Dispersion and re-agglomeration of graphite nanoplates in polypropylene melts under controlled flow conditions

The kinetics of GnP dispersion in polypropylene melt was studied using a prototype small scale modular extensional mixer. Its modular nature enabled the sequential application of a mixing step, melt relaxation, and a second mixing step. The latter could reproduce the flow conditions on the first mixing step, or generate milder flow conditions. The effect of these sequences of flow constraints upon GnP dispersion along the mixer length was studied for composites with 2 and 10 wt.% GnP. The samples collected along the first mixing zone showed a gradual decrease of number and size of GnP agglomerates, at a rate that was independent of the flow conditions imposed to the melt, but dependent on composition. The relaxation zone induced GnP re-agglomeration, and the application of a second mixing step caused variable dispersion results that were largely dependent on the hydrodynamic stresses generated.Project Matepro – Optimizing Materials and Processes (NORTE-07-0124-FEDER-000037) by Programam Operacional Regional do Norte (ON.2

Higher trait mindfulness is associated with empathy but not with emotion recognition abilities

Mindfulness involves an intentional and non-judgemental attention or awareness of present-moment experiences. It can be cultivated by meditation practice or present as an inherent disposition or trait. Higher trait mindfulness has been associated with improved emotional skills, but evidence comes primarily from studies on emotion regulation. It remains unclear whether improvements extend to other aspects of emotional processing, namely the ability to recognize emotions in others. In the current study, 107 participants (Mage = 25.48 years) completed a measure of trait mindfulness, the Five Facet Mindfulness Questionnaire, and two emotion recognition tasks. These tasks required participants to categorize emotions in facial expressions and in speech prosody (modulations of the tone of voice). They also completed an empathy questionnaire and attention tasks. We found that higher trait mindfulness was associated positively with cognitive empathy, but not with the ability to recognize emotions. In fact, Bayesian analyses provided substantial evidence for the null hypothesis, both for emotion recognition in faces and in speech. Moreover, no associations were observed between mindfulness and attention performance. These findings suggest that the positive effects of trait mindfulness on emotional processing do not extend to emotion recognition abilities.info:eu-repo/semantics/publishedVersio

Prenatal Diagnosis and Management of a Fetal Goiter Hypothyroidism due to Dyshormonogenesis

Fetal goiter is a rare disorder not expected to be found during a healthy woman's pregnancy. It can be a prenatal manifestation of congenital hypothyroidism due to thyroid dyshormonogenesis and it can lead to serious perinatal complications. A vascularized fetal neck mass was detected at 29 weeks' gestation of a healthy primigravida. Magnetic resonance was suggestive of goiter causing airway deviation without polyhydramnios. Maternal thyroid function was normal and thyroid antibodies were negative. Two intra-amniotic levothyroxine infusions were performed at 32 and 33 weeks. Serial imaging control showed no progression of the mass. Elective caesarean section was performed at 38 weeks. The male newborn was admitted to the intensive care unit due to cardiorespiratory insufficiency with pulmonary hypertension. Hormonal assays revealed primary congenital hypothyroidism and ultrasonography confirmed diffuse goiter. Levothyroxine was started. Currently, he is 6 years old with adequate growth and normal psychomotor development. Genetic study found a heterozygous mutation in the TPO gene.info:eu-repo/semantics/publishedVersio

