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The examination of residents of St. Petersburg and Petrozavodsk revealed a high frequency of vitamin D deficiency and according to the criteria of the International Society of Endocrinology (ENDO, 2011), normal levels of vitamin D sufficiency had only 16.8% of residents of the north-western region of the Russian Federation, while vitamin D insufficiency was seen in 37.5%, and deficit — in 45.7% of patients. When reviewing the results using the criteria proposed by the U.S. Institute of Medicine (IOM, 2011), normal values of 25(OH)D in serum were detected in 49.6% insufficient levels — in 40.0% and deficit — in 10.4%. The decrease ofvitamin D levels was independent of age, but more frequent in women and people who are overweight. Given the lack of national standards for assessing the sufficiency ofvitamin D, as well as the average level of 25(OH)D in the blood serum in the study population, to assess vitamin D status in the northwestern region of Russia is preferable to use the criteria proposed by the U.S. Institute of Medicine in 2011.

The patients with obesity are known to suffer 25-hydroxy vitamin D (25(OH)D) deficiency, but the relationship between these two conditions remains unclear. The blood 25(ON)D levels in practically healthy women were compared with the amount and distribution patterns of the fatty tissue and with the content of plasma adipocytokines. The absence or deficit of vitamin D was documented in 61.3% of the women included in the present study. They exhibited negative correlation between 25(ON) D levels and body weight. The patients with obesity were characterized by correlation between the 25(ON)D levels and waist circumference, body weight, BMI, and the amount of fatty tissue. The women of reproductive age with the reduced blood 25(ON)D level ( OR 1.86 [0.88—3.95]; CI 95%) or 25(ON)D deficiency (OR 2.23 [1.03—4.80]; CI 95%) were at a higher risk of development of obesity compared with the women in whom the 25(ON)D levels were in excess of 75 nmol/l. The study confirmed correlations between adypocytokine levels and the amount of fatty tissue even though it failed to demonstrate a significant relationship between the levels of adipocytokines and vitamin D.

Российская Федерация в силу географического расположения и экономических особенностей имеет все предпосылки для развития недостатка и дефицита витамина D. Цель исследования. Оценить уровень 25(OH)D) крови у жителей Северо-Западного региона РФ для изучения распространенности дефицита витамина D и его вклада в здоровье. Материал и методы. В исследование включено 1690 человек (1349 в возрасте 18-75 лет, включая 221 беременную и 120 детей/подростков в возрасте 3-17 лет). Уровень 25(OH)D крови оценивался хемилюминесцентным методом (AbbottArchitect 8000, USA), у беременных исследование проводилось на 8-14 неделях гестации. Критерии РАОП (2015) были использованы для оценки статуса витамина D. Антропометрическое исследование включало измерение роста, веса, окружности талии (ОТ) и расчет индекса массы тела (ИМТ). У 204 женщин в возрасте 30-52 лет проведена двухэнергетическая рентгеновская абсорбциометрия (ДРА) (Lunar Prodigy, USA). У 310 жителей 25-70 летнего возраста проведена оценка наличия тревоги и депрессии при помощи опросника госпитальной шкалы тревоги и депрессии HADS. За отсутствие тревоги и депрессии принималось суммарное значение баллов 0-7, за субклинические нарушения - 8-10, за клинические - >11. Результаты. Уровень 25(OH)D в сыворотке крови варьировал от 9,8 до 147,5 нмоль/л, у взрослых в среднем был 54,8±0,7нмоль/л, у детей/подростков - 46,8±1,6 нмоль/л. У женщин 25(OH)D крови был ниже чем у мужчин (53,9±0,8 и 67,2±2,2 нмоль/л; p

The states of supported vanadium and the nature of activation of ammonia adsorbed on vanadium sites of VO x /TiO 2 catalysts are studied by 5 1 V NMR spectroscopy and diffuse-reflectance IR Fourier-transform (DRIFT) spectroscopy using cluster quantum chemical calculations of NH 3 adsorption. We employ the VO x /TiO 2 catalyst of two types: the monolayer catalyst in which vanadium is located on the surface of well-crystallized anatase and the catalyst in which vanadium embedded in the anatase lattice at a rather great depth. It is shown that ammonia is predominantly adsorbed on Lewis acid sites of the monolayer catalyst, whereas most of NH 3 adsorbed on the catalyst containing bulk vanadium is in the form of ammonium ions. Analysis of experimental and calculated data suggests that, in the monolayer catalyst, NH 3 molecules in the selective reduction of nitrogen oxides are activated on Lewis acid sites. Ammonia activation involves the dissociation of the N-H bond in a coordinated molecule, which results in the formation of the amide V-NH 2 group and a water molecule coordinated by a V 5 + ion. It is likely that, in the case of the catalyst containing bulk vanadium, this reaction occurs with the predominant participation of ammonium ions.

Molecular structures of the active vanadium phase of the VO x /TiO2 supported catalyst are calculated in the framework of the cluster approximation of density functional theory (DFT). It is shown that vanadium can be stabilized on the anatase (001) surface both in the tetrahedral and octahedral coordinations with the formation of monoxo- and dioxovanadyl structures. The energy of the dioxovanadyl structure binding to the support surface is 600–800 kJ/mol. The formation of dioxovanadyl structures from monoxovanadyl ones with the formation of water molecules is energetically favorable. The effect of support on the electronic state and acidic properties of the supported vanadium phase is discussed.

