Institute of Mechanics and Engineering

Flax (Linum usitatissimum L.) fibers originate from procambial cells of the protophloem and develop in cortical bundles that encircle the vascular cylinder. We determined the polysaccharide composition of the cell walls from various organs of the developing flax plant, from fiber-rich strips peeled from the stem, and from the xylem. Ammonium oxalate-soluble polysaccharides from all tissues contained 5-linked arabinans with low degrees of branching, rhamnogalacturonans, and polygalacturonic acid. The fiber-rich peels contained, in addition, substantial amounts of a buffer-soluble, 4-linked galactan branched at the 0-2 and 0-3 positions with nonreducing terminal-galactosyl units. The cross-linking glycans from all tissues were (fucogalacto)xyloglucan, typical of type-I cell walls, xylans containing (1->)-[beta]-D-xylosyl units branched exclusively at the xylosyl O-2 with t-(4-O-methyl)-glucosyluronic acid units, and (galacto)glucomannans. Tissues containing predominantly primary cell wall contained a larger proportion of xyloglucan. The xylem cells were composed of about 60% 4-xylans, 32% cellulose, and small amounts of pectin and the other cross-linking polysaccharides. The noncellulosic polysaccharides of flax exhibit an uncommonly low degree of branching compared to similar polysaccharides from other flowering plants. Although the relative abundance of the various noncellulosic polysaccharides varies widely among the different cell types, the linkage structure and degree of branching of several of the noncellulosic polysaccharides are invariant.

Block diagram of the methods covered in the review for assessment of free fatty acids in oils and fats.

The dielectric spectroscopy method was applied to the investigation of water absorbed on the inner surface of porous glass. The measurements were done using broad band dielectric spectrometry (BBDS) over a wide range of frequency (20 Hz to 1 MHz) and temperature (−100 °C to +300 °C). The dielectric response was found to be very sensitive to the geometrical micro- and mesostructural features of the porous matrix and the structure and mobility of the water filling the pores. The hindered dynamics of water molecules located within the pores and affected by the surfaces reflect the geometrical structure of the porous matrix. The analysis of the dielectric parameters as a function of the temperature enabled us to characterize the physical parameters of the dielectric spectra over an extended frequency range.

Review Articles Nonlinear Oscillations of a Gas in a Tube M. A. Ilgamov, M. A. Ilgamov Institute of Mechanics, Russian Academy of Sciences, 2/31, Lobachevsky str, 420111, Kazan, Russia Search for other works by this author on: This Site PubMed Google Scholar R. G. Zaripov, R. G. Zaripov Institute of Mechanics, Russian Academy of Sciences, 2/31, Lobachevsky str, 420111, Kazan, Russia Search for other works by this author on: This Site PubMed Google Scholar R. G. Galiullin, R. G. Galiullin Department of Physics, Kazan State University, 18, Lenin str, 420008, Kazan, Russia Search for other works by this author on: This Site PubMed Google Scholar V. B. Repin V. B. Repin Kazan Technological University, 68, K. Marx str, 420015, Kazan, Russia Search for other works by this author on: This Site PubMed Google Scholar Author and Article Information M. A. Ilgamov Institute of Mechanics, Russian Academy of Sciences, 2/31, Lobachevsky str, 420111, Kazan, Russia R. G. Zaripov Institute of Mechanics, Russian Academy of Sciences, 2/31, Lobachevsky str, 420111, Kazan, Russia R. G. Galiullin Department of Physics, Kazan State University, 18, Lenin str, 420008, Kazan, Russia V. B. Repin Kazan Technological University, 68, K. Marx str, 420015, Kazan, Russia Appl. Mech. Rev. Mar 1996, 49(3): 137-154 (18 pages) https://doi.org/10.1115/1.3101922 Published Online: March 1, 1996 Article history Online: April 20, 2009

