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981.
We have enhanced color-rendering property of a blue light emitting diode (LED) pumped white LED with yellow emitting Y3Al5O12:Ce3+ (YAG:Ce) phosphor using addition of Pr and Tb as a co-activator and host lattice element, respectively. Pr3+ addition to YAG:Ce phosphor resulted in sharp emission peak at about 610 nm through 1D2→3H4 transition. And when Tb3+ substituted Y3+ sites, Ce3+ emission band shifted to a longer wavelength due to larger crystal field splitting. Y3Al5O12:Ce3+, Pr3+ and (Y1−xTbx)3Al5O12:Ce3+ phosphors were coated on blue LEDs to fabricate white LEDs, respectively, and their color-rendering indices (CRIs, Ra) were measured. As a consequence of the addition of Pr3+ or Tb3+, CRI of the white LEDs improved to be Ra=83 and 80, respectively. Especially, blue LED pumped (Y0.2Tb0.8)3Al5O12:Ce3+ white LED showed both strong luminescence and high color-rendering property. 相似文献
982.
We show that some Drinfeld modules of rank 2 on Bbb Fq[T]{Bbb F}_q[T] with complex multiplication have global minimal models. 相似文献
983.
Heeyeon An Hyewon Jeon Jungyeon Ji Yongchai Kwon Yongjin Chung 《Journal of Energy Chemistry》2021,(7):463-471
In this study,an amine-coordinated cobalt phthalocyanine (CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen ... 相似文献
984.
Neung-Ju Lee In-Cheol Jeong Chang-Wan Jeon Young-Ok Kim Ildoo Chung 《European Polymer Journal》2006,42(12):3352-3359
Polymer-linked PT (podophyllotoxin) conjugates have been designed to improve the therapeutic efficacy of PT. A new PT-conjugate, 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimido-acetamidoglycinylglycine podophyllotoxin ester (ETPA-gly-gly-PT), was synthesized by covalently coupling its hydroxyl group onto the phthalimido monomer through a glycine-glycine-glycine spacer. Its homo- and copolymer with acrylic acid (AA) were prepared by photopolymerization using 2,2-dimethoxy-2-phenylacetophenone (DMP) as a photoinitiator. ETPA-gly-gly-PT and its polymers were characterized by IR and proton NMR spectra. The ETPA-gly-gly-PT content in the copolymer obtained by elemental analysis was 44 wt%. The number-average molecular weights of the polymers determined by gel permeation chromatography were as follows: Mn = 13,500 for poly(ETPA-gly-gly-PT), Mn = 17,000 for poly(ETPA-gly-gly-PT-co-AA). The in vitro antitumor activity of these conjugates and polymers were determined and used to evaluate the potential applications in antitumor drugs. The IC50 values indicated that the synthesized ETPA-gly-gly-PT and its polymers against cancer cells were much better inhibitors than PT. 相似文献
985.
Dr. Heeju Lee Dr. Yong Nam Choi Dr. Dae‐Woon Lim Md. Mahbubur Rahman Dr. Yong‐Il Kim Dr. In Hwa Cho Hyun Wook Kang Jung‐Hye Seo Dr. Cheolho Jeon Prof. Dr. Kyung Byung Yoon 《Angewandte Chemie (International ed. in English)》2015,54(44):13080-13084
The formation of a frustrated Lewis pair consisting of sodium hydride (Na+H?) and a framework‐bound hydroxy proton O(H+) is reported upon H2 treatment of zeolite NaY loaded with Pt nanoparticles (Ptx/NaY). Frustrated Lewis pair formation was confirmed using in situ neutron diffraction and spectroscopic measurements. The activity of the intrazeolite NaH as a size‐selective catalyst was verified by the efficient esterification of acetaldehyde (a small aldehyde) to form the corresponding ester ethyl acetate, whereas esterification of the larger molecule benzaldehyde was unsuccessful. The frustrated Lewis pair (consisting of Na+H? and O(H+)) generated within zeolite NaY may be a useful catalyst for various catalytic reactions which require both H? and H+ ions, such as catalytic hydrogenation or dehydrogenation of organic compounds and activation of small molecules. 相似文献
986.
Reaction of 2,2-difluoro-1-tributylstannylethenyl p-toluenesulfonate (1) with bis(tributyltin) in the presence of 5 mol % Pd(PPh3)4 and 30 equiv LiBr in THF at reflux temperature for 7 h afforded (2,2-difluoroethenylidene)bis(tributylstannane) (2) in a 70% yield. Coupling reaction of 2 with aryl iodides in the presence of 5 mol % Pd(PPh3)4 and 5 mol % CuI in DMF at 80 °C for 3–4 h provided the coupled products 3 in 59–85% yields. 相似文献
987.
