A code to perform harmonic analysis of a time series

Nella fisica degli acceleratori, un parametro importante è il tune di betatrone, definito come la frequenza di oscillazione trasversale del fascio. La ricerca del tune è matematicamente equivalente al calcolo della frequenza principale (ed eventualmente delle frequenze successive) di una sequenza di numeri complessi. Lo scopo di questo lavoro di tesi è produrre un programma C++ che implementi alcuni algoritmi noti di ricerca della frequenza principale e delle frequenze successive, e confermare che gli errori di questi metodi concordino con l’andamento teorico. Questa procedura è stata svolta sia per sequenze di ampiezza costante, che di ampiezza variabile nel tempo. È stato inoltre verificato che, nel secondo caso, metodi alternativi per il calcolo dell'inviluppo non sono migliori di quello usato al momento. Infine, è stato studiato e implementato un nuovo algoritmo per il calcolo simultaneo delle due frequenze dominanti. È stato verificato che, se le frequenze sono abbastanza vicine, il nuovo algoritmo è più preciso degli altri considerati

Interleukin 6 reduces vascular smooth muscle cell apoptosis via Prep1 and is associated with aging

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Treatment of very old patients with non valvular atrial fibrillation. The valuable opportunity offered by New Oral Anticoagulants, to be cautiously used

Atrial Fibrillation (AF) is the most frequent cardiac arrhythmia and its incidence increases with age reaching a 10% prevalence in the oldest old. Patients with AF have a five-fold increase in the risk of stroke. Current guidelines on AF management recommend the prescription of oral anticoagulant therapy in patients at medium and high risk of thromboembolic events. Advanced age is a risk factor for stroke in AF, but despite clear evidences a high rate of OAT under prescription is reported and particularly in the oldest old. Among the main causes of this phenomenon an enhanced risk of bleeding is often reported: this due to several factors: risk of falls, the presence of comorbidity and polifarmacy and a reduction in compliance and adherence that are common in the elderly. In recent years the international scenario in the management of OAT has significantly changed since the introduction of the new oral anticoagulants (NOA): Dabigatran, a direct thrombin inhibitor, and two oral factor Xa inhibitors Rivaroxaban and Apixaban, which have all been tested in randomized clinical trial (RELY, ROCKET-AF e ARISTOTLE) which have demonstrated non inferiority compared to warfarin in the prevention of thromboembolic events with an optimal safety profile. NOA could be an important therapeutic opportunity for stroke prevention in elderly patients with AF even if the substantial differences in mean age, anthropometric measures and comorbidity of the patients enrolled in these trials compared with those of the real world setting, oblige some caution and discussion

Mechanical ventilation weaning issues can be counted on the fingers of just one hand: part 2

Assessing heart and diaphragm function constitutes only one of the steps to consider along the weaning path. In this second part of the review, we will deal with the more systematic evaluation of the pulmonary parenchyma-often implicated in the genesis of respiratory failure. We will also consider the other possible causes of weaning failure that lie beyond the cardio-pulmonary-diaphragmatic system. Finally, we will take a moment to consider the remaining unsolved problems arising from mechanical ventilation and describe the so-called protective approach to parenchyma and diaphragm ventilation

Cardiac surgery in the elderly: What goals of care?

At present, the majority of cardiac surgery interventions have been performed in the elderly with successful short-term mortality and morbidity, however significant difficulties must to be underlined about our capacity to predict long-term outcomes such as disability, worsening quality of life and loss of functional capacity.The reason probably resides on inability to capture preoperative frailty phenotype with current cardiac surgery risk scores and consequently we are unable to outline the postoperative trajectory of an important patients' centered outcome such as disability free survival. In this perspective, more than one geriatric statements have stressed the systematic underuse of patient reported outcomes in cardiovascular trials even after taking account of their relevance to older feel and wishes. Thus, in the next future is mandatory for geriatric cardiology community closes this gap of evidences through planning of trials in which patients' centered outcomes are considered as primary goals of therapies as well as cardiovascular ones.</p

MRI lung lobe segmentation in pediatric cystic fibrosis patients using a recurrent neural network trained with publicly accessible CT datasets

PURPOSE To introduce a widely applicable workflow for pulmonary lobe segmentation of MR images using a recurrent neural network (RNN) trained with chest CT datasets. The feasibility is demonstrated for 2D coronal ultrafast balanced SSFP (ufSSFP) MRI. METHODS Lung lobes of 250 publicly accessible CT datasets of adults were segmented with an open-source CT-specific algorithm. To match 2D ufSSFP MRI data of pediatric patients, both CT data and segmentations were translated into pseudo-MR images that were masked to suppress anatomy outside the lung. Network-1 was trained with pseudo-MR images and lobe segmentations and then applied to 1000 masked ufSSFP images to predict lobe segmentations. These outputs were directly used as targets to train Network-2 and Network-3 with non-masked ufSSFP data as inputs, as well as an additional whole-lung mask as input for Network-2. Network predictions were compared to reference manual lobe segmentations of ufSSFP data in 20 pediatric cystic fibrosis patients. Manual lobe segmentations were performed by splitting available whole-lung segmentations into lobes. RESULTS Network-1 was able to segment the lobes of ufSSFP images, and Network-2 and Network-3 further increased segmentation accuracy and robustness. The average all-lobe Dice similarity coefficients were 95.0 ± 2.8 (mean ± pooled SD [%]) and 96.4 ± 2.5, 93.0 ± 2.0; and the average median Hausdorff distances were 6.1 ± 0.9 (mean ± SD [mm]), 5.3 ± 1.1, 7.1 ± 1.3 for Network-1, Network-2, and Network-3, respectively. CONCLUSION Recurrent neural network lung lobe segmentation of 2D ufSSFP imaging is feasible, in good agreement with manual segmentations. The proposed workflow might provide access to automated lobe segmentations for various lung MRI examinations and quantitative analyses

MRI lung lobe segmentation in pediatric cystic fibrosis patients using a recurrent neural network trained with publicly accessible CT datasets.

