305 research outputs found
Strain field analysis of cancellous bone under compression by image correlation
Experimental mechanical analysis of cancellous bone has been performed to capture the global strain field of
specimens under compression. One major objective is to assess the test procedure and obtain the cancellous bone
mechanical properties. Now a day, several techniques are available for the experimental measurement of the field
displacement. Among them, the Cross-Correlation is one of most simple’s techniques and can be applied to several studies cases. Based on the correlation of random speckle pattern between two images, the spatial displacement fields can be
accessed. A simple digital camera or video recorder can be used without special light to capture the surface intensity pattern
in each instant. If several images are taken during a test loading, the displacement field can be fallowed and subsequently
the strain can be obtain by the spatial differentiation. Because of random surface pattern, the image can be divided in small
areas, each of them pattern independent. By cross-correlating each of one between the two images, the relative displacement is obtained
Antimicrobial activity of endophytic fungi from olive tree leaves
In this study, the antimicrobial potential of three fungal endophytes from leaves of Olea europaea L. was evaluated and the host plant extract effect in the antimicrobial activity was examined. The volatile compounds produced by endophytes were identified by GC/MS and further correlated with the antimicrobial activity. In potato dextrose agar, both Penicillium commune and Penicillium canescens were the most effective inhibiting Gram-positive and -negative bacteria (up to 2.7-fold compared to 30 µg/mL chloramphenicol), whereas Alternaria alternata was most effective inhibiting yeasts (up to 8.0-fold compared to 25 μg/mL fluconazole). The presence of aqueous leaf extract in culture medium showed to induce or repress the antimicrobial activity, depending on the endophytic species. In the next step, various organic extracts from both A. alternata mycelium and cultured broth we re prepared; being ethyl acetate extracts displayed the widest spectrum of anti-microorganisms at a minimum inhibitory concentration ≤0.095 mg/mL. The volatile composition of the fungi that displayed the highest (A. alternata) and the lowest (P. canescens) antimicrobial activity against yeasts revealed the presence of six volatiles, being the most abundant components (3-methyl-1-butanol and phenylethyl alcohol) ascribed with antimicrobial potentialities. Overall the results highlighted for the first time the antimicrobial potential of endophytic fungi from O. europaea and the possibility to be exploited for their antimicrobial agents. Graphical Abstract: [Figure not available: see fulltext.]This work is funded by FEDER funds
through COMPETE (Programa Operacional Factores de Competitividade)
and by national funds by FCT (Fundação para a Ciência
e a Tecnologia) in the framework of the project “EndoBio—Isolation
and screening of endophytic fungi for biological control of olive
against Colletotrichum acutatum and Verticillium dahliae” (PTDC/
AGR-PRO/4354/2012).info:eu-repo/semantics/publishedVersio
Systemic release of volatiles by Brassica oleracea var. acephala induced by Pieris brassicae predation.
Pieris brassicae is a specialist on crucifers and its interactions with some of its host plants have
been increasingly studied given their importance in pest management, chemical ecology and
entomology. Plants are known to respond to insect attack by releasing volatiles that can either
warn neighbour plants to the presence of a predator or attract insect parasitoids, thus reducing
the attack efficiency. The influence of P. brassicae feeding on Brassica oleracea L. var. acephala
(kale) was investigated, namely, its effect in the volatiles released by the plant through time.
Substantial differences, mainly quantitative, were found between the volatiles composition of B.
oleracea var. acephala before the attack and after insect feeding. More than 40 compounds were
found, between terpenes (monoterpenes and sesquiterpenes) and lipoxygenase pathway byproducts
(alcohols and aldehydes), ketones, norisoprenoids, among others. After insect attack,
monoterpenes like limonene, eucalyptol, camphor and caryophyllene increased noticeably.
These compounds have been regarded as markers in local tissue responses and in this study an
increase in their concentration was detected at 1 and 4 hours after feeding, with subsequent
reduction after 8 hours. Menthol, menthone, phenol and sabinene were found only in the time
following the attack. A considerable increase in hexenyl acetate, a well known semiochemical,
was also found, with this compound being the major peak in all experiments, rising with time.
These findings provide further knowledge of the ecological interactions between these two
species and, given the chemical diversity of these matrices, they may constitute a good source
of health promoting compounds.Fundação para a Ciência e Tecnologia for financial support (PTDC/AGRAAM/
64150/2006). F. Fernandes (SFRH/BD/37963/2007
Metabolic fate of dietary volatile compounds in Pieris brassicae
In this work, the evolution of the qualitative and quantitative profile of the volatile fraction of Pieris brassicae
after feeding on Brassica oleracea var. acephala (kale) was monitored through time. HS-SPME/GC-MS was
applied to both the host plant and the living insect and its excrements. A total of seventy seven compounds
(lipoxygenase pathway by-products, nitrogen compounds, norisoprenoids, sulphur compounds, terpenes,
among others) were identified. Thirty eight compounds were identified in insect after 2 h of starvation and
forty eight compounds in excrements. Qualitative and quantitative changes were detected along time.
