{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,16]],"date-time":"2026-01-16T07:46:36Z","timestamp":1768549596856,"version":"3.49.0"},"reference-count":54,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,1,15]],"date-time":"2026-01-15T00:00:00Z","timestamp":1768435200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: This study aims to analyze the effects of levetiracetam (LEV) and valproic acid (VPA) administration on oxidative stress, inflammation, apoptosis, extracellular matrix dynamics, and bone remodeling parameters in rat alveolar bone exposed to orthodontic force. Materials and Methods: Four experimental groups were designed for this study: Control, Force, Force + LEV, and Force + VPA. LEV (150 mg\/kg\/day) or VPA (300 mg\/kg\/day) was administered intraperitoneally to the experimental groups daily for 6 weeks. At the end of the experimental period, the alveolar bone tissues were used for molecular analyses. RT-PCR analysis was performed to assess the expression levels of antioxidant markers [superoxide dismutase, (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH)], inflammatory cytokines [tumor necrosis factor alpha (TNF-\u03b1) and interleukin-1 beta (IL-1\u03b2)], apoptosis-related genes (Bax, Bcl-2, and Caspase-3), matrix remodeling genes [matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and metallopeptidase inhibitor 1 (TIMP-1)], and bone metabolism regulators [receptor activator of nuclear factor kappa-\u0392 ligand (RANKL) and osteoprotegerin (OPG)]. Oxidative stress and inflammatory measurements were also confirmed via ELISA assays. Results: The results demonstrated that orthodontic force application increased oxidative stress, inflammation, and apoptosis compared to the Control group, disrupted extracellular matrix homeostasis, and increased bone resorption, while LEV administration (LEV + Force) markedly mitigated these abnormalities. In other words, LEV administration increased levels of antioxidant markers, decreased levels of inflammatory cytokines and pro-apoptotic genes, restored extracellular matrix balance (decrease in MMP-2 and MMP-9 with concurrent upregulation of TIMP-1), and limited tissue destruction (decrease in RANKL along with elevation in OPG). In contrast to LEV, VPA did not correct these molecular alterations induced by orthodontic force and, in several parameters, further exacerbated them. Conclusions: In conclusion, molecular data from the animal model indicate that LEV plays a protective role against orthodontic force by reducing excess levels of oxidative stress, apoptosis, and inflammation and homeostatic pathways.<\/jats:p>","DOI":"10.3390\/medicina62010178","type":"journal-article","created":{"date-parts":[[2026,1,15]],"date-time":"2026-01-15T12:31:41Z","timestamp":1768480301000},"page":"178","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Molecular Investigation of the Effects of Two Antiepileptic Drugs (Valproic Acid and Levetiracetam) on Alveolar Bone Under Orthodontic Force"],"prefix":"10.3390","volume":"62","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2223-7984","authenticated-orcid":false,"given":"Nurhan","family":"Bayindir-Durna","sequence":"first","affiliation":[{"name":"Faculty of Dentistry, Atat\u00fcrk University, Erzurum 25240, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Metin","family":"Uckan","sequence":"additional","affiliation":[{"name":"Faculty of Dentistry, Atat\u00fcrk University, Erzurum 25240, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-5640-3363","authenticated-orcid":false,"given":"Seyma","family":"Aydin","sequence":"additional","affiliation":[{"name":"Department of Genetics, Faculty of Veterinary Medicine, Atat\u00fcrk University, Erzurum 25240, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7539-0523","authenticated-orcid":false,"given":"Selcuk","family":"Ozdemir","sequence":"additional","affiliation":[{"name":"Department of Genetics, Faculty of Veterinary Medicine, Atat\u00fcrk University, Erzurum 25240, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1620\/tjem.221.265","article-title":"Orthodontic force accelerates dentine mineralization during tooth development in juvenile rats","volume":"221","author":"Kong","year":"2010","journal-title":"Tohoku J. Exp. Med."