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238 result(s) for "de Araújo Ferreira, Marcelo"
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Numerical Analysis of Reinforced Concrete Corbels Using Concrete Damage Plasticity: Sensitivity to Material Parameters and Comparison with Analytical Models
The Concrete Damage Plasticity (CDP) model is a widely used constitutive model to represent the non-linear behavior of concrete in numerical analysis. However, a limited number of studies compared the level of accuracy of numerical models with the main code provisions from the literature. In addition, the influence of CDP material parameters on the structural behavior of corbels was scarcely studied. This study proposes to evaluate the ability of numerical models using CDP to represent the structural behavior of corbels regarding the ultimate load, reinforcement deformation and failure mechanism. In addition, we compared the predictions of the numerical models with the ones from design code expressions regarding the ultimate capacity. For this, three test results of corbels from the literature were evaluated with numerical models using the CDP, as well as with analytical models from different code provisions. A sensitivity analysis—by changing the dilation angle (ψ) and shape factor (Kc)—was performed. The comparison between tested and predicted resistances with the proposed numerical modeling choices was equal to 1.04 with a coefficient of variation of 11%. On the other hand, the analytical models evaluated overestimated the corbel capacity by more than 62%, on average. Therefore, the proposed modeling choices provide better predictions of ultimate capacity than the evaluated analytical models and can be used to assess the corbel design under more complex boundary conditions.
Minute-scale detection of SARS-CoV-2 using a low-cost biosensor composed of pencil graphite electrodes
COVID-19 has led to over 3.47 million deaths worldwide and continues to devastate primarily middle- and low-income countries. High-frequency testing has been proposed as a potential solution to prevent outbreaks. However, current tests are not sufficiently low-cost, rapid, or scalable to enable broad COVID-19 testing. Here, we describe LEAD (Low-cost Electrochemical Advanced Diagnostic), a diagnostic test that detects severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within 6.5 min and costs $1.50 per unit to produce using easily accessible and commercially available materials. LEAD is highly sensitive toward SARS-CoV-2 spike protein (limit of detection = 229 fg·mL−1) and displays an excellent performance profile using clinical saliva (100.0% sensitivity, 100.0% specificity, and 100.0% accuracy) and nasopharyngeal/oropharyngeal (88.7% sensitivity, 86.0% specificity, and 87.4% accuracy) samples. No cross-reactivity was detected with other coronavirus or influenza strains. Importantly, LEAD also successfully diagnosed the highly contagious SARS-CoV-2 B.1.1.7 UK variant. The device presents high reproducibility under all conditions tested and preserves its original sensitivity for 5 d when stored at 4 °C in phosphate-buffered saline. Our low-cost and do-it-yourself technology opens new avenues to facilitate high-frequency testing and access to much-needed diagnostic tests in resource-limited settings and low-income communities.
TGF-β inhibitor therapy decreases fibrosis and stimulates cardiac improvement in a pre-clinical study of chronic Chagas’ heart disease
TGF-β involvement in Chagas disease cardiomyopathy has been clearly demonstrated. The TGF-β signaling pathway is activated in the cardiac tissue of chronic phase patients and is associated with an increase in extracellular matrix protein expression. The aim of this study was to investigate the effect of GW788388, a selective inhibitor of TβR1/ALK5, on cardiac function in an experimental model of chronic Chagas' heart disease. To this end, C57BL/6 mice were infected with Trypanosoma cruzi (102 parasites from the Colombian strain) and treated orally with 3mg/kg GW788388 starting at 120 days post-infection (dpi), when 100% of the infected mice show cardiac damage, and following three distinct treatment schedules: i) single dose; ii) one dose per week; or iii) three doses per week during 30 days. The treatment with GW788388 improved several cardiac parameters: reduced the prolonged PR and QTc intervals, increased heart rate, and reversed sinus arrhythmia, and atrial and atrioventricular conduction disorders. At 180 dpi, 30 days after treatment interruption, the GW3x-treated group remained in a better cardiac functional condition. Further, GW788388 treatment reversed the loss of connexin-43 enriched intercellular plaques and reduced fibrosis of the cardiac tissue. Inhibition of the TGF-β signaling pathway reduced TGF-β/pSmad2/3, increased MMP-9 and Sca-1, reduced TIMP-1/TIMP-2/TIMP-4, and partially restored GATA-6 and Tbox-5 transcription, supporting cardiac recovery. Moreover, GW788388 administration did not modify cardiac parasite load during the infection but reduced the migration of CD3+ cells to the heart tissue. Altogether, our data suggested that the single dose schedule was not as effective as the others and treatment three times per week during 30 days seems to be the most effective strategy. The therapeutic effects of GW788388 are promising and suggest a new possibility to treat cardiac fibrosis in the chronic phase of Chagas' heart disease by TGF-β inhibitors.
