Drag Reduction in Turbulent Wall-Bounded Flows of Realistic Polymer Solutions.

Suspensions of DNA macromolecules (0.8 wppm, 60 kbp), modeled as finitely extensible nonlinear elastic dumbbells coupled to the Newtonian fluid, show drag reduction up to 27% at friction Reynolds number 180, saturating at the previously unachieved Weissenberg number ≃10^{4}. At a large Weissenberg number, the drag reduction is entirely induced by the fully stretched polymers, as confirmed by the extensional viscosity field. The polymer extension is strongly non-Gaussian, in contrast to the assumptions of classical viscoelastic models.

Single-phase anaerobic digestion of the organic fraction of municipal solid waste without dilution: Reactor stability and process performance of small, decentralised plants.

Currently, centralised plants are the most favoured approach for the anaerobic treatment of the organic fraction of municipal solid waste (OFMSW). However, centralised solutions imply certain environmental impacts, which prevent large-scale implementation of the anaerobic digestion (AD). As a result, we are digesting <5% of organic waste both in Europe and the USA even today. Pursuing the criteria for maximising the balance between profit and impacts, an innovative layout with the ultimate goal of promoting the use of small, decentralised AD plants is proposed. In this study, source-separated OFMSW (SS-OFMSW) was treated in a mesophilic plug flow reactor by applying an atypical combination of conditions such as high SS-OFMSW solid content (214.5 g·kg-1), high organic loading rate (6.2 kg VS·m-3·d-1), and no dilution or co-substrate addition. A suitable and an efficient mixing system is essential to control the process. Accordingly, the process was stable in a single-stage reactor, in the absence of digestate recirculation, obtaining specific gas production of 0.67 m3·kg-1 VS in terms of biogas and 0.41 m3·kg-1 VS in terms of methane. High reactor volume exploitation and small plant construction were feasible, reaching a gas production rate of 4.5 m3·m-3 d-1. The estimated costs in terms of capital and operating expenditure are expected to realize gross economic sustainability of full-scale installation.

The Fluid-Dynamics of Endo Vascular Aneurysm Sealing (EVAS) System failure.

PURPOSE: The main objective of this work is to investigate hemodynamics phenomena occurring in EVAS (Endo Vascular Aneurysm Sealing), to understand if and how they could lead to type 1a endoleaks and following re-intervention. To this aim, methods based on computational fluid mechanics are implemented as a tool for checking the behavior of a specific EVAS configuration, starting from the post-operative conditions. Pressure and velocity fields are detailed and compared, for two configurations of the Nellix, one as attained after correct implantation and the other in pathological conditions, as a consequence of migration or dislocation of endobags. METHODS: The computational fluid dynamics (CFD) approach is used to simulate the behavior of blood within a segment of the aorta, before and after the abdominal bifurcation. The adopted procedure allows reconstructing the detailed vascular geometry from high-resolution computerized tomography (CT scan) and generating the mesh on which the equations of fluid mechanics are discretized and solved, in order to derive pressure and velocity field during heartbeats. RESULTS: The main results are obtained in terms of local velocity fields and wall pressures. Within the endobags, velocities are usually quite regular during the whole cardiac cycle for the post-implanted condition, whereas they are more irregular for the migrated case. The largest differences among the two cases are observed in the shape and location of the recirculation region in the rear part of the aorta and the region between the endobags, with the formation of a gap due to the migration of one or both of the two. In this gap, the pressure fields are highly different among the two conditions, showing pressure peaks and pressure gradients at least four times larger for the migrated case in comparison to the post-implanted condition. CONCLUSIONS: In this paper, the migration of one or both endobags is supposed to be related to the existing differential pressures acting in the gap formed between the two, which could go on pushing the two branches one away from the other, thus causing aneurysm re-activation and endoleaks. Regions of flow recirculation and low-pressure drops are revealed only in case of endobag migration and in presence of an aneurysm. These regions are supposed to lead to possible plaque formation and atherosclerosis.

Foliar application of specific yeast derivative enhances anthocyanins accumulation and gene expression in Sangiovese cv (Vitis vinifera L.).

The effect of elicitors on secondary metabolism in vines is receiving much interest, since it has been shown that they are able to increase the accumulation of phenolics, especially anthocyanins. This research aims to investigate the biochemical and molecular effects of the application of a commercial yeast derivative (Saccharomyces cerevisiae) on the accumulation of anthocyanins in potted Sangiovese vines. Experiments were performed on three consecutive years and the yeast derivative was applied at the beginning and at the end of veraison. Technological ripening, accumulation of anthocyanins and expression of the main genes involved in their biosynthesis were assessed. Technological ripening proceeded in a similar way in both treated and untreated berries in the three years. A significant increase in the concentration of anthocyanins was instead detected, following the induction by the yeast derivative of the expression of the genes involved in their biosynthesis. The research highlights the possibility of applying a specific inactivated yeast to increase the anthocyanin concentration even under the current climate change conditions, in Sangiovese, a cultivar extremely sensitive to high temperatures.

