Daniel S. Ory

Électricité de France (France)

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Jean‐François Guillemoles

Centre National de la Recherche Scientifique

Laurent Lombez

Institut Photovoltaïque d’Île-de-France

Stéfania Cacovich

Institut Photovoltaïque d’Île-de-France

Adrien Bercegol

Électricité de France (France)

Jean‐Baptiste Puel

Institut de France

Jean Rousset

Électricité de France (France)

Jean E. Schaffer

Harvard University

Guillaume Vidon

Chimie ParisTech

Forbes D. Porter

Eunice Kennedy Shriver National Institute of Child Health and Human Development

Daniel Suchet

Chimie ParisTech

Cooperative Institutions

Washington University in St. Louis

101

Centre National de la Recherche Scientifique

National Institutes of Health

Institut Photovoltaïque d’Île-de-France

Institut de France

Institut national de l’information géographique et forestière

Harvard University

Chimie ParisTech

Électricité de France (France)

Institut Pprime

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Fourier Transform Infrared Microscopy Enables Guidance of Automated Mass Spectrometry Imaging to Predefined Tissue Morphologies

Scientific Reports (2018)

Jan-Hinrich Rabe Denis Abu Sammour Sandra Schulz Bogdan Munteanu Martina Ott

Abstract Multimodal imaging combines complementary platforms for spatially resolved tissue analysis that are poised for application in life science and personalized medicine. Unlike established clinical in vivo multimodality imaging, automated workflows for in-depth multimodal molecular ex vivo tissue analysis that combine the speed and ease of spectroscopic imaging with molecular details provided by mass spectrometry imaging (MSI) are lagging behind. Here, we present an integrated approach that utilizes non-destructive Fourier transform infrared (FTIR) microscopy and matrix assisted laser desorption/ionization (MALDI) MSI for analysing single-slide tissue specimen. We show that FTIR microscopy can automatically guide high-resolution MSI data acquisition and interpretation without requiring prior histopathological tissue annotation, thus circumventing potential human-annotation-bias while achieving >90% reductions of data load and acquisition time. We apply FTIR imaging as an upstream modality to improve accuracy of tissue-morphology detection and to retrieve diagnostic molecular signatures in an automated, unbiased and spatially aware manner. We show the general applicability of multimodal FTIR-guided MALDI-MSI by demonstrating precise tumor localization in mouse brain bearing glioma xenografts and in human primary gastrointestinal stromal tumors. Finally, the presented multimodal tissue analysis method allows for morphology-sensitive lipid signature retrieval from brains of mice suffering from lipidosis caused by Niemann-Pick type C disease.

Mass spectrometry imaging

MALDI imaging

Infrared microscopy

Chemical Imaging

Molecular Imaging

Modality (human–computer interaction)

10.1038/s41598-017-18477-6

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Citations (49)

Analytical Characterization of Methyl-β-Cyclodextrin for Pharmacological Activity to Reduce Lysosomal Cholesterol Accumulation in Niemann-Pick Disease Type C1 Cells

Assay and Drug Development Technologies (2017)

Rong Li Jon Hao Hideji Fujiwara Miao Xu Shu Yang

Methyl-β-cyclodextrin (MβCD) reduces lysosomal cholesterol accumulation in Niemann-Pick disease type C1 (NPC1) patient fibroblasts. However, the pharmacological activity of MβCD reported by different laboratories varies. To determine the potential causes of this variation, we analyzed the mass spectrum characteristics, pharmacological activity of three preparations of MβCDs, and the protein expression profiles of NPC1 patient fibroblasts after treatment with different sources of MβCDs. Our data revealed varied mass spectrum profiles and pharmacological activities on the reduction of lysosomal cholesterol accumulation in NPC1 fibroblasts for these three preparations of MβCDs obtained from different batches and different sources. Furthermore, a proteomic analysis showed the differences of these three MβCD preparations on amelioration of dysregulated protein expression levels in NPC1 cells. The results demonstrate the importance of prescreening of different cyclodextrin preparations before use as a therapeutic agent. A combination of mass spectrum analysis, measurement of pharmacological activity, and proteomic profiling provides an effective analytical procedure for characterization of cyclodextrins for therapeutic applications.

