2,211 research outputs found
Origin of the Significant Impact of Ta on the Creep Resistance of FeCrNi Alloys
Heat resistant FeCrNi alloys are widely used in the petrochemical industry
because they exhibit a unique combination of creep and oxidation resistance at
temperatures exceeding 900C. Their creep properties are often optimized
by micro-additions of carbide forming elements. In the present work, the
influence of Ta micro-additions has been experimentally investigated both on
as-cast and aged microstructures to understand the origin of the significant
impact of this element on the creep resistance. Calculations with thermocal
software were also carried out to support experimental data. It is shown that a
small addition of Ta is beneficial as it increases the volume fraction of
stable MC carbides. We demonstrate also that additions of Ta may have a
dramatic effect on the thermal stability of microstructures. This is attributed
to a smaller equilibrium volume fraction of M23C6 and more pronounced
heterogeneous precipitation at MC/matrix interfaces. The influence on the creep
properties in then discussed
Holocene vegetation dynamics of the Eastern Mediterranean region: old controversies addressed by a new analysis
Aim: We reconstruct vegetation changes since 12 ky in the Eastern Mediterranean to examine four features of the regional vegetation history that are controversial: the extent of non-analogue vegetation assemblages in the transition from the Late Glacial to the early Holocene, the synchroneity of postglacial forest expansion, the geographical extent of temperate deciduous forest during the mid-Holocene and the timing and trigger for the re-establishment of drought-tolerant vegetation during the late Holocene. Location: The Eastern Mediterranean–Black Sea Caspian Corridor. Taxon: Vascular plants. Methods: We reconstruct vegetation changes for 122 fossil pollen records using a method that accounts for within-biome variability in pollen taxon abundance to determine the biome with which a sample has greatest affinity. Per-biome affinity threshold values were used to identify samples that do not belong to any modern biome. We apply time series analysis and mapping to examine space and time changes. Results: Sites with non-analogue vegetation were most common between 11.5 and 9.5 ky and mostly in the Carpathians. The transition from open vegetation to forest occurred at 10.64 ± 0.65 ky across the whole region. Temperate deciduous forest was not more extensive at 6 ky; maximum expansion occurred between 5.5 and 5 ky. Expansion of forest occurred between c. 4 and 2.8 k, followed by an abrupt decrease and a subsequent recovery. This pattern is not consistent with a systematic decline of forest towards more drought-tolerant vegetation in the late Holocene but is consistent with centennial-scale speleothem patterns linked to variations in moisture availability. Main Conclusions: We show the occurrence of non-analogue vegetation types peaked during early Holocene, forest expansion was synchronous across the region and there was an expansion of moisture-demanding temperate trees around 5.5 to 5 ky. There is no signal of a continuous late Holocene aridification, but changes in forest cover appear to reflect climatic rather than anthropogenic influences
Evaluation of biofilm formation on acrylic resin surfaces coated with silicon dioxide: an in situ study.
Biofilm on acrylic resin dental prostheses may cause gingival inflammation. This study evaluated the influence of a silicon dioxide coating layer applied onto acrylic resin on the adhesion of microorganisms. Blocks (5 x 5 x 3 mm) of acrylic resin were evaluated for surface roughness and divided into two groups: control (CG) and coated with silicon dioxide (LG group). The specimens were evaluated by scanning electron microscopy (n = 1) and by contact angle analysis (n = 3). For the in situ study, 20 volunteers wore acrylic palatal devices containing three samples from each group (n = 60) for 2 days. The biofilm formed was quantified by metabolic activity and total biomass using the crystal violet assay. The results were subjected to Bartlett's normality test and Gamma model with random effect for the response variable (α = 5%). The mean contact angle of the coated group was significantly lower than that of the uncoated group (p < 0.05). The metabolic activity of microorganisms in the biofilm on the blocks treated with coating was significantly lower than that of control blocks (p = 0.02). Regarding the amount of extracellular matrix produced by the microorganisms, there was no difference between the CG and LG group (p = 0.05). The application of a silicon dioxide coating on acrylic resin reduced the activity of the polymicrobial biofilm formed in situ. This coating may be advantageous for patients with conventional complete dentures or implants made of acrylic resin and who have motor difficulties that prevent them from cleaning their prostheses properly
Graphene oxide topical administration: Skin permeability studies
