University of California, San Francisco    About UCSF     A-Z Web Listing     UCSF Search     Campus Directory

EDUCATION:
BS                  Engineering Science. Northwestern University, 1970
PhD                Materials Science and Engineering, Northwestern University, 1975

EXPERIENCE:
1974-87         Instructor-Professor, Biological Materials, Northwestern University
1980-84         NIH-NIDCR Oral Biology and Medicine Study Section
1981              Visiting Fellow in Dental Prosthetics, University of Melbourne, Victoria, Austrailia
1987-present Professor, Preventive and Restorative Dental Sciences, University of California, San Francisco
1987-1989     President, Academy of Dental Materials
1988-2005     Vice-Chair for Research, Preventive and Restorative Dental Sciences, UCSF
1988-2000     Member, Executive Committee, Group in Biostatistics, University of California, San Francisco
1989-present Member, UCSF - UC Berkeley Joint Graduate Bioengineering Group, UCSF
1988-present Guest Staff Scientist, Lawrence Berkeley Laboratory
1991-present Member, Graduate Group in Oral Biology (Chair, 1994-1999), University of California, San Francisco
1992-present Visiting Scientist, Lawrence Livermore National Laboratory, Livermore, CA
1992-1993      President, American Association for Dental Research
1999-2000      President, International Association for Dental Research
2005-present  Vice Provost,  Academic Affairs, UCSF

PUBLICATIONS: 

Balooch M, Habelitz S, Kinney JH, Marshall SJ, Marshall GW. Mechanical properties of mineralized collagen fibrils as influenced by demineralization. J Struct Biol 2008 162:404-410 (doi: 10.1016/j.jsb.2008.02.010).
Brauer DS, Saeki K, Hilton JF, Marshall GW, Marshall SJ.  Effect of sterilization by Gamma radiation on nano-mechanical properties of teeth. Dent Mater 2008 24:1137-1140 (doi: 10.1016/j.dental.2008.02.016).
Staninec M, Nguyen H, Kim P, Marshall GW, Rithchie RO, Marshall SJ. Four-point bending evaluation of dentin-composite interfaces with various stresses. Med Oral Patol Oral Cir Bucal. 2008 13(1):E81-4.
Hsu KW, Marshall SJ, Pinzon LM, Watanabe LG, Saiz E, Marshall GW. SEM evaluation of resin-carious dentin interfaces by two dentin adhesive systems. Dental Mater 2008 24:880-887. (doi:10.1016j.dental.2007.11.001)
Staninec M, Kim P, Marshall GW, Ritchie RO, Marshall SJ.  Fatigue of dentin-composite interfaces with four-point bend.  Dental Mater  2008 24:799-803. (doi:10.1016j.dental.2007.09.008)
Ho S, Ryder M, Marshall SJ, Marshall GW. The tooth attachment mechanism defined by structure, chemical composition and mechanical properties of collagen fibers in the periodontium. Biomaterials 2007 28:5238-5245.
Habelitz S, Rodriguez BJ, Marshall SJ, Marshall GW, Kalinin SV, Gruverman A. Peritubular dentin lacks piezoelectricity J Dent Res 2007 86:908-911.
 Foppiano S,  Marshall SJ, Marshall GW, Saiz E, Tomsia AP. Bioactive glass coatings affect osteoblast-like behavior. Acta Biomaterialia 2007 3:765-771.
Saeki K, Hilton JF, Allison T, Habelitz S, Marshall SJ, Marshall GW, DenBesten P. Elevated TGF-beta signaling in dentin results in sex related enamel defects.  Arch Oral Biol 2007 52:814-21.
Foppiano S, Marshall SJ, Saiz E, Tomsia AP, Marshall GW.  Functionally graded bioactive coatings: Reproducibility and stability of the coating under cell culture conditions. Acta Biomaterialia 2006 2:133-142.
Habelitz S, Denbesten PK, Marshall SJ, Marshall GW, Li W. Self-assembly and effect on crystal growth of the leucine-rich amelogenin peptide. Eur J Oral Sci. 2006 114 Suppl 1:315-319.
Balooch G, Balooch M, Nalla RK, Schilling S, Filvaroff EH, Marshall GW, Marshall SJ, Derynck R, Alliston T. TGF-{beta} regulates the mechanical properties and composition of bone matrix. Proc Natl Acad Sci U S A. 2005 102:18813-18818.
