400 research outputs found

    Reliability of third-order moment parameterization for models of turbulent boundary layer over gentle topography

    Get PDF
    An analysis is made of the transport equation of Reynolds shear stress, written in a streamline coordinate system, starting from the fields of first- and secondorder moments of wind velocity, measured in a terrain-following system over gentle topography, in order to verify the usual parameterizations of third-order moments. The equation is split into two parts: the first contains the terms which can be calculated directly from measurements, the second involves the pressure-velocity correlation considering the terms of rapid distortion, curvature and return to isotropy and the transport of triple velocity-correlation modelled assuming a flux-gradient approximation. Moreover, the error estimates associated with both parts have been computed using a Monte Carlo technique which takes into account the experimental errors. This analysis is performed on wind tunnel data over a gently shaped two-dimensional valley and hill. The comparison between the measured and modelled parts is good near the surface, whereas, at higher levels, where the pertubations induced by the topography are significant, there are large zones generally characterized by streamlines with concave curvature in which the flux-gradient approximation used to compute the triple product correlation cannot be applied

    Sharp estimates for solutions to elliptic problems with mixed boundary conditions

    Full text link
    We show, using symmetrization techniques, that it is possible to prove a comparison principle (we are mainly focused on L1L^1 comparison) between solutions to an elliptic partial differential equation on a smooth bounded set Ω\Omega with a rather general boundary condition, and solutions to a suitable related problem defined on a ball having the same volume as Ω\Omega. This includes for instance mixed problems where Dirichlet boundary conditions are prescribed on part of the boundary, while Robin boundary conditions are prescribed on its complement

    Existence of minimizers for eigenvalues of the Dirichlet-Laplacian with a drift

    Get PDF
    This paper deals with the eigenvalue problem for the operator L=-δ-x{dot operator}∇ with Dirichlet boundary conditions. We are interested in proving the existence of a set minimizing any eigenvalue λk of L under a suitable measure constraint suggested by the structure of the operator. More precisely we prove that for any c>0 and k∈N the following minimization problemmin<>{λk(Ω):Ωquasi-openset,∫Ωe|x|2/2dx≤c} has a solution

    Symmetry breaking in a constrained cheeger type isoperimetric inequality

    Get PDF
    The study of the optimal constant Kq(Ω) in the Sobolev inequality ∥u∥Lq(Ω) ≤ 1/Kq(Ω)∥Du∥(double-struck Rn), 1 ≤ q < 1∗, for BV functions which are zero outside Ω and with zero mean value inside Ω, leads to the definition of a Cheeger type constant. We are interested in finding the best possible embedding constant in terms of the measure of Ω alone. We set up an optimal shape problem and we completely characterize, on varying the exponent q, the behaviour of optimal domains. Among other things we establish the existence of a threshold value 1 ≤ q < 1∗ above which the symmetry of optimal domains is broken. Several differences between the cases n = 2 and n ≥ 3 are emphasized

    Effect of a multifactorial fall-and-fracture risk assessment and management program on gait and balance performances and disability in hospitalized older adults: a controlled study

    Get PDF
    Summary: This controlled intervention study in hospitalized oldest old adults showed that a multifactorial fall-and-fracture risk assessment and management program, applied in a dedicated geriatric hospital unit, was effective in improving fall-related physical and functional performances and the level of independence in activities of daily living in high-risk patients. Introduction: Hospitalization affords a major opportunity for interdisciplinary cooperation to manage fall-and-fracture risk factors in older adults. This study aimed at assessing the effects on physical performances and the level of independence in activities of daily living (ADL) of a multifactorial fall-and-fracture risk assessment and management program applied in a geriatric hospital setting. Methods: A controlled intervention study was conducted among 122 geriatric inpatients (mean ± SD age, 84 ± 7years) admitted with a fall-related diagnosis. Among them, 92 were admitted to a dedicated unit and enrolled into a multifactorial intervention program, including intensive targeted exercise. Thirty patients who received standard usual care in a general geriatric unit formed the control group. Primary outcomes included gait and balance performances and the level of independence in ADL measured 12 ± 6days apart. Secondary outcomes included length of stay, incidence of in-hospital falls, hospital readmission, and mortality rates. Results: Compared to the usual care group, the intervention group had significant improvements in Timed Up and Go (adjusted mean difference [AMD] = −3.7s; 95% CI = −6.8 to −0.7; P = 0.017), Tinetti (AMD = −1.4; 95% CI = −2.1 to −0.8; P < 0.001), and Functional Independence Measure (AMD = 6.5; 95%CI = 0.7-12.3; P = 0.027) test performances, as well as in several gait parameters (P < 0.05). Furthermore, this program favorably impacted adverse outcomes including hospital readmission (hazard ratio = 0.3; 95% CI = 0.1-0.9; P = 0.02). Conclusions: A multifactorial fall-and-fracture risk-based intervention program, applied in a dedicated geriatric hospital unit, was effective and more beneficial than usual care in improving physical parameters related to the risk of fall and disability among high-risk oldest old patient