The present study deals with ZnO photoelectronic spectra (PES) recorded at 1253.6 eV as well as within a wide photon energy range of 30–150 eV. It has been shown that the shape of the O2p valence band PES depends on the incident photon energy. On the basis of SCF Xα-scattered waves (Xα-SW) cluster approximation, the O2p valence band PES have been calculated in the given photon energy range. The changes in the O2p PES shape are proved to be caused by Zn3d electrons, which participate in the covalent binding along with Zn4s electrons. The percentage of the Zn3d-states was obtained on the basis of the quantum-chemical calculations and using the photon energy dependence of the integral intensity ratio IO2p/IZn3d. Based on this result, the ZnO stoichiometry and the concentration ratio profile [O]/[Zn] as a function of the escape depth have been calculated. The weight of Zn3d-states, as evaluated from the photon energy dependence, is 9%. A theoretical prediction for this weight is 7%, which is very close to the experimental value.

The photoelectron spectra (PES) of the valence O2p-band of zinc oxide are modeled by Xα-scattered wave cluster calculations in a wide range of incident quantum energies hv (from 30 to 150 eV and 1253.6 eV). For the Zn10O10 cluster, the calculated intensities of PES reproduce well the specific features of the experimental spectra. It is shown that Zn3d-electrons participate in covalent binding of zinc and oxygen. The admixture of the Zn3d-states in the hybrid orbitals of the valence band is ≈7%.

The X-ray photoelectron spectra of zinc oxide were measured in a wide range of quantum energies (30–150 and 1253.6 eV). It is shown that the form of the spectrum of the valence O2p-band depends on the energy of the incident quantum. The most probable reason for the change in the form of the O2p-band spectra is an admixture of Zn3d-electrons, which, along with Zn4s-electronst take part in covalent bonding of Zn and O. The dependence of the integral intensity ratio of the O2p-band to the intensity of the Zn3d peak on hv was analyzed, due to which the percent of the admixture of the Zn3d-states in the O2p-band was determined to be 9%. The stoichiometry and the depth of the profile of the concentration ratio were calculated taking into account the fraction of the Zn3d-electrons participating in the bond.

For low-coordinated (N=2,3,4,5) oxygen ions on the surface and in the bulk of magnesium oxide, the behavior of the core O1s- and valence O2s-, O2p-levels is considered. The MgO610−, OMg610+, Mg13O142−, O13Mg142+, Mg4O76−, and OMg22+ clusters are calculated by the SCF-Xα-SW method. The binding energies of oxygen 1s-, 2s-, and 2p-states decrease with coordination. This coordination dependence is explained by the greater change of the Madelung potential as compared to variations of the purely electronic terms of the binding energies of oxygen ions. The dependence of oxygen atomic charges and relaxation energies on coordination is also discussed.

The behavior of core 01s levels for low-coordinated (3, 4, 5) oxygen ions on the surface and in the bulk of magnesium oxide has been studied. Mg13O142− and Mg14O132+ clusters have been calculated by the SCF MS Xα method. Binding energies of 1s oxygen states are found to decrease with lowering coordination. This dependence on coordination is attributed to the larger changes in Madelung potential compared to those of pure electron contributions to the binding energy of electrons in oxygen ion. The coordination dependence of ion oxygen charges and relaxation energies is also discussed.

Studies of the influence of electric fields on the chemisorption and catalytic properties of semiconductor catalysts, carried out in order to test the principal postulates of the electronic theory of catalysis, are examined. It is shown that, because of the high density of the surface states, the possibility of the electronic control of the surfaces of polycrystalline catalysts by the field effect method is extremely limited. Possible ways of regulating the chemisorption and catalytic activities of solid catalysts with the aid of an external electric field are discussed: (1) the change in the concentration of polar molecules in strong inhomogeneous local fields near the surface; (2) the activation of surface compounds by hot electrons; (3) the modification of the defective structure when the concentration of cations in the surface layers of oxide catalysts is altered; (4) surface doping of film catalysts by alkali metals from the dielectric support during their electrolytic deposition. 130 references.

Strong interaction of Pt with a TiO2 support (reductive high-temperature treatment) is shown to increase the catalytic activity due to a decrease in CO coverage of the active Pt surface.

It is shown that the deactivation of Na-promoted Pt/TiO2 catalysts is due to increasing the strenght of Pt−Co bond. This can be attributed to the variations in the chemical composition and the structure of CO-containing platinum compounds.

Electrolytic supporting of metallic sodium on the surface of TiO2 and Pt/TiO2 films is shown to change significantly the Fermi level of the semiconductor substrate already at small concentrations of sodium. The steady-state catalytic activity changes only at high concentrations of supported sodium, varying the chemical composition of the active phase. The contact process does not play any significant role in the catalytic process.

The induction of negative charge in a ZnO film causes oxigen adsorption on an oxidized surface apparently in the form of O2−. Electroadsorbed oxygen forms CO adsorption centers. On coadsorption from a 2CO+O2 mixture, equal quantities of CO and O2 are adsorbed with the formation of CO3− complexes decomposing above 400 °C with CO2 liberation into the gas phase.