Alexey N. Zhigach

Image analysis is widely applied in plant science for phenotyping and monitoring botanic and agricultural species. Although a lot of software is available, tools integrating image analysis and statistical assessment of seedling growth in large groups of plants are limited or absent, and do not cover the needs of researchers. In this study, we developed Morley, a free, open-source graphical user interface written in Python. Morley automates the following workflow: (1) group-wise analysis of a few thousand seedlings from multiple images; (2) recognition of seeds, shoots, and roots in seedling images; (3) calculation of shoot and root lengths and surface area; (4) evaluation of statistically significant differences between plant groups; (5) calculation of germination rates; and (6) visualization and interpretation. Morley is designed for laboratory studies of biotic effects on seedling growth, when the molecular mechanisms underlying the morphometric changes are analyzed. The performance was tested using cultivars of Triticum aestivum and Pisum sativum on seedlings of up to 1 week old. The accuracy of the measured morphometric parameters was comparable with that obtained using ImageJ and manual measurements. Possible applications of Morley include dose-dependent laboratory tests for germination affected by new bioactive compounds and fertilizers.

Image analysis is widely applied in plant science for phenotyping and monitoring botanic and agricultural species. Although a lot of software is available, tools integrating image analysis and statistical assessment of seedling growth in large groups of plants are limited or absent, and do not cover the needs of the researchers. In this study, we developed Morley, a free, open-source graphical user interface written in Python. Morley automates the following workflow: (1) group-wise analysis of a few thousand seedlings from multiple images; (2) recognition of seeds, shoots and roots in seedling images; (3) calculation of shoot and root lengths and surface areas, (4) evaluation of statistically significant differences between plant groups, (5) calculation of germination rates, (6) visualization and interpretation. Morley is designed for laboratory studies of biotic effects on seedling growth, when molecular mechanisms underlying morphometric changes are analyzed. Performance was tested using cultivars of T. aestivum, P. sativum on seedlings of up to 1 week old. Accuracy of the measured morphometric parameters was comparable with the ones obtained using ImageJ and manual measurements. Dose-dependent laboratory tests for germination affected by new bioactive compounds and fertilizers, assuming extraction of seedlings from a substrate and/or dissection are among the suggested applications.

The structure of shock waves in pressed porous samples of nickel nanoparticles was investigated in a series of uniaxial planar plate impact experiments in the pressure range of 1.6–7.1 GPa. The initial porosity of the samples was about 50%. Wave profiles were obtained using laser velocimetry techniques. The nanomaterial demonstrated a complex response to shock loading including the development of a two-wave structure associated with precursor and compaction waves. The effect on profiles and measurements of the observed precursor reverberations propagating between the front of a compaction wave and a monitored sample surface was described. The obtained wave profiles were used to estimate the thicknesses of precursor and compaction wave fronts.

Carbon-encapsulated iron nanoparticles (Fe@C) with a mean diameter of 15 nm have been synthesized using evaporation–condensation flow–levitation method by the direct iron-carbon gas-phase reaction at high temperatures. Further, Fe@C were stabilized with bovine serum albumin (BSA) coating, and their electromagnetic properties were evaluated to test their performance in magnetic hyperthermia therapy (MHT) through a specific absorption rate (SAR). Heat generation was observed at different Fe@C concentrations (1, 2.5, and 5 mg/mL) when applied 331 kHz and 60 kA/m of an alternating magnetic field, resulting in SAR values of 437.64, 129.36, and 50.4 W/g for each concentration, respectively. Having such high SAR values at low concentrations, obtained material is ideal for use in MHT.

The shock compression of porous nickel from nanosized particles nNi was studied at a pressure range of 4–61 GPa. The average size of the nNi particles was 50 nm, and the porosity of the samples was 50%. Plane shock waves in the samples were generated by the impact of aluminum plates accelerated to velocities ranging from 0.8 to 5 km/s. Laser interferometry was used to monitor particle velocity histories at the interface between the samples and water or LiF windows. The data obtained at pressures below 8 GPa showed a complex shock wave profile with the formation of an elastic precursor wave. The shock Hugoniot and data on the expansion isentropes were obtained. The Hugoniot of nanosized nNi coincided within the experimental errors with the Hugoniot of micron-sized nickel. The Hugoniot calculated on the basis of the equation of state for porous nickel was in good agreement with that of experimental data. It has been established that in the middle pressure range (20–35 GPa), the expansion isentropes in the “pressure–particle velocity” coordinates become noticeably flatter with a significant increase in the particle velocity. The reason for this phenomenon is still unclear. An assumption was made about the onset of particle melting upon reaching pressures above 15 GPa.

Nanopowders of Fe-C system are synthesized via modified Guen-Miller Flow-Levitation method by in situ reaction of nascent iron nanoparticles with acetylene. Morphology, internal structure, chemical and phase composition are studied by electron microscopy methods, including electron diffraction and element analysis, X-ray phase analysis and CNHS chemical analysis. It is shown that depending on the parameters of the reaction with acetylene (temperature, concentration), particles composition can vary from pure iron with thin carbon coating complex composition consisting predominantly of iron carbide.

Laboratory automated equipment for synthesis of ultrafine particles of metals, alloys and metal compounds via evaporation-condensation Flow-Levitation Guen-Miller method combined with crucible method using high-frequency (440 kHz) electromagnetic field for heating is described. The equipment synthesizes the said particles and multilayer core-shell structures with mean size ranging from tens to hundreds of nanometers with output from grams to tens of grams per hour. Synthesized particles may be collected into container with inert gas, or into non-volatile liquid, or in situ passivated with air for further handling. Examples of synthesized particles are presented.

Nanopowders of titanium compounds TiH₂ and TiC are synthesized via Flow-Levitation method using in situ reaction of nascent titanium nanoparticles with the proper reactants. The influence of manufacturing parameters on the composition and the internal structure of the synthesized nanoparticles is examined. Study of TiH₂ nanoparticles using thermal methods revealed hydrogen evolution within the narrow temperature range (390-510°C), while hydrogen evolution temperature of the commercial samples is higher than 500°C.