546 results on '"Pere Roca"'
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2. Historical Development and Seismic Performance of Unreinforced Masonry Buildings with Vertical Extensions in the City Centre of Barcelona
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Cossima Cornado, Sara Dimovska, Savvas Saloustros, Francesca Marafini, Pere Roca, Universitat Politècnica de Catalunya. Doctorat en Enginyeria de la Construcció, Universitat Politècnica de Catalunya. Departament de Tecnologia de l'Arquitectura, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya. REARQ - Rehabilitació i Restauració Arquitectònica, and Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials
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Seismic analysis ,Visual Arts and Performing Arts ,Vertical irregularity ,Historical structures ,Enginyeria civil::Materials i estructures [Àrees temàtiques de la UPC] ,historical structures ,Vertical extensions ,Conservation ,vertical irregularity ,seismic analysis ,unreinforced masonry buildings ,Finite element modelling ,pushover analysis ,Unreinforced masonry buildings ,Estructures de murs ,Architecture ,vertical extensions ,Masonry ,Pushover analysis ,finite element modelling ,damage - Abstract
This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of Architectural Heritage on 2022, available online at: http://www.tandfonline.com/10.1080/15583058.2022.2096513 This paper presents the historical development of the vertical extensions of unreinforced masonry buildings in the Eixample district of Barcelona and their impact on the seismic behaviour. Existing masonry buildings of Eixample present significant seismic risk because, despite the low to moderate seismic hazard of Barcelona, they show a marked vulnerability given their average height of six storeys and the substantial slenderness of the walls. Between the end of the 19th century and the beginning of the 20th century, the vertical extensions, known as remuntes in Catalan, were a common solution to the increasing demographic demand of the city. In their majority, these vertical extensions add a structural irregularity that represents a potential vulnerability factor not yet investigated. The present study focuses on Eixample’s remuntes, including their historical development, the description of their structural features, and the identification of their most representative configurations in the existing building stock. A seismic analysis based on the Finite Element Method is presented on a reference model without extensions and three others with the most recurrent configurations of remuntes. The seismic response is investigated through pushover analysis. The results provide a better understanding of the negative impact of the vertical extensions on the seismic performance. This work was supported by the Ministry of Science, Innovation and Universities of the Spanish Government (MCIU) [RTI2018-099589-B-I00], the State Agency of Research (AEI) [RTI2018-099589-B-I00] and the European Regional Development Fund [RTI2018-099589-B-I00]; through the project SEVERUS (Multilevel evaluation of seismic vulnerability and risk mitigation of masonry buildings in resilient historical urban centres [RTI2018-099589-B-I00]; Agència de Gestió d'Ajuts Universitaris i de Recerca; MSc SAHC Consortium scholarship; Sapienza University of Rome.
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- 2022
3. Experimental and Numerical Insights on the In-Plane Behaviour of Urm and Trm-Srg Retrofitted Masonry Walls by Diagonal Compression and Shear-Compression Testing
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Larisa Garcia-Ramonda, Luca Pelà, Pere Roca, and Guido Camata
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- 2023
4. Maskless Patterned Plasma Fabrication of Interdigitated Back Contact Silicon Heterojunction Solar Cells: Characterization and Optimization
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Junkang Wang, Monalisa Ghosh, Karim Ouaras, Dmitri Daineka, Pavel Bulkin, Pere Roca i Cabarrocas, Sergej Filonovich, José Alvarez, and Erik Johnson
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- 2023
5. Microlayer in nucleate boiling seen as Landau-Levich film with dewetting and evaporation
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Tecchio, Cassiano, Zhang, Xiaolong, Cariteau, Benjamin, Zalczer, Gilbert, Cabarrocas, Pere Roca i, Bulkin, Pavel, Charliac, Jérôme, Vassant, Simon, and Nikolayev, Vadim S.
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Fluid Dynamics (physics.flu-dyn) ,FOS: Physical sciences ,Physics - Fluid Dynamics - Abstract
Both experimental and theoretical studies on the microscale and fast physical phenomena occurring during the growth of vapor bubbles in nucleate pool boiling are reported. The focus is on the liquid film of micrometric thickness (``microlayer'') that can form between the heater and the liquid-vapor interface of a bubble on the millisecond time scale. The microlayer strongly affects the macroscale heat transfer and is thus important to be understood. It is shown that the microlayer can be seen as the Landau-Levich film deposited by the bubble foot edge during its receding when the bubble grows. The microlayer profile measured with white-light interferometry, the temperature distribution over the heater, and the bubble shape were observed with synchronized high-speed cameras. The microlayer consists of two regions: a ridge near the contact line followed by a longer and flatter part. The ridge could not be measured because of the intrinsic limitation of interferometry, which is analyzed. The simulations show that the ridge grows over time due to collection of liquid at contact line receding, the theoretical dynamics of which agrees with the experiment. The flatter part of the microlayer is bumped and its physical origin is explained.
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- 2023
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6. Comparison of similitude laws applied to multi-storey masonry structures with flexible diaphragms
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Yohei Endo, Pere Roca, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials
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Estructures de murs ,Similitude law ,Enginyeria civil::Materials i estructures [Àrees temàtiques de la UPC] ,Seismic assessment ,Building and Construction ,Geotechnical Engineering and Engineering Geology ,Masonry ,Shaking table test ,Civil and Structural Engineering ,Numerical analysis - Abstract
This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Earthquake Engineering on 2022, available online at: http://www.tandfonline.com/10.1080/13632469.2022.2040655. The present paper discusses similitude laws employed for the shaking-table tests of masonry structures with flexible diaphragms. Two tasks are tackled. First, the paper presents a literature review on similitude laws. The discussion focuses on Cauchy and Cauchy-Froude laws. Second, numerical analysis is performed to examine the accuracy and adequacy of the aforementioned two laws. Two previously performed shaking-table tests are taken advantage of as the case studies. The paper explores the ideal applications of similitude laws to the shaking table tests of masonry structures with flexible diaphragms by comparing the behaviour between full-scale prototypes and reduced-scale models.
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- 2023
7. Caveolin-1 dolines form a distinct and rapid caveolae-independent mechanoadaptation system
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Fidel-Nicolás Lolo, Nikhil Walani, Eric Seemann, Dobryna Zalvidea, Dácil María Pavón, Gheorghe Cojoc, Moreno Zamai, Christine Viaris de Lesegno, Fernando Martínez de Benito, Miguel Sánchez-Álvarez, Juan José Uriarte, Asier Echarri, Daniel Jiménez-Carretero, Joan-Carles Escolano, Susana A. Sánchez, Valeria R. Caiolfa, Daniel Navajas, Xavier Trepat, Jochen Guck, Christophe Lamaze, Pere Roca-Cusachs, Michael M. Kessels, Britta Qualmann, Marino Arroyo, Miguel A. del Pozo, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya. LACÀN - Mètodes Numèrics en Ciències Aplicades i Enginyeria, Unión Europea. Comisión Europea. H2020, Marie Curie, Ministerio de Ciencia e Innovación (España), European Union Next Generation, Asociación Española Contra el Cáncer, Comunidad de Madrid (España), Fundación La Marató TV3, Fundación La Caixa, Ministerio de Ciencia e Innovación. Centro de Excelencia Severo Ochoa (España), and Fundación ProCNIC
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Biomathematics ,Biologia ,Biomatemàtica ,92 Biology and other natural sciences::92B Mathematical biology in general [Classificació AMS] ,Matemàtiques i estadística::Matemàtica aplicada a les ciències [Àrees temàtiques de la UPC] ,Cell Biology ,Biology ,92 Biology and other natural sciences::92C Physiological, cellular and medical topics [Classificació AMS] - Abstract
In response to different types and intensities of mechanical force, cells modulate their physical properties and adapt their plasma membrane (PM). Caveolae are PM nano-invaginations that contribute to mechanoadaptation, buffering tension changes. However, whether core caveolar proteins contribute to PM tension accommodation independently from the caveolar assembly is unknown. Here we provide experimental and computational evidence supporting that caveolin-1 confers deformability and mechanoprotection independently from caveolae, through modulation of PM curvature. Freeze-fracture electron microscopy reveals that caveolin-1 stabilizes non-caveolar invaginations-dolines-capable of responding to low-medium mechanical forces, impacting downstream mechanotransduction and conferring mechanoprotection to cells devoid of caveolae. Upon cavin-1/PTRF binding, doline size is restricted and membrane buffering is limited to relatively high forces, capable of flattening caveolae. Thus, caveolae and dolines constitute two distinct albeit complementary components of a buffering system that allows cells to adapt efficiently to a broad range of mechanical stimuli. We thank R. Parton (Institute for Molecular Biosciences, Queensland), P. Pilch (Boston University School of Medicine) and L. Liu (Boston University School of Medicine) for kindly providing PTRFKO cells and reagents, S. Casas Tintó for kindly providing SH-Sy5y cells, P. Bassereau (Curie Institute, Paris) for kindly providing OT setup, V. Labrador Cantarero from CNIC microscopy Unit for helping with ImageJ analysis, O. Otto and M. Herbig for providing help with RTDC experiments, S. Berr and K. Gluth for technical assistance in cell culture, F. Steiniger for support in electron tomography, and A. Norczyk Simón for providing pCMV-FLAG-PTRF construct. This project received funding from the European Union Horizon 2020 Research and Innovation Programme through Marie Sklodowska-Curie grant 641639; grants from the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033): SAF2014-51876-R, SAF2017-83130-R co-funded by ‘ERDF A way of making Europe’, PID2020-118658RB-I00, PDC2021-121572-100 co-funded by ‘European Union NextGenerationEU/PRTR’, CSD2009- 0016 and BFU2016-81912-REDC; and the Asociación Española Contra el Cáncer foundation (PROYE20089DELP) all to M.A.d.P. M.A.d.P. is member of the Tec4Bio consortium (ref. S2018/NMT¬4443; Comunidad Autónoma de Madrid/FEDER, Spain), co-recipient with P.R.-C. of grants from Fundació La Marató de TV3 (674/C/2013 and 201936- 30-31), and coordinator of a Health Research consortium grant from Fundación Obra Social La Caixa (AtheroConvergence, HR20-00075). M.S.-A. is recipient of a Ramón y Cajal research contract from MCIN (RYC2020-029690-I). The CNIC Unit of Microscopy and Dynamic Imaging is supported by FEDER ‘Una manera de hacer Europa’ (ReDIB ICTS infrastructure TRIMA@CNIC, MCIN). We acknowledge the support from Deutsche Forschungsgemeinschaft through grants to M.M.K. (KE685/7-1) and B.Q. (QU116/6-2 and QU116/9-1). Work in D.N. laboratory was supported by grants from the European Union Horizon 2020 Research and Innovation Programme through Marie Sklodowska-Curie grant 812772 and MCIN (DPI2017-83721-P). Work in C.L. laboratory was supported by grants from Curie, INSERM, CNRS, Agence Nationale de la Recherche (ANR-17-CE13-0020-01) and Fondation ARC pour la Recherche (PGA1-RF20170205456). Work in P.R.-C. lab is funded by the MCIN (PID2019-110298GB-I00), the EC (H20 20-FETPROACT-01-2016-731957). Work in X.T. lab is funded by the MICIN (PID2021-128635NB-I00), ERC (Adv-883739) and La Caixa Foundation (LCF/PR/HR20/52400004; co-recipient with P.R.-C.). IBEC is recipient of a Severo Ochoa Award of Excellence from the MINECO. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the MCIN and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (grant CEX2020-001041-S funded by MICIN/AEI/10.13039/501100011033). Sí
