development efforts in Japan in the area of display technologies. The following are included in this report: flat panel displays (technical findings, liquid crystal display development and production, large flat panel displays (FPD's), electroluminescent displays and plasma panels, infrastructure in Japan's FPD industry, market and projected sales, and new a-Si active matrix liquid crystal display (AMLCD) factory); materials for flat panel displays (liquid crystal materials, and light-emissive display materials); manufacturing and infrastructure of active matrix liquid crystal displays (manufacturing logistics and equipment); passive matrix liquid crystal displays (LCD basics, twisted nematics LCD's, supertwisted nematic LCD's, ferroelectric LCD's, and a comparison of passive matrix LCD technology); active matrix technology (basic active matrix technology, investment environment, amorphous silicon, polysilicon, and commercial products and prototypes); and projection displays (comparison of Japanese and U.S. display research, and technical evaluation of work).

Hole-exciton interaction induced high field decay of magneto-electroluminescence in Alq{sub 3}-based organic light-emitting diodes at room temperature

Energy Technology Data Exchange (ETDEWEB)

Zhang, Tingting; Holford, D. F.; Gu, Hang; Kreouzis, T. [Materials Research Institute and School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Zhang, Sijie, E-mail: Sijie.zhang@scu.edu.cn, E-mail: w.gillin@qmul.ac.uk [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Gillin, W. P., E-mail: Sijie.zhang@scu.edu.cn, E-mail: w.gillin@qmul.ac.uk [Materials Research Institute and School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China)

2016-01-11

The magnetic field effects on the electroluminescence of aluminium tris-(8-hydroxyqinoline) (Alq{sub 3}) based organic light emitting diodes have been investigated by varying the electron/hole ratio in the emissive layer. Experimental results reveal that a negative high field effect in the magneto-electroluminescence (MEL) can be found in devices with very low triplet exciton concentration at room temperature. This suggests triplet-triplet annihilation cannot be used to explain the negative high field MEL in the Alq{sub 3} system. Our results suggest that hole-exciton interaction may be the origin of the negative high field MEL and also, in parallel with this interaction, there is also the more common positive high field process occurring which has been tentatively attributed to electron-exciton interactions. The competition between these different processes decides the final shape of the MEL at high fields.

Flexible electroluminescent device with inkjet-printed carbon nanotube electrodes

Science.gov (United States)

Azoubel, Suzanna; Shemesh, Shay; Magdassi, Shlomo

2012-08-01

Carbon nanotube (CNTs) inks may provide an effective route for producing flexible electronic devices by digital printing. In this paper we report on the formulation of highly concentrated aqueous CNT inks and demonstrate the fabrication of flexible electroluminescent (EL) devices by inkjet printing combined with wet coating. We also report, for the first time, on the formation of flexible EL devices in which all the electrodes are formed by inkjet printing of low-cost multi-walled carbon nanotubes (MWCNTs). Several flexible EL devices were fabricated by using different materials for the production of back and counter electrodes: ITO/MWCNT and MWCNT/MWCNT. Transparent electrodes were obtained either by coating a thin layer of the CNTs or by inkjet printing a grid which is composed of empty cells surrounded by MWCNTs. It was found that the conductivity and transparency of the electrodes are mainly controlled by the MWCNT film thickness, and that the dominant factor in the luminance intensity is the transparency of the electrode.

Kinetics of transient electroluminescence in organic light emitting diodes

Science.gov (United States)

Shukla, Manju; Kumar, Pankaj; Chand, Suresh; Brahme, Nameeta; Kher, R. S.; Khokhar, M. S. K.

2008-08-01

Mathematical simulation on the rise and decay kinetics of transient electroluminescence (EL) in organic light emitting diodes (OLEDs) is presented. The transient EL is studied with respect to a step voltage pulse. While rising, for lower values of time, the EL intensity shows a quadratic dependence on (t - tdel), where tdel is the time delay observed in the onset of EL, and finally attains saturation at a sufficiently large time. When the applied voltage is switched off, the initial EL decay shows an exponential dependence on (t - tdec), where tdec is the time when the voltage is switched off. The simulated results are compared with the transient EL performance of a bilayer OLED based on small molecular bis(2-methyl 8-hydroxyquinoline)(triphenyl siloxy) aluminium (SAlq). Transient EL studies have been carried out at different voltage pulse amplitudes. The simulated results show good agreement with experimental data. Using these simulated results the lifetime of the excitons in SAlq has also been calculated.

Kinetics of transient electroluminescence in organic light emitting diodes

International Nuclear Information System (INIS)

Shukla, Manju; Brahme, Nameeta; Kumar, Pankaj; Chand, Suresh; Kher, R S; Khokhar, M S K

2008-01-01

Mathematical simulation on the rise and decay kinetics of transient electroluminescence (EL) in organic light emitting diodes (OLEDs) is presented. The transient EL is studied with respect to a step voltage pulse. While rising, for lower values of time, the EL intensity shows a quadratic dependence on (t - t del ), where t del is the time delay observed in the onset of EL, and finally attains saturation at a sufficiently large time. When the applied voltage is switched off, the initial EL decay shows an exponential dependence on (t - t dec ), where t dec is the time when the voltage is switched off. The simulated results are compared with the transient EL performance of a bilayer OLED based on small molecular bis(2-methyl 8-hydroxyquinoline)(triphenyl siloxy) aluminium (SAlq). Transient EL studies have been carried out at different voltage pulse amplitudes. The simulated results show good agreement with experimental data. Using these simulated results the lifetime of the excitons in SAlq has also been calculated

An inorganic electroluminescent device using calcium phosphate doped with Eu{sup 3+} as the luminescent layer

Energy Technology Data Exchange (ETDEWEB)

Koide, Takuhiro [Department of Chemistry and Chemical Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa-shi, Yamagata 992-8510 (Japan); Ito, Michimasa [Tokai Rika Co. Ltd., 3-260 Toyota, Oguchi-cho, Niwa-gun, Aichi 480-0195 (Japan); Kawai, Takahiro [Department of Biochemical Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa-shi, Yamagata 992-8510 (Japan); Matsushima, Yuta, E-mail: ymatsush@yz.yamagata-u.ac.jp [Department of Chemistry and Chemical Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa-shi, Yamagata 992-8510 (Japan)

2013-03-20

Highlights: ► A thin film electroluminescent device was fabricated with a calcium phosphate as the light emitting layer. ► The light emitting layer was formed on the BaTiO{sub 3} disk by a spray pyrolysis method. ► Among the examined calcium phosphates, β-Ca{sub 3}(PO{sub 4}){sub 2}:Eu{sup 3+} showed the best photo- and electroluminescent properties. -- Abstract: In this work, the availability of calcium phosphates for the light emitting layer of a thin-film electroluminescent (TFEL) device was investigated. The goal of this work was to develop an electronic device with ordinary materials such as a calcium phosphate, the principal ingredient of the skeleton of the vertebrate. Compositions of 2CaO·P{sub 2}O{sub 5} (Ca{sub 2}P{sub 2}O{sub 7}), 3CaO·P{sub 2}O{sub 5} (Ca{sub 3}(PO{sub 4}){sub 2}) and 4CaO·P{sub 2}O{sub 5} (Ca{sub 4}O(PO{sub 4}){sub 2}) were examined as the candidates for the light emitting layer. Before composing the TFEL device, the photoluminescence (PL) properties of the three compositions were investigated in the powder form to evaluate the performance as the light emitting layer. Among the examined calcium phosphates, Eu-doped β-Ca{sub 3}(PO{sub 4}){sub 2} showed the best PL properties. It showed typical red-emission from Eu{sup 3+}. The PL intensity was enhanced with the heat-treatment temperature and the optimal temperature was 1250 °C. Then, a TFEL device was prepared by a spray pyrolysis method with the β-Ca{sub 3}(PO{sub 4}){sub 2}:Eu{sup 3+} phosphor layer on a BaTiO{sub 3} disk. The TFEL device exhibited the red emission originating in Eu{sup 3+} at 610 nm under applying alternating voltage. Different from the power sample, the intensity of EL decreased with the heat-treatment temperature from 1000 to 1250 °C. The deterioration of EL at the higher temperatures was attributed to chemical interaction between the phosphor layer and the BaTiO{sub 3} disk.

Electroluminescence analysis of injection-enhanced annealing of electron irradiation-induced defects in GaInP top cells for triple-junction solar cells

Energy Technology Data Exchange (ETDEWEB)

Yi, Tiancheng; Lu, Ming; Yang, Kui; Xiao, Pengfei; Wang, Rong, E-mail: wangr@bnu.edu.cn

2014-09-15

Direct injection-enhanced annealing of defects in a GaInP top cell for GaInP/GaAs/Ge triple-junction solar cells irradiated with 1.8 MeV electrons with a fluence of 1 × 10{sup 15} cm{sup −2} has been observed and analyzed using electroluminescence (EL) spectra. Minority-carrier injection under forward bias conditions is observed to enhance defect annealing in the GaInP top cell, and recovery of the EL intensity of the GaInP top cell was observed even at room temperature. Moreover, the injection-enhanced defect annealing rates obey a simple Arrhenius law; therefore, the annealing activation energy was determined and is equal to 0.51 eV. Lastly, the H2 defect has been identified as the primary non-radiative recombination center based on a comparison of the annealing activation energies.

EMMPRIN mediates beta-adrenergic receptor-stimulated matrix metalloproteinase activity in cardiac myocytes.

OpenAIRE

Siwik Deborah A; Kuster Gabriela M; Brahmbhatt Jamin V; Zaidi Zaheer; Malik Julia; Ooi Henry; Ghorayeb Ghassan

2008-01-01

Extracellular matrix metalloproteinase inducer (EMMPRIN) expression is increased in myocardium from patients with dilated cardiomyopathy and animal models of heart failure. However little is known about the regulated expression or functional role of EMMPRIN in the myocardium. In rat cardiac cells EMMPRIN is expressed on myocytes but not endothelial cells or fibroblasts. Therefore we tested the hypothesis that EMMPRIN expression regulates matrix metalloproteinase (MMP) activity in rat ventricu...

Fabrication and performance of ACTFEL display devices using manganese-doped zinc germanate as a green-emitting electroluminescent layer

International Nuclear Information System (INIS)

Kim, Joo Han; Yoon, Kyung Ho

2010-01-01

Alternating-current thin-film electroluminescent (ACTFEL) display devices fabricated using manganese-doped zinc germanate (Zn 2 GeO 4 :Mn) as a green-emitting electroluminescent layer material are described. The ACTFEL display devices were fabricated with a standard bottom emission structure having a multilayer stack of thin films in the metal/semiconductor/insulator/ metal (MSIM) configuration. The device was constructed on a transparent Corning glass substrate through which the emitted EL light passed. The Zn 2 GeO 4 :Mn emission layer was synthesized by using a RF magnetron sputter deposition method, followed by post-annealing at 700 .deg. C in air ambient for 1 hour. The obtained Zn 2 GeO 4 :Mn films were found to be polycrystalline with a rhombohedral crystal structure. A green emission spectrum with a maximum at approximately 538 nm was produced from the fabricated device. The chromaticity color coordinates of the EL emission were measured to be x = 0.308 and y = 0.657. The device demonstrated a sharp increase in the intensity of green EL emission upon increasing the AC peak voltage applied to the device above a threshold of 148 V.

Localized Surface Plasmon-Enhanced Electroluminescence in OLEDs by Self-Assembly Ag Nanoparticle Film

Science.gov (United States)

He, Xiaoxiao; Wang, Wenjun; Li, Shuhong; Wang, Qingru; Zheng, Wanquan; Shi, Qiang; Liu, Yunlong

2015-12-01

We fabricated Ag nanoparticle (NP) film in organic light emission diodes (OLEDs), and a 23 times increase in electroluminescence (EL) at 518 nm was probed by time-resolved EL measurement. The luminance and relative external quantum efficiency (REQE) were increased by 5.4 and 3.7 times, respectively. There comes a new energy transport way that localized surface plasmons (LSPs) would absorb energy that corresponds to the electron-hole pair before recombination, promoting the formation of electron-hole pair and exciting local surface plasmon resonance (LSPR). The extended lifetime of Alq3 indicates the existence of strong interaction between LSPR and exciton, which decreases the nonradiative decay rate of OLEDs.

Visible-light electroluminescence in Mn-doped GaAs light-emitting diodes

International Nuclear Information System (INIS)

Nam Hai, Pham; Maruo, Daiki; Tanaka, Masaaki

2014-01-01

We observed visible-light electroluminescence (EL) due to d-d transitions in light-emitting diodes with Mn-doped GaAs layers (here, referred to as GaAs:Mn). Besides the band-gap emission of GaAs, the EL spectra show two peaks at 1.89 eV and 2.16 eV, which are exactly the same as 4 A 2 ( 4 F) → 4 T 1 ( 4 G) and 4 T 1 ( 4 G) → 6 A 1 ( 6 S) transitions of Mn atoms doped in ZnS. The temperature dependence and the current-density dependence are consistent with the characteristics of d-d transitions. We explain the observed EL spectra by the p-d hybridized orbitals of the Mn d electrons in GaAs

Exciplex formation and electroluminescent absorption in ultraviolet organic light-emitting diodes

International Nuclear Information System (INIS)

Zhang Qi; Zhang Hao; Xu Tao; Wei Bin; Zhang Xiao-Wen

2015-01-01

We investigated the formation of exciplex and electroluminescent absorption in ultraviolet organic light-emitting diodes (UV OLEDs) using different heterojunction structures. It is found that an energy barrier of over 0.3 eV between the emissive layer (EML) and adjacent transport layer facilitates exciplex formation. The electron blocking layer effectively confines electrons in the EML, which contributes to pure UV emission and enhances efficiency. The change in EML thickness generates tunable UV emission from 376 nm to 406 nm. In addition, the UV emission excites low-energy organic function layers and produces photoluminescent emission. In UV OLED, avoiding the exciplex formation and averting light absorption can effectively improve the purity and efficiency. A maximum external quantum efficiency of 1.2% with a UV emission peak of 376 nm is realized. (paper)

Matrix metalloproteinases (MMP) and cathepsin K contribute differently to osteoclastic activities

DEFF Research Database (Denmark)

Delaissé, Jean-Marie; Andersen, Thomas L; Engsig, Michael T

2003-01-01

The best established proteolytic event of osteoclasts is bone matrix solubilization by the cysteine proteinase cathepsin K. Here, however, we draw the attention on osteoclastic activities depending on matrix metalloproteinases (MMPs). We discuss the observations supporting that MMPs contribute...... significantly to bone matrix solubilization in specific areas of the skeleton and in some developmental and pathological situations. Our discussion takes into account (1) the characteristics of the bone remodeling persisting in the absence of cathepsin K, (2) the ultrastructure of the resorption zone...... in response to inactivation of MMPs and of cathepsin K in different bone types, (3) bone resorption levels in MMP knockout mice compared to wild-type mice, (4) the identification of MMPs in osteoclasts and surrounding cells, and (5) the effect of different bone pathologies on the serum concentrations...

Low-threshold pure UV electroluminescence from n-ZnO:Al/i-layer/n-GaN heterojunction

International Nuclear Information System (INIS)

Li Songzhan; Fang Guojia; Long Hao; Wang Haoning; Huang Huihui; Mo Xiaoming; Zhao Xingzhong

2012-01-01

Ultraviolet (UV) electroluminescence (EL) of n-ZnO:Al (AZO)/i-layer/n-GaN heterojunctions with different intrinsic layers has been obtained. Rectifying behavior and EL spectra of the heterojunctions are investigated at room temperature. Under positive voltage, a dominant UV emission peak around ∼370 nm is observed for both AZO/i-ZnO/n-GaN and AZO/i-MgO/n-GaN heterojunctions. Nevertheless, the UV emission peak intensity of AZO/i-MgO/n-GaN heterojunction is much stronger than that of AZO/i-ZnO/n-GaN heterojunction at the same voltage. The threshold voltage of AZO/i-MgO/n-GaN heterostructured device is as low as 2.3 V. The difference of EL spectra and the emission mechanism in these devices are discussed. - Highlights: ► UV electroluminescence of n-ZnO:Al/i-layer/n-GaN heterojunctions has been obtained. ► Under positive voltage, a dominant UV emission peak around ∼370 nm is observed for both heterojunctions. ► The UV emission peak intensity of the heterojunction with i-MgO layer is much stronger than that with i-ZnO layer at the same voltage. ► The threshold voltage of n-ZnO:Al/i-MgO/n-GaN heterostructured device is as low as 2.3 V.

Analysis of Enzymatic Activity of Matrix Metalloproteinase (MMP) by Collagen Zymography in Melanoma.

Science.gov (United States)

Walia, Vijay; Samuels, Yardena

2018-01-01

Protein zymography is the most commonly used technique to study the enzymatic activity of matrix metalloproteinases (MMPs) and their inhibitors. MMPs are proteolytic enzymes that promote extracellular matrix degradation. MMPs are frequently mutated in malignant melanomas as well as other cancers and are linked to increasing incidence of tumor metastasis. Substrate zymography characterizes MMP activity by their ability to degrade preferred substrates. Here we describe the collagen zymography technique to measure the active or latent form of MMPs using MMP-8 as an example, which is a frequently mutated MMP family member in malignant melanomas. The same technique can be used with the modification of substrate to detect metalloproteinase activity of other MMPs. Both wild-type and mutated forms of MMPs can be analyzed using a single gel using this method.

The nature of trapping sites and recombination centres in PVK and PVK-PBD electroluminescent matrices seen by spectrally resolved thermoluminescence

International Nuclear Information System (INIS)

Glowacki, Ireneusz; Szamel, Zbigniew

2010-01-01

Two electroluminescent polymer matrices poly(N-vinylcarbazole) (PVK) and PVK with 40 wt% of 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD) were studied using spectrally resolved thermoluminescence (SRTL) in the temperature range 15-325 K. The comparison of the SRTL results with the electroluminescence (EL) spectra has allowed identification of the localized (trapping) sites and the radiative recombination centres present in the investigated matrices. In the neat PVK films deep traps with a depth about 200 meV, related to triplet excimers dominate, while in the PVK-PBD (40 wt%) blend films the traps that are related to triplet exciplexes formed by the carbazole groups and the PBD molecules dominate. Depth of the traps in the PVK-PBD blend is somewhat lower than that in the neat PVK. An analysis of the EL spectra shows that in the PVK and in the PVK-PBD blend the dominant radiative centres are singlet excimers and singlet exciplexes, respectively. However, in the neat PVK some contributions of the triplet monomer and the triplet excimer states in the EL were also detected.

Understanding the Relationship between Red Wine Matrix, Tannin Activity, and Sensory Properties.

Science.gov (United States)

Watrelot, Aude A; Byrnes, Nadia K; Heymann, Hildegarde; Kennedy, James A

2016-11-30

One major red wine mouthfeel characteristic, astringency, is derived from grape-extracted tannins and is considered to be a result of interaction with salivary proteins and the oral mucosa. To improve our understanding of the role that the enthalpy of interaction of tannin with a hydrophobic surface (tannin activity) has in astringency perception, a chromatographic method was used to determine the tannin concentration and activity of 34 Cabernet Sauvignon wines, as well as sensory analysis done on 13 of those wines. In addition, astringency-relevant matrix parameters (pH, titratable acidity, ethanol, glucose, and fructose) were measured across all wines. Tannin activity was not significantly correlated with any matrix variables, and the perception of drying and grippy was not correlated with tannin concentration and activity. However, ethanol content was well related to mouthfeel attributes and appeared to drive perceived drying. Although fructose and glucose content were well correlated, they did not drive the perception of sweetness, which is explained by the well-known mixture suppression effect.

Bi-layered nanocomposite bandages for controlling microbial infections and overproduction of matrix metalloproteinase activity.

Science.gov (United States)

Anjana, J; Mohandas, Annapoorna; Seethalakshmy, S; Suresh, Maneesha K; Menon, Riju; Biswas, Raja; Jayakumar, R

2018-04-15

Chronic diabetic wounds is characterised by increased microbial contamination and overproduction of matrix metalloproteases that would degrade the extracellular matrix. A bi-layer bandage was developed, that promotes the inhibition of microbial infections and matrix metalloprotease (MMPs) activity. Bi-layer bandage containing benzalkonium chloride loaded gelatin nanoparticles (BZK GNPs) in chitosan-Hyaluronic acid (HA) as a bottom layer and sodium alendronate containing chitosan as top layer was developed. We hypothesized that the chitosan-gelatin top layer with sodium alendronate could inhibit the MMPs activity, whereas the chitosan-HA bottom layer with BZK GNPs (240±66nm) would enable the elimination of microbes. The porosity, swelling and degradation nature of the prepared Bi-layered bandage was studied. The bottom layer could degrade within 4days whereas the top layer remained upto 7days. The antimicrobial activity of the BZK NPs loaded bandage was determined using normal and clinical strains. Gelatin zymography shows that the proteolytic activity of MMP was inhibited by the bandage. Copyright © 2017 Elsevier B.V. All rights reserved.

ZnO nanorod based low turn-on voltage LEDs with wide electroluminescence spectra

International Nuclear Information System (INIS)

Jha, S.K.; Kutsay, O.; Bello, I.; Lee, S.T.

2013-01-01

Light emitting diodes (LEDs) based on arrays of n-type ZnO Nanorods were fabricated on p-GaN films using a hydrothermal method. The LEDs emit mainly in blue and UV range of the light. Their current–Voltage (I–V) characteristics typically show a low leakage current (7.2 μA) and a high rectification ratio (3 5 5). Devices operate at a low turn-on voltage of ∼4.5 V. Photoluminescence (PL) and electroluminescence (EL) measurements suggest low density of ZnO defects; however, in some aspects density of interfacial defects still might be considerable in the studied devices. The PL emission is deconvoluted to three peaks that are located at wavelengths of 361, 381, and 397 nm, while the wide EL spectra are deconvoluted to five peaks appearing at 368, 385, 427, 474, and 515 nm. Near-band-edge (NBE) emission of p-GaN and n-ZnO was observed in both the PL and EL spectra. Deconvoluted EL spectra consist of a very wide green band with the peak at 515 nm and extending up to 650 nm (red), and a rarely reported EL emission at 474 nm. Origin of these emissions is discussed, herein. The electrical characteristics together with EL characteristics indicate potential to develop and study p-GaN/n-ZnO nanorod LEDs for white emitting applications. - Highlights: ► A low turn-on voltage (4–4.5 V) and low threshold (5 V) electroluminescence from ZnO/GaN heterostructure. ► A wide spectrum EL emission (360–700 nm) suitable for white LED application. ► EL spectra consist of a rarely reported emission band with peak at 474 nm. ► Low-temperature and solution based fabrication, which is scalable and of low cost.

Direct current electroluminescence in rare-earth-doped zinc sulphide

International Nuclear Information System (INIS)

Bryant, F.J.; Krier, A.

1984-01-01

Some of the properties and characteristics of rare-earth-doped zinc sulphide DCEL devices are reported. Two types of devices are discussed, co-evaporated ZnS:RE thin films and ion implanted ZnS:RE single crystal diodes. The thin film devices exhibit bright DCEL of various colours at low applied voltages (typically approximately 12 V). A study of the spectral intensities and lifetimes of the Er 3+ ion in ZnS:Er 3+ thin films is consistent with a Boltzmann energy distribution amongst the conduction electrons present in these devices. The ZnS:RE single crystal diodes fabricated in this laboratory by ion implantation are also capable of various colour DCEL. By comparing the EL emission obtained from the different rare earth dopants, erbium and neodymium are identified as the most efficient luminescence centres. Further consideration of the EL emission spectra gives evidence for the presence of inter-conduction band hot electron transitions in those devices containing rare earth dopants which are inefficent electroluminescence centres. These findings can be explained in terms of Auger processes occurring in rare earth complexes. (author)

Virtually pure near-infrared electroluminescence from exciplexes at polyfluorene/hexaazatrinaphthylene interfaces

Energy Technology Data Exchange (ETDEWEB)

Tregnago, G.; Fléchon, C.; Cacialli, F., E-mail: amateo@polymat.eu, E-mail: f.cacialli@ucl.ac.uk [Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT (United Kingdom); Choudhary, S. [School of Soft Matter Research, Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs-Universität Freiburg, Albertstraße 19, 79104 Freiburg (Germany); Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104 Freiburg (Germany); Gozalvez, C. [POLYMAT, University of the Basque Country UPV/EHU, Avenida de Tolosa 72, E-20018 Donostia-San Sebastian (Spain); Mateo-Alonso, A., E-mail: amateo@polymat.eu, E-mail: f.cacialli@ucl.ac.uk [POLYMAT, University of the Basque Country UPV/EHU, Avenida de Tolosa 72, E-20018 Donostia-San Sebastian (Spain); Ikerbasque, Basque Foundation for Science, Bilbao (Spain)

2014-10-06

Electronic processes at the heterojunction between chemically different organic semiconductors are of special significance for devices such as light-emitting diodes (LEDs) and photovoltaic diodes. Here, we report the formation of an exciplex state at the heterojunction of an electron-transporting material, a functionalized hexaazatrinaphthylene, and a hole-transporting material, poly(9,9-dioctylfluorene-alt-N-(4-butylphenyl)diphenylamine) (TFB). The energetics of the exciplex state leads to a spectral shift of ∼1 eV between the exciton and the exciplex peak energies (at 2.58 eV and 1.58 eV, respectively). LEDs incorporating such bulk heterojunctions display complete quenching of the exciton luminescence, and a nearly pure near-infrared electroluminescence arising from the exciplex (at ∼1.52 eV) with >98% of the emission at wavelengths above 700 nm at any operational voltage.

Virtually pure near-infrared electroluminescence from exciplexes at polyfluorene/hexaazatrinaphthylene interfaces

International Nuclear Information System (INIS)

Tregnago, G.; Fléchon, C.; Cacialli, F.; Choudhary, S.; Gozalvez, C.; Mateo-Alonso, A.

2014-01-01

Electronic processes at the heterojunction between chemically different organic semiconductors are of special significance for devices such as light-emitting diodes (LEDs) and photovoltaic diodes. Here, we report the formation of an exciplex state at the heterojunction of an electron-transporting material, a functionalized hexaazatrinaphthylene, and a hole-transporting material, poly(9,9-dioctylfluorene-alt-N-(4-butylphenyl)diphenylamine) (TFB). The energetics of the exciplex state leads to a spectral shift of ∼1 eV between the exciton and the exciplex peak energies (at 2.58 eV and 1.58 eV, respectively). LEDs incorporating such bulk heterojunctions display complete quenching of the exciton luminescence, and a nearly pure near-infrared electroluminescence arising from the exciplex (at ∼1.52 eV) with >98% of the emission at wavelengths above 700 nm at any operational voltage.

Virtually pure near-infrared electroluminescence from exciplexes at polyfluorene/hexaazatrinaphthylene interfaces

Science.gov (United States)

Tregnago, G.; Fléchon, C.; Choudhary, S.; Gozalvez, C.; Mateo-Alonso, A.; Cacialli, F.

2014-10-01

Electronic processes at the heterojunction between chemically different organic semiconductors are of special significance for devices such as light-emitting diodes (LEDs) and photovoltaic diodes. Here, we report the formation of an exciplex state at the heterojunction of an electron-transporting material, a functionalized hexaazatrinaphthylene, and a hole-transporting material, poly(9,9-dioctylfluorene-alt-N-(4-butylphenyl)diphenylamine) (TFB). The energetics of the exciplex state leads to a spectral shift of ˜1 eV between the exciton and the exciplex peak energies (at 2.58 eV and 1.58 eV, respectively). LEDs incorporating such bulk heterojunctions display complete quenching of the exciton luminescence, and a nearly pure near-infrared electroluminescence arising from the exciplex (at ˜1.52 eV) with >98% of the emission at wavelengths above 700 nm at any operational voltage.

Pulsed Electrical Spin Injection into InGaAs Quantum Dots: Studies of the Electroluminescence Polarization Dynamics

International Nuclear Information System (INIS)

Asshoff, P.; Loeffler, W.; Fluegge, H.; Zimmer, J.; Mueller, J.; Westenfelder, B.; Hu, D. Z.; Schaadt, D. M.; Kalt, H.; Hetterich, M.

2010-01-01

We present time-resolved studies of the spin polarization dynamics during and after initialization through pulsed electrical spin injection into InGaAs quantum dots embedded in a p-i-n-type spin-injection light-emitting diode. Experiments are performed with pulse widths in the nanosecond range and a time-resolved single photon counting setup is used to detect the subsequent electroluminescence. We find evidence that the achieved spin polarization shows an unexpected temporal behavior, attributed mainly to many-carrier and non-equilibrium effects in the device.

Blue-light-emitting organic electroluminescence via exciplex emission based on a fluorene derivative

International Nuclear Information System (INIS)

Li Fushan; Chen Zhijian; Wei Wei; Cao Huayu; Gong Qihuang; Teng Feng; Qian Lei; Wang Yuanmin

2004-01-01

The synthesis of a high photoluminescence efficiency (88%, compared with tris(8-hydroxyquinoline)(Alq 3 )) organic material 9,9-Dibutyl-N,N,N,N-tetraphenyl-9H-fluorene-2,7-diamine (DTFD) via Ullmann condensation was reported. Exiciplex emission of the ITO/DTFD/2,2-[1,2-phenylenebis(oxy)]bis(N,N-diphenylacetamide)/Alq 3 /LiF/Al device was observed and the peak wavelength of the emission was measured to be 480 nm, which belongs to the blue region. A turn-on voltage as low as 4 V and maximal brightness as large as 400 cd m -2 were measured. The electroluminescence spectrum was observed to be blue-shifted with increase in applied voltage

Blue-light-emitting organic electroluminescence via exciplex emission based on a fluorene derivative

Energy Technology Data Exchange (ETDEWEB)

Li Fushan [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Chen Zhijian [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Wei Wei [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Cao Huayu [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Gong Qihuang [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Teng Feng [Institute of Optoelectronic Technology, Northern Jiaotong University, Beijing 100044 (China); Qian Lei [Institute of Optoelectronic Technology, Northern Jiaotong University, Beijing 100044 (China); Wang Yuanmin [Institute of Optoelectronic Technology, Northern Jiaotong University, Beijing 100044 (China)

2004-06-21

The synthesis of a high photoluminescence efficiency (88%, compared with tris(8-hydroxyquinoline)(Alq{sub 3})) organic material 9,9-Dibutyl-N,N,N,N-tetraphenyl-9H-fluorene-2,7-diamine (DTFD) via Ullmann condensation was reported. Exiciplex emission of the ITO/DTFD/2,2-[1,2-phenylenebis(oxy)]bis(N,N-diphenylacetamide)/Alq{sub 3}/LiF/Al device was observed and the peak wavelength of the emission was measured to be 480 nm, which belongs to the blue region. A turn-on voltage as low as 4 V and maximal brightness as large as 400 cd m{sup -2} were measured. The electroluminescence spectrum was observed to be blue-shifted with increase in applied voltage.

Plastic Substrate Active Matrix Displays Final Report CRADA No. TC-2011-00

Energy Technology Data Exchange (ETDEWEB)

Bernhardt, A. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Smith, P. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-09-28

This project was a collaborative effort between the University of California, Lawrence Livermore National Laboratory (LLNL) and FlexICs, Inc. to develop thin film transistor (TFT) electronics for active matrix displays.

High performance organic integrated device with ultraviolet photodetective and electroluminescent properties consisting of a charge-transfer-featured naphthalimide derivative

Energy Technology Data Exchange (ETDEWEB)

Wang, Hanyu; Wang, Xu; Yu, Junsheng, E-mail: luzhiyun@scu.edu.cn, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhou, Jie; Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn, E-mail: jsyu@uestc.edu.cn [College of Chemistry, Sichuan University, Chengdu 610064 (China)

2014-08-11

A high performance organic integrated device (OID) with ultraviolet photodetective and electroluminescent (EL) properties was fabricated by using a charge-transfer-featured naphthalimide derivative of 6-(3,5-bis-[9-(4-t-butylphenyl)-9H-carbazol-3-yl]-phenoxy)-2- (4-t-butylphenyl)-benzo[de]isoquinoline-1,3-dione (CzPhONI) as the active layer. The results showed that the OID had a high detectivity of 1.5 × 10{sup 11} Jones at −3 V under the UV-350 nm illumination with an intensity of 0.6 mW/cm{sup 2}, and yielded an exciplex EL light emission with a maximum brightness of 1437 cd/m{sup 2}. Based on the energy band diagram, both the charge transfer feature of CzPhONI and matched energy level alignment were responsible for the dual ultraviolet photodetective and EL functions of OID.

Peptide-Based Selective Inhibitors of Matrix Metalloproteinase-Mediated Activities

Directory of Open Access Journals (Sweden)

Margaret W. Ndinguri

2012-11-01

Full Text Available The matrix metalloproteinases (MMPs exhibit a broad array of activities, some catalytic and some non-catalytic in nature. An overall lack of selectivity has rendered small molecule, active site targeted MMP inhibitors problematic in execution. Inhibitors that favor few or individual members of the MMP family often take advantage of interactions outside the enzyme active site. We presently focus on peptide-based MMP inhibitors and probes that do not incorporate conventional Zn2+ binding groups. In some cases, these inhibitors and probes function by binding only secondary binding sites (exosites, while others bind both exosites and the active site. A myriad of MMP mediated-activities beyond selective catalysis can be inhibited by peptides, particularly cell adhesion, proliferation, motility, and invasion. Selective MMP binding peptides comprise highly customizable, unique imaging agents. Areas of needed improvement for MMP targeting peptides include binding affinity and stability.

Thermo-optical properties of 1H[3,4-b] quinoline films used in electroluminescent devices

Science.gov (United States)

Jaglarz, Janusz; Kępińska, Mirosława; Sanetra, Jerzy

2014-06-01

Electroluminescence cells with H[3,4-b] quinoline layers are promising devices for a blue light emitting EL diode. This work measured the optical reflectance as a function of temperature in copolymers PAQ layers deposited on Si crystalline substrate. Using the extended Cauchy dispersion model of the film refractive index we determined the thermo-optical coefficients for quinoline layers in the temperature range of 76-333 K from combined ellipsometric and spectrofotometric studies. The obtained values of thermo-optical coefficients of thin PAQ film, were negative and ranged in 5-10 × 10-4 [1/K].

Photo- and electro-luminescence of rare earth doped ZnO electroluminors at liquid nitrogen temperature

International Nuclear Information System (INIS)

Bhushan, S.; Kaza, B.R.; Pandey, A.N.

1981-01-01

Photo (PL) and electroluminescent (EL) spectra of some rare earth (La, Gd, Er or Dy) doped ZnO electroluminors have been investigated at liquid nitrogen temperature (LNT) and compared with their corresponding results at room temperature (RT). In addition to three bands observed at RT, one more band on the higher wavelength side appears in EL spectra. Spectral shift with the exciting intensity at LNT supports the donor-acceptor (DA) model in which the rare earths form the donor levels. From the temperature dependent studies of PL and EL brightness, the EL phenomenon is found to be more susceptible to traps. (author)

Study on the visibility of an electroluminescent display for automobiles; Jidoshayo EL display no shininsei

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, N; Harada, M; Idogaki, T [Denso Corp., Aichi (Japan)

1997-10-01

This report explores the visibility of an Electroluminescent (EL) display for automotive use. Displays for automobiles are exposed to the direct rays of the sun and forced to operate in wide temperature range. Therefore, luminous flux density by the lighting on EL display panel and operating environment temperature must be considered for the visibility evaluation. Sensory evaluation on the visibility and physical measurements such as contrast, chromaticity difference in accordance with the viewing angle change indicate that the visibility of the EL display for automobiles is advantageous over other displays. 6 refs., 11 figs., 1 tab.

On the influence of matrix's heterogeneity on uncertainty of gamma-spectrometry at activity assay of radioactive waste

Directory of Open Access Journals (Sweden)

V. S. Prokopenko

2009-09-01

Full Text Available The influence of the waste matrix heterogeneity on the flux density value of initial gamma quanta at the transport of quanta in the matrix was considered. It is shown that the waste heterogeneity leads to the positive shift of the average flux density value comparing with corresponding value for homogeneous waste if average value of the attenuation factor in heterogeneous matrix is equal to the attenuation factor of homogeneous matrix. Due to this the activity assay of heterogeneous waste by a technique which was calibrated by using a homogeneous standard (surrogate container the measurement results will be positively shifted, or, in other words, conservative estimation of the waste activity will be obtained.

Differential in vivo zymography: a method for observing matrix metalloproteinase activity in the zebrafish embryo.

Science.gov (United States)

Keow, Jonathan Y; Herrmann, Kurt M; Crawford, Bryan D

2011-04-01

Investigations into the molecular mechanisms of, and cellular signaling pathways modulating ECM remodeling are especially challenging due to the complex post-translational regulation of the primary effectors of ECM catabolism - the matrix metalloproteinases (MMPs). Recently a variety of approaches to the detection of MMP activity have been developed, and the prospect of visualizing ECM remodeling activity in living tissues is now opening exciting avenues of research for matrix biologists. In particular the use of FRET-quenched MMP substrates, which generate a fluorescent signal upon hydrolysis, is becoming increasingly popular, especially because linkers with defined and/or restricted proteolytic sensitivity can be used to bind fluorophore-quencher pairs, making these probes useful in characterizing the activity of specific proteases. We have taken advantage of the transparency and amenability to reverse genetics of the zebrafish embryo, in combination with these fluorogenic MMP substrates, to develop a multiplex in vivo assay for MMP activity that we dub "differential in vivo zymography." Copyright © 2011 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

Ramiprilate inhibits functional matrix metalloproteinase activity in Crohn's disease fistulas

DEFF Research Database (Denmark)

Efsen, Eva; Saermark, Torben; Hansen, Alastair

2011-01-01

Increased expression of matrix metalloproteinase (MMP)-2, -3 and -9 has been demonstrated in Crohn's disease fistulas, but it is unknown whether these enzymes are biologically active and represent a therapeutic target. Therefore, we investigated the proteolytic activity of MMPs in fistula tissue...... from six controls were also included. Total functional MMP activity was measured by a high-pressure liquid chromatography (HPLC)-based, fluorogenic MMP-substrate cleavage assay, and the specific activity of MMP-2, -3 and -9 by the MMP Biotrak Activity Assay. The MMP inhibitors comprised ethylene......-9.83) compared with non-Crohn's fistulas, [0.32 ng/ml, range 0-2.66, (p MMP-9 activity [0.64 ng/ml, range 0-5.66 and 0.17 ng/ml, range 0-1.1, respectively (p MMP activity level by 42% and suppressed the specific MMP-3...

Risk matrix model applied to the outsourcing of logistics' activities

Directory of Open Access Journals (Sweden)

Fouad Jawab

2015-09-01

Full Text Available Purpose: This paper proposes the application of the risk matrix model in the field of logistics outsourcing. Such an application can serve as the basis for decision making regarding the conduct of a risk management in the logistics outsourcing process and allow its prevention. Design/methodology/approach: This study is based on the risk management of logistics outsourcing in the field of the retail sector in Morocco. The authors identify all possible risks and then classify and prioritize them using the Risk Matrix Model. Finally, we have come to four possible decisions for the identified risks. The analysis was made possible through interviews and discussions with the heads of departments and agents who are directly involved in each outsourced activity. Findings and Originality/value: It is possible to improve the risk matrix model by proposing more personalized prevention measures according to each company that operates in the mass-market retailing. Originality/value: This study is the only one made in the process of logistics outsourcing in the retail sector in Morocco through Label’vie as a case study. First, we had identified as thorough as we could all possible risks, then we applied the Risk Matrix Model to sort them out in an ascending order of importance and criticality. As a result, we could hand out to the decision-makers the mapping for an effective control of risks and a better guiding of the process of risk management.

On the origin of excimer emission in electroluminescence and photoluminescence spectra of polyfluorenes

International Nuclear Information System (INIS)

Vacha, Martin; Ha, Jaekook; Sato, Hisaya

2007-01-01

We report a study on the differences in red-shifted excimer band in photoluminescence (PL) and electroluminescence (EL) spectra of thin films of a copolymer of dibutylfluorene and butylphenylphenoxazine. The relative intensity of the excimer band in PL spectra increases with temperature above the polymer glass transition, and with the intensity of the excitation light. In EL spectra, on the other hand, the relative excimer intensity is seen to decrease with increasing driving voltage. These opposite trends originate from the different nature of excitations in PL and EL spectra: photoexcitation directly creates singlet excitons while electric excitation proceeds via interaction of injected electrons and holes. In case of electric excitation, the observed results might be due to trap-assisted excimer formation

Influence of gamma-irradiation on the electroluminescence of ZnSe:Zn,Te crystals

International Nuclear Information System (INIS)

Elmuratova, D.B.; Ibragimova, E.M.

2007-01-01

Effect of 60 Co gamma-radiation at the dose rate of 10 Gy/s on electroluminescence (El)Zn Se crystals with 0.5 weight % Te treated in zinc vapor was studied for possible manufacturing of light emitting structures. Broad El band with the maximum at 610 nm is excited in the origin samples at a voltage above 15 V. After irradiation to the high dose of 10 6 Gy the El intensity grows by ∼2.5 times in the direct polarity at 24 V. The observed El of Zn Se:Zn,Te single crystals is assumed to be caused by the charge carrier recombination at the interstitial zinc centers by the excitation mechanism of a barrier sub breakdown type (authors)

AMP-Activated Protein Kinase Alleviates Extracellular Matrix Accumulation in High Glucose-Induced Renal Fibroblasts through mTOR Signaling Pathway

Directory of Open Access Journals (Sweden)

Xia Luo

2015-01-01

Full Text Available Background/Aims: Extracellular matrix accumulation contributes significantly to the pathogenesis of diabetic nephropathy. Although AMP-activated protein kinase (AMPK has been found to inhibit extracellular matrix synthesis by experiments in vivo and vitro, its role in alleviating the deposition of extracellular matrix in renal interstitial fibroblasts has not been well defined. Methods: Currently, we conducted this study to investigate the effects of AMPK on high glucose-induced extracellular matrix synthesis and involved intracellular signaling pathway by using western blot in the kidney fibroblast cell line (NRK-49f. Results: Collagen IV protein levels were significantly increased by high glucose in a time-dependent manner. This was associated with a decrease in Thr72 phosphorylation of AMPK and an increase in phosphorylation of mTOR on Ser2448. High glucose-induced extracellular matrix accumulation and mTOR activation were significantly inhibited by the co-treatment of rAAV-AMPKα1312 (encoding constitutively active AMPKα1 whereas activated by r-AAV-AMPKα1D157A (encoding dominant negative AMPKα1. In cultured renal fibroblasts, overexpression of AMPKα1D157A upregulated mTOR signaling and matrix synthesis, which were ameliorated by co-treatment with the inhibitor of mTOR, rapamycin. Conclusion: Collectively, these findings indicate that AMPK exerts renoprotective effects by inhibiting the accumulation of extracellular matrix through mTOR signaling pathway.

Poly[(arylene ethynylene)-alt-(arylene vinylene)]s based on anthanthrone and its derivatives: synthesis and photophysical, electrochemical, electroluminescent, and photovoltaic properties

Czech Academy of Sciences Publication Activity Database

John, S. V.; Cimrová, Věra; Ulbricht, C.; Pokorná, Veronika; Růžička, Aleš; Giguére, J.-B.; Lafleur-Lambert, A.; Morin, J.-F.; Iwuoha, E.; Egbe, D. A. M.

2017-01-01

Roč. 50, č. 21 (2017), s. 8357-8371 ISSN 0024-9297 R&D Projects: GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : polycyclic aromatic compounds * anthanthrones and anthanthrone derivatives * electroluminescence Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 5.835, year: 2016

Excitation spectra and forward injection electroluminescence of Er/sup 3+/ ions in ZnS

International Nuclear Information System (INIS)

Jiaqi, Y.; Tianren, Z.; Wenlian, L.

1985-01-01

Trivalent rare earth ions (RE/sup 3+/) are efficient luminescent centers for electroluminescence (EL) of thin films of II-VI compounds, which are promising display materials and attract more and more attention. The mechanism of all EL devices of RE/sup 3+/ available so far is hot electron impact excitation. Based on the analysis of excitation spectra of RE/sup 3+/ in ZnS, the authors have pointed out the possibility of a new type of EL of RE/sup 3+/ - forward injection EL, which have potential of reducing operation voltage and raising efficiency. The forward injection EL of RE/sup 3+/ has been observed and experimentally proven in ZnS:Er/sup 3+/ diode for the first time

High performance yellow organic electroluminescent devices by doping iridium(III) complex into host materials with stepwise energy levels

Energy Technology Data Exchange (ETDEWEB)

Cui, Rongzhen; Zhou, Liang, E-mail: zhoul@ciac.ac.cn; Jiang, Yunlong; Li, Yanan; Zhao, Xuesen; Zhang, Hongjie, E-mail: hongjie@ciac.ac.cn

2015-10-15

In this work, we aim to further improve the electroluminescent (EL) performances of a yellow light-emitting iridium(III) complex by designing double light-emitting layers (EMLs) devices having stepwise energy levels. Compared with single-EML devices, these designed double-EML devices showed improved EL efficiency and brightness attributed to better balance in carriers. In addition, the stepwise distribution in energy levels of host materials is instrumental in broadening the recombination zone, thus delaying the roll-off of EL efficiency. Based on the investigation of carriers' distribution, device structure was further optimized by adjusting the thickness of deposited layers. Finally, yellow EL device (Commission Internationale de l'Eclairage (CIE) coordinates of (0.446, 0.542)) with maximum current efficiency, power efficiency and brightness up to 78.62 cd/A (external quantum efficiency (EQE) of 21.1%), 82.28 lm/W and 72,713 cd/m{sup 2}, respectively, was obtained. Even at the high brightness of 1000 cd/m{sup 2}, EL efficiency as high as 65.54 cd/A (EQE=17.6%) can be retained. - Highlights: • Yellow electroluminescent devices were designed and fabricated. • P-type and n-type materials having stepwise energy levels were chosen as host materials. • Better balance of holes and electrons causes the enhanced efficiencies. • Improved carriers' trapping suppresses the emission of host material.

Improvement of the matrix effect compensation in active neutron measurement by simulated annealing algorithm (June 2009)

International Nuclear Information System (INIS)

Raoux, A. C.; Loridon, J.; Mariani, A.; Passard, C.

2009-01-01

Active neutron measurements such as the Differential Die-Away (DDA) technique involving pulsed neutron generator, are widely applied to determine the fissile content of waste packages. Unfortunately, the main drawback of such techniques is coming from the lack of knowledge of the waste matrix composition. Thus, the matrix effect correction for the DDA measurement is an essential improvement in the field of fissile material content determination. Different solutions have been developed to compensate the effect of the matrix on the neutron measurement interpretation. In this context, this paper describes an innovative matrix correction method we have developed with the goal of increasing the accuracy of the matrix effect correction and reducing the measurement time. The implementation of this method is based on the analysis of the raw signal with an optimisation algorithm called the simulated annealing algorithm. This algorithm needs a reference data base of Multi-Channel Scaling (MCS) spectra, to fit the raw signal. The construction of the MCS library involves a learning phase to define and acquire the DDA signals. This database has been provided by a set of active signals from experimental matrices (mock-up waste drums of 118 litres) recorded in a specific device dedicated to neutron measurement research and development of the Nuclear Measurement Laboratory of CEA-Cadarache, called PROMETHEE 6. The simulated annealing algorithm is applied to make use of the effect of the matrices on the total active signal of DDA measurement. Furthermore, as this algorithm is directly applied to the raw active signal, it is very useful when active background contributions can not be easily estimated and removed. Most of the cases tested during this work which represents the feasibility phase of the method, are within a 4% agreement interval with the expected experimental value. Moreover, one can notice that without any compensation of the matrix effect, the classical DDA prompt

Improvement of the matrix effect compensation in active neutron measurement by simulated annealing algorithm (June 2009)

Energy Technology Data Exchange (ETDEWEB)

Raoux, A. C.; Loridon, J.; Mariani, A.; Passard, C. [French Atomic Energy Commission, DEN, Cadarache, F-3108 Saint-Paul-Lez-Durance (France)

2009-07-01

Active neutron measurements such as the Differential Die-Away (DDA) technique involving pulsed neutron generator, are widely applied to determine the fissile content of waste packages. Unfortunately, the main drawback of such techniques is coming from the lack of knowledge of the waste matrix composition. Thus, the matrix effect correction for the DDA measurement is an essential improvement in the field of fissile material content determination. Different solutions have been developed to compensate the effect of the matrix on the neutron measurement interpretation. In this context, this paper describes an innovative matrix correction method we have developed with the goal of increasing the accuracy of the matrix effect correction and reducing the measurement time. The implementation of this method is based on the analysis of the raw signal with an optimisation algorithm called the simulated annealing algorithm. This algorithm needs a reference data base of Multi-Channel Scaling (MCS) spectra, to fit the raw signal. The construction of the MCS library involves a learning phase to define and acquire the DDA signals. This database has been provided by a set of active signals from experimental matrices (mock-up waste drums of 118 litres) recorded in a specific device dedicated to neutron measurement research and development of the Nuclear Measurement Laboratory of CEA-Cadarache, called PROMETHEE 6. The simulated annealing algorithm is applied to make use of the effect of the matrices on the total active signal of DDA measurement. Furthermore, as this algorithm is directly applied to the raw active signal, it is very useful when active background contributions can not be easily estimated and removed. Most of the cases tested during this work which represents the feasibility phase of the method, are within a 4% agreement interval with the expected experimental value. Moreover, one can notice that without any compensation of the matrix effect, the classical DDA prompt

DANTE, Activation Analysis Neutron Spectra Unfolding by Covariance Matrix Method

International Nuclear Information System (INIS)

Petilli, M.