Baccharis reticularia DC. and Limonene Nanoemulsions: Promising Larvicidal Agents for Aedes aegypti (Diptera: Culicidae) Control
Baccharis reticularia DC. is a plant species from the Asteraceae family that is endemic to Brazil. Despite the great importance of Baccharis genus, no study has been carried out regarding either the phytochemical composition of B. reticularia or the evaluation of its larvicidal potential. Considering the intrinsic immiscibility of essential oils, this study shows larvicidal nanoemulsions containing the B. reticularia phytochemically characterized essential oil and its main constituent against Aedes aegypti. The major compound found was d-limonene (25.7%). The essential oil inhibited the acetylcholinesterase, one of the main targets of insecticides. The required hydrophile-lipophile balance of both nanoemulsions was 15.0. The mean droplet sizes were around 90.0 nm, and no major alterations were observed after 24 h of preparation for both formulations. After 48 h of treatment, the estimated LC50 values were 118.94 μg mL−1 and 81.19 μg mL−1 for B. reticularia essential oil and d-limonene nanoemulsions, respectively. Morphological alterations evidenced by scanning electron micrography were observed on the larvae treated with the d-limonene nanoemulsion. This paper demonstrated a simple and ecofriendly method for obtaining B. reticularia essential oil and d-limonene aqueous nanoemulsions by a non-heating and solvent-free method, as promising alternatives for Aedes aegypti control.
Surface electromyography signal processing and evaluation on respiratory muscles of critically ill patients: A systematic review
Surface Electromyography (sEMG) has been used to monitor respiratory muscle function and contractility in several clinical situations, however there is the lack of standardization for the analysis and processing of the signals. To summarize the respiratory muscles most assessed by sEMG in the critical care setting and the assessment procedure details employed on those muscles regarding electrode placement, signal acquisition, and data analysis. A systematic review of observational studies was registered on PROSPERO (number CRD42022354469). The databases included PubMed; SCOPUS; CINAHL, Web of Science and ScienceDirect. Two independent reviewers ran the quality assessment of the studies using the Newcastle-Ottawa Scale and Downs & Black checklists. A total of 311 participants were involved across the 16 studies, from which 62.5% (10) assessed the diaphragm muscle and 50% (8) assessed the parasternal muscle with similar electrode placement in both of them. We did not identify common patterns for the location of the electrodes in the sternocleidomastoid and anterior scalene muscles. 12/16 reported sample rate, 10/16 reported band-pass and 9/16 reported one method of cardiac-interference filtering technique. 15/16 reported Root Mean Square (RMS) or derivatives as sEMG-obtained variables. The main applicabilities were the description of muscle activation in different settings (6/16), testing of reliability and correlation to other respiratory muscles assessment techniques (7/16), and assessment of therapy response (3/16). They found sEMG feasible and useful for prognosis purposes (2/16), treatment guidance (6/16), reliable monitoring under stable conditions (3/16), and as a surrogate measure (5/16) in mechanically ventilated patients in elective or emergency invasive procedures (5/16) or in acute health conditions (11/16). The diaphragm and parasternal muscles were the main muscles studied in the critical care setting, and with similar electrodes placement. However, several different methods were observed for other muscles electrodes placement, sEMG signals acquisition and data analysis.
