5,734 research outputs found
Cork–polymer biocomposites: mechanical, structural and thermal properties
This work addresses to the preparation of biocomposites resulting from the combination of different biodegradable aliphatic polyesters with cork (30 wt.%). The lignocellulosic biomass with closed cellular structure was compounded with poly(L-lactic acid) (PLLA), polyhydroxybutyrate-co-hydroxyvalerate (PHBV), poly-ε-caprolactone (PCL) and starch-poly-ε-caprolactone (SPCL) blend using a twin-screw extruder prior to injection moulding into tensile samples. The physico-mechanical and thermal properties of the matrices and the bio-based cork composites were investigated. This study shows that the addition of cork contributes to produce lightweight materials using PLLA and PHBV matrices and promotes an increase on the stiffness of PCL. The fracture morphology observations showed good physical corkâ matrix bonding with absence of voids or cavities between cork and the bio-based polyesters. Cork increases the crystallinity degree of the biocomposites. These findings suggest that the corkâ polymer biocomposites are a viable alternative to develop more sustainable composite materials, such as automotive interior parts and bio-based caps for wine bottles as it has been shown as proof-of-concept.The work was performed within the project of Corticeira Amorim S.G.P.S. on the development of new products based in/with cork. The authors gratefully acknowledge the financial support, through the COMPETE/QREN/EU funding program in the project with acronym NovelComp (QREN FCOMP-01-0202-FEDER-003107). The author E.M.F. acknowledges the financial support from the Portuguese Foundation for Science and Technology (FCT) and POPH/FSE for the post-doctoral grant (SFRH/BPD/96197/2013)
Phosphorylation of mineralocorticoid receptor ligand binding domain impairs receptor activation and has a dominant negative effect over non-phosphorylated receptors
Post-translational modification of steroid receptors allows
fine-tuning different properties of this family of proteins,
including stability, activation, or interaction with co-regulators.
Recently, a novel effect of phosphorylation on steroid receptor
biology was described. Phosphorylation of human mineralocor ticoid receptor (MR) on Ser-843, a residue placed on the ligand
binding domain, lowers affinity for agonists, producing inhibi tion of gene transactivation. We now show that MR inhibition
by phosphorylation occurs even at high agonist concentration,
suggesting that phosphorylation may also impair coupling
between ligand binding and receptor activation. Our results
demonstrate that agonists are able to induce partial nuclear
translocation of MR but fail to produce transactivation due at
least in part to impaired co-activator recruitment. The inhibi tory effect of phosphorylation on MR acts in a dominant-nega tive manner, effectively amplifying its functional effect on gene
transactivation.info:eu-repo/semantics/publishedVersio
Density separation of petrous bone powders for optimized ancient DNA yields
Density separation is a process routinely used to segregate minerals, organic matter, and even microplastics, from soils and sediments. Here we apply density separation to archaeological bone powders before DNA extraction to increase endoge-nous DNA recovery relative to a standard control extraction of the same powders. Using nontoxic heavy liquid solutions, we separated powders from the petrous bones of 10 individuals of similar archaeological preservation into eight density inter-vals (2.15 to 2.45 g/cm3 , in 0.05 increments). We found that the 2.30 to 2.35 g/cm 3 and 2.35 to 2.40 g/cm3 intervals yield-ed up to 5.28-fold more endogenous unique DNA than the corresponding standard extraction (and up to 8.53-fold before duplicate read removal), while maintaining signals of ancient DNA authenticity and not reducing library complexity.
Although small 0.05 g/cm 3 intervals may maximally optimize yields, a single separation to remove materials with a density above 2.40 g/cm3 yielded up to 2.57-fold more endogenous DNA on average, which enables the simultaneous separation of samples that vary in preservation or in the type of material analyzed. While requiring no new ancient DNA laboratory equipment and fewer than 30 min of extra laboratory work, the implementation of density separation before DNA extraction can substantially boost endogenous DNA yields without decreasing library complexity. Although subsequent studies are required, we present theoretical and practical foundations that may prove useful when applied to other ancient DNA substrates such as teeth, other bones, and sediments
Magnesium and aluminum sulfates in salt efflorescences from acid mine drainage in the Iberian Pyrite Belt (SW Spain)
Proceedings IMWA 2016, Freiberg/Germany | Drebenstedt, Carsten, Paul, Michael (eds.) | Mining Meets Water – Conflicts and Solutions.The current study is focused on AMD-precipitates that compose the typical magnesium and aluminum
sulfate assemblages in the Spanish sector of the Iberian Pyrite Belt (SW Spain). The main objectives
are identify and describe the composition, morphology and paragenetic relationships of these sulfate
phases.