 Habelitz S, DenBesten PK, Marshall SJ, Marshall GW, Li W. Amelogenin control over apatite crystal growth is affected by the pH and degree of ionic saturation.  Orthod Craniofacial Res. 2005 8, 232-238.
Carrillo F, Gupta S, Balooch M, Marshall SJ, Marshall GW, Pruitt L, Puttlitz C. Nanoindentation of polydimethylsiloxand elastomers: Effect of crosslinking, work of adhesion and fluid environment on elastic modulus. J Mater Res 2005 20: 2820-2830.
Ho SP, Sulyanto RM, Marshall SJ, Marshall GW. The cementum dentin junction also contains glycosaminoglycans and collagen fibrils. J Struct Biol 2005 151:69-78.
Imbeni V, Kruzic JJ, Marshall GW, Marshall SJ, Ritchie RO. The dentin-enamel junction and the fracture of human teeth. Nature Mater. 4:229-232, 2005.
Staninec M, Nalla RK, Hilton JF, Ritchie RO, Nonomura G, Marshall GW, Marshall SJ. Dentin errosion simulation by cantilever beam fatique and pH change.  J Dent Res 2005 84:371-375.
Imbeni V, Kruzic JJ, Marshall GW, Marshall SJ, Ritchie RO. The dentin-enamel junction and the fracture of human teeth. Nature Mater. 2005 4:229-232. Schulze KA, Oliveira SA, Wilson RS, Gansky SA, Marshall GW, Marshall SJ.  Effect of hydration variability on hybrid layer properties of a self-etching vs. an acid-etching system. Biomaterials 2005 26:1011-1018.
Balooch M, Balooch G, Habelitz S, Marshall SJ, Marshall GW. Intrafibrillar demineralization study of single human dentin collagen fibrils.  Mat Res Soc Symp Proc. 2004 823:W6.1.1-6.  
Foppiano S, Marshall SJ, Marshall GW, Saiz E, Tomsia AP. The influence of novel bioactive glasses on in vitro osteoblast behavior.  J Biomed Mater Res. 2004 71A:242-249. 
Habelitz S, Kullar A, Marshall SJ, DenBesten PK, Balooch M, Marshall GW, Li W. Amerlogenin-guided crystal growth on fluoroapatite glass- ceramics. J Dent Res  2004 83:698-702. 
Ho SP, Balooch M, Matshall SJ, Marshall GW. Local Properties of a functionally graded interphase between cementum and dentin. J Biomed Mater Res 2004 70A:480-489. 
Oliveira SSA, Marshall SJ, Habelitz S, Gansky SA, Wilson RS, Marshall GW. The effect of a self-etching primer on the continuous demineralization of dentin. Eur J Oral Sci 2004 112:376-383. 
Balooch G, Marshall GW, Marshall SJ, Warren OL, Asif SAS, Balooch M. Evaluation of a new modulus mapping technique to investigate microstructural features of human teeth. J Biomech 2004 37:1223-1232. 
Ho SP, Goodis H, Balooch M, Nonomura G, Marshall SJ, Marshall GW. The effect of sample preparation technique on determination of structure and nanomechanical properties of human cementum hard tissue. Biomaterials 2004 25:4847-4857.  
Schulze KA, Balooch M, Balooch G, Marshall GW, Marshall SJ. A Micro Raman Spectroscopic Investigation of the Dentin-Enamel Junction and Cementum-Dentin Junction.  J Biomed Mater Res 2004 69A: 286-293. 
Kinney JH, Gladden JR, Marshall GW, Marshall SJ, So JH, Maynard JD. Resonant ultrasound spectroscopy measurements of the elastic constants of human dentin J Biomech  2004 37:  437-441. 
Ho SP, Balooch M, Goodis HE, Marshall GW, Marshall SJ. Ultrastructure and nanomechanical properties of cementum dentin junction.
J Biomed Mater Res  2004  68A:343-351. 
Kinney JH, Habelitz S, Marshall SJ, Marshall GW. The importance of intrafibrillar mineralization of collagen on the mechanical properties of dentin. J Dent Res 2003 82: 957-961. 
Marshall SJ, Balooch M, Habelitz S, Balooch G, Gallagher R, Marshall GW. The dentin-enamel junction-a natural, multilevel interface. J European Ceram Soc 2003 23: 2897-2904. 
