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Université de Fribourg

Probing intraband excitations in ${\mathrm{ZrTe}}_{5}$: A high-pressure infrared and transport study

Santos-Cottin, D. ; Padlewski, M. ; Martino, E. ; David, S. Ben ; Mardelé, F. Le ; Capitani, F. ; Borondics, F. ; Bachmann, M. D. ; Putzke, C. ; Moll, P. J. W. ; Zhong, R. D. ; Gu, G. D. ; Berger, H. ; Orlita, M. ; Homes, C. C. ; Rukelj, Z. ; Akrap, Ana

In: Physical Review B, 2020, vol. 101, no. 12, p. 125205

Zirconium pentatetelluride, ZrTe5, shows remarkable sensitivity to hydrostatic pressure. In this work we address the high-pressure transport and optical properties of this compound, on samples grown by flux and chemical vapor transport. The high-pressure resistivity is measured up to 2 GPa, and the infrared transmission up to 9 GPa. The dc conductivity anisotropy is determined using a...

Université de Fribourg

Magneto-optics of a Weyl semimetal beyond the conical band approximation: case study of tap

Polatkan, S. ; Goerbig, M. O. ; Wyzula, J. ; Kemmler, R. ; Maulana, L. Z. ; Piot, B. A. ; Crassee, I. ; Akrap, Ana ; Shekhar, C. ; Felser, C. ; Dressel, M. ; Pronin, A. V. ; Orlita, M.

In: Physical Review Letters, 2020, vol. 124, no. 17, p. 176402

Landau-level spectroscopy, the optical analysis of electrons in materials subject to a strong magnetic field, is a versatile probe of the electronic band structure and has been successfully used in the identification of novel states of matter such as Dirac electrons, topological materials or Weyl semimetals. The latter arise from a complex interplay between crystal symmetry, spin-orbit...

Université de Fribourg

Mahan excitons in room-temperature methylammonium lead bromide perovskites

Palmieri, Tania ; Baldini, Edoardo ; Steinhoff, Alexander ; Akrap, Ana ; Kollár, Márton ; Horváth, Endre ; Forró, László ; Jahnke, Frank ; Chergui, Majed

In: Nature Communications, 2020, vol. 11, no. 1, p. 850

In a seminal paper, Mahan predicted that excitonic bound states can still exist in a semiconductor at electron-hole densities above the insulator-to-metal Mott transition. However, no clear evidence for this exotic quasiparticle, dubbed Mahan exciton, exists to date at room temperature. In this work, we combine ultrafast broadband optical spectroscopy and advanced many-body calculations to...

Université de Fribourg

Magi1, a new potential tumor suppressor gene in estrogen receptor positive breast cancer

Alday-Parejo, Begoña ; Richard, François ; Wörthmüller, Janine ; Rau, Tilman ; Galván, José A. ; Desmedt, Christine ; Santamaria-Martinez, Albert ; Rüegg, Curzio

In: Cancers, 2020, vol. 12, no. 1, p. 223

Membrane-associated guanylate kinase (MAGUK) with inverted domain structure-1 (MAGI1) is an intracellular adaptor protein that stabilizes epithelial junctions consistent with a tumor suppressive function in several cancers of epithelial origin. Here we report, based on experimental results and human breast cancer (BC) patients’ gene expression data, that MAGI1 is highly expressed and acts...

Université de Fribourg

Rapid polymyxin/pseudomonas NP test for rapid detection of polymyxin susceptibility/resistance in Pseudomonas aeruginosa

Sadek, Mustafa ; Tinguely, Camille ; Poirel, Laurent ; Nordmann, Patrice

In: European Journal of Clinical Microbiology & Infectious Diseases, 2020, p. -

Polymyxins are becoming an added value for treating infections due to multidrug-resistant Pseudomonas aeruginosa. Therefore, the Rapid Polymyxin/Pseudomonas NP test was developed for the identification of polymyxin resistance in P. aeruginosa isolates. This test detects the bacterial growth in a medium containing a defined concentration of colistin. Formation of basic metabolites is visually...

Université de Fribourg

Occurrence of NDM-1-producing Morganella morganii and Proteus mirabilis in a single patient in Portugal: probable in vivo transfer by conjugation

Aires-de-Sousa, Marta ; Ortiz de la Rosa, José Manuel ; Goncalves, Maria Luísa ; Costa, Augusto ; Nordmann, Patrice ; Poirel, Laurent

In: Journal of Antimicrobial Chemotherapy, 2020, vol. 75, no. 4, p. 903–906

To decipher the genetics of acquisition of carbapenemase-encoding genes identified in two carbapenem-resistant Enterobacteriaceae recovered from a single patient in Portugal.Methods: Carbapenemase genes were searched by PCR assays and mating-out assays were performed to further characterize the plasmid support of the carbapenemase genes. Genetic characterization of the plasmid supports was...

Université de Fribourg

Optimal detection of extended-spectrum β-lactamase producers, carbapenemase producers, polymyxin-resistant Enterobacterales, and vancomycin-resistant enterococci from stools

Sadek, Mustafa ; Poirel, Laurent ; Nordmann, Patrice

In: Diagnostic Microbiology and Infectious Disease, 2020, vol. 96, no. 1, p. 114919

This study compared the impact of different approaches, namely, nonenrichment, nonselective enrichment, and selective (antibiotic-containing) enrichment steps, for detecting extended-spectrum β-lactamase producing Enterobacterales (ESBL-E), carbapenemase-producing Enterobacterales (CPE), polymyxin-resistant Enterobacterales (PMR-E), and vancomycin- resistant enterococci (VRE) from spiked...

Université de Fribourg

ISEcp1 mediated transposition leads to fosfomycin and broad-spectrum cephalosporin resistance in Klebsiella pneumoniae

Kieffer, Nicolas ; Poirel, Laurent ; Mueller, Linda ; Mancini, Stefano ; Nordmann, Patrice

In: Antimicrobial Agents and Chemotherapy, 2020, vol. 64, no. 5, p. -

A fosfomycin-resistant and carbapenemase (OXA-48)-producing Klebsiella pneumoniae isolate was recovered, and whole-genome sequencing revealed ISEcp1-blaCTX-M-14b tandemly inserted upstream of the chromosomally encoded lysR-fosA locus. Quantitative evaluation of the expression of lysR and fosA genes showed that this insertion brought a strong hybrid promoter leading to overexpression of the...