Studies of the activity levels of the fungal cell wall degradative enzyme, β‐l,3‐glucanase, were carried out with Zea mays L. embryogenie callus cultures and kernels of genotypes with different abilities to resist aflatoxin formation on the ears. Dual‐culture experiments of the aflatoxin forming fungus, Aspergillus flavus Link: Fr. with maize callus, demonstrated that the growth of A. flavus on plates was inhibited more by callus of a resistant genotype (Tex 6 ✕ Mol7 denoted T✕M) than by a sensitive genotype (Pa91). The inhibition correlated with the activity levels of β‐1,3‐glucanase in the callus and in the culture medium. The presence of the fungus caused an increase in enzyme activity in T✕M but not in Pa91 callus. Direct treatment of callus of both genotypes with A. flavus spores caused the amount of callose to increase within 30 min. An elevated β‐l,3‐glucanase activity in maize kernels was also correlated with lower A. flavus infection observed in the resistant genotype (Tex 6) compared with a susceptible one (B73). Fungal inoculation of the ears increased the enzyme activities both in kernels in contact with and not in contact with the fungus. These studies indicate that β‐l,3‐glucanase activity may have a role in the inhibition of growth of the A. flavus fungus, that maize embryogenic callus and kernels do respond to the presence of this nonpathogenic fungus, and that these systems might be useful in further plant‐fungal interaction studies.

Incubations of [1-14C]linoleic acid or [1-14C]-(9Z,11E, 13S)-13-hydropero xy-9,11-octadecadienoic acid (13-HPOD) with juice of garlic bulbs lead to the formation of one predominant labelled product, viz., the novel divinyl ether (9Z,11E, 1'E)-12-(1'-hexenyloxy)-9,11-dodecadienoic acid ('etheroleic acid'). With lesser efficiency [1-14C]alpha-linolenic acid or [1-14C](9Z,11E, 13S,15Z)-13-hydroperoxy-9,11,15-octadecatrienoic acid (13-HPOT) are converted in this way into (9Z,11E,1'E,1'E,3'Z)-12-(1',3'-hexadienyloxy)-9,11- dodecadienoic acid ('etherolenic acid'). Thus, garlic bulbs possess the activity of a new 13-hydroperoxide-specific divinyl ether synthase.

Fifteen patients with prominent positive symptoms of schizophrenia and 15 normal controls performed verbal prosodic and pure musical discrimination tasks, with changes in pitch and timing parameters. The patients' performance was comparable to that of controls on the discrimination of terminal pitch changes, but significantly poorer on the more difficult internal pitch discrimination. The latter deficit was positively correlated with the severity of their positive symptoms. The results suggest that patients have a deficit in processing fundamental aspects of prosody, which is associated with the presence of positive symptoms.

The potential of big data to support businesses has been demonstrated in financial services, manufacturing, and telecommunications. Here, we report on efforts to enter a new data era in plant breeding by collecting genomic and phenotypic information from 12,858 wheat genotypes representing 6575 single-cross hybrids and 6283 inbred lines that were evaluated in six experimental series for yield in field trials encompassing ~125,000 plots. Integrating data resulted in twofold higher prediction ability compared with cases in which hybrid performance was predicted across individual experimental series. Our results suggest that combining data across breeding programs is a particularly appropriate strategy to exploit the potential of big data for predictive plant breeding. This paradigm shift can contribute to increasing yield and resilience, which is needed to feed the growing world population.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 17 CO-oxidizing anaerobic microorganisms . . . . . . . . . . . . . . . . . . . . . . . . 417 CO dehydrogenases of anaerobic bacteria . . . . . . . . . . . . . . . . . . . . . . . 4 18 Electron acceptors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 18 Oxygen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419 Thermostability ant1 temperature optim~1111 . . . . . . . . . . . . . . . . . . . . . . . 419 pH o p t i ~ n ~ ~ m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 19 Inhibitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419 Localization of CO dehydrogenase . . . . . . . . . . . . . . . . . . . . . . . . . . . 419 Synthesis and regulation of CO dehydrogenase activity . . . . . . . . . . . . . . . . 420 Role of CO tlehydrogenase in the metabolism of anaerobic bacteria . . . . . . . . . . 420 Practical application of CO-oxidizing microorganisms . . . . . . . . . . . . . . . . 42 1 Key r~9orrl.s: carbon monoxide, CO dehydrogenase.

