An Analytical Development of the Hyperbolic Behaviour of Micro Thermoelectric Coolers

The transient behaviour of a micro thermoelectric cooler is described in the present paper through the theory of the thermal wave, involving the relaxation time. The internal heat generation due to the sudden application of the electric current is taken into account by means of the Heaviside function. The governing equations of both the semiconductors are solved by a modified Separation of Variables Method that allows us to have a better description of the device which can be obtained at early times. As regards the performances, the cooling load shows discontinuities due to the contributions of the travelling wave fronts of both the semiconductors. The results show that the coefficient of performance (COP) of the device obtained with the hyperbolic model is lower than that provided by the parabolic model at early times

Effect of Heat Source and Imperfect Contact on Simultaneous Estimation of Thermal Properties of High-Conductivity Materials

In the current paper a novel methodology accounting for both the heater heat capacity and the imperfect thermal contact between a thin heater and a specimen is proposed. In particular, the volumetric heat capacity of the heater is considered by modelling it as a lumped capacitance body, while the imperfect thermal contact is considered by means of a contact resistance. Thus, the experimental apparatus consisting of three layers (specimen-heater-specimen) is reduced to a single finite layer (sample) subject to a "nonclassical" boundary condition at the heated surface, known as sixth kind. Once the temperature solution is derived analytically using the Laplace transform method, the scaled sensitivity coefficients are computed analytically at the interface between the heater and the sample (heater side and sample side) and at the sample backside. By applying the proposed methodology to a lab-controlled experiment available in the specialized literature, a reduction of the thermal properties values of about 1.4% is observed for a high-conductivity material (Armco iron)

Retrospective descriptive analysis of the physiological kinetics of prostate-specific antigen in men older than 75 years.

Several studies have compared prostate-specific antigen (PSA) kinetics in men with and without cancer, but there has been no adequate analysis of the longitudinal variation in PSA. The aim of this study was to assess the fluctuations in PSA in a cohort of elderly men in an attempt to define a physiological pattern of PSA kinetics. We searched a specific cohort of patients aged > 75 years and with PSA value < 2.0 ng mL(-1). A history of all PSA values over the past 10 years was compiled for each patient to create a database of patients fitting the following criteria: (1) minimum of five PSA measurements, (2) over at least 5 years. Exclusion criteria were: (1) PSA < 0.2 ng mL(-1) at each measurement and (2) having had more than one PSA test per year. In all, 1 327 patients (mean age: 78.52 years) fit the inclusion criteria. The mean variation from the first to the last PSA test was 0.05 +/- 0.43, with a mean follow-up of 6.79 +/- 1.71 years. Over the same period, the mean fluctuation from the lowest to the highest PSA value was 0.04 +/- 0.55 (P = 0.925). The mean annual PSA velocity (PSAV) was calculated by dividing the mean variation from the first to the last PSA test by the number of years of observation for each patient and was set at 0.0104 +/- 0.1050. Concluding, in a large-scale cohort of elderly individuals considered healthy and evaluated for a considerable follow-up, the average annual PSAV as well as the average fluctuation from the lowest to the highest PSA value are insignificant

A rare case of primary gastric Burkitt's lymphoma associated with malignant pleural mesothelioma