NPC1

Broad spectrum

Beta-Cyclodextrins

10.1089/adt.2017.774

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Citations (19)

Hyperspectral Imaging of Photovoltaic Conversion

MRS Proceedings (2014)

Jean‐François Guillemoles Amaury Delamarre Gilbert El-Hajje Pierre Râle Jean Rodière

10.1557/opl.2014.700

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Citations (1)

Micrometric mapping of absolute trapping defects density using quantitative luminescence imaging

Gilbert El-Hajje Daniel S. Ory Jean‐François Guillemoles Laurent Lombez

In the present study, we develop a contactless optical characterization tool that quantifies and maps the trapping defects density within a thin film photovoltaic device. This is achieved by probing time-resolved photoluminescence and numerically reconstructing the experimental decays under several excitation conditions. The values of defects density in different Cu(In,Ga)Se ₂ solar cells were extracted and linked to photovoltaic performances such as the open-circuit voltage. In the second part of the work, the authors established a micrometric map of the trapping defects density. This revealed areas within the thin film CIGS solar cell with low photovoltaic performance and high trapping defects density. The final part of the work was dedicated to finding the origin of the spatial fluctuations of the thin film transport properties. To do so, we started by establishing a micrometric map of the absolute quasi-Fermi levels splitting within the same CIGS solar cell, using the hyperspectral imager. A correlation is obtained between the map of quasi-Fermi levels splitting of and the map of the trapping defects density. The latter is found to be the origin of the frequently observed spatial fluctuations of thin film materials properties.

10.1109/pvsc.2016.7749794

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“Mapping absorption coefficient of photovoltaic absorbers through photoluminescence imaging”

HAL (Le Centre pour la Communication Scientifique Directe) (2022)

Marie Legrand Baptiste Bérenguier Guillaume Vidon Daniel S. Ory Jean‐François Guillemoles

10.1117/12.2624478

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Degradation and Self‐Healing of FAPbBr₃ Perovskite under Soft‐X‐Ray Irradiation

Small Methods (2023)

Valeria Milotti Stéfania Cacovich Davide Raffaele Ceratti Daniel S. Ory Jessica Barichello

Abstract The extensive use of perovskites as light absorbers calls for a deeper understanding of the interaction of these materials with light. Here, the evolution of the chemical and optoelectronic properties of formamidinium lead tri‐bromide (FAPbBr 3 ) films is tracked under the soft X‐ray beam of a high‐brilliance synchrotron source by photoemission spectroscopy and micro‐photoluminescence. Two contrasting processes are at play during the irradiation. The degradation of the material manifests with the formation of Pb 0 metallic clusters, loss of gaseous Br 2 , decrease and shift of the photoluminescence emission. The recovery of the photoluminescence signal for prolonged beam exposure times is ascribed to self‐healing of FAPbBr 3 , thanks to the re‐oxidation of Pb 0 and migration of FA + and Br − ions. This scenario is validated on FAPbBr 3 films treated by Ar + ion sputtering. The degradation/self‐healing effect, which is previously reported for irradiation up to the ultraviolet regime, has the potential of extending the lifetime of X‐ray detectors based on perovskites.

Formamidinium

Degradation

10.1002/smtd.202300222

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Citations (17)

Investigation of the spatial distribution of hot carriers in quantum-well structures via hyperspectral luminescence imaging

Journal of Applied Physics (2020)

Hamidreza Esmaielpour Laurent Lombez Maxime Giteau Amaury Delamarre Daniel S. Ory

Observation of robust hot carrier effects in quantum-well structures has prompted hopes to increase the efficiency of solar cells beyond the Shockley–Queisser limit (33% for single junction solar cells at AM1.5G). One of the main studies in hot carrier effects is the determination of carrier temperature, which provides information on the thermalization mechanisms of hot carriers in semiconductor materials. Here, we investigate the spatial distribution of photo-generated hot carriers in a InGaAs multi-quantum-well structure via hyperspectral luminescence imaging. We discuss proper methods of extracting the temperature of carriers from a photoluminescence spectrum. Robust hot carrier effects are observed at the center of the laser spot at various lattice temperatures. In addition, it is seen that the local carrier temperature scales linearly with the local laser intensity as long as the illumination exceeds a threshold power; the carrier temperature at regions with local intensities below the threshold drops to the lattice temperature, i.e., experiences no hot carrier effects. Moreover, at large distances from the concentrated light, where the level of illumination is negligible, evidence of carrier radiative recombination is observed, which is attributed to carrier diffusion in the planar structure. The results of this study can be applied to investigate the influence of carrier diffusion and thermoelectric effects on the thermalization of hot carriers.