Assessment of the microbiological quality of natural mineral waters according to the manufacturing time of 20 L returnable packs in Brazil
This study aimed to assess the microbiological quality of natural mineral waters commercialized in 20 L returnable packs in Brazil by investigating the presence of bacteria and viruses in packs with different manufacturing times (Tm). With this purpose, 99 water samples from 33 lots (n = 3/batch) of 15 brands, obtained from packs with three intervals of Tm, were analyzed. Total coliforms (16.2%), Pseudomonas aeruginosa (9.9%), sulphite-reducing Clostridium (5.0%) and Escherichia coli (2.0%) were detected but enterococci and norovirus GII not. Regarding brands, 11 (73.3%) presented unsatisfactory results for at least one of the lots analyzed. Pseudomonas aeruginosa analysis revealed six sequence types and strains were susceptible to all antibiotics tested and were able to produce biofilms. Human adenovirus (4) and norovirus GI (9) were also identified in nine samples randomly selected. Natural mineral waters commercialized in 20 L packs with Tm ≥ 2 years presented more microbiological contamination (P ≤ 0.012) than ones with a Tm of 0–1 year or a Tm of 1–2 years. These results suggest that the validity period of reusable 20 L packs should be reduced or that they can no longer be reused.
Non-target molecular network and putative genes of flavonoid biosynthesis in Erythrina velutina Willd., a Brazilian semiarid native woody plant
Erythrina velutina is a Brazilian native tree of the Caatinga (a unique semiarid biome). It is widely used in traditional medicine showing anti-inflammatory and central nervous system modulating activities. The species is a rich source of specialized metabolites, mostly alkaloids and flavonoids. To date, genomic information, biosynthesis, and regulation of flavonoids remain unknown in this woody plant. As part of a larger ongoing research goal to better understand specialized metabolism in plants inhabiting the harsh conditions of the Caatinga, the present study focused on this important class of bioactive phenolics. Leaves and seeds of plants growing in their natural habitat had their metabolic and proteomic profiles analyzed and integrated with transcriptome data. As a result, 96 metabolites (including 43 flavonoids) were annotated. Transcripts of the flavonoid pathway totaled 27, of which EvCHI, EvCHR, EvCHS, EvCYP75A and EvCYP75B1 were identified as putative main targets for modulating the accumulation of these metabolites. The highest correspondence of mRNA vs. protein was observed in the differentially expressed transcripts. In addition, 394 candidate transcripts encoding for transcription factors distributed among the bHLH, ERF, and MYB families were annotated. Based on interaction network analyses, several putative genes of the flavonoid pathway and transcription factors were related, particularly TFs of the MYB family. Expression patterns of transcripts involved in flavonoid biosynthesis and those involved in responses to biotic and abiotic stresses were discussed in detail. Overall, these findings provide a base for the understanding of molecular and metabolic responses in this medicinally important species. Moreover, the identification of key regulatory targets for future studies aiming at bioactive metabolite production will be facilitated.
Epidermal growth factor receptor (EGFR) expression in the serum of patients with triple-negative breast carcinoma: prognostic value of this biomarker
Epidermal growth factor receptor (EGFR) overexpression has been considered a poor prognostic factor in breast cancer. A prospective study of 206 women with breast cancer analysed by stages (I, II, III and IV) and by immunohistochemical subtype (Luminal A, Luminal B, HER2+ and triple-negative (TN)); 89 healthy controls with normal recent mammography were included. The EGFR measured in the serum (sEGFR) was detected by the Enzyme-Linked Immunosorbent Assay (ELISA) method (R&D Systems kit DY231) collected by blood before any treatment in patients. Kaplan-Meier method and Cox regression were carried out to obtain the prognostic value, considering significance if p < 0.05. With a median follow-up of 36.6 months, 47 deaths occurred. Multivariable Cox regression showed difference of overall survival (OS) associated with sEGFR levels (sEGFR ≤ or > 47.8 ng/mL) in patients with TN cancers, but not of Luminal A, Luminal B or HER2+ subtypes; adjusted by stage, the death risk increased by approximately 415% [hazard ratio (HR): 5.149 (1.900-13.955), p = 0.001] for patients with sEGFR > 47.8 ng/mL compared to patients with a lower sEGFR value. There was no significant correlation of sEGFR with staging, histological tumour grade (G1/G2/G3), Ki67 (< or ≥14%) or body mass index. Increased sEGFR expression in patients with TN tumours is a significant predictor of lower OS and its quantification is inexpensive and straightforward.
