3,865 research outputs found
A role for the small GTPases RAC1 and RAC1b in the modulation of NIS expression: potentiation of therapy with radioactive iodine in differentiated thyroid carcinoma
Introduction or Background: The Sodium Iodide Symporter (NIS) is responsible for active transport of iodide
into thyroid follicular cells. The retention of its functional expression in most of the well-differentiated thyroid
carcinomas (DTCs) enables the use of radioactive iodine (RAI) for treatment of metastatic disease. Still, about
30% of patients with advanced forms of DTC became refractory to RAI which makes their management very
challenging. The main reason for impaired iodide uptake in refractory-DTC is the defective functional
expression of NIS. Several molecular players have been described as critical for TSH-induced NIS expression,
an example being the p38 mitogenic kinase. In breast cancer cells, the small GTPase RAC1 was shown to
mediate the positive impact of p38 kinase activity on NIS expression. We, on the other hand, have previously
shown that overexpression of RAC1b, a tumor-related splicing variant of RAC1, is associated with worse
outcomes in DTC and correlates with the MAPK-activating BRAFV600E mutation, which has been related to
the loss of NIS. Since RAC1 and RAC1b may act in an antagonistic fashion to regulate specific cellular
responses, we asked if RAC1b would be implicated in NIS downregulation observed in DTCs.
Methods Section: NIS expression levels were analyzed by RT-qPCR in a RAC1/RAC1b expression model system developed in non-transformed thyroid cell lines. A non-radioactive iodide influx assay was used to confirm the impact of RAC1-signaling on the efficacy of iodide uptake.
Results Section: We demonstrate that ectopic overexpression of RAC1b is sufficient to decrease TSH-induced NIS expression, antagonizing the positive effect of RAC1 GTPase. Moreover, we clearly document, for the first time in thyroid cells, that both NIS expression and iodide uptake are downregulated upon RAC1 inhibition, supporting the role of canonical RAC1 signaling in promoting TSH-induced NIS expression.
Conclusion: Our findings provide evidence that RAC1 and RAC1b signaling are implicated in the regulation of NIS expression in thyroid cells and suggest that RAC1b overexpression may be one of the mechanisms contributing to the low levels of NIS observed in some subgroups of DTCs, antagonizing RAC1 stimulatory effect on the TSH/cAMP-mediated induction of NIS expression.FCT - PTDC/BIAMOL/31787/2017N/
Green walls an efficient solution for hygrothermal, noise and air pollution control in the buildings
A building façade is considered to form the first line of protection against adverse climate and environmental conditions in an urban area, such as wind and rain, leading it to be affected and eventually damaged by continued and direct interaction.
Furthermore, the increasing ecological and environmental concerns, due to the global warming associated with air and noise pollution, is proved to be linked to the small quantity of vegetation and green areas in urban environments and to technological development. Depending on that, new approaches to improve the environment quality in urban areas started to be developed. One of these approaches is Vertical and Horizontal Gardens, which are taking increasing roles in the recent years.
Historically, vertical gardens were the starting point for considering the possibility of growing plants on vertical surfaces and some examples are dated back to 2000 years in Mediterranean regions. Green walls were first used in buildings for simply decorative purposes in many cities of Europe and north America in the 19th century. However, the environmental control value of the green walls in Europe was not noticed until 1980s, where a lot of programs and studies recognized their ability to mitigate particulate
matter, reduce noise and provide cooling effects leading to the development of a lot of projects that promoted the usages of green walls.
The aim of this paper is to evaluate the efficiency of green walls regarding their ability to mitigate environmental conflicts, taking in consideration the different methods of implementation and their respective advantages and disadvantages.
This study systemically reviews recent researches on nature-based solutions namely green walls. Followed by an analysis of the environmental properties of different models of solutions, and an analysis of the costs and the average payback periods. The results of the review can provide a feedback of the most efficient green solutions that could offer good environmental quality with economic advantages.