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Zhu, C., Li, R., Yuan, L., Zheng, Y., Jin, Y., Li, H., Liu, C., Xia, L., and Fang, B. (2022). Effects of the advanced mandibular spring on mandibular retrognathia treatment: A three-dimensional finite element study. BMC Oral Health, 22.","DOI":"10.1186\/s12903-022-02308-w"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1053\/j.sodo.2024.02.006","article-title":"Biomechanical considerations for tooth movement and strategies to avoid undesirable side effects","volume":"30","author":"Jacob","year":"2024","journal-title":"Semin. Orthod."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Wang, X., Xue, J., Wang, X., and Fan, M. (2025). Biomechanical Effects of Orthodontic Tooth Movement on Edentulous Alveolar Bone: A Finite Element Analysis. Front. Bioeng. Biotechnol., 13.","DOI":"10.3389\/fbioe.2025.1625027"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Li, Y., Zhan, Q., Bao, M., Yi, J., and Li, Y. (2021). Biomechanical and biological responses of periodontium in orthodontic tooth movement: Up-date in a new decade. Int. J. Oral Sci., 13.","DOI":"10.1038\/s41368-021-00125-5"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Tang, Z., and Yang, Y. (2025). Mechanobiology in orthodontic tooth movement: Update on knowledge and clinical implications. Semin. Orthod., in press.","DOI":"10.1053\/j.sodo.2025.10.009"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Yan, T., Xie, Y., He, H., Fan, W., and Huang, F. (2021). Role of nitric oxide in orthodontic tooth movement (Review). Int. J. Mol. Med., 48.","DOI":"10.3892\/ijmm.2021.5001"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Hosseini, S., Diegelmann, J., Folwaczny, M., Sabbagh, H., Otto, S., Kakoschke, T.K., Wichelhaus, A., Baumert, U., and Janjic Rankovic, M. (2024). Investigation of Oxidative-Stress Impact on Human Osteoblasts During Orthodontic Tooth Movement Using an In Vitro Tension Model. Int. J. Mol. Sci., 25.","DOI":"10.3390\/ijms252413525"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"297","DOI":"10.11005\/jbm.2023.30.4.297","article-title":"Mechanisms of Osteoclastogenesis in Orthodontic Tooth Movement and Orthodontically Induced Tooth Root Resorption","volume":"30","author":"Nakai","year":"2023","journal-title":"J. Bone Metab."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Wang, M., Zhang, L., Lin, F., Zheng, Q., Xu, X., and Mei, L. (2021). Dynamic study into autophagy and apoptosis during orthodontic tooth movement. Exp. Ther. Med., 21.","DOI":"10.3892\/etm.2021.9847"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Kapoor, P., Kharbanda, O.P., Monga, N., Miglani, R., and Kapila, S. (2014). Effect of orthodontic forces on cytokine and receptor levels in gingival crevicular fluid: A systematic review. Prog. Orthod., 15.","DOI":"10.1186\/s40510-014-0065-6"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/j.freeradbiomed.2019.12.016","article-title":"Orthodontic force-induced oxidative stress in the periodontal tissue and dental pulp elicits nociception via activation\/sensitization of TRPA1 on nociceptive fibers","volume":"147","author":"Morii","year":"2020","journal-title":"Free Radic. Biol. Med."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Yamaguchi, M., and Fukasawa, S. (2021). Is Inflammation a Friend or Foe for Orthodontic Treatment?: Inflammation in Orthodontically Induced Inflammatory Root Resorption and Accelerating Tooth Movement. Int. J. Mol. Sci., 22.","DOI":"10.3390\/ijms22052388"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1945","DOI":"10.2147\/NDT.S256117","article-title":"Effects of levetiracetam compared to valproate on cognitive functions of patients with epilepsy","volume":"16","author":"Hamdi","year":"2020","journal-title":"Neuropsychiatr. Dis. Treat."