CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="390"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "www.cell.com",cType: 'managed',cRay: '8e90ea918fab899b',cH: 'f7pqnNnjQNzGgCYbL892EOcxOwOwHu586VyYr7IXeIA-1732697904-1.2.1.1-9GFOvwFuljIVvldd2ri39ERvZkONTffyNU5IbSf.ZRC69FGwsasOoJUKdxkbcyKL',cUPMDTk: "\/cell\/fulltext\/S0092-8674(20)30740-6?__cf_chl_tk=ziUWJQSG_bR4sCB_KuU6XOX6Y3s3qPNub2Ib9bcwKRM-1732697904-1.0.1.1-MqiHfINP2aPxGCukcpWsZ0BApTqqgY5hkuiVDCbCtus",cFPWv: 'b',cITimeS: '1732697904',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/cell\/fulltext\/S0092-8674(20)30740-6?__cf_chl_f_tk=ziUWJQSG_bR4sCB_KuU6XOX6Y3s3qPNub2Ib9bcwKRM-1732697904-1.0.1.1-MqiHfINP2aPxGCukcpWsZ0BApTqqgY5hkuiVDCbCtus",md: "yFfIjfceESTze3lQ2Va6vgmIUPssuiYK.bae6jy1qso-1732697904-1.2.1.1-O7e7mbnliap4m__ZAHPqUa_aX.0vYl5ZjAfvDUB7q5ob8PiDXXS8NkKhYUCohwVSbevEyZdSNCKhIojapvF1oBZ5.7mNvTw0Pry4v9b_N6lRIQHdXfni_TzL3MWK1S1bO4vQrEjs0yqktNeGVsLP8i9N_ISiYkIXZlXp1N0VquKvfa0s4reZXmymX75uUgPdQ9hWKWL8nU8rg8v8_OuIRheqQrl6rCex0ZJIKwN58QIuhQO4f0wsN_tN7IpFMB5OnoWzQ1bXcgaTpZU9XBfzgCAI2eSgvkTCmELu188B8bL_KvWQ8bNR8ybXSAlkE9i46OZ2.ppjuc.lYEP6LMwO2mv5Lf239QVqU4hxHyDHNYOF2UgBK_1q2I0xQ3H9QRfWlJx1taaeZUanKHg7PqSyfRsFc3r2ydIp4kmK5PyTzIkDHdHN_RUgsxQEhHbH9OqsBxmrNp3EXuk9fGn0uXlGPu2ZDJJXinDkJy4vvMSyhk1AxV5N3VgTNwIGtrKKIqb_iC2p2Q1JfVBRHqx0wt0RVp7YRYMY7jMaqBaVRPdnxAr6d18d_.hDcyuglOJp2fxuFPJ_VWssvplBKluZ5dH78EuOCGluflFe36Ho_Ju1zosy5FvkwCRwn5JVoDh1G2mH9Mh0v7Uku7P2En0G4ZXxwIR1PU6UrlS7c7EzzgIt1bxEbVlDCRHnOkyRN713wbA.UlIONR98MrOqHzNcgEx9Njnoe3Tm7zVT_115.PtaS6hwseLezuoGvaeCU6785jbQAX5MpehoooeB_59tZAPLzErKCFkzpBq2VQGjqMyuzwH_EuesqQk3Gu0smIXwQGS_OzQJc2VMgSAepROl4qgZbx1gjLRNAKg4YOxKabSsa.yrVF8.uWFHQQVMJD41.92As.10mG.KhZJHCWvKDVFi2ScI24XfQfuutVzXri47kxEfim.k.AfHEtoxZQx3.luyHzp1dvRT8e9OiSxYQVcbG0IF8qa6t.F58S1vf.4WSyP9HbucG5KWTDeCng9842xwYB0m6EgoFAskTQJ03aZe6wS9.HsJSgKWZB8_.dmEZbiCQVOKiZfNAZIU4_aDb1MRS8RVbOGbz1QMW59M3btqxyhStx10WzaTYIgk8xBrnsVaX4HUhaUJO6TAiozKy4QdeYW7.aCs1Z6myyWNAzSXwZBTVoxJr8MSH8YwPqMwgERcUZwz_veCmsMdIiYAv6LB0QOLIeCkvvkCVyx7A7Z9QHN8G3LvQF5MBfxo8Nx3Lfxrb2