The luminescent properties of alkaline earth orthosilicates M2SiO4 (M=Ba, Sr, Ca) doped with Eu2+ ions are investigated. Two emission bands are assigned to the f-d transitions of Eu2+ ions doped into two different cation sites in host lattices confirmed by electron paramagnetic resonance signal. Two emission bands show the different emission color variation with substituting M2+ cations with smaller cations. This behavior is discussed in terms of two competing factors of the crystal field strength and covalence. Also the decay times are in order of 600-1000 ns. These phosphors with maximum excitation of around 370 nm can be applied as a color-tunable phosphor for light-emitting diode based on ultraviolet chip/phosphor technology. 相似文献
988.
PVC membrane electrodes for lead ion based on N,N’-bis(salicylidene)-2,6-pyridinediamine as membrane carrier were prepared. Among their membranes, a membrane electrode (m-3) containing o-NPOE as a plasticizer and 50 mol% additive displays an excellent Nernstian response (29.4 mV/decade) and the limit of detection of −log a (M) = 6.04 to Pb2+ in Pb(NO3)2 solutions at room temperature. It has a rapid response time within 10 s over the entire concentration range. The proposed electrode revealed good selectivity and response for Pb2+ over a wide variety of other metal ions in a pH 5.0 buffer solutions, and good reproducibility of base line in subsequent measurements. 相似文献
989.
Wook Youn Kim Ji-young Jang Yoon Kyung Jeon Doo Hyun Chung Young Goo Kim Chul-Woo Kim 《Experimental & molecular medicine》2014,46(4):e90
Syntenin is a PDZ domain-containing adaptor protein that has been recently shown to regulate migration and invasion in several tumors. Small cell lung cancer (SCLC) is notorious for its invasiveness and strong potential for metastasis. We therefore studied the influence of syntenin on the invasiveness of SCLC. Immunohistochemistry in tumor tissues showed that syntenin was more frequently expressed in small cell carcinomas than other neuroendocrine tumors, such as carcinoids and neuroblastomas, suggesting that syntenin expression may be related to more aggressive forms of neuroendocrine tumors. In SCLC patients, syntenin overexpression in tumor cells was significantly associated with more extensive and advanced disease at the time of diagnosis (P=0.029). Overexpression of syntenin in SCLC cells that were intrinsically syntenin-low increased the invasiveness of cells and led to the induction of extracellular matrix (ECM)-degrading membrane type 1-matrix metalloproteinase (MT1-MMP) and matrix metalloproteinase 2 (MMP2). In contrast, suppression of syntenin in syntenin-high cells was associated with the downregulation of MT1-MMP. Contrary to the results of previous studies using malignant melanomas and breast carcinomas, signaling cascades were shown to be further transduced through p38 MAPK and PI3K/AKT, with activation of SP1 rather than NF-κB, under circumstances not involving ECM interaction. In addition, the upstream molecule focal adhesion kinase was induced by syntenin activation, in spite of the absence of ECM interaction. These results suggest that syntenin might contribute to the invasiveness of SCLC and could be utilized as a new therapeutic target for controlling invasion and metastasis in SCLC. 相似文献
990.
We describe the development, validation, and application of a novel PDMS-based microfluidic device for imaging leukocyte interaction with a biological substrate at defined shear force employing a parallel plate geometry that optimizes experimental throughput while decreasing reagent consumption. The device is vacuum bonded above a standard 6-well tissue culture plate that accommodates a monolayer of endothelial cells, thereby providing a channel to directly observe the kinetics of leukocyte adhesion under defined shear flow. Computational fluid dynamics (CFD) was applied to model the shear stress and the trajectory of leukocytes within the flow channels at a micron length scale. In order to test this model, neutrophil capture, rolling, and deceleration to arrest as a function of time and position was imaged in the transparent channels. Neutrophil recruitment to the substrate proved to be highly sensitive to disturbances in flow streamlines, which enhanced the rate of neutrophil-surface collisions at the entrance to the channels. Downstream from these disturbances, the relationship between receptor mediated deceleration of rolling neutrophils and dose response of stimulation by the chemokine IL-8 was found to provide a functional readout of integrin activation. This microfluidic technique allows detailed kinetic studies of cell adhesion and reveals neutrophil activation within seconds to chemotactic molecules at concentrations in the picoMolar range. 相似文献