Academic Appointments


Honors & Awards


  • Outstanding contribution to engineering, PVP Division of ASME
  • Certificate of Recognition for Bone tissue analyzer and method, NASA (1987)
  • Claude Pepper Award, NIH (1988)
  • Humboldt Senior Fellowship Award, Germany (1994)
  • Honorary Ph.D., Zaporozhye State University, Ukraine (1997)
  • Eminent Academician, Ukrainian Academy of Higher Education (1998)
  • Warner T. Koiter Medal, ASME (1999)
  • Academy of Distinguished Graduates, Department of Mechanical Engineering, Texas A&M University (October 2001)

Boards, Advisory Committees, Professional Organizations


  • Member, National Academy of Engineering (1995 - Present)

Professional Education


  • BS, Texas A&M University, Mechanical Engineering (1956)
  • PhD, Stanford University (1960)

Patents


  • Charles Steele. "United StatesBone Stiffness Measurement System", Leland Stanford Junior University, Feb 2, 1986

2016-17 Courses


All Publications


  • Unraveling the mystery of hearing in gerbil and other rodents with an arch-beam model of the basilar membrane SCIENTIFIC REPORTS Kapuria, S., Steele, C. R., Puria, S. 2017; 7

    Abstract

    The mammalian basilar membrane (BM) consists of two collagen-fiber layers responsible for the frequency-to-place tonotopic mapping in the cochlea, which together form a flat beam over at least part of the BM width. The mechanics of hearing in rodents such as gerbil pose a challenge to our understanding of the cochlea, however, because for gerbil the two layers separate to form a pronounced arch over the remaining BM width. Moreover, the thickness and total width normally thought to determine the local stiffness, and tonotopic mapping in turn, change little along the cochlear length. A nonlinear analysis of a newly developed model, incorporating flat upper and arched lower fiber layers connected by ground substance, explains the initial plateau and subsequent quadratic increase found in measured stiffness vs. deflection curves under point loading, while for pressure loading the model accurately predicts the tonotopic mapping. The model also has applicability to understanding cochlear development and to interpreting evolutionary changes in mammalian hearing.

    View details for DOI 10.1038/s41598-017-00114-x

    View details for Web of Science ID 000396982200005

    View details for PubMedID 28331175

  • Cochlear Outer-Hair-Cell Power Generation and Viscous Fluid Loss SCIENTIFIC REPORTS Wang, Y., Steele, C. R., Puria, S. 2016; 6

    View details for DOI 10.1038/srep19475

    View details for Web of Science ID 000368776000001

  • Human Stapedial Annular Ligament Mechanical and Geometrical Property Analysis using a Bi-layer Tapered Beam Model INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING Baek, J. D., Steele, C. R., Yoon, Y. 2015; 16 (7): 1623-1630
  • Cytoarchitecture of the mouse organ of corti from base to apex, determined using in situ two-photon imaging. Journal of the Association for Research in Otolaryngology : JARO Soons, J. A., Ricci, A. J., Steele, C. R., Puria, S. 2015; 16 (1): 47-66

    Abstract

    The cells in the organ of Corti are highly organized, with a precise 3D microstructure hypothesized to be important for cochlear function. Here we provide quantitative data on the mouse organ of Corti cytoarchitecture, as determined using a new technique that combines the imaging capabilities of two-photon microscopy with the autofluorescent cell membranes of the genetically modified mTmG mouse. This combination allowed us to perform in situ imaging on freshly excised tissue, thus minimizing any physical distortions to the tissue that extraction from the cochlea and chemical fixation and staining might have caused. 3D image stacks of the organ of Corti were obtained from base to apex in the cochlear duct, from which 3D lengths and relative angles for inner and outer hair cells, Deiters' cells, phalangeal processes, and inner and outer pillars were measured. In addition, intercellular distances, diameters, and stereocilia shapes were obtained. An important feature of this study is the quantitative reporting of the longitudinal tilts of the outer hair cells towards the base of the cochlea, the tilt of phalangeal processes towards the apex, and Deiters' cells that collectively form a Y-shaped building block that is thought to give rise to the lattice-like organization of the organ of Corti. The variations of this Y-shaped element along the cochlear duct and between the rows of outer hair cells are shown with the third row morphologically different from the other rows, and their potential importance for the cochlear amplifier is discussed.

    View details for DOI 10.1007/s10162-014-0497-1

    View details for PubMedID 25348579

    View details for PubMedCentralID PMC4310856

  • Cytoarchitecture of the mouse organ of corti from base to apex, determined using in situ two-photon imaging. Journal of the Association for Research in Otolaryngology : JARO Soons, J. A., Ricci, A. J., Steele, C. R., Puria, S. 2015; 16 (1): 47-66

    View details for DOI 10.1007/s10162-014-0497-1

    View details for PubMedID 25348579

  • The importance of the hook region of the cochlea for bone-conduction hearing. Biophysical journal Kim, N., Steele, C. R., Puria, S. 2014; 107 (1): 233-241

    Abstract

    For the most part, the coiled shape of the cochlea has been shown to have only minor importance for air-conducted hearing. It is hypothesized, however, that this coiled shape may play a more significant role for the bone-conducted (BC) route of hearing, through inertial forces exerted by the middle ear and cochlear fluid, and that this can be tested by comparing the results of applying BC stimuli in a variety of different directions. A three-dimensional finite element model of a human middle ear coupled to the inner ear was formulated. BC excitations were simulated by applying rigid-body vibrations normal to the surface of the basilar membrane (BM) at 0.8 (d(1)), 5.8 (d(2)), 15.6 (d(3)), and 33.1 (d(4)) mm from the base of the cochlea, such that relative motions of the fluid within the cochlea produced excitations of the BM. The vibrational direction normal to the BM surface at the base of the cochlea (d(1)) produced the highest BM velocity response across all tested frequencies-higher than an excitation direction normal to the BM surface at the nonbasal locations (d(2)-d(4)), even when the stimulus frequency matched the best frequency for each location. The basal part of the human cochlea features a well-developed hook region, colocated with the cochlear vestibule, that features the largest difference in fluid volume between the scala vestibuli (SV) and scala tympani (ST) found in the cochlea. The proximity of the hook region to the oval and round windows, combined with it having the biggest fluid-volume difference between the SV and ST, is thought to result in a maximization of the pressure difference between the SV and ST for BC stimuli normal to the BM in this region, and consequently a maximization of the resulting BM velocity.

    View details for DOI 10.1016/j.bpj.2014.04.052

    View details for PubMedID 24988357

    View details for PubMedCentralID PMC4119269

  • The Importance of the Hook Region of the Cochlea for Bone-Conduction Hearing BIOPHYSICAL JOURNAL Kim, N., Steele, C. R., Puria, S. 2014; 107 (1): 233-241
  • Acoustics-structure interactions in the human middle ear produce variety of motion modes at the malleus-incus complex. journal of the Acoustical Society of America Cai, H., Jackson, R. P., Steele, C. R., Puria, S. 2013; 134 (5): 4228-?

    Abstract

    We developed a 3D finite-element model to simulate the dynamics of the human middle ear, using COMSOL Multiphysics software to solve the resulting acoustics-structure interaction problem. We validated the model by comparing numerical results with experimental data measured in the ear canal, on the tympanic membrane (TM), at the umbo, and at the stapes footplate. The results show that at low frequencies (up to 500 Hz), the conventionally accepted hinge-like motion of the malleus-incus complex dominates the response, with the angle between the rotational axes of the malleus and incus staying below about 5 degrees. However, above 5 kHz, this angle becomes significantly larger, indicating that the malleus and incus rotate about different axes. Near the upper frequency limit of 20 kHz, the angle between the rotational axes of the malleus and incus approaches 90 degrees as the malleus adopts a lower-inertia twisting-like rotation about its first principal axis. The model is also used to explore the effects, on ossicular motion and overall pressure transfer from the ear canal to the cochlea, of alterations to the mechanical properties of the TM, to the flexibility of the malleus-incus joint, and to the mass of the ossicles. [Funded by NIDCD/NIH.].

    View details for DOI 10.1121/1.4831529

    View details for PubMedID 24181861

  • Finite element model of feed-forward/feed-backward amplification in the mouse cochlea. journal of the Acoustical Society of America Soons, J., Puria, S., Steele, C. R. 2013; 134 (5): 4063-?

    Abstract

    Thousands of hair cells in the organ of Corti, situated along the basilar membrane (BM), detect displacements due to sound input. For low input sounds, these displacements are amplified by active outer hair cells (OHCs). A proposed theory is the feed-forward/feed-backward mechanism for the OHC amplification where an expanding hair cell gives a forward push through the Deiters Cells and a backward pull on the BM through the Phalangeal process. Previously this was implemented mathematically using WKB theory (Yoon et al. 2011, Biophys. J.). In the present work, we explicitly modeled this as a Y-shaped arrangement of the OHC-DeitersCell-PhallangealProcess to form a building block using beam elements in a finite element formulation. These Y-shaped blocks were chained together to construct a single-row organ-of-Corti model from the base to apex, coupled to the BM and scalae fluid, of a mouse cochlea. The OHC force is proportional to the shear on the BM. For a 10 kHz stapes input tone, the passive BM reaches a peak gain of about 26 dB. For the active case the BM gain increases to 58 dB and shifts apically by about 0.6 mm. These results are consistent with physiological measurements in several other living animals.

    View details for DOI 10.1121/1.4830831

    View details for PubMedID 24181237

  • Superior-semicircular-canal dehiscence: Effects of location, shape, and size on sound conduction. Hearing research Kim, N., Steele, C. R., Puria, S. 2013; 301: 72-84

    Abstract

    The effects of a superior-semicircular-canal (SSC) dehiscence (SSCD) on hearing sensitivity via the air-conduction (AC) and bone-conduction (BC) pathways were investigated using a three-dimensional finite-element (FE) model of a human middle ear coupled to the inner ear. Dehiscences were modeled by removing a section of the outer bony wall of the SSC and applying a zero-pressure condition to the fluid surface thus exposed. At each frequency, the basilar-membrane velocity, vBM, was separately calculated for AC and BC stimulation, under both pre- and post-dehiscence conditions. Hearing loss was calculated as the difference in the maximum magnitudes of vBM between the pre- and post-dehiscence conditions representing a change in hearing threshold. In this study, BC excitations were simulated by applying rigid-body vibrations to the model along the directions of the (arbitrarily defined) x, y, and z axes of the model. Simulation results are consistent with previous clinical measurements on patients with an SSCD and with results from earlier lumped-element electrical-circuit modeling studies, with the dehiscence decreasing the hearing threshold (i.e., increasing vBM) by about 35 dB for BC excitation at low frequencies, while for AC excitation the dehiscence increases the hearing threshold (i.e., decreases vBM) by about 15 dB. A new finding from this study is that the initial width (defined as the width of the edge of the dehiscence where the flow of the fluid-motion wave from the oval window meets it for the first time) on the vestibular side of the dehiscence has more of an effect on vBM than the area of the dehiscence. Analyses of dehiscence effects using the FE model further predict that changing the direction of the BC excitation should have an effect on vBM, with vBM being about 20 dB lower due to BC excitation parallel to the longitudinal direction of the BM in the hook region (the x direction) as compared to excitations in other directions (y and z). BC excitation in the x direction and with a 'center' dehiscence located midway along the length of the SSC causes a reduction in the anti-symmetric component of the fluid pressure across the BM, as compared to the other directions of BC excitation, which results in a decrease in vBM at high frequencies. This article is part of a Special Issue entitled "MEMRO 2012".

    View details for DOI 10.1016/j.heares.2013.03.008

    View details for PubMedID 23562774

  • Rationale, design and clinical performance of the mechanical response tissue analyser: a non-invasive technology for measurement of long bone bending stiffness. Journal of medical engineering & technology Miller, L. E., Ramp, W. K., Steele, C. R., Nickols-Richardson, S. M., Herbert, W. G. 2013; 37 (2): 144-149

    Abstract

    Prediction of osteoporotic fractures is currently an imperfect science and new tools are desperately needed to identify at-risk patients at an earlier stage in the disease process. The mechanical response tissue analyser (MRTA) is a novel, non-invasive, radiation-free device that measures the bending stiffness of long bones in vivo, an indicator of a bone's ability to resist deformation under a given load and a strong predictor of long bone structural integrity and strength. Bone bending stiffness measured with the MRTA has been consistently shown to be a stronger predictor of post-mortem and ex vivo bone breaking strength compared to bone mineral measured with dual-energy X-ray absorptiometry. Bone bending stiffness measured with MRTA also decreases with advanced age and disease states and increases with chronic physical activity, independent of bone mineral changes. The MRTA measures different parameters than DXA (bone quality vs bone mineral content and density) and may be a more robust tool for identifying those at risk for fracture. Research initiatives focused on improving long-term repeatability and optimizing the signal-to-noise ratio of the measurement are currently underway to further advance the clinical usefulness of this technology.

