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Severe plastic deformation through high-pressure torsion is used to refine the grain structure of the Mg–Al–Zn alloy down to ~ 140 nm and low temperature annealing is used to produce samples with different grain sizes, within the ultrafine range. The mechanical behavior is investigated using different testing techniques including microhardness, indentation creep, plane-strain compression, creep, and miniaturized tensile testing. The results allow a comprehensive analysis of the deformation mechanism. It is shown that the relationship between the flow stress and the inverse of the square root of the grain size is not linear in the ultrafine grained range and depends on temperature and strain rate. Grain refinement hardening and grain refinement softening can be observed at different temperatures and strain rates. There is an increase in strain-rate sensitivity and a decrease in apparent activation volume with decreasing the grain size. These experimental observations agree with the deformation mechanism of grain boundary sliding provided the thermal contribution for the threshold stress is taken into account.

Cold angular rolling process (CARP) has emerged as a potential continuous severe plastic deformation technique enabling the processing of bulk metal sheets with improved mechanical properties. The CARP technique involves a combination of cold rolling of a sheet by a single rotation roller followed by equal-channel angular pressing of the sheet passing through a bent channel. The present work uses finite element method (FEM) to model CARP by considering processing conditions, including different friction values and processing velocities for different copper and stainless steel alloys. The simulations reveal the influence of these processing parameters on distributions of strain, strain rate, stress (in both the metal sheet and the CARP tool), temperature, and torque requirements through one pass of CARP on the metal sheets. The modeling results are validated by the experimental characterization of the hardness distribution and microstructure after CARP on a copper sheet. The results from FEM are used to estimate the energy incorporated into different metal alloys at various processing conditions. Finally, this study discusses the feasibility of scaling up the CARP technique. Graphical abstract

There is a great interest in improving mechanical testing of small samples produced in the laboratory. Plane strain compression is an effective test in which the workpiece is a thin sheet. This provides great potential for testing samples produced by high-pressure torsion. Thus, a custom tool was designed with the aim to test 10 mm diameter discs processed by this technique. Finite element analysis is used to evaluate the deformation zone, stress and strain distribution, and the accuracy in the estimation of stress–strain curves. Pure magnesium and a magnesium alloy processed by high-pressure torsion are tested using this custom-made tool. The trends observed in strength and ductility agree with trends reported in the literature for these materials.

There has been a great interest in developing zinc-based composites for biological applications. Mixing bioactive particles and obtaining a well-dispersed structure is not straight forward though. The present study reports a novel processing route in which zinc particles are mixed with hydroxyapatite and bioactive glass particles and consolidated at room temperature using high-pressure torsion. The composites display good dispersion of second phase particles, enhanced strength and an increased corrosion rate in the Hank’s balanced salt solution. The incorporation of these particles can be used to tailor the corrosion rate of zinc. It is shown that the surface layer of the corrosion product in the zinc-bioactive particle composites is richer in calcium and phosphorous than the pure zinc counterpart.

The high-pressure torsion processing technique was used to consolidate and process magnesium-based chips. Chips were prepared by machining commercially pure magnesium and a magnesium alloy AZ91 separately. Optical microscopy and microhardness measurements showed good consolidation of pure magnesium. The magnesium alloy continued to exhibit the boundaries between the chips even after 5 turns of HPT suggesting poor bonding. The results show that soft chips are easier to consolidate through HPT than harder alloys.

Continuous monitoring of forest disturbance on tropical forests is a fundamental tool to support proactive preservation actions and to stop further destruction of native vegetation. Currently most of the monitoring systems in operation are based on optical imagery, and thus are flaw-prone on areas with frequent cloud cover. As this, several Synthetic Aperture Radar (SAR)-based systems have been developed recently, aiming all-weather disturbance detection. This article presents the main aspects and the results of the first year of operation of the SAR based Near Real-Time Deforestation Detection System (DETER-R), an automated deforestation detection system focused on the Brazilian Amazon. DETER-R uses the Google Earth Engine platform to preprocess and analyze Sentinel-1 SAR time series. New images are treated and analyzed daily. After the automated analysis, the system vectorizes clusters of deforested pixels and sends the corresponding polygons to the environmental enforcement agency. After 12 months of operational life, the system has produced 88,572 forest disturbance warnings. Human validation of the warning polygons showed a extremely low rate of misdetections, with less than 0.2% of the detected area corresponding to false positives. During the first year of operation, DETER-R provided 33,234 warnings of interest to national monitoring agencies which were not detected by its optical counterpart DETER in the same period, corresponding to an area of 105,238.5 ha, or approximately 5% of the total detections. During the rainy season, the rate of additional detections increased as expected, reaching 8.1%.

Annona neoinsignis H. Rainer (Annonaceae) is a tree native to the Amazon rainforest. Its fruits are also suitable for human consumption in their natural state or are processed to make desserts. In this work, we characterized the chemical composition of the essential oil (EO) from the leaves of A. neoinsignis and evaluated its anti-liver-cancer potential via in vitro and in vivo approaches. Chemical composition analysis revealed β-elemene, (E)-caryophyllene, germacrene D, and germacrene B as the main constituents. The EO had IC50 values ranging from 12.28 to 37.50 μg/mL for B16-F10 cells and MCF-7 cells, whereas an IC50 value of >50 μg/mL was found for noncancerous MRC-5 cells. DNA fragmentation, YO-PRO-1 staining, and loss of mitochondrial transmembrane potential were detected in EO-treated HepG2 cells, indicating the induction of apoptosis. Significant in vivo growth inhibition of 53.7% was observed in mice bearing HepG2 cell xenografts treated with EO at a dosage of 40 mg/kg. These data suggest that EO from A. neoinsignis leaves is a drug source for liver cancer.

