@article{cox laws_wood_harrysson_traverson_2023, title={Novel 3D Custom-Made Silicone Tumor Model as a Support for Teaching Surgical Oncology Principles}, volume={6}, ISSN={["1943-7218"]}, DOI={10.3138/jvme-2022-0148}, abstractNote={ Alternative laboratory teaching methods are becoming increasingly desirable and effective in medical education environments. While ethical concerns associated with the use of live animals in terminal surgery laboratories have been reduced with cadaveric models, availability, and lack of pathology can limit their ability to adequately convey surgical principles and replicate clinical training. We have developed a three-dimensional (3D) custom-made silicone soft tissue tumor model using 3D-printed molds derived from canine soft tissue sarcoma computed tomography images. This novel teaching model allows users to apply surgical oncology principles and perform basic technical tasks such as incisional biopsy, margin demarcation, marginal and wide surgical excision, and inking of surgical margins. A large cohort of students in addition to a small number of professional veterinarians at different levels of specialty training followed the laboratory guidelines and evaluated the simulated tumor model based on a qualitative survey. All participants were able to successfully complete the practical training. The model also allowed the students to identify and correct technical errors associated with biopsy sampling and margin dissection, and to understand the clinical impacts related to those errors. Face and content validity of the model were assessed using Likert-style questionnaires with overall average instructors’ scores of 3.8/5 and 4.6/5, respectively. Content validity assessment of the model by the students approximated instructors’ evaluation with an overall average score of 4.4/5. This model development emphasizes the efficacy of alternative non-cadaveric laboratory teaching tools and could become a valuable aid in the veterinary curricula. }, journal={Journal of Veterinary Medical Education}, author={Cox Laws, A and Wood, M and Harrysson, O and Traverson, M}, year={2023} }
 @article{chayasombat_promoppatum_srisawadi_tanprayoon_tapracharoen_tummake_ihama_mizuguchi_sato_suga_et al._2024, title={Single track formation of TiC reinforced Inconel 718 metal matrix composites using selective laser melting process}, volume={2}, ISSN={["1433-3015"]}, DOI={10.1007/s00170-024-13260-0}, journal={INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY}, author={Chayasombat, Bralee and Promoppatum, Patcharapit and Srisawadi, Sasitorn and Tanprayoon, Dhritti and Tapracharoen, Krisda and Tummake, Boonyakorn and Ihama, Masahiro and Mizuguchi, Yuta and Sato, Yuji and Suga, Tetsuo and et al.}, year={2024}, month={Feb} }
 @article{chambers_traverson_neal_konala_harrysson_2023, title={Performances of novel custom 3D-printed cutting guide in canine caudal maxillectomy: a cadaveric study}, volume={10}, ISSN={["2297-1769"]}, DOI={10.3389/fvets.2023.1127025}, abstractNote={IntroductionCaudal maxillectomies are challenging procedures for most veterinary surgeons. Custom guides may allow the procedure to become more accessible.MethodsA cadaveric study was performed to evaluate the accuracy and efficiency of stereolithography guided (3D-printed) caudal maxillectomy. Mean absolute linear deviation from planned to performed cuts and mean procedure duration were compared pairwise between three study groups, with 10 canine cadaver head sides per group: 3D-printed guided caudal maxillectomy performed by an experienced surgeon (ESG) and a novice surgery resident (NSG), and freehand procedure performed by an experienced surgeon (ESF).ResultsAccuracy was systematically higher for ESG versus ESF, and statistically significant for 4 of 5 osteotomies (p < 0.05). There was no statistical difference in accuracy between ESG and NSG. The highest absolute mean linear deviation for ESG was <2 mm and >5 mm for ESF. Procedure duration was statistically significantly longer for ESG than ESF (p < 0.001), and for NSG than ESG (p < 0.001).DiscussionSurgical accuracy of canine caudal maxillectomy was improved with the use of our novel custom cutting guide, despite a longer duration procedure. Improved accuracy obtained with the use of the custom cutting guide could prove beneficial in achieving complete oncologic margins. The time increase might be acceptable if hemorrhage can be adequately controlled in vivo. Further development in custom guides may improve the overall efficacy of the procedure.}, journal={Frontiers in Veterinary Science}, author={Chambers, A. and Traverson, M. and Neal, S. and Konala, S. and Harrysson, O.}, year={2023} }
 @article{houser_shashaani_harrysson_jeon_2023, title={Predicting additive manufacturing defects with robust feature selection for imbalanced data}, volume={5}, ISSN={["2472-5862"]}, url={https://doi.org/10.1080/24725854.2023.2207633}, DOI={10.1080/24725854.2023.2207633}, abstractNote={Promptly predicting defects during an additive manufacturing process using only copious log data provides many advantages, albeit with computational limitations. We focus on predicting defects during electron beam melting with the black box nature of the manufacturing machine. For an accurate prediction of defects, which are rare (<2%), we extract temporal information to track abnormalities and formulate a feature selection algorithm that maximizes the expected value of a cost-sensitive accuracy. Correct identification of features responsible for the defects increases predictive power and informs manufacturers of potential corrective/preventive actions for process improvement. We solve the feature selection through resampling strategies integrated with ensemble procedures to handle data uncertainty and imbalance. Exploiting data uncertainty in our search leads to finding robust features with consistent predictive power. Our proposed methodology shows a 43% improvement in predicting defects (recall) without losing precision. Beyond additive manufacturing, this methodology has general application for rare-event prediction and imbalanced datasets.}, journal={IISE TRANSACTIONS}, author={Houser, Ethan and Shashaani, Sara and Harrysson, Ola and Jeon, Yongseok}, year={2023}, month={May} }
 @article{weflen_hamilton_sorondo_harrysson_frank_rivero_2022, title={Evaluating interlayer gaps in friction stir spot welds for rapid tooling applications}, volume={7}, ISSN={["2472-5862"]}, DOI={10.1080/24725854.2022.2091184}, abstractNote={Abstract Potential for a rapid hybrid additive/subtractive manufacturing technique capable of generating large aluminum components with deep geometrical features exists if, for example, layers of aluminum plates can be deposited and held in place using friction stir welding followed by machining. However, when plates of aluminum are friction stir spot welded together, adjacent material can deform causing a gap between layers. This research investigates how friction stir tool geometry affects the formation of interlayer gaps and the lap shear strength of the weld. For this purpose, residual stresses and microhardness were measured to characterize the weld formation process. While friction stir welding of 6061 aluminum bar stock was carried out on a machining center with three different pin diameters (5.7, 6.4, 7.0 mm) and two pin lengths (8.9, 10.2 mm). In general, outcomes of the research show that lap shear strength trends upward with increasing pin diameter but does not show a strong relation to the pin length. Interlayer gap size increases with pin length, but does not show a clear trend with pin diameter. Compressive residual stresses were observed on the weld shoulder with no significant variations occurring among the studied stir tool geometries. No significant change was measured in microhardness values when the pin length or shoulder diameter were changed, suggesting that the increase in lap shear strength is due to a change in weld cross-section instead of a material property change. This research will guide friction stir tool geometry selection for this hybrid manufacturing process and can be applied more broadly to any application where material deformation around a weld is undesirable.}, journal={IISE TRANSACTIONS}, author={Weflen, Eric and Hamilton, Jakob D. and Sorondo, Samantha and Harrysson, Ola L. A. and Frank, Matthew C. and Rivero, Iris V}, year={2022}, month={Jul} }
