Ryan Murphy - Academia.edu (original) (raw)

Papers by Ryan Murphy

Ieee Transactions on Medical Imaging, 2001

The reconstruction of tomographic images is often treated as a linear deblurring problem. When a ... more The reconstruction of tomographic images is often treated as a linear deblurring problem. When a high-density, man-made metal object is present somewhere in the image field, it is a deblurring problem in which the unknown function has a component that is known except for some location and orientation parameters. We first address general linear deblurring problems in which a known function having unknown parameters is present. We then show how the resulting iterative solution can be applied to tomographic imaging in the presence of man-made foreign objects, and we apply the result, in particular, to X-ray computed tomography imaging used in support of brachytherapy treatment of advanced cervical cancer.

Using a nonlinear model that accounts for the Poisson data acquired in transmission tomography, a... more Using a nonlinear model that accounts for the Poisson data acquired in transmission tomography, as well as effects such as noise, scatter, and spectral hardening, we developed an alternating minimization algorithm for image reconstruction. The algorithm is adapted to include a search for the pose of known objects in the reconstructed image, thus improving the image quality and the convergence rate.

Interleukin 7 (IL-7) and T cell receptor (TCR) signals have been proposed to be the primary drive... more Interleukin 7 (IL-7) and T cell receptor (TCR) signals have been proposed to be the primary drivers of homeostatic T cell proliferation. However, it is not known why CD4 + T cells undergo less efficient homeostatic proliferation than CD8 + T cells. Here we showed that systemic IL-7 concentrations rise during lymphopenia due to diminished IL-7 utilization, but that IL-7 signaling on IL-7Rα + dendritic cells (DCs) in lymphopenic settings paradoxically diminishes CD4 + T cell homeostatic proliferation. This effect is mediated, at least in part, by IL-7-mediated downregulation of MHC class II expression on IL-7Rα + DCs. These results implicate IL-7Rα + DCs as regulators of the peripheral CD4 + T cell niche, and indicate that IL-7 signals in DCs prevent uncontrolled CD4 + T cell expansion in vivo.

The economics literature generally finds a positive, but small, gain in income to native-born pop... more The economics literature generally finds a positive, but small, gain in income to native-born populations from immigrants and potentially large gains in world incomes. But immigrants can also impact a recipient nation’s institutions. A growing empirical literature supports the importance of strong private property rights, a rule of law, and an environment of economic freedom for promoting long run prosperity. Although the literature on the impact of economic freedom on various social and economic outcomes is quite large, comparatively little work has tried to explain economic freedom as a dependent variable. This paper empirically examines how immigration impacts a region’s policies and institutions. We find small but positive increases in institutional quality as a result of immigration.

Advanced Photon Counting Techniques IX, 2015

Advanced Wavefront Control: Methods, Devices, and Applications V, 2007

Phase Diversity (PD) is a wavefront-sensing technology that offers certain advantages in an Adapt... more Phase Diversity (PD) is a wavefront-sensing technology that offers certain advantages in an Adaptive-Optics (AO) system. Historically, PD has not been considered for use in AO applications because computations have been prohibitive. However, algorithmic and computational-hardware advances have recently allowed use of PD in AO applications. PD is an attractive candidate for AO applications for a variety of reasons. The optical hardware required is simple to implement and eliminates non-common path errors. In addition, PD has also been shown to work well with extended scenes that are encountered, for example, when imaging low-contrast solar granulation. PD can estimate high-order continuous aberrations as well as wavefront discontinuities characteristic of segmented-aperture or sparse-aperture telescope designs. Furthermore, the fundamental information content in a PD data set is shown to be greater than that of the correlation Shack-Hartmann wavefront sensor for the limiting case of unresolved objects. These advantages coupled with recent laboratory results (extended-scene closed-loop AO with PD sampling at 100 Hz) highlight the maturation of not only the PD concept and algorithm but the technology as an emerging and viable wavefront sensor for use in AO applications.

