Bacteriochlorophyll aggregates in positively charged micelles

Micellar complexes were prepared from bacteriochlorophyll a and bacteriopheophytin a with the cationic detergents, cetyltrimethyl ammonium bromide and cetylpyridinium chloride. These complexes have spectroscopic properties (absorption, circular dichroism) which are very different from the ones formed with non-ionic detergents like Triton X-100, and also with anionic detergents. Bacteriochlorophyll a forms two complexes: One is blue-shifted and has excitonically coupled Qy transitions. The second one is extremely red-shifted. The unusual properties are suggested to result from interactions of the positively charged head-group of the detergent with the tetrapyrrole

Triggering and modulation of the host-parasite interplay by Echinococcus multilocularis: a review

As more facts emerge regarding the ways in which E. multilocularis-derived molecules trigger the host immune response and modulate the host-parasite interplay, it becomes possible to envisage how the parasite can survive and proliferate in its intermediate host, while in other hosts it dies out. Through effects on cells of both the innate and adaptive arms of the immune response, E. multilocularis can orchestrate a range of outcomes that are beneficial not only to the parasite, in terms of facilitating its intrahepatic proliferation and maturation, and thus life cycle over all, but also to its intermediate host, in limiting pathology. The present review deals with the role of metacestode surface molecules as well as excretory/secretory (E/S) metabolic products of the parasite in the modulation of the host responses such as to optimize its own surviva

Adhesion and invasion of bovine endothelial cells by Neospora caninum

Neospora caninum is a recently identified coccidian parasite which was, until 1988, misdiagnosed as Toxoplasma gondii. It causes paralysis and death in dogs and neonatal mortality and abortion in cattle, sheep, goats and horses. The life-cycle of Neospora has not yet been elucidated. The only two stages identified so far are tissue cysts and intracellularly dividing tachyzoites. Very little is known about the biology of this species. We have set up a fluorescence-based adhesion/invasion assay in order to investigate the interaction of N. caninum tachyzoites with bovine aorta endothelial (BAE) cells in vitro. Treatment of both host cells and parasites with metabolic inhibitors determined the metabolic requirements for adhesion and invasion. Chemical and enzymatic modifications of parasite and endothelial cell surfaces were used in order to obtain information on the nature of cell surface components responsible for the interaction between parasite and host. Electron microscopical investigations defined the ultrastructural characteristics of the adhesion and invasion process, and provided information on the intracellular development of the parasite

ДЕЦЕНТРАЛИЗОВАННОЕ УПРАВЛЕНИЕ В ЗАДАЧАХ ОПЕРАТИВНОГО РАСПРЕДЕЛЕНИЯ РЕСУРСОВ

В работе проводится краткое описание существующих на сегодня структур систем управления. Особое внимание уделяется системам децентрализованного управления, которые имеют ряд преимуществ по сравнению остальными, а именно – повышенная надежность и возможность экономии на линиях связи

