Kullback-Leibler Divergence-Guided Copula Statistics-Based Blind Source Separation of Dependent Signals

In this paper, we propose a blind source separation of a linear mixture of dependent sources based on copula statistics that measure the non-linear dependence between source component signals structured as copula density functions. The source signals are assumed to be stationary. The method minimizes the Kullback-Leibler divergence between the copula density functions of the estimated sources and of the dependency structure. The proposed method is applied to data obtained from the time-domain analysis of the classical 11-Bus 4-Machine system. Extensive simulation results demonstrate that the proposed method based on copula statistics converges faster and outperforms the state-of-the-art blind source separation method for dependent sources in terms of interference-to-signal ratio.Comment: Submitted to the ISGT NA 202

Apolipoprotein gene polymorphisms and plasma levels in healthy Tunisians and patients with coronary artery disease

<p>Abstract</p> <p>Aim</p> <p>To analyze apolipoprotein gene polymorphisms in the Tunisian population and to check the relation of these polymorphisms and homocysteine, lipid and apolipoprotein levels to the coronary artery disease (CAD).</p> <p>Methods</p> <p>In healthy blood donors and in patients with CAD complicated by myocardial infarction (MI) four apolipoprotein gene polymorphisms [APO (a) PNR, APO E, APO CI and APO CII] were determined and plasma levels of total homocysteine, total cholesterol (TC), triglycerides (TG), HDL-cholesterol (HLD-C) and apolipoproteins (apo A-I, Apo B, Apo E) were measured.</p> <p>Results</p> <p>Analysis of the four apolipoprotein gene polymorphisms shows a relative genetic homogeneity between Tunisian population and those on the other side of Mediterranean basin. Compared to controls, CAD patients have significantly higher main concentrations of TC, TG, LDL-C, apo B and homocysteine, and significantly lower ones of HDL-C, apo A-I and apo E. The four apolipoprotein gene polymorphisms have not showed any significant differences between patients and controls. However, the APO E4 allele appears to be associated to the severity of CAD and to high levels of atherogenic parameters and low level of apo E, which has very likely an anti-atherogenic role.</p> <p>Conclusion</p> <p>Although APO (a) PNR, APO CI and APO CII genes are analyzed in only few populations, they show a frequency distribution, which is not at variance with that of APO E gene and other widely studied genetic markers. In the Tunisian population the APO E 4 appears to be only indirectly involved in the severity of CAD. In the routine practice, in addition of classic parameters, it will be useful to measure the concentration of apo E and that of Homocysteine and if possible to determine the APO E gene polymorphism.</p

Combined Analysis of EPHX1, GSTP1, GSTM1 and GSTT1 Gene Polymorphisms in Relation to Chronic Obstructive Pulmonary Disease Risk and Lung Function Impairment

Smoking is considered as the major causal factor of chronic obstructive pulmonary disease (COPD). Nevertheless, a minority of chronic heavy cigarette smokers develops COPD. This suggests important contribution of other factors such as genetic predisposing. Our objective was to investigate combined role of EPHX1, GSTP1, M1 and T1 gene polymorphisms in COPD risk, its phenotypes and lung function impairment. Prevalence of EPHX1, GSTP1, M1 and T1 gene polymorphisms were assessed in 234 COPD patients and 182 healthy controls from Tunisia. Genotypes of EPHX1 (Tyr113His; His139Arg) and GSTP1 (Ile105Val; Ala114Val) polymorphisms were performed by PCR-RFLP, while the deletion in GSTM1 and GSTT1 genes was determined using multiplex PCR. Analysis of combinations showed a significant association of 113His/His EPHX1/null-GSTM1 (OR = 4.07) and null-GSTM1/105Val/Val GSTP1 (OR = 3.56) genotypes with increased risk of COPD (respectively P=0.0094 and P=0.0153). The null-GSTM1/ null-GSTT1, 105Val/Val GSTP1/null GSTT1, 113His/His EPHX1/null-GSTM1 and null-GSTM1/105Val/Val GSTP1 genotypes were related to emphysema (respectively P = 0.01; P = 0.009; P = 0.008 and P = 0.001). Combination of 113His/His EPHX1/null-GSTM1 genotypes showed a significant association with the decrease of ΔFEV1 in patients (P = 0.028)

Indoleamine 2,3‐dioxygenase gene expression and kynurenine to tryptophan ratio correlation with nasopharyngeal carcinoma progression and survival

Abstract Introduction Indoleamine 2,3‐dioxygenase (IDO) is an immunosuppressive tryptophan‐depleting enzyme expressed in nasopharyngeal carcinoma (NPC) tissue. However, IDO has not been reported in the peripheral blood of NPC patients. The aim of this study was to analyze, IDO1 and IDO2 messenger RNA (mRNA) expression, the kynurenine (Kyn) and tryptophan (Trp) plasma levels, their clinical values and their relationship with cytokine levels in NPC. Methods We evaluated IDO1 and IDO2 mRNA expression in peripheral blood mononuclear cells (PBMC) by quantitative real‐time PCR, plasma Trp and Kyn levels by HPLC, and cytokine levels by ELISA in 75 NPC patients and 51 healthy controls. Results Compared to controls, IDO1 mRNA expression was significantly upregulated and IDO2 mRNA expression was significantly downregulated in PBMC of patients. Also compared to controls, plasma Kyn levels and Kyn/Trp ratio were significantly higher in patients. At the time of diagnosis, the plasma Kyn/Trp ratio was associated with advanced cancer status and was an independent prognostic factor for worse disease‐specific survival. According to cancer stages, IDO1 mRNA expression was positively correlated with plasma Kyn/Trp ratio in patients with earlier stages (I–II–III) but negatively correlated in patients with the late‐stage cancer (IV). Tumor necrosis factor‐α, interleukin (IL)‐6 and IL‐10 levels were significantly higher in patients compared to controls. Moreover, and despite treatment, patients simultaneously carrying high plasma Kyn/Trp ratio and high plasma IL‐6 and IL‐10 levels at diagnosis died approximately 1 year after first diagnosis. Conclusion Measuring blood IDO mRNA expression and Kyn/Trp ratio at diagnosis could be a potential marker to evaluate NPC progression and predict survival outcome