Exact regularized point particle (ERPP) method for particle-laden wall-bounded flows in the two-way coupling regime.

The Exact Regularized Point Particle (ERPP) method is extended to treat the interphase momentum coupling between particles and fluid in the presence of walls by accounting for the vorticity generation due to the particles close to solid boundaries. The ERPP method overcomes the limitations of other methods by allowing the simulation of an extensive parameter space (Stokes number, mass loading, particle-to-fluid density ratio and Reynolds number) and of particle spatial distributions that are uneven (few particles per computational cell). The enhanced ERPP method is explained in detail and validated by considering the global impulse balance. In conditions when particles are located close to the wall, a common scenario in wall-bounded turbulent flows, the main contribution to the total impulse arises from the particle-induced vorticity at the solid boundary. The method is applied to direct numerical simulations of particle-laden turbulent pipe flow in the two-way coupling regime to address the turbulence modulation. The effects of the mass loading, the Stokes number and the particle-to-fluid density ratio are investigated. The drag is either unaltered or increased by the particles with respect to the uncoupled case. No drag reduction is found in the parameter space considered. The momentum stress budget, which includes an extra stress contribution by the particles, provides the rationale behind the drag behaviour. The extra stress produces a momentum flux towards the wall that strongly modifies the viscous stress, the culprit of drag at solid boundaries.

Low-protein diets for chronic kidney disease patients: the Italian experience.

BACKGROUND: Nutritional treatment has always represented a major feature of CKD management. Over the decades, the use of nutritional treatment in CKD patients has been marked by several goals. The first of these include the attainment of metabolic and fluid control together with the prevention and correction of signs, symptoms and complications of advanced CKD. The aim of this first stage is the prevention of malnutrition and a delay in the commencement of dialysis. Subsequently, nutritional manipulations have also been applied in association with other therapeutic interventions in an attempt to control several cardiovascular risk factors associated with CKD and to improve the patient's overall outcome. Over time and in reference to multiple aims, the modalities of nutritional treatment have been focused not only on protein intake but also on other nutrients. DISCUSSION: This paper describes the pathophysiological basis and rationale of nutritional treatment in CKD and also provides a report on extensive experience in the field of renal diets in Italy, with special attention given to approaches in clinical practice and management. Italian nephrologists have a longstanding tradition in implementing low protein diets in the treatment of CKD patients, with the principle objective of alleviating uremic symptoms, improving nutritional status and also a possibility of slowing down the progression of CKD or delaying the start of dialysis. A renewed interest in this field is based on the aim of implementing a wider nutritional therapy other than only reducing the protein intake, paying careful attention to factors such as energy intake, the quality of proteins and phosphate and sodium intakes, making today's low-protein diet program much more ambitious than previous. The motivation was the reduction in progression of renal insufficiency through reduction of proteinuria, a better control of blood pressure values and also through correction of metabolic acidosis. One major goal of the flexible and innovative Italian approach to the low-protein diet in CKD patients is the improvement of patient adherence, a crucial factor in the successful implementation of a low-protein diet program.

Pericardial fat, insulin resistance, and left ventricular structure and function in morbid obesity.

BACKGROUND AND AIM: Morbid obesity is often accompanied by insulin resistance and increased ectopic fat surrounding the heart. We evaluated the relation of epicardial and pericardial fat with insulin resistance and left ventricular (LV) structure and function. METHODS AND RESULTS: Epicardial and pericardial fat thicknesses were determined at 2-dimensional echocardiography in 80 morbid obese subjects [age 42 ± 12 years, 31% men, body mass index (BMI) 44.4 ± 7 kg/m(2)]. LV hypertrophy (LV mass ≥51 g/m(2.7)), inappropriately high LV mass for a given cardiac workload (observed vs predicted LV mass >128%), and stress-adjusted LV mid-wall fractional shortening were determined. Pericardial and epicardial fat thicknesses had direct associations with BMI (r = 0.40 and 0.45, both p < 0.01) and waist circumference (r = 0.37 and 0.45, both p < 0.01). Pericardial (partial r = 0.35, p < 0.01), but not epicardial fat thickness (partial r = 0.05, p = n.s.), was correlated with homeostasis model assessment-insulin resistance after adjustment for BMI. Pericardial fat also had a strong negative correlation with mid-wall fractional shortening (p = 0.01) and a positive one with inappropriately high LV mass (p < 0.01), while no such relation was found for epicardial fat (both p = n.s.). Independently of age, male sex, BMI, and anti-hypertensive treatment, pericardial fat thickness had an independent positive association with inappropriately high LV mass (ß = 0.29, p = 0.02), and a negative one with stress-adjusted mid-wall fractional shortening (ß = -0.26, p = 0.04). CONCLUSIONS: Pericardial fat thickness is associated with insulin resistance, inappropriately high LV mass, and LV systolic dysfunction in obese individuals. Findings from this study confirm the existence of a connection between insulin resistance, cardiac ectopic fat deposition and cardiac dysfunction in morbid obesity.

