713 research outputs found
Synthesis of sub-5 nm Co-doped SnO nanoparticles and their structural, microstructural, optical and photocatalytic properties
A swift chemical route to synthesize Co-doped SnO nanopowders is
described. Pure and highly stable SnCoO (0 x
0.15) crystalline nanoparticles were synthesized, with mean grain sizes <
5 nm and the dopant element homogeneously distributed in substitutional sites
of the SnO matrix. The UV-visible diffuse reflectance spectra of the
SnCoO samples reveal red shifts, the optical bandgap
energies decreasing with increasing Co concentration. The Urbach energies of
the samples were calculated and correlated with their bandgap energies. The
photocatalytic activity of the SnCoO samples was
investigated for the 4-hydroxylbenzoic acid (4-HBA) degradation process. A
complete photodegradation of a 10 ppm 4-HBA solution was achieved using 0.02%
(w/w) of SnCoO nanoparticles in 60 min of
irradiation.Comment: 29 pages, 2 tables, 10 figure
Business model of non-governamental organizations for the development of the education sector in Mozambique: A construtivist approach
This research aims to determine the business model of non-governmental development
organizations (NGDOs) of the education sector in Mozambique. The work adopts a
constructivist methodological approach in two stages: (i) inductive, centered on the
construction of a proposal of social business model Canvas from the observation of 15
NGDOs operating in the education sector in the country, based on a theoretical framework
solidly supported in the literature; (ii) deductive, testing the proposed model using a panel
technique that allowed the refinement and reconstruction of the proposal initially
formulated. The paper contributes to the literature on social business models by making a
pioneering validation of knowledge built in this area and in a field of application not yet
explored. The contribution to international relations lies at the level of the data collected and
information produced on international cooperation in Mozambique.info:eu-repo/semantics/publishedVersio
Large area image sensing structures based on a-SiC : H: a dynamic characterization
In recent works large area hydrogenated amorphous silicon p-i-n structures with low conductivity doped layers were proposed as single element image sensors. The working principle of this type of sensor is based on the modulation, by the local illumination conditions, of the photocurrent generated by a light beam scanning the active area of the device. In order to evaluate the sensor capabilities is necessary to perform a response time characterization. This work focuses on the transient response of such sensor and on the influence of the carbon contents of the doped layers. In order to evaluate the response time a set of devices with different percentage of carbon incorporation in the doped layers is analyzed by measuring the scanner-induced photocurrent under different bias conditions
Combination of stable isotope analysis and chemometrics to discriminate geoclimatically and temporally the virgin olive oils from three mediterranean countries
The knowledge of the isotopic composition of virgin olive oil (VOO) allows the evaluation of authenticity and geographical origin, being an important tool against fraud. This study aimed to assess if VOOs produced in three Mediterranean regions could be discriminated on the basis of multivariate statistical analysis of geoclimatic and isotopic data. A total of 138 geo-referenced VOO samples from Portugal, France and Turkey from two different cultivation years were collected. The isotopic composition (δ13C, δ2H and δ18O) of VOOs was obtained using an elemental analyzer coupled to an isotope ratio mass spectrometer (EA-IRMS). One-way analysis of variance for δ13C, δ2H and δ18O showed some significant differences either between crop years or geoclimatic conditions. Based on multiple regression analyses using meteorological and geographical parameters, a meteoric water line for olive oil from Portugal, France and Turkey, in two harvest years, were created to assess the impact of climate change on their δ2H and δ18O values. Principal component analysis and Linear Discriminant Analysis, used to sort samples according to geoclimatic origin, performed best for French and Portuguese olive oils. In light of the results, multivariate isotopic analysis of VOO samples may discriminate not only between geoclimatic regions but also among cultivation years
A comparison between pure active pharmaceutical ingredients and therapeutic deep eutectic solvents: solubility and permeability studies
THEDES, so called therapeutic deep eutectic solvents are here defined as a mixture of two components,
which at a particular molar composition become liquid at room temperature and in which one of them
is an active pharmaceutical ingredient (API). In this work, THEDES based on menthol complexed with
three different APIs, ibuprofen (ibu), BA (BA) and phenylacetic acid (PA), were prepared. The interactions
between the components that constitute the THEDES were studied by NMR, confirming that the eutectic
system is formed by H-bonds between menthol and the API. The mobility of the THEDES components was
studied by PFGSE NMR spectroscopy. It was determined that the self-diffusion of the species followed the
same behavior as observed previously for ionic liquids, in which the components migrate via jumping
between voids in the suprastructure created by punctual thermal fluctuations. The solubility and permeability
of the systems in an isotonic solution was evaluated and a comparison with the pure APIs was
