On C*-algebras generated by pairs of q-commuting isometries

We consider the C*-algebras O_2^q and A_2^q generated, respectively, by isometries s_1, s_2 satisfying the relation s_1^* s_2 = q s_2 s_1^* with |q| < 1 (the deformed Cuntz relation), and by isometries s_1, s_2 satisfying the relation s_2 s_1 = q s_1 s_2 with |q| = 1. We show that O_2^q is isomorphic to the Cuntz-Toeplitz C*-algebra O_2^0 for any |q| < 1. We further prove that A_2^{q_1} is isomorphic to A_2^{q_2} if and only if either q_1 = q_2 or q_1 = complex conjugate of q_2. In the second part of our paper, we discuss the complexity of the representation theory of A_2^q. We show that A_2^q is *-wild for any q in the circle |q| = 1, and hence that A_2^q is not nuclear for any q in the circle.Comment: 18 pages, LaTeX2e "article" document class; submitted. V2 clarifies the relationships between the various deformation systems treate

MRC chronic Dyspnea Scale: Relationships with cardiopulmonary exercise testing and 6-minute walk test in idiopathic pulmonary fibrosis patients: a prospective study

<p>Abstract</p> <p>Background</p> <p>Exertional dyspnea is the most prominent and disabling feature in idiopathic pulmonary fibrosis (IPF). The Medical Research Chronic (MRC) chronic dyspnea score as well as physiological measurements obtained during cardiopulmonary exercise testing (CPET) and the 6-minute walk test (6MWT) are shown to provide information on the severity and survival of disease.</p> <p>Methods</p> <p>We prospectively recruited IPF patients and examined the relationship between the MRC score and either CPET or 6MWT parameters known to reflect physiologic derangements limiting exercise capacity in IPF patients</p> <p>Results</p> <p>Twenty-five patients with IPF were included in the study. Significant correlations were found between the MRC score and the distance (r = -.781, p < 0.001), the SPO₂at the initiation and the end (r = -.542, p = 0.005 and r = -.713, p < 0.001 respectively) and the desaturation index (r = .634, p = 0.001) for the 6MWT; the MRC score and <it>V</it>O₂peak/kg (r = -.731, p < 0.001), SPO₂at peak exercise (r = -. 682, p < 0.001), VE/VCO₂slope (r = .731, p < 0.001), VE/VCO₂at AT (r = .630, p = 0.002) and the Borg scale at peak exercise (r = .50, p = 0.01) for the CPET. In multiple logistic regression analysis, the only variable independently related to the MRC is the distance walked at the 6MWT.</p> <p>Conclusion</p> <p>In this population of IPF patients a good correlation was found between the MRC chronic dyspnoea score and physiological parameters obtained during maximal and submaximal exercise testing known to reflect ventilatory impairment and exercise limitation as well as disease severity and survival. This finding is described for the first time in the literature in this group of patients as far as we know and could explain why a simple chronic dyspnea score provides reliable prognostic information on IPF.</p

Losartan controlled blood pressure and reduced left ventricular hypertrophy but did not alter arrhythmias in hypertensive men with preserved systolic function

The effect of antihypertensive therapy on arrhythmias is controversial. An initial study in patients with chronic heart failure indicated that losartan, an angiotensin 11 receptor antagonist, may possess antiarrhythmic properties. However, the effect of AT1 receptor antagonists on arrhythmias of subjects with good systolic function has never been evaluated. Thirty-nine men with primary hypertension (18 without left ventricular hypertrophy [LVH], and 21 with LVH, aged 48.2 +/- 8.6 and 50.5 +/- 6.0 years, respectively), 15 healthy normotensive subjects (47.9 +/- 8.5 years), and 14 highly trained athletes (34.1 +/- 1.6 years) were studied. Transthoracic echocardiography and 24-hour Holter ambulatory monitoring were performed at baseline (without treatment). Hypertensive patients underwent the same examinations after 8 months of losartan administration. The prevalence and complexity of ventricular arrhythmias, and the frequency of supraventricular arrhythmias were increased in hypertensive patients with LVH compared to normotensive controls and athletes, at baseline. A similar significant reduction of blood pressure (BID) was noted in both groups of patients (p &lt; 0,001). The LVH was reduced in hypertensives with LVH (the left ventricular mass index by 12%, the interventricular septum by 8.1%, the posterior wall by 7%, all p &lt; 0.01). However, the arrhythmias did not change in either group of patients, even if all hypertensives were considered as 1 group. In conclusion, an 8-month course with losartan was effective in lowering BP and reducing LVH. However, the increased arrhythmias, which were registered in hypertensive patients with LVH at baseline, did not change

FePt clusters synthesized by thermal pyrolysis of Fe and Pt compounds in an organic solvent

A simple synthetic procedure involving the pyrolysis of Fe and Pt acetylacetonates mixed in trioctylamine results in the formation of alloy clusters with an average cluster around 4.2 nm and narrow size distribution. When the clusters are dispersed onto silicon wafers and heated under the protection of forming gas or nitrogen, the fcc structured clusters transform into hard magnetic FePt clusters with L10 chemical order. Coercivity values as high as 23 kOe are reached after rapid thermal annealing at 750 °C for 5 min

Unilateral pulmonary edema due to pulmonary venous obstruction from fibrosing mediastinitis

An unusual case of fibrosing mediastinitis with obstruction of the inferior and superior left pulmonary veins and severe narrowing of the right pulmonary artery, disclosed after unilateral pulmonary edema, is described. The 18-year-old male patient had a long history of cough, progressive dyspnea and recurrent hemoptysis and the possible diagnosis of "interstitial fibrosis" from a previous lung biopsy. The diagnosis and the pulmonary vessels involvement were suspected after right heart catheterization combined with transesophageal echocardiography and confirmed during urgent thoracotomy and at postmortem examination. (c) 2005 Elsevier Ireland Ltd. All rights reserved

Unilateral pulmonary edema due to pulmonary venous obstruction from fibrosing mediastinitis

An unusual case of fibrosing mediastinitis with obstruction of the inferior and superior left pulmonary veins and severe narrowing of the right pulmonary artery, disclosed after unilateral pulmonary edema, is described. The 18-year-old male patient had a long history of cough, progressive dyspnea and recurrent hemoptysis and the possible diagnosis of “interstitial fibrosis” from a previous lung biopsy. The diagnosis and the pulmonary vessels involvement were suspected after right heart catheterization combined with transesophageal echocardiography and confirmed during urgent thoracotomy and at postmortem examination. (c) 2005 Elsevier Ireland Ltd. All rights reserved