1981-01-01

1 - Description of problem or function: The program evaluates activation measurements of reactor neutron spectra and unfolds the results for dosimetry purposes. Different evaluation options are foreseen: absolute or relative fluxes and different iteration algorithms. 2 - Method of solution: A least-square fit method is used. A correlation between available data and their uncertainties has been introduced by means of flux and activity variance-covariance matrices. Cross sections are assumed to be constant, i.e. with variance-covariance matrix equal to zero. The Lagrange multipliers method has been used for calculating the solution. 3 - Restrictions on the complexity of the problem: 9 activation experiments can be analyzed. 75 energy groups are accepted

Exciplex formation and electroluminescent absorption in ultraviolet organic light-emitting diodes

Science.gov (United States)

Zhang, Qi; Zhang, Hao; Zhang, Xiao-Wen; Xu, Tao; Wei, Bin

2015-02-01

We investigated the formation of exciplex and electroluminescent absorption in ultraviolet organic light-emitting diodes (UV OLEDs) using different heterojunction structures. It is found that an energy barrier of over 0.3 eV between the emissive layer (EML) and adjacent transport layer facilitates exciplex formation. The electron blocking layer effectively confines electrons in the EML, which contributes to pure UV emission and enhances efficiency. The change in EML thickness generates tunable UV emission from 376 nm to 406 nm. In addition, the UV emission excites low-energy organic function layers and produces photoluminescent emission. In UV OLED, avoiding the exciplex formation and averting light absorption can effectively improve the purity and efficiency. A maximum external quantum efficiency of 1.2% with a UV emission peak of 376 nm is realized. Project supported by the National Natural Science Foundation of China (Grant Nos. 61136003 and 61275041) and the Guangxi Provincial Natural Science Foundation, China (Grant No. 2012GXNSFBA053168).

Pesticide-exposure Matrix helps identify active ingredients in pesticides used in past years

Science.gov (United States)

Pesticide-exposure Matrix was developed to help epidemiologists and other researchers identify the active ingredients to which people were likely exposed when their homes and gardens were treated for pests in past years

Organic Light-Emitting Diodes Based on Phthalimide Derivatives: Improvement of the Electroluminescence Properties

Directory of Open Access Journals (Sweden)

Frédéric Dumur

2018-03-01

Full Text Available In this study, a phthalimide-based fluorescent material has been examined as a green emitter for multilayered organic light-emitting diodes (OLEDs. By optimizing the device stacking, a maximum brightness of 28,450 cd/m2 at 11.0 V and a maximum external quantum efficiency of 3.11% could be obtained. Interestingly, OLEDs fabricated with Fluo-2 presented a 20-fold current efficiency improvement compared to the previous results reported in the literature, evidencing the crucial role of the device stacking in the electroluminescence (EL performance of a selected emitter. Device lifetime was also examined and an operational stability comparable to that reported for a standard triplet emitter i.e., bis(4-methyl-2,5-diphenyl-pyridineiridium(III acetylacetonate [(mdppy2Iracac] was evidenced.

PPARγ agonist pioglitazone reduces matrix metalloproteinase-9 activity and neuronal damage after focal cerebral ischemia

International Nuclear Information System (INIS)

Lee, Seong-Ryong; Kim, Hahn-Young; Hong, Jung-Suk; Baek, Won-Ki; Park, Jong-Wook

2009-01-01

Pioglitazone, a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, has shown protective effects against ischemic insult in various tissues. Pioglitazone is also reported to reduce matrix metalloproteinase (MMP) activity. MMPs can remodel extracellular matrix components in many pathological conditions. The current study was designed to investigate whether the neuroprotection of pioglitazone is related to its MMP inhibition in focal cerebral ischemia. Mice were subjected to 90 min focal ischemia and reperfusion. In gel zymography, pioglitazone reduced the upregulation of active form of MMP-9 after ischemia. In in situ zymograms, pioglitazone also reduced the gelatinase activity induced by ischemia. After co-incubation with pioglitazone, in situ gelatinase activity was directly reduced. Pioglitazone reduced the infarct volume significantly compared with controls. These results demonstrate that pioglitazone may reduce MMP-9 activity and neuronal damage following focal ischemia. The reduction of MMP-9 activity may have a possible therapeutic effect for the management of brain injury after focal ischemia.

Spontaneous formation of {1 1-bar 0 1} InGaN quantum wells on a (1 1 2-bar 2) GaN template and their electroluminescence characteristics

International Nuclear Information System (INIS)

Masui, Hisashi; Kamber, Derrick S; Brinkley, Stuart E; Wu, Feng; Baker, Troy J; Zhong, Hong; Iza, Michael; Speck, James S; Nakamura, Shuji; DenBaars, Steven P

2010-01-01

Discrete dies of the light-emitting diode (LED) fabricated on a (1 1 2-bar 2)-oriented GaN template exhibited electroluminescence peaked at 467 nm and optical output power was greater than 200 µW at 20 mA. The LED was found to have quantum well structure grown on spontaneously formed {1 1-bar 0 1} facets, confirmed via transmission electron microscopy. Polarization switching was observed in luminescence perpendicular to the device surface: the dominant polarization was parallel to [1-bar 1-bar 2 3]. The device structure was shown to be advantageous for photovoltaic cell applications by evaluating photo-induced current, although piezoelectric effects on photocurrent were not explicitly determined. The filling rate of band-edge states was estimated to be 0.025 eV per decade of current via low-temperature electroluminescence measurements

Neutron activation analysis on determination of arsenic in biological matrixes

International Nuclear Information System (INIS)

Menezes, Maria Angela de B.C.; Silva, Maria Aparecida

2013-01-01

Aiming at giving support to the Worker's Health Awareness Program of the Municipal Department of Health of Belo Horizonte, an assessment related arsenic was carried out in two galvanising factories by means of hair and toenail samples analysis as biomonitors. The arsenic was determined in all matrixes from the factories where gold electrodeposition process was applied. This is because arsenic salts are usually added to gold bath to improve the metal covering. The high concentration results surprised the health surveillance professionals, and alerted for the need of assessing the influence of a long-term exposure. Studies concerning galvanising process have usually been developed broaching many aspects, but so far few works has pointed out the detection and measurement of other elements like arsenic. The k 0 -Instrumental Neutron Activation method was applied confirming to be a suitable technique on determination of arsenic in biological matrixes. (author)

Neutron activation analysis on determination of arsenic in biological matrixes

Energy Technology Data Exchange (ETDEWEB)

Menezes, Maria Angela de B.C.; Silva, Maria Aparecida, E-mail: menezes@cdtn.br, E-mail: cida@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2013-07-01

Aiming at giving support to the Worker's Health Awareness Program of the Municipal Department of Health of Belo Horizonte, an assessment related arsenic was carried out in two galvanising factories by means of hair and toenail samples analysis as biomonitors. The arsenic was determined in all matrixes from the factories where gold electrodeposition process was applied. This is because arsenic salts are usually added to gold bath to improve the metal covering. The high concentration results surprised the health surveillance professionals, and alerted for the need of assessing the influence of a long-term exposure. Studies concerning galvanising process have usually been developed broaching many aspects, but so far few works has pointed out the detection and measurement of other elements like arsenic. The k{sub 0}-Instrumental Neutron Activation method was applied confirming to be a suitable technique on determination of arsenic in biological matrixes. (author)

Activity and expression of urokinase-type plasminogen activator and matrix metalloproteinases in human colorectal cancer

International Nuclear Information System (INIS)

Kim, Tae-Dong; Song, Kyoung-Sub; Li, Ge; Choi, Hoon; Park, Hae-Duck; Lim, Kyu; Hwang, Byung-Doo; Yoon, Wan-Hee

2006-01-01

Matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and urokinase-type plasminogen activator (uPA) are involved in colorectal cancer invasion and metastasis. There is still debate whether the activity of MMP-2 and MMP-9 differs between tumors located in the colon and rectum. We designed this study to determine any differences in the expression of MMP-2, MMP-9 and uPA system between colon and rectal cancer tissues. Cancer tissue samples were obtained from colon carcinoma (n = 12) and rectal carcinomas (n = 10). MMP-2 and MMP-9 levels were examined using gelatin zymography and Western blotting; their endogenous inhibitors, tissue inhibitor of metalloproteinase-2 (TIMP-2) and tissue inhibitor of metalloproteinase-1 (TIMP-1), were assessed by Western blotting. uPA, uPAR and PAI-1 were examined using enzyme-linked immunosorbent assay (ELISA). The activity of uPA was assessed by casein-plasminogen zymography. In both colon and rectal tumors, MMP-2, MMP-9 and TIMP-1 protein levels were higher than in corresponding paired normal mucosa, while TIMP-2 level in tumors was significantly lower than in normal mucosa. The enzyme activities or protein levels of MMP-2, MMP-9 and their endogenous inhibitors did not reach a statistically significant difference between colon and rectal cancer compared with their normal mucosa. In rectal tumors, there was an increased activity of uPA compared with the activity in colon tumors (P = 0.0266), however urokinase-type plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) showed no significant difference between colon and rectal cancer tissues. These findings suggest that uPA may be expressed differentially in colon and rectal cancers, however, the activities or protein levels of MMP-2, MMP-9, TIMP-1, TIMP-2, PAI-1 and uPAR are not affected by tumor location in the colon or the rectum

Liquid crystalline networks for electroluminescent displays

International Nuclear Information System (INIS)

Contoret, A.E.A.

2001-09-01

This work presents the first low molar mass organic electroluminescent (EL) material to form a nematic glass and then emit plane-polarised light from the vitrified state on application of an electric field. Photocrosslinkable molecules are also discussed which form insoluble films on illumination with ultra-violet light. This approach combines the ease of deposition of small molecules with the robustness and stability of polymers, allowing simple fabrication of multi-layer EL devices and photo-patterning. A range of conjugated low molar-mass molecules are considered, containing the anthracene, perylene and fluorene cores, with the aims of producing a general recipe for efficient EL, based on ordered, stable nematics at room temperature. Many physical properties are compared and molecular mechanics modeling is used to represent molecular geometries. An acrylate and several diene photo-polymerisable derivatives of the fluorenes undergo photo-crosslinking. Infrared and photoluminescence spectroscopy is used to examine crosslinking in detail and to optimise exposure conditions. The diene shows no significant degradation for an optimal exposure, but requires a high fluence of 100 Jcm -2 to form an insoluble film. A doped photo-alignment layer is used for the first time to obtain polarised El with ratio 11:1 and 80 cdm -2 brightness from the crosslinked diene. The insoluble crosslinked network allows spin coating of an electron transporting over-layer, resulting in increased brightness. Complex impedance spectroscopy and time of flight measurements confirm good material properties with complete depletion of the crosslinkable diene molecule and non-dispersive conduction. Finally, a novel deposition technique, pulsed laser deposition (PLD), is presented, as an alternative to spin coating or vapour deposition. Minimal degradation is observed for optimised deposition conditions and a PLD film is successfully demonstrated in an EL device. (author)

The effect of DCJTB doping concentration in PVK on the chromatic coordinate of electroluminescence

Energy Technology Data Exchange (ETDEWEB)

Zhang, F J; Xu, Z; Zhao, S L; Wang, L W; Yuan, G C [Key Laboratory of Luminescence and Optical Information (Beijing Jiaotong University), Ministry of Education (China); Zhao, D W [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)], E-mail: fjzhang@bjtu.edu.cn

2008-05-15

The dominant mechanism of electroluminescence (EL) from 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (DCJTB) doped in poly-(N-vinyl-carbazole) (PVK) system was demonstrated to be a charge carrier trapped by DCJTB molecular rather than Foerster energy transfer from PVK to DCJTB. The chromatically coordinate EL emission of PVK:DCJTB changes from (0.41, 0.31) to (0.67, 0.31) with an increase in DCJTB doping concentration. The emission peak in DCJTB shows red-shift and the shoulder emission peak at 656 nm becomes stronger as the doping concentration increases. The effect of DCJTB doping concentration on EL spectra is attributed to strong dipole-dipole interaction between the DCJTB molecule with an increase in doping concentration.

Matrix Metalloproteinase Activities And Some Hormones Levels During Gestation Period In Cows

International Nuclear Information System (INIS)

TEAMA, F.E.

2010-01-01

Many factors including proteases, growth factors and hormones play important role in implantation and tissue remodelling of endometrium during different stages of gestation.Matrix metalloproteinases (MMP) such as gelatinases mainly MMP-2 and MMP-9 are implicated in the degradation of extracellular matrix for tissue remodelling.The aim of the present study is to evaluate the role of matrix metalloproteinases (MMP-2 and MMP-9) and hormones including progesterone (P4) and estradiol (E2) in the gestation process. The enzyme activities of MMP-2 and MMP-9 in serum collected from 8 Brown Swiss cows during different periods of gestation using zymography technique were examined. Hormonal levels for both P4 and E2 were determined using radioimmunoassay and also total proteins were estimated. A significant increase in MMP-2 activity by about 98%, 115% and 110% in the 1 st , 2 nd and 3 rd trimester of gestation were recorded, respectively, whereas it increased to be 185% in the pre-partum period as compared to non-pregnant cows (P nd trimester was recorded where the activity elevated by about 85% of non-pregnant controls (P st and 3 rd trimesters, the enzyme activity was not detectable. P4 level was increased gradually until its maximum at the 2 nd trimester then decreased until pre-partum.E2 level recorded too little increase at the beginning of the 1 st and 2 nd trimesters then sharply increased at the 3 rd one reached its maximum at pre-partum. There were significant decreases in total protein concentrations in the 2 nd and 3 rd trimesters then reached the lowest level before parturition .It could be concluded that the high activity of MMP-2 but not MMP-9 enzyme has important role throughout the gestation period in cows and P4 has important role in the fetal growth and E2 in the placental loss.

Magneto-electroluminescence effects in the single-layer organic light-emitting devices with macrocyclic aromatic hydrocarbons

Directory of Open Access Journals (Sweden)

S.-T. Pham

2018-02-01

Full Text Available Magneto-electroluminescence (MEL effects are observed in single-layer organic light-emitting devices (OLEDs comprising only macrocyclic aromatic hydrocarbons (MAHs. The fluorescence devices were prepared using synthesized MAHs, namely, [n]cyclo-meta-phenylene ([n]CMP, n = 5, 6. The MEL ratio of the resulting OLED is 1%–2% in the spectral wavelength range of 400-500 nm, whereas it becomes negative (−1.5% to −2% in the range from 650 to 700 nm. The possible physical origins of the sign change in the MEL are discussed. This wavelength-dependent sign change in the MEL ratio could be a unique function for future single-layer OLEDs capable of magnetic-field-induced color changes.

Magneto-electroluminescence effects in the single-layer organic light-emitting devices with macrocyclic aromatic hydrocarbons

Science.gov (United States)

Pham, S.-T.; Ikemoto, K.; Suzuki, K. Z.; Izumi, T.; Taka, H.; Kita, H.; Sato, S.; Isobe, H.; Mizukami, S.

2018-02-01

Magneto-electroluminescence (MEL) effects are observed in single-layer organic light-emitting devices (OLEDs) comprising only macrocyclic aromatic hydrocarbons (MAHs). The fluorescence devices were prepared using synthesized MAHs, namely, [n]cyclo-meta-phenylene ([n]CMP, n = 5, 6). The MEL ratio of the resulting OLED is 1%-2% in the spectral wavelength range of 400-500 nm, whereas it becomes negative (-1.5% to -2%) in the range from 650 to 700 nm. The possible physical origins of the sign change in the MEL are discussed. This wavelength-dependent sign change in the MEL ratio could be a unique function for future single-layer OLEDs capable of magnetic-field-induced color changes.

Electroluminescence of a polythiophene molecular wire suspended between a metallic surface and the tip of a scanning tunneling microscope.

Science.gov (United States)

Reecht, Gaël; Scheurer, Fabrice; Speisser, Virginie; Dappe, Yannick J; Mathevet, Fabrice; Schull, Guillaume

2014-01-31

The electroluminescence of a polythiophene wire suspended between a metallic surface and the tip of a scanning tunneling microscope is reported. Under positive sample voltage, the spectral and voltage dependencies of the emitted light are consistent with the fluorescence of the wire junction mediated by localized plasmons. This emission is strongly attenuated for the opposite polarity. Both emission mechanism and polarity dependence are similar to what occurs in organic light emitting diodes (OLED) but at the level of a single molecular wire.

Pattern visual evoked potentials elicited by organic electroluminescence screen.

Science.gov (United States)

Matsumoto, Celso Soiti; Shinoda, Kei; Matsumoto, Harue; Funada, Hideaki; Sasaki, Kakeru; Minoda, Haruka; Iwata, Takeshi; Mizota, Atsushi

2014-01-01

To determine whether organic electroluminescence (OLED) screens can be used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs). Checkerboard patterns were generated on a conventional cathode-ray tube (S710, Compaq Computer Co., USA) screen and on an OLED (17 inches, 320 × 230 mm, PVM-1741, Sony, Tokyo, Japan) screen. The time course of the luminance changes of each monitor was measured with a photodiode. The p-VEPs elicited by these two screens were recorded from 15 eyes of 9 healthy volunteers (22.0 ± 0.8 years). The OLED screen had a constant time delay from the onset of the trigger signal to the start of the luminescence change. The delay during the reversal phase from black to white for the pattern was 1.0 msec on the cathode-ray tube (CRT) screen and 0.5 msec on the OLED screen. No significant differences in the amplitudes of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by the CRT and the OLED screens. The OLED screen can be used as a visual stimulator to elicit p-VEPs; however the time delay and the specific properties in the luminance change must be taken into account.

Physical processes in thin-film electroluminescent structures based on ZnS:Mn showing self-organized patterns

International Nuclear Information System (INIS)

Zuccaro, S.; Raker, Th.; Niedernostheide, F.-J.; Kuhn, T.; Purwins, H.-G.

2003-01-01

Physical processes in thin ZnS:Mn films and their relation to the formation of dynamical patterns in the electroluminescence of AC driven films are investigated. The technique of photo-depolarization-spectroscopy is used to investigate defect states in these films and it is shown that specific features in the spectra correlate with the observed self-organized patterns. Furthermore, the time dependence of the dissipative current is measured at the same samples and compared with current waveforms obtained from numerical simulations of a drift-diffusion model. The results are used to discuss the origin of the self-organized processes in ZnS:Mn-films

An electroluminescence device for printable electronics using coprecipitated ZnS:Mn nanocrystal ink

International Nuclear Information System (INIS)

Toyama, T; Hama, T; Adachi, D; Nakashizu, Y; Okamoto, H

2009-01-01

Electroluminescence (EL) devices for printable electronics using coprecipitated ZnS:Mn nanocrystal (NC) ink are demonstrated. The EL properties of these devices were investigated along with the structural and optical properties of ZnS:Mn NCs with an emphasis on their dependence on crystal size. Transmission electron microscopy and x-ray diffraction studies revealed that the NCs, with a crystal size of 3-4 nm, are nearly monodisperse; the crystal size can be controlled by the Zn 2+ concentration in the starting solution for coprecipitation. The results of optical studies indicate the presence of quantum confinement effects; in addition, the NC surfaces are well passivated, regardless of the crystal size. Finally, an increase in the luminance of EL devices with a decrease in crystal size is observed, which suggests the excitation mechanism of ZnS:Mn NC EL devices.

Electroluminescent refrigeration by ultra-efficient GaAs light-emitting diodes

Science.gov (United States)

Patrick Xiao, T.; Chen, Kaifeng; Santhanam, Parthiban; Fan, Shanhui; Yablonovitch, Eli

2018-05-01

Electroluminescence—the conversion of electrons to photons in a light-emitting diode (LED)—can be used as a mechanism for refrigeration, provided that the LED has an exceptionally high quantum efficiency. We investigate the practical limits of present optoelectronic technology for cooling applications by optimizing a GaAs/GaInP double heterostructure LED. We develop a model of the design based on the physics of detailed balance and the methods of statistical ray optics, and predict an external luminescence efficiency of ηext = 97.7% at 263 K. To enhance the cooling coefficient of performance, we pair the refrigerated LED with a photovoltaic cell, which partially recovers the emitted optical energy as electricity. For applications near room temperature and moderate power densities (1.0-10 mW/cm2), we project that an electroluminescent refrigerator can operate with up to 1.7× the coefficient of performance of thermoelectric coolers with ZT = 1, using the material quality in existing GaAs devices. We also predict superior cooling efficiency for cryogenic applications relative to both thermoelectric and laser cooling. Large improvements to these results are possible with optoelectronic devices that asymptotically approach unity luminescence efficiency.

Simple synthesis, photophysics, and electroluminescent properties of poly[2,7-bis(4-tert-butylstyryl)fluorene-9,9-diyl-alt-alkane-.alpha.,.omega.-diyl

Czech Academy of Sciences Publication Activity Database

Mikroyannidis, J. A.; Barberis, V. P.; Výprachtický, Drahomír; Cimrová, Věra

2007-01-01

Roč. 45, č. 5 (2007), s. 809-821 ISSN 0887-624X R&D Projects: GA MŠk(CZ) 1M06031; GA AV ČR IAA4050409; GA ČR GA203/04/1372 Institutional research plan: CEZ:AV0Z40500505 Keywords : distyrylfluorene * electrochemical properties * electroluminescence Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.529, year: 2007

Blue and green electroluminescence from CdSe nanocrystal quantum-dot-quantum-wells

International Nuclear Information System (INIS)

Lu, Y. F.; Cao, X. A.

2014-01-01

CdS/CdSe/ZnS quantum dot quantum well (QDQW) nanocrystals were synthesized using the successive ion layer adsorption and reaction technique, and their optical properties were tuned by bandgap and strain engineering. 3-monolayer (ML) CdSe QWs emitted blue photoluminescence at 467 nm with a spectral full-width-at-half-maximum of ∼30 nm. With a 3 ML ZnS cladding layer, which also acts as a passivating and strain-compensating layer, the QDQWs acquired a ∼35% quantum yield of the QW emission. Blue and green electroluminescence (EL) was obtained from QDQW light-emitting devices with 3–4.5 ML CdSe QWs. It was found that as the peak blueshifted, the overall EL was increasingly dominated by defect state emission due to poor hole injection into the QDQWs. The weak EL was also attributed to strong field-induced charge separation resulting from the unique QDQW geometry, weakening the oscillator strength of optical transitions

High matrix metalloproteinase activity is a hallmark of periapical granulomas.

Science.gov (United States)

de Paula-Silva, Francisco Wanderley Garcia; D'Silva, Nisha J; da Silva, Léa Assed Bezerra; Kapila, Yvonne Lorraine

2009-09-01

The inability to distinguish periapical cysts from granulomas before performing root canal treatment leads to uncertainty in treatment outcomes because cysts have lower healing rates. Searching for differential expression of molecules within cysts or granulomas could provide information with regard to the identity of the lesion or suggest mechanistic differences that may form the basis for future therapeutic intervention. Thus, we investigated whether granulomas and cysts exhibit differential expression of extracellular matrix (ECM) molecules. Human periapical granulomas, periapical cysts, and healthy periodontal ligament tissues were used to investigate the differential expression of ECM molecules by microarray analysis. Because matrix metalloproteinases (MMP) showed the highest differential expression in the microarray analysis, MMPs were further examined by in situ zymography and immunohistochemistry. Data were analyzed by using one-way analysis of variance followed by the Tukey test. We observed that cysts and granulomas differentially expressed several ECM molecules, especially those from the MMP family. Compared with cysts, granulomas exhibited higher MMP enzymatic activity in areas stained for MMP-9. These areas were composed of polymorphonuclear cells (PMNs) in contrast to cysts. Similarly, MMP-13 was expressed by a greater number of cells in granulomas compared with cysts. Our findings indicate that high enzymatic MMP activity in PMNs together with MMP-9 and MMP-13 stained cells could be a molecular signature of granulomas unlike periapical cysts.

Study on electroluminescence processes in dye-doped organic light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Li Weizhi [State Key Laboratory of Electronic Thin Films and Integrated devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)], E-mail: leewz@uestc.edu.cn; Jiang Yadong; Wang Tao [State Key Laboratory of Electronic Thin Films and Integrated devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2008-07-15

Electroluminescence (EL) mechanism of dye-doped organic light-emitting diodes (OLEDs) was investigated by using three familiar fluorescent dyes, i.e., 5,12-Dihydro-5,12-dimethylquino [2,3-b]acridine-7,14-dione (DMQA), 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran(DCJTB), and 5,6,11,12-tetraphenylnaphthacene (Rubrene). EL spectra of the doped devices with structure of indium tin oxide (ITO)/N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'- diamine (NPB) (40 nm)/tris-(8-hydroxyquinolate)-aluminum (Alq{sub 3}) (x nm, x=0-40 nm)/dye: Alq{sub 3} (weight ratio{approx}1%, 2 nm)/Alq{sub 3} (48-x nm)/MgAg indicated that direct carrier trapping (DCT) process dominated light emission of devices. As a result, investigation of carrier-recombination site via doping, which is conventionally applied in OLEDs, is questionable since the doping site and the dopant itself may significantly influence the carrier-recombination process in the doped devices.

Improved luminescence properties of nanocrystalline silicon based electroluminescent device by annealing

International Nuclear Information System (INIS)

Sato, Keisuke; Hirakuri, Kenji

2006-01-01

We report an annealing effect on electrical and luminescence properties of a red electroluminescent device consisting of nanocrystalline silicon (nc-Si). The red luminescence was generated by flowing the forward current into the device at a low threshold direct current (DC) forward voltage with a rise of annealing temperature up to 500 deg. C. Moreover, the luminescence of the device annealed at 500 deg. C was more intense than that of the device annealed at 200 deg. C or less under the same forward current density, because of the injection of a large quantity of carriers to the radiative recombination centers at the nc-Si surface vicinity. These were attained by a low resistivity of indium tin oxide (ITO) electrode and good contact at the ITO electrode/luminous layer interface region by the annealing treatment. The above results indicated that the annealing treatment of the device is effective for the realization of high luminance due to the improvement in the injection efficiency of carriers to the radiative recombination centers

A photovoltaic module diagnostic setup for lock-in-thermography and lock-in electroluminescence imaging

DEFF Research Database (Denmark)

Parikh, Harsh; Spataru, Sergiu; Sera, Dezso

2018-01-01

Electroluminescence (EL) imaging and infrared (IRT) thermography techniques have become indispensable tools in recent years for health diagnostic of PV modules in solar industry application. Complementary to these imaging methods, lock-in techniques can effectively remove noise by periodically...... modulating the input signal and averaging it over a desired number of periods. We propose a combined lock-in EL and lock-in IRT diagnostic setup for accurate analysis of different types of faults occurring in a solar module. The setup is built around a Goldeye CL-033 high-speed SWIR camera, which can acquire...... experimental work on a (36/72) cell solar module using combined (EL) or (IRT) lock-in-thermography. The setup allows one to investigate the different technological problems that can occur when performing PV diagnostics in drone-based inspections....

Homogeneous Synthesis and Electroluminescence Device of Highly Luminescent CsPbBr3 Perovskite Nanocrystals.

Science.gov (United States)

Wei, Song; Yang, Yanchun; Kang, Xiaojiao; Wang, Lan; Huang, Lijian; Pan, Daocheng

2017-03-06

Highly luminescent CsPbBr 3 perovskite nanocrystals (PNCs) are homogeneously synthesized by mixing toluene solutions of PbBr 2 and cesium oleate at room temperature in open air. We found that PbBr 2 can be easily dissolved in nonpolar toluene in the presence of tetraoctylammonium bromide, which allows us to homogeneously prepare CsPbBr 3 perovskite quantum dots and prevents the use of harmful polar organic solvents, such as N,N-dimethylformamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone. Additionally, this method can be extended to synthesize highly luminescent CH 3 NH 3 PbBr 3 perovskite quantum dots. An electroluminescence device with a maximal luminance of 110 cd/m 2 has been fabricated by using high-quality CsPbBr 3 PNCs as the emitting layer.

Correlation between telomerase activity and matrix metalloproteinases 2 expression in gastric cancer.

Science.gov (United States)

Wang, Gang; Wang, Wenling; Zhou, Jianjiang; Yang, Xiaofeng

2013-01-01

To investigate the relationship between telomerase activity (TA) and matrix metallo proteinases 2 (MMP-2) on malignant behavior and prognosis predictable value in gastric cancer. Telomerase activity and MMP-2 protein expressions were tested in 40 gastric surgical resected cancer samples and the clinicopathological data of enrolled patients were obtained to get correlation analysis results. The expression of telomerase was up-regulated with infiltrating depth, lymph node metastasis and stage (P correlated with infiltrating depth (P < 0.05). Combined detections of telomerase activity and MMP2 protein could identify patients at high risk in disease recurrence and prognosis more efficiently.

Cortisol/cortisone ratio and matrix metalloproteinase-9 activity are associated with pediatric primary hypertension.

Science.gov (United States)

Martinez-Aguayo, Alejandro; Campino, Carmen; Baudrand, Rene; Carvajal, Cristian A; García, Hernán; Aglony, Marlene; Bancalari, Rodrigo; García, Lorena; Loureiro, Carolina; Vecchiola, Andrea; Tapia-Castillo, Alejandra; Valdivia, Carolina; Sanhueza, Sebastian; Fuentes, Cristobal A; Lagos, Carlos F; Solari, Sandra; Allende, Fidel; Kalergis, Alexis M; Fardella, Carlos E

2016-09-01

To identify novel biomarkers associated with pediatric primary hypertension. We recruited 350 participants (4-16 years). Anthropometric parameters and aldosterone, plasma renin activity, cortisol, cortisone, Homeostasis Model Assessment Insulin Resistance (HOMA-IR), high-sensitivity C-reactive protein, adiponectin, IL-6, plasminogen activator inhibitor type 1 levels and matrix metalloproteinase-9 and matrix metalloproteinase-2 (MMP-9 and MMP-2) activities were measured. Genomic DNA was isolated. Patients with altered glucose metabolism, severe obesity [BMI-SD score (BMI-SDS) > 2.5], renovascular disease, primary aldosteronism and apparent mineralocorticoid excess syndrome were excluded. In selected participants (n = 320), SBP was positively correlated with BMI-SDS (r = 0.382, P cortisol/cortisone ratio (r = 0.231, P cortisol/cortisone ratio (P cortisol/cortisone ratio (OR = 3.92; 95% CI = 1.98-7.71) and increased MMP-9 activity (OR = 4.23; 95% CI = 2.15-8.32). We report that MMP-9 activity and the cortisol/cortisone ratio were higher in pediatric primary hypertensive patients, and these associations were independent of the effect of obesity. The potential role of these novel biomarkers in predicting hypertension risk and blood pressure regulation warrants further investigation.

Chromosomal loop/nuclear matrix organization of transcriptionally active and inactive RNA polymerases in HeLa nuclei.

Science.gov (United States)

Roberge, M; Dahmus, M E; Bradbury, E M

1988-06-05

The relative distribution of transcriptionally active and inactive RNA polymerases I and II between the nuclear matrix/scaffold and chromosomal loops of HeLa cells was determined. Total RNA polymerase was assessed by immunoblotting and transcribing RNA polymerase by a photoaffinity labeling technique in isolated nuclei. Nuclear matrix/scaffold was isolated by three methods using high-salt, intermediate-salt or low-salt extraction. The distribution of RNA polymerases I and II were very similar within each of the methods, but considerable differences in distributions were found between the different preparation methods. Either intermediate-salt or high-salt treatment of DNase I-digested nuclei showed significant association of RNA polymerases with the nuclear matrix. However, intermediate-salt followed by high-salt treatment released all transcribing and non-transcribing RNA polymerases. Nuclear scaffolds isolated with lithium diiodosalicylate (low-salt) contained very little of the RNA polymerases. This treatment, however, caused the dissociation of RNA polymerase II transcription complexes. These results show unambiguously that RNA polymerases, both in their active and inactive forms, are not nuclear matrix proteins. The data support models in which the transcriptional machinery moves around DNA loops during transcription.

The Exopolysaccharide Matrix

Science.gov (United States)

Koo, H.; Falsetta, M.L.; Klein, M.I.

2013-01-01

Many infectious diseases in humans are caused or exacerbated by biofilms. Dental caries is a prime example of a biofilm-dependent disease, resulting from interactions of microorganisms, host factors, and diet (sugars), which modulate the dynamic formation of biofilms on tooth surfaces. All biofilms have a microbial-derived extracellular matrix as an essential constituent. The exopolysaccharides formed through interactions between sucrose- (and starch-) and Streptococcus mutans-derived exoenzymes present in the pellicle and on microbial surfaces (including non-mutans) provide binding sites for cariogenic and other organisms. The polymers formed in situ enmesh the microorganisms while forming a matrix facilitating the assembly of three-dimensional (3D) multicellular structures that encompass a series of microenvironments and are firmly attached to teeth. The metabolic activity of microbes embedded in this exopolysaccharide-rich and diffusion-limiting matrix leads to acidification of the milieu and, eventually, acid-dissolution of enamel. Here, we discuss recent advances concerning spatio-temporal development of the exopolysaccharide matrix and its essential role in the pathogenesis of dental caries. We focus on how the matrix serves as a 3D scaffold for biofilm assembly while creating spatial heterogeneities and low-pH microenvironments/niches. Further understanding on how the matrix modulates microbial activity and virulence expression could lead to new approaches to control cariogenic biofilms. PMID:24045647

High-performance alternating current field-induced chromatic-stable white polymer electroluminescent devices employing a down-conversion layer

Energy Technology Data Exchange (ETDEWEB)

Xia, Yingdong; Chen, Yonghua; Smith, Gregory M. [Center for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, Winston-Salem, NC 27105 (United States); Sun, Hengda; Yang, Dezhi [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Nie, Wanyi; Li, Yuan; Huang, Wenxiao [Center for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, Winston-Salem, NC 27105 (United States); Ma, Dongge [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Carroll, David L., E-mail: carroldl@wfu.edu [Center for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, Winston-Salem, NC 27105 (United States)

2015-05-15

In this work, a high-performance alternating current (AC) filed-induced chromatic-stable white polymer electroluminescence (WFIPEL) device was fabricated by combining a fluorophor Poly(9,9-dioctylfluorene) (PFO)-based blue device with a yellow down-conversion layer (YAG:Ce). A maximum luminance of this down-conversion FIPEL device achieves 3230 cd m{sup −2}, which is 1.41 times higher than the device without the down-conversion layer. A maximum current efficiency and power efficiency of the down-conversion WFIPEL device reach 19.7 cd A{sup −1} at 3050 cd m{sup −2} and 5.37 lm W{sup −1} at 2310 cd m{sup −2} respectively. To the best of our knowledge, the power efficiency is one of the highest reports for the WFIPEL up to now. Moreover, Commison Internationale de L’Eclairage (CIE) coordinates of (0.28, 0.30) is obtained by adjusting the thickness of the down-conversion layer to 30 μm and it is kept stable over the entire AC-driven voltage range. We believe that this AC-driven, down-conversion, WFIPEL device may offer an easy way towards future flat and flexible lighting sources. - Highlights: • A high-performance AC filed-induced chromatic-stable white polymer electroluminescence (WFIPEL) device was fabricated. • A maximum luminance, current efficiency, and power efficiency achieves 3230 cd m{sup −2}, 19.7 cd A{sup −1}, and 5.37 lm W{sup −1}, respectively. • The power efficiency is one of the highest reports for the WFIPEL up to now. • The EL spectrum kept very stable over the entire AC-driven voltage range.

Investigation of CaTiO3:Pr3+ thin films deposited by radiofrequency reactive magnetron sputtering for electroluminescence application

International Nuclear Information System (INIS)

Sarakha, L; Bousquet, A; Tomasella, E; Boutinaud, P; Mahiou, R

2010-01-01

In this report we successfully deposited thin films of CaTiO 3 :Pr 3+ by radiofrequency magnetron sputtering. The films were studied and we tried to understand the evolution of their optical and electrical properties. We noticed that the annealing temperature and the deposition pressures have an important influence on these properties. Thin films with good optical and electrical properties have been obtained. These films are transparent and are characterized by an intense red photoluminescence and a low fixed charge density. They are well dedicated for electroluminescence purposes.

Two-band superlinear electroluminescence in GaSb based nanoheterostructures with AlSb/InAs.sub.1-x./sub.Sb.sub.x./sub./AlSb deep quantum well

Czech Academy of Sciences Publication Activity Database

Mikhailova, M. P.; Ivanov, E.V.; Danilov, L.V.; Petukhov, A.A.; Kalinina, K.V.; Slobozhanyuk, S.I.; Zegrya, G.G.; Stoyanov, N. D.; Yakovlev, Yu. P.; Hospodková, Alice; Pangrác, Jiří; Oswald, Jiří; Zíková, Markéta; Hulicius, Eduard

2014-01-01

Roč. 115, č. 22 (2014), "223102-1"-"223102-5" ISSN 0021-8979 R&D Projects: GA ČR GA13-15286S Institutional support: RVO:68378271 Keywords : MOVPE * GaSb * InAs * electroluminescence * quantum well Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.183, year: 2014

Ultraviolet electroluminescence from Au/MgO/MgxZn1−xO heterojunction diodes and the observation of Zn-rich cluster emission

International Nuclear Information System (INIS)

Liu, C.Y.; Xu, H.Y.; Sun, Y.; Zhang, C.; Ma, J.G.; Liu, Y.C.

2014-01-01

In this work, ultraviolet (UV) electroluminescence (EL) is achieved from Au/MgO/Mg x Zn 1−x O heterojunction diodes. The EL mechanism and laser forming process are discussed based on the energy band diagram, impact-ionization process and disordered optical structure. For ZnO and low Mg-content MgZnO devices, their EL spectra show single near-band-edge (NBE) emission. While in high Mg-content MgZnO devices, the emission from self-formed Zn-rich MgZnO clusters is observed and also contribute to the UV EL band. These Zn-rich clusters can act as thermally-stable luminescence centers, suggesting a promising route for developing MgZnO-based UV light-emitting devices. -- Highlights: • A series of Au/MgO/Mg x Zn 1−x O heterojunction diodes with multiple Mg compositions are fabricated and ultraviolet electroluminescence is achieved. • EL mechanism and laser forming process are discussed based on energy band diagram, impact-ionization process and disordered optical structure. • The transition from spontaneous to stimulated emission is observed in these heterojunctions, and the lasing mode is random laser. • In high Mg-content MgZnO devices, the emission from self-formed Zn-rich clusters is observed, which are thermally stable luminescence centers

Pattern Visual Evoked Potentials Elicited by Organic Electroluminescence Screen

Directory of Open Access Journals (Sweden)

Celso Soiti Matsumoto

2014-01-01

Full Text Available Purpose. To determine whether organic electroluminescence (OLED screens can be used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs. Method. Checkerboard patterns were generated on a conventional cathode-ray tube (S710, Compaq Computer Co., USA screen and on an OLED (17 inches, 320 × 230 mm, PVM-1741, Sony, Tokyo, Japan screen. The time course of the luminance changes of each monitor was measured with a photodiode. The p-VEPs elicited by these two screens were recorded from 15 eyes of 9 healthy volunteers (22.0 ± 0.8 years. Results. The OLED screen had a constant time delay from the onset of the trigger signal to the start of the luminescence change. The delay during the reversal phase from black to white for the pattern was 1.0 msec on the cathode-ray tube (CRT screen and 0.5 msec on the OLED screen. No significant differences in the amplitudes of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by the CRT and the OLED screens. Conclusion. The OLED screen can be used as a visual stimulator to elicit p-VEPs; however the time delay and the specific properties in the luminance change must be taken into account.

Investigating side chain mediated electroluminescence from carbazole-modified polyfluorene.

Science.gov (United States)

Liao, Jin-Long; Chen, Xiwen; Liu, Ching-Yang; Chen, Show-An; Su, Chiu-Huen; Su, An-Chung

2007-09-06

In molecular design of electroluminescent (EL) conjugated polymers, introducing a charge transport moiety on a side chain is found to be a promising method for balancing electron and hole fluxes in EL devices without changing the emitting color if there is no interaction between moiety and main chain. In the case of grafting a carbazole (Cz) moiety (hole transporting) on blue emitting polyfluorene, a green emission appears with intensity comparable to the blue emission, which was attributed to a possible interaction between main chain and Cz as previously reported by us. Here, a detailed study of its EL mechanism was carried out by means of time-resolved EL with the assistance of molecular simulation and thermally stimulated current measurements; exploration of how main chain segments interact with the transport moiety was performed. We found the Cz groups in Cz100PF play multiple roles: they act as (1) hole transporter to improve hole injection, (2) hole trapping site for efficient electron-hole recombination to yield blue-emitting excitons, and (3) source of green emission from electroplex formed via electric field-mediated interaction of the Cz/Cz radical cation with an electron in the nearby PF backbone. In combination, these observations suggest that integrated consideration for both intramolecular and intermolecular interactions provides a new route of molecular design of efficient EL polymers.

CCR5 delta32, matrix metalloproteinase-9 and disease activity in multiple sclerosis

DEFF Research Database (Denmark)

Sellebjerg, Finn; Madsen, Hans O; Jensen, Claus V

2000-01-01

Chemokines and matrix metalloproteinases (MMPs) appear to be crucial in leukocyte recruitment to the central nervous system in multiple sclerosis (MS). CCR5 delta32, a truncated allele of the CC chemokine receptor CCR5 gene encoding a non-functional receptor, did not confer protection from MS. CCR5...... delta32 was, however, associated with a lower risk of recurrent clinical disease activity. High CSF levels of MMP-9 activity were also associated with recurrent disease activity. These results directly link intrathecal inflammation to disease activity in patients with MS, suggesting that treatments...... targeting CCR5 or treatment with MMP inhibitors may attenuate disease activity in MS...

Stretchable Active Matrix Temperature Sensor Array of Polyaniline Nanofibers for Electronic Skin.

Science.gov (United States)

Hong, Soo Yeong; Lee, Yong Hui; Park, Heun; Jin, Sang Woo; Jeong, Yu Ra; Yun, Junyeong; You, Ilhwan; Zi, Goangseup; Ha, Jeong Sook

2016-02-03

A stretchable polyaniline nanofiber temperature sensor array with an active matrix consisting of single-walled carbon nanotube thin-film transistors is demonstrated. The integrated temperature sensor array gives mechanical stability under biaxial stretching of 30%, and the resultant spatial temperature mapping does not show any mechanical or electrical degradation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Near-infrared electroluminescence emission from an n-InN nanodots/p-Si heterojunction structure

International Nuclear Information System (INIS)

Wu Guoguang; Du Guotong; Gao Fubin; Shen Chunsheng; Li Wancheng; Wang Hui

2012-01-01

An n-InN nanodots/p-Si(1 1 1) heterojunction diode was fabricated by plasma-assisted molecular beam epitaxy. The device shows clear rectifying behaviour with a turn-on voltage of approximately 1.2 V at room temperature. The near-infrared electroluminescence (EL) can be observed under forward bias, which covers a wide wavelength range. In comparison with the photoluminescence spectra, the maximum of the EL spectra has a blueshift which is probably due to the size quantization effect of small-sized InN nanodots and their stronger contribution to the EL intensity. On the other hand, there is an obvious enhancement of the less dominant transitions on the short wavelength side of the EL spectra, which may arise from the recombination of the injected holes with the extremely high-density surface electrons of InN nanodots. (paper)

Room Temperature Electroluminescence from Tensile-Strained Si0.13Ge0.87/Ge Multiple Quantum Wells on a Ge Virtual Substrate

Directory of Open Access Journals (Sweden)

Guangyang Lin

2016-09-01

Full Text Available Direct band electroluminescence (EL from tensile-strained Si0.13Ge0.87/Ge multiple quantum wells (MQWs on a Ge virtual substrate (VS at room temperature is reported herein. Due to the competitive result of quantum confinement Stark effect and bandgap narrowing induced by tensile strain in Ge wells, electroluminescence from Γ1-HH1 transition in 12-nm Ge wells was observed at around 1550 nm. As injection current density increases, additional emission shoulders from Γ2-HH2 transition in Ge wells and Ge VS appeared at around 1300–1400 nm and 1600–1700 nm, respectively. The peak energy of EL shifted to the lower energy side superquadratically with an increase of injection current density as a result of the Joule heating effect. During the elevation of environmental temperature, EL intensity increased due to a reduction of energy between L and Γ valleys of Ge. Empirical fitting of the relationship between the integrated intensity of EL (L and injection current density (J with L~Jm shows that the m factor increased with injection current density, suggesting higher light emitting efficiency of the diode at larger injection current densities, which can be attributed to larger carrier occupations in the Γ valley and the heavy hole (HH valance band at higher temperatures.

Monolithic Active Pixel Matrix with Binary Counters ASIC with nested wells

International Nuclear Information System (INIS)

Fahim, F; Deptuch, G; Holm, S; Shenai, A; Lipton, R

2013-01-01

Monolithic Active Matrix with Binary Counters (MAMBO) V ASIC has been designed for detecting and measuring low energy X-rays. A nested well structure with a buried n-well (BNW) and a deeper buried p-well (BPW) is used to electrically isolate the detector from the electronics. BNW acts as an AC ground to electrical signals and behaves as a shield. BPW allows for a homogenous electric field in the entire detector volume. The ASIC consists of a matrix of 50 × 52 pixels, each of 105x105μm 2 . Each pixel contains analog functionality accomplished by a charge preamplifier, CR-RC 2 shaper and a baseline restorer. It also contains a window comparator with Upper and Lower thresholds which can be individually trimmed by 4 bit DACs to remove systematic offsets. The hits are registered by a 12 bit counter which is reconfigured as a shift register to serially output the data from the entire ASIC.

Fully Screen-Printed, Large-Area, and Flexible Active-Matrix Electrochromic Displays Using Carbon Nanotube Thin-Film Transistors.

Science.gov (United States)

Cao, Xuan; Lau, Christian; Liu, Yihang; Wu, Fanqi; Gui, Hui; Liu, Qingzhou; Ma, Yuqiang; Wan, Haochuan; Amer, Moh R; Zhou, Chongwu

2016-11-22

Semiconducting single-wall carbon nanotubes are ideal semiconductors for printed electronics due to their advantageous electrical and mechanical properties, intrinsic printability in solution, and desirable stability in air. However, fully printed, large-area, high-performance, and flexible carbon nanotube active-matrix backplanes are still difficult to realize for future displays and sensing applications. Here, we report fully screen-printed active-matrix electrochromic displays employing carbon nanotube thin-film transistors. Our fully printed backplane shows high electrical performance with mobility of 3.92 ± 1.08 cm 2 V -1 s -1 , on-off current ratio I on /I off ∼ 10 4 , and good uniformity. The printed backplane was then monolithically integrated with an array of printed electrochromic pixels, resulting in an entirely screen-printed active-matrix electrochromic display (AMECD) with good switching characteristics, facile manufacturing, and long-term stability. Overall, our fully screen-printed AMECD is promising for the mass production of large-area and low-cost flexible displays for applications such as disposable tags, medical electronics, and smart home appliances.

High resolution in situ zymography reveals matrix metalloproteinase activity at glutamatergic synapses.

