Fabrication and optical properties of garnet ceramics based on Y3-xScxAl5O12 doped with ytterbium and erbium.

Optical ceramics YSAG:Yb,Er with an average grain size of 6 ± 1 microns were fabricated by vacuum sintering of nanocrystalline powders of the compositions Y2.34Yb0.45Er0.09Sc0.20Al4.92O12, Y1.66Yb0.45Er0.09Sc1.00Al4.80O12 and Y0.96Yb0.45Er0.09Sc1.70Al4.80O12. The linear transmittance coefficients of the YSAG:Yb,Er ceramic samples exceed 80% in the visible and infrared regions. The refractive index of ceramics increased from 1.827 to 1.859 with an increase in scandium content. The effect of scandium cations at the dodecahedral site of the YSAG crystal lattice on the optical and luminescence characteristics of Yb3+ (2F7/2 and 2F5/2) and Er3+ (4I15/2, 4I13/2, 4F9/2 and 4S13/2) in wavelength ranges of 530-690 nm, 890-1080 nm, and 1430-1680 nm was revealed.

Cytoprotective and Antioxidant Effects of Meconic Acid in Model Systems.

We studied the antioxidant and cytoprotective effects of meconic acid in the model systems. Meconic acid, similar to commercial drug Mexidol, reduced the intensity of chemiluminescence in the model system of yolk lipoproteins. Meconic acid also reduced the toxic effect of glutamate on neurons in the primary cerebellar culture, but had no effect on cell viability under normal conditions.

Neurotrophic Effect of Magnesium Comenate in Normal and under Conditions of Oxidative Stress in Culture of Chicken Spinal Ganglia.

The neurotrophic properties of magnesium comenate were studied under standard conditions and under conditions of oxidative stress. It was found that magnesium comenate has a stimulating effect on the neurotrophic processes of the spinal ganglia under normal conditions and under conditions of oxidative stress. Under standard conditions, magnesium comenate exhibits neurotrophic activity at a concentration of 0.0001 mM, under conditions of oxidative stress, magnesium comenate exhibits neurotrophic activity at concentration 0.1 mM.

[Antioxidant and anxiolytic effect of Bifidobacterium adolescentis and Lactobacillus acidophilus under conditions of normobaric hypoxia with hypercapnia].

Research in recent years has shown that there is a close connection between the brain and the intestine through neuronal, endocrine and immune pathways. The introduction of probiotics into the diet of animals and humans helps to reduce the level of anxiety and depression, as well as inflammatory processes during emotional stress. The aim of this work was to study the effect of intragastric administration of Bifidobacterium adolescentis and Lactobacillus acidophilus on oxidative processes in the brain tissues and the level of anxiety in rats under conditions of normoxia and acute hypoxia with hypercapnia. Material and methods. The experiment was performed on 64 male Wistar rats aged 2.5 months (body weight from 240 to 270 g). The animals were divided into 4 groups: group 1 - control; 2 - hypoxia; 3 - hypoxia + probiotics; 4 - probiotics. There were 16 animals in each group; half of them participated in the behavioral test, and the other half in the biochemical studies. Rats of groups 3 and 4 were orally administered lyophilized bacteria Bifidobacterium adolescentis MC-42, Lactobacillus acidophilus A-97, and Lactobacillus acidophilus A-630 for 30 days before hypoxia. The daily dose of probiotics was 1×109 CFU per animal, administered in a volume of 1 ml. Acute hypoxia with hypercapnia was simulated by placing rats in airtight vessels with a capacity of 1 L before the first agonal inhalation. A day later, in the brain tissues oxidative processes were assessed by the chemiluminescence method and by the level of malone dialdehyde (MDA). The activity of catalase in brain tissues was also determined. The level of anxiety of rats was investigated in the «elevated plus maze¼ test. Results. Compared to other groups, more intensive free radical oxidation took place in the brain tissues of hypoxified animals that did not receive B. adolescentis and L. acidophilus. There was a significant increase in chemiluminescence intensity and MDA level by 38 and 15%, respectively, compared with the control. In the brain tissues of these animals, catalase activity was reduced by 10% (p<0.01). Moreover, in the group of rats treated with B. adolescentis and L. acidophilus and subjected to acute hypoxia, the value of the light sum of chemiluminescence was 22% lower (p<0.01) than in the hypoxified group without taking probiotics, while the concentration of MDA and catalase activity remained at the level of physiological norms and did not differ from control. Hypoxified animals receiving biomass of lactobacteria and bifidobacteria had also a lower level of anxiety and a higher exploratory activity, expressed in an increase in the number of entries in the open and closed arms, a longer stay in the open arms and the center of the maze, and more frequent performance of orientation reactions and hanging. Conclusion. Pre-hypoxic administration of B. adolescentis and L. acidophilus reduces the development of oxidative stress in rat brain tissues and reduces anxiety indices in the "elevated plus maze" test, thereby exhibiting antioxidant and anxiolytic effects.

