Functionalized azamacrocyclic compounds as Ca2+ sensitive contrast agents for MR imaging

The ability to non-invasively observe changes in Ca2+ concentration is important for neuroscience. We have therefore developed a series of gadolinium chelate complexes based on DO3A (Scheme 1), which is hypothesized to change relaxivity in magnetic resonance experiments dynamically with Ca2+ concentration. Different lengths of the phosphonate side chains are expected to lead to different binding constants of the phosphonate - gadolinium bonds. The latter property can be exploited for fine-tuning the sensitivity of the agent to calcium ion concentration

The Penning Discharge Experimental Study and Its Simulation

The influence of the demountable Penning ion source electrodes geometry on the discharge characteristics and extracted ion current is investigated. The extracted currents, ignition potentials and the operational pressure ranges are compared at different anode heights and its arrangement relative to the discharge cell. The use of ring and mesh anodes has allowed to visualize the discharge burning areas and their structure versus the pressure, anode potential and cell geometry. Some PIC simulations of Penning discharge are made in the Vorpal code. The good correspondence between the simulated electron density and plasma glow areas on the photos is shown. The other one-particle simulation has shown that the magnetic field nonuniformity significantly affects the ignition and combustion discharge potentials

Azamacrocyclic Ca2+ Sensitive Contrast Agents for MR Imaging

As calcium plays an important role in regulating a great variety of neuronal processes, many efforts are already made to generate gadolinium complexes that can act as a calcium-sensors in MRI.1 We developed a series of the DO3A-based macrocyclic and bismacrocyclic gadolinium chelates, bearing phosphonate groups as an additional coordination sites. These complexes are hypothesized to change the MRI contrast dynamically with Ca2+ concentration. Different lengths of the phosphonate side chains are exploited for fine-tuning the sensitivity of the agent to calcium ion concentration

Smart MRI Agents Sensing Extracellular Calcium Fluctuations

Functional Magnetic Resonance Imaging (fMRI) is currently the main tool used for the study of function and dysfunction of the human brain. The current mainstay of fMRI, the so-called Blood-Oxygen-Level-Dependent (BOLD) contrast, capitalizes on the detection of changes in cerebral blood flow, volume and oxygenation, but cannot directly report neural activity, as it suffers from poor spatiotemporal resolution and specificity compared to the actual neural events. An alternative methodology could be that relying on the responsive, ‘smart’ contrast agents whose relaxivity depends on the concentration of substances directly related to neuronal activity. Ca2+ is an excellent marker closely linked to brain activation and is preferred target for various imaging methods. We report two Gd3+ chelates linked to a modified EGTA moiety that have a relaxivity response to extracellular Ca2+ fluctuations in the brain. The proton relaxivity of both Gd3+ complexes is sensitive to the variation of Ca2+ concentration. They are selective to Ca2+ with respect to the main competitor cation Mg2+. Upon interaction with Ca2+, the complexes exhibit high and reversible relaxivity changes; the relaxivity response of one complex upon addition of Ca2+ exceeds 80. Moreover, the relaxivity changes remain remarkable (>50) even in the medium mimicking the brain extracellular fluid, exhibiting a ~10 relaxivity change in the physiologically relevant Ca2+ concentration range (changes induced during the neural activity). These agents have great potential to be applied as functional MR markers and be used for the visualization of the neural processes. They can substantially increase the specificity and spatial resolution of the MR-detected signals and open new perspectives in fMRI

Применение современных информационных технологий при прогнозировании расхода воздуха для помещений здания

A special attention has been paid lately to creation of the required microclimate in buildings being used for various purposes. In order to create normal air environment in buildings it is necessary to develop forecasting models with the purpose of periodic regulation of air consumption which is supplied to the buildings according to parameters of external climate and character of the work to be carried out in these rooms.The paper considers possibilities to apply modern information technologies for forecasting air consumption. The proposed model allows to create a qualitative air regime in the rooms with due account of power saving.В последнее время уделяется особое внимание созданию требуемого микроклимата в зданиях различного назначения. Для создания нормальной воздушной среды в зданиях необходимо разработать прогнозные модели с целью периодического регулирования расхода воздуха, подаваемого в помещения, в зависимости от параметров наружного климата и характера выполняемой работы в этих помещениях.Рассматриваются возможности применения современных информационных технологий для прогнозирования расхода воздуха. Предложенная методика позволяет создать в помещениях качественный воздушный режим с учетом энергосбережения

Guaranteed Solution and its Finding in the Integer Programming Problems

Abstract In the work the definitions of the guaranteed solution and guaranteed suboptimal solution are given for the multiconstraint integer programming problem. A method is developed for finding these solitions. This method is based on the sequental changing of the right hand side of the system of constraints by the dichotomia ous principle

Identification of the body most affected injuries in breast cell damage

The article deals highlights for combined chest damage. Exactly I wanted to find out the organ most susceptible to injuries in case of chest injuries.В статье рассмотрены основные моменты, касающиеся сочетанных повреждений груди, а именно выявляется наиболее подверженный травматизму орган при повреждениях грудной клетки