Metabolism of [1-14C]linolenic acid, 13-hydroperoxy-8(Z),11(E),15(Z)-[1-14C]octadecatrienoic acid (13-HPOT) and 9-hydroperoxy-10(E),12(Z),15(Z)-[1-14C]octadecatrienoic acid (9-HPOT) was studied by enzyme preparations from flax, wheat and corn seeds, containing two enzymes of fatty acid metabolism, namely, lipoxygenase and hydroperoxide dehydrase. Along with the previously known products of the hydroperoxide dehydrase pathway, the radiolabel was incorporated into some more polar metabolites. These polar products 1 and 4, formed from 13-HPOT and 9-HPOT, respectively, were purified by reversed-phase and normal-phase HPLC, and investigated by ultraviolet spectroscopy, chemical-ionization and electron-impact mass spectrometry, and 1H-NMR. The data obtained suggest that metabolites 1 and 4 are 9-hydroperoxy-12-oxo-13-hydroxy-10(E),15(Z)-octadecadienoic acid and 9-hydroxy-10-oxo-13-hydroperoxy-11(E),15(Z)-octadecadienoic acid, respectively. 12-oxo-13-hydroxy-9(Z),15(Z)-[1-14C]octadecadienoic acid (12,13-alpha-ketol) and 9-hydroxy-10-oxo-12(Z),15(Z)-[1-14C]octadecadienoic acid (9,10-alpha-keto) are the direct precursors of metabolites 1 and 4, respectively. Metabolites 1 and 4 are formed from the corresponding HPOT precursors in two stages; (a) conversion of hydroperoxide into the alpha-ketol by hydroperoxide dehydrase and (b) the lipoxygenase oxidation of the alpha-ketol. Different lipoxygenases were found to oxidize alpha-ketols. Oxidation of the 3(Z)-buten-1-onyl moiety of alpha-ketols presents an unusual and previously unknown type of lipoxygenase reaction.

The cavitation bubble dynamics, the variation of pressure and velocity fields of the surrounding liquid in the process of the bubble axisymmetric compression near a planar solid wall are considered. It is assumed that the liquid is at rest at the initial moment of time, and the bubble has a spheroidal shape. The liquid is assumed inviscid and incompressible, its motion being potential. The bubble surface deformation and the liquid velocity on the surface are computed by the Euler scheme using the boundary element method until the moment of the collision of some parts of the bubble surface with one another. The influence of the distance of the bubble from the wall and its initial nonsphericity on the liquid pressure and velocity fields, the bubble shape, and the pressure inside the bubble at the end of the time interval under consideration are studied. The maximum pressure in liquid is shown to realize at the bottom of the cumulative jet arising at the bubble collapse with direction to the wall. In the upper part of this jet, the velocity and pressure are practically constant, and the pressure in the jet is approximately equal to the pressure in the bubble.

The dynamics of a bubble near a local axisymmetric convexity or concavity, cosine-like in the axial section, on a plane rigid wall is studied under conditions of formation of a cumulative liquid jet directed to the wall. The study is performed by the boundary element method. Our main attention is focused on the bubble collapse characteristics at the moment tc when the jet impacts on the bubble surface part near the wall, namely, on the jet tip velocity and radius, the internal bubble pressure, the distance between the bubble and the uneven region of the wall, and so on. These characteristics are of interest since they, to a large extent, determine the destructive potential of cavitation. The dependences of these characteristics on the radius of the non-plane region of the wall, the depth of the concave region, the height of the convex region, and the local character of the wall unevenness have been investigated. To estimate the effect of the local character of the wall unevenness, the cases of completely concave and convex walls in the form of blunt conical surfaces are used for comparison. It has been found, in particular, that with changing radius of the convex region of the wall, the bubble shape at the moment tc varies significantly: the shape diversity includes the profiles with a gas microcavity in front of the impacting jet tip, an emerging second oppositely directed jet, and a relatively large area of the jet tip impact at its beginning.

