Dynamic NMR under nonstationary conditions: Theoretical model, numerical calculation, and potential of application.

An expression has been derived for the time dependence of the NMR line shape for systems with multi-site chemical exchange in the absence of spin-spin coupling, in a zero saturation limit. The dynamics of variation of the NMR line shape with time is considered in detail for the case of two-site chemical exchange. Mathematical programs have been designed for numerical simulation of the NMR spectra of chemical exchange systems. The analytical expressions obtained are useful for NMR line shape simulations for systems with photoinduced chemical exchange.

[The ambulatory polyclinic institutions in closed administrative territorial municipality].

The article presents the results characterizing functioning of ambulatory polyclinic institutions included into medical sanitary unit of closed administrative territorial municipality of lesser towns. The study established the resource support of staff and full-time positions of physician and paramedical personnel, dynamics of indicators from 2005 to 2013, coverage of population of able-bodied age with preventive and target medical examinations for syphilis and tuberculosis. The progression of contingents under dispensary registration was determined.

[Preclinical investigation of pharmaceuticals impact against cytochrome P450 activity and prognosis of substrate affinity as means for providing substrate therapy safety].

Tricyclic antidepressants, not influencing the P450 3A4 activity, are safe in combination with drugs of other groups used in the treatment of comorbid patients. Azaphen is is one of the agents most widely used in the clinical practice. The in vitro electrochemical analysis showed that pipofezin (azaphen) was not a substrate, inductor, and/or inhibitor of cytochrome P450 CYP3A4 isoenzymes. The Guzar programme computer modelling and the literature data demonstrated the substrate affinity of pipifezin to CYP1A2.

The structure of mixed H2O-OH monolayer films on Ru(0001).

Scanning tunneling microscopy (STM) and x-ray absorption spectroscopy (XAS) have been used to study the structures produced by water on Ru(0001) at temperatures above 140 K. It was found that while undissociated water layers are metastable below 140 K, heating above this temperature produces drastic transformations, whereby a fraction of the water molecules partially dissociate and form mixed H(2)O-OH structures. X-ray photoelectron spectroscopy and XAS revealed the presence of hydroxyl groups with their O-H bond essentially parallel to the surface. STM images show that the mixed H(2)O-OH structures consist of long narrow stripes aligned with the three crystallographic directions perpendicular to the close-packed atomic rows of the Ru(0001) substrate. The internal structure of the stripes is a honeycomb network of H-bonded water and hydroxyl species. We found that the metastable low temperature molecular phase can also be converted to a mixed H(2)O-OH phase through excitation by the tunneling electrons when their energy is 0.5 eV or higher above the Fermi level. Structural models based on the STM images were used for density functional theory optimizations of the stripe geometry. The optimized geometry was then utilized to calculate STM images for comparison with the experiment.

[Phylogenetic analysis of the family of p53].

A relationship between the functional significance of individual amino acid residues of the p53 protein, their positions in the protein structure, and the mode of evolution of the codons corresponding to these residues has been established. A phylogenetic analysis of the coding sequences of the gene of p53 from 32 vertebrate species has been performed. It was found that those codons undergo selection that affect the efficiency of binding of protein p53 as a transcription factor. It was shown that the frequency of occurrence of generative mutations maintaining the normal function of the protein in conservative codons differs statistically significantly from the frequency of occurrence in the same codons of mutations with the effects of loss and acquisition of the function, and the negatively dominant effect. The phylogenetic analysis and molecular dynamics modeling made it possible to obtain evidence for the functional significance of the G245 residue for which the appearance of the binding site for Zn2+ in the case of the substitution G245G has previously been proposed.

Diffusion and pair interactions of CO molecules on Pd(111).

The diffusion and interactions of CO molecules on Pd(111) were studied by scanning tunneling microscopy. By following the random walk motion of individual molecules as a function of temperature, an activation energy barrier for diffusion of 118 +/- 5 meV was determined. The interaction between CO molecules was found to be repulsive for pairs separated by one or two Pd(111) lattice distances, and weakly attractive at a separation of sqrt[3].

Novel water overlayer growth on Pd(111) characterized with scanning tunneling microscopy and density functional theory.

Scanning tunneling microscopy (STM) images of water submonolayers on Pd(111) reveal quasiperiodic and isolated adclusters with internal structure that would ordinarily be ascribed to icelike puckered hexagonal units. However, density functional theory and STM simulations contradict this conventional picture, showing instead that the water adlayers are composed mainly of flat-lying molecules arranged in planar water hexagons. A new rule for two dimensional (2D) water growth is offered that generates the structures observed experimentally from planar hexamer units.