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"176","DOI":"10.4103\/nsn.nsn_28_23","article-title":"Valproate-Induced Nonhyperammonemic Encephalopathy with Electroencephalogram Background Slowing and Triphasic Waves","volume":"40","author":"Dericioglu","year":"2023","journal-title":"Neurol. Sci. Neurophysiol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Pathak, S.M., Ziechmann, R., Menzer, J., Hoeft, A., and Villanueva, P. (2023). Discontinuation of Levetiracetam and Valproic Acid Due to Adverse Effects in Early Post-traumatic Seizure Prophylaxis. Cureus, 15.","DOI":"10.7759\/cureus.47742"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Wang, S., Wu, X., Xue, T., Song, Z., Tan, X., Sun, X., and Wang, Z. (2023). Efficacy and safety of levetiracetam versus valproate in patients with established status epilepticus: A systematic review and meta-analysis. Heliyon, 9.","DOI":"10.1016\/j.heliyon.2023.e13380"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"983","DOI":"10.14219\/jada.archive.1979.0419","article-title":"Valproic acid: A new antiepileptic drug with potential side effects of dental concern","volume":"99","author":"Hassell","year":"1979","journal-title":"J. Am. Dent. Assoc."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"278","DOI":"10.4103\/0972-124X.99277","article-title":"Sodium valproate induced gingival enlargement with pre-existing chronic periodontitis","volume":"16","author":"Joshipura","year":"2012","journal-title":"J. Indian Soc. Periodontol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"168","DOI":"10.4103\/jpgm.jpgm_1059_21","article-title":"Levetiracetam-induced gingival hyperplasia","volume":"68","author":"James","year":"2022","journal-title":"J. Postgrad. Med."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1695","DOI":"10.1002\/epi4.70051","article-title":"Gingival enlargement following levetiracetam treatment: A clinical case analysis","volume":"10","author":"Alahmari","year":"2025","journal-title":"Epilepsia Open"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"83","DOI":"10.5698\/1535-7597-13.2.83","article-title":"Levetiracetam treatment does not result in broken bones","volume":"13","author":"Pack","year":"2013","journal-title":"Epilepsy Curr."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Xie, X., Cheng, P., Hu, L., Zhou, W., Zhang, D., Knoedler, S., Liu, G., Xiong, Y., Xue, H., and Hu, Y. (2024). Bone-targeting engineered small extracellular vesicles carrying anti-miR-6359-CGGGAGC prevent valproic acid-induced bone loss. Signal Transduct. Target. Ther., 9.","DOI":"10.1038\/s41392-023-01726-8"},{"key":"ref_24","unstructured":"University of Iowa Institutional Animal Care and Use Committee (2025, December 20). Anesthesia (Guideline): Vertebrate Animal Research. Available online: https:\/\/animal.research.uiowa.edu\/iacuc-guidelines-anesthesia."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"446","DOI":"10.1016\/j.bone.2007.04.194","article-title":"Local delivery of osteoprotegerin inhibits mechanically mediated bone modeling in orthodontic tooth movement","volume":"41","author":"Dunn","year":"2007","journal-title":"Bone"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"843","DOI":"10.1016\/j.ajodo.2007.11.035","article-title":"Effect of alendronate on orthodontic tooth movement in rats","volume":"136","author":"Karras","year":"2009","journal-title":"Am. J. Orthod. Dentofac. Orthop."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Davila, J.E., Miller, J.R., Hodges, J.S., Beyer, J.P., and Larson, B.E. (2011). Effect of neonatal capsaicin treatment on orthodontic tooth movement in male Sprague-Dawley rats. Am. J. Orthod. Dentofac. Orthop., 139.","DOI":"10.1016\/j.ajodo.2009.07.019"},{"key":"ref_28","first-page":"73","article-title":"Decreased bone density induced by antiepileptic drugs can cause accelerated orthodontic tooth movement in male Wistar rats","volume":"16","author":"Akhoundi","year":"2018","journal-title":"Int. Orthod."},{"key":"ref_29","first-page":"3433","article-title":"Valproic acid prevents glucocorticoid-induced osteonecrosis of the femoral head of rats","volume":"41","author":"Zhou","year":"2018","journal-title":"Int. J. Mol. Med."