Dimethyldisulfide, dimethyltrisulfide, limonene and eugenol were major compounds for all analysed times in
both matrices, being limonene an important compound in insect after starvation. The accumulation by
P. brassicae of some compounds, such as limonene, was verified, suggesting a mechanism by which the insect
can take benefit from bioactive constituents from the diet. Along with accumulation, complete excretion of
some compounds, including nitrogen bearing compounds, by-products of glucosinolates was detected. These
results reflect one of the strategies used to overcome plant barriers, namely detoxification of toxic
compounds. The findings contribute to the knowledge of the metabolization of the volatile compounds in
insects and contribute to the body of knowledge of this ecologic system.FC
Determination of low molecular weight volatiles in Ficus carica using HS-SPME and GC/FID
Ficus carica L. is one of the earliest cultivated fruit trees, having an important consumption in Mediterranean
countries. In this work, the volatile compound profiles of two characteristic Portuguese white varieties
(‘‘Pingo de Mel” and ‘‘Branca Tradicional”) was determined by HS-SPME and GC/FID. Leaves, pulps
and peels, submitted to freezing and lyophilisation treatments, were analysed.
The two varieties presented a similar profile composed of eight volatile compounds: acetaldehyde,
ethyl acetate, methanol, ethanol, hexanal, limonene, (E)-2-hexenal and octanal. The total volatile content
was different among the vegetal materials, following the order leaves > peels > pulps. Methanol and ethanol
are the major compounds in all samples.
The developed procedure revealed to be rapid, sensitive, reproducible and accurate. The detection limit
values were low, and the method precise. The recovery values for acetaldehyde, ethyl acetate, methanol
and ethanol were generally high, suggesting that it will be most suitable for compounds with low molecular
weight. Due to its rapidity and low cost, this technique can be useful in the quality control of fig fruit
and leaves
Influencia de las condiciones de almacenaje en la plasticidad y la liberación de Fentiazac a partir de una formulación tópica
In this work we studied the influence of the plasticity increasing on the release of an AINE [Fentiazac] incorporated in a gel, in function of the time and the temperature of storage. From the reological and in vítro release assays, using artificial epidermic membrane- (SARTORIUS), we concluded that those parameters have some influence in the reological behaviour of the product and in the anti-inflamatory release.En el presente trabajo se ha estudiado la influencia del aumento de la plasticidad en la liberación de un anti-inflamatorio no esteroideo [Fentluzac] vehículado en gel, en función del tiempo y temperatura de almacenaje. A través de ensayos reolígicos y de liberación ín vítro utilizando membranas epidérmicas artificiales (SARTORIUS) se concluye que es los dos parámetros (tiempo y temperatura de almacenaje) influyen en el comportamiento reológico del producto y, consecuentemente, en la liberación del anti-inflamatorio
Actors' perception on future wood production in a cross-border amazonian region: challenges for a sustainable production.
We conducted a study in a cross-border region of Amazonia to analyze the future role of natural forests in producing wood products. French Guiana and the state of Amapa are sharing similar geographical properties. A predominant area of these two territories are dominated by undisturbed tropical forests. In both regions, over 70% of forest areas is under public ownership. Currently the forestry sector in both regions do not have a key role in local economies, with low legal wood production in French Guiana (75 000 m3) as well as in Amapa (around 120 000 m3). Although in Amapá there is a high level of illegality in the sector (85%). In French Guiana and Amapa, forestry activities might represent an economical opportunity to promote endogenous development. The forest sector, including private and public actors, will face strategic choices to respond to increasing demand in wood supply for the coming decades. Strategic choices, based on strong political decisions, include the volume of wood to be produced locally, type of actors involved (i.e. communities, private companies), type of production (timber vs fuelwood) and origin of wood (plantation vs natural forest). Based on a prospective approach, we identified various scenarios, for each region, to reach the wood supply by 2045. First, we interviewed key actors of the forestry sector to obtain the view from their perspective. Second we selected the key variables to construct the scenarios and validated the resulting scenarios through a discussion with all actors. The scenarios identified in French Guiana had the implementation of tree plantation with local species as alternative to natural forest management, while in Amapa they focused on forest management associated with public policy and social factors. These scenarios are providing a framework of discussions that could help actors to focus on long term and to imagine the likely impact of current policy choices on the socioeconomy and conservation of natural forests.Na publicação consta: Castro Euler, A. M; Guedes, M.; Gazel Yared, J. A.; Doff Sotta, E. IUFRO17-2755
Raman scattering studies of monohydrated L-asparagine
Polarized first-order Raman scattering studies at 300 K were carried out in L-asparagine monohydrate crystal in order to obtain the general assignment of its phonon spectra. A careful analysis of the vibrational spectra shows that the assignment of the fundamental vibrational modes can be done on the basis of amino, carboxilic and water groups vibrations, and correlations with previous data reported for other amino acids. However, some vibrations were correctly assigned from the study of its temperature - dependence behavior performed in the range 10 - 300 K. The assignment proposed cofirm the zwitterionic structure of L-asparagine monohydrate crystal.380387Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
Industry/University collaboration in product focussed œnological research in Portugal - the SOGRAPE / UCP ESB partnership 1995 - 1998
A innovative model of collaboration between a wine company and a university research
group is presented. A protocol was established as a response to the perceived need to, on the part of the university, (i) focus research on specific scientific bottlenecks which would have a real impact in the producing industry and, on the part of the company, (ii) to have access to
the scientific capacity to conduct in-depth studies to approach specific technical challenges. A closely managed programme was jointly established and the major characteristics are presented here together with the main results obtained during the first 2 and a half years of operation
Inactivation of E. coli mediated by high surface area CuO accelerated by light irradiation >360nm
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