Lattice Model for water-solute mixtures

A lattice model for the study of mixtures of associating liquids is proposed. Solvent and solute are modeled by adapting the associating lattice gas (ALG) model. The nature of interaction solute/solvent is controlled by tuning the energy interactions between the patches of ALG model. We have studied three set of parameters, resulting on, hydrophilic, inert and hydrophobic interactions. Extensive Monte Carlo simulations were carried out and the behavior of pure components and the excess properties of the mixtures have been studied. The pure components: water (solvent) and solute, have quite similar phase diagrams, presenting: gas, low density liquid, and high density liquid phases. In the case of solute, the regions of coexistence are substantially reduced when compared with both the water and the standard ALG models. A numerical procedure has been developed in order to attain series of results at constant pressure from simulations of the lattice gas model in the grand canonical ensemble. The excess properties of the mixtures: volume and enthalpy as the function of the solute fraction have been studied for different interaction parameters of the model. Our model is able to reproduce qualitatively well the excess volume and enthalpy for different aqueous solutions. For the hydrophilic case, we show that the model is able to reproduce the excess volume and enthalpy of mixtures of small alcohols and amines. The inert case reproduces the behavior of large alcohols such as, propanol, butanol and pentanol. For last case (hydrophobic), the excess properties reproduce the behavior of ionic liquids in aqueous solution.Comment: 28 pages, 13 figure

Evolution of polarization orientations in a flat universe with vector perturbations: CMB and quasistellar objects

Various effects produced by vector perturbations (vortical peculiar velocity fields) of a flat Friedmann-Robertson-Walker background are considered. In the presence of this type of perturbations, the polarization vector rotates. A formula giving the rotation angle is obtained and, then, it is used to prove that this angle depends on both the observation direction and the emission redshift. Hence, rotations are different for distinct quasars and also for the cosmic microwave background (CMB) radiation coming along different directions (from distinct points of the last scattering surface). As a result of these rotations, some correlations could appear in an initially random field of quasar polarization orientations. Furthermore, the polarization correlations of the CMB could undergo alterations. Quasars and CMB maps are both considered in this paper. In the case of linear vector modes with very large spatial scales, the maximum rotation angles appear to be of a few degrees for quasars (located at redshifts z<2.6) and a few tenths of degree for the CMB. These last rotations produce contributions to the B mode of the CMB polarization which are too small to be observed with PLANCK (in the near future); however, these contributions are large enough to be observed with the next generation of satellites, which are being designed to detect the small B mode produced by primordial gravitational waves

Dynamical charge inhomogeneity and crystal-field fluctuations for 4f ions in high-Tc cuprates

The main relaxation mechanism of crystal-field excitations in rare-earth ions in cuprates is believed to be provided by the fluctuations of crystalline electric field induced by a dynamic charge inhomogeneity generic for the doped cuprates. We address the generalized granular model as one of the model scenario for such an ingomogeneity where the cuprate charge subsystem remind that of Wigner crystal with the melting transition and phonon-like positional excitation modes. Formal description of R-ion relaxation coincides with that of recently suggested magnetoelastic mechanism.Comment: 4 page

Future of superheavy element research: Which nuclei could be synthesized within the next few years?

Low values of the fusion cross sections and very short half-lives of nuclei with Z$>$120 put obstacles in synthesis of new elements. Different nuclear reactions (fusion of stable and radioactive nuclei, multi-nucleon transfers and neutron capture), which could be used for the production of new isotopes of superheavy (SH) elements, are discussed in the paper. The gap of unknown SH nuclei, located between the isotopes which were produced earlier in the cold and hot fusion reactions, can be filled in fusion reactions of $^{48}$Ca with available lighter isotopes of Pu, Am, and Cm. Cross sections for the production of these nuclei are predicted to be rather large, and the corresponding experiments can be easily performed at existing facilities. For the first time, a narrow pathway is found to the middle of the island of stability owing to possible $\beta^+$-decay of SH isotopes which can be formed in ordinary fusion reactions of stable nuclei. Multi-nucleon transfer processes at near barrier collisions of heavy (and very heavy, U-like) ions are shown to be quite realistic reaction mechanism allowing us to produce new neutron enriched heavy nuclei located in the unexplored upper part of the nuclear map. Neutron capture reactions can be also used for the production of the long-living neutron rich SH nuclei. Strong neutron fluxes might be provided by pulsed nuclear reactors and by nuclear explosions in laboratory conditions and by supernova explosions in nature. All these possibilities are discussed in the paper.Comment: An Invited Plenary Talk given by Valeriy I. Zagrebaev at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS

Polar Jahn-Teller Centers and Isotope Effect in Copper Oxide High-Tc-superconductors

