This paper presents an approach developed to quantify the chaotic behavior for the characterization of electromechanical systems. A technique named Signal Analysis based on Chaos using Density of ...Maxima (SAC-DM) is presented. This technique uses a simple peak counting algorithm in the time domain of the current signal to detect faults. To demonstrate the potential of SAC-DM, an experiment is presented where a small brushless direct current (BLdc) motor at different speeds, with a regular and an unbalanced propeller, is used. The results demonstrate that the SAC-DM was able to detect the speed of the BLdc motor in 99.16% of the cases, and to identify the unbalanced system in 99.79% of the cases, when the speed is at 50%.
The present study aimed at investigating the influence of the electrodeposition current density and pH of the plating solution on chemical composition, electrodeposition current efficiency and on the ...roughness factor of the electrodeposited Co-Mo coatings. The coatings with higher roughness factor were evaluated as cathodes for hydrogen evolution reaction in alkaline medium. The electrodeposition current densities were 30 mA cm−2, 45 mA cm−2 and 60 mA cm−2 and the values of pH of the plating solutions were 6, 7 and 8. The two-level and centre-point factorial design was applied. Coatings showed cracks and amorphous structures. The pH had a positive effect on the Mo percentage and on the roughness factor of the coatings. The current density had the highest effect on the current efficiency and electroactive area of the coatings. Increasing the value of this parameter, the current efficiency decreased from 31.63% to 17.65% and roughness factor presented relative increase of 27.53–78.74. The Volmer reaction was the determining step and the apparent activation energy was 18.40 kJ mol−1 in the hydrogen evolution reaction.
•Mo content also contributes to increase in the number of cracks in the coatings.•The Mo can be present as agglomerates in the lattice of Co.•The current density had the highest effect on the coatings electroactive areas.•The Volmer reaction was the determining step in the hydrogen evolution reaction.
Different antioxidants have been tested to improve sperm quality, but distinct and consistent beneficial effects are lacking. The objective of this study was to evaluate whether the addition of ...different concentrations of the antioxidant Trolox C and ascorbic acid before cryopreservation could improve the binding of sperm to chicken egg perivitelline membrane (PM) after cryopreservation. Three ejaculates of ram were split and diluted with Tris egg yolk diluent to a final concentration of 200×106cellsmL-1, and after, the ejaculates were divided into 5 tubes. Each tube received one of the following antioxidants: control, no antioxidant; 200μM of Trolox C; 300μM of Trolox C; 0.05% of ascorbic acid; and 0.25% of ascorbic acid. The samples were cooled to 5°C/2h, packaged into 0.5-mL straws, and frozen in static LN vapor for 15min before being plunged into LN. Straws were thawed (37°C/30s). The motility was determined using computer-assisted semen analysis. For PM binding test, PM was put in tubes with 1mL of TALP and inseminated with 50000 sperm. The PM and sperm were incubated for 90min at 37°C in an atmosphere of 5% CO2 in air, and 20min before the end of the incubation time, 10μL of Hoechst 33342 was added in each treatment. After each PM was washed 5 times in TALP, placed under the coverslip on a slide, and evaluated by fluorescence microscopy at 400×. Spermatozoa were counted in 6 random fields of each piece of PM. Percentage data were transformed using arcsine prior analysis. Treatment differences were determine by analysis of variance and Tukey test. The total and progressive motility of sperm treated with 0.25% ascorbic acid Trolox C was higher (64.5 and 45%) than 100μM of Trolox C (61.9 and 42.6%) and 200μM of Trolox C (64.3 and 46.7%) and control (59.8 and 39.6%; P<0.05), respectively. The binding test was higher when using 0.25% of ascorbic acid (155.73 cells; P<0.05) compared with other treatments. Addition of 0.25% ascorbic acid to ram sperm before cryopreservation improved cell cryosurvival rates.
A novel technique named Signal Analysis based on Chaos using Density of Maxima (SAC-DM) is presented to analyze Brushless Direct Current (BLDC) motors behavior. These motors are vastly used in ...electric vehicles, especially in Drones. The proposed approach is compared with the traditional Fast-Fourier Transform (FFT) and the experiments analyzing a BLDC motor of a drone demonstrates similar results but computationally simpler than that. The main contribution of this technique is the possibility to analyze signals in time domain, instead of the frequency domain. It is possible to identify working and faulty behavior with less computational resources than the traditional approach.
A comparative investigation was carried out with electrodeposited Ni-W and Ni-Mo-W coatings to evaluate the influence of Mo content on the corrosion resistance. Corrosion tests were carried out by ...potentiodynamic linear polarization, electrochemical impedance spectroscopy and open circuit monitory, in NaCl solution. Ni-W and Ni-Mo-W coatings were obtained by electrodeposition and Mo content in the layer increased with the molybdenum ion concentration in the electrolyte. Cracked and non-cracked coatings were obtained resulting in nanocrystalline or amorphous coatings. Finally, the addition of Mo improved the corrosion resistance of the Ni-W based coatings in neutral medium.
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The secondary metabolites of the aerial parts of Zornia brasiliensis Vogel, Fabaceae, and the biological activity of one of these secondary metabolites were characterized in this ...study. A phytochemical investigation was performed using chromatographic techniques including analytical and preparative reverse-phase HPLC column sequences, which resulted in the isolation of fourteen compounds: one previously undescribed C-glycosylated dihydrochalcone (zornioside), one cyclitol (D-pinitol), one glycosylated megastigmane (roseoside) and eleven phenolic compounds: 7-methoxyflavanone, 7,4′-dimethoxyisoflavone, medicarpin, 2′-4′-dihydroxychalcone, onionin, isoorientin-3′-O-methyl ether, isovitexin, glycosylated (Z)-O-coumaric acid, glycosylated (E)-O-coumaric acid, dihydromelilotoside, and isoorientin. The structures of the isolated compounds were determined based on 1D and 2D-NMR, HRESIMS, IR and CD spectroscopic analyses. The cytotoxic activity of zornoside was assessed against tumor cell lines (MCF-7, HCC1954, T-47D, 4T1, HL60), and a non-tumor cell line (RAW264.7) using MTT assay. The compound zornioside was selectively cytotoxic for HL60 leukemia cells (IC50: 37.26μM).
