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Université de Fribourg

The reproducibility of SfM algorithms to produce detailed Digital Surface Models: the example of PhotoScan applied to a high-alpine rock glacier

Hendrickx, Hanne ; Vivero, Sebastián ; Cock, Laure De ; De Wit, Bart ; De Maeyer, Philippe ; Lambiel, Christophe ; Delaloye, Reynald ; Nyssen, Jan ; Frankl, Amaury

In: Remote Sensing Letters, 2019, vol. 10, no. 1, p. 11–20

In geomorphology, PhotoScan is a software that is used to produce Digital Surface Models (DSMs). It constructs 3D environments from 2D imagery (often taken by Unmanned Aerial Vehicles (UAV)) based on Structure-from-Motion (SfM) and Multi- View Stereo (MVS) principles. However, unpublished computer-vision algorithms used, contain random elements which can affect the accuracy of the outputs. For...

Università della Svizzera italiana

P2X7 receptor restrains pathogenic Tfh cell generation in systemic lupus erythematosus

Faliti, Caterina E. ; Gualtierotti, Roberta ; Rottoli, Elsa ; Gerosa, Maria ; Perruzza, Lisa ; Romagnani, Andrea ; Pellegrini, Giovanni ; De Ponte Conti, Benedetta ; Rossi, Riccardo L. ; Idzko, Marco ; Mazza, Emilia M.C. ; Bicciato, Silvio ; Traggiai, Elisabetta ; Meroni, Pier Luigi ; Grassi, Fabio

In: Journal of Experimental Medicine, 2019, vol. 216, no. 2, p. 317-336

Altered control of T follicular helper (Tfh) cells can lead to generation of autoantibodies and autoimmune manifestations. Signaling pathways that selectively limit pathogenic responses without affecting the protective function of Tfh cells are unknown. Here we show that the ATP-gated ionotropic P2X7 receptor restricts the expansion of aberrant Tfh cells and the generation of self-reactive...

Università della Svizzera italiana

Physiological protein blocks direct the Mre11–Rad50–Xrs2 and Sae2 nuclease complex to initiate DNA end resection

Reginato, Giordano ; Cannavo, Elda ; Cejka, Petr

In: Genes and Development, 2017, vol. 31, no. 23-24, p. 2325-2330

DNA double-strand break repair by homologous recombination is initiated by DNA end resection, which is commenced by the Mre11–Rad50–Xrs2 complex and Sae2 in yeast. Here we report that the nonhomologous end joining factor Ku limits the exonuclease activity of Mre11 and promotes its endonuclease to cleave 5'-terminated DNA strands at break sites. Following initial endonucleolytic cleavage...

Université de Fribourg

Nanoparticle administration method in cell culture alters particle-cell interaction

Moore, Thomas L. ; Urban, Dominic A. ; Rodriguez-Lorenzo, Laura ; Milosevic, Ana ; Crippa, Federica ; Spuch-Calvar, Miguel ; Balog, Sandor ; Rothen-Rutishauser, Barbara ; Lattuada, Marco ; Petri-Fink, Alke

In: Scientific Reports, 2019, vol. 9, no. 1, p. 900

As a highly interdisciplinary field, working with nanoparticles in a biomedical context requires a robust understanding of soft matter physics, colloidal behaviors, nano- characterization methods, biology, and bio-nano interactions. When reporting results, it can be easy to overlook simple, seemingly trivial experimental details. In this context, we set out to understand how in vitro...

Université de Fribourg

Nanoparticles and Taylor dispersion as a linear time-invariant system

Lemal, Philipp ; Petri-Fink, Alke ; Balog, Sandor

In: Analytical Chemistry, 2019, vol. 91, no. 2, p. 1217–1221

The physical principles underpinning Taylor dispersion offer a high dynamic range to characterize the hydrodynamic radius of particles. While Taylor dispersion grants the ability to measure radius within nearly 5 orders of magnitude, the detection of particles is never instantaneous. It requires a finite sample volume, a finite detector area, and a finite detection time for measuring...

Université de Fribourg

Time- and angle-resolved photoemission spectroscopy of solids in the extreme ultraviolet at 500 kHz repetition rate

Puppin, M. ; Deng, Y. ; Nicholson, C. W. ; Feldl, J. ; Schröter, N. B. M. ; Vita, H. ; Kirchmann, P. S. ; Monney, Claude ; Rettig, L. ; Wolf, M. ; Ernstorfer, R.

In: Review of Scientific Instruments, 2019, vol. 90, no. 2, p. 023104

Time- and angle-resolved photoemission spectroscopy (trARPES) employing a 500 kHz extreme-ultraviolet light source operating at 21.7 eV probe photon energy is reported. Based on a high-power ytterbium laser, optical parametric chirped pulse amplification, and ultraviolet-driven high-harmonic generation, the light source produces an isolated high-harmonic with 110 meV bandwidth and a flux of...

Université de Fribourg

Litter decomposition driven by soil fauna, plant diversity and soil management in urban gardens

Tresch, Simon ; Frey, David ; Le Bayon, Renée-Claire ; Zanettac, Andrea ; Rasche, Frank ; Fliessbach, Andreas ; Moretti, Marco

In: Science of The Total Environment, 2019, vol. 658, p. 1614–1629

In the face of growing urban densification, green spaces in cities, such as gardens, are increasingly important for biodiversity and ecosystem services. However, the influences of urban green space management on biodiversity and ecosystem functioning (BEF) relationships is poorly understood. We investigated the relationship between soil fauna and litter decomposition in 170 urban garden sites...

Université de Fribourg

Dopamine transporter (DAT) knockdown in the nucleus accumbens improves anxiety- and depression-related behaviors in adult mice

Bahi, Amine ; Dreyer, Jean-Luc

In: Behavioural Brain Research, 2019, vol. 359, p. 104–115

Many epidemiological and clinical studies have demonstrated a strong comorbidity between anxiety and depression, and a number of experimental studies indicates that the dopamine transporter (DAT) is involved in the pathophysiology of anxiety and depression. However, studies using laboratory animals have yielded inconclusive results. The aim of the present study was to examine the effects of...

Université de Fribourg

Vectorial import via a metastable disulfide-linked complex allows for a quality control step and import by the mitochondrial disulfide relay

Habich, Markus ; Salscheider, Silja Lucia ; Murschall, Lena Maria ; Hoehne, Michaela Nicole ; Fischer, Manuel ; Schorn, Fabian ; Petrungaro, Carmelina ; Ali, Muna ; J.Erdogan, Alican ; Abou-Eid, Shadi ; Kashkar, Hamid ; Dengjel, Joern ; Riemer, Jan

In: Cell Reports, 2019, vol. 26, no. 3, p. 759-774.e5

Disulfide formation in the mitochondrial intermembrane space (IMS) is an essential process. It is catalyzed by the disulfide relay machinery, which couples substrate import and oxidation. The machinery relies on the oxidoreductase and chaperone CHCHD4-Mia40. Here, we report on the driving force for IMS import and on a redox quality control mechanism. We demonstrate that unfolded reduced...