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1850","DOI":"10.1111\/j.1528-1167.2007.01176.x","article-title":"Levetiracetam, phenytoin, and valproate act differently on rat bone mass, structure, and metabolism","volume":"48","author":"Svalheim","year":"2007","journal-title":"Epilepsia"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.bone.2018.05.011","article-title":"The anti-epileptic drugs valproate, carbamazepine and levetiracetam cause bone loss and modulate Wnt inhibitors in normal and ovariectomised rats","volume":"113","author":"Parveen","year":"2018","journal-title":"Bone"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1323","DOI":"10.1007\/s43440-020-00087-1","article-title":"Effects of carbamazepine, eslicarbazepine, valproic acid and levetiracetam on bone microarchitecture in rats","volume":"72","author":"Diemar","year":"2020","journal-title":"Pharmacol. Rep."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Hosseini, S., Diegelmann, J., Folwaczny, M., Frasheri, I., Wichelhaus, A., Sabbagh, H., Seidel, C., Baumert, U., and Janjic Rankovic, M. (2024). Investigation of Impact of Oxidative Stress on Human Periodontal Ligament Cells Exposed to Static Compression. Int. J. Mol. Sci., 25.","DOI":"10.3390\/ijms252413513"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Inchingolo, F., Inchingolo, A.M., Latini, G., Ferrante, L., Trilli, I., Del Vecchio, G., Palmieri, G., Malcangi, G., Inchingolo, A.D., and Dipalma, G. (2023). Oxidative Stress and Natural Products in Orthodontic Treatment: A Systematic Review. Nutrients, 16.","DOI":"10.3390\/nu16010113"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Suttorp, C.M., Xie, R., Lundvig, D.M., Kuijpers-Jagtman, A.M., Uijttenboogaart, J.T., Van Rheden, R., Maltha, J.C., and Wagener, F.A. (2016). Orthodontic forces induce the cytoprotective enzyme heme oxygenase-1 in rats. Front. Physiol., 7.","DOI":"10.3389\/fphys.2016.00283"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"4225","DOI":"10.1007\/s00784-023-05039-6","article-title":"Oxidative stress and genotoxicity in oral epithelial cells from subjects undergoing orthodontic treatment with fixed appliances","volume":"27","year":"2023","journal-title":"Clin. Oral Investig."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"469.e1","DOI":"10.1016\/j.ajodo.2005.10.007","article-title":"Cellular, molecular, and tissue-level reactions to orthodontic force","volume":"129","author":"Krishnan","year":"2006","journal-title":"Am. J. Orthod. Dentofac. Orthop."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"250","DOI":"10.1111\/j.1529-8027.2011.00355.x","article-title":"Levetiracetam exhibits protective properties on rat Schwann cells in vitro","volume":"16","author":"Stettner","year":"2011","journal-title":"J. Peripher. Nerv. Syst."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"94","DOI":"10.1016\/j.neulet.2010.01.018","article-title":"Levetiracetam inhibits interleukin-1 beta inflammatory responses in the hippocampus and piriform cortex of epileptic rats","volume":"471","author":"Kim","year":"2010","journal-title":"Neurosci. Lett."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Yao, X., Yang, W., Ren, Z., Zhang, H., Shi, D., Li, Y., Yu, Z., Guo, Q., Yang, G., and Gu, Y. (2021). Neuroprotective and Angiogenesis Effects of Levetiracetam Following Ischemic Stroke in Rats. Front. Pharmacol., 12.","DOI":"10.3389\/fphar.2021.638209"},{"key":"ref_41","first-page":"156","article-title":"Mechanobiology of orthodontic tooth movement: An update","volume":"12","author":"Maltha","year":"2023","journal-title":"J. World Fed. Orthod."