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Wu L, Pasini D. Zero modes activation to reconcile floppiness, rigidity, and multistability into an all-in-one class of reprogrammable metamaterials. Nat Commun 2024; 15:3087. [PMID: 38600069 PMCID: PMC11006655 DOI: 10.1038/s41467-024-47180-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/15/2024] [Indexed: 04/12/2024] Open
Abstract
Existing mechanical metamaterials are typically designed to either withstand loads as a stiff structure, shape morph as a floppy mechanism, or trap energy as a multistable matter, distinct behaviours that correspond to three primary classes of macroscopic solids. Their stiffness and stability are sealed permanently into their architecture, mostly remaining immutable post-fabrication due to the invariance of zero modes. Here, we introduce an all-in-one reprogrammable class of Kagome metamaterials that enable the in-situ reprogramming of zero modes to access the apparently conflicting properties of all classes. Through the selective activation of metahinges via self-contact, their architecture can be switched to acquire on-demand rigidity, floppiness, or global multistability, bridging the seemingly uncrossable gap between structures, mechanisms, and multistable matters. We showcase the versatile generalizations of the metahinge and remarkable reprogrammability of zero modes for a range of properties including stiffness, mechanical signal guiding, buckling modes, phonon spectra, and auxeticity, opening a plethora of opportunities for all-in-one materials and devices.
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Affiliation(s)
- Lei Wu
- Department of Mechanical Engineering, McGill University, Montreal, Canada
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, Montreal, Canada.
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2
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Xie Z, Lu Q, Guo J, Lin W, Ge G, Tang Y, Pasini D, Wang W. Semantic segmentation for tooth cracks using improved DeepLabv3+ model. Heliyon 2024; 10:e25892. [PMID: 38380020 PMCID: PMC10877285 DOI: 10.1016/j.heliyon.2024.e25892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 02/01/2024] [Accepted: 02/05/2024] [Indexed: 02/22/2024] Open
Abstract
Objective Accurate and prompt detection of cracked teeth plays a critical role for human oral health. The aim of this paper is to evaluate the performance of a tooth crack segmentation model (namely, FDB-DeepLabv3+) on optical microscopic images. Method The FDB-DeepLabv3+ model proposed here improves feature learning by replacing the backbone with ResNet50. Feature pyramid network (FPN) is introduced to fuse muti-level features. Densely linked atrous spatial pyramid pooling (Dense ASPP) is applied to achieve denser pixel sampling and wider receptive field. Bottleneck attention module (BAM) is embedded to enhance local feature extraction. Results Through testing on a self-made hidden cracked tooth dataset, the proposed method outperforms four classical networks (FCN, U-Net, SegNet, DeepLabv3+) on segmentation results in terms of mean pixel accuracy (MPA) and mean intersection over union (MIoU). The network achieves an increase of 11.41% in MPA and 12.14% in MIoU compared to DeepLabv3+. Ablation experiments shows that all the modifications are beneficial. Conclusion An improved network is designed for segmenting tooth surface cracks with good overall performance and robustness, which may hold significant potential in computer-aided diagnosis of cracked teeth.
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Affiliation(s)
- Zewen Xie
- School of Mechanical and Electrical Engineering, Guangzhou University, Guangzhou, 510006, China
- School of Physics and Material Science, Guangzhou University, Guangzhou, 510006, China
| | - Qilin Lu
- School of Mechanical and Electrical Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Juncheng Guo
- School of Mechanical and Electrical Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Weiren Lin
- School of Mechanical and Electrical Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Guanghua Ge
- Department of Dentistry, Hospital of Guangdong University of Technology, Guangdong University of Technology, Guangzhou, 510006, China
| | - Yadong Tang
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, QC H3A 0C3, Canada
| | - Wenlong Wang
- School of Mechanical and Electrical Engineering, Guangzhou University, Guangzhou, 510006, China
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, QC H3A 0C3, Canada
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3
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Qiao C, Agnelli F, Pokkalla DK, D'Ambrosio N, Pasini D. Anisotropic Morphing in Bistable Kirigami through Symmetry Breaking and Geometric Frustration. Adv Mater 2024:e2313198. [PMID: 38413013 DOI: 10.1002/adma.202313198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/24/2024] [Indexed: 02/29/2024]
Abstract
Shape morphing in bistable kirigami enables remarkable functionalities appealing to a diverse range of applications across the spectrum of length scale. At the core of their shape shifting lies the architecture of their repeating unit, where highly deformable slits and quasi-rigid rotating units often exhibit multiple symmetries that confer isotropic deployment obeying uniform scaling transformation. In this work, symmetry breaking in bistable kirigami is investigated to access geometric frustration and anisotropic morphing, enabling arbitrarily scaled deployment in planar and spatial bistable domains. With an analysis on their symmetry properties complemented by a systematic investigation integrating semi-analytical derivations, numerical simulations, and experiments on elastic kirigami sheets, this work unveils the fundamental relations between slit symmetry, geometric frustration, and anisotropic bistable deployment. Furthermore, asymmetric kirigami units are leveraged in planar and flat-to-3D demonstrations to showcase the pivotal role of shear deformation in achieving target shapes and functions so far unattainable with uniformly stretchable kirigami. The insights provided in this work unveil the role of slit symmetry breaking in controlling the anisotropic bistable deployment of soft kirigami metamaterials, enriching the range of achievable functionalities for applications spanning deployable space structures, wearable technologies, and soft machines.
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Affiliation(s)
- Chuan Qiao
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
- Department of Mechanical Engineering, McGill University, Montréal, Québec, H3A 0C3, Canada
| | - Filippo Agnelli
- Department of Mechanical Engineering, McGill University, Montréal, Québec, H3A 0C3, Canada
| | - Deepak Kumar Pokkalla
- Department of Mechanical Engineering, McGill University, Montréal, Québec, H3A 0C3, Canada
| | - Nicholas D'Ambrosio
- Department of Mechanical Engineering, McGill University, Montréal, Québec, H3A 0C3, Canada
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, Montréal, Québec, H3A 0C3, Canada
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4
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El Elmi A, Pasini D. Tunable sequential pathways through spatial partitioning and frustration tuning in soft metamaterials. Soft Matter 2024; 20:1186-1198. [PMID: 38197440 DOI: 10.1039/d3sm01174g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Elastic instabilities have been leveraged in soft metamaterials to attain novel functionalities such as mechanical memory and sequential pathways. Pathways have been realized in complex media or within a collection of hysteretic elements. However, much less has been explored in frustrated and partitioned soft metamaterials. In this work, we introduce spatial partitioning as a method to localize deformation in sub-regions of a large and soft metamaterial. The partitioning is achieved through the strategic arrangement of soft inclusions in a soft lattice, which form distinct regions behaving as mechanical units. We examine two partitions: an equally spaced layer partition with mechanical units connected in series, and a cross partition, represented by interconnected series of mechanical units in parallel. Sequential pathways are obtained by frustrating the partitioned metamaterial post-manufacture and are characterized by tracking the polarization change in each partition region. Through a combination of experiments and simulations, we demonstrate that partitioning enables tuning the pathway from longitudinal with weak interactions to a pathway exhibiting strong interactions rising from geometric incompatibility and central domain rotation. We show that tuning the level of uniform lateral pre-strain provides a wide range of tunability from disabling to modifying the sequential pathway. We also show that imposing a nonuniform confinement and altering the tilting of one or two of the domain edges enables to program the pathway, access a larger set of states, and tune the level of interaction between the regions.
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Affiliation(s)
- Asma El Elmi
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke St. West, H3A 0C3 Montréal, Québec, Canada.
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke St. West, H3A 0C3 Montréal, Québec, Canada.
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5
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Wu L, Pasini D. In Situ Activation of Snap-Through Instability in Multi-Response Metamaterials through Multistable Topological Transformation. Adv Mater 2023; 35:e2301109. [PMID: 37246407 DOI: 10.1002/adma.202301109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 04/17/2023] [Indexed: 05/30/2023]
Abstract
Snap-through instability has been widely leveraged in metamaterials to attain non-monotonic responses for a specific subset of applications where conventional monotonic materials fail to perform. In the remaining more plentiful set of ordinary applications, snap-through instability is harmful, and current snapping metamaterials become inadequate because their capacity to snap cannot be suppressed post-fabrication. Here, a class of topology-transformable metamaterials is introduced to enable in situ activation and deactivation of the snapping capacity, providing a remarkable level of versatility in switching between responses from monotonic to monostable and bistable snap-through. Theoretical analysis, numerical simulations, and experiments are combined to unveil the role played by contact in the topological transformation capable of increasing the geometry incompatibility and confinement stiffness of selected architectural members. The strategy here presented for post-fabrication reprogrammability of matter and on-the-fly response switching paves the way to multifunctionality for application in multiple sectors from mechanical logic gates, and adjustable energy dissipators, to in situ adaptable sport equipment.
