Development and in vitro evaluation of coated pellets containing chitosan to potential colonic drug delivery

In this work pellets containing chitosan for colonic drug delivery were developed. The influence of the polysaccharide in the pellets was evaluated by swelling, drug dissolution and intestinal permeation studies. Drug-loaded pellets containing chitosan as swellable polymer were coated with an inner layer of Kollicoat® SR 30 D and an outer layer of the enteric polymer Kollicoat® MAE 30 DP in a fluidized-bed apparatus. Metronidazole released from pellets was assessed using Bio-Dis dissolution method. Swelling, drug release and intestinal permeation were dependent on the chitosan and the coating composition. The drug release data fitted well with the Weibull equation, indicating that the drug release was controlled by diffusion, polymer relaxation and erosion occurring simultaneously. The film coating was found to be the main factor controlling the drug release and the chitosan controlling the drug intestinal permeation. Coated pellets containing chitosan show great potential as a system for drug delivery to the colon. © 2012 Elsevier Ltd.

Application of a bounded upwinding scheme to complex fluid dynamics problems

This paper is concerned with an overview of upwinding schemes, and further nonlinear applications of a recently introduced high resolution upwind differencing scheme, namely the ADBQUICKEST [V.G. Ferreira, F.A. Kurokawa, R.A.B. Queiroz, M.K. Kaibara, C.M. Oishi, J.A.Cuminato, A.F. Castelo, M.F. Tomé, S. McKee, assessment of a high-order finite difference upwind scheme for the simulation of convection-diffusion problems, International Journal for Numerical Methods in Fluids 60 (2009) 1-26]. The ADBQUICKEST scheme is a new TVD version of the QUICKEST [B.P. Leonard, A stable and accurate convective modeling procedure based on quadratic upstream interpolation, Computer Methods in Applied Mechanics and Engineering 19 (1979) 59-98] for solving nonlinear balance laws. The scheme is based on the concept of NV and TVD formalisms and satisfies a convective boundedness criterion. The accuracy of the scheme is compared with other popularly used convective upwinding schemes (see, for example, Roe (1985) [19], Van Leer (1974) [18] and Arora & Roe (1997) [17]) for solving nonlinear conservation laws (for example, Buckley-Leverett, shallow water and Euler equations). The ADBQUICKEST scheme is then used to solve six types of fluid flow problems of increasing complexity: namely, 2D aerosol filtration by fibrous filters; axisymmetric flow in a tubular membrane; 2D two-phase flow in a fluidized bed; 2D compressible Orszag-Tang MHD vortex; axisymmetric jet onto a flat surface at low Reynolds number and full 3D incompressible flows involving moving free surfaces. The numerical simulations indicate that this convective upwinding scheme is a good generic alternative for solving complex fluid dynamics problems. © 2012.

Filamentous fungi vectored by ants (Hymenoptera: Formicidae) in a public hospital in north-eastern Brazil

Background: The increase in opportunistic fungal infections has led to the search for putative sources of contamination in hospital environments. Aim: Ants in a public hospital in Itabuna, north-eastern Brazil were examined for carriage of filamentous fungi. Methods: During a year-long survey, ants from different hospital areas were sampled. Preference was given to locations where it was possible to observe ants actively foraging. The fungi found on the ants' integument were cultured and identified. Findings: A total of 106 ant workers belonging to 12 species in 11 genera were collected. A total of 47 fungal strains was isolated from 40% of the ants (. N = 42). We found 16 fungal species in 13 genera associated with the ant workers. The prevalent fungal genera were . Aspergillus, . Purpureocillium and . Fusarium. The ants . Tapinoma melanocephalum, . Paratrechina longicornis and . Pheidole megacephala were associated with six fungal genera; and four genera of fungi were associated with . Solenopsis saevissima workers. Fungal diversity was higher in the following hospital areas: nursery, hospital beds, breastmilk bank and paediatrics. Conclusion: Ants act as carriers of soil and airborne fungal species, and ant control in hospital areas is necessary to prevent the dissemination of such micro-organisms. © 2012 The Healthcare Infection Society.

The use of polylactic and polyglycolic copolymer biomaterial in a pre-clinical model of compromised primary stability

Aim Primary implant stability can be compromised by overdrilling of the implant bed. Filling the gap between the implant and the bone with a highly viscous copolymer of polylactic and polyglycolic acid (PLA/PGA) might stabilize the implant and thus supply osseointegration. The aim of this study was to evaluate implants installed in overdrilled beds associated with PLA/PGA in rats tibia model by means of removal torque test and fluorochrome analysis. Materials and methods For this experiment two groups were selected: in the test group 0.4 mm overdrilled defects (2.0 in diameter and 3 mm long ) were produced in the right tibia of seven rats and implants were placed covered with PLA/PGA biomaterial to fill the gap; the control group was not overdrilled and the implants were placed without the biomaterial. Implants of 1.6 mm in diameter and 3 mm long where placed into all defects. Calcein, alizarin and oxytetracyclin were injected at 7, 15 and 21 postoperative days, respectively, and the animals were sacrificed at 35 postoperative day. Results The results showed that all the implants achieved osseointegration. There were no statistical significance differences in torque-reverse and fluorocrome analysis (P>0.05). Conclusion We can conclude that overdrilled defects filled with PLA/PGA did not disturb osseointegration in this experimental model. © ARIESDUE.

