This work presents potential applications of low-cost fused deposition modeling 3D-printers to fabricate multiuse 3D-printed electrochemical cells for flow or batch measurements as well as the ...3D-printing of electrochemical sensing platforms. Electrochemical cells and sensors were printed with acrylonitrile butadiene styrene (ABS) and conductive graphene-doped polylactic acid (G-PLA) filaments, respectively. The overall printing operation time and estimated cost per cell were 6 h and $ 6.00, respectively, while the sensors were printed within minutes (16 sensor strips of 1 × 2 cm in 10 min at a cost of $ 1.00 each sensor). The cell performance is demonstrated for the amperometric detection of tert-butylhydroquinone, dipyrone, dopamine and diclofenac by flow-injection analysis (FIA) and batch-injection analysis (BIA) using different working electrodes, including the proposed 3D-printed sensor, which presented comparable electroanalytical performance with other carbon-based electrodes (LOD of 0.1 μmol L−1 for dopamine). Raman spectroscopy and scanning electron microscopy of the 3D-printed sensor indicated the presence of graphene nanoribbons within the polymeric matrix. Electrochemical impedance spectroscopy and heterogeneous electron transfer constants (k0) for the redox probe Ru(NH3)6+3 revealed that a glassy-carbon electrode presented faster electron transfer rates than the 3D-printed sensor; however, the latter presented lower LOD values for dopamine and catechol probably due to oxygenated functional groups at the G-PLA surface.
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•Low-cost fused deposition modeling (FDM) 3D-printers to produce cells and electrodes.•Multiuse cells for flow- (FIA) and batch-injection analysis (BIA) as well for batch condition.•Designs and printing conditions accessible for any FDM 3D-printers.•Graphene-doped PLA printed sensors for voltammetric and amperometric detection.•Electroanalytical performance similar to GCE modified with carbon nanomaterials.
In the fog computing paradigm, fog nodes are placed on the network edge to meet end-user demands with low latency, providing the possibility of new applications. Although the role of the cloud ...remains unchanged, a new network infrastructure for fog nodes must be created. The design of such an infrastructure must consider user mobility, which causes variations in workload demand over time in different regions. Properly deciding on the location of fog nodes is important to reduce the costs associated with their deployment and maintenance. To meet these demands, this paper discusses the problem of locating fog nodes and proposes a solution which considers time-varying demands, with two classes of workload in terms of latency. The solution was modeled as a mixed-integer linear programming formulation with multiple criteria. An evaluation with real data showed that an improvement in end-user service can be obtained in conjunction with the minimization of the costs by deploying fewer servers in the infrastructure. Furthermore, results show that costs can be further reduced if a limited blocking of requests is tolerated.
Hydropower is the backbone of the Brazilian electricity generation sector. Even though the use of this resource is advantaged in terms of greenhouse gas emissions, last years׳ severe droughts have ...exposed the country׳s huge dependency on hydroelectricity. Brazil׳s electricity supply system has shown to be vulnerable to electricity shortages and has demanded significant overhaul in order to address its challenges. The present paper provides a comprehensive review of the current status of the Brazilian electricity sector and discusses diversification of electricity generation mix as a strategy to improve electricity supply security in the country. An overview of the main features of the energy sources applied in Brazil is also presented through a review of the latest available generation data. The central section of this work is a discussion of the main causes of the current crisis and the future role of renewable energy sources in a 10-year perspective.
The aim of this study was to analyze levels of fatigue and resilience of Brazilian graduate students during the COVID-19 pandemic and to determine whether there is an association between fatigue and ...resilience and sociodemographic and academic factors. Data were analyzed using descriptive and inferential statistics, and it was discovered that the variables associated with higher levels of resilience were age; having children; being retired; receiving income above five minimum wages; having had greater problems in other phases of the research schedule; coming from private universities; being from the north of Brazil; studying the area of Health; and having their research schedule unaffected during the pandemic. On the other hand, lack of resilience was associated with not having children; being less well-off financially; being younger; being a woman; studying in a public university; and having to postpone part of the research during the pandemic. The conclusion of the study indicated the need for graduate programs to design strategies to deal with fatigue and promote resilience in Master's and PhD students.
