The present invention provides a pharmaceutical composition for preventing or treating cranial nerve diseases, comprising a nucleic acid molecule encoding four kinds of pluripotent factors (Oct-4, Sox2, c-Myc, and Klf4) as an active ingredient, and being used for in vivo gene therapy. According to the present invention, the four kinds of pluripotent factors are expressed in the brain tissue and induce proliferation of astrocytes and neural progenitor cells and angiogenesis, and thereby a damaged brain function is restored.
Law, Fiona
Seo, Jung Hwa
Wang, Ziqing
DeLeon, Jennifer L.
Bolis, Yousstina
Brown, Ashley
Zong, Wei-Xing
Du, Guangwei
Rocheleau, Christian E.
The GTPase Rab5 and phosphatidylinositol-3 phosphate [PI(3) P] coordinately regulate endosome trafficking. Rab5 recruits Vps34, the class III phosphoinositide 3-kinase (PI3K), to generate PI(3) P and recruit PI(3) P-binding proteins. Loss of Rab5 and loss of Vps34 have opposite effects on endosome size, suggesting that our understanding of how Rab5 and PI(3) P cooperate is incomplete. Here, we report a novel regulatory loop whereby Caenorhabditis elegans VPS-34 inactivates RAB-5 via recruitment of the TBC-2 Rab GTPase-activating protein. We found that loss of VPS-34 caused a phenotype with large late endosomes, as with loss of TBC-2, and that Rab5 activity (mice have two Rab5 isoforms, Rab5a and Rab5b) is increased in Vps34-knockout mouse embryonic fibroblasts (Vps34 is also known as PIK3C3 in mammals). We found that VPS-34 is required for TBC-2 endosome localization and that the pleckstrin homology (PH) domain of TBC-2 bound PI(3) P. Deletion of the PH domain enhanced TBC-2 localization to endosomes in a VPS-34dependent manner. Thus, PI(3) P binding of the PH domain might be permissive for another PI(3) P-regulated interaction that recruits TBC2 to endosomes. Therefore, VPS-34 recruits TBC-2 to endosomes to inactivate RAB-5 to ensure the directionality of endosome maturation.
Kim, Hak-Beom
Yoon, Yung Jin
Jeong, Jaeki
Heo, Jungwoo
Jang, Hyungsu
Seo, Jung Hwa
Walker, Bright
Kim, Jin Young
Solution processed perovskite semiconductors have developed rapidly over the past decade to yield excellent performance in both solar cell and light emitting diode devices. Both of these device types are prepared using similar materials and architectures, raising the possibility of perovskite based light emitting solar cells. Recent reports have indicated that some low band gap perovskite solar cells are able to emit infrared light efficiently, however, intermediate band gap perovskite solar cells which emit visible light have not, to the best of our knowledge been deliberately designed or extensively characterized. In this work, we have investigated the use of different electron transport layers in order to minimize energetic barriers to electron injection and extraction in methylammonium lead bromide (MAPbBr(3)) films. We demonstrate that through appropriate band structure engineering, MAPbBr(3) can be used tomake such "peroptronic" light-emitting solar cells, which simultaneously exhibit efficient solar cell power conversion efficiencies over 1% and 0.43 lm W-1 green light emission.
Walker, Bright
Kim, Gi-Hwan
Heo, Jungwoo
Chae, Gil Jo
Park, Jongnam
Seo, Jung Hwa
Kim, Jin Young
Solution-processed CdS field effect transistors (FETs) and solar cells are demonstrated via spin-coating and thermal annealing of soluble cadmium thiolate compounds. The synthesis is carried out in one simple step using cadmium oxide and tertiary alkane thiols. The cadmium thiolates are soluble in organic solvents such as chloroform and may be spin-coated, like organic semiconductors, to form thin films. The cadmium thiolate films decompose rapidly at 300 degrees C toyield semiconducting cadmium sulfide films. FETs are easily fabricated using these films and exhibit electron mobilities of up to 61 cm(2) V-1 s(-1), which compare favourably to FETs prepared from other solution-processed materials such as organic semiconductors, inorganic nanoparticles or chalcogenide films. Initial attempts to prepare hybrid bilayer solar cells were successfully realized by spin-coating a p-type semiconducting polymer layer on top of the n-type CdS film. These devices show significant photocurrent response from both the CdS and polymer layers, indicating that the CdS films are able to participate in photo-induced electron transfer from the polymer to the CdS layer as well as photo-induced hole transfer from CdS to the polymer layer.
