2017
Sarbak, Szymon; Sharma, Gargi; Joseph, Cecil S; Kucia, Weronika; Dobek, Krzysztof; Giles, Robert H; Dobek, Andrzej
Direct observation of the THz Kerr effect (TKE) in deionized, distilled and buffered (PBS) water Journal Article
In: Physical Chemistry Chemical Physics, vol. 19, no. 39, pp. 26749-26757, 2017.
Abstract | Links | BibTeX | Tagi:
@article{Sarbak2017,
title = {Direct observation of the THz Kerr effect (TKE) in deionized, distilled and buffered (PBS) water},
author = {Szymon Sarbak and Gargi Sharma and Cecil S Joseph and Weronika Kucia and Krzysztof Dobek and Robert H Giles and Andrzej Dobek},
doi = {10.1039/C7CP04061J},
year = {2017},
date = {2017-09-08},
journal = {Physical Chemistry Chemical Physics},
volume = {19},
number = {39},
pages = {26749-26757},
abstract = {Nonlinear THz pump–optical probe (THz–OKE) measurements in deionized, distilled and buffered (PBS) water are reported. A laser system that produces pulses at 800 nm, 30 fs FWHM, at a repetition rate of 1 kHz and an energy of 6 μJ per pulse, was a source of the probe optical beam and of the pump beam of THz 2 ps pulses. The electric field strength inducing birefringence in water samples was ETHz = 1.35 × 106 V m−1. These samples were chosen in order to study the effect of ionic concentration on water behavior in the ultrafast time scale. Differentiation between ultrafast effects resulting from internal H2O properties and those resulting from H2O–ion interactions was analyzed. These two effects may be connected to a difference in the fluctuations of the network of intermolecular hydrogen bonds of water molecules in the presence and absence of ions in solution. The results indicate that such fluctuations significantly alter water birefringence amplitude and its dynamics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Nonlinear THz pump–optical probe (THz–OKE) measurements in deionized, distilled and buffered (PBS) water are reported. A laser system that produces pulses at 800 nm, 30 fs FWHM, at a repetition rate of 1 kHz and an energy of 6 μJ per pulse, was a source of the probe optical beam and of the pump beam of THz 2 ps pulses. The electric field strength inducing birefringence in water samples was ETHz = 1.35 × 106 V m−1. These samples were chosen in order to study the effect of ionic concentration on water behavior in the ultrafast time scale. Differentiation between ultrafast effects resulting from internal H2O properties and those resulting from H2O–ion interactions was analyzed. These two effects may be connected to a difference in the fluctuations of the network of intermolecular hydrogen bonds of water molecules in the presence and absence of ions in solution. The results indicate that such fluctuations significantly alter water birefringence amplitude and its dynamics.
Pokrzywa, Małgorzata; Pawełek, Katarzyna; Kucia, Weronika; Sarbak, Szymon; Chorell, Erik; Almqvist, Fredrik; Wittung-Stafshede, Pernilla
Effects of small-molecule amyloid modulators on a Drosophila model of Parkinson’s disease Journal Article
In: PLOS ONE, vol. 12, no. 9, pp. 1-21, 2017.