Evaluation of diabetic foot amputation rate

Acta Med Port. 2003 Nov-Dec;16(6):373-80. Epub 2003 Dec 1. [Evaluation of diabetic foot amputation rate]. [Article in Portuguese] Horta C, Vilaverde J, Mendes P, Gonçalves I, Serra L, Pinto PS, Almeida R, Carvalho R, Dores J, Serra MB. Serviços de Endocrinologia, Ortopedia e Cirurgia Vascular, Hospital Geral de Santo António, Porto. Abstract In 1987, it was created the first portuguese Diabetic Foot Clinic in Oporto, at the Hospital Geral de Santo António. The distinction between neuropathic and ischaemic foot was the key stone to reduce drastically the rate of major amputations in the first two years of activity. Since then and until 1995 the rate of major amputations had stabilised around 8%. The aim of the present study was to evaluate if there was any change in the last three years. A retrospective study was performed reviewing the clinical files of 843 new patients between 1998 and 2000. The 593 patients who presented with a foot ulcer with or without infection were selected: 60.4% with neuropathic foot and 39.6% with ischaemic one. Overall, 31 of the 593 patients with ulcer or infection were treated with major amputation (5.2%). There was a statistical difference between the major amputation outcome among the two types of foot (p < 0.001). Necrosis showed to carry a poor prognosis (30.7% in ischaemic foot vs 8,3% in neuropathic, p = 0.024). There was no further statistical significance for age, sex, type or duration of diabetes as risk factors for major amputation. This retrospective study has showed a slight reduction in the rate of major amputations since 1995. Poor prognosis was related to necrosis and ischaemic foot. Further improvement requires harder investment in patients' education, as well as in alerting the primary health care physicians, for the most unpredictable catastrophic complication of diabetes. PMID: 15631847 [PubMed - indexed for MEDLINE

Probing dispersion and re-agglomeration phenomena upon melt-mixing of polymer-functionalized graphite nanoplates

A one-step melt-mixing method is proposed to study dispersion and re-agglomeration phenomena of the as-received and functionalized graphite nanoplates in polypropylene melts. Graphite nanoplates were chemically modified via 1,3-dipolar cycloaddition of an azomethine ylide and then grafted with polypropylene-graft-maleic anhydride. The effect of surface functionalization on the dispersion kinetics, nanoparticle re-agglomeration and interface bonding with the polymer is investigated. Nanocomposites with 2 or 10 wt% of as-received and functionalized graphite nanoplates were prepared in a small-scale prototype mixer coupled to a capillary rheometer. Samples were collected along the flow axis and characterized by optical microscopy, scanning electron microscopy and electrical conductivity measurements. The as-received graphite nanoplates tend to re-agglomerate upon stress relaxation of the polymer melt. The covalent attachment of a polymer to the nanoparticle surface enhances the stability of dispersion, delaying the re-agglomeration. Surface modification also improves interfacial interactions and the resulting composites presented improved electrical conductivity.The authors acknowledge the financial support to Project Matepro Optimizing Materials and Processes, with reference NORTE-07-0124-FEDER-000037 by the Programa Operacional Regional do Norte (ON.2) and Portuguese Foundation for the Science and Technology (FCT) for PEst-C/CTM/LA0025/2013. EC acknowledges FCT for a PhD grant SFRH/BD/87214/2012

Mid-to-Late Holocene environmental reconstruction on Pico Island (Azores, Portugal) based on multiproxy analysis of Lake Caveiro sediments

The Azores constitutes the most remote archipelago of the North Atlantic Ocean. Both human colonization and natural changes have significantly modified its ecosystems. To assess the impacts of natural and anthropogenic changes over the last 8200 yr, elemental geochemistry on bulk organic matter, diatoms, Cladocera and chironomid remains were analyzed in a 952-cm long sediment (3.7m depth) from Lake Caveiro. From 8200 to 650 cal yr BP, climatic and volcanic forcing seem to have been the main drivers of biological change. Between 8200 and 6000 cal yr BP, the sedimentary sequence was characterized by dominance of volcaniclastic deposits and high abundance of aerophilic diatoms and sparse Cladocera and chironomid remains. This interval has been interpreted as indicative of unstable conditions because of intermittent renewal of lake bottom substratum owing to repetitive tephra sedimentation. Between 6000 and 3500 cal yr BP, fossil assemblages were dominated by benthic species, with an increasing trend of the planktonic/benthic (P:B) ratio, suggesting stable substratum and rising lake levels. An increase in planktonic taxa and the presence of deep-water chironomid species was found between 3500 and 1300 cal yr BP, suggesting a highstand phase. Between 1300 and 650 cal yr BP, a decreasing trend of the P:B ratio was recorded, implying a further lake shallowing. Moreover, the appearance of flowing water species suggests a period characterized by climate instability. From 650 cal yr BP to the present, a significant increase in primary production and a decline in species richness likely reflect anthropogenic impacts, such as forest clearance and the introduction of exotic species. These results highlight the impact that human, volcanic and climatic drivers have had on the environmental evolution of the ecosystems of Pico Island.This research is funded by Spanish projects PaleoNAO (CGL2010-15767), RapidNAO (CGL2013-40608-R) and PaleoModes (CGL2016-75281-C2).Peer Reviewe