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Affiliation(s)
- Lei Wu
- Department of Mechanical Engineering, McGill University, Montreal, Quebec H3A 0C3, Canada
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, Montreal, Quebec H3A 0C3, Canada
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6
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Roletto A, Catania D, Ciaralli C, Cozzi A, Di Feo D, Durante S, Pasini D, Raiano N, Zanardo M. National survey for investigating the diagnostic imaging departments reorganization and management during the COVID-19 pandemic. J Med Imaging Radiat Sci 2022. [PMCID: PMC9716005 DOI: 10.1016/j.jmir.2022.10.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Introduction The COVID-19 pandemic has had a profound impact on radiography services globally. The objective of this study was to evaluate the impact of the COVID-19 pandemic on the management of radiology departments in Italy. Methods An online survey with 32 questions was developed and promoted by the Italian Federation of Scientific Radiographer Societies (FASTeR) and sent to all Radiology Service Managers (RSM) identified in the RSM committee of the Italian Federation of Radiographers and Health Professionals, counting for 39 Italian RSM, representing more than 1,200 radiographers. The survey included questions regarding RSM demographics data, the number of radiographers and specialties managed, the effects of the pandemic on the diagnostic imaging service, and any reorganizations that had been implemented, such as the partial or total suspension of diagnostic activities and the number of radiographers tested as positive to COVID-19. Results Twenty (52%) RSM from different Italian regions completed the questionnaire. A total of 70% of respondents had implemented reorganizations in terms of space, equipment, and pathways dedicated to COVID-19-infected patients, including an extension of the timing of acquisition of the exams. More than half of the respondents reported breast and DXA imaging unit had suffered the most suspension of activities. 70% of respondents reported that more than 50% of radiographers were resulted as COVID-19 positive. Conclusion These data show how challenging was of the reorganization of Italian diagnostic imaging departments during the COVID-19 pandemic, with impact on the suspension of some exams and the rescheduling of breast and DXA imaging. The reorganization of the services also had to consider the high number of radiographers suspended from activity due to the positivity to COVID-19, and the lengthening of the duration of the examinations due to the sanitation of the spaces.
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Affiliation(s)
- Andrea Roletto
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - D Catania
- Directorate General for Healthcare Professions, San Raffaele Research Hospital, Milan, Italy
| | - C Ciaralli
- Radiology department, Lazzaro Spallanzani National Institute for Infectious Diseases, Rome, Italy
| | - A Cozzi
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - D Di Feo
- Radiology Department, Meyer Children's Hospital, Florence, Italy
| | - S Durante
- Directorate of the Nursing, Technical and Rehabilitation Assistance Service, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - D Pasini
- Directorate General for Healthcare Professions, Agostino Gemelli University Policlinic, Rome, Italy
| | - N Raiano
- Radiology and Radiotherapy Department, Research Cancer Center “Pascale Foundation”, Naples, Italy
| | - M Zanardo
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
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7
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Davino S, Callegari D, Pasini D, Thomas M, Nicotera I, Bonizzoni S, Mustarelli P, Quartarone E. Cross-Linked Gel Electrolytes with Self-Healing Functionalities for Smart Lithium Batteries. ACS Appl Mater Interfaces 2022; 14:51941-51953. [PMID: 36355595 PMCID: PMC9706498 DOI: 10.1021/acsami.2c15011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/31/2022] [Indexed: 06/01/2023]
Abstract
Next-generation Li-ion batteries must guarantee improved durability, quality, reliability, and safety to satisfy the stringent technical requirements of crucial sectors such as e-mobility. One breakthrough strategy to overcome the degradation phenomena affecting the battery performance is the development of advanced materials integrating smart functionalities, such as self-healing units. Herein, we propose a gel electrolyte based on a uniform and highly cross-linked network, hosting a high amount of liquid electrolyte, with multiple advantages: (i) autonomous, fast self-healing, and a promising PF5-scavenging role; (ii) solid-like mechanical stability despite the large fraction of entrapped liquid; and (iii) good Li+ transport. It is shown that such a gel electrolyte has very good conductivity (>1.0 mS cm-1 at 40 °C) with low activation energy (0.25 eV) for the ion transport. The transport properties are easily restored in the case of physical damages, thanks to the outstanding capability of the polymer to intrinsically repair severe cracks or fractures. The good elastic modulus of the cross-linked network, combined with the high fraction of anions immobilized within the polymer backbone, guarantees stable Li electrodeposition, disfavoring the formation of mossy dendrites with the Li metal anode. We demonstrate the electrolyte performance in a full-cell configuration with a LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode, obtaining good cycling performance and stability.
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Affiliation(s)
- S. Davino
- Department
of Chemistry, University of Pavia, Via Taramelli 16, Pavia27100, Italy
| | - D. Callegari
- Department
of Chemistry, University of Pavia, Via Taramelli 16, Pavia27100, Italy
- GISEL—Centro
di Riferimento Nazionale per i Sistemi di Accumulo Elettrochimico
di Energia, INSTM, via G. Giusti 9, Firenze50121, Italy
| | - D. Pasini
- Department
of Chemistry, University of Pavia, Via Taramelli 16, Pavia27100, Italy
| | - M. Thomas
- Department
of Chemistry and Chemical Technology, University
of Calabria, Via P. Bucci, Rende, Cosenza87036, Italy
| | - I. Nicotera
- Department
of Chemistry and Chemical Technology, University
of Calabria, Via P. Bucci, Rende, Cosenza87036, Italy
- GISEL—Centro
di Riferimento Nazionale per i Sistemi di Accumulo Elettrochimico
di Energia, INSTM, via G. Giusti 9, Firenze50121, Italy
| | - S. Bonizzoni
- Department
of Materials Science, University of Milano
Bicocca, Via Cozzi 55, Milano20126, Italy
| | - P. Mustarelli
- Department
of Materials Science, University of Milano
Bicocca, Via Cozzi 55, Milano20126, Italy
- GISEL—Centro
di Riferimento Nazionale per i Sistemi di Accumulo Elettrochimico
di Energia, INSTM, via G. Giusti 9, Firenze50121, Italy
| | - E. Quartarone
- Department
of Chemistry, University of Pavia, Via Taramelli 16, Pavia27100, Italy
- GISEL—Centro
di Riferimento Nazionale per i Sistemi di Accumulo Elettrochimico
di Energia, INSTM, via G. Giusti 9, Firenze50121, Italy
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8
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Mirmohammadi SA, Pasini D, Barthelat F. Modeling, design and tailoring of a tough, strong and stiff multilayered bone graft material. J Mech Behav Biomed Mater 2022; 134:105369. [DOI: 10.1016/j.jmbbm.2022.105369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/09/2022] [Indexed: 11/29/2022]
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9
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Abi‐Rafeh J, Asgari M, Troka I, Canaff L, Moussa A, Pasini D, Goltzman D. Genetic deletion of menin in mouse mesenchymal stem cells: an experimental and computational analysis. JBMR Plus 2022; 6:e10622. [PMID: 35509630 PMCID: PMC9059475 DOI: 10.1002/jbm4.10622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 02/17/2022] [Accepted: 03/06/2022] [Indexed: 11/16/2022] Open
Abstract
Loss‐of‐function mutations in the MEN1 tumor‐suppressor gene cause the multiple endocrine neoplasia type 1 syndrome. Menin, the MEN1 gene product, is expressed in many tissues, including bone, where its function remains elusive. We conditionally inactivated menin in mesenchymal stem cells (MSCs) using paired‐related homeobox 1 (Prx1)‐Cre and compared resultant skeletal phenotypes of Prx1‐Cre;Men1f/f menin‐knockout mice (KO) and wild‐type controls using in vivo and in vitro experimental approaches and mechanics simulation. Dual‐energy X‐ray absorptiometry demonstrated significantly reduced bone mineral density, and 3‐dimensional micro‐CT imaging revealed a decrease in trabecular bone volume, altered trabecular structure, and an increase in trabecular separation in KO mice at 6 and 9 months of age. Numbers of osteoblasts were unaltered, and dynamic histomorphometry demonstrated unaltered bone formation; however, osteoclast number and activity and receptor activator of NF‐κB ligand/osteoprotegerin (RANKL/OPG) mRNA profiles were increased, supporting increased osteoclastogenesis and bone resorption. In vitro, proliferative capabilities of bone marrow stem cells and differentiation of osteoblasts and mineralization were unaltered; however, osteoclast generation was increased. Gross femur geometrical alterations observed included significant reductions in length and in mid‐metaphyseal cross‐sectional area. Atomic force microscopy demonstrated significant decreases in elasticity of both cortical and trabecular bone at the nanoscale, whereas three‐point bending tests demonstrated a 30% reduction in bone stiffness; finite element analysis showed morphological changes of the femur microgeometry and a significantly diminished femur flexural rigidity. The biomechanical results demonstrated the detrimental outcome of the accelerated osteoclastic bone resorption. Our studies have a twofold implication; first, MEN1 deletion from MSCs can negatively regulate bone mass and bone biomechanics, and second, the experimental and computational biomechanical analyses employed in the present study should be applicable for improved phenotypic characterization of murine bone. Furthermore, our findings of critical menin function in bone may underpin the more severe skeletal phenotype found in hyperparathyroidism associated with loss‐of‐function of the MEN1 gene. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Jad Abi‐Rafeh
