Analysis Using Size Exclusion Chromatography of poly(N-isopropyl acrylamide) using Methanol as an Eluent

YesSize Exclusion Chromatography is traditionally carried out in either aqueous or non-polar solvents. A system to present molar mass distributions of polymers using methanol as a mobile phase is presented. This is shown to be a suitable system for determining the molar mass distributions poly(N-isopropylacrylamide)s (PNIPAM); a polymer class that is often difficult to analyze by size exclusion chromatography. DOSY NMR was used to provide intrinsic viscosity data that was used in conjunction with a viscometric detector to provide absolute calibration. Then the utility of the system was shown by providing the absolute molar mass distributions of dispersed highly branched PNIPAM with biologically functional end groups.Wellcome Trus

Development of a vascular graft blood flow control system

Dializa je postopek, pri katerem se zaradi okvarjenega delovanja ledvic poskuša s pomočjo dializnega aparata iz krvnega obtoka izločiti čim več odpadnih produktov metabolizma. Zaradi pogostega vbadanja z iglo in nizkega pretoka krvi se uporablja žilni vsadek, ki arterijo neposredno poveže z veno v roki. Zaradi tega se vena razširi. Vendar pa je ta razširitev zaželena le med dializo. V praksi se lahko vena trajno prekomerno razširi, kar povzroča težave. V diplomskem delu je predstavljena zasnova in izdelava koncepta krmilnega sistema, ki krmili odprtje žilnega vsadka. Potrebna je izbira ustreznega aktuatorja, konstruiranje in izdelava mehanizma s spremenljivim premerom, na katerega lahko aktuator deluje. Delovanje celotnega sistema pa se krmili s pomočjo mikrokrmilnika Arduino, ki omogoča brezžično komunikacijo s pametnim telefonom. Izdelana je bila tudi ustrezna aplikacija za mobilno napravo s programskim jezikom Xamarin/C#.Dialysis is a procedure that filters as much waste products of metabolism as possible, due to kidney disease. Because of repeatable use of syringes and low blood flow of the blood vessels, an arteriovenous access is created. Because of this, the vein increases in its diameter, which is wanted only during dialysis. In practice, the diameter of the vein can increase dramatically, which is the main problem. In this thesis, the development of a control system concept for controlling blood flow of an arteriovenous graft is demonstrated. For the development, the correct linear actuator with an adjustable stroke is needed. Furthermore, a mechanism for squeezing the graft needs to be created and analyzed. The whole system is controlled by an Arduino microcontroller, that supports wireless communication. Furthermore, an application for a mobile phone was created with Xamarin/C# programming language

Using human biomonitoring for the risk assessment of polycyclic aromatic hydrocarbons in occupational exposures

Abstracts publicado em: Toxicology Letters. 2019;314S1:S76.Background and Purpose: The Human Biomonitoring Initiative (HBM4EU) is a joint effort of 28 countries, the European Environment Agency and the European Commission, co-funded under Horizon 2020. HBM4EU is generating evidence of the current exposure of European citizens to chemicals and the possible health effects in order to assess the associated risks and support policy making towards human health protection. Polycyclic aromatic hydrocarbons (PAH) were considered one of the 1st priority substance groups to be addressed. In the scope of this project, the present work aimed to evaluate the added value of human biomonitoring (HBM) for the PAH risk assessment process, in the case of occupational exposure. Methods: An extensive literature search was performed to identify scientific papers published between 2008 and 2018 that included air monitoring and HBM data in several occupational settings based in Europe. Among them, those papers presenting urinary 1-hydroxypyrene (1-OHP) quantification - the most common exposure biomarker of pyrene and a surrogate for exposure to PAHs mixtures - were selected. Based on the 1-OHP values the excess lifetime cancer risk (ELCR) for workers, concerning lung cancer, was estimated following the ECHA recent approach (https://echa.europa.eu/fi/applying-for-authorisation/evaluating-applications). ELCR values calculated using air and HBM data were compared. Results: Based on the criteria described, only 7 out of 28 papers were considered for ELCR estimation. Overall, high ELCR values were estimated (several values higher than 10-4). Moreover, for some studies (3 out of 7) the ELCR estimation using HBM data yielded values higher than those estimated from air monitoring data. This might indicate that, for those specific workplaces, transdermal absorption or even hand-mouth exposure can have an important role in the total exposure to PAH and that the HBM data allows a more accurate PAH exposure assessment. Nevertheless, these findings should be interpreted with caution, since ELCR estimates from air monitoring data are based on Benzo[a]pyrene (BaP) concentrations while HBM-based ELCR determination uses urinary 1-OHP concentration that reflects exposure not only to BaP but to all PAHs, irrespectively of sources or routes of exposure. This work claims attention for two main aspects, namely: i) the exposure levels are still high in some occupational settings and ii) there is a need for developing new occupational studies, applying a set of exposure biomarkers or a more specific biomarker for BaP exposure, which would allow a better ELCR estimation for exposed workers.The HBM4EU project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 733032.info:eu-repo/semantics/publishedVersio

The direct determination of partial molar volumes and reaction volumes in ultra-dilute non-reactive and reactive multi-component systems using a combined spectroscopic and modified response surface model approach.

Dalton transactions (Cambridge, England : 2003)121505-151