Plastic and Reconstructive Surgery, 2015

The aesthetic and functional outcomes surrounding Le Fortbased, face-jaw-teeth transplantation ha... more The aesthetic and functional outcomes surrounding Le Fortbased, face-jaw-teeth transplantation have been suboptimal, often leading to posttransplant class II/III skeletal profiles, palatal defects, and "hybrid malocclusion." Therefore, a novel technology-real-time cephalometry-was developed to provide the surgical team instantaneous, intraoperative knowledge of three-dimensional dentoskeletal parameters. Methods: Mock face-jaw-teeth transplantation operations were performed on plastic and cadaveric human donor/recipient pairs (n = 2). Preoperatively, cephalometric landmarks were identified on donor/recipient skeletons using segmented computed tomographic scans. The computer-assisted planning and execution workstation tracked the position of the donor face-jaw-teeth segment in real time during the placement/inset onto recipient, reporting pertinent hybrid cephalometric parameters from any movement of donor tissue. The intraoperative data measured through real-time cephalometry were compared to posttransplant measurements for accuracy assessment. In addition, posttransplant cephalometric relationships were compared to planned outcomes to determine face-jaw-teeth transplantation success. Results: Compared with postoperative data, the real-time cephalometry-calculated intraoperative measurement errors were 1.37 ± 1.11 mm and 0.45 ± 0.28 degrees for the plastic skull and 2.99 ± 2.24 mm and 2.63 ± 1.33 degrees for the human cadaver experiments. These results were comparable to the posttransplant relations to planned outcome (human cadaver experiment, 1.39 ± 1.81 mm and 2.18 ± 1.88 degrees; plastic skull experiment, 1.06 ± 0.63 mm and 0.53 ± 0.39 degrees). Conclusion: Based on this preliminary testing, real-time cephalometry may be a valuable adjunct for adjusting and measuring "hybrid occlusion" in face-jaw-teeth transplantation and other orthognathic surgical procedures. (Plast. Reconstr. Surg. 136: 350, 2015.)

Fluid-based directed assembly of functional nanoparticles is a promising approach to rapid fabric... more Fluid-based directed assembly of functional nanoparticles is a promising approach to rapid fabrication of future devices. Current approaches of precise placement of these nanoscale building blocks onto pre-defined positions formed by lithography are of current interest. These methods allow for designer surfaces containing feature sizes both chemical and topological on the nanometer length scale. However, little is known about the

Quantum Information and Computation XIII, 2015

ABSTRACT

2013 IEEE International Conference on Robotics and Automation, 2013

ABSTRACT Osteolysis is a debilitating condition that can occur behind the acetabular component of... more ABSTRACT Osteolysis is a debilitating condition that can occur behind the acetabular component of total hip replacements due to wear of the polyethylene liner. Conventional treatment techniques suggest replacing the component, while less-invasive approaches attempt to access and clean the lesion through the screw holes in the component. However, current rigid tools have been shown to access at most 50% of the lesion. Using a recently developed dexterous manipulator, we have adapted a group-theoretic convolution framework to define the manipulator's workspace and its ability to fully explore a lesion. We compared this with the experimental exploration of a printed model of the lesion. This convolution approach successfully contains the experimental results and shows over 98.8% volumetric coverage of a complex lesion. The results suggest this manipulator as a possible solution to accessing much of the area unreachable to the conventional less-invasive technique.

2012 IEEE International Conference on Robotics and Automation, 2012

This paper presents a method for estimating drive cable length in an underactuated, hyper-redunda... more This paper presents a method for estimating drive cable length in an underactuated, hyper-redundant, snake-like manipulator. The continuum manipulator was designed for the surgical removal of osteolysis behind total hip arthroplasties. Two independently actuated cables in a pull-pull configuration control the compliant manipulator in a single plane. Using a previously developed kinematic model, we present a method for estimating drive cable displacement for a given manipulator configuration. This calibrated function is then inverted to explore the ability to achieve local manipulator configurations from prescribed drive cable displacements without the use of continuous visual feedback. Results demonstrate an effectiveness in predicting drive cable lengths from manipulator configurations. Preliminary results also show an ability to achieve manipulator configurations from prescribed cable lengths with reasonable accuracy without continuous visual feedback.

Frontiers in Bioengineering and Biotechnology, 2013

Objective:This study addresses the effects of cartilage thickness distribution and compressive pr... more Objective:This study addresses the effects of cartilage thickness distribution and compressive properties in the context of optimal alignment planning for periacetabular osteotomy (PAO).

