• Journal of Communications and Networks
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• v.18 no.3
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• pp.311-319
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• 2016

In this paper, we analyze the spectrum-sensing performance of a cooperative cognitive radio (CR) network consisting of a number of CR nodes and a fusion center (FC). We introduce the "log-average-SNR ratio" that relates the average SNR of the CR-node-FC link and that of the primary-user-CR-node link. Assuming that the FC utilizes the K-out-of-N rule as its decision rule, we derive exact expressions for the sensing gain and the coding gain - parameters used to characterize the CR network performance at the high SNR region. Based on these results, we determine ways to optimize the performance of the CR network.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3302-3320
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• 2014

An allocation of sensing and reporting times is proposed to improve the sensing performance by scheduling them in an efficient way for cognitive radio networks with cluster-based cooperative spectrum sensing. In the conventional cooperative sensing scheme, all secondary users (SUs) detect the primary user (PU) signal to check the availability of the spectrum during a fixed sensing time slot. The sensing results from the SUs are reported to cluster heads (CHs) during the reporting time slots of the SUs and the CHs forward them to a fusion center (FC) during the reporting time slots of the CHs through the common control channels for the global decision, respectively. However, the delivery of the local decision from SUs and CHs to a CH and FC requires a time which does not contribute to the performance of spectrum sensing and system throughput. In this paper, a super-allocation technique, which merges reporting time slots of SUs and CHs to sensing time slots of SUs by re-scheduling the reporting time slots, has been proposed to sense the spectrum more accurately. In this regard, SUs in each cluster can obtain a longer sensing duration depending on their reporting order and their clusters except for the first SU belonged to the first cluster. The proposed scheme, therefore, can achieve better sensing performance under -28 dB to -10 dB environments and will thus reduce reporting overhead.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.8
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• pp.761-767
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• 2011

In this paper, to improve performance of spectrum sensing, we propose the method which can find optimal threshold based on power of PU(Primary User) signal. To find optimal threshold value, we will use mathematical method, and find threshold which can has lowest error probability. Each SU(Secondary User) use this threshold and All Su makes local decision. All Su Send local decision to FC(Fusion Center). In this paper we consider K-out-of-n rule to combining local decision. To make global decision value, FC find optimal n. In the FC. FC received local decision which has lowest error probability and using optimal n and these vaule. FC make global decision value. In this paper, to analysis performance proposed scheme, we simulate proposed scheme using matlab and compare with traditional OR Rule. As a result of simulation, we can know that preposed scheme can get a better performance than traditional OR rule.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.568-576
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• 2014

TIM-1 (also known as KIM-1 and HAVcr-1) is a type I transmembrane glycoprotein member of the TIM family that may play important roles in innate and adaptive immune responses. The overexpression of proteins associated with membrane proteins is a major obstacle to overcome in studies of membrane protein structures and functions. In this study, we successfully coupled the overexpression of the TIM-1 protein with a C-terminal enhanced green fluorescent protein (GFP) tag in Escherichia coli. To the best of our knowledge, this report is the first to describe the overexpression of human TIM-1 in E. coli. The purified TIM-1-EGFP fusion protein recognized and bound directly to apoptotic cells and did not to bind to viable cells. Furthermore, we confirmed that the interactions of TIM-1-EGFP with apoptotic cells were blocked by TIM-1-Fc fusion proteins. This fusion protein represents a readily obtainable source of biologically active TIM-1 that may prove useful in future studies of human TIM-1.

• Clinical and Experimental Pediatrics
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• v.54 no.9
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• pp.373-379
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• 2011

Purpose: 4-1BB (CD 137) is a costimulatory molecule expressed on activated T-cells. Repression by 4-1BB is thought to attenuate Th2-mediated allergic reactions. The aim of this study was to investigate the effect of 4-1BB on allergic airway inflammation in a murine asthma model. Methods: BALB/c mice were sensitized to and challenged with ovalbumin (OVA). Hu.4-1BB-Fc was administered 1 day before the first OVA sensitization or 1 day after the second OVA sensitization. Following antigen challenge, airway responsiveness to methacholine was assessed and bronchoalveolar lavage (BAL) fluid was analyzed. Total immunoglobulin (Ig) E, OVA-specific IgE, $IgG_1$, and $IgG_{2a}$ levels in sera were measured by enzyme-linked immunosorbent assay. Lung pathology was also evaluated. Results: In mice treated with Hu.4-1BB-Fc before the first OVA sensitization, there was a marked decrease in airway hyperresponsiveness, total cell count, and eosinophil count in the BAL fluid. In addition, Hu.4-1BB-Fc treatment decreased serum OVA-specific $IgG_1$ levels and increased serum $IgG_{2a}$ level significantly compared with the corresponding levels in mice sensitized to and challenged with OVA. Hu.4-1BB-Fc-treated mice also showed suppressed peribronchial and perivascular inflammatory cell infiltration. In contrast, treatment with Hu.4-1BB-Fc 1 day after sensitization had no effect on airway hyperresponsiveness and showed less suppression of inflammation in lung tissue. Conclusion: Administration of Hu.4-1BB-Fc can attenuate airway inflammation and hyperreactivity in a mouse model of allergic airway inflammation. In addition, administration before sensitization may be more effective. These findings suggest that 4-1BB may be a useful therapeutic molecule against asthma.