    Effect of dietary antioxidant supplementation on rabbit performance, meat quality and oxidative stability of muscles

    Full text link
    [EN] The aim of this study was to cast light on the effects of EconomasE™ (EcoE), a patented pre-mixture of nutritional additives consisting mainly of organic selenium (0.15 or 0.30 mg/kg feed; Se) combined with vitamin C (5 and 10 mg/kg feed; VC), compared to DL-α-tocopherol acetate (100 or 200 mg/kg feed; VE) dietary supplementation on rabbit performance and meat quality. In fact, the role of Se supplementation in the rabbit diet has not yet been elucidated in the literature and, more specifically, there are no studies on the possible synergistic action between organic Se compared with VE on lipids, fatty acids (FA) and the oxidative stability of two glycolytic muscles, longissimus lumborum (LL) and biceps femoris (BF). Two hundred and seventy New Zealand White rabbits were divided into five dietary groups of 54 rabbits each: 1) control (basal diet = BD; CTRL); 2) VE100 (BD + VE100 mg/kg); 3) VE200 (BD + VE200 mg/kg); 4) EcoE100 (BD + EcoE100 mg/kg); and 5) EcoE200 (BD + EcoE200 mg/kg). Neither of the antioxidant treatments affected growth performance, carcass traits or meat characteristics. Lipid and fatty acid contents were similar in LL and BF and not influenced by the dietary treatment. Meat oxidative stability was strongly improved by both antioxidants. These findings indicate that both EcoE and VE greatly improved the oxidative stability of LL and BF muscles at the dosage rates which, from an economic point of view, would normally be included in the formulation of feeds for rabbits.This study is part of a multidisciplinary research project funded by the Department of Veterinary Medical Science (University of Bologna, Italy). The authors thank Martini Group Spa (Budrio di Longiano, FC, Italy) who provided animals and feeds, and Alltech (Casalecchio di Reno, BO, Italy) who supplied the EcoE.Minardi, P.; Mordenti, A.; Badiani, A.; Pirini, M.; Trombetti, F.; Albonetti, S. (2020). Effect of dietary antioxidant supplementation on rabbit performance, meat quality and oxidative stability of muscles. World Rabbit Science. 28(3):145-159. https://doi.org/10.4995/wrs.2020.12273OJS145159283Abdel-Khalek A.M. 2013. Supplemental antioxidants in rabbit nutrition: A review. Livest. Sci., 158: 95-105. https://doi.org/10.1016/j.livsci.2013.10.019Alasnier C., Gandemer G. 1998. Fatty acid and aldehyde composition of individual phospholipid classes of rabbit skeletal muscles is related to the metabolic type of the fiber. Meat Sci., 48: 225-235. https://doi.org/10.1016/S0309-1740(97)00096-XAlbonetti S., Minardi P., Trombetti F., Savigni F., Mordenti A.L., Baranzoni G.M., Trivisano C., Greco F.P., Badiani A. 2017. In vivo and in vitro effects of selected antioxidants on rabbit meat microbiota. Meat Sci., 123: 88-96. https://doi.org/10.1016/j.meatsci.2016.09.004AMSA 1995. Research guidelines for cookery, sensory evaluation and instrumental tenderness measurements of fresh meat. Chicago, Illinois, USA: American Meat Science Association in cooperation with National Live Stock and Meat Board.AOAC 2000. Official methods of analysis. Official Methods of Analysis of AOAC, 17th ed. Gaithersburg, MD, USA.AOAC 2006. Official methods of analysis. Official Methods of Analysis of AOAC, 18th ed. Gaithersburg, MD, USA.Blasco A., Ouhayoun J. 1993. Harmonisation of criteria and terminology in rabbit meat research. Revised proposal. World Rabbit Sci., 4: 93-99. https://doi.org/10.4995/wrs.1996.278Bligh E.G., Dyer W.J. 1959. A rapid method of total lipid extraction and purification. Can. J. Biochem. Physiol., 37: 911-917. https://doi.org/10.1139/o59-099Castellini C., Dal Bosco A., Bernardini M. 2001. Improvement of lipid stability of rabbit meat by vitamin E and C administration. J. Sci. Food Agric., 81: 46-53. https://doi.org/10.1002/1097-0010(20010101)81:13.0.CO;2-4Chauhan S.S., Liu F., Leury B.J., Cottrell J.J., Celi P., Dunshea F.R. 2016. Functionality and genomics of selenium and vitamin E supplementation in ruminants. Anim. Prod. Sci., 56: 1285-1298. https://doi.org/10.1071/AN15263CIE (Commission Internationale de l'Eclairage). 