Neurotrophic Action of Comenic Acid and Its Derivatives Potassium Comenate and Calcium Comenate.

Using the model of cultured spinal ganglia, we demonstrated high neurotrophic activity of comenic acid and its derivatives potassium comenate and calcium comenate both under normal conditions and during oxidative stress. Calcium comenate in the norm as well as potassium and calcium comenates during oxidative stress demonstrate greater neurotrophic potency than comenic acid.

Influence of nanosilver on the efficiency of Pisum sativum crops germination.

The study is aimed to investigate the impact of silver nanoparticles on germination of Pisum sativum pea seeds. The influence of synthesized silver nanoparticles on root length and percentage of germinated seeds was revealed. It was found that nanosilver treatment agents do not affect the germination of pea seeds negatively at low concentrations. Also, the treatment of pea seeds with silver nanoparticles provide a significant positive effect on the root length of pea seeds.

Antioxidant and Antiamnestic Effects of Potassium Comenate and Comenic Acid under Conditions of Normobaric Hypoxia with Hypercapnia.

Potassium comenate and comenic acid exhibit manifest and virtually identical antioxidant activity under conditions of hypoxia with hypercapnia. The effects of these drugs on conditioned reflex training with positive reinforcement differ significantly. Potassium comenate promotes retention of the learning capacity and memory in hypoxic rats at the level of intact control, that is, exhibits a pronounced protective antiamnestic effect, while comenic acid only facilitates training of the conditioned reflex with positive reinforcement.

Comparative Analysis of Antioxidant Properties of Comenic Acid and Potassium Comenate in Modeled Immobilization Stress.

We studied antioxidant protective effect of comenic acid and potassium comenate in doses of 2, 4, and 8 mg/kg under conditions of oxidative stress in the brain of mice exposed to immobilization stress. Administration of potassium comenate and comenic acid in the above doses for 3 days before stress prevented the development of oxidative processes in the brain of stressed animals. The antioxidant effect of potassium comenate more pronounced.

Neuroprotective effect of potassium comenate against glutamate toxicity on the model of cultured rat cerebellar neurons.

The study demonstrated neuroprotective action of novel chemical agent, potassium salt of comenic acid, against the glutamate-induced cytotoxicity on the model of cultured cerebral neurons. Potassium comenate (0.001-1.0 mM) significantly decreased the rate of glutamateinduced neuronal death. The highest viability of the cultured neurons during postglutamate time was observed when potassium comenate was applied in a concentration of 0.1 mM.

[Influence of lithium salt of comenic acid on the state of oxidative processes in brain of stressed animals].

The influence of a new substance, lithium salt of comenic acid, on the oxidative processes in the brain of animals under the conditions of acute and long combined stress has been investigated. It is established that lithium comenate (1 and 2 mg/kg) exhibits pronounced dose-dependent antioxidative stress-protective effect, which is manifested in suppression of the hyperproduction of free radicals and depression of the content of malonic dialdehyde (a secondary product of lipid peroxidation) in the brain of stressed animals. The maximum antioxidative stress protection effect under the conditions of acute and long combined stress has been observed for lithium salt ofcomenic acid in a dose of 2 mg/kg.

Neuroprotector effect of comenic acid against cytotoxic action of glutamate in vitro in cultured neurons of lead-poisoned rat pups.

We demonstrated an increase in glutamate neurocytotoxicity in cultured cerebellar cells from rat pups subjected to lead poisoning during the prenatal development or early lactation period. The toxic effect of glutamate was weaker, if lead was applied in combination with antioxidant comenic acid. These data are discussed in view of practical use of comenic acid for the therapy of the brain tissues subjected to lead poisoning.

[Flavonoid correction of functional elasticity of erythrocyte membranes and hemorheological disorders during oxidative stress caused by chronic physical overstrain in mice].

Effect of a course of treatment by bioflavonoids quercetin and diquertin on the physical work capacity, oxidant and antioxidant status of organism, and hemorheological parameters and deformability of erythrocytes have been studied under conditions of chronic physical overstrain in mice caused by sequential extraordinary running load. The drugs effectively prevent the development of oxidative stress, loss of elasticity of erythrocyte membranes and growth in dynamic blood viscosity in microcirculatory link of hemodynamics. It is established that both bioflavonoids significantly increase the physical work capacity of animals and prevent from the development of physical overstrain syndrome.