{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T06:46:26Z","timestamp":1776840386253,"version":"3.51.2"},"reference-count":54,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2022,3,7]],"date-time":"2022-03-07T00:00:00Z","timestamp":1646611200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Department of Surgery of the University Hospital Basel (Martin Allg\u00f6wer Grant)","award":["-"],"award-info":[{"award-number":["-"]}]},{"name":"IAOMS Foundation","award":["-"],"award-info":[{"award-number":["-"]}]},{"name":"Werner Siemens Foundation (MIRACLE project)","award":["-"],"award-info":[{"award-number":["-"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>Cranioplasty with freehand-molded polymethylmethacrylate implants is based on decades of experience and is still frequently used in clinical practice. However, data confirming the fracture toughness and standard biomechanical tests are rare. This study aimed to determine the amount of force that could be applied to virtually planned, template-molded, patient-specific implants (n = 10) with an implant thickness of 3 mm, used in the treatment of a temporoparietal skull defect (91.87 cm2), until the implant cracks and finally breaks. Furthermore, the influence of the weight and porosity of the implant on its force resistance was investigated. The primary outcome showed that a high force was required to break the implant (mean and standard deviation 1484.6 \u00b1 167.7 N), and this was very strongly correlated with implant weight (Pearson\u2019s correlation coefficient 0.97; p &lt; 0.001). Secondary outcomes were force application at the implant\u2019s first, second, and third crack. Only a moderate correlation could be found between fracture force and the volume of porosities (Pearson\u2019s correlation coefficient 0.59; p = 0.073). The present study demonstrates that an implant thickness of 3 mm for a temporoparietal skull defect can withstand sufficient force to protect the brain. Greater implant weight and, thus, higher material content increases thickness, resulting in more resistance. Porosities that occur during the described workflow do not seem to reduce resistance. Therefore, precise knowledge of the fracture force of polymethylmethacrylate cranial implants provides insight into brain injury prevention and serves as a reference for the virtual design process.<\/jats:p>","DOI":"10.3390\/ma15051970","type":"journal-article","created":{"date-parts":[[2022,3,7]],"date-time":"2022-03-07T10:21:16Z","timestamp":1646648476000},"page":"1970","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Biomechanical Evaluation of Patient-Specific Polymethylmethacrylate Cranial Implants for Virtual Surgical Planning: An In-Vitro Study"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0885-1195","authenticated-orcid":false,"given":"Bilal","family":"Msallem","sequence":"first","affiliation":[{"name":"Clinic of Oral and Cranio-Maxillofacial Surgery, University Hospital Basel, CH-4031 Basel, Switzerland"},{"name":"Medical Additive Manufacturing Research Group (Swiss MAM), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4502-3655","authenticated-orcid":false,"given":"Michaela","family":"Maintz","sequence":"additional","affiliation":[{"name":"Medical Additive Manufacturing Research Group (Swiss MAM), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Florian S.","family":"Halbeisen","sequence":"additional","affiliation":[{"name":"Basel Institute for Clinical Epidemiology and Biostatistics, Department of Clinical Research, University Hospital Basel, University of Basel, CH-4031 Basel, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Simon","family":"Meyer","sequence":"additional","affiliation":[{"name":"Clinic of Oral and Cranio-Maxillofacial Surgery, University Hospital Basel, CH-4031 Basel, Switzerland"},{"name":"Medical Additive Manufacturing Research Group (Swiss MAM), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7701-1993","authenticated-orcid":false,"given":"Guido R.","family":"Sigron","sequence":"additional","affiliation":[{"name":"Clinic of Oral and Cranio-Maxillofacial Surgery, Cantonal Hospital Aarau, CH-5001 Aarau, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3299-0945","authenticated-orcid":false,"given":"Neha","family":"Sharma","sequence":"additional","affiliation":[{"name":"Clinic of Oral and Cranio-Maxillofacial Surgery, University Hospital Basel, CH-4031 Basel, Switzerland"},{"name":"Medical Additive Manufacturing Research Group (Swiss MAM), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7112-2257","authenticated-orcid":false,"given":"Shuaishuai","family":"Cao","sequence":"additional","affiliation":[{"name":"Clinic of Oral and Cranio-Maxillofacial Surgery, University Hospital Basel, CH-4031 Basel, Switzerland"},{"name":"Medical Additive Manufacturing Research Group (Swiss MAM), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3035-9308","authenticated-orcid":false,"given":"Florian M.","family":"Thieringer","sequence":"additional","affiliation":[{"name":"Clinic of Oral and Cranio-Maxillofacial Surgery, University Hospital Basel, CH-4031 Basel, Switzerland"},{"name":"Medical Additive Manufacturing Research Group (Swiss MAM), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,3,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"E19","DOI":"10.3171\/2014.2.FOCUS13561","article-title":"Materials used in cranioplasty: A history and analysis","volume":"36","author":"Shah","year":"2014","journal-title":"Neurosurg. Focus"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"650","DOI":"10.1097\/00001665-200209000-00011","article-title":"Craniofacial reconstruction with computer-generated HTR patient-matched implants: Use in primary bony tumor excision","volume":"13","author":"Eppley","year":"2002","journal-title":"J. Craniofac. Surg."