Serendipitous Geodesy from Bennu's Short-Lived Moonlets

The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx; or OREx) spacecraft arrived at its target, near-Earth asteroid (101955) Bennu, on December 3, 2018. The OSIRIS-REx spacecraft has since collected a wealth of scientific information in order to select a suitable site for sampling. Shortly after insertion into orbit on December 31, 2018, particles were identified in starfield images taken by the navigation camera (NavCam 1). Several groups within the OSlRlS-REx team analyzed the particle data in an effort to better understand this newfound activity of Bennu and to investigate the potential sensitivity of the particles to Bennu's geophysical parameters. A number of particles were identified through automatic and manual methods in multiple images, which could be turned into short sequences of optical tracking observations. Here, we discuss the precision orbit determination (OD) effort focused on these particles at NASA GSFC, which involved members of the Independent Navigation Team (INT) in particular. The particle data are combined with other OSIRIS-REx tracking data (radiometric from OSN and optical landmark data) using the NASA GSFC GEODYN orbit determination and geodetic parameter estimation software. We present the results of our study, particularly those pertaining to the gravity field of Bennu. We describe the force modeling improvements made to GEODYN specifically for this work, e.g., with a raytracing-based modeling of solar radiation pressure. The short-lived, low-flying moonlets enable us to determine a gravity field model up to a relatively high degree and order: at least degree 6 without constraints, and up to degree 10 when applying Kaula-like regularization. We can backward- and forward-integrate the trajectory of these particles to the ejection and landing sites on Bennu. We assess the recovered field by its impact on the OSIRIS-REx trajectory reconstruction and prediction quality in the various mission phases (e.g., Orbital A, Detailed Survey, and Orbital B)

Early Navigation Performance of the OSIRIS-REx Approach to Bennu

The New Frontiers-class OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) mission is the first American endeavor to return a sample from an asteroid. In preparation for retrieving the sample, OSIRIS-REx is conducting a campaign of challenging proximity-operations maneuvers and scientific observations, bringing the spacecraft closer and closer to the surface of near-Earth asteroid (101955) Bennu. Ultimately, the spacecraft will enter a 900-meter-radius orbit about Bennu and conduct a series of reconnaissance flybys of candidate sample sites before being guided into contact with the surface for the Touch and Go sample collection event. Between August and December 2018, the OSIRIS-REx team acquired the first optical observations of Bennu and used them for navigation. We conducted a series of maneuvers with the main engine, Trajectory Correction Maneuver, and Attitude Control System thruster sets to slow the OSIRIS-REx approach to Bennu and achieve rendezvous on December 3, 2018. This paper describes the trajectory design, navigation conops, and key navigation results from the Approach phase of the OSIRIS-REx mission

Preserving and Using Germplasm and Dissociated Embryonic Cells for Conserving Caribbean and Pacific Coral

Coral reefs are experiencing unprecedented degradation due to human activities, and protecting specific reef habitats may not stop this decline, because the most serious threats are global (i.e., climate change), not local. However, ex situ preservation practices can provide safeguards for coral reef conservation. Specifically, modern advances in cryobiology and genome banking could secure existing species and genetic diversity until genotypes can be introduced into rehabilitated habitats. We assessed the feasibility of recovering viable sperm and embryonic cells post-thaw from two coral species, Acropora palmata and Fungia scutaria that have diffferent evolutionary histories, ecological niches and reproductive strategies. In vitro fertilization (IVF) of conspecific eggs using fresh (control) spermatozoa revealed high levels of fertilization (>90% in A. palmata; >84% in F. scutaria; P>0.05) that were unaffected by tested sperm concentrations. A solution of 10% dimethyl sulfoxide (DMSO) at cooling rates of 20 to 30°C/min most successfully cryopreserved both A. palmata and F. scutaria spermatozoa and allowed producing developing larvae in vitro. IVF success under these conditions was 65% in A. palmata and 53% in F. scutaria on particular nights; however, on subsequent nights, the same process resulted in little or no IVF success. Thus, the window for optimal freezing of high quality spermatozoa was short (∼5 h for one night each spawning cycle). Additionally, cryopreserved F. scutaria embryonic cells had∼50% post-thaw viability as measured by intact membranes. Thus, despite some differences between species, coral spermatozoa and embryonic cells are viable after low temperature (−196°C) storage, preservation and thawing. Based on these results, we have begun systematically banking coral spermatozoa and embryonic cells on a large-scale as a support approach for preserving existing bio- and genetic diversity found in reef systems

