Asymmetrical flow field-flow fractionation in the study of water-soluble macromolecules

Asymmetrical flow field-flow fractionation (AsFlFFF) was constructed, and its applicability to industrial, biochemical, and pharmaceutical applications was studied. The effect of several parameters, such as pH, ionic strength, temperature and the reactants mixing ratios on the particle sizes, molar masses, and the formation of aggregates of macromolecules was determined by AsFlFFF. In the case of industrial application AsFlFFF proved to be a valuable tool in the characterization of the hydrodynamic particle sizes, molar masses and phase transition behavior of various poly(N-isopropylacrylamide) (PNIPAM) polymers as a function of viscosity and phase transition temperatures. The effect of sodium chloride salt and the molar ratio of cationic and anionic polyelectrolytes on the hydrodynamic particle sizes of poly (methacryloxyethyl trimethylammonium chloride) and poly (ethylene oxide)-block-poly (sodium methacrylate) and their complexes were studied. The particle sizes of PNIPAM polymers, and polyelectrolyte complexes measured by AsFlFFF were in agreement with those obtained by dynamic light scattering. The molar masses of PNIPAM polymers obtained by AsFlFFF and size exclusion chromatography agreed also well. In addition, AsFlFFF proved to be a practical technique in thermo responsive behavior studies of polymers at temperatures up to about 50 oC. The suitability of AsFlFFF for biological, biomedical, and pharmaceutical applications was proved, upon studying the lipid-protein/peptide interactions, and the stability of liposomes at different temperatures. AsFlFFF was applied to the studies on the hydrophobic and electrostatic interactions between cytochrome c (a basic peripheral protein) and anionic lipid, and oleic acid, and sodium dodecyl sulphate surfactant. A miniaturized AsFlFFF constructed in this study was exploited in the elucidation of the effect of copper (II), pH, ionic strength, and vortexing on the particle sizes of low-density lipoproteins.Väitöstyössä valmistettiin asymmetrinen virtauskenttävirtausfraktiointi(AsFlFFF)laitteisto ja tutkittiin sen soveltuvuutta teollisten, biokemiallisten ja farmaseuttisten näytteiden analysointiin. Laitteistolla tutkittiin useiden muuttujien kuten pH:n, ionivahvuuden, lämpötilan ja reaktanttien sekoitussuhteen vaikutusta tutkittavan näytteen hiukkaskokoon, moolimassaan sekä aggregaatioon. Teollisten näytteiden kohdalla AsFlFFF osoittautui tehokkaaksi työkaluksi poly(N-isopropyyliakryyliamidin) (PNIPAM) hydrodynaamisen hiukkaskoon, moolimassan sekä faasinmuutoskäyttäytymisen määrityksessä, kun ajoliuoksen viskositeettia ja lämpötilaa vaihdeltiin. Tutkittiin myös natriumkloridin sekä eri moolisuhteissa lisättyjen kationisten ja anionisten polyelektrolyyttien vaikutusta poly(metakryloetyylitrimetyyliammoniumkloridin) ja poly(natriummetakrylaatti) - poly(etyleenioksidi) -blokkikopolymeerin sekä näiden välisten kompleksien hydrodynaamiseen hiukkaskokoon. AsFlFFF:llä PNIPAM- polymeerinäytteille saadut hiukkaskoot eivät poikenneet vastaavista dynaamisella valonsironnalla saaduista tuloksista. Suuria eroja ei havaittu myöskään AsFlFFF:llä ja kokoekskluusiokromatografialla PNIPAM-näytteille määritetyissä moolimassoissa. AsFlFFF osoittautui käytännölliseksi tekniikaksi lämpöherkkien polymeerien tutkimuksessa toimittaessa alle 50 oC lämpötiloissa. AsFlFFF:n käyttökelpoisuus biologisiin, biolääketieteellisiin ja farmaseuttisiin sovelluksiin osoitettiin tutkimalla lipidi-proteiini/peptidi vuorovaikutuksia ja liposomien stabiilisuutta eri lämpötiloissa. Menetelmällä tutkittiin anionisen lipidin, oleiinihapon sekä natriumdodekyylisulfaatin ja sytosomi-C:n välillä ilmeneviä hydrodynaamisia ja sähköstaattisia vuorovaikutuksia. Työn yhteydessä rakennettua miniatyrisoitua AsFlFFF-kanavaa käytettiin tutkittaessa kupari(II):n, ionivahvuuden sekä pyörresekoituksen (vortexing) alhaisen tiheyden lipoproteiinin (LDL) partikkelikokoon aiheuttamia muutoksia

A Nonparametric Bayesian Approach to Estimating Malaria Prophylactic Effect After Two Treatments

