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•Oxidative stress is one of the important mechanisms of MeHg-induced neurotoxicity.•Autophagy is one of the important processes of MeHg-induced neurotoxicity.•Oxidative stress plays a ...certain regulatory role on autophagy.•ROS and Nrf2 regulated mTOR-dependent/independent autophagy in MeHg neurotoxicity.
Methylmercury (MeHg) is a potential neurotoxin that is highly toxic to the human central nervous system. Although MeHg neurotoxicity has been widely studied, the mechanism of MeHg neurotoxicity has not yet been fully elucidated. Some research evidence suggests that oxidative stress and autophagy are important molecular mechanisms of MeHg-induced neurotoxicity. Researchers have widely accepted that oxidative stress regulates the autophagy pathway. The current study reviews the activation of Nuclear factor-erythroid-2-related factor (Nrf2)-related oxidative stress pathways and autophagy signaling pathways in the case of MeHg neurotoxicity. In addition, autophagy mainly plays a role in the neurotoxicity of MeHg through mTOR-dependent and mTOR-independent autophagy signaling pathways. Finally, the regulation of autophagy by reactive oxygen species (ROS) and Nrf2 in MeHg neurotoxicity was explored in this review, providing a new concept for the study of the neurotoxicity mechanism of MeHg.
Microsphere-assisted super-resolution imaging technology offers label-free, real-time dynamic imaging via white light, which has potential applications in living systems and the nanoscale detection ...of semiconductor chips. Scanning can aid in overcoming the limitations of the imaging area of a single microsphere superlens. However, the current scanning imaging method based on the microsphere superlens cannot achieve super-resolution optical imaging of complex curved surfaces. Unfortunately, most natural surfaces are composed of complex curved surfaces at the microscale. In this study, we developed a method to overcome this limitation through a microsphere superlens with a feedback capability. By maintaining a constant force between the microspheres and the sample, noninvasive super-resolution optical imaging of complex abiotic and biological surfaces was achieved, and the three-dimensional information on the sample was simultaneously obtained. The proposed method significantly expands the universality of scanning microsphere superlenses for samples and promotes their widespread use.
Vanadium nitride films exhibited excellent tribological properties due to the formation of Magnéli phases during the wear test, while the poor thermal stability, low hardness and high wear rate ...restricted it applied in cutting tool field. In this paper, aluminum was added into the vanadium nitride matrix in order to improve the thermal stability, mechanical and tribological properties. V-Al-N films with various Al content were deposited by reactive magnetron system and the effects of Al content on the micro-structure, oxidation resistance, mechanical and tribological properties of V-Al-N films were investigated. The results showed that V-Al-N films regardless of Al content exhibited a single face-centered cubic (fcc) structure. There was an increase in hardness when the content of Al was below 4.7 at.% with a corresponding decrease in room temperature friction coefficient (μ) and wear rate (WR). Rising Al content improved the oxidation resistance, while degraded the fracture toughness. The film at 4.7 at.% Al with highest hardness and lowest μ and WR was chosen to investigate its high temperature tribological properties. The rising temperature induced both the wear mechanism change and tribo-film vanadium oxides phase transition, and increased μ to 0.7 at 300 °C firstly and then dropped to 0.28 at 700 °C, while WR increased gradually. The film at 4.7 at.% Al was found to be optimized for cutting tool application.
•Vanadium aluminum nitride films were deposited by magnetron sputtering.•The maximum value of hardness was ∼24 GPa at 4.7 at.% Al.•Oxidation resistance temperature of the V-Al-N films increased from ∼420 °C at 0 at.% Al to ∼790 °C at 38.8 at.% Al.•The incorporation of Al into the VN film below 4.7 at.% improved the room tribological properties.•The tribological properties of the film at 4.7 at.% Al were investigated.
