904 research outputs found

    Development of biodegradable, cellulose-based, essential oil and chitosan drug delivery systems for cosmetic mask applications

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    The goal of this research was the development of cellulose-based biodegradable drug delivery systems solutions for cosmetic mask applications. Cellulose-based materials derived from natural renewable sources provide a sustainable alternative to nonwoven cosmetic masks derived from nondegradable fossil-based raw materials. An experimental design was executed to assemble the 3D cellulose fibres matrix and the water in oil emulsion comprising the active molecules from Mentha piperita L. Two types of biopolymeric additives were used, one derived from a nano/micro fibrillated cellulose pulp and another one including chitosan. A 3D computational simulation study was performed to enhance porosity and strength properties. The results indicated that the cosmetic face mask optimized prototypes, made from a biodegradable 3D matrix of cellulose fibres and active molecules, are suitable for dermic usePostprint (published version

    Organic farming in northeast of Portugal: effects of soil fertility management on DM yield and nutrients composition of pastures

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    The aim of this work was to evaluate the effect of six types of soil fertility management: no fertiliser (NF), lime inputs (Ca), mineral fertilisation combined with hming (CaP (lime and phosphorous), CaPB (lime, phosphorous and boron), manure (M), and manure+lime+mineral fertilisation (MCaPB), and two types of pasture (unsown and sown) on DM yield, botanical composition and nutrients content of pasture during two years of study. DM yield was significantly increased when plots were fertilised with manure (M and MCaPB), which also improved the proportion of legumes, mainly in the sown pasture

    Synthesis of titanate nanofibers co-sensitized with ZnS and Bi2S3 nanocrystallites and their application on pollutants removal

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    The synthesis of nanocomposite materials combining titanate nanofibers (TNF) with nanocrystalline ZnS and Bi2S3 semiconductors is described in this work. The TNF were produced via hydrothermal synthesis and sensitized with the semiconductor nanoparticles, through a single-source precursor decomposition method. ZnS and Bi2S3 nanoparticles were successfully grown onto the TNF's surface and Bi2S3-ZnS/TNF nanocomposite materials with different layouts were obtained using either a layer-by-layer or a co-sensitization approach. The samples' photocatalytic performance was first evaluated through the production of the hydroxyl radical using terephthalic acid as probe molecule. All the tested samples show photocatalytic ability for the production of this oxidizing species. Afterwards, the samples were investigated for the removal of methylene blue. The nanocomposite materials with best adsorption ability for the organic dye were the ZnS/TNF and Bi2S3ZnS/TNF. The removal of the methylene blue was systematically studied, and the most promising results were obtained considering a sequential combination of an adsorption-photocatalytic degradation process using the Bi2S3ZnS/TNF powder as a highly adsorbent and photocatalyst material.Comment: 26 pages, 10 figure

    Diagnosis Of Secondary Caries In Esthetic Restorations: Influence Of The Incidence Vertical Angle Of The X-ray Beam