From the methodological pint of view, sampling procedure covered the entire metallogenetic province,
including five selected representative mines and eight river basins, which are the main receptors of the
acid mine drainage discharges. The mineralogical analyses were performed by X-Ray diffraction and
electron microscopy. The obtained results showed the extraordinary abundance of aluminum sulfates
with acicular habit, from the series pickeringite-apjhonite-halotrichite. They form typical assemblages
with other aluminum sulfates, such as alunogen and tamarugite, and with the Mg sulfates: epsomite
and hexahydrite. Moreover, the paragenetic relationships indicate the late occurrence of acicular Alsulfates
from the halotrichite group.Financial support for this research was provided by the Andalusian Autonomous Government Excellence
Project, code P06-RNM-02167. This work was also co-funded by the European Union through the European
Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalização), project ICT (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER-007690 and
national funds provided by Fundação para a Ciência e Tecnologia.info:eu-repo/semantics/publishedVersio
Inverse Classification for Comparison-based Interpretability in Machine Learning
In the context of post-hoc interpretability, this paper addresses the task of
explaining the prediction of a classifier, considering the case where no
information is available, neither on the classifier itself, nor on the
processed data (neither the training nor the test data). It proposes an
instance-based approach whose principle consists in determining the minimal
changes needed to alter a prediction: given a data point whose classification
must be explained, the proposed method consists in identifying a close
neighbour classified differently, where the closeness definition integrates a
sparsity constraint. This principle is implemented using observation generation
in the Growing Spheres algorithm. Experimental results on two datasets
illustrate the relevance of the proposed approach that can be used to gain
knowledge about the classifier.Comment: preprin
Interactive use of communication by verbal and non-verbal autistic children
TEMA: comunicação de crianças autistas. OBJETIVO: avaliar a funcionalidade da comunicação de crianças incluídas no espectro autístico divididas em dois grupos (verbais e não verbais) e identificar as possíveis relações entre os grupos estudados. MÉTODO: foram sujeitos 20 crianças autistas, 10 verbais e 10 não verbais, com idade variando entre 2a e 10 m e 10a e 6m de vida. Todos os sujeitos foram gravados durante 30 minutos, em situação de interação espontânea com a mãe. O corpus das gravações dos dois grupos foi analisado quanto ao desempenho do perfil funcional de comunicação de cada sujeito, de cada grupo e as possíveis relações existentes entre os dois grupos. RESULTADOS: os dados referentes à ocupação do espaço comunicativo sugerem equilíbrio entre a comunicação da criança autista e sua mãe. Quanto ao número de atos comunicativos produzidos por minuto, nota-se que há uma visível divisão entre as crianças, que coincide com a divisão de grupos proposta: crianças autistas verbais e crianças autistas não verbais. Com relação à utilização dos meios comunicativos pelas crianças autistas observa-se que tanto as crianças autistas não verbais como as verbais fazem grande uso do meio gestual para se comunicarem. Os dados correspondentes à utilização das funções comunicativas mais inter-pessoais apontam a dificuldade da criança autista em interagir com o outro CONCLUSÃO: a caracterização do perfil funcional da comunicação realizada neste estudo confirmou a dificuldade destas crianças no estabelecimento de interações comunicativas e como essas dificuldades independem do meio comunicativo utilizado.BACKGROUND: communication of autistic children. AIM: to assess the communication functionality of verbal and non-verbal children of the autistic spectrum and to identify possible associations amongst the groups. METHOD: subjects were 20 children of the autistic spectrum divided into two groups: V with 10 verbal children and NV with 10 non-verbal children with ages varying between 2y10m and 10y6m. All subjects were video recorded during 30 minutes of spontaneous interaction with their mothers. The samples were analyzed according to the functional communicative profile and comparisons within and between groups were conducted. RESULTS: data referring to the occupation of communicative space suggest that there is an even balance between each child and his mother. The number of communicative acts per minute shows a clear difference between verbal and non-verbal children. Both verbal and non-verbal children use mostly the gestual communicative mean in their interactions. Data about the use of interpersonal communicative functions point out to the autistic children's great interactive impairment. CONCLUSION: the characterization of the functional communicative profile proposed in this study confirmed the autistic children's difficulties with interpersonal communication and that these difficulties do not depend on the preferred communicative mean
Functional aspects of communication: a longitudinal study of the first three years of life