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- 2022
8. Stiffness-dependent active wetting enables optimal collective cell durotaxis
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Macià Esteve Pallarès, Irina Pi-Jaumà, Isabela Corina Fortunato, Valeria Grazu, Manuel Gómez-González, Pere Roca-Cusachs, Jesus M. de la Fuente, Ricard Alert, Raimon Sunyer, Jaume Casademunt, Xavier Trepat, Generalitat de Catalunya, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Diputación General de Aragón, European Commission, European Research Council, Fundació La Marató de TV3, Fundación 'la Caixa', and Ministerio de Economía y Competitividad (España)
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Migració cel·lular ,General Physics and Astronomy ,Cell migration ,Glicoproteïnes ,Glycoproteins - Abstract
The directed migration of cellular clusters enables morphogenesis, wound healing and collective cancer invasion. Gradients of substrate stiffness direct the migration of cellular clusters in a process called collective durotaxis, but the underlying mechanisms remain unclear. Here we unveil a connection between collective durotaxis and the wetting properties of cellular clusters. We show that clusters of cancer cells dewet soft substrates and wet stiff ones. At intermediate stiffness—at the crossover from low to high wettability—clusters on uniform-stiffness substrates become maximally motile, and clusters on stiffness gradients exhibit optimal durotaxis. Durotactic velocity increases with cluster size, stiffness gradient and actomyosin activity. We demonstrate this behaviour on substrates coated with the cell–cell adhesion protein E-cadherin and then establish its generality on substrates coated with extracellular matrix. We develop an active wetting model that explains collective durotaxis in terms of a balance between in-plane active traction and tissue contractility and out-of-plane surface tension. Finally, we show that the distribution of cluster displacements has a heavy tail, with infrequent but large cellular hops that contribute to durotactic migration. Our study demonstrates a physical mechanism of collective durotaxis, through both cell–cell and cell–substrate adhesion ligands, based on the wetting properties of active droplets., This paper was funded by the Generalitat de Catalunya (AGAUR SGR-2017-01602 to X.T., AGAUR SGR-2017-1061 to J.C., the CERCA Programme and ‘ICREA Academia’ awards to P.R.-C. and J.C.); the Spanish Ministry for Science and Innovation MICCINN/FEDER (PGC2018-099645-B-I00 to X.T., PID2019-110298GB-I00 to P.R.-C., PID2019-108842GB-C21 to J.C., RTI2018-101256-J-I00 and RYC2019-026721-I to R.S., FPU19/05492 to I.P.-J., FPU15/06516 to M.-E.P.); Fondo Social de la DGA (grupos DGA) to V.G. and J.M.d.l.F.; European Research Council (Adv-883739 to X.T.); Fundació la Marató de TV3 (project 201903-30-31-32 to X.T.); the European Commission (H2020-FETPROACT-01-2016-731957 to P.R.-C. and X.T.); the European Union’s Horizon 2020 research and innovation programme (under the Marie Skłodowska-Curie grant agreement no. 797621 to M.G.-G.); the European Foundation for the Study of Chronic Liver Failure (EF-Clif); and the La Caixa Foundation (LCF/PR/HR20/52400004 to P.R.-C. and X.T.). IBEC is the recipient of a Severo Ochoa Award of Excellence from MINECO. R.S. is a Serra Húnter fellow.
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- 2022
9. Cell response to extracellular matrix energy dissipation outweighs rigidity sensing
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Carla Huerta-López, Alejandro Clemente-Manteca, Diana Velázquez-Carreras, Francisco M. Espinosa, Juan G. Sanchez, Pablo Sáez, Álvaro Martínez-del-Pozo, María García-García, Sara Martín-Colomo, Andrea Rodríguez-Blanco, Ricardo Esteban-González, Francisco M. Martín-Zamora, Luis I. Gutierrez-Rus, Ricardo García, Pere Roca-Cusachs, Alberto Elosegui-Artola, Miguel A. del Pozo, Elías Herrero-Galán, Gustavo R. Plaza, and Jorge Alegre-Cebollada
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The mechanical properties of the extracellular matrix (ECM) determine cell differentiation, proliferation and migration through mechanoresponsive proteins including YAP. However, how different mechanical signals cooperate, synergize or compete to steer cell behavior remains poorly understood. Here, we have examined competition between the two major ECM mechanical cues, i.e. rigidity, which activates cell mechanosensing, and viscous energy dissipation, which reduces stiffness blunting cell mechanotransduction. To trigger competition, we have engineered protein hydrogels allowing concomitant modulation of stiffness and viscosity by mechanisms characteristic of native ECM. Culturing cells on these hydrogels, we have found that substrate energy dissipation attenuates YAP mechanosensing prevailing over stiffness cues. Hampered YAP activation on more dissipative substrates correlates with faster actin flow and smaller focal adhesions. Mechanistically, inhibition of actomyosin contractility reverses the outcome of the competition between rigidity and energy dissipation. Our results highlight the dominating contribution of substrate viscosity to the biology of the cell.
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- 2022
10. Correction: Loss of E-cadherin leads to Id2-dependent inhibition of cell cycle progression in metastatic lobular breast cancer
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Max A. K. Rätze, Thijs Koorman, Thijmen Sijnesael, Blessing Bassey-Archibong, Robert van de Ven, Lotte Enserink, Daan Visser, Sridevi Jaksani, Ignacio Viciano, Elvira R. M. Bakker, François Richard, Andrew Tutt, Lynda O’Leary, Amanda Fitzpatrick, Pere Roca-Cusachs, Paul J. van Diest, Christine Desmedt, Juliet M. Daniel, Clare M. Isacke, and Patrick W. B. Derksen
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Cancer Research ,Genetics ,Molecular Biology - Published
- 2022
11. Caveolae couple mechanical stress to integrin recycling and activation
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Fidel-Nicolás Lolo, Dácil María Pavón, Araceli Grande, Alberto Elósegui Artola, Valeria Inés Segatori, Sara Sánchez, Xavier Trepat, Pere Roca-Cusachs, Miguel A del Pozo, Unión Europea. Comisión Europea. H2020, Marie Curie, Ministerio de Ciencia e Innovación (España), Unión Europea. Fondo Europeo de Desarrollo Regional (FEDER/ERDF), Asociación Española Contra el Cáncer, European Union NextGeneration, Fundación La Caixa, Instituto de Salud Carlos III, Fundación ProCNIC, and Ministerio de Ciencia e Innovación. Centro de Excelencia Severo Ochoa (España)
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Integrins ,Mice ,General Immunology and Microbiology ,General Neuroscience ,Integrin beta1 ,Cell Adhesion ,Animals ,General Medicine ,Stress, Mechanical ,Fibroblasts ,Caveolae ,General Biochemistry, Genetics and Molecular Biology - Abstract
Cells are subjected to multiple mechanical inputs throughout their lives. Their ability to detect these environmental cues is called mechanosensing, a process in which integrins play an important role. During cellular mechanosensing, plasma membrane (PM) tension is adjusted to mechanical stress through the buffering action of caveolae; however, little is known about the role of caveolae in early integrin mechanosensing regulation. Here, we show that Cav1KO fibroblasts increase adhesion to FN-coated beads when pulled with magnetic tweezers, as compared to wild type fibroblasts. This phenotype is Rho-independent and mainly derived from increased active β1-integrin content on the surface of Cav1KO fibroblasts. Florescence recovery after photobleaching analysis and endocytosis/recycling assays revealed that active β1-integrin is mostly endocytosed through the clathrin independent carrier/glycosylphosphatidyl inositol (GPI)-enriched endocytic compartment pathway and is more rapidly recycled to the PM in Cav1KO fibroblasts, in a Rab4 and PM tension-dependent manner. Moreover, the threshold for PM tension-driven β1-integrin activation is lower in Cav1KO mouse embryonic fibroblasts (MEFs) than in wild type MEFs, through a mechanism dependent on talin activity. Our findings suggest that caveolae couple mechanical stress to integrin cycling and activation, thereby regulating the early steps of the cellular mechanosensing response.Cells can physically sense their immediate environment by pulling and pushing through integrins, a type of proteins which connects the inside and outside of a cell by being studded through the cellular membrane. This sensing role can only be performed when integrins are in an active state. Two main mechanisms regulate the relative amount of active integrins: one controls the activation of the proteins already at the cell surface; the other, known as recycling, impacts how many new integrins are delivered to the membrane. Both processes are affected by changes in cell membrane tension, which is itself controlled by dimples (or ‘caveolae’ – little caves in Latin) present in the cell surface. Caveolae limit acute changes in tension by taking in (pinching off the dimples) or releasing (dimples flattening) segments of the membrane. However, it is still unclear how integrins and caveolae mechanically interact to regulate the ability for a cell to read its environment. To understand this process, Lolo et al. focused on mouse cells genetically manipulated to not build caveolae on their surfaces, and which cannot properly sense mechanical changes in their surroundings. These were exposed to beads covered in an integrin-binding protein and manipulated using magnetic tweezers. The manipulation showed that mutated cells bound to the beads more strongly than non-modified cells, indicating that they had more active integrins on their surface. This change was due to both an accelerated recycling mechanism (which resulted in more integrin being brought at the surface) and an increase in integrin activation (which was triggered by a higher membrane tension). Caveolae therefore couple mechanical inputs to integrin recycling and activation. Healthy tissues rely on cells correctly sensing physical changes in their environment so they can mount an appropriate response. This ability, for example, is altered in cancerous cells which start to form tumours. The findings by Lolo et al. bring together physics and biology to provide new insights into the potential mechanisms causing such impairments.