Carrier lifetime

Quantum Efficiency

Thermalisation

Charge carrier

10.1063/5.0022277

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Citations (16)

The Sterol-sensing Domain of the Niemann-Pick C1 (NPC1) Protein Regulates Trafficking of Low Density Lipoprotein Cholesterol

Journal of Biological Chemistry (2005)

Elizabeth E. Millard Sarah E. Gale Nicole Dudley Jessie Zhang Jean E. Schaffer

The Niemann-Pick C1 (NPC1) protein is a key participant in intracellular sterol trafficking and regulation of cholesterol homeostasis. NPC1 contains a pentahelical region that is evolutionarily related to sterol-sensing domains found in other polytopic proteins involved in sterol interactions or sterol metabolism, including sterol regulatory element-binding protein cleavage-activating protein and hydroxymethylglutaryl-CoA reductase. To gain insight into the role of the sterol-sensing domain of NPC1, we examined the effect of point mutations in the NPC1 sterol-sensing domain on the trafficking of low density lipoprotein-derived cholesterol and sphingolipids. We show that an NPC1 P692S loss of function mutation results in decreased cholesterol delivery to the plasma membrane and endoplasmic reticulum. By contrast, NPC1 proteins carrying a L657F or D787N point mutation, which correspond to the activating SCAP L315F and D443N mutations, respectively, exhibit a gain of function phenotype. Specifically, cell lines expressing the NPC1 L657F or D787N mutations show a nearly 2-fold increase in the rates of low density lipoprotein cholesterol trafficking to the plasma membrane and to the endoplasmic reticulum, and more rapid suppression of sterol regulatory element-binding protein-dependent gene expression. Trafficking of sphingolipids is intact in the D787N and L657F cell lines. Our finding that D787N and L657F are activating NPC1 mutations provide evidence for a conserved mechanism for the sterol-sensing domain among cholesterol homeostatic proteins.

NPC1

Sphingolipid

Sterol O-acyltransferase

10.1074/jbc.m414024200

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Citations (113)

Regulation of fibroblast mitochondrial 27-hydroxycholesterol production by active plasma membrane cholesterol

Journal of Lipid Research (2009)

Yvonne Lange Theodore L. Steck Jin Ye M. Hunter Lanier Vasumathi Molugu

Side chain oxysterols are cholesterol derivatives thought to signal the abundance of cell cholesterol to homeostatic effector proteins. Here, we investigated how plasma membrane (PM) cholesterol might regulate 27-hydroxycholesterol (HC) biosynthesis in cultured fibroblasts. We showed that PM cholesterol was a major substrate for 27-HC production. Biosynthesis commenced within minutes of loading depleted cells with cholesterol, concurrent with the rapid inactivation of hydroxy-3-methylglutaryl CoA reductase (HMGR). 27-HC production rose approximately 30-fold in normal and Niemann-Pick C1 fibroblasts when PM cholesterol was increased by approximately 60%. 27-HC production was also stimulated by 1-octanol, which displaces PM cholesterol from its phospholipid complexes and thereby increases its activity (escape tendency) and elevates its intracellular abundance. Conversely, lysophosphatidylserine and U18666A inhibited 27-HC biosynthesis and the inactivation of HMGR, presumably by reducing the activity of PM cholesterol and, therefore, its circulation to mitochondria. We conclude that, in this in vitro system, excess (active) PM cholesterol rapidly reaches mitochondria where, as the rate-limiting substrate, it stimulates 27-HC biosynthesis. The oxysterol product then promotes the rapid degradation of HMGR, along with other homeostatic effects. The regulation of 27-HC production by the active excess of PM cholesterol can thus provide a feedback mechanism in the homeostasis of PM cholesterol.

10.1194/jlr.m900116-jlr200

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Citations (47)

Oxysterols as non-genomic regulators of cholesterol homeostasis

Trends in Endocrinology and Metabolism (2012)

Agata A. Bielska Paul H. Schlesinger Douglas F. Covey Daniel S. Ory

Oxysterol

Homeostasis

Liver X receptor

10.1016/j.tem.2011.12.002

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Citations (52)