Influence of static and dynamic disorder on the visible and infrared absorption spectra of carbonmonoxy horseradish peroxidase

Spectroscopy of horseradish peroxidase with and without the substrate analog, benzohydroxamic acid, was monitored in a glycerol/water solvent as a function of temperature. It was determined from the water infrared (IR) absorption that the solvent has a glass transition at 170-180 K. In the absence of substrate, both the heme optical Q(0,0) absorption band and the IR absorption band of CO bound to heme broaden markedly upon heating from 10-300 K. The Q(0,0) band broadens smoothly in the whole temperature interval, whereas the IR bandwidth is constant in the glassy matrix and increases from 7 to 16 cm(-1) upon heating above the glass transition. Binding of substrate strongly diminishes temperature broadening of both the bands. The results are consistent with the view that the substrate strongly reduces the amplitude of motions of amino acids forming the heme pocket. The main contribution to the Q(0,0) bandwidth arises from the heme vibrations that are not affected by the phase transition. The CO band thermal broadening stems from the anharmonic coupling with motions of the heme environment, which, in the glassy state, are frozen in. Unusually strong temperature broadening of the CO band is interpreted to be caused by thermal population of a very flexible excited conformational substrate. Analysis of literature data on the thermal broadening of the A, band of Mb(CO) (Ansari et al., 1987. Biophys. Chem. 26:337-355) shows that such a state presents itself also in myoglobin

A Gluing Construction Regarding Point Particles in General Relativity

We develop a gluing construction which adds scaled and truncated asymptotically Euclidean solutions of the Einstein constraint equations to compact solutions with potentially non-trivial cosmological constants. The result is a one-parameter family of initial data which has ordinary and scaled "point-particle" limits analogous to those of Gralla and Wald ("A rigorous derivation of gravitational self-force," Class. Quantum Grav. 2008). In particular, we produce examples of initial data which generalize Schwarzschild - de Sitter initial data and gluing theorems of IMP-type

Higher order Jordan Osserman Pseudo-Riemannian manifolds

We study the higher order Jacobi operator in pseudo-Riemannian geometry. We exhibit a family of manifolds so that this operator has constant Jordan normal form on the Grassmannian of subspaces of signature (r,s) for certain values of (r,s). These pseudo-Riemannian manifolds are new and non-trivial examples of higher order Osserman manifolds

Лазерные источники с безопасным излучением для импульсной дальнометрии

The paper presents the results of experimental investigations of lasers generating within spectral range of 1,5... 1,6 дт which is the most safety for eyesight. It has been studied generation characteristics of coherent radiation sources using effects of stimulated Raman scattering or parametric oscillation of light at excitation by radiation of neodymium-containing lasers with wave length of 1,32 or 1,06 fim, respectively, as well as erbium- containing lasers at lamp pumping. The paper shows the prospects of laser usage as a part of pulse range finders.Представлены результаты экспериментальных исследований лазеров, генерирующих в спектральной области 1,5... 1,6 мкм, являющейся наиболее безопасной для органов зрения. Изучены генерационные характеристики источников когерентного излучения, использующих эффекты вынужденного комбинационного рассеяния или параметрической генерации света при возбуждении излучением неодимсодержащих лазеров с длиной волны 1,32 или 1,06 мкм, а также эрбийсодержащих лазеров при ламповой накачке. Отмечена перспективность использования таких лазеров в составе импульсных дальномеров

Curvature homogeneous spacelike Jordan Osserman pseudo-Riemannian manifolds

Let s be at least 2. We construct Ricci flat pseudo-Riemannian manifolds of signature (2s,s) which are not locally homogeneous but whose curvature tensors never the less exhibit a number of important symmetry properties. They are curvature homogeneous; their curvature tensor is modeled on that of a local symmetric space. They are spacelike Jordan Osserman with a Jacobi operator which is nilpotent of order 3; they are not timelike Jordan Osserman. They are k-spacelike higher order Jordan Osserman for $2\le k\le s$; they are k-timelike higher order Jordan Osserman for $s+2\le k\le 2s$, and they are not k timelike higher order Jordan Osserman for $2\le s\le s+1$.Comment: Update bibliography, fix minor misprint

НЕКОТОРЫЕ ПУТИ СОВЕРШЕНСТВОВАНИЯ БЕЛОРУССКОЙ КОСМИЧЕСКОЙ СИСТЕМЫ ДИСТАНЦИОННОГО ЗОНДИРОВАНИЯ ЗЕМЛИ

The article discusses the possibility of improving the characteristics of the Belarusian space system of Earth remote sensing resulting from the implementation of multilevel information-integrated structure. The statement of this problem is related to the limitations that are typical for the shooting of the Earth’s surface from space, caused by both natural (insufficient viewability), and technical (inadequate recording equipment) factors. The proposed configuration of the multi-level information complex includes, besides the traditional space and ground segments, also an aviation segment and another supplementary ground measuring segment. And the aviation segment can contain both manned and unmanned aerial vehicles of different kinds, equipped with the necessary target equipment, and the supplementary ground segment – the system of accurate positioning. The main technical characteristics of the target devices that can be used to implement the complex are considered. As an example, the forecast of information capabilities of the complex for the solution of geodetic problems was considered: integration of such heterogeneous information resources at the stages of issue of the flight missions and complex data processing can significantly increase the likelihood of obtaining the necessary information for consumers.Обсуждаются возможности улучшения характеристик Белорусской космической системы дистанционного зондирования Земли, вытекающие из реализации ее многоуровневой информационно-интегрированной структуры. Предлагаемая конфигурация многоуровневого информационного комплекса включает в себя помимо традиционных космического и наземного сегментов также авиационный и дополнительный наземный сегменты. При этом авиационный сегмент может содержать как пилотируемые, так и беспилотные летательные аппараты различных типов, оснащенные необходимой целевой аппаратурой, а дополнительный наземный сегмент – спутниковую систему точного позиционирования. В качестве примера рассмотрен прогноз информационных возможностей такого комплекса при решении геодезических задач

Theoretical study of the distal-side steric and electrostatic effects on the vibrational characteristics of the FeCO unit of the carbonylheme proteins and their models.

The vibronic theory of activation and quantum chemical intermediate neglect of differential overlap (INDO) calculations are used to study the activation of carbon monoxide (change of the C-O bond index and force field constant) by the imidazole complex with heme in dependence on the distortion of the porphyrin ring, geometry of the CO coordination, iron-carbon and iron-imidazole distances, iron displacement out of the porphyrin plane, and presence of the charged groups in the heme environment. It is shown that the main contribution to the CO activation stems from the change in the sigma donation from the 5 sigma CO orbital to iron, and back-bonding from the iron to the 2 pi orbital of CO. It follows from the results that none of the studied distortions can explain, by itself, the wide variation of the C-O vibrational frequency in the experimentally studied model compounds and heme proteins. To study the dependence of the properties of the FeCO unit on the presence of charged groups in the heme environment, the latter are simulated by the homogeneous electric field and point charges of different magnitude and location. The results show that charged groups can strongly affect the strength of the C-O bond and its vibrational frequency. It is found that the charges located on the distal side of the heme plane can affect the Fe-C and C-O bond indexes (and, consequently, the Fe-C and C-O vibrational frequencies), both in the same and in opposite directions, depending on their position. The theoretical results allow us to understand the peculiarities of the effect of charged groups on the properties of the FeCO unit both in heme proteins and in their model compounds