6,457 research outputs found
Induced pluripotent stem cells, a giant leap for mankind therapeutic applications
Induced pluripotent stem cells (iPSC) technology has propelled the field of stem
cells biology, providing new cells to explore the molecular mechanisms of
pluripotency, cancer biology and aging. A major advantage of human iPSC,
compared to the pluripotent embryonic stem cells, is that they can be generated
from virtually any embryonic or adult somatic cell type without destruction of
human blastocysts. In addition, iPSC can be generated from somatic cells
harvested from normal individuals or patients, and used as a cellular tool to
unravel mechanisms of human development and to model diseases in a manner
not possible before. Besides these fundamental aspects of human biology and
physiology that are revealed using iPSC or iPSC-derived cells, these cells hold an
immense potential for cell-based therapies, and for the discovery of new or
personalized pharmacological treatments for many disorders. Here, we review
some of the current challenges and concerns about iPSC technology. We
introduce the potential held by iPSC for research and development of novel
health-related applications. We briefly present the efforts made by the scientific
and clinical communities to create the necessary guidelines and regulations to
achieve the highest quality standards in the procedures for iPSC generation,
characterization and long-term preservation. Finally, we present some of the
audacious and pioneer clinical trials in progress with iPSC-derived cells.info:eu-repo/semantics/publishedVersio
Analytical characterization of ancient mortars from the archaeological roman site of Pisões (Beja, Portugal)
The analytical characterization of mortar samples from the roman archaeological site of Pisões, located in
Southern Portugal, were carried out by means of X-ray diffractometry (XRD), thermogravimetry (TGADTA),
optical and electron scanning microscopy (SEM-EDS), potentiometry and combustion analysis.
The Pisões archaeological complex includes a villa rustica, characterized by well-preserved mosaics and
thermal baths, as well as a mill and a mausoleum. Countryside villae epitomized the Romanization of the
Iberian Peninsula for over six centuries (2nd century BCE–4th century CE). Nevertheless, most of the
Roman villae identified in Portugal have not yet been systematically explored and studied.
This study provides valuable data on the construction materials and techniques used in Roman times in
the Iberian Peninsula. The careful selection of raw materials and the use of natural and artificial pozzolanic
materials can explain the favourable state of conservation, mechanical strength and long-term
durability of these mortars
GRASS UTILIZATION IN GROWING FINISHING BĂŤSARO PIGS (85-107 KG). PERFORMANCE AND CARCASS COMPOSITION
The use of different quantities of vegetables, forages or fresh grass as fodder for growing-finishing pigs is an important factor of the northern Portugal traditional system. The increasing development of swine production in outdoor systems, extensive and organic production, turns to upcoming natural diets, in which grass performs a significant part. With regard to this, some investigation has been made concerning the use of fibre-rich feed ingredients in pig nutrition. Metabolic effects of its ingestion are analysed concerning different sights (economical, social, environmental and physiological ones).
The aim of this work was to study the effects of grass utilization in the diets on performances of finishing BĂsaro pigs. A total of 22 pigs (16 castrated males and 6 females) was housed outdoor and fed ad libitum (37 – 85 kg live weight) with a growing diet and then transferred to an indoor system (with free access to an outdoor area) for 49 days, according to 3 different treatments: 100% concentrate (C), 75% concentrate + ad libitum grass (CE75), 50% concentrate + ad libitum grass (CE50). The grass was supplied and its intake registered on a daily basis. Every 14 days, the pigs were weighted and their back fat (P2 in vivo) measured. After slaughter (average weight of 107 kg LW), yield and ½ left carcass characteristics were controlled. During the outdoor growing phase, the ADG was 513 g/day. During the indoor finishing phase, the increase grass intake was proportional to the reduction of concentrate in the diet. The ADG (g) and the fat deposition (P2 cm) were significantly different (P<0,05) in the 3 treatments (ADG: C=641, CE75=467, CE50=356 and: C=11,4, CE75=+9,5, CE50=+6,2). The empty body weight (kg) was also proportional to the intake of concentrate (C=116,2; CE75=107,7; CE50=102,2). Comparatively to the weight of the body parts, pigs that had higher intake of grass and lower of concentrate showed a higher % of shoulder (P<0,05; C=20,4, CE75=21,7, CE50=22,2) and the pH45min of CE carcasses was significantly higher (P<0,05). As a conclusion, concentrate substitution for grass showed a slower growing rate, thinner carcasses and a high technological quality.
