Fabrication of Asymmetric Supercapacitors (AC@GQDs//AC) with High Electrochemical Performance Utilizing Activated Carbon and Graphene Quantum Dots.

Sugar cane bagasse stands as a prevalent and abundant form of solid agricultural waste, making it a prime candidate for innovative utilization. Harnessing its potential, we embarked on a groundbreaking endeavor to evaluate the sustainability of a molasses-based hydrothermal process to produce graphene quantum dots (GQDs). This pioneering initiative promises remarkable environmental benefits and holds immense economic potential. Embedding crystalline GQDs in activated carbon (AC) boost electrochemical efficiency by enhancing charge-transfer and ion migration kinetics. Optical, structural, and morphological evaluations were used to confirm the formation of GQDs. Transmission electron microscopy (TEM) investigation showed the size, shape, and fact that GQDs were monodispersed, and X-ray diffraction and Fourier transform infrared determined the structure of GQDs. The electrodes with negative (AC) and positive (AC@GQDs) polarity demonstrate a considerable specific capacitance of 220 and 265 F g-1, respectively, when measured at 0.5 A g-1. Additionally, these electrodes exhibit high-rate capabilities of 165 and 230 F g-1 when measured at 5 A g-1, as determined by galvanostatic charge-discharge techniques. The supercapacitor device comprising asymmetric AC//AC@GQDs exhibits a specific capacitance of 118 F g-1. Furthermore, the asymmetric device exhibits exceptional cycling behavior, with an impressive 92% capacitance retention even after undergoing 10,000 cycles. This remarkable performance underscores the immense potential of both the negative and positive electrodes for real-world supercapacitor applications. Such findings pave the way for promising advancements in the field and offer exciting prospects for practical utilization.

Apoptotic and DNA-damaging effects of yttria-stabilized zirconia nanoparticles on human skin epithelial cells.

BACKGROUND: Yttria-stabilized zirconia (Y2O3/ZrO2) nanoparticles are one of the important nanoparticles extensively used in manufacturing of plastics, textiles, catalyst, etc. Still, the cytotoxic and apoptotic effects of yttria-stabilized zirconia nanoparticles have not been well identified on human skin keratinocyte (HaCaT) cells. Therefore, in this study, we have designed to examine the cytotoxic potential of yttria-stabilized zirconia nanoparticles in HaCaT cells. METHODS: Prior to treatment, the yttria-stabilized zirconia nanoparticles were characterized by using different advanced instruments viz. dynamic light scattering (DLS), scanning electron microscope (SEM) and transmission electron microscope (TEM). Cell viability of HaCaT cells was measured by using MTS and NRU assays and viability of cells was reduced in a dose- and time-dependent manner. RESULTS: Reduction in the viability of cells was correlated with the rise of reactive oxygen species generation, increased caspase-3, mitochondria membrane potential and evidence of DNA strand breakage. These were consistent with the possibility that mitochondria damage can play a significant role in the cytotoxic response. Moreover, the activity of oxidative enzymes such as lipid peroxide (LPO) was increased and glutathione was reduced in HaCaT cells exposed with yttria-stabilized zirconia nanoparticles. It is also important to indicate that HaCaT cells appear to be more susceptible to yttria-stabilized zirconia nanoparticles exposure after 24 hrs. CONCLUSION: This result provides a dose- and time-dependent apoptosis and genotoxicity of yttria-stabilized zirconia nanoparticles in HaCaT cells.