- Department of Medicine McGill University and McGill University Health Centre Montreal Quebec Canada
| | - Meisam Asgari
- Department of Mechanical Engineering McGill University, 817 Sherbrooke Street West Montreal QC Canada
- Theoretical and Applied Mechanics Program School of Engineering and Applied Science, Northwestern University, 2145 Sheridan Road Evanston IL USA
| | - Ildi Troka
- Department of Medicine McGill University and McGill University Health Centre Montreal Quebec Canada
| | - Lucie Canaff
- Department of Medicine McGill University and McGill University Health Centre Montreal Quebec Canada
| | - Ahmed Moussa
- Department of Mechanical Engineering McGill University, 817 Sherbrooke Street West Montreal QC Canada
| | - Damiano Pasini
- Department of Mechanical Engineering McGill University, 817 Sherbrooke Street West Montreal QC Canada
| | - David Goltzman
- Department of Medicine McGill University and McGill University Health Centre Montreal Quebec Canada
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10
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Qiao C, Liu L, Pasini D. Bi-Shell Valve for Fast Actuation of Soft Pneumatic Actuators via Shell Snapping Interaction. Adv Sci (Weinh) 2021; 8:e2100445. [PMID: 34061464 PMCID: PMC8336518 DOI: 10.1002/advs.202100445] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/25/2021] [Indexed: 05/28/2023]
Abstract
Rapid motion in soft pneumatic robots is typically achieved through actuators that either use a fast volume input generated from pressure control, employ an integrated power source, such as chemical explosions, or are designed to embed elastic instabilities in the body of the robot. This paper presents a bi-shell valve that can fast actuate soft actuators neither relying on the fast volume input provided by pressure control strategies nor requiring modifications to the architecture of the actuator. The bi-shell valve consists of a spherical cap and an imperfect shell with a geometrically tuned defect that enables shell snapping interaction to convert a slowly dispensed volume input into a fast volume output. This function is beyond those of current valves capable to perform fluidic flow regulation. Validated through experiments, the analysis unveils that the spherical cap sets the threshold of the snapping pressure along with the upper bounds of volume and energy output, while the imperfect shell interacts with the cap to store and deliver the desired output for rapid actuation. Geometry variations of the bi-shell valve are provided to show that the concept is versatile. A final demonstration shows that the soft valve can quickly actuate a striker.
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Affiliation(s)
- Chuan Qiao
- Department of Mechanical EngineeringMcGill UniversityMontrealQuebecH3A 0C3Canada
| | - Lu Liu
- Department of Mechanical EngineeringMcGill UniversityMontrealQuebecH3A 0C3Canada
| | - Damiano Pasini
- Department of Mechanical EngineeringMcGill UniversityMontrealQuebecH3A 0C3Canada
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11
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Callegari D, Colombi S, Nitti A, Simari C, Nicotera I, Ferrara C, Mustarelli P, Pasini D, Quartarone E. Autonomous Self-Healing Strategy for Stable Sodium-Ion Battery: A Case Study of Black Phosphorus Anodes. ACS Appl Mater Interfaces 2021; 13:13170-13182. [PMID: 33720685 PMCID: PMC8041259 DOI: 10.1021/acsami.0c22464] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Autonomic self-healing (SH), namely, the ability to repair damages from mechanical stress spontaneously, is polarizing attention in the field of new-generation electrochemical devices. This property is highly attractive to enhance the durability of rechargeable Li-ion batteries (LIBs) or Na-ion batteries (SIBs), where high-performing anode active materials (silicon, phosphorus, etc.) are strongly affected by volume expansion and phase changes upon ion insertion. Here, we applied a SH strategy, based on the dynamic quadruple hydrogen bonding, to nanosized black phosphorus (BP) anodes for Na-ion cells. The goal is to overcome drastic capacity decay and short lifetime, resulting from mechanical damages induced by the volumetric expansion/contraction upon sodiation/desodiation. Specifically, we developed novel ureidopyrimidinone (UPy)-telechelic systems and related blends with poly(ethylene oxide) as novel and green binders alternative to the more conventional ones, such as polyacrylic acid and carboxymethylcellulose, which are typically used in SIBs. BP anodes show impressively improved (more than 6 times) capacity retention when employing the new SH polymeric blend. In particular, the SH electrode still works at a current density higher than 3.5 A g-1, whereas the standard BP electrode exhibits very poor performances already at current densities lower than 0.5 A g-1. This is the result of better adhesion, buffering properties, and spontaneous damage reparation.
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Affiliation(s)
- D. Callegari
- Department
of Chemistry and INSTM, University of Pavia, Via Taramelli 16, 27100 Pavia, Italy
| | - S. Colombi
- Department
of Chemistry and INSTM, University of Pavia, Via Taramelli 16, 27100 Pavia, Italy
| | - A. Nitti
- Department
of Chemistry and INSTM, University of Pavia, Via Taramelli 16, 27100 Pavia, Italy
| | - C. Simari
- Department
of Chemistry and Chemical Technologies, Università Della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende, Cs Italy
- National
Reference Centre for Electrochemical Energy Storage (GISEL)—INSTM, Via G. Giusti 9, 50121 Firenze Italy
| | - I. Nicotera
- Department
of Chemistry and Chemical Technologies, Università Della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende, Cs Italy
- National
Reference Centre for Electrochemical Energy Storage (GISEL)—INSTM, Via G. Giusti 9, 50121 Firenze Italy
| | - C. Ferrara
- Department
of Materials Science, University of Milano
Bicocca, Via Cozzi 55, 20125 Milano, Italy
- National
Reference Centre for Electrochemical Energy Storage (GISEL)—INSTM, Via G. Giusti 9, 50121 Firenze Italy
| | - P. Mustarelli
- Department
of Materials Science, University of Milano
Bicocca, Via Cozzi 55, 20125 Milano, Italy
- National
Reference Centre for Electrochemical Energy Storage (GISEL)—INSTM, Via G. Giusti 9, 50121 Firenze Italy
| | - D. Pasini
- Department
of Chemistry and INSTM, University of Pavia, Via Taramelli 16, 27100 Pavia, Italy
| | - E. Quartarone
- Department
of Chemistry and INSTM, University of Pavia, Via Taramelli 16, 27100 Pavia, Italy
- National
Reference Centre for Electrochemical Energy Storage (GISEL)—INSTM, Via G. Giusti 9, 50121 Firenze Italy
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12
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Leng J, Xu H, Schaenzer M, Quan Pham M, Bourgeois G, Shanian A, Pasini D. Generalized tessellations of superellipitcal voids in low porosity architected materials for stress mitigation. Proc Math Phys Eng Sci 2021. [DOI: 10.1098/rspa.2020.0864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Stress concentration is a crucial source of mechanical failure in structural elements, especially those embedding voids. This paper examines periodic porous materials with porosity lower than 5%. We investigate their stress distribution under planar multiaxial loading, and presents a family of geometrically optimized void shapes for stress mitigation. We adopt a generalized description for both void geometry and planar tessellation patterns that can handle single and multiple voids of arbitrary void shape at a generic angle. The role of void shape evolution from diamond to rectellipse on the stress-distribution is captured at the edge of voids in a representative volume element (RVE) made of non-equal length periodic vectors. Theoretical derivations, numerical simulations along with experimental validation of the strain field in thermoplastic polymer samples fabricated by laser cutting unveil the role of geometric parameters, e.g. superellipse order, aspect ratio and rotation angle, that minimize stress peak and ameliorate stress distribution around voids. This work extends and complements classical theory by providing fundamental insights into the role that tessellation, void shape and inclination play in the stress distribution of low-porosity architected materials, thus introducing essential guidelines of broad application for stress-minimization and failure mitigation in diverse sectors.