established through diffusion and permeability studies carried out in a Franz cell. The solubility of the
APIs when in the THEDES system can be improved up to 12 fold, namely for the system containing
ibu. Furthermore, for this system the permeability was calculated to be 14 105 cm/s representing a
3 fold increase in comparison with the pure API. With the exception of the systems containing PA an
increase in the solubility, coupled with an increase in permeability was observed. In this work, we hence
demonstrate the efficiency of THEDES as a new formulation for the enhancement of the bioavailability of
APIs by changing the physical state of the molecules from a solid dosage to a liquid system.he European Union’s Seventh Framework Programme (FP7/2007-
2013) under grant agreement nREGPOT-CT2012-316331-
POLARIS and from Project ‘‘Novel smart and biomimetic materials
for innovative regenerative medicine approaches (Ref.: RL1 - ABMR
- NORTE-01-0124-FEDER-000016)” co-financed by North Portugal
Regional Operational Programme (ON.2 – O Novo Norte), under
the National Strategic Reference Framework (NSRF), through the
European Regional Development Fund (ERDF). Funding was also
provided by Fundação para a Ciência e a Tecnologia, through contracts
LAQV-REQUIMTE: UID/QUI/50006/2013 and UCIBIOREQUIMTE:
UID/Multi/04378/2013. This work was co-financed
by the ERDF under the PT2020 Partnership Agreement (POCI-01-
0145-FEDER-007728).info:eu-repo/semantics/publishedVersio
Sperm handling in aquatic animals for artificial reproduction
Artificial reproduction involves collection and handling of gametes in a way that secures their quality and maximizes the fertilization outcome. In addition to initial sperm quality, numerous steps can affect the final result of fertilization, from the sperm collection process until gamete mixing (or co-incubation) when the spermatozoon enters or fuses with the oocyte. In this review, we summarize the whole process of sperm handling, from collection until fertilization for fish, penaeid shrimp, bivalve mollusks and marine mammals. To obtain sperm from captive animals, techniques vary widely across taxa, and include stripping by abdominal massage or testis surgical removal in fish, spermatophore collection in penaeid shrimps, gonadal scarification or temperature shock in bivalve mollusks, and voluntary collection via positive reinforcement in mammals. In most cases, special care is needed to avoid contamination by mucus, seawater, urine, or feces that can either activate sperm motility and/or decrease its quality. We also review techniques and extender solutions used for refrigerated storage of sperm across the aforementioned taxa. Finally, we give an overview of the different protocols for in vivo and in vitro fertilization including activation of sperm motility and methods for gamete co-incubation. The present study provides valuable information regarding breeder management either for animal production or species conservation.Agência financiadora
CRB-anim
ANR-11-INBS-003
Reproseed (FP7-KBBE-2009-3)
MICIU (Juan de la Cierva-Incorporacion)
IJCI-2017-34200
project ReproFl - MAR2020 Program
16-02-01-FMP-59
Fundacao para a Ciencia e Tecnologia (FCT, Portugal) through project FCT
UID/Multi/04326/2019info:eu-repo/semantics/publishedVersio
Doença de Behçet e Aneurismas Intracraneanos: Revisão da literatura “a propósito de dois casos”
Benefícios dos Ativadores Seletivos dos Recetores de Vitamina D em Doentes Transplantados Renais
Severe chronic kidney disease may lead to disturbances, such as hyperphosphatemia, increased secretion
of fibroblast growth factor -23 (FGF -23) and vitamin D deficiency. These may increase plasmatic levels of
parathyroid hormone, and decrease plasmatic levels of calcium. Altogether, these may contribute to the
development of secondary hyperparathyroidism, and to abnormalities in mineral metabolism. Kidney transplantation is the best option to improve longevity and quality of life in end -stage chronic kidney disease
patients. Vitamin D deficiency has been associated with cardiovascular disease, which is the leading cause
of death in chronic kidney disease. Therefore, diagnosing this deficiency may be pivotal for minimizing
mortality in chronic kidney disease, because pharmacological treatments for this deficiency may be prescribed.
Calcitriol is indicated for the treatment of vitamin D deficiency, both in chronic kidney disease and
in kidney transplanted patients. However, calcitriol may increase the plasmatic levels of calcium and phosphorous, which can lead to vascular calcifications, that have been associated with cardiovascular mortality.
Selective vitamin D receptor activators are indicated for the treatment of vitamin D deficiency in chronic
kidney disease. These have the advantage of being associated with lower increases of plasmatic levels of
calcium and phosphorous. These drugs also seem to have additional effects that may minimise patient
morbidity and mortality, especially due to potentially reducing cardiovascular events. Unfortunately, there
are few studies about the use of these drugs in kidney transplanted patients. Here we present a review about the physiology of vitamin D, the consequences of its deficiency in chronic kidney disease and in
kidney transplanted patients, and about the diagnosis and treatment of this deficiency. Finally, we discuss
the new line of research about the efficacy and safety of selective vitamin D receptor activators in kidney
transplanted patients
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