Thermoelectric properties of topological chains coupled to a quantum dot.

Topological one-dimensional superconductors can sustain zero energy modes protected by different kinds of symmetries in their extremities. Observing these excitations in the form of Majorana fermions is one of the most intensive quests in condensed matter physics. We are interested in another class of one-dimensional topological systems in this work, namely topological insulators. Which present symmetry-protected end modes with robust properties and do not require the low temperatures necessary for topological superconductivity. We consider a device in the form of a single electron transistor coupled to the simplest kind of topological insulators, namely chains of atoms with hybridized sp orbitals. We study the thermoelectric properties of the device in the trivial, non-trivial topological phases and at the quantum topological transition of the chains. We show that the device's electrical conductance and the Wiedemann-Franz ratio at the topological transition have universal values at very low temperatures. The conductance and thermopower of the device with diatomic sp-chains, at their topological transition, give direct evidence of fractional charges in the system. The former has an anomalous low-temperature behavior, attaining a universal value that is a consequence of the double degeneracy of the system due to the presence of zero energy modes. On the other hand, the system can be tuned to exhibit high values of the thermoelectric figure of merit and the power factor at high temperatures.

Treadmill exercise testing of asymptomatic men and women without evidence of heart disease

The aim of this study was to test the hypothesis of differences in performance including differences in ST-T wave changes between healthy men and women submitted to an exercise stress test. Two hundred (45.4 percent) men and 241 (54.6 percent) women (mean age: 38.7 ¡À 11.0 years) were submitted to an exercise stress test. Physiologic and electrocardiographic variables were compared by the Student t-test and the chi-square test. To test the hypothesis of differences in ST-segment changes, data were ranked with functional models based on weighted least squares. To evaluate the influence of gender and age on the diagnosis of ST-segment abnormality, a logistic model was adjusted; P < 0.05 was considered to be significant. Rate-pressure product, duration of exercise and estimated functional capacity were higher in men (P < 0.05). Sixteen (6.7 percent) women and 9 (4.5 percent) men demonstrated ST-segment upslope ¡Ý0.15 mV or downslope ¡Ý0.10 mV; the difference was not statistically significant. Age increase of one year added 4 percent to the chance of upsloping of segment ST ¡Ý0.15 mV or downsloping of segment ST ¡Ý0.1 mV (P = 0.03; risk ratio = 1.040, 95 percent confidence interval (CI) = 1.002-1.080). Heart rate recovery was higher in women (P < 0.05). The chance of women showing an increase of systolic blood pressure ¡Ü30 mmHg was 85 percent higher (P = 0.01; risk ratio = 1.85, 95 percentCI = 1.1-3.05). No significant difference in the frequency of ST-T wave changes was observed between men and women. Other differences may be related to different physical conditioning.

Treadmill exercise testing of asymptomatic men and women without evidence of heart disease.

The aim of this study was to test the hypothesis of differences in performance including differences in ST-T wave changes between healthy men and women submitted to an exercise stress test. Two hundred (45.4%) men and 241 (54.6%) women (mean age: 38.7 +/- 11.0 years) were submitted to an exercise stress test. Physiologic and electrocardiographic variables were compared by the Student t-test and the chi-square test. To test the hypothesis of differences in ST-segment changes, data were ranked with functional models based on weighted least squares. To evaluate the influence of gender and age on the diagnosis of ST-segment abnormality, a logistic model was adjusted; P < 0.05 was considered to be significant. Rate-pressure product, duration of exercise and estimated functional capacity were higher in men (P < 0.05). Sixteen (6.7%) women and 9 (4.5%) men demonstrated ST-segment upslope >or=0.15 mV or downslope >or=0.10 mV; the difference was not statistically significant. Age increase of one year added 4% to the chance of upsloping of segment ST >or=0.15 mV or downsloping of segment ST >or=0.1 mV (P = 0.03; risk ratio = 1.040, 95% confidence interval (CI) = 1.002-1.080). Heart rate recovery was higher in women (P < 0.05). The chance of women showing an increase of systolic blood pressure

Association of HDL cholesterol and triglycerides with mortality in patients with heart failure