1976. Official recommendations on uniform colour spaces, colour differences equations and metric colour terms. Suppl. 2 to CIE, publications 15. Paris, France. https://doi.org/10.1002/j.1520-6378.1977.tb00102.xCorino C., Lo Fiego D.P., Macchioni P., Pastorelli G., Di Giancamillo A., Domeneghini C., Rossi R. 2007. Influence of dietary conjugated linoleic acids and vitamin E on meat quality, and adipose tissue in rabbits. Meat Sci., 76: 19-28. https://doi.org/10.1016/j.meatsci.2006.10.007Cullere M., Dalle Zotte A. 2018. Rabbit meat production and consumption: State of knowledge and future perspectives. Meat Sci., 143: 137-146. https://doi.org/10.1016/j.meatsci.2018.04.029Dalle Zotte A., Cullere M., Rémignon H., Alberghini L., Paci G. 2016. Meat physical quality and muscle fiber properties of rabbit meat as affected by the sire breed, season, parity order and gender in an organic production system. World Rabbit Sci., 24: 145-154. https://doi.org/10.4995/wrs.2016.4300Dalle Zotte A., Rémignon H., Ouhayoun J. 2005. Effect of feed rationing during post-weaning growth on meat quality, muscle energy metabolism and fiber properties of Biceps femoris muscle in the rabbit. Meat Sci., 70: 301-306. https://doi.org/10.1016/j.meatsci.2005.01.016Dalle Zotte A., Szendrő Z. 2011. The role of rabbit meat as functional food. Meat Sci., 88: 319-331. https://doi.org/10.1016/j.meatsci.2011.02.017Dokoupilová A., Marounek M., Skrivanova V., Brezina P. 2007. Selenium content in tissues and meat quality in rabbits fed selenium yeast. Czech. J. Anim. Sci., 52: 165-169. https://doi.org/10.17221/2319-CJASEbeid T.A., Zeweil H.S., Basyony M.M., Dosoky W.M., Badry H. 2013. Fortification of rabbit diets with vitamin E or selenium affects growth performance, lipid peroxidation, oxidative status and immune response in growing rabbits. Livest. Sci., 155: 323-331. https://doi.org/10.1016/j.livsci.2013.05.011EFSA AHAW Panel 2020. Scientific Opinion on the health and welfare of rabbits farmed in different production systems. EFSA Journal, 18: 5944. https://doi.org/10.2903/j.efsa.2020.5944Eiben Cs., Végi B., Virág Gy., Gódor-Surmann K., Kustos K., Maró A., Odermatt M., Zsédely E., Tóth T., Schmidt J., Fébel H. 2011. Effect of level and source of vitamin E addition of a diet enriched with sunflower and linseed oils on growth and slaughter traits of rabbits. Livest. Sci., 139: 196-205. https://doi.org/10.1016/j.livsci.2011.01.010Erdèlyi M., Virág G., Mézes M. 2000. Effect of supranutritional additive selenium supply on the tissue selenium concentration and the activity of glutathione peroxidase enzyme in rabbit. World Rabbit Sci., 8: 183-191.Erickson M.C. 1992. Variation of lipid and tocopherol composition in three strains of channel catfish (Ictalurus punctatus). J. Sci. Food Agric., 59: 529-536. https://doi.org/10.1002/jsfa.2740590416European Communities: Council Regulation (EC) 2011. 