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Affiliation(s)
- Jiazhen Leng
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal QC H3A 0C3, Canada
| | - Hang Xu
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal QC H3A 0C3, Canada
| | - Megan Schaenzer
- Siemens Power and Gas, 9545 Côte-de-Liesse, Dorval, QC H9P 1A5, Canada
| | - Minh Quan Pham
- Siemens Power and Gas, 9545 Côte-de-Liesse, Dorval, QC H9P 1A5, Canada
| | | | - Ali Shanian
- Siemens Power and Gas, 9545 Côte-de-Liesse, Dorval, QC H9P 1A5, Canada
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal QC H3A 0C3, Canada
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13
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Piro D, Boldrini L, Cornacchione P, Pasini D, Balducci M, Gambacorta M, Valentini V. PO-1941: Current perspectives of RTTs in radiation oncology research: a national survey in Italy. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)01958-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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14
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Piro D, Boldrini L, Cornacchione P, Votta C, Bianchi M, Balducci M, Gambacorta MA, Valentini V, Pasini D. Radiation therapy technologists' involvement and opinion in research: A national survey in Italy. Tech Innov Patient Support Radiat Oncol 2020; 15:11-14. [PMID: 32613093 PMCID: PMC7322338 DOI: 10.1016/j.tipsro.2020.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/04/2020] [Accepted: 05/14/2020] [Indexed: 10/26/2022] Open
Abstract
Introduction This survey describes Italian RTTs' involvement and opinions in research activities related to radiation oncology. Primary aim was to assess the degree of involvement of the national RTTs community in research and to describe how RTTs can integrate their skills collaborating with other professionals. Materials and methods A ten-items multiple-choice questionnaire, with 2-8 possible responses, was developed by a steering committee and generated on a survey platform. Links were sent via email to Italian RTTs.The questions were divided in 3 domains: demographic data; scientific research and activity; opinions about RTTs role in scientific research. The survey started on October 1, 2018 and ended on January 31, 2019. Results One hundred thirty-five out of 509 (26.5%) RTTs responded to the questionnaire at its expiring date; 97.73% think to be valid contributors in radiation oncology research, expressing clear interest in "data collection" tasks (52.71%); 38.64% feel unsupported by other professionals in the research team and 59.85% of the respondents are not members in any scientific society. Conclusions The role of Italian RTTs in research is heterogeneous. Mainly RTTs in the age range from 30 to 40 years responded to the survey showing their interest in scientific research. This might be related to different informatics and educational skills as well as to personal attitudes. RTTs particular skills, like data management and technical hypothesis generation abilities, are of benefit to realize research projects. Therefore, engaging RTTs in research activities is strongly suggested.
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Affiliation(s)
- D Piro
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy
| | - L Boldrini
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy.,Istituto di Radiologia, Università Cattolica del Sacro Cuore, Roma, Italy
| | - P Cornacchione
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy
| | - C Votta
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy
| | - M Bianchi
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy
| | - M Balducci
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy.,Istituto di Radiologia, Università Cattolica del Sacro Cuore, Roma, Italy
| | - M A Gambacorta
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy.,Istituto di Radiologia, Università Cattolica del Sacro Cuore, Roma, Italy
| | - V Valentini
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy.,Istituto di Radiologia, Università Cattolica del Sacro Cuore, Roma, Italy
| | - D Pasini
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy
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15
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Moussa A, Rahman S, Xu M, Tanzer M, Pasini D. Topology optimization of 3D-printed structurally porous cage for acetabular reinforcement in total hip arthroplasty. J Mech Behav Biomed Mater 2020; 105:103705. [PMID: 32279849 DOI: 10.1016/j.jmbbm.2020.103705] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/07/2020] [Accepted: 02/16/2020] [Indexed: 01/12/2023]
Abstract
Aseptic loosening and mechanical failure of acetabular reinforcement components are among the main causes of their reduced service life. Current acetabular implants typically feature a structural solid layer that provides load bearing capacity, coated with a foam of uniform porosity to reduce stress shielding and implant loosening. This paper presents an alternative concept for a 3D printed cage that consists of a multifunctional fully porous layer with graded attributes that integrate both structural function and bone in-growth properties. The design comprises a hemispherical cup affixed to a superior flange with architecture featuring an optimally graded porosity. The methodology here presented combines an upscaling mechanics scheme of lattice materials with density-based topology optimization, and includes additive manufacturing constraints and bone ingrowth requirements in the problem formulation. The numerical results indicate a 21.4% reduction in the maximum contact stress on the bone surface, and a 26% decrease in the bone-implant interface peak micromotion, values that are indicative of enhanced bone ingrowth and implant long-term stability.
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Affiliation(s)
- Ahmed Moussa
- Department of Mechanical Engineering, McGill University, Montreal, Quebec, H3A0C3, Canada
| | - Shakurur Rahman
- Department of Mechanical Engineering, McGill University, Montreal, Quebec, H3A0C3, Canada
| | - Manman Xu
- Department of Mechanical Engineering, McGill University, Montreal, Quebec, H3A0C3, Canada
| | - Michael Tanzer
- Division of Orthopaedics, Department of Surgery, McGill University, Jo Miller Orthopaedic Research Laboratory, Montreal, Quebec, H3G1A4, Canada
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, Montreal, Quebec, H3A0C3, Canada.
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16
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Brulé V, Rafsanjani A, Asgari M, Western TL, Pasini D. Three-dimensional functional gradients direct stem curling in the resurrection plant Selaginella lepidophylla. J R Soc Interface 2019; 16:20190454. [PMID: 31662070 PMCID: PMC6833318 DOI: 10.1098/rsif.2019.0454] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/10/2019] [Indexed: 12/16/2022] Open
Abstract
Upon hydration and dehydration, the vegetative tissue of Selaginella lepidophylla can reversibly swell and shrink to generate complex morphological transformations. Here, we investigate how structural and compositional properties at tissue and cell wall levels in S. lepidophylla lead to different stem curling profiles between inner and outer stems. Our results show that directional bending in both stem types is associated with cross-sectional gradients of tissue density, cell orientation and secondary cell wall composition between adaxial and abaxial stem sides. In inner stems, longitudinal gradients of cell wall thickness and composition affect tip-to-base tissue swelling and shrinking, allowing for more complex curling as compared to outer stems. Together, these features yield three-dimensional functional gradients that allow the plant to reproducibly deform in predetermined patterns that vary depending on the stem type. This study is the first to demonstrate functional gradients at different hierarchical levels combining to operate in a three-dimensional context.
