Search

This study investigated the impact of adding graphene oxide (GO) and iron oxide (II) (Fe3O4) nanoparticles individually and in combination on the morphology, thermo-mechanical, and dielectric properties of a Polypropylene/High-Density Polyethylene (PP/HDPE) blend. By adding these nanoparticles separately or as a mixture, we can determine if both mechanisms have a synergistic effect and how they impact the dielectric constant values of their nanocomposites. The nanoparticle mixture was prepared in both an alkaline and a neutral medium. The mixture in the alkaline medium contained lower quantities of iron nanoparticles than in the neutral medium, and they were localized on the surface of GO. The nanocomposites showed significant differences in dynamic-mechanical and dielectric properties. The system with Fe3O4 exhibited a higher storage modulus, while the system with GO had a higher dielectric constant. However, no synergistic effect was observed in the nanoparticle mixtures.

This work studied the individual and combined addition of natural (MMT-Na) and modified (MMT-30B) nanoclays, and carbon nanotubes (CNTs) to a poly (hexamethylene isophthalamide co-terephthalamide) (aPA)/styrene-ethylene/ butylene-styrene (SEBS) blend grafted with maleic anhydride. Their effects on the blend's morphology, thermo-mechanical properties, and flammability were evaluated. Morphological analysis showed that both clays were located in the aPA matrix, with the MMT-Na as agglomerates and the MMT-30B intercalated with exfoliated regions. The CNTs were dispersed and randomly oriented in the aPA matrix. Data obtained through dynamic-mechanical analysis (DMA) showed that adding 1.0% MMT-30B and 1.0% CNT increased the storage modulus (E') by 26% and 27%, respectively, while adding both 0.5% MMT-30B and 0.5% CNT increased E' by 38%, suggesting synergy between the nanoparticles related to mechanical properties. Regarding flammability, since the first burn timing (tl) could not be obtained, none of the samples could be classified according to the UL94 standard. However, qualitatively, a better flammability performance was noticed for the nanocomposites than for the pure blend. KEYWORDS carbon Nanotube, clay, dynamic-mechanical properties, flammability, polyamide, SEBS, 1 | INTRODUCTION Adding nanoparticles to immiscible polymer blends can affect the resulting material's properties in several ways, improving mechanical, thermal, electrical, barrier, and flame retardancy characteristics, among others. [1-5] [...]

Maternal autoantibodies can be transmitted diaplacentally, with potentially deleterious effects on neurodevelopment. Synapsin 1 (SYN1) is a neuronal protein that is important for synaptic communication and neuronal plasticity. While monoallelic loss of function (LoF) variants in the SYN1 gene result in X-linked intellectual disability (ID), learning disabilities, epilepsy, behavioral problems, and macrocephaly, the effect of SYN1 autoantibodies on neurodevelopment remains unclear. We recruited a clinical cohort of 208 mothers and their children with neurologic abnormalities and analyzed the role of maternal SYN1 autoantibodies. We identified seropositivity in 9.6% of mothers, and seropositivity was associated with an increased risk for ID and behavioral problems. Furthermore, children more frequently had epilepsy, macrocephaly, and developmental delay, in line with the SYN1 LoF phenotype. Whether SYN1 autoantibodies have a direct pathogenic effect on neurodevelopment or serve as biomarkers requires functional experiments.

