This article addresses the design problem of selecting an appropriate relay in amplify-and-forward （AF） cooperative diversity systems. In this regard, this article focuses on relay selection based on partial channel...
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This article addresses the design problem of selecting an appropriate relay in amplify-and-forward （AF） cooperative diversity systems. In this regard, this article focuses on relay selection based on partial channel knowledge only across the source and relay links. In particular, the two fundamental questions will be answered, that is, whether to cooperate and whom to cooperate with. Through answering these two questions, an improved relay selection strategy based on partial relay link, which emphasizes that cooperation happens when necessary, is proposed to aim at maximizing the average mutual information. Then a joint optimization, in terms of power allocation and relay selection, is employed to guarantee a robust performance for relay selection based on partial relay link. Optimum power is allocated between the source and the selected relay to maximize the output signal-to-noise （SNR） at the destination. Simulation results turn out that the improved scheme can achieve better performance than previous work and the robust performance can be guaranteed by employing joint optimization.
A microfiltration process coupled with online coagulation using honeycomb ceramic membranes was used to purify lake water. The turbidity of feed lake water was from 13 to 30 NTU and the suitable dose of the coagulant ...
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A microfiltration process coupled with online coagulation using honeycomb ceramic membranes was used to purify lake water. The turbidity of feed lake water was from 13 to 30 NTU and the suitable dose of the coagulant was 15-30 mg L(-1) by the jar test. The turbidity of the treated lake water after coagulation was about 5 NTU, which was suitable for microfiltration at the optimised operating conditions of 0.2 MPa and 1 m x s(-1). The function of flux as membrane pore size showed that the optimal pore size was 500 nm in the tested four ceramic membranes for treating the lake water. The steady flux of microfiltration increased from 225 to 640 L x m(-2) x h(-1) by coupled with online coagulation, and the turbidity removal increased from 97.2% to 99.5%. The water quality analysis displayed that UV(254), the content of TOC and metal ions by microfiltration with online coagulation were lower than that without coagulation.
Mesoporous silica nanomaterial is one of the most promising candidates as drug carrier for cancer therapy herein, in vitro and in vivo study of silica nanorattle (SN) with mesoporous and rattle type structure as a dru...
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Mesoporous silica nanomaterial is one of the most promising candidates as drug carrier for cancer therapy herein, in vitro and in vivo study of silica nanorattle (SN) with mesoporous and rattle type structure as a drug delivery system was first reported Hydrophobic antitumor drug docetaxel (Dtxl) was loaded into the PEGylated silica nanorattle (SN PEG) with a diameter of 125 nm via electrostatic absorption In human liver, cancer cell Hep G2, the half maximum inhibiting concentration (IC50) of silica nanorattle encapsulated docetaxel (SN PEG Dtxl) was only 7% of that of free Dtxl at 72 h in vivo toxicity assessment showed that both nanocarrier of silica nanorattle (40 mg/kg, single dose) and SN PEG Dtxl (20 mg/kg of Dtxl, three doses) had low systematic toxicity in healty ICR mice The SN PEG Dtxl (20 mg/kg, intravenously) showed greater antitumor activity with about 15% enhanced tumor inhibition rate compared with Taxotere on the marine hepatocardnoma 22 subcutaneous model The results prove that the SN PEG Dtxl has low toxicity and high therapy efficacy, which provides convincing evidence for the silica nanorattle as a promising candidate for a drug delivery system
***-based agricultural machinery monitoring WEBGIS is flexible and dynamic,but this flexibility and dynamic characteristics reduce the performance of ***,it is necessary to use built-in optimization features *** Frame...
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***-based agricultural machinery monitoring WEBGIS is flexible and dynamic,but this flexibility and dynamic characteristics reduce the performance of ***,it is necessary to use built-in optimization features *** Framework,some performance optimization techniques in program design and *** cache technology to reduce the loading of server,and make the designed system work more efficiently.
A large size and high strength Ti-based bulk metallic glass is fabricated from the amorphous powders by the spark plasma sintering (SPS) technique. The sufficient viscous flow induced by the macroscopic temperature un...
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A large size and high strength Ti-based bulk metallic glass is fabricated from the amorphous powders by the spark plasma sintering (SPS) technique. The sufficient viscous flow induced by the macroscopic temperature under a sintering stress is considered as the main mechanism for the densification. During the SPS process, the microscopic temperature gradient was identified, which directly influences the microstructures and in turn the mechanical properties at different regions of the sample. A new phase with an orthorhombic structure (a = 0.48 nm, b = 1.03 nm and c = 0.61 nm) is determined. (C) 2010 Elsevier B.V. All rights reserved.
The plant-specific GRAS/SCL transcription factors play diverse roles in plant development and stress responses. In this study, a poplar SCL gene, PeSCL7, was functionally characterized in Arabidopsis thaliana, especia...