Aims Struvite (MgNH₄PO₄.6H₂O) recovered from wastewater can be used as fertilizer. The agronomic effectiveness of struvite has mostly been evaluated using ground fertilizer mixed through soil. ...However, fertilizers are most commonly applied in granular form in the field. In this study, we assessed the dissolution and effectiveness of different struvites when applied in granular or powdered form. Methods Phosphorus (P) diffusion in soil, determined using a visualization technique and chemical analyses, and P uptake by 6-week old wheat was compared for soluble fertilizer (monoammonium phosphate, MAP), a commercial struvite and three synthesized struvites with different excess MgO, in both granular and ground form. Results Ground struvite mixed through soil quickly dissolved and its agronomic effectiveness was similar to that of MAP. For pure granular struvite, the granule dissolution rate ranged from circa 0.03 mg d⁻¹ in alkaline soil to 0.43 mg d⁻¹ in acidic soil. Excess base in the struvite fertilizer reduced its dissolution rate. The P uptake by wheat followed the order MAP >> struvite ≥ control (no P), with no significant difference between the control and the struvite treatment in alkaline soil. Conclusions Both fertilizer characteristics (particle size, excess base) and soil pH strongly affect the dissolution rate of struvite and hence its agronomic effectiveness.
During the morphological changes occurring in osteoblast differentiation, Sonic hedgehog (Shh) plays a crucial role. While some progress has been made in understanding this process, the epigenetic ...mechanisms governing the expression of Hh signaling members in response to bone morphogenetic protein 7 (BMP7) signaling in osteoblasts remain poorly understood. To delve deeper into this issue, we treated pre‐osteoblasts (pObs) with 100 ng/mL of BMP7 for up to 21 days. Initially, we validated the osteogenic phenotype by confirming elevated expression of well‐defined gene biomarkers, including Runx2, Osterix, Alkaline Phosphatase (Alp), and bone sialoprotein (Bsp). Simultaneously, Hh signaling‐related members Sonic (Shh), Indian (Ihh), and Desert (Dhh) Hedgehog (Hh) exhibited nuanced modulation over the 21 days in vitro period. Subsequently, we evaluated epigenetic markers, and our data revealed a notable change in the CpG methylation profile, considering the methylation/hydroxymethylation ratio. CpG methylation is a reversible process regulated by DNA methyltransferases and demethylases, including Ten‐eleven translocation (Tets), which also exhibited changes during the acquisition of the osteogenic phenotype. Specifically, we measured the methylation pattern of Shh‐related genes and demonstrated a positive Pearson correlation for GLI Family Zinc Finger 1 (Gli1) and Patched (Ptch1). This data underscores the significance of the epigenetic machinery in modulating the BMP7‐induced osteogenic phenotype by influencing the activity of Shh‐related genes. In conclusion, this study highlights the positive impact of epigenetic control on the expression of genes related to hedgehog signaling during the morphogenetic changes induced by BMP7 signaling in osteoblasts.
As more patients are surviving intensive care, mental health concerns in survivors have become a research priority. Among these, post-traumatic stress disorder (PTSD) can have an important impact on ...the quality of life of critical care survivors. However, data on its burden are conflicting. Therefore, this systematic review and meta-analysis aimed to evaluate the prevalence of PTSD symptoms in adult critical care patients after intensive care unit (ICU) discharge.
We searched MEDLINE, EMBASE, LILACS, Web of Science, PsycNET, and Scopus databases from inception to September 2018. We included observational studies assessing the prevalence of PTSD symptoms in adult critical care survivors. Two reviewers independently screened studies and extracted data. Studies were meta-analyzed using a random-effects model to estimate PTSD symptom prevalence at different time points, also estimating confidence and prediction intervals. Subgroup and meta-regression analyses were performed to explore heterogeneity. Risk of bias was assessed using the Joanna Briggs Institute tool and the GRADE approach.
Of 13,267 studies retrieved, 48 were included in this review. Overall prevalence of PTSD symptoms was 19.83% (95% confidence interval CI, 16.72-23.13; I
= 90%, low quality of evidence). Prevalence varied widely across studies, with a wide range of expected prevalence (from 3.70 to 43.73% in 95% of settings). Point prevalence estimates were 15.93% (95% CI, 11.15-21.35; I
= 90%; 17 studies), 16.80% (95% CI, 13.74-20.09; I
= 66%; 13 studies), 18.96% (95% CI, 14.28-24.12; I
= 92%; 13 studies), and 20.21% (95% CI, 13.79-27.44; I
= 58%; 7 studies) at 3, 6, 12, and > 12 months after discharge, respectively.
