162 research outputs found

    A Deterministic Equivalent for the Analysis of Non-Gaussian Correlated MIMO Multiple Access Channels

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    Large dimensional random matrix theory (RMT) has provided an efficient analytical tool to understand multiple-input multiple-output (MIMO) channels and to aid the design of MIMO wireless communication systems. However, previous studies based on large dimensional RMT rely on the assumption that the transmit correlation matrix is diagonal or the propagation channel matrix is Gaussian. There is an increasing interest in the channels where the transmit correlation matrices are generally nonnegative definite and the channel entries are non-Gaussian. This class of channel models appears in several applications in MIMO multiple access systems, such as small cell networks (SCNs). To address these problems, we use the generalized Lindeberg principle to show that the Stieltjes transforms of this class of random matrices with Gaussian or non-Gaussian independent entries coincide in the large dimensional regime. This result permits to derive the deterministic equivalents (e.g., the Stieltjes transform and the ergodic mutual information) for non-Gaussian MIMO channels from the known results developed for Gaussian MIMO channels, and is of great importance in characterizing the spectral efficiency of SCNs.Comment: This paper is the revision of the original manuscript titled "A Deterministic Equivalent for the Analysis of Small Cell Networks". We have revised the original manuscript and reworked on the organization to improve the presentation as well as readabilit

    Numerical Simulation on Forced Convection Cooling of Horizontal Ionic Wind with Multi-electrodes

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    Enhancement ofheat transfer plays an important role in the cooling of electronic or refrigeration systems, and its characteristics could strongly affect the stability and performance of such systems. To enhance heat transfer, air cooling of forced convection remains one of the main solutions. For example, conventional rotary-fan air cooling is still dominant in many areas. However, with the increasing of heat generation in these systems, the limitation of the conventional rotary-fan air cooling is become more obvious. So, demands in novel air cooling technology become necessary, e.g., silent and high efficient air cooling. Recently, ionic wind, which has no moving part and is easily miniaturized, shows great potential in heat dissipation and attracts widespread attentions. In this work, ionic wind, which is produced by wire to plate configuration for forced convection enhancement of horizontal flow along the plate, is numerically investigated. Firstly, a multi-physic model, which accounts for electric field, charge distribution, fluid dynamics, and heat transfer phenomenon, is presented. Comparisons between the simulation and literature data are conducted. Results show that better agreements are achieved by the developed model. Secondly, influences of the emitting electrodes numbers are analyzed. Results show that multiple electrodes configuration has higher performance in terms of heat transfer coefficient than that of the single electrode. Investigations are also carried out on the influences of the distances between the emitting electrodes. Thirdly, effects of the main parameters of ionic wind, such as the inlet velocity, and voltage applied on the electrodes etc., are investigated. Finally, by using the multi-physic model of ionic wind, characteristics of the heat transfer are predicted. It is found that the maximum enhancement of average heat transfer coefficient could reach around 150 %

    Carbon dots for specific “off-on” sensing of Co\u3csup\u3e2+\u3c/sup\u3e and EDTA for in vivo bioimaging

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    Fluorescent carbon dots (CDs) were hydrothermally synthesized from a mixture of frozen tofu, ethylenediamine and phosphoric acid in an efficient 64% yield. The resulting CDs exhibit good water solubility, low cytotoxicity, high stability, and excellent biocompatibility. The CDs selectively and sensitively detect Co2+ through fluorescent quenching with a detection limit of 58 nM. Fluorescence can be restored through the introduction of EDTA, and this phenomenon can be used to quantify EDTA in solution with a detection limit of 98 nM. As both analytes are detected by the same CD platform, this is an “off-on” fluorescence sensor for Co2+ and EDTA. The technique\u27s robustness for real-world samples was illustrated by quantifying cobalt in tap water and EDTA in contact lens solution. The CDs were also evaluated for in vivo imaging as they show low cytotoxicity and excellent cellular uptake. In a zebrafish model, the CDs are rapidly adsorbed from the intestine into the liver, and are essentially cleared from the body in 24 h with no appreciable bioaccumulation. Their simple and efficient synthesis, combined with excellent physical and chemical performance, renders these CDs attractive candidates for theranostic applications in targeted “smart” drug delivery and bioimaging

    The Clinical Signifcance of Expression of ERCC1 and PKCalpha in Non-small Cell Lung Cancer

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    Background and objective Excision repair cross-complementing 1 (Excision-Repair Cross-Complementing 1, ERCC1), an important member of the DNA repair gene family, plays a key role in nucleotide excision repair and apoptosis of tumor cells. Protein kinase C-α (Protein kinase C, PKCα), an isozyme in protein kinase C family, is an important signaling molecule in signal transduction pathways of tumors, which has been implicated in malignant transformation and proliferation. The aim of this study was to explore the clinical significance of ERCC1 and PKCα in non-small cell lung cancer (NSCLC). Methods The expression of ERCC1 and PKCα were examined by immunohistochemistry (IHC) in the specimens of 51 cases of NSCLC patients tissue and 21 cases of paracancerous tissue. The relationship between detected data and patients′ clinical parameters was analyzed by SPSS 13.0 software. Results The positive expression rate of ERCC1 and PKCα in NSCLC tissues was significantly higher than paracancerous tissues (Ρ<0.05). Expression of ERCC1 was closely related to clinical stage and N stage. The positive rate of ERCC1 was higher in III+IV or N1+N2 stage patients compared with I+II or N0 stage (Ρ=0.011, P=0.015). We also found that 5-year survival of negative group of ERCC1 was remarkably higher than that of positive group by χ2 test (Ρ<0.05). Expression of ERCC1 was positively correlative to PKCα by Spearman′s correlation analysis (r=0.425, P=0.002) in NSCLC. Conclusion The results suggest ERCC1 and PKCα might be correlated with the development of NSCLC. ERCC1 might be related to prognosis of NSCLC. There might be existed a mechanism of coordination or regulation between ERCC1 and PKCα