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The plant-specific GRAS/SCL transcription factors play diverse roles in plant development and stress responses. In this study, a poplar SCL gene, PeSCL7, was functionally characterized in Arabidopsis thaliana, especially with regard to its role in abiotic stress resistance. Expression analysis in poplar revealed that PeSCL7 was induced by drought and high salt stresses, but was repressed by gibberellic acid (GA) treatment in leaves. Transient expression of GFP-PeSCL7 in onion epidermal cells revealed that the PeSCL7 protein was localized in the nucleus. Transgenic Arabidopsis plants overexpressing PeSCL7 showed enhanced tolerance to drought and salt treatments. The activity of two stress-responsive enzymes was increased in transgenic seedlings. Taken together, these results suggest that PeSCL7 encodes a member of the stress-responsive GRAS/SCL transcription factors that is potentially useful for engineering drought- and salt-tolerant trees.
The crystallization behavior of Ti-based metallic glassy powders was systematically investigated. The results show a novel metastable nanocrystallization process, i.e. the glassy powders exhibit multi-step phase trans...
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The crystallization behavior of Ti-based metallic glassy powders was systematically investigated. The results show a novel metastable nanocrystallization process, i.e. the glassy powders exhibit multi-step phase transition behavior. For the first exothermic event, the entire glassy phase crystallized into metastable nanocrystals, then a face-centered cubic structured Ni2SnZr and a monoclinic structured TiNi0.8Cu0.2 phases formed by a solid state transition (the second exothermic event). These crystallizations are believed to be driven by the synergetic effect of thermodynamics and kinetics. Crown Copyright (C) 2010 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved.
Adipose-derived stem cells (ASCs) are considered as a promising cell source for cartilage regeneration. However, the heterogeneity of this cell source may affect their ability in cartilage formation. It is therefore n...
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Adipose-derived stem cells (ASCs) are considered as a promising cell source for cartilage regeneration. However, the heterogeneity of this cell source may affect their ability in cartilage formation. It is therefore necessary to establish an efficient method for isolating the cells that have chondrogenic potential. To date, no specific markers have been reported to be able to isolate such a cell population from human adipose tissue. In recent studies, endoglin (CD105) has been known as a relatively specific marker for identifying mesenchymal stem cells, but no studies show it is related to chondrogenic potential of human ASCs. In this study, human cells from adipose tissue were isolated, cultured, and sorted according to CD105 expression. The sorted cells were then subjected to adipogenic, osteogenic, and chondrogenic induction to confirm their multi-potentiality. In adipogenic conditions, CD105 cells showed stronger Oil Red staining and higher expression of adipose-specific genes compared to CD105+ cells. By contrast, CD105+ cells exhibited better osteogenic potential with stronger Alizarin Red staining and higher expression of osteogenic specific genes than CD105 cells. Noticeably, CD105+ cells also exhibited a much stronger chondrogenic potential than CD105 cells, with stronger collagen II staining and higher gene expression of collagen II and aggrecan. Most importantly, CD105+ cells could form a homogeneous cartilage-like tissue when seeded into a biodegradable scaffold and cultured in chondrogenic media for 8 weeks. These results indicate that sorting of ASC subpopulation with CD105 as a marker may allow better in vitro chondrogenesis and thus provide an important implications for cartilage regeneration and reconstruction using autologous cells from adipose tissue. (C) 2010 Elsevier Ltd. All rights reserved.
To establish a potential resource for cell therapy and a developmental model for human diseases, we had isolated three Chinese human embryonic stem cell lines from the inner cell mass of human blastocysts in 2002. All...
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To establish a potential resource for cell therapy and a developmental model for human diseases, we had isolated three Chinese human embryonic stem cell lines from the inner cell mass of human blastocysts in 2002. All the three cell lines were grown on mouse embryonic fibroblasts as feeder cells;one of these cell lines, chHES-3, has maintained its normal karyotype even after being cultured in vitro for more than 100 passages, after the standardization of mouse feeder preparation. Each hES cell line has been completely characterized. All the three cell lines expressed hES-specific markers and pluripotency-related genes. These cells maintained their normal karyotype during long-term culture and displayed a high telomerase activity. When differentiated in vivo and in vitro, the derivatives representing the three germ layers could be observed. Human leukocyte antigen, ABO blood type, and DNA fingerprinting were also performed to provide a unique identity to each cell line. By establishing these hES cell lines, we provide an appropriate in vitro model to study human development and regeneration. All the three cell lines can be obtained for research purposes by placing a request at our website at *** .
In orthogonal frequency division multiple access (OFDMA) uplink system, estimations of time delay and carrier frequency offset (CFO) are both particularly challenging. In IEEE 802.16-based networks, such synchronizati...
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In orthogonal frequency division multiple access (OFDMA) uplink system, estimations of time delay and carrier frequency offset (CFO) are both particularly challenging. In IEEE 802.16-based networks, such synchronization problem can be resolved in initial ranging process. In this paper, exploiting the unique scheme of interleaved OFDMA, a special ranging symbol which has repetitive scheme in time-domain is designed. Furthermore, a novel ranging method for OFDMA system is proposed by utilizing such repetitive characteristic. Compared with the existing methods, this algorithm just need one ranging symbol and can get more correct estimation of time delay, at the same time, it can estimate the integral CFO in OFDMA uplink. Simulations illustrate efficiency of the proposed algorithm over the existing method(1).
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