Dissociative hydrogen adsorption on palladium requires aggregates of three or more vacancies.

During reaction, a catalyst surface usually interacts with a constantly fluctuating mix of reactants, products, 'spectators' that do not participate in the reaction, and species that either promote or inhibit the activity of the catalyst. How molecules adsorb and dissociate under such dynamic conditions is often poorly understood. For example, the dissociative adsorption of the diatomic molecule H2--a central step in many industrially important catalytic processes--is generally assumed to require at least two adjacent and empty atomic adsorption sites (or vacancies). The creation of active sites for H2 dissociation will thus involve the formation of individual vacancies and their subsequent diffusion and aggregation, with the coupling between these events determining the activity of the catalyst surface. But even though active sites are the central component of most reaction models, the processes controlling their formation, and hence the activity of a catalyst surface, have never been captured experimentally. Here we report scanning tunnelling microscopy observations of the transient formation of active sites for the dissociative adsorption of H2 molecules on a palladium (111) surface. We find, contrary to conventional thinking, that two-vacancy sites seem inactive, and that aggregates of three or more hydrogen vacancies are required for efficient H2 dissociation.

Water diffusion and clustering on Pd(111).

The adsorption, diffusion, and clustering of water molecules on a Pd(111) surface were studied by scanning tunneling microscopy. At 40 kelvin, low-coverage water adsorbs in the form of isolated molecules, which diffuse by hopping to nearest neighbor sites. Upon collision, they form first dimers, then trimers, tetramers, and so on. The mobility of these species increased by several orders of magnitude when dimers, trimers, and tetramers formed, and decreased again when the cluster contained five or more molecules. Cyclic hexamers were found to be particularly stable. They grow with further exposure to form a commensurate hexagonal honeycomb structure relative to the Pd(111) substrate. These observations illustrate the change in relative strength between intermolecular hydrogen bonds and molecule-substrate bonds as a function of water cluster size, the key property that determines the wetting properties of materials.

[Comparative clinical, X-ray, and immunogenetic characteristics of respiratory tuberculosis actively detected in risk groups and in individuals turning for medical help]. / Sravnitel'naia kliniko-rentgenologicheskaia i immunogeneticheskaia kharakteristika tuberkuleza organov dykhaniia, aktivno vyiavlennogo v gruppakh riska i u lits, obratibshikhsia za meditsinskoi pomoshch'iu.

Clinical, X-ray, and immunogenetic parameters were comparatively assessed in two groups of first identified patients diagnosed at annual fluorographic studies in groups at risk for tuberculosis and in individuals visiting general health care facilities for symptoms of inflammatory bronchopulmonary disease. Great differences were established in the clinical and X-ray manifestations, the course of the disease, and the patients' immunogenetic status in these groups. Tuberculosis in the patients identified on their referral to general health care facilities is characterized by more severe clinical manifestations, a greater spread of inflammatory and destructive changes in the lung, and massive bacterial isolation. There were certain associations of the HLA antigens A2 and A 11 as markers indicative of tuberculosis resistance with the antigens B35 and Cw4 suggestive of predisposition to tuberculosis in patients with chronic bronchitis.

[The transformation of acute viral hepatitis B into chronic]. / Transformatsiia ostrogo virusnogo gepatita B v khronicheskii.

500 patients with hepatitis B have been followed up from the acute onset to long-term outcome. As for chronic transformation of the disease, at higher risk are patients with mild form, progredient run and inadequate immune response. Of the highest value for identification and prognostication was a dynamic quantitative control over the system HBeAg-anti-HBe providing separate prognosis of establishment of replicative or integrative variants of chronic hepatitis B. In progredient infection an early administration of reaferon in combination with thymogen is thought valid which in many patients is sufficient to prevent the disease transformation into a chronic form.

[Control over the viral DNA level of patients with hepatitis B in the prognosis of its chronicity]. / Kontrol' za soderzhaniem virusnoi DNK u bol'nykh ostrym gepatitom B v prognozirovanii khronizatsii.

Viral DNA in the blood was measured by molecular hybridization in 210 patients with acute hepatitis B (HB) running mildly. It was established that the disease chronicity may be predicted by dynamic control of HBV DNA content. Relevant algorithm has been derived. Early detection of the chronicity threat was of great importance for early start of preventive etiotropic antiviral therapy.