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Fernandes, M.R.U., Martinez, E.F., Teti, G., Suzuki, S.S., and Aranha, A.C.C. (2025). Effect of Simvastatin Combined with Photobiomodulation Therapy on Orthodontic Tooth Movement and the Expression of Metalloproteinases and Inhibitors-An Experimental Study. Lasers Med. Sci., 40.","DOI":"10.1007\/s10103-025-04443-6"},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"He, L., Wang, X., Chen, Z., Yang, K., Yan, L., Zhang, R., Li, Y., and Huang, S. (2025). Identification of novel candidate immune biomarkers linked to osteoclast activity during orthodontic tooth movement in a mouse model. Eur. J. Orthod., 47.","DOI":"10.1093\/ejo\/cjaf087"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1007\/s00056-019-00205-6","article-title":"Effects of orthodontic force magnitude on cell apoptosis and RANKL-induced osteoclastogenesis: Studies in a rat model","volume":"81","author":"Kaya","year":"2020","journal-title":"J. Orofac. Orthop."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Danz, J.C., and Degen, M. (2025). Selective modulation of the bone remodeling regulatory system through orthodontic tooth movement\u2014A review. Front. Oral Health, 6.","DOI":"10.3389\/froh.2025.1472711"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Steinberg, T., Jung, B., Husari, A., Bai, S., and Tomakidi, P. (2025). Shaping Orthodontics of the Future: Concepts and Implications from a Cellular and Molecular Perspective. Int. J. Mol. Sci., 26.","DOI":"10.3390\/ijms26178203"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1016\/j.eplepsyres.2008.03.008","article-title":"Fish liver oil and propolis as protective natural products against the effect of the anti-epileptic drug valproate on immunological markers of bone formation in rats","volume":"80","author":"Elwakkad","year":"2008","journal-title":"Epilepsy Res."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1016\/j.seizure.2017.03.013","article-title":"The effect of VPA on bone: From clinical studies to cell cultures-The molecular mechanisms revisited","volume":"48","author":"Pitetzis","year":"2017","journal-title":"Seizure"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/j.jot.2020.10.006","article-title":"Parathyroid hormone (1\u201334) can reverse the negative effect of valproic acid on the osseointegration of titanium rods in ovariectomized rats","volume":"27","author":"Tao","year":"2021","journal-title":"J. Orthop. Translat."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1016\/j.eplepsyres.2013.08.012","article-title":"The effect of levetiracetam on rat bone mass, structure and metabolism","volume":"107","author":"Fekete","year":"2013","journal-title":"Epilepsy Res."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"993","DOI":"10.1080\/17512433.2017.1353418","article-title":"The effect of antiepileptic drugs on the kidney function and structure","volume":"10","author":"Hamed","year":"2017","journal-title":"Expert Rev. Clin. Pharmacol."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"1003","DOI":"10.1007\/s40200-021-00960-7","article-title":"Effect of inflammation on bones in diabetic patients with periodontitis via RANKL\/OPG system-A review","volume":"21","author":"Ateeq","year":"2022","journal-title":"J. Diabetes Metab. Disord."},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Ren, J., Fok, M.R., Zhang, Y., Han, B., and Lin, Y. (2023). The role of non-steroidal anti-inflammatory drugs as adjuncts to periodontal treatment and in periodontal regeneration. J. Transl. Med., 21.","DOI":"10.1186\/s12967-023-03990-2"},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Zhao, Z., Chen, L., Zhu, S., Yu, H., Chen, Y., Song, J., Liu, Y., and He, D. (2025). Periodontal ligament stem cells in tissue remodeling: From mechanical forces to inflammatory signals. Stem Cell Res. Ther., 16.","DOI":"10.1186\/s13287-025-04777-6"}],"container-title":["Medicina"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1648-9144\/62\/1\/178\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,15]],"date-time":"2026-01-15T13:53:41Z","timestamp":1768485221000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1648-9144\/62\/1\/178"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,15]]},"references-count":54,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,1]]}},"alternative-id":["medicina62010178"],"URL":"https:\/\/doi.org\/10.3390\/medicina62010178","relation":{},"ISSN":["1648-9144"],"issn-type":[{"value":"1648-9144","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,15]]}}}