Tajikistan: 'Revolutionary situation' or a Resilient state? EUCAM Policy Brief 12, 19 December 2009

Since 2008, after the period of relative growth and social stability, the situation in Tajikistan has been steadily deteriorating; thus leading to increased speculation that the country could emerge as a failing state. Given its proximity to Afghanistan and Pakistan, and the role it plays in the Northern Distribution Network, a line that funnels military supplies from Europe to NATO ISAF troops in Afghanistan, the ramifications of potential instability in Tajikistan would resonate beyond the country. The current brief assesses to what extent such danger is in fact real by outlining developments in the key areas of economy and security, and examining the regime’s coping capacity to deal with emerging challenges

Kyrgyzstan: Balancing on the Verge of Stability. EUCAM Policy Brief No. 19, July 2011

Following the ‘revolution’ in April 2010, the subsequent interethnic violence in June and the recent international inquiry into these events, Kyrgyzstan is not in safe waters yet. The coming period leading up to the Presidential elections will be important for the country’s stability. What is the current situation in the South of the country, which saw clashes between Kyrgyz and Uzbeks, and what are the expectations for the presidential elections? Is Kyrgyzstan on the road to democracy, and what role can external actors play

Donbas: Seven Years On, Peace No More in Sight

• The insurgency in Donbas has consolidated both politically and militarily while drifting closer to Russia. • The Russian leadership believes that a conflict settlement based on the Minsk Agreements is unlikely to happen soon, and changes its approach towards greater engagement in, and integration of, the territories

Research of the oilseeds ratio on the oxidative stability of the protein-fat base for sportsmen

The problem of improving physical performance and accelerating the course of recovery processes after physical exertion is one of the most pressing problems of medicine and sports. Nutrition is one of the main controlled factors that ensure the normal development of the body, health and quality of life. Nowadays the assortment of products is mainly expanded due to introduction of new technologies, application of new chemical compounds, development of genetic engineering. At the same time, daily food cannot provide the athlete's body with nutrients in the required amount. And, as a result, in recent years, to speed up regeneration, actively replenish spent plastic and energy resources, very often in sports use biologically active additives. One of the promising areas for improving the efficiency of athletes is the introduction in food rations qualitatively new food products that meet the needs of their body and at the same time have a long shelf life. The aim of this study is to evaluate the oxidation processes of the protein-fat basis, which can be used to organize the rational nutrition of athletes. The oxidative stability of the crushed sunflower seeds, sesame seeds, flax and mixtures was studied at various component ratios. It has been established that sesame seeds are the least susceptible to oxidation, and most of all – flax seeds. Among mixtures of seeds, the most prone to oxidation are mixtures that contain flax seeds and sunflower seeds. When adding sesame seeds to the mixture, the oxidative stability increases sharply. The optimal content (% by weight) of oil seeds in a protein-fat basis was calculated using the method of mathematical experiment planning in the software package "Statistica". The period of induction of oxidation of this mixture is 1.3–1.4 times higher than the induction period of sunflower seeds and 2.7–3.0 times higher than the induction period of flax seed. The use of such basis in food technologies, in particular the confectionery industry, opens up wide opportunities for expanding the range of specialized products for athletes

Pericentric heterochromatin specificity, propagation and memory effect in mouse fibroblast