The Journal of Bone & Joint Surgery, 2015

Certain fracture configurations, especially spiral fractures, are often thought to be indicative ... more Certain fracture configurations, especially spiral fractures, are often thought to be indicative of nonaccidental trauma in children. The purpose of this study was to determine whether femoral fracture morphology, as determined by an objective measurement (fracture ratio), was indicative of nonaccidental trauma in young children. Consecutive patients who were three years of age or younger and had a closed, isolated femoral shaft fracture treated at an urban pediatric level-I trauma center between 2005 and 2013 were identified. Anteroposterior and lateral fracture ratios (fracture length/bone diameter) were calculated for each patient by a fellowship-trained pediatric orthopaedic surgeon who was blinded to the patient's clinical history. The presence or absence of a Child Protective Services referral as well as institutional Child Assessment Program evaluations were reviewed. Nonaccidental trauma was deemed to be present, absent, or indeterminate by Child Protective Services or an on-site Child Assessment Program team. To further evaluate and quantify the likelihood of nonaccidental trauma, the criteria of the Modified Maltreatment Classification System were used. Of 122 patients identified, ninety-five met the inclusion criteria for this study. Of these ninety-five, fifty-one (54%) had either a Child Protective Services or a Child Assessment Program consultation because of suspected nonaccidental trauma. Thirteen (25%) were found to have nonaccidental trauma as determined by Child Protective Services or the Child Assessment Program team and seven (14%) had indeterminate Child Protective Services or Child Assessment Program investigations. All thirteen patients with nonaccidental trauma, as well as the seven patients with an indeterminate Child Protective Services or Child Assessment Program investigation, had positive Modified Maltreatment Classification System scores for physical abuse. Patients who had nonaccidental trauma had significantly decreased mean anteroposterior fracture ratios compared with those who had confirmed accidental trauma (p < 0.0001). The fracture ratio can be helpful to determine fracture morphology and can be used as part of the assessment of a child with suspected nonaccidental trauma. While not diagnostic, the presence of a transverse diaphyseal femoral fracture in a young child should raise the index of suspicion for nonaccidental trauma. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Three-Dimensional Image Capture and Applications 2008, 2008

For over thirty years researchers have been trying to solve the shape from shading problem of det... more For over thirty years researchers have been trying to solve the shape from shading problem of determining 3D shape from a single image with a single light source. The basic problem of determining shape from shading is made more difficult due to challenges of light orientation, camera type, ambiguity, multiple materials, and specular highlights. This paper shows how some of these challenges can be overcome through the use of other techniques such as image segmentation and stereopsis. We present a new hybrid method of shape from shading that can be used to autonomously capture 3D information from two 2D images of single objects with multiple peaks and multiple materials with specular components.

Volume 4: 18th Design for Manufacturing and the Life Cycle Conference; 2013 ASME/IEEE International Conference on Mechatronic and Embedded Systems and Applications, 2013

We report the results of planning and experimental validation of femoroplasty-augmentation of mec... more We report the results of planning and experimental validation of femoroplasty-augmentation of mechanical properties of the bone using polymethylmethacrylate (PMMA) bone cement injection-on osteoporotic femurs. For six pairs of osteoporotic femurs, finite element (FE) models were created using computed tomography (CT) scan data and an evolutionary method was used to optimize the cement pattern in one of the models from each pair. Using a particle method and the CT data, cement diffusion was modeled for several hypothetical augmentations and the one most closely matching the optimized pattern was chosen as the best plan. We used intra-operative navigation and a custom-designed injection device to deliver the cement into the bones precisely according to the plan. All femurs were then tested mechanically in a configuration simulating a fall to the side. Augmentation with this technique resulted in an increase in the yield load (28%) and yield energy (142%) compared to the control specimens, while only 9.8ml of cement was injected on average. Results support our hypothesis that significant im-provements in the mechanical properties of osteoporotic femurs can be achieved by using minimal, and hence safe, amounts of PMMA bone cement.

Journal of biomechanics, Jan 2, 2015

The risk of osteoporotic hip fractures may be reduced by augmenting susceptible femora with acryl... more The risk of osteoporotic hip fractures may be reduced by augmenting susceptible femora with acrylic polymethylmethacrylate (PMMA) bone cement. Grossly filling the proximal femur with PMMA has shown promise, but the augmented bones can suffer from thermal necrosis or cement leakage, among other side effects. We hypothesized that, using subject-specific planning and computer-assisted augmentation, we can minimize cement volume while increasing bone strength and reducing the risk of fracture. We mechanically tested eight pairs of osteoporotic femora, after augmenting one from each pair following patient-specific planning reported earlier, which optimized cement distribution and strength increase. An average of 9.5(±1.7) ml of cement was injected in the augmented set. Augmentation significantly (P<0.05) increased the yield load by 33%, maximum load by 30%, yield energy by 118%, and maximum energy by 94% relative to the non-augmented controls. Also predicted yield loads correlated wel...