Mitigation of chilling injury in sweet potato roots subjected to low-temperature conditioning
In many plant tissues, low-temperature conditioning (LTC) has been used to induce postharvest adaptive responses to overcome chilling injury (CI) consequences. This study aimed to investigate whether LTC is effective in reducing the incidence of chilling injury (CI) in sweet potato cultivars. Sweet potato roots BRS Cuia and BRS Rubissol were submitted to cold storage (6 °C or 13 °C) and LTC (10 °C for 7 d, followed by second storage at 6 °C). LTC increased the tolerance of sweet potato roots to CI via antioxidant system activation, mainly in cv. BRS Rubissol, which was markedly associated with higher content of both total soluble phenolics and proline, as well as increased activity of phenylalanine ammonium lyase. Moreover, no either external or internal injuries were observed in the LTC roots, maintaining the quality for processing, which indicates that the LTC is effective in mitigating chilling injury in Brazilian sweet potato cultiva
Expansion of Oropouche virus in non-endemic Brazilian regions: analysis of genomic characterisation and ecological drivers
Oropouche virus (OROV) is an arbovirus endemic in the Amazon region that closely resembles other arboviruses in terms of human disease, leading to potential misdiagnoses. The virus ecology has mostly restricted its occurrence to the Amazon biome; however, after a large 2023–24 OROV epidemic in the Brazilian Amazon region, outbreaks are being reported across Brazil and in other countries in Latin America. Here, we investigate the OROV spread outside Amazonia. In this genomic and epidemiological study, OROV cases from January, 2023, to July, 2024, provided by the General Coordination of Public Health Laboratories of Brazil on Aug 1, 2024, were compared by geographical location (Amazon vs non-Amazon) and municipal population size, and a linear mixed model was employed to assess the relationship between agricultural area size and cases. OROV-positive samples from central laboratories of five non-Amazonian Brazilian states were sequenced using an amplicon-based approach. Bayesian phylogeographical analysis was performed with near full-length viral genomes, incorporating individual travel histories when relevant. The estimated dates of viral introductions in each sampled location were then contextualised with public epidemiological data. Epidemic data show that outside the Amazon region, OROV cases frequency was 3·9-times higher in small municipalities than in large municipalities. The planted areas of some agricultural products, such as banana plantations, were positively correlated (r=0·39, p<0·0001) with OROV cases. The linear mixed model revealed that, besides banana, cassava also has larger (p<0·05) planted areas in municipalities with OROV cases when compared with those with no cases. The phylogenetic analysis of 32 new OROV genomes reconstructed multiple exportation events of the newly identified reassortant lineage from the Amazon to other Brazilian regions between January and March, 2024. At least three of the previously described OROV phylogenetic clades circulating in the Amazon were the source of viral introductions. Molecular clock analysis estimated that viral introductions happened from 50 days to 100 days before detecting the outbreaks in each state. Our results confirm that the novel OROV reassortant lineage spread from the Amazon to other regions in early 2024, successfully establishing local transmission. The fact that outbreaks were observed in small municipalities, instead of large urban centres, suggests that local ecological conditions that are ideal for OROV vector occurrence, such as the banana plantation environment, might be important factors driving its spread in Brazil. DECIT, CNPq, FAPEAM, and Inova-Fiocruz. For the Portuguese translation of the abstract see Supplementary Materials section.