Science.gov (United States)

Gawlak, M; Górkiewicz, T; Gorlewicz, A; Konopacki, F A; Kaczmarek, L; Wilczynski, G M

2009-01-12

Synaptic plasticity involves remodeling of extracellular matrix. This is mediated, in part, by enzymes of the matrix metalloproteinase (MMP) family, in particular by gelatinase MMP-9. Accordingly, there is a need of developing methods to visualize gelatinolytic activity at the level of individual synapses, especially in the context of neurotransmitters receptors. Here we present a high-resolution fluorescent in situ zymography (ISZ), performed in thin sections of the alcohol-fixed and polyester wax-embedded brain tissue of the rat (Rattus norvegicus), which is superior to the current ISZ protocols. The method allows visualization of structural details up to the resolution-limit of light microscopy, in conjunction with immunofluorescent labeling. We used this technique to visualize and quantify gelatinolytic activity at the synapses in control and seizure-affected rat brain. In particular, we demonstrated, for the first time, frequent colocalization of gelatinase(s) with synaptic N-methyl-D-aspartic acid (NMDA)- and AMPA-type glutamate receptors. We believe that our method represents a valuable tool to study extracellular proteolytic processes at the synapses, it could be used, as well, to investigate proteinase involvement in a range of physiological and pathological phenomena in the nervous system.

Ultraviolet-visible electroluminescence from metal-oxide-semiconductor devices with CeO2 films on silicon

International Nuclear Information System (INIS)

Lv, Chunyan; Zhu, Chen; Wang, Canxing; Li, Dongsheng; Ma, Xiangyang; Yang, Deren

2015-01-01

We report on ultraviolet-visible (UV-Vis) electroluminescence (EL) from metal-oxide-semiconductor (MOS) devices with the CeO 2 films annealed at low temperatures. At the same injection current, the UV-Vis EL from the MOS device with the 550 °C-annealed CeO 2 film is much stronger than that from the counterpart with the 450 °C-annealed CeO 2 film. This is due to that the 550 °C-annealed CeO 2 film contains more Ce 3+ ions and oxygen vacancies. It is tentatively proposed that the recombination of the electrons in multiple oxygen-vacancy–related energy levels with the holes in Ce 4f 1 energy band pertaining to Ce 3+ ions leads to the UV-Vis EL

Automatic Detection and Evaluation of Solar Cell Micro-Cracks in Electroluminescence Images Using Matched Filters

Energy Technology Data Exchange (ETDEWEB)

Spataru, Sergiu; Hacke, Peter; Sera, Dezso

2016-11-21

A method for detecting micro-cracks in solar cells using two dimensional matched filters was developed, derived from the electroluminescence intensity profile of typical micro-cracks. We describe the image processing steps to obtain a binary map with the location of the micro-cracks. Finally, we show how to automatically estimate the total length of each micro-crack from these maps, and propose a method to identify severe types of micro-cracks, such as parallel, dendritic, and cracks with multiple orientations. With an optimized threshold parameter, the technique detects over 90 % of cracks larger than 3 cm in length. The method shows great potential for quantifying micro-crack damage after manufacturing or module transportation for the determination of a module quality criterion for cell cracking in photovoltaic modules.

First proof of topological signature in high pressure xenon gas with electroluminescence amplification

CERN Document Server

Ferrario, P.; López-March, N.; Gómez-Cadenas, J.J.; Álvarez, V.; Azevedo, C.D.R.; Borges, F.I.G.; Cárcel, S.; Cebrián, S.; Cervera, A.; Conde, C.A.N.; Dafni, T.; Díaz, J.; Diesburg, M.; Esteve, R.; Fernandes, L.M.P.; Ferreira, A.L.; Freitas, E.D.C.; Gehman, V.M.; Goldschmidt, A.; González-Díaz, D.; Gutiérrez, R.M.; Hauptman, J.; Henriques, C.A.O.; Hernando Morata, J.A.; Irastorza, I.G.; Labarga, L.; Lebrun, P.; Liubarsky, I.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C.M.B.; Mora, F.J.; Moutinho, L.M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Novella, P.; Nygren, D.; Para, A.; Pérez, J.; Pérez Aparicio, J.L.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Santos, F.P.; dos Santos, J.M.F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J.F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J.F.C.A.; Villar, J.A.; Webb, R.; White, J.T.; Yahlali, N.; Yepes-Ramírez, H.

2016-01-01

The NEXT experiment aims to observe the neutrinoless double beta decay of xenon in a high-pressure Xe136 gas TPC using electroluminescence (EL) to amplify the signal from ionization. One of the main advantages of this technology is the possibility to reconstruct the topology of events with energies close to Qbb. This paper presents the first demonstration that the topology provides extra handles to reject background events using data obtained with the NEXT-DEMO prototype. Single electrons resulting from the interactions of Na22 1275 keV gammas and electron-positron pairs produced by conversions of gammas from the Th228 decay chain were used to represent the background and the signal in a double beta decay. These data were used to develop algorithms for the reconstruction of tracks and the identification of the energy deposited at the end-points, providing an extra background rejection factor of 24.3 +- 1.4 (stat.)%, while maintaining an efficiency of 66.7 +- 0.6 (stat.)% for signal events.

Contact light-emitting diodes based on vertical ZnO nanorods

Energy Technology Data Exchange (ETDEWEB)

Panin, G. N. [Dongguk University, Seoul (Korea, Republic of); Russian Academy of Sciences, Chernogolovka, Moscow district (Russian Federation); Cho, H. D.; Lee, S. W.; Kang, T. W. [Dongguk University, Seoul (Korea, Republic of)

2014-05-15

We report vertical contact light-emitting diodes (VCLEDs), that are based on heterojunctions formed by using the point contacts of n-ZnO nanorods (NRs) to the p-type semiconductor substrate and that are fabricated using a new approach to the formation of LEDs (Appl. Phys. Lett. 98, 093110 (2011)). A p-type GaN film grown on a sapphire substrate was used to form n-ZnO NRs/pGaN VCLEDs on a large area of about 4 cm{sup 2}. The VCLEDs emitted a pure blue electroluminescence with high efficiency. Electroluminescence at 470 nm, which is visible to the naked eye, started at small current of about 50 μA and is attributed to the good optical properties of the structurally perfect heterojunctions in the point contacts. The VCLED configuration allows the creation of ZnO/p-GaN nano-LEDs of high density and high-quality with a greatly reduced concentration of nonradiative defects in the active regions. The VCLEDs showed the high brightness of light required for active matrix displays and general solid-state lighting.

Development of immobilizing matrix for radioactive hearth ash of low activity level

International Nuclear Information System (INIS)

Greben'kov, A.J.; Kopets, Z.V.; Rytvinskaya, E.V.; Vecher, V.A.

2004-01-01

The incorporation of a certain quantity of the sorbing admixtures, i.e. the clay containing about 80 mas.% of montmorillonite, natural molding flask, into an ash-cement matrix allowed obtaining the hardened compounds with radioactive ash mass fraction of 40-60 mas.%, which physicochemical characteristics are significantly better that those required by regulations. This will facilitate the development of effective low active hearth ash utilization technologies. (authors)

Device Optimization and Transient Electroluminescence Studies of Organic light Emitting Devices

Energy Technology Data Exchange (ETDEWEB)

Lijuan Zou

2003-08-05

Organic light emitting devices (OLEDs) are among the most promising for flat panel display technologies. They are light, bright, flexible, and cost effective. And while they are emerging in commercial product, their low power efficiency and long-term degradation are still challenging. The aim of this work was to investigate their device physics and improve their performance. Violet and blue OLEDs were studied. The devices were prepared by thermal vapor deposition in high vacuum. The combinatorial method was employed in device preparation. Both continuous wave and transient electroluminescence (EL) were studied. A new efficient and intense UV-violet light emitting device was developed. At a current density of 10 mA/cm{sup 2}, the optimal radiance R could reach 0.38 mW/cm{sup 2}, and the quantum efficiency was 1.25%. using the delayed EL technique, electron mobilities in DPVBi and CBP were determined to be {approx} 10{sup -5} cm{sup 2}/Vs and {approx} 10{sup -4} cm{sup 2}/Vs, respectively. Overshoot effects in the transient El of blue light emitting devices were also observed and studied. This effect was attributed to the charge accumulation at the organic/organic and organic/cathode interfaces.

Device Optimization and Transient Electroluminescence Studies of Organic light Emitting Devices

International Nuclear Information System (INIS)

Lijuan Zou

2003-01-01

Organic light emitting devices (OLEDs) are among the most promising for flat panel display technologies. They are light, bright, flexible, and cost effective. And while they are emerging in commercial product, their low power efficiency and long-term degradation are still challenging. The aim of this work was to investigate their device physics and improve their performance. Violet and blue OLEDs were studied. The devices were prepared by thermal vapor deposition in high vacuum. The combinatorial method was employed in device preparation. Both continuous wave and transient electroluminescence (EL) were studied. A new efficient and intense UV-violet light emitting device was developed. At a current density of 10 mA/cm 2 , the optimal radiance R could reach 0.38 mW/cm 2 , and the quantum efficiency was 1.25%. using the delayed EL technique, electron mobilities in DPVBi and CBP were determined to be ∼ 10 -5 cm 2 /Vs and ∼ 10 -4 cm 2 /Vs, respectively. Overshoot effects in the transient El of blue light emitting devices were also observed and studied. This effect was attributed to the charge accumulation at the organic/organic and organic/cathode interfaces

Functionalized organic semiconductor molecules to enhance charge carrier injection in electroluminescent cell

Science.gov (United States)

Yalcin, Eyyup; Kara, Duygu Akin; Karakaya, Caner; Yigit, Mesude Zeliha; Havare, Ali Kemal; Can, Mustafa; Tozlu, Cem; Demic, Serafettin; Kus, Mahmut; Aboulouard, Abdelkhalk

2017-07-01

Organic semiconductor (OSC) materials as a charge carrier interface play an important role to improve the device performance of organic electroluminescent cells. In this study, 4,4″-bis(diphenyl amino)-1,1':3‧,1″-terphenyl-5'-carboxylic acid (TPA) and 4,4″-di-9H-carbazol-9-yl-1,1':3‧,1″-terphenyl-5'-carboxylic acid (CAR) has been designed and synthesized to modify indium tin oxide (ITO) layer as interface. Bare ITO and PEDOT:PSS coated on ITO was used as reference anode electrodes for comparison. Furthermore, PEDOT:PSS coated over CAR/ITO and TPA/ITO to observe stability of OSC molecules and to completely cover the ITO surface. Electrical, optical and surface characterizations were performed for each device. Almost all modified devices showed around 36% decrease at the turn on voltage with respect to bare ITO. The current density of bare ITO, ITO/CAR and ITO/TPA were measured as 288, 1525 and 1869 A/m2, respectively. By increasing current density, luminance of modified devices showed much better performance with respect to unmodified devices.

Room-temperature near-infrared electroluminescence from boron-diffused silicon pn junction diodes

Directory of Open Access Journals (Sweden)

Si eLi

2015-02-01

Full Text Available Silicon pn junction diodes with different doping concentrations were prepared by boron diffusion into Czochralski (CZ n-type silicon substrate. Their room-temperature near-infrared electroluminescence (EL was measured. In the EL spectra of the heavily boron doped diode, a luminescence peak at ~1.6 m (0.78 eV was observed besides the band-to-band line (~1.1eV under the condition of high current injection, while in that of the lightly boron doped diode only the band-to-band line was observed. The intensity of peak at 0.78 eV increases exponentially with current injection with no observable saturation at room temperature. Furthermore, no dislocations were found in the cross-sectional transmission electron microscopy image, and no dislocation-related luminescence was observed in the low-temperature photoluminescence spectra. We deduce the 0.78 eV emission originates from the irradiative recombination in the strain region of diodes caused by the diffusion of large number of boron atoms into silicon crystal lattice.

Correcting the effects of the matrix using capture gamma-ray spectrometry: Application to measurement by Active Neutron Interrogation

International Nuclear Information System (INIS)

Baudry, G.

2003-11-01

In the field of the measurement of low masses of fissile material ( 235 U, 239 Pu, 241 Pu) in radioactive waste drums, the Active Neutron Interrogation is a non-destructive method achieving good results. It does however remain reliant upon uncertainties related to the matrix effects on interrogation and fission neutrons. The aim of this thesis is to develop a correction method able to take into account these matrix effects by quantifying the amount of absorbent materials (chlorine and hydrogen) in a 118- liter homogeneous matrix. The main idea is to use the gamma-ray spectrometry of gamma emitted by neutron captures to identify and quantify the composition of the matrix. An indicator from its chlorine content is then deduced in order to choose the calibration coefficient which best represents the real composition of the matrix. This document firstly presents the needs of control and characterization of radioactive objects, and the means used in the field of nuclear measurement. Emphases is put in particular on the Active Neutron Interrogation method. The matrices of interest are those made of light technological waste (density ≤ 0,4 g/cm 3 ) containing hydrogenated and chlorinated materials. The advantages of gamma-rays emitted by neutron captures for the determination of a chlorine content indicator of the matrices and the principles of the correction method are then explained. Measurements have been firstly realized with an existing Neutron Interrogation device (PROMETHEE 6). Such measurements have proven its inadequacy: no signal from the matrix hydrogen was detected, due to an intense signal from the polyethylene contained in some cell elements. Moreover, the matrix chlorine content appeared difficult to be measured. A new and specific device, named REGAIN and dedicated to active gamma-rays spectrometry, was defined with the Monte-Carlo N-Particle (MCNP) code. The experiments conducted with this new device made it possible to detect the hydrogen from the

Resveratrol increases nucleus pulposus matrix synthesis through activating the PI3K/Akt signaling pathway under mechanical compression in a disc organ culture.

Science.gov (United States)

Han, Xiaorui; Leng, Xiaoming; Zhao, Man; Wu, Mei; Chen, Amei; Hong, Guoju; Sun, Ping

2017-12-22

Disc nucleus pulposus (NP) matrix homeostasis is important for normal disc function. Mechanical overloading seriously decreases matrix synthesis and increases matrix degradation. The present study aims to investigate the effects of resveratrol on disc NP matrix homeostasis under a relatively high-magnitude mechanical compression and the potential mechanism underlying this process. Porcine discs were perfusion-cultured and subjected to a relatively high-magnitude mechanical compression (1.3 MPa at a frequency of 1.0 Hz for 2 h once per day) for 7 days in a mechanically active bioreactor. The non-compressed discs were used as controls. Resveratrol was added along with culture medium to observe the effects of resveratrol on NP matrix synthesis under mechanical load respectively. NP matrix synthesis was evaluated by histology, biochemical content (glycosaminoglycan (GAG) and hydroxyproline (HYP)), and expression of matrix macromolecules (aggrecan and collagen II). Results showed that this high-magnitude mechanical compression significantly decreased NP matrix content, indicated by the decreased staining intensity of Alcian Blue and biochemical content (GAG and HYP), and the down-regulated expression of NP matrix macromolecules (aggrecan and collagen II). Further analysis indicated that resveratrol partly stimulated NP matrix synthesis and increased activity of the PI3K/Akt pathway in a dose-dependent manner under mechanical compression. Together, resveratrol is beneficial for disc NP matrix synthesis under mechanical overloading, and the activation of the PI3K/Akt pathway may participate in this regulatory process. Resveratrol may be promising to regenerate mechanical overloading-induced disc degeneration. © 2017 The Author(s).

Reactive Chemical Vapor Deposition Method as New Approach for Obtaining Electroluminescent Thin Film Materials

Directory of Open Access Journals (Sweden)

Valentina V. Utochnikova

2012-01-01

Full Text Available The new reactive chemical vapor deposition (RCVD method has been proposed for thin film deposition of luminescent nonvolatile lanthanide aromatic carboxylates. This method is based on metathesis reaction between the vapors of volatile lanthanide dipivaloylmethanate (Ln(dpm3 and carboxylic acid (HCarb orH2Carb′ and was successfully used in case of HCarb. Advantages of the method were demonstrated on example of terbium benzoate (Tb(bz3 and o-phenoxybenzoate thin films, and Tb(bz3 thin films were successfully examined in the OLED with the following structure glass/ITO/PEDOT:PSS/TPD/Tb(bz3/Ca/Al. Electroluminescence spectra of Tb(bz3 showed only typical luminescent bands, originated from transitions of the terbium ion. Method peculiarities for deposition of compounds of dibasic acids H2Carb′ are established on example of terbium and europium terephtalates and europium 2,6-naphtalenedicarboxylate.

Two-phase Cryogenic Avalanche Detector with electroluminescence gap operated in argon doped with nitrogen

Energy Technology Data Exchange (ETDEWEB)

Bondar, A.; Buzulutskov, A. [Budker Institute of Nuclear Physics SB RAS, Lavrentiev avenue 11, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogov street 2, 630090 Novosibirsk (Russian Federation); Dolgov, A. [Novosibirsk State University, Pirogov street 2, 630090 Novosibirsk (Russian Federation); Nosov, V.; Shekhtman, L.; Shemyakina, E.; Sokolov, A. [Budker Institute of Nuclear Physics SB RAS, Lavrentiev avenue 11, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogov street 2, 630090 Novosibirsk (Russian Federation)

2017-02-11

A two-phase Cryogenic Avalanche Detector (CRAD) with electroluminescence (EL) gap, operated in argon doped with a minor (49±7 ppm) admixture of nitrogen, has been studied. The EL gap was optically read out using cryogenic PMTs located on the perimeter of the gap. We present the results of the measurements of the N{sub 2} content, detector sensitivity to X-ray-induced signals, EL gap yield and electron lifetime in the liquid. The detector sensitivity, at a drift field in liquid Ar of 0.6 kV/cm, was measured to be 9 and 16 photoelectrons recorded at the PMTs per keV of deposited energy at 23 and 88 keV respectively. Such two-phase detectors, with enhanced sensitivity to the S2 (ionization-induced) signal, are relevant in the field of argon detectors for dark matter search and low energy neutrino detection.

Emission characteristics in solution-processed asymmetric white alternating current field-induced polymer electroluminescent devices

Science.gov (United States)

Chen, Yonghua; Xia, Yingdong; Smith, Gregory M.; Gu, Yu; Yang, Chuluo; Carroll, David L.

2013-01-01

In this work, the emission characteristics of a blue fluorophor poly(9, 9-dioctylfluorene) (PFO) combined with a red emitting dye: Bis(2-methyl-dibenzo[f,h]quinoxaline)(acetylacetonate)iridium (III) [Ir(MDQ)2(acac)], are examined in two different asymmetric white alternating current field-induced polymer electroluminescent (FIPEL) device structures. The first is a top-contact device in which the triplet transfer is observed resulting in the concentration-dependence of the emission similar to the standard organic light-emitting diode (OLED) structure. The second is a bottom-contact device which, however, exhibits concentration-independence of emission. Specifically, both dye emission and polymer emission are found for the concentrations as high as 10% by weight of the dye in the emitter. We attribute this to the significant different carrier injection characteristics of the two FIPEL devices. Our results suggest a simple and easy way to realize high-quality white emission.

Temperature dependence of electron mobility, electroluminescence and photoluminescence of Alq{sub 3} in OLED

Energy Technology Data Exchange (ETDEWEB)

Mu Haichuan; White, Dan; Sharpton, Buck [Office of Electronic Miniaturization, University of Alaska at Fairbanks, AK 99701 (United States); Klotzkin, David [Department of Electrical and Computer Engineering and Computer Sciences, University of Cincinnati, Cincinnati, OH 45221 (United States); De Silva, Ajith; Wagner, Hans Peter [Department of Physics, University of Cincinnati, Cincinnati, OH 45221 (United States)], E-mail: fnhm@uaf.edu

2008-12-07

The correlation of electroluminescence (EL), photoluminescence (PL) and electron mobility were investigated over temperature from 60 to 300 K in small-molecule organic light emitting diode (OLED) structures. The devices consisted of ITO/PEDOT(50 nm)/TPD(50 nm)/Alq{sub 3}(60 nm)/LiF(1 nm)/Al(90 nm), and were fabricated with high-vacuum sublimation/evaporation in a cross-linked configuration. Electron mobility was measured using an ac analysis of the device optical modulation characteristics, while PL and EL were measured by measuring optical power out at fixed pump power of 1 mW, and analysis of dc brightness-voltage (L-V) characteristics, respectively. PL intensity and mobility had a clear maximum at around 220 K, while EL efficiency was constant below 220 K and decrease monotonically above. The reason for the temperature dependent EL, PL and electron mobility behaviour will be discussed.

Electroluminescence analysis for spatial characterization of parasitic optical losses in silicon heterojunction solar cells

Science.gov (United States)

Ahmed, Nuha; Zhang, Lei; Sriramagiri, Gowri; Das, Ujjwal; Hegedus, Steven

2018-04-01

Electroluminescence (EL) coupled with reflection measurements are used to spatially quantify optical losses in silicon heterojunction solar cells due to plasmonic absorption in the metal back contacts. The effect of indium tin oxide back reflector in decreasing this plasmonic absorption is found to increase the reflection from the back nickel (Ni)-aluminum (Al) and Al metals by ˜12% and ˜41%, respectively, in both bifacial and front junction silicon solar cells. Losses due to back reflection are calculated by comparison between the EL emission signals in high and low back reflection samples and are shown to be in agreement with standard reflection measurements. We conclude that the optical properties of the back contact can significantly influence the EL intensity which complicates the interpretation of EL as being primarily due to recombination especially when comparing two different devices with spatially varying back surface structures.

Thermally Activated Delayed Fluorescence Emitters for Deep Blue Organic Light Emitting Diodes: A Review of Recent Advances

Directory of Open Access Journals (Sweden)

Thanh-Tuân Bui

2018-03-01

Full Text Available Organic light-emitting diodes offer attractive perspectives for the next generation display and lighting technologies. The potential is huge and the list of potential applications is almost endless. So far, blue emitters still suffer from noticeably inferior electroluminescence performances in terms of efficiency, lifespan, color quality, and charge injection/transport when compared to that of the other colors. Emitting materials matching the NTSC standard blue of coordinates (0.14, 0.08 are extremely rare and still constitutes the focus of numerous academic and industrial researches. In this context, we review herein the recent developments on highly emissive deep-blue thermally activated delayed fluorescence emitters that constitute the third-generation electroluminescent materials.

The effect of tomatine on metastasis related matrix metalloproteinase (MMP) activities in breast cancer cell model.

Science.gov (United States)

Yelken, Besra Özmen; Balcı, Tuğçe; Süslüer, Sunde Yılmaz; Kayabaşı, Çağla; Avcı, Çığır Biray; Kırmızıbayrak, Petek Ballar; Gündüz, Cumhur

2017-09-05

Breast cancer is one of the most common malignancies in women and metastasis is the cause of morbidity and mortality in patients. In the development of metastasis, the matrix metalloproteinase (MMP) family has a very important role in tumor development. MMP-2 and MMP-9 work together for extracellular matrix (ECM) cleavage to increase migration. Tomatine is a secondary metabolite that has a natural defense role against plants, fungi, viruses and bacteria that are synthesized from tomato. In additıon, tomatine is also known that it breaks down the cell membrane and is a strong inhibitor in human cancer cells. In this study, it was aimed to evaluate the effect of tomatine on cytotoxicity, apoptosis and matrix metalloproteinase inhibition in MCF-7 cell lines. Human breast cancer cell line (MCF-7) was used as a cell line. In MCF-7 cells, the IC 50 dose of tomatine was determined to be 7.07μM. According to the control cells, apoptosis increased 3.4 fold in 48thh. Activation of MMP-2, MMP-9 and MMP-9\\NGAL has been shown to decrease significantly in cells treated with tomatine by gelatin zymography compared to the control. As a result, matrix metalloproteinase activity and cell proliferation were suppressed by tomatine and this may provide support in treatment methods. Copyright © 2017 Elsevier B.V. All rights reserved.

Preferential binding of DNA primase to the nuclear matrix

International Nuclear Information System (INIS)

Wood, S.H.; Collins, J.M.

1986-01-01

Several lines of research have stimulated interest in the nuclear matrix as the subcellular site of DNA replication. The authors have recently reported a relationship between rates of DNA synthesis and the differential binding of polymerase α to the nuclear matrix. They now report the detection of DNA primase bound to the HeLa nuclear matrix. Matrix-bound primase can be measured either indirectly, by the incorporation of [ 32 P] dAMP into an unprimed single-stranded template, or directly, by the incorporation of [ 3 H] AMP into matrix DNA. Characteristics of this system include a requirement for ATP, inhibition by adenosine-5'-0-(3'-thiotriphosphate), a primase inhibitor, and insensitivity to aphidicolin and α-amanitine, inhibitors of polymerase α and RNA polymerase, respectively. Subcellular quantification of primase and polymerase α activity revealed that while a majority of primase activity is bound to the matrix (72%), only 32% of polymerase α activity is matrix-bound. Treatment of the nuclear matrix with β-D-Octylglucoside allowed the solubilization of 54% of primase activity and 39% of polymerase α activity. This data provides further evidence of a structural and functional role for the nuclear matrix in DNA replication. The ability to solubilize matrix-bound replicative enzymes may prove to be an important tool in the elucidation of the spatial organization of DNA replication

Efficient blue-green and green electroluminescent devices obtained by doping iridium complexes into hole-block material as supplementary light-emitting layer

Energy Technology Data Exchange (ETDEWEB)

Zhou, Liang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zheng, Youxuan, E-mail: yxzheng@mail.nju.edu.cn [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Deng, Ruiping; Feng, Jing; Song, Mingxing; Hao, Zhaomin [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zhang, Hongjie, E-mail: hongjie@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zuo, Jinglin; You, Xiaozeng [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

2014-04-15

In this work, organic electroluminescent (EL) devices with dominant and supplementary light-emitting layers (EMLs) were designed to further improve the EL performances of two iridium{sup III}-based phosphorescent complexes, which have been reported to provide EL devices with slow EL efficiency roll-off. The widely used hole-block material 2,2′,2''-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) was selected as host material to construct the supplementary EML. Compared with single-EML devices, double-EMLs devices showed higher EL efficiencies, higher brightness, and lower operation voltage attributed to wider recombination zone and better balance of carriers. In addition, the insertion of supplementary EML is instrumental in facilitating carriers trapping, thus improving the color purity. Finally, high performance blue-green and green EL devices with maximum current efficiencies of 35.22 and 90.68 cd/A, maximum power efficiencies of 26.36 and 98.18 lm/W, and maximum brightness of 56,678 and 112,352 cd/m{sup 2}, respectively, were obtained by optimizing the doping concentrations. Such a device design strategy extends the application of a double EML device structure and provides a chance to simplify device fabrication processes. -- Highlights: • Electroluminescent devices with supplementary light-emitting layer were fabricated. • Doping concentrations and thicknesses were optimized. • Better balance of holes and electrons causes the enhanced efficiency. • Improved carrier trapping suppresses the emission of host material.

Electroluminescence dependence of the simplified green light organic light emitting diodes on in situ thermal treatment

Energy Technology Data Exchange (ETDEWEB)

Mu, Haichuan, E-mail: hcmu@ecust.edu.cn [Department of Physics, School of Science, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Rao, Lu [Department of Physics, School of Science, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Li, Weiling; Wei, Bin [Key Laboratory of Advanced Display and System Applications, Ministry of Education, School of Mechanics Engineering and Automation, Shanghai University, 149 Yanchang Road, Shanghai 200072 (China); Wang, Keke; Xie, Haifen [Department of Physics, School of Science, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)

2015-12-01

Highlights: • In-situ thermal treating the organic tri-layer (CBP/CBP:Ir(ppy){sub 3}/TPBi) of the green light PHOLED under various temperatures during the organic materials evaporation. • Investigating the effect of in situ thermal treatment on the electroluminescence (EL) performance of the green light PHOLED with tri-layer structures. • Provide an easy and practical way to improve the EL performance of the OLEDs without major modification of the organic materials and OLEDs structures required. - Abstract: Simplified multilayer green light phosphorescent organic light emitting diodes (PHOLED) with the structure of ITO/MoO{sub 3}(1 nm)/CBP(20 nm)/CBP:Ir(ppy){sub 3} (1 wt%) (15 nm)/TPBi(60 nm)/LiF(0.5 nm)/Al were fabricated via thermal evaporation and in situ thermal treatment (heating the OLED substrates to certain temperatures during the thermal evaporation of the organic materials) was performed. The effect of the in situ thermal treatment on the electroluminescence (EL) performance of the PHOLED was investigated. It was found that the OLED exhibited strong EL dependence on the thermal treatment temperatures, and their current efficiency was improved with the increasing temperature from room temperature (RT) to 69 °C and deteriorated with the further increasing temperature to 105 °C. At the brightness of 1000 cd/m{sup 2}, over 80% improvement of the current efficiency at the optimal thermal treatment temperature of 69 °C (64 cd/A) was demonstrated compared to that at RT (35 cd/A). Meanwhile, the tremendous influences of the in situ thermal treatment on the morphology of the multilayer CBP/CBP:Ir(ppy){sub 3}/TPBi were also observed. At the optimal thermal treatment temperature of 69 °C, the improvement of the EL performance could be ascribed to the enhancement of the electron and hole transporting in the CBP:Ir(ppy){sub 3} emitting layer, which suppressed the triplets self-quenching interactions and promoted the charge balance and excitons formation. The

Single step deposition of an interacting layer of a perovskite matrix with embedded quantum dots

Science.gov (United States)

Ngo, Thi Tuyen; Suarez, Isaac; Sanchez, Rafael S.; Martinez-Pastor, Juan P.; Mora-Sero, Ivan

2016-07-01

Hybrid lead halide perovskite (PS) derivatives have emerged as very promising materials for the development of optoelectronic devices in the last few years. At the same time, inorganic nanocrystals with quantum confinement (QDs) possess unique properties that make them suitable materials for the development of photovoltaics, imaging and lighting applications, among others. In this work, we report on a new methodology for the deposition of high quality, large grain size and pinhole free PS films (CH3NH3PbI3) with embedded PbS and PbS/CdS core/shell Quantum Dots (QDs). The strong interaction between both semiconductors is revealed by the formation of an exciplex state, which is monitored by photoluminescence and electroluminescence experiments. The radiative exciplex relaxation is centered in the near infrared region (NIR), ~1200 nm, which corresponds to lower energies than the corresponding band gap of both perovskite (PS) and QDs. Our approach allows the fabrication of multi-wavelength light emitting diodes (LEDs) based on a PS matrix with embedded QDs, which show considerably low turn-on potentials. The presence of the exciplex state of PS and QDs opens up a broad range of possibilities with important implications in both LEDs and solar cells.Hybrid lead halide perovskite (PS) derivatives have emerged as very promising materials for the development of optoelectronic devices in the last few years. At the same time, inorganic nanocrystals with quantum confinement (QDs) possess unique properties that make them suitable materials for the development of photovoltaics, imaging and lighting applications, among others. In this work, we report on a new methodology for the deposition of high quality, large grain size and pinhole free PS films (CH3NH3PbI3) with embedded PbS and PbS/CdS core/shell Quantum Dots (QDs). The strong interaction between both semiconductors is revealed by the formation of an exciplex state, which is monitored by photoluminescence and

Integrins and extracellular matrix in mechanotransduction

Directory of Open Access Journals (Sweden)

Ramage L

2011-12-01

Full Text Available Lindsay RamageQueen’s Medical Research Institute, University of Edinburgh, Edinburgh, UKAbstract: Integrins are a family of cell surface receptors which mediate cell–matrix and cell–cell adhesions. Among other functions they provide an important mechanical link between the cells external and intracellular environments while the adhesions that they form also have critical roles in cellular signal-transduction. Cell–matrix contacts occur at zones in the cell surface where adhesion receptors cluster and when activated the receptors bind to ligands in the extracellular matrix. The extracellular matrix surrounds the cells of tissues and forms the structural support of tissue which is particularly important in connective tissues. Cells attach to the extracellular matrix through specific cell-surface receptors and molecules including integrins and transmembrane proteoglycans. Integrins work alongside other proteins such as cadherins, immunoglobulin superfamily cell adhesion molecules, selectins, and syndecans to mediate cell–cell and cell–matrix interactions and communication. Activation of adhesion receptors triggers the formation of matrix contacts in which bound matrix components, adhesion receptors, and associated intracellular cytoskeletal and signaling molecules form large functional, localized multiprotein complexes. Cell–matrix contacts are important in a variety of different cell and tissue properties including embryonic development, inflammatory responses, wound healing, and adult tissue homeostasis. This review summarizes the roles and functions of integrins and extracellular matrix proteins in mechanotransduction.Keywords: ligand binding, α subunit, ß subunit, focal adhesion, cell differentiation, mechanical loading, cell–matrix interaction

Matrix Metalloproteinase Enzyme Family

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Ozlem Goruroglu Ozturk

2013-04-01

Full Text Available Matrix metalloproteinases play an important role in many biological processes such as embriogenesis, tissue remodeling, wound healing, and angiogenesis, and in some pathological conditions such as atherosclerosis, arthritis and cancer. Currently, 24 genes have been identified in humans that encode different groups of matrix metalloproteinase enzymes. This review discuss the members of the matrix metalloproteinase family and their substrate specificity, structure, function and the regulation of their enzyme activity by tissue inhibitors. [Archives Medical Review Journal 2013; 22(2.000: 209-220

An Active Plasmonic to Explore on-Chip Sensing Applications

Directory of Open Access Journals (Sweden)

Nan-Fu Chiu

2016-06-01

Full Text Available We report the influence of top emission and transparent organic electroluminescence (OEL devices on the color tunability, viewing angle and enhancement light efficiency by surface plasmon grating coupled emission (SPGCE, the effects of coupled active SPPs on the metal nano-grating with organic material interface by cross-coupled into far-field space. Owing to the narrow band emission from the SPGCE, one can observe clear color changes at a certain viewing angle with different permittivities. The experimental and theoretical results showed that OEL-SPGCE at different pitch can match a linear shifting of momentum (DK of about 4.8 mm-1 per 100 nm pitch size. The color changes from -1.1 degree (water, -.07 degree (glucose 10 %, -2.5 degree (glucose 20 %, to 6 degree (glucose 40 % with the increasing permittivities. The OEL-SPGCE biosensor is proposed for the development of novel devices, which is expected to improve the capability of electroluminescent bio-plasmonic resonance measurement devices in the future.

STM-electroluminescence from clustered C3N4 nanodomains synthesized via green chemistry process.

Science.gov (United States)

Andrade, E P; Costa, B B A; Chaves, C R; de Paula, A M; Cury, L A; Malachias, A; Safar, G A M

2018-01-01

A Scanning Tunneling Microscopy/Spectroscopy (STM/STS) and synchrotron X-ray diffraction study on clustered C 3 N 4 nanoparticles (nanoflakes) is conducted on green-chemistry synthesized samples obtained from chitosan through high power sonication. Morphological aspects and the electronic characteristics are investigated. The observed bandgap of the nanoflakes reveals the presence of different phases in the material. Combining STM morphology, STS spectra and X-ray diffraction (XRD) results one finds that the most abundant phase is graphitic C 3 N 4 . A high density of defects is inferred from the XRD measurements. Additionally, STM-electroluminescence (STMEL) is detected in C 3 N 4 nanoflakes deposited on a gold substrate. The tunneling current creates photons that are three times more energetic than the tunneling electrons of the STM sample. We ponder about the two most probable models to explain the observed photon emission energy: either a nonlinear optical phenomenon or a localized state emission. Copyright © 2017 Elsevier B.V. All rights reserved.

Omega-3 and Omega-6 Fatty Acids Act as Inhibitors of the Matrix Metalloproteinase-2 and Matrix Metalloproteinase-9 Activity.

Science.gov (United States)

Nicolai, Eleonora; Sinibaldi, Federica; Sannino, Gianpaolo; Laganà, Giuseppina; Basoli, Francesco; Licoccia, Silvia; Cozza, Paola; Santucci, Roberto; Piro, Maria Cristina

2017-08-01

Polyunsaturated fatty acids have been reported to play a protective role in a wide range of diseases characterized by an increased metalloproteinases (MMPs) activity. The recent finding that omega-3 and omega-6 fatty acids exert an anti-inflammatory effect in periodontal diseases has stimulated the present study, designed to determine whether such properties derive from a direct inhibitory action of these compounds on the activity of MMPs. To this issue, we investigated the effect exerted by omega-3 and omega-6 fatty acids on the activity of MMP-2 and MMP-9, two enzymes that actively participate to the destruction of the organic matrix of dentin following demineralization operated by bacteria acids. Data obtained (both in vitro and on ex-vivo teeth) reveal that omega-3 and omega-6 fatty acids inhibit the proteolytic activity of MMP-2 and MMP-9, two enzymes present in dentin. This observation is of interest since it assigns to these compounds a key role as MMPs inhibitors, and stimulates further study to better define their therapeutic potentialities in carious decay.

Far-field self-focusing and -defocusing radiation behaviors of the electroluminescent light sources due to negative refraction.

Science.gov (United States)

Yin, Yu-Feng; Lin, Yen-Chen; Tsai, Tsung-Han; Shen, Yi-Chun; Huang, Jianjang

2013-01-15

In recent years, researchers have demonstrated negative refraction theoretically and experimentally by pumping optical power into photonic crystal (PhC) or waveguide structures. The concept of negative refraction can be used to create a perfect lens that focuses an object smaller than the wavelength. By inserting two-dimensional PhCs into the peripheral of a semiconductor light emitting structure, this study presents an electroluminescent device with negative refraction in the visible wavelength range. This approach produces polarization dependent collimation behavior in far-field radiation patterns. The modal dispersion of negative refraction results in strong group velocity modulation, and self-focusing and -defocusing behaviors are apparent from light extraction. This study further verifies experimental results by using theoretic calculations based on equifrequency contours.

Spectrally resolved hyperfine interactions between polaron and nuclear spins in organic light emitting diodes: Magneto-electroluminescence studies

Energy Technology Data Exchange (ETDEWEB)

Crooker, S. A.; Kelley, M. R.; Martinez, N. J. D.; Nie, W.; Mohite, A.; Nayyar, I. H.; Tretiak, S.; Smith, D. L. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Liu, F.; Ruden, P. P. [University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2014-10-13

We use spectrally resolved magneto-electroluminescence (EL) measurements to study the energy dependence of hyperfine interactions between polaron and nuclear spins in organic light-emitting diodes. Using layered devices that generate bright exciplex emission, we show that the increase in EL emission intensity I due to small applied magnetic fields of order 100 mT is markedly larger at the high-energy blue end of the EL spectrum (ΔI/I ∼ 11%) than at the low-energy red end (∼4%). Concurrently, the widths of the magneto-EL curves increase monotonically from blue to red, revealing an increasing hyperfine coupling between polarons and nuclei and directly providing insight into the energy-dependent spatial extent and localization of polarons.

Electroluminescence from ZnO/Si heterojunctions fabricated by PLD with bias voltage application

Science.gov (United States)

Seno, Yuuki; Konno, Daisuke; Komiyama, Takao; Chonan, Yasunori; Yamaguchi, Hiroyuki; Aoyama, Takashi

2014-02-01

Electroluminescence (EL) for ZnO films has been investigated by fabricating n-ZnO/p-Si heterojunctions and changing the VI/II (O/Zn) ratio of the films. In the photoluminescence (PL) spectra, both the near band edge (NBE) emission and the defect-related emission were observed, while in the EL spectra only defect-related emission was observed. The EL spectra were divided into three components: green (550 nm), yellow (618 nm) and red (700 nm) bands; and their intensities were compared. As the VI/II (O/Zn) ratio was increased, the red band emission intensity decreased and the green band emission intensity increased. This implies that the oxygen and the zinc vacancies are related to the red and the green band emissions, respectively. Electron transitions from the conduction band minimum (Ec) to the deep energy levels of these vacancies are suggested to cause the red and the green luminescences while the energy levels of the Zn interstitials are close to the Ec in the band gap and no NBE emission is observed.

Electroluminescence from ZnO/Si heterojunctions fabricated by PLD with bias voltage application

International Nuclear Information System (INIS)

Seno, Yuuki; Konno, Daisuke; Komiyama, Takao; Chonan, Yasunori; Yamaguchi, Hiroyuki; Aoyama, Takashi

2014-01-01

Electroluminescence (EL) for ZnO films has been investigated by fabricating n-ZnO/p-Si heterojunctions and changing the VI/II (O/Zn) ratio of the films. In the photoluminescence (PL) spectra, both the near band edge (NBE) emission and the defect-related emission were observed, while in the EL spectra only defect-related emission was observed. The EL spectra were divided into three components: green (550 nm), yellow (618 nm) and red (700 nm) bands; and their intensities were compared. As the VI/II (O/Zn) ratio was increased, the red band emission intensity decreased and the green band emission intensity increased. This implies that the oxygen and the zinc vacancies are related to the red and the green band emissions, respectively. Electron transitions from the conduction band minimum (Ec) to the deep energy levels of these vacancies are suggested to cause the red and the green luminescences while the energy levels of the Zn interstitials are close to the Ec in the band gap and no NBE emission is observed

Investigations on electroluminescent tapes and foils in relation to their applications in automotive

Science.gov (United States)

Plotog, Ioan

2015-02-01

The electroluminescent (EL) tapes or foils having barrier films for an additional level of protection against the toughest environments conditions, offer a large area of applications. The EL lights, due to their characteristics, began to be used not only in the entertainment industry, but also for automotive and aerospace applications. In the paper, the investigations regarding EL foils technical performances in relation to their applications as light sources in automotive ambient light were presented. The experiments were designed based on the results of EL foils electrical properties previous investigations done in laboratory conditions, taking into account the range of automotive ambient temperatures for sinusoidal alternative supply voltage. The measurements for different temperatures were done by keeping the EL foils into electronic controlled oven that ensures the dark enclosure offering conditions to use a lux-meter in order to measure and maintain under control light emission intensity. The experiments results define the EL foils characteristics as load in automotive ambient temperatures condition, assuring so the data for optimal design of a dedicated inverter.

Synthesis and electroluminescence properties of europium (III) complexes with new second ligands

International Nuclear Information System (INIS)

Liu Ze; Wen Fushan; Li Wenlian

2005-01-01

Two novel second ligands, 9,9-Di-(4-methoxyphenyl)-9-H-4,5-' (OMe-Spiro-DF) and 9,9-Di-(2-(4-(4-butyloxy)phenyl)-5-phenyl-1,3,4-oxadiazolyl)-phenyl-9-H-4, 5-Diazafluorene (OXD-Spiro-DF), were successfully prepared. Europium complexes, Eu(DBM) 3 (OMe-Spiro-DF) and Eu(DBM) 3 (OXD-Spiro-DF) (DBM=dibenzolylmethane) based on the two ligands were designed and synthesized. For a double-layer device with configuration of indium tin oxide (ITO)/N, N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD)/Eu(DBM) 3 (OXD-Spiro-DF) or Eu(DBM) 3 (OMe-Spiro-DF)/Mg/Ag, compared with the device based on complex Eu(DBM) 3 (OMe-Spiro-DF), the brightness and electroluminescent (EL) efficiency of device based on complex Eu(DBM) 3 (OXD-Spiro-DF) with oxadiazole-functionalized ligand OXD-Spiro-DF are significantly improved due to the improvement of electron-transporting ability. A maximum brightness of 154 cd/m 2 was obtained at 17 V in the complex Eu(DBM) 3 (OXD-Spiro-DF), about four times brighter than the corresponding complex Eu(DBM) 3 (OMe-Spiro-DF)

Study of electron mobility in small molecular SAlq by transient electroluminescence method

Science.gov (United States)

Kumar, Pankaj; Jain, S. C.; Kumar, Vikram; Chand, Suresh; Kamalasanan, M. N.; Tandon, R. P.

2007-12-01

The study of electron mobility of bis(2-methyl 8-hydroxyquinoline) (triphenyl siloxy) aluminium (SAlq) by transient electroluminescence (EL) is presented. An EL device is fabricated in bilayer, ITO/N,N'-diphenyl-N, N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD)/SAlq/LiF/Al configuration. The temporal evaluation of the EL with respect to the step voltage pulse is characterized by a delay time followed by a fast initial rise, which is followed by a slower rise. The delay time between the applied electrical pulse and the onset of EL is correlated with the carrier mobility (electron in our case). Transient EL studies for SAlq have been carried out at different temperatures and different applied electric fields. The electron mobility in SAlq is found to be field and temperature dependent and calculated to be 6.9 × 10-7 cm2 V-1 s-1 at 2.5 × 106 V cm-1 and 308 K. The EL decays immediately as the voltage is turned off and does not depend on the amplitude of the applied voltage pulse or dc offset.

Electroluminescence and Photoluminescence from a Fluorescent Cobalt Porphyrin Grafted on Graphene Oxide

Science.gov (United States)

Janghouri, Mohammad

2017-10-01

A new graphene oxide-cobalt porphyrin (GO-CoTPP) hybrid material has been used as an emissive layer in organic light-emitting diodes (OLEDs). Devices with fundamental structure of indium-doped tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS, 45 nm)/polyvinylcarbazole (PVK):2-(4-biphenyl)-5-(4- t-butylphenyl)-1,3,4-oxadiazole (PBD):GO-CoTPP (70 nm)/1,3,5-tris( N-phenylbenzimidazol-2-yl)-benzene (TPBI, 20 nm)/Al (150 nm) were fabricated. A red electroluminescence (EL) was obtained from thin-film PVK:PBD:CoTPP at 70 nm thickness. When CoTPP was covalently grafted on graphene oxide (GO) sheets, near-white EL was obtained. The white emission, which was composed of bluish green and red, is attributed to electroplex formation at the GO-CoTPP/PBD interface. Such electroplex emission between electrons and holes is a reason for the low turn-on voltage of the GO-CoTPP-based OLED. Maximum luminance efficiency of 1.43 cd/A with Commission International de l'Eclairage coordinates of 0.33 and 0.40 was achieved at current of 0.02 mA and voltage of 14 V.

Synthesis and electroluminescent properties of anthracene derivatives containing electron-withdrawing oxide moieties

Energy Technology Data Exchange (ETDEWEB)

Yoon, Jhin-yeong; Na, Eun Jae; Park, Soo Na [Department of Chemistry, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Lee, Seok Jae [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of); Kim, Young Kwan, E-mail: kimyk@wow.hongik.ac.kr [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of); Yoon, Seung Soo, E-mail: ssyoon@skku.edu [Department of Chemistry, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of)

2014-10-15

Highlights: • Blue fluorescent material is important for application in full-color displays. • We have synthesized emitters based on anthracene connected with oxide moieties. • 1C shows a highly efficient blue EL emission due to electron-injection property. - Abstract: A series of new blue-emitting materials: (4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)(phenyl)methanone (1); 9-(naphthalen-2-yl)-10-(4-((diphenyl)phosphine oxide)phenyl)anthracene (2); 9-(naphthalen-2-yl)-10-(4-(phenylsulfonyl)phenyl)anthracene (3) were designed and synthesized via Suzuki cross-coupling reaction. Multilayer OLEDs were fabricated in the following sequence: ITO (180 nm)/NPB (50 nm)/blue materials 1–3 (30 nm)/TPBi (15 nm)/Liq (2 nm)/Al (100 nm). All devices showed the efficient blue EL emissions. In particular, the device using 1 as an emitter exhibited efficient blue electroluminescent properties with a maximum luminous, power, external quantum efficiency and CIE coordinates of 0.36 cd/A, 0.90 lm/W, 0.55% at 20 mA/cm{sup 2} and (x = 0.16, y = 0.20) at 10.0 V, respectively.

Efficiency criterion for teleportation via channel matrix, measurement matrix and collapsed matrix

Directory of Open Access Journals (Sweden)

Xin-Wei Zha

Full Text Available In this paper, three kinds of coefficient matrixes (channel matrix, measurement matrix, collapsed matrix associated with the pure state for teleportation are presented, the general relation among channel matrix, measurement matrix and collapsed matrix is obtained. In addition, a criterion for judging whether a state can be teleported successfully is given, depending on the relation between the number of parameter of an unknown state and the rank of the collapsed matrix. Keywords: Channel matrix, Measurement matrix, Collapsed matrix, Teleportation

Active matrix metalloproteases are expressed early on and are high during the Barrett's esophagus malignancy sequence

NARCIS (Netherlands)

Davelaar, Akueni L.; Straub, Daniëlle; Buttar, Navtej S.; Fockens, Paul; Krishnadath, Kausilia K.

2015-01-01

Objective. Molecular processes underlying Barrett's malignant development are poorly understood. Matrix metalloproteases (MMPs) are enzymes involved in inflammation, tissue remodeling, and malignant development. Therefore, active MMPs may have a role in early metaplasia development and Barrett's

Electroluminescence enhancement for near-ultraviolet light emitting diodes with graphene/AZO-based current spreading layers

DEFF Research Database (Denmark)

Lin, Li; Ou, Yiyu; Zhu, Xiaolong

LEDs) have attracted significant research interest due to their intensive applications in various areas where indium tin oxide (ITO) is one of the most widely employed transparent conductive materials for NUV LEDs. Compared to ITO, indium-free aluminum-doped zinc oxide (AZO) has similar electrical......Near-ultraviolet light emitting diodes with different aluminum-doped zinc oxide-based current spreading layers were fabricated and electroluminescence (EL) was compared. A 170% EL enhancement was achieved by using a graphene-based interlayer. GaN-based near-ultraviolet light emitting diodes (NUV...... with a new type of current spreading layer (CSL) which combines AZO and a single-layer graphene (SLG) as an effective transparent CSL [1]. In the present work, LEDs with solo AZO CSL in Fig.1(a) and SLG/Ni/AZO-based CSL in Fig.1(b) were both fabricated for EL comparison. Standard mesa fabrication including...

