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| 2. |
- Beech, J. P., et al.
(författare)
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What do photons do to fluorescently stained DNA in confinement?
- 2013
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Ingår i: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013; Freiburg; Germany; 27 October 2013 through 31 October 2013. ; 1, s. 5-7
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Konferensbidrag (refereegranskat)abstract
- We have studied a selection of factors influencing the damage of DNA in nanochannels during fluorescence imaging. For cutting and nicking of DNA we show that the DNA is shortened during imaging. To avoid photodamage over the course of several hours of a typical experiment, we demonstrate the importance of an oxygen free gas to propel the buffer solution through the device. Finally, by varying the size of the channels, we show indications that higher DNA concentrations lead to higher rates of photodamage necessitating a balance between needs for highly stretched DNA and needs for long measurement times.
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| 3. |
- Cerbu, D., et al.
(författare)
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Vortex ratchet induced by controlled edge roughness
- 2013
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate theoretically and experimentally the generation of rectified mean vortex displacement resulting from a controlled difference between the surface barriers at the opposite borders of a superconducting strip. Our investigation focuses on Al superconducting strips where, in one of the two sample borders, a saw tooth-like array of micro-indentations has been imprinted. The origin of the vortex ratchet effect is based on the fact that (i) the onset of vortex motion is mainly governed by the entrance/nucleation of vortices and (ii) the current lines bunching produced by the indentations facilitates the entrance/nucleation of vortices. Only for one current direction the indentations are positioned at the side of vortex entry and the onset of the resistive regime is lowered compared to the opposite current direction. This investigation points to the relevance of ubiquitous border effects typically neglected when interpreting vortex ratchet measurements on samples with arrays of local asymmetric pinning sites.
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| 4. |
- Frykholm, Karolin, 1977, et al.
(författare)
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Probing physical properties of DNA-protein complexes using nanofluidic channels
- 2013
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Ingår i: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013; Freiburg; Germany; 27 October 2013 through 31 October 2013. - 9781632666246 ; 2, s. 1311-1313
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Konferensbidrag (refereegranskat)abstract
- We present the use of nanofluidic channels as a tool for determining physical properties of single DNA-protein complexes. By coating the nanochannels with a lipid bilayer we avoid sticking of proteins to the channel walls. RecA is a prokaryotic protein involved in recombination and DNA repair. We study filaments of RecA, bound to both double stranded (ds) and single stranded (ss) DNA. We determine the persistence length of RecA filaments on both dsDNA and ssDNA and obtain values in agreement with the literature. Neither the DNA nor the protein has to be attached to handles or surfaces, and the technique is directly transferable to Lab-on-a-Chip technologies for high throughput measurements in solution.
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| 5. |
- Motta, M., et al.
(författare)
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Enhanced pinning in superconducting thin films with graded pinning landscapes
- 2013
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 102:21
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Tidskriftsartikel (refereegranskat)abstract
- A graded distribution of antidots in superconducting a-Mo79Ge21 thin films has been investigated by magnetization and magneto-optical imaging measurements. The pinning landscape has maximum density at the sample border, decreasing linearly towards the center. Its overall performance is noticeably superior than that for a sample with uniformly distributed antidots: For high temperatures and low fields, the critical current is enhanced, whereas the region of thermomagnetic instabilities in the field-temperature diagram is significantly suppressed. These findings confirm the relevance of graded landscapes on the enhancement of pinning efficiency, as recently predicted by Misko and Nori.
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