5,907 research outputs found
Triplet luminescent dinuclear-gold(I) complex-based light-emitting diodes with low turn-on voltage
The electroluminescence (EL) from a dinuclear-gold(I)-chlorate compound containing bridging phosphine ligands [Au 2(dppm)Cl 2] as emitting layer is reported. Devices with a structure Al/Au 2(dppm)Cl 2/indium-tin-oxide demonstrated a uniform emission under the driving voltage below 1 V. The EL emission was from triplet excited state and the emission color of the device was found to depend on the deposition rate of Au 2(dppm)Cl 2, which can be explained as the different aggregation forms of the stacking compound in the deposition process. © 1999 American Institute of Physics.published_or_final_versio
Annealing study of A1/GaSb contact with the use of doppler broadening technique
Using a monoenergetic positron beam, annealing study of the Al/n-GaSb system was performed by monitoring the Doppler broadening of the annihilation radiation as a function of the positron implanting energy. The S-parameter against positron energy data was successfully fitted by a three-layer model (Al/interface/GaSb). The annealing out of the open volume defects in the polycrystalline Al layer was revealed by the decrease in the S-parameter and the increase in the effective diffusion length of the Al layer. For the as-deposited samples, a∼5 nm interfacial region with S-parameter larger than those of the Al overlayer and the bulk was identified. After the 400^ºC annealing, this interfacial region extends to over 40 nm and its S-parameter dramatically drops. This is possibly due to the new phase formation at the interface. Annealing behaviors of SB and L+,B of the GaSb bulk showed the annealing out of positron traps (possibly the VGa-related defect) at 250ºC. However, a further annealing at 400ºC induces the formation of positron traps, which are possibly of another kind of VGa-related defect and the positron shallow trap GaSb antisite.published_or_final_versionProceedings of the 35th Polish Seminar on Positron Annihilation (PSPA), Turawa, Poland, 20-24 September 2004. In Acta Physica Polonica Series A: General Physics, Physics of Condensed Matter, Optics and Quantum Electronics, Atomic and Molecular Physics, Applied Physics, 2005, v. 107 n. 5, p. 874-87
SPOT-Seq-RNA: Predicting protein-RNA complex structure and RNA-binding function by fold recognition and binding affinity prediction
RNA-binding proteins (RBPs) play key roles in RNA metabolism and post-transcriptional regulation. Computational methods have been developed separately for prediction of RBPs and RNA-binding residues by machine-learning techniques and prediction of protein-RNA complex structures by rigid or semiflexible structure-to-structure docking. Here, we describe a template-based technique called SPOT-Seq-RNA that integrates prediction of RBPs, RNA-binding residues, and protein-RNA complex structures into a single package. This integration is achieved by combining template-based structure-prediction software, SPARKS X, with binding affinity prediction software, DRNA. This tool yields reasonable sensitivity (46 %) and high precision (84 %) for an independent test set of 215 RBPs and 5,766 non-RBPs. SPOT-Seq-RNA is computationally efficient for genome-scale prediction of RBPs and protein-RNA complex structures. Its application to human genome study has revealed a similar sensitivity and ability to uncover hundreds of novel RBPs beyond simple homology. The online server and downloadable version of SPOT-Seq-RNA are available at http://sparks-lab.org/server/SPOT-Seq-RNA/
Synthesis and characterization of folate-poly(ethylene glycol) chitosan graft-polyethylenimine as a non-viral carrier for tumor-targeted gene delivery
The use of chitosan and chitosan derivatives for gene delivery is limited due to the low transfection efficiency and difficulty in transfecting into a variety of cell types, including some cancer cells overexpressing folate receptor (FRs). In order to solve this problem, folate (FA) and poly(ethylene glycol) (PEG) was conjugated to chitosan-graft-polyethylenimine (CHI-g-PEI) to enhance water-solubility and the transfection efficiency. In the present study, a cell specific targeting molecule FA was linked on PEG and then grafted the FA-PEG onto CHI-g-PEI. The FA-PEG-grafted CHI-g-PEI (FA-PEG-CHI-g-PEI) effectively condensed the plasmid DNA (pDNA) into nanoparticles with positive surface charge under the suitable nitrogen/phosphorus (N/P) ratio. In vitro, transfection efficiency of the FA-PEG-CHI-g-PEI /pDNA complex in 293T cells and LoVo cells (FRs over-expressing cell lines) increased with increasing N/P ratio under N/P = 15 and was more than 50%, but no significant difference in human lung carcinoma cells (A549) cells (FRs deficient cell lines). Importantly, in vivo luciferase expression showed that the efficiency of FA-PEG-CHI-g-PEI -mediated transfection (50 μg luciferase plasmid (pLuc), N/P ratio = 15) was comparable to that of adenovirus-mediated luciferase transduction (1 × 109 pfu) in melanomabearing mice. It was concluded that FA-PEG-CHI-g-PEI, which has improved transfection efficiency and FRs specificity in vitro and in vivo, may be useful in gene therapy.Key words: Folate poly(ethylene glycol)-chitosan-grafted-polyethylenimine (FA-PEG-CHI-g-PEI), gene transfection, non-virus vector, in vitro, in viv
Stochastic separated flow models with applications in numerical computations of supersonic particle-laden turbulent flows
In this article, three stochastic separated flow models were applied to predict the dispersion of inertial fuel particles in the supersonic turbulent flows. The flow field of continuous phase was simulated by means of Reynolds-averaged Navier–Stokes method with a two-equation turbulence model. Clift’s expression was used to modify the drag force on the particle considering the compressibility effects. The particle-phase statistics were obtained by a secondary-order time-weighed Eulerian method. The ability of those stochastic separated flow models was then compared for predicting the mean particle velocity and the particle dispersion. For obtaining a statistically stationary solution, the stochastic separated flow model required the largest number of computational particles, whereas the improved stochastic separated flow model was found to need the least. The time-series stochastic separation flow model lay in-between. Compared with the other two models, the particle dispersion was over-predicted by the stochastic separated flow model in the supersonic particle-laden boundary layer flow, while the improved stochastic separated flow model was less predictable for the particle spatial distribution in the particle-laden strut-injection flow. Three models could well predict the mean velocities of the particle phase. This study is valuable for selecting a validated model used for predicting the particle dispersion in supersonic turbulent flows
Three kinds of new hybrid projection methods for a finite family of quasi-asymptotically pseudocontractive mappings in Hilbert spaces
Carbon Nanofibers-Based Nanoconfined Liquid Phase Filtration for the Rapid Removal of Chlorinated Pesticides from Ginseng Extracts.
