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, Rosa Mosteo, David Muzard, Cristina del Socorro Lonfat, Stefanos Giannakis, 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

Juan Kiwi, César Pulgarin, 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, Fernando Cortes Salazar, Liang Qiao, Andreas Stephan Lesch, Alexandra Bondarenko, Tzu-En Lin

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

Degradation rates of benzotriazoles and benzothiazoles under UV-C irradiation and the advanced oxidation process UV/H2O2

Silvio Canonica, Urs von Gunten

Benzotriazoles (BTs) and benzothiazoles (BTHs) are extensively used chemicals found in a wide range of household and industrial products. They are chemically stable and are therefore ubiquitous in the aquatic environment. The present study focuses on the p ...

Elsevier2015

A Subpopulation of Smooth Muscle Cells, Derived from Melanocyte-Competent Precursors, Prevents Patent Ductus Arteriosus

Friedrich Beermann

Background: Patent ductus arteriosus is a life-threatening condition frequent in premature newborns but also present in some term infants. Current mouse models of this malformation generally lead to perinatal death, not reproducing the full phenotypic spec ...

Public Library of Science2013

Light-responsive polymer nanoreactors: a source of reactive oxygen species on demand

Andrzej Sienkiewicz

Various domains present the challenges of responding to stimuli in a specific manner, with the desired sensitivity or functionality, and only when required. Stimuli-responsive systems that are appropriately designed can effectively meet these challenges. H ...

Royal Soc Chemistry2013

Coat color dilution in mice because of inactivation of the melanoma antigen MART-1

Friedrich Beermann, Iraz Toprak Aydin

Melanoma antigen recognized by T cells 1 (MART-1) is a melanoma-specific antigen, which has been thoroughly studied in the context of immunotherapy against malignant melanoma and which is found only in the pigment cell lineage. However, its exact function ...

2012

A MART-1::Cre transgenic line induces recombination in melanocytes and RPE

Friedrich Beermann, Iraz Toprak Aydin

The number of transgenic mouse lines expressing Cre in either type of pigment cells (melanocytes and retinal pigment epithelium, RPE) is limited, and the available lines do not always offer sufficient specificity. In this study, we addressed this issue and ...

2011

Analysis of the Pigment Cell Specific Gene MART-1/Melan-A/mlana : Expressional Regulation and Function

Iraz Toprak Aydin

Pigmentation is a complex process that provides many diverse benefits for the organism. Pigment production takes place in the pigment cell lineage in dedicated organelles called melanosomes. Several proteins are specifically recruited to melanosomes for th ...

EPFL2010

Differential roles of the pRb and Arf/p53 pathways in murine naevus and melanoma genesis

Friedrich Beermann

Summary We report on a systematic analysis of genotype-specific melanocyte UVR responses in transgenic mouse melanoma models along with tumour penetrance and comparative histopathology. pRb or p53 pathway mutations cooperated with Nras(Q61K) to transform m ...

2010

Key roles for transforming growth factor beta in melanocyte stem cell maintenance

Friedrich Beermann

Melanocyte stem cells in the bulge area of hair follicles are responsible for hair pigmentation, and defects in them cause hair graying. Here we describe the process of melanocyte stem cell entry into the quiescent state and show that niche-derived transfo ...

2010

Identification of epidermal pdx1 expression discloses different roles of notch1 and notch2 in murine kras-induced skin carcinogenesis in vivo

Freddy Radtke

BACKGROUND: The Ras and Notch signaling pathways are frequently activated during development to control many diverse cellular processes and are often dysregulated during tumorigenesis. To study the role of Notch and oncogenic Kras signaling in a progenitor ...

Public Library of Science2010

Murine Neonatal Melanocytes Exhibit a Heightened Proliferative Response to Ultraviolet Radiation and Migrate to the Epidermal Basal Layer

Friedrich Beermann

Melanocytes respond to UVR not only by producing melanin, but also by proliferating. This is essentially a protective response. We have studied the melanocyte proliferative response after a single UVR exposure to neonatal mice. At 3 days post-UVR in wild-t ...

2009