Leonid Grunin

Dr. Leonid Grunin

Department of Physics, Volga State University of Technology, 424000 Yoshkar-Ola, Russia

Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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8 January 2022 in Legume Science
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OTOzan Tas
Ozan Tas
ÜEÜlkü Ertugrul
Ülkü Ertugrul
LGLeonid Grunin
Leonid Grunin
MOMecit Halil Oztop
Mecit Halil Oztop
Legume flours are great sources of protein, dietary fiber, starch, minerals, and vitamins. In recent years, the utilization of different legume flours in food systems has gained attention due to their sustainable and functional properties. This study aimed to characterize and examine the water interactions of different legume flours: navy bean, chickpea, pea, and lentil. For this purpose, in addition to the standard techniques (proximal analysis, Fourier transform infrared, protein solubility, and water solubility/absorption index), time‐domain nuclear magnetic resonance (TD‐NMR) relaxometry was also performed to explain the molecular interactions in the flours. Based on the results, carbohydrate and protein content of legume flours varied from 67.44 to 72.23 (g/100 g dw) and 23.19 to 27.03 (g/100 g dw) with low fat (0.86–5.44 [g/100 g dw]) and moisture content (6.01–8.14 [g/100 g dw]). Despite the slight differences in their compositions being small, moisture, protein, and carbohydrate contents influenced flour–water interactions. Thus, flour–water mixtures were assessed, and findings showed that water solubility index (WSI) followed the order: chickpea > lentil > navy bean > pea, whereas water absorption index (WAI) followed the order: pea > navy bean > lentil > chickpea. T2 relaxation times measured by NMR and protein solubility results were also in accordance with these results. The results of this study demonstrated that legume flours that were investigated offered potential for commercial applications. Because various food applications require different flour–water interactions, a suitable flour can be selected by considering these results.

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Marina GorbunovaMarina Gorbunova
Marina Gorbunova
LGLeonid Grunin
Leonid Grunin
RMRobert Morris
Robert Morris
AIArina Imamutdinova
Arina Imamutdinova
In 2020, we published a review on the study of semi-crystalline thermoplastic polyurethane elastomers and composites based on the shape memory effect. The shape recovery ability of such polymers is determined by their sensitivity to temperature, moisture, and magnetic or electric fields, which in turn are dependent on the chemical properties and composition of the matrix and the nanofiller. Nanocellulose is a type of nanomaterial with high strength, high specific surface area and high surface energy. Additionally, it is nontoxic, biocompatible, environmentally friendly, and can be extracted from biomass resources. Thanks to these properties, nanocellulose can be used to enhance the mechanical properties of polymer matrices with shape memory effect and as a switching element of shape memory. This review discusses the methods for producing and properties of nanocellulose-based thermo-, moisture-, and pH-sensitive polyurethane composites. The synergistic effect of nanocellulose and carbon nanofillers and possible applications of nanocellulose-based thermoplastic polyurethane biocomposites with shape memory effect are discussed. A brief description of nanocellulose terminology is also given, along with the structure of shape memory thermoplastic polyurethanes. There is significant interest in such materials for three primary reasons: the possibility of creating a new generation of biomaterials, improving the environmental friendliness of existing materials, and exploiting the natural renewability of cellulose sources.

15 April 2022 in Foods
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OTOzan Tas
Ozan Tas
ÜEÜlkü Ertugrul
Ülkü Ertugrul
LGLeonid Grunin
Leonid Grunin
MOMecit Halil Oztop
Mecit Halil Oztop
The hydration behavior of sugars varies from each other and examining the underlying mechanism is challenging. In this study, the hydration behavior of glucose, fructose, allulose (aka rare sugar), and sucrose have been explored using different Time Domain Nuclear Magnetic Resonance (TD-NMR) approaches (relaxation times, self-diffusion, and Magic Sandwich Echo (MSE)). For that purpose, the effects of different sugar concentrations (2.5%, 5%, 10%, 15%, 20%, 30%, and 40%) (w/v) and hydration at different times for 1 day were investigated by T2 relaxation times and self-diffusion coefficients. Crystallinity values of the solid and hydrated sugars were also determined with MSE. Change in T2 relaxation times with concentration showed that the fastest binding with water (parallel with the shortest T2 values) was observed for sucrose for all concentrations followed by glucose, fructose, and allulose. Furthermore, dependency of T2 relaxation times with hydration time showed that sucrose was the fastest in binding with water followed by glucose, fructose, and allulose. The study showed that allulose, one of the most famous rare sugars that is known to be a natural low-calorie sugar alternative, had the lowest interaction with water than the other sugars. TD-NMR was suggested as a practical, quick, and accurate technique to determine the hydration behavior of sugars.

