@article{miller_jernigan_abraham_buckner_2024, title={Comparing Deposition Characteristics of Various Embolic Particles Using an In Vitro Prostate Microvasculature Model}, volume={35}, ISSN={["1535-7732"]}, DOI={10.1016/j.jvir.2024.06.028}, abstractNote={To compare spatial distributions of radiopaque glass (RG) microspheres, tris-acryl gelatin (TAG) microspheres, and polyvinyl alcohol (PVA) nonspherical foam particles within a planar in vitro microvascular model of the hyperplastic hemiprostate.}, number={10}, journal={JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY}, author={Miller, Samuel R. and Jernigan, Shaphan R. and Abraham, Robert J. and Buckner, Gregory D.}, year={2024}, month={Oct} }
 @article{miller_jernigan_abraham_buckner_2023, title={Comparison of Bolus Versus Dual-Syringe Administration Systems on Glass Yttrium-90 Microsphere Deposition in an In Vitro Microvascular Hepatic Tumor Model}, volume={34}, ISSN={["1535-7732"]}, DOI={10.1016/j.jvir.2022.07.032}, abstractNote={To utilize an in vitro microvascular hepatic tumor model to compare the deposition characteristics of glass yttrium-90 microspheres using the dual-syringe (DS) and traditional bolus administration methods.The microvascular tumor model represented a 3.5-cm tumor in a 1,400-cm3 liver with a total hepatic flow of 160 mL/min and was dynamically perfused. A microcatheter was placed in a 2-mm artery feeding the tumor model and 2 additional nontarget arteries. Glass microspheres with a diameter of 20-30 μm were administered using 2 methods: (a) DS delivery at a concentration of 50 mg/mL in either a single, continuous 2-mL infusion or two 1-mL infusions and (b) bolus delivery (BD) of 100 mg of microspheres in a single 3-mL infusion.Overall, the degree of on-target deposition of the microspheres was 85% ± 11%, with no significant differences between the administration methods. Although the distal penetration into the tumor arterioles was approximately 15 mm (from the second microvascular bifurcation of the tumor model) for all the cases, the distal peak particle counts were significantly higher for the DS delivery case (approximately 5 × 105 microspheres achieving distal deposition vs 2 × 105 for the BD case). This resulted in significantly higher deposition uniformity within the tumor model (90% for the DS delivery case vs 80% for the BD case, α = 0.05).The use of this new in vitro microvascular hepatic tumor model demonstrated that the administration method can affect the deposition of yttrium-90 microspheres within a tumor, with greater distal deposition and more uniform tumor coverage when the microspheres are delivered at consistent concentrations using a DS delivery device. The BD administration method was associated with less favorable deposition characteristics of the microspheres.}, number={1}, journal={JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY}, author={Miller, Samuel R. and Jernigan, Shaphan R. and Abraham, Robert J. and Buckner, Gregory D.}, year={2023}, month={Jan}, pages={11–20} }
 @article{shah_miller_jernigan_buckner_2022, title={A Permanent Magnet Synchronous Spherical Motor for High-Mobility Servo-Actuation}, volume={10}, ISSN={["2075-1702"]}, DOI={10.3390/machines10080612}, abstractNote={The development of direct-drive spherical motors offers a potential solution to the limitations of conventional multiple degree-of-freedom (DOF) actuators, which typically utilize single-DOF joints (rotational and/or prismatic), arranged in series or parallel and powered by multiple single-DOF actuators. These configurations can be accompanied by kinematic singularities, backlash, limited power density and efficiency, and computationally expensive inverse kinematics. This paper details the design, fabrication and experimental testing of permanent magnet synchronous spherical motors (PMSSM) for multi-DOF servo-actuation. Its stator-pole arrangement is based on a Goldberg polyhedron, with each pole comprised of hexagonal or pentagonal inner and outer plates. The stator geometry and winding configurations are optimized using electromagnetic finite element analysis. A custom-made controller board includes a microcontroller, servo drivers, a wireless serial interface, and a USB PC interface. Angular orientation is sensed using an inertial measurement unit in wireless communication with the microcontroller. A PID controller is implemented and demonstrated for time-varying reference trajectories.}, number={8}, journal={MACHINES}, author={Shah, Jay A. and Miller, Samuel R. and Jernigan, Shaphan R. and Buckner, Gregory D.}, year={2022}, month={Aug} }
