On the Noisy Feedback Capacity of Gaussian Broadcast Channels

It is well known that, in general, feedback may enlarge the capacity region of Gaussian broadcast channels. This has been demonstrated even when the feedback is noisy (or partial-but-perfect) and only from one of the receivers. The only case known where feedback has been shown not to enlarge the capacity region is when the channel is physically degraded (El Gamal 1978, 1981). In this paper, we show that for a class of two-user Gaussian broadcast channels (not necessarily physically degraded), passively feeding back the stronger user's signal over a link corrupted by Gaussian noise does not enlarge the capacity region if the variance of feedback noise is above a certain threshold.Comment: 5 pages, 3 figures, to appear in IEEE Information Theory Workshop 2015, Jerusale

In silico analysis of c-Met expression and its correlation with metabolic network in head and neck cancer

Background: Head and Neck Squamous Cell Carcinoma (HNSCC) is strongly associated with metabolic dysregulations. c-Met activation is important for high glucose induced acquisition of mesenchymal phenotype, survival under high glucose stress in HNSCC cells. Here, we utilise the In silico approach to analyse the c-Met expression in the head and neck cancer data extracted from The Cancer Genome Atlas (TCGA) database and its strong correlation with genes associated with cancer cell metabolism. Methods: In the current study, our investigations were performed using different bioinformatics tools and databases, including GEPIA (a webserver which extracts data from the Cancer Genome Atlas (TCGA) data portal and the GTEx database of normal tissues. http://gepia.cancer-pku.cn), and STRING databases (functional protein association networks (https://string-db.org/). Results: Here, we report the upregulation of c-Met in HNSCC patient cases along with a significant upregulation of major metabolic genes such as GLUT-1, HK-II, LDH-A, MCT-1, PFK in the HNSCC patient cases as compared to normal samples obtained from TCGA databases. Moreover, the current study revealed the c-Met overexpression across the histological and molecular subtypes of different HNSCC patient cases. We also showed the possible association of c-Met expression between the metabolic gene expression in HNSCC patient samples. We showed that patients with higher expression of c-Met had a shorter overall survival time and worse prognosis, and c-Met higher-expression levels also resulted in worse disease free survival in many cancers, confirming the association of c-Met and metabolic related genes with poor clinical outcomes in HNSCC. Furthermore, the protein-protein network analysis identifies the co-expression of metabolic associated genes with the c-Met. Conclusions: Our analysis suggests the correlation with higher expression of c-Met with a shorter overall survival and worse prognosis of HNSCC patients. Furthermore, the proteinprotein network analysis identifies the co-expression of metabolic associated genes with the c-Met expression. Those genes with moderate and very strong positive correlations with cMet expression in cancers are involved in the glucose metabolism, lipid metabolism, cell cycle process. Considering c-Met inhibition in HNSCC would be an important strategy for therapy that may favour the sensitization of HNSCC through metabolic network

Biochemical Toxicology: Heavy Metals and Nanomaterials

The synthesis and application of nanoparticles have been actively studied in the modern era as it holds promises for effective and targeted strategies to deliver drugs inside the human body. Nanoparticles (NPs) play a big role in cancer diagnosis and have various advantages over other conventional chemotherapeutic drug delivery systems. But, the application of emerging engineered NPs to heavy toxic metals such as zinc, cobalt, and iron has resulted in a major source of toxicity. The toxicity of nanomaterials is majorly determined by their physical and chemical properties such as size, charge, and surface area. Also, the mechanism of nanotoxicity is majorly via the production of reactive oxygen species that create oxidative stress, thereby activating inflammatory cytokines and the mechanism of DNA damage that ultimately results in the cell death. So, mechanistic study needs to be done on nanomaterials to elucidate the mechanism involved in nanotoxicity and to generate less toxic and efficient nanomaterials

Prevalence of asthma in urban and rural children in Tamil Nadu

Background. There are very few community-based studies on the prevalence of asthma in Indian children. We aimed to estimate the prevalence of asthma in children under 12 years of age and to study possible differences in the prevalence of childhood asthma in urban and rural areas of Tamil Nadu. Methods. A total of 584 children from Chennai and 271 children from 25 villages around Chennai formed the urban and rural groups, respectively. From November 1999 to February 2000, data were collected using a simplified version of the ISAAC questionnaire, which was administered by trained students. Symptoms suggestive of asthma or hyperreactive airways disease in children under 12 years of age were recorded from the selected urban and rural populations by questioning the parents. The results were analysed separately for children 0-5 and 6-12 years of age. Results. Of the 855 children studied, the overall prevalence of breathing difficulty (including asthma) was 18% and the prevalence of ‘diagnosed’ asthma was 5%. Twenty-two per cent of urban and 9% of rural children 6-12 years of age reported breathing difficulty ‘at any time in the past’ (p<0.01). A significantly higher proportion of 6-12-year-old urban children also reported nocturnal dry cough (28.4%v. 18.7%,p<0.05). Urban children reported recent wheeze more often than rural children (92% v. 77%, p=0.01). Conclusions. Symptoms suggestive of asthma were present in 18% of children under 12 years of age. Though the prevalence of diagnosed childhood asthma was about 5% in both urban and rural areas, the prevalence of ‘breathing difficulty’ and nocturnal cough was significantly higher among urban children in the age group of 6-12 years. Children living in urban areas also reported ‘recent wheeze’ more often than rural children. Our data suggest that the actual prevalence of asthma and other ‘wheezy’ illnesses may be higher than that previously documented. Further studies are needed to confirm the difference in prevalence between urban and rural children and also to identify possible causes that could account for the higher urban prevalence of asthma in Tamil Nadu

Optimal WiFi Sensing via Dynamic Programming

The problem of finding an optimal sensing schedule for a mobile device that encounters an intermittent WiFi access opportunity is considered. At any given time, the WiFi is in any of the two modes, ON or OFF, and the mobile's incentive is to connect to the WiFi in the ON mode as soon as possible, while spending as little sensing energy. We introduce a dynamic programming framework which enables the characterization of an explicit solution for several models, particularly when the OFF periods are exponentially distributed. While the problem for non-exponential OFF periods is ill-posed in general, a usual workaround in literature is to make the mobile device aware if one ON period is completely missed. In this restricted setting, using the DP framework, the deterministic nature of the optimal sensing policy is established, and value iterations are shown to converge to the optimal solution. Finally, we address the blind situation where the distributions of ON and OFF periods are unknown. A continuous bandit based learning algorithm that has vanishing regret (loss compared to the optimal strategy with the knowledge of distributions) is presented, and comparisons with the optimal schemes are provided for exponential ON and OFF times