1169/2011 on the Provision of Food Information to Consumers. Available at: http://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32011R1169&from=EN. Accessed April 2017.Giaretta E., Mordenti A., Palmonari A., Brogna N., Canestrari G., Belloni P., Cavallini D., Mammi L., Cabbri R., Formigoni A. 2019. NIRs calibration models for chemical composition and fatty acid families of raw and freeze-dried beef: A comparison. J. Food Compost. Anal., 83: 103257. https://doi.org/10.1016/j.jfca.2019.103257Gondret F., Lebas F., Bonneau M. 2000. Restricted feed intake during fattening reduces intramuscular lipid deposition without modifying muscle fiber characteristics in rabbits. J. Nutr., 130: 228-233. https://doi.org/10.1093/jn/130.2.228Honikel K.O. 1998. Reference methods for the assessment of physical characteristics of meat. Meat Sci., 49: 447-457. https://doi.org/10.1016/S0309-1740(98)00034-5Ichihara K., Shibahara A., Yamamoto K., Nakayama T. 1996. An improved method for rapid analysis of the fatty acids of glycerolipids. Lipids, 31: 535-539. https://doi.org/10.1007/BF02522648ISO 1998. Animal feeding stuffs, animal products and faeces or urine. Determination of gross calorific value - Bomb calorimetric method (Reference number 9831). Available at: https://www.iso.org/standard/17702.html. Accessed July 2017.Kouba M., Benatmane F., Blochet J.E., Mourot J. 2008. Effect of a linseed diet on lipid oxidation, fatty acid composition of muscle, perirenal fat, and raw and cooked rabbit meat. Meat Sci., 80: 829-834. https://doi.org/10.1016/j.meatsci.2008.03.029Lee Y.H., Layman D.K., Bell R.R. 1979. Selenium-dependent and non-selenium-dependent glutathione peroxidase activity in rabbit tissue. Nutr. Rep. Int., 20: 573-578.Lo Fiego D.P., Santoro P., Macchioni P., Mazzoni D., Piattoni F., Tassone F., De Leonibus E. 2004. The effect of dietary supplementation of vitamins C and E on the α-tocopherol content of muscles, liver and kidney, on the stability of lipids, and on certain meat quality parameters of the Longissimus dorsi of rabbits. Meat Sci., 67: 319-327. https://doi.org/10.1016/j.meatsci.2003.11.004Lopez-Bote C.J., Rey A.I., Sanz M., Gray J.I., Buckley D.J. 1997. Dietary vegetable oils and α-tocopherol reduce lipid oxidation in rabbit muscle. J. Nutr., 127: 1176-1182. https://doi.org/10.1093/jn/127.6.1176Maraschiello C., Sárraga C., García Regueiro J.A. 1999. Glutathione peroxidase activity, TBARS, and α-Tocopherol in meat from chickens fed different diets. J. Agr. Food Chem., 47: 867-872. https://doi.org/10.1021/jf980824oMarounek M., Dokoupilová A., Volek Z., Hoza I. 2009. Quality of meat and selenium content in tissues of rabbits fed diets supplemented with sodium selenite, selenized yeast and selenized algae. World Rabbit Sci., 17: 207-212. https://doi.org/10.4995/wrs.2009.645Martillotti F., Antongiovanni M., Rizzi L., Santi E., Bittante G. 1987. Metodi di analisi per la valutazione degli alimenti d'impiego zootecnico. Quaderni Metodologici, 8, CNR-IPRA, Roma.Mateos G.G., Rebollar P.G., de Blas C. 2010. Minerals, vitamins and additives. In: C. DE BLAS and J. WISEMAN (Eds.) Nutrition of the rabbit. 2nd Edition. CABI Publishing, New York: USA, 119-150. https://doi.org/10.1079/9781845936693.0222Matics Z., Cullere M., Szín M., Gerencsér Zs., Szabó A., Fébel H., Odermatt M., Radnai I., Dalle Zotte A., Szendrő Zs. 2017. Effect of a dietary supplementation with linseed oil and selenium to growing rabbits on their productive performances, carcass traits and fresh and cooked meat quality. J. Anim. Physiol. Anim. Nutr., 101: 685-693. https://doi.org/10.1111/jpn.12589Mattioli S., Cardinali R., Balzano M., Pacetti D., Castellini C., Dal Bosco A., Frega N.G. 2017. Influence of dietary supplementation with prebiotic, oregano extract, and vitamin E on fatty acid profile and oxidative status of rabbit meat. J. Food Qual., Article ID 3015120, 1-9. https://doi.org/10.1155/2017/3015120McLellan M.R., Lind L.R., Kime R.W. 1995. Hue angle determinations and statistical analysis for multiquadrant hunter L,a,b data. J. Food Qual., 18: 235-240. https://doi.org/10.1111/j.1745-4557.1995.tb00377.xMézes M., Balogh K. 2009. Mycotoxins