The Journal of Craniofacial Surgery, 2014

Swine are often regarded as having analogous facial skeletons to humans and therefore serve as an... more Swine are often regarded as having analogous facial skeletons to humans and therefore serve as an ideal animal model for translational investigation. However, there is a dearth of literature describing the pertinent ancillary procedures required for craniomaxillofacial research. With this in mind, our objective was to evaluate all necessary procedures required for perioperative management and animal safety related to experimental craniomaxillofacial surgical procedures such as orthotopic, maxillofacial transplantation. Miniature swine (n = 9) were used to investigate perioperative airway management, methods for providing nutrition, and long-dwelling intravenous access. Flap perfusion using near-infrared laser angiography and facial nerve assessment with electromyoneurography were explored. Bivona tracheostomy was deemed appropriate versus Shiley because soft, wire-reinforced tubing reduced the incidence of tracheal necrosis. Percutaneous endoscopic gastrostomy tube, as opposed to esophagostomy, provided a reliable route for postoperative feeding. Femoral venous access with dorsal tunneling proved to be an ideal option being far from pertinent neck vessels. Laser angiography was beneficial for real-time evaluation of graft perfusion. Facial electromyoneurography techniques for tracing capture were found most optimal using percutaneous leads near the oral commissure.Experience shows that ancillary procedures are critical, and malpositioning of devices may lead to irreversible sequelae with premature animal death. Face-jaw-teeth transplantation in swine is a complicated procedure that demands special attention to airway, feeding, and intravascular access. It is critical that each ancillary procedure be performed by a dedicated team familiar with relevant anatomy and protocol. Emphasis should be placed on secure skin-level fixation for all tube/lines to minimize risk for dislodgement. A reliable veterinarian team is invaluable and critical for long-term success.

Ieee Transactions on Medical Imaging, 2001

The reconstruction of tomographic images is often treated as a linear deblurring problem. When a ... more The reconstruction of tomographic images is often treated as a linear deblurring problem. When a high-density, man-made metal object is present somewhere in the image field, it is a deblurring problem in which the unknown function has a component that is known except for some location and orientation parameters. We first address general linear deblurring problems in which a known function having unknown parameters is present. We then show how the resulting iterative solution can be applied to tomographic imaging in the presence of man-made foreign objects, and we apply the result, in particular, to X-ray computed tomography imaging used in support of brachytherapy treatment of advanced cervical cancer.

Using a nonlinear model that accounts for the Poisson data acquired in transmission tomography, a... more Using a nonlinear model that accounts for the Poisson data acquired in transmission tomography, as well as effects such as noise, scatter, and spectral hardening, we developed an alternating minimization algorithm for image reconstruction. The algorithm is adapted to include a search for the pose of known objects in the reconstructed image, thus improving the image quality and the convergence rate.

Interleukin 7 (IL-7) and T cell receptor (TCR) signals have been proposed to be the primary drive... more Interleukin 7 (IL-7) and T cell receptor (TCR) signals have been proposed to be the primary drivers of homeostatic T cell proliferation. However, it is not known why CD4 + T cells undergo less efficient homeostatic proliferation than CD8 + T cells. Here we showed that systemic IL-7 concentrations rise during lymphopenia due to diminished IL-7 utilization, but that IL-7 signaling on IL-7Rα + dendritic cells (DCs) in lymphopenic settings paradoxically diminishes CD4 + T cell homeostatic proliferation. This effect is mediated, at least in part, by IL-7-mediated downregulation of MHC class II expression on IL-7Rα + DCs. These results implicate IL-7Rα + DCs as regulators of the peripheral CD4 + T cell niche, and indicate that IL-7 signals in DCs prevent uncontrolled CD4 + T cell expansion in vivo.