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- 2022
12. Author response: Caveolae couple mechanical stress to integrin recycling and activation
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Fidel-Nicolás Lolo, Dácil María Pavón, Araceli Grande, Alberto Elósegui Artola, Valeria Inés Segatori, Sara Sánchez, Xavier Trepat, Pere Roca-Cusachs, and Miguel A del Pozo
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- 2022
13. Cardiac fibroblasts and mechanosensation in heart development, health and disease
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Maurizio Pesce, Georg N. Duda, Giancarlo Forte, Henrique Girao, Angel Raya, Pere Roca-Cusachs, Joost P. G. Sluijter, Carsten Tschöpe, and Sophie Van Linthout
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Cardiology and Cardiovascular Medicine - Abstract
The term 'mechanosensation' describes the capacity of cells to translate mechanical stimuli into the coordinated regulation of intracellular signals, cellular function, gene expression and epigenetic programming. This capacity is related not only to the sensitivity of the cells to tissue motion, but also to the decryption of tissue geometric arrangement and mechanical properties. The cardiac stroma, composed of fibroblasts, has been historically considered a mechanically passive component of the heart. However, the latest research suggests that the mechanical functions of these cells are an active and necessary component of the developmental biology programme of the heart that is involved in myocardial growth and homeostasis, and a crucial determinant of cardiac repair and disease. In this Review, we discuss the general concept of cell mechanosensation and force generation as potent regulators in heart development and pathology, and describe the integration of mechanical and biohumoral pathways predisposing the heart to fibrosis and failure. Next, we address the use of 3D culture systems to integrate tissue mechanics to mimic cardiac remodelling. Finally, we highlight the potential of mechanotherapeutic strategies, including pharmacological treatment and device-mediated left ventricular unloading, to reverse remodelling in the failing heart.
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- 2022
14. Author Reply to Peer Reviews of Mechanical control of the mammalian circadian clock via YAP/TAZ and TEAD
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Juan F. Abenza, Leone Rossetti, Maleke Mouelhi, Javier Burgues, Ion Andreu, Keith Kennedy, Pere Roca-Cusachs, Santiago Marco, Jordi Garcia Ojalvo, and Xavier Trepat
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- 2022
15. Epithelial cell cluster size affects force distribution in response to EGF-induced collective contractility
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Chiara Zambarda, Carlos Pérez González, Andreas Schoenit, Nisha Veits, Clara Schimmer, Raimund Jung, Dirk Ollech, Joel Christian, Pere Roca-Cusachs, Xavier Trepat, and Elisabetta Ada Cavalcanti-Adam
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Cèl·lules epitelials ,Interacció cel·lular ,Cancer cells ,Histology ,Cèl·lules ,Cells ,Epidermal growth factor ,Proteins ,Epithelial cells ,Cell Biology ,General Medicine ,Pathology and Forensic Medicine ,Contracció muscular ,Muscle contraction ,Cell interaction ,Cèl·lules canceroses ,Factor de creixement epidèrmic ,Proteïnes - Abstract
Several factors present in the extracellular environment regulate epithelial cell adhesion and dynamics. Among them, growth factors such as EGF, upon binding to their receptors at the cell surface, get internalized and directly activate the acto-myosin machinery. In this study we present the effects of EGF on the contractility of epithelial cancer cell colonies in confined geometry of different sizes. We show that the extent to which EGF triggers contractility scales with the cluster size and thus the number of cells. Moreover, the collective contractility results in a radial distribution of traction forces, which are dependent on integrin β1 peripheral adhesions and transmitted to neighboring cells through adherens junctions. Taken together, EGF-induced contractility acts on the mechanical crosstalk and linkage between the cell-cell and cell-matrix compartments, regulating collective responses.
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- 2022
16. In search of a softer environment
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Amy E M, Beedle and Pere, Roca-Cusachs
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- 2022
17. Self-formation of SiGe oxide, Ge, and void multilayers via thermal oxidation of hydrogenated epitaxial SiGe films
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Junyang An, Ruiling Gong, Xinyu Li, Ileana Florea, Lise Watrin, Pere Roca i Cabarrocas, and Wanghua Chen
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Condensed Matter Physics ,Instrumentation ,Surfaces, Coatings and Films - Published
- 2023
18. Effect of cross section aspect ratio and bearing surfaces treatment on the compressive strength of solid fired clay brick specimens
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Albert Cabané, Luca Pelà, Pere Roca, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials
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Capping ,Grinding ,Handmade bricks ,Bearing surface ,Solid fired clay bricks ,Enginyeria civil::Materials i estructures [Àrees temàtiques de la UPC] ,Compressive strength ,Building and Construction ,Maons ,Masonry -- Testing ,Bricks ,Estructures de murs ,General Materials Science ,Superficial treatment ,PTFE ,Masonry ,Loading surface ,Confinement ,Civil and Structural Engineering - Abstract
This study addresses the evaluation of the confinement effect in the experimental determination of compressive strength in solid fired clay units. The experimental campaign has focused on two different types of solid fired clay bricks, namely mechanically extruded and handmade, with a total amount of 458 specimens. The research considers different standard specimens, such as whole or half brick, and 100 × 100 × 40 mm3 specimen, and nonstandard 40 × 40 × 40 mm3 specimen, subjected to different standard bearing surface treatments, i.e. grinding, capping with cement mortar or gypsum plaster, placing with birch plywood or fibreboard. Additionally, two novel bearing surface treatments are proposed, i.e. covering with gypsum powder, and placing two oiled PTFE leaves. The experimental campaign has focused on four main aspects. First, the evaluation of the compressive strength value in specimens with hardening response. Second, the influence of the cross section’s aspect ratio, defined as the ratio between the specimen’s length and width. Third, the influence of the bearing surface treatment on the determination of the compressive strength. Fourth, the evaluation of the standard compressive strength through the comparison amongst reference standards. The results highlight and quantify the different factors that influence the confinement, while detecting differences depending on the manufacturing process of the unit. In addition, the results reveal the use of oiled PTFE leaves as a promising and fast possibility of low boundary friction to obtain the strength regardless of the specimen shape. The authors gratefully acknowledge the financial support from the Ministry of Science, Innovation and Universities of the Spanish Government (MCIU), the State Agency of Research (AEI) as well as that of the ERDF (European Regional Development Fund) through the project SEVERUS (Multilevel evaluation of seismic vulnerability and risk mitigation of masonry buildings in resilient historical urban centres, ref. Num. RTI2018-099589-B-I00). Support from MCIU through a predoctoral grant awarded to the first author is also gratefully acknowledged.
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- 2023
19. Ultrahigh Incorporation of Tin in SiSn Nanowires Grown via In-Plane Solid-Liquid-Solid Mechanism
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Edy Azrak, Zhaoguo Xue, Shuai Liu, Wanghua Chen, Celia Castro, Sébastien Duguay, Philippe Pareige, Linwei Yu, and Pere Roca i Cabarrocas
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General Physics and Astronomy ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Surfaces, Coatings and Films - Published
- 2023
20. Mechanical compartmentalization of the intestinal organoid enables crypt folding and collective cell migration
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Gerardo Ceada, Marija Matejčić, Andrew G. Clark, Marino Arroyo, Anghara Menendez, Denis Krndija, Venkata Ram Gannavarapu, Pere Roca-Cusachs, Natalia Castro, Manuel Gomez-Gonzalez, Xavier Trepat, Adrián Álvarez-Varela, Francesco Greco, Carlos Pérez-González, Danijela Matic Vignjevic, Sohan Kale, Eduard Batlle, Universitat Politècnica de Catalunya. Centre Específic de Recerca de Mètodes Numèrics en Ciències Aplicades i Enginyeria, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. LACÀN - Mètodes Numèrics en Ciències Aplicades i Enginyeria
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Biomatemàtica ,Crypt ,Matemàtiques i estadística::Matemàtica aplicada a les ciències [Àrees temàtiques de la UPC] ,Numerical analysis--Simulation methods ,Extracellular matrix ,03 medical and health sciences ,0302 clinical medicine ,Organoid ,Cell migration ,65 Numerical analysis::65C Probabilistic methods, simulation and stochastic differential equations [Classificació AMS] ,030304 developmental biology ,Biomathematics ,Anàlisi numèrica ,Intestins ,0303 health sciences ,Migració cel·lular ,Chemistry ,Matemàtiques i estadística::Anàlisi numèrica::Mètodes numèrics [Àrees temàtiques de la UPC] ,92 Biology and other natural sciences::92B Mathematical biology in general [Classificació AMS] ,Apical constriction ,Cell Biology ,Compartmentalization (psychology) ,Intestinal epithelium ,Cell biology ,Intestines ,Folding (chemistry) ,030220 oncology & carcinogenesis ,Self-healing hydrogels - Abstract
Intestinal organoids capture essential features of the intestinal epithelium such as crypt folding, cellular compartmentalization and collective movements. Each of these processes and their coordination require patterned forces that are at present unknown. Here we map three-dimensional cellular forces in mouse intestinal organoids grown on soft hydrogels. We show that these organoids exhibit a non-monotonic stress distribution that defines mechanical and functional compartments. The stem cell compartment pushes the extracellular matrix and folds through apical constriction, whereas the transit amplifying zone pulls the extracellular matrix and elongates through basal constriction. The size of the stem cell compartment depends on the extracellular-matrix stiffness and endogenous cellular forces. Computational modelling reveals that crypt shape and force distribution rely on cell surface tensions following cortical actomyosin density. Finally, cells are pulled out of the crypt along a gradient of increasing tension. Our study unveils how patterned forces enable compartmentalization, folding and collective migration in the intestinal epithelium.