Casos de intoxicações com plantas do gênero Crotalaria (Leguminosae) em humanos, e principalmente em animais, tem sido amplamente descritos, com o comprometimento do SNC em animais mais sensíveis, ...como equídeos. Esse estudo objetivou investigar os efeitos diretos do alcalóide pirrolizidínico Monocrotalina (MCT), principal toxina da C. retusa, em culturas primárias de astrócitos corticais de ratos. Foram testadas concentrações entre 0,1-500µM da MCT no período de 24 e 72h. O teste do MTT revelou que a MCT não mostrou toxicidade em astrócitos. A coloração de Rosenfeld permitiu evidenciar que os astrócitos tratados com 10-500µM MCT por 72h, apresentaram o corpo celular contraído e desenvolveram finos prolongamentos de tamanho variável; este efeito foi dose-dependente, e verificado em até cerca de 80% das células tratadas com 500µM MCT. Modificações na expressão da GFAP foram verificadas por marcação imunocitoquímica e western blot, especialmente após 72h de tratamento: a MCT induziu, de forma dose dependente, modificação na distribuição da GFAP, que ficou mais localiza na região peri-nuclear, e uma redução de cerca de 40% nos níveis de expressão dessa proteína foi verificada em todas as concentrações testadas. A coloração da cromatina nuclear com Hoechst-33258 revelou que a presença de astrócitos com núcleos picnóticos ou múltiplos nas culturas tratadas com 1-500µM MCT. Estes resultados indicam uma ação direta da MCT em astrócitos corticais de ratos, alterando a morfologia e o crescimento celular, e sugerem que a resposta astrocitária a este alcalóide pode estar relacionada aos danos no SNC observados em animais intoxicados.
Our understanding of the specific aspects of vascular contributions to dementia remains unclear.
We aim to identify the correlates of incident dementia in a multi-ethnic cardiovascular cohort.
A ...total of 6806 participants with follow-up data for incident dementia were included. Probable dementia diagnoses were identified using hospitalization discharge diagnoses according to the International Classification of Diseases Codes (ICD). We used Random Forest analyses to identify the correlates of incident dementia and cognitive function from among 198 variables collected at the baseline MESA exam entailing demographic risk factors, medical history, anthropometry, lab biomarkers, electrocardiograms, cardiovascular magnetic resonance imaging, carotid ultrasonography, coronary artery calcium and liver fat content. Death and stroke were considered competing events.
Over 14 years of follow-up, 326 dementia events were identified. Beyond age, the top correlates of dementia included coronary artery calcification, high sensitivity troponin, common carotid artery intima to media thickness, NT-proBNP, physical activity, pulse pressure, tumor necrosis factor-α, history of cancer, and liver to spleen attenuation ratio from computed tomography. Correlates of cognitive function included income and physical activity, body size, serum glucose, glomerular filtration rate, measures of carotid artery stiffness, alcohol use, and inflammation indexed as IL-2 and TNF soluble receptors and plasmin-antiplasmin complex.
In a deeply phenotyped cardiovascular cohort we identified the key correlates of dementia beyond age as subclinical atherosclerosis and myocyte damage, vascular function, inflammation, physical activity, hepatic steatosis, and history of cancer.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The crude venom of the giant ant
is a cocktail of polypeptides and organic compounds that shows antiparasitic effects against
, the causative agent of Chagas disease. In order to investigate the ...venom-derived components responsible for such antitrypanosomal activity, four dinoponeratoxins (DnTxs) were identified, namely M-PONTX-Dq3a, -Dq3b, -Dq3c and -Dq4e, that are diverse in size, net charge, hydrophobicity and propensity to interact with eukaryote cell membranes. These peptides were tested against epimastigote, trypomastigote and amastigote forms of benznidazole (Bz)-resistant Y strain of
and in mammalian host cells. The M-PONTX-Dq3a and -Dq4e inhibited all developmental forms of
, including amastigotes, the responsible form for the maintenance of infection on chronic phase of the disease. The M-PONTX-Dq3a showed the highest selectivity index (SI) (80) and caused morphological alterations in
, as observed by scanning electron microscopy (SEM), and induced cell death through necrosis, as seen by multiparametric flow cytometry analysis with specific biochemical markers. Altogether, the
venom appears as a source for the prospection of trypanocidal peptides and the M-PONTX-Dq3a arises as a candidate among the dinoponeratoxin-related peptides in the development of compounds against Chagas disease.
This study proposes to characterize the effect of long-term thermal cycling on transformation temperatures and thermodynamic parameters of polycrystalline CuAlBeCr shape memory alloy. Structural, ...morphological and thermal characterizations were performed. The samples were submitted up to 1000 cycles using a dual-bath thermal cycler apparatus. The results show that the thermal cycling has a considerable impact on the transformation behavior of the alloy. Up to 500 cycles, the alloy experienced a one-stage reverse martensitic transformation; after this, it was split into two reactions. From 100 cycles, an increase in temperature ranges (
A
f
-
A
s
) values of the reverse martensitic transformation was observed, associated with the increase in elastic energy. Our study expands the spectrum of knowledge regarding thermal and structural properties, for CuAlBe system alloys, indicating the thermal cycling conditions to which the alloy must be subjected in order to preserve the characteristics required in a given practical application.
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