Neverthelles variability (CV %) of the productive parameters at the end of this study were higher in the treatments that included grass: live weight (C= 10,5%; C75=10,7%; C50=14,3%), finishing ADG (C=24%; C75=37%, C50=42%), and final fat (C=37%; C75=32%, C50=52%). These values suggest that the utilization of fibrous feeds in growing-finishing swine may be one of the possible explanations of the more heterogeneous products and carcasses found in the traditional or extensive systems, common users of fibrous feeds in the carcass finishing phase
Identifying Special Structures in Interval-Data via Model-Base Clustering
In this paper we present a model-based approach to the clustering of interval data building on recently
proposed parametric models. These methods consider configurations for the variance-covariance matrix that
take the nature of the interval data directly into account. The proposed framework relies on parametrizations
considering the inherent variability of the relevant data units and the relation that may exist between
this variability and the corresponding value levels. Using both synthetic and real data sets the pertinence of
the proposed methodology is shown, as the method effectively selects heterocedastic models with restricted
covariance structures when they are the most suitable, even in situations with limited information. Moreover,
considering special configurations of the variance-covariance matrix, adapted to nature of interval data,
proves to be the adequate approach. The presented study also makes clear the need to consider both the information about position (conveyed by the MidPoints) and intrinsic variability (conveyed by the Log-Ranges)
when analysing interval data.info:eu-repo/semantics/publishedVersio
Quintessential inflation from 5D warped product spaces on a dynamical foliation
Assuming the existence of a 5D purely kinetic scalar field on the class of
warped product spaces we investigate the possibility of mimic both an
inflationary and a quintessential scenarios on 4D hypersurfaces, by
implementing a dynamical foliation on the fifth coordinate instead of a
constant one. We obtain that an induced chaotic inflationary scenario with a
geometrically induced scalar potential and an induced quasi-vacuum equation of
state on 4D dynamical hypersurfaces is possible. While on a constant foliation
the universe can be considered as matter dominated today, in a family of 4D
dynamical hypersurfaces the universe can be passing for a period of accelerated
expansion with a deceleration parameter nearly -1. This effect of the dynamical
foliation results negligible at the inflationary epoch allowing for a chaotic
scenario and becomes considerable at the present epoch allowing a
quintessential scenario.Comment: 7 pages, 1 figure Accepted for publication in Modern Physics Letters
Nutrient absorption in lambs fed diets containing different amounts of phosphorus
Objective. Evaluate the effect of increasing P intake on nutrient digestibility, and compare the true and apparent absorption coefficients of P and Ca in lambs. Materials and methods. Twenty-four Santa Ines sheep, with an average weight of 33.6 ± 1.6 kg, were distributed into four treatments (0, 2, 4 and 6 g/day of supplementary P) with forage: concentrate ratio of 70:30. The study of apparent nutrient digestibility was conducted during the first week, using the total feces collection method. During the second week, after injection of 7.4 MBq of 32P and 7.7 MBq of 45Ca, apparent (AAC) and true (TAC) absorption coefficients of P and Ca were determined. The lambs were kept in metabolic cages. Results. The increase in P intake did not affect (p>0.05) dry matter, crude protein, NDF or ADF digestibility, but the TAC of P and Ca and mineral matter digestibility decreased. The AAC was not affected (p=0.10). A cubic relationship was observed between P intake and TAC (TAC=2.16–1.95X+0.55X2-0.04X3; R2=0.38) and linear relationship with the TAC of Ca (TAC=0.559–0.03X; R2=0.26). TAC and AAC values were different (p<0.001). Conclusions. The increase in P intake doesn’t impact organic matter digestibility, but does affect P and Ca absorption. Apparent digestibility is not a reliable parameter to determine the efficiency of P and Ca absorption
A hybrid MPPT algorithm based on DE-IC for photovoltaic systems under partial shading conditions
This paper presents a hybrid maximum power point tracking (MPPT), which combines a metaheuristic algorithm and a traditional MPPT method applied in a photovoltaic system operating under partial shading conditions. The MPPTs based on traditional methods are not able to track the global maxi-mum power point (GMPP) when partial shadings occur. Thus, MPPT algorithms based on metaheuristic algorithms, which are used for global optimization, have presented efficiency to extract the maximum power from photovoltaic arrays. However, these methods are random, resulting in large power oscillations in transients of small variations in solar irradiance. Therefore, this paper proposes the metaheuristic algorithm called Differential Evolution (DE) to seek and track the GMPP. After the DE convergence, the MPPT algorithm is switched to Incremental Conductance (IC) in order to refine the tracking. The effectiveness of the algorithm is proved through simulation results. Furthermore, comparative analyses are provided for each algorithm (DE and IC) to evaluate their performances in the PV system
Electroanalytical study of fluvoxamine
Fluvoxamine (FVX) can be reduced at a mercury-
drop electrode, with a maximum peak current
intensity being obtained at a potential of -0.7 V vs. Ag/
AgCl, in an aqueous electrolyte solution of pH 2. The
compound was determined in a pharmaceutical product
and in spiked human serum by square-wave adsorptivestripping
voltammetry (SWAdSV) after accumulation at
the electrode surface, under batch conditions. Because
the presence of dissolved oxygen did not interfere significantly
with the analysis, it was also possible to
determine FVX in the pharmaceutical product by use of
a flow-injection analysis (FIA) system with SWAdSV
detection. The methods developed were validated and
successfully applied to the quantification of FVX in a
pharmaceutical product. Recoveries between 76 and
89% were obtained in serum analysis. The FIA–
SWAdSV method enabled analysis of up to 120 samples
per hour at reduced cost, implying the possibility of
competing with the chromatographic methods usually
used for this analysis
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