Abstract: Two treatment regimens for malaria are compared in their abilities to cure and combat reinfection. Bayesian analysis techniques are used to compare two typical treatment therapies for uncomplicated malaria in children under five years, not only in their power to resist recrudescence, but also how long they can postpone recrudescence or reinfection in case of failure. We present a new way of analysing this type of data using Markov Chain Monte Carlo techniques. This is done using data from clinical trials at two different centres. The results which give the full posterior distributions show that artemisinin-based combination therapy is more efficacious than sulfadoxine-pyrimethamine. It both reduced the risk of recrudescence and delayed the time until recrudescence

Risk factors associated with asbestos-related diseases: results of the asbestos surveillance programme Aachen

The aim of this study was to examine the association between workplace exposure to asbestos and risk factors for developing related chronic respiratory diseases, using the analysis of a cohort of 8,582 formerly asbestos-exposed workers, as well as to assess the grade value of three risk categories used for a focused surveillance procedure. The results showed that the participants who were aged over 65 (OR and 95% CI: 11.47 [5.48-23.99]) and active smokers (OR and 95% CI: 9.48 [4.07-22.09]), were at a significantly high risk for developing lung cancer. The risk of developing benign lesions of the lung or pleura (BLLP) was almost 6-times higher (OR and 95% CI: 5.76 [4.7-7]) for the age group over 65. The risk of developing mesothelioma was influenced by exposure duration (OR and 95% CI: 4.36 [1-19.01]); and for the age group over 65 (OR and 95% CI: 4.58 [1.86-11.27]). The study has demonstrated that the use of risk categories based on a combination of risk factors (age, smoking status, and duration of exposure) could be advantageous for planning the target health surveillance programmes

Employment Status and Inequalities in Self-Reported Health

Background: The aim of this study was to investigate the impact of employment status on self-reported health in Gävleborg County.Methods: The study used data from the 2010 Health in Equal terms survey, a cross-sectional survey carried out in Gävleborg County in Sweden. A total of 4,245 individuals, aged 16–65 years were included in the analysis. Descriptive and logistic regression analyses were used to assess the relationship between employment status and self-reported healthResults: People who were outside the labour market had odds of poor health of 2.64 (Cl 2.28–3.05) compared to their employed counterparts. Controlling for other covariates reduced the risk slightly to 2.10 (1.69-2.60) but remained statistically significant. In addition, other variables were associated with self-reported poor health Conclusion: This study found a statistically significant association between being outside the labour market and poor self-reported health. The relation was explained partially by socio-economic and demographic variables. Further studies are needed to further investigate the observed relationships. Longitudinal studies are needed to further investigate the observed relationship. Policy-makers within the Gävleborg County need to pay attention to the health status of those out of work, especially during times of combined economic and labour market fluctuations.   Results of the study suggest the need to pay attention to the health status of those outside the labour market especially during times of economic hardship

Inventaire parasitologique de l'Ethiopie : Helminthes des zébus adultes de la région de Kofélé (Arussi)

Les auteurs dressent la liste des helminthes recueillis à l'autopsie d'un lot de zébus adultes originaires de la région de Kofélé (Sud de la Province de l'Arussi, Ethiopie). Ils observent, dans le tractus digestif et dans le foie, la présence de nombreux Trématodes et Nématodes fréquemment associés entre eux. Il en résulte un polyparasitisme qui, dans 20 p. 100 des cas environ, s'avère particulièrement grave. Par ailleurs, ils retrouvent, là encore, les 2 zoonoses majeures si répandues en Ethiopie: la ladrerie à Cysticercus bovis avec un taux d'infestation de 14,6 p. 100 et l'echinococcose à Echinococcus polymorphus qui affecte plus de 50 p. 100 des animaux autopsiés et provoque parfois leur mort par cachexi

Geographic Differentials in Mortality of Children in Mozambique: Their Implications for Achievement of Millennium Development Goal 4

In the light of Mozambique's progress towards the achievement of Millennium Development Goal 4 of reducing mortality of children aged less than five years (under-five mortality) by two-thirds within 2015, this study investigated the relationship between the province of mother's residence and under-five mortality in Mozambique, using data from the 2003 Mozambican Demographic and Health Survey. The analyses included 10,326 children born within 10 years before the survey. Results of univariate and multivariate analyses showed a significant association between under-five mortality and province (region) of mother's residence. Children of mothers living in the North provinces (Niassa, Cabo Delgado, and Nampula) and the Central provinces (Zambezia, Sofala, Manica, and Tete) had higher risks of mortality than children whose mothers lived in the South provinces, especially Maputo province and Maputo city. However, controlling for the demographic, socioeconomic and environmental variables, the significance found between the place of mother's residence and under-five mortality reduced slightly. This suggests that other variables (income distribution and trade, density of population, distribution of the basic infrastructure, including healthcare services, climatic and ecologic factors), which were not included in the study, may have confounding effects. This study supports the thought that interventions aimed at reducing under-five mortality should be tailored to take into account the subnational/regional variation in economic development. However, research is warranted to further investigate the potential determinants behind the observed differences in under-five mortality

Conformational changes of apoB-100 in SMase-modified LDL mediate formation of large aggregates at acidic pH

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Interaction of phospholipid transfer protein with human tear fluid mucins

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