Sequence selective hydrolysis of linear DNA using conjugates of Zr(IV) complexes and peptide nucleic acids

A series of conjugates of peptide nucleic acids (PNA) and Zr(IV) complexes was prepared. Their ability to hydrolyze DNA was tested using MALDI-TOF mass spectrometry and HPLC. The most efficient artificial restriction enzyme found, PNA conjugate with Zr(IV) complex of tris(hydroxymethyl)-aminomethane, cleaves DNA targets sequence selectively in close proximity to the Zr(IV) complex. It was demonstrated that cleavage products are substrates of terminal transferase.     

Solid-phase triester synthesis of modified triuridylates using an effective condensing agent

Triuridylates containing 2-deoxyuridine, 5-bromouridine, and 6-azauridine in various positions of the sequence have been synthesized by the use of an O-nucleophilic nucleotide condensation catalyst — 4-ethoxypyridine N-oxide — under the conditions of the solid-phase triester method.Institute of Molecular Biology and Genetics, Ukrainian SSR Academy of Sciences, Kiev. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 416–421, May–June, 1988.     

Surface morphology of silicon single crystals treated with acid polishing etchants

The specific features of formation of micro-and nanorelief on the (001) surface of silicon single crystals upon treatment with widely used etchants HF HNO₃ H₂O and with poorly studied etchants HF KMnO₄ H₂O were studied. The relief of the etched surface was examined by optical, scanning electron, and atomic-force microscopy. The polishing properties of the etchants and the silicon etching rates were studied in relation to the oxidant content. The polishing properties of the etchants were compared by analyzing statistical distribution of such characteristics of the relief of the etched surface as the height and length of micro- and nanowaves.     

Synthesis, Structure and Selective Upper Rim Functionalization of Long Chained Alkoxythiacalix[4]arenes

The synthesis and X-ray structure investigation of the cone shaped monodecyloxythiacalix[4]arene, as well as the introduction of the reactive bromide or chloromethyl groups on it’s upper rim are described. Preparation of the amphiphilic derivative of thiacalixarene bearing three hydrophilic diethoxyphosphoryl groups at the upper rim and lipophilic decyloxy group at the lower rim is presented.     

A convenient synthesis method of 5-oxopyrazolo[4,3-b]pyridine-6-carboxylic acids and their nitriles

Chemistry of Heterocyclic Compounds - N-Boc-protected 5-formyl-1H-pyrazol-4-amines react with malonic acid in pyridine in the presence of pyrrolidine at 45–50°С or with malonic...     

Anisotropic Nucleation,Growth and Ripening under Stirring—A Phenomenological Model

The anisotropic formation of elongated metal-oxide aggregates in water under intensive stirring is analyzed. It is treated in terms of anisotropic ballistically mediated aggregation kinetics in open systems. The basic kinetic equations describing the stages of homogeneous nucleation, independent growth, and ripening of the aggregates are formulated for the open system under the external influence with the stirring intensity as the main parameter governing the process. The most significant elongation of the aggregates is shown to evolve at the ripening stage.     

Kinetics of ethanol decay in mouth‐ and nose‐exhaled breath measured on‐line by selected ion flow tube mass spectrometry following varying doses of alcohol

A study has been carried out of the decay of ethanol in mouth‐exhaled and nose‐exhaled breath of two healthy volunteers following the ingestion of various doses of alcohol at different dilutions in water. Concurrent analyses of sequential single breath exhalations from the two volunteers were carried out using selected ion flow tube mass spectrometry, SIFT‐MS, on‐line and in real time continuously over some 200 min following each alcohol dose by simply switching sampling between the two volunteers. Thus, the time interval between breath exhalations was only a few minutes, and this results in well‐defined decay curves. Inspection of the mouth‐exhaled and nose‐exhaled breath data shows that mouth contamination of ethanol diminished to insignificant levels after a few minutes. The detailed results of the analyses of nose‐exhaled breath show that the peak levels and the decay rates of breath ethanol are dependent on the ethanol dose and the volume of ethanol/water mixture ingested. From these data, both the efficiency of the first‐pass metabolism of ethanol and the indications of gastric emptying rates at the various doses and ingested volumes have been obtained for the two volunteers. Additionally and simultaneously, acetaldehyde, acetic acid and acetone were measured in each single breath exhalation. Acetaldehyde, the primary product of ethanol metabolism, is seen to track the breath ethanol. Acetic acid, a possible secondary product of this metabolism, was detected in the exhaled breath, but was shown to largely originate in the oral cavity. Breath acetone was seen to increase over the long period of measurement due to the depletion of nutrients. Copyright © 2010 John Wiley & Sons, Ltd.     

Influence of Calixarenes on Chromatographic Separation of Benzene or Uracil Derivatives

The addition of calix[4]arenes to MeCN/H₂O or MeOH/MeCN/THF/H₂O mobile phases improves LC separation of benzene or uracil derivatives on Separon SGX C18 or Separon SGX NH₂ supports. Structure of the calixarenes and their host–guest supramolecular complexes with the analytes are discussed in context of the LC separation.     

Use of tin as a surfactant material for the growth of thin silver films on silicon oxide

In this letter, we report on the use of tin as an effective surfactant material for silver growing on silicon oxide. We observed that submonolayers of Sn pre-deposited on SiO₂ result in earlier film coalescence and formation of smoother Ag layers. We suggest that Sn atoms reduce the Ag-adatom mobility resulting in experimentally observed increased island density and decreased film roughness. Angle-resolved X-ray photoelectron spectroscopy reveals that Sn remains under the Ag layer giving circumstantial evidence that at later stages of Ag film growth Sn does not influence the interlayer transport.