Cervical Arthroplasty

Technological advances have allowed spine surgery to follow the trend toward minimally invasive surgery in general. Specifically, we have seen a corresponding rise in the popularity of cervical arthroplasty. For the treatment of cervical disc disease, arthroplasty is a less invasive option than the gold standard of cervical discectomy and arthrodesis, which by nature is more disruptive to surrounding tissues. Arthroplasty preserves the facets, maintains motion, and reduces the rate of adjacent segment breakdown. These factors counteract the negative impacts of fusion while maintaining the benefits. Arthroplasty implants themselves have become more streamlined to implant as well with less native bone destruction, and biomechanics more compatible with the native disc. While initial implants were ball and socket devices with complex fixation and plane-specific movements, later devices incorporated such motions as translation and compression. Viscoelastic components and materials more closely resembling native tissues afford a more biocompatible implant profile. Until cell-based therapies can successfully reproduce native tissue, we will rely on artificial components that closely resemble and assimilate them

Conforming artificial finger mechanism

A prosthetic finger includes a crossed four (4) bar linkage system having a base formed by a base bar, two cross bars, and an interface bar that engages an object to be held. The base bar is fixed to an artificial finger of an amputee. A first cross bar has a first end pivotally mounted to a first end of the base bar and a second cross bar has a first end pivotally mounted to a second end of the base bar. The first cross bar has a second end pivotally mounted to a first end of the interface bar and the second cross bar has a second end pivotally mounted to a second end of the interface bar. The first and second cross bars are slideably interconnected to one another at a cross point which changes its location as the prosthesis grasps objects of differing sizes and shapes

CONTEMPLATING HEALTH ECONOMICS, CODING AND REIMBURSEMENT IN ORTHOTICS, PROSTHETICS AND PEDORTHICS

Reimbursement to U.S. healthcare service providers is largely transitioning from fee for service to fee for value for those clinicians who code using current procedural terminology and through their coding, describe their professional services. The Orthotic, Prosthetic and Pedorthic profession (O&P), currently codes using a system that describes the devices they evaluate for, fabricate, fit and maintain and their professional services are incorporated into their codes. These O&P codes, in contrast to those for other healthcare disciplines, are predominantly product based rather than service based, focusing on product features and function more than clinical service. This editorial manuscript provides a brief overview of the system the US O&P profession uses currently, particularly in the context of other healthcare professions transitioning to value based coding and reimbursement and culminates in a call to action for the profession to academically consider the strengths and weaknesses of the current system relative to alternative systems. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/36125/28316 How To Cite: Highsmith MJ, Fantini CM, Smith DG. Contemplating health economics, coding and reimbursement in orthotics, prosthetics and pedorthics. Canadian Prosthetics & Orthotics Journal. 2021; Volume 4, Issue 2, No.5. https://doi.org/10.33137/cpoj.v4i2.36125 Corresponding Author: M. Jason Highsmith, PhD, DPT, CP, FAAOPSchool of Physical Therapy & Rehabilitation Sciences, Morsani College of Medicine, University of South Florida. Florida, USA.E-Mail: [email protected] ID: https://orcid.org/0000-0001-8361-734

Case Report: Decreased Heart Rate in a Geriatric Client Following Physical Therapy Intervention and Accommodation With the C-Leg

