159 research outputs found

    Modeling Photodetection at the Graphene/Ag2S Interface

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    Mixed-dimensional systems host interesting phenomena that involve electron and ion transport along or across the interface, with promising applications in optoelectronic and electrochemical devices. Herein, a heterosystem consisting of a graphene monolayer with a colloidal Ag2S nanocrystal film atop, in which both ions and electrons are involved in photoelectrical effects, is studied. An investigation of the transport at the interface in different configurations by using a phototransistor configuration with graphene as a charge-transport layer and semiconductor nanocrystals as a light-sensitive layer is performed. The key feature of charge transfer is investigated as a function of gate voltage, frequency, and incident light power. A simple analytical model of the photoresponse is developed, to gain information on the device operation, revealing that the nanocrystals transfer electrons to graphene in the dark, but the opposite process occurs upon illumination. A frequency-dependence analysis suggests a fractal interface between the two materials. This interface can be modified using solid-state electrochemical reactions, leading to the formation of metallic Ag particles, which affect the graphene properties by additional doping, while keeping the photoresponse. Overall, these results provide analytical tools and guidelines for the evaluation of coupled electron/ion transport in hybrid systems

    PERCORSI RETURN E TRAVERSAL IN UN SISTEMA DI PICKING

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    L'analisi dei percorsi return e traversal in un seistema di picking di una societĂ  di distribuzione utensili. Si evidenziano le aree di applicazione delle due differenti politiche nel caso di prelievo da scaffali a ripiani o da palle

    La procedura di ritiro e di distribuzione alimenti del Banco Alimentare

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    L'articolo analizza una nuova fonte di approvvigionamento per la raccolta e la distribuzione di derrate alimentari eccedenti, appartenenti al genere fresco, a favore di 15 enti no profit. Si definisce una nuova procedura per il ritiro e la logistica di distribuzione in Piemont

    Quantitative analysis of late gadolinium enhancement in hypertrophic cardiomyopathy

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    Background: Cardiovascular Magnetic resonance (CMR) with the late gadolinium enhancement (LGE) technique allows the detection of myocardial fibrosis in Hypertrophic cardiomyopathy (HCM). The aim of this study was to compare different methods of automatic quantification of LGE in HCM patients. Methods: Forty HCM patients (mean age 48 y, 30 males) and 20 normal subjects (mean age 38 y, 16 males) underwent CMR, and we compared 3 methods of quantification of LGE: 1) in the SD2 method a region of interest (ROI) was placed within the normal myocardium and enhanced myocardium was considered as having signal intensity>2 SD above the mean of ROI; 2) in the SD6 method enhanced myocardium was defined with a cut-off of 6 SD above mean of ROI; 3) in the RC method a ROI was placed in the background of image, a Rayleigh curve was created using the SD of that ROI and used as ideal curve of distribution of signal intensity of a perfectly nulled myocardium. The maximal signal intensity found in the Rayleigh curve was used as cut-off for enhanced myocardium. Parametric images depicting non enhanced and enhanced myocardium was created using each method. Three investigators assigned a score to each method by the comparison of the original LGE image to the respective parametric map generated. Results: Patients with HCM had lower concordance between the measured curve of distribution of signal intensity and the Rayleigh curve than controls (63.7 ± 12.3 % vs 92.2 ± 2.3%, p < 0.0001)

    Expression of Beta-Catenin, Cadherins and P-Runx2 in Fibro-Osseous Lesions of the Jaw: Tissue Microarray Study

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    Fibrous dysplasia (FD) and hyperparathyroidism-jaw tumor syndrome (HPT-JT) are wellcharacterized benign bone fibro-osseous lesions. The intracellular mechanism leading to excessive deposition of fibrous tissue and alteration of differentiation processes leading to osteomalacia have not yet been fully clarified. Tissue Microarray (TMA)-based immunohistochemical expression of  -catenin, CK-AE1/AE3, Ki-67, cadherins and P-Runx2 were analyzed in archival samples from nine patients affected by FD and HPT-JT and in seven controls, with the aim of elucidating the contribution of these molecules ( -catenin, cadherins and P-Runx2) in the osteoblast differentiation pathway.  -catenin was strongly upregulated in FD, showing a hyper-cellulated pattern, while it was faintly expressed in bone tumors associated with HPT-JT. Furthermore, the loss of expression of OBcadherin in osteoblast lineage in FD was accompanied by N-cadherin and P-cadherin upregulation (p < 0.05), while E-cadherin showed a minor role in these pathological processes. P-Runx2 showed over-expression in six out of eight cases of FD and stained moderately positive in the rimming lining osteoblasts in HPT-JT syndrome.  -catenin plays a central role in fibrous tissue proliferation and accompanies the lack of differentiation of osteoblast precursors in mature osteoblasts in FD. The study showed that the combined evaluation of the histological characteristics and the histochemical and immunohistochemical profile of key molecules involved in osteoblast differentiation are useful in the diagnosis, classification and therapeutic management of fibrous-osseous lesions

    Increased plasma homocysteine predicts arrhythmia recurrence after minimally invasive epicardial ablation for nonvalvular atrial fibrillation

