Coarse-grained Description of Polymer Blends as Interacting Soft-Colloidal Particles

We present a theoretical approach which maps polymer blends onto mixtures of soft-colloidal particles. The analytical mesoscale pair distribution functions reproduce well data from united atom molecular dynamics simulations of polyolefin mixtures without fitting parameters. The theory exactly recovers the analytical expressions for density and concentration fluctuation structure factors of soft colloidal mixtures (liquid alloys).Comment: 27 REVTex4 pages, 8 PostScript figures, 1 table accepted for publication in Journal of Chemical Physic

Adiabatic creation of entangled states by a bichromatic field designed from the topology of the dressed eigenenergies

Preparation of entangled pairs of coupled two-state systems driven by a bichromatic external field is studied. We use a system of two coupled spin-1/2 that can be translated into a three-state ladder model whose intermediate state represents the entangled state. We show that this entangled state can be prepared in a robust way with appropriate fields. Their frequencies and envelopes are derived from the topological properties of the model.Comment: 10 pages, 9 figure

Chaos assisted adiabatic passage

We study the exact dynamics underlying stimulated Raman adiabatic passage (STIRAP) for a particle in a multi-level anharmonic system (the infinite square-well) driven by two sequential laser pulses, each with constant carrier frequency. In phase space regions where the laser pulses create chaos, the particle can be transferred coherently into energy states different from those predicted by traditional STIRAP. It appears that a transition to chaos can provide a new tool to control the outcome of STIRAP

Peculiarities of polyneuropathy in the peripheral t-cell lymphoma with cytostatics

This paper presents data on the occurrence and form of polyneuropathy in the peripheral T-cell lymphoma, and its main pathogenesis elements. Here the toxic effects of cytotoxic drugs and their role in the impairment of the nervous system have been describe

Algal and cyanobacterial diversity in saline rivers of the Elton Lake Basin (Russia) studied via light microscopy and next-generation sequencing

Naturally saline rivers are known in various regions of the world. Saline rivers with a salinity gradient from the source to the mouth are particularly interesting, because the range of salinity is the structure-forming factor of the hydrobiont assemblage. Such rivers are represented by saline rivers of the Elton Lake Basin in Volgograd region of Russia (the Bolshaya Samoroda River and the Malaya Samoroda River). Herein, we analyzed taxonomic structure and species diversity of microalgae and Cyanobacteria of the saline rivers flowing into the Elton Lake by light microscopy and next-generation sequencing. The differences and possible causes of inconsistencies in the results obtained by these methods are discussed. In total, 91 taxa of microorganisms were identified by integrated approach in the assemblages of microalgae and Cyanobacteria in the middle course of the Bolshaya Samoroda River, and 60 taxa – in the river mouth. The species diversity of those assemblages in the hypersaline Malaya Samoroda River was lower: 27 taxa from the middle course and 23 taxa from the mouth. Next-generation sequencing allowed us to refine and expand the list of microalgae taxa in the studied saline rivers due to detection of species which were hard to identify, low-abundance taxa, as well as extremely small-cell forms. Some discrepancies between the data obtained by light microscopy and next-generation sequencing indicate the advantage of simultaneous use of both methods for study of the algae communities. Such a comprehensive approach provides the most accurate and correct list of taxa added with the morphological descriptions and 18S rRNA and 16S rRNA partial sequences. Generally, 18 taxa have been recorded for the first time in the Bolshaya Samoroda River, belonging to the phyla Chlorophyta (Borodinellopsis sp., Chlorochytrium lemnae Cohn, Caespitella sp., Halochlorococcum sp., Tetraselmis cordiformis (H. J. Carter) F. Stein), Ochrophyta (Pseudocharaciopsis ovalis (Chodat) D. J. Hibberd, Characiopsis sp., Poterioochromonas stipitata Scherffel, Chrysolepidomonas sp.), Euglenozoa (Euglena bucharica I. Kisselev, Lepocinclis tripteris (Dujardin) B. Marin & Melkonian, Phacus orbicularis K. Hübner, P. parvulus G. A. Klebs), Cryptophyta (Hemiselmis cryptochromatica C. E. Lane & J. M. Archibald, Rhodomonas sp., Hanusia phi J. A. Deane), Haptophyta (Pavlova sp.), Cyanobacteria (Johanseninema constrictum (Szafer) Hasler, Dvorák & Poulícková). Seven taxa have been detected for the first time in the algal and cyanobacterial assemblages of the Malaya Samoroda River from the phyla Chlorophyta (Tetraselmis cordiformis, T. arnoldii (Proschkina-Lavrenko) R. E. Norris, Hori & Chihara, T. tetrathele (West) Butcher, Pyrobotrys elongatus Korshikov), Cryptophyta (Hanusia phi), and Cyanobacteria (Synechococcus elongatus (Nägeli) Nägeli, Oscillatoria simplicissima Gomont)