Oliveira SS, Pugach MK, Hilton JF, Watanabe LG, Marshall SJ, Marshall GW. The influence of the dentin smear layer on adhesion: a self-etching primer vs. a total-etch system. Dent Mater. 2003 19:758-767. 
Habelitz S, Ford D, Marshall SJ, DenBesten PK, Balooch M, Marshall GW, Li W. Amerogenin induces biomimetic mineralization at specific pH. Mat Sci Res Symp Proc. 2003 774:07.8.1-O7.8.6.  
Marshall GW , Marshall SJ, Balooch M, Kinney JH. Evaluating Demineralization and Mechanical Properties of Human Dentin with AFM. Chapter 11 in Methods in Mol Biol 2004  242 : 141-159.
Schulze KA, Tinschert J, Marshall SJ, Marshall GW. Effect of aging on the color and surface quality of composites (in German). Deutscher Zahnarzte Zeitschrift   58:266-271, 2003. 
Marshall SJ, Balooch M, Habelitz S, Balooch G, Marshall GW. Dentin-Enamel Junction (DEJ)-Biomimetic Model for Material Tissue Interfaces. Transactions Acad Dent Mater 17:21-32, 2003. 
Schulze KA, Tinschert J, Marshall SJ, Marshall GW. Spectroscopic Analysis of Polymer-Ceramic Dental Composites after Acellerated Aging. Int J Prosthodont 16:355-361, 2003. 
Schulze KA, Marshall SJ, Gansky SA , Marshall GW. Color stability and hardness in dental composites after accelerated aging. Dent Mater 19: 612-619, 2003. 
Zheng L, Hilton JF, Habelitz S, Marshall SJ, Marshall GW. Dentin caries activity status related to hardness and elasticity. Eur J  Oral Sci 111 (3), 243-252, 2003. 
Kinney JH, Marshall SJ, Marshall GW. The Mechanical Properties of Human Dentin: A Critical Review and Re-Evaluation of the Dental Literature. Crit Rev Oral Biol Med  14:13-29, 2003.  
Gallagher RR, Demos SG, Balooch M, Marshall GW, Marshall SJ. Optical spectroscopy and imaging of the dentin-enamel junction in human third molars. J Biomed Mater Res.  64A:372-377, 2003.  
Habelitz S, Balooch M, Marshall SJ, Balooch G, Marshall GW. In Situ Atomic Force Microscopy of Partially Demineralized Human Dentin Collagen Fibrils. J Struct Biol 138: 227-236, 2002.
Staninec M, Marshall GW, Hilton JF, Pashley DH, Gansky SA, Marshall SJ, Kinney JH. Ultimate Tensile Strength of  Dentin: Evidence for a Damage Mechanics Approach to Dentin Failure. J Biomed Mater Res (Appl Biomat) 63:342-345, 2002.

Oliveria SSA, Marshall SJ , Hilton JF, Marshall GW. Etching kinetics of a self-etching  primer.  Biomaterials 23:4105-4112, 2002.  
Saiz E, Goldman M, Gomez-Vega HM, Tomsia AP, Marshall GW, Marshall SJ. In vitro behavior of silicate glass coatings on Ti6Al4V. Biomaterials 23:3749-56, 2002.
Habelitz S, Marshall GW, Balloch M, Marshall SJ. Nanoindentaion and storage of teeth. J Biomechanics  35:995-998, 2002. 
Liu S-C, Marshall SJ, Tomar S, Marshall GW. The Prevalence of Microcanals in Maxillary Anterior Primary Teeth. Pediatr Dent 22:318-320, 2000.
Marshall GW, Balooch M, Gallagher RR, Gansky SA, Marshall SJ. Mechanical Properties of the Dentinoenamel Junction: AFM Studies of Nanohardness, Elastic Modulus and Fracture. J Biomed Mater Res 54:87-95, 2001.
Habelitz S, Marshall SJ, Marshall GW, Balooch M. Mechanical Properties of Human Dental Enamel on the nanometer scale. Arch Oral Biol 46 173-183, 2001.
Marshall GW, Chang JY, Gansky SA, Marshall SJ. Demineralization of Caries-affected Transparent Dentin by Citric Acid: an Atomic Force Microscopy Study. Dent Mater 17:45-52, 2001.
