Tetrabutylammonium methacrylate as a novel receptor for selective extraction of sulphonylurea drugs from biological fluids using molecular imprinting

Glibenclamide (GLIB), an oral antidiabetic medication of the sulphonylurea drugs family, was stoichiometrically imprinted using tetrabutylammonium methacrylate as the functional monomer, for the first time in molecular imprinting, and utilising the sulphonylurea affinity for carboxylate anions. Solution association between the drug and the novel functional monomer was studied by 1H-NMR titrations, whereby evidence of sulphonylurea deprotonation followed by the formation of “narcissistic” GLIB dimers was found when tested in CDCl3, while an affinity constant in excess of 105 L mol-1 was measured in DMSO-d6. Detailed analysis of GLIB binding on the subsequently prepared imprinted and non-imprinted polymers confirmed deactivation of binding sites by exchange of a proton between GLIB and methacrylate, followed by extraction of the tetrabutylammonium counterion from the polymer matrix, resulting in overall reduced binding capacities and affinities by the imprinted material under equilibrium conditions. An optimised MI-SPE protocol, which included a binding site re-activation step, was developed for the extraction of GLIB from blood serum, whereby recoveries of up to 92.4% were obtained with exceptional sample clean-up.

Diffusion coefficients in dense and supercritical fluids

Os coeficientes de difusão (D 12) são propriedades fundamentais na investigação e na indústria, mas a falta de dados experimentais e a inexistência de equações que os estimem com precisão e confiança em fases comprimidas ou condensadas constituem limitações importantes. Os objetivos principais deste trabalho compreendem: i) a compilação de uma grande base de dados para valores de D 12 de sistemas gasosos, líquidos e supercríticos; ii) o desenvolvimento e validação de novos modelos de coeficientes de difusão a diluição infinita, aplicáveis em amplas gamas de temperatura e densidade, para sistemas contendo componentes muito distintos em termos de polaridade, tamanho e simetria; iii) a montagem e teste de uma instalação experimental para medir coeficientes de difusão em líquidos e fluidos supercríticos. Relativamente à modelação, uma nova expressão para coeficientes de difusão a diluição infinita de esferas rígidas foi desenvolvida e validada usando dados de dinâmica molecular (desvio relativo absoluto médio, AARD = 4.44%) Foram também estudados os coeficientes de difusão binários de sistemas reais. Para tal, foi compilada uma extensa base de dados de difusividades de sistemas reais em gases e solventes densos (622 sistemas binários num total de 9407 pontos experimentais e 358 moléculas) e a mesma foi usada na validação dos novos modelos desenvolvidos nesta tese. Um conjunto de novos modelos foi proposto para o cálculo de coeficientes de difusão a diluição infinita usando diferentes abordagens: i) dois modelos de base molecular com um parâmetro específico para cada sistema, aplicáveis em sistemas gasosos, líquidos e supercríticos, em que natureza do solvente se encontra limitada a apolar ou fracamente polar (AARDs globais na gama 4.26-4.40%); ii) dois modelos de base molecular biparamétricos, aplicáveis em todos os estados físicos, para qualquer tipo de soluto diluído em qualquer solvente (apolar, fracamente polar e polar). Ambos os modelos dão origem a erros globais entre 2.74% e 3.65%; iii) uma correlação com um parâmetro, específica para coeficientes de difusão em dióxido de carbono supercrítico (SC-CO2) e água líquida (AARD = 3.56%); iv) nove correlações empíricas e semi-empíricas que envolvem dois parâmetros, dependentes apenas da temperatura e/ou densidade do solvente e/ou viscosidade do solvente. Estes últimos modelos são muito simples e exibem excelentes resultados (AARDs entre 2.78% e 4.44%) em sistemas líquidos e supercríticos; e v) duas equações preditivas para difusividades de solutos em SC-CO2, em que os erros globais de ambas são inferiores a 6.80%. No global, deve realçar-se o facto de os novos modelos abrangerem a grande variedade de sistemas e moléculas geralmente encontrados. Os resultados obtidos são consistentemente melhores do que os obtidos com os modelos e abordagens encontrados na literatura. No caso das correlações com um ou dois parâmetros, mostrou-se que estes mesmos parâmetros podem ser ajustados usando um conjunto muito pequeno de dados, e posteriormente serem utilizados na previsão de valores de D 12 longe do conjunto original de pontos. Uma nova instalação experimental para medir coeficientes de difusão binários por técnicas cromatográficas foi montada e testada. O equipamento, o procedimento experimental e os cálculos analíticos necessários à obtenção dos valores de D 12 pelo método de abertura do pico cromatográfico, foram avaliados através da medição de difusividades de tolueno e acetona em SC-CO2. Seguidamente, foram medidos coeficientes de difusão de eucaliptol em SC-CO2 nas gamas de 202 – 252 bar e 313.15 – 333.15 K. Os resultados experimentais foram analisados através de correlações e modelos preditivos para D12.