PURPOSE To introduce a widely applicable workflow for pulmonary lobe segmentation of MR images using a recurrent neural network (RNN) trained with chest CT datasets. The feasibility is demonstrated for 2D coronal ultrafast balanced SSFP (ufSSFP) MRI. METHODS Lung lobes of 250 publicly accessible CT datasets of adults were segmented with an open-source CT-specific algorithm. To match 2D ufSSFP MRI data of pediatric patients, both CT data and segmentations were translated into pseudo-MR images that were masked to suppress anatomy outside the lung. Network-1 was trained with pseudo-MR images and lobe segmentations and then applied to 1000 masked ufSSFP images to predict lobe segmentations. These outputs were directly used as targets to train Network-2 and Network-3 with non-masked ufSSFP data as inputs, as well as an additional whole-lung mask as input for Network-2. Network predictions were compared to reference manual lobe segmentations of ufSSFP data in 20 pediatric cystic fibrosis patients. Manual lobe segmentations were performed by splitting available whole-lung segmentations into lobes. RESULTS Network-1 was able to segment the lobes of ufSSFP images, and Network-2 and Network-3 further increased segmentation accuracy and robustness. The average all-lobe Dice similarity coefficients were 95.0 ± 2.8 (mean ± pooled SD [%]) and 96.4 ± 2.5, 93.0 ± 2.0; and the average median Hausdorff distances were 6.1 ± 0.9 (mean ± SD [mm]), 5.3 ± 1.1, 7.1 ± 1.3 for Network-1, Network-2, and Network-3, respectively. CONCLUSION Recurrent neural network lung lobe segmentation of 2D ufSSFP imaging is feasible, in good agreement with manual segmentations. The proposed workflow might provide access to automated lobe segmentations for various lung MRI examinations and quantitative analyses

[The complexity of risk stratification in older patient candidate to non-cardiac surgery]

During the last decades the older patients who are candidates for surgery have grown esponentially due to the increase in life expectancy and the surgery technique improvement. Despite this, the mortality remains high and our ability to predict the surgery outcomes continues to be low in the elderly. The main reason is related to different difficulties; we are unable to differentiate properly the chronological from the biological age, and the current surgery and cardiology risk scores are poorly geriatric-oriented. We must underline how the measure of comorbidity during the preoperative evaluation is often limited to a simple count of comorbid conditions, without a more detailed assessment of their severity. On the other hand different comorbidity scores have been validated in geriatric populations showing a good correlation with prognosis, such as the Index of Coexisting Disease-ICED or the Geriatric Index of Comorbidity-GIC. Our predictive deficiency about the outcomes is linked to poor attention for identifying the frail patients that are already at high risk of disability. Recently, the evaluation of frailty is a key target for geriatric medicine, and geriatricians have developed various methods for measuring this parameter and suggesting the physical performance indexes as a reliable surrogate of frailty. Surrogate frailty measures, such as the "gait speed" or the "Short Physical Performance Battery-SPPB" seem to be the valid tools for evaluating older surgery patients due to their simplicity and short administration time. We think that the future challenge will be their widespread use in this specific clinical setting

Phase and amplitude electroencephalography correlations change with disease progression in people with idiopathic rapid eye-movement sleep behavior disorder

Study Objectives Increased phase synchronization in electroencephalography (EEG) bands might reflect the activation of compensatory mechanisms of cognitive decline in people with neurodegenerative diseases. Here, we investigated whether altered large-scale couplings of brain oscillations could be linked to the balancing of cognitive decline in a longitudinal cohort of people with idiopathic rapid eye-movement sleep behavior disorder (iRBD). Methods We analyzed 18 patients (17 males, 69.7 +/- 7.5 years) with iRBD undergoing high-density EEG (HD-EEG), presynaptic dopaminergic imaging, and clinical and neuropsychological (NPS) assessments at two time points (time interval 24.2 +/- 5.9 months). We thus quantified the HD-EEG power distribution, orthogonalized amplitude correlation, and weighted phase-lag index at both time points and correlated them with clinical, NPS, and imaging data. Results Four patients phenoconverted at follow-up (three cases of parkinsonism and one of dementia). At the group level, NPS scores decreased over time, without reaching statistical significance. However, alpha phase synchronization increased and delta amplitude correlations decreased significantly at follow-up compared to baseline. Both large-scale network connectivity metrics were significantly correlated with NPS scores but not with sleep quality indices or presynaptic dopaminergic imaging data. Conclusions These results suggest that increased alpha phase synchronization and reduced delta amplitude correlation may be considered electrophysiological signs of an active compensatory mechanism of cognitive impairment in people with iRBD. Large-scale functional modifications may be helpful biomarkers in the characterization of prodromal stages of alpha-synucleinopathies.Peer reviewe