Tissue- and Cell-Specific Co-localization of Intracellular Gelatinolytic Activity and Matrix Metalloproteinase 2

Science.gov (United States)

Solli, Ann Iren; Fadnes, Bodil; Winberg, Jan-Olof; Uhlin-Hansen, Lars

2013-01-01

Matrix metalloproteinase 2 (MMP-2) is a proteolytic enzyme that degrades extracellular matrix proteins. Recent studies indicate that MMP-2 also has a role in intracellular proteolysis during various pathological conditions, such as ischemic injuries in heart and brain and in tumor growth. The present study was performed to map the distribution of intracellular MMP-2 activity in various mouse tissues and cells under physiological conditions. Samples from normal brain, heart, lung, liver, spleen, pancreas, kidney, adrenal gland, thyroid gland, gonads, oral mucosa, salivary glands, esophagus, intestines, and skin were subjected to high-resolution in situ gelatin zymography and immunohistochemical staining. In hepatocytes, cardiac myocytes, kidney tubuli cells, epithelial cells in the oral mucosa as well as in excretory ducts of salivary glands, and adrenal cortical cells, we found strong intracellular gelatinolytic activity that was significantly reduced by the metalloprotease inhibitor EDTA but not by the cysteine protease inhibitor E-64. Furthermore, the gelatinolytic activity was co-localized with MMP-2. Western blotting and electron microscopy combined with immunogold labeling revealed the presence of MMP-2 in different intracellular compartments of isolated hepatocytes. Our results indicate that MMP-2 takes part in intracellular proteolysis in specific tissues and cells during physiological conditions. PMID:23482328

Atmospheric-Pressure Cold Plasmas Used to Embed Bioactive Compounds in Matrix Material for Active Packaging of Fruits and Vegetables

Science.gov (United States)

Fernandez, Sulmer; Pedrow, Patrick; Powers, Joseph; Pitts, Marvin

2009-10-01

Active thin film packaging is a technology with the potential to provide consumers with new fruit and vegetable products-if the film can be applied without deactivating bioactive compounds.Atmospheric pressure cold plasma (APCP) processing can be used to activate monomer with concomitant deposition of an organic plasma polymerized matrix material and to immobilize a bioactive compound all at or below room temperature.Aims of this work include: 1) immobilize an antimicrobial in the matrix; 2) determine if the antimicrobial retains its functionality and 3) optimize the reactor design.The plasma zone will be obtained by increasing the voltage on an electrode structure until the electric field in the feed material (argon + monomer) yields electron avalanches. Results will be described using Red Delicious apples.Prospective matrix precursors are vanillin and cinnamic acid.A prospective bioactive compound is benzoic acid.

Buddleja officinalis inhibits high glucose-induced matrix metalloproteinase activity in human umbilical vein endothelial cells.

Science.gov (United States)

Lee, Yun Jung; Kang, Dae Gill; Kim, Jin Sook; Lee, Ho Sub

2008-12-01

The aim of the present investigation was to investigate whether an aqueous extract of Buddleja officinalis (ABO), a traditional Korean herbal medicine, suppresses the endothelial extracellular matrix degradation under high glucose condition. The incubation with high concentration of glucose (25 mM) increased significantly matrix metalloproteinase (MMP)-2/-9 expressions and activities in primary cultured human umbilical vein endothelial cells (HUVEC). Pretreatment with ABO decreased high glucose-induced increase of MMP-2/-9 activities in a dose-dependent manner. Real time qRT-PCR revealed that high glucose-induced MMP-2/-9 mRNA expression levels were attenuated by pretreatment with ABO. High glucose-induced MCP-1 and IL-8 mRNA expression levels also decreased by ABO. ABO decreased high glucose-induced hydrogen peroxide production, oxidative stress marker. These results provide new insights into the pathophysiological mechanisms for anti-inflammatory properties of ABO in vascular diseases associated with diabetes mellitus. (c) 2008 John Wiley & Sons, Ltd.

Large-Area High-Performance Flexible Pressure Sensor with Carbon Nanotube Active Matrix for Electronic Skin.

Science.gov (United States)

Nela, Luca; Tang, Jianshi; Cao, Qing; Tulevski, George; Han, Shu-Jen

2018-03-14

Artificial "electronic skin" is of great interest for mimicking the functionality of human skin, such as tactile pressure sensing. Several important performance metrics include mechanical flexibility, operation voltage, sensitivity, and accuracy, as well as response speed. In this Letter, we demonstrate a large-area high-performance flexible pressure sensor built on an active matrix of 16 × 16 carbon nanotube thin-film transistors (CNT TFTs). Made from highly purified solution tubes, the active matrix exhibits superior flexible TFT performance with high mobility and large current density, along with a high device yield of nearly 99% over 4 inch sample area. The fully integrated flexible pressure sensor operates within a small voltage range of 3 V and shows superb performance featuring high spatial resolution of 4 mm, faster response than human skin (<30 ms), and excellent accuracy in sensing complex objects on both flat and curved surfaces. This work may pave the road for future integration of high-performance electronic skin in smart robotics and prosthetic solutions.

Photorefractive keratectomy: measuring the matrix metalloproteinase activity and chondroitin sulfate concentration in tear fluid

Directory of Open Access Journals (Sweden)

Tetsuya Mutoh

2010-09-01

Full Text Available Tetsuya Mutoh, Masaya Nishio, Yukihiro Matsumoto, Kiyomi Arai, Makoto ChikudaDepartment of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Saitama, JapanAbstract: We herein report the case of a 20-year-old man who underwent a photorefractive keratectomy (PRK. We measured matrix metalloproteinase-9 (MMP-9 activity and chondroitin 4 sulfate and chondroitin 6 sulfate concentrations in tear fluid. Tear fluid was collected preoperatively via microcapillary tube, and was collected postoperatively on the first and fourth days, and after one week, one month, three months, and six months. Samples were formulated by dilution with 200 µL of saline. MMP-9 activity was analyzed by an enzyme immunocapture activity assay, and the concentrations of chondroitin sulfate were analyzed by enzyme-linked immunosorbent assay. No complications were observed after surgery, except for a minimal subepithelial haze. Although MMP-9 activity changed on the fourth postoperative day, the activity changed only minimally at this time. Chondroitin 4 sulfate concentrations in tear fluid increased dramatically from one week to one month, decreased transiently at three months, and increased by six months. The chondroitin 6 sulfate concentration did not normalize within one week, and decreased from one week to three months compared with the preoperative score, and was close to the preoperative score at six months. We conclude that corneal wound healing was still incomplete six months after PRK, and chondroitin 4 sulfate appears to be critical in this process.Keywords: matrix metalloproteinase, chondroitin sulfate, human tear fluid, photorefractive keratectomy, corneal wound healing

Efficient red organic electroluminescent devices based on trivalent europium complex obtained by designing the device structure with stepwise energy levels

Energy Technology Data Exchange (ETDEWEB)

Zhou, Liang; Jiang, Yunlong; Cui, Rongzhen; Li, Yanan; Zhao, Xuesen; Deng, Ruiping; Zhang, Hongjie, E-mail: hongjie@ciac.ac.cn

2016-02-15

In this study, we aim to further enhance the electroluminescence (EL) performances of trivalent europium complex Eu(TTA){sub 3}phen (TTA=thenoyltrifluoroacetone and phen=1,10-phenanthroline) by designing the device structure with stepwise energy levels. The widely used bipolar material 2,6-bis(3-(9H-carbazol-9-yl)phenyl)pyridine (26DCzPPy) was chosen as host material, while the doping concentration of Eu(TTA){sub 3}phen was optimized to be 4%. To facilitate the injection and transport of holes, MoO{sub 3} anode modification layer and 4,4′,4′′-Tris(carbazole-9-yl)triphenylamine (TcTa) hole transport layer were inserted in sequence. Efficient pure red emission with suppressed efficiency roll-off was obtained attributed to the reduction of accumulation holes, the broadening of recombination zone, and the improved balance of holes and electrons on Eu(TTA){sub 3}phen molecules. Finally, the device with 3 nm MoO{sub 3} and 5 nm TcTa obtained the highest brightness of 3278 cd/m{sup 2}, current efficiency of 12.45 cd/A, power efficiency of 11.50 lm/W, and external quantum efficiency of 6.60%. Such a device design strategy helps to improve the EL performances of emitters with low-lying energy levels and provides a chance to simplify device fabrication processes. - Highlights: • Electroluminescent performances of europium complex were further improved. • Device structure with stepwise energy levels was designed. • Better carriers' balance was realized by improving the injection and transport of holes. • The selection of bipolar host caused the broadening of recombination zone.

Study of structural, morphological, optical and electroluminescent properties of undoped ZnO nanorods grown by a simple chemical precipitation

Directory of Open Access Journals (Sweden)

Singh A.

2015-12-01

Full Text Available In this work, zinc oxide (ZnO nanorods were obtained by a simple chemical precipitation method in the presence of capping agent: polyvinyl pyrrolidone (PVP at room temperature. X-ray diffraction (XRD result indicates that the synthesized undoped ZnO nanorods have hexagonal wurtzite structure without any impurities. It has been observed that the growth direction of the prepared ZnO nanorods is [1 0 1]. XRD analysis revealed that the nanorods have the crystallite size of 49 nm. Crystallite size is calculated by Debye-Scherrer formula and lattice strain is calculated by Williomson-Hall equation. Cell volume, Lorentz factor, Lorentz polarization factor, bond length, texture coefficient, lattice constants and dislocation density have also been studied. We also compared the interplanar spacings and relative peak intensities with their standard values at different angles. The scanning electron microscope (SEM images confirmed the size and shape of these nanorods. It has been found that the diameter of the nanorods ranges from 1.52 μm to 1.61 μm and the length is about 4.89 μm. It has also been observed that at room temperature ultraviolet visible (UV-Vis absorption band is around 355 nm (blue shifted as compared to the bulk. The average particle size has also been calculated by mathematical model of effective mass approximation equation, using UV-Vis absorption peak. Finally, the bandgap has been calculated using UV-absorption peak. Electroluminescence (EL studies show that emission of light is possible at very small threshold voltage and it increases rapidly with increasing applied voltage. It is seen that smaller ZnO nanoparticles give higher electroluminescence brightness starting at lower threshold voltage. The brightness is also affected by increasing the frequency of AC signal.

Ulex europaeus I lectin induces activation of matrix-metalloproteinase-2 in endothelial cells.

Science.gov (United States)

Gomez, D E; Yoshiji, H; Kim, J C; Thorgeirsson, U P

1995-11-02

In this report, we show that the lectin Ulex europaeus agglutinin I (UEA I), which binds to alpha-linked fucose residues on the surface of endothelial cells, mediates activation of the 72-kDa matrix metalloproteinase-2 (MMP-2). A dose-dependent increase in the active 62-kDa form of MMP-2 was observed in conditioned medium from monkey aortic endothelial cells (MAEC) following incubation with concentrations of UEA I ranging from 2 to 100 micrograms/ml. The increase in the 62-kDa MMP-2 gelatinolytic activity was not reflected by a rise in MMP-2 gene expression. The UEA I-mediated activation of MMP-2 was blocked by L-fucose, which competes with UEA I for binding to alpha-fucose. These findings may suggest that a similar in vivo mechanism exists, whereby adhesive interactions between tumor cell lectins and endothelial cells can mediate MMP-2 activation.

Atypical protein kinase C activity is required for extracellular matrix degradation and invasion by Src-transformed cells.

Science.gov (United States)

Rodriguez, Elena M; Dunham, Elizabeth E; Martin, G Steven

2009-10-01

Atypical protein kinase C (aPKC) isoforms have been shown to mediate Src-dependent signaling in response to growth factor stimulation. To determine if aPKC activity contributes to the transformed phenotype of cells expressing oncogenic Src, we have examined the activity and function of aPKCs in 3T3 cells expressing viral Src (v-Src). aPKC activity and tyrosine phosphorylation were found to be elevated in some but not all clones of mouse fibroblasts expressing v-Src. aPKC activity was inhibited either by addition of a membrane-permeable pseudosubstrate, by expression of a dominant-negative aPKC, or by RNAi-mediated knockdown of specific aPKC isoforms. aPKC activity contributes to morphological transformation and stress fiber disruption, and is required for migration of Src-transformed cells and for their ability to polarize at the edge of a monolayer. The lambda isoform of aPKC is specifically required for invasion through extracellular matrix in Boyden chamber assays and for degradation of the extracellular matrix in in situ zymography assays. Tyrosine phosphorylation of aPKClambda is required for its ability to promote cell invasion. The defect in invasion upon aPKC inhibition appears to result from a defect in the assembly and/or function of podosomes, invasive adhesions on the ventral surface of the cell that are sites of protease secretion. aPKC was also found to localize to podosomes of v-Src transformed cells, suggesting a direct role for aPKC in podosome assembly and/or function. We conclude that basal or elevated aPKC activity is required for the ability of Src-transformed cells to degrade and invade the extracellular matrix. Copyright 2009 Wiley-Liss, Inc.

Matrix Metalloproteinase Activity in Infections by an Encephalitic Virus, Mouse Adenovirus Type 1

Science.gov (United States)

Ashley, Shanna L.; Pretto, Carla D.; Stier, Matthew T.; Kadiyala, Padma; Castro-Jorge, Luiza; Hsu, Tien-Huei; Doherty, Robert; Carnahan, Kelly E.; Castro, Maria G.; Lowenstein, Pedro R.

2017-01-01

ABSTRACT Mouse adenovirus type 1 (MAV-1) infection causes encephalitis in susceptible strains of mice and alters the permeability of infected brains to small molecules, which indicates disruption of the blood-brain barrier (BBB). Under pathological conditions, matrix metalloproteinases (MMPs) can disrupt the BBB through their proteolytic activity on basement membrane and tight junction proteins. We examined whether MAV-1 infection alters MMP activity in vivo and in vitro. Infected MAV-1-susceptible SJL mice had higher MMP2 and MMP9 activity in brains, measured by gelatin zymography, than mock-infected mice. Infected MAV-1-resistant BALB/c mice had MMP activity levels equivalent to those in mock infection. Primary SJL mouse brain endothelial cells (a target of MAV-1 in vivo) infected ex vivo with MAV-1 had no difference in activities of secreted MMP2 and MMP9 from mock cells. We show for the first time that astrocytes and microglia are also infected in vivo by MAV-1. Infected mixed primary cultures of astrocytes and microglia had higher levels of MMP2 and MMP9 activity than mock-infected cells. These results indicate that increased MMP activity in the brains of MAV-1-infected susceptible mice may be due to MMP activity produced by endothelial cells, astrocytes, and microglia, which in turn may contribute to BBB disruption and encephalitis in susceptible mice. IMPORTANCE RNA and DNA viruses can cause encephalitis; in some cases, this is accompanied by MMP-mediated disruption of the BBB. Activated MMPs degrade extracellular matrix and cleave tight-junction proteins and cytokines, modulating their functions. MAV-1 infection of susceptible mice is a tractable small-animal model for encephalitis, and the virus causes disruption of the BBB. We showed that MAV-1 infection increases enzymatic activity of two key MMPs known to be secreted and activated in neuroinflammation, MMP2 and MMP9, in brains of susceptible mice. MAV-1 infects endothelial cells, astrocytes, and

Neutron activation of chlorine in zirconium and zirconium alloys use of the matrix as comparator

International Nuclear Information System (INIS)

Cohen, I.M.; Gomez, C.D.; Mila, M.I.

1981-01-01

A procedure is described for neutron activation analysis of chlorine in zirconium and zirconium alloys. Calculation of chlorine concentration is performed relative to zirconium concentration in the matrix in order to minimize effects of differences in irradiation and counting geometry. Principles of the method and the results obtained are discussed. (author)

Bidirectional electroluminescence from p-SnO2/i-MgZnO/n-ZnO heterojunction light-emitting diodes

International Nuclear Information System (INIS)

Yang, Yanqin; Li, Songzhan; Liu, Feng; Zhang, Nangang; Liu, Kan; Wang, Shengxiang; Fang, Guojia

2017-01-01

Light-emitting diodes based on p-SnO 2 /i-MgZnO/n-ZnO heterojunction have been fabricated. The material properties and the performance of heterojunction device are characterized. Current-voltage characteristics of the device show a diode-like rectifying behavior. Under forward bias, two prominent emission peaks located at 589 nm and 722 nm in the visible region and a weak ultraviolet emission are observed from p-SnO 2 /i-MgZnO/n-ZnO heterojunction device. As the device is under reverse bias, a broad visible emission band dominates the electroluminescence spectrum at a high current. Furthermore, the emission mechanism has been discussed in terms of energy band structures of the device under forward and reverse biases.

Food matrix and processing influence on carotenoid bioaccessibility and lipophilic antioxidant activity of fruit juice-based beverages.

Science.gov (United States)

Rodríguez-Roque, María Janeth; de Ancos, Begoña; Sánchez-Vega, Rogelio; Sánchez-Moreno, Concepción; Cano, M Pilar; Elez-Martínez, Pedro; Martín-Belloso, Olga

2016-01-01

The biological activity of carotenoids depends on their bioaccessibility and solubilization in the gastrointestinal tract. These compounds are poorly dispersed in the aqueous media of the digestive tract due to their lipophilic nature. Thus, it is important to analyze the extent to which some factors, such as the food matrix and food processing, may improve their bioaccessibility. Beverages formulated with a blend of fruit juices and water (WB), milk (MB) or soymilk (SB) were treated by high-intensity pulsed electric fields (HIPEF) (35 kV cm(-1) with 4 μs bipolar pulses at 200 Hz for 1800 μs), high-pressure processing (HPP) (400 MPa at 40 °C for 5 min) or thermal treatment (TT) (90 °C for 1 min) in order to evaluate the influence of food matrix and processing on the bioaccessibility of carotenoids and on the lipophilic antioxidant activity (LAA). The bioaccessibility of these compounds diminished after applying any treatment (HIPEF, HPP and TT), with the exception of cis-violaxanthin + neoxanthin, which increased by 79% in HIPEF and HPP beverages. The lowest carotenoid bioaccessibility was always obtained in TT beverages (losses up to 63%). MB was the best food matrix for improving the bioaccessibility of carotenoids, as well as the LAA. The results demonstrate that treatment and food matrix modulated the bioaccessibility of carotenoids as well as the lipophilic antioxidant potential of beverages. Additionally, HIPEF and HPP could be considered as promising technologies to obtain highly nutritional and functional beverages.

Immobilization of cellulase using porous polymer matrix

International Nuclear Information System (INIS)

Kumakura, M.; Kaetsu, I.

1984-01-01

A new method is discussed for the immobilization of cellulase using porous polymer matrices, which were obtained by radiation polymerization of hydrophilic monomers. In this method, the immobilized enzyme matrix was prepared by enzyme absorbtion in the porous polymer matrix and drying treatment. The enzyme activity of the immobilized enzyme matrix varied with monomer concentration, cooling rate of the monomer solution, and hydrophilicity of the polymer matrix, takinn the change of the nature of the porous structure in the polymer matrix. The leakage of the enzymes from the polymer matrix was not observed in the repeated batch enzyme reactions

Acrolein-activated matrix metalloproteinase 9 contributes to persistent mucin production.

Science.gov (United States)

Deshmukh, Hitesh S; Shaver, Colleen; Case, Lisa M; Dietsch, Maggie; Wesselkamper, Scott C; Hardie, William D; Korfhagen, Thomas R; Corradi, Massimo; Nadel, Jay A; Borchers, Michael T; Leikauf, George D

2008-04-01

Chronic obstructive pulmonary disease (COPD), a global public health problem, is characterized by progressive difficulty in breathing, with increased mucin production, especially in the small airways. Acrolein, a constituent of cigarette smoke and an endogenous mediator of oxidative stress, increases airway mucin 5, subtypes A and C (MUC5AC) production; however, the mechanism remains unclear. In this study, increased mMUC5AC transcripts and protein were associated with increased lung matrix metalloproteinase 9 (mMMP9) transcripts, protein, and activity in acrolein-exposed mice. Increased mMUC5AC transcripts and mucin protein were diminished in gene-targeted Mmp9 mice [Mmp9((-/-))] or in mice treated with an epidermal growth factor receptor (EGFR) inhibitor, erlotinib. Acrolein also decreased mTissue inhibitor of metalloproteinase protein 3 (an MMP9 inhibitor) transcript levels. In a cell-free system, acrolein increased pro-hMMP9 cleavage and activity in concentrations (100-300 nM) found in sputum from subjects with COPD. Acrolein increased hMMP9 transcripts in human airway cells, which was inhibited by an MMP inhibitor, EGFR-neutralizing antibody, or a mitogen-activated protein kinase (MAPK) 3/2 inhibitor. Together these findings indicate that acrolein can initiate cleavage of pro-hMMP9 and EGFR/MAPK signaling that leads to additional MMP9 formation. Augmentation of hMMP9 activity, in turn, could contribute to persistent excessive mucin production.

How to get the Matrix Organization to Work

DEFF Research Database (Denmark)

Burton, Richard M.; Obel, Børge; Håkonsson, Dorthe Døjbak

2015-01-01

a matrix to work, taking a multi-contingency perspective. We translate the matrix concept for designers and managers who are considering a matrix organization and argue that three factors are critical for its success: (1) Strong purpose: Only choose the matrix structure if there are strong reasons...... for doing so, (2) Alignment among contingencies: A matrix can only be successful if key contingencies are aligned with the matrix’s purpose, and (3) Management of junctions: The success of a matrix depends on how well activities at the junctions of the matrix are managed....

Matrix Metalloproteinases in Non-Neoplastic Disorders

Science.gov (United States)

Tokito, Akinori; Jougasaki, Michihisa

2016-01-01

The matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases belonging to the metzincin superfamily. There are at least 23 members of MMPs ever reported in human, and they and their substrates are widely expressed in many tissues. Recent growing evidence has established that MMP not only can degrade a variety of components of extracellular matrix, but also can cleave and activate various non-matrix proteins, including cytokines, chemokines and growth factors, contributing to both physiological and pathological processes. In normal conditions, MMP expression and activity are tightly regulated via interactions between their activators and inhibitors. Imbalance among these factors, however, results in dysregulated MMP activity, which causes tissue destruction and functional alteration or local inflammation, leading to the development of diverse diseases, such as cardiovascular disease, arthritis, neurodegenerative disease, as well as cancer. This article focuses on the accumulated evidence supporting a wide range of roles of MMPs in various non-neoplastic diseases and provides an outlook on the therapeutic potential of inhibiting MMP action. PMID:27455234

Effect Of Neutron Activation Factor On The Physico-Chemical Properties Of Hydrophilic And Hydrophobic Polymer Formulation Of Matrix Tablets

International Nuclear Information System (INIS)

Ibrahim Ijang; Bohari Yaacob; Nordiana, N.R.

2011-01-01

This study was to investigate effect of neutron activation on the physicochemical properties and in vitro dissolution of sustained-release matrix tablets. The tablets incorporation of Samarium oxide (Sm 2 O 3 ) and were compared before and after irradiation with thermal neutron for 5 minutes at 1.2 x 10 12 neutron cm -2 s -1 . The neutron activation factor did not influence the compression properties of the tablets. The dissolution tests showed that irradiation increased the release of the model drug ketoprofen from the tablets. This effect might be explained by polymer degradation. Incorporation of Sm 2 O 3 in the matrix tablets did not influence the release. (author)

Origin of the Electroluminescence from Annealed-ZnO/GaN Heterojunction Light-Emitting Diodes

Directory of Open Access Journals (Sweden)

Kai-Chiang Hsu

2015-11-01

Full Text Available This paper addressed the effect of post-annealed treatment on the electroluminescence (EL of an n-ZnO/p-GaN heterojunction light-emitting diode (LED. The bluish light emitted from the 450 °C-annealed LED became reddish as the LED annealed at a temperature of 800 °C under vacuum atmosphere. The origins of the light emission for these LEDs annealed at various temperatures were studied using measurements of electrical property, photoluminescence, and Auger electron spectroscopy (AES depth profiles. A blue-violet emission located at 430 nm was associated with intrinsic transitions between the bandgap of n-ZnO and p-GaN, the green-yellow emission at 550 nm mainly originating from the deep-level transitions of native defects in the n-ZnO and p-GaN surfaces, and the red emission at 610 nm emerging from the Ga-O interlayer due to interdiffusion at the n-ZnO/p-GaN interface. The above-mentioned emissions also supported the EL spectra of LEDs annealed at 700 °C under air, nitrogen, and oxygen atmospheres, respectively.

White electroluminescence from ZnO nanorods/p-GaN heterojunction light-emitting diodes under reverse bias

International Nuclear Information System (INIS)

Zhang, Lichun; Li, Qingshan; Qu, Chong; Zhang, Zhongjun; Huang, Ruizhi; Zhao, Fengzhou

2013-01-01

Heterojunction light-emitting diodes (LEDs) based on arrays of ZnO nanorods were fabricated on p-GaN films by the hydrothermal method. Without any phosphors, white-light electroluminescence (EL) from ZnO nanorods/p-GaN heterojunction LEDs operated at reverse breakdown bias was observed. The EL spectra are composed of an ultraviolet (UV) emission centered at 382 nm, a blue light located at 431 nm and a broadband yellow–green light at around 547 nm, which originated from band-edge emission in ZnO, the Mg acceptor levels in p-GaN and the deep-level states near the ZnO/GaN interface, respectively. The chromaticity coordinates of EL spectrum are very close to the (0.333, 0.333) of standard white light. The origin of these emissions has been discussed and the tunneling effect in the interface is probably the mechanism to explain EL emission. (paper)

Enhanced phosphorescence and electroluminescence in triplet emitters by doping gold into cadmium selenide/zinc sulfide nanoparticles

International Nuclear Information System (INIS)

Liu, H.-W.; Laskar, Inamur R.; Huang, C.-P.; Cheng, J.-A.; Cheng, S.-S.; Luo, L.-Y.; Wang, H.-R.; Chen, T.-M.

2005-01-01

Gold-cadmium selenide/zinc sulfide (Au-CdSe/ZnS) nanocomposites (NCs) were synthesized and characterized by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, ultraviolet-visible (UV-visible) absorption and photoluminescence (PL) emission spectroscopy. The PL intensity in the Au-CdSe/ZnS NCs system was found to be much greater than that of CdSe/ZnS nanoparticles (NPs) alone, because of the surface-enhanced Raman scattering of Au NPs. Adding Au-CdSe/ZnS NCs to the cyclometalated iridium(III) complex (Ir-complex) greatly enhanced the PL intensity of a triplet emitter. Three double-layered electroluminescence (EL) devices were fabricated where the emitting zone contains the definite mixture of Ir-complex and the NCs [molar concentration of Ir-complex/NCs = 1:0 (Blank, D-1), 1:1 (D-2) and 1:3 (D-3)] and the device D-2 exhibited optimal EL performances

Luminance and image quality analysis of an organic electroluminescent panel with a patterned microlens array attachment

International Nuclear Information System (INIS)

Lin, Hoang Yan; Chen, Kuan-Yu; Ho, Yu-Hsuan; Fang, Jheng-Hao; Hsu, Sheng-Chih; Lee, Jiun-Haw; Lin, Jia-Rong; Wei, Mao-Kuo

2010-01-01

Luminance and image quality observed from the normal direction of a commercial 2.0 inch panel based on organic electroluminescence (OEL) technology attached to regular and patterned microlens array films (MAFs) were studied and analyzed. When applying the regularly arranged MAF on the panel, a luminance enhancement of 23% was observed, accompanied by a reduction of the image quality index as low as 74%. By removing the microlenses on the emitting areas, the patterned MAF enhances the luminance efficiency of the OEL by 52% keeping the image quality index of the display as high as 94%, due to the effective light extraction in the glass substrate being less than the critical angle. 3D simulation based on a ray-tracing model was also established to investigate the spatial distribution of light rays radiated from an OEL pixel with different microstructures which showed consistent results with the experimental results

Synthesis, structures and electroluminescence properties of CdS:In/Si nanoheterostructure array

Energy Technology Data Exchange (ETDEWEB)

Yan, Ling Ling; Cai, Hong Xin; Chen, Liang [Henan Polytechnic University, School of Physics and Electronic Information Engineering, Jiaozuo (China)

2017-10-15

An In-doped CdS/Si nanoheterojunction (CdS:In/Si-NPA) is prepared by depositing an In-doped CdS thin film onto a Si nanoporous pillar array (Si-NPA) via a successive ionic layer adsorption and reaction method. Based on the measured J-V characteristic curve, the nanoheterojunction exhibits a good rectifying behavior with a low forward turn-on voltage (2.2 V), a small leakage current density (0.5 mA/cm{sup 2} at - 3 V) and a high reverse breakdown voltage (> 8 V). The electroluminescence (EL) measurements reveal that a broadband emerges between 400 and 700 nm, and this band is confirmed as a white light emission based on the value of the chromaticity coordinate. The EL properties, including the CIE chromaticity coordinates, Colour Rendering Index and correlated color temperature, can be tuned by the applied voltage. The generation mechanism of the EL can be well interpreted depending on the energy band structure of CdS:In/Si-NPA. The green band should be attributed to the band-edge emission of CdS and the yellow emission may be related to Cd interstitial. These results highlight the potential of CdS:In/Si-NPA as a light source for future white light emitting devices. (orig.)

Direct Vapor Growth of Perovskite CsPbBr3 Nanoplate Electroluminescence Devices.

Science.gov (United States)

Hu, Xuelu; Zhou, Hong; Jiang, Zhenyu; Wang, Xiao; Yuan, Shuangping; Lan, Jianyue; Fu, Yongping; Zhang, Xuehong; Zheng, Weihao; Wang, Xiaoxia; Zhu, Xiaoli; Liao, Lei; Xu, Gengzhao; Jin, Song; Pan, Anlian

2017-10-24

Metal halide perovskite nanostructures hold great promises as nanoscale light sources for integrated photonics due to their excellent optoelectronic properties. However, it remains a great challenge to fabricate halide perovskite nanodevices using traditional lithographic methods because the halide perovskites can be dissolved in polar solvents that are required in the traditional device fabrication process. Herein, we report single CsPbBr 3 nanoplate electroluminescence (EL) devices fabricated by directly growing CsPbBr 3 nanoplates on prepatterned indium tin oxide (ITO) electrodes via a vapor-phase deposition. Bright EL occurs in the region near the negatively biased contact, with a turn-on voltage of ∼3 V, a narrow full width at half-maximum of 22 nm, and an external quantum efficiency of ∼0.2%. Moreover, through scanning photocurrent microscopy and surface electrostatic potential measurements, we found that the formation of ITO/p-type CsPbBr 3 Schottky barriers with highly efficient carrier injection is essential in realizing the EL. The formation of the ITO/p-type CsPbBr 3 Schottky diode is also confirmed by the corresponding transistor characteristics. The achievement of EL nanodevices enabled by directly grown perovskite nanostructures could find applications in on-chip integrated photonics circuits and systems.

Curcumin influences hepatic expression patterns of matrix metalloproteinases in liver toxicity.

Science.gov (United States)

Rukkumani, Rajagopalan; Aruna, Kode; Varma, Penumathsa Suresh; Menon, Venugopal Padmanabhan

2004-07-01

Hepatic fibrosis is a result of an imbalance between enhanced matrix synthesis and diminished breakdown of connective tissue proteins, the net result of which is increased deposition of Extra Cellular Matrix. In this concept Matrix Metalloproteinases play an important role because their activity is largely responsible for extra cellular matrix breakdown. In the present study we have tested the influence of curcumin, the active principle of turmeric, on matrix metalloproteinase expression during alcohol and thermally oxidised sunflower oil induced liver toxicity. Male albino Wistar rats were used for the study. The matrix metalloproteinase expressions were found to be increased significantly in alcohol as well as thermally oxidised sunflower oil groups and on treatment with curcumin there was a significant decrease. In alcohol + thermally oxidised sunflower oil group, we found a significant decrease in matrix metalloproteinase activities. Administration of curcumin significantly improved their activities. From the results obtained, we could conclude that curcumin influences the hepatic matrix metalloproteinases and effectively protects liver against alcohol and delta PUFA induced toxicity.

Influence of Exciplex formation on the electroluminescent properties of dimeric Zn (II) bis-2-(2'-hydroxyphenyl) benzoxazole complex and monomeric Zn (II) 2-(1'-hydroxynaphthyl) benzothiazole complex

Science.gov (United States)

Prakash, Sattey; Anand, R. S.; Manoharan, S. Sundar

2011-10-01

In this paper we present the factors affecting electroluminescent properties of Zinc complexes of oxazole & thiazole derivatives. Electroluminescent spectra of the Zinc (II) complex of bis-[2-(2'-hydroxyphenyl) benzoxazole], [Zn (HPBO)2]2 and 2-(1'-hydroxynaphthyl) benzothiazole [Zn (HNBT)2] show unusual broadening and shows structural and photophysical similarity with [Zn (HPBT)2]2, a dimeric complex. The [Zn (HPBO)2]2 complex as an emissive layer in the device structure ITO /PEDOT:PSS /TPD (30nm) /[Zn (HPBO)2]2 (60nm) /BCP (6nm) /Ca (3nm) /Al (200nm) shows a broad bluish green emission, with a full width at half maxima (FWHM1˜70nm). The EL spectra is much broader compared to the PL spectra because of exciplex formation at the interfacial region between the emissive layer (EML) & hole transport layer (HTL). We also show the device performance of Zinc 2-(1'-hydroxynaphthyl) benzothiazole [Zn (HNBT)2] complex as emissive layer. Distinctly this device shows a broad greenish yellow emission with a peak maxima at 535nm and 690nm, owing to the exciplex formation between electron transport layer (ETL) and emissive layer (EML), which is in sharp contrast to the exciplex formation across the HTL-EML interface observed for the [Zn (HPBO)2]2 complex.

Strategy BMT Al-Ittihad Using Matrix IE, Matrix SWOT 8K, Matrix SPACE and Matrix TWOS

Directory of Open Access Journals (Sweden)

Nofrizal Nofrizal

2018-03-01

Full Text Available This research aims to formulate and select BMT Al-Ittihad Rumbai strategy to face the changing of business environment both from internal environment such as organization resources, finance, member and external business such as competitor, economy, politics and others. This research method used Analysis of EFAS, IFAS, IE Matrix, SWOT-8K Matrix, SPACE Matrix and TWOS Matrix. our hope from this research it can assist BMT Al-Ittihad in formulating and selecting strategies for the sustainability of BMT Al-Ittihad in the future. The sample in this research is using purposive sampling technique that is the manager and leader of BMT Al-IttihadRumbaiPekanbaru. The result of this research shows that the position of BMT Al-Ittihad using IE Matrix, SWOT-8K Matrix and SPACE Matrix is in growth position, stabilization and aggressive. The choice of strategy after using TWOS Matrix is market penetration, market development, vertical integration, horizontal integration, and stabilization (careful.

New copolymers with thieno[3,2-b]thiophene or dithieno[3,2-b:2',3'-d]thiophene units possessing electron-withdrawing 4-cyanophenyl groups: synthesis and photophysical, electrochemical, and electroluminescent properties

Czech Academy of Sciences Publication Activity Database

Výprachtický, Drahomír; Demirtas, I.; Dzhabarov, Vagif; Pokorná, Veronika; Ertas, E.; Ozturk, T.; Cimrová, Věra

2017-01-01

Roč. 55, č. 16 (2017), s. 2629-2638 ISSN 0887-624X R&D Projects: GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : conjugated polymers * electrochemistry * electroluminescence Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.952, year: 2016

Structural effects of a light emitting copolymer having perylene moieties in the side chain on the electroluminescent characteristics

International Nuclear Information System (INIS)

Lee, Chang Ho; Ryu, Seung Hoon; Jang, Hee Dong; Oh, Se Young

2004-01-01

We have synthesized a novel side chain light emitting copolymer. The side chain light emitting copolymer has a perylene moiety as an emitting unit and methylmethacrylate (MMA) as a spacer to decrease the concentration quenching of light emitting site in the polymer intrachain. These polymers are very soluble in most organic solvents such as monochlorobenzene, tetrahydrofuran, chloroform and benzene. The single-layered electroluminescent (EL) device consisting of ITO/carrier transporting copolymer and light emitting copolymer/Al was manufactured. The carrier transporting copolymer has triphenylamine moiety as a hole transporting unit and triazine moiety as an electron transporting unit in the polymer side chain. This device exhibits maximum external quantum efficiency when the MMA contents of light emitting copolymer is 30 wt.%. In particular, the device emits more blue light as MMA contents increase

Peroxisome proliferator-activated receptor δ inhibits Porphyromonas gingivalis lipopolysaccharide-induced activation of matrix metalloproteinase-2 by downregulating NADPH oxidase 4 in human gingival fibroblasts.

Science.gov (United States)

Yoo, T; Ham, S A; Hwang, J S; Lee, W J; Paek, K S; Oh, J W; Kim, J H; Do, J T; Han, C W; Kim, J H; Seo, H G

2016-10-01

We investigated the roles of peroxisome proliferator-activated receptor δ (PPARδ) in Porphyromonas gingivalis-derived lipopolysaccharide (Pg-LPS)-induced activation of matrix metalloproteinase 2 (MMP-2). In human gingival fibroblasts (HGFs), activation of PPARδ by GW501516, a specific ligand of PPARδ, inhibited Pg-LPS-induced activation of MMP-2 and generation of reactive oxygen species (ROS), which was associated with reduced expression of NADPH oxidase 4 (Nox4). These effects were significantly smaller in the presence of small interfering RNA targeting PPARδ or the specific PPARδ inhibitor GSK0660, indicating that PPARδ is involved in these events. In addition, modulation of Nox4 expression by small interfering RNA influenced the effect of PPARδ on MMP-2 activity, suggesting a mechanism in which Nox4-derived ROS modulates MMP-2 activity. Furthermore, c-Jun N-terminal kinase and p38, but not extracellular signal-regulated kinase, mediated PPARδ-dependent inhibition of MMP-2 activity in HGFs treated with Pg-LPS. Concomitantly, PPARδ-mediated inhibition of MMP-2 activity was associated with the restoration of types I and III collagen to levels approaching those in HGFs not treated with Pg-LPS. These results indicate that PPARδ-mediated downregulation of Nox4 modulates cellular redox status, which in turn plays a critical role in extracellular matrix homeostasis through ROS-dependent regulation of MMP-2 activity. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Direct band gap electroluminescence from bulk germanium at room temperature using an asymmetric fin type metal/germanium/metal structure

Energy Technology Data Exchange (ETDEWEB)

Wang, Dong, E-mail: wang.dong.539@m.kyushu-u.ac.jp; Maekura, Takayuki; Kamezawa, Sho [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Yamamoto, Keisuke; Nakashima, Hiroshi [Art, Science and Technology Center for Cooperative Research, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)

2015-02-16

We demonstrated direct band gap (DBG) electroluminescence (EL) at room temperature from n-type bulk germanium (Ge) using a fin type asymmetric lateral metal/Ge/metal structure with TiN/Ge and HfGe/Ge contacts, which was fabricated using a low temperature (<400 °C) process. Small electron and hole barrier heights were obtained for TiN/Ge and HfGe/Ge contacts, respectively. DBG EL spectrum peaked at 1.55 μm was clearly observed even at a small current density of 2.2 μA/μm. Superlinear increase in EL intensity was also observed with increasing current density, due to superlinear increase in population of elections in direct conduction band. The efficiency of hole injection was also clarified.

Charge-trapping effect of doped fluorescent dye on the electroluminescent processes and its performance in polymer light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Ye Tengling; Chen Zhenyu; Chen Jiangshan [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022 (China); Ma Dongge, E-mail: mdg1014@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022 (China)

2010-11-15

We have measured the temperature dependence of the steady-state current-voltage (I-V) characteristics and the transient electroluminescent (EL) characteristics in 4-(dicyanomethylene)-2-t-propyl-6-(1,1,7, 7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) doped polyfluorene devices to study the charge-trapping effect of DCJTB fluorescent dye on luminescence processes and on device performance. Physical and chemical analyses prove that DCJTB molecules serve both as electron and hole traps, and the charge-trapping effect is more sensitive against the electrons than the holes at the low dopant concentration. This intrinsic characteristic causes the electron to be injected into the emitting layer first and then trapped in the bulk, producing a strong effect on device performance.

Bidirectional electroluminescence from p-SnO{sub 2}/i-MgZnO/n-ZnO heterojunction light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Yang, Yanqin [School of Electronic and Electrical Engineering, Hubei Collaborative Innovation Center of Textile Industrial Chain Generic Technology, Wuhan Textile University, Wuhan 430073 (China); Li, Songzhan, E-mail: liszhan@whu.edu.cn [School of Electronic and Electrical Engineering, Hubei Collaborative Innovation Center of Textile Industrial Chain Generic Technology, Wuhan Textile University, Wuhan 430073 (China); Key Lab of Artificial Micro- and Nano-Structures of Ministry of Education of China, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Liu, Feng; Zhang, Nangang; Liu, Kan [School of Electronic and Electrical Engineering, Hubei Collaborative Innovation Center of Textile Industrial Chain Generic Technology, Wuhan Textile University, Wuhan 430073 (China); Wang, Shengxiang, E-mail: sxwang@wtu.edu.cn [School of Electronic and Electrical Engineering, Hubei Collaborative Innovation Center of Textile Industrial Chain Generic Technology, Wuhan Textile University, Wuhan 430073 (China); Fang, Guojia [Key Lab of Artificial Micro- and Nano-Structures of Ministry of Education of China, School of Physics and Technology, Wuhan University, Wuhan 430072 (China)

2017-06-15

Light-emitting diodes based on p-SnO{sub 2}/i-MgZnO/n-ZnO heterojunction have been fabricated. The material properties and the performance of heterojunction device are characterized. Current-voltage characteristics of the device show a diode-like rectifying behavior. Under forward bias, two prominent emission peaks located at 589 nm and 722 nm in the visible region and a weak ultraviolet emission are observed from p-SnO{sub 2}/i-MgZnO/n-ZnO heterojunction device. As the device is under reverse bias, a broad visible emission band dominates the electroluminescence spectrum at a high current. Furthermore, the emission mechanism has been discussed in terms of energy band structures of the device under forward and reverse biases.

MT1-MMP promotes cell growth and ERK activation through c-Src and paxillin in three-dimensional collagen matrix

International Nuclear Information System (INIS)

Takino, Takahisa; Tsuge, Hisashi; Ozawa, Terumasa; Sato, Hiroshi

2010-01-01

Membrane-type 1 matrix metalloproteinase (MT1-MMP) is essential for tumor invasion and growth. We show here that MT1-MMP induces extracellular signal-regulated kinase (ERK) activation in cancer cells cultured in collagen gel, which is indispensable for their proliferation. Inhibition of MT1-MMP by MMP inhibitor or small interfering RNA suppressed activation of focal adhesion kinase (FAK) and ERK in MT1-MMP-expressing cancer cells, which resulted in up-regulation of p21 WAF1 and suppression of cell growth in collagen gel. Cell proliferation was also abrogated by the inhibitor against ERK pathway without affecting FAK phosphorylation. MT1-MMP and integrin α v β 3 were shown to be involved in c-Src activation, which induced FAK and ERK activation in collagen gel. These MT1-MMP-mediated signal transductions were paxillin dependent, as knockdown of paxillin reduced cell growth and ERK activation, and co-expression of MT1-MMP with paxillin induced ERK activation. The results suggest that MT1-MMP contributes to proliferation of cancer cells in the extracellular matrix by activating ERK through c-Src and paxillin.

Optical Imaging of Matrix Metalloproteinase-7 Activity in Vivo Using a Proteolytic Nanobeacon

Directory of Open Access Journals (Sweden)

Randy L. Scherer

2008-05-01

Full Text Available Matrix metalloproteinases (MMPs are extracellular proteolytic enzymes involved in tumor progression. We present the in vivo detection and quantitation of MMP7 activity using a specific near-infrared polymer-based proteolytic beacon, PB-M7NIR. PB-M7NIR is a pegylated polyamidoamine PAMAM-Generation 4 dendrimer core covalently coupled to a Cy5.5-labeled peptide representing a selective substrate that monitors MMP7 activity (sensor and AF750 as an internal reference to monitor relative substrate concentration (reference. In vivo imaging of tumors expressing MMP7 had a median sensor to reference ratio 2.2-fold higher than a that of a bilateral control tumor. Ex vivo imaging of intestines of multiple intestinal neoplasia (APCMin mice injected systemically with PB-M7NIR revealed a sixfold increase in the sensor to reference ratio in the adenomas of APCMin mice compared with control intestinal tissue or adenomas from MMP7-null Min mice. PB-M7NIR detected tumor sizes as small as 0.01 cm2, and the sensor to reference ratio was independent of tumor size. Histologic sectioning of xenograft tumors localized the proteolytic signal to the extracellular matrix; MMP7-overexpressing tumors displayed an approximately 300-fold enhancement in the sensor to reference ratio compared with nonexpressing tumor cells. In APCMin adenomas, the proteolytic signal colocalized with the endogenously expressed MMP7 protein, with sensor to reference ratios approximately sixfold greater than that of normal intestinal epithelium. PB-M7NIR provides a useful reagent for the in vivo and ex vivo quantitation and localization of MMP-selective proteolytic activity.

A novel assay for extracellular matrix remodeling associated with liver fibrosis

DEFF Research Database (Denmark)

Barascuk, N; Veidal, S S; Larsen, L

2010-01-01

Accumulation of extracellular matrix (ECM) components and increased matrix-metalloprotease (MMPs) activity are hallmarks of fibrosis. We developed an ELISA for quantification of MMP-9 derived collagen type III (CO3) degradation.......Accumulation of extracellular matrix (ECM) components and increased matrix-metalloprotease (MMPs) activity are hallmarks of fibrosis. We developed an ELISA for quantification of MMP-9 derived collagen type III (CO3) degradation....

Spontaneous and cytokine induced expression and activity of matrix metalloproteinases in human colonic epithelium

DEFF Research Database (Denmark)

Pedersen, G; Saermark, T; Kirkegaard, T

2009-01-01

levels in cells from inflamed IBD mucosa. MMP-2 and -8 mRNA were expressed inconsistently and MMP-11, -13 and -14 mRNA undetectable. Proteolytic MMP activity was detected in CEC supernatants and the level was increased significantly in inflamed IBD epithelium. The enzyme activity was inhibited strongly......Matrix metalloproteinases (MMPs) have been implicated in tissue damage associated with inflammatory bowel disease (IBD).As the role of the intestinal epithelium in this process is unknown, we determined MMP expression and enzyme activity in human colonic epithelial cells (CEC). MMP mRNA expression...... was assessed by reverse transcription-polymerase chain reaction in HT-29 and DLD-1 cells and in CEC isolated from biopsies from IBD and control patients. Total MMP activity in the cells was measured by a functional assay, based on degradation of a fluorescent synthetic peptide containing the specific bond...

Direct Integration of Dynamic Emissive Displays into Knitted Fabric Structures

Science.gov (United States)

Bellingham, Alyssa

Smart textiles are revolutionizing the textile industry by combining technology into fabric to give clothing new abilities including communication, transformation, and energy conduction. The advent of electroluminescent fibers, which emit light in response to an applied electric field, has opened the door for fabric-integrated emissive displays in textiles. This thesis focuses on the development of a flexible and scalable emissive fabric display with individually addressable pixels disposed within a fabric matrix. The pixels are formed in areas where a fiber supporting the dielectric and phosphor layers of an electroluminescent structure contacts a conductive surface. This conductive surface can be an external conductive fiber, yarn or wire, or a translucent conductive material layer deposited at set points along the electroluminescent fibers. Different contacting methods are introduced and the different ways the EL yarns can be incorporated into the knitted fabric are discussed. EL fibers were fabricated using a single yarn coating system with a custom, adjustable 3D printed slot die coater for even distribution of material onto the supporting fiber substrates. These fibers are mechanically characterized inside of and outside of a knitted fabric matrix to determine their potential for various applications, including wearables. A 4-pixel dynamic emissive display prototype is fabricated and characterized. This is the first demonstration of an all-knit emissive display with individually controllable pixels. The prototype is composed of a grid of fibers supporting the dielectric and phosphor layers of an electroluminescent (EL) device structure, called EL fibers, and conductive fibers acting as the top electrode. This grid is integrated into a biaxial weft knit structure where the EL fibers make up the rows and conductive fibers make up the columns of the reinforcement yarns inside the supporting weft knit. The pixels exist as individual segments of

Ultrasound-responsive gene-activated matrices for osteogenic gene therapy using matrix-assisted sonoporation.

