594 research outputs found

    TOSC: an algorithm for the tomography of spotted transit chords

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    Photometric observations of planetary transits may show localized bumps, called transit anomalies, due to the possible crossing of photospheric starspots. The aim of this work is to analyze the transit anomalies and derive the temperature profile inside the transit belt along the transit direction. We develop the algorithm TOSC, a tomographic inverse-approach tool which, by means of simple algebra, reconstructs the flux distribution along the transit belt. We test TOSC against some simulated scenarios. We find that TOSC provides robust results for light curves with photometric accuracies better than 1~mmag, returning the spot-photosphere temperature contrast with an accuracy better than 100~K. TOSC is also robust against the presence of unocculted spots, provided that the apparent planetary radius given by the fit of the transit light curve is used in place of the true radius. The analysis of real data with TOSC returns results consistent with previous studies

    Diagnostic Approach to Patients with Stable Angina and No Obstructive Coronary Arteries

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    The diagnosis of microvascular angina (MVA) is usually considered in patients presenting with angina symptoms and evidence of MI on non-invasive stress tests but normal coronary arteries at angiography. A definitive diagnosis of MVA, however, would require the presence of coronary microvascular dysfunction. Several invasive (e.g. intracoronary Doppler wire recording and thermodilution) and non-invasive (e.g. PET, cardiac MRI, transthoracic Doppler echocardiography) methods can be applied to obtain a diagnosis. Both endothelium- dependent and -independent coronary microvascular dilator function, as well as increased microvascular constrictor activity, should be investigated. The main issues in the assessment of clinical and diagnostic findings in patients with suspected MVA are discussed and a diagnostic approach is suggested

    Management of Coronary Artery Spasm

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    Calcium channel blockers (CCBs) are the first-line treatment for coronary artery spasm (CAS). When CAS-related angina symptoms are not well controlled by CCB therapy, long-acting nitrates or (where available) nicorandil can be added as second-line medications. In the case of CAS refractory to standard treatments, several other alternative drugs and interventions have been proposed, including the Rho-kinase inhibitor fasudil, anti-adrenergic drugs, neural therapies and percutaneous coronary interventions. In patients with syncope or cardiac arrest caused by CAS-related tachyarrhythmias, or even bradyarrhythmias, implantation of an ICD or pacemaker, respectively, should be considered according to the risk of recurrence and efficacy of vasodilator therapy

    Relation Between Platelet Response to Exercise and Coronary Angiographic Findings in Patients With Effort Angina

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    Background— Platelet reactivity is increased by exercise in patients with obstructive coronary artery disease (CAD) but not in patients with syndrome X. In this study, we prospectively investigated whether the platelet response to exercise might help distinguish, among patients with angina, those with obstructive CAD from those with normal coronary arteries (NCAs). Methods and Results— Venous blood samples were collected before and 5 minutes after exercise from 194 consecutive patients with stable angina. Platelet reactivity was measured by the platelet function analyzer (PFA)-100 system as the time for flowing whole blood to occlude a collagen-adenosine diphosphate ring (closure time). Coronary angiography showed CAD in 163 patients (84%) and NCA in 31 patients (16%). Baseline closure time was shorter in NCA patients (78.0±16 versus 95.5±23 seconds, P <0.0001). With exercise, closure time decreased in CAD patients (−15.5 seconds; 95% confidence limits [CL], −13.0 to −18.0 seconds; P <0.0001), but increased in NCA patients (12.5 seconds; 95% CL, 7.4 to 17.7 seconds; P =0.0004). An increase in closure time with exercise ≥10 seconds had 100% specificity and positive predictive value for NCAs. Similarly, a decrease ≥10 seconds had 100% specificity and positive predictive value for CAD. A closure time change (increase or decrease) ≥10 seconds allowed a correct classification of 55% of all patients. Conclusions— Among patients with stable angina, the response of platelet reactivity to exercise was predictive of normal or stenosed coronary arteries at angiography. Specifically, an increase in closure time with exercise ≥10 seconds was invariably associated with the presence of NCA

    The golden fig: a plasmonic effect study of organic-based solar cells

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    An optimization work on dye-sensitized solar cells (DSSCs) based on both artificial and natural dyes was carried out by a fine synthesis work embedding gold nanoparticles in a TiO(2) semiconductor and perfecting the TiO(2) particle sizes of the scattering layer. Noble metal nanostructures are known for the surface plasmon resonance peculiarity that reveals unique properties and has been implemented in several fields such as sensing, photocatalysis, optical antennas and PV devices. By embedding gold nanoparticles in the mesoporous TiO(2) layer and adding a scattering layer, we were able to boost the power conversion efficiency (PCE) to 10.8%, using an organic ruthenium complex. The same implementation was carried out using a natural dye, betalains, extracted from Sicilian prickly pear. In this case, the conversion efficiency doubled from 1 to 2% (measured at 1 SUN illumination, 100 mW/cm(2) under solar simulation irradiation). Moreover, we obtained (measured at 0.1 SUN, 10 mW/cm(2) under blue light LED irradiation) a record efficiency of 15% with the betalain-based dye, paving the way for indoor applications in organic natural devices. Finally, an attempt to scale up the system is shown, and a betalain-based- dye-sensitized solar module (DSSM), with an active area of 43.2 cm(2) and a PCE of 1.02%, was fabricated for the first time