A rapid nanoconfined liquid phase filtration system (NLPF) based on solvent-confined carbon nanofibers/carbon fiber materials (CNFs/CFs) was proposed to effectively remove chlorinated pesticides from ginsenosides-containing ginseng extracts. A series of major parameters that may affect the separation performance of the CNFs-NLPF method were extensively investigated, including the water solubility of nanoconfined solvents, filtration rate, ethanol content of the ginseng extracts, and reusability of the material for repeated adsorption. The developed method showed a high removal efficiency of pesticides (85.5-97.5%), high retainment rate of ginsenosides (95.4-98.9%), and consistent reproducibility (RSD < 11.8%). Furthermore, the feasibility of the CNFs-NLPF technique to be scaled-up for industrial application was systematically explored by analyzing large-volume ginseng extract (1 L), which also verified its excellent modifiable characteristic. This filtration method exhibits promising potential as a practical tool for removing pesticide residues and other organic pollutants in food samples to assure food quality and safeguard human health
Tectonic affinity of the west Qinling terrane (central China): North China or Yangtze?
[33] Neogene (̃14 Ma) basaltic magmatism has occurred in west Qinling, at the northeastern corner of the Tibetan Plateau. Furthermore, U-Pb ages and Hf isotopic data of xenocrystic zircons indicate that the unexposed Neoarchean (2.7-2.5 Ga) basement beneath the Phanerozoic outcrops in west Qinling has affinities with the southern margin of the north China block. The basement has a complex evolution, including the addition of juvenile mantle material at ̃2.7- 2.4 Ga and 1.1-0.8 Ga and reworking at ̃1.8 Ga and possibly at 1.4 Ga. Phanerozoic thermal events at 320-300 Ma, 230 Ma, and 160 Ma also have affected the basement. We interpret the west Qinling orogenic terrane as originally separated from the north China block, joined to the northern Yangtze block during the Meso-Neoproterozoic, and finally involved in the northward subduction and collision of the Yangtze block in the Paleozoic and early Mesozoic and subsequent lithospheric extension in the Jurassic. © 2010 by the American Geophysical Union.published_or_final_versio
Giant schwannoma of thoracic vertebra: A case report
BACKGROUND,It is relatively rare for schwannomas to invade bone, but it is very rare for a large,mass to form concurrently in the paravertebral region. Surgical resection is the,only effective treatment. Because of the extensive tumor involvement and the,many important surrounding structures, the tumor needs to be fully exposed.,Most of the tumors are completely removed by posterior combined open-heart,surgery to relieve spinal cord compression, restore the stability of the spine and,maximize the recovery of nerve and spinal cord function. The main objective of,this article is to present a schwannoma that had invaded the T5 and T6 vertebral,bodies and formed a large paravertebral mass with simultaneous invasion of the,spinal canal and compression of the spinal cord.,CASE SUMMARY,A 40-year-old female suffered from intermittent chest and back pain for 8 years.,Computed tomography and magnetic resonance imaging scans showed a,paravertebral tumor of approximately 86 mm × 109 mm × 116 mm, where the,adjacent T5 and T6 vertebral bodies were invaded by the tumor, the right intervertebral,foramen was enlarged, and the tumor had invaded the spinal canal to,compress the thoracic medulla. The preoperative puncture biopsy diagnosed a,benign schwannoma. Complete resection of the tumor was achieved by a two-step,operation. In the first step, the thoracic surgeon adopted a lateral approach to,separate the thoracic tumor from the lung. In the second step, a spine surgeon,performed a posterior midline approach to dissect the tumor from the vertebral,junction through removal of the tumor from the posterior side and further,resection of the entire T5 and T6 vertebral bodies. The large bone defect was,reconstructed with titanium mesh, and the posterior root arch was nail-fixed. Due,to the large amount of intraoperative bleeding, we performed tumor angioembolization,before surgery to reduce and avoid large intraoperative bleeding. The,postoperative diagnosis of benign schwannoma was confirmed by histochemical,examination. There was no sign of tumor recurrence or spinal instability during,the 2-year follow-up.,CONCLUSION,Giant schwannoma is uncommon. In this case, a complete surgical resection of a,giant thoracic nerve sheath tumor that invaded part of the vertebral body and,compressed the spinal cord was safe and effective
Biomimetic intrafibrillar mineralization of type I collagen with intermediate precursors-loaded mesoporous carriers
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