Copyright of Journal of Applied Polymer Science is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Multiwall carbon nanotubes (CNT) or montmorillonite clay (MMT-30B) were added to a poly(hexamethylene isophthalamide-co-terephthalamine) (an amorphous polyamide - aPA) and styrene-ethylene/butylene-styrene graphitized with maleic anhydride (SEBS) blend, in different concentrations, in order to investigate the morphology, thermal properties and flammability behavior. Different nanoparticle localizations in the phase blend were observed through transmission electronic microscopy. CNT nanoparticles are localized in SEBS phase, and MMT-30B nanoparticles in aPA phase. No significant changes were observed on transition temperatures and thermal stability with both nanoparticle additions. However, a slight increase on storage modulus for clay nanocomposites and a slight reduction for carbon nanotube nanocomposites were observed, due to their different phase localizations. Regarding flammability, CNT nanocomposites showed better performance as a flame retardant when compared to samples with MMT-30B. Although the MMT30B nanocomposites could not be classified according to the UL-94 criteria, no dripped flaming particles were observed, due to the a char barrier formation on the polymer surface. The CNT nanocomposites were classified according to the UL-94 criteria as V-2. The CNTs selective localization on the SEBS phase decreases its heat-release rate, but no interconnected network structure was formed in the matrix to suppress the dripping flaming particles. KEYWORDS blends, carbon nanotube, clay, flammability, polyamide, SEBS, thermal properties, 1 | INTRODUCTION Amorphous polyamides (aPA) have a lower processing temperature and moisture absorption and a better chemical resistance and thermal stability when compared to semi-crystalline polyamides. [1,2] However, they [...]

A two-dimensional multichannel seismic reflection profile acquired in the Madeira Abyssal Plain during June 2016 was used in a modeling workflow comprising seismic oceanography processing, geostatistical inversion and Bayesian classification to predict the probability of occurrence of distinct water masses. The seismic section was processed to image in detail the fine scale structure of the water column using seismic oceanography. The processing sequence was developed to preserve, as much as possible, the relative seismic amplitudes of the data and enhance the shallow structure of the water column by effectively suppressing the direct arrival. The migrated seismic oceanography section shows an eddy at the expected Mediterranean Outflow Water depths, steeply dipping reflectors, which indicate the possible presence of frontal activity or secondary dipping eddy structures, and strong horizontal reflections between intermediate water masses suggestive of double diffuse processes. We then developed and applied an iterative geostatistical seismic oceanography inversion methodology to predict the spatial distribution of temperature and salinity. Due to the lack of contemporaneous direct measurements of temperature and salinity we used a global ocean model as spatial constraint during the inversion and nearby contemporaneous ARGO data to infer the expected statistical properties of both model parameters. After the inversion, Bayesian classification was applied to all temperature and salinity models inverted during the last iteration to predict the spatial distribution of three distinct water masses. A preliminary interpretation of these probabilistic models agrees with the expected ocean dynamics of the region.

The article in the Journal of Cell Biology discusses recent findings that synaptotagmin-1, a key calcium sensor at synapses, forms biomolecular condensates, shedding light on a new layer of regulation in synaptic vesicle exocytosis. Through computational and experimental approaches, researchers discovered that synaptotagmin-1 condensates play a crucial role in regulating calcium-triggered synaptic vesicle fusion. These findings provide valuable insights into the molecular mechanisms underlying synaptotagmin-1-mediated exocytosis, offering new avenues for further research in this essential cellular process. [Extracted from the article]

Abstract Aims: The present study investigated the effect of different frequencies (three and five times a week) on electron transport chain and oxidative stress after 8 weeks of run training. Methods: Eighteen male mice (CF1, 30-35g) were distributed into the following groups (n=6): untrained (UT); trained three-time per week (T3) and trained five- time per week (T5). All training sessions were at the same intensity and duration (45min/day) in a treadmill for small animals. Forty-eight hours after the last training session, the animals were killed by decapitation and quadriceps (red portion) was removed and stored at -70ºC. Succinate dehydrogenase (SDH), complexes I, II, II-III, IV and hydroperoxides were measured. Results: Training sessions for five times per week were more effective in increasing the mitochondrial respiratory chain enzyme activities (SDH, complexes I, II, II-III, IV) as well as in decreasing the formation hydroperoxides than sessions performed for three times training per week (p

