Interaction of Palladium(II) Acido Complexes with DNA

Interaction of K₂[PdCl₄] (I) and (C₅H₁₂NO)₂[PdCl₄] (II) with DNA in vitro is studied. No fragmentation of DNA occurs under the action of II. The interstrand cross-links are formed due to the formation of complexes with purine and pyrimidine bases; no interaction with DNA phosphates is observed. The cation does not play an essential role in the formation of cross-links.     

Experimental and numerical studies on transmission of gaseous detonation to a less sensitive mixture

A phenomenon of detonation transmission from one gaseous mixture (donor) to another of lower sensitivity (acceptor) was studied experimentally and numerically. The objective was to study effects of a donor mixture length and acceptor mixture sensitivity on the possibility of detonation transmission. Experiments were carried out in detonation tube 9.5–12 m long and 174 mm id. Three types of donor mixtures were used in the driver: stoichiometric acetylene/air, stoichiometric hydrogen/air, and 20% of hydrogen/air. Air mixtures with 14–29.6% of hydrogen were used as acceptors. Driver length varied from 0.17 to 5.6 m. Detonation transmission was studied for an abrupt opening of interface between two mixtures. Series of 1D and 2D calculations were made to simulate the problem numerically. Both, results of experiments and calculations revealed a set of parameters that effect transmission process. Critical conditions were determined as minimum driver length expressed in terms of characteristic chemical reaction length scales of acceptor mixture. They were shown to depend on differences in reaction rates and energy contents of donor and acceptor mixture. Received 6 January 1997 / Accepted 20 March 1997     

Dynamics Equations for an Anisotropic Plastic Subsystem of a Fractal Medium

Model equations for the dynamics of an anisotropic plastic subsystem of a fractal medium are obtained in explicit form using fractional calculus. The slow dynamics of a number of parameters are analyzed and the results are represented graphically.     

Ga penetration into polymers

Received: 31 August 1998 / Accepted: 29 October 1998     

Particle-in-cell plasma simulation on heterogeneous cluster systems

This paper offers an approach to high-performance implementation of the Particle-in-Cell (PIC) algorithm for GPU-enabled heterogeneous cluster systems. We present Picador — a tool for three dimensional plasma simulation based on the fully relativistic PIC algorithm aimed at research of high intensity laser-matter interaction. It scales up to at least 2048 CPU cores with 85% strong scaling efficiency and 512 GPUs with 64% weak scaling efficiency, achieving up to 28% of the peak performance on the CPU and 14% on the GPU, respectively.     

Cationic–anionic palladium complexes: effect of hydrogen bond character on their stability and biological activity

The solution state of palladium cationic–anionic complexes (AmH _n ) _k [PdCl₄] prepared for the first time, where Am is morpholine, methylmorpholine, aminoethylmorpholine, 5-aminovaleric acid, L-1-phenyl-2-methylaminopropanol, and m-xylilenediamine, has been studied by electronic absorption spectroscopy, NMR, and pH measurements. The agreement of obtained results for the state of the complexes in water and NaCl solutions with IR and X-ray diffraction data for these complexes has allowed us to substantiate the principle for designing patent formulation (C₅H₁₂NO)₂[PdCl₄], a new type of palladium complexes, palladium(II) cationic–anionic complexes showing high antitumor and antimetastatic activity. Crystallographic data for six obtained complexes have been presented.     

Study of the packing density and molecular orientation of bimolecular self-assembled monolayers of aromatic and aliphatic organosilanes on silica

Bimolecular self-assembled monolayers (SAMs) of aromatic and aliphatic chlorosilanes were self-assembled onto silica, and their characteristics were established by contact angle measurement, near-edge X-ray absorption fine structure spectroscopy, and Fourier transform infrared spectroscopy. Three aromatic constituents (phenyltrichlorosilane, benzyltrichlorosilane, and phenethyltrichlorosilane) were studied in combination with four aliphatic coadsorbates (butyltrichlorosilane, butyldimethylchlorosilane, octadecyltrichlorosilane, and octadecyldimethylchlorosilane). Our results demonstrate that whereas SAMs made of trichlorinated organosilanes are densely packed, SAMs prepared from monochlorinated species are less dense and poorly ordered. In mixed systems, trichlorinated aromatics and trichlorinated aliphatics formed SAMs with highly tunable compositions; their surfaces were compositionally homogeneous with no large-scale domain separation. The homogeneous nature of the resulting SAM was a consequence of the formation of in-plane siloxane linkages among neighboring molecules. In contrast, when mixing monochlorinated aliphatics with trichlorinated aromatics, molecular segregation occurred. Although the two shortest aromatic species did not display significant changes in orientation upon mixing with aliphatics, the aromatic species with the longest polymethylene spacer, phenethyltrichlorosilane, displayed markedly different orientation behavior in mixtures of short- and long-chain aliphatics.     

Oligomer orientation in vapor-molecular-layer-deposited alkyl-aromatic polyamide films

The surface-limited molecular-layer deposition of alkyl-aromatic polyamide films using sequential doses of 1,4-butane diamine (BDA) and terephthaloyl dichloride (TDC) is characterized using in situ quartz crystal microbalance and ex situ spectroscopy analysis. For the first time, near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is used to offer insight into molecular orientation in films deposited via molecular-layer deposition (MLD). The results show that the oligomer units are lying nearly parallel to the surface, which differs from the linear vertical growth mode often used to illustrate film growth.     

Investigation of the electronic structure of SmCo5 by means of X-ray photoelectron spectroscopy

The signals and signal-to-noise ratios are calculated for Lorentzian and Gaussian inputs to unmodulated electron spectrometers with wide slits and to over-modulated spectrometers. Data which characterise the distortion of the output as compared to the input are given in graphical form. It is concluded that unmodulated spectrometers give a small but useful increase in signal-to-noise ratio for peaks on low backgrounds whilst introducing the least distortion of peak shape.     

Vibrations of a fractal elastic string

We construct the solution of the fractional space-time equations that describe the vibrations of a quasi-one-dimensional fractal elastic string. We give the solution of the Cauchy problem for fractional differential equations with initial conditions. We carry out a numerical analysis and construct the graphic variation of the displacement function of a fractal elastic string. Three figures. Bibliography: 7 titles. Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 26, 1996, pp. 142–147