Radical copolymerization of N-vinylformamide with unsaturated carboxylic acids

Radical precipitative copolymerization of N-vinylformamide with acrylic and methacrylic acids in isopropanol at 60°C, with azobisisobutyric acid dinitrile as initiator, was studied. The conditional values of the relative reactivities were found: r ₁ = 0.068 ± 0.008 and r ₂ = 1.638 ± 0.025 for the N-vinylformamide-methacrylic acid copolymer and r ₁ = 0.15 ± 0.03 and r ₂ = 0.19 ± 0.09 for the N-vinylformamide-acrylic acid copolymer.     

On the composition of copper(II), cobalt(II), and nickel(II) complexes with some 3,6-disubstituted 1,2,4,5-tetrazines

Complex formation in the systems containing copper(II), cobalt(II) and nickel(II) ions (M) and 3-(3,5-dimethylpyrazol-1-yl)-6-R-1,2,4,5-tetrazines (R = 2-hydroxyethylamino, piperidino) (L) was studied by voltammetry and spectrophotometry. Cu(II), Co(II) and Ni(II) were found to form complex compounds with derivatives of 1,2,4,5-tetrazine with the ratio of the components M:L = 1:1. The complex stability constants were determined.     

Hydrodynamic shearing of DNA in a polymeric microfluidic device

With the advent of next-generation sequencing (NGS) systems and the associated high throughput they afford, the input to these machines requires manageable lengths of fragments (~1000 bp) produced from chromosomal DNAs. Therefore, it is critical to develop devices that can shear DNA in a controlled fashion. We report a polymer-based microfluidic device that establishes an efficient and inexpensive platform with performance comparable to a commercially available bench-top system.     

Specific features of the internal photoelectric effect of the Cu(II)/Fe(III) oxalate complex with ethylenediamine in an insulating polymer film

Physics of the Solid State - The electrical and photoconductive properties of films of the composites based on poly(vinyl alcohol) with additions of the (NH4)[Cu(en)2Fe(C2O4)3] · 2DMSO...     

Reconstruction of the distribution pattern for the bloodstream velocity vector in the acoustic tomography procedure

Results of the development of additive-correlation and multiplicative-correlation methods for a tomographic reconstruction of the distribution pattern of the total bloodstream velocity vector with the help of ultrasound are presented for relatively low frequencies (1–2) MHz, which provide a sufficient penetration depth. The reconstruction of the vector field uses a great body of spatial-correlation data and is closely related to the process of constructing the tomographic image of a given organ as a whole. A spatial cross-correlation of intermediate images is used, which makes it possible to estimate the bloodstream velocity vector independently of the value of the real blood transfer within the total measurement time. Results of numerical simulations for constant and varying distributions of the bloodstream velocity vector in the cross sections of blood vessels are presented.     

Synthesis and cytotoxicity of silylalkylthio‐substituted N‐heterocycles and their hydroselenites

New hydroselenites of the different silylalkylthio‐substituted N‐heterocycles have been prepared by the reaction of selenium dioxide with N‐heterocycles in an aqueous medium. Their structure was confirmed by ¹H, ¹³C, and ⁷⁷Se NMR data. Most of these silylalkylthio‐substituted N‐heterocycles and their hydroselenites have an expressed cytotoxic activity on the MG‐22A (mouse hepatoma), HT‐1080 (human fibrosarcoma), B16 (mouse melanoma), and Neuro 2A (mouse neuroblastoma) cell lines. Some of the hydroselenites exhibit free‐radical protection simultaneously with a high cytotoxic effect. The substances studied were also active in vivoagainst sarcoma S‐180. Copyright © 2003 John Wiley & Sons, Ltd.     

Design of Turn-On Near-Infrared Fluorescent Probes for Highly Sensitive and Selective Monitoring of Biopolymers

Simple, sensitive, and selective detection of specific biopolymers is critical in a broad range of biomedical and technological areas. We present a design of turn-on near-infrared (NIR) fluorescent probes with intrinsically high signal-to-background ratio. The fluorescent signal generation mechanism is based on the aggregation/de-aggregation of phthalocyanine chromophores controlled by selective binding of small-molecule “anchor” groups to a specific binding site of a target biopolymer. As a proof-of-concept, we demonstrate a design of a sensor for EGFR tyrosine kinase—an important target in cancer research. The universality of the fluorescent signal generation mechanism, as well as the dependence of the response selectivity on the choice of the small-molecule “anchor” group, make it possible to use this approach to design reliable turn-on NIR fluorescent sensors for detecting specific protein targets present in the low-nanomolar concentration range.     

Carbamoylmethylphosphoryl Compounds: Ch-Acidity and Basicity

Abstract

Carbamoylmethylphosphoryl compounds (CMP) are used as neutral bifunctional extractants. However, little is known about acid-base properties of these compounds. We have studied CH-acidity and basicity of selected CMP, RR′P(O)CH₂C(O)NEt₂ with R,R′ = Alk, Alk₂N, Ar, AlkO, and also H-complexes of CMP with HNO₃.