The transcriptional activity of genes as well as the conformation of transcriptionally silenced genomic regions is defined by the epigenetic state of the associated chromatin fragment. Chromatin is composed of repetitive units called nucleosomes. Each nucleosome consists of a core complex of four histones and the fragment of DNA that is wrapped around it. The distinct residues of N-terminal tails of the histones that extend out from the nucleosomal core are subject to post-translational epigenetic modifications. The composition of these modifications defines the electric charge of the histone tails and, therefore, its coupling strength with DNA. Thus, the epigenetic mark composition of each individual nucleosome governs the overall conformation of the chromatin filament. In mammals, the tight conformation of chromatin in pericentric genomic regions, called pericentric heterochromatin (PCH), is important for the stability and the proper segregation of chromosomes. The epigenetic hallmark signature of PCH is di- or trimethylation of histone H3 at lysine 9 (H3K9me2/3) enriched over the entire centromere region. This epigenetic state is constitutively maintened through cell cycle progression and throughout multiple cell generations thereby preventing chromosomal breakages, missegregation and perturbed chromosomal interactions. This work investigates the specificity, propagation and the long-term autonomous memory effect for H3K9me2/3 silencing marker in PCH in mouse fibroblasts on the single cell level. We apply fluorescent microscopy techniques, high-throughput image-processing method and mathematical modeling to test the stability of the system upon changes in the expression of the chromatin-modifying enzymes. The network operating H3K9me2/3 in PCH was constructed and translated into a deterministic system of ordinary differential equations as well as formulated stochastically using the Gillespie simulation algorithm. The model incorporates the contribution of H3K9me2/3 binding protein HP1 together with H3K9 specific methyltransferase Suv39h, the H3K9 specific demethylase JMJD2 and cell cycle dependent kinase Aurora B as well as nucleosome collision processes via DNA looping. The realization that most of these chromatin-modifying processes depend on each other and also appear to be regulated by multiple positive and negative feedback loops has lead to the proposal of nonlinear stationary and dynamical features of PCH network function. The modeling simulations have revealed an increased variability in methylation degree upon increases in JMJD2 expression in the cell. This prediction was qualitatively supported by the heterogeneity observed experimentally on the single PCH foci level. However, in the experiment the response of the whole cell population remains monostable, in spite of the presence of a bistable memory element in the network. The model explains this property confirming the significant impact of the persistent silencing origins organized by the high residence time binding of HP1-Suv39h complexes that initiate the spread of the H3K9me2/3 mark. Therefore, on the population level the bistable mechanism of silencing propagation in PCH is hidden, appearing only as severe fluctuations in the H3K9me2/3 level. In summary, a consistent model of the silencing propagation in PCH was developed. Based on that model a scenario of PCH epigenetic state maintenance and robustness towards transient perturbation and intrinsic noise is established

