Publications associées à Regulation of DHICA-mediated antioxidation by dopachrome tautomerase: Implication for skin photoprotection against UVA radiation

Measuring the electron energy distribution in tokamak plasmas from polarized electron cyclotron radiation

In this doctoral thesis, a promising technique has been used for the measurement of non-thermal electrons in TCV. The technique employs a Vertical viewing ECE to more easily discriminate the radiation according to the energy of the electrons. Successful ...

EPFL2023

Identifying the mediators of intracellular E. coli inactivation under UVA light: The (photo) Fenton process and singlet oxygen

César Pulgarin, Stefanos Giannakis

Solar disinfection (SODIS) was probed for its underlying mechanism. When Escherichia coli was exposed to UVA irradiation, the dominant solar fraction acting in SODIS process, cells exhibited a shoulder before death ensued. This profile resembles cell killi ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Employing bacterial mutations for the elucidation of photo-Fenton disinfection: Focus on the intracellular and extracellular inactivation mechanisms induced by UVA and H2O2

César Pulgarin, Stefanos Giannakis, Ling Feng, Da Wang

The bacterial inactivation mechanisms by solar light and the photo-Fenton process is still a matter of debate. In this study, we bring evidence towards the elucidation of the mechanisms that govern photo-Fenton disinfection at near-neutral pH. With the use ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Visible light plays a significant role during bacterial inactivation by the photo-fenton process, even at sub-critical light intensities

César Pulgarin, Cristina del Socorro Lonfat, Stefanos Giannakis, Rosa Mosteo, David Muzard, Angelica Varon Lopez

The aim of this research is to clarify the contribution of sunlight wavelengths, irradiance and Fe2+/H2O2 during bacterial disinfection by the photo-Fenton process in clear surface waters. We considered different solar spectrum distributions (visible, UVA- ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Origin of High-Frequency Radiation During Laboratory Earthquakes

François Xavier Thibault Passelègue

We monitor dynamic rupture propagation during laboratory stick-slip experiments performed on saw-cut Westerly granite under upper crustal conditions (10-90 MPa). Spectral analysis of high-frequency acoustic waveforms provided evidence that energy radiation ...

AMER GEOPHYSICAL UNION2019

The melanization reaction in Drosophila: More than black or white

Jan Paul Dudzic

The melanization reaction is a rapid and important immune mechanism in arthropods. It results in the production of melanin at the site of injury and around invading microbes. The enzymes responsible for melanogenesis are phenoloxidases (PO), which catalyze ...

EPFL2018

Optical Thickness Measurements of Vacuum Ultraviolet Radiation in the X2 Expansion Tube

Umar Sheikh

Experiments were conducted in the X2 expansion tube to measure vacuum ultraviolet radiation from shock layers representative of reentry conditions at flight equivalent velocities of 10.0 and 12.2 km/s. Cylindrical models of varying lengths were used to mak ...

2016

Accelerated methylene blue (MB) degradation by Fenton reagent exposed to UV or VUV/UV light in an innovative micro photo-reactor

César Pulgarin, Juan Kiwi, Mengkai Li

This study presents the accelerated discoloration/degradation of methylene blue (MB) in solution by Fenton reagent under exposure to ultraviolet (UV) or Vacuum-UV/UV (VUV/UV) light in an innovative micro photo-reactor. The MB degradation was kinetically fa ...

Elsevier2016

Multiple scanning electrochemical microscopy mapping of tyrosinase in micro-contact printed fruit samples on polyvinylidene fluoride membrane

Hubert Girault, Andreas Stephan Lesch, Liang Qiao, Fernando Cortes Salazar, Tzu-En Lin, Alexandra Bondarenko

Herein, we introduce three orthogonal and compatible methods for detecting tyrosinase, a key factor in fruit browning and skin disorders, with high spatial resolution by means of scanning electrochemical microscopy (SECM). All methods are performed subsequ ...

Elsevier2015

Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

Andrzej Sienkiewicz, Fanny Caputo

Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic ...

Royal Soc Chemistry2015