Science.gov (United States)

Nomikou, N; Feichtinger, G A; Saha, S; Nuernberger, S; Heimel, P; Redl, H; McHale, A P

2018-01-01

Gene-activated matrix (GAM)-based therapeutics for tissue regeneration are limited by efficacy, the lack of spatiotemporal control and availability of target cells, all of which impact negatively on their translation to the clinic. Here, an advanced ultrasound-responsive GAM is described containing target cells that facilitates matrix-assisted sonoporation (MAS) to induce osteogenic differentiation. Ultrasound-responsive GAMs consisting of fibrin/collagen hybrid-matrices containing microbubbles, bone morphogenetic protein BMP2/7 coexpression plasmids together with C2C12 cells were treated with ultrasound either in vitro or following parenteral intramuscular implantation in vivo. Using direct measurement for alkaline phosphatase activity, von Kossa staining and immunohistochemical analysis for osteocalcin expression, MAS-stimulated osteogenic differentiation was confirmed in the GAMs in vitro 7 days after treatment with ultrasound. At day 30 post-treatment with ultrasound, ectopic osteogenic differentiation was confirmed in vivo using X-ray microcomputed tomography and histological analysis. Osteogenic differentiation was indicated by the presence of ectopic bone structures in all animals treated with MAS. In addition, bone volumes in this group were statistically greater than those in the control groups. This novel approach of incorporating a MAS capability into GAMs could be exploited to facilitate ex vivo gene transfer with subsequent surgical implantation or alternatively provide a minimally invasive means of stimulating in situ transgene delivery for osteoinductive gene-based therapies. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Simulation of sparse matrix array designs

Science.gov (United States)

Boehm, Rainer; Heckel, Thomas

2018-04-01

Matrix phased array probes are becoming more prominently used in industrial applications. The main drawbacks, using probes incorporating a very large number of transducer elements, are needed for an appropriate cabling and an ultrasonic device offering many parallel channels. Matrix arrays designed for extended functionality feature at least 64 or more elements. Typical arrangements are square matrices, e.g., 8 by 8 or 11 by 11 or rectangular matrixes, e.g., 8 by 16 or 10 by 12 to fit a 128-channel phased array system. In some phased array systems, the number of simultaneous active elements is limited to a certain number, e.g., 32 or 64. Those setups do not allow running the probe with all elements active, which may cause a significant change in the directivity pattern of the resulting sound beam. When only a subset of elements can be used during a single acquisition, different strategies may be applied to collect enough data for rebuilding the missing information from the echo signal. Omission of certain elements may be one approach, overlay of subsequent shots with different active areas may be another one. This paper presents the influence of a decreased number of active elements on the sound field and their distribution on the array. Solutions using subsets with different element activity patterns on matrix arrays and their advantages and disadvantages concerning the sound field are evaluated using semi-analytical simulation tools. Sound field criteria are discussed, which are significant for non-destructive testing results and for the system setup.

Sharp green electroluminescence from 1H-pyrazolo[3,4-b]quinoline-based light-emitting diodes

Science.gov (United States)

Tao, Y. T.; Balasubramaniam, E.; Danel, A.; Jarosz, B.; Tomasik, P.

2000-09-01

A multilayer organic light-emitting diode was fabricated using a fluorescent compound {6-N,N-diethylamino-1-methyl-3-phenyl-1H-pyrazolo[3,4-b]quinoline} (PAQ-NEt2) doped into the hole-transporting layer of NPB {4,4'-bis[N-(1-naphthyl-1-)-N-phenyl-amino]-biphenyl}, with the TPBI {2,2',2″-(1,3,5-phenylene)tris[1-phenyl-1H-benzimidazole]} as an electrontransporting material. At 16% PAQ-NEt2 doping concentration, the device gave a sharp, bright, and efficient green electroluminescence (EL) peaked at around 530 nm. The full width at half maximum of the EL is 60 nm, which is 60% of the green emission from typical NPB/AlQ [where AlQ=tris(8-hydroxyquinoline) aluminum] device. For the same concentration, a maximum luminance of 37 000 cd/m2 was obtained at 10.0 V and the maximum power, luminescence, and external quantum efficiencies were obtained 4.2 lm/W, 6.0 cd/A, and 1.6%, respectively, at 5.0 V.

Bright electroluminescence from a chelate phosphine oxide Eu{sup III} complex with high thermal performance

Energy Technology Data Exchange (ETDEWEB)

Xu Hui [School of Chemistry and Materials, Heilongjiang University, 74 Xuefu Road, Nangang District, Harbin 150080, Heilongjiang Province (China); Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 66 Xinmofan Road, Nanjing 21003, Jiangsu Province (China); Yin Kun; Wang Lianhui [Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 66 Xinmofan Road, Nanjing 21003, Jiangsu Province (China); Huang Wei [Institute of Advanced Materials (IAM), Fudan University, 220 Handan Road, Shanghai 200433 (China)], E-mail: wei-huang@njupt.edu.cn

2008-10-01

The chelate phosphine oxide ligand 1,8-bis(diphenylphosphino)naphthalene oxide (NaPO) was used to prepare complex 1 tris(2-thenoyltrifluoroacetonate)(1,8-bis(diphenylphosphino)naphthalene oxide)europium(III). The rigid structure of NaPO makes 1 have more compact structure resulting in a temperature of glass transition as high as 147 deg. C, which is the highest in luminescent Eu{sup III} complexes, and a higher decomposition temperature of 349 deg. C. The improvement of carrier transfer ability of NaPO was proved by Gaussian simulation. The multi-layered electroluminescent device based on 1 had a low turn-on voltage of 6.0 V, the maximum brightness of 601 cd m{sup -2} at 21.5 V and 481.4 mA cm{sup -2}, and the excellent voltage-independent spectral stability. These properties demonstrated NaPO cannot only be favorable to form the rigid and compact complex structure, and increase the thermal and morphological stability of the complex, but also reduce the formation of the exciplex.

How, with whom and when: an overview of CD147-mediated regulatory networks influencing matrix metalloproteinase activity

Science.gov (United States)

Grass, G. Daniel; Toole, Bryan P.

2015-01-01

Matrix metalloproteinases (MMPs) comprise a family of 23 zinc-dependent enzymes involved in various pathologic and physiologic processes. In cancer, MMPs contribute to processes from tumour initiation to establishment of distant metastases. Complex signalling and protein transport networks regulate MMP synthesis, cell surface presentation and release. Earlier attempts to disrupt MMP activity in patients have proven to be intolerable and with underwhelming clinical efficacy; thus targeting ancillary proteins that regulate MMP activity may be a useful therapeutic approach. Extracellular matrix metalloproteinase inducer (EMMPRIN) was originally characterized as a factor present on lung cancer cells, which stimulated collagenase (MMP-1) production in fibroblasts. Subsequent studies demonstrated that EMMPRIN was identical with several other protein factors, including basigin (Bsg), all of which are now commonly termed CD147. CD147 modulates the synthesis and activity of soluble and membrane-bound [membrane-type MMPs (MT-MMPs)] in various contexts via homophilic/heterophilic cell interactions, vesicular shedding or cell-autonomous processes. CD147 also participates in inflammation, nutrient and drug transporter activity, microbial pathology and developmental processes. Despite the hundreds of manuscripts demonstrating CD147-mediated MMP regulation, the molecular underpinnings governing this process have not been fully elucidated. The present review summarizes our present knowledge of the complex regulatory systems influencing CD147 biology and provides a framework to understand how CD147 may influence MMP activity. PMID:26604323

How, with whom and when: an overview of CD147-mediated regulatory networks influencing matrix metalloproteinase activity.

Science.gov (United States)

Grass, G Daniel; Toole, Bryan P

2015-11-24

Matrix metalloproteinases (MMPs) comprise a family of 23 zinc-dependent enzymes involved in various pathologic and physiologic processes. In cancer, MMPs contribute to processes from tumour initiation to establishment of distant metastases. Complex signalling and protein transport networks regulate MMP synthesis, cell surface presentation and release. Earlier attempts to disrupt MMP activity in patients have proven to be intolerable and with underwhelming clinical efficacy; thus targeting ancillary proteins that regulate MMP activity may be a useful therapeutic approach. Extracellular matrix metalloproteinase inducer (EMMPRIN) was originally characterized as a factor present on lung cancer cells, which stimulated collagenase (MMP-1) production in fibroblasts. Subsequent studies demonstrated that EMMPRIN was identical with several other protein factors, including basigin (Bsg), all of which are now commonly termed CD147. CD147 modulates the synthesis and activity of soluble and membrane-bound [membrane-type MMPs (MT-MMPs)] in various contexts via homophilic/heterophilic cell interactions, vesicular shedding or cell-autonomous processes. CD147 also participates in inflammation, nutrient and drug transporter activity, microbial pathology and developmental processes. Despite the hundreds of manuscripts demonstrating CD147-mediated MMP regulation, the molecular underpinnings governing this process have not been fully elucidated. The present review summarizes our present knowledge of the complex regulatory systems influencing CD147 biology and provides a framework to understand how CD147 may influence MMP activity. © 2016 Authors.

Modulation of the electroluminescence emission from ZnO/Si NCs/p-Si light-emitting devices via pulsed excitation

Science.gov (United States)

López-Vidrier, J.; Gutsch, S.; Blázquez, O.; Hiller, D.; Laube, J.; Kaur, R.; Hernández, S.; Garrido, B.; Zacharias, M.

2017-05-01

In this work, the electroluminescence (EL) emission of zinc oxide (ZnO)/Si nanocrystals (NCs)-based light-emitting devices was studied under pulsed electrical excitation. Both Si NCs and deep-level ZnO defects were found to contribute to the observed EL. Symmetric square voltage pulses (50-μs period) were found to notably enhance EL emission by about one order of magnitude. In addition, the control of the pulse parameters (accumulation and inversion times) was found to modify the emission lineshape, long inversion times (i.e., short accumulation times) suppressing ZnO defects contribution. The EL results were discussed in terms of the recombination dynamics taking place within the ZnO/Si NCs heterostructure, suggesting the excitation mechanism of the luminescent centers via a combination of electron impact, bipolar injection, and sequential carrier injection within their respective conduction regimes.

Effect of gold nanorods and nanocubes on electroluminescent performances in organic light-emitting diodes and its working mechanism

Directory of Open Access Journals (Sweden)

Ying Xu

2015-06-01

Full Text Available In this manuscript we investigated the influence of Au nanoparticles on electrical and electroluminescent (EL performances in organic light-emitting diodes (OLEDs via doping as-synthesized Au nanorods (NRs or nanocubes (NCs into hole transport layer (HTL. Through accurately controlling the distance between the Au NRs and the emitting layer, altering the guest emitter’s lifetime, and replacing Au NRs with Au NCs to satisfy a better spectrum overlap with the emission guest, we got a conclusion that doping Au NRs or NCs into HTL has no significant influence on the device’s electrical and EL performances, although we observed an increase in the spontaneous emission rate in a fluorescent material by the exciton-surface plasmon-coupling. Our results suggest that a further research on emission mechanism in surface plasmon-enhanced OLEDs is still in process.

Simvastatin Ameliorates Matrix Stiffness-Mediated Endothelial Monolayer Disruption.

Directory of Open Access Journals (Sweden)

Marsha C Lampi

Full Text Available Arterial stiffening accompanies both aging and atherosclerosis, and age-related stiffening of the arterial intima increases RhoA activity and cell contractility contributing to increased endothelium permeability. Notably, statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA reductase inhibitors whose pleiotropic effects include disrupting small GTPase activity; therefore, we hypothesized the statin simvastatin could be used to attenuate RhoA activity and inhibit the deleterious effects of increased age-related matrix stiffness on endothelial barrier function. Using polyacrylamide gels with stiffnesses of 2.5, 5, and 10 kPa to mimic the physiological stiffness of young and aged arteries, endothelial cells were grown to confluence and treated with simvastatin. Our data indicate that RhoA and phosphorylated myosin light chain activity increase with matrix stiffness but are attenuated when treated with the statin. Increases in cell contractility, cell-cell junction size, and indirect measurements of intercellular tension that increase with matrix stiffness, and are correlated with matrix stiffness-dependent increases in monolayer permeability, also decrease with statin treatment. Furthermore, we report that simvastatin increases activated Rac1 levels that contribute to endothelial barrier enhancing cytoskeletal reorganization. Simvastatin, which is prescribed clinically due to its ability to lower cholesterol, alters the endothelial cell response to increased matrix stiffness to restore endothelial monolayer barrier function, and therefore, presents a possible therapeutic intervention to prevent atherogenesis initiated by age-related arterial stiffening.

Synthesis, characterization and electroluminescence of two highly-twisted non-doped blue light-emitting materials

Science.gov (United States)

Gong, Xiaojie; Pan, Yipeng; Xie, Xiang; Tong, Tong; Chen, Runfeng; Gao, Deqing

2018-04-01

Two pyrene derivatives, substituted with 2-methylnaphthalene units on 1,3-position and 1,6-position of pyrene backbones, were designed and synthesized. DFT calculation confirmed that the two molecules were highly twisted and the dihedral angles between pyrene backbone and naphthalene unit were over 80°, being attributed to the steric hindrance of ortho-methyl group and the substitution position of pyrene itself. As a result, the intermolecular aggregation was greatly inhibited in the solid state, being beneficial for suppressing the fluorescence quenching. By analyzing the optical and thermal properties, it was found that the π-π conjugation extension could be adjusted and a balance for high fluorescent efficiency and avoiding quenching at the same time could be reached, which may guide the molecular design in the future. The electroluminescence properties of the non-doped devices were enhanced with the double hole-transporting layers by optimizing the energy level matching. The stable blue EL emission, with the Commission Internationaled'Eclairage (CIEx,y) color coordinates of (0.15, 0.13) and (0.15, 0.11) at 7, 8, 9 and 10 V respectively, was obtained.

Spray deposition of organic electroluminescent coatings for application in flexible light emitting devices

Directory of Open Access Journals (Sweden)

Mariya Aleksandrova

2015-12-01

Full Text Available Organic electroluminescent (EL films of tris(8-hydroxyquinolinatoaluminum (Alq3 mixed with polystyrene (PS binder were produced by spray deposition. The influence of the substrate temperature on the layer’s morphology and uniformity was investigated. The deposition conditions were optimized and simple flexible light-emitting devices consisting of indium-tin oxide/Alq3:PS/aluminum were fabricated on polyethylene terephthalate (PET foil to demonstrate the advantages of the sprayed organic coatings. Same structure was produced by thermal evaporation of Alq3 film as a reference. The influence of the deposition method on the film roughness and contact resistance at the electrode interfaces for both types of structures was estimated. The results were related to the devices’ efficiency. It was found that the samples with sprayed films turn on at 4 V, which is 2 V lower in comparison to the device with thermal evaporated Alq3. The current through the sprayed device is six times higher as well (17 mA vs. 2.8 mA at 6.5 V, which can be ascribed to the lower contact resistance at the EL film/electrode interfaces. This is due to the lower surface roughness of the pulverized layers.

Ultraviolet electroluminescence from n-ZnO/p-NiO heterojunction light-emitting diode

International Nuclear Information System (INIS)

Deng, R.; Yao, B.; Li, Y.F.; Xu, Y.; Li, J.C.; Li, B.H.; Zhang, Z.Z.; Zhang, L.G.; Zhao, H.F.; Shen, D.Z.

2013-01-01

The n-ZnO/p-NiO heterojunction was prepared by depositing a p-type NiO film on a c-plane sapphire by rf magnetron sputtering and then growing a n-type ZnO film on the NiO film by plasma-assisted molecular beam epitaxy. The heterojunction shows a diode-like rectification characteristic with a turn-on voltage of ∼3.6 V and emits UV light upon putting a forward bias. The intensity of the UV emission increases as injection current increases from 0.5 to 3.5 mA, but the wavelength of the UV emission decreases from 404 to 387 nm. It is demonstrated that the UV emission comes from near band-edge radiative recombination of electron and hole in the ZnO layer. The mechanism of the UV electroluminescence is discussed in the present work. - Highlights: ► The n-ZnO/p-NiO heterojunction was prepared by rf magnetron sputtering. ► The heterojunction shows a diode-like rectification characteristic with a turn-on voltage of ∼3.6 V. ► The heterojunction realizes UV EL emission with wavelength of 387 nm at the injection current of 3.5 mA.

Relative contribution of matrix metalloprotease and cysteine protease activities to cytokine-stimulated articular cartilage degradation

DEFF Research Database (Denmark)

Sondergaard, B C; Henriksen, K; Wulf, H

2006-01-01

OBJECTIVE: Both matrix metalloprotease (MMP) activity and cathepsin K (CK) activity have been implicated in cartilage turnover. We investigated the relative contribution of MMP activity and CK activity in cartilage degradation using ex vivo and in vivo models. METHODS: Bovine articular cartilage...... explants were stimulated with oncostatin M (OSM) 10 ng/ml and tumor necrosis factor-alpha (TNF-alpha) 20 ng/ml in the presence or absence of the broad-spectrum MMP inhibitor GM6001 and the cysteine protease inhibitor, E64. Cartilage degradation was evaluated in the conditioned medium by glycosaminoglycans...... was measured from CK-deficient mice. RESULTS: OSM and TNF-alpha combined induced significant (Pcartilage degradation products measured by hydroxyproline and CTX-II compared to vehicle control. The cytokines potently induced MMP expression, assessed by zymography, and CK expression...

Plasma membrane factor XIIIA transglutaminase activity regulates osteoblast matrix secretion and deposition by affecting microtubule dynamics.

Directory of Open Access Journals (Sweden)

Hadil F Al-Jallad

2011-01-01

Full Text Available Transglutaminase activity, arising potentially from transglutaminase 2 (TG2 and Factor XIIIA (FXIIIA, has been linked to osteoblast differentiation where it is required for type I collagen and fibronectin matrix deposition. In this study we have used an irreversible TG-inhibitor to 'block -and-track' enzyme(s targeted during osteoblast differentiation. We show that the irreversible TG-inhibitor is highly potent in inhibiting osteoblast differentiation and mineralization and reduces secretion of both fibronectin and type I collagen and their release from the cell surface. Tracking of the dansyl probe by Western blotting and immunofluorescence microscopy demonstrated that the inhibitor targets plasma membrane-associated FXIIIA. TG2 appears not to contribute to crosslinking activity on the osteoblast surface. Inhibition of FXIIIA with NC9 resulted in defective secretory vesicle delivery to the plasma membrane which was attributable to a disorganized microtubule network and decreased microtubule association with the plasma membrane. NC9 inhibition of FXIIIA resulted in destabilization of microtubules as assessed by cellular Glu-tubulin levels. Furthermore, NC9 blocked modification of Glu-tubulin into 150 kDa high-molecular weight Glu-tubulin form which was specifically localized to the plasma membrane. FXIIIA enzyme and its crosslinking activity were colocalized with plasma membrane-associated tubulin, and thus, it appears that FXIIIA crosslinking activity is directed towards stabilizing the interaction of microtubules with the plasma membrane. Our work provides the first mechanistic cues as to how transglutaminase activity could affect protein secretion and matrix deposition in osteoblasts and suggests a novel function for plasma membrane FXIIIA in microtubule dynamics.

Matrix completion by deep matrix factorization.

Science.gov (United States)

Fan, Jicong; Cheng, Jieyu

2018-02-01

Conventional methods of matrix completion are linear methods that are not effective in handling data of nonlinear structures. Recently a few researchers attempted to incorporate nonlinear techniques into matrix completion but there still exists considerable limitations. In this paper, a novel method called deep matrix factorization (DMF) is proposed for nonlinear matrix completion. Different from conventional matrix completion methods that are based on linear latent variable models, DMF is on the basis of a nonlinear latent variable model. DMF is formulated as a deep-structure neural network, in which the inputs are the low-dimensional unknown latent variables and the outputs are the partially observed variables. In DMF, the inputs and the parameters of the multilayer neural network are simultaneously optimized to minimize the reconstruction errors for the observed entries. Then the missing entries can be readily recovered by propagating the latent variables to the output layer. DMF is compared with state-of-the-art methods of linear and nonlinear matrix completion in the tasks of toy matrix completion, image inpainting and collaborative filtering. The experimental results verify that DMF is able to provide higher matrix completion accuracy than existing methods do and DMF is applicable to large matrices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Distribution and activity levels of matrix metalloproteinase 2 and 9 in canine and feline osteosarcoma

OpenAIRE

Gebhard, Christiane; Fuchs-Baumgartinger, Andrea; Razzazi-Fazeli, Ebrahim; Miller, Ingrid; Walter, Ingrid

2016-01-01

Overexpression of matrix metalloproteinases (MMPs) has been associated with increased tumor aggressiveness and metastasis dissemination. We investigated whether the contrasting metastatic behavior of feline and canine osteosarcoma is related to levels and activities of MMP2 and MMP9. Zymography and immunohistochemistry were used to determine expression levels of MMP2 and MMP9 in canine and feline osteosarcoma. Using immunohistochemistry, increased MMP9 levels were identified in most canine os...

Electroluminescence in quantum well heterostructures p-Al{sub x}Ga{sub 1-x}As/GaAs{sub 1-y}P{sub y}/n-Al{sub x}Ga{sub 1-x}As under uniaxial stress

Energy Technology Data Exchange (ETDEWEB)

Berman, Irina V. [Physics Department, San Jose State University, CA (United States); Bogdanov, Evgeniy V.; Minina, Natalia Ya.; Shirokov, Stanislav S.; Yunovich, Alexander E. [Physics Department, Lomonosov Moscow State University (Russian Federation); Kissel, Heiko [R and D Department, DILAS Diodenlaser GmbH, (Germany)

2009-03-15

We present new results on the influence of uniaxial stress up to P=4 kbar on the electroluminescence spectra and current-voltage characteristics of p-Al{sub x}Ga{sub 1-x}As/GaAs{sub 1-y}P{sub y}/n-Al{sub x}Ga{sub 1-x}As double heterostructures usually used in TM emitting 808 nm high-power diode lasers. With increasing stress, the emission spectra demonstrate a blue shift of up to 25 meV at a pressure of P=4 kbar, while the electroluminescence intensity increases under compression. The different behavior of the current-voltage characteristics under uniaxial stress along[110] and[1 anti 10] directions is mainly determined by the arising piezoelectric field. The results are also discussed in terms of changes in the band structure under uniaxial compression. The construction of the cryostat for optical measurements under uniaxial stress at liquid nitrogen temperature is described in the paper. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Control of a White Organic Light Emitting Diode emission parameters using a single doped RGB active layer

Energy Technology Data Exchange (ETDEWEB)

Pereira, D. [Departamento de Ciência dos Materiais e i3N – Instituto de Nanoestruturas, Nanomodelação e Nanofabricação, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica (Portugal); Pinto, A.; Califórnia, A.; Gomes, J. [CeNTI – Centro de Nanotecnologia, Materiais Técnicos, Funcionais e Inteligentes, Rua Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão (Portugal); Pereira, L., E-mail: luiz@ua.pt [Departmento de Física e i3N – Instituto de Nanoestruturas, Nanomodelação e Nanofabricação, Universidade de Aveiro, 3810-193 Aveiro (Portugal)

2016-09-15

Highlights: • A simple WOLED for Solid State Lighting is proposed with high color stability. • Energy transfer and electroluminescence dynamics of a single RGB layer for WOLEDs. • White shade modulation and stability over large emitting areas and applied voltages. - Abstract: Solid State Lighting technologies based on Organic Light Emitting Diodes, became an interesting focus due to their unique properties. The use of a unique RGB active layer for white emission, although simple in theory, shows difficulty to stabilize both CIE coordinates and color modulation. In this work, a WOLED using a simple RGB layer, was developed achieving a high color stability and shade modulation. The RGB matrix comprises a blue host material NPB, doped with two guests, a green (Coumarin 153) and a red (DCM1) in low concentrations. The RGB layer carrier dynamics allows for the white emission in low device complexity and high stability. This was also shown independent of the white shade, obtained through small changes in the red dopant resulting in devices ranging from warm to cool white i.e. an easy color tuning. A detailed analysis of the opto-electrical behavior is made.

Control of a White Organic Light Emitting Diode emission parameters using a single doped RGB active layer

International Nuclear Information System (INIS)

Pereira, D.; Pinto, A.; Califórnia, A.; Gomes, J.; Pereira, L.

2016-01-01

Highlights: • A simple WOLED for Solid State Lighting is proposed with high color stability. • Energy transfer and electroluminescence dynamics of a single RGB layer for WOLEDs. • White shade modulation and stability over large emitting areas and applied voltages. - Abstract: Solid State Lighting technologies based on Organic Light Emitting Diodes, became an interesting focus due to their unique properties. The use of a unique RGB active layer for white emission, although simple in theory, shows difficulty to stabilize both CIE coordinates and color modulation. In this work, a WOLED using a simple RGB layer, was developed achieving a high color stability and shade modulation. The RGB matrix comprises a blue host material NPB, doped with two guests, a green (Coumarin 153) and a red (DCM1) in low concentrations. The RGB layer carrier dynamics allows for the white emission in low device complexity and high stability. This was also shown independent of the white shade, obtained through small changes in the red dopant resulting in devices ranging from warm to cool white i.e. an easy color tuning. A detailed analysis of the opto-electrical behavior is made.

Combat vehicle crew helmet-mounted display: next generation high-resolution head-mounted display

Science.gov (United States)

Nelson, Scott A.

1994-06-01

The Combat Vehicle Crew Head-Mounted Display (CVC HMD) program is an ARPA-funded, US Army Natick Research, Development, and Engineering Center monitored effort to develop a high resolution, flat panel HMD for the M1 A2 Abrams main battle tank. CVC HMD is part of the ARPA High Definition Systems (HDS) thrust to develop and integrate small (24 micrometers square pels), high resolution (1280 X 1024 X 6-bit grey scale at 60 frame/sec) active matrix electroluminescent (AMEL) and active matrix liquid crystal displays (AMLCD) for head mounted and projection applications. The Honeywell designed CVC HMD is a next generation head-mounted display system that includes advanced flat panel image sources, advanced digital display driver electronics, high speed (> 1 Gbps) digital interconnect electronics, and light weight, high performance optical and mechanical designs. The resulting dramatic improvements in size, weight, power, and cost have already led to program spin offs for both military and commercial applications.

Characterization of silica particles prepared via urease-catalyzed urea hydrolysis and activity of urease in sol–gel silica matrix

International Nuclear Information System (INIS)

Kato, Katsuya; Nishida, Masakazu; Ito, Kimiyasu; Tomita, Masahiro

2012-01-01

Highlights: ► Silica precipitation occurred via urease-catalytic reactions. ► Higher urease activity for silica synthesis enables mesostructure of silica–urease composites. ► Urease encapsulating in silica matrix retained high activity. - Abstract: Urease templated precipitation of silica synthesized by sol–gel chemistry produces a composite material allowing high urease activity. This study investigates the structural properties of the composite material that allow for the retention of the urease hydrolysis activity. Scanning (SEM) and transmission (TEM) electron microscopy reveal that the composite has a mesoporous structure composed of closely packed spherical structures ∼20–50 nm in diameter. Brunauer–Emmett–Teller (BET) analysis revealed that the surface area and pore volume of the composite prepared under the conditions of 50 mM urea and 25 °C is relatively high (324 m 2 /g and 1.0 cm 3 /g). These values are equivalent to those of usual mesoporous silica materials synthesized from the self-assembly of triblock copolymers as organic templates. In addition, after encapsulating in a sol–gel silica matrix, urease retained high activity (∼90% of the activity compared with native urease). Our results suggest a new method for synthesizing mesoporous silica materials with highly tunable pore sizes and shapes under mild conditions.

Effect of the glass transition temperature on alpha-amylase activity in a starch matrix.

Science.gov (United States)

Chaudhary, Vinita; Panyoyai, Naksit; Small, Darryl M; Shanks, Robert A; Kasapis, Stefan

2017-02-10

This study optimises a protocol for the estimation of α-amylase activity in a condensed starch matrix in the vicinity of the glass transition region. Enzymatic activity on the vitrified starch system was compared with that of a reference substrate, maltodextrin. The activity was assayed as the rate of release of reducing sugar using a dinitrosalicylic acid procedure. The condensed carbohydrate matrices served the dual purpose of acting as a substrate as well as producing a pronounced effect on the ability to enzymatic hydrolysis. Activation energies were estimated throughout the glass transition region of condensed carbohydrate preparations based on the concept of the spectroscopic shift factor. Results were used to demonstrate a considerable moderation by the mechanical glass transition temperature, beyond the expected linear effect of the temperature dependence, on the reaction rate of starch hydrolysis by α-amylase in comparison with the low-molecular weight chain of maltodextrin. Copyright © 2016. Published by Elsevier Ltd.

Analytical Model of Water Flow in Coal with Active Matrix

Science.gov (United States)

Siemek, Jakub; Stopa, Jerzy

2014-12-01

This paper presents new analytical model of gas-water flow in coal seams in one dimension with emphasis on interactions between water flowing in cleats and coal matrix. Coal as a flowing system, can be viewed as a solid organic material consisting of two flow subsystems: a microporous matrix and a system of interconnected macropores and fractures. Most of gas is accumulated in the microporous matrix, where the primary flow mechanism is diffusion. Fractures and cleats existing in coal play an important role as a transportation system for macro scale flow of water and gas governed by Darcy's law. The coal matrix can imbibe water under capillary forces leading to exchange of mass between fractures and coal matrix. In this paper new partial differential equation for water saturation in fractures has been formulated, respecting mass exchange between coal matrix and fractures. Exact analytical solution has been obtained using the method of characteristics. The final solution has very simple form that may be useful for practical engineering calculations. It was observed that the rate of exchange of mass between the fractures and the coal matrix is governed by an expression which is analogous to the Newton cooling law known from theory of heat exchange, but in present case the mass transfer coefficient depends not only on coal and fluid properties but also on time and position. The constant term of mass transfer coefficient depends on relation between micro porosity and macro porosity of coal, capillary forces, and microporous structure of coal matrix. This term can be expressed theoretically or obtained experimentally. W artykule zaprezentowano nowy model matematyczny przepływu wody i gazu w jednowymiarowej warstwie węglowej z uwzględnieniem wymiany masy między systemem szczelin i matrycą węglową. Węgiel jako system przepływowy traktowany jest jako układ o podwójnej porowatości i przepuszczalności, składający się z mikroporowatej matrycy węglowej oraz z

Matrix and Tensor Completion on a Human Activity Recognition Framework.

Science.gov (United States)

Savvaki, Sofia; Tsagkatakis, Grigorios; Panousopoulou, Athanasia; Tsakalides, Panagiotis

2017-11-01

Sensor-based activity recognition is encountered in innumerable applications of the arena of pervasive healthcare and plays a crucial role in biomedical research. Nonetheless, the frequent situation of unobserved measurements impairs the ability of machine learning algorithms to efficiently extract context from raw streams of data. In this paper, we study the problem of accurate estimation of missing multimodal inertial data and we propose a classification framework that considers the reconstruction of subsampled data during the test phase. We introduce the concept of forming the available data streams into low-rank two-dimensional (2-D) and 3-D Hankel structures, and we exploit data redundancies using sophisticated imputation techniques, namely matrix and tensor completion. Moreover, we examine the impact of reconstruction on the classification performance by experimenting with several state-of-the-art classifiers. The system is evaluated with respect to different data structuring scenarios, the volume of data available for reconstruction, and various levels of missing values per device. Finally, the tradeoff between subsampling accuracy and energy conservation in wearable platforms is examined. Our analysis relies on two public datasets containing inertial data, which extend to numerous activities, multiple sensing parameters, and body locations. The results highlight that robust classification accuracy can be achieved through recovery, even for extremely subsampled data streams.

Multifaceted role of matrix metalloproteinases (MMPs)

OpenAIRE

Singh, Divya; Srivastava, Sanjeev K.; Chaudhuri, Tapas K.; Upadhyay, Ghanshyam

2015-01-01

Matrix metalloproteinases (MMPs), a large family of calcium-dependent zinc-containing endopeptidases, are involved in the tissue remodeling and degradation of the extracellular matrix. MMPs are widely distributed in the brain and regulate various processes including microglial activation, inflammation, dopaminergic apoptosis, blood-brain barrier disruption, and modulation of ?-synuclein pathology. High expression of MMPs is well documented in various neurological disorders including Parkinson...

Understanding effects of matrix protease and matrix organization on directional persistence and translational speed in three-dimensional cell migration.

Science.gov (United States)

Zaman, Muhammad H; Matsudaira, Paul; Lauffenburger, Douglas A

2007-01-01

Recent studies have shown significant differences in migration mechanisms between two- and three-dimensional environments. While experiments have suggested a strong dependence of in vivo migration on both structure and proteolytic activity, the underlying biophysics of such dependence has not been studied adequately. In addition, the existing models of persistent random walk migration are primarily based on two-dimensional movement and do not account for the effect of proteolysis or matrix inhomogeneity. Using lattice Monte Carlo methods, we present a model to study the role of matrix metallo-proteases (MMPs) on directional persistence and speed. The simulations account for a given cell's ability to deform as well as to digest the matrix as the cell moves in three dimensions. Our results show a bimodal dependence of speed and persistence on matrix pore size and suggest high sensitivity on MMP activity, which is in very good agreement with experimental studies carried out in 3D matrices.

MMP-9 directed shRNAs as relevant inhibitors of matrix metalloproteinase 9 activity and signaling

Directory of Open Access Journals (Sweden)

Ewa Nowak

2013-08-01

Full Text Available Introduction: The main function of matrix metalloproteinases is the degradation of extracellular matrix components, which is related to changes in the proliferation of cells, their differentiation, motility, and death. MMPs play an important role in physiological processes such as embryogenesis, angiogenesis and tissue remodeling. The increase of MMPs activity is also observed in pathological conditions including tumorigenesis where MMP-2 (gelatinase A and MMP-9 (gelatinase B show the ability to degrade the basement membrane of vessels and they are involved in metastasis. The aim of our study was to verify the changes of MMP-9 enzymatic activity and the mobility of cells after inhibition of MMP-9 gene expression.Material and Methods: The oligonucleotide shRNA insert had been designed to silence MMP-9 gene expression and was cloned into the pSUPER.neo expression vector. The construct was introduced into the HeLa (CCL-2 cervical cancer cells by lipotransfection. Simultaneously in control cells MMP-9 were inhibited by doxycycline. Changes in activity of MMP-9 were analyzed by gelatin zymography and wound-healing assay.Results/Conclusions: Gelatin zymography allowed us to confirm that activity of MMP-9 in cells transfected by shRNA-MMP-9 and treated by doxycycline were similar and significantly lower in comparison with control cells. Phenotypic tests of migration in vitro confirm statistically significant (P<0.05 changes in cell migration – control cells healed 3 to 5 times faster in comparison with transfected or doxycycline treated cells. Our studies show the significant role of MMP-9 in mobility and invasiveness of tumor cells, thus indicating a potential target point of interest for gene therapy.

Color tunable electroluminescence and resistance switching from a ZnO-nanorod–TaO_x–p-GaN heterojunction

International Nuclear Information System (INIS)

Zhao, J L; Teo, K L; Zheng, K; Sun, X W

2016-01-01

Well-aligned ZnO nanorods have been prepared on p-GaN–sapphire using a vapor phase transport (VPT) technique. A thin sputtered layer of TaO_x is employed as the intermediate layer and an n-ZnO–TaO_x–p-GaN heterojunction device has been achieved. The current transport of the heterojunction exhibited a typical resistance switching behavior, which originated from the filament forming and breaking in the TaO_x layer. Color controllable electroluminescence (EL) was observed from the biased heterojunction at room temperature. Bluish-white wide band emission is achieved from the forward biased device in both the high resistance and low resistance states, while red emission can only be observed for the reverse biased device in the low resistance state. The correlation between the EL and resistance switching has been analyzed in-depth based on the interface band diagram of the heterojunction. (paper)

Blueshift of electroluminescence from single n-InP nanowire/p-Si heterojunctions due to the Burstein-Moss effect

International Nuclear Information System (INIS)

Liu, C; Dai, L; You, L P; Xu, W J; Qin, G G

2008-01-01

Single-crystalline n-type InP nanowires (NWs) with different electron concentrations were synthesized on Si substrates via the vapor phase transport method. The electrical properties of the InP nanowires were investigated by fabricating and measuring single NW field-effect transistors (FETs). Single InP NW/p + -Si heterojunctions were fabricated, and electroluminescence (EL) spectra from them were studied. It was found that both the photoluminescence (PL) spectra of the InP NWs and the EL spectra of the heterojunctions blueshift from 920 to 775 nm when the electron concentrations of the InP NWs increase from 2 x 10 17 to 1.4 x 10 19 cm -3 . The blueshifts can be attributed to the Burstein-Moss effect rather than the quantum confinement effect in the InP NWs. The large blueshifts observed in this study indicate a potential application of InP NWs in nano-multicolour displays.

Synthesis, structures, and electroluminescent properties of scandium N,O-chelated complexes toward near-white organic light-emitting diodes.

Science.gov (United States)

Katkova, Marina A; Balashova, Tatyana V; Ilichev, Vasilii A; Konev, Alexey N; Isachenkov, Nikolai A; Fukin, Georgy K; Ketkov, Sergey Yu; Bochkarev, Mikhail N

2010-06-07

Three members of a new class of electroluminescent, neutral, and monomeric scandium N,O-chelate complexes, namely, Sc(III)-tris-2-(2-benzoimidazol-2-yl)phenolate (1), Sc(III)-tris-2-(2-benzoxyazol-2-yl)phenolate (2), and Sc(III)-tris-2-(2-benzothiazol-2-yl)phenolate (3), have been prepared and X-ray characterized. DFT calculations have been performed. In contrast to the most frequently applied dual or multiple dopants in multilayer white OLED devices, all our simpler devices with the configuration of indium tin oxide/N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine/neat scandium complex/Yb exhibit close to near-white emission with a blue hue (CIE(x,y) = 0.2147, 0.2379) in the case of 1, a cyan hue (0.2702, 0.3524) in the case of 2, and a yellowish hue (0.3468; 0.4284) in the case of 3.

Distribution and activity levels of matrix metalloproteinase 2 and 9 in canine and feline osteosarcoma.

Science.gov (United States)

Gebhard, Christiane; Fuchs-Baumgartinger, Andrea; Razzazi-Fazeli, Ebrahim; Miller, Ingrid; Walter, Ingrid

2016-01-01

Overexpression of matrix metalloproteinases (MMPs) has been associated with increased tumor aggressiveness and metastasis dissemination. We investigated whether the contrasting metastatic behavior of feline and canine osteosarcoma is related to levels and activities of MMP2 and MMP9. Zymography and immunohistochemistry were used to determine expression levels of MMP2 and MMP9 in canine and feline osteosarcoma. Using immunohistochemistry, increased MMP9 levels were identified in most canine osteosarcomas, whereas cat samples more often displayed moderate levels. High levels of pro-MMP9, pro-MMP2, and active MMP2 were detected by gelatin zymography in both species, with significantly higher values for active MMP2 in canine osteosarcoma. These findings indicate that MMP2 is probably involved in canine and feline osteosarcoma and their expression and activity could be associated with the different metastatic behavior of canine and feline osteosarcoma.

Acrolein activates matrix metalloproteinases by increasing reactive oxygen species in macrophages

International Nuclear Information System (INIS)

O'Toole, Timothy E.; Zheng Yuting; Hellmann, Jason; Conklin, Daniel J.; Barski, Oleg; Bhatnagar, Aruni

2009-01-01

Acrolein is a ubiquitous component of environmental pollutants such as automobile exhaust, cigarette, wood, and coal smoke. It is also a natural constituent of several foods and is generated endogenously during inflammation or oxidation of unsaturated lipids. Because increased inflammation and episodic exposure to acrolein-rich pollutants such as traffic emissions or cigarette smoke have been linked to acute myocardial infarction, we examined the effects of acrolein on matrix metalloproteinases (MMPs), which destabilize atherosclerotic plaques. Our studies show that exposure to acrolein resulted in the secretion of MMP-9 from differentiated THP-1 macrophages. Acrolein-treatment of macrophages also led to an increase in reactive oxygen species (ROS), free intracellular calcium ([Ca 2+ ] i ), and xanthine oxidase (XO) activity. ROS production was prevented by allopurinol, but not by rotenone or apocynin and by buffering changes in [Ca 2+ ] I with BAPTA-AM. The increase in MMP production was abolished by pre-treatment with the antioxidants Tiron and N-acetyl cysteine (NAC) or with the xanthine oxidase inhibitors allopurinol or oxypurinol. Finally, MMP activity was significantly stimulated in aortic sections from apoE-null mice containing advanced atherosclerotic lesions after exposure to acrolein ex vivo. These observations suggest that acrolein exposure results in MMP secretion from macrophages via a mechanism that involves an increase in [Ca 2+ ] I , leading to xanthine oxidase activation and an increase in ROS production. ROS-dependent activation of MMPs by acrolein could destabilize atherosclerotic lesions during brief episodes of inflammation or pollutant exposure.

Acrolein activates matrix metalloproteinases by increasing reactive oxygen species in macrophages.

Science.gov (United States)

O'Toole, Timothy E; Zheng, Yu-Ting; Hellmann, Jason; Conklin, Daniel J; Barski, Oleg; Bhatnagar, Aruni

2009-04-15

Acrolein is a ubiquitous component of environmental pollutants such as automobile exhaust, cigarette, wood, and coal smoke. It is also a natural constituent of several foods and is generated endogenously during inflammation or oxidation of unsaturated lipids. Because increased inflammation and episodic exposure to acrolein-rich pollutants such as traffic emissions or cigarette smoke have been linked to acute myocardial infarction, we examined the effects of acrolein on matrix metalloproteinases (MMPs), which destabilize atherosclerotic plaques. Our studies show that exposure to acrolein resulted in the secretion of MMP-9 from differentiated THP-1 macrophages. Acrolein-treatment of macrophages also led to an increase in reactive oxygen species (ROS), free intracellular calcium ([Ca2+](i)), and xanthine oxidase (XO) activity. ROS production was prevented by allopurinol, but not by rotenone or apocynin and by buffering changes in [Ca2+](I) with BAPTA-AM. The increase in MMP production was abolished by pre-treatment with the antioxidants Tiron and N-acetyl cysteine (NAC) or with the xanthine oxidase inhibitors allopurinol or oxypurinol. Finally, MMP activity was significantly stimulated in aortic sections from apoE-null mice containing advanced atherosclerotic lesions after exposure to acrolein ex vivo. These observations suggest that acrolein exposure results in MMP secretion from macrophages via a mechanism that involves an increase in [Ca2+](I), leading to xanthine oxidase activation and an increase in ROS production. ROS-dependent activation of MMPs by acrolein could destabilize atherosclerotic lesions during brief episodes of inflammation or pollutant exposure.

CMOS dot matrix microdisplay

Science.gov (United States)

Venter, Petrus J.; Bogalecki, Alfons W.; du Plessis, Monuko; Goosen, Marius E.; Nell, Ilse J.; Rademeyer, P.

2011-03-01

Display technologies always seem to find a wide range of interesting applications. As devices develop towards miniaturization, niche applications for small displays may emerge. While OLEDs and LCDs dominate the market for small displays, they have some shortcomings as relatively expensive technologies. Although CMOS is certainly not the dominating semiconductor for photonics, its widespread use, favourable cost and robustness present an attractive potential if it could find application in the microdisplay environment. Advances in improving the quantum efficiency of avalanche electroluminescence and the favourable spectral characteristics of light generated through the said mechanism may afford CMOS the possibility to be used as a display technology. This work shows that it is possible to integrate a fully functional display in a completely standard CMOS technology mainly geared towards digital design while using light sources completely compatible with the process and without any post processing required.

Histone Deacetylase 3 Suppresses Erk Phosphorylation and Matrix Metalloproteinase (Mmp)-13 Activity in Chondrocytes

Science.gov (United States)

Carpio, Lomeli R.; Bradley, Elizabeth W.; Westendorf, Jennifer J.

2017-01-01

Histone deacetylase inhibitors are emerging therapies for many diseases including cancers and neurological disorders; however, these drugs are teratogens to the developing skeleton. Hdac3 is essential for proper endochondral ossification as its deletion in chondrocytes increases cytokine signaling and the expression of matrix remodeling enzymes. Here we explored the mechanism by which Hdac3 controls Mmp13 expression in chondrocytes. In Hdac3-depleted chondrocytes, Erk1/2 as well as its downstream substrate, Runx2, were hyperphosphorylated as a result of decreased expression and activity of the Erk1/2 specific phosphatase, Dusp6. Erk1/2 kinase inhibitors and Dusp6 adenoviruses reduced Mmp13 expression and partially rescued matrix production in Hdac3-deficient chondrocytes. Postnatal chondrocyte-specific deletion of Hdac3 with an inducible Col2a1-Cre caused premature production of pErk1/2 and Mmp13 in the growth plate. Thus, Hdac3 controls the temporal and spatial expression of tissue-remodeling genes in chondrocytes to ensure proper endochondral ossification during development. PMID:27662443

Activation of matrix metalloproteinases following anti-Aβ immunotherapy; implications for microhemorrhage occurrence

Directory of Open Access Journals (Sweden)

Ridnour Lisa A

2011-09-01

Full Text Available Abstract Background Anti-Aβ immunotherapy is a promising approach to the prevention and treatment of Alzheimer's disease (AD currently in clinical trials. There is extensive evidence, both in mice and humans that a significant adverse event is the occurrence of microhemorrhages. Also, vasogenic edema was reported in phase 2 of a passive immunization clinical trial. In order to overcome these vascular adverse effects it is critical that we understand the mechanism(s by which they occur. Methods We have examined the matrix metalloproteinase (MMP protein degradation system in two previously published anti-Aβ immunotherapy studies. The first was a passive immunization study in which we examined 22 month old APPSw mice that had received anti-Aβ antibodies for 1, 2 or 3 months. The second is an active vaccination study in which we examined 16 month old APPSw/NOS2-/- mice treated with Aβ vaccination for 4 months. Results There is a significant activation of the MMP2 and MMP9 proteinase degradation systems by anti-Aβ immunotherapy, regardless of whether this is delivered through active vaccination or passive immunization. We have characterized this activation by gene expression, protein expression and zymography assessment of MMP activity. Conclusions Since the MMP2 and MMP9 systems are heavily implicated in the pathophysiology of intracerbral hemorrhage, these data may provide a potential mechanism of microhemorrhage due to immunotherapy. Increased activity of the MMP system, therefore, is likely to be a major factor in increased microhemorrhage occurrence.

A marketing matrix for health care organizations.

Science.gov (United States)

Weaver, F J; Gombeski, W R; Fay, G W; Eversman, J J; Cowan-Gascoigne, C

1986-06-01

Irrespective of the formal marketing structure successful marketing for health care organizations requires the input on many people. Detailed here is the Marketing Matrix used at the Cleveland Clinic Foundation in Cleveland, Ohio. This Matrix is both a philosophy and a tool for clarifying and focusing the organization's marketing activities.

Correlation of expression and activity of matrix metalloproteinase-9 and -2 in human gingival cells of periodontitis patients.

Science.gov (United States)

Kim, Kyung-A; Chung, Soo-Bong; Hawng, Eun-Young; Noh, Seung-Hyun; Song, Kwon-Ho; Kim, Hanna-Hyun; Kim, Cheorl-Ho; Park, Young-Guk

2013-02-01

Matrix metalloproteinases (MMPs) are capable of degrading extracellular matrix, and they are inducible enzymes depending on an inflammatory environment such as periodontitis and bacterial infection in periodontal tissue. Gingival inflammation has been postulated to be correlated with the production of MMP-2 and MMP-9. The objective of this study was to quantify the expression and activity of MMP-9 and -2, and to determine the correlation between activity and expression of these MMPs in human gingival tissues with periodontitis. The gingival tissues of 13 patients were homogenized in 500 µL of phosphate buffered saline with a protease inhibitor cocktail. The expression and activity of MMP-2 and -9 were measured by enzyme-linked immunosorbent assay and Western blot analysis, and quantified by a densitometer. For the correlation line, statistical analysis was performed using the Systat software package. MMP-9 was highly expressed in all gingival tissue samples, whereas MMP-2 was underexpressed compared with MMP-9. MMP-9 activity increased together with the MMP-9 expression level, with a positive correlation (r=0.793, P=0.01). The correlation was not observed in MMP-2. The expression of MMP-2 and -9 might contribute to periodontal physiological and pathological processes, and the degree of MMP-9 expression and activity are predictive indicators relevant to the progression of periodontitis.