 @article{perrin_jernigan_thayer_howell_leary_buckner_2022, title={Sensor Fusion with Deep Learning for Autonomous Classification and Management of Aquatic Invasive Plant Species}, volume={11}, ISSN={["2218-6581"]}, DOI={10.3390/robotics11040068}, abstractNote={Recent advances in deep learning, including the development of AlexNet, Residual Network (ResNet), and transfer learning, offer unprecedented classification accuracy in the field of machine vision. A developing application of deep learning is the automated identification and management of aquatic invasive plants. Classification of submersed aquatic vegetation (SAV) presents a unique challenge, namely, the lack of a single source of sensor data that can produce robust, interpretable images across a variable range of depth, turbidity, and lighting conditions. This paper focuses on the development of a multi-sensor (RGB and hydroacoustic) classification system for SAV that is robust to environmental conditions and combines the strengths of each sensing modality. The detection of invasive Hydrilla verticillata (hydrilla) is the primary goal. Over 5000 aerial RGB and hydroacoustic images were generated from two Florida lakes via an unmanned aerial vehicle and boat-mounted sonar unit, and tagged for neural network training and evaluation. Classes included “HYDR”, containing hydrilla; “NONE”, lacking SAV, and “OTHER”, containing SAV other than hydrilla. Using a transfer learning approach, deep neural networks with the ResNet architecture were individually trained on the RGB and hydroacoustic datasets. Multiple data fusion methodologies were evaluated to ensemble the outputs of these neural networks for optimal classification accuracy. A method incorporating logic and a Monte Carlo dropout approach yielded the best overall classification accuracy (84%), with recall and precision of 84.5% and 77.5%, respectively, for the hydrilla class. The training and ensembling approaches were repeated for a DenseNet model with identical training and testing datasets. The overall classification accuracy was similar between the ResNet and DenseNet models when averaged across all approaches (1.9% higher accuracy for the ResNet vs. the DenseNet).}, number={4}, journal={ROBOTICS}, author={Perrin, Jackson E. and Jernigan, Shaphan R. and Thayer, Jacob D. and Howell, Andrew W. and Leary, James K. and Buckner, Gregory D.}, year={2022}, month={Aug} }
 @article{weisler_miller_jernigan_buckner_bryant_2020, title={Design and testing of a centrifugal fluidic device for populating microarrays of spheroid cancer cell cultures}, volume={14}, ISSN={["1754-1611"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85081898948&partnerID=MN8TOARS}, DOI={10.1186/s13036-020-0228-6}, abstractNote={In current cancer spheroid culturing methods, the transfer and histological processing of specimens grown in 96-well plates is a time consuming process. A centrifugal fluidic device was developed and tested for rapid extraction of spheroids from a 96-well plate and subsequent deposition into a molded agar receiver block. The deposited spheroids must be compact enough to fit into a standard histology cassette while also maintaining a highly planar arrangement. This size and planarity enable histological processing and sectioning of spheroids in a single section. The device attaches directly to a 96-well plate and uses a standard centrifuge to facilitate spheroid transfer. The agar block is then separated from the device and processed.Testing of the device was conducted using six full 96-well plates of fixed Pa14C pancreatic cancer spheroids. On average, 80% of spheroids were successfully transferred into the agar receiver block. Additionally, the planarity of the deposited spheroids was evaluated using confocal laser scanning microscopy. This revealed that, on average, the optimal section plane bisected individual spheroids within 27% of their mean radius. This shows that spheroids are largely deposited in a planar fashion. For rare cases where spheroids had a normalized distance to the plane greater than 1, the section plane either misses or captures a small cross section of the spheroid volume.These results indicate that the proposed device is capable of a high capture success rate and high sample planarity, thus demonstrating the capabilities of the device to facilitate rapid histological evaluation of spheroids grown in standard 96-well plates. Planarity figures are likely to be improved by adjusting agar block handling prior to imaging to minimize deformation and better preserve the planarity of deposited spheroids. Additionally, investigation into media additives to reduce spheroid adhesion to 96-well plates would greatly increase the capture success rate of this device.}, number={1}, journal={JOURNAL OF BIOLOGICAL ENGINEERING}, author={Weisler, Warren and Miller, Samuel and Jernigan, Shaphan and Buckner, Gregory and Bryant, Matthew}, year={2020}, month={Mar} }
