39 research outputs found
Resource Allocation and Receiver Localization for Underlay CRs Using Interference Tweets
Cognitive radio network provides re-utilization of unused portions of the licensed spectrum. Such that primary users do not affect harmful interference from the transmission of secondary users. Therefore, to analyze the effect of interference across primary user and their minimization have become an important criterion in cognitive network. This paper attempts to provide localization technique based on Bayesian approach gives exact location of primary user. The conventional localization technique provides information related to coverage region of primary user so we cannot estimate accurate location. Secondary users opportunistically share a fixed spectrum resource with different probability of interference constraints. The proposed algorithm shows increased network utility with optimize performance of secondary network.
DOI: 10.17762/ijritcc2321-8169.15028
A Survey on Cyber Security for Smart Grid Networks
Smart grid is a electrical grid in which power generation units, transmission units, distribution units and electricity consumers are connected using advanced communication and information technologies. It is a new form of next generation power grid. Most of the countries across the globe are transforming their existing electrical grids to smart grid and hence smart grid technology is progressing worldwide. Smart grid provides a bi-directional flow of electricity and information from generation to transmission to distribution and hence more exposed to attacks. Many advanced communication technologies have been identified for smart grid usages. A secure communication infrastructure is a critical component of smart grid systems. Success of smart grids highly depends on secure communication network. Thus cyber security of smart grid networks is very important. In this paper, we summarize the cyber security threats, possible vulnerabilities and existing standards and solutions available for cyber security in smart grids networks based on the available reference material.
DOI: 10.17762/ijritcc2321-8169.15050
Performance Evaluation of Multiband OFDM and Pulsed OFDM using Matlab Simulation
Abstract In this paper, we describe a approach for reducing the power consumption and complexity of a multiband orthogonal frequency division multiplexing (MB-OFDM
Genetic programming assisted stochastic optimization strategies for optimization of glucose to gluconic acid fermentation
This article presents two hybrid strategies for the modeling and optimization of the glucose to gluconic acid batch bioprocess. In the hybrid approaches, first a novel artificial intelligence formalism, namely, genetic programming (GP), is used to develop a process model solely from the historic process input-output data. In the next step, the input space of the GP-based model, representing process operating conditions, is optimized using two stochastic optimization (SO) formalisms, viz., genetic algorithms (GAs) and simultaneous perturbation stochastic approximation (SPSA). These SO formalisms possess certain unique advantages over the commonly used gradient-based optimization techniques. The principal advantage of the GP-GA and GP-SPSA hybrid techniques is that process modeling and optimization can be performed exclusively from the process input-output data without invoking the detailed knowledge of the process phenomenology. The GP-GA and GP-SPSA techniques have been employed for modeling and optimization of the glucose to gluconic acid bioprocess, and the optimized process operating conditions obtained thereby have been compared with those obtained using two other hybrid modeling-optimization paradigms integrating artificial neural networks (ANNs) and GA/SPSA formalisms. Finally, the overall optimized operating conditions given by the GP-GA method, when verified experimentally resulted in a significant improvement in the gluconic acid yield. The hybrid strategies presented here are generic in nature and can be employed for modeling and optimization of a wide variety of batch and continuous bioprocesses
The Targeted SMAC Mimetic SW IV-134 is a strong enhancer of standard chemotherapy in pancreatic cancer
Abstract
Background
Pancreatic cancer is a lethal malignancy that frequently acquires resistance to conventional chemotherapies often associated with overexpression of inhibitors of apoptosis proteins (IAPs). We have recently described a novel means to deliver second mitochondria-derived activator of caspases (SMAC) mimetics selectively to cancer cells employing the sigma-2 ligand/receptor interaction. The intrinsic death pathway agonist SMAC offers an excellent opportunity to counteract the anti-apoptotic activity of IAPs. SMAC mimetics have been used to sensitize several cancer types to chemotherapeutic agents but cancer-selective delivery and appropriate cellular localization have not yet been considered. In our current study, we tested the ability of the sigma-2/SMAC drug conjugate SW IV-134 to sensitize pancreatic cancer cells to gemcitabine.
