Gauge theory of Faddeev-Skyrme functionals

We study geometric variational problems for a class of nonlinear sigma-models in quantum field theory. Mathematically, one needs to minimize an energy functional on homotopy classes of maps from closed 3-manifolds into compact homogeneous spaces G/H. The minimizers are known as Hopfions and exhibit localized knot-like structure. Our main results include proving existence of Hopfions as finite energy Sobolev maps in each (generalized) homotopy class when the target space is a symmetric space. For more general spaces we obtain a weaker result on existence of minimizers in each 2-homotopy class. Our approach is based on representing maps into G/H by equivalence classes of flat connections. The equivalence is given by gauge symmetry on pullbacks of G-->G/H bundles. We work out a gauge calculus for connections under this symmetry, and use it to eliminate non-compactness from the minimization problem by fixing the gauge.Comment: 34 pages, no figure

Synthesis of lipophilic N-phosphorylmethylated amino acids and their membrane-transport properties towards some organic acids

© 2016 Taylor & Francis Group, LLC.One-pot procedureswere developed for the synthesis of lipophilic N-(dialkylphosphorylmethyl) derivatives of natural amino acids with high yields from dioctyloxide, formaldehyde, and an amino acid in the presence of amino acid hydrochloride.Membrane transport properties of the new phosphorylated amino acids towards polyfunctional carboxylic acidswere studied. Itwas found that N,N-bis[(dioctylphosphoryl)methyl]- β-alanine is a selective extractant for glutaric acid

Measurement of AhR Ligands in the Tissues of Colon Cancer Patients with XRE Luciferase Reporter

The Aryl hydrocarbon receptor (AhR) ligands exhibiting modulating activity represents a new class of anticancer agents that can be directed towards several tumors. We have examined AhR expression in human colon cancer and adjacent non-tumor tissue. AhR expression level was about 2-7 times higher in tumor tissue samples than in the adjacent non-tumor samples (in 82% of all the samples). We were unable to find any increase of ABCG2 expression on the level of the transcription, while the expression of MDR2 was increased in half of the tumors compared to the levels of expression in normal adjacent tissue. We have used FICZ as a potent high affinity ligand of the AhR to calibrate the reporter cell line HEK293T-AhR-luc as a potent high affinity ligand of the AhR. The concentration of xenobiotic response element (XRE) ligands is higher, than in the blood of healthy people in 86% of the patients. The proposed test system will allow the use of the AhR ligand level as an additional diagnostic marker in the treatment of colon cancer

Genetic diversity and breeding value of synthetic hexaploid wheat introduced into the VIR collection

For the  successful  development of wheat  breeding in Russia, a genetically  diverse  and  well-characterized starting material, mainly stored  at the VIR collection, is needed. To replenish  the collection, 36 lines (accessions) of synthetic hexaploid  wheat  (SHWs) developed at CIMMYT by crossing Triticum durum with Aegilops tauschii were studied.  Our research  was aimed at studying  the SHWs using a complex of morphological and economically  valuable traits in the environments of European Russia’s northwestern part (E30°, N59°), evaluating the reaction  of the SHWs to a photoperiod  and determining their genetic heterogeneity and similarities by gliadins as biochemical  markers. The results showed that the variability of different traits for SHWs fits into the framework of the genus  Triticum, and so SHWs can be classified as poorly domesticated forms. Their distinctive feature, valuable for wheat  breeding, is a large weight  of a thousand grains (up to 60.6 g). This trait was characterized by a low degree of variability and a low correlation  with other  traits. The reaction  of wheat  plants to the length  of the day is crucial for their transition  from vegetative to reproductive development. The SHWs studied differed from common wheat and one another by responses to the short day and by the length  of the ‘emergence-heading’ phase  if they grew under  the conditions of a long day. The delay in the development of plants with a short photoperiod ranged from 5.4 to 53.8 days. On a long day, the duration of the ‘emergence-heading’ phase  varied from 39.5 to 53.9 days. A possible genetic basis for the differences  identified is discussed.  To assess the diversity of SHWs, we also used  gliadin proteins as informative  biochemical  markers. It was revealed  that 21 SHWs were homogeneous, and the rest, heterogeneous. Forty-four different biotypes were found for the SHWs studied,  from which 36 were unique.  Relationships between biotypes have been  demonstrated using cluster analysis. It should be noted that 13 SHWs were unstable. In each of them, some plants differed from the others  in terms of a complex of morphological characters, reaction to a photoperiod, and gliadin patterns. It is possible that the instability of accessions  is the result of genome rearrangement in SHWs. SHW accessions  and the forms isolated from them are considered as sources of new genetic variability to improve common wheat