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"106","DOI":"10.1002\/bjs.18003313003","article-title":"Acrylic resin for the closure of skull defects","volume":"33","author":"Small","year":"1945","journal-title":"Br. J. Surg."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"199","DOI":"10.3171\/jns.1946.3.3.0199","article-title":"Cranioplasty with acrylic plates","volume":"3","author":"Elkins","year":"1946","journal-title":"J. Neurosurg."},{"key":"ref_5","first-page":"588","article-title":"Repairing holes in the head: A history of cranioplasty","volume":"40","author":"Sanan","year":"1997","journal-title":"Neurosurgery"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"705","DOI":"10.3171\/2015.10.PEDS15489","article-title":"Surgical results of cranioplasty with a polymethylmethacrylate customized cranial implant in pediatric patients: A single-center experience","volume":"17","author":"Fiaschi","year":"2016","journal-title":"J. Neurosurg. Pediatr."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"S289","DOI":"10.1097\/SAP.0000000000001801","article-title":"Alloplastic Cranioplasty Reconstruction: A Systematic Review Comparing Outcomes with Titanium Mesh, Polymethyl Methacrylate, Polyether Ether Ketone, and Norian Implants in 3591 Adult Patients","volume":"82","author":"Oliver","year":"2019","journal-title":"Ann. Plast. Surg."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"535","DOI":"10.1007\/s00701-006-0740-6","article-title":"Analyses of the factors influencing bone graft infection after delayed cranioplasty","volume":"148","author":"Matsuno","year":"2006","journal-title":"Acta Neurochir."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1016\/j.jocn.2008.04.001","article-title":"Cranioplasty using polymethyl methacrylate prostheses","volume":"16","author":"Lee","year":"2009","journal-title":"J. Clin. Neurosci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1055\/s-0037-1604362","article-title":"Outcomes of Cranioplasty with Preformed Titanium versus Freehand Molded Polymethylmethacrylate Implants","volume":"79","author":"Werzmirzowsky","year":"2018","journal-title":"J. Neurol. Surg. A Cent. Eur. Neurosurg."},{"key":"ref_11","first-page":"e31","article-title":"Complications with PMMA compared with other materials used in cranioplasty: A systematic review and meta-analysis","volume":"32","author":"Maior","year":"2018","journal-title":"Braz. Oral Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"705","DOI":"10.1097\/00006534-199909010-00014","article-title":"Osseointegration of preformed polymethylmethacrylate craniofacial prostheses coated with bone marrow-impregnated poly (DL-lactic-co-glycolic acid) foam","volume":"104","author":"Dean","year":"1999","journal-title":"Plast. Reconstr. Surg."},{"key":"ref_13","first-page":"156","article-title":"Preliminary focus on the mechanical and antibacterial activity of a PMMA-based bone cement loaded with gold nanoparticles","volume":"2","author":"Russo","year":"2017","journal-title":"Bioact. Mater."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"409","DOI":"10.1002\/jbm.b.31963","article-title":"Antimicrobial acrylic materials with in situ generated silver nanoparticles","volume":"100","author":"Oei","year":"2012","journal-title":"J. Biomed. Mater. Res. B Appl. Biomater."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"915","DOI":"10.1016\/j.clineuro.2010.07.013","article-title":"Laboratory confirmed polymethyl-methacrylate (Palacos)-hypersensitivity after cranioplasty","volume":"112","author":"Gautschi","year":"2010","journal-title":"Clin. Neurol. Neurosurg."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1016\/j.jcms.2020.10.002","article-title":"A systematic review of cranioplasty material toxicity in human subjects","volume":"49","author":"Las","year":"2021","journal-title":"J. Craniomaxillofac. Surg."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"617","DOI":"10.1016\/j.jocn.2009.09.005","article-title":"Temperature elevation during simulated polymethylmethacrylate (PMMA) cranioplasty in a cadaver model","volume":"17","author":"Golz","year":"2010","journal-title":"J. Clin. Neurosci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1179\/1743132812Y.0000000007","article-title":"Aesthetic outcome in patients after polymethyl-methacrylate (PMMA) cranioplasty\u2014A questionnaire-based single-centre study","volume":"34","author":"Fischer","year":"2012","journal-title":"Neurol. Res."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/j.brainresbull.2019.08.010","article-title":"The application of polyetheretherketone (PEEK) implants in cranioplasty","volume":"153","author":"Zhang","year":"2019","journal-title":"Brain Res. Bull."