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    The aim of this study was to evaluate the accuracy on the diagnosis of secondary caries-like lesions simulated on esthetic restorations of different materials, changing the incidence vertical angle (IVA) of the x-ray beam. Twenty human teeth received MOD inlay preparations. In the experimental group (n=10), a round cavity was made in the floor of the proximal box to simulate the caries-like lesion. All teeth were restored with 3 composite resins (Charisma, Filtek-Z250 and TPH-Spectrum) at 3 moments. Two radiographic images were acquired with 0° and 10° IVA. Ten observers evaluated the images using a 5-point confidence scale. Intra- and interobserver reliability was analyzed with the Interclass Correlation Coefficient and the diagnostic accuracy was evaluated using the area under the ROC curve (Az), Friedman test and Wilcoxon test (α=0.05). Higher accuracy values were obtained with 10° IVA (Az=0.66, Filtek- Z250>Az=0.56, TPH-Spectrum) compared to 0° (Az=0.55, Charisma>Az=0.37, TPH-Spectrum), though without statistically significant difference (p>0.05). The detection of secondary caries-like lesions simulated on esthetic restorations of different materials suffered no negative influence by changing the IVA of the x-ray beam.222129133Levin, L., Coval, M., Geiger, S.B., Cross-sectional radiographic survey of amalgam and resin-based composite posterior restorations (2007) Quintessence Int, 38, pp. 511-514Haak, R., Wicht, M.J., Hellmich, M., Noack, M.J., Detection of marginal defects of composite restorations with conventional and digital radiographs (2002) Eur J Oral Sci, 110, pp. 282-286Kirkevang, L.L., Vaeth, M., Wenzel, A., Prevalence and incidence of caries lesions in relation to placement and replacement of fillings: A longitudinal observational radiographic study of an adult Danish population (2009) Caries Res, 43, pp. 286-293Newman, B., Seow, W.K., Kazoullis, S., Ford, D., Holcombe, T., Clinical detection of caries in the primary dentition with and without bitewing radiography (2009) Austr Dent J, 54, pp. 23-30Anbiaee, N., Mohassel, A.R., Imanimoghaddam, M., Moazzami, S.M., A comparison of the accuracy of digital and conventional radiography in the diagnosis of recurrent caries (2010) Contemp Dent Pract, 11, pp. 25-32Nair, M.K., Tyndall, D.A., Ludlow, J.B., May, K., Ye, F., The effects of restorative material and location on the detection of simulated recurrent caries. A comparison of dental film, direct digital radiography and tuned aperture computed tomography (1998) Dentomaxillofac Radiol, 27, pp. 80-84van der Stelt, P.F., Ruttiman, U.E., Webber, R.L., Heemstra, P., In vitro study into the influence from x-ray beam angulation on the detection of artificial caries defects on interproximal radiographs (1989) Caries Res, 23, pp. 334-341Tveit, A.B., Espelid, I., Erickson, R.L., Glasspoole, E.A., Vertical angulation from X-ray beam and radiographic diagnosis of secondary caries (1991) Community Dent Oral Epidemiol, 19, pp. 333-335Akarslan, Z.Z., Akdevelioǧlu, M., Güngör, K., Erten, H., A comparison of the diagnostic accuracy of bitewing, periapical, unfiltered and filtered digital panoramic images for approximal caries detection in posterior teeth (2008) Dentomaxillofac Radiol, 37, pp. 458-463Sabbagh, J., Vreven, J., Leloup, G., Radiopacity of resin-based materials measured in film radiographs and storage phosphor plate (Digora) (2004) Oper Dent, 29, pp. 677-684Dental resin based restorative materials, 6 (10), pp. 1985-1985. , ISO:DP 4049, International standards organization (Draft Proposal), clauseMagalhães, C.S., Freitas, A.B., Moreira, A.N., Ferreira, E.F., Validity of staining and marginal ditching as criteria for diagnosis of secondary caries around occlusal amalgam restorations: An in vitro study (2009) Braz Dent J, 20, pp. 307-313Ergücü, Z., Türkün, L.S., Onem, E., Güneri, P., Comparative radiopacity of six flowable resin composites (2010) Oper Dent, 35, pp. 436-440Lasko, T.A., Bhagwat, J.G., Zou, K.H., Ohno-Machado, L., The use of receiver operating characteristic curves in biomedical informatics (2005) J Biomed Inform, 38, pp. 404-415Diniz, M.B., Rodrigues, J.A., Neuhaus, K.W., Cordeiro, R.C., Lussi, A., Influence of examiner's clinical experience on the reproducibility and accuracy of radiographic examination in detecting occlusal caries (2010) Clin Oral Investig, 14, pp. 515-523Zoellner, A., Diemer, B., Weber, H.P., Stassinakis, A., Gaengler, P., Histologic and radiographic assessment of caries-like lesions localized at the crown margin (2002) J Prosthet Dent, 88, pp. 54-59Ferreira, R.I., Haiter-Neto, F., Tabchoury, C.P., de Paiva, G.A., Bóscolo, F.N., Assessment of enamel demineralization using conventional, digital, and digitized radiography (2006) Braz Oral Res, 20, pp. 114-119Peker, I., Toraman Alkurt, M., Altunkaynak, B., Film tomography compared with film and digital bitewing radiography for proximal caries detection (2007) Dentomaxillofac Radiol, 36, pp. 495-49

