The possibility of using columns with nitrile, diol, and amino sorbents to separate butylhydroxyanisole isomers by hydrophilic interaction liquid chromatography was studied. Columns containing nitrile and diol sorbents did not separate butylhydroxyanisole isomers using either hydrophilic interaction liquid chromatography or reverse phase chromatography. Separation of butylhydroxyanisole isomers by reverse phase chromatography was only obtained on a Diasphere 110 C10CN 250 × 4.6 mm, 5 μm column using acetonitrile:water (50:50) or methanol:water (65:35) as the mobile phase. These isomers could only be separated by hydrophilic interaction chromatography on columns containing an amino sorbent when the acetonitrile level in the mobile phase was greater than 97%. Columns containing amino sorbents had greater selectivity for butylhydroxyanisole isomers than columns containing C18 sorbents in reverse phase chromatography. Better isomer separation was obtained on Zorbax NH2150 × 4.6 mm, 5 μm columns with a mobile phase acetonitrile content of 99 – 99.5%.

This study presents the results of calculations of dosimetry parameters for a 169Yb model brachytherapy source. The calculations were performed by a program code that was written by the authors using the GEANT4.9 software package for Monte Carlo simulation. According to the AAPM TG-43 formalism (the American Association of Physicists in Medicine, Task Group No. 43), the following parameters were deter- mined: the dose-rate constant, radial dose functions, and anisotropy function. To verify the program code, the calculation of the dosimetry parameters of the widespread BEBIG Co0.A86 and BEBIG Ir2.A85-2 sources was carried out. An acceptable fit with the data of other authors was obtained. The data we obtained using the developed and verified program code could be used in dosimetry planning systems.

Using Monte Carlo simulation, this paper explores the passing of gamma radiation through biological thin layers. In radiobiological experiments, this method of investigation simulates the conditions for determining the relative biological effectiveness (RBE). X-ray spectra from X-ray tubes, which are often used in such experiments, are simulated in this paper. The RBE is determined as the ratio of absorption doses, when the number of ionization events is equal for gamma and X-ray radiation. The results of the estimates are represented for the modeling of X-ray spectra in the case of irradiation of biological layers of different thicknesses.

Passage of 1–400 keV photons through thin layers (0.001–1.0 mm) of biological matter was simulated. Monte Carlo simulation was performed using the GEANT4.9 software package. The energy dependences of the absorbed dose and number of ionizing events and the number of ionizing events per unit absorbed dose were obtained. It was shown that the dependences in many respects are determined by the thickness of layers. Assuming that equal numbers of ionizing events in the layer cause equal biological effects, energy dependences of relative biological effectiveness of photons in the energy range studied have been estimated.

The energy dependence of a thimble-chamber calibration coefficient is modeled in this work according to beam quality using the Monte Carlo method. The maximums of the deviations were observed within the range of photon energies that correspond to the giant dipole resonance for light elements. The deviations may reach 10% at photon energies of up to 25 MeV.

The paper presents some findings of the investigation of finish turning of KhVG hardened steel (60–62 HRC) using a cutting tool with an insert made of a cubic boron nitride based composite (cBN-Si3N4 system). The influence of machining process variables on the cutting force components, vibrations, and machined surface roughness is clarified. The authors propose some practical recommendations of how to choose machining modes and conditions.

The possibility of using domestic chromatographic columns for organic nitrate derivative drug analysis was studied. A considerable advantage of these columns is in their cost, which is rather low in comparison with the imported analogues. The research results proved that columns with sorbents of C18 type (Dyaspher 110S18, Dyasorb 13016T, Dyaspher 110S16) as well as columns with nitrite groups (Dyaspher 110nitril, Dyaspher 110C10CN) can be successfully used for the above mentioned purposes.

This report presents results obtained from studies of the use of chromatographic columns of Russian origin, which are significantly cheaper than imported analogs, for analysis of medicinal agents from the organic nitrates group. The results showed that columns containing type C18 sorbent (Diasfer 110 C18, Diasorb 130 16T, Diasfer 110 C16), like columns bearing nitrile groups (Diasfer 110 nitrile, Diasfer 110 C10CN), can be used successfully for these purposes.

The results of simulation of irradiation of tissue-equivalent targets by 20-MeV electron beams in the presence of solenoid magnetic fields are discussed. These results are compared with the corresponding data obtained without magnetic fields. The data obtained can be used to solve beam therapy problems.