The first part of the paper provides an overall introduction considering the green walls and their implementing methodologies. While the second part presents the environmental and economic effects of the different vertical greening systems on the envelope of the building compared to common building materials. The final results prove that each system of vertical greening varies depending on the levels of environmental benefits and costs, where some systems are proved to be economically sustainable with good environmental properties while others offer a wider range of plants with several implementation methods making them easierinfo:eu-repo/semantics/publishedVersio
Geomorphological units of mainland Portugal
São representadas cartograficamente as unidades geomorfológicas identificadas para os 89015 km2 do território de Portugal Continental. A delimitação das unidades teve por base a análise dos padrões da textura fornecida por imagens SRTM, com revisão e adaptação posterior à altimetria e à geologia, para os
quais foram usadas bases cartográficas digitais. Foram considerados três níveis taxionómicos que permitem descrever e caracterizar áreas homogéneas do ponto de vista geomorfológico. As três unidades de 1º nível baseiam-se nas unidades morfostruturais clássicas consideradas para a Península Ibérica. As dez unidades de 2º nível constituem, na sua maioria, divisões clássicas do relevo de Portugal Continental, agora agrupadas de acordo com a metodologia adoptada e designadas como unidades morfosculturais. As 56 unidades de 3º nível, ou subunidades morfosculturais, foram individualizadas com base nos padrões de relevo identifi cados nas imagens SRTM e na observação de campo e adquiriram uma designação baseada essencialmente nas geoformas que as individualizam e na toponímia local. As unidades geomorfológicas identificadas são descritas através de características do relevo, dissecação fluvial, estruturas, tipo de drenagem e base geológica, bem como de parâmetros numéricos gerados de forma automática, como classes de altitude e de declividade. Pretende-se que o mapa elaborado possa contribuir para a gestão territorial, em especial na tomada de decisões em conservação da natureza.Fundação para a Ciência e a Tecnologia (FCT); CNPq (Conselho Nacional de Desenvolvimento
Científico e Tecnológico) (Brasil
Homogenization on multi-materials' elements: application to printed circuit boards and warpage analysis
Multi-material domains are often found in industrial applications. Modelling them can be computationally very expensive due to meshing requirements. The finite element properties comprising different materials are hardly accurate. In this work, a new homogenization method that simplifies the computation of the homogenized Young modulus, Poisson ratio and thermal expansion coefficient is proposed, and applied to composite-like material on a printed circuit board. The results show a good properties correspondence between the homogenized domain and the real geometry simulation.This research is sponsored:
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by the Portugal Incentive System for Research and
Technological Development. Project in co
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promotion nº
36265/2013 (Project HMIExcel
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2013
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2015),
and
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by FCT with the reference project
UID/EEA/04436/2013, by FEDER funds through the
COMPETE 2020
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Programa Operacional
Competitividade e Internacionalização (POCI) with the
reference project POCI
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01
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0145
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FEDER
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006941info:eu-repo/semantics/publishedVersio
Selecting fog harvesting meshes for environmental conditioning structures
Fog harvesting is a technique used to collect water
from the fog. This technique became widely used around the
world due to the lack of fresh water, as fog harvesting is
considered to represent an economical and a reliable source of
water. On that sense, fog collecting methods are mostly
implemented in areas that lack access to fresh water and is
mostly used for agricultural purposes and, in some cases, also
for providing clean drinking water. The basic idea of
harvesting the fog was first developed by farmers when some
types of adjoining cavities and containers were put around
plants to collect water from humid air, after that those
techniques were turned into fog harvesting structures. The
introduction of fog harvesting techniques was accompanied
with the introduction of new materials and different structures,
providing a range of options in regards to the meshes and to the
harvesting methods. In this paper, a practical and theoretical
assessment of existing fog harvesting meshes is performed in
order to characterize their economic and physical
characteristics. The final objective is to provide information
about their ability to perform in different conditions which is to
be added to an environmental conditioning structure for
exterior spaces.(undefined
New hydrogel biomaterial for the treatment of diabetic ulcers
info:eu-repo/semantics/publishedVersio
The libraries that made SUCEST
A large-scale sequencing of sugarcane expressed sequence tags (ESTs) was carried out as a first step in depicting the genome of this important tropical crop. Twenty-six unidirectional cDNA libraries were constructed from a variety of tissues sampled from thirteen different sugarcane cultivars. A total of 291,689 cDNA clones were sequenced in their 5? and 3?end regions. After trimming low-quality sequences and removing vector and ribosomal RNA sequences, 237,954 ESTs potentially derived from protein-encoding messenger RNA (mRNA) remained. The average insert size in all libraries was estimated to be 1,250bp with the insert length varying from 500 to 5,000 bp. Clustering the 237,954 sugarcane ESTs resulted in 43,141clusters, from which 38% had no matches with existing sequences in the public databases. Around 53% of the clusters were formed by ESTs expressed in at least two libraries while 47% of the clusters are formed by ESTs expressed in only one library. A global analysis of the ESTs indicated that around 33% contain cDNA clones with full-length insert.1
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