Findings and expansion of rare adventive species of plants in the Altai Territory

This paper contains previously unknown information about the appearance and expansion of a number of adventive species of plants new for the Altai Territory. They were discovered in 2008–2012 during the fieldwork tasks of the herbarium Altai State University, Barnaul. One of the species is invasive (quarantine plant for the Russian Federation) – Acroptilon repens (L.) DC. The range was about 10?ha. One of the species was listed as adventive for the first time – Briza maxima L. The species is sometimes cultivated as an ornamental plant. New locations were identified for three species previously found only in one area of the Altai Territory: (1) Scleranthus annuus L. – an agrophyte, a weed that spreads with cultivated crops; (2) Onopordon acanthium L. – a species that spreads in flood plains, along the highways, railways and pastures; and (3) Xanthium albinum (Widd.) H. Schulz – a plant, often seen along roadsides, wastelands and sandy riverbanks; only one reliable location within the Altai Territory was known for S. annuus and O. acanthium. Based on the classification of adventive elements of flora, A. repens was specified as agrophyte and xenophyte; B. maxima as horthophyte and ergasiofigophyte; S. annuus as agrophyte and xenophyte; O. acanthium; and X. albinum as dromophyte and acolucophyte.     

Effectiveness of optimal design with respect to computational models for laminated composite structures weakened by holes

The present work deals with the shape optimization of laminated structures via semianalytical sensitivity anslysis, based on linear programming. Particular attention is focused on the concise and correct finite element formulation of the problem taking into account explicit differentiation with respect to the control parameters. A series of numerical examples shows the influence of orthotropy parameters (treated as the level of anisotropy), stacking sequences, FE models and the employed 2-D plate theories of structures on the resulting optimal shapes.     

Pattern learning in humans and electronic learning nets

The letter reports on a previously unseen similarity between an associative memory model recently proposed for the brain and some electronic systems that have been developed for practical learning machines. This similarity is analysed, and its implications are discussed. Results of a comparison between the learning behaviour of an electronic network and a group of human subjects in a pattern-recognition task are given to complete the comparative study.     

Deformations in an infinite cylindrical shell restrained by elastic or rigid walls

Summary The contact problem of an infinite cylindrical shell with an elastic or a rigid foundation is investigated. A shear deformation non-linear shell theory is used in setting up the governing differential equations and the functional of total potential energy. The variations of contact pressure and domains are discussed for different shell parameters, friction and rigidity coefficients of foundation. The obtained results are compared with the results for geometrically linear shell theory. Some problems connected with the variational inequality formulation of the analysed unilateral boundary problem are also discussed.With 7 Figures     

Pattern-recognition properties of r.a.m./r.o.m. arrays

Arrays of r.a.m.s may be used as trainable logic devices in arrays whose object is to recognise patterns. The way in which such a system is organised is presented and some of the characteristics of the nature of the recognition are discussed     

The GC/AED studies on the reactions of sulfur mustard with oxidants

A gas chromatograph coupled with an atomic emission detector was used to identify and to determine the products formed on oxidation of sulfur mustard. The oxidation rate and the resulting oxidates were studied in relation to oxidant type and reaction medium parameters. Hydrogen peroxide, sodium hypochlorite, sodium perborate, potassium monopercarbonate, ammonium peroxydisulfate, potassium peroxymonosulfate (oxone), and tert-butyl peroxide were used as oxidants. Oxidations were run in aqueous media or in solvents of varying polarities. The oxidation rate was found to be strongly related to oxidant type: potassium peroxymonosulfate (oxone) and sodium hypochlorite were fast-acting oxidants; sodium perborate, hydrogen peroxide, ammonium peroxydisulfate, and sodium monopercarbonate were moderate oxidants; tert-butyl peroxide was the slowest-acting oxidant. In non-aqueous solvents, the oxidation rate was strongly related to solvent polarity. The higher the solvent polarity, the faster the oxidation rate. In the acid and neutral media, the mustard oxidation rates were comparable. In the alkaline medium, oxidation was evidently slower. A suitable choice of the initial oxidant-to-mustard concentration ratio allowed to control the type of the resulting mustard oxidates. As the pH of the reaction medium was increased, the reaction of elimination of hydrogen chloride from mustard oxidates becomes more and more intensive.     

Spatial distributions of residuals produced inside a spallation target

The spallation target model of an accelerator driven system (ADS), consisting of six 5 cm thick and 16 cm in diameter Pb segments, was constructed. Three sets of 17 Bi samples (1/2 inch in diameter and 1 mm thick) were placed in 3 Pb disc-shaped holders inside the target at 5, 10 and 15 cm from its front. After irradiation with 660 MeV proton beam gamma-spectra of radioisotopes produced in Bi were collected several times for each sample with the use of HPGe detectors in order to identify the radioisotopes and to determine their absolute activities. Their spatial distributions were then compared with respective values obtained in the calculations made with the use of FLUKA and/or MCNPX code. A fair agreement with the experiment has been observed.     

Lipidic membranes are potential "catalysts" in the ligand activity of the multifunctional pentapeptide neokyotorphin

Neokyotorphin (NKT) is a multifunctional pentapeptide that is involved in biological functions as diverse as analgesia, antihibernatic regulation and proliferation stimulus of tumour cells. The interaction of neokyotorphin with cell membranes is potentially important to all these multiple biological processes since receptor-mediated processes are thought to be involved in neokyotorphin action. Sargent and Schwyzer proposed in their "membrane catalysis" model that ligands interact with membrane lipids in order to adopt the necessary conformation for cell receptors. We have used fluorescence techniques to study the depth, orientation and extent of incorporation of NKT with model membrane systems (lipidic vesicles). The roles of lipid charge, membrane phase and sterol presence were investigated. The phenolic ring of tyrosine is located in a shallow position in membranes. The extent of partition is less in gel crystalline membranes than in liquid crystalline membranes. Addition of cholesterol causes a reorientation of the tyrosine ring at the interface of lipidic bilayers. Lipidic membranes meet all the conditions required for acting as potential "catalysts" in the ligand activity of the multifunctional pentapeptide NKT, because they modulate the exposure and orientation of the phenolic ring, which is most likely involved in docking to receptors.     

IMAGE-WARP: a real-space restoration method for high-resolution STEM images using quantitative HRTEM analysis

We have developed a new method for processing distorted high-resolution scanning transmission electron microscopy (STEM) images. The method is based on finding the displaced vertices in the experimental STEM image and warping to geometrically correct reference grid of the object. As a reference grid for warping a structural model obtained using a high-resolution transmission electron microscopy (HRTEM) analysis of the area of interest is utilised. Combined with quantitative HRTEM analysis the IMAGE-WARP method provides a real-space restoration of high-resolution high-angle annular dark-field (HAADF) STEM images without affecting the original Z-contrast information. The method can be applied to extract valuable compositional atomic-column data from any HAADF-STEM image of any kind of bulk crystals with local occupancy or chemistry fluctuations, stacking faults, special grain boundaries or interfaces, for which we have an available structural model. After the warping, distortion-corrected images can be further enhanced using conventional image-filtering techniques, and finally quantified with HAADF-STEM image simulations. The applicability of the IMAGE-WARP method was illustrated using experimental HAADF-STEM images of a strontium titanate crystal disrupted with a Ruddlesden-Popper-type antiphase boundary.