Origin and impact of the oldest metazoan bioclastic sediments

The emergence of soft-bodied metazoans and the radiation of the earliest skeletal organisms substantially changed the ecological dynamics of Ediacaran environments, leading to the genesis of biogenic hard-part deposits for the fi rst time in Earth's history. The impact of bioclast origin on sedimentary processes is analyzed herein, focusing on the sedimentology and taphonomy of shell concentrations dominated by the Ediacaran index fossil Cloudina from the Itapucumí Group, Paraguay. Skeletal concentrations include both dense accumulations of parautochthonous, disarticulated specimens (Type 1 deposits) and in situ specimens preserved as loosely packed assemblages (Type 2 deposits). At that time, Cloudina was the critical source of durable biomineralized hard parts in an environment nearly free of other bioclasts. The simple fabric and geometry of these accumulations are typical of Cambrian-style shell beds. Despite their Precambrian age, these deposits indicate that the establishment of the Phanerozoic style of marine substrates and preservation in early shell beds was determined more by the acquisition of hard parts than by environmental changes. © 2013 Geological Society of America.

Análise das tensões de água no solo cultivado com morangueiro sob poda

Strawberry yield and quality was evaluated after drastic pruning (second cycle), under different soil water tensions, drip irrigation. The experiment was conducted on beds at a greenhouse, located at Engineering Department, Federal University of Lavras (UFLA), from April to December of 2010. An experimental design was in randomized blocks with three replicates. The treatments were composed of six different soil water tension, 15, 25, 35, 45, 55 e 70 kPa. Results obtained allowed to verify that to higher values of: total and commercial fresh weight of fruits per plant, total and commercial number fruits per plant and total and commercial yield, it is necessary to irrigate when soil water tension gets approximately to 15 kPa, at 0.15 m deep. Commercial average fruit mass and noncommercial fresh weight of fruits per plant, were not reduced under different soil water tensions applied.

Energetic, ecologic and fluid-dynamic analysis of a fluidized bed gasifier operating with sugar cane bagasse

This work aims to study the thermodynamic, ecological and fluid-dynamic aspects of a circulating fluidized bed gasifier using sugar cane bagasse as biomass, in order to estimate a model of its normal operation. In the initial stage was analysed the composition of biomass selected (sugar cane bagasse) and its lower heating value (LHV) was calculated. The energy balance of the gasifier was done, being the volumetric flow of air, synthesis gas and biomass estimated. Also the power produced by this gasifier was theoretically estimated. Then the circulating fluidized bed gasifier was designed for operation with approximately 100 kg/h of processed biomass. Cross-sectional area of the reactor, feeder size, diameter of the exit zone of the gases and minimum height of the expanded bed were selected. Some bed gasifier hydrodynamic factors were also studied. The minimum fluidization velocity, fluidization terminal velocity, and average fluidizing velocity were calculated, in order to understand the fluid-dynamic behaviour of gasification of this fuel. It was obtained a theoretical model that can support a possible prototype of circulating fluidized bed gasifier biomass. Finally, there were studied the ecological aspects of the gasifier, through an overall methodology. Ecological efficiencies were estimated for two scenarios: first considering the carbon cycle and thereafter disregarding the carbon cycle. In both cases, it can be proved the ecological viability of the project. © 2013 Elsevier Ltd. All rights reserved.

A C2-continuous high-resolution upwind convection scheme

A bounded upwinding scheme for numerical solution of hyperbolic conservation laws and Navier-Stokes equations is presented. The scheme is based on convection boundedness criterion and total variation diminishing stability criteria and developed by employing continuously differentiable functions. The accuracy of the scheme is verified by assessing the error and observed convergence rate on 1-D benchmark test cases. A comparative study between the new scheme and conventional total variation diminishing/convection boundedness criterion-based upwind schemes to solve standard nonlinear hyperbolic conservation laws is also accomplished. The scheme is then examined in the simulation of Newtonian and non-Newtonian fluid flows of increasing complexity; a satisfactory agreement has been observed in terms of the overall behavior. Finally, the scheme is used to study the hydrodynamics of a gas-solid flow in a bubbling fluidized bed. © 2013 John Wiley & Sons, Ltd.

Stagnant effective thermal conductivity of agro-industrial residues for solid-state fermentation

The stagnant effective thermal conductivities (K0) of sugar cane bagasse (SCB), wheat bran (WB), orange pulp and peel (OPP) and their combination (weight proportion 1:2:2 SCB/OPP/WB) were obtained using the line heat source method. These solid materials were applied to pectinase production via solid-state fermentation. The moisture content ranged from 4 to 80% (w.b.). A conduction mechanism through the porous media was observed, along with conduction through a liquid film and contact thermal resistance between the samples and the probe. K0 was low for intermediate moisture contents and approached the molecular conductivity of water for high moisture contents. © 2013 Copyright Taylor and Francis Group, LLC.

Efeitos fisiológicos da piraclostrobina em plantas de feijão (Phaseolus vulgaris L.) condicionado sob diferentes tensões de água no solo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Proposta de metodologia para o gerenciamento de fonte radioativa e estimativa de dose efeiva em pacientes submetidos à terapia com iodeto de sódio I-131

Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

Desenvolvimento de critério objetivo para a sinalização da ingestão alimentar deficiente de paciente hospitalizado

Pós-graduação em Alimentos e Nutrição - FCFAR

Aplicação do copolímero PLA/PGA adicionado ao fosfato de cálcio ao redor de implantes osseointegráveis instalados sem estabilidade primária em tíbia de coelhos: estudo biomecânico, histométrico e imunoistoquímico

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação comparativa da viabilidade celular imediata após osteotomia para implantes com fresas e piezocirurgia em tíbias de coelhos: análise imunoistoquímica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação do copolímero de ácido polilático e poliglicólico ao redor de implantes osseointegráveis sem estabilidade primária: análise biomecânica, histométrica e imunoistoquímica em coelhos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)