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Microwave-Induced Structural Changes in Bacteriorhodopsin: Studies by Optical and Fourier Transform Infrared Difference Spectroscopy
摘要： Using optical and Fourier transform infrared (FTIR) difference spectroscopy, microwave radiation was found to affect the bacteriorhodopsin (BR) structure in films at a 30% relative humidity. This study is the first to demonstrate that a transition from the dark-adapted basal state BR560 to a state similar to the light-adapted state BR568, which is a mixture of BR568 and other isomeric forms, occurs in the absence of external photoexcitation on exposure to microwave radiation with a frequency range of 8 ≤ f ≤ 18 GHz and an intensity lower than 10 mW/cm2. The initial response of dark-adapted BR to microwave radiation included collective motion of a large portion of protein atoms, producing relatively strong signals in the regions 3700–3300, 2400–2300, and 800–600 cm–1 of the FTIR difference spectrum. Relatively weak amplitude responses were detected in the frequency range characteristics of the retinal chromophore and amide bands (Amide I and Amide II). The effects reflected changes in the retinal chromophore structure and local changes in the chromophore microenvironment.
关键词： FTIR difference spectroscopy,microwave radiation,bacteriorhodopsin,dark–light adaptation,biological effect,optical spectroscopy
更新于2025-09-19 17:15:36
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Semiconductor Plasma Antennas Formed by Laser Radiation
摘要： Efficiency of the transmission of high-frequency signals by semiconductor plasma antennas based on Ge and Si single crystals with surface nonequilibrium electron-hole plasma generated by laser diode radiation has been experimentally studied. Dependences of the amplitude of a radiated 6- to 7.5-GHz microwave signal on the laser power and size of the laser-irradiated region on the semiconductor transmitting dipole antenna are determined. It is shown that a more than tenfold increase can be achieved in the efficiency of useful signal transmission by the plasma antenna formed in Ge crystals.
关键词： laser radiation,plasma antenna,silicon,germanium,microwave radiation,semiconductor,electron-hole plasma
更新于2025-09-16 10:30:52
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[IEEE 2018 EMF-Med 1st World Conference on Biomedical Applications of Electromagnetic Fields (EMF-Med) - Split, Croatia (2018.9.10-2018.9.13)] 2018 EMF-Med 1st World Conference on Biomedical Applications of Electromagnetic Fields (EMF-Med) - Brain stimulation by modulated microwave radiation: a feasibility study
摘要： The aim of this study was to evaluate the feasibility of stimulating the brain oscillations at predetermined frequencies using low level modulated (40 Hz) microwave radiation (450 Hz). The field power density was 0.16 mW/cm2. The resting EEG of 14 subjects was recorded and EEG power at fixed frequencies was analyzed. A relative change in the EEG power during 10 cycles with and without radiation was used as a quantitative measure. Microwave radiation caused statistically significant increase in the average EEG power at expected 10, 20 and 30 Hz frequency bands. The results indicate that low-level modulated microwave radiation is able to stimulate brain oscillations at selected frequencies.
关键词： EEG,modulation,excitation,microwave radiation
更新于2025-09-10 09:29:36
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Second Harmonic Generation under the Influence of the Earth’s Gravitational Field
摘要： The influence of the Earth’s gravitational field on a weakly relativistic electron involved in the process of generation of microwave radiation is evaluated. It is shown that such exposure leads to the generation of a second harmonic.
关键词： drift tube,electron,microwave radiation,gravity
更新于2025-09-10 09:29:36
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Carbohydrate Functionalization of Few-Layer Graphene through Microwave-Assisted Reaction of Perfluorophenyl Azide
摘要： The excellent physical and chemical properties of graphene make it an attractive nanomaterial and a component in high-performance nanocomposite materials. To prepare graphene-based nanocomposite materials, the chemical functionalization is often necessary. Water-soluble ligands such as carbohydrates not only make the functionalized graphene compatible with aqueous media, but also introduce bio-recognition which is important for graphene to be used in biotechnology. In this study, we report the derivatization of few-layer graphene (FLG) with carbohydrates through microwave-assisted reaction of perfluorophenyl azide (PFPA). FLG was first treated with PFPA under microwave radiation. Subsequent conjugation with glycosyl amine gave carbohydrate-presenting FLG. Thermogravimetric analysis showed that microwave radiation gave a higher degree of functionalization compared to conventional heating, with higher weight losses for both PFPA and Man ligands. The carbohydrates (mannose and galactose) retained their bioactivity, as demonstrated by the lectin binding assays. Higher degree of binding towards lectins was obtained for the carbohydrate-functionalized FLG prepared by microwave radiation than the conventional heating.
关键词： microwave radiation,perfluorophenyl azide,graphene,carbohydrate,lectin
更新于2025-09-04 15:30:14
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An Experimental Cell for a Radio Light Receiver
摘要： The problem of creating a receiver for incoherent microwave radiation from sources realized on the basis of ultra-wideband oscillators of chaotic oscillations and objects and surfaces “illuminated” by these sources has been considered. The structure of the device is proposed, the experimental sample is described, and its ability to register sources of incoherent microwave radiation with an integrated output power of ~2 mW at a distance of more than 100 m is shown.
关键词： incoherent microwave radiation,chaotic oscillations,ultra-wideband oscillators,radio light receiver
更新于2025-09-04 15:30:14