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D L Maslov

Publications and source records attributed to D L Maslov.

8 recordsLinked to original sources
PubMed2005

Quantum correction to conductivity close to a ferromagnetic quantum critical point in two dimensions.

We study the temperature dependence of the conductivity due to quantum interference processes for a two-dimensional disordered itinerant electron system close to a ferromagnetic quantum critical point. Near the quantum critical point, the crossover between diffusive and ballistic regimes of quantum interference effects occurs at a temperature T*=1/taugamma(E(F)tau)2, where gamma is the parameter associated with the Landau damping of the spin fluctuations, tau is the impurity scattering time, and E(F) is the Fermi energy. For a generic choice of parameters, T* is smaller than the nominal crossover scale 1/tau. In the ballistic quantum critical regime, the conductivity behaves as T1/3.

Journal Article↗
PubMed2002

Magnetization in the ultraquantum limit.

The magnetization below and far above the quantum limit for small Fermi surface orbits has been measured in the metallic compound LaRhIn(5). The magnetization due to a pocket of Fermi surface that comprises less than 1 part in 10(4) of the total Brillouin zone volume, and for which the quantum limit is approximately 7 T, leads to the appearance of an overall sample magnetic moment at fields between 7 and 32 T. This moment arises from diamagnetic currents produced by electrons in the ultraquantum limit. A model calculation of the origin and magnitude of the effect is in excellent agreement with the measured field dependence of the induced magnetization.

Journal Article↗
PubMed2002

New peptidomimetics of insulin.

New peptidomimetics that have been obtained in the course of our experimental work show distinct insulin-like activity both in vitro and in vivo. The first peptidomimetic (PM 1) is essentially a decapeptide in which sites of A (20-21) and B (19-26) chains of insulin are linked by the peptides bond (Cys-Gly-Glu-Arg-Gly-Phe-Phe-Tyr-Cys-Asn). The second peptidomimetic (PM 2) has similar set of amino acid residues, except that two aromatic amino acids corresponding to the residues of B chain of insulin (B24 and B26) have been replaced with their D optical isomers (Cys-Gly-Glu-Arg-Gly-DPhe-Phe-DTyr-Cys-Asn). The third peptidomimetic (PM 3) has been obtained through acylation of N-terminal of PM 1 by the use of palmitic acid. The peptidomimetic incorporating D aromatic amino acids (PM 2) was demonstrated to exhibit more pronounced hypoglycemic impact, while the acylation of decapeptide tends to prolong the effective time of peptidomimetic influence in vivo.

Animals↗
PubMedDate not supplied

[Specific interaction of liposomes coated by insulin synthetic fragments with PC 12 cells].

The synthesized peptides represent the functionally important site for binding to insulin receptor. Amino acids of peptide I correlate with B-chain of insulin at the position B19-B26 and A-chain at the position A20-A21. Amino acids of peptide II correlate with B-chain of insulin at position B23-B26 and A-chain at the position A20-A21. It was shown, that the these peptides increased liposomal binding followed by receptor-mediated endocytosis by cells PC12.

Animals↗
PubMedDate not supplied

[The prolonged action of an insulin peptidomimetic by the substitution of L-amino acid for its D-isomer].

The synthesized decapeptide represents functionally important site for binding to the insulin receptor. Amino acid residues at position, 1-8 correlate with B-chain of insulin at position B19-B26, and the residues at position 9-10 correlate with A-chain at position A20-A21. The new peptide was obtained by substitution of two aromatic L-amino acid residues (B24 and B26) for their D-optical isomers. These peptides were tested with cell cultures L929 and PC12 (glucose uptake). Increased concentration of peptides correlated with stimulation of glucose uptake by cells. Studies carried out on animals with streptosotocine-caused diabetes showed that, synthesized peptides were able to decrease glucose level in blood, but decapeptide with D amino acid showed a more pronounced effect compared to the decapeptide with L amino acid.

Amino Acid Substitution↗
PubMedDate not supplied

[Hypoglycemic effect of an extract from Aronia melanocarpa leaves].

The action of extract from Aronia melanocarpa leaves to blood glucose level was investigated. It was shown that incorporated into drinking water and administrated intraperitoneally, the extract significantly reduce the blood glucose level of streptozotocin (STZ)-diabetic and normal rats.

Animals↗
PubMedDate not supplied

[Structural and functional characteristics of insulin and mechanism of its effect].

On the basis of analysis of own and literature data on insulin-receptor interaction two centers responsible for receptor binding were identified on 3D-structure of insulin with receptor. Two extracellular domains of insulin receptor interact with these centers on insulin molecule. The comparative analysis of primary structures of the protein disulfide isomerase thioredoxine domains and C-terminal domain of the receptor suggests existence of the thioredoxine domain in the insulin receptor. In this connection the role of the thiol disulfide an exchange reaction is discussed in terms of insulin interaction with receptor followed by subsequent conformational changes in the receptor molecule and activation of the intercellular tyrosine kinase domain. It is supposed, that besides known mechanism of receptor mediated insulin signal transduction and tyrosine kinase activation, there is other mechanism of insulin intracellular signal transduction realised via cytosolic insulin-binding proteins. Major components of intercellular insulin signal transduction include: protein disulfide isomerase and insulin degrading enzyme. The importance of change of the intracellular insulin degradation rate for insulin signal transduction is discussed.

Amino Acid Sequence↗