Numerical Analysis for Reduced-scale Road Tunnel Model Equipped with Axial Jet Fan Ventilation System☆

Abstract In this paper a preliminary tridimensional CFD analysis is carried out for a future realization of a reduced-scale road tunnel experimental apparatus of 1/50 equipped with different impulsive fans, traditional and alternative. The alternative jet fan is provided of inlet/outlet sections inclined at a fixed pitch angle (α=6°) toward the tunnel floor. Typically, in the experimental scale tunnel model the air flow induced by ventilation system is provided by an external fan and fully developed flow field is considered. In this paper, the authors have simulated a realistic full and reduced-scale tunnel in order to evaluate the influence of ceiling and floor roughness height on the velocity field to identify an appropriate material for a future experimental apparatus. The jet fans are simulated as a simple momentum source. The fan is considered to be infinitely thin and the discontinuous pressure rise (pressure drop) across it is defined as a function of the air velocity through the fan. In order to create a reduced-scale model from a full scale, Froude method is applied to preserve geometrical, kinematical and dynamical similitude. The results, provided in terms of axial velocity profiles in different tunnel sections, show the overlapping between velocity profiles of full scale numerical model with those of the reduced-scale model, for the both ventilation systems

Stable isotope analysis of dietary arginine accrual and disposal efficiency in male rats fed diets with different protein content.

The administration of diets with different protein/energy ratios induce variable but distinctive responses in rats; an excessive protein content tends to decrease fat accumulation, but reversion of this ratio tends to increase adipose tissue mass. The fate of N derived from amino acid metabolism is not only dependent on energy and dietary protein; the increased excretion of urea elicited by high-protein diets contrasts with the lower urea excretion (despite excess dietary protein and energy) in rats fed a cafeteria diet. After one month of exposure to high-protein (HPD) or cafeteria (CD) diets, we administered a gavage of 15N-arginine to undisturbed adult male rats, in order to trace the utilization of this not-recyclable-N amino acid under diets with different protein/energy relationships. Rats fed high-protein diet excreted higher amounts of N in urine and showed much lower gastrointestinal content of label. The CD rats decreased the excretion of urine N. Both groups' N balance showed a significant proportion of N not-accounted-for (but excreted nevertheless), the proportion being especially large in the HPD group. In conclusion, the process of disposal of amino acid N through the so far unknown pathway for 'non-accounted-for N' is, thus essentially dependent on excess amino acid availability; independently of urea cycle operation and diet energy content

Optimism and Its Impact on Mental and Physical Well-Being

Many studies have been carried out about the effectiveness of optimism as a psychological phenomenon, leading to various theoretical formulations of the same concept, conceptualized as “disposition”, “attributional style”, “cognitive bias”, or “shared illusion”. This overview is an attempt to explore the “optimism” concept and its relations with mental health, physical health, coping, quality of life and adaptation of purpose, health lifestyle and risk perception

Historia descriptiva, artística y pintoresca del Real Monasterio de S. Lorenzo comunmente llamado del Escorial : dedicada a S.M. la Reina Doña Isabel II y a su augusto esposo S.M. el Rey D. Francisco de Asis

Las h. de láminas y las ilustraciones son de vistas, planos y secciones del monasterio, escudos, retratos de personajes históricos y objetos artísticos. Las h. plegadas de láminas son una de un estandarte y la otra fachada del monasteri

Crohn's Disease Imaging: A Review

Crohn's disease is a chronic granulomatous inflammatory disease of the gastrointestinal tract, which can involve almost any segment from the mouth to the anus. Typically, Crohn's lesions attain segmental and asynchronous distribution with varying levels of seriousness, although the sites most frequently involved are the terminal ileum and the proximal colon. A single gold standard for the diagnosis of CD is not available and the diagnosis of CD is confirmed by clinical evaluation and a combination of endoscopic, histological, radiological, and/or biochemical investigations. In recent years, many studies have been performed to investigate the diagnostic potential of less invasive and more patient-friendly imaging modalities in the evaluation of Crohn's disease including conventional enteroclysis, ultrasonography, color-power Doppler, contrast-enhanced ultrasonography, multidetector CT enteroclysis, MRI enteroclysis, and 99mTc-HMPAO-labeled leukocyte scintigraphy. The potential diagnostic role of each imaging modality has to be considered in different clinical degrees of the disease, because there is no single imaging technique that allows a correct diagnosis and may be performed with similar results in every institution. The aim of this paper is to point out the advantages and limitations of the various imaging techniques in patients with suspected or proven Crohn's disease

Stem Cell Fate and Immunomodulation Promote Bone Regeneration via Composite Bio-Oss®/AviteneTM Biomaterial

Bone defects in maxillofacial regions lead to noticeable deformity and dysfunctions. Therefore, the use of biomaterials/scaffolds for maxillofacial bone regrowth has been attracting great interest from many surgical specialties and experts. Many approaches have been devised in order to create an optimal bone scaffold capable of achieving desirable degrees of bone integration and osteogenesis. Osteogenesis represents a complex physiological process involving multiple cooperating systems. A tight relationship between the immune and skeletal systems has lately been established using the concept of “osteoimmunology,” since various molecules, particularly those regulating immunological and inflammatory processes, are shared. Inflammatory mediators are now being implicated in bone remodeling, according to new scientific data. In this study, a profiler PCR array was employed to evaluate the expression of cytokines and chemokines in human adipose derived-mesenchymal stem cells (hASCs) cultured on porous hydroxylapatite (HA)/Collagen derived Bio-Oss® /Avitene scaffolds, up to day 21. In hASCs grown on the Bio-Oss® /Avitene biomaterial, 12 differentially expressed genes (DEGs) were found to be up-regulated, together with 12 DEG downregulated. Chemokine CCL2, which affects bone metabolism, tested down-regulated. Interestingly, the Bio-Oss® /Avitene induced the down-regulation of pro-inflammatory interleukin IL-6. In conclusion, our investigation carried out on the Bio-Oss® /Avitene scaffold indicates that it could be successfully employed in maxillofacial surgery. Indeed, this composite material has the advantage of being customized on the basis of the individual patients favoring a novel personalized medicine approach

Glycerol is synthesized and secreted by adipocytes to dispose of excess glucose, via glycerogenesis and increased acyl-glycerol turnover

White adipose tissue (WAT) produces large amounts of lactate and glycerol from glucose. We used mature epididymal adipocytes to analyse the relative importance of glycolytic versus lipogenic glycerol in adipocytes devoid of external stimuli. Cells were incubated (24/48 h) with 7/14 mM glucose; half of the wells contained 14C-glucose. We analysed glucose label fate, medium metabolites, and the expression of key genes coding for proteins controlling glycerol metabolism. The effects of initial glucose levels were small, but time of incubation increased cell activity and modified its metabolic focus. The massive efflux of lactate was uniform with time and unrelated to glucose concentration; however, glycerol-3P synthesis was higher in the second day of incubation, being largely incorporated into the glyceridesglycerol fraction. Glycerophosphatase expression was not affected by incubation. The stimulation of glycerogenic enzymes' expression was mirrored in lipases. The result was a shift from medium glycolytic to lipolytic glycerol released as a consequence of increased triacylglycerol turnover, in which most fatty acids were recycled. Production of glycerol seems to be an important primary function of adipocytes, maintained both by glycerogenesis and acyl-glycerol turnover. Production of 3C fragments may also contribute to convert excess glucose into smaller, more readily usable, 3C metabolites