• IMMUNE NETWORK
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• v.13 no.4
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• pp.148-156
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• 2013

The $PrP^C$ is expressed in many types of immune cells including monocytes and macrophages, however, its function in immune regulation remains to be elucidated. In the present study, we examined a role for $PrP^C$ in regulation of monocyte function. Specifically, the effect of a soluble form of $PrP^C$ was studied in human monocytes. A recombinant fusion protein of soluble human $PrP^C$ fused with the Fc portion of human IgG1 (designated as soluble $PrP^C$-Fc) bound to the cell surface of monocytes, induced differentiation to macrophage-like cells, and enhanced adherence and phagocytic activity. In addition, soluble $PrP^C$-Fc stimulated monocytes to produce pro-inflammatory cytokines such as $TNF-{\alpha}$, $IL-1{\beta}$, and IL-6. Both ERK and $NF-{\kappa}B$ signaling pathways were activated in soluble $PrP^C$-treated monocytes, and inhibitors of either pathway abrogated monocyte adherence and cytokine production. Taken together, we conclude that soluble $PrP^C$-Fc enhanced adherence, phagocytosis, and cytokine production of monocytes via activation of the ERK and $NF-{\kappa}B$ signaling pathways.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.3
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• pp.781-784
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• 2012

The aim of this study was to evaluate the effect of the adenovirus-mediated double suicide gene (CD/TK) for selective killing of gastric cancer cells. Gastric cancer cells SCG7901 and normal gastric epithelial cell lines were infected by adenoviruses Ad-survivin/GFP and Ad-survivin/CD/TK. GFP expression and CD-TK were detected by fluorescence microscopy and reverse transcriptase polymerase chain reaction (RT-PCR), respectively. After treatment of the infected cells with the pro-drugs ganciclovir (GCV) and/or 5-FC, the cell growth status was evaluated by methyl thiazolyl tetrazolium assay. Cell cycle changes were detected using flow cytometry. In nude mice bearing human gastric cancer, the recombinant adenovirus vector was injected directly into the tumor followed by an intraperitoneal injection of GCV and/or 5-FC. The subsequent tumor growth was then observed. The GFP gene driven by survivin could be expressed within the gastric cancer line SCG7901, but not in normal gastric epithelial cells. RT-PCR demonstrated the presence of the CD/TK gene product in the infected SCG7901 cells, but not in the infected normal gastric epithelial cells. The infected gastric cancer SCG7901, but not the gastric cells, was highly sensitive to the pro-drugs. The CD/TK fusion gene system showed significantly greater efficiency than either of the single suicide genes in killing the target cells (P<0.01). Treatment of the infected cells with the pro-drugs resulted in increased cell percentage in G0-Gl phase and decreased percentage in S phase. In nude mice bearing SCG7901 cells, treatment with the double suicide gene system significantly inhibited tumor growth, showing much stronger effects than either of the single suicide genes (P<0.01). The adenovirus-mediated CD/TK double suicide gene driven by survivin promoter combined with GCV an 5-FC treatment could be an effective therapy against experimental gastric cancer with much greater efficacy than the single suicide gene CD/TK combined with GCV or 5-FC.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup1
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• pp.13-19
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• 2001

Objective : We investigated the feasibility of a double suicide gene/prodrug therapy, involving direct introduction of the herpes simplex virus Type 1 thymidine kinase(TK) gene and the Escherichia coli cytosine deaminase(CD) gene, via a recombinant adenoviral vector and ganciclovir(GCV) and/or 5-fluorocytosine(5-FC) treatment, in C6 glioma cells. Methods : Efficient gene transfer and transduction of C6 glioma cells via a recombinant adenovirus were evaluated by infecting cells with adenovirus bearing the ${\beta}$-galactosidase gene and then staining cells with 5-bromo-4-chloro-3-indolyl-13-D-galactoside. CD/TK expression in cells infected with adenovirus bearing the CD/TK gene(ad-CD/TK) was examined by immunoblotting analysis. For in vitro cytotoxicity experiments, the cells were infected with ad-CD/TK or ad-${\Delta}E1$(as a control). After addition of a variety of concentrations of GCV and 5-FU, either separately or in combination, cell viability was determined by staining the cells with crystal violet solution 6 days after infection. Result : C6 glioma cells were efficiently transduced with recombinant adenoviral vector at multiplicities of infection of 200 or more. In vitro cytotoxicity of GCV and/or 5-FC, either alone or in combination, was exclusively observed in the cells transduced with ad-CD/TK. Obvious cytotoxicity(>50% inhibition) was observed in the presence of 5-FC at concentrations greater than 30ug/ml or GCV at concentrations greater than 0.3ug/ml at a multiplicity of infection of 100. Additionally, cytotoxicity in the presence of both GCV and 5-FC was greater than that after sinlge-prodrug treatments, indicating additive effects of the prodrug treatments. Conclusion : The administration of a double-suicide gene/prodrug therapy might have great potential in the treatment of brain tumors.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2471-2474
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• 2009

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.1
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• pp.19-27
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• 2014

As frequency resource has taken on greater importance, Cognitive Radio(CR) technology has been considered as the solution to improve spectrum utilization by allowing a secondary user to utilize a licensed band when the primary user is absent. So spectrum sensing is significant part of CR for high performance. Recently, cooperative spectrum sensing that secondary users share each sensing results is proposed to improve spectrum sensing accuracy. In this paper, OR rule based cooperative spectrum sensing scheme using reporting error probability which occurs in user to fusion center(FC) channel The simulation results show that proposed scheme mitigates false alarm probability limitation which appears in existing cooperative spectrum sensing scheme by restricting the number of cooperating users using reporting error probability.