1,070 research outputs found
Climatic and Physiographic Variables to Evaluate Culex pipiens s.l. Risk and Habitat
This article belongs to the Special Issue on Environmental Management Information SystemsUsing a geographic information system (GIS), the relations between a georeferenced
data set of Culex pipiens s.l . collected in Portugal mainland during
seven years (2006-2012) and meteorological and physiographic parameters
are evaluated. This work is one of the results of a long-term surveillance program
of pernicious insects that act as vectors of various diseases; its focus is
on the possibility of prevention that can be achieved with abundance data.
The focus on Culex pipiens is justified by its abundance and its competence
as a vector for numerous health issues. The cumulative distribution of monthly
captures by each meteorological parameter allows to compute thresholds corresponding
to mosquito massive presence related to 90% of the captures. Using
the weather parameters measured in the network of weather stations across
the country, a monthly average of each parameter of interest (temperature, humidity,
etc.) is computed and an interpolation of the results is made to produce
raster maps corresponding to each month. The previously obtained thresholds
are applied to each map, producing spatial masks with the relevant zones
for each parameter. The intersection of the various masks for each month
shows the most densely populated area of Culex, and the ensemble allows us
to observe the evolution of mosquito presence through the critical season,
which is from May to October at these latitudes. In parallel, mosquito abundance
data are related to physiographic parameters. The relative distribution
of female mosquitoes across land cover types in each month allows identifying
which classes and seasons are most relevant. Orthometric altitude related
to the presence of 90% of the catches shows the limits reached by mosquitoes
in each month. The results are applied to the previously obtained climate envelopes, delimiting critical areas where the level of risk of transmission of the
pathogens for which Culex pipiens is a competent vector is high and countermeasures
should be concentrated, allowing its planning, and targeting on a
monthly basis. The described procedure can be used with other relevant vectors
in any region of the world, whenever abundance data is available.We acknowledge financial support through national funds to Project PTDC/SAU-SAP/119199/2010, and CESAM by FCT/MCTES [UIDP/50017/2020 + UIDB/50017/2020 + LA/P/0094/2020], to MARE by FCT/MCTES (UIDB/04292/2020) and ARNET (LA/P/0069/2020)info:eu-repo/semantics/publishedVersio
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
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 100ºC 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
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
tri-n-butyltin hydride-mediated radical reaction of a 2-iodobenzamide: Formation of an unexpected carbon-tin bond
Leonardo S. Santos. Instituto de QuÃmica de Recursos Naturales, Universidad de Talca, P.O. Box 747, Talca - Chile.The tri-n-butyltin hydride-mediated reaction of methyl 2,3-di-O-benzyl-4-O-trans-cinnamyl -6-deoxy-6-(2-iodobenzoylamino)-a-D-galactopyranoside afforded an unexpected aryltributyltin compound. The structure of this new tetraorganotin(IV) product has been elucidated by 1H, 13C NMR spectroscopy, COSY and HMQC experiments and electrospray ionization mass spectrometry (ESI-MS). The formation of this new compound via a radical coupling reaction and a radical addition-elimination process is discusse
Comprehensive Review on Full Bone Regeneration through 3D Printing Approaches
Over the last decades, the number of work accidents associated with bone fractures has increased leading to a growing concern worldwide. Currently, autografts, allografts, and xenografts are used for bone regeneration. However, their application has associated risks. Tissue engineering (TE) has brought solutions to address these problems, through the production of temporary supports, providing mechanical support to the formation of new bone tissue and biocompatible and biodegradable scaffolds, which allow cell adhesion and proliferation to ensure bone formation. The combination of materials and structure with the technique to be used will directly influence their physical and chemical properties and, consequently, their action in contributing to bone regeneration. Thus, the focus of this chapter is to perform an exhaustive literature review and a critical analysis of the state of the art in bone TE and present a proposal of an optimized temporary support geometry for bone regeneration in case of large bone defects. For this, it was listed and identified the best choice of biomaterials, fabrication method, cell type and their culture conditions (static vs. dynamic), and/or the inclusion of growth factors for the repair of large bone defects
Extractos aquosos de Pterospartum tridentatum L.: teor de compostos fenólicos e actividade antioxidante
Tendo em vista a valorização deste recurso natural, este trabalho tem como principal objectivo a produção de extractos aquosos das partes aéreas da carqueja e a sua caracterização
Praemonitus praemunitus: can we forecast and prepare for future viral disease outbreaks?
Understanding the origins of past and present viral epidemics is critical in preparing for future outbreaks. Many viruses, including SARS-CoV-2, have led to significant consequences not only due to their virulence, but also because we were unprepared for their emergence. We need to learn from large amounts of data accumulated from well-studied, past pandemics and employ modern informatics and therapeutic development technologies to forecast future pandemics and help minimize their potential impacts. While acknowledging the complexity and difficulties associated with establishing reliable outbreak predictions, herein we provide a perspective on the regions of the world that are most likely to be impacted by future outbreaks. We specifically focus on viruses with epidemic potential, namely SARS-CoV-2, MERS-CoV, DENV, ZIKV, MAYV, LASV, noroviruses, influenza, Nipah virus, hantaviruses, Oropouche virus, MARV, and Ebola virus, which all require attention from both the public and scientific community to avoid societal catastrophes like COVID-19. Based on our literature review, data analysis, and outbreak simulations, we posit that these future viral epidemics are unavoidable, but that their societal impacts can be minimized by strategic investment into basic virology research, epidemiological studies of neglected viral diseases, and antiviral drug discovery
The Gaia-ESO Survey: radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk
We study the relationship between age, metallicity, and alpha-enhancement of
FGK stars in the Galactic disk. The results are based upon the analysis of
high-resolution UVES spectra from the Gaia-ESO large stellar survey. We explore
the limitations of the observed dataset, i.e. the accuracy of stellar
parameters and the selection effects that are caused by the photometric target
preselection. We find that the colour and magnitude cuts in the survey suppress
old metal-rich stars and young metal-poor stars. This suppression may be as
high as 97% in some regions of the age-metallicity relationship. The dataset
consists of 144 stars with a wide range of ages from 0.5 Gyr to 13.5 Gyr,
Galactocentric distances from 6 kpc to 9.5 kpc, and vertical distances from the
plane 0 < |Z| < 1.5 kpc. On this basis, we find that i) the observed
age-metallicity relation is nearly flat in the range of ages between 0 Gyr and
8 Gyr; ii) at ages older than 9 Gyr, we see a decrease in [Fe/H] and a clear
absence of metal-rich stars; this cannot be explained by the survey selection
functions; iii) there is a significant scatter of [Fe/H] at any age; and iv)
[Mg/Fe] increases with age, but the dispersion of [Mg/Fe] at ages > 9 Gyr is
not as small as advocated by some other studies. In agreement with earlier
work, we find that radial abundance gradients change as a function of vertical
distance from the plane. The [Mg/Fe] gradient steepens and becomes negative. In
addition, we show that the inner disk is not only more alpha-rich compared to
the outer disk, but also older, as traced independently by the ages and Mg
abundances of stars.Comment: accepted for publication in A&
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