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Affiliation(s)
- Véronique Brulé
- Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, CanadaH3A 1B1
| | - Ahmad Rafsanjani
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montréal, QC, CanadaH3A 0C3
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Meisam Asgari
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montréal, QC, CanadaH3A 0C3
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL 60208, USA
| | - Tamara L. Western
- Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, CanadaH3A 1B1
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montréal, QC, CanadaH3A 0C3
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17
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Asgari M, Abi-Rafeh J, Hendy GN, Pasini D. Material anisotropy and elasticity of cortical and trabecular bone in the adult mouse femur via AFM indentation. J Mech Behav Biomed Mater 2019; 93:81-92. [DOI: 10.1016/j.jmbbm.2019.01.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/28/2019] [Accepted: 01/30/2019] [Indexed: 11/29/2022]
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18
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Dallago M, Raghavendra S, Luchin V, Zappini G, Pasini D, Benedetti M. Geometric assessment of lattice materials built via Selective Laser Melting. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.matpr.2018.11.096] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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19
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Moussa A, Tanzer M, Pasini D. Cervical fusion cage computationally optimized with porous architected Titanium for minimized subsidence. J Mech Behav Biomed Mater 2018; 85:134-151. [DOI: 10.1016/j.jmbbm.2018.05.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 05/16/2018] [Accepted: 05/29/2018] [Indexed: 11/25/2022]
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20
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Prithipaul PKM, Kokkolaras M, Pasini D. Assessment of structural and hemodynamic performance of vascular stents modelled as periodic lattices. Med Eng Phys 2018; 57:11-18. [PMID: 29759946 DOI: 10.1016/j.medengphy.2018.04.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/17/2018] [Accepted: 04/16/2018] [Indexed: 11/16/2022]
Abstract
This work considers vascular stents with tubular geometry assumed to follow a periodic arrangement of repeating unit cells. Structural and hemodynamic metrics are presented to assess alternative stent geometries, each defined by the topology of the unit cell. Structural metrics include foreshortening, elastic recoil and radial stiffness, whereas hemodynamic performance is described by a wall shear stress index quantifying the impact of in-stent restenosis. A representative volume element (RVE) modelling approach is used, and results are compared to those obtained from full simulations of entire stents. We demonstrate that the RVE approach can be used to quantify the impact of the topology of the repeating unit on the structural and hemodynamic properties of a stent, and thus support clinicians in making proper choices among alternative stent geometries.
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Affiliation(s)
- Purnendu K M Prithipaul
- Department of Mechanical Engineering, McGill University, 817 Sherbrook St. West, Montreal, Quebec, H3A 0C3, Canada.
| | - Michael Kokkolaras
- Department of Mechanical Engineering, McGill University, 817 Sherbrook St. West, Montreal, Quebec, H3A 0C3, Canada.
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, 817 Sherbrook St. West, Montreal, Quebec, H3A 0C3, Canada.
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21
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Rahimizadeh A, Nourmohammadi Z, Arabnejad S, Tanzer M, Pasini D. Porous architected biomaterial for a tibial-knee implant with minimum bone resorption and bone-implant interface micromotion. J Mech Behav Biomed Mater 2018; 78:465-479. [DOI: 10.1016/j.jmbbm.2017.11.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 11/16/2017] [Accepted: 11/25/2017] [Indexed: 01/04/2023]
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22
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Melancon D, Bagheri ZS, Johnston RB, Liu L, Tanzer M, Pasini D. Mechanical characterization of structurally porous biomaterials built via additive manufacturing: experiments, predictive models, and design maps for load-bearing bone replacement implants. Acta Biomater 2017; 63:350-368. [PMID: 28927929 DOI: 10.1016/j.actbio.2017.09.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 08/30/2017] [Accepted: 09/12/2017] [Indexed: 11/18/2022]
Abstract
Porous biomaterials can be additively manufactured with micro-architecture tailored to satisfy the stringent mechano-biological requirements imposed by bone replacement implants. In a previous investigation, we introduced structurally porous biomaterials, featuring strength five times stronger than commercially available porous materials, and confirmed their bone ingrowth capability in an in vivo canine model. While encouraging, the manufactured biomaterials showed geometric mismatches between their internal porous architecture and that of its as-designed counterpart, as well as discrepancies between predicted and tested mechanical properties, issues not fully elucidated. In this work, we propose a systematic approach integrating computed tomography, mechanical testing, and statistical analysis of geometric imperfections to generate statistical based numerical models of high-strength additively manufactured porous biomaterials. The method is used to develop morphology and mechanical maps that illustrate the role played by pore size, porosity, strut thickness, and topology on the relations governing their elastic modulus and compressive yield strength. Overall, there are mismatches between the mechanical properties of ideal-geometry models and as-manufactured porous biomaterials with average errors of 49% and 41% respectively for compressive elastic modulus and yield strength. The proposed methodology gives more accurate predictions for the compressive stiffness and the compressive strength properties with a reduction of the average error to 11% and 7.6%. The implications of the results and the methodology here introduced are discussed in the relevant biomechanical and clinical context, with insight that highlights promises and limitations of additively manufactured porous biomaterials for load-bearing bone replacement implants. STATEMENT OF SIGNIFICANCE In this work, we perform mechanical characterization of load-bearing porous biomaterials for bone replacement over their entire design space. Results capture the shift in geometry and mechanical properties between as-designed and as-manufactured biomaterials induced by additive manufacturing. Characterization of this shift is crucial to ensure appropriate manufacturing of bone replacement implants that enable biological fixation through bone ingrowth as well as mechanical property harmonization with the native bone tissue. In addition, we propose a method to include manufacturing imperfections in the numerical models that can reduce the discrepancy between predicted and tested properties. The results give insight into the use of structurally porous biomaterials for the design and additive fabrication of load-bearing implants for bone replacement.
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Affiliation(s)
- D Melancon
- Mechanical Engineering Department, McGill University, Montreal, Quebec H3G 1A4, Canada
| | - Z S Bagheri
- Mechanical Engineering Department, McGill University, Montreal, Quebec H3G 1A4, Canada
| | - R B Johnston
- Mechanical Engineering Department, McGill University, Montreal, Quebec H3G 1A4, Canada
| | - L Liu
- Mechanical Engineering Department, McGill University, Montreal, Quebec H3G 1A4, Canada
| | - M Tanzer
- Division of Orthopaedics, Department of Surgery, McGill University, Montreal, Quebec H3G 1A4, Canada
| | - D Pasini
- Mechanical Engineering Department, McGill University, Montreal, Quebec H3G 1A4, Canada.
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23
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Arabnejad S, Johnston B, Tanzer M, Pasini D. Fully porous 3D printed titanium femoral stem to reduce stress-shielding following total hip arthroplasty. J Orthop Res 2017; 35:1774-1783. [PMID: 27664796 DOI: 10.1002/jor.23445] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 09/15/2016] [Indexed: 02/04/2023]
Abstract
Current hip replacement femoral implants are made of fully solid materials which all have stiffness considerably higher than that of bone. This mechanical mismatch can cause significant bone resorption secondary to stress shielding, which can lead to serious complications such as peri-prosthetic fracture during or after revision surgery. In this work, a high strength fully porous material with tunable mechanical properties is introduced for use in hip replacement design. The implant macro geometry is based off of a short stem taper-wedge implant compatible with minimally invasive hip replacement surgery. The implant micro-architecture is fine-tuned to locally mimic bone tissue properties which results in minimum bone resorption secondary to stress shielding. We present a systematic approach for the design of a 3D printed fully porous hip implant that encompasses the whole activity spectrum of implant development, from concept generation, multiscale mechanics of porous materials, material architecture tailoring, to additive manufacturing, and performance assessment via in vitro experiments in composite femurs. We show that the fully porous implant with an optimized material micro-structure can reduce the amount of bone loss secondary to stress shielding by 75% compared to a fully solid implant. This result also agrees with those of the in vitro quasi-physiological experimental model and the corresponding finite element model for both the optimized fully porous and fully solid implant. These studies demonstrate the merit and the potential of tuning material architecture to achieve a substantial reduction of bone resorption secondary to stress shielding. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1774-1783, 2017.
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Affiliation(s)
- Sajad Arabnejad
- Department of Mechanical Engineering, McGill University, Macdonald Engineering Building, Rm 372, 817 rue Sherbrooke Ouest, Montreal, Quebec, H3A0C3, Canada
| | - Burnett Johnston
- Department of Mechanical Engineering, McGill University, Macdonald Engineering Building, Rm 372, 817 rue Sherbrooke Ouest, Montreal, Quebec, H3A0C3, Canada
| | - Michael Tanzer
- Division of Orthopaedics, Department of Surgery, McGill University, Jo Miller Orthopaedic Research Laboratory, Montreal, Quebec, H3G1A4, Canada
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, Macdonald Engineering Building, Rm 372, 817 rue Sherbrooke Ouest, Montreal, Quebec, H3A0C3, Canada
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24
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Mattiucci G, De Filippo L, Dinapoli N, Boldrini L, Chiesa S, Bianchi M, Canna R, Cellini F, Chiloiro G, Deodato F, Macchia G, Indellicati C, Pasini D, Morganti A, Valentini V. EP-1254: DVH analysis of radiotherapy of upper gastrointestinal tumours: a model to predict toxicity. Radiother Oncol 2017. [DOI: 10.1016/s0167-8140(17)31689-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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25
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Rofouie P, Pasini D, Rey AD. Multiple-wavelength surface patterns in models of biological chiral liquid crystal membranes. Soft Matter 2017; 13:541-545. [PMID: 27976774 DOI: 10.1039/c6sm02619b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a model to investigate the formation of surface patterns in biological materials through the interaction of anisotropic interfacial tension, bending elasticity, and capillarity at their free surfaces. Focusing on the cholesteric liquid crystal (CLC) material model, the generalized shape equation for anisotropic interfaces using the Rapini-Papoular anchoring and Helfrich free energies is applied to understand the formation of multi-length scale patterns, such as those found in floral petals. The chiral liquid crystal-membrane model is shown to be analogous to a driven pendulum, a connection that enables generic pattern classification as a function of bending elasticity, liquid crystal chirality and anchoring strength. The unique pattern-formation mechanism emerging from the model here presented is based on the nonlinear interaction between bending-driven folding and anchoring-driven creasing. The predictions are shown to capture accurately the two-scale wrinkling of certain tulips. These new findings enable not only to establish a new paradigm for characterizing surface wrinkling in biological liquid crystals, but also to inspire the design of functional surface structures.
