Conformational and hydrodynamic properties of the homopolymer of 2-deoxy-2-methacrylamido-D-glucose and its copolymers with acrylic acid and methacrylic acid

Hydrodynamic properties of the homologous series of the homopolymer 2-deoxy-2-methacryla-mido-D-glucose and the copolymers of 2-deoxy-2-methacrylamido-D-glucose with unsaturated acids in 0.2 M NaCl are studied via static and dynamic light scattering, viscometry, refractometry, and translational diffusion. The copolymers synthesized via the free-radical copolymerization of 2-deoxy-2-methacrylamido-D-glucose with acrylic acid or methacrylic acid contain ～20 mol % acid units. At this amount of acid units, the equilibrium rigidity of copolymer chains corresponds to that of homopolymer chains. The copolymers are distinguished by the hydrodynamic characteristics of molecules. The copolymer with methacrylic acid is similar to the homopolymer, whereas the copolymer with acrylic acid features substantially different parameters of relationships relating the hydrodynamic characteristics of homologs to their molecular masses.     

Doping dependence of irreversibility line in Y1−xCaxBa2Cu3O7−δ

The irreversibility lines (IL) for series of Y_1?xCa_xBa₂Cu₃O_7?δ (x = 0.025; 0.10 and 0.20) polycrystalline samples with different overdoping were investigated. The irreversibility fields were determined from measurements of third harmonics AC susceptibility as a function of DC field at constant temperature. For the weakly overdoped sample (with x = 0.025) H_irr(77 K) is about 7 T, which is higher than the previously reported for the non-substituted one. The irreversibility line behavior is typical for glass–liquid phase transition and this is confirmed by transport measurements. On increasing the overdoping the irreversibility fields were shifted towards lower temperatures. The behavior of H_irr(T) for the highly overdoped sample (with x = 0.20) is influenced by the surface barrier effect. It is supposed that in highly overdoped specimen the process of phase separation is enhanced and the Fermi clusters grow in size. This leads to a suppression of the bulk pinning and to a domination of the surface barrier effects and flux creep as well. As a confirmation, the obtained quadratic J_c(T) dependences were presented demonstrating the existence of S–N–S type inter-grain joints in the highly overdoped samples.     

Lipids of the seeds of Cynoglossum officinale

The compositions of the lipids and fatty acids of the seeds ofCynoglossum officinale, familyBoraginaceae have been established. The bulk of the lipids consisted of netural compounds (95.2%), while the amounts of glycolipids and phospholipids were 3.1 and 1.7%, respectively. Among the fatty acids, in addition to the usual components, acids characteristic for theBoraginaceae family have been found: 18:3 (6, 9, 12), 18:3 (9, 12, 15), 18:4 (6, 9, 12, 15), 20:1 (11), 22:1 (13), and 24:1 (15). Institute of the Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. South Urals Reservation, Bashkir. Institute of Chemistry, Bashkir Scientific-Center, Urals Branch, Russian Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 758–762, November–December, 1991.     

Tryptic hydrolysis of inorcanic pyrophosphate modified by phosphate and O-phosphoethanolamine

By the peptide map method, a phosphorylated peptide has been isolated from a tryptic hydrolysate of phosphorylated yeast inorganic pyrophosphatase (I), and this is a direct proof of the formation of a covalent bond between (I) and phosphate in the course of this reaction. The isolation and analysis of the peptide from the tryptic hydrolysate shows that the phosphate acceptor is probably the aspartic acid residue 240 or 248. Analysis of a tryptic hydrolysate of (I) modified with O-phosphoethanolamine has shown that O-phosphoethanolamine forms an amide bond with the carboxy group of the same aspartic acid residue. In an alkaline medium, the phosphate residue migrates to the imidazole ring of a histidine residue, apparently that present in position 222.     

Bernstein-Type Theorems and Uniqueness Theorems

Let be an entire function of finite type with respect to finite order and let be a subset of an open cone in a certain n-dimensional subspace (the smaller , the sparser ). We assume that this cone contains a ray 0} \right\}$$ " align="middle" border="0"> . It is shown that the radial indicator of at any point may be evaluated in terms of function values at points of the discrete subset . Moreover, if tends to zero fast enough as over , then this function vanishes identically. To prove these results, a special approximation technique is developed. In the last part of the paper, it is proved that, under certain conditions on and , which are close to exact conditions, the function bounded on is bounded on the ray.     

Modeling of the Process of Inkjet Printing of Low-Viscosity Liquids

Russian Physics Journal - An approach to inkjet printing of low-viscosity liquids is suggested consisting in suppression of undesirable weakly damped acoustic oscillations under the action of a...     

Chemistry of polyenic and polyacetylenic compounds Communication 12. Hydration of tertiary diacetylenic alcohols and glycols

Summary A study was made of the hydration of tertiary diacetylenic glycols under the action of aqueous dimethylamine solution, which leads to substituted 3(2H)-furanones. Under the conditions of acid hydration, 2-methyl-3,5-hexadiyn2-ol also gives the corresponding furanone.