1,827 research outputs found

    Solvability for a nonlinear coupled system of Kirchhoff type for the beam equations with nonlocal boundary conditions

    Get PDF
    In this paper, we investigate a mathematical model for a nonlinear coupled system of Kirchhoff type of beam equations with nonlocal boundary conditions. We establish existence, regularity and uniqueness of strong solutions. Furthermore, we prove the uniform rate of exponential decay. The uniform rate of polynomial decay is considered

    Liquid-liquid equilibrium of water +1-butanol + amino acid (glycine or DL-alanine or L-leucine)

    Get PDF
    Amino acid play an important role both in animal metabolism and in industrial processes. Since they are rarely found in nature in free form, they must be obtained form hydrolisis of protein-containing materials, or by fermentation. These production methods often results in aqueouse mixtures containing various solutes included several types of amino acids. As a consequence, the cost of the separation processses and concentration of biomelecules from the media can be as high as 90 per cent of their total manufacturing cost

    Proteinase activity regulation by glycosaminoglycans

    Get PDF
    There are few reports concerning the biological role and the mechanisms of interaction between proteinases and carbohydrates other than those involved in clotting. It has been shown that the interplay of enzymes and glycosaminoglycans is able to modulate the activity of different proteases and also to affect their structures. From the large number of proteases belonging to the well-known protease families and also the variety of carbohydrates described as widely distributed, only few events have been analyzed more deeply. The term family is used to describe a group of proteases in which every member shows an evolutionary relationship to at least one other protease. This relationship may be evident throughout the entire sequence, or at least in that part of the sequence responsible for catalytic activity. The majority of proteases belong to the serine, cysteine, aspartic or metalloprotease families. By considering the existing limited proteolysis process, in addition to the initial idea that the proteinases participate only in digestive processes, it is possible to conclude that the function of the enzymes is strictly limited to the cleavage of intended substrates since the destruction of functional proteins would result in normal tissue damage. In addition, the location as well as the eventual regulation of protease activity promoted by glycosaminoglycans can play an essential role in the development of several physiopathological conditions.Universidade de Mogi das Cruzes Centro Interdisciplinar de Investigação BioquímicaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de BiofísicaUNIFESP, EPM, Depto. de BiofísicaSciEL

    Physical Exercise as an Effective Antiaging Intervention

    Get PDF
    Physical exercise has been well demonstrated as an effective antiaging intervention. Although exercise certainly cannot reverse the aging process, it does attenuate many of its deleterious systemic and cellular effects. This special issue contains a set of selected papers that represent the broad spectrum in which physical exercise can contribute to a healthy aging. As documented in this issue an active lifestyle represents a powerful tool that may be described as a polypill to prevent and/or treat many conditions and diseases. The topics discussed herein include muscle fiber and muscle functioning, protein intake and sarcopenia, cognitive analysis, study of the perception of the instructors, and association of different biomarkers with physical performance..

    Tributyltin in crustacean tissues: Analytical performance and validation of method

    Get PDF
    The hermit crab Clibanarius vittatus is a typical organism from intertidal regions being considered as a good bioindicator of tributyltin presence at these environments. Thus this study presents the analytical performance and validation method for TBT quantification in tissues of C. vittatus by gas chromatography with pulsed flame photometric detector (GC-PFPD) after extraction with an apolar solvent (toluene) and Grignard derivatization. The limits of detection of the method (LOD) were 2.0 and 2.8 ng g -1 for TBT and DBT (dibutyltin), respectively, and its limits of quantification (LOQ) were 6.6 and 8.9 ng g-1 for TBT and DBT, respectively. The method was applied to samples from Santos Estuary, São Paulo State, Brazil. TBT and DBT concentrations ranged from 26.7 to 175.0 ng g -1 and from 46.2 to 156.0 ng g -1, respectively. These concentrations are worrisome since toxic effects (such as endocrine disruption) have been reported for other organisms even under lower levels of registred at this study. © 2012 Sociedade Brasileira de Química

    Beneficial effects of the ethanol extract of Caesalpinia pyramidalis on the inflammatory response and abdominal hyperalgesia in rats with acute pancreatitis

    Get PDF
    AbstractEthnopharmacological relevanceCaesalpinia pyramidalis Tul. (Fabaceae) is a plant found in the Northeast of Brazil that is popularly used to treat inflammation. Acute pancreatitis (AP) is an inflammatory disease for which abdominal pain is a relevant symptom. As there is no specific therapy for AP, we investigated the effect of the ethanol extract from the inner bark of C. pyramidalis (EECp) on the AP induced by common bile duct obstruction (CBDO) in rats.Material and methodsAP was induced in male Wistar rats (200–250g, n=6–8) through laparotomy and subsequent CBDO. Animals were euthanized after 6 (G6h) or 24h (G24h) of induction. In the G6h protocol, animals were pretreated with EECp (100–400mg/kg, p.o.) or vehicle (Tween 80; 0.2%) 1h before CBDO or sham surgery. For the G24h protocol, rats were pretreated with EECp (400mg/kg, 1h before CBDO or 1h before and 12h after CBDO) or vehicle. The following parameters were measured: inflammatory/oxidative (myeloperoxidase activity and malondialdehyde formation in the pancreas and lung, leukocyte counts in the blood and serum nitrate/nitrite), enzymatic (serum amylase and lipase levels) and nociceptive (abdominal hyperalgesia).ResultsInduction of AP by CBDO significantly increased all the parameters evaluated in both G6h and G24h protocols when compared with the respective sham group. In the G6h protocol, the EECp pretreatment (400mg/kg) significantly reduced all these parameters, besides completely inhibiting abdominal hyperalgesia. The same profile of reduction was observed from two administrations of EECp in the G24h protocol, while one single dose of EECp was able to significantly reduce pancreatic MDA, serum lipase levels, leukocyte counts in the blood and abdominal hyperalgesia without affecting the other parameters in the G24h protocol. Furthermore, rutin was found in the EECp.ConclusionsOur results demonstrated that EECp decreases inflammation, lipoperoxidation and hyperalgesia in CBDO-induced AP, making it of interest in future approaches to treat this condition