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Affiliation(s)
- P Rofouie
- Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2, Canada.
| | - D Pasini
- Department of Mechanical Engineering, McGill University, 817 Sherbrook West, Montreal, Quebec H3A 0C3, Canada
| | - A D Rey
- Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2, Canada.
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26
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Faisal TR, Hristozov N, Western TL, Rey A, Pasini D. The twist-to-bend compliance of the Rheum rhabarbarum petiole: integrated computations and experiments. Comput Methods Biomech Biomed Engin 2016; 20:343-354. [PMID: 27626758 DOI: 10.1080/10255842.2016.1233328] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Plant petioles can be considered as hierarchical cellular structures, displaying geometric features defined at multiple length scales. Their macroscopic mechanical properties are the cumulative outcome of structural properties attained at each level of the structural hierarchy. This work appraises the compliance of a rhubarb stalk by determining the stalk's bending and torsional stiffness both computationally and experimentally. In our model, the irregular cross-sectional shape of the petiole and the layers of the constituent tissues are considered to evaluate the stiffness properties at the structural level. The arbitrary shape contour of the petiole is generated with reasonable accuracy by the Gielis superformula. The stiffness and architecture of the constituent layered tissues are modeled by using the concept of shape transformers so as to obtain the computational twist-to-bend ratio for the petiole. The rhubarb stalk exhibits a ratio of flexural to torsional stiffness 4.04 (computational) and 3.83 (experimental) in comparison with 1.5 for isotropic, incompressible, circular cylinders, values that demonstrate the relative structural compliance to flexure and torsion.
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Affiliation(s)
- Tanvir R Faisal
- a Department of Mechanical Engineering , McGill University , Montreal , Canada.,b Department of Mechanical Engineering , University of Manitoba , Winnipeg , Canada
| | - Nicolay Hristozov
- c Department of Biology , McGill University , Montreal , Canada.,d Department of Cellular and Molecular Medicine , University of Ottawa , Ottawa , Canada
| | | | - Alejandro Rey
- e Department of Chemical Engineering , McGill University , Montreal , Canada
| | - Damiano Pasini
- a Department of Mechanical Engineering , McGill University , Montreal , Canada
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27
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Abstract
Plants must meet mechanical as well as physiological and reproductive requirements for survival. Management of internal and external stresses is achieved through their unique hierarchical architecture. Stiffness is determined by a combination of morphological (geometrical) and compositional variables that vary across multiple length scales ranging from the whole plant to organ, tissue, cell and cell wall levels. These parameters include, among others, organ diameter, tissue organization, cell size, density and turgor pressure, and the thickness and composition of cell walls. These structural parameters and their consequences on plant stiffness are reviewed in the context of work on stems of the genetic reference plant Arabidopsis thaliana (Arabidopsis), and the suitability of Arabidopsis as a model system for consistent investigation of factors controlling plant stiffness is put forward. Moving beyond Arabidopsis, the presence of morphological parameters causing stiffness gradients across length-scales leads to beneficial emergent properties such as increased load-bearing capacity and reversible actuation. Tailoring of plant stiffness for old and new purposes in agriculture and forestry can be achieved through bioengineering based on the knowledge of the morphological and compositional parameters of plant stiffness in combination with gene identification through the use of genetics.
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Affiliation(s)
- Veronique Brulé
- Department of Biology, McGill University, 1205 Docteur Penfield Ave., Montreal, QC, H3A 1B1, Canada.
| | - Ahmad Rafsanjani
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, QC, H3A OC3, Canada.
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, QC, H3A OC3, Canada.
| | - Tamara L Western
- Department of Biology, McGill University, 1205 Docteur Penfield Ave., Montreal, QC, H3A 1B1, Canada.
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28
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Bagheri ZS, Melancon D, Liu L, Johnston RB, Pasini D. Compensation strategy to reduce geometry and mechanics mismatches in porous biomaterials built with Selective Laser Melting. J Mech Behav Biomed Mater 2016; 70:17-27. [PMID: 27184707 DOI: 10.1016/j.jmbbm.2016.04.041] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/21/2016] [Accepted: 04/27/2016] [Indexed: 11/28/2022]
Abstract
The accuracy of Additive Manufacturing processes in fabricating porous biomaterials is currently limited by their capacity to render pore morphology that precisely matches its design. In a porous biomaterial, a geometric mismatch can result in pore occlusion and strut thinning, drawbacks that can inherently compromise bone ingrowth and severely impact mechanical performance. This paper focuses on Selective Laser Melting of porous microarchitecture and proposes a compensation scheme that reduces the morphology mismatch between as-designed and as-manufactured geometry, in particular that of the pore. A spider web analog is introduced, built out of Ti-6Al-4V powder via SLM, and morphologically characterized. Results from error analysis of strut thickness are used to generate thickness compensation relations expressed as a function of the angle each strut formed with the build plane. The scheme is applied to fabricate a set of three-dimensional porous biomaterials, which are morphologically and mechanically characterized via micro Computed Tomography, mechanically tested and numerically analyzed. For strut thickness, the results show the largest mismatch (60% from the design) occurring for horizontal members, reduces to 3.1% upon application of the compensation. Similar improvement is observed also for the mechanical properties, a factor that further corroborates the merit of the design-oriented scheme here introduced.
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Affiliation(s)
- Zahra S Bagheri
- Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3G 1A4
| | - David Melancon
- Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3G 1A4
| | - Lu Liu
- Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3G 1A4
| | - R Burnett Johnston
- Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3G 1A4
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3G 1A4.
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Mast M, Leech M, Coffey M, Moura F, Ostavics A, Pasini D, Vaandering A. SP-0217: The ESTRO perspective - a guideline for positioning of head and neck patients. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)31466-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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30
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Mróz MM, Benedini S, Forni A, Botta C, Pasini D, Cariati E, Virgili T. Long-living optical gain induced by solvent viscosity in a push–pull molecule. Phys Chem Chem Phys 2016; 18:18289-96. [DOI: 10.1039/c6cp02988d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The combination of continuum and ultrafast pump–probe spectroscopy, in viscous and non-viscous environments, with DFT and TDDFT calculations, is effective in unraveling important features of the twisted intramolecular charge transfer mechanism in a new push–pull molecule that possesses aggregation induced emission properties.