 @article{altug-peduk_dilibal_harrysson_ozbek_2021, title={Experimental Investigation on the EBM-Based Additively Manufactured Prismatic Nickel-Titanium SMA Components}, volume={62}, ISSN={["1934-970X"]}, DOI={10.3103/S1067821221030020}, number={3}, journal={RUSSIAN JOURNAL OF NON-FERROUS METALS}, author={Altug-Peduk, Gozde S. and Dilibal, Savas and Harrysson, Ola and Ozbek, Sunullah}, year={2021}, month={May}, pages={357–367} }
 @article{hauser_king_wysk_harrysson_2021, title={Resource planning for direct fabrication of customized orthopedic implants using EBM technology}, volume={60}, ISSN={["1878-6642"]}, url={https://doi.org/10.1016/j.jmsy.2021.07.003}, DOI={10.1016/j.jmsy.2021.07.003}, abstractNote={Medical innovations and patient expectations are pushing healthcare toward personalized medicine. In orthopedics, the concept of patient-specific implants could be economically realized with the use of additive manufacturing. Knee and hip replacements are some of the most common musculoskeletal procedures performed in the United States. Joint replacement implants are typically offered in standard sizes and geometries. The mass customization of theses prostheses, however, can improve patient outcomes and reduce medical costs. Mass customization is not economically feasible with traditional manufacturing methods because of the high fixed tooling costs for each geometry. The freedom of design offered by additive manufacturing presents a viable production alternative for unique personal geometry. The objective of this paper is to develop two new analytic models that can be used to investigate a complex additive manufacturing supply chain. The focus of the model is to provide planning tools and a methodology for the direct production of customized orthopedic implants using electron beam melting, an additive manufacturing technology. First, a production model for an additive manufacturing-based system is created. Next, resource planning for a single customized implant system is performed using a simulation model. A queuing model is developed for rapid systems analysis. The staffing requirement predictions of the two models align closely for production of a singular, customized implant. A detailed systems analysis of an additive manufacturing supply chain is conducted to illustrate the use of these models. The queueing model is analytically tractable, so it is extended to describe the production of standard and customized versions of multiple implant families.}, journal={JOURNAL OF MANUFACTURING SYSTEMS}, publisher={Elsevier BV}, author={Hauser, Margaret and King, Russell and Wysk, Richard and Harrysson, Ola}, year={2021}, month={Jul}, pages={500–511} }
 @article{mariani_zlotnick_harrysson_marcellin-little_malinak_gavitt_guevar_2021, title={Accuracy of three-dimensionally printed animal-specific drill guides for implant placement in canine thoracic vertebrae: A cadaveric study}, volume={50}, ISSN={["1532-950X"]}, url={https://doi.org/10.1111/vsu.13557}, DOI={10.1111/vsu.13557}, abstractNote={AbstractObjectiveTo assess the accuracy of three‐dimensionally (3‐D) printed drill guides in constraining the trajectory of drill tracts for implants in canine thoracic vertebrae.Study designExperimental ex vivo study.Sample populationFive canine thoracic vertebral column specimens.MethodsGuides to constrain drill trajectories were designed on the basis of computed tomographic (CT) imaging of six thoracic vertebrae (T8‐T13) and were 3‐D printed. The guides were used to create drill tracts in these vertebrae by both an experienced and a novice surgeon, and CT imaging was repeated. The entry point and angulation of actual and planned drill tracts were compared for both surgeons. Unintended cortical violations were also assessed by using a modified Zdichavsky classification.ResultsFifty‐eight drill tracts were created in 30 vertebrae. Mean entry point deviation was 1.4 mm (range, 0.4‐3.4), and mean angular deviation was 5.1° (range, 1.5°‐10.8°). There were no differences between surgeons in entry point deviation (P = .07) or angular deviation (P = .22). There were no unintended cortical bone violations, and all drill tracts were classified as modified Zdichavsky grade I.ConclusionThe 3‐D printed guides used in the current study yielded drill tracts with small linear and angular errors from intended paths and 100% accuracy for placement within vertebral pedicles and bodies. This technique was conveniently used by both an experienced and a novice surgeon.Clinical significanceThis technique might be immediately applicable to clinical cases requiring thoracic vertebral stabilization and may allow safe and accurate implant placement for surgeons with varying experience levels.}, number={2}, journal={VETERINARY SURGERY}, publisher={Wiley}, author={Mariani, Christopher L. and Zlotnick, Joshua A. and Harrysson, Ola and Marcellin-Little, Denis J. and Malinak, Kristen and Gavitt, Ashley and Guevar, Julien}, year={2021}, month={Feb}, pages={294–302} }
 @article{hamilton_ramesh_harrysson_rock_rivero_2021, title={Cryogenic mechanical alloying of aluminum matrix composites for powder bed fusion additive manufacturing}, volume={55}, ISSN={["1530-793X"]}, DOI={10.1177/0021998320957698}, abstractNote={ Cryogenic mechanical alloying (cryomilling) was employed to fabricate aluminum matrix composite powder feedstock for additive manufacturing. The high energy milling of the powder system induces a homogenous distribution of reinforcement particles in the matrix powder by recurrent fracture and cold welding. In this study, aluminum matrix composite feedstock were produced via different cryomilling techniques at varying compositions, powder charges, and milling times. As-milled powders were characterized for particle size distribution, morphology, and homogeneity. Resultant powder demonstrated varying characteristics correlated to milling parameters. Powder metallurgy samples were also fabricated to understand as-sintered reinforcement distribution and the resultant strengthening. This research provides an indication of cryomilling capabilities to become an effective method for custom alloy powder production for powder bed fusion additive manufacturing. }, number={5}, journal={JOURNAL OF COMPOSITE MATERIALS}, author={Hamilton, Jakob D. and Ramesh, Srikanthan and Harrysson, Ola L. A. and Rock, Christopher D. and Rivero, Iris V}, year={2021}, month={Mar}, pages={641–651} }
 @article{webster_marcellin-little_koballa_stallrich_harrysson_2019, title={Evaluation of the geometric accuracy of computed tomography and microcomputed tomography of the articular surface of the distal portion of the radius of cats}, volume={80}, ISSN={["1943-5681"]}, DOI={10.2460/ajvr.80.10.976}, abstractNote={Abstract