in rabbit feed: a review. World Rabbit Sci., 17: 53-62.Midttun Ø., Ueland P.M. 2011. Determination of vitamins A, D and E in a small volume of human plasma by a high-throughput method based on liquid chromatography/tandem mass spectrometry. Rapid Commun. Mass Sp., 25: 1942-1948. https://doi.org/10.1002/rcm.5073Montero-Vicente L., Escribá-Pérez C., Baviera-Puig A., Buitrago-Vera J. 2018. Analysis of the commercial value of rabbit meat based on positioning of the different types of fresh meat. Span. J. Agric. Res., 16: e0110. https://doi.org/10.5424/sjar/2018163-13407Mordenti A.L., Sardi L., Bonaldo A., Pizzamiglio V., Brogna N., Cipollini I., Tassinari M., Zaghini G. 2010. Influence of marine algae (Schizochytrium spp.) dietary supplementation on doe performance and progeny meat quality. Livest. Sci., 128: 179-184. https://doi.org/10.1016/j.livsci.2009.12.003Müller A.S., Pallauf J., Most E. 2002. Parameters of dietary selenium and vitamin E deficiency in growing rabbits. J. Trace Elem. Med. Biol., 16: 47-55. https://doi.org/10.1016/S0946-672X(02)80008-6Nambapana N.M.N., Samarasinghe K., Vidanarachchi J.K. 2015. The effect of EconomasE® as a vitamin E replacer on performance, meat quality and organ weights of broiler birds. Trop. Agric. Res., 27: 27-38. http://doi.org/10.4038/tar.v27i1.8151Oriani G., Corino C., Pastorelli G., Pantaleo L., Ritieni A., Salvatori G. 2001. Oxidative status of plasma and muscle in rabbits supplemented with dietary vitamin E. J. Nutr. Biochem., 12: 138-143. https://doi.org/10.1016/S0955-2863(00)00132-7Papadomichelakis G., Zoidis E., Pappas A.C., Mountzouris K.C., Fegeros K. 2017. Effects of increasing dietary organic selenium levels on meat fatty acid composition and oxidative stability in growing rabbits. Meat Sci., 131: 132-138. https://doi.org/10.1016/j.meatsci.2017.05.006Peiretti P.G., Gasco L., Brugiapaglia A., Gai F. 2011. Effects of perilla (Perilla frutescens L.) seeds supplementation on performance, carcass characteristics, meat quality and fatty acid composition of rabbits. Livest Sci., 138: 118-124. https://doi.org/10.1016/j.livsci.2010.12.007Petrescu D.C., Petrescu-Mag R.M. 2018. Consumer behaviour related to rabbit meat as fucntional food. World Rabbit Sci., 26: 321-333. https://doi.org/10.4995/wrs.2018.10435Pirini M., Manuzzi M.P., Pagliarani A., Trombetti F., Borgatti A.R., Ventrella V. 2007. Changes in fatty acid composition of Mytilus galloprovincialis (Lmk) fed on microalgal and wheat germ diets. Comp. Biochem. Physiol. Part B, 147: 616-626. https://doi.org/10.1016/j.cbpb.2007.04.003Ulbricht T., Southgate D. 1991. Coronary heart disease: seven dietary factors. Lancet, 338: 985-992. https://doi.org/10.1016/0140-6736(91)91846-MUnited States Environmental Protection Agency (U.S. EPA) 1986. Test methods for evaluating solid waste, 3rd Edition, Vol. 1A. SW-846. Washington, DC.Van Soest P.J., Robertson J.B., Lewis B.A. 1991. Methods for dietary fiber, neutral detergent fiber, and non-starch polysaccharides in relation to animal nutrition. J. Dairy Sci., 74: 3583-3597. https://doi.org/10.3168/jds.S0022-0302(91)78551-2Xiao R., Power R.F., Mallonee D., Crowdus C., Brennan K. M., Ao T., Pierce J.L., Dawson K.A. 2011. A comparative transcriptomic study of vitamin E and an algae-based antioxidant as antioxidative agents: Investigation of replacing vitamin E with the algae-based antioxidant in broiler diets. Poultry Sci., 90: 136-146. https://doi.org/10.3382/ps.2010-01018Zhang Y., Zhu S., Wang X., Wang C., Li F. 2011. The effect of dietary selenium levels on growth performance, antioxidant capacity and glutathione peroxidase 1 (GSHPx1) mRNA expression in growing meat rabbits. Anim. Feed Sci. Tech., 169: 259-264. https://doi.org/10.1016/j.anifeedsci.2011.07.00

