New instruments for routine monitoring of structures at the Sayano-Shushenskoe hydroelectric station

Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 9, pp. 15–17, September, 1988.     

Two-Dimensional Force-Free Relaxation and Superdiffusion Governed by Fractional Kinetic Equations

Starting from the integral Chapman-Kolmogorov equation and the Langevin equations with a multivariate Levy noise, we consider possible generalization of a one-dimensional fractional kinetic equations. It is assumed that the Levy noise has independent components. As the result, we get fractional Fokker-Planck equation for the probability density function in a phase space and fractional Einstein-Smoluchowski equation for the probability density function in a real space. We consider force-free superdiffusion and relaxation described by fractional equations and carry out numerical simulation of these processes by solving the corresponding Langevin equations. Analytical and numerical results agree quantitatively.     

C60 Fullerene Reduces 3-Nitropropionic Acid-Induced Oxidative Stress Disorders and Mitochondrial Dysfunction in Rats by Modulation of p53, Bcl-2 and Nrf2 Targeted Proteins

C₆₀ fullerene as a potent free radical scavenger and antioxidant could be a beneficial means for neurodegenerative disease prevention or cure. The aim of the study was to define the effects of C₆₀ administration on mitochondrial dysfunction and oxidative stress disorders in a 3-nitropropionic acid (3-NPA)-induced rat model of Huntington’s disease. Animals received 3-NPA (30 mg/kg i.p.) once a day for 3 consecutive days. C₆₀ was applied at a dose of 0.5 mg/kg of body weight, i.p. daily over 5 days before (C₆₀ pre-treatment) and after 3-NPA exposure (C₆₀ post-treatment). Oxidative stress biomarkers, the activity of respiratory chain enzymes, the level of antioxidant defense, and pro- and antiapoptotic markers were analyzed in the brain and skeletal muscle mitochondria. The nuclear and cytosol Nrf2 protein expression, protein level of MnSOD, γ-glutamate-cysteine ligase (γ-GCLC), and glutathione-S-transferase (GSTP) as Nrf2 targets were evaluated. Our results indicated that C₆₀ can prevent 3-NPA-induced mitochondrial dysfunction through the restoring of mitochondrial complexes’ enzyme activity, ROS scavenging, modulating of pro/antioxidant balance and GSH/GSSG ratio, as well as inhibition of mitochondria-dependent apoptosis through the limitation of p53 mitochondrial translocation and increase in Bcl-2 protein expression. C₆₀ improved mitochondrial protection by strengthening the endogenous glutathione system via glutathione biosynthesis by up-regulating Nrf2 nuclear accumulation as well as GCLC and GSTP protein level.     

D-lactate-selective amperometric biosensor based on the mitochondrial fraction of Ogataea polymorpha recombinant cells

During the recent decades, a lot of data about the significance of D-lactate determination in food technology and quality control have been accumulated. Nowadays, the development of new methods for the determination of D-lactate is very relevant, especially with regard to biosensors. To construct a D-lactate-selective biosensor, we suggest using the mitochondria of recombinant yeast cells of Ogataea (Hansenula) polymorpha “tr6” (gcr1 catX/Δcyb2, prAOX_DLDH) overproducing D-lactate: cytochrome c-oxidoreductase (DLDH, EC 1.1.2.4) and lacking an L-lactate-specific enzyme (flavocytochrome b₂, E.C. 1.1.2.3). The usage of the pure enzyme is problematic due to the complexity of its isolation and stabilization because of the intramembranous localization of DLDH. The enzyme catalyzes D-lactate oxidation to pyruvate coupled with ferricytochrome c reduction to ferrocytochrome c. The constructed biosensor is characterized by high sensitivity (18.5 А·М⁻¹·m⁻²), a low detection limit (3 μM of D-lactate), wide linear ranges, good selectivity, and sufficient stability. The real samples' analysis of D-lactate in dairy products was performed, and high correlation of the obtained results with the reference approach (0.7 < r < 1) and literature data was demonstrated.     

Ultrasonic and eddy-current study of plastic deformation in austenitic-steel welds

The effect of plastic deformation of a 08Kh18N10T (analogue AISI321)-steel welded joint on electromagnetic and acoustic properties of the material has been studied by eddy-current and ultrasonic methods. It has been established that structural inhomogeneity in heat- affected zone leads to a nonuniform distribution of acoustic properties in the weld. The possibility for determining the plastic resource of material from ultrasonic data is demonstrated.     

A Novel Enzyme Biosensor Specific for Formaldehyde Based on pH-Sensitive Field Effect Transistors

An enzyme biosensor specific for formaldehyde has been developed using pH-sensitive field effect transistors (FET) as a transducer and alcohol oxidase (AOX) from Hansenula polymorpha as a sensitive element. The steady-state response time of the developed biosensor was 10–60 s. The linear dynamic range (in semi-logarithmic scale) of the sensor output signal corresponded to 10–300 mmol dm⁻³ formaldehyde concentration. The operational stability of the biosensor was not less than 7 h and the relative standard deviation approximately 1–3%. When stored at +4°C, the response was stable for more than 30 days. The biosensor demonstrated high specificity to formaldehyde with no potentiometric response to primary alcohols. The influence of buffer concentration and enzyme concentration in the biomembrane on the sensor signal was investigated. The specific biosensor could also be successfully used for highly selective, quantitative estimation of mercury ion in an aqueous solution. © 1997 SCI.     

Enhancement of photoluminescence and raman scattering in one-dimensional photonic crystals based on porous silicon

In porous-silicon-based multilayered structures that exhibit the properties of one-dimensional photonic crystals, an increase in the photoluminescence and Raman scattering intensities is observed upon optical excitation at the wavelength 1.064 μm. When the excitation wavelength falls within the edge of the photonic band gap of the structures, a multiple increase (by a factor larger than 400) in the efficiency of Raman scattering is detected. The effect is attributed to partial localization of excitation light and, correspondingly, to the much longer time of interaction of light with the material in the structures.