Methods
Using the targeted SMAC mimetic SW IV-134, inhibition of the X-linked inhibitor of apoptosis proteins (XIAP) was induced pharmacologically and its impact on cell viability was studied alone and in combination with gemcitabine. Pathway analyses were performed by assessing caspase activation, PARP cleavage and membrane blebbing (Annexin-V), key components of apoptotic cell death. Single-agent treatment regimens were compared with combination therapy in a preclinical mouse model of pancreatic cancer.
Results
The sensitizing effect of XIAP interference toward gemcitabine was confirmed via pharmacological intervention using our recently designed, targeted SMAC mimetic SW IV-134 across a wide range of commonly used pancreatic cancer cell lines at concentrations where the individual drugs showed only minimal activity. On a mechanistic level, we identified involvement of key components of the apoptosis machinery during cell death execution. Furthermore, combination therapy proved superior in decreasing the tumor burden and extending the lives of the animals in a preclinical mouse model of pancreatic cancer.
Conclusion
We believe that the strong sensitizing capacity of SW IV-134 in combination with clinically relevant doses of gemcitabine represents a promising treatment option that warrants clinical evaluation
Transcription factors and molecular epigenetic marks underlying EpCAM overexpression in ovarian cancer
BACKGROUND: The epithelial cell adhesion molecule (EpCAM) is overexpressed on carcinomas, and its downregulation inhibits the oncogenic potential of multiple tumour types. Here, we investigated underlying mechanisms of epcam overexpression in ovarian carcinoma. METHODS: Expression of EpCAM and DNA methylation (bisulphite sequencing) was determined for ovarian cancer cell lines. The association of histone modifications and 16 transcription factors with the epcam promoter was analysed by chromatin immunoprecipitation. Treatment with 5-Aza-2'-deoxycytidine (5-AZAC) was used to induce EpCAM expression. RESULTS: Expression of EpCAM was correlated with DNA methylation and histone modifications. Treatment with 5-AZAC induced EpCAM expression in negative cells. Ten transcription factors were associated with the epcam gene in EpCAM expressing cells, but not in EpCAM-negative cells. Methylation of an Sp1 probe inhibited the binding of nuclear extract proteins in electromobility shift assays; such DNA methylation sensitivity was not observed for an NF-kappa B probe. CONCLUSION: This study provides insights in transcriptional regulation of epcam in ovarian cancer. Epigenetic parameters associated with EpCAM overexpression are potentially reversible, allowing novel strategies for sustained silencing of EpCAM expression. British Journal of Cancer (2011) 105, 312-319. doi: 10.1038/bjc.2011.231 www.bjcancer.com Published online 21 June 2011 (C) 2011 Cancer Research U
Production of dextran by Rhizopus sp. immobilized on porous cellulose support
Mycelia from a culture of Rhizopus spp, isolated from soil, were immobilized on cellulose microfibrils support and used for bioconversion of sucrose to dextran. Both batch and continuous modes of operation were investigated. For immobilized mycelia in batch (shake flask) fermentation, dextran yield and specific rate of production were 14 g l-1 and 0.4 g g-1 h as compared to 11 g l-1 and 0.28 g g-1 h for free mycelia. In continuous fermentation, sucrose solution (45 g l-1) flows through the capillaries of the fabric support on which mycelia were pregrown, and is bioconverted at the interface to dextran. The system could be run continuously for a period of 25 days and the emerging broth showed higher yields of dextran presumably as a result of higher interface interactions between substrate and mycelia. The eluate contained 22 g l-1 of dextran, which was higher than expected as a result of evaporative concentration. Lignin in the medium is seen to be beneficial to both the final yield and specific rate of production. The effect of water activity on the bioconversion is described