Bi‐Enzyme Sensor for Phenolic Compounds with Fluorescent Read‐Out

In this paper, the use of tyrosinase (Ty) from Streptomyces antibioticus, labeled with a fluorescent tag, in combination with soluble quinoprotein (PQQ‐containing) glucose dehydrogenase (s‐GDH) to measure trace amounts of phenols is explored. Proof of concept is provided by a series of experiments, which show a clear quantitative dependence of the response on the phenol concentration. One of the advantages of the detection system is that apart from a standard fluorimeter no further instrumentation is required.     

Uniform Stability of Local Extrema of an Integral Curve of an ODE of Second Order

A second-order equation can have singular sets of first and second type, S₁ and S₂ (see the introduction), where the integral curve x(y) does not exist in the ordinary sense but where it can be extended by using the first integral [1–-5]. Denote by Y the Cartesian axis y=0. If the function x(y) has a derivative at a point of local extremum of this function, then this point belongs to S ₁∪Y. The extrema at which y'(x) does not exist can be placed on S ₂. In [5–-8], the stability and instability of extrema on S ₁∪ S ₂ under small perturbations of the equation were considered, and the stability of the mutual arrangement of the maxima and minima of x(y) on the singular set was studied (locally as a rule, i.e., in small neighborhoods of singular points). In the present paper, sufficient conditions for the preservation of type of a local extremum on the finite part of S ₁ or S ₂ are found for the case in which the perturbation on all of this part does not exceed some explicitly indicated quantity which is the same on the entire singular set.     

Genomic salmon testes DNA as a catalyst for Michael reactions in water

The DNA molecule, recognized as the carrier of genetic information in vivo, can function as an efficient organocatalyst for Michael additions of 1,3-dicarbonyl compounds to activated alkenes in aqueous media. The procedure described here is environmentally benign and offers several advantages in terms of simplicity, generality and efficiency. We have used fluorescence spectroscopy to evaluate the catalytic activity of a molecule of DNA.     

Extremal Points of Integral Curves of Second-Order Ordinary Differential Equations and Their Local Stability

In [1--3] an extension of the solution of the equation , to the singular set , is defined in terms of the first integral. In this case all stationary points and all local extrema of the integral curve such that the function has a derivative at the extreme point belong to a set , where Y is the line . We study the local stability of local extrema of different types in the families of equations small enough. Introduce the notation . By abuse of language, we talk about the stability of local extrema when S is replaced with . Some sufficient conditions for stability and instability are found.     

Some qualitative properties of the Van der Pol equation inferred from its singular set

It is shown that the singular set of an extended “inverse” integral curve x(y) of the Van der Pol equation is covered with local extrema of x(y) that are stable with respect to small perturbations in the equation. As a consequence, the qualitative behavior of x(y) can be determined and some of its important properties can be understood.     

Phosphido pincer complexes of platinum: synthesis, structure and reactivity

A series of platinum(II) complexes supported by the tridentate bis(phosphine)phosphido ligand bis(2-diisopropylphosphinophenyl)phosphide) [(i)Pr-PPP] have been synthesized and characterized (1-4). X-Ray structural studies of [(i)Pr-PPP]PtCl (1) and [(i)Pr-PPP]PtCH(3) (3) complexes show meridional [(i)Pr-PPP] ligands around approximately square-planar platinum centers. Structural data and NMR analysis highlight a strong trans influence for the phosphido phosphorous donor, comparable to that of the anionic aryl carbon of the classic PCP pincer complexes. A series of thermally stable [PPP]Pt(IV) compounds, including [PPP]Pt(CH(3))(2)X [X = I (5) and SbF(6) (6)], were also synthesized. The study of the binding affinity of SO(2) and NO to complex 1 has also been addressed.