Nanostructured carriers have been widely used in pharmaceutical formulations for der-matological treatment. They offer targeted drug delivery, sustained release, improved biostability, and low toxicity, usually presenting advantages over conventional formulations. Due to its large surface area, small size and photothermal properties, graphene oxide (GO) has the potential to be used for such applications. Nanographene oxide (GOn) presented average sizes of 197.6 ± 11.8 nm, and a surface charge of -39.4 ± 1.8 mV, being stable in water for over 6 months. 55.5% of the mass of GOn dispersion (at a concentration of 1000 µg mL-1 ) permeated the skin after 6 h of exposure. GOn dispersions have been shown to absorb near-infrared radiation, reaching temperatures up to 45.7¿ C, within mild the photothermal therapy temperature range. Furthermore, GOn in amounts superior to those which could permeate the skin were shown not to affect human skin fibroblasts (HFF-1) morphology or viability, after 24 h of incubation. Due to its large size, no skin permeation was observed for graphite particles in aqueous dispersions stabilized with Pluronic P-123 (Gt–P-123). Altogether, for the first time, Gon’s potential as a topic administration agent and for delivery of photothermal therapy has been demonstrated.This work was financed by FEDER funds through the COMPETE 2020–Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by national funds (PIDDAC) through FCT/MCTES in the framework of the project POCI-01-0145-FEDER-031143, and Base Funding-UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy–LEPABE. Additional funding included FCT/MCTES in the framework of the project “Institute for Research and Innovation in Health Sciences” (UID/BIM/04293/2019). Authors would also like to thank the support of i3S Scientific Platforms and respective funding: HEMS, member of the national infrastructure PPBI–Portuguese Platform of Bioimaging: POCI-01-0145-FEDER-022122; and Biointerfaces and Nanotechnology (BN) Laboratory, Portuguese Funds through FCT, UID/BIM/04293/2019. Artur Pinto thanks the Portuguese Foundation for Science and Technology (FCT) for the financial support of his work contract through the Scientific Employment Stimulus-Individual Call–[CEECIND/03908/2017]. Soraia Pinto (SFRH/BD/144719/2019) would like to thank FCT, Portugal for financial support
Well-Being at Work: A Cross-Sectional Study on the Portuguese Nutritionists
This exploratory, nationwide cross-sectional study was performed to investigate the well-being of Portuguese nutritionists, in addition to outlining their professional and demographic profile. Descriptive analyses were carried out to determine the measures relating to centralising tendency and dispersion of the sample. We compared means and proportions through t-tests and Analysis of Variance (ANOVA). The sample size was 206 individuals, respecting a minimum of eight respondents per item to validate the instrument. We recruited Nutritionists from Portugal nationwide using the list of electronic mail provided by the Order of Nutritionists. We sent an electronic mail to all the Nutritionists registered in this Order. We also used messaging applications and social networks (Instagram, Facebook) to reach Nutritionists who were not accessing electronic mail. Most respondents are women (92.5%), young (mean age = 31.4 ± 8.07 years; 54.2% of participants aging under 30 years), single, and with no children. More than half are Catholic (73.8%) and have less than ten years of nutritionist undergraduate completion (55.4%). The only variable that influences well-being at work is the economic variable Household Monthly Income. Those who earn less than €500.00 per month perceive themselves at a lesser state of work well-being than those who earn from €2501.00 to €5000.00 per month.</jats:p
Beta 1 integrin predicts survival in breast cancer: a clinicopathological and immunohistochemical study
Abstract\ud
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Background\ud
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The main focus of several studies concerned with cancer progression and metastasis is to analyze the mechanisms that allow cancer cells to interact and quickly adapt with their environment. Integrins, a family of transmembrane glycoproteins, play a major role in invasive and metastatic processes. Integrins are involved in cell adhesion in both cell-extracellular matrix and cell-cell interactions, and particularly, β1 integrin is involved in proliferation and differentiation of cells in the development of epithelial tissues. This work aimed to investigate the putative role of β1 integrin expression on survival and metastasis in patients with breast invasive ductal carcinoma (IDC). In addition, we compared the expression of β1 integrin in patients with ductal carcinoma in situ (DCIS).\ud
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Methods\ud
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Through tissue microarray (TMA) slides containing 225 samples of IDC and 67 samples of DCIS, β1 integrin expression was related with several immunohistochemical markers and clinicopathologic features of prognostic significance.\ud