Multilayered non-invasive temperature estimation from backscattered ultrasound

Roughly one in four breast cancer survivors report some degree of arm oedema. Lymphoedema is a build-up of excess lymph fluids in the tissues. Persistent lymphoedema leads to pain, diminished limb function, increased risk of infection, soft tissue fibrosis, and severe cases can be grossly disfiguring. From a mechanics perspective, the lymphoedemous tissue may be thought of as a two phase composite, consisting of both fluid and solid phases. Here we discuss the use of composites mixture theory to model the mechanics of lymphoedemous tissues. By treating the tissue as a fluid-solid composite, rules-of-mixtures may be used to estimate the effective moduli in terms of the properties of the individual components and their respective volume fractions in these two states.

Efficient non-linear data assimilation in geophysical fluid dynamics

New ways of combining observations with numerical models are discussed in which the size of the state space can be very large, and the model can be highly nonlinear. Also the observations of the system can be related to the model variables in highly nonlinear ways, making this data-assimilation (or inverse) problem highly nonlinear. First we discuss the connection between data assimilation and inverse problems, including regularization. We explore the choice of proposal density in a Particle Filter and show how the ’curse of dimensionality’ might be beaten. In the standard Particle Filter ensembles of model runs are propagated forward in time until observations are encountered, rendering it a pure Monte-Carlo method. In large-dimensional systems this is very inefficient and very large numbers of model runs are needed to solve the data-assimilation problem realistically. In our approach we steer all model runs towards the observations resulting in a much more efficient method. By further ’ensuring almost equal weight’ we avoid performing model runs that are useless in the end. Results are shown for the 40 and 1000 dimensional Lorenz 1995 model.

A general method for finding extremal states of Hamiltonian dynamical systems, with applications to perfect fluids

In addition to the Hamiltonian functional itself, non-canonical Hamiltonian dynamical systems generally possess integral invariants known as ‘Casimir functionals’. In the case of the Euler equations for a perfect fluid, the Casimir functionals correspond to the vortex topology, whose invariance derives from the particle-relabelling symmetry of the underlying Lagrangian equations of motion. In a recent paper, Vallis, Carnevale & Young (1989) have presented algorithms for finding steady states of the Euler equations that represent extrema of energy subject to given vortex topology, and are therefore stable. The purpose of this note is to point out a very general method for modifying any Hamiltonian dynamical system into an algorithm that is analogous to those of Vallis etal. in that it will systematically increase or decrease the energy of the system while preserving all of the Casimir invariants. By incorporating momentum into the extremization procedure, the algorithm is able to find steadily-translating as well as steady stable states. The method is applied to a variety of perfect-fluid systems, including Euler flow as well as compressible and incompressible stratified flow.