Quantum heat fluctuations of single-particle sources.

Optimal single electron sources emit regular streams of particles, displaying no low-frequency charge current noise. Because of the wave packet nature of the emitted particles, the energy is, however, fluctuating, giving rise to heat current noise. We investigate theoretically this quantum source of heat noise for an emitter coupled to an electronic probe in the hot-electron regime. The distribution of temperature and potential fluctuations induced in the probe is shown to provide direct information on the single-particle wave function properties and display strong nonclassical features.

Environmental microbial contamination in dental setting: a local experience.

INTRODUCTION: Patients and operators are exposed during dental practice to an infective risk, which derives especially from microorganisms suspended in aerosols. Environmental microbiological monitoring in dental settings represents a good instrument to detect critical situations. METHODS: In order to investigate environmental microbial contamination level in a local reality, we analyzed water, air and surfaces samples of a community-based dental facility by using protocol and threshold values proposed in a recent multicenter study carried out by the Italian Society of Hygiene, Preventive Medicine and Public Health (S.It.I.) working group "Hygiene in Dentistry". Microbial contamination was assessed in the same room for 4 non-consecutive weeks during all the five working days, before and at the end of the daily activity. Air was sampled also during clinical activity, through both active and passive sampling systems. RESULTS: Contamination of water showed a decrease during activities, while a decrease in air contamination was registered only at the end of the day. Passive sampling values resulted more often above threshold values adopted. At the same time, surfaces contamination increases at the end of the activity. It seems that in the dental clinic analyzed microbial buildup represents the higher critical element. No differences have been registered among the different days of the week. DISCUSSION: Our study highlights the need to improve disinfection procedures and air treatment systems in the considered environment. Microbiological monitoring could represent an important element to detect the presence of risk factors and to adopt control measures.

Efficacy and safety of a very-low-protein diet when postponing dialysis in the elderly: a prospective randomized multicenter controlled study.

BACKGROUND: A supplemented very-low-protein diet (sVLPD) seems to be safe when postponing dialysis therapy. STUDY DESIGN: Prospective multicenter randomized controlled study designed to assess the noninferiority of diet versus dialysis in 1-year mortality assessed by using intention-to-treat and per-protocol analysis. SETTING & PARTICIPANTS: Italian uremic patients without diabetes older than 70 years with glomerular filtration rate of 5 to 7 mL/min (0.08 to 0.12 mL/s). INTERVENTION: Randomization to an sVLPD (diet group) or dialysis. The sVLPD is a vegan diet (35 kcal; proteins, 0.3 g/kg body weight daily) supplemented with keto-analogues, amino acids, and vitamins. Patients following an sVLPD started dialysis therapy in the case of malnutrition, intractable fluid overload, hyperkalemia, or appearance of uremic symptoms. OUTCOMES & MEASUREMENTS: Mortality, hospitalization, and metabolic markers. RESULTS: 56 patients were randomly assigned to each group, median follow-up was 26.5 months (interquartile range, 40), and patients in the diet group spent a median of 10.7 months (interquartile range, 11) following an sVLPD. Forty patients in the diet group started dialysis treatment because of either fluid overload or hyperkalemia. There were 31 deaths (55%) in the dialysis group and 28 deaths (50%) in the diet group. One-year observed survival rates at intention to treat were 83.7% (95% confidence interval [CI], 74.5 to 94.0) in the dialysis group versus 87.3% (95% CI, 78.9 to 96.5) in the diet group (log-rank test for noninferiority, P < 0.001; for superiority, P = 0.6): the difference in survival was -3.6% (95% CI, -17 to +10; P = 0.002). The hazard ratio for hospitalization was 1.50 for the dialysis group (95% CI, 1.11 to 2.01; P < 0.01). LIMITATIONS: The unblinded nature of the study, exclusion of patients with diabetes, and incomplete enrollment. CONCLUSION: An sVLPD was effective and safe when postponing dialysis treatment in elderly patients without diabetes.

[Stomatologic approach in patients with congenital coagulation deficit]. / Approccio stomatologico in pazienti affetti da deficit coagulativi congeniti.