It has been demonstrated that there is an association between serum lipoproteins and survival rate in patients with ischemic cardiomyopathy, as well as in patients with non-ischemic causes of heart failure. We tested the hypothesis of an association between serum lipoprotein levels and prognosis in a cohort of outpatients with heart failure, including Chagas' heart disease. The lipid profile of 833 outpatients with heart failure in functional classes III and IV of the New York Heart Association, with a mean age of 46.9 ± 10.6 years, 655 (78.6 percent) men and 178 (21.4 percent) women, was studied from April 1991 to June 2003. The survival rate was estimated by the Kaplan-Meyer's method and the Cox proportional hazards models. Etiology of heart failure was ischemic cardiomyopathy in 171 (21 percent) patients, Chagas' heart disease in 144 (17 percent), hypertensive cardiomyopathy in 136 (16 percent), and other etiologies in 83 (10 percent). In 299 (36 percent) patients, heart failure was ascribed to idiopathic dilated cardiomyopathy. Variables significantly associated with mortality were age (hazard ratio, HR = 1.02; 95 percentCI = 1.01-1.03; P = 0.0074), male gender (HR = 1.77; 95 percentCI = 1.2-2.62; P = 0.004), idiopathic dilated cardiomyopathy (HR = 1.81; 95 percentCI = 1.16-2.82; P = 0.0085), serum triglycerides (HR = 0.97; 95 percentCI = 0.96-0.98; P < 0.0001), and HDL cholesterol (HR = 0.99; 95 percentCI = 0.99-1.0; P = 0.0280). Therefore, higher serum HDL cholesterol and higher serum triglycerides were associated with lower mortality in this cohort of outpatients with heart failure.

Association of HDL cholesterol and triglycerides with mortality in patients with heart failure.

It has been demonstrated that there is an association between serum lipoproteins and survival rate in patients with ischemic cardiomyopathy, as well as in patients with non-ischemic causes of heart failure. We tested the hypothesis of an association between serum lipoprotein levels and prognosis in a cohort of outpatients with heart failure, including Chagas' heart disease. The lipid profile of 833 outpatients with heart failure in functional classes III and IV of the New York Heart Association, with a mean age of 46.9 +/- 10.6 years, 655 (78.6%) men and 178 (21.4%) women, was studied from April 1991 to June 2003. The survival rate was estimated by the Kaplan-Meyer's method and the Cox proportional hazards models. Etiology of heart failure was ischemic cardiomyopathy in 171 (21%) patients, Chagas' heart disease in 144 (17%), hypertensive cardiomyopathy in 136 (16%), and other etiologies in 83 (10%). In 299 (36%) patients, heart failure was ascribed to idiopathic dilated cardiomyopathy. Variables significantly associated with mortality were age (hazard ratio, HR = 1.02; 95%CI = 1.01-1.03; P = 0.0074), male gender (HR = 1.77; 95%CI = 1.2-2.62; P = 0.004), idiopathic dilated cardiomyopathy (HR = 1.81; 95%CI = 1.16-2.82; P = 0.0085), serum triglycerides (HR = 0.97; 95%CI = 0.96-0.98; P < 0.0001), and HDL cholesterol (HR = 0.99; 95%CI = 0.99-1.0; P = 0.0280). Therefore, higher serum HDL cholesterol and higher serum triglycerides were associated with lower mortality in this cohort of outpatients with heart failure.

Aplicaçäo de Metildigorcina, alfa-e-Acetildigoxina em cäes sadios: concentraçöes séricas, período de meia-vida e efeitos sobre o eletrocardiograma / Methyl-, alfa-and B-acetyl-digoxin administration in healthy dogs: blood levels, half-life and effect on the electrocardiogram

A aplicaçäo de derivados de digoxina em cäes forneceu concentraçöes séricas médias, no platô, de 1,43ng/ml para metildigoxina e de 1,08 a 1,02ng/ml para B- e alfa-acetildigoxina, respectivamente. O período de meia-vida sérica foi de 53,6 h para o metilderivado, de 21,5h e de 23,4h, respectivamente, para os acetilderivados alfa e B. Alteraçöes eletrocardiográficas limitaram-se ao prolongamento do intervalo PQ, quando os níveis séricos mantiveram-se nos limites terapêuticos. Bloqueio atrioventricular de primeiro grau e inversäo de ondas T ocorrem em animais com concentraçöes digitálicas superiores a 0,2 ng/ml