The economics literature generally finds a positive, but small, gain in income to native-born pop... more The economics literature generally finds a positive, but small, gain in income to native-born populations from immigrants and potentially large gains in world incomes. But immigrants can also impact a recipient nation’s institutions. A growing empirical literature supports the importance of strong private property rights, a rule of law, and an environment of economic freedom for promoting long run prosperity. Although the literature on the impact of economic freedom on various social and economic outcomes is quite large, comparatively little work has tried to explain economic freedom as a dependent variable. This paper empirically examines how immigration impacts a region’s policies and institutions. We find small but positive increases in institutional quality as a result of immigration.

Advanced Photon Counting Techniques IX, 2015

Advanced Wavefront Control: Methods, Devices, and Applications V, 2007

Phase Diversity (PD) is a wavefront-sensing technology that offers certain advantages in an Adapt... more Phase Diversity (PD) is a wavefront-sensing technology that offers certain advantages in an Adaptive-Optics (AO) system. Historically, PD has not been considered for use in AO applications because computations have been prohibitive. However, algorithmic and computational-hardware advances have recently allowed use of PD in AO applications. PD is an attractive candidate for AO applications for a variety of reasons. The optical hardware required is simple to implement and eliminates non-common path errors. In addition, PD has also been shown to work well with extended scenes that are encountered, for example, when imaging low-contrast solar granulation. PD can estimate high-order continuous aberrations as well as wavefront discontinuities characteristic of segmented-aperture or sparse-aperture telescope designs. Furthermore, the fundamental information content in a PD data set is shown to be greater than that of the correlation Shack-Hartmann wavefront sensor for the limiting case of unresolved objects. These advantages coupled with recent laboratory results (extended-scene closed-loop AO with PD sampling at 100 Hz) highlight the maturation of not only the PD concept and algorithm but the technology as an emerging and viable wavefront sensor for use in AO applications.

Plastic and Reconstructive Surgery, 2015

The aesthetic and functional outcomes surrounding Le Fortbased, face-jaw-teeth transplantation ha... more The aesthetic and functional outcomes surrounding Le Fortbased, face-jaw-teeth transplantation have been suboptimal, often leading to posttransplant class II/III skeletal profiles, palatal defects, and "hybrid malocclusion." Therefore, a novel technology-real-time cephalometry-was developed to provide the surgical team instantaneous, intraoperative knowledge of three-dimensional dentoskeletal parameters. Methods: Mock face-jaw-teeth transplantation operations were performed on plastic and cadaveric human donor/recipient pairs (n = 2). Preoperatively, cephalometric landmarks were identified on donor/recipient skeletons using segmented computed tomographic scans. The computer-assisted planning and execution workstation tracked the position of the donor face-jaw-teeth segment in real time during the placement/inset onto recipient, reporting pertinent hybrid cephalometric parameters from any movement of donor tissue. The intraoperative data measured through real-time cephalometry were compared to posttransplant measurements for accuracy assessment. In addition, posttransplant cephalometric relationships were compared to planned outcomes to determine face-jaw-teeth transplantation success. Results: Compared with postoperative data, the real-time cephalometry-calculated intraoperative measurement errors were 1.37 ± 1.11 mm and 0.45 ± 0.28 degrees for the plastic skull and 2.99 ± 2.24 mm and 2.63 ± 1.33 degrees for the human cadaver experiments. These results were comparable to the posttransplant relations to planned outcome (human cadaver experiment, 1.39 ± 1.81 mm and 2.18 ± 1.88 degrees; plastic skull experiment, 1.06 ± 0.63 mm and 0.53 ± 0.39 degrees). Conclusion: Based on this preliminary testing, real-time cephalometry may be a valuable adjunct for adjusting and measuring "hybrid occlusion" in face-jaw-teeth transplantation and other orthognathic surgical procedures. (Plast. Reconstr. Surg. 136: 350, 2015.)