Li, Huaping
Risko, Chad
Seo, Jung Hwa
Campbell, Casey
Wu, Guang
Bredas, Jean-Luc
Bazan, Guillermo C.
The reaction between a bulky N-heterocylic carbene (NHC) and C(60) leads to the formation of a thermally stable zwitterionic Lewis acid-base adduct that is connected via a C-C single bond. Low-energy absorption bands with weak oscillator strengths similar to those of n-doped fullerenes were observed for the product, consistent with a net transfer of electron density to the C(60) core. Corroborating information was obtained using UV photoelectron spectroscopy, which revealed that the adduct has an ionization potential similar to 1.5 eV lower than that of C(60). Density functional theory calculations showed that the C-C bond is polarized, with a total charge of +0.84e located on the NHC framework and -0.84e delocalized on the C(60) cage. The combination of reactivity, characterization, and theoretical studies demonstrates that fullerenes can behave as Lewis acids that react with C-based Lewis bases and that the overall process describes n-doping via C-C bond formation.
Seo, Jung Hwa
Namdas, Ebinazar B.
Gutacker, Andrea
Heeger, Alan J.
Bazan, Guillermo C.
We report on solution-processed light emitting field-effect transistors (LEFETs) that incorporate symmetric high work function (WF) source and drain metal electrodes. A key architectural design is the incorporation of a conjugated polyelectrolyte (CPE) electron injection layer atop the emissive layer. The device structure also comprises a hole-transporting layer underneath the emissive layer. Both holes and electrons are injected from stable, high WF metal though the CPE layer leading to electroluminescence near the electron-injecting electrode. With the benefits of the simplicity in device fabrication, the LEFETs incorporating CPEs are interesting structures for integrated organic optoelectronic devices. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3467856]
Cho, Shinuk
Seo, Jung Hwa
Park, Sung Heum
Beaupre, Serge
Leclerc, Mario
Heeger, Alan J.
The thermal stability of the poly(2,7-carbazole) derivative (PCDTBT) is investigated. UV visible absorption spectra and X-ray photoelectron spectroscopy data demonstrate that the electronic structure of PCDTBT is stable in air at annealing temperatures up to 150 degrees C and in N(2) even after exposure to temperatures up to 350 degrees C. Field-effect transistors fabricated with PCDTBT show stable characteristics and hole mobility up to 150 degrees C (air) and 350 degrees C (N(2)).
Seo, Jung Hwa
Yang, Renqiang
Brzezinski, Jacek Z.
Walker, Bright
Bazan, Guillermo C.
Nguyen, Thuc-Quyen
The chemical structures and electronic structures at conjugated polyelectrolyte/Au interfaces demonstrate that conjugated polyelectrolytes with identical backbones but different pendant charges and charge-compensating ions exhibit different electronic properties. This finding shows that counterions and backbone charges enable control of the electronic and chemical nature of critical device interfaces.
The electronic properties of conjugated polyelectrolytes (CPEs) with poly(fluorene-co-phenylene) backbones and different counterions and charges have been investigated using absorption and ultraviolet photoelectron spectroscopy (UPS). The optical energy band gap of CPEs depends mainly on their conjugated backbone and are nearly insensitive to the charges or counterions. UPS measurements reveal that electron injection from Au to polymers with cationic groups is more efficient than for the neutral and anionic counterparts. The vacuum levels of CPEs were also shifted toward higher and lower binding energy, relative to that of Au, depending on the charge and counterion presence, and provide insight into the general alignment of dipoles at the metal/organic interface.