Recursos e património geológico e mineiro

O território de Ponte de Lima é nesta acepção diversificado, litologicamente e estruturalmente, e comporta recursos minerais que são objecto de interesse e alvo de programas de prospecção, pesquisa e mesmo exploração mineira - actualmente mais incidente sobre os minerais não metálicos e rochas industriais. Vários ciclos de actividade extractiva passada dedicados ao ouro, estanho, volfrâmio e outros metais, desde tempos pré-Romanos até à actualidade, materializam-se em vestígios imóveis localizados ao longo da Ribeira Lima e nas encostas das serranias. Representam um património arqueológico industrial (mineiro) peculiar que em conjunto com algumas manifestações exuberantes ou raras da diversidade geológica constituem o rico património geológico do concelho, também sugerido em curiosas tradições locais, induzidas por séculos de aproveitamento latente dos recursos minerais. Formações intrusivas ácidas, rochas metamórficas e metavulcânicas, terrenos sedimentares detríticos recentes e os recursos associados são o objecto do capítulo a seguir dedicado aos recursos e património geológico e mineiro, o qual procura definir e estabelecer a importância de alguns locais de interesse geológico patrimonial. Na sequência da explanação da diversidade litológica regional, salienta-se a extraordinária diversidade mineralógica do Concelho – há minerais que no contexto Português só aqui são conhecidos

The ecological impacts of the climate changes and human colonization on cladocera and chironomid assemblages in oceanic islands – the Holocene Caveiro Lake record (Azores archipelago)

The Azores constitutes the most remote archipelago of the North Atlantic Ocean. Both human colonization and natural changes (mainly climate and active volcanism) have significantly modified its ecosystems. Cladocera and chironomid assemblages in a 805-cm long sediment core from center and deeper (4 m depth) part of Caveiro Lake in Pico Island was studied to assess the impact of environmental and climate changes over the last 5700 yr. Concordant patterns in composition between two biological groups were found, indicating major past environmental changes such as climate fluctuations (arid vs humid periods), volcanic activity, and anthropogenic intervention. Between 5200 and 5700 cal yr BP, and after a major volcanic eruption, both assemblages were dominated by littoral aquatic macrophyte species indicators, such as Alona intermedia (type) and the Psectrocladius sordinellus group. The ratio of littoral/planktonic (L:P) assemblages was low, indicating shallow lake conditions. Between 2100 and 5200 cal yr BP, an increase of planktonic and profundal chironomid taxa, suggesting lake deeper conditions. This period was also characterized by great volcanic activity on the Caveiro Lake, resulting in increased production of cladoceran resting eggs. Between 1800 and 2100 cal yr BP, coinciding with peat formation in the lake margin, an arid period was identified, reflected by the low abundance of subfossil remains of both assemblages, and the presence of high plant macro rests in the sedimentary sequence. Between 500 and 1800 cal yr BP, large changes in the L:P ratio were recorded, including the appearance of stream indicators taxa, such as Simulium sp., Zavrelimyia sp. and Rheocriotopus fuscipes type all suggesting a period characterized by climate instability. After 500 cal yr BP to nowadays the drastic reduction of total abundance and taxon diversity on both assemblages, which coincides with the establishment of the Portuguese colonizers, reflects forest clearance in lake catchment and the introduction of exotic species (plants, mammals and fishes). These results highlight the interplay that human and climate forces had on the environmental evolution of the islands’ ecosystems.Peer Reviewe