1,023 research outputs found
Antioxidant,antimicrobial and toxicological properties of Schinus molle L. essential oils
Ethnopharmacological relevance: Schinus molle L. has been used in folk medicine as antibacterial, antiviral, topical antiseptic, antifungal, antioxidant, anti-inflammatory, anti-tumoural as well as antispasmodic and analgesic; however, there are few studies of pharmacological and toxicological properties of S. molle essential oils.
Aim of the study: The aim of this study was to evaluate the antioxidant and antimicrobial activities of S. molle leaf and fruit essential oils, correlated with their chemical composition and evaluate their acute toxicity.
Materials and methods: The chemical composition of S. molle leaf and fruit essential oils were evaluated by GC-FID and GC-MS. Antioxidant properties were determined using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical and β-carotene/linoleic acid methods. Antimicrobial properties were evaluated by the agar disc diffusion method and minimal inhibitory concentration assay. Toxicity in Artemia salina and acute toxicity with behavioural screening in mice were evaluated.
Results: The dominant compounds found in leaf and fruit essential oils (EOs) were monoterpene hydrocarbons, namely -phellandrene, β-phellandrene, β-myrcene, limonene and α-pinene. EOs showed low scavenging antioxidant activity by the DPPH free radical method and a higher activity by the β-carotene/linoleic acid method. Antimicrobial activity of EOs was observed for Gram+, Gram– pathogenic bacteria and food spoilage fungi. EOs showed cytotoxicity for Artemia salina and lower toxicity in Swiss mice.
Conclusions: The result showed that EOs of leaves and fruits of S. molle demonstrated antioxidant and antimicrobial properties, suggesting their potential use in food or pharmaceutical industries
Mechanical analysis of PDMS material using biaxial test
Polydimethylsiloxane (PDMS) materials are classified as a silicone and commonly present a hyperelastic behaviour. Many researchers have studied PDMS in recent years, motivated by its applications in the biomedical field. In the present manuscript, a biaxial tensile test performed at different speeds is described. The displacement field for the different experimental test conditions is measured using the digital image correlation technique. Numerical studies were also carried out using the most popular constitutive models, namely Mooney-Rivlin, Yeoh and Ogden, for comparison with the experimental measurements. From the experimental displacement profile taken along the central section of each sample, that this tensile test presents linear behaviour; it is an independent speed test. The same conclusion can be found from the numerical results. The results of the numerical simulation show that they are strongly dependent on the constitutive model of the material. The numerical simulations with the Yeoh model presented the most accurate results for PDMS behaviour. Another important conclusion is that the digital image correlation technique is well suited for the analysis of hyperelastic materials.info:eu-repo/semantics/publishedVersio
Natural extracts from Pterospartum tridentatum at different vegetative stages: extraction yiels, phenolic content and antioxidant activity
The aerial parts of Pterospartum tridentatum, a wild growing species in Portugal used in
traditional medicine and gastronomy, were harvested at different stages (vegetative phase, flowering
phase and beginning of dormancy) in two locations in Portugal (Malcata and Gardunha mountains),
and the respective aqueous extracts have been studied. The influence of the seasonal variation in the
extraction yield, total phenolic content and antioxidant activity was evaluated. The extraction was
carried out in boiling water in consecutive steps. After each step, the aqueous extract was separated
and fresh water was added maintaining the same plant material. The procedure was repeated seven
times, within an overall time period of 180 minutes.
Higher extraction yields were achieved with plant stems collected at the vegetative phases, either from
Malcata or Gardunha regions. The total phenolic content of the extracts from Malcata plants ranged
from 273 mg to 400 mg gallic acid equivalent/g dry matter, which was quite similar to that determined
for extracts from Gardunha (245 to 394 mg gallic acid equivalent/g dry matter). The antioxidant activity
was determined by the radical scavenging activity method using 2,2-diphenyl-1-picrylhydrazyl radical
(DPPH). The greatest radical scavenging activity was observed in the flowers extracts, even though all
extracts produced presented a good antioxidant activity. Furthermore, the antioxidant activity was not
affected by the exposure of the plant material at 100ÂşC for long periods of time (180 min).