Lee, Sang Kyu
Cho, Shinuk
Tong, Minghong
Seo, Jung Hwa
Heeger, Alan J.
The optical properties and electrical properties of a series of low-band-gap conjugated copolymers, in which alkyl side chains were substituted at various positions, were investigated using donor-acceptor conjugated copolymers consisting of a cyclopentadithiophene derivative and dithienyl-benzothiadiazole. With substituted side chains, the intrinsic properties of the copolymers were significantly altered by perturbations of the intramolecular charge transfer. The absorption of poly[2, 6-(4,4-bis(2-octyl)-4H-cyclopenta-[2,1-b:3,4-b']dithiophene)-alt-4, 7-bis(4-octyl-thiophene-2-yl)benzo-2,1,3-thiadiazole] [PCPDT-ttOTBTOT (P2)], which assumed a tail-tail configuration, tended to blue shift relative to the absorption of poly[2,6-(4,4-bis(2-octyl)-4H-cyclopenta-[2,1-b:3,4-b'] dithiophene)-alt-4,7-bis (thiophene-2-yl)benzo-2,1,3-thiadiazole] [PCPDT-TBTT (P1)]. The absorption of poly[2,6-(4,4-bis(2-octyl)-4H-cyclopenta-[2,1-b: 3, 4-b']dithiophene)-alt-4,7-bis(3-octyl-thiophene-2-yl) benzo-2,1,3-thiadiazole] [PCPDT-hhOTBTOT (P3)], which assumed a head-head configuration, was blue shifted relative to that of P2. The electrical transport properties of field-effect transistors were sensitive to the side chain position. The field-effect mobility in P2 (mu 2 - 1.8 X 10(-3) cm(2)/V s) was slightly lower than that in P1 (mu(1) 4.9 X 10(-3) cm(2)/V s). However, the mobility of P3 was very low (mu(3) 3.8 X 10(-6) cm(2)/V s). Photoexcitation spectroscopy showed that the charge generation efficiency (shown in transient absorption spectra) and polaron pair mobility in P1 and P2 were higher than in P3, yielding P1 and P2 device performances that were better than the performance of devices based on P3. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49:1821-1829, 2011
Seo, Jung Hwa
Namdas, Ebinazar B.
Gutacker, Andrea
Heeger, Alan J.
Bazan, Guillermo C.
We report on solution-processed light emitting field-effect transistors (LEFETs) that incorporate symmetric high work function (WF) source and drain metal electrodes. A key architectural design is the incorporation of a conjugated polyelectrolyte (CPE) electron injection layer atop the emissive layer. The device structure also comprises a hole-transporting layer underneath the emissive layer. Both holes and electrons are injected from stable, high WF metal though the CPE layer leading to electroluminescence near the electron-injecting electrode. With the benefits of the simplicity in device fabrication, the LEFETs incorporating CPEs are interesting structures for integrated organic optoelectronic devices. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3467856]
Seo, Jung Hwa
Gutacker, Andrea
Walker, Bright
Cho, Shinuk
Garcia, Andres
Yang, Renqiang
Nguyen, Thuc-Quyen
Heeger, Alan J.
Bazan, Guillermo C.
To improve injection in n-type organic thin film transistors (OTFTs), a thin conjugated polyelectrolyte (CPE) layer was interposed between electrodes and the semiconductor layer. OTFTs were fabricated with [6,6]-phenyl-C(61) butyric acid methyl ester (PCBM) and Au source and drain contacts. We demonstrate that the insertion of CPEs beneath top-contact Au source/drain electrodes can be a very effective strategy for improving the carrier injection and reducing turn-on threshold voltages of n-channel OTFTs. Ultraviolet photoemission spectroscopy (UPS) indicates that the decrease of the electron injection barrier is consistent with organized dipoles at the metal/organic interface.
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