Synthesis of cytotoxic cyanobactin,Wewakazole B

We report herein the synthesis of cytotoxic cyanobactin, Wewakazole B through an efficient solution-phase approach. The key steps of the synthesis are the macrocyclic lactamization of linear dodecapeptide and construction of two hexapeptides with three different substituted oxazole rings.     

Novel surface tension isotherm for surfactants based on local density functional theory

In this Letter we report a new general method for calculating of surface tension isotherms in the presence of surfactants, based on a local density functional. We illustrate this method by deriving the interfacial tension isotherm for nonionic surfactants at an air-water or oil-water interface by using the self-consistent field theory of polymer brushes. We consider a particular case of local density functional to calculate explicitly how the interfacial tension and the surfactant adsorption depend on the surfactant bulk concentration. Experimental data for the surface tension and the surfactant adsorption isotherm for nonionic surfactants were interpreted with the help of the new isotherm. Very good agreement between the adsorption of n-dodecyl pentaoxyethylene glycol ether (C12E5) at an air-water interface, calculated from the surface tension isotherm and small-angle neutron-scattering is obtained.     

Dipole excitations in 122Te, 126Te and 130Te

Excited states of the nuclei ¹²²Te, ¹²⁶Te and ¹³⁰Te were populated via the (γ, γ') reaction at endpoint energies of the bremsstrahlung between 4.5 and 5.5 MeV. Gamma rays were detected with a EUROBALL-CLUSTER detector and a single detector. In all nuclei several dipole transitions were identified at energies around 3 MeV. The lowest corresponding J = 1 states are interpreted as two-phonon excitations. Quasiparticle-phonon-model calculations predict one 1^? state arising from the coupling of the first quadrupole and the first octupole phonon and one 1⁺ state arising from the coupling of the first and the isovector second quadrupole phonon at about 3 MeV. The calculated transition strengths are compatible with experimental ones.     

A study of an elastomeric coating based on EPDM of cold vulcanization

Studies of the thermostability of vulcanizates of ethylene–propylene–diene rubbers (EPDM) obtained by using dinitrosogenerating systems of low-temperature vulcanization are performed. It is shown that vulcanizates retain sufficient high properties in operation up to 200°C for a long time. The use of such compositions for producing thin rubber coatings applied on a number of insulating materials allows the effect of energy saving to be obtained.     

The effect of aminoalkoxy and glycidoxyalkoxy silanes on adhesion characteristics of double and triple copolymers of ethylene

The effect of aminoalkoxy and glycidoxyalkoxy silanes on strength of a polyethylene-modified copolymer-metal (polyethylene terephthalate) adhesion joint was studied for double and triple acetate copolymers of ethylene. It was shown that such modification resulted in an essential increase in the deformation-strength and adhesion characteristics of adhesive joints.     

Adhesive properties of binary mixtures of some ethylene copolymers

It is shown using the example of polyolefin thermoplasts that the value of adhesion strength is determined by the mechanical properties of a composition.     

Acid-Base Interactions at the Modified Polyethylene-Metal Interface

The acidity parameters of metal and polymeric surfaces were determined as influenced by the extent of surface oxidation of metals and by the modifier content in the polymer.     

Shell-driven magnetic stability in core-shell nanoparticles

The magnetic properties of ferromagnetic-antiferromagnetic Co-CoO core-shell nanoparticles are investigated as a function of the in-plane coverage density from 3.5% to 15%. The superparamagnetic blocking temperature, the coercivity, and the bias field radically increase with increasing coverage. This behavior cannot be attributed to the overall interactions between cores. Rather, it can be semiquantitatively understood by assuming that the shells of isolated core-shell nanoparticles have strongly degraded magnetic properties, which are rapidly recovered as nanoparticles come into contact.     

Lens rigidity in scattering by non-trapping obstacles

We prove that if two non-trapping obstacles in \(\mathbb {R}^n\) satisfy some rather weak non-degeneracy conditions and the scattering rays in their exteriors have (almost) the same travelling times or (almost) the same scattering length spectrum, then they coincide.