    The compound Poisson limit ruling periodic extreme behaviour of non-uniformly hyperbolic dynamics

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    We prove that the distributional limit of the normalised number of returns to small neighbourhoods of periodic points of non-uniformly hyperbolic dynamical systems is compound Poisson. The returns to small balls around a fixed point in the phase space correspond to the occurrence of rare events, or exceedances of high thresholds, so that there is a connection between the laws of Return Times Statistics and Extreme Value Laws. The fact that the fixed point in the phase space is a repelling periodic point implies that there is a tendency for the exceedances to appear in clusters whose average sizes is given by the Extremal Index, which depends on the expansion of the system at the periodic point. We recall that for generic points, the exceedances, in the limit, are singular and occur at Poisson times. However, around periodic points, the picture is different: the respective point processes of exceedances converge to a compound Poisson process, so instead of single exceedances, we have entire clusters of exceedances occurring at Poisson times with a geometric distribution ruling its multiplicity. The systems to which our results apply include: general piecewise expanding maps of the interval (Rychlik maps), maps with indifferent fixed points (Manneville-Pomeau maps) and Benedicks-Carleson quadratic maps.Comment: To appear in Communications in Mathematical Physic

    Implante transcateter valve‐in‐valve para disfunção de biopróteses cirúrgicas aórticas

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    RESUMOIntroduçãoEstudos recentes têm demonstrado a eficácia do implante transcateter valve‐in‐valve para o tratamento de disfunção de biopróteses em pacientes de alto risco cirúrgico. Apresentamos nossa experiência inicial com o implante valve‐in‐valve.MétodosCaracterizamos o perfil clínico, ecocardiográfico e do procedimento, e reportamos os resultados de médio prazo de pacientes com disfunção de bioprótese submetidos a implante valve‐in‐valve em posição aórtica.ResultadosIncluímos sete pacientes do sexo masculino, com idade de 72,6 ± 10,0 anos. O escore STS foi 9,6 ± 10,5%, e o EuroSCORE logístico foi 22,7 ± 14,7%. Três pacientes apresentavam dupla disfunção; dois tinham insuficiência; e dois exibiam estenose isolada. A via transfemoral foi utilizada em seis casos, e a transapical, em um caso. Os dispositivos implantados incluíram as próteses Sapien XT (n = 5) e CoreValve (n = 2). O sucesso do procedimento foi obtido em seis (85,7%) casos. Após o procedimento, o gradiente médio reduziu‐se de 38,2 ± 9,6mmHg para 20,9 ± 5,9mmHg, e a área valvar elevou‐se de 1,2 ± 0,4cm2 para 1,5 ± 0,5cm2. Ao final de 1 ano, não ocorreram óbitos e nem outros desfechos adversos significativos; 80% dos pacientes encontravam‐se em classe funcional NYHA I/II. Os gradientes transvalvares e a área valvar permaneceram inalterados nesse período.ConclusõesO procedimento valve‐in‐valve foi eficaz na maioria dos pacientes de alto risco cirúrgico com disfunção de bioprótese. Quando realizado em pacientes bem selecionados, resulta em desfechos clínicos e hemodinâmicos satisfatórios.ABSTRACTBackgroundRecent studies have demonstrated the efficacy of the transcatheter valve‐in‐valve implantation for the treatment of bioprosthesis dysfunction in high‐risk surgical patients. This study presents the initial experience with valve‐in‐valve implantation.MethodsClinical, echocardiographic, and procedural profiles were characterized, and the mid‐term results of patients with surgical bioprosthesis dysfunction submitted to valve‐in‐valve implantation in the aortic position were reported.ResultsSeven male patients were included, aged 72.6 ± 10.0 years. The STS score was 9,6 ± 10,5%, and the logistic EuroSCORE was 22.7 ± 14.7%. Three patients had combined aortic bioprosthesis failure; two had isolated regurgitation; and two had isolated stenosis. The transfemoral access was used in six cases, and the transapical access in one case. Implanted devices included Sapien XT (n = 5) and CoreValve (n = 2) prostheses. Procedural success was achieved in six (85.7%) cases. After the procedure, the mean gradient decreased from 38.2 ± 9.6mmHg to 20.9 ± 5.9mmHg, and the valve area increased from 1.2 ± 0.4cm2 to 1.5 ± 0.5cm2. After 1 year, there were no deaths and no other significant adverse outcomes; 80% of patients were in NYHA functional class I/II. The transvalvular gradients and valve area remained unchanged in this period.ConclusionsThe valve‐in‐valve procedure was effective in most high‐risk surgical patients with bioprosthesis dysfunction. When performed in well‐selected patients, it results in satisfactory clinical and hemodynamic outcomes