Kinney JH, Marshall GW, Marshall SJ, Haupt DL. Three-Dimensional Imaging of Large Compressive Deformations in Elastomeric Foams. J Appl Polymer Science 80:1746-1755, 2001.
Saeki K, Marshall SJ, Gansky SA, Marshall GW. Etching Characteristics of Dentin: Effect of ferric chloride in citric acid. J Oral Rehab 28:301-308, 2001.
Balooch M, Demos SG, Kinney JH,Marshall GW, Balooch G, Marshall SJ.Local Mechanical and Optical Properties of Normal and Transparent Root Dentin. J Mat Sci: Mater in Med 12:507-514, 2001.
Kinney JH, Oliveria J, Haupt DL Marshall GW, Marshall SJ. The spatial arrangement of tubules in human dentin. J Mat Sci: Mater in Med 12:743-751, 2001.
Kinney JH, Pople JA, Marshall GW, Marshall SJ. Collagen orientation and crystallite size in human dentin: A small angle x-ray scattering study. Calcified Tissue int 69:31-37, 2001.
Kinney JH, Pople JA, Driessen CH, Breunig TM,  Marshall GW, Marshall SJ. Intrafibrillar mineral may be absent in Dentinogenesis Imperfecta Type II (DI-II). J Dent Res 80:1555-1559, 2001.
Marshall GW, Yucel N, Balooch M, Kinney JH, Habelitz S, Marshall SJ. Sodium hypocholorite alterations of dentin and dentin collagen.  Surface Science 491:444-455, 2001.
Marshall GW, Habelitz S, Gallagher R, Balooch M, Balooch G, Marshall SJ. Nanomechanical  properties of hydrated carious human dentin. J Dent Res 80: 1768-1771,  2001.
Habelitz S, Marshall SJ, Marshall GW, Balooch M. The Functional Width of the DEJ Determined by AFM-based Nanoscratching. J Struct Biol 135:244-301, 2001.
Habelitz S, Balooch M, Marshall GW, Breunig TM, Marshall SJ. AFM-based Nanomechanical Properties and Storage of  Dentin and Enamel. Mater Res Soc Symp Proc 676: Y.3.27.1-Y.3.27.5, 2001.
Marshall GW, Chang YJ, Saeki K, Gansky SA, Marshall SJ. Citric Acid Etching of Cervical Sclerotic Dentin Lesions: An AFM Study. J Biomed Mater Res 49:338-344, 2000.
Gomez-Vega JM, Saiz E, Tomsia AP, Marshall GW, Marshall SJ. Bioactive glass coatings with hydroxyapatite and Bioglass particles on Ti-based implants. 1.Processing. Biomaterials 21:105-111, 2000.
Hosoya Y, Marshall SJ, Watanabe LG, Marshall GW . Microhardness of Carious Deciduous Dentin. Op Dent 25:81-89, 2000
Gomez-Vega JM, Saiz E, Tomsia AP, Oku T, Suganumu K, Marshall GW, Marshall SJ. Novel Bioactive functionally graded coatings on Ti6Al4V Adv Mater 12:894-898, 2000. Marshall GW, Wu-Magidi I-C, Watanabe LG, Inai N, Balooch M, Kinney JH, Marshall SJ. Effect of Citric Acid Concentration on Dentin Demineralization, Dehydration and Rehydration: an AFM Study. J Biomed Mater Res. 42: 500-507, 1998.
Gomez-Vega JM, Saiz E, Tomsia AP, Marshall GW, Marshall SJ. A Multilayer Approach to Fabricate Bioactive Glass Coatings on Ti Alloys. Biomedical Materials-Drug Delivery, Implants and Tissue Engineering, MRS. Symp. Proc.,550,. 349-354, 1999.
Rosales JI, Marshall GW, Marshall SJ, Watanabe LG, Toledano M, Cabrerizo MA, Osorio R. Acid Etching and Hydration Influence on Dentin Roughness and Wetatability. J Dent Res 78: 1554-1559, 1999.
Kinney JH, Balooch M, Marshall GW, Marshall SJ. A Micromechanics Model of the Elastic Properties of Human Dentin. Arch oral Biol 44:813-822, 1999.