Structure-property relationships in polymer nanocomposites

Tese de Doutoramento em Ciência e Engenharia de Polímeros e CompósitosCarbon nanotubes/ carbon nanofibres (CNTs/CNFs) are considered to be among the most promising reinforcements for improving the mechanical properties of polymers while at the same time offering enhanced electrical and thermal conductivity. Because of their exceptionally high aspect ratio and high surface area in combination with a low density, already small volume fractions can potentially transfer their superior properties to a polymer matrix. However when used as reinforcements in polymeric composites, phenomena at the nano- and microscales, such as agglomerations, waviness/curliness, surface defects or imperfect bonding between the reinforcement and the polymer, can dramatically decrease the composite properties. The main objective of this work is to understand and to analyse how microstructural effects influence the overall composite behaviour on the macroscale in order to enable the full potential of these materials and to establish guidelines for the design of materials that meet specific requirements for the mechanical performance. Dependent on the polymer system, different processing techniques based on high shear mixing were applied to enhance the dispersion of nanoparticles in the polymer system. It was shown that the elastic moduli of polymers reinforced with CNTs/CNFs do not increase linearly for high volume fractions. The reasons for this behaviour were investigated by means of modelling approaches together with data analysis using different microscopy techniques. Information about the dispersion and distribution of nanotubes was obtained using optical light microscopy (OLM), whereas transmission electron microscopy (TEM) was used for direct observations and information about their spatial geometry and orientation. Probability distribution functions for agglomeration, length, curliness and orientation were determined for CNT reinforced nanocomposites and used as input parameters for the developed models. Preliminary studies were conducted to compare analytical models with Finite Element (FE) simulations, for modelling polymers reinforced with nanofillers of simplified geometries. They were aimed at investigating the influence of structural characteristics, such as curvature, orientation and dispersion of reinforcements, as well as of different FEs and boundary conditions on the effective elastic stiffness tensors. Based on the obtained findings a two-step homogenisation method was developed. In the first step, curved nanotubes were uniformly distributed in cube-shaped volume elements using Monte-Carlo simulations according to the prior experimentally obtained probability distribution functions of orientation and curvature parameters. The mechanical properties of these volume elements with three-dimensional (3D) spatial oriented nanostructures were evaluated by an Eshelby based analytical model and periodic homogenisation using the FE code ABAQUS. The nanoreinforcements were treated as curved hollow cylindrical structures perfectly bonded with the polymer matrix. In the FE method inclusions were incorporated into the polymer matrix using an embedded element technique. In the second homogenisation step the composite was considered as a two-phase material consisting of agglomerates in an isotropic medium made of the polymer matrix with perfectly dispersed curved nanostructures. Information about the number and sizes of agglomerates was obtained from OLM analyses. A Mori-Tanaka model was used to calculate the effective elastic properties of the resulting composite. The obtained Young’s moduli of polymeric nanocomposites were validated with experimental results, showing that the proposed technique may provide an attractive combination of accuracy, computational costs and flexibility for modelling arbitrary nanocomposites.Considera-se que os nanotubos de carbono/nanofibras de carbono (CNTs/CNFs) estão entre os reforços mais promissores para melhorar as propriedades mecânicas dos polímeros, oferecendo também uma condutividade elétrica e térmica melhorada. Devido à sua razão de aspeto e área de superfície excecionalmente elevadas em combinação com uma baixa densidade, mesmo pequenas frações volumétricas podem potencialmente transferir as suas propriedades superiores para uma matriz polimérica. Contudo, quando usados como reforços em compósitos poliméricos, fenómenos à nano e microescala, tais como aglomerações, ondulação/curvas, defeitos de superfície ou uma ligação imperfeita entre o reforço e o polímero, podem diminuir drasticamente as propriedades do compósito. O principal objetivo deste trabalho é compreender e analisar como é que efeitos microestruturais influenciam o comportamento global do composto à macroescala de modo a possibilitar o pleno potencial destes materiais e estabelecer diretrizes para a conceção de materiais que cumpram os requisitos específicos para o desempenho mecânico. Dependendo do sistema polimérico, diferentes técnicas de processamento baseadas na mistura de alto cisalhamento foram aplicadas para melhorar a dispersão de nanopartículas no sistema polimérico. Foi demonstrado que o módulo de elasticidade dos polímeros reforçados com CNTs/CNFs não aumenta linearmente para frações volumétricas elevadas. Os motivos para este comportamento foram investigados através de abordagens de modelação e da análise de dados com diferentes técnicas de microscopia. A informação sobre a dispersão e distribuição dos nanotubos foi obtida através de microscopia ótica, ao passo que para efetuar observações diretas e obter informação sobre a geometria e orientação espacial dos nanotubos se utilizou a microscopia eletrónica de transmissão (TEM). Funções de distribuição de probabilidade para a aglomeração, comprimento, curvas e orientação foram determinadas para nanocompósitos reforçados com CNTs e utilizadas como parâmetros de entrada para os modelos desenvolvidos. Foram efetuados estudos preliminares para comparar modelos analíticos com simulações de Elementos Finitos (FE), para modelar polímeros reforçados com nanopartículas de geometrias simplificadas. Procurou-se investigar a influência de características estruturais como a curvatura, orientação e dispersão dos reforços, bem como de diferentes FEs e condições de contorno, sobre os tensores de rigidez elástica efetiva. Com base nas descobertas obtidas, foi desenvolvido um método de homogeneização de duas fases. Na primeira fase, nanotubos curvados foram uniformemente distribuídos em elementos de volume em forma de cubo utilizando simulações de Monte Carlo de acordo com as funções de distribuição de probabilidade dos parâmetros de orientação e curvatura obtidas experimentalmente. As propriedades mecânicas destes elementos de volume com nanoestruturas tridimensionalmente orientadas foram avaliadas através de um modelo analítico baseado no modelo de Eshelby e da homogeneização periódica com o código FE ABAQUS. Os nanoreforços foram tratados como estruturas cilíndricas ocas e curvadas perfeitamente ligadas com matriz polimérica. No método FE foram incorporadas inclusões na matriz polimérica utilizando uma técnica de embedded element. Na segunda fase de homogeneização o compósito foi considerado como um material bifásico composto por aglomerados num meio isotrópico feito da matriz polimérica com nanoestruturas curvas perfeitamente dispersas. Informação sobre o número e o tamanho dos aglomerados foi obtida a partir de análises de OLM. Um modelo Mori-Tanaka foi utilizado para calcular as propriedades elásticas efetivas do compósito resultante. Os módulos de Young de nanocompósitos poliméricos obtidos foram validados com resultados experimentais, demonstrando que a técnica proposta pode proporcionar uma atraente combinação de precisão, custos computacionais e flexibilidade para a modelação de nanocompósitos arbitrários.European Community's Seventh Framework Programme FP7-PEOPLE-ITN-2008-238363