A mathematical model is presented for determining the oblique incidence of an acoustic wave at both a boundary and layer of a gas–drop mixture or a bubbly liquid of finite thickness. The basic wave reflection and transmission patterns are established for the incidence of a low-frequency acoustic wave at an interface between a pure gas and a gas–drop mixture, as well as between a pure and bubbly liquid. A range of varying volume fractions for a drop is determined, for which the zero value of the reflection coefficient is possible for low frequencies at oblique incidence. It is shown that the reflection coefficient will never be zero at angles of incidence above 24.5° from a gas–drop mixture at a pure gas boundary; however, when a wave is incident from a pure gas at a gas–drop mixture boundary, a zero reflection coefficient is possible for nonzero angles of incidence and the volume fraction of inclusions. The results of calculating reflection of an acoustic wave from a two-phase layer of a medium with a finite thickness are presented. It is established that the minimum reflection coefficient is possible depending on the perturbation frequency for a certain range of angles of incidence for the boundary or the layer of the gas–drop mixture, which is governed mainly by difference in densities between it and the pure gas.

We present a planar one-dimensional theoretical model and numerical solutions for the process of the formation of methane gas hydrate by injecting gas into a porous reservoir partially saturated with water. The case where the intensity of formation of the gas hydrate is limited by the diffusion of gas through a hydrate layer formed between water and gas in the pore channel core is considered. Within this process, the kinetics of hydrate formation is determined by empirical parameter D, having the dimension of a diffusion coefficient (m2/s). The effect of the value of this parameter on the characteristics of the hydrate formation process is studied depending on the parameters that determine the initial state of the porous reservoir and its porosity and permeability characteristics. The equilibrium mechanism of hydrate formation is considered, which is a limit adopted by the diffusion pattern that corresponds to the case of D → ∞.

catalyst has a high density of active edges, and it is a non-noble metal catalyst for the hydrogen evolution reaction. The present findings provide an alternative strategy and an active nonprecious material for the development of energy-related applications.

Candida albicans is a widespread commensal fungus with substantial pathogenic potential and steadily increasing resistance to current antifungal drugs. It is known to be resistant to cycloheximide (CHX) that binds to the E–transfer RNA binding site of the ribosome. Because of lack of structural information, it is neither possible to understand the nature of the resistance nor to develop novel inhibitors. To overcome this issue, we determined the structure of the vacant C. albicans 80 S ribosome at 2.3 angstroms and its complexes with bound inhibitors at resolutions better than 2.9 angstroms using cryo–electron microscopy. Our structures reveal how a change in a conserved amino acid in ribosomal protein eL42 explains CHX resistance in C. albicans and forms a basis for further antifungal drug development.

This study presents the development of a highly selective and sensitive electrochemical sensor for the determination of melamine from aqueous environments.

A mathematical model is presented for the propagation of plane, spherical, and cylindrical sound waves in a liquid containing polydisperse vapor–gas bubbles with allowance for phase transitions. A system of integro-differential equations is constructed to describe perturbed motion of a two-phase mixture, and a dispersion relation is derived. An expression for equilibrium sound velocity is obtained for a gas–liquid or vapor–liquid mixture. The theoretical results agree well with the known experimental data. The dispersion curves obtained for the phase velocity and the attenuation coefficient in a mixture of water with vapor–gas bubbles are compared for various values of vapor concentration in the bubbles and various bubble distributions in size. The evolution of pressure pulses of plane and cylindrical waves is demonstrated for different values of the initial vapor concentration in bubbles. The calculated frequency dependence of the phase sound velocity in a mixture of water with vapor bubbles is compared with experimental data.

The propagation of acoustic waves in multifractional mixtures of a liquid with vapor-gas and gas bubbles of different sizes and different compositions with phase transitions is investigated. The dispersed phase consists of N + M fractions having various gases in bubbles and different in the bubble radii. Phase transitions accounted for N fractions. The total bubble volume concentration is small (less than 1%). A system of differential equations of the mixture motion is developed, and the dispersion relation is derived. It is shown that the dispersion and dissipation of acoustic waves depends largely on the presence of bubbles of various proportions in the composition of the disperse phase. It is found that the replacement of a fraction of vaporgas bubbles in the monodisperse bubbly mixture with phase transitions for gas bubbles with different thermophysical properties, depending on the type of gas, can lead to both a decrease and an increase in the attenuation coefficient in the low-frequency region.

nanostructures can be of great importance for diverse electrochemical applications due to their excellent electrochemical activity and large surface area.