Il linfoma di Burkitt (BL) e il mesotelioma pleurico maligno (MPM) sono tumori rari con prognosi infausta e nella maggior parte dei pazienti è indicato solo il trattamento palliativo. Il ruolo dell'infezione da HIV e da EBV nell'eziologia del BL sono stati confermati, mentre resta controversa l’associazione del BL a localizzazione gastrica con l’Helicobacter pylori. Il BL è endemico in Africa e sporadico nel resto del mondo, la localizzazione primitiva nello stomaco (PG BL) è estremamente rara, fino al 2017 erano stati descritti solo 53 casi, ed è altamente aggressiva con una frazione di crescita tra le più alte tra i tumori maligni. La sintomatologia di esordio è costituita da vomito, dolore post-prandiale, sanguinamento acuto o cronico. L'MPM è solitamente associato all'esposizione all'amianto e la dispnea dovuta a versamento pleurico è la manifestazione clinica tipica. Finora in Letteratura non sono stati descritti casi caratterizzati dall’associazione del mesotelioma pleurico maligno con il linfoma gastrico primitivo di Burkitt. Qui riportiamo il caso di un maschio caucasico di 80 anni, negativo per i comprovati fattori di rischio per LB e MPM, che si presentava alla nostra attenzione per un quadro di insufficienza respiratoria acuta da versamento pleurico massivo nell’emitorace sinistro, con sbandieramento mediastinico controlaterale. La tomografia computerizzata con mdc (CE-CT) mostrava una grossa massa causa di ispessimento circonferenziale del fondo gastrico, infiltrante la cupola diaframmatica sinistra e il pilatro omolaterale. All'esame endoscopico, il fondo gastrico appariva completamente occupato da una grossa massa ulcerata sporgente nel lume gastrico. L'esame istopatologico ed immunoistochimico dei campioni bioptici prelevati durante l'EGDS e la toracoscopia ha permesso di formulare la diagnosi di PG BL e MPM. Il paziente è stato sottoposto prima a posizionamento di drenaggio toracico per il versamento pleurico e poi a talcaggio pleurico toracoscopico nell'emitorace sinistro. Per la rapida crescita e l'elevato rischio di sanguinamento veniva programmato il trattamento chirurgico della lesione gastrica, ma il paziente è deceduto a causa di un'aritmia cardiaca fatale, prima di sottoporsi all’intervento chirurgico addominale. Questo case report mette in evidenza la vera sfida per i medici che è quella di identificare il MPM e il PG BL nella loro fase iniziale, specialmente nei pazienti senza i fattori di rischio comprovati. I sintomi di esordio ne fanno un caso molto singolare, caratterizzato da grave dispnea fino all'insufficienza respiratoria, per versamento pleurico massivo sinistro e sbanderiamento mediastinico controlaterale, senza sanguinamento attivo dalla massa gastrica, mentre i reperti CE-TC erano invece negativi per ispessimento pleurico e positivo per ispessimento circonferenziale del fondo gastrico.Background: Primary gastric Burkitt lymphoma (PG BL) and malignant pleural mesothelioma (MPM) are rare and aggressive tumors with poor prognosis. HIV and EBV infection have a link in the aetiology of PG BL, while MPM is usually associated with asbestos exposure. Endoluminal bleeding from massive solid tumor, and dyspnea usually due to pleural effusion, are the typical clinical manifestations respectively of PG BL and MPM. In most patients just palliative treatment is indicated. Case report: A caucasian elderly male, negative for the proven risk factors, presenting respiratory failure due to massive left pleural effusion with severe mediastinal shift. Contrast enhanced - Computed Tomography (CE-CT) showed a large mass causing circumferential thickening of the gastric fundus, infiltrating the left diaphragmatic dome and the ipsilateral crus. Macroscopically, on endoscopy the gastric fundus appeared completely occupied by an ulcerated large mass protunding in the gastric lumen. Histopathological examination from biopsy specimens taken during esophagogastroduodenoscopy and thoracoscopy allowed to make diagnosis of PG BL and MPM. The patient first underwent a placement of a chest tube drainage for the pleural effusion and then a thoracoscopic talc insufflation (TTI) in the left hemithorax. A surgical treatment of the gastric lesion was planned, due to the rapid growth and the high risk of bleeding. The patient died because of fatal cardiac arrhythmia, before undergoig abdominal surgery. Conclusions: This report presents an unique case of PG BL associated with MPM and highlights the real challenge for the physicians to identify them in early stage, especially in patients without the proved risk factors. The onset symptoms make it a very singular case, characterized by severe dyspnea up to respiratory failure, due to massive left pleural effusion and contralateral mediastinal fluttering, without an active bleeding from the gastric mass, while CE-CT findings were instead negative for pleural thickening and positive for circumferential thickening of the gastric fundus. Key words: Burkitt Lymphoma, Case Report, Gastric, Pleural Mesothelioma, Pleural Effusion, Respiratory Failure

Three-dimensional virtual reconstruction with DocDo: A novel interactive tool to score renal mass complexity

The pre-operative knowledge of the complexity of a renal mass is the cornerstone to plan a partial nephrectomy(PN) [1]. Given the multiple issues characterizing it - size, protrusion out from renal parenchyma, longitudinal and coronal location, proximity to the hilum - nephrometric scoring systems have been proposed during the last decade[2, 3]; RENAL and PADUA classifications are the mostly used [4-6]

ORal anticoagulants In fraGile patients with percutAneous endoscopic gastrostoMy and atrIal fibrillation: the (ORIGAMI) study

BACKGROUND: Randomized trials support the safety and efficacy of direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs) in patients with nonvalvular atrial fibrillation, leading to increased use of these compounds. Crushed forms of DOACs have been shown to be reliable, but evidence supporting percutaneous endoscopic gastrostomy (PEG) delivery is lacking. PEG is a long-term option for enteral food and drug delivery in patients unable to maintain oral intake, bypassing the risks and disadvantages of parenteral nutrition.AIMS: The ORal anticoagulants In fraGile patients with percutAneous endoscopic gastrostoMy and atrIal fibrillation (ORIGAMI) study investigates the safety and efficacy of Edoxaban administered via PEG in patients with atrial fibrillation and a clinical indication for a long-term anticoagulation.DESIGN: In this prospective, single-centre observational study, 12 PEG-treated patients with indication to anticoagulation will receive edoxaban via PEG and will be followed up to 6 months. Plasma antifactor Xa activity and edoxaban concentrations will be assessed. Thromboembolic (ischaemic stroke, systemic embolism, venous thromboembolism) and bleeding events (Bleeding Academic Research Consortium and Thrombolysis in Myocardial Infarction) will be recorded at 1 and 6 months.PRELIMINARY CASES: A retrospective analysis of five atrial fibrillation cases undergoing PEG implantation at our Institution who received edoxaban via PEG showed plasma anti-FXa levels at a steady state of 146 ± 15 ng/ml, without major adverse event at a mean follow-up of 6 months.CONCLUSION: ORIGAMI prospectively investigates PEG-administration of edoxaban in PEG-treated patients requiring long-term anticoagulation. Our preliminary retrospective data support this route of DOAC administration. CLINICALTRIALS.GOV IDENTIFIER: NCT04271293

Aspetti epidemiologici della calcolosi di calcio in Italia: distribuzione dei fenotipi intermedi nella popolazione italiana

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