École Polytechnique Fédérale de Lausanne
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Targeted barcoding of variable antibody domains and individual transcriptomes of the human B-cell repertoire using Link-Seq
No full textHere, we present Link-Seq, a highly efficient droplet microfluidic method for combined sequencing of antibody-encoding genes and the transcriptome of individual B cells at large scale. The method is based on 3 ' barcoding of the transcriptome and subsequent single-molecule PCR in droplets, which freely shift the barcode along specific gene regions, such as the antibody heavy- and light-chain genes. Using the immune repertoire of COVID-19 patients and healthy donors as a model system, we obtain up to 91.7% correctly paired immunoglobulin heavy and light chains. Furthermore, we map the V(D)J usage and obtain sensitivities comparable with the current gold-standard 10x Genomics commercial systems while offering full flexibility in experimental setup and significant cost savings. A further unique feature of Link-Seq is the possibility of barcoding multiple target genes in a site-specific manner. Based on the open character of the platform and its conceptual advantages, we expect Link-Seq to become a versatile tool for single-cell analysis, especially for applications requiring additional processing steps that cannot be implemented on commercially available platforms.LBM
When urgency knocks at the door Converting commercial space into housing & a production workshop in Geneva
No full textThe housing crisis in Geneva has been an issue since the beginning of the 20th century, and one that is becoming increasingly urgent today. The research I carried out during the statement, First Struggle Then Housing, led me to analyze the Ciguë report published in 2021, highlighting the fact that almost 350,000 m2 of commercial space are empty in the canton of Geneva. Wouldn’t it be urgent to reinvest these vacant spaces and rethink our models of housing accessibility, as well as our ways of conceiving living together on a building and neighborhood scale? This project is inspired by Nina Rappaport’s reflections in Hybrid Factory, Hybrid City, underlining the importance of urban regeneration for a new vision where housing coexists with industry, questioning the current urban model. Cooperative housing is a popular answer today, and while it offers many advantages, it remains very limited in terms of access, both financially – the price per square meter to invest is now mainly affordable for the middle class – and in terms of physical access to the building for the rest of the neighborhood. This project proposes to rethink living together both inside and outside the building, in order to build a solid, supportive social fabric with minimal intervention on the structure, while allowing for participative construction. In addition to offering communal spaces for residents, the building also features a first floor and roof open to the neighborhood’s remnants. Ideally located close to the station and the city center, it also incorporates workshops to make it a place for professional exchange.ALICEENAC-SARCote: 2024.089MEM.1/1Groupe de suivi: Dietz, Dieter (dir. pédagogique) ; Aureli, Pier Vittorio (prof.) ; Devalle, Jolanda (maître EPFL) ; Wellinger, Jeanne (expert)Professeur responsable de l'Enoncé: Aureli, Pier Vittorio (ENAC IA TPOD)Enoncé théorique de master: First Struggle. Then Housing. A Critical History of Social Housing in Geneva (1850 - 2023
Towards Self-regeneration: Exploring the Limits of Protein Synthesis in the Protein Synthesis Using Recombinant Elements (PURE) Cell-free Transcription-Translation System
No full textSelf-regeneration is a key function of living systems that needs to be recapitulated in vitro to create a living synthetic cell. A major limiting factor for protein self-regeneration in the PURE cell-free transcription-translation system is its high protein concentration, which far exceeds the system's protein synthesis rate. Here, we were able to drastically reduce the nonribosomal PURE protein concentration up to 97.3% while increasing protein synthesis efficiency. Although crowding agents were not effective in the original PURE formulation, we found that in highly dilute PURE formulations, addition of 6% dextran considerably increased protein synthesis rate and total protein yield. These new PURE formulations will be useful for many cell-free synthetic biology applications, and we estimate that PURE can now support the complete self-regeneration of all 36 nonribosomal proteins, which is a critical step toward the development of a universal biochemical constructor and living synthetic cell.LBN
Amplitude analysis of <i>B</i><SUP>+</SUP> → ψ(2<i>S</i>)<i>K</i><SUP>+</SUP> π<SUP>+</SUP> π<SUP>-</SUP> decays
No full textThe first full amplitude analysis of B+ -> psi(2S)K+pi(+)pi(-) decays is performed using proton-proton collision data corresponding to an integrated luminosity of 9 fb(-1) recorded with the LHCb detector. The rich K+pi(+)pi(-) spectrum is studied and the branching fractions of the resonant substructure associated with the prominent K-1(1270)(+) contribution are measured. The data cannot be described by conventional strange and charmonium resonances only. An amplitude model with 53 components is developed comprising 11 hidden-charm exotic hadrons. New production mechanisms for charged charmonium-like states are observed. Significant resonant activity with spin-parity J(P) = 1(+) in the psi(2S)pi(+) system is confirmed and a multi-pole structure is demonstrated. The spectral decomposition of the psi(2S)pi(+)pi(-) invariant-mass structure, dominated by X-0 -> psi(2S)rho(770)(0) decays, broadly resembles the J/psi phi spectrum observed in B+ -> J/psi phi K+ decays. Exotic psi(2S)K+pi(-) resonances are observed for the first time.LPHE-OSPH-SBLPHE-RMLPHE-L