Modeling and analysis of own oscillations of the TFB with turbine 500 Mw

Проведен анализ собственных колебаний системы турбоагрегат-фундамент-основание с турбиной мощностью 500 МВт в частотном диапазоне приближенном к частоте колебаний электромагнитной природы от генератора. Объектом исследования является система турбоагрегат-фундамент-основание.. Для исследования выбрана система с паровой турбиной, которая содержит несколько типовых корпусов. Для моделирования и проведения численных расчетных исследований использован метод конечных элементов. Построены геометрические и конечно-элементные модели системы турбоагрегат-фундамент-основание с учетом особенностей взаимодействия гибких корпусов турбины с фундаментом. Проведены расчеты собственных колебаний. Получены собственные частоты и формы колебаний. Полученные результаты дают качественную оценку причин повышенной вибрации отдельных элементов рассматриваемой системы.The analysis of the own oscillations of the turbounit-foundation-base system is carried out. The system includes a reinforced concrete foundation, a 500 MW turbine with five bodies, a generator and four condensers. To study the chosensystem with a steam turbine, which contains several typical buildings. The relevance of the study is due to the presence of turbounit-foundation-base systems with a long operating time and a significant development of the base resource of increased levels of vibration. On the other hand, the relevance and novelty of the results is due to the lack of previousresearch on the given object and subject of research. A system with a steam turbine with four typical identical flexible housings and one rigid body of high weight is considered. The system of turbine-base-base in the frequency range close to the frequency of oscillations of electromagnetic naturefrom the generator was considered. The object of the study is a turbo-base-base system. The method of finite elements is used for modeling and conducting numerical calculations. The geometric and finite-element models of the turbo unit-foundation-base system are constructed taking into account the features of the interaction of flexible bodies of the turbine with the foundation. The modeling of the foundation is done using a system of core and mass finite element. The rigid body of the steam turbine and the generator were modeled using a system of massive finite elements. The most flexible bodies of the steam turbine weremodeled using a shell, coreand mass finite element system. The basis was modeled using the system of stiffness and boundary conditions. Capacitors were modeled using a system of stiffness and boundary conditions. The peculiarity of the calculation models is the detailed three-dimensional modeling of flexible bodies of the steam turbine. The applied simulation technique is unique and allows us to carry out a detailed analysis of the system's own oscillations. The calculations of proper oscillations have been carried out. Own frequencies and forms of oscillations are obtained.The obtained results give a qualitative estimation of the internal oscillations of separate elements of the considered system of the turbo-aggregate-foundation-base and the system as a whole. The results ofthe calculations were used inthe study of the causes of increased vibration of the turbo unit-foundation-base system and its individual elements

О механизме сольватации ионов и радиусах сольватированных ионов галогеноводородов в н-спиртах

На основе предложенной модификации двухслойной модели Абрахама и Лиси рассчитаны эффективные радиусы (rᵢ) и величины изменения энергии Гиббса сольватации (ΔcGᵢ⁰) для бромид-, иодид-ионов и ионов Н⁺ в ряду н-спиртов от метанола до октанола при 5-55°С. Показано, что данная модификация согласуется с механизмом сольватации ионов, который сводится к уменьшению свободной энергии системы за счет нейтрализации заряда иона и перераспределения заряда с окружающими молекулами растворителя.Modification of double-layer model Abraham-Liszi is offered by authors both effective radii (rᵢ) and values of changes of Gibbs energy solvation (ΔcGᵢ⁰) for bromide- and iodide-ions in a series of primary alcohols from methanol to octanol are calculated at 278.15-328.15 K on the basis of this modification. The latter consider the mechanism of ions solvation better. This mechanism takes into account reduction of a free energy of system at the expense of neutralization of an ion charge and redistribution of a charge with environmental solvent molecules

Rotifer niche segregation factors

The niche space of a species has been defined as the region in N-dimensional environmental hyperspace in which the fitness of the individuals is positive. In zooplankton assemblages, there has been little consideration of how different density-dependent (i.e. resources) and density-independent (i.e. conditions) environmental factors relate to fitness components in the field, namely survival and reproduction. We studied the abundance and reproduction (egg ratio) variability of seven species of pelagic rotifers living in a high-mountain lake and their relation to a number of environmental factors by means of partial canonical correspondence analyses. The generally higher explanatory capacity of conditions over resources suggests that habitat partitioning among species largely relies on historical processes, which are internalised in life history traits of spatial and temporal habitat use. However, the increase in the relevance of resources when considering reproduction, as compared to abundance, indicates that there is still an on-going interactive niche segregation process among rotifer species, which affects present and future rotifer assemblages in the lake. Our study shows the value of considering measurements close to fitness components (e.g. egg ratio) for detecting on-going niche segregation processes in zooplankton, which may help to resolve paradoxes in relation to species coexistence in natural assemblages.Peer reviewe