- Published
- 2021
21. Selected Papers from the 12th International Conference on Structural Analysis of Historical Constructions (SAHC 2021)
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Paulo B. Lourenço, Pere Roca, and Luca Pelà
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Visual Arts and Performing Arts ,Architecture ,Conservation - Published
- 2023
22. Influence of the Electron Beam and the Choice of Heating Membrane on the Evolution of Si Nanowires’ Morphology in In Situ TEM
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Ya Shen, Xuechun Zhao, Ruiling Gong, Eric Ngo, Jean-Luc Maurice, Pere Roca i Cabarrocas, and Wanghua Chen
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electron beam irradiation ,silicon nanowire ,growth ,TEM ,General Materials Science - Abstract
We used in situ transmission electron microscopy (TEM) to observe the dynamic changes of Si nanowires under electron beam irradiation. We found evidence of structural evolutions under TEM observation due to a combination of electron beam and thermal effects. Two types of heating holders were used: a carbon membrane, and a silicon nitride membrane. Different evolution of Si nanowires on these membranes was observed. Regarding the heating of Si nanowires on a C membrane at 800 °C and above, a serious degradation dependent on the diameter of the Si nanowire was observed under the electron beam, with the formation of Si carbide. When the membrane was changed to Si nitride, a reversible sectioning and welding of the Si nanowire was observed.
- Published
- 2022
- Full Text
- View/download PDF
23. Regulation of cell dynamics by rapid transport of integrins through the biosynthetic pathway
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Martina Lerche, Mathilde Mathieu, Lene Malerød, Nina Marie Pedersen, Hellyeh Hamidi, Megan Chastney, Bart Marlon Herwig Bruininks, Shreyas Kaptan, Guillaume Jacquemet, Ilpo Vattulainen, Pere Roca-Cusachs, Andreas Brech, Franck Perez, Gaelle Boncompain, Stéphanie Miserey, and Johanna Ivaska
- Abstract
Cells sense and respond to the extracellular matrix (ECM) milieu through integrin proteins. Integrin availability on the plasma membrane, regulated by endosomal receptor uptake and recycling, has been extensively studied and regulates cell dynamics in various normal and pathological contexts1–5. In contrast, the role of integrin transport through the biosynthetic pathway has been considered primarily as a mechanism to replenish the receptor pool and too slow to influence cell dynamics6. Here, we adopted the RUSH (Retention Using Selective Hooks) assay to synchronize integrin anterograde transport from the endoplasmic reticulum (ER), allowing spatial and temporal analysis of newly synthesized receptor traffic. We observe that the delivery of new integrins to the plasma membrane is polarized in response to specific ECM ligands, facilitates integrin recruitment specifically to the membrane-proximal tip of focal adhesions (FA) and contributes to cell protrusion and FA growth. We explain the augmented adhesion growth using a computational molecular clutch model7, where increased integrin availability drives recruitment of additional integrins. Notably, a subset of newly synthesized integrins undergo rapid traffic from the ER to the cell surface to facilitate localized cell spreading, seemingly bypassing the Golgi. This unconventional secretion is dependent on cell adhesion and mediated by Golgi reassembling stacking proteins (GRASPs) association with the PDZ-binding motif in the integrin α5 cytoplasmic tail. This spatially targeted delivery of integrins through the biosynthetic pathway may propel cell dynamics by rapidly altering adhesion receptor availability, providing cells with an additional degree of plasticity to respond to their environment.
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- 2022
24. Mechanical force application to the nucleus regulates nucleocytoplasmic transport
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Ion Andreu, Ignasi Granero-Moya, Nimesh R. Chahare, Kessem Clein, Marc Molina-Jordán, Amy E. M. Beedle, Alberto Elosegui-Artola, Juan F. Abenza, Leone Rossetti, Xavier Trepat, Barak Raveh, Pere Roca-Cusachs, Universitat Politècnica de Catalunya. Doctorat en Matemàtica Aplicada, and Universitat Politècnica de Catalunya. LACÀN - Mètodes Numèrics en Ciències Aplicades i Enginyeria
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Cell biology ,Cytoplasm ,Cèl·lules -- Biologia ,Moviments mecànics ,Proteins ,Nuclear energy ,Cell Biology ,Transformació cel·lular ,Citoplasma ,Matemàtiques i estadística::Anàlisi numèrica [Àrees temàtiques de la UPC] ,Cell transformation ,65 Numerical analysis [Classificació AMS] ,Energia nuclear ,Enginyeria biomèdica::Biomecànica [Àrees temàtiques de la UPC] ,Mechanical movements ,Proteïnes - Abstract
Mechanical force controls fundamental cellular processes in health and disease, and increasing evidence shows that the nucleus both experiences and senses applied forces. Such forces can lead to the nuclear translocation of proteins, but whether force controls nucleocytoplasmic transport, and how, remains unknown. Here we show that nuclear forces differentially control passive and facilitated nucleocytoplasmic transport, setting the rules for the mechanosensitivity of shuttling proteins. We demonstrate that nuclear force increases permeability across nuclear pore complexes, with a dependence on molecular weight that is stronger for passive than for facilitated diffusion. Owing to this differential effect, force leads to the translocation of cargoes into or out of the nucleus within a given range of molecular weight and affinity for nuclear transport receptors. Further, we show that the mechanosensitivity of several transcriptional regulators can be both explained by this mechanism and engineered exogenously by introducing appropriate nuclear localization signals. Our work unveils a mechanism of mechanically induced signalling, probably operating in parallel with others, with potential applicability across signalling pathways.
- Published
- 2022
25. Wafer-Scale Pulsed Laser Deposition of ITO for Silicon Heterojunction Solar Cells: Reduced Damage vs Interfacial Resistance
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Yury Smirnov, Pierre-Alexis Repecaud, Leonard Tutsch, Ileana Florea, Pere Roca i Cabarrocas, Martin Bivour, and Monica Morales-Masis
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- 2022
26. Mapping mechanical stress in curved epithelia of designed size and shape
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Ariadna Marín-Llauradó, Sohan Kale, Adam Ouzeri, Raimon Sunyer, Alejandro Torres-Sánchez, Ernest Latorre, Manuel Gómez-González, Pere Roca-Cusachs, Marino Arroyo, and Xavier Trepat
- Abstract
The function of organs such as lungs, kidneys and mammary glands relies on the three-dimensional geometry of their epithelium. To adopt shapes such as spheres, tubes and ellipsoids, epithelia generate mechanical stresses that are generally unknown. Here we engineered curved epithelial monolayers of controlled size and shape and mapped their state of stress. We designed pressurized epithelia with circular, rectangular and ellipsoidal footprints. We developed a computational method to map the stress tensor in these epithelia. This method establishes a direct correspondence between epithelial shape and mechanical stress without assumptions of material properties. In epithelia with spherical geometry spanning more than one order of magnitude in radius, we show that stress weakly increases with areal strain in a size-independent manner. In epithelia with rectangular and ellipsoidal cross-section we found pronounced stress anisotropies consistent with the asymmetric distribution of tractions measured at the cell-substrate contact line. In these anisotropic profiles, cell shape tended to align with the direction of maximum principal stress but this alignment was non-universal and depended on epithelial geometry. Besides interrogating the fundamental mechanics of epithelia over a broad range of sizes and shapes, our approach will enable a systematic study of how geometry and stress influence epithelial fate and function in three-dimensions.
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- 2022
27. Single‐Crystal Nanowire Cesium Tin Triiodide Perovskite Solar Cell
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Letian Dai, Pere Roca i Cabarrocas, Huaxia Ban, Zhiguo Zhang, Qiang Sun, Xiongjie Li, Anjie Gu, Wanpeng Yang, Haixuan Yu, Yan Shen, and Mingkui Wang
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Biomaterials ,General Materials Science ,General Chemistry ,Biotechnology - Published
- 2023
28. Cell response to substrate energy dissipation outweighs rigidity sensing
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Jorge Alegre-Cebollada, Carla Huerta-Lopez, Alejandro Clemente-Manteca, Diana Velazquez-Carreras, Francisco M. Espinosa, Pablo Saez, Alvaro Martinez-del-Pozo, Maria Garcia-Garcia, Sara Martin-Colomo, Ricardo Garcia, Pere Roca-Cusachs, Alberto Elosegui-Artola, Miguel A. del Pozo, Elías Herrero-Galán, and Gustavo R. Plaza
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Biophysics - Published
- 2023
29. In search of a softer environment
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Amy E. M. Beedle and Pere Roca-Cusachs
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science ,General Chemistry ,Condensed Matter Physics - Published
- 2022
30. The laminin-keratin link shields the nucleus from mechanical deformation and signalling
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Zanetta Kechagia, Pablo Sáez, Manuel Gómez-González, Martín Zamarbide, Ion Andreu, Thijs Koorman, Amy E.M. Beedle, Patrick W.B. Derksen, Xavier Trepat, Marino Arroyo, and Pere Roca-Cusachs
- Abstract
The mechanical properties of the extracellular matrix (ECM) dictate tissue behaviour. In epithelial tissues, laminin is both a very abundant ECM component, and a key supporting element. Here we show that laminin hinders the mechanoresponses of breast epithelial cells by shielding the nucleus from mechanical deformation. Coating substrates with laminin-111, unlike fibronectin or collagen I, impairs cell response to substrate rigidity, and YAP nuclear localization. Blocking the laminin-specific integrin β4 increases nuclear YAP ratios in a rigidity dependent manner, without affecting cell forces or focal adhesions. By combining mechanical perturbations and mathematical modelling, we show that β4 integrins establish a mechanical linkage between the substrate and the keratin cytoskeleton, which stiffens the network and shields the nucleus from actomyosin-mediated mechanical deformation. In turn, this affects nuclear YAP mechanoresponses and chromatin methylation. Our results demonstrate a mechanism by which tissues can regulate their sensitivity to mechanical signals.