O objetivo deste estudo de casos múltiplos é apresentar elementos para a discussão e a análise do desenvolvimento da comunicação desde o período pré-verbal. A apresentação dos casos inicia-se com a descrição do corpus de análise, seguida pela síntese dos dados referentes aos aspectos pragmáticos da comunicação de seis sujeitos, entre o primeiro e o 36º mês de vida. Foram incluídos os dados referentes ao número de atos comunicativos expressos por minuto, a ocupação do espaço comunicativo, a proporção de utilização dos meios comunicativos e a proporção de interatividade da comunicação. A análise individualizada do número de atos comunicativos produzidos em cada uma das amostras evidencia uma tendência crescente quase constante. No entanto, variações individuais também ocorreram. A ocupação do espaço comunicativo mostrou variações maiores e mais constantes que, não obstante, continuam a evidenciar evolução. O acompanhamento longitudinal possibilita a observação da proporção do uso do meio verbal e seu papel fundamental na comunicação de crianças a partir dos 21 meses. A partir dos 30 meses, esse meio é mais usado que o meio gestual, embora os gestos continuem a ser responsáveis por uma parte importante da comunicação iniciada pela criança. No que diz respeito à interatividade de comunicação, os dados evidenciam que os bebês buscam interação desde o nascimento e que, com o avanço da idade, ampliam suas habilidades comunicativas em qualidade e quantidade.The aim of this multiple case-study is to present issues to the analysis and discussion of communicative development since the pre-verbal period. The case presentation starts with the description of the analyzed sample followed by the synthesis of data regarding the pragmatic aspects of six subjects, from the 1st to the 36th month of life. Data regarding the number of communicative acts expressed per minute, occupation of the communicative space, proportion of use of the communicative means and the communication's interaction proportion are included. The individualized analysis of the number of communicative acts produced per minute in each sample shows an increasing tendency that is almost constant, but also frequent individual variations. The occupation of the communicative space has shown larger and more constant variations that, nevertheless, continue to evidence evolution. The longitudinal follow-up allowed the observation of the proportion of the use of the verbal communicative mean and its essential role in the child's communication from the 21st month on. Since the 30th month the verbal mean is the more frequent but the gestural mean is still responsible for an important part of the communication initiated by the child. In what refer to the communication's interactivity, data show that the infant seek the interactivity since birth and that with age improve the quality and quantity of his/her communication's abilities
Salt efflorescences in the iberian pyrite belt: occurrence and distribution
The evolution of sulfide wastes promotes acid mine drainage and
phenomena of supergenic neoformation. These contribute to a
secondary paragenesis, often dominated by salt efflorescences.
These can be used as mineralogical indicators of reactivity
conditions and of AMD potential. The present study shows the
salt efflorescences that develop in the Spanish sector of the
Iberian Pyrite Belt, as a result of the strong acid mine drainage
observed in this region. The obtained results showed dominance
of metallic sulfates. Depending on the proximity to the sulfide
sources, there are different types of assemblages. Iron and
cooper minerals dominate inside the mining areas, whereas
magnesium sulfates occur more abundantly in the receiving river
networkFinancial support was provided by the Andalusian Autonomous
Government Excellence Project, code P06-RNM-02167. This work
was also co-funded by the European Union through the European
Regional Development Fund, based on COMPETE 2020 (Programa
Operacional da Competitividade e Internacionalização), project
ICT (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER-
007690 and national funds provided by Fundação para a Ciência
e Tecnologia.info:eu-repo/semantics/publishedVersio
Fire spalling sensitivity of concrete made with recycled concrete aggregates (RCA)
The fire spalling of concrete is a complex phenomenon, which can affect the integrity of the structures during a fire. This thermal instability is associated with a complex coupled chemo-thermo-hydro-mechanical mechanism and it can be influenced by many factors, related to material (e.g. per- meability, porosity and water content), geometry (e.g. shape and size) and environmental parameters (e.g. mechanical load and heating rate). Concrete made with recycled concrete aggregates presents higher porosity, higher water content and different interfaces between aggregates and mortar. All these aspects can lead to a different behaviour under fire exposure, including the spalling risk of these sustainable concretes. The main objective of this paper is to analyse the influence of the use of recycled concrete aggregates on the spalling risk of concrete. In this paper, concrete prisms with different replacement rates of recycled coarse aggregates (0 up to 100%) were exposed to a standard fire curve (ISO 834-1) with a constant uniaxial compression load. After heating, samples surfaces were evaluated by means of digital photogrammetry. Results showed that concrete with RCA is sensitive to explosive spalling. All replacement rates presented higher degree of spalling than concrete made with natural aggregates
Role of sex hormones in the innate immunity against prostate cancer cells
Squamous cell carcinoma (SCC) is a malignant, poorly differentiated neuroendocrine neoplasm. SCC is the common form of bladder cancer in rural Africa where S. haematobium is prevalent. In contrast, the majority of bladder cancer in developing countries and regions not endemic for urogenital schistosomiasis is transitional cell carcinoma (TCC) that arises from the transitional epithelium lining of the bladder. The parasite eggs trapped in the bladder wall release antigens and other metabolites (presumably evolved to expedite egress to the urine, and hence to the external environment). However, the phenomenon leads to haematuria and to chronic inflammation, in turn increasing risk of SCC of the bladder. In addition to the hormone- -like effects of the parasite estradiol-related molecules on the endocrine and immune system of the host, in relation to cancer initiation metabolites of estrogens can be also considered as carcinogenic chemicals.info:eu-repo/semantics/publishedVersio
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