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"e1582","DOI":"10.1097\/GOX.0000000000001582","article-title":"Craniofacial Reconstruction by a Cost-Efficient Template-Based Process Using 3D Printing","volume":"5","author":"Msallem","year":"2017","journal-title":"Plast. Reconstr. Surg. Glob. Open"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Zanjanijam, A.R., Major, I., Lyons, J.G., Lafont, U., and Devine, D.M. (2020). Fused Filament Fabrication of PEEK: A Review of Process-Structure-Property Relationships. Polymers, 12.","DOI":"10.3390\/polym12081665"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"5255","DOI":"10.1016\/j.polymer.2014.08.045","article-title":"Crystallization behavior and morphological characterization of poly(ether ether ketone)","volume":"55","author":"Jin","year":"2014","journal-title":"Polymer"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Dua, R., Rashad, Z., Spears, J., Dunn, G., and Maxwell, M. (2021). Applications of 3D-Printed PEEK via Fused Filament Fabrication: A Systematic Review. Polymers, 13.","DOI":"10.3390\/polym13224046"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"4520636","DOI":"10.1155\/2018\/4520636","article-title":"Patient-Specific Surgical Implants Made of 3D Printed PEEK: Material, Technology, and Scope of Surgical Application","volume":"2018","author":"Honigmann","year":"2018","journal-title":"Biomed Res. Int."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"e356","DOI":"10.1016\/j.wneu.2020.12.138","article-title":"3D-Printer-Assisted Patient-Specific Polymethyl Methacrylate Cranioplasty: A Case Series of 16 Consecutive Patients","volume":"148","author":"Skalicky","year":"2021","journal-title":"World Neurosurg."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"38","DOI":"10.17159\/2078-5151\/2018\/v56n3a2521","article-title":"Evaluation of locally manufactured patient-specific custom made implants for cranial defects using a silicone mould","volume":"56","author":"Vlok","year":"2018","journal-title":"S. Afr. J. Surg."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Chamo, D., Msallem, B., Sharma, N., Aghlmandi, S., Kunz, C., and Thieringer, F.M. (2020). Accuracy Assessment of Molded, Patient-Specific Polymethylmethacrylate Craniofacial Implants Compared to Their 3D Printed Originals. J. Clin. Med., 9.","DOI":"10.3390\/jcm9030832"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1002\/jbmr.2613","article-title":"Evaluation of Skull Cortical Thickness Changes with Age and Sex from Computed Tomography Scans","volume":"31","author":"Lillie","year":"2016","journal-title":"J. Bone Miner. Res."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1055\/s-0033-1343788","article-title":"The thickness of parietal bones in a new zealand sample of cadaveric skulls in relation to calvarial bone graft","volume":"6","author":"Choi","year":"2013","journal-title":"Craniomaxillofac. Trauma Reconstr."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1097\/00001665-199705000-00013","article-title":"Thickness map of parietal bone in Korean adults","volume":"8","author":"Hwang","year":"1997","journal-title":"J. Craniofac. Surg."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"648","DOI":"10.1097\/00006534-198505000-00005","article-title":"The calvarial donor site: An anatomic study in cadavers","volume":"75","author":"Pensler","year":"1985","journal-title":"Plast. Reconstr. Surg."},{"key":"ref_32","first-page":"1508","article-title":"Strength analysis of human skull on high speed impact","volume":"6","author":"Siswanto","year":"2012","journal-title":"Int. Rev. Mech. Eng."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Ridwan-Pramana, A., Marci\u00e1n, P., Bor\u00e1k, L., Narra, N., Forouzanfar, T., and Wolff, J. (2017). Finite element analysis of 6 large PMMA skull reconstructions: A multi-criteria evaluation approach. PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0179325"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/j.compbiomed.2019.04.016","article-title":"Biomechanical performance of cranial implants with different thicknesses and material properties: A finite element study","volume":"109","author":"Narra","year":"2019","journal-title":"Comput. Biol. Med."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1016\/j.jcms.2015.10.014","article-title":"Structural and mechanical implications of PMMA implant shape and interface geometry in cranioplasty\u2014A finite element study","volume":"44","author":"Narra","year":"2016","journal-title":"J. Craniomaxillofac. Surg."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"140","DOI":"10.1097\/00001665-200501000-00028","article-title":"Biomechanical testing of alloplastic PMMA cranioplasty materials","volume":"16","author":"Eppley","year":"2005","journal-title":"J. Craniofac. Surg."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1551","DOI":"10.1097\/SCS.0000000000001882","article-title":"Comparison of Autogenous and Alloplastic Cranioplasty Materials Following Impact Testing","volume":"26","author":"Wallace","year":"2015","journal-title":"J. Craniofac. Surg."