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- 2022
31. Mechanical control of the mammalian circadian clock via YAP/TAZ and TEAD
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Juan F. Abenza, Leone Rossetti, Malèke Mouelhi, Javier Burgués, Ion Andreu, Keith Kennedy, Pere Roca-Cusachs, Santiago Marco, Jordi García-Ojalvo, and Xavier Trepat
- Abstract
SummaryCircadian rhythms are a key survival mechanism that dictates biological activity according to the day-night cycle. In animals, cell-autonomous circadian clocks can be found in nearly every cell type and are subjected to multi-layered regulation. Although these peripheral clocks are remotely controlled by the master clock in the brain, they are also sensitive to their immediate mechano-chemical microenvironment. Whereas the mechanisms by which biochemical signalling controls the circadian clock at the single cell level are increasingly well understood, mechanisms underlying regulation by mechanical cues are still unknown. Here we show that the circadian clock in fibroblasts is regulated mechanically through YAP/TAZ and TEAD. We use high-throughput analysis of single-cell circadian rhythms and apply controlled mechanical, biochemical, and genetic perturbations to study the expression of the clock gene Rev-erbα. We observe that Rev-erbα circadian oscillations are disrupted concomitantly with the translocation of YAP/TAZ to the nucleus. By targeted mutations and tuning expression levels of YAP we identify TEAD as the transcriptional effector of this mechanosensitive regulatory pathway. Our findings establish a mechanism that links cell mechanobiology and the circadian clock, which could contribute to explain the circadian impairment observed in cancer and ageing, where the regulation of the mechanical environment and YAP/TAZ is lost.
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- 2022
32. Validation of non-linear equivalent-frame models for irregular masonry walls
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Guido Camata, Corrado Marano, Vincenzo Sepe, Enrico Spacone, Rossella Siano, Massimo Petracca, Pere Roca, Luca Pelà, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials
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Micromodeling ,Unreinforced masonry walls ,Estructures de murs ,Enginyeria civil::Materials i estructures [Àrees temàtiques de la UPC] ,Masonry structures ,Non-linear static analysis ,Masonry ,Seismic vulnerability ,Equivalent-frame models ,Civil and Structural Engineering - Abstract
This article compares the results obtained from the analyses of seven two-story masonry walls with an asymmetric arrangement of the openings. The walls are modelled with finite elements detailed micromodels and equivalent frame models. The equivalent frame model reliability is evaluated by comparing the results obtained with the two modelling strategies assuming the detailed micromodel’s results as reference. Namely, the equivalent frame models of the walls, subjected to nonlinear static analyses, were developed in Scientific Toolkit for OpenSees (STKO) and the OpenSees framework using a macroelement, widely accepted by the literature. The macroelement is based on the idealization of the equivalent frame model with fiber modeling of wall panels to capture bending behavior and a phenomenological law to describe shear behavior. It also provides a model for comparison and validation able to correctly describe the nonlinear behavior of fragile materials that exhibit softening in the response. The micromodeling approach was used as the reference as it is particularly efficient from a computation point of view. The numerical models were validated by comparing pseudo-static experimental tests present in the literature concerning walls with a symmetric arrangement of openings. After the preliminary calibration, the numerical comparisons of the irregular walls generally demonstrate a good correspondence between the equivalent frame model and finite element results. The most relevant differences arise for the walls with masonry panels that exhibit a mixed compression-shear damage mechanism because the simplified frame model cannot capture both behaviors, as it privileges the mechanism that activates first. The differences between the maximum shears, however, range from approximately 1% to 12%. The present research has received financial support from the University “G. D’Annunzio” of Chieti-Pescara and from the ReLUIS program 2014-2021. The last two authors gratefully acknowledge the financial support from the Ministry of Science, Innovation and Universities of the Spanish Government (MCIU), the State Agency of Research (AEI), as well as that of the ERDF (European Regional Development Fund) through the project SEVERUS (Multilevel evaluation of seismic vulnerability and risk mitigation of masonry buildings in resilient historical urban centres, ref. num. RTI2018-099589-B-I00). Peer Reviewed Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.4 - Redoblar els esforços per a protegir i salvaguardar el patrimoni cultural i natural del món Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.5 - Per a 2030, reduir de forma significativa el nombre de morts causades per desastres, inclosos els relacionats amb l’aigua, i de persones afectades per aquests, i reduir substancialment les pèrdues econòmiques directes causades per desastres relacionades amb el producte interior brut mundial, fent un èmfasi especial en la protecció de les persones pobres i de les persones en situacions de vulnerabilitat Objectius de Desenvolupament Sostenible::13 - Acció per al Clima Objectius de Desenvolupament Sostenible::13 - Acció per al Clima::13.1 - Enfortir la resiliència i la capacitat d’adaptació als riscos relacionats amb el clima i els desastres naturals a tots els països
- Published
- 2022
33. Hydrogen Plasma-Assisted Growth of Gold Nanowires
- Author
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Bozhi Tian, Sébastien Duguay, Wanghua Chen, Zhen Zheng, Junyang An, Edy Azrak, Antonino Foti, Simona Moldovan, Philippe Pareige, Chantal Karam, Vishnu Nair, Jean-Luc Maurice, Pere Roca i Cabarrocas, Ruiling Gong, Ningbo University (NBU), Laboratoire de physique des interfaces et des couches minces [Palaiseau] (LPICM), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Groupe de physique des matériaux (GPM), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), University of Chicago, Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut Européen des membranes (IEM), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), and Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)
- Subjects
Amorphous silicon ,Materials science ,Silicon ,Nanowire ,chemistry.chemical_element ,Nanotechnology ,engineering.material ,010402 general chemistry ,01 natural sciences ,chemistry.chemical_compound ,Coating ,Etching (microfabrication) ,General Materials Science ,Dewetting ,[INFO.INFO-BT]Computer Science [cs]/Biotechnology ,Thin film ,ComputingMilieux_MISCELLANEOUS ,010405 organic chemistry ,Photothermal effect ,General Chemistry ,Condensed Matter Physics ,3. Good health ,0104 chemical sciences ,chemistry ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,engineering - Abstract
International audience; Because of their innocuity, Au nanowires present an interesting field of applications in biology and, particularly, in cancer therapy. Since their morphology and distribution can greatly affect their performances, being able to control their mode of growth is important. Various elaboration techniques including “top-down” and “bottom-up” approaches have been developed. In this work, we propose an efficient maskless method to grow Au nanowires with the help of hydrogen plasma treatment of Au thin films. We have been able to grow Au nanowires by taking advantage of spinodal dewetting of an Au thin film and the supply of silicon radicals resulting from hydrogen plasma etching of amorphous silicon coating the walls of the reactor. A variety of techniques have been applied to study the microstructure and the optical properties of Au nanowires. A strong photothermal effect of Au nanowires has been demonstrated with the help of visible laser light. In order to study the nanowire growth, the transport of Au atoms is discussed, and a growth mechanism is proposed.
- Published
- 2020
34. Mechanical strain stimulates COPII-dependent trafficking via Rac1
- Author
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Santosh Phuyal, Elena Djaerff, Anabel-Lise Le Roux, Martin J. Baker, Daniela Fankhauser, Sayyed Jalil Mahdizadeh, Veronika Reiterer, Jennifer C. Kahlhofer, David Teis, Marcelo G. Kazanietz, Stephan Geley, Leif Eriksson, Pere Roca-Cusachs, and Hesso Farhan
- Abstract
Secretory trafficking from the endoplasmic reticulum (ER) is subject to regulation by extrinsic and intrinsic factors. While much of the focus has been on biochemical triggers, little is known whether and how the ER is subject to regulation by mechanical signals. Here, we show that COPII-dependent ER-export is regulated by mechanical strain. Mechanotransduction to the ER was mediated via a previously unappreciated ER-localized pool of the small GTPase Rac1. Mechanistically, we show that Rac1 interacts with the small GTPase Sar1 to drive budding of COPII carriers and stimulate ER-to-Golgi transport. Altogether, we establish an unprecedented link between mechanical strain and export from the ER.