A deep learning pipeline for three-dimensional brain-wide mapping of local neuronal ensembles in teravoxel light-sheet microscopy
No full textTeravoxel-scale, cellular-resolution images of cleared rodent brains acquired with light-sheet fluorescence microscopy have transformed the way we study the brain. Realizing the potential of this technology requires computational pipelines that generalize across experimental protocols and map neuronal activity at the laminar and subpopulation-specific levels, beyond atlas-defined regions. Here, we present artficial intelligence-based cartography of ensembles (ACE), an end-to-end pipeline that employs three-dimensional deep learning segmentation models and advanced cluster-wise statistical algorithms, to enable unbiased mapping of local neuronal activity and connectivity. Validation against state-of-the-art segmentation and detection methods on unseen datasets demonstrated ACE's high generalizability and performance. Applying ACE in two distinct neurobiological contexts, we discovered subregional effects missed by existing atlas-based analyses and showcase ACE's ability to reveal localized or laminar neuronal activity brain-wide. Our open-source pipeline enables whole-brain mapping of neuronal ensembles at a high level of precision across a wide range of neuroscientific applications.UPCOURTIN
Nanocomposites Based on Thermoplastic Acrylic Resin with the Addition of Chemically Modified Multi-Walled Carbon Nanotubes
No full textThe main goal of this work was an improvement in the mechanical and electrical properties of acrylic resin-based nanocomposites filled with chemically modified carbon nanotubes. For this purpose, the surface functionalization of multi-walled carbon nanotubes (MWCNTs) was carried out by means of aryl groups grafting via the diazotization reaction with selected aniline derivatives, and then nanocomposites based on ELIUM® resin were fabricated. FT-IR analysis confirmed the effectiveness of the carried-out chemical surface modification of MWCNTs as new bands on FT-IR spectra appeared in the measurements. TEM observations showed that carbon nanotube fragmentation did not occur during the modifications. According to the results from Raman spectroscopy, the least defective carbon nanotube structure was obtained for aniline modification. Transmission light microscopy analysis showed that the neat MWCNTs agglomerate strongly, while the proposed modifications improved their dispersion significantly. Viscosity tests confirmed, that as the nanofiller concentration increases, the viscosity of the mixture increases. The mixture with the highest dispersion of nanoparticles exhibited the most viscous behaviour. Finally, an enhancement in impact resistance and electrical conductivity was obtained for nanocomposites containing modified MWCNTs.EPF
Search for the Bs0→ μ<sup>+</sup>μ<sup>−</sup>γ decay
Get PDFA search for the fully reconstructed Bs0→ μ+μ−γ decay is performed at the LHCb experiment using proton-proton collisions at s = 13 TeV corresponding to an integrated luminosity of 5.4 fb−1. No significant signal is found and upper limits on the branching fraction in intervals of the dimuon mass are set (Formula presented.) at 95% confidence level. Additionally, upper limits are set on the branching fraction in the [2mμ, 1.70] GeV/c2 dimuon mass region excluding the contribution from the intermediate ϕ(1020) meson, and in the region combining all dimuon-mass intervals.LPHE-OSPH-SBLPHE-RMLPHE-L
Coupling Free Electrons and Cavity Photons in a Transmission Electron Microscope
No full textWe couple free electrons to the optical modes of a photonic microring resonator. Inelastic electron scattering leads to the generation of cavity photons, correlated to the electrons in time and energy loss.LPQM1LPQM
The Role of Oxygen Exposure on the Performance of All-Vapor-Processed Perovskite Solar Cells With CuPC Hole Transport Layers
No full textMethylammonium lead iodide (MAPbI(3)) perovskite solar cells were made using an all-vapor process, including two-step close space vapor transport-processed MAPbI(3) absorber and evaporated copper phthalocyanine (CuPC) hole transport layer (HTL). N-i-p solar cells fabricated entirely in a nitrogen glovebox had poor performance due to s-shaped J-V curves and fill factors (FF) 45%. Solar cells exposed to dry air in a desiccator for seven days, or to O-2 flowed into the evaporator during CuPC deposition, had significantly improved performance with reduced or eliminated s-shaped behavior and improved FF up to 72%. Co-planar conductivity measurements show that exposure to dry air, deposition with oxygen, and MoOx capping layers all increase the conductivity of the CuPC HTL. Drift-diffusion simulations show that increasing hole concentration consistent with oxygen doping effects can explain the J-V behavior of the solar cell. Solar cells using spiro-OMeTAD HTLs achieved similar Power Conversion Efficiency but higher V-oc up to 1.01 V. Drift-diffusion simulations show that the V-oc difference can be explained by differences in doping density and valence band position between spiro and CuPC.PV-LA