Design and development of low-power driven hybrid electroluminescent lamp from carbon nanotube embedded phosphor material

International Nuclear Information System (INIS)

Yadav, Deepika; Mishra, Savvi; Shanker, Virendra; Haranath, D.

2013-01-01

Highlights: •We are first to report CNT embedded ZnS:Mn hybrid EL system. •Achieved efficient orange-red EL emission at low operating voltages ( AC ). •Facile technique to induce conductive paths inside the ZnS particle to trigger EL. •Detailed electrical characterization of EL lamp is presented. -- Abstract: We present a novel methodology to design a hybrid electroluminescent (EL) lamp by embedding carbon nanotubes (CNTs) inside the ZnS:Mn phosphor particles by conventional solid state diffusion technique. By doing so, the phosphor particles exhibited increase in EL brightness and efficiency at low operating voltages ( AC ). Interestingly, shorter the length of CNTs used, greater was the field enhancement effect and lower was the operating voltages to glow the EL lamps. The role of CNTs have been identified to form conductive paths inside the ZnS particle thereby triggering EL due to electron injection to luminescent centers (Mn 2+ ) at nominal voltages. In addition, a detailed electrical characterization of the novel EL lamp along with its spectral energy distribution studies are presented

Interfacial exciplex electroluminescence between diamine derivatives with starburst molecular structure and tris(acetylacetonato)-(mono-phenothroline) thulium

International Nuclear Information System (INIS)

He Hong; Li Wenlian; Su Zisheng; Chu Bei; Bi Defeng; Chen Yiren; Wang Dan; Su Wenming; Li Bin

2009-01-01

The authors demonstrate the interfacial exciplex electroluminescence (EL) between tris(acetylacetonato)-(mono-phenothroline) thulium [Tm(AcA) 3 phen] and two diamine derivatives with starburst molecular structure- 4,4',4''-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA) and 4,4',4''-tris[3-methyl-pheny(phenyl)-amino]triphenyl-amine (m-MTDATA), both of which have the same ionization potential (IP) (approximately 5.1 eV). When the Tm-complex and the two diamine derivatives are respectively used as the electron accepter and donors, the two EL devices exhibit different exciplex emissions, which verifies our previously reported opinion regarding the effect of the different substitutes on exciplex emission [W.M. Su, W.L. Li, Q. Xin, Z.S. Su, B. Chu, D.F. Bi, H. He, J.H. Niu, Appl. Phys. Lett. 91 (2007) 043508]. When the mixture of the two diamine derivatives is used as a donor, a white EL device with the Commission International de l'Eclairage (CIE) coordinates of (0.277, 0.323) is achieved. The exciplex formation mechanisms of the devices with the two different donors are discussed

Electroluminescence of organic light-emitting diodes consisting of an undoped (pbi)2Ir(acac) phosphorescent layer

Science.gov (United States)

Lei, Xia; Yu, Junsheng; Zhao, Juan; Jiang, Yadong

2011-11-01

The electroluminescence (EL) characteristics of phosphorescent organic light-emitting diodes (OLEDs) with an undoped bis(1,2-dipheny1-1H-benzoimidazole) iridium (acetylacetonate) [(pbi)2Ir(acac)] emissive layer (EML) of various film thicknesses were studied. The results showed that the intensity of green light emission decreased rapidly with the increasing thickness of (pbi)2Ir(acac), which was relevant to the triplet excimer emission. It suggested that the concentration quenching of monomer emission in the undoped (pbi)2Ir(acac) film was mainly due to the formation of triplet excimer and partly due to the triplet-triplet annihilation (TTA) and triplet-polaron annihilation (TPA). A green OLED with a maximum luminance of 26,531 cd/m2, a current efficiency of 36.2 cd/A, and a power efficiency of 32.4 lm/W was obtained, when the triplet excimer emission was eliminated. Moreover, the white OLED with low efficiency roll-off was realized due to the broadened recombination zone and reduced quenching effects in the EML when no electron blocking layer was employed.

Chromium liquid waste inertization in an inorganic alkali activated matrix: Leaching and NMR multinuclear approach

International Nuclear Information System (INIS)

Ponzoni, Chiara; Lancellotti, Isabella; Barbieri, Luisa; Spinella, Alberto; Saladino, Maria Luisa; Martino, Delia Chillura; Caponetti, Eugenio; Armetta, Francesco; Leonelli, Cristina

2015-01-01

Highlights: • Inertization of chromium liquid waste in aluminosilicate matrix. • Water less inertization technique exploiting the waste water content. • Liquid waste inertization without drying step. • Long term stabilization study through leaching test. • SEM analysis and 29 Si and 27 Al MAS NMR in relation with long curing time. - Abstract: A class of inorganic binders, also known as geopolymers, can be obtained by alkali activation of aluminosilicate powders at room temperature. The process is affected by many parameters (curing time, curing temperature, relative humidity etc.) and leads to a resistant matrix usable for inertization of hazardous waste. In this study an industrial liquid waste containing a high amount of chromium (≈2.3 wt%) in the form of metalorganic salts is inertized into a metakaolin based geopolymer matrix. One of the innovative aspects is the exploitation of the water contained in the waste for the geopolymerization process. This avoided any drying treatment, a common step in the management of liquid hazardous waste. The evolution of the process - from the precursor dissolution to the final geopolymer matrix hardening - of different geopolymers containing a waste amount ranging from 3 to 20% wt and their capability to inertize chromium cations were studied by: i) the leaching tests, according to the EN 12,457 regulation, at different curing times (15, 28, 90 and 540 days) monitoring releases of chromium ions (Cr(III) and Cr(VI)) and the cations constituting the aluminosilicate matrix (Na, Si, Al); ii) the humidity variation for different curing times (15 and 540 days); iii) SEM characterization at different curing times (28 and 540 days); iv) the trend of the solution conductivity and pH during the leaching test; v) the characterization of the short-range ordering in terms of T−O−T bonds (where T is Al or Si) by 29 Si and 27 Al solid state magic-angle spinning nuclear magnetic resonance (ss MAS NMR) for geopolymers

Chromium liquid waste inertization in an inorganic alkali activated matrix: Leaching and NMR multinuclear approach

Energy Technology Data Exchange (ETDEWEB)

Ponzoni, Chiara, E-mail: chiara.ponzoni@unimore.it [University of Modena and Reggio Emilia, Department of Engineering “Enzo Ferrari”, Modena (Italy); Lancellotti, Isabella; Barbieri, Luisa [University of Modena and Reggio Emilia, Department of Engineering “Enzo Ferrari”, Modena (Italy); Spinella, Alberto; Saladino, Maria Luisa [University of Palermo CGA-UniNetLab, Palermo (Italy); Martino, Delia Chillura [University of Palermo, Department STEBICEF, Palermo (Italy); Caponetti, Eugenio [University of Palermo CGA-UniNetLab, Palermo (Italy); University of Palermo, Department STEBICEF, Palermo (Italy); Armetta, Francesco [University of Palermo, Department STEBICEF, Palermo (Italy); Leonelli, Cristina [University of Modena and Reggio Emilia, Department of Engineering “Enzo Ferrari”, Modena (Italy)

2015-04-09

Highlights: • Inertization of chromium liquid waste in aluminosilicate matrix. • Water less inertization technique exploiting the waste water content. • Liquid waste inertization without drying step. • Long term stabilization study through leaching test. • SEM analysis and {sup 29}Si and {sup 27}Al MAS NMR in relation with long curing time. - Abstract: A class of inorganic binders, also known as geopolymers, can be obtained by alkali activation of aluminosilicate powders at room temperature. The process is affected by many parameters (curing time, curing temperature, relative humidity etc.) and leads to a resistant matrix usable for inertization of hazardous waste. In this study an industrial liquid waste containing a high amount of chromium (≈2.3 wt%) in the form of metalorganic salts is inertized into a metakaolin based geopolymer matrix. One of the innovative aspects is the exploitation of the water contained in the waste for the geopolymerization process. This avoided any drying treatment, a common step in the management of liquid hazardous waste. The evolution of the process - from the precursor dissolution to the final geopolymer matrix hardening - of different geopolymers containing a waste amount ranging from 3 to 20% wt and their capability to inertize chromium cations were studied by: i) the leaching tests, according to the EN 12,457 regulation, at different curing times (15, 28, 90 and 540 days) monitoring releases of chromium ions (Cr(III) and Cr(VI)) and the cations constituting the aluminosilicate matrix (Na, Si, Al); ii) the humidity variation for different curing times (15 and 540 days); iii) SEM characterization at different curing times (28 and 540 days); iv) the trend of the solution conductivity and pH during the leaching test; v) the characterization of the short-range ordering in terms of T−O−T bonds (where T is Al or Si) by {sup 29}Si and {sup 27}Al solid state magic-angle spinning nuclear magnetic resonance (ss MAS NMR) for

Broccoli and watercress suppress matrix metalloproteinase-9 activity and invasiveness of human MDA-MB-231 breast cancer cells

International Nuclear Information System (INIS)

Rose, Peter; Huang, Qing; Ong, Choon Nam; Whiteman, Matt

2005-01-01

A high dietary intake of cruciferous vegetables has been associated with a reduction in numerous human pathologies particularly cancer. In the current study, we examined the inhibitory effects of broccoli (Brassica oleracea var. italica) and watercress (Rorripa nasturtium aquaticum) extracts on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cancer cell invasion and matrix metalloproteinase-9 activity using human MDA-MB-231 breast cancer cells. Aberrant overexpression of matrix metalloproteinases, including metalloproteinase-9, is associated with increased invasive potential in cancer cell lines. Our results demonstrate that extracts of broccoli and Rorripa suppressed TPA-induced MMP-9 activity and invasiveness in a concentration dependant manner as determined by zymographic analysis. Furthermore, fractionation of individual extracts followed by liquid chromatography mass spectroscopy analysis (LC-MS) revealed that the inhibitory effects of each vegetable were associated with the presence of 4-methysulfinylbutyl (sulforaphane) and 7-methylsulphinylheptyl isothiocyanates. Taken together, our data indicate that isothiocyanates derived form broccoli and Rorripa inhibit metalloproteinase 9 activities and also suppress the invasive potential of human MDA-MB-231 breast cancer cells in vitro. The inhibitory effects observed in the current study may contribute to the suppression of carcinogenesis by diets high in cruciferous vegetables

Synthesis of block copolymers with well-defined alternating chromophore and flexible spacer for electroluminescence application

Energy Technology Data Exchange (ETDEWEB)

Wang Haiqiao; Sun Qingjiang; Li Yongfang; Li Xiaoyu

2003-02-24

Two novel light-emitting block copolymers, poly[1,4,7,10-tetraoxadecane-1,10-diyl-1,4-naphthalene-1,2-ethenediyl-1,4- phenylene-1,2-ethenediyl-1,4-naphthalene] (TEO-DNVB) and poly[1,4,7,10-tetraoxadecane-1,10-diyl-1,4-naphthalene-1,2-ethenediyl- (2,5-dimethoxy-1,4-phenylene)-1,2-ethenediyl-1,4-naphthalene] (TEO-MDNVB), were synthesized by using the Wittig reaction. The block copolymers are composed of the fluorescent segments, 1,4-di[2-(1-naphthyl) vinyl] benzene (DNVB) or 2,5-dimethyloxy-1,4-di[2-(1-naphthyl) vinyl] benzene (MDNVB) and the flexible segments, tri(ethylene oxide) (TEO). The copolymers were characterized by Fourier transform infrared (FT-IR), {sup 1}H-nuclear magnetic resonance ({sup 1}H-NMR), ultraviolet-visible (UV-Vis), gel permeation chromatography (GPC) and cyclic voltammograms (CV). Thermal properties were investigated with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) under nitrogen atmosphere. Cyclic voltammetric measurement reveals a reversible p-doping process. Efficient blue-green polymer light-emitting diodes (PLEDs) and polymer light-emitting electrochemical cells (PLECs) were successfully fabricated. The synthesis, characterization and the electroluminescent properties of the copolymers are reported in this paper.

Electroluminescence of organic light-emitting diodes with an ultra-thin layer of dopant

Energy Technology Data Exchange (ETDEWEB)

Li Weizhi [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Yu Junsheng [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)], E-mail: jsyu@uestc.edu.cn; Wang, Tao [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Jiang, Yadong [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)], E-mail: jiangyd@uestc.edu.cn; Wei, Bangxiong [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2008-03-15

Conventional fluorescent dyes, i.e., 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB), 5,12-dihydro-5,12-dimethylquino [2,3-b]acridine-7,14-dione (DMQA) and 5,6,11,12-tetraphenylnaphthacene (Rubrene), were used to investigate the performance of organic light-emitting diodes (OLEDs) based on indium tin oxide (ITO)/N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB)/tris-(8-hydroxyquinolate)-aluminum (Alq{sub 3})/MgAg. The dyes were either inserted into devices as an ultra-thin film at the NPB/Alq{sub 3} interface by sequential evaporation, or doped into the Alq{sub 3} emission layer by co-evaporation with the doping ratio about 2%. Electroluminescence (EL) spectra of devices indicated that concentration quenching effect (CQE) of the dye-dopant was slightly bigger in the former than in the latter, while the degrees of CQE for three dopants are in the order of DMQA > DCJTB > Rubrene suggested by the difference in EL spectra and performances of devices. In addition, EL process of device with an ultra-thin layer of dopant is dominated by direct carrier trapping (DCT) process due to almost no holes recombine with electrons in Alq{sub 3}-host layer.

Synthesis, characterization, photophysics and electroluminescence based on a series of pyran-containing emitters

Energy Technology Data Exchange (ETDEWEB)

Yang Lifen [State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing 100871 (China); Guan Min [State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing 100871 (China); Bian Zuqiang [State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing 100871 (China)]. E-mail: bianzq@pku.edu.cn; Xie Junqi [State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing 100871 (China); Chen Tianpeng [State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing 100871 (China); Huang Chunhui [State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing 100871 (China)]. E-mail: chhuang@pku.edu.cn

2006-04-03

Four unsymmetric as well as symmetric carbazole or oxadiazole modified pyran-containing compounds have been synthesized and characterized. These compounds are 4-(dicyanomethylene)-2-methyl-6-(4-(carbazolo-9-yl)phenyl)-4H-pyran (10), 4-(dicyanomethylene)-2,6-bis(4-(carbazolo-9-yl)phenyl)-4H-pyran (11), 4-(dicyanomethylene)-2-methyl-6-(4-tert-phenyl)-1,3,4-oxdiazole-4-phenyl)-4 H-pyran (12), and 4-(dicyanomethylene)-2,6-bis(4-tert-phenyl)-1,3, 4-oxdiazole-4-phenyl-4H-pyran (13). Photoluminescent measurements indicated that their maximal emissions can be tuned from 543 to 590 nm in acetone solution. Electroluminescent studies based on these compounds as dopants resulted in greenish yellow light emission. It was found that the device based on the bis-condensed symmetric compound (11) with the configuration of indium tin oxide / Copper (II) phthalocyanine (5 nm) / N,N'-bis-(1-naphthl)-diphenyl-1,1'-biphenyl-4,4'-diamine (40 nm) / compound (11) : tris-(8-quinolinolato)aluminium (Alq{sub 3}) (1%) (30 nm) / 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (5 nm) / Alq{sub 3} (40 nm) / Mg : Ag (9 : 1) (200 nm) / Ag (80 nm) has achieved the highest luminance (6869 cd/m{sup 2}) and efficiency (1.32 lm/W and 2.52 cd/A) among the four emitters.

New cyclometalated Iridium(III) beta-dicetone complex as phosphorescent dopant in Organic light emitting devices

Science.gov (United States)

Ivanov, P.; Petrova, P.; Stanimirov, S.; Tomova, R.

2017-01-01

A new Bis[4-(benzothiazolato-N,C2‧-2-yl)-N,N-dimethylaniline]Iridium(III) acetylacetonate (Me2N-bt) 2Ir(acac) was synthesized and identified by 1H NMR and elemental analysis. The application of the new compound as a dopant in the hole transporting layer (HTL) of Organic light emitting diode (OLED) structure: HTL/EL/ETL, where HTL was N,N’-bis(3-methylphenyl)-N,N’-diphenylbenzidine (TPD), incorporated in Poly(N-vinylcarbazole) (PVK) matrix, EL - electroluminescent layer of Bis(8-hydroxy-2-methylquinoline)-(4-phenylpheno-xy)aluminum (BAlq) and ETL - electron-transporting layer of Tris-(8-hydroxyquinoline) aluminum (Alq3) or Bis[2-(2-benzothiazoly) phenolato]zinc (Zn(btz)2). We established that the electroluminescent spectra of OLEDs at different concentrations of the dopant were basically the sum of the greenish-blue emission of BAlq and yellowish-green emission of Ir complex. It was found that with increasing of the dopant concentration the relative electroluminescent intensity of Iridium complex emission increased and this of BAlq decreased and as a result the fine tuning of OLED color was observed.

Experiments on multi-stage light intensification by electro-luminescence; Experiences sur l'intensification de la lumiere en cascade par electroluminescence; Opyty po mnogokaskadnomu svetousileniyu (fotoumnozheniyu) posredstvom ehlektrosvecheniya; Experimentos sobre intensificacion en cascada de la luminosidad por electroluminiscencia

Energy Technology Data Exchange (ETDEWEB)

Owaki, K; Nakamura, T [Kobe Kogyo Corporation, Okubo, Akashi, Hyogo (Japan)

1962-04-15

In recent years, several papers on the solid-state image-intensifier by the use of electro-luminescent phosphor and photo-conductive materials have appeared as one of the important applications of solid-state electronics. It is convenient and important to use the solid-state intensifier for light amplification. The purpose of this experimental work is to achieve more amplification by cascading the intensifier in multi-stage. This paper first deals with the electrical and optical characteristics of a single-element lightintensifier, then points out briefly the advantage of employing parallel resistance with an electroluminescent- panel to improve its characteristics. Two types of photo-conductive cell were used, one was a sintered CdS cell and the other a CdS photo-sensitive powder, moulded with plastic binder. According to the results obtained on a single-element light-intensifier, two-stage and threestage light intensifiers were made and their characteristics were tested for various parallel resistances. In the three-stage light intensifier, the amplification of about 400 was obtained at 0.3 rlx in-put radiation, and these results suggest the possibility of obtaining more amplification at lower input radiation. The experimental results are believed to be applicable to a solid-state image-intensifier by devising a suitable construction. (author) [French] Au cours des dernieres annees, on a publie plusieurs communications sur le renforcateur d'images a cristal utilisant le phosphore electroluminescent et des matieres photoconductrices; c'est la une des principales applications de l'electronique de l'etat solide. Il est a la fois pratique et avantageux d'utiliser le renforcateur d'images a cristal pour l'amplification de la lumiere. Ces experiences visent a accroitre l'amplification en faisant cascader le renforcateur en plusieurs phases. Apres avoir presente les caracteristiques electriques et optiques d'un photomultiplicateur a un seul element, les auteurs exposent

Activity concentration measurements of 137Cs, 90Sr and 40K in a wild food matrix reference material (Wild Berries) CCRI(II)-S8

International Nuclear Information System (INIS)

Watjen, U.; Altzitzogloa, T.; Spasova, Y.; Ceccatelli, A.; Kis-Benedek, G.; Dikmen, H.; Gundogdu, G.; Yucel, U.; Ferreux, L.; Frechou, C.; Pierre, S.; Garcia, L.; Moreno, Y.; Oropesa, P.; La Rosa, J.; Luca, A.; Schmiedel, M.; Wershofen, H.; Szucs, L.; Vasile, M.

2014-01-01

In 2009, the CCRI approved a supplementary comparison to be organized by the IRMM as pilot laboratory for the activity concentrations of 137 Cs, 90 Sr and 40 K in a matrix material of dried bilberries. The organization of this comparison and the material and measurement methods used are described. The supplementary comparison reference values (SCRV) for each of the three radionuclides are given together with the degrees of equivalence of each participating laboratory with the SCRV for the specific radionuclide. The results of this supplementary comparison allow the participating NMIs/designated institutes to declare calibration and measurement capabilities (CMCs) for the given radionuclides in a similar type of food matrix, an important aspect given the relatively few supplementary comparisons for activity in matrix materials organized so far. (authors)

Matrix metalloproteinases in exercise and obesity

OpenAIRE

Jaoude, Jonathan; Koh, Yunsuk

2016-01-01

Jonathan Jaoude,1 Yunsuk Koh2 1Department of Biology, 2Department of Health, Human Performance, and Recreation, Baylor University, Waco, TX, USA Abstract: Matrix metalloproteinases (MMPs) are zinc- and calcium-dependent endoproteinases that have the ability to break down extracellular matrix. The large range of MMPs’ functions widens their spectrum of potential role as activators or inhibitors in tissue remodeling, cardiovascular diseases, and obesity. In particular, MMP-1, -2, and ...

Matrix metalloproteinase-12 (MMP-12) in osteoclasts

DEFF Research Database (Denmark)

Hou, Peng; Troen, Tine; Ovejero, Maria C

2004-01-01

Osteoclasts require matrix metalloproteinase (MMP) activity and cathepsin K to resorb bone, but the critical MMP has not been identified. Osteoclasts express MMP-9 and MMP-14, which do not appear limiting for resorption, and the expression of additional MMPs is not clear. MMP-12, also called...... bone show MMP-12 expression in osteoclasts in calvariae and long bones. We also demonstrate that recombinant MMP-12 cleaves the putative functional domains of osteopontin and bone sialoprotein, two bone matrix proteins that strongly influence osteoclast activities, such as attachment, spreading...

Membranes having aligned 1-D nanoparticles in a matrix layer for improved fluid separation

Science.gov (United States)

Revanur, Ravindra; Lulevich, Valentin; Roh, Il Juhn; Klare, Jennifer E.; Kim, Sangil; Noy, Aleksandr; Bakajin, Olgica

2015-12-22

Membranes for fluid separation are disclosed. These membranes have a matrix layer sandwiched between an active layer and a porous support layer. The matrix layer includes 1-D nanoparticles that are vertically aligned in a porous polymer matrix, and which substantially extend through the matrix layer. The active layer provides species-specific transport, while the support layer provides mechanical support. A matrix layer of this type has favorable surface morphology for forming the active layer. Furthermore, the pores that form in the matrix layer tend to be smaller and more evenly distributed as a result of the presence of aligned 1-D nanoparticles. Improved performance of separation membranes of this type is attributed to these effects.

Synthesis and Electroluminescence Properties of 3-(Trifluoromethylphenyl-Substituted 9,10-Diarylanthracene Derivatives for Blue Organic Light-Emitting Diodes

Directory of Open Access Journals (Sweden)

Sang Woo Kwak

2017-10-01

Full Text Available Diaryl-substituted anthracene derivatives containing 3-(trifluoromethylphenyl groups, 9,10-diphenyl-2-(3-(trifluoromethylphenylanthracene (1, 9,10-di([1,1′-biphenyl]-4-yl-2-(3-(trifluoromethylphenylanthracene (2, and 9,10-di(naphthalen-2-yl-2-(3-(trifluoromethylphenylanthracene (3 were synthesized and characterized. The compounds 1–3 possessed high thermal stability and proper frontier-energy levels, which make them suitable as host materials for blue organic light-emitting diodes. The electroluminescent (EL emission maximum of the three N,N-diphenylamino phenyl vinyl biphenyl (DPAVBi-doped (8 wt % devices for compounds 1–3 was exhibited at 488 nm (for 1 and 512 nm (for 2 and 3. Among them, the 1-based device displayed the highest device performances in terms of brightness (Lmax = 2153.5 cd·m−2, current efficiency (2.1 cd·A−1, and external quantum efficiency (0.8%, compared to the 2- and 3-based devices.

Effect of interface voids on electroluminescence colors for ZnO microdisk/p-GaN heterojunction light-emitting diodes

Science.gov (United States)

Mo, Ran; Choi, Ji Eun; Kim, Hyeong Jin; Jeong, Junseok; Kim, Jong Chan; Kim, Yong-Jin; Jeong, Hu Young; Hong, Young Joon

2017-10-01

This study investigates the influence of voids on the electroluminescence (EL) emission color of ZnO microdisk/p-GaN heterojunction light-emitting diodes (LEDs). For this study, position-controlled microdisk arrays were fabricated on patterned p-GaN via wet chemical epitaxy of ZnO, and specifically, the use of trisodium citrate dihydrate (TCD) yielded high-density voids at the bottom of the microdisk. Greenish yellow or whitish blue EL was emitted from the microdisk LEDs formed with or without TCD, respectively, at reverse-bias voltages. Such different EL colors were found to be responsible for the relative EL intensity ratio between indigo and yellow emission peaks, which were originated from radiative recombination at p-GaN and ZnO, respectively. The relative EL intensity between dichromatic emissions is discussed in terms of (i) junction edge effect provoked by interfacial voids and (ii) electron tunneling probability depending on the depletion layer geometry.

The effect of the thicknesses of the various layers on the colour emitted by an organic electroluminescent device

Science.gov (United States)

Jolinat, P.; Clergereaux, R.; Farenc, J.; Destruel, P.

1998-05-01

Organic electroluminescent diodes based on thin organic layers are one of the most promising next-generation systems for the backlighting of the liquid crystal screens. Among other methods to obtain white light, three-layer luminescent devices with each layer emitting one of the three fundamental colours have been studied here. Red, green and blue light were produced by 0022-3727/31/10/018/img1 doped with Nile red, 0022-3727/31/10/018/img1 and TPD layers respectively. A fourth thin film of TAZ has been inserted between TPD and 0022-3727/31/10/018/img1 to control injection of electrons into the TPD. The effect of the layers' thicknesses on the spectral emission of the device has been examined. Results show that the thicknesses of TAZ and doped 0022-3727/31/10/018/img1 layers have to be controlled to within a precision of better than 5 Å. The discussion turns on the possibility of applying this technology to screen backlighting.

Bee venom induces apoptosis and suppresses matrix metaloprotease-2 expression in human glioblastoma cells

Directory of Open Access Journals (Sweden)

Mohsen Sisakht

Full Text Available Abstract Glioblastoma is the most common malignant brain tumor representing with poor prognosis, therapy resistance and high metastasis rate. Increased expression and activity of matrix metalloproteinase-2, a member of matrix metalloproteinase family proteins, has been reported in many cancers including glioblastoma. Inhibition of matrix metalloproteinase-2 expression has resulted in reduced aggression of glioblastoma tumors in several reports. In the present study, we evaluated effect of bee venom on expression and activity of matrix metalloproteinase-2 as well as potential toxicity and apoptogenic properties of bee venom on glioblastoma cells. Human A172 glioblastoma cells were treated with increasing concentrations of bee venom. Then, cell viability, apoptosis, matrix metalloproteinase-2 expression, and matrix metalloproteinase-2 activity were measured using MMT assay, propidium iodide staining, real time-PCR, and zymography, respectively. The IC50 value of bee venom was 28.5 µg/ml in which it leads to decrease of cell viability and induction of apoptosis. Incubation with bee venom also decreased the expression of matrix metalloproteinase-2 in this cell line (p < 0.05. In zymography, there was a reverse correlation between bee venom concentration and total matrix metalloproteinase-2 activity. Induction of apoptosis as well as inhibition of matrix metalloproteinase-2 activity and expression can be suggested as molecular mechanisms involved in cytotoxic and antimetastatic effects of bee venom against glioblastoma cells.

Purely organic thermally activated delayed fluorescence (TADF) materials for organic light-emitting diodes (OLEDs)

OpenAIRE

Wong, Michael Y.; Zysman-Colman, Eli

2017-01-01

We thank the University of St Andrews for support. EZ-C thanks the Leverhulme Trust for financial support (RPG-2016-047). and the EPSRC (EP/P010482/1) for financial support. The design of thermally activated delayed fluorescence (TADF) materials both as emitters and as hosts is an exploding area of research. The replacement of phosphorescent metal complexes with inexpensive organic compounds in electroluminescent (EL) devices that demonstrate comparable performance metrics is paradigm shif...

Synthesis and Electroluminescent Properties of Bis(3H-1,2,3-triazolo-[4,5-b]pyridine-3-olzinc Zn(TAP2

Directory of Open Access Journals (Sweden)

Trinh Dac Hoanh

2012-01-01

Full Text Available A new light-emissive material, bis(3H-1,2,3-triazolo-[4,5-b]pyridine-3-olzinc (Zn(TAP2, has been synthesized and characterized by FT-NMR, FT-IR, UV-Vis, and elemental analysis. The photoluminescence (PL of Zn(TAP2 was measured from the DMF solution at 460 nm. The HOMO (6.5 eV and LUMO (2.8 eV energy levels of Zn(TAP2 were estimated from the measurement of cyclic voltammetry. The devices with structures of ITO/NPB/Zn(TAP2/LiF/Al and ITO/NPB/Zn(TAP2/Alq3/LiF/Al were constructed to investigate their electroluminescent (EL performance. Zn (TAP2 is supposed to be a good emitting material in the EL device.

Enhancement of hole injection and electroluminescence by ordered Ag nanodot array on indium tin oxide anode in organic light emitting diode

Energy Technology Data Exchange (ETDEWEB)

Jung, Mi, E-mail: jmnano00@gmail.com, E-mail: Dockha@kist.re.kr [Sensor System Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); School of Mechanical Systems Engineering, Kookmin University, Seoul 136-702 (Korea, Republic of); Mo Yoon, Dang; Kim, Miyoung [Korea Printed Electronics Center, Korea Electronics Technology Institute, Jeollabuk-do, 561-844 (Korea, Republic of); Kim, Chulki; Lee, Taikjin; Hun Kim, Jae; Lee, Seok; Woo, Deokha, E-mail: jmnano00@gmail.com, E-mail: Dockha@kist.re.kr [Sensor System Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lim, Si-Hyung [School of Mechanical Systems Engineering, Kookmin University, Seoul 136-702 (Korea, Republic of)

2014-07-07

We report the enhancement of hole injection and electroluminescence (EL) in an organic light emitting diode (OLED) with an ordered Ag nanodot array on indium-tin-oxide (ITO) anode. Until now, most researches have focused on the improved performance of OLEDs by plasmonic effects of metal nanoparticles due to the difficulty in fabricating metal nanodot arrays. A well-ordered Ag nanodot array is fabricated on the ITO anode of OLED using the nanoporous alumina as an evaporation mask. The OLED device with Ag nanodot arrays on the ITO anode shows higher current density and EL enhancement than the one without any nano-structure. These results suggest that the Ag nanodot array with the plasmonic effect has potential as one of attractive approaches to enhance the hole injection and EL in the application of the OLEDs.

High performance organic transistor active-matrix driver developed on paper substrate

Science.gov (United States)

Peng, Boyu; Ren, Xiaochen; Wang, Zongrong; Wang, Xinyu; Roberts, Robert C.; Chan, Paddy K. L.

2014-09-01

The fabrication of electronic circuits on unconventional substrates largely broadens their application areas. For example, green electronics achieved through utilization of biodegradable or recyclable substrates, can mitigate the solid waste problems that arise at the end of their lifespan. Here, we combine screen-printing, high precision laser drilling and thermal evaporation, to fabricate organic field effect transistor (OFET) active-matrix (AM) arrays onto standard printer paper. The devices show a mobility and on/off ratio as high as 0.56 cm2V-1s-1 and 109 respectively. Small electrode overlap gives rise to a cut-off frequency of 39 kHz, which supports that our AM array is suitable for novel practical applications. We demonstrate an 8 × 8 AM light emitting diode (LED) driver with programmable scanning and information display functions. The AM array structure has excellent potential for scaling up.

A matrix-inversion method for gamma-source mapping from gamma-count data - 59082

International Nuclear Information System (INIS)

Bull, Richard K.; Adsley, Ian; Burgess, Claire

2012-01-01

Gamma ray counting is often used to survey the distribution of active waste material in various locations. Ideally the output from such surveys would be a map of the activity of the waste. In this paper a simple matrix-inversion method is presented. This allows an array of gamma-count data to be converted to an array of source activities. For each survey area the response matrix is computed using the gamma-shielding code Microshield [1]. This matrix links the activity array to the count array. The activity array is then obtained via matrix inversion. The method was tested on artificially-created arrays of count-data onto which statistical noise had been added. The method was able to reproduce, quite faithfully, the original activity distribution used to generate the dataset. The method has been applied to a number of practical cases, including the distribution of activated objects in a hot cell and to activated Nimonic springs amongst fuel-element debris in vaults at a nuclear plant. (authors)

Physiology and pathophysiology of matrix metalloproteases

NARCIS (Netherlands)

Klein, T.; Bischoff, R.

Matrix metalloproteases (MMPs) comprise a family of enzymes that cleave protein substrates based on a conserved mechanism involving activation of an active site-bound water molecule by a Zn(2+) ion. Although the catalytic domain of MMPs is structurally highly similar, there are many differences with

Physiology and pathophysiology of matrix metalloproteases

NARCIS (Netherlands)

Klein, T; Bischoff, Rainer

2010-01-01

Matrix metalloproteases (MMPs) comprise a family of enzymes that cleave protein substrates based on a conserved mechanism involving activation of an active site-bound water molecule by a Zn(2+) ion. Although the catalytic domain of MMPs is structurally highly similar, there are many differences with

ACORNS, Covariance and Correlation Matrix Diagonalization

International Nuclear Information System (INIS)

Szondi, E.J.

1990-01-01

1 - Description of program or function: The program allows the user to verify the different types of covariance/correlation matrices used in the activation neutron spectrometry. 2 - Method of solution: The program performs the diagonalization of the input covariance/relative covariance/correlation matrices. The Eigen values are then analyzed to determine the rank of the matrices. If the Eigen vectors of the pertinent correlation matrix have also been calculated, the program can perform a complete factor analysis (generation of the factor matrix and its rotation in Kaiser's 'varimax' sense to select the origin of the correlations). 3 - Restrictions on the complexity of the problem: Matrix size is limited to 60 on PDP and to 100 on IBM PC/AT

Development of an integrated system for activity-based profiling of matrix metallo-proteases

NARCIS (Netherlands)

Freije, Jan Robert

2006-01-01

Matrix metallo-proteases constitute a family of extracellular zinc-dependent endopeptidases that are involved in degradation of extracellular matrix (ECM) components and other bioactive non-ECM molecules. A plethora of studies have implicated important roles for MMPs in many diseases (including

Zinc Cadmium Selenide Cladded Quantum Dot Based Electroluminescent and Nonvolatile Memory Devices

Science.gov (United States)

Al-Amody, Fuad H.

This dissertation presents electroluminescent (EL) and nonvolatile memory devices fabricated using pseudomorphic ZnCdSe-based cladded quantum dots (QDs). These dots were grown using our own in-school built novel reactor. The EL device was fabricated on a substrate of ITO (indium tin oxide) coated glass with the quantum dots sandwiched between anode and cathode contacts with a small barrier layer on top of the QDs. The importance of these cladded dots is to increase the quantum yield of device. This device is unique as they utilize quantum dots that are pseudomorphic (nearly lattice-matched core and the shell of the dot). In the case of floating quantum dot gate nonvolatile memory, cladded ZnCdSe quantum dots are deposited on single crystalline gate insulator (ZnMgS/ZnMgSe), which is grown using metal-organic chemical vapor deposition (MOCVD). The control gate dielectric layer of the nonvolatile memory is Si3N4 or SiO2 and is grown using plasma enhanced chemical vapor deposition (PECVD). The cladded dots are grown using an improved methodology of photo-assisted microwave plasma metal-organic chemical vapor deposition (PMP-MOCVD) enhanced reactor. The cladding composition of the core and shell of the dots was engineered by the help of ultraviolet light which changed the incorporation of zinc (and hence composition of ZnCdSe). This makes ZnxCd1--xSe-ZnyCd1--y Se QDs to have a low composition of zinc in the core than the cladding (x

Treatment of active unicameral bone cysts with percutaneous injection of demineralized bone matrix and autogenous bone marrow.

Science.gov (United States)

Rougraff, Bruce T; Kling, Thomas J

2002-06-01

The treatment of unicameral bone cysts varies from open bone-grafting procedures to percutaneous injection of corticosteroids or bone marrow. The purpose of this study was to evaluate the feasibility and effectiveness of percutaneous injection of a mixture of demineralized bone matrix and autogenous bone marrow for the treatment of simple bone cysts. Twenty-three patients with an active unicameral bone cyst were treated with trephination and injection of allogeneic demineralized bone matrix and autogenous bone marrow. The patients were followed for an average of fifty months (range, thirty to eighty-one months), at which time pain, function, and radiographic signs of resolution of the cyst were assessed. The average time until the patients had pain relief was five weeks, and the average time until the patients returned to full, unrestricted activities was six weeks. Bone-healing at the site of the injection was first seen radiographically at three to six months. No patient had a pathologic fracture during this early bone-healing stage. Cortical remodeling was seen radiographically by six to nine months, and after one year the response was usually complete, changing very little from then on. Five patients required a second injection because of recurrence of the cyst, and all five had a clinically and radiographically quiescent cyst after an average of thirty-six additional months of follow-up. Seven of the twenty-three patients had incomplete healing manifested by small, persistent radiolucent areas within the original cyst. None of these cysts increased in size or resulted in pain or fracture. Percutaneous injection of allogeneic demineralized bone matrix and autogenous bone marrow is an effective treatment for unicameral bone cysts.

Collagenolytic Matrix Metalloproteinase Activities toward Peptomeric Triple-Helical Substrates.

Science.gov (United States)

Stawikowski, Maciej J; Stawikowska, Roma; Fields, Gregg B

2015-05-19

Although collagenolytic matrix metalloproteinases (MMPs) possess common domain organizations, there are subtle differences in their processing of collagenous triple-helical substrates. In this study, we have incorporated peptoid residues into collagen model triple-helical peptides and examined MMP activities toward these peptomeric chimeras. Several different peptoid residues were incorporated into triple-helical substrates at subsites P3, P1, P1', and P10' individually or in combination, and the effects of the peptoid residues were evaluated on the activities of full-length MMP-1, MMP-8, MMP-13, and MMP-14/MT1-MMP. Most peptomers showed little discrimination between MMPs. However, a peptomer containing N-methyl Gly (sarcosine) in the P1' subsite and N-isobutyl Gly (NLeu) in the P10' subsite was hydrolyzed efficiently only by MMP-13 [nomenclature relative to the α1(I)772-786 sequence]. Cleavage site analysis showed hydrolysis at the Gly-Gln bond, indicating a shifted binding of the triple helix compared to the parent sequence. Favorable hydrolysis by MMP-13 was not due to sequence specificity or instability of the substrate triple helix but rather was based on the specific interactions of the P7' peptoid residue with the MMP-13 hemopexin-like domain. A fluorescence resonance energy transfer triple-helical peptomer was constructed and found to be readily processed by MMP-13, not cleaved by MMP-1 and MMP-8, and weakly hydrolyzed by MT1-MMP. The influence of the triple-helical structure containing peptoid residues on the interaction between MMP subsites and individual substrate residues may provide additional information about the mechanism of collagenolysis, the understanding of collagen specificity, and the design of selective MMP probes.

Monolithic Active Pixel Matrix with Binary Counters (MAMBO) ASIC

International Nuclear Information System (INIS)

Khalid, Farah F.; Deptuch, Grzegorz; Shenai, Alpana; Yarema, Raymond J.

2010-01-01

Monolithic Active Matrix with Binary Counters (MAMBO) is a counting ASIC designed for detecting and measuring low energy X-rays from 6-12 keV. Each pixel contains analogue functionality implemented with a charge preamplifier, CR-RC 2 shaper and a baseline restorer. It also contains a window comparator which can be trimmed by 4 bit DACs to remove systematic offsets. The hits are registered by a 12 bit ripple counter which is reconfigured as a shift register to serially output the data from the entire ASIC. Each pixel can be tested individually. Two diverse approaches have been used to prevent coupling between the detector and electronics in MAMBO III and MAMBO IV. MAMBO III is a 3D ASIC, the bottom ASIC consists of diodes which are connected to the top ASIC using μ-bump bonds. The detector is decoupled from the electronics by physically separating them on two tiers and using several metal layers as a shield. MAMBO IV is a monolithic structure which uses a nested well approach to isolate the detector from the electronics. The ASICs are being fabricated using the SOI 0.2 (micro)m OKI process, MAMBO III is 3D bonded at T-Micro and MAMBO IV nested well structure was developed in collaboration between OKI and Fermilab.

Interfacial exciplex electroluminescence between diamine derivatives with starburst molecular structure and tris(acetylacetonato)-(mono-phenothroline) thulium

Energy Technology Data Exchange (ETDEWEB)

He Hong [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Li Wenlian [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)], E-mail: wllioel@yahoo.com.cn; Su Zisheng; Chu Bei; Bi Defeng; Chen Yiren; Wang Dan; Su Wenming; Li Bin [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)

2009-02-20

The authors demonstrate the interfacial exciplex electroluminescence (EL) between tris(acetylacetonato)-(mono-phenothroline) thulium [Tm(AcA){sub 3}phen] and two diamine derivatives with starburst molecular structure- 4,4',4''-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA) and 4,4',4''-tris[3-methyl-pheny(phenyl)-amino]triphenyl-amine (m-MTDATA), both of which have the same ionization potential (IP) (approximately 5.1 eV). When the Tm-complex and the two diamine derivatives are respectively used as the electron accepter and donors, the two EL devices exhibit different exciplex emissions, which verifies our previously reported opinion regarding the effect of the different substitutes on exciplex emission [W.M. Su, W.L. Li, Q. Xin, Z.S. Su, B. Chu, D.F. Bi, H. He, J.H. Niu, Appl. Phys. Lett. 91 (2007) 043508]. When the mixture of the two diamine derivatives is used as a donor, a white EL device with the Commission International de l'Eclairage (CIE) coordinates of (0.277, 0.323) is achieved. The exciplex formation mechanisms of the devices with the two different donors are discussed.

Study of the electroluminescence of highly stereoregular poly(N-pentenyl-carbazole) for blue and white OLEDs

Science.gov (United States)

Liguori, R.; Botta, A.; Pragliola, S.; Rubino, A.; Venditto, V.; Velardo, A.; Aprano, S.; Maglione, M. G.; Prontera, C. T.; De Girolamo Del Mauro, A.; Fasolino, T.; Minarini, C.

2017-06-01

The electroluminescence (EL) of isotactic and syndiotactic poly(N-pentenyl-carbazole) (PPK), achieved by coordination polymerization, is studied in order to investigate the interrelation between the polymer tacticity and their physical-chemical properties. The use of these polymers in organic light-emitting diode (OLED) fabrication is also explored. Thermal and x-ray diffraction analyses of PPKs show that the isotactic stereoisomer is semicrystalline, whereas the syndiotactic one is amorphous. Optical analysis of both stereoisomers, carried out on film samples, reveals the presence of two different excimers: ‘sandwich-like’ and ‘partially overlapping’. Nevertheless, the emission intensity ratio between ‘sandwich-like’ and ‘partially overlapping’ excimers is higher in the isotactic than in the syndiotactic stereoisomer. Using the synthesized polymers as OLED emitting layers, the influence of the polymer tacticity on the EL properties of the device is highlighted. In detail, while blue OLEDs are obtained by using the syndiotactic stereoisomer, OLEDs with a multilayer structure fabricated with the isotactic stereoisomer emit white light. The contribution of three different emissions (fluorescence, phosphorescence and electromer emissions) with comparable intensities to the detected white light is discussed.

Synthesis and photophysical characteristics of 2,7-fluorenevinylene-based trimers and their electroluminescence.

Science.gov (United States)

Mikroyannidis, John A; Fenenko, Larysa; Adachi, Chihaya

2006-10-19

Three new 2,7-fluorenevinylene-based trimers were synthesized and characterized. The synthesis was carried out by the Heck coupling reaction of 9,9-dihexyl-2,7-divinylfluorene with 2-(4-bromophenyl)-5-phenyl-1,3,4-oxadiazole, N,N-diphenyl-4-bromoaniline, or 3-bromopyrene to afford the trimers OXD, TPA, and PYR, respectively. All the trimers were readily soluble in common organic solvents such as tetrahydrofuran, dichloromethane, chloroform, and toluene. Their glass transition temperatures ranged from 33 to 60 degrees C. The UV-vis spectra showed an absorption maximum at lambda(a,max) = 379-417 nm with optical band gap of Eg = 2.47-2.66 eV. In solution, they emitted strong blue-green photoluminescence (PL) with PL maximum at lambda(f,max) = 455-565 nm and fluorescence quantum yield of Phi(f) = 0.65-0.74. On the other hand, in their spin-coated films, the PL efficiencies significantly decreased due to the presence of concentration quenching. All samples showed nanosecond transient lifetime containing two components, suggesting excimer formation. The organic light-emitting diodes (OLEDs) with OXD and TPA showed green emission with electroluminescence (EL) quantum efficiencies of eta(EL) approximately 10(-2)%, while very weak EL efficiency of eta(EL) approximately 10(-5)% was observed with PYR. The highest occupied molecular orbital (HOMO) levels of the films were found to be 5.05-5.75 eV.

Matrix product operators, matrix product states, and ab initio density matrix renormalization group algorithms

Science.gov (United States)

Chan, Garnet Kin-Lic; Keselman, Anna; Nakatani, Naoki; Li, Zhendong; White, Steven R.

2016-07-01

Current descriptions of the ab initio density matrix renormalization group (DMRG) algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational parallelism. The connections and correspondences described here serve to link the future developments with the past and are important in the efficient implementation of continuing advances in ab initio DMRG and related algorithms.

Electroluminescence pulse shape and electron diffusion in liquid argon measured in a dual-phase TPC

Energy Technology Data Exchange (ETDEWEB)

Agnes, P.; et al.

2018-02-05

We report the measurement of the longitudinal diffusion constant in liquid argon with the DarkSide-50 dual-phase time projection chamber. The measurement is performed at drift electric fields of 100 V/cm, 150 V/cm, and 200 V/cm using high statistics $^{39}$Ar decays from atmospheric argon. We derive an expression to describe the pulse shape of the electroluminescence signal (S2) in dual-phase TPCs. The derived S2 pulse shape is fit to events from the uppermost portion of the TPC in order to characterize the radial dependence of the signal. The results are provided as inputs to the measurement of the longitudinal diffusion constant DL, which we find to be (4.12 $\\pm$ 0.04) cm$^2$/s for a selection of 140keV electron recoil events in 200V/cm drift field and 2.8kV/cm extraction field. To study the systematics of our measurement we examine datasets of varying event energy, field strength, and detector volume yielding a weighted average value for the diffusion constant of (4.09 $\\pm$ 0.09) cm$^2$ /s. The measured longitudinal diffusion constant is observed to have an energy dependence, and within the studied energy range the result is systematically lower than other results in the literature.

Influence of photo-generated carriers on current spreading in double diode structures for electroluminescent cooling

Science.gov (United States)

Radevici, Ivan; Tiira, Jonna; Sadi, Toufik; Oksanen, Jani

2018-05-01

Current crowding close to electrical contacts is a common challenge in all optoelectronic devices containing thin current spreading layers (CSLs). We analyze the effects of current spreading on the operation of the so-called double diode structure (DDS), consisting of a light emitting diode (LED) and a photodiode (PD) fabricated within the same epitaxial growth process, and providing an attractive platform for studying electroluminescent (EL) cooling under high bias conditions. We show that current spreading in the common n-type layer between the LED and the PD can be dramatically improved by the strong optical coupling between the diodes, as the coupling enables a photo-generated current through the PD. This reduces the current in the DDS CSL and enables the study of EL cooling using structures that are not limited by the conventional light extraction challenges encountered in normal LEDs. The current spreading in the structures is studied using optical imaging techniques, electrical measurements, simulations, as well as simple equivalent circuit models developed for this purpose. The improved current spreading leads further to a mutual dependence with the coupling efficiency, which is expected to facilitate the process of optimizing the DDS. We also report a new improved value of 63% for the DDS coupling quantum efficiency.

X-RAY ACTIVE MATRIX PIXEL SENSORS BASEDON J-FET TECHNOLOGY DEVELOPED FOR THE LINAC COHERENT LIGHT SOURCE.

Energy Technology Data Exchange (ETDEWEB)

CARINI,G.A.; CHEN, W.; LI, Z.; REHAK, P.; SIDDONS, D.P.

