Dynamics of the process of gas transport into the body using a mathematical model

Dynamics of mass-transport of oxygen, carbon dioxide, and inert gases in lungs, blood, and tissues, as well as gas transport through alveolar capillary and erythrocyte membranes at rest and during exercise under normal and increased ambient pressures, were studied on a mathematical model. The model consists of 34 differential and 58 algebraic equations and makes it possible to estimate the dynamics of changes of over 90 parameters. The effect of various factors: duration of the respiratory cycle, tidal volume, airways resistance, the surface of diffusion, the resistance of alveolar-capillary wall, erythrocyte membrane, ventilation-perfusion relations, pulmonary blood shunts, blood supply to the tissues, Haldane and Verigo-Bohr effect, buffer capacity of the blood, and others) on the mass-transport of gases were quantitatively estimated.     

Effect of lithium salts on the ultrastructure of isolated cerebral mitochondria exposed to the serum of schizophrenic patients

The author studied the influence of lithium chlorous on the ultrastructure of isolated brain hemispheric mitochondria of cats, subjected to the action of the blood sera of schizophrenic patients and normal donors. The data demonstrated similar changes in the mitochondria structures under the action of schizophrenic patients and normals. Lithium to a certain extent prevents disorders in the mitochondria structure which appear in an incubation with the blood serum. This effect of lithium is expressed in the same way in the presence of the blood serum of schizophrenic patients and normal donors and is considered to be nonspecific.     

Constancy of the Surface Energy during the Melting of a Nanocrystal

The relation for the surface free energy @sgr; as a function of size and shape of a nanocrystal is derived. The nanocrystal has the form of a parallelepiped with a square base. The ratio of the lateral edge length to the base edge length f defines the shape of a system. It is shown that the value of @sgr; decreases with degreasing number of atoms N in a nanocrystal. The higher the deviation of the form parameter f from unity, the stronger the dependence @sgr;(N). It is found that the surface free energy decreases with the temperature T; in so doing, the quantity (d/T) is the greater, the smaller the size of the nanocrystal or the greater the deviation of the nanocrystal shape from the most thermodynamically stable, cubic, shape. It is shown that the nanocrystal melts when its surface energy decreases to a certain value independent of size and shape. The conditions are discussed under which the crystal fragmentation and dendritic growth are realized.     

The behavior of self-diffusion coefficient under conditions of varying isotope composition of crystal

The variation of diffusion parameters with varying isotope composition in both the high-temperature and low-temperature region is studied in view of the dependence of the parameters of interatomic potential on the atomic mass. It is demonstrated that the isotopic dependence of the coefficient of self-diffusion is insignificant at high temperatures. However, upon transition to low temperatures, the difference between the coefficients of self-diffusion in isotopically different crystals becomes appreciable. Calculations for diamond and lithium reveal that the coefficient of self-diffusion in the low-temperature region decreases by one-three orders of magnitude during transition from ¹²C to ¹³C and increases by an order of magnitude during transition from ⁷Li to ⁶Li. This effect is associated with quantum tunneling at low temperatures and is caused by the presence of “zero-point oscillations” of atoms. It is demonstrated that, in the high-temperature region, the inclusion of isotopic dependence of the parameters of interatomic potential has a marked effect on the self-diffusion coefficient. The temperature dependence of self-diffusion coefficient is calculated, and temperatures are estimated below which the Arrhenius law is no longer valid.     

Modified combustion synthesis of γ-LiAlO2 using metal oxides

An alternative solution for the direct formation of γ-LiAlO₂ was presented by a modified combustion method, to apply it to rather simple systems, utilizing non-oxidizer compounds such as Al₂O₃ and LiOH, and urea as fuel. LiAlO₂ was prepared via non-stoichiometric 1:1, 1.5:1 and 2:1 of Li/Al molar ratios at 900 and 1000 °C for 5 min. Textural and structural characterization of γ-LiAlO₂ was performed. Also, the effect of different Li/Al molar ratios on material morphology and its stability before high gamma radiation gradients was evaluated. The results showed that the crystal structures of the obtained powders were γ-LiAlO₂ and α-LiAlO₂, depending on the Li/Al molar ratio. The results obtained demonstrate that γ-LiAlO₂ microbricks, polyhedral and laminar shapes can be successfully synthesized with the proposed method and without any subsequent process. Additionally, gamma irradiation showed that the γ-LiAlO₂ obtained does not decompose, forming only small amounts of Li₂CO₃. It can be established that the irradiation produces consolidation, which is not favourable for an efficient extraction of tritium. Finally, it could be demonstrated that nitrate precursors are not necessary in the combustion method to produce γ-LiAlO₂ with high purity.     

ABA during reproductive development in non-irrigated grapevines (Vitis vinifera L. cv. Tempranillo)

In grapevines, stomatal aperture decreases after a mid-morning peak during summer days. Afternoon stomatal closure increases in non-irrigated plants as water limitation progresses, which suggests the involvement of abscisic acid (ABA) in the control of stomatal aperture. The objective of this work was to study the seasonal and diurnal time-courses of CO₂ assimilation rate, leaf conductance, leaf water potential +, and ABA concentration in xylem sap, leaves, flowers and berries in non-irrigated field-grown Tempranillo grapevines throughout reproductive development. Leaf decreased throughout fruit development because water availability decreased towards the end of the reproductive cycle. CO₂ assimilation rate, leaf conductance and xylem ABA concentration also decreased during the course of the growing season. Combining all measurements xylem ABA was either not correlated, or only slightly correlated, with leaf water status + and daily leaf conductance, respectively. This lack of relationship indicates that xylem ABA during fruit ripening had functions other than provision of a non-hydraulic signal. On a seasonal basis, xylem ABA concentration measured in non-irrigated grapevines was well related to berry ABA concentration, especially at the end of fruit development (veraison and harvest).