Fluid-based directed assembly of functional nanoparticles is a promising approach to rapid fabric... more Fluid-based directed assembly of functional nanoparticles is a promising approach to rapid fabrication of future devices. Current approaches of precise placement of these nanoscale building blocks onto pre-defined positions formed by lithography are of current interest. These methods allow for designer surfaces containing feature sizes both chemical and topological on the nanometer length scale. However, little is known about the

Quantum Information and Computation XIII, 2015

ABSTRACT

2013 IEEE International Conference on Robotics and Automation, 2013

ABSTRACT Osteolysis is a debilitating condition that can occur behind the acetabular component of... more ABSTRACT Osteolysis is a debilitating condition that can occur behind the acetabular component of total hip replacements due to wear of the polyethylene liner. Conventional treatment techniques suggest replacing the component, while less-invasive approaches attempt to access and clean the lesion through the screw holes in the component. However, current rigid tools have been shown to access at most 50% of the lesion. Using a recently developed dexterous manipulator, we have adapted a group-theoretic convolution framework to define the manipulator&#39;s workspace and its ability to fully explore a lesion. We compared this with the experimental exploration of a printed model of the lesion. This convolution approach successfully contains the experimental results and shows over 98.8% volumetric coverage of a complex lesion. The results suggest this manipulator as a possible solution to accessing much of the area unreachable to the conventional less-invasive technique.

2012 IEEE International Conference on Robotics and Automation, 2012

This paper presents a method for estimating drive cable length in an underactuated, hyper-redunda... more This paper presents a method for estimating drive cable length in an underactuated, hyper-redundant, snake-like manipulator. The continuum manipulator was designed for the surgical removal of osteolysis behind total hip arthroplasties. Two independently actuated cables in a pull-pull configuration control the compliant manipulator in a single plane. Using a previously developed kinematic model, we present a method for estimating drive cable displacement for a given manipulator configuration. This calibrated function is then inverted to explore the ability to achieve local manipulator configurations from prescribed drive cable displacements without the use of continuous visual feedback. Results demonstrate an effectiveness in predicting drive cable lengths from manipulator configurations. Preliminary results also show an ability to achieve manipulator configurations from prescribed cable lengths with reasonable accuracy without continuous visual feedback.

Frontiers in Bioengineering and Biotechnology, 2013

Objective:This study addresses the effects of cartilage thickness distribution and compressive pr... more Objective:This study addresses the effects of cartilage thickness distribution and compressive properties in the context of optimal alignment planning for periacetabular osteotomy (PAO).

The Journal of Bone & Joint Surgery, 2015

Certain fracture configurations, especially spiral fractures, are often thought to be indicative ... more Certain fracture configurations, especially spiral fractures, are often thought to be indicative of nonaccidental trauma in children. The purpose of this study was to determine whether femoral fracture morphology, as determined by an objective measurement (fracture ratio), was indicative of nonaccidental trauma in young children. Consecutive patients who were three years of age or younger and had a closed, isolated femoral shaft fracture treated at an urban pediatric level-I trauma center between 2005 and 2013 were identified. Anteroposterior and lateral fracture ratios (fracture length/bone diameter) were calculated for each patient by a fellowship-trained pediatric orthopaedic surgeon who was blinded to the patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s clinical history. The presence or absence of a Child Protective Services referral as well as institutional Child Assessment Program evaluations were reviewed. Nonaccidental trauma was deemed to be present, absent, or indeterminate by Child Protective Services or an on-site Child Assessment Program team. To further evaluate and quantify the likelihood of nonaccidental trauma, the criteria of the Modified Maltreatment Classification System were used. Of 122 patients identified, ninety-five met the inclusion criteria for this study. Of these ninety-five, fifty-one (54%) had either a Child Protective Services or a Child Assessment Program consultation because of suspected nonaccidental trauma. Thirteen (25%) were found to have nonaccidental trauma as determined by Child Protective Services or the Child Assessment Program team and seven (14%) had indeterminate Child Protective Services or Child Assessment Program investigations. All thirteen patients with nonaccidental trauma, as well as the seven patients with an indeterminate Child Protective Services or Child Assessment Program investigation, had positive Modified Maltreatment Classification System scores for physical abuse. Patients who had nonaccidental trauma had significantly decreased mean anteroposterior fracture ratios compared with those who had confirmed accidental trauma (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). The fracture ratio can be helpful to determine fracture morphology and can be used as part of the assessment of a child with suspected nonaccidental trauma. While not diagnostic, the presence of a transverse diaphyseal femoral fracture in a young child should raise the index of suspicion for nonaccidental trauma. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Three-Dimensional Image Capture and Applications 2008, 2008

For over thirty years researchers have been trying to solve the shape from shading problem of det... more For over thirty years researchers have been trying to solve the shape from shading problem of determining 3D shape from a single image with a single light source. The basic problem of determining shape from shading is made more difficult due to challenges of light orientation, camera type, ambiguity, multiple materials, and specular highlights. This paper shows how some of these challenges can be overcome through the use of other techniques such as image segmentation and stereopsis. We present a new hybrid method of shape from shading that can be used to autonomously capture 3D information from two 2D images of single objects with multiple peaks and multiple materials with specular components.