Spoilage at the thermoforming of layered materials

Steady growth of plastics industry necessitates the disposal of waste products from them. More and more manufacturers seek to include recycled materials and their technological waste in polimers compositions. Blending polymeric materials commonly used in the preparation of thermoformed articles from sheets of thermoplastics. Thermoforming process is cost effective, as it requires a significant investment in tooling in the manufacture of small batches of parts. In this study we investigated species discard practical use products, namely bath made by a combination of methods of thermoforming and contact molding coextruded sheets of ABS plastic with polymethylmethacrylate. Results of the study showed the veracity of the submitted samples assumption that as a raw material in the manufacture of sheets usedrecycled materials, which led to marriage in the finished product

POTENTIAL OF COMPUTED TOMOGRAPHY IN THE DIAGNOSTICS OF THE LACRIMAL GLAND EPITHELIAL TUMORS

Objective. Discussion of the X-ray data in patients with epithelial tumors of the lacrimal gland.Material and methods. We examined CT scans of 20 patients with  lacrimal gland epithelial tumors (20 orbits). Pleomorphic adenoma  was diagnosed in 9 patients, pleomorphic adenocarcinoma was  diagnosed in 11 patients. The computed tomogtaphy was performed  according to the standard method with obtaining axial and frontal  slices. The slicethickness was 1.0 mm, sliceinterval – 1.0 mm.Results. The article presents data on the structure of lacrimal gland  epithelial tumors, considering their volume, dimension and density.  Based on the investigation results, the criteria for the differential diagnosis between pleomorphic adenoma and  adenocarcinoma have been established.Conclusion. Computed tomography is an essential diagnostic technique for a suspected lacrimal gland tumor.  Pleomorphic adenocarcinoma is characterized by a greater density  and more heterogeneous structure compared to pleomorphic  adenoma. Nearly 3/4 of patients with pleomorphic adenocarcinoma  present changes in their orbital walls. The pleomorphic adenoma  can’t be ruled out in patients with the thinning of the orbital wall

Theory of spin diffusion in liquid-phase polymer systems

A general theory of spin diffusion in condensed media is constructed by the method of Zwanzig-Mori projection operators using the superpositional approximation to decouple the many-particle correlation functions. The spin diffusion coefficient is expressed in the form Dsp =Dtf+Df, where Dtr. is the contribution associated with translational displacements of the molecules and Df is the contribution caused by intermolecular flip-flop processes. The expression for Dtr differs from the well-known Kubo-Green formula for the self-diffusion coefficient Dsd in that the integrand contains an additional factor Pf(t), which is the probability of the molecular spins not participating in intermolecular flip-flop transitions over the time t. A microscopic expression is obtained for Df in the form of a time integral of the intermolecular dipole-dipole dynamic correlation functions. For liquid-phase polymer system with fairly high molecular mass the condition Dsp≫Dsd is satisfied. © 1998 American Institute of Physics