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1016\/j.matpr.2019.04.188","article-title":"Strength analysis of Cranioplasty PMMA flap material","volume":"15","author":"Archana","year":"2019","journal-title":"Mater. Today Proc."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Msallem, B., Sharma, N., Cao, S., Halbeisen, F.S., Zeilhofer, H.F., and Thieringer, F.M. (2020). Evaluation of the Dimensional Accuracy of 3D-Printed Anatomical Mandibular Models Using FFF, SLA, SLS, MJ, and BJ Printing Technology. J. Clin. Med., 9.","DOI":"10.3390\/jcm9030817"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1097\/00001665-200303000-00003","article-title":"Clinical outcome in cranioplasty: Critical review in long-term follow-up","volume":"14","author":"Jackson","year":"2003","journal-title":"J. Craniofac. Surg."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1007\/s10439-016-1668-5","article-title":"3D-Printing Technologies for Craniofacial Rehabilitation, Reconstruction, and Regeneration","volume":"45","author":"Nyberg","year":"2017","journal-title":"Ann. Biomed. Eng."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1186\/s41205-021-00096-7","article-title":"Cranioplasty with three-dimensional customised mould for polymethylmethacrylate implant: A series of 16 consecutive patients with cost-effectiveness consideration","volume":"7","author":"Lobo","year":"2021","journal-title":"3D Print. Med."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2479","DOI":"10.1016\/j.jbiomech.2009.07.018","article-title":"Tolerance of the skull to blunt ballistic temporo-parietal impact","volume":"42","author":"Raymond","year":"2009","journal-title":"J. Biomech."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1007\/s11517-015-1317-4","article-title":"Temporal bone fracture under lateral impact: Biomechanical and macroscopic evaluation","volume":"54","author":"Montava","year":"2016","journal-title":"Med. Biol. Eng. Comput."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Allsop, D., Perl, T., and Warner, C. (1991). Force\/Deflection and Fracture Characteristics of the Temporo-parietal Region of the Human Head. SAE Technical Paper 912907, SAE International.","DOI":"10.4271\/912907"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1492","DOI":"10.1097\/PRS.0b013e3181ef8bb1","article-title":"Evaluation of skull strength following parietal bone graft harvest","volume":"126","author":"Laure","year":"2010","journal-title":"Plast. Reconstr. Surg."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"329","DOI":"10.1016\/j.jcms.2017.11.020","article-title":"Comparative finite element analysis of skull mechanical properties following parietal bone graft harvesting in adults","volume":"46","author":"Haen","year":"2018","journal-title":"J. Craniomaxillofac. Surg."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1603","DOI":"10.1007\/s00414-019-02102-4","article-title":"A biomechanical comparison between human calvarial bone and a skull simulant considering the role of attached periosteum and dura mater","volume":"133","author":"Ondruschka","year":"2019","journal-title":"Int. J. Legal Med."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"2129","DOI":"10.1016\/j.jbiomech.2009.05.030","article-title":"The mechanical properties of cranial bone: The effect of loading rate and cranial sampling position","volume":"42","author":"Motherway","year":"2009","journal-title":"J. Biomech."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1028","DOI":"10.1054\/arth.2000.8188","article-title":"Fracture and fatigue properties of acrylic bone cement: The effects of mixing method, sterilization treatment, and molecular weight","volume":"15","author":"Graham","year":"2000","journal-title":"J. Arthroplast."},{"key":"ref_51","first-page":"110","article-title":"Porosity in manually mixed bone cement","volume":"231","year":"1988","journal-title":"Clin. Orthop. Relat. Res."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"536","DOI":"10.3109\/17453678408992954","article-title":"Strength of polymethylmethacrylate increased by vacuum mixing","volume":"55","author":"Lidgren","year":"1984","journal-title":"Acta Orthop. Scand."},{"key":"ref_53","unstructured":"(2018). PALACOS\u00aeR\u2014High Viscosity, Radiopaque Bone Cement, Heraeus Medical GmbH. Available online: https:\/\/www.heraeus.com\/media\/media\/hme\/doc_hme\/products_hme\/palacos_bone_cement\/r_rg_mv_mvg_lv_lvg\/ifu\/PALACOS_R_IFU.pdf."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"13","DOI":"10.3389\/fbioe.2013.00013","article-title":"Development of a Human Cranial Bone Surrogate for Impact Studies","volume":"1","author":"Roberts","year":"2013","journal-title":"Front. Bioeng. Biotechnol."}],"container-title":["Materials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1944\/15\/5\/1970\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:33:20Z","timestamp":1760135600000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1944\/15\/5\/1970"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,3,7]]},"references-count":54,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2022,3]]}},"alternative-id":["ma15051970"],"URL":"https:\/\/doi.org\/10.3390\/ma15051970","relation":{},"ISSN":["1996-1944"],"issn-type":[{"value":"1996-1944","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,3,7]]}}}