Marshall GW, Saeki K, Gansky SA, Marshall SJ. AFM Study of Citric Acid-Ferric Chloride Etching Characteristics of Dentin. Am J Dent 12:271-276, 1999.
Sumikawa DA, Marshall GW, Gee L, Marshall SJ. Microstructure of Primary Dentin. Pediatr Dent 21:439-444, 1999.
Marshall SJ, Balooch M, Breunig T, Kinney JH, Tomsia AT, Inai N, Watanabe LG, Wu-Magedi IC, Marshall GW. Human Dentin and the Dentin-Resin Adhesive Interface. Acta Mater 46: 2529-2539, 1998.
Balooch M, Wu-Magidi, IC, Lundkvist AS, Balazs, Marshall SJ, Marshall GW, WJ Seikhaus, Kinney JH. Viscolelastic Properties of Demineralized Human Dentin in Water with Atomic Force Microscopy (AFM)-Based Indentation, J. Biomed Mater Res. 40:539-544, 1998.
Inai N, Kanemura N, Tagami J, Watanabe LG, Marshall SJ, Marshall GW. Adhesion between Collagen Depleted Dentin and Dentin Adhesives. Am J Dent 11:123-127, 1998.  
Marshall GW, Marshall SJ, Kinney JH, Balooch M. The Dentin Substrate: Structure and Properties Related to Bonding. J Dent 25:441-458, 1997.
Letzel H, Van't Hof MA, Marshall GW, Marshall SJ. The Influence of the Amalgam Alloy on the Survival of Amalgam Restorations: A Secondary Analysis of Multiple Controlled Clinical Trials. J Dent Res 76: 1787-1798, 1997.
Goodis HE, White JM. Marshall GW, Yee K, Fuller N, Gee L, Marshall SJ, Effects of Nd:and Ho:YAG Lasers on Dentin Flow and Pulp Chamber Temperature, In Vitro. Arch oral Biol 42:845-854, 1997.
Kinney JH, Balooch M, Marshall SJ, Marshall GW, Weihs TP. Atomic Force Microscope Measurements of the Hardness and Elasticity of Peritubular and Intertubular Dentin. J Biomech Eng 118: 133-135, 1996.
Kinney JH, Balooch M, Marshall SJ, Marshall GW, Weihs, TP. Hardness and Young's Modulus of Human Peritubular and Intertubular Dentine. Arch Oral Biol 41:9-13, 1996.
Watanabe L, Marshall GW, Marshall SJ. Dentin Shear Strength: Effects of tubule orientation and intratooth location. Dent Mater 12:109-115, 1996.
Kinney JH, Haupt DL, Balooch M, White JM, Bell WL, Marshall SJ, Marshall GW. The Threshold Effects of Nd and Ho:YAG Laser-Induced Surface Modification on Demineralization of Dentin Surfaces. J Dent Res 75: 1388-1395, 1996.
Strawn SE, White JM, Marshall GW, Gee L, Goodis HE, Marshall SJ. Changes in optical properties and surface chemistry of dentin after short term storage. J Dent 24:417-423, 1996. Kinney JH, Marshall GW, Marshall SJ. Three dimensional mapping of mineral densities in carious dentin: theory and method. Scann Microsc 8:197-205, 1994.
Goodis H, White J, Yee B, Marshall S, Marshall G. Sterilization of root canal spaces using an Nd:YAG laser, In Vitro. SPIE 2394:154-159, 1995.
Kinney JH, Balooch M, Haupt DL, Marshall SJ, Marshall GW. Mineral distribution and dimensional changes in human dentin during demineralization. J Dent Res 74:1179-1184, 1995.
Marshall GW, Balooch M, Kinney JH, Marshall SJ. Atomic force microscopy of conditioning agents on dentin. J Biomed Mater Res 29:1381-1387, 1995. Marshall SJ, Marshall GW Jr, Kinney JH, Balooch M. Dental Restorative Material-Tooth Interfaces. Scripta Metallurgica et Materialia 31:983-988, 1994.
Kinney JH, Haupt DL, Nichols MC, Breunig TM, Marshall GW Jr, Marshall SJ. The X-Ray Tomographic Microscope: Three-Dimensional Perspectives of Evolving Microstructures. Nuclear Instruments & Methods A 347:480-486, 1994.
