Long-lived luminescence in the blue region was found to occur in deionized water saturated with atmospheric gases following mechanical shaking. Luminescence intensity decreased exponentially after the cessation of stress. During vigorous mechanical shaking, we observed gas bubbles in solution, and the liquid–gas interface area increased noticeably. At the same time, the concentration of molecular oxygen decreased, which could not be attributed to the water warming up with exposure to mechanical stress. However, deaerated water rapidly became saturated with gases following mechanical stress. The recommendation that cell culture media should be mixed after they are removed from the fridge in order to allow saturation with oxygen is probably misleading. It was shown that gases existed in water both in the form of individual molecules and nanobubbles. Mechanical stress did not influence the number or size of nanobubbles. While gas nanobubbles were absent in freshly prepared deaerated water, they appeared following exposure to mechanical stress. In addition, in mechanically treated gas-saturated water, there was seemingly an equilibrium shift towards the decomposition of carbonic acid to water and carbon dioxide. At the same time, the pH of water tended to increase immediately after mechanical stress. It was demonstrated that reactive oxygen species (ROS) form in gas-saturated water under mechanical stress (30 Hz, amplitude of 5 mm). The relative generation rate of hydrogen peroxide and of the hydroxyl radical was 1 nM/min and 0.5 nM/min, respectively. It was found that with an increase in the frequency of mechanical action (f), the rate of ROS generation increased in proportion to f ². The major pathways for hydrogen peroxide generation are probably associated with the formation of singlet oxygen and its further reduction, and the alternative pathway is the formation of hydrogen peroxide as a result of hydroxyl radical recombination.

An experiment has been performed, where water enriched in hydrogen peroxide was subjected to multiply dilution under mechanical action. It is established that, when the number of dilutions reaches a...

The synthesis of silicon nanoparticles in the reaction of the silane pyrolysis is presented. The reaction of the silane decomposition is performed in a flow reactor in the presence of the cw CO₂-laser irradiation. As-prepared Si nanoparticles are studied with the aid of transmission electron microscope, fiber spectrometer, and FTIR spectrometer. Spherical Si nanoparticles with a diameter of about 15 nm are produced. The luminescence of the as-prepared nanoparticles is virtually absent. The nanoparticles are etched in acid vapor and are oxidized to increase the luminescence quantum yield. After the chemical treatment, the mean size of the crystalline core of nanoparticles decreases to 5 nm and the luminescence spectrum exhibits the band peaked at 730 nm.

The physicochemical properties of NaCl aqueous solutions in a wide range of concentrations were studied. We determined that constant magnetic fields with an induction of up to 7 T had a significant effect on the physicochemical properties of these solutions. First, we detected a decrease in pH that was dependent on the magnetic field strength both in water and in NaCl solutions. This effect was not associated with the presence of sodium cations or chlorine anions in water. Secondly, with an increase in magnetic field induction the redox potential of aqueous solutions also increased. Magnetic fields did not cause any changes in the concentration of dissolved molecular oxygen in deionized water. In this case, in aqueous solutions of NaCl under the action of a magnetic field, a concentration-dependent tendency to a decrease in the concentration of dissolved molecular oxygen is observed. Third, it was shown that under the action of a magnetic field on a NaCl solution, the rate of hydrogen peroxide generation increased with increasing NaCl concentration. Fourth, the essential role of the primary state of aqueous solutions in relation to the gas composition and gas equilibrium under magnetic influence was established. The work also evaluated the contribution of flow-mixing during sample preparation on the physicochemical properties of the solutions.

Water is the basis of life. Any factors acting on water will also affect the functioning of living organisms, including humans. Mechanical effects are as ubiquitous as temperature or magnetic fields. Numerous works have been devoted to the action of mechanical impacts on living systems, aqueous solutions, and water. However, no unified theory that would allow predicting the consequences of mechanical effects on living organisms based on their characteristics. In this review, we have attempted to systematize the available quantitative data on the effects of mechanical impacts on living organisms, cells, aqueous solutions, and purified water. In addition, in this review, we provide a basic overview of the variety of mechanical effects and the mechanisms of their realization. The responses of living systems and aqueous solutions depend quantitatively on different sets of characteristics of the vibration action. The magnitude of responses of living systems (cells and organisms) to mechanical action correlates with frequency, acceleration, and force. Mechanical action changes the characteristics of water and aqueous solutions as a function of frequency, acceleration, and duration. The data obtained may find application in a wide range of fields: from analytical chemistry and pharmacology to environmental protection.

Optical methods (spectroscopy, spectrofluorometry, dynamic light scattering, and refractometry) were used to study the change in the state of hen egg-white lysozyme (HEWL), protein molecules, and gold nanoparticles (AuNPs) in aqueous colloids with changes in pH, and the interaction of protein molecules with nanoparticles was also studied. It was shown that changing pH may be the easiest way to control the protein corona on gold nanoparticles. In a colloid of nanoparticles, both in the presence and absence of protein, aggregation–deaggregation, and in a protein colloid, monomerization–dimerization–aggregation are the main processes when pH is changed. A specific point at pH 7.5, where a transition of the colloidal system from one state to another is observed, has been found using all the optical methods mentioned. It has been shown that gold nanoparticles can stabilize HEWL protein molecules at alkaline pH while maintaining enzymatic activity, which can be used in practice. The data obtained in this manuscript allow for the state of HEWL colloids and gold nanoparticles to be monitored using one or two simple and accessible optical methods.