    View details for DOI 10.3109/03091902.2012.753128

    View details for PubMedID 23360197

  • Von Bekesy and cochlear mechanics HEARING RESEARCH Olson, E. S., Duifhuis, H., Steele, C. R. 2012; 293 (1-2): 31-43

    Abstract

    Georg Békésy laid the foundation for cochlear mechanics, foremost by demonstrating the traveling wave that is the substrate for mammalian cochlear mechanical processing. He made mechanical measurements and physical models in order to understand that fundamental cochlear response. In this tribute to Békésy we make a bridge between modern traveling wave observations and those of Békésy, discuss the mechanical properties and measurements that he considered to be so important, and touch on the range of computational traveling wave models.

    View details for DOI 10.1016/j.heares.2012.04.017

    View details for Web of Science ID 000314331500005

    View details for PubMedID 22633943

  • Biophysical Mechanisms Underlying Outer Hair Cell Loss Associated with a Shortened Tectorial Membrane JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY Liu, C. C., Gao, S. S., Yuan, T., Steele, C., Puria, S., Oghalai, J. S. 2011; 12 (5): 577-594

    Abstract

    The tectorial membrane (TM) connects to the stereociliary bundles of outer hair cells (OHCs). Humans with an autosomal dominant C1509G mutation in alpha-tectorin, a protein constituent of the TM, are born with a partial hearing loss that worsens over time. The Tecta(C1509/+) transgenic mouse with the same point mutation has partial hearing loss secondary to a shortened TM that only contacts the first row of OHCs. As well, Tecta(C1509G/+) mice have increased expression of the OHC electromotility protein, prestin. We sought to determine whether these changes impact OHC survival. Distortion product otoacoustic emission thresholds in a quiet environment did not change to 6 months of age. However, noise exposure produced acute threshold shifts that fully recovered in Tecta (+/+) mice but only partially recovered in Tecta(C1509G/+) mice. While Tecta(+/+) mice lost OHCs primarily at the base and within all three rows, Tecta(C1509G/+) mice lost most of their OHCs in a more apical region of the cochlea and nearly completely within the first row. In order to estimate the impact of a shorter TM on the forces faced by the stereocilia within the first OHC row, both the wild type and the heterozygous conditions were simulated in a computational model. These analyses predicted that the shear force on the stereocilia is ~50% higher in the heterozygous condition. We then measured electrically induced movements of the reticular lamina in situ and found that while they decreased to the noise floor in prestin null mice, they were increased by 4.58 dB in Tecta(C1509G/+) mice compared to Tecta(+/+) mice. The increased movements were associated with a fourfold increase in OHC death as measured by vital dye staining. Together, these findings indicate that uncoupling the TM from some OHCs leads to partial hearing loss and places the remaining coupled OHCs at higher risk. Both the mechanics of the malformed TM and the increased prestin-related movements of the organ of Corti contribute to this higher risk profile.

    View details for DOI 10.1007/s10162-011-0269-0

    View details for Web of Science ID 000294909800004

    View details for PubMedID 21567249

  • Timoshenko Modeling of the Pipa String ACTA ACUSTICA UNITED WITH ACUSTICA Chin, S. L., Steele, C. 2011; 97 (2): 315-324

    View details for DOI 10.3813/AAA.918411

    View details for Web of Science ID 000288130700015

  • Feed-Forward and Feed-Backward Amplification Model from Cochlear Cytoarchitecture: An Interspecies Comparison BIOPHYSICAL JOURNAL Yoon, Y., Steele, C. R., Puria, S. 2011; 100 (1): 1-10

    Abstract

    The high sensitivity and wide bandwidth of mammalian hearing are thought to derive from an active process involving the somatic and hair-bundle motility of the thousands of outer hair cells uniquely found in mammalian cochleae. To better understand this, a biophysical three-dimensional cochlear fluid model was developed for gerbil, chinchilla, cat, and human, featuring an active "push-pull" cochlear amplifier mechanism based on the cytoarchitecture of the organ of Corti and using the time-averaged Lagrangian method. Cochlear responses are simulated and compared with in vivo physiological measurements for the basilar membrane (BM) velocity, V(BM), frequency tuning of the BM vibration, and Q₁₀ values representing the sharpness of the cochlear tuning curves. The V(BM) simulation results for gerbil and chinchilla are consistent with in vivo cochlea measurements. Simulated mechanical tuning curves based on maintaining a constant V(BM) value agree with neural-tuning threshold measurements better than those based on a constant displacement value, which implies that the inner hair cells are more sensitive to V(BM) than to BM displacement. The Q₁₀ values of the V(BM) tuning curve agree well with those of cochlear neurons across species, and appear to be related in part to the width of the basilar membrane.

    View details for DOI 10.1016/j.bpj.2010.11.039

    View details for Web of Science ID 000286126600002

    View details for PubMedID 21190651

    View details for PubMedCentralID PMC3010833

  • Biophysical Mechanisms Underlying Hearing Loss Associated with a Shortened Tectorial Membrane 11th International Workshop on the Mechanics of Hearing Oghalai, J. S., Xia, A., Liu, C. C., Gao, S. S., Applegate, B. E., Puria, S., Rousso, I., Steele, C. AMER INST PHYSICS. 2011

    View details for DOI 10.1063/1.3658070

    View details for Web of Science ID 000301945200019

  • Mechanics of the Unusual Basilar Membrane in Gerbil 11th International Workshop on the Mechanics of Hearing Kapuria, S., Steele, C. R., Puria, S. AMER INST PHYSICS. 2011

    View details for DOI 10.1063/1.3658107

    View details for Web of Science ID 000301945200056

  • Elastostatic Analysis of the Membrane Tenting Deformation of Inner-Ear Stereocilia 11th International Workshop on the Mechanics of Hearing Kim, J., Pinsky, P. M., Ricci, A. J., Puria, S., Steele, C. R. AMER INST PHYSICS. 2011

    View details for DOI 10.1063/1.3658059

    View details for Web of Science ID 000301945200008

  • Bone Conduction Hearing: Three-Dimensional Finite Element Model of the Human Middle and Inner Ear 11th International Workshop on the Mechanics of Hearing Kim, N., Homma, K., Puria, S., Steele, C. R. AMER INST PHYSICS. 2011

    View details for DOI 10.1063/1.3658108

    View details for Web of Science ID 000301945200057

  • Stereotype Threat Affects Financial Decision Making PSYCHOLOGICAL SCIENCE Carr, P. B., Steele, C. M. 2010; 21 (10): 1411-1416

    Abstract

    The research presented in this article provides the first evidence that one's decision making can be influenced by concerns about stereotypes and the devaluation of one's identity. Many studies document gender differences in decision making, and often attribute these differences to innate and stable factors, such as biological and hormonal differences. In three studies, we found that stereotype threat affected decision making and led to gender differences in loss-aversion and risk-aversion behaviors. In Study 1, women subjected to stereotype threat in academic and business settings were more loss averse than both men and women who were not facing the threat of being viewed in light of negative stereotypes. We found no gender differences in loss-aversion behavior in the absence of stereotype threat. In Studies 2a and 2b, we found the same pattern of effects for risk-aversion behavior that we had observed for loss-aversion behavior. In addition, in Study 2b, ego depletion mediated the effects of stereotype threat on women's decision making. These results suggest that individuals' decision making can be influenced by stereotype concerns.

    View details for DOI 10.1177/0956797610384146

    View details for Web of Science ID 000285455600009

    View details for PubMedID 20855899

  • MEMRO 2009-Middle-ear science and technology HEARING RESEARCH Puria, S., Goode, R. L., Steele, C. 2010; 263 (1-2): 1-2

    View details for DOI 10.1016/j.heares.2010.03.079

    View details for Web of Science ID 000278583700001

    View details for PubMedID 20347945

  • Tympanic-membrane and malleus-incus-complex co-adaptations for high-frequency hearing in mammals 5th International Symposium on Middle Ear Mechanics in Research and Otology (MEMRO 2009) Puria, S., Steele, C. ELSEVIER SCIENCE BV. 2010: 183–90

    Abstract

    The development of the unique capacity for high-frequency hearing in many mammals was due in part to changes in the middle ear, such as the evolution of three distinct middle-ear bones and distinct radial and circumferential collagen fiber layers in the eardrum. Ossicular moment(s) of inertia (MOI) and principal rotational axes, as well as eardrum surface areas, were calculated from micro-CT-based 3-D reconstructions of human, cat, chinchilla, and guinea pig temporal bones. For guinea pig and chinchilla, the fused malleus-incus complex rotates about an anterior-posterior axis, due to the relatively lightweight ossicles and bilateral symmetry of the eardrum. For human and cat, however, the MOI calculated for the unfused malleus are 5-6 times smaller for rotations about an inferior-superior axis than for rotations about the other two orthogonal axes. It is argued that these preferred motions, along with the presence of a mobile malleus-incus joint and asymmetric eardrum, enable efficient high-frequency sound transmission in spite of the relatively large ossicular masses of these species. This work argues that the upper-frequency hearing limit of a given mammalian species can in part be understood in terms of morphological co-adaptations of the eardrum and ossicular chain.

    View details for DOI 10.1016/j.heares.2009.10.013

    View details for Web of Science ID 000278583700023

    View details for PubMedID 19878714

  • GARDNER LINDZEY 27 NOVEMBER 1920 . 4 FEBRUARY 2008 PROCEEDINGS OF THE AMERICAN PHILOSOPHICAL SOCIETY Aronson, E., Luce, R. D., Steele, C., Suppes, P. 2010; 154 (1): 103-107
  • Ambient Belonging: How Stereotypical Cues Impact Gender Participation in Computer Science JOURNAL OF PERSONALITY AND SOCIAL PSYCHOLOGY Cheryan, S., Plaut, V. C., Davies, P. G., Steele, C. M. 2009; 97 (6): 1045-1060

    Abstract

    People can make decisions to join a group based solely on exposure to that group's physical environment. Four studies demonstrate that the gender difference in interest in computer science is influenced by exposure to environments associated with computer scientists. In Study 1, simply changing the objects in a computer science classroom from those considered stereotypical of computer science (e.g., Star Trek poster, video games) to objects not considered stereotypical of computer science (e.g., nature poster, phone books) was sufficient to boost female undergraduates' interest in computer science to the level of their male peers. Further investigation revealed that the stereotypical broadcast a masculine stereotype that discouraged women's sense of ambient belonging and subsequent interest in the environment (Studies 2, 3, and 4) but had no similar effect on men (Studies 3, 4). This masculine stereotype prevented women's interest from developing even in environments entirely populated by other women (Study 2). Objects can thus come to broadcast stereotypes of a group, which in turn can deter people who do not identify with these stereotypes from joining that group.

    View details for DOI 10.1037/a0016239

    View details for Web of Science ID 000272496400008

    View details for PubMedID 19968418

  • Stereotype threat and inflexible perseverance in problem solving JOURNAL OF EXPERIMENTAL SOCIAL PSYCHOLOGY Carr, P. B., Steele, C. M. 2009; 45 (4): 853-859
  • Isokinetic Resistance Training Increases Tibial Bending Stiffness in Young Women CALCIFIED TISSUE INTERNATIONAL Miller, L. E., Nickols-Richardson, S. M., Wootten, D. F., Ramp, W. K., Steele, C. R., Cotton, J. R., Carneal, J. P., Herbert, W. G. 2009; 84 (6): 446-452

    Abstract

    Bone mineral content (BMC) and bone mineral density (BMD) are common but imperfect surrogate measures of bone strength. The mechanical response tissue analyzer is a device that measures long bone bending stiffness (EI), which strongly predicts bone breaking strength. We hypothesized that isokinetic resistance training of the knee flexor and extensor muscles would increase tibial EI, BMC, and BMD in young women. Fifty-two women, aged 18-26 years, performed concentric (CON, n = 30) or eccentric (ECC, n = 22) isokinetic resistance training with the nondominant leg three times per week for 20 weeks. Before and after the training period, subjects were tested for CON and ECC peak torque of the knee flexor and extensor muscles with isokinetic dynamometry, tibial BMC and BMD using dual-energy X-ray absorptiometry, and tibial EI using mechanical response tissue analysis. Both training groups increased CON (15-21%) and ECC (17-31%) peak torque vs. the untrained leg. Tibial EI increased in the entire cohort (26%) and in each training group (CON 34%, ECC 16%) vs. the untrained tibia. Tibial BMC and BMD increased in the trained and untrained tibiae, with no significant differences between limbs. No differential tibial EI or bone mineral outcomes were observed between the CON and ECC training groups. In summary, CON and ECC isokinetic resistance training increased tibial EI, but not BMC or BMD, in young women.