The objective of the present study was to investigate the effects of eccentric training on the activity of mitochondrial respiratory chain enzymes, oxidative stress, muscle damage, and inflammation of skeletal muscle. Eighteen male mice (CF1) weighing 30-35 g were randomly divided into 3 groups (N = 6): untrained, trained eccentric running (16°; TER), and trained running (0°) (TR), and were submitted to an 8-week training program. TER increased muscle oxidative capacity (succinate dehydrogenase and complexes I and II) in a manner similar to TR, and TER did not decrease oxidative damage (xylenol and creatine phosphate) but increased antioxidant enzyme activity (superoxide dismutase and catalase) similar to TR. Muscle damage (creatine kinase) and inflammation (myeloperoxidase) were not reduced by TER. In conclusion, we suggest that TER improves mitochondrial function but does not reduce oxidative stress, muscle damage, or inflammation induced by eccentric contractions.

The objective of the present study was to investigate the effects of eccentric training on the activity of mitochondrial respiratory chain enzymes, oxidative stress, muscle damage, and inflammation of skeletal muscle. Eighteen male mice (CF1) weighing 30-35 g were randomly divided into 3 groups (N = 6): untrained, trained eccentric running (16°; TER), and trained running (0°) (TR), and were submitted to an 8-week training program. TER increased muscle oxidative capacity (succinate dehydrogenase and complexes I and II) in a manner similar to TR, and TER did not decrease oxidative damage (xylenol and creatine phosphate) but increased antioxidant enzyme activity (superoxide dismutase and catalase) similar to TR. Muscle damage (creatine kinase) and inflammation (myeloperoxidase) were not reduced by TER. In conclusion, we suggest that TER improves mitochondrial function but does not reduce oxidative stress, muscle damage, or inflammation induced by eccentric contractions.

During the muscle contraction induced by exercises there is an increase in the reactive oxygen species production, causing oxidative stress in several organs, including liver and heart. The exercise may can increases antioxidant defenses and decrease oxidative stress in these organs. However, the number of the sessions a week necessary to improve the parameters of oxidative stress is not to well defined. The aim of the study was to investigate the frequency effects of exercise performed two and three times a week on changes in biomarkers of oxidative stress in the liver and heart. Were used 18 male mice (CF1), young (30 to 35g) and divided into groups (n=6/group): not trained (NT) trained twice a week (T2) and trained three times a week (T3). The animals were subjected to training for eight weeks. Forty-eight hours after the last session, the animals were killed. The liver and heart were removed and stored in - 70°C. Were analyzed the thiobarbituric acid reactive substances, protein carbonyls, content of total thiols, superoxide dismutase, catalase and glutathione peroxidase. Our findings showed that the group T3 reduced oxidative damage. There was increase in content of total thiols, superoxide dismutase and catalase in the T3 group when compared to NT. The glutathione peroxidase activity showed no significant difference between groups. This study demonstrated that only the frequency of training performed three times a week was able to reduces oxidative damage and increases the efficiency of antioxidant system of mice

During the muscle contraction induced by exercises there is an increase in the reactive oxygen species production, causing oxidative stress in several organs, including liver and heart. The exercise may can increases antioxidant defenses and decrease oxidative stress in these organs. However, the number of the sessions a week necessary to improve the parameters of oxidative stress is not to well defined. The aim of the study was to investigate the frequency effects of exercise performed two and three times a week on changes in biomarkers of oxidative stress in the liver and heart. Were used 18 male mice (CF1), young (30 to 35g) and divided into groups (n=6/group): not trained (NT) trained twice a week (T2) and trained three times a week (T3). The animals were subjected to training for eight weeks. Forty-eight hours after the last session, the animals were killed. The liver and heart were removed and stored in - 70°C. Were analyzed the thiobarbituric acid reactive substances, protein carbonyls, content of total thiols, superoxide dismutase, catalase and glutathione peroxidase. Our findings showed that the group T3 reduced oxidative damage. There was increase in content of total thiols, superoxide dismutase and catalase in the T3 group when compared to NT. The glutathione peroxidase activity showed no significant difference between groups. This study demonstrated that only the frequency of training performed three times a week was able to reduces oxidative damage and increases the efficiency of antioxidant system of mice.