Quantitative microchip capillary electrophoresis for inorganic ion analysis at the point of care

This thesis describes the development of a microchip capillary electrophoresis system for measuring inorganic ions in samples at the point of care. The analysis of inorganic ions in whole blood, specifically lithium to monitor the treatment of patients suffering from\ud manic depression is investigated

Field measurements of snow-drift threshold and mass fluxes, and related model simulations

Field measurements were carried out to calculate the threshold friction velocity for snow saltation, and mass fluxes during snow drift. The wind was measured in three components by an ultrasonic anemometer, and the mass fluxes were determined using an optical sensor (‘snow particle counter'), acoustic sensors (‘Flowcapt') and mechanical traps. The threshold friction velocity was found to be correlated to the grain size (R2=0.75). The mass flux measurements were compared with numerical simulations of snow drift, and it was demonstrated that the maximum snow transport takes place at shear stress values of roughly two times the average shear stress over 20 min. By implementing a probability distribution for the shear stress the mass flux was simulated with only the mean measured value of the shear stress as input. This procedure enables the future use of the numerical model for operational application

DNA damage responses in mammalian cells : focus on signaling and repair

Genetic alterations such as mutations, genomic rearrangements and aneuploidy, are commonly observed in tumors. To counteract this cells have multiple genome maintenance and surveillance systems to minimize the rate at which genomic alterations arise. The aim of the thesis is to gain understanding of processes and pathways that contribute to the maintenance of genome stability and to establish how defects in these processes and pathways abrogate the DNA damage response and consequently may promote genomic instability and development of cancer. The work described in this thesis addresses various aspects of the cellular response of mammalian cells to DNA damaging agents including changes in post translational modifications that occur after genotoxic stress. The role of poly-adenosyl ribose modification in nucleotide excision repair is investigated and found to be important for the recruitment of a chromatin remodeling protein and repair. Phosphoproteomic analysis identified changes in the global phosphorylation state of proteins following genotoxic stress. Key kinases responding to DNA damage are ATR and related kinases. A detailed study into the requirements for ATR activation after UV exposure indicates that at least two distinct modes of activation exist. Finally we describe the profound sensitivity of Cornelia de Lange Syndrome cells to DNA damage.UBL - phd migration 201

Bone and joint disorders: screening and early clinical drug development

Bone and joint disorders have an enormous personal- and societal impact. Diagnosis and treatment of these disorders are most efficient if targeted screening, accurate diagnosis, and targeted treatment are available. To enable targeted screening, the population at risk must be well-defined, and categorized if required. Subsequently, screening- and diagnostic methods must have good, or excellent predictive value and finally, treatment must target the disease, thus spare healthy tissues and processes and thereby avoid adverse events.The aim of this thesis is to gain new insights about the diagnostic process- and treatment of pathological conditions of the bone and joints, namely male urological cancer-induced bone loss and inflammatory arthritis.LUMC / Geneeskund

Integrated Lithographic Molding for Microneedle-Based Devices

This paper presents a new fabrication method consisting of lithographically defining multiple layers of high aspect-ratio photoresist onto preprocessed silicon substrates and release of the polymer by the lost mold or sacrificial layer technique, coined by us as lithographic molding. The process methodology was demonstrated fabricating out-of-plane polymeric hollow microneedles. First, the fabrication of needle tips was demonstrated for polymeric microneedles with an outer diameter of 250 mum, through-hole capillaries of 75-mum diameter and a needle shaft length of 430 mum by lithographic processing of SU-8 onto simple v-grooves. Second, the technique was extended to gain more freedom in tip shape design, needle shaft length and use of filling materials. A novel combination of silicon dry and wet etching is introduced that allows highly accurate and repetitive lithographic molding of a complex shape. Both techniques consent to the lithographic integration of microfluidic back plates forming a patch-type device. These microneedle-integrated patches offer a feasible solution for medical applications that demand an easy to use point-of-care sample collector, for example, in blood diagnostics for lithium therapy. Although microchip capillary electrophoresis glass devices were addressed earlier, here, we show for the first time the complete diagnostic method based on microneedles made from SU-8

De gelukkige ontdekkingen van de beerput

Provincial Roman and Medieval Archaeology, colonial expansio

Verdiepen in warmer water: een modelstudie naar watertemperaturen en het effect van diepte

‘s Zomers zullen steeds vaker langere periodes van hitte gaan optreden. Wat heeft dit voor effect op de lokale watertemperatuur? En heeft het zin om waterpartijen te verdiepen? Met de Cool Water Tool is geprobeerd modelmatig greep te krijgen op deze vragen. De resultaten laten zien dat de watertemperaturen met klimaatverandering toenemen. Lokaal verdiepen heeft weinig effect op de gemiddelde watertemperatuur. Daarentegen neemt de lengte van de maximale aaneengesloten periode met watertemperaturen hoger dan 20 graden fors toe

Characterizing a thermostable Cas9 for bacterial genome editing and silencing

CRISPR-Cas9-based genome engineering tools have revolutionized fundamental research and biotechnological exploitation of both eukaryotes and prokaryotes. However, the mesophilic nature of the established Cas9 systems does not allow for applications that require enhanced stability, including engineering at elevated temperatures. Here we identify and characterize ThermoCas9 from the thermophilic bacterium Geobacillus thermodenitrificans T12. We show that in vitro ThermoCas9 is active between 20 and 70 °C, has stringent PAM-preference at lower temperatures, tolerates fewer spacer-protospacer mismatches than SpCas9 and its activity at elevated temperatures depends on the sgRNA-structure. We develop ThermoCas9-based engineering tools for gene deletion and transcriptional silencing at 55 °C in Bacillus smithii and for gene deletion at 37 °C in Pseudomonas putida. Altogether, our findings provide fundamental insights into a thermophilic CRISPR-Cas family member and establish a Cas9-based bacterial genome editing and silencing tool with a broad temperature range

Stabilizing single atom contacts by molecular bridge formation

Gold-molecule-gold junctions can be formed by carefully breaking a gold wire in a solution containing dithiolated molecules. Surprisingly, there is little understanding on the mechanical details of the bridge formation process and specifically on the role that the dithiol molecules play themselves. We propose that alkanedithiol molecules have already formed bridges between the gold electrodes before the atomic gold-gold junction is broken. This leads to stabilization of the single atomic gold junction, as observed experimentally. Our data can be understood within a simple spring model.Comment: 14 pages, 3 figures, 1 tabl