Synthesis and properties of oxadiazole based V-shaped, shape persistent nematogens

A series of biaxial V-shaped, shape-persistent molecules has been synthesised by stepwise coupling of phenylene ethynylene arms to an oxadiazole bending unit. Studies of their thermotropic nematic phases point to phase biaxiality.     

Cyclic cohomology of certain nuclear Fréchet algebras and DF algebras

We give explicit formulae for the continuous Hochschild and cyclic homology and cohomology of certain \(\hat \otimes\)-algebras. We use well-developed homological techniques together with some niceties of the theory of locally convex spaces to generalize the results known in the case of Banach algebras and their inverse limits to wider classes of topological algebras. To this end we show that, for a continuous morphism ?: x → y of complexes of complete nuclear DF-spaces, the isomorphism of cohomology groups H ⁿ(?): H ⁿ (x) → H ⁿ (y) is automatically topological. The continuous cyclic-type homology and cohomology are described up to topological isomorphism for the following classes of biprojective \(\hat \otimes\)-algebras: the tensor algebra E \(\hat \otimes\) F generated by the duality (E,F,<·,·>) for nuclear Fréchet spaces E and F or for nuclear DF-spaces E and F; nuclear biprojective Köthe algebras λ(P) which are Fréchet spaces or DF-spaces; the algebra of distributions ε^*(G) on a compact Lie group G.     

High power CW (16W) and pulse (145W) laser diodes based on quantum well heterostructures

We suggested and experimentally confirmed the effective method of internal optical loss reduction by high order mode suppression in a separate confinement quantum well laser heterostructure with asymmetric ultra thick waveguide. Manufacturing of InGaAs/GaAs/AlGaAs laser heterostructure with a 1.7 microm-thick asymmetric waveguide allowed attaining super low value of internal optical loss alphai=0.34 cm-1 preserving high efficiency and fundamental transverse mode operation. Record-high 16 W continuous wave (CW) and 145 W pulse room temperature front facet output optical power and 74% wallplug efficiency were attained in 100-microm-aperture 1.06-microm-emitting laser diodes with 3 mm cavity length.     

A new reaction of sulfur ylides. Imination of dimethylsulfonium ketoylides with tosyl isocyanate

Russian Chemical Bulletin -     

Trace enrichment of phenylcarboxylic acids from a model biological fluid and serum of human blood

The study was focused on the development of a solid‐phase extraction protocol for seven phenylcarboxylic acids from albumin solutions by using unmodified hyper‐cross‐linked polystyrene restricted access materials with crosslinking degrees varying from 100 to 400% (four of the acids are known to be markers of sepsis). The breakthrough volume of the most hydrophilic 3,4‐dihydroxybenzoic acid rises as the sorbent bridging extent grows. Inversely, the breakthrough volume of the most hydrophobic 3‐phenylpropionic acid was found to decrease considerably when the degree of crosslinking exceeds 200%. This unusual pattern is because of the superposition of two opposite tendencies. Increasing substitution extent of phenyls facilitates their π‐π‐interactions with polar compounds whereas rising density of the network reduces the accessibility of sorption sites to all solutes. Mini‐cartridges containing 30 mg of an optimal sorbent take up the acids completely and reversibly, the recoveries being close to 100% even in the presence of high concentrations of albumin. By coupling the developed solid‐phase extraction with high‐performance liquid chromatography and diode array detection technique, we managed to determine quantitatively phenylcarboxylic acids in the serum of a healthy patient blood, and the recoveries varied from 93 to 100% while the limit of quantification was (4–9) × 10^?7 M.     

Synthesis and Structure of New <Emphasis Type="Italic">gem</Emphasis>-Diols with 1,2,3-Triazole Fragment

α-(1,2,3-Triazole)-substituted acetals were obtained using the click procedure. Under acid hydrolysis conditions these acetals were converted into earlier unknown stable gem-diols containing a triazole ring.     

Study of the catalytic activity of electrochemically reduced forms of phthalocyanines in the reaction of CO2 with epoxides

Catalytic activity of electrochemically reduced forms of mono- and diphthalocyanine complexes of transition and rare-earth elements in the reaction of carbon dioxide with epoxides is considerably higher than that of corresponding neutral forms. The catalytic efficiency depends on the nature of the phthalocyanine complex, the method of the catalyst immobilization, and the electrophilicity of epoxide. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2205–2213, November, 1998.     

Examples of banach algebras over commutativebanach algebras of given homological dimension

We prove that, for every natural number n, there exists a unital semisimple Banach star algebra Aand a closed star subalgebra Bof the centre of A, different from C, such that the global B-homological dimension and the B-homological bidimension of Aare both equal to n. The algebras Aand Bcan be taken to be function algebras.