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Affiliation(s)
- M. M. Mróz
- IFN-CNR, Dipartimento di Fisica
- Politecnico di Milano
- 20132 Milano
- Italy
| | - S. Benedini
- Department of Chemistry and INSTM Research Unit
- University of Pavia
- 27100 Pavia
- Italy
| | - A. Forni
- ISTM – CNR
- c/o Dipartimento di Chimica
- Università degli Studi di Milano and INSTM Research Unit
- 20133 Milano
- Italy
| | - C. Botta
- ISMAC – CNR and INSTM Research Unit
- 20133 Milano
- Italy
| | - D. Pasini
- Department of Chemistry and INSTM Research Unit
- University of Pavia
- 27100 Pavia
- Italy
| | - E. Cariati
- Università degli Studi di Milano and INSTM Research Unit
- Dipartimento di Chimica
- 20133 Milano
- Italy
| | - T. Virgili
- IFN-CNR, Dipartimento di Fisica
- Politecnico di Milano
- 20132 Milano
- Italy
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31
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Arabnejad S, Burnett Johnston R, Pura JA, Singh B, Tanzer M, Pasini D. High-strength porous biomaterials for bone replacement: A strategy to assess the interplay between cell morphology, mechanical properties, bone ingrowth and manufacturing constraints. Acta Biomater 2016; 30:345-356. [PMID: 26523335 DOI: 10.1016/j.actbio.2015.10.048] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 10/26/2015] [Accepted: 10/29/2015] [Indexed: 12/21/2022]
Abstract
High-strength fully porous biomaterials built with additive manufacturing provide an exciting opportunity for load-bearing orthopedic applications. While factors controlling their mechanical and biological response have recently been the subject of intense research, the interplay between mechanical properties, bone ingrowth requirements, and manufacturing constraints, is still unclear. In this paper, we present two high-strength stretch-dominated topologies, the Tetrahedron and the Octet truss, as well as an intuitive visualization method to understand the relationship of cell topology, pore size, porosity with constraints imposed by bone ingrowth requirements and additive manufacturing. 40 samples of selected porosities are fabricated using Selective Laser Melting (SLM), and their morphological deviations resulting from SLM are assessed via micro-CT. Mechanical compression testing is used to obtain stiffness and strength properties, whereas bone ingrowth is assessed in a canine in vivo model at four and eight weeks. The results show that the maximum strength and stiffness ranged from 227.86±10.15 to 31.37±2.19MPa and 4.58±0.18 to 1.23±0.40GPa respectively, and the maximum 0.2% offset strength is almost 5 times stronger than that of tantalum foam. For Tetrahedron samples, bone ingrowth after four and eight weeks is 28.6%±11.6%, and 41.3%±4.3%, while for the Octet truss 35.5%±1.9% and 56.9%±4.0% respectively. This research is the first to demonstrate the occurrence of bone ingrowth into high-strength porous biomaterials which have higher structural efficiency than current porous biomaterials in the market. STATEMENT OF SIGNIFICANCE We present two stretch-dominated cell topologies for porous biomaterials that can be used for load-bearing orthopaedic applications, and prove that they encourage bone ingrowth in a canine model. We also introduce an intuitive method to visualize and understand the relationship of cell topology, pore size, porosity with constraints imposed by bone ingrowth requirements and additive manufacturing. We show this strategy helps to gain insight into the interaction of exogenous implant factors and endogenous system factors that can affect the success of load-bearing orthopaedic devices.
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Valentini C, Boldrini L, Mattiucci G, Mantini G, Chiloiro G, Pasini D, Bral S, Turian J, Chu J, Valentini V. Multicenter Autocontouring Effectiveness Evaluation in Lung Cancer. Int J Radiat Oncol Biol Phys 2015. [DOI: 10.1016/j.ijrobp.2015.07.2119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
A snapping mechanical metamaterial is designed, which exhibits a sequential snap-through behavior under tension. The tensile response of this mechanical metamaterial can be altered by tuning the architecture of the snapping segments to achieve a range of nonlinear mechanical responses, including monotonic, S-shaped, plateau, and non-monotonic snap-through behavior.
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Affiliation(s)
- Ahmad Rafsanjani
- Mechanical Engineering Department, McGill University, 817 Sherbrooke Street West, Montreal, QC H3A OC3, Canada
| | - Abdolhamid Akbarzadeh
- Mechanical Engineering Department, McGill University, 817 Sherbrooke Street West, Montreal, QC H3A OC3, Canada
- Bioresource Engineering Department, McGill University, 21111 Lakeshore Road, Ste-Anne-de-BellevueIsland of Montreal, QC H9X 3V9, Canada
| | - Damiano Pasini
- Mechanical Engineering Department, McGill University, 817 Sherbrooke Street West, Montreal, QC H3A OC3, Canada
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34
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Affiliation(s)
- P. Rofouie
- Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2, Canada
| | - D. Pasini
- Department of Mechanical Engineering, McGill University, 817 Sherbrook West, Montreal, Quebec H3A 0C3, Canada
| | - A. D. Rey
- Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2, Canada
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35
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Valentini C, Boldrini L, Chiloiro G, Mattiucci G, Mantini G, Pasini D, Dinapoli N, Caria N, Valentini V. OC-0561: Hypothesis-generating prospective study for auto-delineation in lung tumors: READY LUNG-01. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)40556-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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36
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Abstract
We present theoretical scaling and computational analysis of nanostructured free surfaces formed in chiral liquid crystals (LC) and plant-based twisted plywoods. A nemato-capillary model is used to derive a generalized equation that governs the shape of cholesteric free surfaces. It is shown that the shape equation includes three distinct contributions to the capillary pressure: area dilation, area rotation, and director curvature. To analyse the origin of periodic reliefs in plywood surfaces, these three pressure contributions and corresponding surface energies are systematically investigated. It is found that for weak homeotropic surface anchoring, the nano-wrinkling is driven by the director curvature pressure mechanism. Consequently, the model predicts that for a planar surface with a uniform tangential helix vector, no surface nano-scale wrinkling can be observed because the director curvature pressure is zero. Scaling is used to derive the explicit relation between the wrinkling's amplitude to the wavelength ratio as a function of the anisotropic surface tension, which is then validated with experimental values. These new findings can be used to characterize plant-based twisted plywoods, as well as to inspire the design of biomimetic chiro-optical devices.
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Affiliation(s)
- Pardis Rofouie
- Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2, Canada.
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37
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Rafsanjani A, Brulé V, Western TL, Pasini D. Hydro-responsive curling of the resurrection plant Selaginella lepidophylla. Sci Rep 2015; 5:8064. [PMID: 25623361 PMCID: PMC4306918 DOI: 10.1038/srep08064] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/31/2014] [Indexed: 11/16/2022] Open
Abstract
The spirally arranged stems of the spikemoss Selaginella lepidophylla, an ancient resurrection plant, compactly curl into a nest-ball shape upon dehydration. Due to its spiral phyllotaxy, older outer stems on the plant interlace and envelope the younger inner stems forming the plant centre. Stem curling is a morphological mechanism that limits photoinhibitory and thermal damages the plant might experience in arid environments. Here, we investigate the distinct conformational changes of outer and inner stems of S. lepidophylla triggered by dehydration. Outer stems bend into circular rings in a relatively short period of desiccation, whereas inner stems curl slowly into spirals due to hydro-actuated strain gradient along their length. This arrangement eases both the tight packing of the plant during desiccation and its fast opening upon rehydration. The insights gained from this work shed light on the hydro-responsive movements in plants and might contribute to the development of deployable structures with remarkable shape transformations in response to environmental stimuli.
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Affiliation(s)
- Ahmad Rafsanjani
- Mechanical Engineering Department, McGill University, 817 Sherbrooke Street West, Montréal, QC, H3A OC3, Canada
| | - Véronique Brulé
- Biology Department, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, H3A 1B1, Canada
| | - Tamara L Western
- Biology Department, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, H3A 1B1, Canada
| | - Damiano Pasini
- Mechanical Engineering Department, McGill University, 817 Sherbrooke Street West, Montréal, QC, H3A OC3, Canada
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38
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Valentini C, Boldrini L, Chiloiro G, Mattiucci G, Mantini G, Pasini D, Dinapoli N, Chiesa S, Caria N, Valentini V. Validation of a Prerelease Commercial Autosegmentation Software for SBRT and 4DRT Purposes in Lung Cancer: Ready (Research Program in Auto-Delineation System)-Lung-01–Proof of Concept. Int J Radiat Oncol Biol Phys 2014. [DOI: 10.1016/j.ijrobp.2014.05.1951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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39
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Javid F, Pasini D, Angeles J. A New Surgical Barbed Staple for Minimally Invasive Surgery1. J Med Device 2014. [DOI: 10.1115/1.4027118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Farhad Javid
- Centre for Intelligent Machines (CIM) and Department of Mechanical Engineering, McGill University, Montreal, QC H3A 0C3, Canada e-mail:
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, Macdonald Engineering Building, 817 Sherbrooke St. West, Montreal, QC H3A 2K6, Canada
| | - Jorge Angeles
- Department of Mechanical Engineering, McGill University, McConnell Engineering Building 452, 817 Sherbrooke St. West, Montreal, QC H3A 2K6, Canada
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40
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Crespo Alonso M, Arca M, Isaia F, Lai R, Lippolis V, Callear SK, Caricato M, Pasini D, Coles SJ, Aragoni MC. Stereospecific generation of homochiral helices in coordination polymers built from enantiopure binaphthyl-based ligands. CrystEngComm 2014. [DOI: 10.1039/c4ce01101e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The novel enantiopure spacer 2,2′-dimethoxy-1,1′-binaphthyl-3,3′-bis(4-pyridyl-amido) has been designed to prepare helical coordination polymers here investigated by means of experimental and theoretical data.
