Existence and uniqueness of slightly compressible Boussinesq's flow in Darcy-B\'enard problem

In the present paper, we study the existence, uniqueness and behaviour in time of the solutions to the Darcy-B\'enard problem for an extended-quasi-thermal-incompressible fluid-saturated porous medium uniformly heated from below. Unlike the classical problem, where the compressibility factor of the fluid vanishes, in this paper we allow the fluid to be slightly compressible and we address the well-posedness analysis for the full nonlinear initial boundary value problem for the perturbed system of governing equations modelling the convection in porous media phenomenon

A Darcy-Brinkman Model for Penetrative Convection in LTNE

The aim of this paper is to investigate the onset of penetrative convection in a Darcy-Brinkmann porous medium under the hypothesis of local therma non-equilibrium. For the problem at stake, the strong form of the principle of exchange of stabilities has been proved, i.e. convective motions can occur only through a secondary stationary motion. We perform linear and nonlinear stability analyses of the basic state motion, with particular regard to the behaviour of the stability thresholds with respect to the relevant physical parameters characterizing the model. The Chebyshev-$\tau$ method and the shooting method are employed and implemented to solve the differential eigenvalue problems arising from linear and nonlinear analyses to determine critical Rayleigh numbers. Numerical simulations prove the stabilising effect of upper bounding plane temperature, Darcy's number and the interaction coefficient characterising the local thermal non-equilibrium regime

Left ventricular diastolic filling alterations in subjects with mitral valve prolapse: a Doppler echocardiographic study

To assess left ventricular diastolic filling in mitral valve prolapse (MVP), we studied 22 patients with idiopathic MVP and 22 healthy controls matched for sex, age, body surface area and heart rate. A two-dimensional, M-mode and Doppler echocardiographic examination was performed to exclude any cardiac abnormalities. The two groups had similar diastolic and systolic left ventricular volumes, left ventricle mass and ejection fraction. Doppler measurements of mitral inflow were: E and A areas (the components of the total flow velocity-time integral in the early passive period of ventricular filling, E; and the late active period of atrial emptying, A), the peak E and A velocities (cm.s-1), acceleration and deceleration half-times (ms) of early diastolic rapid inflow, acceleration time of early diastolic flow (AT), total diastolic filling time (DFT) (ms), and the deceleration of early diastolic flow (cm.s-2). From these measurements were calculate: peak A/E ratio (A/E), E area/A area, the early filling fraction, the atrial filling fraction, AT/DFT ratio. All the Doppler measurements reported are the average of three cardiac cycles selected at end expiration. The mean peak A velocity, A/E velocity ratio, deceleration half time and atrial filling fraction were each significantly higher for subjects presenting a MVP (60 +/- 12 cm.s-1 vs 49 +/- 14, P < 0.008; 98 +/- 13% vs 64 +/- 12%, P < 0.0001; 120 +/- 36 ms vs 92 +/- 11, P < 0.002; 0.45 +/- 0.14 vs 0.36 +/- 0.08, P < 0.02

The onset of penetrative convection in an inclined porous layer

In the present article, a model for penetrative convection in a fluid-saturated inclined porous medium is analyzed. Penetrative convection occurs when an unstably stratified fluid moves into a stably stratified region. In this study, it will be shown that the inclination of the layer plays a relevant role for the penetrative thermal convection of a fluid-saturated porous medium. The results reported in the literature for the limiting case of horizontal layer are recovered and the numerical results for the linear instability, obtained via the Chebyshev-τ method, show that the most destabilizing perturbations are the longitudinal and, as expected, the transverse ones destabilize only up to a certain critical inclination angle of the layer. Moreover, in the numerical analysis of the three-dimensional perturbations, we show that the longitudinal perturbations are the most destabilizing not only with respect to the transverse but also with respect to any general perturbation. We also give nonlinear stability results for the longitudinal perturbations via the weighted energy method.</p

Endoscopic Resection of a Large Colonic Lipoma: Case Report and Review of Literature