- Published
- 2022
35. Modelling of in-plane seismic behaviour of one-way steel or timber jack arch floors in existing buildings: application to the Eixample district of Barcelona
- Author
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Sara Dimovska, Savvas Saloustros, Luca Pelà, Pere Roca, Universitat Politècnica de Catalunya. Doctorat en Enginyeria de la Construcció, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials
- Subjects
Orthotropic Floor ,Finite Element Analysis ,One-way Floor ,Steel Beam ,Seismic Vulnerability ,Risc sísmic ,In-plane Stiffness ,Tile Vault ,Pushover Analysis ,Unreinforced Masonry Building ,Timber Beam ,Earthquake hazard analysis ,Enginyeria civil::Geotècnia::Sismologia [Àrees temàtiques de la UPC] ,Civil and Structural Engineering - Abstract
The type of floor system has a decisive role in the seismic performance of unreinforced masonry buildings. The in-plane stiffness of the floors has to be adequately represented in the numerical modelling of existing buildings, as it can influence their seismic capacity. This paper investigates the seismic behaviour of one-way arch floor systems composed of steel or timber beams, and ceramic tile vaults. The main objective of the research is to provide a numerical procedure for the simplified modelling of jack arch floor systems in the seismic assessment of unreinforced masonry buildings. The presented approach aims to provide values for the orthotropic properties of simplified floor models composed of elastic 2D shell elements. The orthotropic elastic properties are computed and calibrated by means of comparisons with detailed 3D nonlinear models of the floors. The case study is a multi-storey existing masonry building of the historical “Eixample” district in Barcelona, which includes one-way arch floor systems. The Finite Element Method has been used for the numerical simulation of the seismic performance through nonlinear static (pushover) analyses. The results of the study contribute to a better understanding of the effect of the behaviour of one-way floors with steel or timber beams and tile vaults on the seismic response of masonry buildings. This work provides indicative values for the proper modelling of these particular floor slabs. The proposed methodology is also applicable to the numerical simulation of any other one-way floor system. The authors gratefully acknowledge the financial support from the Ministry of Science, Innovation and Universities of the Spanish Government (MCIU), the State Agency of Research (AEI), as well as that of the ERDF (European Regional Development Fund) through the project SEVERUS (Multilevel evaluation of seismic vulnerability and risk mitigation of masonry buildings in resilient historical urban centres, ref. num. RTI2018-099589-B-I00). The first author gratefully acknowledges the AGAUR agency of the Generalitat de Catalunya for the financial support of her predoctoral grant. Peer Reviewed Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.4 - Redoblar els esforços per a protegir i salvaguardar el patrimoni cultural i natural del món Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.5 - Per a 2030, reduir de forma significativa el nombre de morts causades per desastres, inclosos els relacionats amb l’aigua, i de persones afectades per aquests, i reduir substancialment les pèrdues econòmiques directes causades per desastres relacionades amb el producte interior brut mundial, fent un èmfasi especial en la protecció de les persones pobres i de les persones en situacions de vulnerabilitat Objectius de Desenvolupament Sostenible::13 - Acció per al Clima Objectius de Desenvolupament Sostenible::13 - Acció per al Clima::13.1 - Enfortir la resiliència i la capacitat d’adaptació als riscos relacionats amb el clima i els desastres naturals a tots els països Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles
- Published
- 2022
- Full Text
- View/download PDF
36. Simplified numerical approach for the structural analysis of monumental historical aggregates: the case study of Certosa di Calci
- Author
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Irene Puncello, Silvia Caprili, Pere Roca, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials
- Subjects
Finite element analysis ,Enginyeria civil::Materials i estructures [Àrees temàtiques de la UPC] ,Building and Construction ,Geotechnical Engineering and Engineering Geology ,Geophysics ,Estructures de murs ,Masonry -- Mathematical models ,Monumental historical buildings ,Simplified modelling ,Cultural heritage ,Masonry structure ,Civil and Structural Engineering - Abstract
The final publication is available at Springer via http://dx.doi.org/10.1007/s10518-022-01397-w Monumental historical buildings are worldwide recognized as a fundamental component of the World Cultural Heritage to be preserved for future generations. Their structural performance analysis needs to face challenging issues such as the usually limited initial knowledge, the generally large dimensions, and the great structural complexity coming from overlapped construction phases over centuries. The structural behavior of historical constructions, therefore, differs from ordinary buildings, since resulting from the interaction of different parts, recognizable as ‘structural units’. A methodology accounting for all the peculiarities of monumental masonry buildings is proposed with reference to the specific case study of La Certosa di Calci (Italy). The monumental cluster is ideally decomposed into its structural units based on a preliminary knowledge phase, allowing to perform detailed structural analyses only on selected areas without resorting to a cumbersome and time demanding global model. The aggregate-effect influence over the structural behavior of a single unit is investigated by means of nonlinear analysis performed on different configurations. Achieved results are accurately analyzed, finally proposing a simplified model where one structural unit is represented through a FEM model and the interaction effects due to the adjacent portions are simulated through a calibrated spring system.
- Published
- 2022
37. Experimental cyclic behaviour of shear masonry walls reinforced with single and double layered Steel Reinforced Grout
- Author
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Larisa Garcia-Ramonda, Luca Pelà, Pere Roca, Guido Camata, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials
- Subjects
TRM ,Seismic behaviour ,Seismic retrofit ,Energy dissipation ,Enginyeria civil::Materials i estructures [Àrees temàtiques de la UPC] ,Building and Construction ,FRCM ,Damping ,Estructures de murs ,General Materials Science ,SRG ,Masonry ,Shear wall ,Civil and Structural Engineering ,Ductility - Abstract
Recent research on the mechanical characterisation of Steel Reinforced Grout (SRG) has highlighted its excellent performance as strengthening solutions for masonry structures. Using SRG with limited fabric density ensures a good textile-matrix interlocking, preventing at the same time the failure due to slippage or debonding from the substrate. This paper presents an experimental investigation on the use of SRG as in-plane strengthening solution for shear masonry walls composed of handmade solid clay brick and hydraulic lime mortar. Cyclic shear compression tests were carried out on walls strengthened with SRG comprising low density steel sheets (LDS). The SRG was applied on both faces of the walls with a strip configuration, using one and two layers of LDS. The experimental programme aimed to study the influence of the number of textile layers on the in-plane response of strengthened masonry walls in terms of failure mechanism, load-bearing capacity, energy dissipation, and ductility. The authors gratefully acknowledge the financial support from the Ministry of Economy and Competitiveness, Spain and from the Ministry of Science, Innovation and Universities of the Spanish Government, as well as that of the ERDF (European Regional Development Fund) through the project SEVERUS (Multilevel evaluation of seismic vulnerability and risk mitigation of masonry buildings in resilient historical urban centres, Ref. num. RTI2018-099589-B-I00). The reinforcement systems and construction of the specimens for the experimental programme have been funded by Kerakoll Spa through the RTD project “Seismic Strengthening of Masonry Walls” (Ref. num. A-01278). The authors wish to thank Paolo Casadei, José Luis Sanchez and José Dobón from Kerakoll Spa for their involvement and support. The support from Secretaria d’Universitats i Investigació de la Generalitat de Catalunya, Spain through a predoctoral grant awarded to the first author is also gratefully acknowledged. Peer Reviewed Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura::9.1 - Desenvolupar infraestructures fiables, sostenibles, resilients i de qualitat, incloent infraestructures regionals i transfrontereres, per tal de donar suport al desenvolupament econòmic i al benestar humà, amb especial atenció a l’accés assequible i equitatiu per a totes les persones Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.4 - Redoblar els esforços per a protegir i salvaguardar el patrimoni cultural i natural del món Objectius de Desenvolupament Sostenible::13 - Acció per al Clima Objectius de Desenvolupament Sostenible::13 - Acció per al Clima::13.1 - Enfortir la resiliència i la capacitat d’adaptació als riscos relacionats amb el clima i els desastres naturals a tots els països
- Published
- 2022
- Full Text
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38. Wafer-scale pulsed laser deposition of ITO for solar cells: reduced damage vs. interfacial resistance
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Yury Smirnov, Pierre-Alexis Repecaud, Leonard Tutsch, Ileana Florea, Kassio P.S. Zanoni, Abhyuday Paliwal, Henk J. Bolink, Pere Roca i Cabarrocas, Martin Bivour, Monica Morales-Masis, Publica, MESA+ Institute, and Inorganic Materials Science
- Subjects
integumentary system ,Chemistry (miscellaneous) ,General Materials Science ,digestive system ,Materials ,Cèl·lules fotoelèctriques - Abstract
Transparent conducting oxides (TCOs) used in solar cells must be optimized to achieve minimum parasitic absorption losses while providing sufficient lateral conductivity. Low contact resistance with the adjacent device layers and low damage to the substrate during deposition of the TCO are also important requirements to ensure high solar cell efficiencies. Pulsed laser deposition (PLD) has been proposed as an alternative low-damage TCO deposition technique on top of sensitive layers and interfaces in organic and perovskite solar cells but is yet to be studied for the more mature silicon technology. Focusing on the PLD deposition pressure as the key parameter to reduce damage, we developed tin-doped indium oxide (ITO) with a sheet resistance of 60 ω □-1 at different pressures and implemented it in silicon heterojunction (SHJ) solar cells. Buffer-free semi-transparent perovskite cells with the same PLD ITO electrodes were also fabricated for comparison. While in the perovskite cells increased ITO deposition pressure leads to an improved open circuit voltage and fill factor indicative of damage reduction, SHJ cells with PLD ITO at all conditions maintained a high passivation quality, but increased pressures lead to high series resistance. Transmission electron microscopy and time-of-flight secondary ion mass spectrometry confirmed the formation of a parasitic SiOx at the ITO/a-Si:H interface of the SHJ cell causing a transport barrier. The optimized ITO films with the highest carrier density were able to obtain >21% SHJ efficiency with 75 nm-thick PLD ITO. Moreover, reducing the ITO thickness to ∼45 nm and using TiOx for optical compensation enables fabrication of SHJ devices with reduced indium consumption and efficiencies of >22%. This journal is
- Published
- 2022
39. Cyclic shear-compression testing of brick masonry walls repaired and retrofitted with basalt textile reinforced mortar
- Author
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Larisa Garcia-Ramonda, Luca Pelà, Pere Roca, Guido Camata, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials
- Subjects