    View details for DOI 10.1007/s00223-009-9247-5

    View details for Web of Science ID 000266478800004

    View details for PubMedID 19407920

  • A COCHLEAR MODEL USING THE TIME-AVERAGED LAGRANGIAN AND THE PUSH-PULL MECHANISM IN THE ORGAN OF CORTI JOURNAL OF MECHANICS OF MATERIALS AND STRUCTURES Yoon, Y., Puria, S., Steele, C. R. 2009; 4 (5): 977-986
  • A MULTISCALE MODEL OF THE ORGAN OF CORTI JOURNAL OF MECHANICS OF MATERIALS AND STRUCTURES Steele, C. R., de Monvel, J. B., Puria, S. 2009; 4 (4): 755-778
  • HOOK REGION REPRESENTED IN A COCHLEAR MODEL 10th International Workshop on the Mechanics of Hearing Steele, C. R., Kim, N., Puria, S. WORLD SCIENTIFIC PUBL CO PTE LTD. 2009: 323–329
  • COCHLEAR MODELING USING "TIME-AVERAGED LAGRANGIAN" METHOD: COMPARISON WITH V-BM, P-ST, AND Z(C) MEASUREMENTS 10th International Workshop on the Mechanics of Hearing Yoon, Y., Kim, N., Puria, S., Steele, C. R. WORLD SCIENTIFIC PUBL CO PTE LTD. 2009: 330–336
  • A nation challenged: The impact of foreign threat on America's tolerance for diversity JOURNAL OF PERSONALITY AND SOCIAL PSYCHOLOGY Davies, P. G., Steele, C. M., Markus, H. R. 2008; 95 (2): 308-318

    Abstract

    Three experiments investigated how perceived foreign threats to the United States can influence Americans' endorsement of assimilation and multiculturalism as models for foreign and domestic intergroup relations. The initial study, conducted during the 6-month anniversary of the September 11, 2001, terrorist attacks (9/11), discovered that a diverse group of Americans preferred assimilation as a foreign policy and multiculturalism as a domestic policy. After reading that foreigners were supporting the dominant global status of the United States, however, Americans in Experiment 2 no longer expressed this preference for assimilation as a model for foreign intergroup relations. Experiment 3 discovered that Americans primed with 9/11 (i.e., a foreign threat) revealed higher levels of national identity than did those primed with the Columbine massacre (i.e., a domestic threat); moreover, level of national identity predicted support for multiculturalism as a domestic policy and assimilation as a foreign policy.

    View details for DOI 10.1037/0022-3514.95.2.308

    View details for Web of Science ID 000257845500005

    View details for PubMedID 18665704

  • Finite element modeling of acousto-mechanical coupling in the cat middle ear JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Tuck-Lee, J. P., Pinsky, P. M., Steele, C. R., Puria, S. 2008; 124 (1): 348-362

    Abstract

    The function of the middle ear is to transfer acoustic energy from the ear canal to the cochlea. An essential component of this system is the tympanic membrane. In this paper, a new finite element model of the middle ear of the domestic cat is presented, generated in part from cadaver anatomy via microcomputed tomographic imaging. This model includes a layered composite model of the eardrum, fully coupled with the acoustics in the ear canal and middle-ear cavities. Obtaining the frequency response from 100 Hz to 20 kHz is a computationally challenging task, which has been accomplished by using a new adaptive implementation of the reduced-order matrix Padé-via-Lanczos algorithm. The results are compared to established physiological data. The fully coupled model is applied to study the role of the collagen fiber sublayers of the eardrum and to investigate the relationship between the structure of the middle-ear cavities and its function. Three applications of this model are presented, demonstrating the shift in the middle-ear resonance due to the presence of the septum that divides the middle-ear cavity space, the significance of the radial fiber layer on high frequency transmission, and the importance of the transverse shear modulus in the eardrum microstructure.

    View details for DOI 10.1121/1.2912438

    View details for Web of Science ID 000257768000034

    View details for PubMedID 18646982

    View details for PubMedCentralID PMC2677330

  • Social identity contingencies: How diversity cues signal threat or safety for African Americans in mainstream institutions 5th Biennial Convention of the Society-for-the-Psychological-Study-of-Social-Issues Purdie-Vaughns, V., Steele, C. A., Davies, P. G., Ditlmann, R., Crosby, J. R. AMER PSYCHOLOGICAL ASSOC. 2008: 615–30

    Abstract

    This research demonstrates that people at risk of devaluation based on group membership are attuned to cues that signal social identity contingencies--judgments, stereotypes, opportunities, restrictions, and treatments that are tied to one's social identity in a given setting. In 3 experiments, African American professionals were attuned to minority representation and diversity philosophy cues when they were presented as a part of workplace settings. Low minority representation cues coupled with colorblindness (as opposed to valuing diversity) led African American professionals to perceive threatening identity contingencies and to distrust the setting (Experiment 1). The authors then verified that the mechanism mediating the effect of setting cues on trust was identity contingent evaluations (Experiments 2 & 3). The power of social identity contingencies as they relate to underrepresented groups in mainstream institutions is discussed.

    View details for DOI 10.1037/0022-3514.94.4.615

    View details for Web of Science ID 000254363300005

    View details for PubMedID 18361675

  • The space between us: Stereotype threat and distance in interracial contexts JOURNAL OF PERSONALITY AND SOCIAL PSYCHOLOGY Goff, P. A., Steele, C. M., Davies, P. G. 2008; 94 (1): 91-107

    Abstract

    Four studies investigate the role that stereotype threat plays in producing racial distancing behavior in an anticipated conversation paradigm. It was hypothesized that the threat of appearing racist may have the ironic effect of causing Whites to distance themselves from Black conversation partners. In Study 1, participants distanced themselves more from Black partners under conditions of threat, and this distance correlated with the activation of a "White racist" stereotype. In Study 2, it was demonstrated that Whites' interracial distancing behavior was not predicted by explicit or implicit prejudice. Study 3 provides evidence that conceiving of interracial interactions as opportunities to learn may attenuate the negative consequences of threat for Whites. Study 4 found that Whites have conscious access to their experience of stereotype threat and that this awareness may mediate the relationship between threat and distance. These results are discussed within a broader discourse of racial distancing and the possibility that certain identity threats may be as important as prejudice in determining the outcomes of interracial interactions.

    View details for DOI 10.1037/0022-3514.94.1.91

    View details for Web of Science ID 000251826500007

    View details for PubMedID 18179320

  • Cochlear anatomy using micro computed tomography (mu CT) imaging Conference on Photonic Therapeutics and Diagnostics IV Kim, N., Yoon, Y., Steele, C., Puria, S. SPIE-INT SOC OPTICAL ENGINEERING. 2008

    View details for DOI 10.1117/12.774349

    View details for Web of Science ID 000255314100031

  • The ethics of characterizing difference: guiding principles on using racial categories in human genetics GENOME BIOLOGY Lee, S. S., Mountain, J., Koenig, B., Altman, R., Brown, M., Camarillo, A., Cavalli-Sforza, L., Cho, M., Eberhardt, J., Feldman, M., Ford, R., Greely, H., King, R., Markus, H., Satz, D., Snipp, M., Steele, C., Underhill, P. 2008; 9 (7)

    Abstract

    We are a multidisciplinary group of Stanford faculty who propose ten principles to guide the use of racial and ethnic categories when characterizing group differences in research into human genetic variation.

    View details for DOI 10.1186/gb-2008-9-7-404

    View details for Web of Science ID 000258773600005

    View details for PubMedID 18638359

    View details for PubMedCentralID PMC2530857

  • Isokinetic training increases ulnar bending stiffness and bone mineral in young women BONE Miller, L. E., Wootten, D. F., Nickols-Richardson, S. M., Ramp, W. K., Steele, C. R., Cotton, J. R., Carneal, J. P., Herbert, W. G. 2007; 41 (4): 685-689

    Abstract

    Numerous studies have investigated the effects of physical activity on bone health; however, little is known about the effects of isokinetic strength training on bone. While bone mineral density (BMD) is widely used to assess bone health and fracture risk, there are several limitations of this measure that warrant new technology development to measure bone strength. The mechanical response tissue analyzer (MRTA) assesses bone strength by measuring maximal bending stiffness (EI). We hypothesized that isokinetic strength training of the elbow flexors and extensors would increase ulnar EI, BMD, and bone mineral content (BMC) in young women. Fifty-four women trained the nondominant arm 3 times per week for 20 weeks; 32 trained concentrically (CON) and 22 trained eccentrically (ECC). Subjects were assessed for the following variables pre- and post-training: CON and ECC peak torque of the elbow flexors and extensors with isokinetic dynamometry, ulnar mineral content and density using dual-energy X-ray absorptiometry, and ulnar EI using MRTA. Isokinetic training increased CON (17%) and ECC (17%) peak torque, even when controlling for changes in the untrained arm. Eccentric training increased CON and ECC peak torque while CON training improved CON peak torque only. Isokinetic training increased ulnar EI 28%, which was statistically greater than the untrained arm. Ulnar EI increased 25% with CON training and 32% with ECC training. Both training modes resulted in greater EI gains compared to the untrained limb. Isokinetic training increased ulnar BMC (2.7%) and BMD (2.3%), even when controlling for untrained ulna changes. Both training modalities resulted in BMC and BMD increases; however, only CON training yielded gains when controlling for changes in the untrained limb. In conclusion, isokinetic strength training increases ulnar EI, BMC, and BMD in young women; no statistical differences were noted between CON and ECC training modes.

    View details for DOI 10.1016/j.bone.2007.07.004

    View details for Web of Science ID 000249800800024

    View details for PubMedID 17693150

  • Calculation of inertial properties of the malleus-incus complex from micro-CT imaging 9th Pan American Congress of Applied Mechanics (PACAM 9) Sim, J. H., Puria, S., Steele, C. R. MATHEMATICAL SCIENCE PUBL. 2007: 1515–24
  • Frequency and spatial response of basilar membrane vibration in a three-dimensional gerbil cochlear model 9th Pan American Congress of Applied Mechanics (PACAM 9) Yoon, Y., Puria, S., Steele, C. R. MATHEMATICAL SCIENCE PUBL. 2007: 1449–58
  • Signaling threat: How situational cues affect women in math, science, and engineering settings PSYCHOLOGICAL SCIENCE Murphy, M. C., Steele, C. M., Gross, J. J. 2007; 18 (10): 879-885

    Abstract

    This study examined the cues hypothesis, which holds that situational cues, such as a setting's features and organization, can make potential targets vulnerable to social identity threat. Objective and subjective measures of identity threat were collected from male and female math, science, and engineering (MSE) majors who watched an MSE conference video depicting either an unbalanced ratio of men to women or a balanced ratio. Women who viewed the unbalanced video exhibited more cognitive and physiological vigilance, and reported a lower sense of belonging and less desire to participate in the conference, than did women who viewed the gender-balanced video. Men were unaffected by this situational cue. The implications for understanding vulnerability to social identity threat, particularly among women in MSE settings, are discussed.

    View details for Web of Science ID 000249827200007

    View details for PubMedID 17894605

  • Intracochlear pressure and derived quantities from a three-dimensional model JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Yoon, Y., Puria, S., Steele, C. R. 2007; 122 (2): 952-966

    Abstract

    Intracochlear pressure is calculated from a physiologically based, three-dimensional gerbil cochlea model. Olson [J. Acoust. Soc. Am. 103, 3445-3463 (1998); 110, 349-367 (2001)] measured gerbil intracochlear pressure and provided approximations for the following derived quantities: (1) basilar membrane velocity, (2) pressure across the organ of Corti, and (3) partition impedance. The objective of this work is to compare the calculations and measurements for the pressure at points and the derived quantities. The model includes the three-dimensional viscous fluid and the pectinate zone of the elastic orthotropic basilar membrane with dimensional and material property variation along its length. The arrangement of outer hair cell forces within the organ of Corti cytoarchitecture is incorporated by adding the feed-forward approximation to the passive model as done previously. The intracochlear pressure consists of both the compressive fast wave and the slow traveling wave. A Wentzel-Kramers-Brillowin asymptotic and numerical method combined with Fourier series expansions is used to provide an efficient procedure that requires about 1 s to compute the response for a given frequency. Results show reasonably good agreement for the direct pressure and the derived quantities. This confirms the importance of the three-dimensional motion of the fluid for an accurate cochlear model.

    View details for DOI 10.1121/1.2747162

    View details for Web of Science ID 000248644100025

    View details for PubMedID 17672644

  • Situational disengagement and persistence in the face of adversity JOURNAL OF EXPERIMENTAL SOCIAL PSYCHOLOGY Nussbaum, A. D., Steele, C. M. 2007; 43 (1): 127-134
  • Basilar Membrane Velocity and Organ of Corti Impedance from the Physiologically-Based Three-Dimensional Cochlear Model World Congress on Medical Physics and Biomedical Engineering Yoon, Y. J., Puria, S., Steele, C. R. SPRINGER-VERLAG BERLIN. 2007: 46–49
  • MIDDLE EAR MORPHOMETRY FROM CADAVERIC TEMPORAL BONE MICRO-CT IMAGING 4th International Symposium on Middle Ear Mechanics in Research and Otology Puria, S., Sim, J. H., Shin, M., Tuck-Lee, J., Steele, C. R. WORLD SCIENTIFIC PUBL CO PTE LTD. 2007: 259–268
  • The discordant eardrum PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Fay, J. P., Puria, S., Steele, C. R. 2006; 103 (52): 19743-19748

    Abstract

    At frequencies above 3 kHz, the tympanic membrane vibrates chaotically. By having many resonances, the eardrum can transmit the broadest possible bandwidth of sound with optimal sensitivity. In essence, the eardrum works best through discord. The eardrum's success as an instrument of hearing can be directly explained through a combination of its shape, angular placement, and composition. The eardrum has a conical asymmetrical shape, lies at a steep angle with respect to the ear canal, and has organized radial and circumferential collagen fiber layers that provide the scaffolding. Understanding the role of each feature in hearing transduction will help direct future surgical reconstructions, lead to improved microphone and loudspeaker designs, and provide a basis for understanding the different tympanic membrane structures across species. To analyze the significance of each anatomical feature, a computer simulation of the ear canal, eardrum, and ossicles was developed. It is shown that a cone-shaped eardrum can transfer more force to the ossicles than a flat eardrum, especially at high frequencies. The tilted eardrum within the ear canal allows it to have a larger area for the same canal size, which increases sound transmission to the cochlea. The asymmetric eardrum with collagen fibers achieves optimal transmission at high frequencies by creating a multitude of deliberately mistuned resonances. The resonances are summed at the malleus attachment to produce a smooth transfer of pressure across all frequencies. In each case, the peculiar properties of the eardrum are directly responsible for the optimal sensitivity of this discordant drum.