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Results\ud
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β1 integrin was overexpressed in 32.8% of IDC. In IDC, β1 integrin was related with HER-2 (p = 0.019) and VEGF (p = 0.011) expression and it had a significant relationship with metastasis and death (p = 0.001 and p = 0.05, respectively). Kaplan-Meier survival analysis showed that the overexpression of this protein is very significant (p = 0.002) in specific survival (number of months between diagnosis and death caused by the disease). There were no correlation between IDC and DCIS (p = 0.559) regarding β1 integrin expression.\ud
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Conclusions\ud
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Considering that the expression of β1 integrin in breast cancer remains controversial, specially its relation with survival of patients, our findings provide further evidence that β1 integrin can be a marker of poor prognosis in breast cancer.\ud
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Virtual slides\ud
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The virtual slide(s) for this article can be found here: \ud
http://www.diagnosticpathology.diagnomx.eu/vs/6652215267393871We thank CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil) and FAPESP (Fundação de Amparo a Pesquisa do Estado de São Paulo, Brazil) for financial support, CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil) and FACEPE (Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco, Brazil) for schollarships and financial support; and Deisy Mara da Silva for technical assistance.This research is in accordance with Declaration of Helsinki, and was aprooved by the local ethics comitee
Maintenance of Physical Activity Behavior by Individuals with Prediabetes and Diabetes during the COVID-19 Pandemic after Completing an Exercise Intervention in Brazil
This cross-sectional study evaluated the perception of individuals with prediabetes/diabetes about their living conditions during the COVID-19 pandemic to identify the facilitators, barriers, and reasons to remain physically active at home and adhere to recommended exercise. It included individuals with prediabetes/diabetes who had completed an exercise intervention, which started on-site and moved to a remote home-based regime due to the COVID-19 pandemic and were advised to keep exercising at home. The outcomes were assessed by a bespoke questionnaire that was developed by the research team, the Brazilian Portuguese adapted version of the Exercise Adherence Rating scale, and the Motives for Physical Activity Measure-Revised scale. Of 15 participants (8 female, 58 ± 11 years), most reported positive perceptions about their living conditions and few difficulties maintaining some physical activity at home. However, only 53.8% of them adhered to the recommended exercise. Time flexibility, no need for commuting, and a sense of autonomy were the main facilitators of home exercise, while a lack of adequate space was the main barrier. The descending order of median scores that were obtained in each reason for physical activity was fitness, enjoyment, competence, social, and appearance. Individuals with prediabetes/diabetes maintained some physical activity during the pandemic, mainly motivated by health concerns
Serum biomarkers associated with SARS-CoV-2 severity
Immunity with SARS-CoV-2 infection during the acute phase is not sufficiently well understood to differentiate mild from severe cases and identify prognostic markers. We evaluated the immune response profile using a total of 71 biomarkers in sera from patients with SARS-CoV-2 infection, confirmed by RT-PCR and controls. We correlated biological marker levels with negative control (C) asymptomatic (A), nonhospitalized (mild cases-M), and hospitalized (severe cases-S) groups. Among angiogenesis markers, we identified biomarkers that were more frequently elevated in severe cases when compared to the other groups (C, A, and M). Among cardiovascular diseases, there were biomarkers with differences between the groups, with D-dimer, GDF-15, and sICAM-1 higher in the S group. The levels of the biomarkers Myoglobin and P-Selectin were lower among patients in group M compared to those in groups S and A. Important differences in cytokines and chemokines according to the clinical course were identified. Severe cases presented altered levels when compared to group C. This study helps to characterize biological markers related to angiogenesis, growth factors, heart disease, and cytokine/chemokine production in individuals infected with SARS-CoV-2, offering prognostic signatures and a basis for understanding the biological factors in disease severity
Massive facial edema and airway obstruction secondary to acute postoperative sialadenitis or "anesthesia mumps": a case report
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
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