arXiv subjects

Liselotte Jauffred

Publications and source records attributed to Liselotte Jauffred.

4 recordsLinked to original sources

arXiv2019

Effects and side-effects of plasmonic photothermal therapy in brain tissue

Heat generated from plasmonic nanoparticles can be utilized in plasmonic photothermal therapy. A combination of near-infrared laser and metallic nanoparticles are compelling for the treatment of brain cancer, due to their efficient light-to-heat conversion and bio-compatibility. However, one of the challenges of plasmonic photothermal therapy is to minimize the damage of the surrounding brain tissue. The adjacent tissue can be damaged as the results of either absorption of laser light, thermal conductivity, nanoparticles diffusing from the tumor, or a combination hereof. Hence, we still lack the full understanding about the light-tissue interaction and, in particular, the thermal response. We tested the temperature change in three different porcine cerebral tissues, i.e., the stem, the cerebrum, and the cerebellum, under laser treatment. We find that the different tissues have differential optical and thermal properties and confirm the enhancement of heating from adding plasmonic nanoparticles. Furthermore, we measure the loss of laser intensity through the different cerebral tissues and stress the importance of correct analysis of the local environment of a brain tumor.

physics.med-ph↗

arXiv2018

Why not use the thermal radiation for nanothermometry?

The measurement of temperature with nanoscale spatial resolution is an emerging new technology and it has important impact in various fields. An ideal nanothermometer should not only be accurate, but also applicable over a wide temperature range and under diverse conditions. Furthermore, the measurement time should be short enough to follow the evolution of the system. However, many of the existing techniques are limited by drawbacks such as low sensitivity and fluctuations of fluorescence. Therefore, Plank's law offers an appealing relation between the absolute temperature of the system under interrogation and the thermal spectrum. Despite this, thermal radiation spectroscopy is unsuitable for far-field nanothermometry, primarily because of the power loss in the near surroundings and a poor spatial resolution.

cond-mat.mes-hall↗

arXiv2018

Gender Bias in Nobel Prizes

Strikingly few Nobel laureates within medicine, natural and social sciences are women. Although it is obvious that there are fewer women researchers within these fields, does this gender ratio still fully account for the low number of female Nobel laureates? We examine whether women are awarded the Nobel Prizes less often than the gender ratio suggests. Based on historical data across four scientific fields and a Bayesian hierarchical model, we quantify any possible bias. The model reveals, with exceedingly large confidence, that indeed women are strongly under-represented among Nobel laureates across all disciplines examined.

stat.AP↗

arXiv2010

Quantum dots as handles for optical manipulation

Individual colloidal quantum dots can be optically trapped and manipulated by a single infrared laser beam operated at low laser powers. If the absorption spectrum and the emission wavelength of the trapping laser are appropriately chosen, the trapping laser light can act as a source for two-photon excitation of the trapped quantum dot. This eliminates the need for an additional excitation laser in experiments where individual quantum dots are used both as force transducers and for visualization of the system. To use quantum dots as handles for quantitative optical force transduction, it is crucial to perform a precise force calibration. Here, we present an Allan variance analysis of individual optically trapped quantum dots and show that the optimal measurement time for experiments involving individual quantum dots is on the order of 0.3 seconds. Due to their small size and strong illumination, quantum dots are optimal for single molecule assays where, optimally, the presence of the tracer particle should not dominate the dynamics of the system. As an example, we investigated the thermal fluctuations of a DNA tether using an individual colloidal quantum dot as marker, this being the smallest tracer for tethered particle method reported.

physics.optics↗