Electrospun microfibrous poly(styrene-alt-maleic anhydride)/poly(styrene-co-maleic anhydride) mats tailored for enzymatic remediation of waters polluted by endocrine disruptors

Novel bicomponent microfibrous mats containing targeted amount of reactive maleic anhydride groups were prepared by electrospinning of mixed solutions of poly(styrene-alt-maleic anhydride) and poly(styrene-co-maleic anhydride). Then, amino-functionalized P(St-alt-MA)/P(St-co-MA) mats were obtained by reaction with p-phenylenediamine. ATR-FTIR and XPS spectroscopy were used to characterize pristine and modified P(St-alt-MA)/P(St-co-MA) mats. On the next step, laccase from Trametes versicolor was covalently attached onto the modified mats; the average amount of immobilized enzyme was 40 ± 0.7 mg/g mat. The catalytic activity of the immobilized enzyme was studied in respect to bisphenol A (BPA) endocrine disruptor. The optimum activity of the immobilized enzyme was reached at maximum flow rate of 1.3 mL/s. After 90 min the BPA concentration was reduced by 60% and the catalytic activity of microfibrous mats remained stable for about 30 successive reuses. In addition, the relative activity of laccase immobilized on the microfibrous mats was displayed in a broader pH range as compared to that of the free one.     

Cationic polymerization initiated by intercalation compounds of lewis acids. II. Initiating ability and mechanism of action of the initiators

The initiating ability of the graphite intercalation compounds (GICs) of SbCl₅, FeCl₃, and AlBr₃ was investigated. It was found that GICs were able to initiate the polymerization of monomers of different types–cyclosiloxanes, 1,2-epoxides, vinyl ethers, lactones, and vinyl monomers. GICs of SbCl₅ initiated also the polymerization of tetrahydrofuran. The interaction of the monomers (with the exception of the lactones) caused a size increase of the GICs and deformations in their lamellar structure. Relatively high-molecular poly(vinyl ethers) and polydimethylcyclosiloxanes were obtained. The mechanism of action of GICs was discussed.     

Legendre integrators, post-processing and quasiequilibrium

A toolbox for the development and reduction of the dynamical models of nonequilibrium systems is presented. The main components of this toolbox are: Legendre integrators, dynamical post-processing, and the thermodynamic projector. The thermodynamic projector is the tool to transform almost any anzatz to a thermodynamically consistent model. The post-processing is the cheapest way to improve the solution obtained by the Legendre integrators. Legendre integrators give the opportunity to solve linear equations instead of nonlinear ones for quasiequilibrium (“maximum entropy”, MaxEnt) approximations. The essentially new element of this toolbox, the method of thermodynamic projector, is demonstrated on application to the FENE-P model of polymer kinetic theory. The multi-peak model of polymer dynamics is developed.     

Pair covering designs with block size 5

In this article we look at pair covering designs with a block size of 5 and . The number of blocks in a minimum covering design is known as the covering number C(v,5,2). For v?24, these values are known, and all but v=8 exceed the Schönheim bound, L(v,5,2)=⌈v/5⌈(v-1)/4⌉⌉. However, for all v?28 with , it seems probable that C(v,5,2)=L(v,5,2). We establish this for all but 17 possible exceptional values lying in the range 40?v?280.     

Virasoro Versus Superintegrability. Gaussian Hermitian Model

JETP Letters - Relation between the Virasoro constraints and KP integrability (determinant formulas) for matrix models is a lasting mystery. We elaborate on the claim that the situation is improved...     

Discovery of New Ginsenol-Like Compounds with High Antiviral Activity

A number of framework amides with a ginsenol backbone have been synthesized using the Ritter reaction. We named the acetamide as Ginsamide. A method was developed for the synthesis of the corresponding amine and thioacetamide. The new compounds revealed a high activity against H1N1 influenza, which was confirmed using an animal model. Biological experiments were performed to determine the mechanism of action of the new agents, a ginsamide-resistant strain of influenza virus was obtained, and the pathogenicity of the resistant strain and the control strain was studied. It was shown that the emergence of resistance to Ginsamide was accompanied by a reduction in the pathogenicity of the influenza virus.     

The influence of tartaric acid on the growth kinetics of silver single crystals

The influence of tartaric acid (TA) on both the growth kinetics and morphology of silver single crystals was investigated in situ during electrocrystallization. Using laser interferometry the dependence of the monoatomic step velocity vs. overvoltage at different concentrations of TA was studied. Measuring the normal growth rate R we calculated the current on the front crystal face. It is shown that the addition of TA changes its value in complicated way vs. overvoltage.     

Four New Stilbene Oligomers in the Root of Gnetum gnemon

Four new stilbene oligomers, gnemonols G, H, I, and J ( 1 – 4 ), were isolated from acetone extract of the root of Gnetum gnemon along with five known stilbenoids, ampelopsin E, cis‐ampelopsin E, gnetins C, D, and E. The structures were elucidated on the basis of spectroscopic evidence.