Volume 4: 18th Design for Manufacturing and the Life Cycle Conference; 2013 ASME/IEEE International Conference on Mechatronic and Embedded Systems and Applications, 2013

We report the results of planning and experimental validation of femoroplasty-augmentation of mec... more We report the results of planning and experimental validation of femoroplasty-augmentation of mechanical properties of the bone using polymethylmethacrylate (PMMA) bone cement injection-on osteoporotic femurs. For six pairs of osteoporotic femurs, finite element (FE) models were created using computed tomography (CT) scan data and an evolutionary method was used to optimize the cement pattern in one of the models from each pair. Using a particle method and the CT data, cement diffusion was modeled for several hypothetical augmentations and the one most closely matching the optimized pattern was chosen as the best plan. We used intra-operative navigation and a custom-designed injection device to deliver the cement into the bones precisely according to the plan. All femurs were then tested mechanically in a configuration simulating a fall to the side. Augmentation with this technique resulted in an increase in the yield load (28%) and yield energy (142%) compared to the control specimens, while only 9.8ml of cement was injected on average. Results support our hypothesis that significant im-provements in the mechanical properties of osteoporotic femurs can be achieved by using minimal, and hence safe, amounts of PMMA bone cement.

Journal of biomechanics, Jan 2, 2015

The risk of osteoporotic hip fractures may be reduced by augmenting susceptible femora with acryl... more The risk of osteoporotic hip fractures may be reduced by augmenting susceptible femora with acrylic polymethylmethacrylate (PMMA) bone cement. Grossly filling the proximal femur with PMMA has shown promise, but the augmented bones can suffer from thermal necrosis or cement leakage, among other side effects. We hypothesized that, using subject-specific planning and computer-assisted augmentation, we can minimize cement volume while increasing bone strength and reducing the risk of fracture. We mechanically tested eight pairs of osteoporotic femora, after augmenting one from each pair following patient-specific planning reported earlier, which optimized cement distribution and strength increase. An average of 9.5(±1.7) ml of cement was injected in the augmented set. Augmentation significantly (P<0.05) increased the yield load by 33%, maximum load by 30%, yield energy by 118%, and maximum energy by 94% relative to the non-augmented controls. Also predicted yield loads correlated wel...

The Journal of Craniofacial Surgery, 2014

Swine are often regarded as having analogous facial skeletons to humans and therefore serve as an... more Swine are often regarded as having analogous facial skeletons to humans and therefore serve as an ideal animal model for translational investigation. However, there is a dearth of literature describing the pertinent ancillary procedures required for craniomaxillofacial research. With this in mind, our objective was to evaluate all necessary procedures required for perioperative management and animal safety related to experimental craniomaxillofacial surgical procedures such as orthotopic, maxillofacial transplantation. Miniature swine (n = 9) were used to investigate perioperative airway management, methods for providing nutrition, and long-dwelling intravenous access. Flap perfusion using near-infrared laser angiography and facial nerve assessment with electromyoneurography were explored. Bivona tracheostomy was deemed appropriate versus Shiley because soft, wire-reinforced tubing reduced the incidence of tracheal necrosis. Percutaneous endoscopic gastrostomy tube, as opposed to esophagostomy, provided a reliable route for postoperative feeding. Femoral venous access with dorsal tunneling proved to be an ideal option being far from pertinent neck vessels. Laser angiography was beneficial for real-time evaluation of graft perfusion. Facial electromyoneurography techniques for tracing capture were found most optimal using percutaneous leads near the oral commissure.Experience shows that ancillary procedures are critical, and malpositioning of devices may lead to irreversible sequelae with premature animal death. Face-jaw-teeth transplantation in swine is a complicated procedure that demands special attention to airway, feeding, and intravascular access. It is critical that each ancillary procedure be performed by a dedicated team familiar with relevant anatomy and protocol. Emphasis should be placed on secure skin-level fixation for all tube/lines to minimize risk for dislodgement. A reliable veterinarian team is invaluable and critical for long-term success.