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Green synthesis of CoFe2O4/rGO nanocomposites utilizing plant leaf extracts as magnetically separable and reusable photocatalysts for organic toxic dye degradation
No full textDeveloping a sustainable and effective approach to separate photocatalytic nanoparticles from processed solutions is vital to support their reuse. Magnetic nanocomposites with superior catalytic efficiency and easy separability present a promising avenue for enhancing wastewater treatment processes. Here, we present the photocatalytic degradation of magnetically separable green synthesized cobalt ferrite/reduced graphene oxide (CoFe2O4/rGO) under ultra-violet irradiation. The CoFe2O4 nanoparticles were synthesized via a green approach using Moringa oleifera leaf extract as a reducing and capping agent, while rGO was prepared by reducing GO with Amaranthus viridis leaf extract. The crystallite size decreased with increasing rGO concentration. The morphological images illustrate that the particles were nearly spherical in shape and attached to the rGO sheet. The formation of the nanocomposite was confirmed by the detection of H-O-H, C-H, C＝C, Fe-O, and Co-O functional groups in the CoFe2O4/rGO nanocomposite. The UV–Vis spectrum of the nanocomposite exhibited a slight red shift at the band edge. Analysis of the magnetic properties revealed that the nanocomposite exhibited ferromagnetic behavior. The CoFe2O4/rGO 5:5 nanocomposite exhibited optimal efficiency in rhodamine B photodegradation, reaching a degradation rate of 78.6 % within 120 min, with 20 min intervals. The magnetic separability of the nanocomposites permitted recycling for up to three consecutive cycles. In light of these findings, the CoFe2O4/rGO nanocomposite demonstrates considerable promise as a standalone photocatalyst for the remediation of organic contaminants in the environment.journal articl
Enhanced magnetic hyperthermia properties of reduced graphene oxide-modified cobalt ferrite nanoparticles synthesized using green approach
No full textLocalized cancer therapy that can effectively target and kill cancer cells is a significant issue in the field of biomedicine. The modification of magnetic and fluorescent nanoparticles as heat mediators for magnetic hyperthermia is a novel and efficient strategy. This study investigated the potential of novel reduced graphene oxide-modified cobalt ferrite (CoFe2O4/rGO) nanoparticles (NPs) as a magnetic hyperthermia agent. NPs successfully fabricated using a green synthesis approach utilizing plant leaf extracts. X-ray diffraction spectra indicate the presence of cubic spinel phase CoFe2O4 and rGO phases NPs. The crystal size tends to decrease with increasing rGO concentration, ranging from 9.9 to 9.0 nm. Morphological images showed that the particles are nearly spherical and are well-attached to the rGO sheets, with the particle size decreasing from 14.8 to 13.3 nm after modification. Magnetic property analysis indicated that the NPs exhibit ferromagnetic behavior. Subsequently, for magnetic hyperthermia investigation, the NPs were dispersed in three different media—deionized water, ethylene glycol, and DMSO—to evaluate their heating characteristics based on specific absorption rate (SAR) in alternating magnetic fields at varying rGO concentrations. The SAR of CoFe2O4 was 178 and significantly increased to 736 mW/g for CoFe2O4/rGO. The findings suggest that green-synthesized CoFe2O4/rGO NPs are promising candidates for magnetic hyperthermia applications in cancer therapy. Their high saturation magnetization and favorable SAR values position them as effective candidates for magnetic hyperthermia, especially for cancer therapy and other biomedical applications.journal articl
Sleep stage, sleep fragmentation and heart rate variability during the initial 3-h sleep period in patients with obstructive sleep apnea syndrome
No full textTo investigate differences in polysomnography (PSG) parameters and heart rate variability (HRV) during the initial 3-h sleep period in patients with mild, moderate, and severe obstructive sleep apnea syndrome (OSA). According to the apnea–hypopnea index, patients were divided into 3 groups: mild, moderate, and severe (n = 23, 59, and 94, respectively). PSG was performed, and HRV (frequency domain analysis), sleep stage (S1, S2, S3, REM, and waking), and sleep fragmentation index (SFI) were measured during the initial 3-h sleep periods. The total S1 time was significantly longer in the severe group than in the mild and moderate groups (p < 0.001). The severe group had significantly shorter total S2 and S3 times than the mild (p = 0.014, p < 0.001) and moderate (p = 0.034, p = 0.029) groups did. The SFI was significantly greater in the severe group than in the mild and moderate groups (p < 0.001, p = 0.008). The high-frequency component (HF) of the HRV showed no significant differences except that it was significantly smaller during S3 in the moderate group than in the mild group (p = 0.026). Compared with those with mild/moderate status, patients with severe OSA have shallower sleep and a higher SFI, suggesting poorer sleep quality. Although HF during S3 was significantly smaller in the moderate group, it did not significantly differ between the mild and severe groups, suggesting that the parasympathetic nervous system might compensate for humoral and hypoxemic abnormalities in patients with severe OSA.journal articl
Experimental study on the effect of surface slip with varying zeta potential on particle migration in finite-size microchannels
No full textThe slip on the fluid–solid interfaces is a crucial factor to consider in microfluidic studies of particle motion. It can alter the zeta potential, thus influencing the separation or focusing behavior of particles. Consequently, the zeta potential serves as a useful tool to study how surface slip impacts particle motion. In this work, the zeta potential of polystyrene particles modified with various surface functional groups was measured in acidic, neutral, and basic environments. The zeta potential of the microchannel wall was also considered. The particle migration trajectory in low aspect ratio microchannels was experimentally investigated under varying flow rates and pH conditions. The radial migration probability distribution and focusing regions were roughly determined through quantitative analysis. Furthermore, the variations in the peak value of radial migration density vs particle zeta potential under different flow rates were summarized. The results demonstrated that the particle radial migration in the channel differs among three surface-modified particles under varying pH conditions. Slip could affect the velocity gradient around the particle surface, qualitatively explaining these differences. Additionally, the peak value of distribution density decreases with increasing particle zeta potential, while increasing flow rate makes this variation less obvious. This study provides experimental evidence for the slip effect on particle migration in microchannels and contributes to understanding the role of slip in particle motion at the microscale.journal articl
Protein kinase N promotes cardiac fibrosis in heart failure by fibroblast-to-myofibroblast conversion
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