Abstract | Links | BibTeX | Tagi:
@article{Pokrzywa2017,
title = {Effects of small-molecule amyloid modulators on a Drosophila model of Parkinson’s disease},
author = {Małgorzata Pokrzywa and Katarzyna Pawełek and Weronika Kucia and Szymon Sarbak and Erik Chorell and Fredrik Almqvist and Pernilla Wittung-Stafshede},
url = {https://doi.org/10.1371/journal.pone.0184117},
doi = {10.1371/journal.pone.0184117},
year = {2017},
date = {2017-01-01},
journal = {PLOS ONE},
volume = {12},
number = {9},
pages = {1-21},
publisher = {Public Library of Science},
abstract = {Alpha-synuclein (aS) amyloid formation is involved in Parkinson’s disease (PD); therefore, small molecules that target aS and affect its aggregation are of interest as future drug candidates. We recently reported modified ring-fused 2-pyridones that modulate aS amyloid formation in vitro. Here, we describe the effects of such molecules on behavioral parameters of a Drosophila model of PD (i.e., flies expressing human aS), using a new approach (implemented in a commercially available FlyTracker system) to quantify fly mobility. FlyTracker allows for automated analysis of walking and climbing locomotor behavior, as it collects large sequences of data over time in an unbiased manner. We found that the molecules per se have no toxic or kinetic effects on normal flies. Feeding aS-expressing flies with the amyloid-promoting molecule FN075, remarkably, resulted in increased fly mobility at early time points; however, this effect switched to reduced mobility at later time points, and flies had shorter life spans than controls. In contrast, an amyloid inhibitor increased both fly kinetics and life span. In agreement with increased aS amyloid formation, the FN075-fed flies had less soluble aS, and in vitro aS-FN075 interactions stimulated aS amyloid formation. In addition to a new quantitative approach to probe mobility (available in FlyTracker), our results imply that aS regulates brain activity such that initial removal (here, by FN075-triggered assembly of aS) allows for increased fly mobility.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Alpha-synuclein (aS) amyloid formation is involved in Parkinson’s disease (PD); therefore, small molecules that target aS and affect its aggregation are of interest as future drug candidates. We recently reported modified ring-fused 2-pyridones that modulate aS amyloid formation in vitro. Here, we describe the effects of such molecules on behavioral parameters of a Drosophila model of PD (i.e., flies expressing human aS), using a new approach (implemented in a commercially available FlyTracker system) to quantify fly mobility. FlyTracker allows for automated analysis of walking and climbing locomotor behavior, as it collects large sequences of data over time in an unbiased manner. We found that the molecules per se have no toxic or kinetic effects on normal flies. Feeding aS-expressing flies with the amyloid-promoting molecule FN075, remarkably, resulted in increased fly mobility at early time points; however, this effect switched to reduced mobility at later time points, and flies had shorter life spans than controls. In contrast, an amyloid inhibitor increased both fly kinetics and life span. In agreement with increased aS amyloid formation, the FN075-fed flies had less soluble aS, and in vitro aS-FN075 interactions stimulated aS amyloid formation. In addition to a new quantitative approach to probe mobility (available in FlyTracker), our results imply that aS regulates brain activity such that initial removal (here, by FN075-triggered assembly of aS) allows for increased fly mobility.
2016
Kucia, Weronika; Sharma, Gargi; Joseph, Cecil S; Sarbak, Szymon; Oliver, Cameron; Dobek, Andrzej; Giles, Robert H
Optical Kerr effect of tRNA solution induced by femtosecond laser pulses Journal Article
In: Chemical Physics Letters, vol. 662, pp. 132–136, 2016, ISSN: 00092614.
Abstract | Links | BibTeX | Tagi:
@article{Kucia2016,
title = {Optical Kerr effect of tRNA solution induced by femtosecond laser pulses},
author = {Weronika Kucia and Gargi Sharma and Cecil S Joseph and Szymon Sarbak and Cameron Oliver and Andrzej Dobek and Robert H Giles},
url = {https://www.sciencedirect.com/science/article/pii/S0009261416306996 http://linkinghub.elsevier.com/retrieve/pii/S0009261416306996},
doi = {10.1016/j.cplett.2016.09.027},
issn = {00092614},
year = {2016},
date = {2016-10-01},
journal = {Chemical Physics Letters},
volume = {662},
pages = {132--136},
publisher = {North-Holland},
abstract = {The optical Kerr effect (OKE) in a transfer ribonucleic acid (tRNA) solution induced by femtosecond pulses of linearly polarized pump light ($łambda$i=800nm) and sounded by probe light ($łambda$p=800nm) was studied. The measurements were performed to find nonlinear optical parameters describing a single molecule (molecular Kerr constant K, mean nonlinear third order optical polarizability cpi) and to compare them with our previous OKE results obtained in ns and ps time range. The OKE experiment has proven to be an efficient method to obtain the nonlinear parameters of single molecules in solution, which reflects dynamic structure changes.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The optical Kerr effect (OKE) in a transfer ribonucleic acid (tRNA) solution induced by femtosecond pulses of linearly polarized pump light ($łambda$i=800nm) and sounded by probe light ($łambda$p=800nm) was studied. The measurements were performed to find nonlinear optical parameters describing a single molecule (molecular Kerr constant K, mean nonlinear third order optical polarizability cpi) and to compare them with our previous OKE results obtained in ns and ps time range. The OKE experiment has proven to be an efficient method to obtain the nonlinear parameters of single molecules in solution, which reflects dynamic structure changes.