 @article{jernigan_osborne_buckner_2020, title={Gastric artery embolization: studying the effects of catheter type and injection method on microsphere distributions within a benchtop arterial model}, volume={19}, ISSN={["1475-925X"]}, DOI={10.1186/s12938-020-00794-z}, abstractNote={Abstract Aims The objective of the study is to investigate the effect of catheter type and injection method on microsphere distributions, specifically vessel targeting accuracy. Materials and methods The study utilized three catheter types (a standard end-hole micro-catheter, a Surefire anti-reflux catheter, and an Endobar occlusion balloon catheter) and both manual and computer-controlled injection schemes. A closed-loop, dynamically pressurized surrogate arterial system was assembled to replicate arterial flow for bariatric embolization procedures. Four vessel branches immediately distal to the injection site were targeted for embolization. Embolic microspheres were injected into the model using these three catheter types and both manual and computer-controlled injections. Results Across all injection methods, the catheter effect on the proportion of microspheres to target vessels (vs. non-target vessels) was significant ( p = 0.005). The catheter effect on the number of non-target vessels embolized was nearly significant ( p = 0.059). Across all catheter types, the injection method effect was not statistically significant for either of two outcome measures (percent microspheres to target vessels: p = 0.265, number of non-target vessels embolized: p = 0.148). Conclusion Catheter type had a significant effect on targeting accuracy across all injection methods. The Endobar catheter exhibited a higher targeting accuracy in pairwise comparisons with the other two injection catheters across all injection schemes and when considering the Endobar catheter with the manifold injection method vs. each of the catheters with the manual injection method; the differences were significant in three of four analyses. The injection method effect was not statistically significant across all catheter types and when considering the Endobar catheter/Endobar manifold combination vs. Endobar catheter injections with manual and pressure-replicated methods.}, number={1}, journal={BIOMEDICAL ENGINEERING ONLINE}, author={Jernigan, Shaphan R. and Osborne, Jason A. and Buckner, Gregory D.}, year={2020}, month={Jun} }
 @article{xu_jernigan_kleinstreuer_buckner_2016, title={Solid Tumor Embolotherapy in Hepatic Arteries with an Anti-reflux Catheter System}, volume={44}, ISSN={["1573-9686"]}, DOI={10.1007/s10439-015-1411-7}, abstractNote={Unresectable hepatoma accounts for the majority of malignant liver tumor cases for which embolization therapy is considered a viable treatment option. However, the potential risk of aberrant particle deposition in non-target regions could cause severe side-effects, alongside diminished efficacy. A computational model has been developed to analyze the particle-hemodynamics before and after deployment of an FDA-approved anti-reflux catheter. The catheter features a retractable, porous cone-like tip designed to allow forward blood flow while preventing microsphere reflux. A patient-specific hepatic artery system, with different daughter branches connected to a liver tumor, was chosen as a representative test bed. In vitro as well as in vivo measurements were used to validate the computer simulation model. The model captures the effect of tip-deployment on blood perfusion and pressure drop in an interactive manner under physiologically realistic conditions. A relationship between the pressure drop and embolization level was established, which can be used to provide clinicians with real-time information on the best infusion-stop point. However, the results show that the present procedure for embolization of downstream vessels which feed a tumor is quite arbitrary. Nevertheless, a method to recycle aberrant particles captured by the deployed tip was proposed to minimize side-effects.}, number={4}, journal={ANNALS OF BIOMEDICAL ENGINEERING}, author={Xu, Zelin and Jernigan, Shaphan and Kleinstreuer, Clement and Buckner, Gregory D.}, year={2016}, month={Apr}, pages={1036–1046} }