    Euclidean Approach to the Entropy for a Scalar Field in Rindler-like Space-Times

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    The off-shell entropy for a massless scalar field in a D-dimensional Rindler-like space-time is investigated within the conical Euclidean approach in the manifold C_\be\times\M^N, C_\be being the 2-dimensional cone, making use of the zeta-function regularisation. Due to the presence of conical singularities, it is shown that the relation between the zeta-function and the heat kernel is non trivial and, as first pointed out by Cheeger, requires a separation between small and large eigenvalues of the Laplace operator. As a consequence, in the massless case, the (naive) non existence of the Mellin transform is by-passed by the Cheeger's analytical continuation of the zeta-function on manifold with conical singularities. Furthermore, the continuous spectrum leads to the introduction of smeared traces. In general, it is pointed out that the presence of the divergences may depend on the smearing function and they arise in removing the smearing cutoff. With a simple choice of the smearing function, horizon divergences in the thermodynamical quantities are recovered and these are similar to the divergences found by means of off-shell methods like the brick wall model, the optical conformal transformation techniques or the canonical path integral method.Comment: 17 pages, LaTex. A sign error corrected and few comments adde

    Identifying and explaining the farming system composition of agricultural landscapes: The role of socioeconomic drivers under strong biophysical gradients

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    In mountain landscapes, agricultural abandonment is taking place in the most vulnerable areas, while intensification increases in the most productive lands. These contrasting processes, which have different impacts on biodiversity and ecosystem services (BES), are related to changes in the farming system component of these landscapes. Farming systems are identified based on farmer’s decisions on, for example, type of crop and level of fertilizers, which represent the descriptors of farming systems and can be grouped into several dimensions (e.g. land use and intensity). Since obtaining this data at farm-level is often difficult, an alternative is to study the spatial combinations of farming systems at parish-level, i.e., Farming System Mixes (FSM), relying on agricultural census data. Other biophysical (e.g. climate, soil) and socioeconomic (e.g. labour, farmer’s age) variables, independent of farmers' decisions, represent the exogenous drivers of these decisions. The separation between descriptors and drivers is important to improve knowledge about what drives farmers' decisions regarding farming system choice, as these choices are often the focus of policies aiming the support of BES. In this study, we explored the underlying drivers of FSM and assessed the role of socioeconomic drivers, main target for policy makers, in a context of strong biophysical gradients. Biophysical drivers emerge as those that primarily discriminate between the FSM located in different topographic positions (valleys, mountains and plateau). In the situations where there is a greater range of productive choices available for farmers, such as in valleys, socioeconomic drivers assume a preponderant role on farming system choiceinfo:eu-repo/semantics/publishedVersio
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