    Finite-Time Consensus of Networked Multiagent Systems with Time-Varying Linear Control Protocols

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    Finite-time consensus problems for networked multiagent systems with first-order/second-order dynamics are investigated in this paper. The goal of this paper is to design local information based control protocols such that the systems achieve consensus at any preset time. In order to realize this objective, a class of linear feedback control protocols with time-varying gains is introduced. We prove that the multiagent systems under such kinds of time-varying control protocols can achieve consensus at the preset time if the undirected communication graph is connected. Numerical simulations are presented to illustrate the effectiveness of the obtained theoretic results

    A reproducing kernel method for solving singularly perturbed delay parabolic partial differential equations

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    In this article, we put forward an efficient method on the foundation of a few reproducing kernel spaces(RK-spaces) and the collocation method to seek the solution of delay parabolic partial differential equations(PDEs) with singular perturbation. The approximated solution  to the equations is formulated and proved the exact solution is uniformly convergent by the solution. Furthermore, the partial differentiation of the approximated solution is also proved the partial derivatives of the exact solution is uniformly convergent by the solution. Meanwhile, we show that the accuracy of our method is in the order of T/n where T is the final time and n is the number of spatial (and time) discretization in the domain of interests. Three numerical examples are put forward to demonstrate the effectiveness of our presented scheme

    Glycosylphosphatidylinositol-Anchored Anti-HIV scFv Efficiently Protects CD4 T Cells from HIV-1 Infection and Deletion in hu-PBL Mice

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    ABSTRACT Despite success in viral inhibition and CD4 T cell recovery by highly active antiretroviral treatment (HAART), HIV-1 is still not curable due to the persistence of the HIV-1 reservoir during treatment. One patient with acute myeloid leukemia who received allogeneic hematopoietic stem cell transplantation from a homozygous CCR5 Δ32 donor has had no detectable viremia for 9 years after HAART cessation. This case has inspired a field of HIV-1 cure research focusing on engineering HIV-1 resistance in permissive cells. Here, we employed a glycosylphosphatidylinositol (GPI)-scFv X5 approach to confer resistance of human primary CD4 T cells to HIV-1. We showed that primary CD4 T cells expressing GPI-scFv X5 were resistant to CCR5 (R5)-, CXCR4 (X4)-, and dual-tropic HIV-1 and had a survival advantage compared to control cells ex vivo . In a hu-PBL mouse study, GPI-scFv X5-transduced CD4 T cells were selected in peripheral blood and lymphoid tissues upon HIV-1 infection. Finally, GPI-scFv X5-transduced CD4 T cells, after being cotransfused with HIV-infected cells, showed significantly reduced viral loads and viral RNA copy numbers relative to CD4 cells in hu-PBL mice compared to mice with GPI-scFv AB65-transduced CD4 T cells. We conclude that GPI-scFv X5-modified CD4 T cells could potentially be used as a genetic intervention against both R5- and X4-tropic HIV-1 infections. IMPORTANCE Blocking of HIV-1 entry is one of most promising approaches for therapy. Genetic disruption of the HIV-1 coreceptor CCR5 by nucleases in T cells is under 2 clinical trials and leads to reduced viremia in patients. However, the emergence of viruses using the CXCR4 coreceptor is a concern for therapies applying single-coreceptor disruption. Here, we report that HIV-1-permissive CD4 T cells engineered with GPI-scFv X5 are resistant to R5-, X4-, or dual-tropic virus infection ex vivo . In a preclinical study using hu-PBL mice, we show that CD4 T cells were protected and that GPI-scFv X5-transduced cells were selected in HIV-1-infected animals. Moreover, we show that GPI-scFv X5-transduced CD4 T cells exerted a negative effect on virus replication in vivo . We conclude that GPI-scFv X5-modified CD4 T cells could potentially be used as a genetic intervention against both R5- and X4-tropic HIV-1 infections

    Analysis of the genomic homologous recombination in Theilovirus based on complete genomes

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    At present, Theilovirus is considered to comprise four distinct serotypes, including Theiler's murine encephalomyelitis virus, Vilyuisk human encephalomyelitis virus, Thera virus, and Saffold virus. So far, there is no systematical study that investigated the genomic recombination of Theilovirus. The present study performed the phylogenetic and recombination analysis of Theilovirus over the complete genomes. Seven potentially significant recombination events were identified. However, according to the strains information and references related to the recombinants and their parental strains, four of the recombination events might happen non-naturally. These results will provide valuable hints for future research on evolution and antigenic variability of Theilovirus
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