BACKGROUND: The purpose of the present paper was to resolve postoperative bleeding after oral surgery in patients with congenital coagulative defects, avoid transfusion of clotting factors and improve the patient's quality of life. METHODS: Since 1988, 1598 oral surgery procedures have been performed on patients with congenital coagulative defects treated with a protocol including pre- and postoperative tranexamic acid rinses. RESULTS: The use of tranexamic acid mouth washing has obtained effective hemostasis in 86% of cases and only 4% of surgical procedures required clotting factor transfusions. CONCLUSIONS: The results suggest that mouth washing with tranexamic acid prevents excessive oral bleeding in patients with congenital deficit of the coagulation system. Furthermore, a total elimination of the granulation tissue, that reduces the possibility of activation of the fibrinolytic mechanism, is also important.

[A health education program for the prevention of heart diseases carried out in a population in Calabria]. / Un programma di educazione sanitaria per la prevenzione delle cardiopatie realizzato in un ambito di popolazione della Calabria.

BACKGROUND: To evaluate the behaviour and knowledge of students on cardiovascular risk factors and to programme a campaign for the prevention of cardiovascular diseases. METHODS: All students attending the last year of the secondary school of this province answered a questionnaire. An educational campaign followed the analysis of the questionnaire. RESULTS: The analysis of 3675 questionnaires shows that almost all students were between 18 and 20; 16% of males (m) and 7.4% of females (f) were overweight; 1.5% and 0.4% respectively were obese; 88.8% of m and 44% of were doing physical activity; 32.4% of m and 26.8% of f were cigarette smokers. Knowledge about cardiovascular risk factors were poor. Development of the prevention campaign. In the school districts four seminars were organized to discuss about cardiovascular prevention with science teachers of the province, using audiovisual materials. The same teachers devote 4-6 hours to the same matters during school lessons. In the next months conferences destined to the population of the province will be organized. CONCLUSIONS: This program allows to promote health education in the whole population, through the students, with a low cost.

[Diltiazem in paroxysmal supraventricular tachycardia: electrocardiographic findings at termination]. / Diltiazem nella tachicardia parossistica sopraventricolare: quadri elettrocardiografici alla interruzione.

The effects of diltiazem hydrochloride (0.3 mg/kg i.v. over 2 min.) was studied by continuous electrocardiographic monitoring in 60 patients. Conversion to sinus rhythm was achieved in 55 patients (91%). Electrocardiographic findings were: undisturbed sinus rhythm in 20 patients; A-V junctional rhythm in 4 patients; complex ventricular arrhythmias (ventricular tachycardia or complex VPCs) in 19 patients. Patients with complex ventricular arrhythmias were matched against patients with normal sinus rhythm, with respect to the following parameters: age, sex, heart disease, tachycardia duration, tachycardia cycle length, sinus cycle length, pre- and post-infusion blood pressure. No differences between the two groups of patients were found. Ventricular arrhythmias occurring at the termination of supraventricular tachycardia are difficult to explain. Nevertheless, these arrhythmias are not associated with organic heart disease. They could be the expression of triggered activity.

[Arterial hypertension with hypokalemia]. / Ipertensione arteriosa con ipopotassiemia.

After a careful review of the literature on physiopathological role of the renin-angiotensin-aldosterone system in cases of arterial hypertension with hypokalaemia, a simple diagnostic procedure is suggested to differentiate between this and secondary hypertensions which, though few, are often curable. Three clinical cases examined in the medical department of Casalpusterlengo Hospital are presented in which the study of the renin-angiotensin system proved decisive for a correct diagnosis of the hypertension.

Toxic polyneuropathy of shoe workers in Italy. A clinical, neurophysiological and follow-up study.

Cases of polyneuropathy due to exposure to industrial solvents have been studied at several shoe factories in the province of Siena. After the screening of 654 employees 98 verified cases were detected. Of these, 16 were rated as moderate to severe, 45 as mild, and 37 were minimally involved but with characteristic electrodiagnostic abnormalities. Follow-up study in 53 patients showed that neurological signs and symptoms as well as electrodiagnostic abnormalities continued for years in several patients. In addition, after a year's observation, some patients showed signs of central nervous system dysfunction such as spasticity of the lower limbs and increased deep tendon reflexes. High percentages of commercial n-hexane were found in all the samples of glues and solvents collected from home-workers and from factories where cases of polyneuropathy occurred.

[Protective effect against bacterial plaque accumulation of a mouthwash containing cetylpyridinium]. / Effetto protettivo sull'accumulo della placca batterica di lun colluttorio contenente cetilpiridinio.

A mouthwash containing 0.05% cetylpyridium led to a marked reduction in the accumulation of bacterial plaque in a double-blind cross-over trial on 40 subjects. The preparation is thus a sound mean for the prevention of caries and periodontal disease. Its tolerance and subjective satisfaction were excellent.