PTSD symptoms may affect 1 in every 5 adult critical care survivors, with a high expected prevalence 12 months after discharge. ICU survivors should be screened for PTSD symptoms and cared for accordingly, given the potential negative impact of PTSD on quality of life. In addition, action should be taken to further explore the causal relationship between ICU stay and PTSD, as well as to propose early measures to prevent PTSD in this population.
PROSPERO, CRD42017075124 , Registered 6 December 2017.
X-ray structural determinations and computational studies were used to investigate halogen interactions in two halogenated oxindoles. Comparative analyses of the interaction energy and the ...interaction properties were carried out for Br···Br, C-H···Br, C-H···O and N-H···O interactions. Employing Møller–Plesset second-order perturbation theory (MP2) and density functional theory (DFT), the basis set superposition error (BSSE) corrected interaction energy (Eint(BSSE)) was determined using a supramolecular approach. The Eint(BSSE) results were compared with interaction energies obtained by Quantum Theory of Atoms in Molecules (QTAIM)-based methods. Reduced Density Gradient (RDG), QTAIM and Natural bond orbital (NBO) calculations provided insight into possible pathways for the intermolecular interactions examined. Comparative analysis employing the electron density at the bond critical points (BCP) and molecular electrostatic potential (MEP) showed that the interaction energies and the relative orientations of the monomers in the dimers may in part be understood in light of charge redistribution in these two compounds.
Epigenetic changes, particularly histone compaction modifications, have emerged as critical regulators in the epigenetic pathway driving endothelial cell phenotype under constant exposure to laminar ...forces induced by blood flow. However, the underlying epigenetic mechanisms governing endothelial cell behavior in this context remain poorly understood. To address this knowledge gap, we conducted in vitro experiments using human umbilical vein endothelial cells subjected to various tensional forces simulating pathophysiological blood flow shear stress conditions, ranging from normotensive to hypertensive forces. Our study uncovers a noteworthy observation wherein endothelial cells exposed to high shear stress demonstrate a decrease in the epigenetic marks H3K4ac and H3K27ac, accompanied by significant alterations in the levels of HDAC (histone deacetylase) proteins. Moreover, we demonstrate a negative regulatory effect of increased shear stress on HOXA13 gene expression and a concomitant increase in the expression of the long noncoding RNA, HOTTIP, suggesting a direct association with the suppression of HOXA13. Collectively, these findings represent the first evidence of the role of histone‐related epigenetic modifications in modulating chromatin compaction during mechanosignaling of endothelial cells in response to elevated shear stress forces. Additionally, our results highlight the importance of understanding the physiological role of HOXA13 in vascular biology and hypertensive patients, emphasizing the potential for developing small molecules to modulate its activity. These findings warrant further preclinical investigations and open new avenues for therapeutic interventions targeting epigenetic mechanisms in hypertensive conditions.
HIGHLIGHTS
In vitro methodologies are employed as an initial approach to identify biomarkers associated with elevated shear stress in hypertension
Mechanosignaling mediated by oscillatory shear stress necessitates the involvement of epigenetic modifications, particularly histone‐mediated chromatin compression
Enhanced shear stress levels lead to a reduction in the overall abundance of acetylation marks, specifically H3K4 and H3K27, in endothelial cells
HOXA13 does not play a crucial role in the development of mechanosignaling induced by high shear stress
The data demonstrates a positive Pearson correlation between the long noncoding RNA HOTTIP and HOXA13
Oxy-fuel combustion is one of the promising options for carbon dioxide capture in future coal power plants. Radiative properties of combustion gases and heat transfer characteristics inside oxy-fuel ...furnaces are different from those found in air-fired furnace. Nowadays, few publications provide appropriate radiation property correlations for oxy-fuel conditions. The available correlations are based on previous versions of HITRAN database, which is not accurate for prediction of spectral intensities at high temperature in combustion applications or above 1000K. This paper considers the determination and evaluation of new correlations for the weighted-sum-of-gray-gases model to predict the radiative transfer in gases under oxy-fuel conditions. The new correlations are fitted from emittance charts calculated from the up-to-date HITEMP 2010 database for molar ratios of water vapor to carbon dioxide between 0.125 and 4, temperature range of 400–2500K, and pressure path-length varying from 0.001 to 60barm. The new correlations are validated by comparing the radiative source term with line-by-line calculations from HITEMP 2010 database for a one-dimensional slab system. The radiative transfer equation is solved with the discrete ordinate method.
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