 @article{hoven_lam_jernigan_bosch_buckner_2015, title={Innovation in catheter design for intra-arterial liver cancer treatments results in favorable particle-fluid dynamics}, volume={34}, DOI={10.1186/s13046-015-0188-8}, abstractNote={Liver tumors are increasingly treated with radioembolization. Here, we present first evidence of catheter design effect on particle-fluid dynamics and downstream branch targeting during microsphere administrations.A total of 7 experiments were performed in a bench-top model of the hepatic arterial vasculature with recreated hemodynamics. Fluorescent microspheres and clinically used holmium microspheres were administered with a standard microcatheter (SMC) and an anti-reflux catheter (ARC) positioned at the same level along the longitudinal vessel axis. Catheter-related particle flow dynamics were analyzed by reviewing video recordings of UV-light illuminated fluorescent microsphere administrations. Downstream branch distribution was analyzed by quantification of collected microspheres in separate filters for two first-order branches. Mean deviation from a perfectly homogenous distribution (DHD) was used to compare the distribution homogeneity between catheter types.The SMC administrations demonstrated a random off-centered catheter position (in 71 % of experiments), and a laminar particle flow pattern with an inhomogeneous downstream branch distribution, dependent on catheter position and injection force. The ARC administrations demonstrated a fixed centro-luminal catheter position, and a turbulent particle flow pattern with a more consistent and homogenous downstream branch distribution. Quantitative analyses confirmed a significantly more homogeneous distribution with the ARC; the mean DHD was 40.85 % (IQR 22.76 %) for the SMC and 15.54 % (IQR 6.46 %) for the ARC (p = 0.047).Catheter type has a significant impact on microsphere administrations in an in-vitro hepatic arterial model. A within-patient randomized controlled trial has been initiated to investigate clinical catheter-related effects during radioembolization treatment.}, journal={Journal of Experimental & Clinical Cancer Research}, author={Hoven, A. F. and Lam, M. G. E. H. and Jernigan, S. and Bosch, M. A. A. J. and Buckner, G. D.}, year={2015} }
 @article{jernigan_osborne_mirek_buckner_2015, title={Selective Internal Radiation Therapy: Quantifying Distal Penetration and Distribution of Resin and Glass Microspheres in a Surrogate Arterial Model}, volume={26}, ISSN={1051-0443}, url={http://dx.doi.org/10.1016/J.JVIR.2015.02.022}, DOI={10.1016/j.jvir.2015.02.022}, abstractNote={To experimentally investigate the effects of microsphere density and diameter on distal penetration.A surrogate hepatic arterial system was developed to replicate the hemodynamics (pressures, flow rates, pulsatile flow characteristics) and anatomic geometry (vessel diameters) proximal and distal to the microsphere injection point. A planar tumor model, placed distal to the injection point, allowed visualization of deposited microspheres. Bland resin and glass microspheres, with physical characteristics approximating the characteristics of commercially available products, were injected into the surrogate system. Microsphere type, injection rate, systemic flow rate, and tumor model inclination were varied among tests (glass, n = 7; resin, n = 6) with replicates for 2 conditions. After injection, 254 micrographs were obtained at previously defined locations throughout the tumor model to document microsphere distributions. Average microsphere distributions and mass measurements of microspheres collected at the tumor outlet were analyzed to quantify distal penetration for each case.Across all test conditions, average penetration depths of resin microspheres were higher compared with glass microspheres (45.1 cm ± 11.8 vs 22.3 cm ± 9.9). The analysis of variance indicated that the observed difference between microsphere type (glass vs resin) was significant (P = .005, df = 1,2). The observed distance means did not differ significantly across flow rate or inclination angle.Penetration depths of resin microspheres were significantly higher than penetration depths of glass microspheres in the surrogate hepatic arterial system.}, number={6}, journal={Journal of Vascular and Interventional Radiology}, publisher={Elsevier BV}, author={Jernigan, Shaphan R. and Osborne, Jason A. and Mirek, Christopher J. and Buckner, Gregory}, year={2015}, month={Jun}, pages={897–904.e2} }