    Alterations of bone microstructure and strength in end-stage renal failure

    Get PDF
    Summary: End-stage renal disease (ESRD) patients have a high risk of fractures. We evaluated bone microstructure and finite-element analysis-estimated strength and stiffness in patients with ESRD by high-resolution peripheral computed tomography. We observed an alteration of cortical and trabecular bone microstructure and of bone strength and stiffness in ESRD patients. Introduction: Fragility fractures are common in ESRD patients on dialysis. Alterations of bone microstructure contribute to skeletal fragility, independently of areal bone mineral density. Methods: We compared microstructure and finite-element analysis estimates of strength and stiffness by high-resolution peripheral quantitative computed tomography (HR-pQCT) in 33 ESRD patients on dialysis (17 females and 16 males; mean age, 47.0 ± 12.6years) and 33 age-matched healthy controls. Results: Dialyzed women had lower radius and tibia cortical density with higher radius cortical porosity and lower tibia cortical thickness, compared to controls. Radius trabecular number was lower with higher heterogeneity of the trabecular network. Male patients displayed only a lower radius cortical density. Radius and tibia cortical thickness correlated negatively with bone-specific alkaline phosphatase (BALP). Microstructure did not correlate with parathyroid hormone (PTH) levels. Cortical porosity correlated positively with "Kidney Disease: Improving Global Outcomes” working group PTH level categories (r = 0.36, p < 0.04). BMI correlated positively with trabecular number (r = 0.4, p < 0.02) and negatively with trabecular spacing (r = −0.37, p < 0.03) and trabecular network heterogeneity (r = −0.4, p < 0.02). Biomechanics positively correlated with BMI and negatively with BALP. Conclusion: Cortical and trabecular bone microstructure and calculated bone strength are altered in ESRD patients, predominantly in women. Bone microstructure and biomechanical assessment by HR-pQCT may be of major clinical relevance in the evaluation of bone fragility in ESRD patient

    Characterization of metabolic profiles and lipopolysaccharide effects on porcine vascular wall mesenchymal stem cells

    Get PDF
    The link between metabolic remodeling and stem cell fate is still unclear. To explore this topic, the metabolic profile of porcine vascular wall mesenchymal stem cells (pVW-MSCs) was investigated. At the first and second cell passages, pVW-MSCs exploit both glycolysis and cellular respiration to synthesize adenosine triphosphate (ATP), but in the subsequent (third to eighth) passages they do not show any mitochondrial ATP turnover. Interestingly, when the first passage pVW-MSCs are exposed to 0.1 or 10 μg/ml lipopolysaccharides (LPSs) for 4 hr, even if ATP synthesis is prevented, the spare respiratory capacity is retained and the glycolytic capacity is unaffected. In contrast, the exposure of pVW-MSCs at the fifth passage to 10 μg/ml LPS stimulates mitochondrial ATP synthesis. Flow cytometry rules out any reactive oxygen species (ROS) involvement in the LPS effects, thus suggesting that the pVW-MSC metabolic pattern is modulated by culture conditions via ROS-independent mechanisms
    corecore