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Affiliation(s)
- M. Crespo Alonso
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Cittadella Universitaria
- 09042 Monserrato Cagliari, Italy
| | - M. Arca
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Cittadella Universitaria
- 09042 Monserrato Cagliari, Italy
| | - F. Isaia
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Cittadella Universitaria
- 09042 Monserrato Cagliari, Italy
| | - R. Lai
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Cittadella Universitaria
- 09042 Monserrato Cagliari, Italy
| | - V. Lippolis
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Cittadella Universitaria
- 09042 Monserrato Cagliari, Italy
| | - S. K. Callear
- ISIS Facility
- Rutherford Appleton Laboratory
- Didcot, UK
| | - M. Caricato
- Department of Chemistry and INSTM Research Unit
- University of Pavia
- 27100 Pavia, Italy
| | - D. Pasini
- Department of Chemistry and INSTM Research Unit
- University of Pavia
- 27100 Pavia, Italy
| | - S. J. Coles
- UK National Crystallography Service
- Chemistry
- Faculty of Natural and Environmental Sciences
- University of Southampton
- Southampton, UK
| | - M. C. Aragoni
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Cittadella Universitaria
- 09042 Monserrato Cagliari, Italy
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41
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Valentini C, Mattiucci G, Boldrini L, Pasini D, Chiloiro G, Balducci M, Mantini G, Chiesa S, Gambacorta M, Valentini V. PD-0131: Is the perfect agreement among delineators a chimera? Analysis of interobserver variability in H&N and rectal tumors. Radiother Oncol 2014. [DOI: 10.1016/s0167-8140(15)30236-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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42
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Mattiucci G, Placidi L, Boldrini L, Azario L, Piccari D, Mazzarella C, Pasini D, Dinapoli N, Chiesa S, Valentini V. PD-0133: A dosimetric analysis of Dice index and Hausdorff distance in H&N: Which index can evaluate autocontouring software? Radiother Oncol 2014. [DOI: 10.1016/s0167-8140(15)30238-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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43
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44
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Gambacorta M, Valentini C, Dinapoli N, Boldrini L, Barba M, Mattiucci G, Pasini D, Manfrida S, Caria N, Valentini V. PO-0752: Reliability and feasibility of automatic segmentation in rectal cancer: a perspective study. Radiother Oncol 2013. [DOI: 10.1016/s0167-8140(15)33058-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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45
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Gambacorta M, Valentini C, Dinapoli N, Mattiucci G, Pasini D, Barba M, Manfrida S, Boldrini L, Caria N, Valentini V. Atlas-based Auto-segmentation Clinical Validation of Pelvic Volumes and Normal Tissue in Rectal Tumors. Int J Radiat Oncol Biol Phys 2012. [DOI: 10.1016/j.ijrobp.2012.07.916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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46
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D'Agostino G, Chiloiro G, Boldrini L, Mattiucci G, Caria N, Dinapoli N, Pasini D, Gambacorta M, Valentini V. Dice Similarity Index Assessment in Deformable Registration for Head-and-Neck Cancer Patients Undergoing Replanning Procedures. Int J Radiat Oncol Biol Phys 2012. [DOI: 10.1016/j.ijrobp.2012.07.2114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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47
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Faisal TR, Hristozov N, Rey AD, Western TL, Pasini D. Experimental determination of Philodendron melinonii and Arabidopsis thaliana tissue microstructure and geometric modeling via finite-edge centroidal Voronoi tessellation. Phys Rev E Stat Nonlin Soft Matter Phys 2012; 86:031921. [PMID: 23030958 DOI: 10.1103/physreve.86.031921] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 08/09/2012] [Indexed: 06/01/2023]
Abstract
Plant petioles and stems are hierarchical cellular structures, displaying structural features defined at multiple length scales. One or more of the intermediate hierarchical levels consists of tissues, in which the cellular distribution is quasirandom. The current work focuses on the realistic modeling of plant tissue microstructures. The finite-edge centroidal Voronoi tessellation (FECVT) is here introduced to overcome the drawbacks of the semi-infinite edges of a typical Voronoi model. FECVT can generate a realistic model of a tissue microstructure, which might have finite edges at its border, be defined by a boundary contour of any shape, and include complex heterogeneity and cellular gradients. The centroid-based Voronoi tessellation is applied to model the microstructure of the Philodendron melinonii petiole and the Arabidopsis thaliana stem, which both display intense cellular gradients. FECVT coupled with a digital image processing algorithm is implemented to capture the nonperiodic microstructures of plant tissues. The results obtained via this method satisfactorily obey the geometric, statistical, and topological laws of naturally evolved cellular solids. The predicted models are also validated by experimental data.
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Affiliation(s)
- Tanvir R Faisal
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke St. West, Montreal, QC H3A 0C3, Canada.
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48
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Gambacorta M, Valentini C, Dinapoli N, Mattiucci G, Pasini D, Barba M, Manfrida S, Boldrini L, Caria N, Valentini V. PO-0851 CLINICAL VALIDATION OF ATLAS-BASED AUTO-SEGMENTATION OF PELVIC VOLUMES AND NORMAL TISSUE IN RECTAL TUMORS. Radiother Oncol 2012. [DOI: 10.1016/s0167-8140(12)71184-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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49
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Arabnejad Khanoki S, Pasini D. Multiscale Design and Multiobjective Optimization of Orthopedic Hip Implants with Functionally Graded Cellular Material. J Biomech Eng 2012; 134:031004. [DOI: 10.1115/1.4006115] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Revision surgeries of total hip arthroplasty are often caused by a deficient structural compatibility of the implant. Two main culprits, among others, are bone-implant interface instability and bone resorption. To address these issues, in this paper we propose a novel type of implant, which, in contrast to current hip replacement implants made of either a fully solid or a foam material, consists of a lattice microstructure with nonhomogeneous distribution of material properties. A methodology based on multiscale mechanics and design optimization is introduced to synthesize a graded cellular implant that can minimize concurrently bone resorption and implant interface failure. The procedure is applied to the design of a 2D left implanted femur with optimized gradients of relative density. To assess the manufacturability of the graded cellular microstructure, a proof-of-concept is fabricated by using rapid prototyping. The results from the analysis are used to compare the optimized cellular implant with a fully dense titanium implant and a homogeneous foam implant with a relative density of 50%. The bone resorption and the maximum value of interface stress of the cellular implant are found to be over 70% and 50% less than the titanium implant while being 53% and 65% less than the foam implant.
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Affiliation(s)
| | - Damiano Pasini
- Mechanical Engineering Department, McGill University, Montreal, Quebec, Canada, H3A 0C3
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50
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Abstract
A new percutaneous annuloplasty technique for mitral regurgitation is proposed here. In this technique, inter-related anchors are first inserted around the annulus via a trans-septal catheter. The tethered wire passed through the anchors is then pulled to shrink the annulus and stop regurgitation. The anchors should withstand large deformation, applied during the delivery process, and should recover their original shape after being released inside the tissue. The shape of the anchors is, thus, optimized in an iterative process, to avoid stress concentration by minimizing the weighted rms value of the curvature along the anchor. The weight coefficients in each iteration are defined based on the stress distribution of the anchor obtained in the previous iteration. The procedure finally results in a structurally optimum anchor with a minimum in the maximum von Mises stress. This anchor is fabricated from Nitinol and tested in a cadaveric swine heart.
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Affiliation(s)
- Farhad Javid
- Centre for Intelligent Machines (CIM) andDepartment of Mechanical Engineering, McGill University, Montreal, Quebec, H3A 0C3
| | - Jorge Angeles
- ASME Fellow
- Centre for Intelligent Machines (CIM) andDepartment of Mechanical Engineering, McGill University, Montreal, Quebec, H3A 0C3
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, Montreal, Quebec, H3A 0C3
| | - Renzo Cecere
- Biosurgery and Design Unit,Department of Surgery, McGill University Health Centre, Montreal, Quebec, H3A 1A1
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