RESUMO
Biocatalytic membranes have great potential in various industrial sectors, with the immobilization of enzymes being a crucial stage. Immobilizing enzymes through covalent bonds is a complex and time-consuming process for large-scale applications. Polydopamine (PDA) offers a more sustainable and eco-friendly alternative for enzyme immobilization. Therefore, surface modification with polydopamine as mussel-inspired antifouling coatings has increased resistance to fouling. In this study, α-amylase enzyme was covalently bound to a bioactive PDA-coated polyethersulfone (PES) membrane surface using cyanuric chloride as a linker. The optimal activity of α-amylase enzyme immobilized on PES/PDA membrane was obtained at temperature and pH of 55°C and 6.5, respectively. The immobilized enzyme can be reused up to five reaction cycles with 55â¯% retention of initial activity. Besides, it maintained 60â¯% of its activity after being stored for five weeks at 4°C. Additionally, the immobilized enzyme demonstrated increased Michaelis constant and maximum velocity values during starch hydrolysis. The results of the biofouling experiment of various membranes in a dead-end cell demonstrated that the PES membrane's water flux increased from 6722.7 Lmh to 7560.2 Lmh after PDA modification. Although α-amylase immobilization reduced the flux to 7458.5 Lmh due to enhanced hydrophilicity, compared to unmodified membrane. The findings of this study demonstrated that the membrane produced through co-deposition exhibited superior hydrophilicity, enhanced coating stability, and strong antifouling properties, positioning it as a promising candidate for industrial applications.
Assuntos
Estabilidade Enzimática , Enzimas Imobilizadas , Indóis , Membranas Artificiais , Polímeros , Sulfonas , alfa-Amilases , Indóis/química , Polímeros/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Sulfonas/química , alfa-Amilases/metabolismo , alfa-Amilases/química , Concentração de Íons de Hidrogênio , Incrustação Biológica/prevenção & controle , Temperatura , Hidrólise , TriazinasRESUMO
Silica nanoparticles (SiO2 NPs) have been widely used in the medical and food sciences. However, their toxic effects against bio-macromolecules and cells are not well understood. The present study was aimed to investigate the adverse effects of fabricated SiO2 NPs on the human hemoglobin (Hb) by FTIR, CD, fluorescence, and UV-vis spectroscopic techniques. Moreover, the toxic effects of SiO2 NPs on the human lymphocyte cell was assessed by trypan blue, reactivate oxygen species (ROS), and apoptosis assays. It was shown that synthesized SiO2 NPs have an amorphous structure with dominant size of around 20-30â¯nm. FTIR results showed that SiO2 NPs bind to Hb and induce significant structural changes on the native structure of Hb. Near CD spectroscopy depicted that SiO2 NPs induced tertiary structural changes and heme displacement. Fluorescence spectroscopy demonstrated the production of heme degradation species in the Hb solution after interaction with SiO2 NPs. UV-vis spectroscopy experiment indicated the release of iron form Hb after interaction with SiO2 NPs in a concentration dependent manner. Live-dead staining, ROS detection and flow cytometry analysis revealed that human lymphocyte was sensitive towards the toxicity of SiO2 NPs in a ROS-mediated apoptosis mechanism. In conclusion, SiO2 NPs exhibited concentration-dependent toxicity.
Assuntos
Heme/metabolismo , Hemoglobinas/metabolismo , Ferro/metabolismo , Linfócitos/metabolismo , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Dióxido de Silício , Humanos , Linfócitos/citologia , Dióxido de Silício/química , Dióxido de Silício/farmacologiaRESUMO
BACKGROUND: Multiple sclerosis (MS), a chronic disease of the central nervous system (CNS), causing progressive nerve damage, has disabling symptoms, and undermines self-efficacy beliefs. Due to the importance of self-efficacy modified in adaptation and coping with stress, this study was conducted with the aim to investigate the effect of emotional intelligence training on self-efficacy in women with MS. MATERIALS AND METHODS: This randomized clinical trial was conducted on 70 women referring to the Multiple Sclerosis Clinic of Kashani Hospital, Isfahan, Iran. The participants were randomly assigned to two groups through minimization method. In the experimental group, emotional intelligence training was performed within 8 weeks, once a week for 90 minutes, in groups of 8-9 individuals. Data were collected using the Multiple Sclerosis Self-efficacy Scale (MSSS) before, immediately after, and 3 months after the intervention in both groups. Data were analyzed using independent t-test and repeated measures ANOVA in SPSS. RESULTS: The results of independent t-test showed no significant difference between the groups in terms of mean self-efficacy scores before the intervention (p > 0.05). However, there was a significant difference between the groups in this regard immediately after and 3 months after the intervention (p < 0.05). Repeated measures ANOVA showed a significant difference in the mean score of self-efficacy and its components between the groups at different times (p < 0.05). CONCLUSIONS: It seems that emotional intelligence training is effective on the improvement of self-efficacy of women with MS. Hence, this method can be recommended as an effective and affordable technique.
RESUMO
In an attempt to determine the types of non-polio enteroviruses (NPEVs) in acute flaccid paralysis (AFP) cases in Iran, we detected enterovirus 71 (EV71) in an AFP case with residual paralysis for the first time. Cell culture detected no enteroviruses, while RT-PCR and subsequent sequencing revealed that the specimen was positive for EV71. EV71 is the causative agent of a variety of diseases from hand, foot and mouth disease to severe neurological complications and is now considered as an important cause of childhood acute flaccid paralysis.