    Byrsonima Crassa Niedenzu (ik): Antimicrobial Activity And Chemical Study

    Get PDF
    The methanolic extract of leaves from Byrsonima crassa, a Brazilian medicinal plant, was analyzed by CC and HPLC. Four constituents were isolated and identified as quercetin, methyl gallate, (-)-epigallocatechin gallate and quercetin-3-O-(2″-galloyl)-α-L-arabinopyranoside. The methanolic and hydromethanolic extract, as well as fractions, were evaluated regarding their possible antimicrobial activity using in vitro methods. Results showed that both extracts and fractions exhibited significant antimicrobial activity against all tested strains.2617175Agrawal, P.K., (1989) Carbon 13NMR of Flavonoids, , Amsterdam:ElsevierAlzoreky, N.S., Nakahara, K., Antibacterial activity of extracts from some edible plants commonly consumed in Asia (2003) Int J Food Microbiol, 80, pp. 223-230Amarqiuise, A., Che, C.T., Bejar, E., Malone, M.H., Fong, H.H.S., A New Glycolipid from Byrsonima crassifolia (1994) Planta Med, 60, pp. 85-86Basile, A., Sorbo, S., Giordano, S., Ricciardi, L., Ferrara, S., Montesano, D., Cobianchi, R.C., Ferrara, L., Antibacterial and allelopathic activity of extract from Castanea sativa leaves (2000) Fitoterapia, 71, pp. S110-S116Bauer, A.W., Kirby, M.D.K., Sherries, J.C., Truck, M., Antibiotic susceptibilities testing by standard single disc diffusion method (1966) Am J Clin Pathol, 45, pp. 493-496Bejar, E., Amarquaye, A., Che, C.T., Malone, M.H., Fong, H.H.S., Constituents of Byrsonima crassifolia and their spasmogenic activity (1995) Int J Pharmacog, 33, pp. 25-32Binutu, O.A., Cordell, G.A., Gallic acid derivatives from Mezoneuron benthamianum leaves (2000) Pharm Biol, 38, pp. 284-286Djipa, C.D., Delmee, M., Quetin-Leclercq, J., Antimicrobial activity of bark extracts of Syzygium jambos (L.) Alston (Myrtaceae) (2000) J Ethnopharmacol, 71, pp. 307-313Geiss, F., Heinrich, M., Hunkler, D., Rimpler, H., Heinrich, M., Proanthocyanidins with (+)-epicatechin units from Byrsonima crassifolia bark (1995) Phytochemistry, 39, pp. 635-643Gottlieb, O.R., Henriques Mendes, P., Taveira Magalhães, M., Triterpenoids from Byrsonima verbascifolia (1975) Phytochemistry, 14, pp. 1456-1456Harborne, J.B., (1996) The Flavonoids: Advances in Research since 1986, , New York:Chapman & HallLopez, A., Hudson, J.B., Towers, G.H.N., Antiviral and antimicrobial activities of Colombian medicinal plants (2001) J Ethnopharmacol, 77, pp. 189-196Martínez-Vasquéz, M., González-Esquinca, A.R., Cazares Luna, L., Moreno Gutiérrez, M.N., García-Argáez, A.N., Antimicrobial activity of Byrsonima crassifolia (L.) H.B.K (1999) J Ethnopharmacol, 66, pp. 79-82Mendes, C.C., Cruz, F.G., David, J.M., Nascimento, I.P., David, J.P., Triterpenes esterified with fatty acid and triterpene acids isolated from Byrsonima microphylla (1999) Quím Nova, 22, pp. 185-188Nascimento, G.G.F., Locatelli, J., Freitas, P.C., Silva, G.L., Antibacterial activity of plants extracts and phytochemicals on antibiotic-resistant bacteria (2000) Braz J Microbiol, 31, pp. 247-256(2003) Performance Standards for Antimicrobial Disc Susceptibility Tests, , Approved Standard M2-A7, Pennsylvania:WaynePenna, C., Marino, S., Vivot, E., Cruanes, M.C., Munoz, J.D., Cruanes, J., Ferraro, G., Martino, V., Antimicrobial activity of Argentine plants used in the treatment of infectious diseases. Isolation of active compounds from Sebastiania brasiliensis (2001) J Ethnopharmacol, 77, pp. 37-40Pretorius, J.C., Magama, S., Zietsman, P.C., Purification and identification of antibacterial compounds from Euclea crispa subsp crispa (Ebenaceae) leaves (2003) S Afr J Bot, 69, pp. 579-586Rastrelli, L., De Tommasi, N., Berger, I., Caceres, A., Saravia, A., De Simone, F., Glycolipids from Byrsonima crassifolia (1997) Phytochemistry, 45, pp. 647-650Sannomiya, M., Rodrigues, C.M., Coelho, R.G., Santos, L.C., Hiruma-Lima, C.A., Souza Brito, A.R.M., Vilegas, W., Application of preparative high-speed counter-current chromatography for the separation of flavonoids from the leaves of Byrsonima crassa Niedenzu (IK) (2004) J Chromatogr A, 1035, pp. 47-51Sannomiya, M., Fonseca, V.B., Da Silva, M.A., Rocha, L.R.M., Dos Santos, L.C., Souza, H.C.A., Brito, A.R.M., Vilegas, W., Flavonoids and antiulcerogenic activity from Byrsonima crassa leaves extracts (2005) J Ethnopharmacol, 97, pp. 1-6Silva, S.R., Silva, A.P., Munhoz, C.B., Silva Jr., M.C., Medeiros, M.B., (2001) Guia de Plantas Do Cerrado Utilizadas Na Chapada Dos Veadeiros, , Brasília:WWF58pSrinivasan, D., Nathan, S., Suresh, T., Perumalsamy, P.L., Antimicrobial activity of certain Indian medicinal plants used in folkloric medicine (2001) J Ethnopharmacol, 74, pp. 217-220Wagner, H., Bladt, H., Zgainski, E.M., (1984) Plant Drug Analysis, , Berlin:Springer320