Colonic lipomas are uncommon, benign, submucosal adipose tumors that are usually asymptomatic. Large lipomas can cause symptoms such as constipation, abdominal pain, rectal bleeding and intussusception. We report the case of a 60-year-old man with a history of lower abdominal pain and pseudoobstructive symptoms. Colonoscopy revealed a large polypoid sessile lesion in the sigma. We used a standardized technique of polypectomy, preceded by submucosal injection of dilute 5 ml polygelin with epinephrine 1:10,000 solution, to fully resect large colonic lipomas. The lipoma size was 3.5 cm. No bleeding or perforation developed. Histology showed the polyp to be a submucosul lipoma. On follow-up, there was no residual lesion. Colonic lipomas larger than 2 cm can be safely and efficaciously removed using electrosurgical snare polypectomy technique. The technique of submucosal injection before resection and using an electrocautery snare appears to be safe and reduces the risk of perforation reported in the literature

Could Hop-derived Bitter Compounds Improve Glucose Homeostasis by Stimulating the Secretion of GLP-1?

Hops (Humulus lupulus L.) is by far the greatest contributors to the bitter property of beer. Over the past years, a large body of evidence demonstrated the presence of taste receptors in different locations of the oral cavity. In addition to the taste buds of the tongue, cells expressing these receptors have been identified in olfactory bulbs, respiratory and gastrointestinal tract. In the gut, the attention was mainly directed to sweet Taste Receptor (T1R) and bitter Taste Receptor (T2R) receptors. In particular, T2R has shown to modulate secretion of different gut hormones, mainly Glucagon-like Peptide 1 (GLP-1), which are involved in the regulation of glucose homeostasis and the control of gut motility, thereby increasing the sense of satiety. Scientific interest in the activity of bitter taste receptors emerges because of their wide distribution in the human species and the large range of natural substances that interact with them. Beer, whose alcohol content is lower than in other common alcoholic beverages, contains a considerable amount of bitter compounds and current scientific evidence shows a direct effect of beer compounds on glucose homeostasis. The purpose of this paper is to review the available literature data in order to substantiate the novel hypothesis of a possible direct effect of hop-derived bitter compounds on secretion of GLP-1, through the activation of T2R, with consequent improvement of glucose homeostasis

The TNM classification of breast cancer: need for change

n/

Is Nasobiliary Tube Really Safe? A Case Report

A case of esophageal ulcer caused by nasobiliary tube is described. This tool is not routinely considered to be a cause of major complications in the literature and to our knowledge, this is the first report of this kind of complication in nasobiliary tube placement. A 72-year-old patient presented with Charcot's triad and was demonstrated to have cholangitis with multiple biliary stones in the common bile duct. Biliary drainage was achieved through endoscopic retrograde cholangiography, endoscopic sphincterotomy, biliary tree drainage and nasobiliary tube with double pigtail. The patient presented odynophagia, dysphagia and retrosternal pain 12 h after the procedure and upper endoscopy revealed a long esophageal ulcer, which was treated conservatively. This report provides corroboration of evidence that nasobiliary tube placement has potential complications related to pressure sores. In our opinion this is a possibility to consider in informed consent forms

Surgical Treatment of Coledochal Cyst Associated with an Aberrant Posterior Hepatic Duct: Report of a Case and Brief Literature Review

Choledochal cysts (CCs) are rare congenital cystic or fusiform dilatations of the biliary tree that can involve the extrahepatic and/or intrahepatic biliary tree. We report a case of huge type I CC associated with an aberrant posterior hepatic duct. A 52-year-old man presented with a 3-week history of upper right abdominal pain and jaundice and serologic sign of obstructive jaundice. Ultrasonography (US), magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography were performed with the diagnosis of CC type I according to the classification of Alonso-Lej and Todani-Watanabe. The indication for surgical resection was posed. The cyst was completely resected and the biliary tract was reconstructed with a double hepatico-jejunostomy using the same Roux limb, since during the surgical dissection a before unrecognized anatomical variation of the right biliary tree (aberrant posterior hepatic duct at VI–VII segment) was identified. The diagnosis of CC is often difficult and US and magnetic resonance cholangiopancreatography are necessary to definite biliary dilatation. Endoscopic retrograde cholangiopancreatography should be the most definitive and reliable procedure for the diagnosis and treatment of bilio-pancreatic disorders. Gold standard treatment is surgery (bilio-jejunostomy) and frozen-section histology should be performed to rule out the presence of cancer. In conclusion, surgery is the gold standard for the treatment of CC type I and does not depend on the age of patients, based on a substantial lifetime risk of developing cholangiocarcinoma. Preoperative study is mandatory to assess the biliary tree morphology and to research any anatomical variation