In this letter, based on the plasmonic split-ring dimer metasurface (SRDM), an optical filter with dual operating bands, high absorption, narrow linewidth and simple design is proposed and ...experimentally demonstrated. Due to the configuration of periodic array and the excited two kinds of strong mode coupling (i.e., double-dipole, and double-quadrupole coupling) within the designed split-ring dimer, dual narrow filtering channels with enhanced light absorption are successfully generated and the filtering wavelengths can be flexibly tuned by changing geometrical parameters, angle of incidence and cladding material. The simulation results show that this optical filter has two resonant central wavelengths at 733 nm and 918 nm with the ultrahigh absorption efficiency of 1 at both positions. The experimental results verify the high energy-filtering effect of 0.78 at the first resonant wavelength of ~769 nm and the responses to different incident angles. This remarkable device performance underscores the potential of our proposed device for a myriad of practical applications at the nanoscale, including signal processing and imaging.
The insight into the composition of iron corrosion products is critical for corrosion studies. A novel and non-destructive method is proposed in this paper to quantitatively analyse the binary iron ...oxides mixtures based on the terahertz time-domain spectroscopy combined with the effective medium theory. The utility of this method is exemplified by analysing the THz refractive index for a set of samples, including hematite, magnetite, and their mixtures at several volume ratios. The effective medium theory is applied to the raw data of single-component samples to remove the dielectric influence of dilution polymer matrix and trapped air voids. The refractive index of hematite and magnetite is determined to be 4.01 ± 0.04 (1.00%) and 5.6 ± 0.2 (3.6%). The measured refractive index of two iron oxides is further adopted to construct an effective medium model for the binary mixture. The analytical model can predict the volume ratios of two iron oxides within the mixture. Comparison between the theoretical predictions and experimental measurements reveals a relative difference of less than 10.0%.
Methylmercury (MeHg) is one of the ubiquitous environmental toxicant that leads to long-lasting neurological deficits in animals and humans. However, the mechanisms of MeHg-induced neuronal cell ...death are incompletely understood. Treatment of neuronal cells with MeHg (0-2 μM) for 0.5-12 h, or pretreated with LA (12.5-100 μM) for 0.5-6 h resulted in toxic effects of primary cultured neurons concentration- and time-dependently. For further experiments, 12.5, 25, and 50 μM of LA pretreatment for 3 h followed by 1 μM MeHg for 6 h were performed for the examination of the responses of neurons. Exposure of MeHg resulted in damages of neurons, which were shown by a loss of cell viability, and supported by high levels of lactate dehydrogenase (LDH) release, apoptosis, and morphological changes. In addition, neurons were sensitive to MeHg-mediated oxidative stress, a finding that is consistent with ROS over-production, leading to decrease Ca
2+
-ATPase activity and increase intracellular free calcium. Moreover, expressions of NMDA receptor subunits in neurons were down-regulated after MeHg exposure, and expression of NR2A mRNA and protein were much more sensitive to MeHg than those of NR1 and NR2B. On the contrary, pretreatment with LA presented a concentration-dependent prevention against MeHg-mediated cytotoxic effects of neurons. In conclusion, present results showed that oxidative stress and intracellular Ca
2+
dyshomeostasis resulting from MeHg exposure contributed to neuronal injury. LA could attenuate MeHg-induced neuronal toxicity via its antioxidant properties in primary cultured neurons.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Nanomanipulation provides high operating accuracy and has been successfully applied in many fields such as nanoparticle assembly, nanowire alignment, and semiconductor device manufacturing. However, ...because of the limits of optical diffraction, the use of nanomanipulation is challenged by a lack of visual feedback at the nanoscale, and thus, its efficiency is difficult to be improved. In this study, we developed a novel method of microlens-enhanced nanomanipulation capable of real-time super-resolution imaging. Nanomanipulation was performed using the atomic force microscopy (AFM) mechanism by coupling a microlens to an AFM probe, and optical imaging with a minimum characteristic size of 80 nm is realized by combining the microlens with the optical imaging system. Under the conditions of fluorescent illumination and white light illumination, nanomanipulations were achieved under real-time visual guidance for fluorescent nanoparticles with a diameter of 100 nm and silver nanowires with a diameter of 80 nm, respectively. This method enables the possibility of in situ observation and manipulation, which can potentially be used for biological samples.
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•The mesoporous zeolite confined Pt-CeO2 strategy enhances catalyst durability.•The Pt-CeO2@meso-S1 catalyst exhibits excellent toluene degradation activity.•The confinement effect ...inhibits Pt sintering at high temperature environments.•The Pt-CeO2 interface promotes the formation of oxygen vacancies.