    Myocardial infarction with nonobstructive coronary arteries: from pathophysiology to therapeutic strategies

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    : Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a heterogeneous group of clinical entities characterized by clinical evidence of acute myocardial infarction (AMI) with normal or near-normal coronary arteries on coronary angiography (stenosis &lt; 50%) and without an over the alternative diagnosis for the acute presentation. Its prevalence ranges from 6% to 11% among all patients with AMI, with a predominance of young, nonwhite females with fewer traditional risks than those with an obstructive coronary artery disease (MI-CAD). MINOCA can be due to either epicardial causes such as rupture or fissuring of unstable nonobstructive atherosclerotic plaque, coronary artery spasm, spontaneous coronary dissection and cardioembolism in-situ or microvascular causes. Besides, also type-2 AMI due to supply-demand mismatch and Takotsubo syndrome must be considered as a possible MINOCA cause. Because of the complex etiology and a limited amount of evidence, there is still some confusion around the management and treatment of these patients. Therefore, the key focus of this condition is to identify the underlying individual mechanisms to achieve patient-specific treatments. Clinical history, electrocardiogram, echocardiography, and coronary angiography represent the first-level diagnostic investigations, but coronary imaging with intravascular ultrasound and optical coherent tomography, coronary physiology testing, and cardiac magnetic resonance imaging offer additional information to understand the underlying cause of MINOCA. Although the prognosis is slightly better compared with MI-CAD patients, MINOCA is not always benign and depends on the etiopathology. This review analyzes all possible pathophysiological mechanisms that could lead to MINOCA and provides the most specific and appropriate therapeutic approach in each scenario

    Targeting prolyl-isomerase Pin1 prevents mitochondrial oxidative stress and vascular dysfunction: insights in patients with diabetes

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    The present study demonstrates that Pin1 is a common activator of key pathways involved in diabetic vascular disease in different experimental settings including primary human endothelial cells, knockout mice, and diabetic patients. Gene silencing and genetic disruption of Pin1 prevent hyperglycaemia-induced mitochondrial oxidative stress, endothelial dysfunction, and vascular inflammation. Moreover, we have translated our findings to diabetic patients. In line with our experimental observations, Pin1 up-regulation is associated with impaired flow-mediated dilation, increased oxidative stress, and plasma levels of adhesion molecules. In perspective, these findings may provide the rationale for mechanism-based therapeutic strategies in patients with diabete

    TAKO-TSUBO CARDIOMYOPATHY AND THYROID DYSFUNCTION

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    This work provides important information about the correlation between Tako-Tsubo Cardiomyopathy (TTC) and Thyroid dysfunction (TD). The article gives evidence to how doctors may have to refer to when confronted with a patients with such condiction as thyroid dysfunction and TTC, and the diverse methods that can be used to treat these conditions (TTC with TD)

    Guideline on carotid surgery for stroke prevention: updates from the Italian Society of Vascular and Endovascular Surgery. A trend towards personalized medicine

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    Background: This guideline (GL) on carotid surgery as updating of "Stroke: Italian guidelines for Prevention and Treatment" of the ISO-SPREAD Italian Stroke Organization-Group, has recently been published in the National Guideline System and shared with the Italian Society of Vascular and Endovascular Surgery (SICVE) and other Scientific Societies and Patient's Association. Methods: GRADE-SIGN version, AGREE quality of reporting checklist. Clinical questions formulated according to the PICO model. Recommendations developed based on clinical questions by a multidisciplinary experts' panel and patients' representatives. Systematic reviews performed for each PICO question. Considered judgements filled by assessing the evidence level, direction, and strength of the recommendations. Results: The panel provided indications and recommendations for appropriate, comprehensive, and individualized management of patients with carotid stenosis. Diagnostic and therapeutic processes of the best medical therapy, carotid endarterectomy (CEA), carotid stenting (CAS) according to the evidences and the judged opinions were included. Symptomatic carotid stenosis in elective and emergency, asymptomatic carotid stenosis, association with ischemic heart disease, preoperative diagnostics, types of anesthesia, monitoring in case of CEA, CEA techniques, comparison between CEA and CAS, post-surgical carotid restenosis, and medical therapy are the main topics, even with analysis of uncertainty areas for risk-benefit assessments in the individual patient (personalized medicine [PM]). Conclusions: This GL updates on the main recommendations for the most appropriate diagnostic and medical-surgical management of patients with atherosclerotic carotid artery stenosis to prevent ischemic stroke. This GL also provides useful elements for the application of PM in good clinical practice
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