    View details for DOI 10.1073/pnas.0603898104

    View details for Web of Science ID 000243285500026

    View details for PubMedID 17170142

    View details for PubMedCentralID PMC1702319

  • The detrimental effects of a suggestion of sexism in an instruction situation JOURNAL OF EXPERIMENTAL SOCIAL PSYCHOLOGY Adams, G., Garcia, D. M., Purdle-Vaughns, V., Steele, C. M. 2006; 42 (5): 602-615
  • An anisotropic-viscoplastic model of plant cell morphogenesis by tip growth INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY Dumais, J., Shaw, S. L., Steele, C. R., Long, S. R., Ray, P. M. 2006; 50 (2-3): 209-222

    Abstract

    Plant cell morphogenesis depends critically on two processes: the deposition of new wall material at the cell surface and the mechanical deformation of this material by the stresses resulting from the cell's turgor pressure. We developed a model of plant cell morphogenesis that is a first attempt at integrating these two processes. The model is based on the theories of thin shells and anisotropic viscoplasticity. It includes three sets of equations that give the connection between wall stresses, wall strains and cell geometry. We present an algorithm to solve these equations numerically. Application of this simulation approach to the morphogenesis of tip-growing cells illustrates how the viscoplastic properties of the cell wall affect the shape of the cell at steady state. The same simulation approach was also used to reproduce morphogenetic transients such as the initiation of tip growth and other non-steady changes in cell shape. Finally, we show that the mechanical anisotropy built into the model is required to account for observed patterns of wall expansion in plant cells.

    View details for DOI 10.1387/ijdb.052066jd

    View details for Web of Science ID 000236977200014

    View details for PubMedID 16479489

  • Developing a physical model of the human cochlea using microfabrication methods AUDIOLOGY AND NEURO-OTOLOGY Wittbrodt, M. J., Steele, C. R., Puria, S. 2006; 11 (2): 104-112

    Abstract

    Advances in micro-machining technology have provided the opportunity to explore possibilities of creating life-sized physical models of the cochlea. The physical model of the cochlea consists of two fluid-filled channels separated by an elastic partition. The partition is micro-machined from silicon and uses a 36-mm linearly tapered polyimide plate with a width of 100 microm at the basal end and 500 microm at the apex to represent the basilar membrane. Thicknesses from 1 to 5 microm have been fabricated. Discrete aluminum fibers (1.5 microm in width) are machined to create direction-dependent properties. A 0.5 x 0.5 mm opening represents the helicotrema. The fluid channels are machined from plexiglas using conventional machining methods. A magnet-coil system excites the fluid channel. Measurements on a model with thickness 4.75 microm show a velocity gain of 4 and phase of 3.5 pi radians at a location 23 mm from the base. Mathematical modeling using a 3-D formulation confirm the general characteristics of the measured response.

    View details for DOI 10.1159/000090683

    View details for Web of Science ID 000235031800006

    View details for PubMedID 16439833

  • Multi-scale model of the organ of Corti: IHC tip link tension 9th International Symposium on Auditory Mechanisms Steele, C. R., Puria, S. WORLD SCIENTIFIC PUBL CO PTE LTD. 2006: 425–432
  • Developing a life-sized physical model of the human cochlea 9th International Symposium on Auditory Mechanisms Wittbrodt, M. J., Steele, C. R., Puria, S. WORLD SCIENTIFIC PUBL CO PTE LTD. 2006: 512–513
  • Intracochlear pressure and organ of corti impedance from a linear active three-dimensional model ORL-JOURNAL FOR OTO-RHINO-LARYNGOLOGY AND ITS RELATED SPECIALTIES Yoon, Y., Puria, S., Steele, C. R. 2006; 68 (6): 365-372

    Abstract

    Intracochlear pressure and basilar membrane (BM) velocity are calculated from a physiologically based chinchilla cochlea model . The model includes three-dimensional viscous fluid and the pectinate zone of the elastic BM with dimensional and material property variation along its length. The passive response shows excellent agreement with measurement at high sound pressure levels. The active process is represented by adding the motility of the outer hair cells (OHCs) to the passive model with the feed-forward approximation of the organ of Corti (OC), as was done previously. The current model explains recent observations including: (1) agreement with characteristic frequency (CF)-to-place map, (2) CF shift in the active model, (3) BM displacement gain from OHC motility, (4) lower intracochlear pressure gain than BM displacement gain, and (5) OC impedance (Z(OC)).

    View details for DOI 10.1159/000095279

    View details for Web of Science ID 000241664500012

    View details for PubMedID 17065831

  • Force on inner hair cell cilia 8th Pan American Congress of Applied Mechanics (PACAM 8) Steele, C. R., Puria, S. PERGAMON-ELSEVIER SCIENCE LTD. 2005: 5887–5904
  • Three approaches for estimating the elastic modulus of the tympanic membrane JOURNAL OF BIOMECHANICS Fay, J., Puria, S., Decraemer, W. F., Steele, C. 2005; 38 (9): 1807-1815

    Abstract

    The function of the middle ear is to resolve the acoustic impedance mismatch between the air in the ear canal and the fluid of the inner ear. Without this impedance matching, very little acoustic energy would be absorbed into the cochlea. The first step in this process is the tympanic membrane (TM) converting sound in the ear canal into vibrations of the middle ear bones. Understanding how the TM manages its task so successfully over such a broad frequency range should lead to more satisfactory and less variable TM repairs (myringoplasty). In addition, understanding the mechanics of the TM is necessary to improve the coupling between ossicular prostheses and the TM. Mathematical models have played a central role in helping the research community understand the mechanics of the eardrum. However, all models require parameters as inputs. Unfortunately, most of the parameters needed for modeling the TM are not well known. In this work, several approaches for inferring the material properties of the TM are explored. First, constitutive modeling is used to estimate an elastic modulus based on the elastic modulus of collagen and experimentally observed fiber densities. Second, experimental tension and bending test results from the literature are re-interpreted using composite laminate theory. Lastly, dynamic measurements of the cat TM are used in conjunction with a composite shell model to bound the material parameters. Values from the literature, both measurement and modeling efforts, and from the present analysis are brought together to form a coherent picture of the TM's material properties. In the human, the data bound the elastic modulus between 0.1 and 0.3 GPa. In the cat, the data suggest a range of 0.1-0.4 GPa. These values are significantly higher than previous estimates.

    View details for DOI 10.1016/j.jbiomech.2004.08.022

    View details for Web of Science ID 000231253500007

    View details for PubMedID 16023467

  • Ulnar and tibial bending stiffness as an index of bone strength in synchronized swimmers and gymnasts EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY Liang, M. T., Arnaud, S. B., Steele, C. R., Hatch, P., Moreno, A. 2005; 94 (4): 400-407

    Abstract

    The purpose of this study is to compare a mechanical property of bone in world-class female athletes with different loading histories. Bone bending stiffness or EI (E is the modulus of elasticity and I, the moment of inertia) was measured noninvasively with the mechanical response tissue analyzer, that analyzes the response of bone to a vibratory stimulus. We evaluated the ulna, ulnar width, wrist density and tibia in 13 synchronized swimmers (SYN), eight gymnasts (GYM) and 16 untrained women (UNT) of similar age. Muscle strength in the flexors and extensors at elbows and knees was measured in the athletes. SYN were taller than GYM or UNT (168 +/- 0.7 vs. 152 +/- 1.1 or 157 +/- 1.2 cm, P < 0.01). Ulnar EI, Nm(2), was similar in SYN and GYM (41 +/- 5.4 vs. 42 +/- 4.2, NS) and 50% higher than in UNT (27 +/- 2.1, P < 0.05). Ulnar EI, Nm(2) was related to ulnar width (r = 0.497, P < 0.002, n = 37) but not to wrist density. Tibial EI, Nm(2), in SYN and GYM (270 +/- 42 vs. 285 +/- 49, NS) was similar and more than twice as high as in UNT (119 +/- 6; p < 0.05). Knee flexor strength measured at 60 degrees s(-1) and elbow extensor strength at 200 degrees s(-1) correlated with tibial EI (r = 0.44 and 0.41, P < 0.05). In spite of different loading histories, the tibiae and ulnas of world-class athletes showed similar high values for bending stiffness that exceeded values in untrained women. EI in the ulna could be related to bone width and in the tibia, to muscle strength.

    View details for DOI 10.1007/s00421-005-1351-2

    View details for Web of Science ID 000230071900007

    View details for PubMedID 15864633

  • Influence of increased mechanical loading by hypergravity on the microtubule cytoskeleton and prostaglandin E-2 release in primary osteoblasts AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY Searby, N. D., Steele, C. R., Globus, R. K. 2005; 289 (1): C148-C158

    Abstract

    Cells respond to a wide range of mechanical stimuli such as fluid shear and strain, although the contribution of gravity to cell structure and function is not understood. We hypothesized that bone-forming osteoblasts are sensitive to increased mechanical loading by hypergravity. A centrifuge suitable for cell culture was developed and validated, and then primary cultures of fetal rat calvarial osteoblasts at various stages of differentiation were mechanically loaded using hypergravity. We measured microtubule network morphology as well as release of the paracrine factor prostaglandin E2 (PGE2). In immature osteoblasts, a stimulus of 10x gravity (10 g) for 3 h increased PGE2 2.5-fold and decreased microtubule network height 1.12-fold without affecting cell viability. Hypergravity (3 h) caused dose-dependent (5-50 g) increases in PGE2 (5.3-fold at 50 g) and decreases (1.26-fold at 50 g) in microtubule network height. PGE2 release depended on duration but not orientation of the hypergravity load. As osteoblasts differentiated, sensitivity to hypergravity declined. We conclude that primary osteoblasts demonstrate dose- and duration-dependent sensitivity to gravitational loading, which appears to be blunted in mature osteoblasts.

    View details for DOI 10.1152/ajpcell.00524.2003

    View details for Web of Science ID 000229794100018

    View details for PubMedID 15728710

  • Clearing the air: Identity safety moderates the effects of stereotype threat on women's leadership aspirations JOURNAL OF PERSONALITY AND SOCIAL PSYCHOLOGY Davies, P. G., Spencer, S. J., Steele, C. M. 2005; 88 (2): 276-287

    Abstract

    Exposing participants to gender-stereotypic TV commercials designed to elicit the female stereotype, the present research explored whether vulnerability to stereotype threat could persuade women to avoid leadership roles in favor of nonthreatening subordinate roles. Study 1 confirmed that exposure to the stereotypic commercials undermined women's aspirations on a subsequent leadership task. Study 2 established that varying the identity safety of the leadership task moderated whether activation of the female stereotype mediated the effect of the commercials on women's aspirations. Creating an identity-safe environment eliminated vulnerability to stereotype threat despite exposure to threatening situational cues that primed stigmatized social identities and their corresponding stereotypes.