29 December 2021 in Polymers
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AAAlexandre Alentiev
Alexandre Alentiev
ILIvan Levin
Ivan Levin
NBNikolay Belov
Nikolay Belov
RNRoman Yu Nikiforov
Roman Yu Nikiforov
SCSergey V. Chirkov
Sergey V. Chirkov
LGLeonid Grunin
Leonid Grunin
Poly-2,6-dimethylphenylene oxide (PPO) film samples with varying degrees of crystallinity (from 0 to 69%) were obtained by means of different techniques. The films were studied by various physicochemical methods (Fourier-transform infrared spectroscopy, positron annihilation lifetime spectroscopy, X-ray diffraction, and 1H nuclear magnetic resonance relaxation). Solubility coefficients of gases in the PPO samples were measured via sorption isotherms of gases by volumetric technique with chromatographic detection. The apparent activation energy of permeation and the activation energy of diffusion of all gases were estimated based on temperature dependences of gas permeability and diffusivity for amorphous and semi-crystalline PPO in the range of 20–50 °C. The peculiarities of free volume, density, and thermal properties of gas transport confirm the nanoporosity of the gas-permeable crystalline phase of PPO. So, the PPO can be included in the group of organic molecular sieves.

12 May 2021 in Inorganics
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YAYamen Albadi
Yamen Albadi
MIMaria Ivanova
Maria Ivanova
LGLeonid Grunin
Leonid Grunin
KMKirill D Martinson
Kirill D Martinson
MCMaria I. Chebanenko
Maria I. Chebanenko
VPVadim Igorevich Popkov
Vadim Igorevich Popkov
Nanocrystals of gadolinium orthoferrite (GdFeO3) with morphology close to isometric and superparamagnetic behavior were successfully synthesized using direct, reverse and microreactor co-precipitation of gadolinium and iron(III) hydroxides with their subsequent heat treatment in the air. The obtained samples were investigated by PXRD, FTIR, low-temperature nitrogen adsorption-desorption measurements, HRTEM, SAED, DRS and vibration magnetometry. According to the X-ray diffraction patterns, the GdFeO3 nanocrystals obtained using direct co-precipitation have the smallest average size, while the GdFeO3 nanocrystals obtained using reverse and microreactor co-precipitation have approximately the same average size. It was shown that the characteristic particle size values are much larger than the corresponding values of the average crystallite size, which indicates the aggregation of the obtained GdFeO3 nanocrystals. The GdFeO3 nanocrystals obtained using direct co-precipitation aggregate more than the GdFeO3 nanocrystals obtained using reverse co-precipitation, which, in turn, tend to aggregate more strongly than the GdFeO3 nanocrystals obtained using microreactor co-precipitation. The bandgap of the obtained GdFeO3 nanocrystals decreases with decreasing crystallite size, which is apparently due to their aggregation. The colloidal solutions of the obtained GdFeO3 nanocrystals with different concentrations were investigated by 1H NMR to measure the T1 and T2 relaxation times. Based on the obtained r2/r1 ratios, the GdFeO3 nanocrystals obtained using microreactor, direct and reverse co-precipitation may be classified as T1, T2 and T1–T2 dual-modal MRI contrast agents, respectively.

1 March 2017 in Biophysics
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Journal Article
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LGLeonid Grunin
Leonid Grunin
YGY. B. Grunin
Y. B. Grunin
ENE. A. Nikolskaya
E. A. Nikolskaya
NSNadezhda Sheveleva
Nadezhda Sheveleva
INI. A. Nikolaev
I. A. Nikolaev
The goal of this paper is a systematic investigation of changes in the supramolecular structure of cellulose during its water uptake. The main attention is concentrated on the analysis of the mechanism of dispersion of microfibrils by proton NMR relaxation techniques. Spin diffusion NMR experiments made it possible to estimate the linear dimensions of the surface thickness of cellulose crystallites and the average depth of micropores that are formed between elementary fibrils, as well as the character of the filling of micropores during adsorption. It has been shown that when the relative water content gradually increases to 7–8%, water molecules occupy the space between cellulose microfibrils, which is accompanied by an increase in the pore sizes and their specific surface area and a simultaneous decrease in the degree of crystallinity. Upon acquiring a free induction decay signal, a magic sandwich echo sequence was used, due to which the accuracy and information value of the results were considerably improved.