SELF-CONSISTENT FIELD MODEL OF BRUSHES FORMED BY ROOT-TETHERED DENDRONS

We present an analytical self-consistent field (scf) theory that describes planar brushes formed by regularly branched root-tethered dendrons of the second and third generations. The developed approach gives the possibility for calculation of the scf molecular potential acting at monomers of the tethered chains. In the linear elasticity regime for stretched polymers, the molecular potential has a parabolic shape with the parameter k depending on architectural parameters of tethered macromolecules: polymerization degrees of spacers, branching functionalities, and number of generations. For dendrons of the second generation, we formulate a general equation for parameter k and analyze how variations in the architectural parameters of these dendrons affect the molecular potential. For dendrons of the third generation, an analytical expression for parameter k is available only for symmetric macromolecules with equal lengths of all spacers and equal branching functionalities in all generations. We analyze how the thickness of dendron brush in a good solvent is affected by variations in the chain architecture. Results of the developed scf theory are compared with predictions of boxlike scaling model. We demonstrate that in the limit of high branching functionalities, the results of both approaches become consistent if the value of exponent bin boxlike model is put to unity.In conclusion, we briefly discuss the systems to which the developed scf theory is applicable. These are: planar and concave spherical and cylindrical brushes under various solvent conditions (including solvent-free melted brushes) and brush-like layers of ionic (polyelectrolyte) dendrons

Micellization of Sliding Polymer Surfactants

Following up a recent paper on grafted sliding polymer layers (Macromolecules 2005, 38, 1434-1441), we investigated the influence of the sliding degree of freedom on the self-assembly of sliding polymeric surfactants that can be obtained by complexation of polymers with cyclodextrins. In contrast to the micelles of quenched block copolymer surfactants, the free energy of micelles of sliding surfactants can have two minima: the first corresponding to small micelles with symmetric arm lengths, and the second corresponding to large micelles with asymmetric arm lengths. The relative sizes and concentrations of small and large micelles in the solution depend on the molecular parameters of the system. The appearance of small micelles drastically reduces the kinetic barrier signifying the fast formation of equilibrium micelles.Comment: Submitted to Macromolecule

Self-Consistent Field study of Polyelectrolyte Brushes

We formulate a self-consistent field theory for polyelectrolyte brushes in the presence of counterions. We numerically solve the self-consistent field equations and study the monomer density profile, the distribution of counterions, and the total charge distribution. We study the scaling relations for the brush height and compare them to the prediction of other theories. We find a weak dependence of the brush height on the grafting density.We fit the counterion distribution outside the brush by the Gouy-Chapman solution for a virtual charged wall. We calculate the amount of counterions outside the brush and find that it saturates as the charge of the polyelectrolytes increases

Специалистическая модель в условиях непрерывного профессионального образования

Fundamental changes in the Russian economy determined by the increasing role of knowledge, the revolution in information and communication technologies, the formation of the global labor market, as well as political changes, dictate new requirements for professional training. The specialist model, professiogram, qualification characteristic, sociogram of profession, sociogram of professional identity is the view options of the ideal result of students’ training. The key competence is the defining competence because it corresponds to the conditions of implementation, which are neither limited, not too specific, but are to a certain extent universal. The essence of professional competence of a specialist is the integration of knowledge, skills, experience; personal qualities that provide professional development and self-realization of a specialist, i.e. personal opportunities that allow solving professional problems independently and effectively. The perspective direction of improvement of specialists training in professional education system is development of their models giving the chance to study more deeply problems of training and use of experts, to estimate quality of educational institutions work. In recent years, research aimed at developing a specialist model has covered not only the sphere of higher education; they are conducted in the systems of basic and secondary vocational education. One of the main means of rationing and assessing the quality of professional training of students is a competence model that allows getting the clearest information about the composition of competencies that must be formed in the future specialist in the learning process. The analysis of requirements to specialists training, the contents and technologies of educational process, methodology and practice of modern educational activity allows defining a number of principles and methods of formation of specialist model as bases of a component of the Federal State Educational Standard.Los cambios fundamentales en la economía rusa, determinados por el papel cada vez mayor del conocimiento, la revolución en las tecnologías de la información y la comunicación, la formación del mercado laboral mundial, así como los cambios políticos, dictan nuevos requisitos para la formación profesional. El modelo de especialista, el profesiograma, la característica de calificación, el sociograma de la profesión, el sociograma de la identidad profesional son las opciones de visualización del resultado ideal de la formación de los estudiantes. La competencia clave es la competencia definitoria porque corresponde a las condiciones de implementación, que no son limitadas, ni demasiado específicas, pero en cierta medida son universales. La esencia de la competencia profesional de un especialista es la integración de conocimientos, habilidades, experiencia; cualidades personales que proporcionan desarrollo profesional y autorrealización de un especialista, es decir, oportunidades personales que permiten resolver problemas profesionales de manera independiente y efectiva. La dirección de la perspectiva de mejora de la formación de especialistas en el sistema de educación profesional es el desarrollo de sus modelos que brinden la oportunidad de estudiar más profundamente los problemas de formación y uso de expertos, para estimar la calidad del trabajo de las instituciones educativas. En los últimos años, la investigación dirigida a desarrollar un modelo especializado ha cubierto no solo el ámbito de la educación superior; se llevan a cabo en los sistemas de educación vocacional básica y secundaria. Uno de los principales medios para racionar y evaluar la calidad de la formación profesional de los estudiantes es un modelo de competencia que permita obtener la información más clara sobre la composición de las competencias que deben formarse en el futuro especialista en el proceso de aprendizaje. El análisis de los requisitos para la capacitación de especialistas, los contenidos y las tecnologías del proceso educativo, la metodología y la práctica de la actividad educativa moderna permite definir una serie de principios y métodos de formación de modelos especializados como bases de un componente del Estándar Educativo del Estado Federal.Фундаментальные изменения в российской экономике, обусловленные растущей ролью знаний, революцией в информационных и коммуникационных технологиях, формированием мирового рынка труда, а также политическими изменениями, диктуют новые требования к профессиональной подготовке. Модель специалиста, профессиограмма, квалификационная характеристика, социограмма профессии, социограмма профессиональной идентичности - это варианты выбора идеального результата обучения студентов. Ключевой компетенцией является определяющая компетенция, поскольку она соответствует условиям реализации, которые не являются ни ограниченными, ни слишком конкретными, но в определенной степени универсальными. Суть профессиональной компетентности специалиста - интеграция знаний, навыков, опыта; личные качества, которые обеспечивают профессиональное развитие и самореализацию специалиста, то есть личные возможности, позволяющие самостоятельно и эффективно решать профессиональные проблемы. Перспективным направлением совершенствования подготовки специалистов в системе профессионального образования является разработка их моделей, позволяющих глубже изучить проблемы подготовки и использования специалистов, оценить качество работы учебных заведений. В последние годы исследования, направленные на разработку модели специалиста, охватывали не только сферу высшего образования; они ведутся в системах начального и среднего профессионального образования. Одним из основных средств нормирования и оценки качества профессиональной подготовки студентов является модель компетенций, позволяющая получить наиболее четкую информацию о составе компетенций, которые должны быть сформированы у будущего специалиста в процессе обучения. Анализ требований к подготовке специалистов, содержания и технологий учебного процесса, методологии и практики современной образовательной деятельности позволяет определить ряд принципов и методов формирования модели специалиста как основы компонента Федерального государственного образовательного стандарта