    View details for DOI 10.1037/0022-3514.88.2.276

    View details for Web of Science ID 000226585400004

    View details for PubMedID 15841859

  • Introduction to the Lewin Award address by Sam Gaertner and Jack Dovidio JOURNAL OF SOCIAL ISSUES Steele, C. M. 2005; 61 (3): 611-614
  • Not just a test NATION Steele, C. M. 2004; 278 (17): 38-41
  • Identity bifurcation in response to stereotype threat: Women and mathematics JOURNAL OF EXPERIMENTAL SOCIAL PSYCHOLOGY Pronin, E., Steele, C. M., Ross, L. 2004; 40 (2): 152-168
  • Three-dimensional measurements and analysis of the isolated malleus-incus complex 3rd Symposium on Middle Ear Mechanics in Research and Otology Sim, J. H., Puria, S., Steele, C. R. WORLD SCIENTIFIC PUBL CO PTE LTD. 2004: 61–67
  • Stereotype threat does not live by Steele and Aronson (1995) alone AMERICAN PSYCHOLOGIST Steele, C. M., Aronson, J. A. 2004; 59 (1): 47-48

    View details for DOI 10.1037/0003-066X.59.1.47

    View details for Web of Science ID 000188285300009

    View details for PubMedID 14736323

  • Response suppression and transient behavior in a nonlinear active cochlear model with feed-forward 7th Pan American Congress of Applied Mechanics (PACAM 7) Lim, K. M., Steele, C. R. PERGAMON-ELSEVIER SCIENCE LTD. 2003: 5097–5107
  • Through the back door to theory PSYCHOLOGICAL INQUIRY Steele, C. M. 2003; 14 (3-4): 314-317
  • Analysis of forces on inner hair cell cilia Conference on Biophysics of the Cochlea - Molecules to Models Steele, C. R., Puria, S. WORLD SCIENTIFIC PUBL CO PTE LTD. 2003: 359–367
  • Stereotype threat and employment testing: A commentary HUMAN PERFORMANCE Steele, C. M., Davies, P. G. 2003; 16 (3): 311-326
  • An edge dislocation interacting with a slightly wavy interface INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE Xiao, Z. M., Chen, B. J., Steele, C. R. 2002; 40 (19): 2137-2161
  • A three-dimensional nonlinear active cochlear model analyzed by the WKB-numeric method HEARING RESEARCH Lim, K. M., Steele, C. R. 2002; 170 (1-2): 190-205

    Abstract

    A physiologically based nonlinear active cochlear model is presented. The model includes the three-dimensional viscous fluid effects, an orthotropic cochlear partition with dimensional and material property variation along its length, and a nonlinear active feed-forward mechanism of the organ of Corti. A hybrid asymptotic and numerical method combined with Fourier series expansions is used to provide a fast and efficient iterative procedure for modeling and simulation of the nonlinear responses in the active cochlea. The simulation results for the chinchilla cochlea compare very well with experimental measurements, capturing several nonlinear features observed in basilar membrane responses. These include compression of response with stimulus level, two-tone suppressions, and generation of harmonic distortion and distortion products.

    View details for Web of Science ID 000177804600018

    View details for PubMedID 12208552

  • Contending with group image: The psychology of stereotype and social identity threat ADVANCES IN EXPERIMENTAL SOCIAL PSYCHOLOGY, VOL 34 Steele, C. M., Spencer, S. J., Aronson, J. 2002; 34: 379-440
  • Effects of chair restraint on the strength of the tibia in rhesus monkeys JOURNAL OF MEDICAL PRIMATOLOGY Hutchinson, T. M., Bakulin, A. V., Rakhmanov, A. S., MARTIN, R. B., Steele, C. R., Arnaud, S. B. 2001; 30 (6): 313-321

    Abstract

    To determine the effects of the relative inactivity and unloading on the strength of the tibias of monkeys, Macaca mulatta, we used a non-invasive test to measure bending stiffness, or EI (Nm2), a mechanical property. The technique was validated by comparisons of in vivo measurements with standard measures of EI in the same bones post-mortem (r2 = 0.95, P < 0.0001). Inter-test precision was 4.28+/-1.4%. Normative data in 24 monkeys, 3.0+/-0.7 years and 3.6+/-0.6 kg, revealed EI to be 16% higher in the right than left tibia (4.4+/-1.6 vs. 3.7+/-1.6 Nm2, P < 0.05). Five monkeys, restrained in chairs for 14 days, showed decreases in EI. There were no changes in EI in two chaired monkeys that lost weight during a 2-week space flight. The factors that account for both the decreases in bone mechanical properties after chair restraint at 1 g and lack of change after microgravity remain to be identified. Metabolic factors associated with body weight changes are suggested by our results.

    View details for Web of Science ID 000174105300005

    View details for PubMedID 11990531

  • African Americans and high blood pressure: The role of stereotype threat PSYCHOLOGICAL SCIENCE Blascovich, J., Spencer, S. J., Quinn, D., Steele, C. 2001; 12 (3): 225-229

    Abstract

    We examined the effect of stereotype threat on blood pressure reactivity. Compared with European Americans, and African Americans under little or no stereotype threat, African Americans under stereotype threat exhibited larger increases in mean arterial blood pressure during an academic test, and performed more poorly on difficult test items. We discuss the significance of these findings for understanding the incidence of hypertension among African Americans.

    View details for Web of Science ID 000169288000007

    View details for PubMedID 11437305

  • Bending and symmetric pinching of pressurized tubes INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES Fay, J. P., Steele, C. R. 2000; 37 (46-47): 6917-6931
  • Colorblindness as a barrier to inclusion: Assimilation and nonimmigrant minorities DAEDALUS Markus, H. R., Steele, C. M., Steele, D. M. 2000; 129 (4): 233-259
  • Do messages about health risks threaten the self? Increasing the acceptance of threatening health messages via self-affirmation PERSONALITY AND SOCIAL PSYCHOLOGY BULLETIN Sherman, D. A., Nelson, L. D., Steele, C. M. 2000; 26 (9): 1046-1058
  • Efficacy of monitoring long-bone fracture healing by measurement of either bone stiffness or resonant frequency: Numerical simulation JOURNAL OF ORTHOPAEDIC RESEARCH Roberts, S. G., Steele, C. R. 2000; 18 (5): 691-697

    Abstract

    Development of noninvasive mechanical tests to monitor fracture healing has been hindered because relationships between bone geometry, measurement conditions, and fracture callus strength are not well understood. Beam theory was used to analyze the effects of fracture length, fracture location, end conditions, and fracture callus stiffness on mechanical properties (resonant frequency, bending stiffness, and torsional stiffness) of healing bone. Actual bone mineral geometry from a human tibia, quantified every 1 mm, was used in the beam analysis. Geometry of the fracture callus segment was uniformly scaled from the values for intact bone. Experimental tests on multisegmented machined rods were used to verify analytical methods. Mechanical properties of the healing bone initially increased very rapidly to 30-70% of the stiffness of intact bone, depending on the configuration. The increases then tapered off dramatically. Lateral bending stiffness was sensitive to changes in callus properties for a larger portion of the healing process than was either torsional stiffness or resonant frequency. Because callus strength increases at half the rate of callus stiffness, measures of whole-bone mechanical properties can provide insight into changes in callus strength until a maximum of less than one-half the strength of intact bone is regained. The analytical method presented is proposed for clinical use to develop individualized models of bone, fracture, and fixation conditions to identify early stages of healing. Because increases in whole-bone mechanical properties are small in the later stages of fracture healing, however, such measures must be used prudently beyond the initial stages.

    View details for Web of Science ID 000165616800002

    View details for PubMedID 11117288

  • When beliefs yield to evidence: Reducing biased evaluation by affirming the self PERSONALITY AND SOCIAL PSYCHOLOGY BULLETIN Cohen, G. L., Aronson, J., Steele, C. M. 2000; 26 (9): 1151-1164
  • Shell stability related to pattern formation in plants JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME Steele, C. R. 2000; 67 (2): 237-247
  • New evidence for the role of mechanical forces in the shoot apical meristem JOURNAL OF PLANT GROWTH REGULATION Dumais, J., Steele, C. R. 2000; 19 (1): 7-18
  • Inflation of rolled tubes IUTAM-IASS Symposium on Deployable Structures, Theory and Applications Steele, C. R., Fay, J. P. SPRINGER. 2000: 393–403
  • Building a physical cochlear model on a silicon chip International Symposium on Recent Developments in Auditory Mechanics Lim, K. M., Fitzgerald, A. M., Steele, C. R., Puria, S. WORLD SCIENTIFIC PUBL CO PTE LTD. 2000: 223–229
  • The effect of eardrum inclination on ear canal acoustic impedance International Symposium on Recent Developments in Auditory Mechanics Fay, J. P., Puria, S., Steele, C. R. WORLD SCIENTIFIC PUBL CO PTE LTD. 2000: 3–9
  • Allport's legacy and the situational press of stereotypes JOURNAL OF SOCIAL ISSUES MARX, D. M., Brown, J. L., Steele, C. M. 1999; 55 (3): 491-502
  • The mentor's dilemma: Providing critical feedback across the racial divide PERSONALITY AND SOCIAL PSYCHOLOGY BULLETIN Cohen, G. L., Steele, C. M., Ross, L. D. 1999; 25 (10): 1302-1318
  • Toward three-dimensional analysis of cochlear structure ORL-JOURNAL FOR OTO-RHINO-LARYNGOLOGY AND ITS RELATED SPECIALTIES Steele, C. R. 1999; 61 (5): 238-251

    Abstract

    Recent results from a three-dimensional model of the cochlea are summarized. The features include physically realistic values of basilar membrane stiffness, mass, and fluid viscosity. The simple 'feed-forward' principle for the active process yields results in qualitative agreement with recent measurements in the cochlea. The limitation is a simplified representation of the organ of Corti, with two degrees of freedom representing the motion of the pectinate and arcuate zones of the basilar membrane. However, the inner sulcus fluid flow is included. The new feature presented in this paper is an approach to treat all the structural detail of the organ of Corti, with the sole input to the calculation in a form easily understood by anyone familiar with the cochlea. Specific results are shown for the Pakistani water buffalo, since a fairly complete anatomical description of this cochlea is available. The static stiffness from the calculation, based on only the anatomy and known values for the protein elastic moduli, are in remarkable agreement with recent measurements in the gerbil cochlea. Only preliminary results for the dynamic response with inviscid fluid are reported. Of interest, however, are the propagation modes related to significant fluid displacement and pressure in the different compartments of the organ of Corti.

    View details for Web of Science ID 000082989100002

    View details for PubMedID 10529645

  • Forces for rolling and asymmetric pinching of pressurized cylindrical tubes JOURNAL OF SPACECRAFT AND ROCKETS Fay, J. P., Steele, C. R. 1999; 36 (4): 531-537
  • Cochlear model with three-dimensional fluid, inner sulcus and feed-forward mechanism AUDIOLOGY AND NEURO-OTOLOGY Steele, C. R., Lim, K. M. 1999; 4 (3-4): 197-203

    Abstract

    A three-dimensional model of the guinea pig cochlea using the phase-integral method is presented. This model incorporates the viscous fluid effects in the cochlea, dimensional and material property variation along the cochlear duct and the active feed-forward mechanism of the outer hair cells. Two degrees of freedom of the basilar membrane are considered, which results in two traveling waves propagating along the duct for a given frequency. Basilar membrane response with the active feed-forward mechanism compares favorably with published experimental measurements.

    View details for Web of Science ID 000079661900013

    View details for PubMedID 10187930

  • 7R31. AMR Infobase of Journal Literature on CD-ROM, 1989-1997 (Reprinted from Appl Mech Rev, vol 51, July 1998) JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME Qatu, M. S., Steele, C. R. 1999; 121 (1): 115-115
  • When white men can't do math: Necessary and sufficient factors in stereotype threat JOURNAL OF EXPERIMENTAL SOCIAL PSYCHOLOGY Aronson, J., Lustina, M. J., Good, C., Keough, K., Steele, C. M. 1999; 35 (1): 29-46
  • Stereotype threat and women's math performance JOURNAL OF EXPERIMENTAL SOCIAL PSYCHOLOGY Spencer, S. J., Steele, C. M., Quinn, D. M. 1999; 35 (1): 4-28
  • Stereotyping and its threat are real AMERICAN PSYCHOLOGIST Steele, C. M. 1998; 53 (6): 680-681
  • Vibration of reflective beads placed on the basilar membrane HEARING RESEARCH Khanna, S. M., Ulfendahl, M., Steele, C. R. 1998; 116 (1-2): 71-85

    Abstract

    Most investigators place reflective beads on the basilar membrane to measure its vibration with optical methods. It is therefore important to find out if the beads faithfully follow the motion of the structures on which they are placed. Vibration of the beads on the basilar membrane and basilar membrane adjacent to the beads are measured in the third turn of the guinea pig cochlea in a temporal bone preparation. It is shown that the beads do not follow the motion of the organ. The mechanism by which this departure may occur is investigated by modeling the motion of the beads on the Claudius' cells.

    View details for Web of Science ID 000072171400008

    View details for PubMedID 9508030

  • A dynamic model of outer hair cell motility including intracellular and extracellular fluid viscosity JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Tolomeo, J. A., Steele, C. R. 1998; 103 (1): 524-534

    Abstract

    The deformation response of a guinea pig outer hair cell is modeled for mechanical and electrical stimulation up to 25 kHz. The analysis uses a Fourier series technique for a finite length cell surrounded internally and externally by a much larger continuum of viscous fluid. The analytical solution predicts that outer hair cell length changes occur due to applied mechanical or electrical stimulation without significant resonance, characteristic of a highly damped system. The deformation is found to have little attenuation up to a corner frequency of about 2 kHz for long cells and 10 kHz for short cells, in agreement with published experimental results. For electrical loading of 1 mV across the lateral cell wall, deformation for short cells is calculated to be greater than 1 nm for frequencies up to 20 kHz. These results support the proposition that in vivo the outer hair cell modifies the character of basilar membrane deformation on a cycle-by-cycle basis. An estimate of the capability of the cell to supply energy to the basilar membrane is given based on published values of outer hair cell material properties.

    View details for Web of Science ID 000071496900050

    View details for PubMedID 9440337

  • A threat in the air - How stereotypes shape intellectual identity and performance AMERICAN PSYCHOLOGIST Steele, C. M. 1997; 52 (6): 613-629

    Abstract

    A general theory of domain identification is used to describe achievement barriers still faced by women in advanced quantitative areas and by African Americans in school. The theory assumes that sustained school success requires identification with school and its subdomains; that societal pressures on these groups (e.g., economic disadvantage, gender roles) can frustrate this identification; and that in school domains where these groups are negatively stereotyped, those who have become domain identified face the further barrier of stereotype threat, the threat that others' judgments or their own actions will negatively stereotype them in the domain. Research shows that this threat dramatically depresses the standardized test performance of women and African Americans who are in the academic vanguard of their groups (offering a new interpretation of group differences in standardized test performance), that it causes disidentification with school, and that practices that reduce this threat can reduce these negative effects.

    View details for Web of Science ID A1997XA59600001

    View details for PubMedID 9174398

  • Fluid-structure interaction of the stereocilia bundle in relation to mechanotransduction JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA ZETES, D. E., Steele, C. R. 1997; 101 (6): 3593-3601

    Abstract

    Current hypotheses regarding mechanotransduction rely upon motion of the stereocilia relative to the apical surface of the hair cell. The viscosity of the surrounding endolymphatic fluid will, however, attenuate stereocilia motion at higher frequencies of excitation. To investigate stereocilia motion for physiologically reasonable deflections and frequencies of excitation, the fluid-structure interaction of the stereocilia bundle is considered analytically. Solutions in the frequency domain are determined for stereocilia bundle dimensions at several locations along the cochlear duct of the chinchilla. Results indicate that motion of the stereocilia is analogous to that of a low-pass filter. Comparison of these solutions with Greenwood's frequency-place map demonstrates that motion of the stereocilia bundle exists without substantial attenuation at least up to frequencies appropriate for the location of the corresponding hair cell along the cochlear duct. The variation in stereocilia morphology within the mammalian cochlea thus appears to provide a collection of low-pass mechanoreceptors, arranged in order of increasing corner frequency across the auditory spectrum.

    View details for Web of Science ID A1997XE28800040

    View details for PubMedID 9193047

  • Kinematic analysis of shear displacement as a means for operating mechanotransduction channels in the contact region between adjacent stereocilia of mammalian cochlear hair cells PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES Furness, D. N., ZETES, D. E., Hackney, C. M., Steele, C. R. 1997; 264 (1378): 45-51

    Abstract

    In sensory hair cells of the cochlea, deflection of the stereociliary bundle results in direct mechanical gating of mechanoelectrical transduction channels, a function generally attributed to the tip link running between the tips of short stereocilia and the sides of adjacent taller ones. However, immunocytochemical experiments indicate that the channels may not be associated with the tip link but occur just below it in a region of contact between the stereocilia. To determine whether transduction channels in this location could be operated during physiologically appropriate deflections as effectively by shear displacement as if they were associated with the tip link, a two dimensional kinematic analysis of relative motion between stereocilia has been performed assuming contact between stereocilia is maintained during deflection. Bundle geometry and dimensions were determined from transmission electron micrographs of hair cells from several frequency locations between 0.27 and 13.00 kHz in the guinea-pig cochlea. The analysis indicates that for a 10 nm deflection of the tallest stereocilia of both inner and outer hair cells, i.e. within the range of the maximum sensitivity of mammalian hair bundles, the average shear displacement in the contact region would be 1.6 nm, but that it increases systematically towards higher frequency regions for outer hair cells. This displacement is comparable in magnitude to tip-link elongation for individual stereociliary pairs.

    View details for Web of Science ID A1997WF62400007

    View details for PubMedID 9061959

  • Mechanical properties of the lateral cortex of mammalian auditory outer hair cells BIOPHYSICAL JOURNAL Tolomeo, J. A., Steele, C. R., Holley, M. C. 1996; 71 (1): 421-429

    Abstract

    Mammalian auditory outer hair cells generate high-frequency mechanical forces that enhance sound-induced displacements of the basilar membrane within the inner ear. It has been proposed that the resulting cell deformation is directed along the longitudinal axis of the cell by the cortical cytoskeleton. We have tested this proposal by making direct mechanical measurements on outer hair cells. The resultant stiffness modulus along the axis of whole dissociated cells was 3 x 10(-3) N/m, consistent with previously published values. The resultant axial and circumferential stiffness moduli for the cortical lattice were 5 x 10(-4) N/m and 3 x 10(-3) N/m, respectively. Thus the cortical lattice is a highly orthotropic structure. Its axial stiffness is small compared with that of the intact cell, but its circumferential stiffness is within the same order of magnitude. These measurements support the theory that the cortical cytoskeleton directs electrically driven length changes along the longitudinal axis of the cell. The Young's modulus of the circumferential filamentous components of the lattice were calculated to be 1 x 10(7) N/m2. The axial cross-links, believed to be a form of spectrin, were calculated to have a Young's modulus of 3 x 10(6) N/m2. Based on the measured values for the lattice and intact cell cortex, an estimate for the resultant stiffness modulus of the plasma membrane was estimated to be on the order of 10(-3) N/m. Thus, the plasma membrane appears to be relatively stiff and may be the dominant contributor to the axial stiffness of the intact cell.

    View details for Web of Science ID A1996UV90800045

    View details for PubMedID 8804625

  • Phyllotactic patterns: A biophysical mechanism for their origin ANNALS OF BOTANY Green, P. B., Steele, C. S., Rennich, S. C. 1996; 77 (5): 515-527
  • Noninvasive determination of bone mechanical properties using vibration response: A refined model and validation in vivo JOURNAL OF BIOMECHANICS Roberts, S. G., Hutchinson, T. M., Arnaud, S. B., Kiratli, B. J., MARTIN, R. B., Steele, C. R. 1996; 29 (1): 91-98

    Abstract

    Accurate non-invasive mechanical measurement of long bones is made difficult by the masking effect of surrounding soft tissues. Mechanical response tissue analysis (MRTA) offers a method for separating the effects of the soft tissue and bone; however, a direct validation has been lacking. A theoretical analysis of wave propagation through the compressed tissue revealed a strong mass effect dependent on the relative accelerations of the probe and bone. The previous mathematical model of the bone and overlying tissue system was reconfigured to incorporate the theoretical finding. This newer model (six-parameter) was used to interpret results using MRTA to determine bone cross-sectional bending stiffness, EIMRTA. The relationship between EIMRTA and theoretical EI values for padded aluminum rods was R2 = 0.999. A biological validation followed using monkey tibias. Each bone was tested in vivo with the MRTA instrument. Postmortem, the same tibias were excised and tested to failure in three-point bending to determine EI3-PT and maximum load. Diaphyseal bone mineral density (BMD) measurements were also made. The relationship between EI3-PT and in vivo EIMRTA using the six-parameter model is strong (R2 = 0.947) and better than that using the older model (R2 = 0.645). EIMRTA and BMD are also highly correlated (R2 = 0.853). MRTA measurements in vivo and BMD ex vivo are both good predictors of scaled maximum strength (R2 = 0.915 and R2 = 0.894, respectively). This is the first biological validation of a non-invasive mechanical measurement of bone by comparison to actual values. The MRTA technique has potential clinical value for assessing long-bone mechanical properties.

    View details for Web of Science ID A1996TM44400011

    View details for PubMedID 8839021

  • STEREOTYPE THREAT AND THE INTELLECTUAL TEST-PERFORMANCE OF AFRICAN-AMERICANS JOURNAL OF PERSONALITY AND SOCIAL PSYCHOLOGY Steele, C. M., Aronson, J. 1995; 69 (5): 797-811

    Abstract

    Stereotype threat is being at risk of confirming, as self-characteristic, a negative stereotype about one's group. Studies 1 and 2 varied the stereotype vulnerability of Black participants taking a difficult verbal test by varying whether or not their performance was ostensibly diagnostic of ability, and thus, whether or not they were at risk of fulfilling the racial stereotype about their intellectual ability. Reflecting the pressure of this vulnerability, Blacks underperformed in relation to Whites in the ability-diagnostic condition but not in the nondiagnostic condition (with Scholastic Aptitude Tests controlled). Study 3 validated that ability-diagnosticity cognitively activated the racial stereotype in these participants and motivated them not to conform to it, or to be judged by it. Study 4 showed that mere salience of the stereotype could impair Blacks' performance even when the test was not ability diagnostic. The role of stereotype vulnerability in the standardized test performance of ability-stigmatized groups is discussed.

    View details for Web of Science ID A1995TC10400001

    View details for PubMedID 7473032

  • ORTHOTROPIC PIEZOELECTRIC PROPERTIES OF THE COCHLEAR OUTER HAIR CELL-WALL JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Tolomeo, J. A., Steele, C. R. 1995; 97 (5): 3006-3011

    Abstract

    The mammalian outer hair cell has been shown to possess significant coupling between mechanical and electrical properties. This electromotile property may play a key role in cochlear tuning. In order to characterize quantitatively the electrical and mechanical behavior, the cell wall is modeled as a thin linear elastic piezoelectric material. Experimental findings from several investigators are used to determine the mechanical and electrical generalized stiffness coefficients described by the model. The model analysis indicates that orthotropic mechanical properties in the plane of the cell wall are required to match experimental behavior. The calculated orthotropic coefficients predict that the outer hair cell deforms due to cilia deflection with a force gain of 0.5 for perfectly constrained end conditions and a displacement gain of 3.6 for free end conditions. These values reflect the potential role of the OHC as a feedback mechanism to the basilar membrane. Results are for small deformation and quasi-static conditions with viscosity and inertial effects neglected. It is further assumed that cell permeability is negligible at the time scale of the fast deformation considered here.

    View details for Web of Science ID A1995QY60100039

    View details for PubMedID 7601982

  • DYNAMIC ANALYSIS OF SHELLS SHOCK AND VIBRATION Steele, C. R., Tolomeo, J. A., ZETES, D. E. 1995; 2 (5): 413-426
  • FOURIER-SERIES FOR POLYGONAL PLATE-BENDING - A VERY LARGE PLATE ELEMENT APPLIED MATHEMATICS AND COMPUTATION Kang, L. C., Wu, C. H., Steele, C. R. 1995; 67 (1-3): 197-225
  • SELF-IMAGE RESILIENCE AND DISSONANCE - THE ROLE OF AFFIRMATIONAL RESOURCES JOURNAL OF PERSONALITY AND SOCIAL PSYCHOLOGY Steele, C. M., Spencer, S. J., Lynch, M. 1993; 64 (6): 885-896

    Abstract

    It was predicted that high self-esteem Ss (HSEs) would rationalize an esteem-threatening decision less than low self-esteem Ss (LSEs), because HSEs presumably had more favorable self-concepts with which to affirm, and thus repair, their overall sense of self-integrity. This prediction was supported in 2 experiments within the "free-choice" dissonance paradigm--one that manipulated self-esteem through personality feedback and the other that varied it through selection of HSEs and LSEs, but only when Ss were made to focus on their self-concepts. A 3rd experiment countered an alternative explanation of the results in terms of mood effects that may have accompanied the experimental manipulations. The results were discussed in terms of the following: (a) their support for a resources theory of individual differences in resilience to self-image threats--an extension of self-affirmation theory, (b) their implications for self-esteem functioning, and (c) their implications for the continuing debate over self-enhancement versus self-consistency motivation.

    View details for Web of Science ID A1993LE94100001

    View details for PubMedID 8326471

  • INFLUENCE OF RECREATIONAL ACTIVITY AND MUSCLE STRENGTH ON ULNAR BENDING STIFFNESS IN MEN MEDICINE AND SCIENCE IN SPORTS AND EXERCISE Myburgh, K. H., Charette, S., Zhou, L. J., Steele, C. R., Arnaud, S., Marcus, R. 1993; 25 (5): 592-596

    Abstract

    Bone bending stiffness (modulus of elasticity [E] x moment of inertia [I]), a measure of bone strength, is related to its mineral content (BMC) and geometry and may be influenced by exercise. We evaluated the relationship of habitual recreational exercise and muscle strength to ulnar EI, width, and BMC in 51 healthy men, 28-61 yr of age. BMC and width were measured by single photon absorptiometry and EI by mechanical resistance tissue analysis. Maximum biceps strength was determined dynamically (1-RM) and grip strength isometrically. Subjects were classified as sedentary (S) (N = 13), moderately (M) (N = 18), or highly active (H) (N = 20) and exercised 0.2 +/- 0.2; 2.2 +/- 1.3; and 6.8 +/- 2.3 h.wk-1 (P < 0.001). H had greater biceps (P < 0.0005) and grip strength (P < 0.05), ulnar BMC (P < 0.05), and ulnar EI (P = 0.01) than M or S, who were similar. Amount of activity correlated with grip and biceps strength (r = 0.47 and 0.49; P < 0.001), but not with bone measurements, whereas muscle strength correlated with both EI and BMC (r = 0.40-0.52, P < 0.005). EI also correlated significantly with both BMC and ulnar width (P < 0.0001). Ulnar width and biceps strength were the only independent predictors of EI (r2 = 0.67, P < 0.0001). We conclude that levels of physical activity sufficient to increase arm strength influence ulnar bending stiffness.

    View details for Web of Science ID A1993LA33300009

    View details for PubMedID 8492687

  • INVIVO ASSESSMENT OF FOREARM BONE MASS AND ULNAR BENDING STIFFNESS IN HEALTHY-MEN JOURNAL OF BONE AND MINERAL RESEARCH Myburgh, K. H., Zhou, L. J., Steele, C. R., Arnaud, S., Marcus, R. 1992; 7 (11): 1345-1350

    Abstract

    The cross-sectional bending stiffness EI of the ulna was measured in vivo by mechanical resistance tissue analysis (MRTA) in 90 men aged 19-89 years. MRTA measures the impedance response of low-frequency vibrations to determine EI, which is a reflection of elastic modulus E and moment of inertia I for the whole ulna. EI was compared to conventional estimates of bone mineral content (BMC), bone width (BW), and BMC/BW, which were all measured by single-photon absorptiometry. Results obtained from the nondominant ulna indicate that BW increases (r = 0.27, p = 0.01) and ulnar BMC/BW decreases (r = -0.31, p < or = 0.005) with age. Neither BMC nor EI declined with age. The single best predictor of EI was BW (r2 = 0.47, p = 0.0001), and further small but significant contributions were made by BMC (r2 = 0.53, p = 0.0001) and grip strength (r2 = 0.55, p = 0.0001). These results suggest that the resistance of older men to forearm fracture is related to age-associated changes in the moment of inertia achieved by redistributing bone mineral farther from the bending axis. We conclude that the in vivo assessment of bone geometry offers important insights to the comprehensive evaluation of bone strength.

    View details for Web of Science ID A1992JY18200014

    View details for PubMedID 1466258

  • MODIFIED MIXED VARIATIONAL PRINCIPLE AND THE STATE-VECTOR EQUATION FOR ELASTIC BODIES AND SHELLS OF REVOLUTION JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME Steele, C. R., Kim, Y. Y. 1992; 59 (3): 587-595
  • A SOLUTION PROCEDURE FOR LAPLACE EQUATION ON MULTIPLY CONNECTED CIRCULAR DOMAINS JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME Bird, M. D., Steele, C. R. 1992; 59 (2): 398-404
  • STATIC AXISYMMETRICAL END PROBLEMS IN SEMI-INFINITE AND FINITE SOLID CYLINDERS JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME Kim, Y. Y., Steele, C. R. 1992; 59 (1): 69-76
  • HERMANN,GEORGE 70TH ANNIVERSARY ISSUE - PREFACE INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES NEMATNASSER, S., Steele, C. R. 1992; 29 (14-15): 1681-?
  • NONINVASIVE ASSESSMENT OF ULNAR BENDING STIFFNESS IN WOMEN JOURNAL OF BONE AND MINERAL RESEARCH McCabe, F., Zhou, L. J., Steele, C. R., Marcus, R. 1991; 6 (1): 53-59

    Abstract

    The load-carrying capacity of cortical bone is closely related to its geometry and to its fundamental material properties, including mineral content (BMC). Together these determine the bending stiffness EI, where I is the cross-sectional moment of inertia and E is Young's modulus of elasticity. To assess the relationship of BMC and bone width (BW) to EI in healthy women, we used mechanical response tissue analysis (MRTA), a noninvasive method that involves analysis of tissue responses to ulnar vibration. A total of 48 healthy women were enrolled into an older (64 +/- 1y, n = 25) and a younger (25 +/- 0.6y, n = 23) group. BMC and BW of the dominant ulna were measured by single-photon absorptiometry (SPA). EI was determined by MRTA. BMC (0.75 +/- 0.02 versus 0.63 +/- 0.02 g/cm), BMC/BW (0.75 +/- 0.02 versus 0.63 +/- 0.02 g/cm2), and EI (27.7 +/- 1.3 versus 21.3 +/- 1.1 N.m2) were significantly greater (p less than 0.005) in the young subjects. BW did not change with age (1.00 +/- 0.01 versus 1.01 +/- 0.01 cm). In young women, simple correlations of BMC and BW with EI were both significant. By multiple regression analysis only BW independently predicted EI (EI = -0.35 + 39.1 x BMC, R2 = 0.52). In older women BMC and BW correlated with EI, but in multiple regression only BMC was significant (EI = -34.5 + 62.1 x BW; R2 = 0.45). When this analysis of older women included only those whose BMC values were within 2 SD of the young mean, BMC remained the only significant predictor of EI.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for Web of Science ID A1991EU48800008

    View details for PubMedID 2048432

  • MODIFICATIONS OF SERIES EXPANSIONS FOR GENERAL END CONDITIONS AND CORNER SINGULARITIES ON THE SEMI-INFINITE STRIP JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME Kim, Y. Y., Steele, C. R. 1990; 57 (3): 581-588
  • AN ANALYTIC ASYMPTOTIC APPROACH FOR TIME-HARMONIC NONSYMMETRIC WAVE-PROPAGATION IN A CYLINDER INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES Kim, Y. Y., Steele, C. R. 1990; 26 (9-10): 1143-1157
  • Effects of Lateral Surface Conditions in Time-Harmonic Nonsymmetric Wave Propagation in a Cylinder JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME Kim, Y. Y., Steele, C. R. 1989; 56 (4): 910-917
  • End Effects and Time-Harmonic Longitudinal Wave Propagation in a Semi-Infinite Solid Cylinder JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME Kim, Y. Y., Steele, C. R. 1989; 56 (2): 334-346

    View details for DOI 10.1115/1.3176088

    View details for Web of Science ID 000207978600016

  • NONINVASIVE DETERMINATION OF ULNAR STIFFNESS FROM MECHANICAL RESPONSE - INVIVO COMPARISON OF STIFFNESS AND BONE-MINERAL CONTENT IN HUMANS JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME Steele, C. R., Zhou, L. J., Guido, D., Marcus, R., Heinrichs, W. L., Cheema, C. 1988; 110 (2): 87-96

    Abstract

    An approach referred to as Mechanical Response Tissue Analysis (MRTA) has been developed for the noninvasive determination of mechanical properties of the constituents of the intact limb. Of specific interest in the present study is the bending stiffness of the ulna. The point mechanical impedance properties in the low frequency regime, between 60 and 1,600 Hz are used. The procedure requires a proper design of the probe for good contact of the skin at midshaft and proper support of the proximal and distal ends of the forearm to obtain an approximation to "simple support" of the ulna. A seven-parameter model for the mechanical response is then valid, which includes the first mode of anterior-posterior beam bending of the ulna, the damping and spring effect of the soft tissue between probe and bone, and the damping of musculature. A dynamic analyzer (HP3562A) provides in seconds the impedance curve and the pole-zero curve fit. The physical parameters are obtained from a closed-form solution in terms of the curve-fit parameters. The procedure is automated and is robust and analytically reliable at about the five percent level. Some 80 human subjects have been evaluated by this mechanical response system and by the Norland single photon absorptiometer, providing for the first time in vivo, a comparison of elastic bending stiffness (ulna) and bone mineral content (radius). Three functional parameters of potential clinical value are the cross-sectional bending stiffness EI, the axial load capability Pcr (Euler buckling load) and the bone "sufficiency" S, defined as the ratio of Pcr to body weight. The correlation between EI and bone mineral (r = 0.81) is only slightly less than previous in vitro results with both measurements on the same bone (r = 0.89). When sufficiency is taken into consideration, the correlation of Pcr and bone mineral content is improved (r = 0.89). An implication is that "quality" of bone is a factor which is not indicated by bone mineral content but which is indicated by stiffness. Bone mineral is necessary for proper stiffness but not sufficient. Therefore mechanical measurement should provide a new dimension to be used toward a better understanding of the factors related to bone health and disease.

    View details for Web of Science ID A1988N541000001

    View details for PubMedID 3379938

  • INFLUENCE OF PHYSICAL-ACTIVITY ON THE REGULATION OF BONE-DENSITY JOURNAL OF BIOMECHANICS Whalen, R. T., Carter, D. R., Steele, C. R. 1988; 21 (10): 825-837

    Abstract

    Using a mathematical model which relates bone density to daily stress histories, the influence of physical activities on the apparent density of the calcaneal cancellous bone was investigated. Assuming that the mechanical bone maintenance stimulus is constant for all bone tissue, bone apparent density was calculated by a linear superposition of the mechanical stimulus provided by different daily physical activities. An empirical weighting factor, m, accounted for possible differences in the relative importance of load magnitude and number of cycles in each activity. By considering hypothetical variations in body weight and occupational activity levels, the range of probable m values was established. The model was then applied to the results of two previous running studies in which calcaneal density was measured to obtain an estimate of the stress exponent parameter, m. The results indicate that stress magnitudes (or joint forces) have a greater influence on bone mass than the number of loading cycles. We demonstrate that by carefully considering the magnitudes of imposed skeletal forces and the number of loading cycles, it may be possible to design exercise programs to achieve predictable changes in bone mass.

    View details for Web of Science ID A1988Q581200005

    View details for PubMedID 3225269

  • ELECTROKINETIC MODEL OF COCHLEAR HAIR CELL MOTILITY JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA JEN, D. H., Steele, C. R. 1987; 82 (5): 1667-1678

    Abstract

    Recent experiments have shown that isolated outer hair cells of the cochlea can vibrate under the influence of a transcellular oscillating electric field. Since high voltages have been measured in the cochlea, this result might suggest a basis for electromechanical feedback. A mechanical model of the hair cell has been developed and adapted to test the electrokinetic theory of motility, a postulate of which is that cochlear voltage gradients act on charged proteins embedded in the cell membrane to deform the cell. From the model it was deduced that the amount of charge density required is within the physiologic range. The significant result is that the amplitude of cell elongation for a fixed voltage amplitude is virtually constant for frequency less than a certain cutoff. The value of this frequency depends on the various physical parameters of the system and especially on the spacing between cells. Power transfer to the basilar membrane appears to peak near the cutoff frequency, and the amount is not very dependent on cell length, but is highly dependent on cell spacing.

    View details for Web of Science ID A1987K764800020

    View details for PubMedID 3693708

  • RAY SOLUTIONS ON SURFACES OF REVOLUTION JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME CHIEN, L. S., Steele, C. R. 1987; 54 (1): 151-158
  • ASYMPTOTIC SOLUTIONS FOR WARPING AND DISTORTION OF THIN-WALLED BOX BEAMS JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME BALCH, C. D., Steele, C. R. 1987; 54 (1): 165-173
  • AN EFFICIENT COMPUTATIONAL APPROACH FOR A LARGE OPENING IN A CYLINDRICAL VESSEL JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME Steele, C. R., Steele, M. L., KHATHLAN, A. 1986; 108 (4): 436-442
  • EFFECT OF OPENING AND DRAINING THE COCHLEA JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Steele, C. R., ZAIS, J. G. 1985; 78 (1): 84-89

    Abstract

    The WKB approximation was used in calculations of the pure-tone response of a two-dimensional inviscid model of the human cochlea and a three-dimensional inviscid model of the guinea pig cochlea. The common experimental procedure of opening the scala tympani was simulated. Basilar membrane displacement was unaffected at and beyond the peak, but was slightly lower pre-peak. The peak location shifted to a significant extent apically only when the fluid level in the scala tympani was lowered to less than 1/10 of normal depth.

    View details for Web of Science ID A1985ALW1300012

    View details for PubMedID 4019911

  • EFFECT OF COILING IN A COCHLEAR MODEL JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Steele, C. R., ZAIS, J. G. 1985; 77 (5): 1849-1852

    Abstract

    Transformation of the three-dimensional equations of fluid motion into cylindrical coordinates allowed analysis of a coiled cochlear model by the WKB technique. The model includes a single transverse mode of basilar membrane deflection and inviscid fluid. The results calculated using realistic parameters for the guinea pig show no significant difference in the basilar membrane amplitude and phase between the straight and coiled models. Some differences exist in the fluid pressure found in the scala. The conclusion is that the macromechanical response is not significantly affected by coiling.