CONTENT OF PROTEIN AND GLYCOPROTEINS, THEIR COMPONENTS IN THE ORAL FLUID IN CHILDREN WITH CHRONIC GASTRITIS, DUODENITIS

In the oral fluid of children with chronic gastritis, duodenitis there is the increased protein content (up to 7.33±0.43 g/l) against the background of the decreasing level of glycoproteins (up to 0.03±0.01 mg/ml). Coefficient of ratio protein / glycoproteins in the oral fluid is increased by a factor of 9510, which has shown the intensive decay of protein-carbohydrate complexes and the increasing content of the protein fragments. In the composition of glycoproteins there is the reduced amount of hexosamines (up to 0.23±0.01 mmol/l), against the background of the increasing sialic acids (up to 0.16±0.01 mmol/l) and fucose (up to 0.87±0.02 mmol/l). Coefficient of ratio of terminal and corpus monosaccharides in the glycoproteins of the oral fluid in patients with chronic gastritis, duodenitis is increased by a factor of 2.41 and 3.34, as compared to the same values in the control group of children, which significantly modifies the functional properties of the protein-carbohydrate complexes

GPGPU-assisted polymer nanocomposite modelling and characterisation

Poster "Advanced Hybrid Materials I I: design and applications" (Simposio P)Development of the hybrid materials with predefined properties by addition of inorganic nanoinclusions to a polymer material constitutes a hard challenge due to significant properties’ variations depending on inclusion’s distribution and interaction. To understand structure-property relations in such materials optical image analysis and numeric modeling are widely used, however matching such data with properties’ measurements for industrial nanocomposites requires a link to be established between experimental and modeling length scales. In this work a computer code was developed to create a model composite structure with a predefined distribution probability of inclusions using NVIDIA CUDA GPGPU approach. The code is capable of randomly populating and analyzing samples of the typical size of microphotographs used for experimental characterization and typical nanoinclusions’ concentrations avoiding unphysical intersections and thus allow correlating the results of both optical characterization and statistical computer modeling. The initial probability distribution can be taken from experimental samples and further varied to investigate the effect of distribution on a desired property. Application to study the effect of carbon nanotubes and carbon nanofibers in a polymer matrix on the composite electrical and mechanical properties is discussed.FEDER - Programa Operacional Factores de Competitividade (COMPETE)Fundação para a Ciência e a Tecnologia (FCT) - CONC-REEQ/443/EEI/2005, PEst-C-FIS/UI607/2011-201

Strain mapping at the micro-scale in hierarchical polymer composites with aligned carbon nanotube grafted fibers

For the first time, micro-scale digital image correlation (μDIC) is investigated for measurement of strain fields in hierarchical fiber-reinforced composites. The methodology is developed on an exemplary alumina fiber/epoxy composite laminate with aligned carbon nanotubes (A-CNTs) grown on fibers. Utilizing environmental scanning electron microscopy and nano-scale random speckle patterns, sufficient precision is achieved to detect the influence of the A-CNTs on the deformation field around the fibers. Debonded regions at the fiber/matrix interface with openings as small as 35 nm could be detected. μDIC could identify the propagation of the debonded region based on the non-linear increase of the opening. The image correlation uncertainty in the displacement analysis is estimated to be below 5 nm. The experimental results are validated by computational analysis performed on the region of interest. For this, an advanced model with two scales of reinforcement (microscopic fibers and nanotubes) and boundary conditions taken from the experiment is used. As verified by the model, A-CNTs are found to constrain matrix deformation in their longitudinal direction. Keywords: Digital image correlation (DIC); Scanning electron microscopy (SEM); Carbon nanotubes; Mechanical properties; Finite element analysis (FEA