2007-10-29

An X-ray Active Matrix Pixel Sensor (XAMPS) is being developed for recording data for the X-ray Pump Probe experiment at the Linac Coherent Light Source (LCLS). Special attention has to be paid to some technological challenges that this design presents. New processes were developed and refined to address problems encountered during previous productions of XAMPS. The development of these critical steps and corresponding tests results are reported here.

Ultraviolet electroluminescence from nitrogen-doped ZnO-based heterojuntion light-emitting diodes prepared by remote plasma in situ atomic layer-doping technique.

Science.gov (United States)

Chien, Jui-Fen; Liao, Hua-Yang; Yu, Sheng-Fu; Lin, Ray-Ming; Shiojiri, Makoto; Shyue, Jing-Jong; Chen, Miin-Jang

2013-01-23

Remote plasma in situ atomic layer doping technique was applied to prepare an n-type nitrogen-doped ZnO (n-ZnO:N) layer upon p-type magnesium-doped GaN (p-GaN:Mg) to fabricate the n-ZnO:N/p-GaN:Mg heterojuntion light-emitting diodes. The room-temperature electroluminescence exhibits a dominant ultraviolet peak at λ ≈ 370 nm from ZnO band-edge emission and suppressed luminescence from GaN, as a result of the decrease in electron concentration in ZnO and reduced electron injection from n-ZnO:N to p-GaN:Mg because of the nitrogen incorporation. The result indicates that the in situ atomic layer doping technique is an effective approach to tailoring the electrical properties of materials in device applications.

Epithermal neutron activation analysis of blue-green algae Spirulina Platensis as a matrix for selenium-containing pharmaceuticals

International Nuclear Information System (INIS)

Mosulishvili, L.M.; Kirkesali, E.I.; Belokobyl'skij, A.I.; Khizanishvili, A.I.; Frontas'eva, M.V.; Gundorina, S.F.; Oprea, C.D.

2000-01-01

To evaluate the potentiality of the blue-green algae Spirulina Platensis as a matrix for the production of Se-containing pharmaceuticals, the background levels of 31 major, minor and trace elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni (using (n,p)-reaction), As, Br, Zn, Rb, Mo, Ag, Sb, I, Ba, Sm, Tb, Tm, Hf, Ta, W, Au, Hg, Th) in Spirulina Platensis biomass were determined by means of epithermal neutron activation analysis. The possibility of the purpose-oriented incorporation of Se into Spirulina Platensis biomass was demonstrated. The polynomial dependence of the Se accumulation on nutritional medium loading was revealed. The employed analytical technique allows one to reliably control the amount of toxic elements in algae Spirulina Platensis. Based on this study, a conclusion of the possibility to use Spirulina Platensis as a matrix for the production of Se-containing pharmaceuticals was drawn

Matrix precipitation: a general strategy to eliminate matrix interference for pharmaceutical toxic impurities analysis.

Science.gov (United States)

Yang, Xiaojing; Xiong, Xuewu; Cao, Ji; Luan, Baolei; Liu, Yongjun; Liu, Guozhu; Zhang, Lei

2015-01-30

Matrix interference, which can lead to false positive/negative results, contamination of injector or separation column, incompatibility between sample solution and the selected analytical instrument, and response inhibition or even quenching, is commonly suffered for the analysis of trace level toxic impurities in drug substance. In this study, a simple matrix precipitation strategy is proposed to eliminate or minimize the above stated matrix interference problems. Generally, a sample of active pharmaceutical ingredients (APIs) is dissolved in an appropriate solvent to achieve the desired high concentration and then an anti-solvent is added to precipitate the matrix substance. As a result, the target analyte is extracted into the mixed solution with very less residual of APIs. This strategy has the characteristics of simple manipulation, high recovery and excellent anti-interference capability. It was found that the precipitation ratio (R, representing the ability to remove matrix substance) and the proportion of solvent (the one used to dissolve APIs) in final solution (P, affecting R and also affecting the method sensitivity) are two important factors of the precipitation process. The correlation between R and P was investigated by performing precipitation with various APIs in different solvent/anti-solvent systems. After a detailed mathematical reasoning process, P=20% was proved to be an effective and robust condition to perform the precipitation strategy. The precipitation method with P=20% can be used as a general strategy for toxic impurity analysis in APIs. Finally, several typical examples are described in this article, where the challenging matrix interference issues have been resolved successfully. Copyright © 2014 Elsevier B.V. All rights reserved.

Curcumin: a potential candidate for matrix metalloproteinase inhibitors.

Science.gov (United States)

Kumar, Dileep; Kumar, Manish; Saravanan, Chinnadurai; Singh, Sushil Kumar

2012-10-01

Curcumin, a natural yellow pigment of turmeric, has become focus of interest with regard to its role in regulation of matrix metalloproteinases (MMPs). MMPs are metal-dependent endopeptidases capable of degrading components of the extracellular matrix. MMPs are involved in chronic diseases such as arthritis, Alzheimer's disease, psoriasis, chronic obstructive pulmonary disease, asthma, cancer, neuropathic pain, and atherosclerosis. Curcumin regulates the expression and secretion of various MMPs. This review documents the matrix metalloproteinase inhibitory activity of curcumin on various diseases viz., cancer, arthritis, and ulcer. Finally, the steps to be taken for getting potent curcuminoids have also been discussed in the structure-activity relationship (SAR) section. From this review, readers can get answer to the question: Is curcumin a potential MMPI candidate? Numerous approaches have been taken to beget a molecule with specificity restricted to a particular MMP as well as good oral bioavailability; however, nearly all the molecules lack these criteria. Using quantitative structure-activity relationship (QSAR) modeling and virtual screening, new analogs of curcumin can be designed which will be selectively inhibiting different MMPs.

TIMP-1 resistant matrix metalloproteinase-9 is the predominant serum active isoform associated with MRI activity in patients with multiple sclerosis.

Science.gov (United States)

Trentini, Alessandro; Manfrinato, Maria C; Castellazzi, Massimiliano; Tamborino, Carmine; Roversi, Gloria; Volta, Carlo A; Baldi, Eleonora; Tola, Maria R; Granieri, Enrico; Dallocchio, Franco; Bellini, Tiziana; Fainardi, Enrico

2015-08-01

The activity of matrix metalloproteinase-9 (MMP-9) depends on two isoforms, an 82 kDa active MMP-9 modulated by its specific tissue inhibitor (TIMP-1), and a 65 kDa TIMP-1 resistant active MMP-9. The relevance of these two enzymatic isoforms in multiple sclerosis (MS) is still unknown. To investigate the contribution of the TIMP-1 modulated and resistant active MMP-9 isoforms to MS pathogenesis. We measured the serum levels of the 82 kDa and TIMP-1 resistant active MMP-9 isoforms by activity assay systems in 86 relapsing-remitting MS (RRMS) patients, categorized according to clinical and magnetic resonance imaging (MRI) evidence of disease activity, and in 70 inflammatory (OIND) and 69 non-inflammatory (NIND) controls. Serum levels of TIMP-1 resistant MMP-9 were more elevated in MS patients than in OIND and NIND (p < 0.05, p < 0.02, respectively). Conversely, 82 kDa active MMP-9 was higher in NIND than in the OIND and MS patients (p < 0.01 and p < 0.00001, respectively). MRI-active patients had higher levels of TIMP-1 resistant MMP-9 and 82 kDa active MMP-9, than did those with MRI inactive MS (p < 0.01 and p < 0.05, respectively). Our findings suggested that the TIMP-1 resistant MMP-9 seem to be the predominantly active isoform contributing to MS disease activity. © The Author(s), 2015.

Direct Probing of Carrier Behavior in Electroluminescence Indium-Zinc-Oxide/N,N '-Di-[(1-naphthyl)-N,N '-diphenyl]-(1,1'-biphenyl)-4,4'-diamine/Tris(8-hydroxy-quinolinato)aluminum(III)/LiF/Al Diode by Time-Resolved Optical Second-Harmonic Generation

Science.gov (United States)

Taguchi, Dai; Zhang, Le; Li, Jun; Weis, Martin; Manaka, Takaaki; Iwamoto, Mitsumasa

2011-04-01

By using electric-field-induced second-harmonic generation (EFISHG) measurement, we probed charging and discharging in an α-NPD/Alq3 organic light-emitting diode [α-NPD, N,N '-di-[(1-naphthyl)-N,N '-diphenyl]-(1,1'-biphenyl)-4,4'-diamine; Alq3, tris(8-hydroxy-quinolinato)aluminum(III)] while electroluminescence response was monitored. The EFISHG measurement showed that excessive positive charges accumulated at the α-NPD/Alq3 interface in the charging process, accompanying electroluminescence (EL) radiation, and the accumulated excess positive charges disappeared in the discharging process before the EL decayed. Note that the EL radiation was smooth and strong under the high voltage application, while the EL decayed in a similar way. The Maxwell-Wagner model analysis showed no-dependence of the accumulated excessive positive charge on the applied external voltage, suggesting that electrons and holes injected from the opposite electrodes for EL radiation balanced at the interface. The EFISHG measurement will be useful as a direct way to probe carrier behaviors in organic EL devices.

Relationships between junction temperature, electroluminescence spectrum and ageing of light-emitting diodes

Science.gov (United States)

Vaskuri, Anna; Kärhä, Petri; Baumgartner, Hans; Kantamaa, Olli; Pulli, Tomi; Poikonen, Tuomas; Ikonen, Erkki

2018-04-01

We have developed spectral models describing the electroluminescence spectra of AlGaInP and InGaN light-emitting diodes (LEDs) consisting of the Maxwell-Boltzmann distribution and the effective joint density of states. One spectrum at a known temperature for one LED specimen is needed for calibrating the model parameters of each LED type. Then, the model can be used for determining the junction temperature optically from the spectral measurement, because the junction temperature is one of the free parameters. We validated the models using, in total, 53 spectra of three red AlGaInP LED specimens and 72 spectra of three blue InGaN LED specimens measured at various current levels and temperatures between 303 K and 398 K. For all the spectra of red LEDs, the standard deviation between the modelled and measured junction temperatures was only 2.4 K. InGaN LEDs have a more complex effective joint density of states. For the blue LEDs, the corresponding standard deviation was 11.2 K, but it decreased to 3.5 K when each LED specimen was calibrated separately. The method of determining junction temperature was further tested on white InGaN LEDs with luminophore coating and LED lamps. The average standard deviation was 8 K for white InGaN LED types. We have six years of ageing data available for a set of LED lamps and we estimated the junction temperatures of these lamps with respect to their ageing times. It was found that the LEDs operating at higher junction temperatures were frequently more damaged.

New cyclometalated iridium(III) complex as a phosphorescent dopant in organic light emitting devices

Science.gov (United States)

Ivanov, P.; Tomova, R.; Petrova, P.; Stanimirov, S.; Petkov, I.

2014-05-01

A new cyclometalated iridium (III) bis[2-(4-chlorophenyl)benzothiazolato-N,C2]-acetylacetonate, (Cl-bt)2Ir(acac), was synthesized and identified by 1H NMR and elemental analysis. The application was studied of the new compound as a dopant in the hole transporting layer (HTL) of the following organic light emitting diode (OLED) structure: HTL/EL/ETL, where HTL was 4,4'-bis(9H-carbazol-9-yl)biphenyl (CBP) or N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD), incorporated in a poly(N-vinylcarbazole) (PVK) matrix; EL was an electroluminescent layer of bis(8-hydroxy-2-methylquinoline)-(4-phenylpheno-xy) aluminum (BAlq); and ETL was an electron-transporting layer of bis[2-(2-benzothiazoly) phenolato]zinc(II) (Zn(btz)2). We established that the electroluminescence spectra of the OLEDs at different dopant concentrations were basically the sum of the greenish-blue emission of BAlq and the yellowish-green emission of the Ir complex. It was also found that increasing the dopant concentration resulted in an increase in the relative electroluminescent intensity of the Ir complex emission, while that of BAlq decreased, thus a fine tuning of the OLED color was observed.

Identification of matrix metalloproteinase-2 and -9 activities within the intestinal mucosa of dogs with chronic enteropathies.

Science.gov (United States)

Hanifeh, Mohsen; Rajamäki, Minna Marjaana; Syrjä, Pernilla; Mäkitalo, Laura; Kilpinen, Susanne; Spillmann, Thomas

2018-03-12

Matrix metalloproteinases (MMPs) 2 and 9 are zinc- and calcium-dependent endopeptidases involved in the breakdown and reconstitution of extracellular matrix under both physiological and pathological conditions. Mucosal MMP-2 and -9 activities have been reported to be upregulated in the intestine of humans with inflammatory bowel disease (IBD), and in animal models of IBD. However, their involvement in the pathogenesis of canine chronic enteropathies (CE) is unknown. This study investigated mucosal pro- and active MMP-2 and -9 activities in dogs with CE and healthy dogs using gelatin zymography, and also to determine the association of their activities in dogs with CE with the canine IBD activity index (CIBDAI), histopathologic findings, the clinical outcome, and hypoalbuminemia. Intestinal mucosal samples from duodenum, ileum, colon, and cecum were collected from 40 dogs with CE and 18 healthy Beagle dogs. In dogs with CE, the number of samples positive for mucosal pro- and active MMP-2 was significantly higher in the duodenum (P < 0.0001 and P = 0.011, respectively), ileum (P = 0.002 and P = 0.018, respectively), and colon (P < 0.0001 and P = 0.002, respectively), compared with healthy controls. Mucosal pro-MMP-9-positive samples in the duodenum and colon were significantly more frequent in dogs with CE than in healthy dogs (P = 0.0004 and P = 0.001, respectively). Despite the presence of mucosal samples positive for active MMP-9 in the intestinal segments of dogs with CE, the difference compared to healthy controls did not reach statistical significance. None of the intestinal mucosal samples in healthy dogs showed gelatinolytic activity corresponding to the control bands of active MMP-2 and -9. Mucosal active MMP-9 activities displayed a significant positive association with the severity of neutrophil infiltration in the duodenum (P = 00.040), eosinophils in the cecum (P = 00.037), and the CIBDAI score for ileum samples

The exopolysaccharide matrix: a virulence determinant of cariogenic biofilm.

Science.gov (United States)

Koo, H; Falsetta, M L; Klein, M I

2013-12-01

Many infectious diseases in humans are caused or exacerbated by biofilms. Dental caries is a prime example of a biofilm-dependent disease, resulting from interactions of microorganisms, host factors, and diet (sugars), which modulate the dynamic formation of biofilms on tooth surfaces. All biofilms have a microbial-derived extracellular matrix as an essential constituent. The exopolysaccharides formed through interactions between sucrose- (and starch-) and Streptococcus mutans-derived exoenzymes present in the pellicle and on microbial surfaces (including non-mutans) provide binding sites for cariogenic and other organisms. The polymers formed in situ enmesh the microorganisms while forming a matrix facilitating the assembly of three-dimensional (3D) multicellular structures that encompass a series of microenvironments and are firmly attached to teeth. The metabolic activity of microbes embedded in this exopolysaccharide-rich and diffusion-limiting matrix leads to acidification of the milieu and, eventually, acid-dissolution of enamel. Here, we discuss recent advances concerning spatio-temporal development of the exopolysaccharide matrix and its essential role in the pathogenesis of dental caries. We focus on how the matrix serves as a 3D scaffold for biofilm assembly while creating spatial heterogeneities and low-pH microenvironments/niches. Further understanding on how the matrix modulates microbial activity and virulence expression could lead to new approaches to control cariogenic biofilms.

Effect of flavones on rat brain and lung matrix metalloproteinase activity measured by film in-situ zymography.

Science.gov (United States)

Sasaki, K; Tateoka, N; Ando, H; Yoshizaki, F

2005-04-01

We have evaluated the inhibitory activity of flavone, nobiletin, and heptamethoxyflavone on matrix metalloproteinase (MMP) activity in the rat. MMP in 9000-g supernatant fraction of lung homogenate was activated by p-aminophenyl mercuric acetate (APMA), and gelatinolytic activity was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by Coomassie staining. This activity should be related to MMP-2 and/or MMP-9 and was confirmed by gelatin zymography. Fluorescent-conjugated collagen used as a substrate for collagenolytic activity wasinvestigated by SDS-PAGE also. The film in-situ zymography method was applied to rat brain and lung tissue in the same manner. Flavone and nobiletin inhibited the APMA-stimulated gelatinolytic activity and also the collagenolytic activity by more than 75%. The film in-situ zymography method indicated that these compounds might be potent inhibitors of MMP, suggesting the specific inhibition of localized MMP in brain hippocampus and/or lung terminal bronchioles, which may contribute to the prevention of some types of brain disease or cancer invasion and metastasis.

Monolithic Active Pixel Matrix with Binary Counters (MAMBO) ASIC

Energy Technology Data Exchange (ETDEWEB)

Khalid, Farah F.; Deptuch, Grzegorz; Shenai, Alpana; Yarema, Raymond J.; /Fermilab

2010-11-01

Monolithic Active Matrix with Binary Counters (MAMBO) is a counting ASIC designed for detecting and measuring low energy X-rays from 6-12 keV. Each pixel contains analogue functionality implemented with a charge preamplifier, CR-RC{sup 2} shaper and a baseline restorer. It also contains a window comparator which can be trimmed by 4 bit DACs to remove systematic offsets. The hits are registered by a 12 bit ripple counter which is reconfigured as a shift register to serially output the data from the entire ASIC. Each pixel can be tested individually. Two diverse approaches have been used to prevent coupling between the detector and electronics in MAMBO III and MAMBO IV. MAMBO III is a 3D ASIC, the bottom ASIC consists of diodes which are connected to the top ASIC using {mu}-bump bonds. The detector is decoupled from the electronics by physically separating them on two tiers and using several metal layers as a shield. MAMBO IV is a monolithic structure which uses a nested well approach to isolate the detector from the electronics. The ASICs are being fabricated using the SOI 0.2 {micro}m OKI process, MAMBO III is 3D bonded at T-Micro and MAMBO IV nested well structure was developed in collaboration between OKI and Fermilab.

Endocytosis of collagen by hepatic stellate cells regulates extracellular matrix dynamics.

Science.gov (United States)

Bi, Yan; Mukhopadhyay, Dhriti; Drinane, Mary; Ji, Baoan; Li, Xing; Cao, Sheng; Shah, Vijay H

2014-10-01

Hepatic stellate cells (HSCs) generate matrix, which in turn may also regulate HSCs function during liver fibrosis. We hypothesized that HSCs may endocytose matrix proteins to sense and respond to changes in microenvironment. Primary human HSCs, LX2, or mouse embryonic fibroblasts (MEFs) [wild-type; c-abl(-/-); or Yes, Src, and Fyn knockout mice (YSF(-/-))] were incubated with fluorescent-labeled collagen or gelatin. Fluorescence-activated cell sorting analysis and confocal microscopy were used for measuring cellular internalization of matrix proteins. Targeted PCR array and quantitative real-time PCR were used to evaluate gene expression changes. HSCs and LX2 cells endocytose collagens in a concentration- and time-dependent manner. Endocytosed collagen colocalized with Dextran 10K, a marker of macropinocytosis, and 5-ethylisopropyl amiloride, an inhibitor of macropinocytosis, reduced collagen internalization by 46%. Cytochalasin D and ML7 blocked collagen internalization by 47% and 45%, respectively, indicating that actin and myosin are critical for collagen endocytosis. Wortmannin and AKT inhibitor blocked collagen internalization by 70% and 89%, respectively, indicating that matrix macropinocytosis requires phosphoinositide-3-kinase (PI3K)/AKT signaling. Overexpression of dominant-negative dynamin-2 K44A blocked matrix internalization by 77%, indicating a role for dynamin-2 in matrix macropinocytosis. Whereas c-abl(-/-) MEF showed impaired matrix endocytosis, YSF(-/-) MEF surprisingly showed increased matrix endocytosis. It was also associated with complex gene regulations that related with matrix dynamics, including increased matrix metalloproteinase 9 (MMP-9) mRNA levels and zymographic activity. HSCs endocytose matrix proteins through macropinocytosis that requires a signaling network composed of PI3K/AKT, dynamin-2, and c-abl. Interaction with extracellular matrix regulates matrix dynamics through modulating multiple gene expressions including MMP-9

Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

Science.gov (United States)

Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert

2016-01-12

A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.

Matrix metalloproteinases in lung biology

Directory of Open Access Journals (Sweden)

Parks William C

2000-12-01

Full Text Available Abstract Despite much information on their catalytic properties and gene regulation, we actually know very little of what matrix metalloproteinases (MMPs do in tissues. The catalytic activity of these enzymes has been implicated to function in normal lung biology by participating in branching morphogenesis, homeostasis, and repair, among other events. Overexpression of MMPs, however, has also been blamed for much of the tissue destruction associated with lung inflammation and disease. Beyond their role in the turnover and degradation of extracellular matrix proteins, MMPs also process, activate, and deactivate a variety of soluble factors, and seldom is it readily apparent by presence alone if a specific proteinase in an inflammatory setting is contributing to a reparative or disease process. An important goal of MMP research will be to identify the actual substrates upon which specific enzymes act. This information, in turn, will lead to a clearer understanding of how these extracellular proteinases function in lung development, repair, and disease.

Beneficial Regulation of Matrix Metalloproteinases for Skin Health

Directory of Open Access Journals (Sweden)

Neena Philips

2011-01-01

Full Text Available Matrix metalloproteinases (MMPs are essential to the remodeling of the extracellular matrix. While their upregulation facilitates aging and cancer, they are essential to epidermal differentiation and the prevention of wound scars. The pharmaceutical industry is active in identifying products that inhibit MMPs to prevent or treat aging and cancer and products that stimulate MMPs to prevent epidermal hyperproliferative diseases and wound scars.

Leflunomide and methotrexate reduce levels of activated matrix metalloproteinases in complexes with α2 macroglobulin in serum of rheumatoid arthritis patients

NARCIS (Netherlands)

Tchetverikov, I.; Kraan, M.C.; El, B. van; Hanemaaijer, R.; Groot, J. de; Huizinga, T.W.J.

2008-01-01

Objective: To analyse the effects of leflunomide and methotrexate treatment on matrix metalloproteinase (MMP) activity levels in a2 macroglobulin/MMP (α2M/MMP) complexes in the systemic circulation of rheumatoid arthritis (RA) patients. Methods: A total of 102 RA patients from a prospective,

1.54 μm Er3+ electroluminescence from an erbium-compound-doped organic light emitting diode with a p-type silicon anode

International Nuclear Information System (INIS)

Zhao, W Q; Wang, P F; Ran, G Z; Ma, G L; Zhang, B R; Liu, W M; Wu, S K; Dai, L; Qin, G G

2006-01-01

By doping an erbium complex, erbium (III) 2, 4-pentanedionate (Er(acac) 3 ), into the ALQ layer, we fabricate a series of infrared emission organic light emitting diodes (OLED) with structures of p-Si/SiO 2 /NPB/ALQ/ ALQ:Er(acac) 3 /ALQ/Sm/Au, where p-Si is the anode and Sm/Au is the cathode. The 1.54 μm emission from Er 3+ is observed. The impact of doping level of Er(acac) 3 in ALQ on 1.54 μm electroluminescence (EL) intensity is studied, and the best mass ratio of Er(acac) 3 to ALQ is found at 1:60. A competitive EL mechanism from the ALQ and Er(acac) 3 is found and the Er 3+ ions excitations are attributed to energy transfer from the ligands to Er ions

Control of extracellular matrix assembly by syndecan-2 proteoglycan

DEFF Research Database (Denmark)

Klass, C M; Couchman, J R; Woods, A

2000-01-01

Extracellular matrix (ECM) deposition and organization is maintained by transmembrane signaling and integrins play major roles. We now show that a second transmembrane component, syndecan-2 heparan sulfate proteoglycan, is pivotal in matrix assembly. Chinese Hamster Ovary (CHO) cells were stably...... to rearrange laminin or fibronectin substrates into fibrils and to bind exogenous fibronectin. Transfection of activated alphaIIbalphaLdeltabeta3 integrin into alpha(5)-deficient CHO B2 cells resulted in reestablishment of the previously lost fibronectin matrix. However, cotransfection of this cell line with S...

The provisional matrix: setting the stage for tissue repair outcomes.

Science.gov (United States)

Barker, Thomas H; Engler, Adam J

2017-07-01

Since its conceptualization in the 1980s, the provisional matrix has often been characterized as a simple fibrin-containing scaffold for wound healing that supports the nascent blood clot and is functionally distinct from the basement membrane. However subsequent advances have shown that this matrix is far from passive, with distinct compositional differences as the wound matures, and providing an active role for wound remodeling. Here we review the stages of this matrix, provide an update on the state of our understanding of provisional matrix, and present some of the outstanding issues related to the provisional matrix, its components, and their assembly and use in vivo. Copyright © 2017. Published by Elsevier B.V.

Prospective Effects of Statin in Repression of Matrix Metalloproteinases Activities in Irradiated Rats

International Nuclear Information System (INIS)

Zahran, A.M.; Sallam, M.H.

2009-01-01

Several studies had been committed that HMG-CoA (3-Hydroxy-3 methylglutaryl coenzyme A) reductase inhibitors (statins) may exert a pleotropic effects attributed to mechanisms independent of their conventional hypolipidaemic effects. Meantime, inadequate studies have been sustained these independence mechanisms in regard to regulation and signal transduction of matrix metalloproteinases (MMPs). Sprague Dawley male albino rats were given by gavage atorvastatin; a synthetic form of statins, at a dose of I mg/kg body weight/day for 7 successive days before starting irradiation and 15 successive days during and along the exposure to γ-radiation. Rats were exposed to fractionated whole body gamma radiation, delivered as 1 Gy every other day up to total dose of 8 Gy. Quantitative assay of gelatinolytic zymographic analysis of serum and hepatic tissues showed that exposure to γ rays yields a marked significant increase in the activities of both pro-MMP-9 and active MMP-9 (92 and 86 kDa), as well as pro-MMP-2 and active MMP-2 (72 and 66 kDa), respectively. Administration of atorvastatin has significantly lowered the MMP-2 and MMP-9 enzymatic activity in y-irradiated rats, Conclusion: the present study demonstrated that irradiation of rats led to up regulation of enzymatic activities of MMP-2 and MMP-9 in their pro- and active forms. Administration of atorvastatin exerted defensive effects on γ irradiated rats via down regulation of MMP-2 and MMP-9. Moreover, atorvastatin may be applied to minimize radiation-induced oxidative damage and attenuate the side effects of radiotherapy. However, these results observed in rats need to be confirmed in other experimental models

Prospective Effects of Statin in Repression of Matrix Metalloproteinases Activities in Irradiated Rats

International Nuclear Information System (INIS)

Zahran, A.M.; Sallam, M.H.

2008-01-01

Several studies had been committed that HMG-CoA (3-Hydroxy-3 methylglutaryl coenzyme A) reductase inhibitors (statins) may exert a pleotropic effects attributed to mechanisms independent of their conventional hypolipidaemic effects. Meantime, inadequate studies have been sustained these independence mechanisms in regard to regulation and signal transduction of matrix metalloproteinases (MMPs). Sprague Dawley male albino rats were given by gavage atorvastatin; a synthetic form of statins, at a dose of I mg/kg body weight/day for 7 successive days before starting irradiation and 15 successive days during and along the exposure to γ-radiation. Rats were exposed to fractionated whole body gamma radiation, delivered as 1 Gy every other day up to total dose of 8 Gy. Quantitative assay of gelatinolytic zymographic analysis of serum and hepatic tissues showed that exposure to γ rays yields a marked significant increase in the activities of both pro-MMP-9 and active MMP-9 (92 and 86 kDa), as well as pro-MMP-2 and active MMP-2 (72 and 66 kDa), respectively. Administration of atorvastatin has significantly lowered the MMP-2 and MMP-9 enzymatic activity in y-irradiated rats, Conclusion: the present study demonstrated that irradiation of rats led to up regulation of enzymatic activities of MMP-2 and MMP-9 in their pro- and active forms. Administration of atorvastatin exerted defensive effects on γ irradiated rats via down regulation of MMP-2 and MMP-9. Moreover, atorvastatin may be applied to minimize radiation-induced oxidative damage and attenuate the side effects of radiotherapy. However, these results observed in rats need to be confirmed in other experimental models

Prospective Effects of Statin in Repression of Matrix Metalloproteinases Activities in Irradiated Rats

Energy Technology Data Exchange (ETDEWEB)

Zahran, A M [Radiation Biology Department, National Centre/or Radiation Research and Technology (NCRRT), Atomic Energy Authority, Cairo (Egypt); Sallam, M H [Health Radiation Research Department, Radiation Research and Technology (NCRRT), Atomic Energy Authority, Cairo (Egypt)

2008-07-01

Several studies had been committed that HMG-CoA (3-Hydroxy-3 methylglutaryl coenzyme A) reductase inhibitors (statins) may exert a pleotropic effects attributed to mechanisms independent of their conventional hypolipidaemic effects. Meantime, inadequate studies have been sustained these independence mechanisms in regard to regulation and signal transduction of matrix metalloproteinases (MMPs). Sprague Dawley male albino rats were given by gavage atorvastatin; a synthetic form of statins, at a dose of I mg/kg body weight/day for 7 successive days before starting irradiation and 15 successive days during and along the exposure to {gamma}-radiation. Rats were exposed to fractionated whole body gamma radiation, delivered as 1 Gy every other day up to total dose of 8 Gy. Quantitative assay of gelatinolytic zymographic analysis of serum and hepatic tissues showed that exposure to {gamma} rays yields a marked significant increase in the activities of both pro-MMP-9 and active MMP-9 (92 and 86 kDa), as well as pro-MMP-2 and active MMP-2 (72 and 66 kDa), respectively. Administration of atorvastatin has significantly lowered the MMP-2 and MMP-9 enzymatic activity in y-irradiated rats, Conclusion: the present study demonstrated that irradiation of rats led to up regulation of enzymatic activities of MMP-2 and MMP-9 in their pro- and active forms. Administration of atorvastatin exerted defensive effects on {gamma} irradiated rats via down regulation of MMP-2 and MMP-9. Moreover, atorvastatin may be applied to minimize radiation-induced oxidative damage and attenuate the side effects of radiotherapy. However, these results observed in rats need to be confirmed in other experimental models.

Prospective Effects of Statin in Repression of Matrix Metalloproteinases Activities in Irradiated Rats

Energy Technology Data Exchange (ETDEWEB)

Zahran, A M [Radiation Biology Department, National Centre/or Radiation Research and Technology (NCRRT), Atomic Energy Authority, Cairo (Egypt); Sallam, M H [Health Radiation Research Department, Radiation Research and Technology (NCRRT), Atomic Energy Authority, Cairo (Egypt)

2009-07-01

Several studies had been committed that HMG-CoA (3-Hydroxy-3 methylglutaryl coenzyme A) reductase inhibitors (statins) may exert a pleotropic effects attributed to mechanisms independent of their conventional hypolipidaemic effects. Meantime, inadequate studies have been sustained these independence mechanisms in regard to regulation and signal transduction of matrix metalloproteinases (MMPs). Sprague Dawley male albino rats were given by gavage atorvastatin; a synthetic form of statins, at a dose of I mg/kg body weight/day for 7 successive days before starting irradiation and 15 successive days during and along the exposure to {gamma}-radiation. Rats were exposed to fractionated whole body gamma radiation, delivered as 1 Gy every other day up to total dose of 8 Gy. Quantitative assay of gelatinolytic zymographic analysis of serum and hepatic tissues showed that exposure to {gamma} rays yields a marked significant increase in the activities of both pro-MMP-9 and active MMP-9 (92 and 86 kDa), as well as pro-MMP-2 and active MMP-2 (72 and 66 kDa), respectively. Administration of atorvastatin has significantly lowered the MMP-2 and MMP-9 enzymatic activity in y-irradiated rats, Conclusion: the present study demonstrated that irradiation of rats led to up regulation of enzymatic activities of MMP-2 and MMP-9 in their pro- and active forms. Administration of atorvastatin exerted defensive effects on {gamma} irradiated rats via down regulation of MMP-2 and MMP-9. Moreover, atorvastatin may be applied to minimize radiation-induced oxidative damage and attenuate the side effects of radiotherapy. However, these results observed in rats need to be confirmed in other experimental models.

Observation of near infrared and enhanced visible emissions from electroluminescent devices with organo samarium(III) complex

Energy Technology Data Exchange (ETDEWEB)

Chu, B [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Li, W L [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Hong, Z R [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Zang, F X [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Wei, H Z [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Wang, D Y [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Li, M T [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dong NanHu Road, Economic Development Area, Changchun, 130033 (China); Lee, C S [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China); Lee, S T [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China)

2006-11-07

Samarium (dibenzoylmethanato){sub 3} bathophenanthroline (Sm(DBM){sub 3} bath) was employed as an emitting and electron transport layer in organic light emitting diodes (OLEDs), and narrow electroluminescent (EL) emissions of a Sm{sup 3+} ion were observed in the visible and near infrared (NIR) region, differing from those of the same devices with Eu{sup 3+}- or Tb{sup 3+}-complex EL devices with the same structure. The EL emissions of the Sm{sup 3+}-devices originate from transitions from {sup 4}G{sub 5/2} to the lower respective levels of Sm{sup 3+} ions. A maximum luminance of 490 cd m{sup -2} at 15 V and an EL efficiency of 0.6% at 0.17 mA cm{sup -2} were obtained in the visible region, and the improved efficiency should be attributed to introducing a transitional layer between the N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) film and the Sm(DBM){sub 3} bath film and the avoidance of interfacial exciplex emission in devices. Sharp emissions of Sm{sup 3+} ions in the NIR region were also observed under a lower threshold value less than 4.5 V.

Red Grape Skin Polyphenols Blunt Matrix Metalloproteinase-2 and -9 Activity and Expression in Cell Models of Vascular Inflammation: Protective Role in Degenerative and Inflammatory Diseases

Directory of Open Access Journals (Sweden)

Nadia Calabriso

2016-08-01

Full Text Available Matrix metalloproteinases (MMPs are endopeptidases responsible for the hydrolysis of various components of extracellular matrix. MMPs, namely gelatinases MMP-2 and MMP-9, contribute to the progression of chronic and degenerative diseases. Since gelatinases’ activity and expression are regulated by oxidative stress, we sought to evaluate whether supplementation with polyphenol-rich red grape skin extracts modulated the matrix-degrading capacity in cell models of vascular inflammation. Human endothelial and monocytic cells were incubated with increasing concentrations (0.5–25 μg/mL of Negroamaro and Primitivo red grape skin polyphenolic extracts (NSPE and PSPE, respectively or their specific components (0.5–25 μmol/L, before stimulation with inflammatory challenge. NSPE and PSPE inhibited, in a concentration-dependent manner, endothelial invasion as well as the MMP-9 and MMP-2 release in stimulated endothelial cells, and MMP-9 production in inflamed monocytes, without affecting tissue inhibitor of metalloproteinases (TIMP-1 and TIMP-2. The matrix degrading inhibitory capacity was the same for both NSPE and PSPE, despite their different polyphenolic profiles. Among the main polyphenols of grape skin extracts, trans-resveratrol, trans-piceid, kaempferol and quercetin exhibited the most significant inhibitory effects on matrix-degrading enzyme activities. Our findings appreciate the grape skins as rich source of polyphenols able to prevent the dysregulation of vascular remodelling affecting degenerative and inflammatory diseases.

Fibroblasts and the extracellular matrix in right ventricular disease.

Science.gov (United States)

Frangogiannis, Nikolaos G

2017-10-01

Right ventricular failure predicts adverse outcome in patients with pulmonary hypertension (PH), and in subjects with left ventricular heart failure and is associated with interstitial fibrosis. This review manuscript discusses the cellular effectors and molecular mechanisms implicated in right ventricular fibrosis. The right ventricular interstitium contains vascular cells, fibroblasts, and immune cells, enmeshed in a collagen-based matrix. Right ventricular pressure overload in PH is associated with the expansion of the fibroblast population, myofibroblast activation, and secretion of extracellular matrix proteins. Mechanosensitive transduction of adrenergic signalling and stimulation of the renin-angiotensin-aldosterone cascade trigger the activation of right ventricular fibroblasts. Inflammatory cytokines and chemokines may contribute to expansion and activation of macrophages that may serve as a source of fibrogenic growth factors, such as transforming growth factor (TGF)-β. Endothelin-1, TGF-βs, and matricellular proteins co-operate to activate cardiac myofibroblasts, and promote synthesis of matrix proteins. In comparison with the left ventricle, the RV tolerates well volume overload and ischemia; whether the right ventricular interstitial cells and matrix are implicated in these favourable responses remains unknown. Expansion of fibroblasts and extracellular matrix protein deposition are prominent features of arrhythmogenic right ventricular cardiomyopathies and may be implicated in the pathogenesis of arrhythmic events. Prevailing conceptual paradigms on right ventricular remodelling are based on extrapolation of findings in models of left ventricular injury. Considering the unique embryologic, morphological, and physiologic properties of the RV and the clinical significance of right ventricular failure, there is a need further to dissect RV-specific mechanisms of fibrosis and interstitial remodelling. Published on behalf of the European Society of

CAPN 7 promotes the migration and invasion of human endometrial stromal cell by regulating matrix metalloproteinase 2 activity.

Science.gov (United States)

Liu, Hongyu; Jiang, Yue; Jin, Xiaoyan; Zhu, Lihua; Shen, Xiaoyue; Zhang, Qun; Wang, Bin; Wang, Junxia; Hu, Yali; Yan, Guijun; Sun, Haixiang

2013-07-15

Matrix metalloproteinase 2 (MMP-2) has been reported to be an important regulator of cell migration and invasion through degradation of the extracellular matrix (ECM) in many diseases, such as cancer and endometriosis. Here, we found calcium-activated neutral protease 7 (CAPN 7) expression was markedly upregulated in the eutopic endometrium and endometrial stromal cells of women diagnosed with endometriosis. Our studies were carried out to detect the effects of CAPN 7 on human endometrial stromal cell (hESC) migration and invasion. Western blotting and quantitative real-time PCR were used to detect the expression of CAPN 7 in endometriosis patients and normal fertile women. Scratch-wound-healing and invasion chamber assay were used to investigate the role of CAPN 7 in hESC migration and invasion. Western blotting, quantitative real-time PCR and zymography were carried out to detect the effect of CAPN 7 on the expressions and activity of MMP-2. CAPN 7 was markedly up-regulated in endometriosis, thereby promoting the migration and invasion of hESC. CAPN 7 overexpression led to increased expression of MMP-2 and tissue inhibitor of metalloproteinases 2 (TIMP-2); CAPN 7 knockdown reversed these changes. CAPN 7 increased MMP-2 activity by increasing the ratio of MMP-2 to TIMP-2. We also found that OA-Hy (an MMP-2 inhibitor) decreased the effects of CAPN 7 overexpression on hESC migration and invasion by approximately 50% and 55%, respectively. Additionally, a coimmunoprecipitation assay demonstrated that CAPN 7 interacted with activator protein 2α (AP-2α): an important transcription factor of MMP-2. CAPN 7 promotes hESC migration and invasion by increasing the activity of MMP-2 via an increased ratio of MMP-2 to TIMP-2.

The effect of chronic periodontitis on serum levels of matrix ...

African Journals Online (AJOL)

A complex network of chemokines and pro- and anti-inflammatory mediators is involved in the initiation and progression of chronic periodontitis. Matrix metalloproteinases (MMPs), the main enzymes responsible for matrix degradation, are important for periodontal tissue destruction, but their activity can be inhibited by tissue ...

Plastic substrates for active matrix liquid crystal display incapable of withstanding processing temperature of over 200 C and method of fabrication

Energy Technology Data Exchange (ETDEWEB)

Carey, P.G.; Smith, P.M.; Havens, J.H.; Jones, P.

1999-01-05

Bright-polarizer-free, active-matrix liquid crystal displays (AMLCDs) are formed on plastic substrates. The primary components of the display are a pixel circuit fabricated on one plastic substrate, an intervening liquid-crystal material, and a counter electrode on a second plastic substrate. The-pixel circuit contains one or more thin-film transistors (TFTs) and either a transparent or reflective pixel electrode manufactured at sufficiently low temperatures to avoid damage to the plastic substrate. Fabrication of the TFTs can be carried out at temperatures less than 100 C. The liquid crystal material is a commercially made nematic curvilinear aligned phase (NCAP) film. The counter electrode is comprised of a plastic substrate coated with a transparent conductor, such as indium-doped tin oxide (ITO). By coupling the active matrix with NCAP, a high-information content can be provided in a bright, fully plastic package. Applications include any low cost portable electronics containing flat displays where ruggedization of the display is desired. 12 figs.

Production of active lysozyme films by matrix assisted pulsed laser evaporation at 355 nm

DEFF Research Database (Denmark)

Purice, Andreea; Schou, Jørgen; Kingshott, P.

2007-01-01

Thin lysozyme films have been produced in a dry environment by MAPLE (matrix assisted pulsed laser evaporation) from a water ice matrix irradiated by laser light at 355 nm above the absorption threshold of the protein. A significant part of the lysozyme molecules are transferred to the film without...

Periodontal Disease, Matrix Metalloproteinases and Chemically Modified Tetracyclines

OpenAIRE

Steinsvoll, Svein

2011-01-01

Matrix metalloproteinases (MMPs) are crucial in the degradation of the main components in the extracellular matrix and thereby play important roles in cell migration, wound healing and tissue remodelling. MMPs have pathogenic roles in arthritis, periodontitis, hepatitis, glomerulonephritis, atherosclerosis and cancer cell invasion. MMPs are activators of pro-inflammatory mediators that occur in latent forms, such as interleukin (IL)-1β, membrane-bound tumour necrosis factor (TNF) and dif...

Ceramic matrix and resin matrix composites - A comparison

Science.gov (United States)

Hurwitz, Frances I.

1987-01-01

The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.

Ceramic matrix and resin matrix composites: A comparison

Science.gov (United States)

Hurwitz, Frances I.

1987-01-01

The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.

In vivo imaging of extracellular matrix remodeling by tumor-associated fibroblasts

DEFF Research Database (Denmark)

Perentes, Jean Y; McKee, Trevor D; Ley, Carsten D

2009-01-01

Here we integrated multiphoton laser scanning microscopy and the registration of second harmonic generation images of collagen fibers to overcome difficulties in tracking stromal cell-matrix interactions for several days in live mice. We show that the matrix-modifying hormone relaxin increased...... tumor-associated fibroblast (TAF) interaction with collagen fibers by stimulating beta1-integrin activity, which is necessary for fiber remodeling by matrix metalloproteinases....

Matrix Management Structures in Higher Education. Coombe Lodge Working Paper. Information Bank Number 1394.

Science.gov (United States)

Cuthbert, Rob

The matrix structure as an alternative to the departmental structure for colleges and universities is discussed, and the matrix system at Middlesex Polytechnic in England is used as illustration. The major impact of the introduction of a matrix structure is its effect on teaching activities within the institution. The matrix structure formally…

Enhanced activation of matrix metalloproteinase-9 correlates with the degree of papillary thyroid carcinoma infiltration

Science.gov (United States)

Marečko, Ilona; Cvejić, Dubravka; Šelemetjev, Sonja; Paskaš, Svetlana; Tatić, Svetislav; Paunović, Ivan; Savin, Svetlana

2014-01-01

Aim To determine whether matrix metalloproteinase-9 (MMP-9) may be a useful adjunctive tool for predicting unfavorable biological behavior of papillary thyroid carcinoma (PTC) by evaluating the expression profile and proteolytic activity of MMP-9 in PTC by different techniques and correlating the findings with clinicopathological prognostic factors. Methods Immunohistochemical localization of MMP-9 was analyzed with antibodies specific for either total or active MMP-9. Activation ratios of MMP-9 were calculated by quantifying gel zymography bands. Enzymatic activity of MMP-9 was localized by in situ zymography after inhibiting MMP-2 activity. Results Immunostaining of total and active MMP-9 was observed in tumor tissue and occasionally in non-neoplastic epithelium. Only active MMP-9 was significantly associated with extrathyroid invasion, lymph-node metastasis, and the degree of tumor infiltration (P zymography revealed a correlation between the MMP-9 activation ratio and nodal involvement, extrathyroid invasion, and the degree of tumor infiltration. In situ zymography showed that gelatinases exerted their activity in tumor parenchymal and stromal cells. Moreover, after application of MMP-2 inhibitor, the remaining gelatinase activity, corresponding to MMP-9, was highest in cancers with the most advanced degree of tumor infiltration. Conclusions This is the first report suggesting that the evaluation of active MMP-9 by immunohistochemistry and determination of its activation ratio by gelatin zymography may be a useful adjunct to the known clinicopathological factors in predicting tumor behavior. Most important, in situ zimography with an MMP-2 inhibitor for the first time demonstrated a strong impact of MMP-9 activity on the degree of tumor infiltration during PTC progression. PMID:24778099

Study of narrow and intense UV electroluminescence from ITO/SRO/Si-p and ITO/SRN/SRO/Si-p based light emitting capacitors

International Nuclear Information System (INIS)

Cabañas-Tay, S.A.; Palacios-Huerta, L.; Aceves-Mijares, M.; Coyopol, A.; Morales-Morales, F.; Pérez-García, S.A.; Licea-Jiménez, L.; Domínguez-Horna, C.; Monfil-Leyva, K.; Morales-Sánchez, A.

2017-01-01

In this work, multiple narrow and highly intense ultraviolet (UV) electroluminescent (EL) bands were observed in light emitting capacitors (LECs) using silicon rich oxide (SRO) films as active layer. Besides, the effect of a thin silicon rich nitride (SRN) film on top of the SRO (as SRN/SRO bilayer) layer was also studied. LECs were fabricated using simple metal–insulator–semiconductor (MIS) structures with indium tin oxide (ITO) and aluminum as gate and substrate electrodes, respectively. SRO and SRN films contain 41.85±1.1 and 46.96±1.1 at% of silicon, respectively. Both structures exhibited a resistance switching (RS) behavior from a high conduction state (HCS) to a low conduction state (LCS), enhancing an intense UV EL. This RS behavior produces structural changes in the active layer and probably in the ITO contact. Seven narrow bands with half-peak width of 7±0.6 nm at ~250, 270, 285, 305, 325, 415 and 450 nm were clearly observed once the LCS was reached. These bands could be related to a combination of emissions through defects inside SRO (252, 288.2 and 415 nm), and characteristic radiation of neutral tin (252.39 and 286.33 nm), neutral indium (271.02, 303.93 and 325.85 nm), single (444.82 nm) and doubly ionized indium (403.07 nm). Furthermore, red EL was observed at the HCS and it was similar to the PL spectra indicating the same radiative process involved. The charge transport is improved when the SRN/SRO bilayer is used as active layer in the LEC. An EL band at ~590 nm is observed when the SRN/SRO bilayer is formed at both conduction states. This band has been observed before and attributed to transitions from the minimum conduction band to K° centers in SRN films. The conduction mechanism responsible of the EL at both conduction states was also studied.

Study of narrow and intense UV electroluminescence from ITO/SRO/Si-p and ITO/SRN/SRO/Si-p based light emitting capacitors

Energy Technology Data Exchange (ETDEWEB)

Cabañas-Tay, S.A., E-mail: scabanastay@hotmail.com [Centro de Investigación en Materiales Avanzados S.C., Unidad Monterrey-PIIT, 66600, Apodaca, Nuevo León (Mexico); Palacios-Huerta, L.; Aceves-Mijares, M. [INAOE, Electronics Department, Apartado 51, Puebla 72000 (Mexico); Coyopol, A. [CIDS-BUAP, Apdo. 1651, Puebla Pue 72000 (Mexico); Morales-Morales, F.; Pérez-García, S.A.; Licea-Jiménez, L. [Centro de Investigación en Materiales Avanzados S.C., Unidad Monterrey-PIIT, 66600, Apodaca, Nuevo León (Mexico); Domínguez-Horna, C. [Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Bellaterra, 08103, Barcelona (Spain); Monfil-Leyva, K. [CIDS-BUAP, Apdo. 1651, Puebla Pue 72000 (Mexico); Morales-Sánchez, A., E-mail: alfredo.morales@cimav.edu.mx [Centro de Investigación en Materiales Avanzados S.C., Unidad Monterrey-PIIT, 66600, Apodaca, Nuevo León (Mexico)

2017-03-15

In this work, multiple narrow and highly intense ultraviolet (UV) electroluminescent (EL) bands were observed in light emitting capacitors (LECs) using silicon rich oxide (SRO) films as active layer. Besides, the effect of a thin silicon rich nitride (SRN) film on top of the SRO (as SRN/SRO bilayer) layer was also studied. LECs were fabricated using simple metal–insulator–semiconductor (MIS) structures with indium tin oxide (ITO) and aluminum as gate and substrate electrodes, respectively. SRO and SRN films contain 41.85±1.1 and 46.96±1.1 at% of silicon, respectively. Both structures exhibited a resistance switching (RS) behavior from a high conduction state (HCS) to a low conduction state (LCS), enhancing an intense UV EL. This RS behavior produces structural changes in the active layer and probably in the ITO contact. Seven narrow bands with half-peak width of 7±0.6 nm at ~250, 270, 285, 305, 325, 415 and 450 nm were clearly observed once the LCS was reached. These bands could be related to a combination of emissions through defects inside SRO (252, 288.2 and 415 nm), and characteristic radiation of neutral tin (252.39 and 286.33 nm), neutral indium (271.02, 303.93 and 325.85 nm), single (444.82 nm) and doubly ionized indium (403.07 nm). Furthermore, red EL was observed at the HCS and it was similar to the PL spectra indicating the same radiative process involved. The charge transport is improved when the SRN/SRO bilayer is used as active layer in the LEC. An EL band at ~590 nm is observed when the SRN/SRO bilayer is formed at both conduction states. This band has been observed before and attributed to transitions from the minimum conduction band to K° centers in SRN films. The conduction mechanism responsible of the EL at both conduction states was also studied.