Degradation versus self-assembly of block copolymer micelles

The stability of micelles self-assembled from block copolymers can be altered by the degradation of the blocks. Slow degradation shifts the equilibrium size distribution of block copolymer micelles and change their properties. Quasi-equilibrium scaling theory shows that the degradation of hydrophobic blocks in the core of micelles destabilize the micelles reducing their size, while the degradation of hydrophilic blocks forming coronas of micelles favors larger micelles and may, at certain conditions, induce the formation of micelles from individual chains.Comment: Published in Langmuir http://pubs.acs.org/doi/pdf/10.1021/la204625

Environmental factors in a population-based inception cohort of inflammatory bowel disease patients in Europe--an ECCO-EpiCom study.

To access publisher's full text version of this article click on the hyperlink at the bottom of the pageThe incidence of inflammatory bowel disease (IBD) is increasing in Eastern Europe possibly due to changes in environmental factors towards a more "westernised" standard of living. The aim of this study was to investigate differences in exposure to environmental factors prior to diagnosis in Eastern and Western European IBD patients.The EpiCom cohort is a population-based, prospective inception cohort of 1560 unselected IBD patients from 31 European countries covering a background population of 10.1 million. At the time of diagnosis patients were asked to complete an 87-item questionnaire concerning environmental factors.A total of 1182 patients (76%) answered the questionnaire, 444 (38%) had Crohn's disease (CD), 627 (53%) ulcerative colitis (UC), and 111 (9%) IBD unclassified. No geographic differences regarding smoking status, caffeine intake, use of oral contraceptives, or number of first-degree relatives with IBD were found. Sugar intake was higher in CD and UC patients from Eastern Europe than in Western Europe while fibre intake was lower (p<0.01). Daily consumption of fast food as well as appendectomy before the age of 20 was more frequent in Eastern European than in Western European UC patients (p<0.01). Eastern European CD and UC patients had received more vaccinations and experienced fewer childhood infections than Western European patients (p<0.01).In this European population-based inception cohort of unselected IBD patients, Eastern and Western European patients differed in environmental factors prior to diagnosis. Eastern European patients exhibited higher occurrences of suspected risk factors for IBD included in the Western lifestyle.Danish Colitis Crohn Patients Organisation (CCF) Vibeke Binder and Povl Riis Foundation Scientific Council at Herlev Hospital Sigrid Rignnor Moran Foundation, Aage and Johanne Louis-Hansens Foundation Munkholm Foundation C.C. Klestrup and Henriette Klestrup Foundation Knud and Dagny Gad Andresens Foundation Else and Mogens Wedell-Wedellsborgs Foundation Direktor Jacob Madsen and Olga Madsen's Foundation, Scan Ve

MODEL OF THE EARLY LOGOPEDIC HELP TO CHILDREN WITH A SPEECH DELAY

The article discusses The current situation regarding логопедической assistance for children of early age. The main directions of the work that defines the model of the early pedagogical support and efficiency of the socialization of this category of inmates