    Orelha de Elefante Mexicana (Opuntia stricta [Haw.] Haw.) spineless cactus as an option in crossbred dairy cattle diet

    Get PDF
    new genotype of spineless cactus is being used in the diets of dairy cattle that are raised in semi-arid regions. However, little is known about its nutritional value. This study aimed to evaluate the effects of replacing Miúda (Nopalea cochenillifera Salm Dyck) with Orelha de Elefante Mexicana (Opuntia stricta [Haw.] Haw.) spineless cactus, on nutrient intake and digestibility, milk yield and composition, feeding behaviour, microbial protein synthesis, nitrogen balance, and ruminal and blood parameters of dairy cows. Ten Girolando cows, 500 ± 51.6 kg bodyweight, were distributed in a double Latin square design 5 x 5. The treatments consisted of replacement levels of Miúda (MIU) by Orelha de Elefante Mexicana (OEM) at 0, 25, 50, 75, and 100%. The intake and digestibility of dry matter (DM) (14.38–12.95 kg d-1, 716.3–658.9 g d-1), organic matter (OM) (13.01–11.43 kg d-1, 747.8–704.8 g d-1), crude protein (CP) (2.02–1.61 kg d-1, 863.8–845.2 g d-1) and total digestible nutrients (TDN) (9.38–7.92 kg d-1) decreased linearly with the increase in replacement. Despite the decrease in intake and digestibility, the supply of nutrients was sufficient to maintain a milk yield of 12.5 kg d-1. The average daily weight gain decreased linearly with the increase in replacement, while protein microbial efficiency (g microbial CP kg-1 TDN intake; 91.24 to 127.44 g kg-1) increased linearly. Thus, OEM could replace 100% MIU in diets with 48% of spineless cactus, for crossbred lactating cows with 12.5 kg d-1 milk yield. Therefore, OEM is a viable new option for producing milk in smallholder livestock systems in semi-arid regions.Keywords: Alternative forage, milk yield, ruminal parameter, semi-arid, smallholder livestock syste

    Phonon Universal Transmission Fluctuations and Localization in Semiconductor Superlattices with a Controlled Degree of Order

    Get PDF
    We study both analytically and numerically phonon transmission fluctuations and localization in partially ordered superlattices with correlations among neighboring layers. In order to generate a sequence of layers with a varying degree of order we employ a model proposed by Hendricks and Teller as well as partially ordered versions of deterministic aperiodic superlattices. By changing a parameter measuring the correlation among adjacent layers, the Hendricks- Teller superlattice exhibits a transition from periodic ordering, with alterna- ting layers, to the phase separated opposite limit; including many intermediate arrangements and the completely random case. In the partially ordered versions of deterministic superlattices, there is short-range order (among any NN conse- cutive layers) and long range disorder, as in the N-state Markov chains. The average and fluctuations in the transmission, the backscattering rate, and the localization length in these multilayered systems are calculated based on the superlattice structure factors we derive analytically. The standard deviation of the transmission versus the average transmission lies on a {\it universal\/} curve irrespective of the specific type of disorder of the SL. We illustrate these general results by applying them to several GaAs-AlAs superlattices for the proposed experimental observation of phonon universal transmission fluctuations.Comment: 16-pages, Revte
    corecore