.nI1Ya2PoLEt9ODkLwP7l6SWethpsBZPYrMIpB2iB6ti8e50rsTQZny9hs7sDB8QXs0ksLYwZIDXQWNufYWUxLSMRoqpQf2UcMT_hkex5Cvkb7jeUU.qkUdcRmvA4dwtQ0DkBoFf_HdwZ6VJ8kA_dhmLtiyINU.jlXxNPMPaw5eFeliKzut32zyYRcUtFkokgkO6vqkeJ7uT.lg5M6dpRSjZd4hjfoHX4bRaT09tnZybMaCc8hhFRgK5PMiKjOY5f6LRq4EcTC8E9iDqCsEIHb4drxxVJINo.Bbq1_prbWPUTuiMIFzI5SCQ5pO4Zc_JrzPkJ7wu.sk7rSOevGWsDCsdYgj3i_hr.Dd_q0DQX1SE_j44plfo8jaIFUSHq8sPBVw_pm_SRuDYkDW6a4uSe84DQgGHW_IIlZbhoKvTyp4A_mjbRedtOYdu3XmyjiYcTcVRew2T.tGXpm8BPrEXqmEWNgzu0C3xp5K3Lj6Znc1.R.W7JSFzdUG9leA_n.wSVfaLtvK7rZ6xGL.NqjoHzHUTZNJhbUpXXS_R77JyJwKvGV5u.KTqjcYXHNVhkPL4CyAbBwUCwcgTn_s9jJk7YdNmJqheATBgOf64m7T4b492Vk8y66YdGjm1nkepMKgJLDvRBV.f29b0R6tGo5nxDPlrq0qyKB2FYN2cu1n94bMuc7oql949Xz3wCXcTNoR2bSmXIhNlmDIuEu8zv6gmSvvi9vNkr8BddEa8FbSADEsrzJGQqjVyQq54APWYAR8Vvn9eJXQJLuZHzoUs2WLhr.P9uG6nx7z.2fdGIKk7zvgptkv.5cE0SE8QdVkARmp0f3TY9R3t0m4WCadRaWmq7E6CDsQNPq.XFfFcOpGGEzPHXAPRlwKLrSE1zmkU0qzpDXLjNQLBrdbf5yyk_4CkXdZ3q6dm8IkkSb8gzOa.V4sPua5Aqh39kXyBn5kxAHpCHia0unmJWXRXZXf4UwU1OGG8ptRvc7C6AaHLotSNtHYADqwMZNm.40mzOM_9UiMLs0JBABWNQkHse06ARZmmqHnEEz5RiRo0qULx1cxO9jSPGJzXjrD78PVYA6fxI8.mnVmp1z84Tw0BCrVi4Q5ZSEcQHdocxdO60wRiTxX6KuQ3cRVugCPdksB4CqTyL5XHvm827_9PTD6t92uarIYTyZHuV6z3EqglJEcWt2PJYxczHo9jtofpVCuzYmPtUniGgWI.fk4MDzmhwn6zRhG3iJ1rN4P3mjehXoksgcNrI8qpB5rXOFFiIQVugbLLlfkC.VrVZtYrtqFM6ZiqajJFYajIujK0MNfF_OPH6k7mP91g8tF5oYwOfLS4paAzLJPLnYVBYLU3lwAgqjAo9kCAgfLaCYeZyIEcSZnTa7mBXH6pijFdmfRxW6m917KHS6WhVnx0LHeh71n1KCbSX6yXDCaPXbkdj2o7IHyz9_IscvvH1baJwSckcRCvsCAoKUxck6Vsj7A750zCKXxP7ijKk9HOi7Kd_RICeE7emZOJwNJtxqQ2RtFCFNGFR9Z8rjl5foZYCS5l0ULaXUbBKQstD1soQGCKZUkICeOGXaR9dsrBHvDYhzqc2IWP6g6zilZTBKtk06hwZr3xUcEU4xWi5ecen4D2uuPfylDD7DQfICkCJjiVmbSt8blFOZnlVpAU5QnczxhNiEvgyNfv5Pwh75.h_D7fzUVn3Y_HyC5.I.LyOPr71GkTmFESwZF957Ik9fgsBaWlhZgIQhII3V",mdrd: "RefJA8SGHjtzii0hsulZ2yIe2kEKExNmUUMQV3Epzgg-1732697904-1.2.1.1-DB1davOwvybDkKstybDUXNoLNjWvOhjMDPTGyRhKPwwrKDDZkEW4OdRs5dy2kUhbkrLh0b86OUA2xI6XnP32jVVaruHJKAbLf46fiRug_BtHDw7TGQt0.KKk3bE8qIqiH_B43AMYl3RtMCsiNTDDWD.IFqq8EP39jBngkCffgQowJQvzHf5kfSxUs61K2RSVx5gHrIj649qawJK5sNw7WJ8LAUsRpKhAGGeA4ZHe1pzgjpP8xndsMkU5sQeT522zXdLaX7npQ7AhOgSaQy1BMgh_e_5D1QzpefNQH1P3iBFpwwdC.V3yDwopphNQqZlfdAW9frx_kO4IDXfozvYxwLOeS7WlIcHw13NOihXBhrXTefrzcBMTjchAsjDhA2xS45m7Y.o96724R8jOAj6hYW97k1gI1Ux1lLlJy5s6YSNPPrhg6i9N8bbQi3QkqRYtk85l8YIUObqThUW5KqLsFeSMeX0XJ67U1ujkUrsiukGFwYD3WEH9tsejqyzW6M44DAttCqxoZyou3C7aNWdKNpvwKSMGdaQdeCdm0wutHWbnoSNqgCLlVT8KmMRg1xU2O9kP7Mrm2vfwRR8iEP8aAADF2VcUeR_tnC_MBYf4BBWn.oJ7Ir3spfNfqZLAbTwWWqtZMkQ_iNdW3m0rdYbDT3hIA5YDX8_rAi4d3qd6xAv3ix7Vd_ph1RMfLeZuFnoOMaFHDdgMVn_343UPAcgsKhPrXbKNZcXBE.0bzpraMtm0vzMg.VdX10vjk3rmGV7gaWNZYV8cMSHMTVYQMKqOahKCna8ndSaPF1F.v_KUVc8OQDAdAse1E8yeJ59OeRrm1SzBw.JN9OAiyw.HvD4cJ9_ZD3T4CDMQSFDocajvgAO6isdCQ9IRKh_0.wXviO_oKsg8R_ZO4OMWzQD08v..nGWDOShBtObxFSMXB2v93Mi3M2D9Cq2MhVxHGrox0EEgUllWkCoU5_vFLofvsCqSzqPyHrH_TyKisf5jMONHu5ukD443USFxYRViBxaiBZ1QdDBYy8bCKBq5BV.I7Wwga2cLGtFJxeXZIYgc5qPl7uJuRl43umS_BCYFoHnmdLIaY.XXt8sd7AJqfDSsJ89j1aqPaDrhjQ0u1FIMkhTPZQm3yBncEfNksFg5DZrwboJ3Gp6VSmFvNJLMrHlTRU0lrdPywwQ898psZY9Ovy_lMEJVH_1z4zIGiVPehSgcycPZTmFXvxVpuG1LXO5vzxd8WYAqv9SSsAxWoOBky0BXNmG.5bo7muq00hoLiClpkQ0ixOLPAMOV78OdG30ZLFc4w4JL0cRHozIC_E260mbEppASHK08JnkQGUpoXtNwG_Nvwi_UeWVpfW0BuUk40NeB_cmLCLmQaHtKyo5BT9OzHgVwb6kHttf.2qWJm9QY.x_ouQdzuHpPfdLdyhSIH7tLQGDUor9R8sIxp6IR_joy3kzEvwmLkoq437z3OfHVxgNTLXaDIa79vHAQo96TuxPzpaPwvD.Q7q26HDmHa5TZgdDDpPbhN5NqZscTY2rMCUC7OK1JrLIuQv2VOWi6YgEggN00me3bUDl5GmxbjmAYSigUnxj0VmsXk8C_BBcqqOzJIr8aiY51Z4_U2nOQWmF.Q2Jkf9no7aAwBsnuIA9FO7ihw5GDn0ccEIypPvReeItGaKp9CxKbIReyeTOJlW7OTx52Mctx4JBang2nbJjCVKzTFuUHi3ClctFFLmsE3peChwtl6YTBsQTYODuDsjwnbkBT4FCVvvq.a6H.azefiSY4PCzM9HSf1lgNChfUwvYGEO153Win7foLM.jAwWwZtTnUWvkp8.NvmZ5Sy_F5fHrAniJXDhmYrglzdAU.K1kiCLItT6K2tdwT0wy.XT4B6_3lAs9zGPiheUBNh0zSALa6QJrZ7mc_xE0mNMTylnNl_gAoRhPVghXOySwyrI_4lA"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=8e90ea918fab899b';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/cell\/fulltext\/S0092-8674(20)30740-6?__cf_chl_rt_tk=ziUWJQSG_bR4sCB_KuU6XOX6Y3s3qPNub2Ib9bcwKRM-1732697904-1.0.1.1-MqiHfINP2aPxGCukcpWsZ0BApTqqgY5hkuiVDCbCtus" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>