AMP-activated protein kinase activation mediates CCL3-induced cell migration and matrix metalloproteinase-2 expression in human chondrosarcoma

Science.gov (United States)

2013-01-01

Chemokine (C-C motif) ligand 3 (CCL3), also known as macrophage inflammatory protein-1α, is a cytokine involved in inflammation and activation of polymorphonuclear leukocytes. CCL3 has been detected in infiltrating cells and tumor cells. Chondrosarcoma is a highly malignant tumor that causes distant metastasis. However, the effect of CCL3 on human chondrosarcoma metastasis is still unknown. Here, we found that CCL3 increased cellular migration and expression of matrix metalloproteinase (MMP)-2 in human chondrosarcoma cells. Pre-treatment of cells with the MMP-2 inhibitor or transfection with MMP-2 specific siRNA abolished CCL3-induced cell migration. CCL3 has been reported to exert its effects through activation of its specific receptor, CC chemokine receptor 5 (CCR5). The CCR5 and AMP-activated protein kinase (AMPK) inhibitor or siRNA also attenuated CCL3-upregulated cell motility and MMP-2 expression. CCL3-induced expression of MMP-2 and migration were also inhibited by specific inhibitors, and inactive mutants of AMPK, p38 mitogen activated protein kinase (p38 or p38-MAPK), and nuclear factor κB (NF-κB) cascades. On the other hand, CCL3 treatment demonstrably activated AMPK, p38, and NF-κB signaling pathways. Furthermore, the expression levels of CCL3, CCR5, and MMP-2 were correlated in human chondrosarcoma specimens. Taken together, our results indicate that CCL3 enhances the migratory ability of human chondrosarcoma cells by increasing MMP-2 expression via the CCR5, AMPK, p38, and NF-κB pathways. PMID:24047437

Extended biorthogonal matrix polynomials

Directory of Open Access Journals (Sweden)

Ayman Shehata

2017-01-01

Full Text Available The pair of biorthogonal matrix polynomials for commutative matrices were first introduced by Varma and Tasdelen in [22]. The main aim of this paper is to extend the properties of the pair of biorthogonal matrix polynomials of Varma and Tasdelen and certain generating matrix functions, finite series, some matrix recurrence relations, several important properties of matrix differential recurrence relations, biorthogonality relations and matrix differential equation for the pair of biorthogonal matrix polynomials J(A,B n (x, k and K(A,B n (x, k are discussed. For the matrix polynomials J(A,B n (x, k, various families of bilinear and bilateral generating matrix functions are constructed in the sequel.

TECHNOLOGY AND ANALYSIS DEVELOPMENT OF STOMATOLOGICAL MATRIX SYSTEM OF MULTIFUNCTIONAL ACTION DELIVERY

Directory of Open Access Journals (Sweden)

T. F. Marinina

2014-01-01

Full Text Available Timeliness of double-layer matrix system (of stomatological medicated films with antiinflammatory, local anesthetic, regenerative, anti-edematous action was shown. One layer of the system includes lidocaine hydrochloride and kalanchoe sap, another contains furacilin and urea. The best possible polymer carriers of preparations under study which provide their sufficient release from matrix system. Signified antimicrobic activity of double-layer system and osmotic activity were established. Double-layer matrix systems offered may be used in stomatology with for treatment and preventive measures of different diseases of parodontium tissues

Exogenous L-arginine reduces matrix metalloproteinase-2 and -9 activities and oxidative stress in patients with hypertension

DEFF Research Database (Denmark)

Garcia, Vinicius P; Rocha, Helena N M; Silva, Gustavo M.

2016-01-01

Aims Increased matrix metalloproteinases activity and reduced nitric oxide (NO) bioavailability contributes to development of hypertension and this may be associated with a defective L-arginine-NO pathway. Exogenous L-arginine improves endothelial function to prevent the onset of cardiovascular...... disease, but the mechanism by which this is accomplished remains unclear. We determined the effects of exogenous L-arginine infusion on vascular biomarkers in patients with hypertension. Main methods Venous blood samples were obtained from seven patients with hypertension (45 ± 5 yrs., HT group...... biomarkers between groups during the saline infusion (P > 0.05). Significance Exogenous L-arginine diminished metalloproteinase-2 and -9 activities and MMP-9/TIMP-1 ratio along with restoring the oxidative stress balance in patients with hypertension....

Cytokine Response to Diet and Exercise Affects Atheromatous Matrix Metalloproteinase-2/9 Activity in Mice.

Science.gov (United States)

Shon, Soo-Min; Jang, Hee Jeong; Schellingerhout, Dawid; Kim, Jeong-Yeon; Ryu, Wi-Sun; Lee, Su-Kyoung; Kim, Jiwon; Park, Jin-Yong; Oh, Ji Hye; Kang, Jeong Wook; Je, Kang-Hoon; Park, Jung E; Kim, Kwangmeyung; Kwon, Ick Chan; Lee, Juneyoung; Nahrendorf, Matthias; Park, Jong-Ho; Kim, Dong-Eog

2017-09-25

The aim of this study is to identify the principal circulating factors that modulate atheromatous matrix metalloproteinase (MMP) activity in response to diet and exercise.Methods and Results:Apolipoprotein-E knock-out (ApoE -/- ) mice (n=56) with pre-existing plaque, fed either a Western diet (WD) or normal diet (ND), underwent either 10 weeks of treadmill exercise or had no treatment. Atheromatous MMP activity was visualized using molecular imaging with a MMP-2/9 activatable near-infrared fluorescent (NIRF) probe. Exercise did not significantly reduce body weight, visceral fat, and plaque size in either WD-fed animals or ND-fed animals. However, atheromatous MMP-activity was different; ND animals that did or did not exercise had similarly low MMP activities, WD animals that did not exercise had high MMP activity, and WD animals that did exercise had reduced levels of MMP activity, close to the levels of ND animals. Factor analysis and path analysis showed that soluble vascular cell adhesion molecule (sVCAM)-1 was directly positively correlated to atheromatous MMP activity. Adiponectin was indirectly negatively related to atheromatous MMP activity by way of sVCAM-1. Resistin was indirectly positively related to atheromatous MMP activity by way of sVCAM-1. Visceral fat amount was indirectly positively associated with atheromatous MMP activity, by way of adiponectin reduction and resistin elevation. MMP-2/9 imaging of additional mice (n=18) supported the diet/exercise-related anti-atherosclerotic roles for sVCAM-1. Diet and exercise affect atheromatous MMP activity by modulating the systemic inflammatory milieu, with sVCAM-1, resistin, and adiponectin closely interacting with each other and with visceral fat.

M(atrix) theory: matrix quantum mechanics as a fundamental theory

International Nuclear Information System (INIS)

Taylor, Washington

2001-01-01

This article reviews the matrix model of M theory. M theory is an 11-dimensional quantum theory of gravity that is believed to underlie all superstring theories. M theory is currently the most plausible candidate for a theory of fundamental physics which reconciles gravity and quantum field theory in a realistic fashion. Evidence for M theory is still only circumstantial -- no complete background-independent formulation of the theory exists as yet. Matrix theory was first developed as a regularized theory of a supersymmetric quantum membrane. More recently, it has appeared in a different guise as the discrete light-cone quantization of M theory in flat space. These two approaches to matrix theory are described in detail and compared. It is shown that matrix theory is a well-defined quantum theory that reduces to a supersymmetric theory of gravity at low energies. Although its fundamental degrees of freedom are essentially pointlike, higher-dimensional fluctuating objects (branes) arise through the non-Abelian structure of the matrix degrees of freedom. The problem of formulating matrix theory in a general space-time background is discussed, and the connections between matrix theory and other related models are reviewed

Dimerization Efficiency of Canine Distemper Virus Matrix Protein Regulates Membrane-Budding Activity.

Science.gov (United States)

Bringolf, Fanny; Herren, Michael; Wyss, Marianne; Vidondo, Beatriz; Langedijk, Johannes P; Zurbriggen, Andreas; Plattet, Philippe

2017-08-15

Paramyxoviruses rely on the matrix (M) protein to orchestrate viral assembly and budding at the plasma membrane. Although the mechanistic details remain largely unknown, structural data suggested that M dimers and/or higher-order oligomers may facilitate membrane budding. To gain functional insights, we employed a structure-guided mutagenesis approach to investigate the role of canine distemper virus (CDV) M protein self-assembly in membrane-budding activity. Three six-alanine-block (6A-block) mutants with mutations located at strategic oligomeric positions were initially designed. While the first one includes residues potentially residing at the protomer-protomer interface, the other two display amino acids located within two distal surface-exposed α-helices proposed to be involved in dimer-dimer contacts. We further focused on the core of the dimeric interface by mutating asparagine 138 (N138) to several nonconservative amino acids. Cellular localization combined with dimerization and coimmunopurification assays, performed under various denaturing conditions, revealed that all 6A-block mutants were impaired in self-assembly and cell periphery accumulation. These phenotypes correlated with deficiencies in relocating CDV nucleocapsid proteins to the cell periphery and in virus-like particle (VLP) production. Conversely, all M-N138 mutants remained capable of self-assembly, though to various extents, which correlated with proper accumulation and redistribution of nucleocapsid proteins at the plasma membrane. However, membrane deformation and VLP assays indicated that the M-N138 variants exhibiting the most reduced dimerization propensity were also defective in triggering membrane remodeling and budding, despite proper plasma membrane accumulation. Overall, our data provide mechanistic evidence that the efficiency of CDV M dimerization/oligomerization governs both cell periphery localization and membrane-budding activity. IMPORTANCE Despite the availability of

Interplay of Matrix Stiffness and c-SRC in Hepatic Fibrosis

DEFF Research Database (Denmark)

Görtzen, Jan; Schierwagen, Robert; Bierwolf, Jeanette

2015-01-01

. This study investigated the interaction of c-SRC and RhoA under different matrix stiffness conditions. METHODS: Liver fibrosis was induced in rats using bile duct ligation (BDL), thioacetamide (TAA) or carbon tetrachloride (CCl4) models. mRNA levels of albumin, PDGF-R, RHOA, COL1A1, and αSMA were analyzed......INTRODUCTION: In liver fibrosis activation of hepatic stellate cells (HSC) comprises phenotypical change into profibrotic and myofibroplastic cells with increased contraction and secretion of extracellular matrix (ECM) proteins. The small GTPase RhoA orchestrates cytoskeleton formation, migration......, and mobility via non-receptor tyrosine-protein kinase c-SRC (cellular sarcoma) in different cells. Furthermore, RhoA and its downstream effector Rho-kinase also play a crucial role in hepatic stellate cells and hepatic fibrogenesis. Matrix stiffness promotes HSC activation via cytoskeleton modulation...

Reduction of multipartite qubit density matrixes to bipartite qubit density matrixes and criteria of partial separability of multipartite qubit density matrixes

OpenAIRE

Zhong, Zai-Zhe

2004-01-01

The partial separability of multipartite qubit density matrixes is strictly defined. We give a reduction way from N-partite qubit density matrixes to bipartite qubit density matrixes, and prove a necessary condition that a N-partite qubit density matrix to be partially separable is its reduced density matrix to satisfy PPT condition.

Matrix metalloproteinases in acute coronary syndromes: current perspectives.

Science.gov (United States)

Kampoli, Anna-Maria; Tousoulis, Dimitris; Papageorgiou, Nikolaos; Antoniades, Charalambos; Androulakis, Emmanuel; Tsiamis, Eleftherios; Latsios, George; Stefanadis, Christodoulos

2012-01-01

Matrix metalloproteinases (MMPs) are a family of zinc metallo-endopeptidases secreted by cells and are responsible for much of the turnover of matrix components. Several studies have shown that MMPs are involved in all stages of the atherosclerotic process, from the initial lesion to plaque rupture. Recent evidence suggests that MMP activity may facilitate atherosclerosis, plaque destabilization, and platelet aggregation. In the heart, matrix metalloproteinases participate in vascular remodeling, plaque instability, and ventricular remodelling after cardiac injury. The aim of the present article is to review the structure, function, regulation of MMPs and to discuss their potential role in the pathogenesis of acute coronary syndromes, as well as their contribution and usefullness in the setting of the disease.

Increased matrix metalloproteinase-8 and -9 activity in patients with infarct rupture after myocardial infarction

NARCIS (Netherlands)

Borne, S.W.M. van den; Cleutjens, J.P.M.; Hanemaaijer, R.; Creemers, E.E.; Smits, J.F.M.; Daemen, M.J.A.P.; Blankesteijn, W.M.

2009-01-01

Background: Infarct rupture is a usually fatal complication of myocardial infarction (MI), for which no molecular mechanism has been described in humans. Experimental evidence in mouse models suggests that the degradation of the extracellular matrix by matrix metalloproteinases (MMPs) plays an

Role of matrix metalloprotease-2 in oxidant activation of Ca ATPase ...

Indian Academy of Sciences (India)

Unknown

We sought to determine the role of matrix metalloprotease-2 (MMP-2) ... Ca2+ overload in cells and tissues (Bennet and Williams. 1993; Ghosh et ..... tease balance in favour of the protease. ... This work was partly supported by the Life Science.

Plastic substrates for active matrix liquid crystal display incapable of withstanding processing temperature of over 200.degree. C and method of fabrication

Energy Technology Data Exchange (ETDEWEB)

Carey, Paul G. (Mountain View, CA); Smith, Patrick M. (San Ramon, CA); Havens, John (San Diego, CA); Jones, Phil (Marlborough, GB)

1999-01-01

Bright-polarizer-free, active-matrix liquid crystal displays (AMLCDs) are formed on plastic substrates. The primary components of the display are a pixel circuit fabricated on one plastic substrate, an intervening liquid-crystal material, and a counter electrode on a second plastic substrate. The-pixel circuit contains one or more thin-film transistors (TFTs) and either a transparent or reflective pixel electrode manufactured at sufficiently low temperatures to avoid damage to the plastic substrate. Fabrication of the TFTs can be carried out at temperatures less than 100.degree. C. The liquid crystal material is a commercially made nematic curvilinear aligned phase (NCAP) film. The counter electrode is comprised of a plastic substrate coated with a transparent conductor, such as indium-doped tin oxide (ITO). By coupling the active matrix with NCAP, a high-information content can be provided in a bright, fully plastic package. Applications include any low cost portable electronics containing flat displays where ruggedization of the display is desired.

Single-crystal structure, photophysical characteristics and electroluminescent properties of bis(2-(4-trifluoromethyl-2-hydroxyphenyl)benzothiazolate)zinc

International Nuclear Information System (INIS)

Xu Huixia; Yue, Yan; Wang Hua; Chen Liuqing; Hao Yuying; Xu Bingshe

2012-01-01

In this paper, a zinc (II) complex of Zn 2 (4-tfmBTZ) 4 (4-tfmBTZ=2-(4-trifluoromethyl-2-hydroxyphenyl)benzothiazolate) was reported. Via combination of experimental and theoretical approaches, its molecular structure, photophysical characteristics, electronic structure and electroluminescent properties were investigated. The results indicate that Zn 2 (4-tfmBTZ) 4 exists as five-coordinate geometric structure and two zinc atoms are bridged by oxygen atoms. The intense absorption band was located at 404 nm, which mainly originate from the transition HOMO−1 to LUMO+2. The blue-light emission was observed in tetrahydrofuran solution and thin film. White-light emission with four emission peaks was observed with CIE coordinate of (0.29, 0.33) and a higher CRI of 85.1 by fabricating bilayer device using Zn 2 (4-tfmBTZ) 4 as electron-transport and NPB as hole-transport material. - Highlights: ► The single-crystal and electronic structures of Zn 2 (4-tfmBTZ) 4 . ► The multicolor emission of Zn 2 (4-tfmBTZ) 4 were realized by the simple devices. ► White OLED is achieved with particularly high color rending index (CRI) by the emission of Zn 2 (4-tfmBTZ) 4 .

An asynchronous, pipelined, electronic acquisition system for Active Matrix Flat-Panel Imagers (AMFPIs)

CERN Document Server

Huang, W; Berry, J; Maolinbay, M; Martelli, C; Mody, P; Nassif, S; Yeakey, M

1999-01-01

The development of a full-custom electronic acquisition system designed for readout of large-area active matrix flat-panel imaging arrays is reported. The arrays, which comprise two-dimensional matrices of pixels utilizing amorphous silicon thin-film transistors, are themselves under development for a wide variety of X-ray imaging applications. The acquisition system was specifically designed to facilitate detailed, quantitative investigations of the properties of these novel imaging arrays and contains significant enhancements compared to a previously developed acquisition system. These enhancements include pipelined preamplifier circuits to allow faster readout speed, expanded addressing capabilities allowing a maximum of 4096 array data lines, and on-board summing of image frames. The values of many acquisition system parameters, including timings and voltages, may be specified and downloaded from a host computer. Once acquisition is enabled, the system operates asynchronously of its host computer. The sys...

The dynamic extracellular matrix: intervention strategies during heart failure and atherosclerosis

NARCIS (Netherlands)

Heeneman, Sylvia; Cleutjens, Jack P.; Faber, Birgit C.; Creemers, Esther E.; van Suylen, Robert-Jan; Lutgens, Esther; Cleutjens, Kitty B.; Daemen, Mat J.

2003-01-01

The extracellular matrix is no longer seen as the static embedding in which cells reside; it has been shown to be involved in cell proliferation, migration and cell-cell interactions. Turnover of the different extracellular matrix components is an active process with multiple levels of regulation.

A matrix-focused structure-activity and binding site flexibility study of quinolinol inhibitors of botulinum neurotoxin serotype A.

Science.gov (United States)

Harrell, William A; Vieira, Rebecca C; Ensel, Susan M; Montgomery, Vicki; Guernieri, Rebecca; Eccard, Vanessa S; Campbell, Yvette; Roxas-Duncan, Virginia; Cardellina, John H; Webb, Robert P; Smith, Leonard A

2017-02-01

Our initial discovery of 8-hydroxyquinoline inhibitors of BoNT/A and separation/testing of enantiomers of one of the more active leads indicated considerable flexibility in the binding site. We designed a limited study to investigate this flexibility and probe structure-activity relationships; utilizing the Betti reaction, a 36 compound matrix of quinolinol BoNT/A LC inhibitors was developed using three 8-hydroxyquinolines, three heteroaromatic amines, and four substituted benzaldehydes. This study has revealed some of the most effective quinolinol-based BoNT/A inhibitors to date, with 7 compounds displaying IC 50 values ⩽1μM and 11 effective at ⩽2μM in an ex vivo assay. Published by Elsevier Ltd.

Superior integrin activating capacity and higher adhesion to fibrinogen matrix in buffy coat-derived platelet concentrates (PCs) compared to PRP-PCs.

Science.gov (United States)

Beshkar, Pezhman; Hosseini, Ehteramolsadat; Ghasemzadeh, Mehran

2018-02-01

Regardless of different sources, methods or devices which are applied for preparation of therapeutic platelets, these products are generally isolated from whole blood by the sedimentation techniques which are based on PRP or buffy coat (BC) separation. As a general fact, platelet preparation and storage are also associated with some deleterious changes that known as platelet storage lesion (PSL). Although these alternations in platelet functional activity are aggravated during storage, whether technical issues within preparation can affect integrin activation and platelet adhesion to fibrinogen were investigated in this study. PRP- and BC-platelet concentrates (PCs) were subjected to flowcytometry analysis to examine the expression of platelet activation marker, P-selectin as well as active confirmation of the GPIIb/IIIa (α IIb β 3 ) on day 0, 1, 3 and 5 post-storage. Platelet adhesion to fibrinogen matrix was evaluated by fluorescence microscopy. Glucose concentration and LDH activity were also measured by colorimetric methods. The increasing P-selectin expression during storage was in a reverse correlation with PAC-1 binding (r = -0.67; p = .001). PRP-PCs showed the higher level of P-selectin expression than BC-PCs, whereas the levels of PAC-1 binding and platelet adhesion to fibrinogen matrix were significantly lower in PRP-PCs. Higher levels of active confirmation of the GPIIb/IIIa in BC-PCs were also associated with greater concentration of glucose in these products. We demonstrated the superior capacities of integrin activation and adhesion to fibrinogen for BC-PCs compared to those of PRP-PCs. These findings may provide more advantages for BC method of platelet preparation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis and Electroluminescent Properties of Julolidine-π-Juloidine Type Materials with the Bulky Adamantane Groups

Energy Technology Data Exchange (ETDEWEB)

Lee, Kum Hee; Yoon, Seung Soo [Sungkyunkwan Univ., Suwon (Korea, Republic of); Lee, Seok Jae; Kim, Young Kwan [Hongik Univ., Seoul (Korea, Republic of)

2012-11-15

A main problem of red emitting material, which contributes to their low EL performances, is the concentration quenching due to the effective self aggregation and the consequent formation of excimers. To avoid this drawback and thus improve the EL properties of red fluorescent OLED devices, many synthetic efforts have been conducted to develop new emitting materials with the structural motifs to suppress self-aggregation by the weakening intermolecular attractive interactions. Particularly, the introduction of bulky moieties in the emitters would provide the steric hindrance between emitting materials in solid state devices and thus reduce the self-aggregation. Nevertheless, EL performances of red materials still need to be improved for the practical applications. In conclusion, we designed and synthesized three julolidine-π-juloidine type emitting materials (1-3) with the bulky adamantane groups. To study their electroluminescent properties, the multilayered OLED devices with the structure of ITO/NPB (40 nm)/ADN : 1-3 (x%) (20 nm)/Alq{sub 3} (40 nm)/Liq (2 nm)/Al were fabricated. All devices using emitters 1-3 showed the efficient emissions, in which their EL performances depend on the structure of emitters sensitively. Particularly, a device using emitter 3 exhibited the efficient orange-red emission with the luminous and power efficiencies of 4.79 cd/A and 1.76 lm/W at 20 mA/cm{sup 2}, respectively. The CIE coordinates of this device was (0.57, 0.42) at 7.0 V.

Correcting the effects of the matrix using capture gamma-ray spectrometry: Application to measurement by Active Neutron Interrogation; Correction des effets de matrice par spectrometrie des rayonnements gamma de capture: Application a la mesure par Interrogation Neutronique Active (I.N.A.)

Energy Technology Data Exchange (ETDEWEB)

Baudry, G.

2003-11-15

In the field of the measurement of low masses of fissile material ({sup 235}U, {sup 239}Pu, {sup 241}Pu) in radioactive waste drums, the Active Neutron Interrogation is a non-destructive method achieving good results. It does however remain reliant upon uncertainties related to the matrix effects on interrogation and fission neutrons. The aim of this thesis is to develop a correction method able to take into account these matrix effects by quantifying the amount of absorbent materials (chlorine and hydrogen) in a 118- liter homogeneous matrix. The main idea is to use the gamma-ray spectrometry of gamma emitted by neutron captures to identify and quantify the composition of the matrix. An indicator from its chlorine content is then deduced in order to choose the calibration coefficient which best represents the real composition of the matrix. This document firstly presents the needs of control and characterization of radioactive objects, and the means used in the field of nuclear measurement. Emphases is put in particular on the Active Neutron Interrogation method. The matrices of interest are those made of light technological waste (density {<=} 0,4 g/cm{sup 3}) containing hydrogenated and chlorinated materials. The advantages of gamma-rays emitted by neutron captures for the determination of a chlorine content indicator of the matrices and the principles of the correction method are then explained. Measurements have been firstly realized with an existing Neutron Interrogation device (PROMETHEE 6). Such measurements have proven its inadequacy: no signal from the matrix hydrogen was detected, due to an intense signal from the polyethylene contained in some cell elements. Moreover, the matrix chlorine content appeared difficult to be measured. A new and specific device, named REGAIN and dedicated to active gamma-rays spectrometry, was defined with the Monte-Carlo N-Particle (MCNP) code. The experiments conducted with this new device made it possible to detect the

Structured decomposition design of partial Mueller matrix polarimeters.

Science.gov (United States)

Alenin, Andrey S; Scott Tyo, J

2015-07-01

Partial Mueller matrix polarimeters (pMMPs) are active sensing instruments that probe a scattering process with a set of polarization states and analyze the scattered light with a second set of polarization states. Unlike conventional Mueller matrix polarimeters, pMMPs do not attempt to reconstruct the entire Mueller matrix. With proper choice of generator and analyzer states, a subset of the Mueller matrix space can be reconstructed with fewer measurements than that of the full Mueller matrix polarimeter. In this paper we consider the structure of the Mueller matrix and our ability to probe it using a reduced number of measurements. We develop analysis tools that allow us to relate the particular choice of generator and analyzer polarization states to the portion of Mueller matrix space that the instrument measures, as well as develop an optimization method that is based on balancing the signal-to-noise ratio of the resulting instrument with the ability of that instrument to accurately measure a particular set of desired polarization components with as few measurements as possible. In the process, we identify 10 classes of pMMP systems, for which the space coverage is immediately known. We demonstrate the theory with a numerical example that designs partial polarimeters for the task of monitoring the damage state of a material as presented earlier by Hoover and Tyo [Appl. Opt.46, 8364 (2007)10.1364/AO.46.008364APOPAI1559-128X]. We show that we can reduce the polarimeter to making eight measurements while still covering the Mueller matrix subspace spanned by the objects.

Matrix theory

CERN Document Server

Franklin, Joel N

2003-01-01

Mathematically rigorous introduction covers vector and matrix norms, the condition-number of a matrix, positive and irreducible matrices, much more. Only elementary algebra and calculus required. Includes problem-solving exercises. 1968 edition.

Matrix Metalloproteinase-9/Neutrophil Gelatinase-Associated Lipocalin Complex Activity in Human Glioma Samples Predicts Tumor Presence and Clinical Prognosis

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Ming-Fa Liu

2015-01-01

Full Text Available Matrix metalloproteinase-9/neutrophil gelatinase-associated lipocalin (MMP-9/NGAL complex activity is elevated in brain tumors and may serve as a molecular marker for brain tumors. However, the relationship between MMP-9/NGAL activity in brain tumors and patient prognosis and treatment response remains unclear. Here, we compared the clinical characteristics of glioma patients with the MMP-9/NGAL activity measured in their respective tumor and urine samples. Using gelatin zymography assays, we found that MMP-9/NGAL activity was significantly increased in tumor tissues (TT and preoperative urine samples (Preop-1d urine. Activity was reduced by seven days after surgery (Postop-1w urine and elevated again in cases of tumor recurrence. The MMP-9/NGAL status correlated well with MRI-based tumor assessments. These findings suggest that MMP-9/NGAL activity could be a novel marker to detect gliomas and predict the clinical outcome of patients.

Synthesis and electroluminescence characterization of a new aluminum complex, [8-hydroxyquinoline] bis [2, 2'bipyridine] aluminum Al(Bpy)2q

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Rahul, Kumar; Ritu, Srivastava; Punita, Singh

2016-01-01

We have synthesized and characterized a new electroluminescent material, [8-hydroxyquinoline] bis [2,2'bipyridine] aluminum. A solution of this material Al(Bpy)2q in toluene showed absorption maxima at 380 nm, which was attributed to the moderate energy (π-π*) transitions of the aromatic rings. The photoluminescence spectrum of Al(Bpy)2q in the toluene solution showed a peak at 518 nm. This material shows thermal stability up to 300 °C. The structure of the device is ITO/F4-TCNQ (1 nm)/α-NPD (35 nm)/Al(Bpy)2q (35 nm)/ BCP (6 nm)/Alq3 (28 nm)/LiF (1 nm)/Al (150 nm). This device exhibited a luminescence peak at 515 nm (CIE coordinates, x = 0.32, y = 0.49). The maximum luminescence of the device was 214 cd/m2 at 21 V. The maximum current efficiency of OLED was 0.12 cd/A at 13 V and the maximum power efficiency was 0.03 lm/W at 10 V.

Carrier injection and recombination processes in perovskite CH3NH3PbI3 solar cells studied by electroluminescence spectroscopy

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Handa, Taketo; Okano, Makoto; Tex, David M.; Shimazaki, Ai; Aharen, Tomoko; Wakamiya, Atsushi; Kanemitsu, Yoshihiko

2016-02-01

Organic-inorganic hybrid perovskite materials, CH3NH3PbX3 (X = I and Br), are considered as promising candidates for emerging thin-film photovoltaics. For practical implementation, the degradation mechanism and the carrier dynamics during operation have to be clarified. We investigated the degradation mechanism and the carrier injection and recombination processes in perovskite CH3NH3PbI3 solar cells using photoluminescence (PL) and electroluminescence (EL) imaging spectroscopies. By applying forward bias-voltage, an inhomogeneous distribution of the EL intensity was clearly observed from the CH3NH3PbI3 solar cells. By comparing the PL- and EL-images, we revealed that the spatial inhomogeneity of the EL intensity is a result of the inhomogeneous luminescence efficiency in the perovskite layer. An application of bias-voltage for several tens of minutes in air caused a decrease in the EL intensity and the conversion efficiency of the perovskite solar cells. The degradation mechanism of perovskite solar cells under bias-voltage in air is discussed.

Matrix metalloproteinase-2 of human carotid atherosclerotic plaques promotes platelet activation. Correlation with ischaemic events.

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Lenti, Massimo; Falcinelli, Emanuela; Pompili, Marcella; de Rango, Paola; Conti, Valentina; Guglielmini, Giuseppe; Momi, Stefania; Corazzi, Teresa; Giordano, Giuseppe; Gresele, Paolo

2014-06-01

Purified active matrix metalloproteinase-2 (MMP-2) is able to promote platelet aggregation. We aimed to assess the role of MMP-2 expressed in atherosclerotic plaques in the platelet-activating potential of human carotid plaques and its correlation with ischaemic events. Carotid plaques from 81 patients undergoing endarterectomy were tested for pro-MMP-2 and TIMP-2 content by zymography and ELISA. Plaque extracts were incubated with gel-filtered platelets from healthy volunteers for 2 minutes before the addition of a subthreshold concentration of thrombin receptor activating peptide-6 (TRAP-6) and aggregation was assessed. Moreover, platelet deposition on plaque extracts immobilised on plastic coverslips under high shear-rate flow conditions was measured. Forty-three plaque extracts (53%) potentiated platelet aggregation (+233 ± 26.8%), an effect prevented by three different specific MMP-2 inhibitors (inhibitor II, TIMP-2, moAb anti-MMP-2). The pro-MMP-2/TIMP-2 ratio of plaques potentiating platelet aggregation was significantly higher than that of plaques not potentiating it (3.67 ± 1.21 vs 1.01 ± 0.43, p<0.05). Moreover, the platelet aggregation-potentiating effect, the active-MMP-2 content and the active MMP-2/pro-MMP-2 ratio of plaque extracts were significantly higher in plaques from patients who developed a subsequent major cardiovascular event. In conclusion, atherosclerotic plaques exert a prothrombotic effect by potentiating platelet activation due to their content of MMP-2; an elevated MMP-2 activity in plaques is associated with a higher rate of subsequent ischaemic cerebrovascular events.

Spatially patterned matrix elasticity directs stem cell fate

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Yang, Chun; DelRio, Frank W.; Ma, Hao; Killaars, Anouk R.; Basta, Lena P.; Kyburz, Kyle A.; Anseth, Kristi S.

2016-08-01

There is a growing appreciation for the functional role of matrix mechanics in regulating stem cell self-renewal and differentiation processes. However, it is largely unknown how subcellular, spatial mechanical variations in the local extracellular environment mediate intracellular signal transduction and direct cell fate. Here, the effect of spatial distribution, magnitude, and organization of subcellular matrix mechanical properties on human mesenchymal stem cell (hMSCs) function was investigated. Exploiting a photodegradation reaction, a hydrogel cell culture substrate was fabricated with regions of spatially varied and distinct mechanical properties, which were subsequently mapped and quantified by atomic force microscopy (AFM). The variations in the underlying matrix mechanics were found to regulate cellular adhesion and transcriptional events. Highly spread, elongated morphologies and higher Yes-associated protein (YAP) activation were observed in hMSCs seeded on hydrogels with higher concentrations of stiff regions in a dose-dependent manner. However, when the spatial organization of the mechanically stiff regions was altered from a regular to randomized pattern, lower levels of YAP activation with smaller and more rounded cell morphologies were induced in hMSCs. We infer from these results that irregular, disorganized variations in matrix mechanics, compared with regular patterns, appear to disrupt actin organization, and lead to different cell fates; this was verified by observations of lower alkaline phosphatase (ALP) activity and higher expression of CD105, a stem cell marker, in hMSCs in random versus regular patterns of mechanical properties. Collectively, this material platform has allowed innovative experiments to elucidate a novel spatial mechanical dosing mechanism that correlates to both the magnitude and organization of spatial stiffness.

CELLULAR CONTROL OF CONNECTIVE TISSUE MATRIX TENSION†

Science.gov (United States)

Langevin, Helene M.; Nedergaard, Maiken; Howe, Alan

2013-01-01

The biomechanical behavior of connective tissue in response to stretching is generally attributed to the molecular composition and organization of its extracellular matrix. It also is becoming apparent that fibroblasts play an active role in regulating connective tissue tension. In response to static stretching of the tissue, fibroblasts expand within minutes by actively remodeling their cytoskeleton. This dynamic change in fibroblast shape contributes to the drop in tissue tension that occurs during viscoelastic relaxation. We propose that this response of fibroblasts plays a role in regulating extracellular fluid flow into the tissue, and protects against swelling when the matrix is stretched. This article reviews the evidence supporting possible mechanisms underlying this response including autocrine purinergic signaling. We also discuss fibroblast regulation of connective tissue tension with respect to lymphatic flow, immune function and cancer. PMID:23444198

Cellular control of connective tissue matrix tension.

Science.gov (United States)

Langevin, Helene M; Nedergaard, Maiken; Howe, Alan K

2013-08-01

The biomechanical behavior of connective tissue in response to stretching is generally attributed to the molecular composition and organization of its extracellular matrix. It also is becoming apparent that fibroblasts play an active role in regulating connective tissue tension. In response to static stretching of the tissue, fibroblasts expand within minutes by actively remodeling their cytoskeleton. This dynamic change in fibroblast shape contributes to the drop in tissue tension that occurs during viscoelastic relaxation. We propose that this response of fibroblasts plays a role in regulating extracellular fluid flow into the tissue, and protects against swelling when the matrix is stretched. This article reviews the evidence supporting possible mechanisms underlying this response including autocrine purinergic signaling. We also discuss fibroblast regulation of connective tissue tension with respect to lymphatic flow, immune function, and cancer. Copyright © 2013 Wiley Periodicals, Inc.

Fuzzy vulnerability matrix

International Nuclear Information System (INIS)

Baron, Jorge H.; Rivera, S.S.

2000-01-01

The so-called vulnerability matrix is used in the evaluation part of the probabilistic safety assessment for a nuclear power plant, during the containment event trees calculations. This matrix is established from what is knows as Numerical Categories for Engineering Judgement. This matrix is usually established with numerical values obtained with traditional arithmetic using the set theory. The representation of this matrix with fuzzy numbers is much more adequate, due to the fact that the Numerical Categories for Engineering Judgement are better represented with linguistic variables, such as 'highly probable', 'probable', 'impossible', etc. In the present paper a methodology to obtain a Fuzzy Vulnerability Matrix is presented, starting from the recommendations on the Numerical Categories for Engineering Judgement. (author)

Green's matrix for a second-order self-adjoint matrix differential operator

International Nuclear Information System (INIS)

Sisman, Tahsin Cagri; Tekin, Bayram

2010-01-01

A systematic construction of the Green's matrix for a second-order self-adjoint matrix differential operator from the linearly independent solutions of the corresponding homogeneous differential equation set is carried out. We follow the general approach of extracting the Green's matrix from the Green's matrix of the corresponding first-order system. This construction is required in the cases where the differential equation set cannot be turned to an algebraic equation set via transform techniques.

Binding of matrix metalloproteinase inhibitors to extracellular matrix: 3D-QSAR analysis.

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Zhang, Yufen; Lukacova, Viera; Bartus, Vladimir; Nie, Xiaoping; Sun, Guorong; Manivannan, Ethirajan; Ghorpade, Sandeep R; Jin, Xiaomin; Manyem, Shankar; Sibi, Mukund P; Cook, Gregory R; Balaz, Stefan

2008-10-01

Binding to the extracellular matrix, one of the most abundant human protein complexes, significantly affects drug disposition. Specifically, the interactions with extracellular matrix determine the free concentrations of small molecules acting in tissues, including signaling peptides, inhibitors of tissue remodeling enzymes such as matrix metalloproteinases, and other drug candidates. The nature of extracellular matrix binding was elucidated for 63 matrix metalloproteinase inhibitors, for which the association constants to an extracellular matrix mimic were reported here. The data did not correlate with lipophilicity as a common determinant of structure-nonspecific, orientation-averaged binding. A hypothetical structure of the binding site of the solidified extracellular matrix surrogate was analyzed using the Comparative Molecular Field Analysis, which needed to be applied in our multi-mode variant. This fact indicates that the compounds bind to extracellular matrix in multiple modes, which cannot be considered as completely orientation-averaged and exhibit structural dependence. The novel comparative molecular field analysis models, exhibiting satisfactory descriptive and predictive abilities, are suitable for prediction of the extracellular matrix binding for the untested chemicals, which are within applicability domains. The results contribute to a better prediction of the pharmacokinetic parameters such as the distribution volume and the tissue-blood partition coefficients, in addition to a more imminent benefit for the development of more effective matrix metalloproteinase inhibitors.

Molecular Cues Guiding Matrix Stiffness in Liver Fibrosis

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Takaoki Saneyasu

2016-01-01

Full Text Available Tissue and matrix stiffness affect cell properties during morphogenesis, cell growth, differentiation, and migration and are altered in the tissue remodeling following injury and the pathological progression. However, detailed molecular mechanisms underlying alterations of stiffness in vivo are still poorly understood. Recent engineering technologies have developed powerful techniques to characterize the mechanical properties of cell and matrix at nanoscale levels. Extracellular matrix (ECM influences mechanical tension and activation of pathogenic signaling during the development of chronic fibrotic diseases. In this short review, we will focus on the present knowledge of the mechanisms of how ECM stiffness is regulated during the development of liver fibrosis and the molecules involved in ECM stiffness as a potential therapeutic target for liver fibrosis.

Matrix calculus

CERN Document Server

Bodewig, E

1959-01-01

Matrix Calculus, Second Revised and Enlarged Edition focuses on systematic calculation with the building blocks of a matrix and rows and columns, shunning the use of individual elements. The publication first offers information on vectors, matrices, further applications, measures of the magnitude of a matrix, and forms. The text then examines eigenvalues and exact solutions, including the characteristic equation, eigenrows, extremum properties of the eigenvalues, bounds for the eigenvalues, elementary divisors, and bounds for the determinant. The text ponders on approximate solutions, as well

Neutrino mass matrix

International Nuclear Information System (INIS)

Strobel, E.L.

1985-01-01

Given the many conflicting experimental results, examination is made of the neutrino mass matrix in order to determine possible masses and mixings. It is assumed that the Dirac mass matrix for the electron, muon, and tau neutrinos is similar in form to those of the quarks and charged leptons, and that the smallness of the observed neutrino masses results from the Gell-Mann-Ramond-Slansky mechanism. Analysis of masses and mixings for the neutrinos is performed using general structures for the Majorana mass matrix. It is shown that if certain tentative experimental results concerning the neutrino masses and mixing angles are confirmed, significant limitations may be placed on the Majorana mass matrix. The most satisfactory simple assumption concerning the Majorana mass matrix is that it is approximately proportional to the Dirac mass matrix. A very recent experimental neutrino mass result and its implications are discussed. Some general properties of matrices with structure similar to the Dirac mass matrices are discussed

Assessment of Matrix Metalloproteinases by Gelatin Zymography.

Science.gov (United States)

Cathcart, Jillian

2016-01-01

Matrix metalloproteinases are endopeptidases responsible for remodeling of the extracellular matrix and have been identified as critical contributors to breast cancer progression. Gelatin zymography is a valuable tool which allows the analysis of MMP expression. In this approach, enzymes are resolved electrophoretically on a sodium dodecyl sulfate-polyacrylamide gel copolymerized with the substrate for the MMP of interest. Post electrophoresis, the enzymes are refolded in order for proteolysis of the incorporated substrate to occur. This assay yields valuable information about MMP isoforms or changes in activation and can be used to analyze the role of MMPs in normal versus pathological conditions.

Functional proteomic of Matrix Metallo-proteinases (MMP) dedicated to the detection of active forms of MMP in complex proteome

International Nuclear Information System (INIS)

David, A.

2007-07-01

The Matrix Metallo-proteinases (M.M.P.) represent a family of Zinc dependent extracellular proteinases able to cleave collectively all the proteins constituting the extracellular matrix. Currently, 23 human M.M.P. have been identified and are characterized by their sequence in amino-acids and their highly conserved 3 D structure. These enzymes are expressed constitutively during the tissue remodeling process. Their over-expression in various diseases tightly related to inflammatory processes (arthritis, emphysema, cancer) described M.M.P. as choice therapeutic targets. However, as the tissue remodeling implicates modification of cellular contacts, M.M.P. appear currently as proteins involved in signalling pathways. Recent works demonstrating that M.M.P. are able to cleave substrates, which are different than proteins constituting the extracellular matrix, reinforce this vision. In order to identify the individual role and the protein expression level of M.M.P. in pathological context, we developed a new technique of functional proteomics dedicated to the detection of active forms of M.M.P. in tumour samples. This technique relied on the development of a new photoaffinity probe, based on the structure of a potent phosphinic inhibitor of M.M.P., allowing targeting and isolating active forms of M.M.P. by photoaffinity labelling. Furthermore, as the new developed probe incorporated a radioactive element, photoaffinity labelling permitted to radiolabel the targeted proteins. This probe demonstrated in vitro its remarkable ability to covalently modify the h M.M.P.-12, with a singular cross-linking yield, determined at 42 %, displaying an extremely sensitive detection (2.5 fmoles of h M.M.P.-12). When added to complex proteome, the photoaffinity probe presents the same sensibility of detection for the h M.M.P.-12 (5 fmoles); importantly, in this case, h M.M.P.-12 represents only 0.001 % of the totality of the proteins present in the sample. Moreover, this technique allows

Wogonin Suppresses the Activity of Matrix Metalloproteinase-9 and Inhibits Migration and Invasion in Human Hepatocellular Carcinoma

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Ming Hong

2018-02-01

Full Text Available As one of the major active ingredients in Radix Scutellariae, wogonin has been shown to be associated with various pharmacological activities on cancer cell growth, apoptosis, and cell invasion and migration. Here, we demonstrated that wogonin may harbor potential anti-metastatic activities in hepatocarcinoma (HCC. The anti-metastasis potential of wogonin and its underlying mechanisms were evaluated by ligand–protein docking approach, surface plasmon resonance assay, and in vitro gelatin zymography studies. Our results showed that wogonin (100 μM, 50 μM suppressed MHCC97L and PLC/PRF/5 cells migration and invasion in vitro. The docking approach and surface plasmon resonance assay indicated that the potential binding affinity between wogonin and matrix metalloproteinase-9 (MMP-9 may lead to inhibition of MMP-9 activity and further leads to suppression of tumor metastasis. This conclusion was further verified by Western blot results and gelatin zymography analysis. Wogonin might be a potent treatment option for disrupting the tumor metastasis that favors HCC development. The potential active targets from computational screening integrated with biomedical study may help us to explore the molecular mechanism of herbal medicines.

New aluminium-rich alkali slag matrix with clay minerals for immobilizing simulated radioactive Sr and Cs waste

International Nuclear Information System (INIS)

Qian Guangren; Sun, Darren Delai; Tay, Joo Hwa

2001-01-01

A new aluminium-rich alkali-activated slag matrix (M-AAS) with clay absorbents has been developed for immobilization of simulated radioactive Sr or Cs waste by introducing metakaolin, natural zeolite and NaOH-treated attapulgite clay minerals into alkali-activated slag matrix (AAS). The results revealed that the additions of metakaolin and clay absorbents into the cementitious matrixes would greatly enhance the distribution ratio, R d , of selective adsorption whether the matrix was OPC matrix or AAS matrix. The new immobilizing matrix M-AAS not only exhibited the strongest selective adsorption for both Sr and Cs ions, but also was characterized by lower porosity and small pore diameter so that it exhibited the lowest leaching rate. Hydration product analyses also demonstrated that (Na+Al)-substituted C-S-H(I) and self-generated zeolite were major hydration products in the M-AAS matrix, which provided this new immobilizing matrix with better selective adsorption on Sr and Cs and lower leaching rate

Gel structure has an impact on pericellular and extracellular matrix deposition, which subsequently alters metabolic activities in chondrocyte-laden PEG hydrogels.

Science.gov (United States)

Nicodemus, G D; Skaalure, S C; Bryant, S J

2011-02-01

While designing poly(ethylene glycol) hydrogels with high moduli suitable for in situ placement is attractive for cartilage regeneration, the impact of a tighter crosslinked structure on the organization and deposition of the matrix is not fully understood. The objectives of this study were to characterize the composition and spatial organization of new matrix as a function of gel crosslinking and study its impact on chondrocytes in terms of anabolic and catabolic gene expression and catabolic activity. Bovine articular chondrocytes were encapsulated in hydrogels with three crosslinking densities (compressive moduli 60, 320 and 590 kPa) and cultured for 25 days. Glycosaminoglycan production increased with culture time and was greatest in the gels with lowest crosslinking. Collagens II and VI, aggrecan, link protein and decorin were localized to pericellular regions in all gels, but their presence decreased with increasing gel crosslinking. Collagen II and aggrecan expression were initially up-regulated in gels with higher crosslinking, but increased similarly up to day 15. Matrix metalloproteinase (MMP)-1 and MMP-13 expression were elevated (∼25-fold) in gels with higher crosslinking throughout the study, while MMP-3 was unaffected by gel crosslinking. The presence of aggrecan and collagen degradation products confirmed MMP activity. These findings indicate that chondrocytes synthesized the major cartilage components within PEG hydrogels, however, gel structure had a significant impact on the composition and spatial organization of the new tissue and on how chondrocytes responded to their environment, particularly with respect to their catabolic expression. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Extremely flexible, transparent, and strain-sensitive electroluminescent device based on ZnS:Cu-polyvinyl butyral composite and silver nanowires

Science.gov (United States)

Jun, Sungwoo; Kim, Youngmin; Ju, Byeong-Kwon; Kim, Jong-Woong

2018-01-01

A multifunctional alternate current electroluminescent device (ACEL) was achieved by compositing ZnS:Cu particles in polyvinyl butyral (PVB) with two layers of percolated silver nanowire (AgNW) electrodes. The strong hydrogen bonding interactions and entanglement of PVB chains considerably strengthened the PVB, and thus, the cured mixture of ZnS:Cu particles and freestanding PVB required no additional support. The device was fabricated by embedding AgNWs on both sides of the ZnS:Cu-PVB composite film using an inverted layer process and intense-pulsed-light treatment. The strong affinity of PVB to the polyvinyl pyrrolidone (PVP) layer, which capped the AgNWs, mechanically stabilized the device to such an extent that it could resist 10,000 bending cycles under a curvature radius of 500 μm. Using AgNW networks in both the top and bottom electrodes made a double-sided light-emitting device that could be applied to wearable lightings or flexible digital signage. The capacitance formed in the device sensitively varied with the applied bending and unfolding, thus demonstrating that the device can also be used as a deformation sensor.