 @inproceedings{jernigan_fortney_fahmy_buckner_2012, title={Implementing effective low-cost laboratory experiments into a distance engineering program}, DOI={10.1115/imece2010-40938}, abstractNote={This paper details the successful and inexpensive implementation of remote laboratory experiments into a control systems course using readily available hardware and software. The custom-made experiments include an inverted pendulum, a platform leveling system, a ball and beam apparatus, and an aerodynamic beach ball levitation system, each implemented in a separate course offering. With each laboratory, the control objective is to regulate a physical parameter, (pendulum angle, platform orientation, ball position, etc.) by manipulating voltage to a drive component (DC motor, linear actuator, blower, etc.). Engineering software commonly used in controls courses (MATLAB/Simulink and LabView) coupled with dedicated hardware (xPC Target and NI Compact Rio) provide the controller platforms, while Microsoft NetMeeting and standard Internet video conferencing equipment are used to interface the distance-learning students with the laboratory equipment. Both local students at North Carolina State University’s campus in Raleigh and distance students at the University of North Carolina at Asheville and Craven Community College in Havelock, NC complete the laboratory experiments. In a student survey, distance students participating in the remote labs rated the experience as favorably as local students. Course grades, including design project grades, were similar between the two groups.}, booktitle={Proceedings of the ASME International Mechanical Engineering Congress and Exposition (IMECE 2010), vol 6}, author={Jernigan, S. R. and Fortney, B. and Fahmy, Y. and Buckner, G. D.}, year={2012}, pages={87–94} }
 @article{jernigan_fahmy_buckner_2009, title={Implementing a Remote Laboratory Experience Into a Joint Engineering Degree Program: Aerodynamic Levitation of a Beach Ball}, volume={52}, ISSN={["1557-9638"]}, DOI={10.1109/TE.2008.924217}, abstractNote={This paper details a successful and inexpensive implementation of a remote laboratory into a distance control systems course using readily available hardware and software. The physical experiment consists of a beach ball and a dc blower; the control objective is to make the height of the aerodynamically levitated beach ball track a reference trajectory by manipulating the voltage to the blower. MATLAB/Simulink coupled with xPC target serve as the controller platform, while microsoft netmeeting and standard Internet video conferencing equipment are used to interface the distance-learning students with the laboratory equipment. Both local students at North Carolina State University's campus in Raleigh and distance students at the University of North Carolina at Asheville completed the laboratory experiment. In a student survey, distance students participating in the lab remotely rated the experience as favorably as local students. Course grades, including the design project grade, were similar between the two groups.}, number={2}, journal={IEEE TRANSACTIONS ON EDUCATION}, author={Jernigan, Shaphan R. and Fahmy, Yusef and Buckner, Gregory D.}, year={2009}, month={May}, pages={205–213} }
 @article{bean_chanoit_jernigan_bolotin_osborne_buckner_2008, title={Evaluation of a novel atrial retractor for exposure of the mitral valve in a porcine model}, volume={136}, ISSN={["1097-685X"]}, DOI={10.1016/j.jtcvs.2008.08.030}, abstractNote={ObjectivesTo describe a novel atrial retractor and compare 2 methods of intraoperative left atrial retraction for minimally invasive mitral valve repair.MethodsLeft atrial retraction was performed on 5 swine cadavers to evaluate performance (percent of mitral valve annulus accessible), complications encountered, ease of use, and surgical time for the minimally invasive atrial retractor and a HeartPort atrial retractor.ResultsEstimated accessibilities were 93.0% (standard error = 3.2) and 92.7% (standard error = 3.3) for the HeartPort and minimally invasive atrial retractor retractors, respectively, with a difference of 0.3% (standard error = 2.2%, P = .8832, df = 34). Tissue damage occurred in 1 case for the minimally invasive atrial retractor and 2 cases for the HeartPort retractor. The mean surgical times for retractor placement and mitral valve annulus exposure were 107.4 and 39.2 seconds for the HeartPort and minimally invasive atrial retractor retractors, respectively, with a difference of 68.2 seconds (P = .0092, df = 4).ConclusionsThe minimally invasive atrial retractor is a suitable alternative for atrial retraction compared with standard techniques of retraction. It