Start-up rheometry of highly polydisperse magnetorheological fluids: experiments and simulations

An extensive experimental and simulation study is carried out in conventional magnetorheological fluids formulated by dispersion of mixtures of carbonyl iron particles having different sizes in Newtonian carriers. Apparent yield stress data are reported for a wide range of polydispersity indexes (PDI) from PDI = 1.63 to PDI = 3.31, which for a log-normal distribution corresponds to the standard deviation ranging from to . These results demonstrate that the effect of polydispersity is negligible in this range in spite of exhibiting very different microstructures. Experimental data in the magnetic saturation regime are in quantitative good agreement with particle-level simulations under the assumption of dipolar magnetostatic forces. The insensitivity of the yield stresses to the polydispersity can be understood from the interplay between the particle cluster size distribution and the packing density of particles inside the clusters.

Integrable maps with non-trivial topology: application to divertor configurations

We explore a method for constructing two-dimensional area-preserving, integrable maps associated with Hamiltonian systems, with a given set of fixed points and given invariant curves. The method is used to find an integrable Poincare map for the field lines in a large aspect ratio tokamak with a poloidal single-null divertor. The divertor field is a superposition of a magnetohydrodynamic equilibrium with an arbitrarily chosen safety factor profile, with a wire carrying an electric current to create an X-point. This integrable map is perturbed by an impulsive perturbation that describes non-axisymmetric magnetic resonances at the plasma edge. The non-integrable perturbed map is applied to study the structure of the open field lines in the scrape-off layer, reproducing the main transport features obtained by integrating numerically the magnetic field line equations, such as the connection lengths and magnetic footprints on the divertor plate.

Shear- free perfect fluids with solenoidal magnetic curvature and a γ-law equation of state

We show that shear-free perfect fluids obeying an equation of state p = (γ − 1)μ are non-rotating or non-expanding under the assumption that the spatial divergence of the magnetic part of the Weyl tensor is zero.

Bioassay detects soluble MAdCAM-1 in body fluids

Mucosal addressin cell adhesion molecule (MAdCAM-1) is a key player in mediating the infiltration of leucocytes into chronically inflamed tissues. Five anti-MAdCAM-1 monoclonal antibodies (mAb), designated 17F5, 201F7, 314G8, 377D10 and 355G8, were generated by fusion of P3 × 63Ag8.653 myeloma cells with spleen cells from BALB/c mice immunized with recombinant human MAdCAM-1-Fc. The latter four mAb recognize the ligand-binding first Ig domain, and block T -cell adhesion to MAdCAM-1. The non-blocking mAb 17F5 recognizes the mucin domain. Extensive analysis of a large panel of paraffin-embedded human tissues revealed that the 314G8 mAb detected MAdCAM-1 on venules in the spleen and small intestine. MAdCAM-1 was strongly expressed in the synovium of osteoarthritis patients, predominantly on the endothelial lining of blood vessels, but also within the vessel lumen. An ELISA, based on mAb 377D10 and 355G8, was developed to determine whether soluble MAdCAM-1 was present in body fluids, and to measure the levels present. The assay detected soluble MAdCAM-1 in the serum and urine of healthy donors, at levels similar to those of soluble forms of the related CAM, ICAM-1 and VCAM-1. The anti-MAdCAM-1 antibodies and assay developed here may be useful therapeutically in the treatment of inflammation in humans. Similarly, they may be useful diagnostically to monitor the presence and levels of MAdCAM-1.

Symbolic computation and perfect fluids in general relativity

Focuses on two areas within the field of general relativity. Firstly, the history and implications of the long-standing conjecture that general relativistic, shear-free perfect fluids which obey a barotropic equation of state p = p(w) such that w + p = 0, are either non-expanding or non-rotating. Secondly the application of the computer algebra system Maple to the area of tetrad formalisms in general relativity.

Shear-free perfect fluids with a solenoidal magnetic curvature

We investigate shear-free perfect fluid solutions of the Einstein field equations where the fluid pressure satisfies a barotropic equation of state and the spatial divergence of the magnetic part of the Weyl tensor is zero. We prove, with the exception of certain quite restricted special cases within the class of solutions in which there exists a Killing vector aligned with the vorticity and for which the magnitude of the vorticity ω is not a function of the matter density μ alone, that such a fluid is either non-rotating or non-expanding. In the restricted cases the equation of state must satisfy an over-determined differential system.

