Stressing reward: Does sex matter?

Acute stress beïnvloedt de manier waarop wij informatie over ons eigen functioneren verwerken, blijkt uit promotieonderzoek van Stella Banis. Zij vond in experimenten, waarin naast gedrag ook hersenactiviteit werd gemeten, dat proefpersonen in stresssituaties hun aandacht minder goed richtten op relevante informatie, en minder gevoelig waren voor feedback op hun prestaties. Dit is in overeenstemming met de theorie dat een verstoorde werking van juist deze functies een centrale rol speelt in de ontwikkeling van bepaalde stressgerelateerde stoornissen. Stressgerelateerde stoornissen, zoals depressie en verslaving, vormen een groot maatschappelijk probleem. Opmerkelijk is dat sommige van deze stoornissen vaker voorkomen bij vrouwen, terwijl andere vaker mannen treffen. Banis vond echter dat de effecten van stress op de verwerking van feedback grotendeels gelijk waren voor de vrouwen en mannen die deelnamen aan haar onderzoek. Eén van de aannames in het verklaren van sekseverschillen in stressgerelateerde stoornissen is dat bij vrouwen hormoonschommelingen een belangrijke rol spelen in het ontstaan van bepaalde stoornissen. Van vrouwen wordt vaak gedacht dat zij met name in de dagen voor hun menstruatie stressgevoeliger zijn dan anders. Dit idee werd echter niet bevestigd door een experiment van Banis, waaraan gezonde vrouwen tijdens twee fasen deelnamen. Een verhoogde stressgevoeligheid tijdens de premenstruele fase speelt mogelijk alleen een rol bij vrouwen met een premenstruele stemmingsstoornis. Wel vond Banis in haar onderzoek bewijs dat de menstruele fase van invloed is op de manier waarop vrouwen informatie over hun functioneren verwerken. In de dagen voor de eisprong waren vrouwen gevoeliger voor informatie over hun prestaties (doe ik het goed of niet?), ongeacht of er een beloning op het spel stond. In de dagen voor de menstruatie reageerden vrouwen sterker op beloningsprikkels

A Study on Magnetic Removal of Hexavalent Chromium from Aqueous Solutions Using Magnetite/Zeolite-X Composite Particles as Adsorbing Material

Toxic and heavy metals are considered harmful derivatives of industrial activities; they are not biodegradable and their accumulation in living organisms can become lethal. Among other heavy and toxic metals, chromium is considered hazardous, especially in the hexavalent (Cr6+) form. Numerous established studies show that exposure to Cr6+ via drinking water leads to elevated chromium levels in tissues, which may result in various forms of cancer. The purpose of this research is to synthesize magnetite/zeolite-X composite particles for the adsorption and magnetic removal of Cr6+ ions from aqueous solutions. Synthesis and characterization of such composite nanomaterials, along with an initial experimental evaluation of Cr6+ removal from water-based solution, are presented. Results show that zeolite-X is a very promising zeolite form, that when bound to magnetic nanoparticles can be used to trap and magnetically remove toxic ions from aqueous solutions

Design and Testing of a Disposable Flow Cuvette for Continuous Electroporation of a Bioreactor’s Initial Algae Cultivation

Electroporation is a technique applied both in biomedical and biotechnological fields which uses a high-voltage electric current to temporarily destabilize the plasma membrane of living cells, permitting the introduction of small molecules as well as nucleic acids into the cytosol. Besides viral and chemical transfections, this method is a common way to manipulate living cells. However, the majority of electroporation machines available on the market can only work using batch-based cuvettes treating only a few micrograms of cells. To transform cells in the order of several grams in the quickest possible way, it is necessary to use a continuous-flow method. In this work, we present the design, electric and fluid dynamics simulations, construction and testing of a flow cuvette that can adapt to standard electroporator systems. The flow cuvette connected with a peristaltic pump was able to successfully electroporate 20 mL of medium containing microalgae cells in less than 5 min. Microalgae Scenedesmus almeriensis cells were transfected with a fluorescent siRNA oligo as well as magnetically transformed by introducing magnetic nanoparticles in their cytoplasm. The flow cuvette presented here offers a valid tool for the high-throughput transformation/transfection/transfer of both prokaryotic and eukaryotic organisms, especially suitable for bioreactor cultivation and other industrial biotechnological contexts

Design and Testing of a Disposable Flow Cuvette for Continuous Electroporation of a Bioreactor’s Initial Algae Cultivation

Electroporation is a technique applied both in biomedical and biotechnological fields which uses a high-voltage electric current to temporarily destabilize the plasma membrane of living cells, permitting the introduction of small molecules as well as nucleic acids into the cytosol. Besides viral and chemical transfections, this method is a common way to manipulate living cells. However, the majority of electroporation machines available on the market can only work using batch-based cuvettes treating only a few micrograms of cells. To transform cells in the order of several grams in the quickest possible way, it is necessary to use a continuous-flow method. In this work, we present the design, electric and fluid dynamics simulations, construction and testing of a flow cuvette that can adapt to standard electroporator systems. The flow cuvette connected with a peristaltic pump was able to successfully electroporate 20 mL of medium containing microalgae cells in less than 5 min. Microalgae Scenedesmus almeriensis cells were transfected with a fluorescent siRNA oligo as well as magnetically transformed by introducing magnetic nanoparticles in their cytoplasm. The flow cuvette presented here offers a valid tool for the high-throughput transformation/transfection/transfer of both prokaryotic and eukaryotic organisms, especially suitable for bioreactor cultivation and other industrial biotechnological contexts

An innovative application of super-paramagnetic iron oxide nanoparticles for magnetic separation

In the last decades, iron oxide nanoparticle application has taken root in several technological fields, such as magnetic separation of biomolecules, biosensors, bio-fuel production, nano-devices and nano-adsorption. Various approaches can be found for the magnetic nanoparticle manufacturing. Among them a new technology to manufacture core-cell super-paramagnetic iron oxide nanoparticles (SPIONs), based on a vapour composition using single ion precursors, like cyclodextrines, has been recently developed. In this paper, we present the synthesis of functionalized SPIONs as well as the modelling for an innovative application of this magnetic nanotechnology. It consists on the use of SPIONs to trap target organic or inorganic molecules in a continuous-flow apparatus. SPIONs with proper ligands are immobilized on a magnetic surface. On that surface, the solution containing target molecules is circulated. We modelled the magnetic properties of the magnetic surface and SPIONs as well as the velocity of liquid needed in order to avoid removal of nanoparticles by the solution flow