The efficient degradation of volatile organic compounds (VOCs) at low temperatures is urgently needed due to the serious environmental and health hazards they pose. While precious metal-based catalysts offer excellent performance, their application is limited by high-temperature sintering and aggregation. Therefore, inhibiting the migration and aggregation of precious metals during the reaction process can effectively improve their utilization and alleviate catalyst deactivation. In this study, a novel encapsulated catalyst (Pt-CeO@meso-S1) containing Pt-CeO2 interfaces was constructed using mesoporous-rich zeolite as a shell layer and applied to the catalytic oxidation of toluene. The introduction of CeO2 constructed a Pt-CeO2 active interface that promoted the low-temperature degradation of toluene, achieving complete oxidation of toluene at 160 ℃. The crystalline phase transition strategy enhanced the specific surface area, improving the dispersion of platinum and facilitating the construction of the Pt-CeO2 interface. The zeolite shell and mesoporous pores effectively confined/stabilized the Pt-CeO2 active components and inhibited platinum sintering, resulting in outstanding water resistance and high-temperature stability. DFT calculations demonstrated that the presence of the Pt-CeO2 active interfaces reduced oxygen vacancy formation energy and facilitated gas-phase oxygen activation. DFT calculations demonstrated that the presence of the Pt-CeO2 active interfaces reduces the oxygen vacancy formation energy and boosts the activation of gas-phase oxygen. The Mars-van-Krevelen (MvK) mechanism governing toluene degradation over Pt-CeO2@meso-S1 was revealed by in situ DRIFTS. This work provides a promising candidate for industrial high-performance catalytic removal of VOCs at low temperatures.
Abstract Background This study aimed to investigate the alterations in structural integrity of superior longitudinal fasciculus subcomponents with increasing white matter hyperintensity severity as ...well as the relationship to cognitive performance in cerebral small vessel disease. Methods 110 cerebral small vessel disease study participants with white matter hyperintensities were recruited. According to Fazekas grade scale, white matter hyperintensities of each subject were graded. All subjects were divided into two groups. The probabilistic fiber tracking method was used for analyzing microstructure characteristics of superior longitudinal fasciculus subcomponents. Results Probabilistic fiber tracking results showed that mean diffusion, radial diffusion, and axial diffusion values of the left arcuate fasciculus as well as the mean diffusion value of the right arcuate fasciculus and left superior longitudinal fasciculus III in high white matter hyperintensities rating group were significantly higher than those in low white matter hyperintensities rating group ( p < 0.05). The mean diffusion value of the left superior longitudinal fasciculus III was negatively related to the Montreal Cognitive Assessment score of study participants ( p < 0.05). Conclusions The structural integrity injury of bilateral arcuate fasciculus and left superior longitudinal fasciculus III is more severe with the aggravation of white matter hyperintensities. The structural integrity injury of the left superior longitudinal fasciculus III correlates to cognitive impairment in cerebral small vessel disease.
•A electrochemical biosensor based on double molecular recognition for selective detecting dopamine was developed.•This new biosensor was applied to monitor dopamine levels in brain ...microdialysate.•The volume of the microdialysate was as low as 7 μL, thus leading to off-line dopamine monitoring at 4 min interval.•Dopamine dynamics evoked by high K+ and nomifensine were studied.
Dopamine (DA) monitoring with high selectivity and sensitivity in the cerebrally extracellular fluid is of high value for evaluating the role of DA in the physiological and pathological processes. Especially because neurotransmission involved in rapid events, lowering the detection interval in order to gain more insight into DA dynamics inserts great challenge into the DA analytical method. In this work, a facile electrochemical biosensor for sensing DA with high sensitivity was developed here. Double molecular recognition based on boronic acid-diol and N-hydroxysuccinimide ester-amine endows the new biosensor favourable selectivity for cerebral DA detection. More importantly, microdialysate volume as low as 7 μL was requisite for the DA analysis without suffering from a sensitivity loss, thus monitoring DA concentration in brain microdialysate at 4 min interval was successfully achieved. Subsequently, the present biosensor was successfully employed for monitoring of cerebral DA transients evoked by high K+ and nomifensine.