Natural convection in domed porous enclosures : non-darcian flow

The natural-convection flow and associated heat transfer in a fluid-saturated porous medium have been investigated using the generalized porous medium approach for a dome-shaped enclosure. Many new features have been predicted with the connective heat transfer and the shape of the top dome cover. The solutions are obtained for a wide range of Darcy and Rayleigh numbers for different offsets and eccentricities of the top dome covers. The detailed parametric study reveals that there is a significant change in heat transfer rate when the offset is between 0.2 and 0.4. Different shapes of conic section, such as circular, elliptical, parabolic, and hyperbolic are used for the top dome cover, and their effects on natural convection and heat transfer rates are studied.

Nutrient and core and non-core food intake of Australian schoolchildren differs on school days compared to non-school days.

Overall the diets of Australian schoolchildren are suboptimal, but differences in nutrient and food intake on school versus non-school days have not been assessed. The aim of this study was to examine differences in nutrient and core and non-core food intake on school days versus non-school days in Australian schoolchildren aged 6-16 years. Cross-sectional analysis of the 2007 Australian Children's Nutrition and Physical Activity Survey. Dietary intake was assessed via one 24-h dietary recall. A school day was defined as Monday-Friday, a non-school day included Saturday, Sunday and public/school holidays. Independent t-tests and χ(2) tests were used to assess differences in continuous and categorical variables, respectively. Multiple linear and logistic regression was used to adjust for confounders. Forty-eight per cent of recalls were completed on a non-school day. On non-school days primary schoolchildren aged 6-11 years (n = 1334) and secondary schoolchildren aged 12-16 years (n = 1362) had significantly higher absolute intakes of sugars, total fat and saturated fat (all P < 0.05). In addition the energy density of foods consumed was greater (P < 0.001), but there was no difference in the energy density of fluids. The sodium density of the diet did not differ across day types. On non-school days, total core food intake was ~30% higher and children were more likely to consume sugar-sweetened beverages, fried potatoes and take-away pizzas and burgers (all P < 0.05). Important differences in the intake of sugar, total fat, and saturated fat and noncore foods exist on non-school days compared to school days in Australian schoolchildren. To improve the diets of schoolchildren there is scope for strategies that target non-school day eating practices.

Durable non-wetting fabrics: the preparation and application

Air-permeable, super-liquid-repellent fabrics show strong resistance to various liquid fluids and have self-cleaning, anti-sticking, and anti-contaminating functions, which are very useful for development of function clothing. However, most of the liquid repellent fabrics are poor in durability.This book elaborated the development of durable super-liquid-repellent fabrics and explore novel property of liquid-repellent fabrics. It has resulted in two novel concepts to prepare durable liquid repellent fabrics. By combining liquid repellent with liquid absorbing features on different sides of single layer fabric, a novel directional-fluid transport property was observed.

Structure formation in the presence of dark energy perturbations

We study non-linear structure formation in the presence of dark energy. The influence of dark energy on the growth of large-scale cosmological structures is exerted both through its background effect on the expansion rate, and through its perturbations. In order to compute the rate of formation of massive objects we employ the spherical collapse formalism, which we generalize to include fluids with pressure. We show that the resulting non-linear evolution equations are identical to the ones obtained in the pseudo-Newtonian approach to cosmological perturbations, in the regime where an equation of state serves to describe both the background pressure relative to density, and the pressure perturbations relative to the density perturbations. We then consider a wide range of constant and time-dependent equations of state (including phantom models) parametrized in a standard way, and study their impact on the non-linear growth of structure. The main effect is the formation of dark energy structure associated with the dark matter halo: non-phantom equations of state induce the formation of a dark energy halo, damping the growth of structures; phantom models, on the other hand, generate dark energy voids, enhancing structure growth. Finally, we employ the Press-Schechter formalism to compute how dark energy affects the number of massive objects as a function of redshift (number counts).