provides comparable exposure of the mitral valve annulus, is less time consuming to place, provides subjectively more working volume within the left atrium, and has the advantage of minimal atriotomy incision length and customizable retraction. To describe a novel atrial retractor and compare 2 methods of intraoperative left atrial retraction for minimally invasive mitral valve repair. Left atrial retraction was performed on 5 swine cadavers to evaluate performance (percent of mitral valve annulus accessible), complications encountered, ease of use, and surgical time for the minimally invasive atrial retractor and a HeartPort atrial retractor. Estimated accessibilities were 93.0% (standard error = 3.2) and 92.7% (standard error = 3.3) for the HeartPort and minimally invasive atrial retractor retractors, respectively, with a difference of 0.3% (standard error = 2.2%, P = .8832, df = 34). Tissue damage occurred in 1 case for the minimally invasive atrial retractor and 2 cases for the HeartPort retractor. The mean surgical times for retractor placement and mitral valve annulus exposure were 107.4 and 39.2 seconds for the HeartPort and minimally invasive atrial retractor retractors, respectively, with a difference of 68.2 seconds (P = .0092, df = 4). The minimally invasive atrial retractor is a suitable alternative for atrial retraction compared with standard techniques of retraction. It provides comparable exposure of the mitral valve annulus, is less time consuming to place, provides subjectively more working volume within the left atrium, and has the advantage of minimal atriotomy incision length and customizable retraction.}, number={6}, journal={JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY}, author={Bean, Eric and Chanoit, Guillaume and Jernigan, Shaphan and Bolotin, Gil and Osborne, Jason and Buckner, Gregory}, year={2008}, month={Dec}, pages={1492–1495} }
 @article{jernigan_buckner_eischen_2007, title={Finite element modeling of the left atrium to facilitate the design of an endoscopic atrial retractor}, volume={129}, ISSN={["1528-8951"]}, DOI={10.1115/1.2801650}, abstractNote={Abstract With the worldwide prevalence of cardiovascular diseases, much attention has been focused on simulating the characteristics of the human heart to better understand and treat cardiac disorders. The purpose of this study is to build a finite element model of the left atrium (LA) that incorporates detailed anatomical features and realistic material characteristics to investigate the interaction of heart tissue and surgical instruments. This model is used to facilitate the design of an endoscopically deployable atrial retractor for use in minimally invasive, robotically assisted mitral valve repair. Magnetic resonance imaging (MRI) scans of a pressurized explanted porcine heart were taken to provide a 3D solid model of the heart geometry, while uniaxial tensile tests of porcine left atrial tissue were conducted to obtain realistic material properties for noncontractile cardiac tissue. A finite element model of the LA was constructed using ANSYS™ Release 9.0 software and the MRI data. The Mooney–Rivlin hyperelastic material model was chosen to characterize the passive left atrial tissue; material constants were derived from tensile test data. Finite element analysis (FEA) models of a CardioVations Port Access™ retractor and a prototype endoscopic retractor were constructed to simulate interaction between each instrument and the LA. These contact simulations were used to compare the quality of retraction between the two instruments and to optimize the design of the prototype retractor. Model accuracy was verified by comparing simulated cardiac wall deflections to those measured by MRI. FEA simulations revealed that peak forces of approximately 2.85N and 2.46N were required to retract the LA using the Port Access™ and prototype retractors, respectively. These forces varied nonlinearly with retractor blade displacement. Dilation of the atrial walls and rigid body motion of the chamber were approximately the same for both retractors. Finite element analysis is shown to be an effective tool for analyzing instrument/tissue interactions and for designing surgical instruments. The benefits of this approach to medical device design are significant when compared to the alternatives: constructing prototypes and evaluating them via animal or clinical trials.}, number={6}, journal={JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME}, author={Jernigan, S. R. and Buckner, G. D. and Eischen, J. W.}, year={2007}, month={Dec}, pages={825–837} }