The CuO4-cluster based copper oxides are considered as generalized quantum lattice bose-gas or a system of the local singlet bosons moving in a lattice of the hole Jahn-Teller centers [CuO45-]JT. The model is illustrated by the qualitative and quantitative description of the various peculiarities of an isotope shift (IS-) effect in a series of 123-like oxides

Metabolic model for laboratory control of anti-ischaemic therapy effectiveness: a case study of nicorandil

Scientific relevance. A key anti-ischaemic mechanism of some medicinal products involves their effects on the metabolism of endothelial vasodilators, particularly the synthesis of nitric oxide from arginine and its precursor citrulline.Aim. The study was aimed to determine whether the plasma time course of guanidine derivatives (arginine precursors) is applicable to laboratory control of anti-ischaemic therapy effectiveness using a single oral dose of nicorandil in patients with coronary heart disease as a case study.Materials and methods. The authors used high-performance liquid chromatography to determine metabolites. Blood samples for analysis were obtained from 30 patients with angina pectoris (Grade II–III, Canadian Cardiovascular Society) and 30 healthy donors. All the study participants received a single oral dose of 20 mg nicorandil after 10 h of fasting.Results. At baseline, patients showed significantly higher plasma citrulline levels than donors. However, the elevated levels decreased to the healthy range after nicorandil administration. Plasma arginine levels in patients showed a statistically significant increase following nicorandil administration. Plasma homoarginine levels in patients remained reduced both before and after dosing. Nicorandil did not influence elevated levels of the endogenous nitric oxide synthase inhibitor (asymmetrical dimethylarginine).Conclusions. In addition to the established mechanisms responsible for altering cell metabolism, nicorandil enhances the contribution of citrulline to arginine resynthesis. It is reasonable to include citrulline and arginine, which are involved in the vasodilator response, in model schemes for laboratory control of the effectiveness of anti-ischaemic therapy

Численый анализ двумерной задачи сверхзвуковых взаимодействий скачка уплотнения с пограничным слоем

Наведено результати числового моделювання характеру взаємодій надзвукових турбулентних течій в області нахиленої з навітряної грані сходинки для кута нахилу відносно горизонту β = 8, 25, 90° та чисел Маха M∞ = 2,9, 2,94. В якості математичної моделі використані осереднені за Рейнольдсом рівняння Нав’є-Стокса з використанням моделі турбулентності k-ω SST для в’язкого стисливого середовища. Проведено порівняльний аналіз розподілу тиску та поверхневого тертя з наявними експериментальними даними.The results of numeric modeling of the nature of supersonic turbulent flows interaction in the field of inclined from the windward side plane of the step for the canting angle β = 8, 25, 90° and Mach numbers M∞ = 2,9, 2,94. The Navier-Stokes equations averaged by Reynolds with the usage of turbulent model were used as a mathematical model k-ω SST for viscous compressed environment. Comparative analysis of the pressure distribution and surface friction with gained experimental data was held.Приведены результаты численного моделирования характера взаимодействий сверхзвуковых турбулентных течений на наклоном участке с наветренной грани ступеньки для угла наклона относительно горизонта β = 8, 25, 90° та чисел Маха M∞ = 2,9, 2,94. В качестве математической модели использованы усредненные за Рейнольдсом уравнения Навье-Стокса с использованием модели турбулентности k-ω SST для вязкой сжимаемого среды. Проведен сравнительный анализ распределения давления и поверхностного трения с имеющимися экспериментальными данными

Frequency of undesirable situations and critical incidents during intrahospital transportation of patients

The article considers the results of 221 Intrahospital transport of critically ill patients. The study found that hemodynamic monitoring performed during the transfer process in only 28.5% of patients and the use of manual Ambu ventilation in more than half of patients are factors that contribute to a decrease in the quality of transportation. Insufficient data on statistics of undesirable situations and critical incidents during intrahospital transport of patients can serve as an occasion for in-depth study of this problem and the creation of a database for the purpose of recording and analyzing the quality and risks of intrahospital transfer.В статье рассмотрены результаты 221 внутригоспитальной транспортировки пациентов, находящихся на лечение в отделении реанимации и интенсивной терапии. В ходе исследования было установлено, что гемодинамический мониторинг, проводимый в процессе трансфера лишь у 28,5% пациентов и применение у большей половины пациентов ручной искусственной вентиляции легких является факторами, способствующими снижению качества транспортировки. Недостаточное количество данных о статистике нежелательных ситуаций и критических инцидентах при проведении внутригоспитальной транспортировки пациентов может служить поводом для углубленного изучения данной проблемы и создания базы данных с целью регистрации и анализа качества и рисков при проведении внутригоспитального трансфера

Performance and Operation of the CMS Electromagnetic Calorimeter

The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented