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Wichelhaus A, Guggenbühl S, Hötzel L, Seidel CL, Sabbagh H, Hoffmann L. Comparing Torque Transmission of Different Bracket Systems in Combination with Various Archwires Considering Play in the Bracket Slot: An In Vitro Study. Materials (Basel) 2024; 17:684. [PMID: 38591559 PMCID: PMC10856117 DOI: 10.3390/ma17030684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 04/10/2024]
Abstract
This study aims to examine the play between various archwires and bracket systems, exploring potential variations in angle values for specific torque and torque values for a given angle along different bracket systems. Therefore, seven brackets systems were evaluated in conjunction with different stainless steel archwires of varying dimensions (0.016″ × 0.022″, 0.018″ × 0.025″, and 0.019″ × 0.025″). Biomechanical behavior during torque development and transmission was assessed using a six-component force/torque sensor. Torque angles (5-45°) were specified with subsequent torque measurement, and the sequence was reversed by setting the torque (5-30 Nmm) and measuring the angle. A reference measurement with 0 Nmm torque served to evaluate bracket slot play. Bracket play (0 Nmm) during palatal load ranged between 20.06° and 32.50° for 0.016″ × 0.022″ wire, 12.83° and 21.11° for 0.018″ × 0.025″ wire, and 8.39° and 18.73° for 0.019″ × 0.025″ wire. The BioQuick® bracket exhibited the highest play, while Wave SL® and Damon® Q brackets demonstrated the lowest play (p < 0.001). Significant differences (p < 0.001) between the brackets were observed in the torque angles required to achieve torques of 5-20 Nmm. In summary, each bracket system has a different torque transmission, which is of great clinical importance in order to achieve correct torque transmission and avoid complications such as root resorption.
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Affiliation(s)
- Andrea Wichelhaus
- Department of Orthodontics and Dentofacial Orthopedics, University Hospital, LMU Munich, Goethestrasse 70, 80366 Munich, Germany; (A.W.); (L.H.); (C.L.S.); (H.S.)
| | - Simon Guggenbühl
- Orthodontia Private Practice, Engelbergstrasse 28a, 6370 Stans, Switzerland;
| | - Linus Hötzel
- Department of Orthodontics and Dentofacial Orthopedics, University Hospital, LMU Munich, Goethestrasse 70, 80366 Munich, Germany; (A.W.); (L.H.); (C.L.S.); (H.S.)
| | - Corinna L. Seidel
- Department of Orthodontics and Dentofacial Orthopedics, University Hospital, LMU Munich, Goethestrasse 70, 80366 Munich, Germany; (A.W.); (L.H.); (C.L.S.); (H.S.)
| | - Hisham Sabbagh
- Department of Orthodontics and Dentofacial Orthopedics, University Hospital, LMU Munich, Goethestrasse 70, 80366 Munich, Germany; (A.W.); (L.H.); (C.L.S.); (H.S.)
| | - Lea Hoffmann
- Department of Orthodontics and Dentofacial Orthopedics, University Hospital, LMU Munich, Goethestrasse 70, 80366 Munich, Germany; (A.W.); (L.H.); (C.L.S.); (H.S.)
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Damsgaard JB, Lauritzen J, Delmar C, Kvande ME. Beyond loss: An essay about presence and sparkling moments based on observations from life coexisting with a person living with dementia. Nurs Philos 2024; 25:e12425. [PMID: 36846929 DOI: 10.1111/nup.12425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 12/22/2022] [Accepted: 02/08/2023] [Indexed: 03/01/2023]
Abstract
This is an essay based on a story with observations, about present and sparkling moments from everyday life coexisting with a mother living with dementia. The story is used to begin philosophical underpinnings reflecting on 'how it could be otherwise'. Dementia deploys brutal existential experiences such as cognitive deterioration, decline in mental functioning and often hurtful social judgements. The person living with dementia goes through transformation and changes of self. Cognitive decline progressively disrupts the foundations upon which social connectedness is built, often creating a profound sense of insecurity. The challenge for carers and healthcare professionals is therefore to find ways of clarifying a concept of agency. It will be worthwhile developing the ability of attuning into 'what is there' arising from every corner of the care situation. Understanding and practicing this can strengthen existence and the experience of connectedness and meaning, empowering the person with dementia. It is important to find ways, relational moves, in which carers and healthcare professionals can embed the creativity appearing in mundane everyday situations filled with surplus of meaning, sharing mental landscapes (and embodied relational understanding) with the person living with dementia - seizing and sharing aesthetic moments (verbal and nonverbal) being present together. We argue that carers and healthcare professionals may find this understanding of care useful. This implies looking into a phenomenological-hermeneutic perspective developing competences as well as practical wisdom understanding and being aware of the creative and innovative possibilities (often preverbal and unnoticed small things) in everyday life of what we, inspired by psychoanalyst Daniel Stern, call sparkling moments of meeting, creating experience with the other that is personally undergone and lived through in the present.
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Affiliation(s)
- Janne B Damsgaard
- Department of Public Health, Nursing, Aarhus University, Aarhus, Denmark
| | - Jette Lauritzen
- Department of Public Health, Nursing, Aarhus University, Aarhus, Denmark
- VIA University College, Aarhus, Denmark
| | - Charlotte Delmar
- Department of Public Health, Nursing, Aarhus University, Aarhus, Denmark
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Burnett RA, Viano DC, Parenteau CS. Quasi-static methods to evaluate seat strength in rear impacts. Traffic Inj Prev 2022; 24:218-223. [PMID: 36383644 DOI: 10.1080/15389588.2022.2140280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/19/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
OBJECTIVE Various methods have been used in the past 50 years to apply Quasi-static load to a seat in the rear direction and measure seat performance in rear impacts. This study compared five of the most-common test procedures to evaluate seats. In addition, occupant mass and center of gravity are discussed as important characteristics of rear loading of seats. METHOD Data was collected and analyzed from five different seat pull tests, including FMVSS 207, modified FMVSS 207, QST, body block and FRED II. Test data included peak force, moment and angle at peak moment. Occupant loading height of was determined using body segment weights and position in the forward (x) and vertical (z) directions based on anthropometry data. RESULTS Some of the inherent differences in the tests are shown by comparing data with the same seat structure. The QST and FRED II use a lower height of loading than FMVSS 207. The QST and FRED II peak moment and force did not coincide with the same seatback angle as in FMVSS 207 and body block testing. Center of gravity height varies depending on whether the whole body or only the upper torso is considered. For the 50th male, it is 171.5 mm (6.8") with the whole body and 246.7 mm (9.7") with the upper torso. CONCLUSION Results from different tests cannot be readily compared because of different loading conditions, including body shape and height of load about the H-point, which can cause the seat structure to respond differently.
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Churchill RM, Werner MJ, Biggs J, Fagereng Å. Afterslip Moment Scaling and Variability From a Global Compilation of Estimates. J Geophys Res Solid Earth 2022; 127:e2021JB023897. [PMID: 35865712 PMCID: PMC9287082 DOI: 10.1029/2021jb023897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/22/2022] [Accepted: 04/02/2022] [Indexed: 05/26/2023]
Abstract
Aseismic afterslip is postseismic fault sliding that may significantly redistribute crustal stresses and drive aftershock sequences. Afterslip is typically modeled through geodetic observations of surface deformation on a case-by-case basis, thus questions of how and why the afterslip moment varies between earthquakes remain largely unaddressed. We compile 148 afterslip studies following 53 M w 6.0-9.1 earthquakes, and formally analyze a subset of 88 well-constrained kinematic models. Afterslip and coseismic moments scale near-linearly, with a median Spearman's rank correlation coefficient (CC) of 0.91 after bootstrapping (95% range: 0.89-0.93). We infer that afterslip area and average slip scale with coseismic moment as M o 2 / 3 and M o 1 / 3 , respectively. The ratio of afterslip to coseismic moment (M rel ) varies from <1% to >300% (interquartile range: 9%-32%). M rel weakly correlates with M o (CC: -0.21, attributed to a publication bias), rupture aspect ratio (CC: -0.31), and fault slip rate (CC: 0.26, treated as a proxy for fault maturity), indicating that these factors affect afterslip. M rel does not correlate with mainshock dip, rake, or depth. Given the power-law decay of afterslip, we expected studies that started earlier and spanned longer timescales to capture more afterslip, but M rel does not correlate with observation start time or duration. Because M rel estimates for a single earthquake can vary by an order of magnitude, we propose that modeling uncertainty currently presents a challenge for systematic afterslip analysis. Standardizing modeling practices may improve model comparability, and eventually allow for predictive afterslip models that account for mainshock and fault zone factors to be incorporated into aftershock hazard models.
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Affiliation(s)
| | - M. J. Werner
- School of Earth SciencesUniversity of BristolBristolUK
| | - J. Biggs
- School of Earth SciencesUniversity of BristolBristolUK
| | - Å. Fagereng
- School of Earth and Environmental SciencesCardiff UniversityCardiffUK
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Fava AW, Downs Talmage JL, Plummer HA, Oliver GD. Drive-Leg Kinematics During the Windup and Pushoff Is Associated With Pitching Kinetics at Later Phases of the Pitch. Am J Sports Med 2022; 50:1409-1415. [PMID: 35238687 DOI: 10.1177/03635465221077451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Inconsistent findings exist between drive-leg ground-reaction forces (GRFs) and pitching mechanics. Previous literature has largely reported drive-leg mechanics and GRFs at the start of the pushoff phase for their role in initiating force development. Little research has assessed drive-leg kinematics that includes a pitcher's windup motion to determine its effects on subsequent phases in the pitching motion. PURPOSE/HYPOTHESIS The primary aim was to analyze the relationship between drive-leg knee valgus angle during the windup and subsequent pitching mechanics. We hypothesized that the drive-leg knee valgus angle during the early portion of the pitching motion would alter later phases' pitching mechanics. A secondary aim was to assess GRFs to determine if the drive-leg knee valgus angle was associated with changes in force. We hypothesized that an increased drive-leg knee valgus angle would increase GRFs during the pitching motion. STUDY DESIGN Descriptive laboratory study. METHODS A total of 17 high school baseball pitchers (mean age, 16.1 ± 0.9 years; mean height, 180.0 ± 4.8 cm; mean weight, 75.5 ± 7.5 kg) volunteered for the study. Kinematic data and GRFs were collected using an electromagnetic tracking system and force plates. Pitchers threw maximal-effort fastballs from a mound at regulation distance. The drive-leg knee valgus angle was analyzed during the windup and pushoff phases of the pitch to determine its effects on other biomechanical variables throughout the pitching motion. RESULTS There was a significant relationship between drive-leg knee valgus angle during the windup (Fchange 1,12) = 16.13; P = .002; R2 = 0.695) and lateral GRF in the arm-cocking phase. Additionally, there was a significant relationship between drive-leg knee valgus angle during pushoff (Fchange(2,11) = 10.21; P = .003; R2 = 0.716) and lateral GRF in the arm-cocking phase and pitching-elbow valgus moment in the acceleration phase. CONCLUSION Drive-leg knee valgus angle during the windup and pushoff had a significant relationship with drive-leg GRF and pitching-elbow valgus moment at later stages of the pitching cycle. CLINICAL RELEVANCE Assessments of drive-leg kinematics during the windup and pushoff may be useful in identifying inefficient movement patterns that can have an effect on the direction of a pitcher's drive-leg force contribution, which can lead to increased forces on the throwing elbow.
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Affiliation(s)
- Anthony W Fava
- Sports Medicine and Movement Laboratory, School of Kinesiology, Auburn University, Auburn, Alabama, USA
| | - Jessica L Downs Talmage
- Sports Medicine and Movement Laboratory, School of Kinesiology, Auburn University, Auburn, Alabama, USA
| | - Hillary A Plummer
- United States Army Aeromedical Research Laboratory, Fort Rucker, Alabama, USA.,Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, USA
| | - Gretchen D Oliver
- Sports Medicine and Movement Laboratory, School of Kinesiology, Auburn University, Auburn, Alabama, USA
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Gotoh T, Yang J. Transition of fluctuations from Gaussian state to turbulent state. Philos Trans A Math Phys Eng Sci 2022; 380:20210097. [PMID: 35034486 PMCID: PMC8762345 DOI: 10.1098/rsta.2021.0097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 07/19/2021] [Indexed: 05/29/2023]
Abstract
Variation of the statistical properties of an incompressible velocity, passive vector and passive scalar in isotropic turbulence was studied using direct numerical simulation. The structure functions of the gradients, and the moments of the dissipation rates, began to increase at about [Formula: see text] from the Gaussian state and grew rapidly at [Formula: see text] in the turbulent state. A contour map of the probability density functions (PDFs) indicated that PDF expansion of the gradients of the passive vector and passive scalar begins at around [Formula: see text], whereas that of the longitudinal velocity gradient PDF is more gradual. The left tails of the dissipation rate PDF were found to follow a power law with an exponent of 3/2 for the incompressible velocity and passive vector dissipation rates, and 1/2 for the scalar dissipation rate and the enstrophy; they remained constant for all Reynolds numbers, indicating the universality of the left tail. The analytical PDFs of the dissipation rates and enstrophy of the Gaussian state were obtained and found to be the Gamma distribution. It was shown that the number of terms contributing to the dissipation rates and the enstrophy determines the decay rates of the two PDFs for low to moderate amplitudes. This article is part of the theme issue 'Scaling the turbulence edifice (part 1)'.
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Affiliation(s)
- Toshiyuki Gotoh
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso, Nagoya 466-8555, Japan
- Research and Education Center for Natural Sciences, Keio University, Hiyoshi, Yokohama 223-8521, Japan
| | - Jingyuan Yang
- Institute of Industry Technology, Guangzhou and Chinese Academy of Sciences, 1121 Haibin Road, Nansha Dis., Guangzhou City, People’s Republic of China
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Grimmer M, Elshamanhory AA, Beckerle P. Human Lower Limb Joint Biomechanics in Daily Life Activities: A Literature Based Requirement Analysis for Anthropomorphic Robot Design. Front Robot AI 2021; 7:13. [PMID: 33501182 PMCID: PMC7805781 DOI: 10.3389/frobt.2020.00013] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 01/21/2020] [Indexed: 01/09/2023] Open
Abstract
Daily human activity is characterized by a broad variety of movement tasks. This work summarizes the sagittal hip, knee, and ankle joint biomechanics for a broad range of daily movements, based on previously published literature, to identify requirements for robotic design. Maximum joint power, moment, angular velocity, and angular acceleration, as well as the movement-related range of motion and the mean absolute power were extracted, compared, and analyzed for essential and sportive movement tasks. We found that the full human range of motion is required to mimic human like performance and versatility. In general, sportive movements were found to exhibit the highest joint requirements in angular velocity, angular acceleration, moment, power, and mean absolute power. However, at the hip, essential movements, such as recovery, had comparable or even higher requirements. Further, we found that the moment and power demands were generally higher in stance, while the angular velocity and angular acceleration were mostly higher or equal in swing compared to stance for locomotion tasks. The extracted requirements provide a novel comprehensive overview that can help with the dimensioning of actuators enabling tailored assistance or rehabilitation for wearable lower limb robots, and to achieve essential, sportive or augmented performances that exceed natural human capabilities with humanoid robots.
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Affiliation(s)
- Martin Grimmer
- Lauflabor Locomotion Laboratory, Department of Human Sciences, Institute of Sports Science, Technische Universität Darmstadt, Darmstadt, Germany
| | | | - Philipp Beckerle
- Elastic Lightweight Robotics Group, Department of Electrical Engineering and Information Technology, Robotics Research Institute, Technische Universität Dortmund, Dortmund, Germany.,Institute for Mechatronic Systems, Mechanical Engineering, Technische Universität Darmstadt, Darmstadt, Germany
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Liu J, Xiao Y, Li M, Tao J, Xu S. Intermittency, Moments, and Friction Coefficient during the Subcritical Transition of Channel Flow. Entropy (Basel) 2020; 22:E1399. [PMID: 33322374 DOI: 10.3390/e22121399] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/01/2020] [Accepted: 12/08/2020] [Indexed: 11/17/2022]
Abstract
The intermittent distribution of localized turbulent structures is a key feature of the subcritical transitions in channel flows, which are studied in this paper with a wind channel and theoretical modeling. Entrance disturbances are introduced by small beads, and localized turbulent patches can be triggered at low Reynolds numbers (Re). High turbulence intensity represents strong ability of perturbation spread, and a maximum turbulence intensity is found for every test case as Re ≥ 950, where the turbulence fraction increases abruptly with Re. Skewness can reflect the velocity defects of localized turbulent patches and is revealed to become negative when Re is as low as about 660. It is shown that the third-order moments of the midplane streamwise velocities have minima, while the corresponding forth-order moments have maxima during the transition. These kinematic extremes and different variation scenarios of the friction coefficient during the transition are explained with an intermittent structure model, where the robust localized turbulent structure is simplified as a turbulence unit, a structure whose statistical properties are only weak functions of the Reynolds number.
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Perry SK, Buddhadev HH, Brilla LR, Suprak DN. Mechanical Demands at the Ankle Joint During Saut de Chat and Temps levé Jumps in Classically Trained Ballet Dancers. Open Access J Sports Med 2019; 10:191-197. [PMID: 31827337 PMCID: PMC6902839 DOI: 10.2147/oajsm.s234289] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 11/20/2019] [Indexed: 11/25/2022] Open
Abstract
Background During ballet, injuries to the Achilles tendon are associated with the take-off phase of various jumps. Research question The purpose of the study was to assess differences in mechanical demand on the body, specifically at the ankle, in two single-leg jumps commonly trained in ballet: a saut de chat (SDC) and a temps levé (TL). Methods Fifteen classically trained female dancers had 16 reflective markers placed on the lower body and each dancer performed each jump three times on a force plate. The marker position data and ground reaction forces (GRF) were captured synchronously at 250 Hz and 1000 Hz, respectively. Peak vertical GRF, mean rate of force development (RFD), peak ankle moment, and peak ankle power were determined and averaged across trials. Paired t-tests were used to determine differences between the SDC and the TL. Results When compared to the TL, the SDC displayed significantly higher peak vertical GRF (p = 0.003), RFD (p = 0.002), and peak ankle moment and power (p < 0.001). The effect sizes for these differences were large for all variables (Cohen’s d > 0.80). Conclusion The mechanical demand at the ankle joint is significantly greater for the SDC than the TL.
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Affiliation(s)
- Sarah K Perry
- Department of Health and Human Development, Western Washington University, Bellingham, WA, USA
| | - Harsh H Buddhadev
- Department of Health and Human Development, Western Washington University, Bellingham, WA, USA
| | - Lorraine R Brilla
- Department of Health and Human Development, Western Washington University, Bellingham, WA, USA
| | - David N Suprak
- Department of Health and Human Development, Western Washington University, Bellingham, WA, USA
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Iliadi A, Koletsi D, Eliades T. Forces and moments generated by aligner-type appliances for orthodontic tooth movement: A systematic review and meta-analysis. Orthod Craniofac Res 2019; 22:248-258. [PMID: 31237410 DOI: 10.1111/ocr.12333] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/19/2019] [Accepted: 06/20/2019] [Indexed: 12/27/2022]
Abstract
The aim of this review was to systematically appraise the evidence on aligner mechanics and forces and moments generated across difference types of aligners. In vitro- laboratory studies for model simulated tooth movement with aligners. Database searches within Medline via Pubmed, Cochrane Central Register of Controlled Trials (CENTRAL), LILACS via BIREME Virtual Health Library. Unpublished literature was also searched in Open Grey, ClinicalTrials.gov (www.clinicaltrials.gov), the National Research Register (www.controlled-trials.com) and Center for Open Science (Open Science Framework), using the terms "aligner" AND "orthodontic". Risk of bias assessment was based on the Cochrane Risk of Bias tool. Random effects meta-analyses were conducted. A total of 447 studies were identified through electronic search and after careful consideration of pre- defined eligibility criteria, 13 deemed eligible for inclusion, while 2 were included in the quantitative synthesis. When palatal tipping of the upper central incisor through PET-G aligners was considered, aligner thickness of 0.5, 0.625 or 0.75 mm was not associated with a significantly different moment to force (M/F) ratio, given a common gingival edge width of 3-4 mm. Aligner thickness does not appear to possess a significant role in forces and moments generated by clear aligners under specific settings, while the most commonly examined tooth movements are tipping and rotation. The findings of this review may be applicable to certain conditions in laboratory settings.
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Affiliation(s)
- Anna Iliadi
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Despina Koletsi
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.,Clinic of Orthodontics and Paediatric Dentistry, School of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Theodore Eliades
- Clinic of Orthodontics and Paediatric Dentistry, School of Dental Medicine, University of Zurich, Zurich, Switzerland
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Crisco JJ, Osvalds NJ, Rainbow MJ. The Kinetics of Swinging a Baseball Bat. J Appl Biomech 2018; 34:386-91. [PMID: 29651903 DOI: 10.1123/jab.2017-0337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The purpose of this study was to compute the 3-dimensional kinetics required to swing 3 youth baseball bats of varying moments of inertia. The 306 swings by 22 male players (age 13-18 y) were analyzed. Inverse dynamics with respect to the batter's hands were computed given the known kinematics and physical properties of the bats. Peak force increased with larger bat moments of inertia and was strongly correlated with bat tip speed. By contrast, peak moments were weakly correlated with bat moments of inertia and bat tip speed. Throughout the swing, the force applied to the bat was dominated by a component aligned with the long axis of the bat and directed away from the bat knob, whereas the moment applied to the bat was minimal until just prior to ball impact. These results indicate that players act to mostly "pull" the bat during their swing until just prior to ball impact, at which point they rapidly increase the moment on the bat. This kinetic analysis provides novel insight into the forces and moments used to swing baseball bats.
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Abstract
PURPOSE The technocratic and medicalized model of healthcare is rarely optimal for patients. By connecting two different studies we explore the possibilities of increasing quality of life in cancer care. METHODS The first study captures survival strategies in a historically isolated Arctic village in Norway resulting in Momentary contentment theory, which emerged from analysing four years of participant observation and interview data. The second study conceptualizes everyday life of cancer patients based on in-depth interviews with 19 cancer patients; this was conceptualized as Navigating a new life situation. Both studies used classic grounded theory methodology. The connection between the studies is based on a health design approach. RESULTS We found a fit between cancer patients challenging life conditions and harsh everyday life in an Arctic village. Death, treatments and dependence have become natural parts of life where the importance of creating spaces-of-moments and a Sense of Safety is imminent to well-being. While the cancer patients are in a new life situation, the Arctic people show a natural ability to handle uncertainties. CONCLUSION By innovation theories connected to design thinking, Momentary contentment theory modified to fit cancer care would eventually be a way to improve cancer patients' quality of life.
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Affiliation(s)
- Ulrika Sandén
- a Department of Design Sciences , Lund University , Lund , Sweden
| | - Lars Harrysson
- b School of Social work , Lund University , Lund , Sweden
| | - Hans Thulesius
- c Department of Clinical Sciences , Lund University , Malmö , Sweden
| | - Fredrik Nilsson
- a Department of Design Sciences , Lund University , Lund , Sweden
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Xie P, Zhao JY, Wu ZY, Sang YF, Chen J, Li BB, Gu HT. [Gene method for inconsistent hydrological frequency calculation. 2: Diagnosis system of hydrological genes and method of hydrological moment genes with inconsistent characters]. Ying Yong Sheng Tai Xue Bao 2018; 29:1033-1041. [PMID: 29726210 DOI: 10.13287/j.1001-9332.201804.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The analysis of inconsistent hydrological series is one of the major problems that should be solved for engineering hydrological calculation in changing environment. In this study, the diffe-rences of non-consistency and non-stationarity were analyzed from the perspective of composition of hydrological series. The inconsistent hydrological phenomena were generalized into hydrological processes with inheritance, variability and evolution characteristics or regulations. Furthermore, the hydrological genes were identified following the theory of biological genes, while their inheritance bases and variability bases were determined based on composition of hydrological series under diffe-rent time scales. To identify and test the components of hydrological genes, we constructed a diagnosis system of hydrological genes. With the P-3 distribution as an example, we described the process of construction and expression of the moment genes to illustrate the inheritance, variability and evolution principles of hydrological genes. With the annual minimum 1-month runoff series of Yunjinghong station in Lancangjiang River basin as an example, we verified the feasibility and practicability of hydrological gene theory for the calculation of inconsistent hydrological frequency. The results showed that the method could be used to reveal the evolution of inconsistent hydrological series. Therefore, it provided a new research pathway for engineering hydrological calculation in changing environment and an essential reference for the assessment of water security.
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Affiliation(s)
- Ping Xie
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China.,Collaborative Innovation Center for Territorial Sovereignty and Maritime Rights, Wuhan 430072, China
| | - Jiang Yan Zhao
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
| | - Zi Yi Wu
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
| | - Yan Fang Sang
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Chen
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
| | - Bin Bin Li
- Hydrological Bureau of Yangtze River Commission, Wuhan 430010, China
| | - Hai Ting Gu
- College of Civil Engineering Architecture, Zhejiang University, Hangzhou 310058, China
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Teng HL, Wu D, Su F, Pedoia V, Souza RB, Ma CB, Li X. Gait Characteristics Associated With a Greater Increase in Medial Knee Cartilage T 1ρ and T 2 Relaxation Times in Patients Undergoing Anterior Cruciate Ligament Reconstruction. Am J Sports Med 2017; 45:3262-3271. [PMID: 28898105 DOI: 10.1177/0363546517723007] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Osteoarthritis of the medial tibiofemoral joint (MTFJ) is prevalent among patients undergoing anterior cruciate ligament reconstruction (ACLR). Magnetic resonance T1ρ and T2 relaxation times provide noninvasive methods to quantify early cartilage degeneration. Altered sagittal-plane gait biomechanics have been observed after ACLR, but their associations with longitudinal changes in MTFJ cartilage T1ρ and T2 remain unclear. Hypothesis/Purpose: To examine whether the peak knee flexion moment (KFM), knee flexion angle (KFA), and vertical ground-reaction force (vGRF) during gait are associated with prospective changes in medial tibiofemoral cartilage T1ρ and T2 in ACL-reconstructed knees and to compare these gait characteristics between patients undergoing ACLR and healthy control participants. We hypothesized that a higher KFM, KFA, and vGRF would be associated with greater increases in cartilage relaxation times and that patients undergoing ACLR would demonstrate altered gait characteristics compared with healthy controls. STUDY DESIGN Controlled laboratory study. METHODS Thirty-three patients undergoing ACLR underwent gait analysis before and 6 months and 1 year after ACLR and knee magnetic resonance imaging (MRI) before and 6 months, 1 year, and 2 years after ACLR. Twelve healthy controls underwent knee MRI and gait analysis at baseline and 1 year. Cartilage T1ρ and T2 were calculated for the medial tibia and medial femoral condyle. Linear regressions were used to evaluate associations between gait characteristics and changes in cartilage relaxation times from before ACLR to follow-up time points. Independent t tests were used to compare differences in gait between patients undergoing ACLR and control participants. RESULTS A higher KFM and KFA before ACLR were related to greater increases in medial femoral condyle T1ρ and T2 at 6 months after ACLR. Similarly, a higher KFM, KFA, and vGRF at 6 months were associated with greater increases in medial tibia and medial femoral condyle T1ρ and T2 at 1 and 2 years after ACLR. Gait characteristics at 1 year were not associated with changes in cartilage relaxation times at 2 years after ACLR. Compared with healthy controls, patients undergoing ACLR demonstrated a lower KFM at 6 months after ACLR. CONCLUSION/CLINICAL RELEVANCE The findings of this study revealed that a higher KFM, KFA, and vGRF during gait, especially at 6 months after ACLR, were associated with greater deterioration of MTFJ cartilage health at later time points.
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Affiliation(s)
- Hsiang-Ling Teng
- Musculoskeletal and Quantitative Imaging Research, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.,Department of Physical Therapy, California State University, Long Beach, Long Beach, California, USA
| | - Daniel Wu
- Musculoskeletal and Quantitative Imaging Research, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Favian Su
- Musculoskeletal and Quantitative Imaging Research, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Valentina Pedoia
- Musculoskeletal and Quantitative Imaging Research, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Richard B Souza
- Musculoskeletal and Quantitative Imaging Research, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.,Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, San Francisco, California, USA
| | - C Benjamin Ma
- Musculoskeletal and Quantitative Imaging Research, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.,Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, California, USA
| | - Xiaojuan Li
- Musculoskeletal and Quantitative Imaging Research, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
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Carteron A, McPartlan K, Gioeli C, Reid E, Turturro M, Hahn B, Benson C, Zhang W. Temporary Nerve Block at Selected Digits Revealed Hand Motor Deficits in Grasping Tasks. Front Hum Neurosci 2016; 10:596. [PMID: 27932964 PMCID: PMC5122577 DOI: 10.3389/fnhum.2016.00596] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 11/09/2016] [Indexed: 01/04/2023] Open
Abstract
Peripheral sensory feedback plays a crucial role in ensuring correct motor execution throughout hand grasp control. Previous studies utilized local anesthesia to deprive somatosensory feedback in the digits or hand, observations included sensorimotor deficits at both corticospinal and peripheral levels. However, the questions of how the disturbed and intact sensory input integrate and interact with each other to assist the motor program execution, and whether the motor coordination based on motor output variability between affected and non-affected elements (e.g., digits) becomes interfered by the local sensory deficiency, have not been answered. The current study aims to investigate the effect of peripheral deafferentation through digital nerve blocks at selective digits on motor performance and motor coordination in grasp control. Our results suggested that the absence of somatosensory information induced motor deficits in hand grasp control, as evidenced by reduced maximal force production ability in both local and non-local digits, impairment of force and moment control during object lift and hold, and attenuated motor synergies in stabilizing task performance variables, namely the tangential force and moment of force. These findings implied that individual sensory input is shared across all the digits and the disturbed signal from local sensory channel(s) has a more comprehensive impact on the process of the motor output execution in the sensorimotor integration process. Additionally, a feedback control mechanism with a sensation-based component resides in the formation process for the motor covariation structure.
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Affiliation(s)
- Aude Carteron
- Department of Physical Therapy, College of Staten Island, City University of New York Staten Island, NY, USA
| | - Kerry McPartlan
- Department of Physical Therapy, College of Staten Island, City University of New York Staten Island, NY, USA
| | - Christina Gioeli
- Department of Physical Therapy, College of Staten Island, City University of New York Staten Island, NY, USA
| | - Emily Reid
- Department of Physical Therapy, College of Staten Island, City University of New York Staten Island, NY, USA
| | - Matt Turturro
- Department of Physical Therapy, College of Staten Island, City University of New York Staten Island, NY, USA
| | - Barry Hahn
- Emergency Medicine, Staten Island University Hospital Staten Island, NY, USA
| | - Cynthia Benson
- Emergency Medicine, Staten Island University Hospital Staten Island, NY, USA
| | - Wei Zhang
- Department of Physical Therapy, College of Staten Island, City University of New YorkStaten Island, NY, USA; Ph.D. Program in Biology, Graduate School and University Center, City University of New YorkNew York, NY, USA
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16
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Abstract
For a pair of random Gaussian integers chosen uniformly and independently from the set of Gaussian integers of norm x or less as x goes to infinity, we find asymptotics for the average norm of their greatest common divisor, with explicit error terms. We also present results for higher moments along with computational data which support the results for the second, third, fourth, and fifth moments. The analogous question for integers is studied by Diaconis and Erdös.
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Affiliation(s)
- Tai-Danae Bradley
- B.S. P rogram in M athematics , T he C ity C ollege of N ew Y ork , C onvent A ve . at 138 th S t ., NY 10031
| | - Yin Choi Cheng
- B.S. P rogram in M athematics , T he C ity C ollege of N ew Y ork , C onvent A ve . at 138 th S t ., NY 10031
| | - Yan Fei Luo
- B.S. P rogram in M athematics , T he C ity C ollege of N ew Y ork , C onvent A ve . at 138 th S t ., NY 10031
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17
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Ajami S, Mina A, Nabavizadeh SA. Stress distributions of a bracket type orthodontic miniscrew and the surrounding bone under moment loadings: Three-dimensional finite element analysis. J Orthod Sci 2016; 5:64-9. [PMID: 27127753 PMCID: PMC4830140 DOI: 10.4103/2278-0203.179416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Objectives: To evaluate the effect of moments and the combination of forces and moments on the mechanical properties of a bracket type miniscrew, resembling engagement of a rectangular wire by three-dimensional (3D) finite element study. Materials and Methods: By solid work software (Dassaunlt systems solid works, concord, Mass), a 3D miniscrew model of 6, 8, 10 mm lengths was designed and inserted in the osseous block, consisted of the cortical, and cancellous bones. The stress distributions, maximum stresses, and deflections of the miniscrew were evaluated for all parts using ANSYS (Work Bench, 2014). Results: As the magnitudes of the load increased from 100 to 200, 400 and 800 grf-mm, the peak of stresses in the 6 mm long miniscrew were increased from 7.7 to 61.5 Mpa. The maximum values of Von Mises in the cancellous bone were tremendously lower in comparison to the cortical bone by one hundredth. As the length of the miniscrew in contact with the bone was increased, the amounts and patterns of stress distribution in the cortical bone and the miniscrew did not change significantly. Conclusions: As the moment magnitude increased, the pick stresses increased linearly. The existence of cancellous bone was not significantly responsible for the stress distribution. The pattern of stress distribution did not change by the length of the miniscrew.
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Affiliation(s)
- Shabnam Ajami
- Orthodontic Research Center, Department of Orthodontic, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ahmad Mina
- Undergraduate Student, Student Research Committee, School of Dentistry, Shiraz University of Medical Science, Shiraz, Iran
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18
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Pohl MB, Kendall KD, Patel C, Wiley JP, Emery C, Ferber R. Experimentally reduced hip-abductor muscle strength and frontal-plane biomechanics during walking. J Athl Train 2015; 50:385-91. [PMID: 25875071 DOI: 10.4085/1062-6050-49.5.07] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Researchers have postulated that reduced hip-abductor muscle strength may have a role in the progression of knee osteoarthritis by increasing the external knee-adduction moment. However, the relationship between hip-abductor strength and frontal-plane biomechanics remains unclear. OBJECTIVE To experimentally reduce hip-abduction strength and observe the subsequent changes in frontal-plane biomechanics. DESIGN Descriptive laboratory study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Eight healthy, recreationally active men (age = 27 ± 6 years, height = 1.75 ± 0.11 m, mass = 76.1 ± 10.0 kg). INTERVENTION(S) All participants underwent a superior gluteal nerve block injection to reduce the force output of the hip-abductor muscle group. MAIN OUTCOME MEASURE(S) Maximal isometric hip-abduction strength and gait biomechanical data were collected before and after the injections. Gait biomechanical variables collected during walking consisted of knee- and hip-adduction moments and impulses and the peak angles of contralateral pelvic drop, hip adduction, and ipsilateral trunk lean. RESULTS Hip-abduction strength was reduced after the injection (P = .001) and remained lower than baseline values at the completion of the postinjection gait data collection (P = .02). No alterations in hip- or knee-adduction moments (hip: P = .11; knee: P = .52) or impulses (hip: P = .16; knee: P = .41) were found after the nerve block. Similarly, no changes in angular kinematics were observed for contralateral pelvic drop (P = .53), ipsilateral trunk lean (P = .78), or hip adduction (P = .48). CONCLUSIONS A short-term reduction in hip-abductor strength was not associated with alterations in the frontal-plane gait biomechanics of young, healthy men. Further research is needed to determine whether a similar relationship is true in older adults with knee osteoarthritis.
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Affiliation(s)
- Michael B Pohl
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington
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Katz NM. On a question of Rudnick: do we have square root cancellation for error terms in moment calculations? Philos Trans A Math Phys Eng Sci 2015; 239:rsta.2014.0312. [PMID: 25802417 DOI: 10.1098/rsta.2014.0312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We answer a question of Rudnick, largely in the negative, as to whether we have square root cancellation for error terms in moment calculations.
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Affiliation(s)
- Nicholas M Katz
- Department of Mathematics, Princeton University, Fine Hall, NJ 08544-1000, USA
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20
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Mittal N, Xia Z, Chen J, Stewart KT, Liu SSY. Three-dimensional quantification of pretorqued nickel-titanium wires in edgewise and prescription brackets. Angle Orthod 2013; 83:484-490. [PMID: 23095073 PMCID: PMC8763072 DOI: 10.2319/062812-532.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 09/01/2012] [Indexed: 07/31/2023] Open
Abstract
OBJECTIVE To quantify the three-dimensional moments and forces produced by pretorqued nickel-titanium (NiTi) rectangular archwires fully engaged in 0.018- and 0.022-inch slots of central incisor and molar edgewise and prescription brackets. MATERIALS AND METHODS Ten identical acrylic dental models with retroclined maxillary incisors were fabricated for bonding with various bracket-wire combinations. Edgewise, Roth, and MBT brackets with 0.018- and 0.022-inch slots were bonded in a simulated 2 × 4 clinical scenario. The left central incisor and molar were sectioned and attached to load cells. Correspondingly sized straight and pretorqued NiTi archwires were ligated to the brackets using 0.010-inch ligatures. Each load cell simultaneously measured three force (Fx, Fy, Fz) and three moment (Mx, My, Mz) components. The faciolingual, mesiodistal, and inciso-occluso/apical axes of the teeth corresponded to the x, y, and z axes of the load cells, respectively. Each wire was removed and retested seven times. Three-way analysis of variance (ANOVA) examined the effects of wire type, wire size, and bracket type on the measured orthodontic load systems. Interactions among the three effects were examined and pair-wise comparisons between significant combinations were performed. RESULTS The force and moment components on each tooth were quantified according to their local coordinate axes. The three-way ANOVA interaction terms were significant for all force and moment measurements (P < .05), except for Fy (P > .05). CONCLUSION The pretorqued wire generates a significantly larger incisor facial crown torquing moment in the MBT prescription compared to Roth, edgewise, and the straight NiTi wire.
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Affiliation(s)
- Nitika Mittal
- Resident, Department of Orthodontics and Oral Facial Genetics, Indiana University School of Dentistry, Indianapolis, IN
| | - Zeyang Xia
- Assistant Research Professor, Department of Mechanical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN
| | - Jie Chen
- Professor and Department Chair, Department of Mechanical Engineering, and Professor, Department of Oral Facial Development, Indiana University-Purdue University Indianapolis, Indianapolis, IN
| | - Kelton T. Stewart
- Assistant Professor, Department of Orthodontics and Oral Facial Genetics, Indiana University School of Dentistry, Indianapolis, IN
| | - Sean Shih-Yao Liu
- Assistant Professor, Department of Orthodontics and Oral Facial Genetics, Indiana University School of Dentistry, Indianapolis, IN
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Abstract
The inability to identify 3-D force and moment components for actuators and sensors is a major limiting factor in the study of 3-D force interactions with small-scale biological structures. While recent advances have been made in the measurement of stimulating forces using load cells and atomic-force microscopy in experimental preparations of biological structures such as mammalian temporal bones, these techniques have mostly been limited to one or two dimensions. In this paper, a method is described for stimulating biological structures using a small magnet (2 mg Sm(2)Co(17)) and a nearby current-conducting coil (46 gauge, 50 turns), that allows the 3-D Lorentz forces and moments acting on the magnet to be calculated. To make these calculations possible, the dimensions and placements of the magnet and coil are accurately determined (within 10 μm for in vitro preparations) using high-resolution micro-CT imaging. This noncontact force motor method has been used to study the mechanics of the malleus-incus complex in the mammalian middle ear in addition to basilar membrane mechanics and fluid flow inside the cochlea, and it can also be applied to the study of other biomechanical structures.
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Affiliation(s)
| | - Sunil Puria
- Department of Mechanical Engineering and the Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, CA 94305 USA
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22
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Schulz BW, Ashton-Miller JA, Alexander NB. Maximum step length: relationships to age and knee and hip extensor capacities. Clin Biomech (Bristol, Avon) 2007; 22:689-96. [PMID: 17434245 PMCID: PMC5321105 DOI: 10.1016/j.clinbiomech.2007.02.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Revised: 02/20/2007] [Accepted: 02/21/2007] [Indexed: 02/07/2023]
Abstract
BACKGROUND Maximum Step Length may be used to identify older adults at increased risk for falls. Since leg muscle weakness is a risk factor for falls, we tested the hypotheses that maximum knee and hip extension speed, strength, and power capacities would significantly correlate with Maximum Step Length and also that the "step out and back" Maximum Step Length [Medell, J.L., Alexander, N.B., 2000. A clinical measure of maximal and rapid stepping in older women. J. Gerontol. A Biol. Sci. Med. Sci. 55, M429-M433.] would also correlate with the Maximum Step Length of its two sub-tasks: stepping "out only" and stepping "back only". These sub-tasks will be referred to as versions of Maximum Step Length. METHODS Unimpaired younger (N=11, age=24[3]years) and older (N=10, age=73[5]years) women performed the above three versions of Maximum Step Length. Knee and hip extension speed, strength, and power capacities were determined on a separate day and regressed on Maximum Step Length and age group. Version and practice effects were quantified and subjective impressions of test difficulty recorded. Hypotheses were tested using linear regressions, analysis of variance, and Fisher's exact test. FINDINGS Maximum Step Length explained 6-22% additional variance in knee and hip extension speed, strength, and power capacities after controlling for age group. Within- and between-block and test-retest correlation values were high (>0.9) for all test versions. INTERPRETATION Shorter Maximum Step Lengths are associated with reduced knee and hip extension speed, strength, and power capacities after controlling for age. A single out-and-back step of maximal length is a feasible, rapid screening measure that may provide insight into underlying functional impairment, regardless of age.
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Affiliation(s)
- Brian W. Schulz
- Patient Safety Center, James A. Haley Veterans Hospital, Tampa, FL, USA,Department of Biomedical Engineering Biomechanics Research Laboratory,Department of Internal Medicine, Division of Geriatric Medicine, Mobility Research Center,Institute of Gerontology, University of Michigan, Ann Arbor, MI, USA
| | - James A. Ashton-Miller
- Department of Biomedical Engineering Biomechanics Research Laboratory,Institute of Gerontology, University of Michigan, Ann Arbor, MI, USA
| | - Neil B. Alexander
- Department of Internal Medicine, Division of Geriatric Medicine, Mobility Research Center,Institute of Gerontology, University of Michigan, Ann Arbor, MI, USA,VA Ann Arbor Health Care System Geriatrics Research Education and Clinical Center (GRECC), USA
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