In this case report, a deconditioned, 82-year-old man underwent transfemoral amputation secondary to chronic infection after knee resurfacing. He was initially fit with a nonmicroprocessor knee as part of the preparatory prosthesis. Nine months after amputation, he was fit with a C-Leg as a component of the definitive prosthesis. As part of the first year of rehabilitation, the patient underwent four separate physical therapy (PT) programs that included strengthening, conditioning, and patient education interventions. Following accommodation on each of the two prostheses, the patient performed a distance-based, 75 m fastest possible walking speed test while wearing a heart rate (HR) monitor. HR, target HR, gait velocity, and physiologic cost index were measured or calculated to determine the physiologic outcomes of rehabilitation. There was a marked decrease in both resting and working HR after the fourth PT program and accommodation to the C-Leg. Target HR was also more appropriate after rehabilitation, which confirmed the decreased HR response. Because of the magnitude of HR reductions while resting and working, it is possible that the patient gave a submaximal effort in addition to experiencing a training effect. The physiologic cost index seemed to diminish the difference observed in HR because of the structure of the equation and was not found to be complementary to the HR data. As a result of PT intervention, the C-Leg knee prosthesis, and personal goals, the patient retained the ability to care for his dependent wife in the home

Conforming artificial finger mechanism

A prosthetic finger includes a crossed four (4) bar linkage system having a base formed by a base bar, two cross bars, and an interface bar that engages an object to be held. The base bar is fixed to an artificial finger of an amputee. A first cross bar has a first end pivotally mounted to a first end of the base bar and a second cross bar has a first end pivotally mounted to a second end of the base bar. The first cross bar has a second end pivotally mounted to a first end of the interface bar and the second cross bar has a second end pivotally mounted to a second end of the interface bar. The first and second cross bars are slideably interconnected to one another at a cross point which changes its location as the prosthesis grasps objects of differing sizes and shapes

3D Printed Tooling for Thermoforming of Medical Devices

Purpose: The purpose of this paper is to evaluate the performance of 3D printed materials for use as rapid tooling (RT) molds in low volume thermoforming processes such as in manufacturing custom prosthetics and orthotics. Design/methodology/approach: 3D printed specimens of different materials were produced using the Z-Corp process. The parts were post processed using both standard and alternative methods. Material properties relevant to the 3D printed parts such as pneumatic permeability, flexural strength and wear rate were measured and compared to standard plaster compositions commonly used. Findings: Three-dimensional printing (3DP) can replicate the performance of the plaster materials traditionally used in prosthetic/orthotic applications by using modified post process techniques. The resulting 3D printed molds can still be modified and adjusted using traditional methods. The results show that 3D printed molds are feasible for thermoforming prosthetic and orthotic devices such as prosthetic sockets while providing new flexibility. Originality/value: The proposed method for RT of a mold for prosthetic/orthotic manufacturing provides great flexibility in the manufacturing and fitting process while maintaining proven materials in the final device provided to patients. This flexibility increases the value of digital medical records and efforts to develop model-based approaches to prosthetic/orthotic device design by providing a readily available process for recreating molds. Depending on the needs of the practitioners and patients, 3DP can be incorporated at a variety of points in the manufacturing process

Comparison of the Metabolic Demands of Dance Performance Using Three Mobility Devices for a Dancer with Spinal Cord Injury and an Able-Bodied Dancer

Mobility devices for dancers with physical mobility impairments have previously been limited to traditional manual or power wheelchairs. The hands-free torso-controlled mobility chair is a unique powered mobility device which allows greater freedom and expression of movement of the trunk and upper extremities. This study compared differences in energy expenditure during a standardized dance activity using three mobility devices: the hands-free torso-controlled mobility chair, a manual sports wheelchair with hand-arm control, and an electric power chair with hand-joystick control. An experienced dancer with C7 incomplete spinal cord injury (SCI) and an experienced able-bodied dancer were recruited for testing. Three measurement trials were obtained for each chair per subject. Oxygen uptake (VO2) and heart rate (HR) were measured continuously during the dance activity. Immediately following the dance activity, subjects rated perceived exertion. Significant differences (p\u3c0.05) and similar linear patterns in VO2 and HR responses were observed between chairs for both dancers. When the hands-free mobility chair was used, the dance activity required a moderate level of energy expenditure compared to the manual sports chair or electric power chair for both dancers. Higher ratings of perceived exertion were observed in the manual chair compared to the other chairs for the dancer with SCI, but were similar between chairs for the able-bodied dancer. These results suggest that for a dancer with high-level SCI, the hands-free torso-controlled mobility chair may offer improved freedom and expressive movement possibilities and is an energy-efficient mobility device