This study evaluated the apical sealing ability and bioactivity of an experimental gutta-percha containing niobium phosphate bioglass. Thirty-six human premolars were endodontically prepared and divided into three groups: GPC—filling with conventional gutta-percha; GBC—filling with bioceramic gutta-percha (EndoSequence BC); GNB—filling with experimental gutta-percha containing niobophosphate. Teeth were stored in tubes containing 2 mL of simulated body fluid (SBF) solution in an oven for 30 days. Then, the samples were immersed in lanthanum nitrate solution and analyzed for apical nanoleakage (NI) with a scanning electron microscope (SEM/EDS) and transmission electron microscope (TEM). Gutta-percha specimens were immersed for 28 days (SBF) and analyzed in SEM/EDS and X-ray diffraction (XRD) to assess bioactivity. NI data originated from the SEM/EDS were analyzed using the Kruskal–Wallis test (α = 5%). NI data originated from TEM and bioactivity were descriptively reported. Statistical analysis did not detect a significant difference between groups (p = 0.13) for NI. In the bioactivity analysis, an abundant layer of hydroxyapatite was identified only in the surface of the GNB group samples. The gutta-percha containing niobophosphate bioglass promoted an apical sealing similar to EndoSequence BC, in addition to demonstrating bioactivity through the deposition of hydroxyapatite on the surface of the material after immersion in SBF.

Acetylcholinesterase (AChE) acts on the hydrolysis of acetylcholine, rapidly removing this neurotransmitter at cholinergic synapses and neuromuscular junctions as well as in neuronal growth and differentiation, modulation of cell adhesion (“electrotactins”) and aryl-acylamidase activity (AAA). This enzyme is also found in erythrocyte, as 160 kDa dimer that anchors to the plasma membrane via glycophosphatidylinositol. The function of this enzyme in erythrocytes has not yet been elucidated; however, it is suspected to participate in cell-to-cell interactions. Here, a review on erythrocyte AChE characteristics and use as biomarker for organophosphorus and carbamate insecticides is presented since it is the first specific target/barrier of the action of these pesticides, besides plasma butyrylcholinesterase (BChE). However, some past and current methods have disadvantages: (a) not discriminating the activities of AChE and BChE; (b) low accuracy due to interference of hemoglobin in whole blood samples. On the other hand, extraction methods of hemoglobin-free erythrocyte AChE allows: (a) the freezing and transporting of samples; (b) samples free of colorimetric interference; (c) data from only erythrocyte AChE activity; (d) erythrocyte AChE specific activity presents higher correlation with the central nervous system AChE than other peripheral ChEs; (e) slow spontaneous regeneration against anti-ChEs agents of AChE in comparison to BChE, thus increasing the chances of detecting such compounds following longer interval after exposure. As monitoring perspectives, hemoglobin-free methodologies may be promising alternatives to assess the degree of exposure since they are not influenced by this interfering agent.

Intestinal mucositis is a common side effect of irinotecan-based anticancer regimens. Mucositis causes cell damage, bacterial/endotoxin translocation and production of cytokines including IL-1 and IL-18. These molecules and toll-like receptors (TLRs) activate a common signaling pathway that involves the Myeloid Differentiation adaptor protein, MyD88, whose role in intestinal mucositis is unknown. Then, we evaluated the involvement of TLRs and MyD88 in the pathogenesis of irinotecan-induced intestinal mucositis. MyD88-, TLR2- or TLR9-knockout mice and C57BL/6 (WT) mice were given either saline or irinotecan (75 mg/kg, i.p. for 4 days). On day 7, animal survival, diarrhea and bacteremia were assessed, and following euthanasia, samples of the ileum were obtained for morphometric analysis, myeloperoxidase (MPO) assay and measurement of pro-inflammatory markers. Irinotecan reduced the animal survival (50%) and induced a pronounced diarrhea, increased bacteremia, neutrophil accumulation in the intestinal tissue, intestinal damage and more than twofold increased expression of MyD88 (200%), TLR9 (400%), TRAF6 (236%), IL-1β (405%), IL-18 (365%), COX-2 (2,777%) and NF-κB (245%) in the WT animals when compared with saline-injected group (P<0.05). Genetic deletion of MyD88, TLR2 or TLR9 effectively controlled the signs of intestinal injury when compared with irinotecan-administered WT controls (P<0.05). In contrast to the MyD88-/- and TLR2-/- mice, the irinotecan-injected TLR9-/- mice showed a reduced survival, a marked diarrhea and an enhanced expression of IL-18 versus irinotecan-injected WT controls. Additionally, the expression of MyD88 was reduced in the TLR2-/- or TLR9-/- mice. This study shows a critical role of the MyD88-mediated TLR2 and TLR9 signaling in the pathogenesis of irinotecan-induced intestinal mucositis.