The results show that Pterospartum tridentatum has a great potential to be used as a new source of
natural antioxidants for the food industry
Atividade antioxidante e antimicrobiana de extratos de plantas de Pterospartum tridentatum (L.) Willk. in vitro e silvestres
Atividade antioxidante e antimicrobiana de extratos de plantas de Pterospartum tridentatum (L.) Willk. in vitro e silvestres.info:eu-repo/semantics/publishedVersio
Identificação de compostos bioativos em plantas silvestres e plantas in vitro de Pterospartum tridentatum (L.) Willk.
Identificação de compostos bioativos em plantas silvestres e plantas in vitro de Pterospartum tridentatum (L.) Willk.info:eu-repo/semantics/publishedVersio
Research project SerpaFlora: valorization of native microbiota of the Serpa cheese
info:eu-repo/semantics/publishedVersio
Identifying and prioritising services in European terrestrial and freshwater ecosystems
Ecosystems are multifunctional and provide humanity with a broad array of vital services. Effective management of services requires an improved evidence base, identifying the role of ecosystems in delivering multiple services, which can assist policy-makers in maintaining them. Here, information from the literature and scientific experts was used to systematically document the importance of services and identify trends in their use and status over time for the main terrestrial and freshwater ecosystems in Europe. The results from this review show that intensively managed ecosystems contribute mostly to vital provisioning services (e.g. agro-ecosystems provide food via crops and livestock, and forests provide wood), while semi-natural ecosystems (e.g. grasslands and mountains) are key contributors of genetic resources and cultural services (e.g. aesthetic values and sense of place). The most recent European trends in human use of services show increases in demand for crops from agro-ecosystems, timber from forests, water flow regulation from rivers, wetlands and mountains, and recreation and ecotourism in most ecosystems, but decreases in livestock production, freshwater capture fisheries, wild foods and virtually all services associated with ecosystems which have considerably decreased in area (e.g. semi-natural grasslands). The condition of the majority of services show either a degraded or mixed status across Europe with the exception of recent enhancements in timber production in forests and mountains, freshwater provision, water/erosion/natural hazard regulation and recreation/ecotourism in mountains, and climate regulation in forests. Key gaps in knowledge were evident for certain services across all ecosystems, including the provision of biochemicals and natural medicines, genetic resources and the regulating services of seed dispersal, pest/disease regulation and invasion resistance
Measuring in the Early Universe: CMB Temperature, Large-Scale Structure and Fisher Matrix Analysis
We extend our recent work on the effects of a time-varying fine-structure
constant in the cosmic microwave background, by providing a thorough
analysis of the degeneracies between and the other cosmological
parameters, and discussing ways to break these with both existing and/or
forthcoming data. In particular, we present the state-of-the-art CMB
constraints on , through a combined analysis of the BOOMERanG, MAXIMA
and DASI datasets. We also present a novel discussion of the constraints on
coming from large-scale structure observations, focusing in particular
on the power spectrum from the 2dF survey. Our results are consistent with no
variation in from the epoch of recombination to the present day, and
restrict any such (relative) variation to be less than about 4%. We show that
the forthcoming MAP and (particularly) Planck experiments will be able to break
most of the currently existing degeneracies between and other
parameters, and measure to better than percent accuracy.Comment: 11 pages in RevTex4 format. Low-quality figures to comply with arXiv
restrictions (better ones available from the authors). v2: Updated Oklo
discussion, plus other cosmetic changes. Version to appear in Phys Rev
NCESPARC+: an implementation of a SPARC architecture with hardware support to multithreading for the multiplus multiprocessor
NCESP ARC + is an implementation of the SP ARC v: 8 architecture with hardware support to a variable number of thread contexts, which is under development for use within the framework of the Multiplus distributed shared-memory multiprocessor. It is expected to provide an efficient and automatic mechanism to hide the latency of busy-waiting synchronization loops, cachecoherence protocol and remote memory access operations within the Multiplus multiprocessor. NCESPARC + performs context-switching in at most four processor cycles whenever there is an instruction cache miss, a data dependency in relation to the destination operand of a pending load instruction or a busy-waiting synchronization loop. It has a decoupled architecture which allows the main pipeline to process instructions from a given context while the Memory Interface Unit performs memory access operations related to that same context or to any other context. Results of simulation experiments show the impact of some architectural parameters on the NCESPARC + processor performance and demonstrate that the use of multiple thread contexts can e.ffectively produce a much better utilization of the processor when long latency operations are performed In addition, NCESPARC + processor performance with a single context is superior to that of a standard implementation of the SPARC architecture due to its decoupled architecture
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