    View details for Web of Science ID A1985AGS1600027

    View details for PubMedID 3998295

  • SURFACE DEFLECTION DUE TO THE PRESENCE OF A CRACK IN A HALF-SPACE APPLIED PHYSICS LETTERS Steele, C. R., Yoo, S. H. 1984; 44 (9): 857-859
  • STRESS-ANALYSIS OF NOZZLES IN CYLINDRICAL VESSELS WITH EXTERNAL LOAD JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME Steele, C. R., Steele, M. L. 1983; 105 (3): 191-200
  • TIBIAL CHANGES IN EXPERIMENTAL DISUSE OSTEOPOROSIS IN THE MONKEY CALCIFIED TISSUE INTERNATIONAL Young, D. R., NIKLOWITZ, W. J., Steele, C. R. 1983; 35 (3): 304-308

    Abstract

    We studied the mechanical properties and structural changes in the monkey tibia with disuse osteoporosis and during subsequent recovery. Bone bending stiffness was evaluated in relationship to microscopic changes in cortical bone and Norland bone mineral analysis. Restraint in the semireclined position produced regional losses of bone most obviously in the anterior-proximal tibiae. Following 6 months of restraint, the greatest losses of bone mineral in the proximal tibiae ranged from 23% to 31%; the largest changes in bone stiffness ranged from 36% to 40%. Approximately 8 1/2 months of recovery were required for restoration of normal bending properties. However, even after 15 months of recovery, bone mineral content did not necessarily return to normal levels. Histologically, resorption cavities in cortical bone were seen within 1 month of restraint; by 2 1/2 months of restraint there were large resorption cavities subperiosteally, endosteally, and intracortically. After 15 months of recovery, the cortex consisted mainly of first-generation haversian systems. After 40 months, the cortex appeared normal with numerous secondary and tertiary generations of haversian systems.

    View details for Web of Science ID A1983QQ97300009

    View details for PubMedID 6871761

  • COCHLEAR MODEL INCLUDING 3-DIMENSIONAL FLUID AND 4 MODES OF PARTITION FLEXIBILITY JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Taber, L. A., Steele, C. R. 1981; 70 (2): 426-436

    Abstract

    The WKB solution is developed for the analysis of a straight box cochlear model which includes four modes of partition displacement, simulating the motion of the bony shelf and arches of Corti, as well as the pectinate zone of the basilar membrane. The theory is similar to that previously used for the 1-mode model with scalar quantities now replaced by 4-vectors. Calculations are carried out for the guinea pig cochlea with stiffness computed mainly from the anatomy and assumed physiological values for the materials. Results show that the stiffness is such that the amplitude and phase of the basilar membrane response are not significantly altered from those given by the 1-mode model. For primates and some other mammals, the bony shelf is substantially weaker than in the guinea pig and causes a much more rapid accumulation of phase along the basilar membrane. Thus, with anatomically and physiologically consistent parameters, the model yields good correlation in phase and amplitude with the in vivo measurements which have been made in the squirrel monkey by Rhode [J. Acoust. Soc. Am. 64, 158-176 (1978)] as well as in the guinea pig by Wilson and Johnstone [J. Acoust. Soc. Am. 57, 705-723 (1975)] and Rhode [Basic Mechanisms in Hearing (Academic, New York, 1973), pp. 49-63].

    View details for Web of Science ID A1981MB22900015

    View details for PubMedID 7288028

  • 3-DIMENSIONAL MODEL-CALCULATIONS FOR GUINEA-PIG COCHLEA JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Steele, C. R., Taber, L. A. 1981; 69 (4): 1107-1111

    Abstract

    The WKB approximation was used for calculations of the pure tone response of a straight box model of the guinea pig cochlea with square scale cross sections and the fluid density and viscosity of water. Only one mode of elastic deformation of the partition was considered, corresponding to a flexible pectinate zone of the basilar membrane (BM) with rigid bony shelf, arches, and spiral ligament. Four distributions of pectinate zone transverse bending stiffness were considered, corresponding to volume compliances: (1) CB, measured by Békésy in the guinea pig post mortem, (2) CB/4, (3) CPL, deduced from Békésy's point load measurements in a human, with BM thickness inversely proportional to the width and rescaled for the guinea pig, and (4) 10CPL. We also considered various values of the relative longitudinal stiffness of the basilar membrane and the condition of drained or filled scala tympani. When compared to in vivo and post-mortem measurements of the guinea pig, the model results lead to the conjecture that the transverse fibers of the basilar membrane decrease in stiffness with time post mortem, while the ground substance increases in stiffness. Calculations using the compliance CB/4, with the ST drained with zero longitudinal BM stiffness give a response similar in location, peak shape, and phase to the in vivo capacitance probe measurements of Wilson and Johnstone [J., Acoust. Soc. Am 57, 705--23 (1975)]. Calculations for the ST filled and closed show a BM amplitude similar in location and shape to the spiral ganglion cell threshold curves obtained by Robertson and Johnstone [J. Acoust. Soc. Am. 57, 466--469 (1979)] from abnormal cochleas without outer hair cells. This indicates that the normal peak neural stimulation occurs about 1 mm apical of the BM peak amplitude. Naturally, the discrepancies between the postulated physical model and the cochlea prevent firm conclusions about cochlear function.

    View details for Web of Science ID A1981LK63600029

    View details for PubMedID 7229198

  • ASYMPTOTIC INTEGRATION METHODS APPLIED TO ROTATING BEAMS JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME Steele, C. R., Barry, K. E. 1980; 47 (4): 884-890
  • AN IMPROVED WKB CALCULATION FOR A TWO-DIMENSIONAL COCHLEAR MODEL JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Steele, C. R., Miller, C. E. 1980; 68 (1): 147-148

    Abstract

    The finite difference calculations of Neely [E.D. thesis, California Institute of Technology, Pasadena, CA (1977)] and the WKB solution of Steele and Taber [J. Acoust. Soc. Am. 65, 1001-1006 (1979)] generally agree, except in the "phase plateau" region, where both are irregular. In the present work, an improvement in the accuracy of the WKB procedure is gained by using a closed-form integral which gives the phase and damping functions in the short wavelength region. The present results agree qualitatively with the preceding but show a smooth variation with frequency and distance along the cochlea.

    View details for Web of Science ID A1980JZ60300021

    View details for PubMedID 7391356

  • NON-LINEAR CORRECTIONS FOR EDGE BENDING OF SHELLS JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME RANJAN, G. V., Steele, C. R. 1980; 47 (4): 861-865
  • PERMEABILITY OF FLUID-FLOW THROUGH HAIR CELL CILIA JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Frommer, G. H., Steele, C. R. 1979; 65 (3): 759-764
  • COMPARISON OF WKB CALCULATIONS AND EXPERIMENTAL RESULTS FOR 3-DIMENSIONAL COCHLEAR MODELS JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Steele, C. R., Taber, L. A. 1979; 65 (4): 1007-1018

    Abstract

    The WKB asymptotic method is applied to the calculation of cochlear models with square scala cross section, for which the fluid motion is fully three dimensional. The analysis begins with the exact solution for wave propagation in a duct with constant properties. This solution is somewhat tedious but straightforward, since it requires a Fourier series expansion across the duct. Then with the formulation of Whitham [Linear and Nonlinear Waves (Wiley, New York, 1974)], the approximate solution is readily generated for the duct with properties which vary slowly along the length. Numerical calculations are carried out for the experimental models of Cannel [Ph.D. thesis, Univ. of Warwick (1969)] and Helle [Dr.-Ing. disser., Technische Univ., Müchen (1974)] who furnish quantitative details of both "basilar membrane" response and model parameters. Without any free parameters for adjusting, the present WKB solution shows quite satisfactory agreement with the experimental model results. Computer time is reasonable; the calculation of displacement envelope and phase at a number of stations along the cochlea for a given frequency requires only one second of CPU time. Thus the credibility and practically of the approach is established for the investigation of yet more realistic and more elaborate cochlear models.

    View details for Web of Science ID A1979GU45700019

    View details for PubMedID 447914

  • ACOUSTOELASTIC IMAGING OF STRESS-FIELDS JOURNAL OF APPLIED PHYSICS Kino, G. S., Hunter, J. B., Johnson, G. C., Selfridge, A. R., Barnett, D. M., Hermann, G., Steele, C. R. 1979; 50 (4): 2607-2613
  • NON-INVASIVE MEASURES OF BONE BENDING RIGIDITY IN THE MONKEY (M-NEMESTRINA) CALCIFIED TISSUE INTERNATIONAL Young, D. R., Howard, W. H., Cann, C., Steele, C. R. 1979; 27 (2): 109-115

    Abstract

    The in vivo bending rigidity and bone mineral content of monkey ulnae and tibiae were measured. Bending rigidity in the anteroposterior plane was measured by an impedance probe technique. Forced vibrations of the bones were induced with an electromechanical shaker, and force and velocity at the driving point were determined. The responses over the range of 100-250 Hz were utilized to compute the bending rigidity. Bone mineral content in the cross section was determined by a photon absorption technique. Seventeen male monkeys (Macaca nemestrina) weighing 6-14 kg were evaluated. Repeatability of the rigidity measures was 4%. Bone mineral content was measured with a precision of 3.5%. Bending rigidity was correlated with the mineral content of the cross section, r = 0.899. Two monkeys were evaluated during prolonged hypodynamic restraint. Restraint produced regional losses of bone most obviously in the proximal tibia. Local bone mineral content declines 17 to 24% and the average bending rigidity declines 12 to 22%. Changes in bones leading to a reduction in mineral content and stiffness are discussed.

    View details for Web of Science ID A1979GY68900005

    View details for PubMedID 110412

  • COMPARISON OF WKB AND FINITE-DIFFERENCE CALCULATIONS FOR A 2-DIMENSIONAL COCHLEAR MODEL JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Steele, C. R., Taber, L. A. 1979; 65 (4): 1001-1006

    Abstract

    There are many points of uncertainty in the subject of cochlear models. In this paper only the question of efficient computing methods is addressed. For the cochlear model with a one-dimensional approximation for the fluid motion, Zweig, Lipes, and Pierce [J. Acoust. Soc. Am. 59, 975-982 (1976)] have shown that the WKB method agrees well with a direct numerical integration. For the two-dimensional fluid model, Neely [E.D. thesis, California Institute of Technology, Pasadena, CA (1977)] has shown that a direct finite difference solution is an order of magnitude faster than the integral equation approach used by Allen [J. Acoust. Soc. Am 61, 110-119 (1977)]. In the present work, a formal WKB solution is derived following Whitham [Linear and Nonlinear Waves (Wiley, New York, 1974)]. The advantage of this formulation is simplicity, but the disadvantage is that no error estimate is available. We find that the numerical results from the WKB solution agree well with those of Neely (1977), while the computer time is reduced by another order of magnitude. Thus, the WKB method seems to offer the satisfactory accuracy, efficiency, and flexibility for treating the more realistic cochlear models.

    View details for Web of Science ID A1979GU45700018

    View details for PubMedID 447913

  • ACCURATE 3-DIMENSIONAL EYETRACKER APPLIED OPTICS CRANE, H. D., Steele, C. M. 1978; 17 (5): 691-705

    Abstract

    A combined optometer and eyetracking instrument has been developed to measure both the dynamic refractive power and the direction of gaze of the same eye. In effect, this instrument measures, as a function of time, the point in 3-D space on which the eye is fixated. Nothing is attached to the subject (patient), who is easily aligned in the device. The measuring wavelength is in the near ir and is invisible. The usable field of the instrument is greater than 20 degrees ; the horizontal and vertical directions of gaze are measured with a noise level and repeatability of about 1 min of arc. The range of the optometer is approximately -4 to +12 diopters; refractive power is measured to about 0.1 diopter. Two instruments may be aligned side by side for tracking both eyes simultaneously. Three-dimensional monocular and binocular eye movement records are shown.

    View details for Web of Science ID A1978EN24200011

    View details for PubMedID 20197858

  • BENDING WAVES IN SHELLS QUARTERLY OF APPLIED MATHEMATICS Steele, C. R. 1977; 34 (4): 385-392
  • ANALYSIS OF TORISPHERICAL PRESSURE-VESSELS JOURNAL OF THE ENGINEERING MECHANICS DIVISION-ASCE RANJAN, G. V., Steele, C. R. 1976; 102 (4): 643-657
  • ANALYSIS OF KNUCKLE REGION BETWEEN 2 SMOOTH SHELLS JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME RANJAN, G. V., Steele, C. R. 1975; 42 (4): 853-857
  • MEMBRANE SOLUTIONS FOR SHELLS WITH EDGE CONSTRAINT - CLOSURE JOURNAL OF THE ENGINEERING MECHANICS DIVISION-ASCE Steele, C. R. 1975; 101 (5): 710-710
  • PULSE-PROPAGATION IN INHOMOGENEOUS-MEDIA JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME LONGCOPE, D. B., Steele, C. R. 1974; 41 (4): 1057-1062
  • MEMBRANE SOLUTIONS FOR SHELLS WITH EDGE CONSTRAINT JOURNAL OF THE ENGINEERING MECHANICS DIVISION-ASCE Steele, C. R. 1974; 100 (NEM3): 497-510
  • ASYMPTOTIC SOLUTIONS FOR ORTHOTROPIC NONHOMOGENEOUS SHELLS OF REVOLUTION JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME FETTAHLI, O. A., Steele, C. R. 1974; 41 (3): 753-758
  • BEHAVIOR OF BASILAR-MEMBRANE WITH PURE-TONE EXCITATION JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Steele, C. R. 1974; 55 (1): 148-162

    View details for Web of Science ID A1974S237700021

    View details for PubMedID 4815753

  • STIFFNESS OF REISSNERS MEMBRANE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Steele, C. R. 1974; 56 (4): 1252-1257

    View details for Web of Science ID A1974U523700033

    View details for PubMedID 4420487