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State-of-the-Art of Studies of the Effect of Terahertz Radiation on Living Biological Systems
摘要： The appearance of modern sources and detectors of terahertz radiation (1011–1013 Hz) stimulated the rapid development of practical applications for radiation in this frequency range. Therefore, the question of the safety of terahertz radiation for living objects was sharply raised. In this review, we present an analysis of research on this issue published from 2010 to the present. A brief description of the most significant works performed before 2010 is given. Particular attention is paid to the sources of terahertz radiation used in the studies and the results of experimental work on the study of possible bioeffects when such radiation is applied to both individual cell lines and microorganisms and animals generally.
关键词： cell lines,biological systems,bioeffects,safety,animals,terahertz radiation,microorganisms
更新于2025-09-23 15:21:01
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Optimization of rDNA degradation in recombinant Hepatitis B vaccine production plant wastewater using visible light excited Ag-doped TiO2 nanophotocatalyst
摘要： As widespread distribution of recombinant DNA of genetically modified microorganisms is a threat to the environment, the aim of this research is to investigate the efficiency of photocatalytic degradation of recombinant DNA under visible light. Using response surface methodology, a comprehensive evaluation of Ag doped-TiO2 photocatalytic degradation of recombinant DNA in Hepatitis B surface antigen production plant wastewater was performed. Photocatalytic synthesis parameters including dopant content, calcination temperature, and heating rate were investigated to model and optimize the recombinant DNA degradation efficiency. The Ag doped-TiO2 nanoparticles synthesis validation was accomplished by XRD, UV-Vis diffuse reflectance spectra, FESEM and energy-dispersive X-ray spectroscopy. A quadratic polynomial equation, developed by response surface methodology, with the correlation coefficient (R2) of 0.969 ensured the good fitness of the predicted data with the experimental results. The sensitivity analysis of model indicates that the square of silver content and calcination temperature have the greatest effect on the response, while the heating rate is the least important parameter. Furthermore, the optimum conditions of Ag content of 2.1%, calcination temperature of 485 ?C, and heating rate of 8 ?C/min resulted in 80.7% rDNA degradation experimentally.
关键词： photocatalytic degradation,genetically modified microorganisms,Ag-doped TiO2,Pichia Pastoris,recombinant DNA,Real-time PCR
更新于2025-09-23 15:19:57
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Physical processes affecting the survival of microbiological systems in laser printing of gel droplets
摘要： We consider laser printing of gel microdroplets – a promising method for microbiology, biotechnology and medicine. In the printing process, small volumes of gel containing living microorganisms are transferred as a result of cavitation caused by the absorption of a short laser pulse in a metal film. However, in such a transfer, certain physical factors arise that can lead to damage and death of biological material. These factors include elevated temperature and pressure, high radiation intensity and some others. Experimental estimates of these parameters are conducted, based on measurements of the acoustic response of laser printing, electron microscopy of the affected areas and the results of high-speed imaging of the transfer process. It is shown that these factors are not a significant limitation for the technology being developed. Laser printing is performed by exposing a metal film to laser pulses with an energy of 5 – 30 mJ and a duration of 8 – 14 ns, the laser beam diameter being 30 mm.
关键词： nanoparticles,microorganisms,laser pulsed action,acoustic signal
更新于2025-09-16 10:30:52
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Inativa??o de microrganismos indicadores de contamina??o fecal por radia??o ultravioleta e avalia??o dos fen?menos de fotorreativa??o e recupera??o no escuro
摘要： This research aimed to evaluate the performance of ultraviolet radiation (UV) for disinfecting effluents from a municipal wastewater treatment plant, in laboratory bench scale and batch operation. The interference of the operational parameters of exposure time (s) to the radiation and the level of liquid blade (cm) of the effluent in the UV reactor were analyzed. The efficiency of the disinfection process was checked using the indicators microorganisms Clostridium perfringens (C. perfringens), coliphages, Escherichia coli (E. coli) and total coliforms (TC). After disinfection, some tests were carried out to evaluate the phenomena of microbiological recovery: photoreactivation and dark repair, for E. coli and TC. The results indicate effective inactivation of indicator microorganisms by UV radiation during the time of exposure, which was statistically proved by repeated measures ANOVA. C. perfringens was the microorganism that showed the highest resistance against UV inactivation. In microbiological recovery tests, both mechanisms were considered insignificant, which was statistically proven by the Student (t test — parametric data) and the Wilcoxon (nonparametric data) tests. In all analyses, the level of significance was 5%.
关键词： disinfection,indicators microorganisms,ultraviolet radiation,mechanisms of microbiological recovery
更新于2025-09-04 15:30:14