D-branes as a Bubbling Calabi-Yau

We prove that the open topological string partition function on a D-brane configuration in a Calabi-Yau manifold X takes the form of a closed topological string partition function on a different Calabi-Yau manifold X_b. This identification shows that the physics of D-branes in an arbitrary background X of topological string theory can be described either by open+closed string theory in X or by closed string theory in X_b. The physical interpretation of the ''bubbling'' Calabi-Yau X_b is as the space obtained by letting the D-branes in X undergo a geometric transition. This implies, in particular, that the partition function of closed topological string theory on certain bubbling Calabi-Yau manifolds are invariants of knots in the three-sphere.Comment: 32 pages; v.2 reference adde

Synthesis of new lipophilic phosphine oxide derivatives of natural amino acids and their membrane transport properties toward carboxylic acids

© 2015 Pleiades Publishing, Ltd. One-pot procedures were developed for the synthesis of lipophilic N-(dialkylphosphorylmethyl) derivatives of natural amino acids with high yields from dioctyl- or didecylphosphine oxide, formaldehyde, and amino acid in the presence of amino acid hydrochloride. The reactions with some amino acids were also effective under catalysis by crown ether. The structure of the isolated N-(dialkylphosphorylmethyl) and N,N-bis(dialkylphosphorylmethyl)amino acids was determined on the basis of 1H, 13C, and 31P NMR and mass spectra; the structure of (S)-N-[(dicyclohexylphosphoryl)methyl]-α-alanine was proved by X-ray analysis, and intermolecular association of its molecules in crystal was characterized. Membrane transport properties of the new phosphorylated amino acids with respect to polyfunctional carboxylic acids were studied, and factors responsible for the efficiency and selectivity of membrane transport of acid substrates were estimated. Selective extraction of glutaric acid through a liquid membrane containing N,N-bis[(dioctylphosphoryl)methyl]-β-alanine was revealed

Synthesis of α-hydroxy(polyprenyl) bisphosphonates

Bisphosphonates derived from natural terpenes were synthesized by phosphonylation of corresponding aldehydes. The general strategy of introduction of the phosphonate groups into the polyprenol molecule involves successive treatment of a hydroxyl compound by Swern reagent to oxidize the C-OH group into C=O and a (EtO)3P/[PyH]+ClO - 4 mixture to phosphylate the resulting carbonyl compound. © 2014 Pleiades Publishing, Ltd

Wilson Loops, Geometric Transitions and Bubbling Calabi-Yau's

Motivated by recent developments in the AdS/CFT correspondence, we provide several alternative bulk descriptions of an arbitrary Wilson loop operator in Chern-Simons theory. Wilson loop operators in Chern-Simons theory can be given a description in terms of a configuration of branes or alternatively anti-branes in the resolved conifold geometry. The representation of the Wilson loop is encoded in the holonomy of the gauge field living on the dual brane configuration. By letting the branes undergo a new type of geometric transition, we argue that each Wilson loop operator can also be described by a bubbling Calabi-Yau geometry, whose topology encodes the representation of the Wilson loop. These Calabi-Yau manifolds provide a novel representation of knot invariants. For the unknot we confirm these identifications to all orders in the genus expansion.Comment: 26 pages; v.2 typos corrected, explanations clarified; v.3 typos corrected, reference adde

Bis(dialkylphosphinylmethyl)alkylamines as the liquid and membrane extractants of rare earth and trace metal ions

A large number of new lipophilic mono- and bisphosphinylamines were synthesized on the basis of the Kabachnik-Fields reaction and extraction and membrane transport properties of the synthesized compounds toward the rare earth and alkaline metal were studied. Aminophosphonyls demonstrate extracting efficiency and selectivity toward Sc(III), In(III), Y(III), and Ga(III) rare earth elements. The mixture of reactants bis(dialkylphosphinylmethyl)alkylamine, and thio- and dithiophosphoric acid shows selectivity toward lithium ions. © 2013 Copyright Taylor and Francis Group, LLC