Fibre Reinforced Cementitious Matrix (FRCM) ,Cyclic shear compression test ,Estructures de murs ,Ceramics and Composites ,Enginyeria civil::Materials i estructures [Àrees temàtiques de la UPC] ,Masonry ,Seismic Strengthening ,Textile Reinforced Mortar (TRM) ,Civil and Structural Engineering ,Ductility - Abstract
This paper reports an experimental programme on masonry walls composed of handmade solid clay brick and hydraulic lime mortar. Reversed cyclic shear compression tests were carried out on the walls in three different configurations: unreinforced, repaired and retrofitted, and just retrofitted. Damaged walls were repaired and retrofitted with Basalt Textile Reinforced Mortar (B TRM) and tested again to investigate the recovery of strength, stiffness and the improvement in drift capacity. The repair consisted in filling the open cracks and replacing the damaged bricks by following the so-called ‘‘scuci-cuci’’ technique. The just retrofitted configuration consisted of externally bonded B-TRM on undamaged walls. The B-TRM system comprised continuous bidirectional grids of basalt fibre embedded in hydraulic lime mortar on both surfaces of the walls. The experimental results showed the suitability of the proposed solutions for seismic retrofit and post-earthquake repair of existing masonry buildings. The research results highlighted the capacity of the proposed repair technique to reinforce damaged walls and the effectiveness of the investigated B-TRM system in increasing the resistance, the ductility, and the energy dissipation of unreinforced clay brick masonry. In addition, the results allowed a better understanding of the behaviour of masonry walls subjected to cyclic horizontal displacement in terms of failure mechanism and displacement capacities. The authors gratefully acknowledge the financial support from the Ministry of Economy and Competitiveness and from the Ministry of Science, Innovation and Universities of the Spanish Government, as well as that of the ERDF (European Regional Development Fund) through the project SEVERUS (Multilevel evaluation of seismic vulnerability and risk mitigation of masonry buildings in resilient historical urban centres, Ref. num. RTI2018-099589-B-I00). The reinforcement systems and construction of the specimens for the experimental programme have been funded by Kerakoll Spa through the RTD project “Seismic Strengthening of Masonry Walls” (Ref. num. A-01278). The authors wish to thank Paolo Casadei, José Luis Sanchez and José Dobón from Kerakoll Spa for their involvement and support. The support from Secretaria d’Universitats i Investigació de la Generalitat de Catalunya through a predoctoral grant awarded to the first author is also gratefully acknowledged. Peer Reviewed Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura::9.1 - Desenvolupar infraestructures fiables, sostenibles, resilients i de qualitat, incloent infraestructures regionals i transfrontereres, per tal de donar suport al desenvolupament econòmic i al benestar humà, amb especial atenció a l’accés assequible i equitatiu per a totes les persones Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.4 - Redoblar els esforços per a protegir i salvaguardar el patrimoni cultural i natural del món Objectius de Desenvolupament Sostenible::13 - Acció per al Clima Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura Objectius de Desenvolupament Sostenible::13 - Acció per al Clima::13.1 - Enfortir la resiliència i la capacitat d’adaptació als riscos relacionats amb el clima i els desastres naturals a tots els països
- Published
- 2022
- Full Text
- View/download PDF
40. Dynamic investigation of cultural heritage buildings for seismic safety asssessment
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Ahmed Elyamani, Pere Roca, Oriol Caselles, Jaime Clapes, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials, and Universitat Politècnica de Catalunya. GIES - Geofísica i Enginyeria Sísmica
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Cultural heritage structures ,Edificis històrics -- Efecte dels terratrèmols ,Model updating ,Dynamic identification ,Arquitectura [Àrees temàtiques de la UPC] ,Seismic assessment ,Historic buildings -- Earthquake effects ,Enginyeria civil::Geotècnia::Sismologia [Àrees temàtiques de la UPC] ,Dynamic monitoring ,Numerical model - Abstract
Cultural heritage buildings are prone to failures when subjected to seismic events, and recent earthquakes worldwide resulted in many losses of these buildings. Therefore, there is a need for methodologies for assessing their seismic safety that should be based on enough knowledge of the building. Here, dynamic investigation by dynamic identification testing and dynamic monitoring increase significantly the level of knowledge about the assessed building. The dynamic identification tests give global information about the dynamic properties like natural frequencies that are useful in calibrating and updating a numerical model of the building that could be used in the seismic safety evaluation. Dynamic monitoring gives the dynamic properties’ evolution in time and may be used as an early warning tool able to send alarms when meaningful changes in dynamic properties are observed. This chapter gives some considerations on the different investigation activities of dynamic identification, dynamic monitoring, numerical model updating, and seismic safety assessment of cultural heritage buildings. As an application, the case study of the historic Mallorca cathedral is discussed. This study has been carried out within the context of the project “New Integrated Knowledge-based Approaches to the Protection of Cultural Heritage from Earthquake-Induced Risk-NIKER” sponsored by the European Commission (Grant Agreement No. 244123), which is gratefully acknowledged.
- Published
- 2022
41. Experimental response of a scaled dry-joint masonry arch subject to inclined support displacements
- Author
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Chiara Ferrero, Chiara Calderini, Pere Roca, Universitat Politècnica de Catalunya. Doctorat en Enginyeria de la Construcció, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials
- Subjects
Dry-joint masonry arches ,Experimental tests ,Inclined support displacements ,Settlements ,Murs ,Enginyeria civil::Materials i estructures [Àrees temàtiques de la UPC] ,Masonry ,Civil and Structural Engineering - Abstract
Support displacements are a major cause of damage to masonry arches. In the last decades, the effect of large support displacements on the stability of masonry arches has been widely investigated. However, there is still a lack of studies dealing with inclined support displacements. In this work, a large experimental campaign was performed on a 1:10 small-scale segmental masonry arch subjected to several combinations of vertical and horizontal support displacements. The mockup was built as a dry-joint assemblage of blocks and was tested to collapse by using a testing machine designed ad hoc. The effects of the displacement direction on the arch static behaviour were evaluated in terms of evolution of the hinge configuration, collapse mechanism, support reaction-displacement curves, ultimate displacement capacity and support reactions at collapse. In light of the experimental results, new conclusions about the arch response to inclined support displacements were drawn. A limit displacement domain, computed as a function of the direction of the imposed support displacements, was also proposed. The financial support of PRIN 2015 Program by the Italian Ministry of Education, University and Research (MIUR) is gratefully acknowledged for funding the research project “Protecting the Cultural Heritage from water-soil interaction related threats” (Prot. No. 2015EAM9S5), which is the main framework of the study presented in this article.
- Published
- 2022
- Full Text
- View/download PDF
42. A three-dimensional approach to the Extended Limit Analysis of Reinforced Masonry
- Author
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Philippe Block, Tom Van Mele, Andrew Liew, Pere Roca, David López López, Tomás Méndez Echenagucia, Universitat Politècnica de Catalunya. Departament de Tecnologia de l'Arquitectura, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya. REARQ - Rehabilitació i Restauració Arquitectònica, and Universitat Politècnica de Catalunya. ATEM - Anàlisi i Tecnologia d'Estructures i Materials
- Subjects
Speedup ,Process (engineering) ,Computer science ,Stability (learning theory) ,Reinforced brick ,020101 civil engineering ,02 engineering and technology ,Bending ,Thrust Network Analysis ,Edificació::Elements constructius d'edificis [Àrees temàtiques de la UPC] ,0201 civil engineering ,Tile vault ,Masonry ,Formwork ,Concrete shells ,Limit analysis ,Thrust network analysis ,Extended limit analysis of reinforced masonry ,Architecture ,0202 electrical engineering, electronic engineering, information engineering ,Vaults (Architecture) ,Extended Limit Analysis of Reinforced Masonry ,Safety, Risk, Reliability and Quality ,Civil and Structural Engineering ,Infografia tridimensional ,business.industry ,020207 software engineering ,Building and Construction ,Structural engineering ,visual_art ,Voltes (Arquitectura) ,visual_art.visual_art_medium ,Tile ,Three-dimensional modeling ,business - Abstract
The Extended Limit Analysis of Reinforced Masonry (ELARM) is a simple and user-friendly method for the design and structural analysis of singly-curved, reinforced tile vaults [1]. It is based on limit analysis but takes into account the reinforcement’s contribution to the composite cross-section’s bending capacity. A three-dimensional approach to ELARM is presented in this paper. The theoretical framework to understand the implications and limitations of extending ELARM to fully 3D structures is described, together with the strategies to carry out the leap from 2D to 3D. This extension is a lower-bound approach for the design of reinforced masonry, reinforced concrete and concrete-masonry composite shells and the assessment of their strength and stability against external loading. The new, extended method is implemented computationally to speed up the iterative processes, provide quick structural feedback, offer immediate results and allow for user-interactive form-finding and optimisation procedures. Different applications of the developed tool are described through the presentation of examples, including reinforcement optimisation, a form-finding process and a case with a shape beyond funicular geometry. [1] D. López López, P. Roca, A. Liew, T. Van Mele, P. Block Tile vaults as integrated formwork for reinforced concrete: Construction, experimental testing and a method for the design and analysis of two-dimensional structures Eng Struct, 188 (2019), pp. 233-248, 10.1016/j.engstruct.2019.03.034, Structures, 35, ISSN:2352-0124
- Published
- 2022
- Full Text
- View/download PDF
43. Effect of joint deformability on the experimental and numerical response of dry-joint masonry arches subjected to large support displacements
- Author
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Chiara Ferrero, Chiara Calderini, and Pere Roca
- Subjects
Civil and Structural Engineering - Published
- 2023
44. In situ minority carrier lifetime via fast modulated photoluminescence
- Author
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Mateusz Poplawski, François Silva, Jean-Charles Vanel, and Pere Roca i Cabarrocas
- Subjects
Renewable Energy, Sustainability and the Environment ,Electrical and Electronic Engineering ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Abstract
Modulated photoluminescence (MPL) is a powerful technique for determining the effective minority carrier lifetime (τeff) of semiconductor materials and devices. MPL is based on the measurement of phase shifts between two sinusoidal waves (minimal amplitude excitation; and PL signal). In particular, in situ τeff has been proven to be an effective measurement at showing changes within a plasma-enhanced chemical vapor deposition reactor during fabrication of c-Si solar cells. However, the required time for a single measurement, using the previous method, was 40 s. In this paper a new input signal is proposed, called Dolphin's Wave, providing a method for decreasing the required measurement period to under 2 s, using superposition, frequency sweeps, and wavelets.