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    ObjectiveMinimally invasive epicardial ablation via right minithoracotomy is an emerging option for patients with drug-refractory nonvalvular atrial fibrillation. To guide the development of rational treatment algorithms, factors predisposing to recurrence of arrhythmia need to be quantified and eventually treated. We addressed the association of the plasma levels of homocysteine and the recurrence of atrial fibrillation after minimally invasive ablation.MethodsWe obtained peripheral blood samples from 104 patients at follow-up after arrhythmia surgery; the homocysteine concentration was expressed as micromoles per liter. Prospective follow-up was conducted through electrocardiogram Holter monitoring (average 18.5 ± 5.8 months). Stratified analysis (high vs low homocysteine) was based on the cutoff value for the last quartile of homocysteine concentration (16 μmol/L). Time-to-event and diagnostic performance analyses were performed.ResultsThe rate of freedom from atrial fibrillation was 89.4% at the end of follow-up. Elevated circulating homocysteine level, persistent type of atrial fibrillation, and increased left atrial dimension independently predicted the recurrence of atrial fibrillation during the follow-up (adjusted Cox regression). Patients with a high homocysteine level were more likely to have atrial fibrillation recurrence (stratified Kaplan–Meier, P < .001). The cutoff value for elevated homocysteine (16 μmol/L) yielded a good diagnostic performance in the prediction of atrial fibrillation recurrence (area under the receiver operating characteristic curve, 0.807).ConclusionsThe homocysteine level measured during the follow-up reliably predicts the risk of recurrence after epicardial ablation of nonvalvular atrial fibrillation via minithoracotomy. Specific treatments to reduce plasma homocysteine could be considered in the future in these patients

    Prevalence, Clinical Profile, and Significance of Left Ventricular Remodeling in the End-Stage Phase of Hypertrophic Cardiomyopathy

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    Background— End stage (ES) is a recognized part of the hypertrophic cardiomyopathy (HCM) disease spectrum. Frequency, clinical profile and course, and treatment strategies in these patients remain incompletely defined. Methods and Results— Three HCM cohorts comprised 1259 patients, including 44 (3.5%) characterized as ES with systolic dysfunction (ejection fraction <50% at rest; range 15% to 49%). ES developed at a wide age range (14 to 74 years), with 45% of patients ≤40 years old. Although 29 patients (66%) died of progressive heart failure, had sudden death events, or underwent heart transplantation, 15 (34%) survived with medical management over 3±3 years. Duration from onset of HCM symptoms to ES identification was considerable (14±10 years), but ES onset to death/transplantation was brief (2.7±2 years). ES occurred with similar frequency in patients with or without prior myectomy ( P =0.84). Appropriate defibrillator interventions were 10% per year in patients awaiting donor hearts. Most ES patients (n=23; 52%) showed substantial left ventricular (LV) remodeling with cavity dilatation. Less complete remodeling occurred in 21 patients (48%), including 5 with persistence of a nondilated and markedly hypertrophied LV. Pathology and magnetic resonance imaging showed extensive (transmural) fibrosis in 9 of 11 ES patients. At initial evaluation, patients who developed ES were younger with more severe symptoms, had a larger LV cavity, and more frequently had a family history of ES than other HCM patients. Conclusions— ES of nonobstructive HCM has an expanded and more diverse clinical expression than previously appreciated, including occurrence in young patients, heterogeneous patterns of remodeling, frequent association with atrial fibrillation, and impaired LV contractility that precedes cavity dilatation, wall thinning, and heart failure symptoms. ES is an unfavorable complication (mortality rate 11% per year) and a sudden death risk factor; it requires vigilance to permit timely recognition and the necessity for defibrillator implantation and heart transplantation

    Metastasis-Directed Radiation Therapy with Consolidative Intent for Oligometastatic Urothelial Carcinoma: A Systematic Review and Meta-Analysis

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    The management of patients with oligometastatic urothelial carcinoma (UC) represents an evolving field in uro-oncology, and the role of metastasis-directed therapies, including metastasectomy and metastasis-directed radiation therapy (MDRT), is gaining increasing attention. Herein, we summarize available evidence about the role of MDRT with consolidative intent in oligometastatic UC patients. A systematic review was performed in December 2021. Six studies involving 158 patients were identified. Most patients (n = 120, 90.2%) had a history of bladder cancer and the most frequent sites of metastases were lymph nodes (n = 61, 52.1%) followed by the lungs (n = 34, 29%). Overall, 144 metastases were treated with MDRT. Median follow-up ranged from 17.2 to 25 months. Local control rates ranged from 57% to 100%. Median Overall Survival (OS) ranged from 14.9 to 51.0 months and median progression-free survival ranged from 2.9 to 10.1 months. Rates of OS at one and two years ranged from 78.9% to 96% and from 26% to 63%, respectively. Treatment-related toxicity was recorded in few patients and in most cases a low-grade toxicity was evident. MDRT with consolidative intent represents a potential treatment option for selected patients with oligometastatic UC

    Daily On-Line Set-Up Correction in 3D-Conformal Radiotherapy: Is It Feasible?

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    Aims and background The aim of this report was to investigate the feasibility in terms of treatment time prolongation of an on-line no-action level correction protocol, based on daily electronic portal image verification. Methods and study design The occupation of a linear accelerator (LINAC) delivering 3-D conformal treatments was monitored for two weeks (from Monday to Friday, 10 working days). An electronic portal image device I-View (Elekta, UK) was used for setup verification. Single-exposure portal images were acquired daily using the initial 8 monitor units delivered for each treatment field. Translational deviations of isocenter position larger than 5 mm or 7 mm, for radical or palliative treatments, respectively, were immediately corrected. In order to estimate the extra workload involved with the on-line protocol, the time required for isocenter check and table correction was specifically monitored. Results Forty-eight patients were treated. In all, 482 fractions had electronic portal images taken. Two hundred and forty-five setup corrections were made (50.8% of all fractions). The occupation of the LINAC lasted 106 h on the whole. Twelve h and 25 min (11.7% of LINAC occupation time) were spent for portal image verification and setup correction. On the average, 4.3 fractions per hour were carried out. Conclusions When used by trained therapists, ideally, portal imaging may be carried out before each fraction, requiring approximately 10% of LINAC occupation time
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