Goodis HE, White JM, Marshall SJ, Marshall Jr GW. Bacterial reduction and dentin microhardness after treatment by a pulsed fiber optic delivered Nd:YAG laser. SPIE 2128:431-438, 1994.
White JM, Goodis HE, Marshall SJ, Marshall GW. Sterilization of teeth by gamma radiation. J Dent Res 73:1560-1567, 1994.
Goodis HE, White JM, Marshall SJ, Marshall GW. Measurement of fluid flow through laser treated dentine. Arch Oral Biol 39 Suppl:128S, 1994.
Goodis HE, Marshall GW, White JM, Gee L, Hornberger D, Marshall SJ. Storage Effects on Dentin Permeability and Shear Bond Strengths. Dent Mater 9:79-84, 1993.
Kinney JH, Balooch M, Marshall GW, Marshall SJ. Atomic Force Microscope Study of Dimensional Changes in Dentine During Drying. Arch Oral Biol 38:1003-1007, 1993.
White JM, Goodis HE, Marshall GW, Marshall SJ. Identification of the physical modification threshold of dentin induced by Neodymium and Holmium YAG lasers using scanning electron microscopy. Scann Microsc 7:239-246, 1993.
Marshall GW, Balooch M, Tench R, Kinney JH, Marshall SJ. Atomic Force Microscopy of Acid Effects on Dentin. Dent Mater 9:265-268, 1993
Goodis HE, White JM, Marshall SJ, Marshall GW. Scanning electron microscopic examination of intracanal wall dentin: hand vs laser treatment. Scann Microsc 7:979-987, 1993. 
Marshall GW, McCoy DD, Kinney JH, Letzel H, Marshall SJ. Microstructural Changes in retrieved amalgam restorations. Cells and Mater 2:29-36, 1992.
Marshall SJ, Marshall GW. Dental amalgam: the materials. Adv in Dent Res 6:29-36, 1992.
Marshall SJ, Marshall GW, Letzel H. Gamma-1 to Beta-1 phase transformation in retrieved clinical amalgam restorations. Dent Mater 8:162-166, 1992.
Goodis HE, White JM, Marshall SJ, Marshall GW, Moskowitz E. Root canal preparation in endodontics: conventional vs laser methods. Proceedings SPIE 1643: 412-422, 1992.
Tsunekawa M, Setcos JC, Usami Y, Iwaku M, Marshall SJ. A new light-activated adhesion composite: shear bond strength and microleakage. Dent Mater 8:234-237, 1992.
Binon PP, Weir DJ, Marshall SJ. Surface analysis of an original Br nemark implant and three related clones. Int J Oral Maxillofac Implants 7:168-175, 1992. Bagby M, Marshall SJ, Marshall GW. Metal ceramic compatibility: A review of the literature. J Prosthet Dent 63:21-25, 1990.
Bagby M, Marshall SJ, Marshall GW. Effects of porcelain application procedures on two noble alloys. J Appl Biomaterials 1:31-37, 1990.
Marshall GW, Staninec M, Torii Y, Marshall SJ. Comparison of backscattered SEM and microradiography of secondary caries. Scanning Microscopy 3:1043-1050, 1989.
Marshall GW, Marshall SJ, Letzel H. Mercury content of amalgam restorations. Gen Dent 37:473-477, 1989.
Letzel H, Van't Hof MA, Vrijhoef MMA, Marshall GW, Marshall SJ. A controlled clinical study of amalgam restorations: survival, failures, and causes of failure. Dent Mater 5:115-121, 1989.
Curtis DA, Eggleston TA, Watanabe LG, Marshall SJ. Shear bond strength of visible-light cured resin relative to heat cured resin. Dent Mater 5:314-318, 1989.
Letzel H, Van't Hof MA, Vrijhoef MMA, Marshall GW, Marshall SJ. Failure, survival, and reasons for replacement of amalgam restorations in quality evaluation of dental restorations. K. Anusavice, Ed., Chicago, Quintessense Pub Co Inc., 83-92, 1989.
Marshall GW, Staninec M, Torii Y, Marshall SJ. Comparison of backscattered SEM and microradiography of secondary caries. Scanning Micros 3:1043-1050, 1989.  
Marshall GW, Marshall SJ, Bayne SC. Restorative dental materials: scanning electron microscopy and x-ray microanalysis. Scanning Microscopy 2:2007-2028, 1988.