- Published
- 2023
45. Low-Temperature Plasma-Assisted Growth of Core–Shell GeSn Nanowires with 30% Sn
- Author
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Sébastien Duguay, Simona Moldovan, Pere Roca i Cabarrocas, Philippe Pareige, Wanghua Chen, Edy Azrak, Groupe de physique des matériaux (GPM), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique des interfaces et des couches minces [Palaiseau] (LPICM), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Ningbo University (NBU), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), and Normandie Université (NU)
- Subjects
Materials science ,Alloy ,Analytical chemistry ,Nanowire ,02 engineering and technology ,Substrate (electronics) ,engineering.material ,010402 general chemistry ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,Physical and Theoretical Chemistry ,ComputingMilieux_MISCELLANEOUS ,Eutectic system ,Low temperature plasma ,Plasma ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,General Energy ,chemistry ,Germane ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,engineering ,[PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph] ,0210 nano-technology - Abstract
We report on the growth of Sn-catalyzed GeSn nanowires (NWs) having a GeSn core and a c-Ge shell in the presence of germane plasma at substrate temperatures (TS) below the GeSn eutectic temperature (TE), containing an exceptional Sn concentration of 30 at. % in their core. The differences between the NWs produced at TS above and below TE of the GeSn alloy are highlighted. Two types of NW growth process are identified: the previously reported in-plane solid–liquid–solid (IPSLS) process for TS ≥ TE and a plasma-assisted IPSLS (PA-IPSLS) method taking place at TS < TE; the crucial role of plasma in providing the energy necessary to melt the Sn catalyst at substrate temperatures lower than TE is discussed. The thermal activation window for each method is determined. The PA-IPSLS process is shown to provide an efficient strategy for the growth of crystalline GeSn NWs with a high Sn incorporation in a growth duration of less than 3 min.
- Published
- 2019
46. Local V OC Measurements by Kelvin Probe Force Microscopy Applied on P-I-N Radial Junction Si Nanowires
- Author
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Letian Dai, José Alvarez, Pere Roca i Cabarrocas, Sylvain Le Gall, Jean-Paul Kleider, Clément Marchat, Soumyadeep Misra, Laboratoire Génie électrique et électronique de Paris (GeePs), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Photovoltaïque d’Ile-de-France (ITE) (IPVF), Laboratoire de physique des interfaces et des couches minces [Palaiseau] (LPICM), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique de la matière condensée (LPMC), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), and ANR-14-CE05-0025,SOLARIUM,Cellules Solaires à jonction radiale à base de nanofils de Silicium avec une technologie couche mince(2014)
- Subjects
Solar cells ,Materials science ,Surface photovoltage ,Characterization ,Nanowire ,Nanochemistry ,SPS ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,[SPI.MAT]Engineering Sciences [physics]/Materials ,Surface photovoltage spectroscopy ,Microscopy ,lcsh:TA401-492 ,General Materials Science ,[SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics ,Nanoscopic scale ,Kelvin probe force microscope ,business.industry ,Open-circuit voltage ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,KP ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Band bending ,Nanoscale ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic ,Optoelectronics ,lcsh:Materials of engineering and construction. Mechanics of materials ,0210 nano-technology ,business - Abstract
International audience; This work focuses on the extraction of the open circuit voltage (VOC) on photovoltaic nanowires by surface photovoltage (SPV) based on Kelvin probe force microscopy (KPFM) measurements. In a first approach, P-I-N radial junction (RJ) silicon nanowire (SiNW) devices were investigated under illumination by KPFM and current-voltage (I-V) analysis. Within 5%, the extracted SPV correlates well with the VOC. In a second approach, local SPV measurements were applied on single isolated radial junction SiNWs pointing out shadowing effects from the AFM tip that can strongly impact the SPV assessment. Several strategies in terms of AFM tip shape and illumination orientation have been put in place to minimize this effect. Local SPV measurements on isolated radial junction SiNWs increase logarithmically with the illumination power and demonstrate a linear behavior with the VOC. The results show notably that contactless measurements of the VOC become feasible at the scale of single photovoltaic SiNW devices.
- Published
- 2019
47. Tapering-free monocrystalline Ge nanowires synthesized via plasma-assisted VLS using In and Sn catalysts
- Author
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Jian Tang, Jun Wang, Jean-Luc Maurice, Wanghua Chen, Martin Foldyna, Linwei Yu, Egor D Leshchenko, Vladimir G Dubrovskii, and Pere Roca I Cabarrocas
- Subjects
Mechanics of Materials ,Mechanical Engineering ,General Materials Science ,Bioengineering ,General Chemistry ,Electrical and Electronic Engineering - Abstract
In and Sn are the type of catalysts which do not introduce deep level electrical defects within the bandgap of germanium (Ge). However, Ge nanowires produced using these catalysts usually have a large diameter, a tapered morphology, and mixed crystalline and amorphous phases. In this study, we show that plasma-assisted vapor–liquid–solid (PA-VLS) method can be used to synthesize Ge nanowires. Moreover, at certain parameter domains, the sidewall deposition issues of this synthesis method can be avoided and long, thin tapering-free monocrystalline Ge nanowires can be obtained with In and Sn catalysts. We find two quite different parameter domains where Ge nanowire growth can occur via PA-VLS using In and Sn catalysts: (i) a low temperature-low pressure domain, below ∼235 °C at a GeH4 partial pressure of ∼6 mTorr, where supersaturation in the catalyst occurs thanks to the low solubility of Ge in the catalysts, and (ii) a high temperature-high pressure domain, at ∼400 °C and a GeH4 partial pressure above ∼20 mTorr, where supersaturation occurs thanks to the high GeH4 concentration. While growth at 235 °C results in tapered short wires, operating at 400 °C enables cylindrical nanowire growth. With the increase of growth temperature, the crystalline structure of the nanowires changes from multi-crystalline to mono-crystalline and their growth rate increases from ∼0.3 nm s−1 to 5 nm s−1. The cylindrical Ge nanowires grown at 400°C usually have a length of few microns and a radius of around 10 nm, which is well below the Bohr exciton radius in bulk Ge (24.3 nm). To explain the growth mechanism, a detailed growth model based on the key chemical reactions is provided.
- Published
- 2021
48. Competition for endothelial cell polarity drives vascular morphogenesis
- Author
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Daniela Ramalho, I. Mauldin, I. Fortunato, L. H. Misikova, D. Barata, M. Dominguez-Cejudo, Miguel O. Bernabeu, Yulia Carvalho, Anna Pezzarossa, Catarina G Fonseca, Andreia Pena, Anne Eichmann, Pere Roca-Cusachs, Ylenia Giarratano, L. M. Faure, Xavier Trepat, Claudio A. Franco, M. Ouarne, Manuel Gomez-Gonzalez, Georgia Zarkada, and Pedro Miguel Branco Barbacena
- Subjects
Sprouting angiogenesis ,History ,Polymers and Plastics ,Chemistry ,Polarity (physics) ,Industrial and Manufacturing Engineering ,Cell biology ,Adherens junction ,Endothelial stem cell ,Focal adhesion ,Vascular endothelial growth factor A ,medicine.anatomical_structure ,Cell polarity ,medicine ,Business and International Management ,Blood vessel - Abstract
Blood vessel formation generates unique vascular patterns in each individual. The principles governing the apparent stochasticity of this process remain to be elucidated. Using mathematical methods, we find that the transition between two fundamental vascular morphogenetic programs – sprouting angiogenesis and vascular remodeling – is established by a shift on collective front-rear polarity of endothelial cells. We demonstrate that the competition between biochemical (VEGFA) and mechanical (blood flow-induced shear stress) cues controls this collective polarity shift. Shear stress increases tension at focal adhesions overriding VEGFA-driven collective polarization, which relies on tension at adherens junctions. We propose that vascular morphogenetic cues compete to regulate individual cell polarity and migration through tension shifts that translates into tissue-level emergent behaviors, ultimately leading to uniquely organized vascular patterns.
- Published
- 2021
49. Comparative Study on the Quality of Microcrystalline and Epitaxial Silicon Films Produced by PECVD Using Identical SiF4 Based Process Conditions
- Author
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Mario Moreno, Javier Flores, Alfonso Torres, Arturo Ponce, Hector Vazquez-Leal, Alfredo Morales, Gilles Patriarche, Luis A. Hernández, Pere Roca i Cabarrocas, Arturo Galindo, Eduardo Ortega, Roberto Ambrosio, Laboratoire de physique des interfaces et des couches minces [Palaiseau] (LPICM), and École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Technology ,Materials science ,microcrystalline silicon ,02 engineering and technology ,Epitaxy ,01 natural sciences ,symbols.namesake ,Ellipsometry ,Plasma-enhanced chemical vapor deposition ,0103 physical sciences ,General Materials Science ,Crystalline silicon ,[INFO.INFO-BT]Computer Science [cs]/Biotechnology ,High-resolution transmission electron microscopy ,ComputingMilieux_MISCELLANEOUS ,010302 applied physics ,Microscopy ,QC120-168.85 ,electron microscopy ,epitaxial growth ,QH201-278.5 ,plasma enhanced chemical vapor deposition ,021001 nanoscience & nanotechnology ,Engineering (General). Civil engineering (General) ,TK1-9971 ,Microcrystalline ,Chemical engineering ,Descriptive and experimental mechanics ,Thin-film transistor ,symbols ,Electrical engineering. Electronics. Nuclear engineering ,TA1-2040 ,0210 nano-technology ,Raman spectroscopy - Abstract
Hydrogenated microcrystalline silicon (µc-Si:H) and epitaxial silicon (epi-Si) films have been produced from SiF4, H2 and Ar mixtures by plasma enhanced chemical vapor deposition (PECVD) at 200 °C. Here, both films were produced using identical deposition conditions, to determine if the conditions for producing µc-Si with the largest crystalline fraction (XC), will also result in epi-Si films that encompass the best quality and largest crystalline silicon (c-Si) fraction. Both characteristics are of importance for the development of thin film transistors (TFTs), thin film solar cells and novel 3D devices since epi-Si films can be grown or etched in a selective manner. Therefore, we have distinguished that the H2/SiF4 ratio affects the XC of µc-Si, the c-Si fraction in epi-Si films, and the structure of the epi-Si/c-Si interface. Raman and UV-Vis ellipsometry were used to evaluate the crystalline volume fraction (Xc) and composition of the deposited layers, while the structure of the films were inspected by high resolution transmission electron microscopy (HRTEM). Notably, the conditions for producing µc-Si with the largest XC are different in comparison to the fabrication conditions of epi-Si films with the best quality and largest c-Si fraction.
- Published
- 2021
50. Ruffled in water, smooth in honey
- Author
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Laura M. Faure and Pere Roca-Cusachs
- Subjects
General Physics and Astronomy - Published
- 2022
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