OBJECTIVE
To evaluate accuracy of articular surfaces determined by use of 2 perpendicular CT orientations, micro-CT, and laser scanning.


SAMPLE
23 cat cadavers.


PROCEDURES
Images of antebrachia were obtained by use of CT (voxel size, 0.6 mm) in longitudinal orientation (CTLO images) and transverse orientation (CTTO images) and by use of micro-CT (voxel size, 0.024 mm) in a longitudinal orientation. Images were reconstructed. Craniocaudal and mediolateral length, radius of curvature, and deviation of the articular surface of the distal portion of the radius of 3-D renderings for CTLO, CTTO, and micro-CT images were compared with results of 3-D renderings acquired with a laser scanner (resolution, 0.025 mm).


RESULTS
Measurement of CTLO and CTTO images overestimated craniocaudal and mediolateral length of the articular surface by 4% to 10%. Measurement of micro-CT images underestimated craniocaudal and mediolateral length by 1%. Measurement of CTLO and CTTO images underestimated mediolateral radius of curvature by 15% and overestimated craniocaudal radius of curvature by > 100%; use of micro-CT images underestimated them by 3% and 5%, respectively. Mean ± SD surface deviation was 0.26 ± 0.09 mm for CTLO images, 0.30 ± 0.28 mm for CTTO images, and 0.04 ± 0.02 mm for micro-CT images.


CONCLUSIONS AND CLINICAL RELEVANCE
Articular surface models derived from CT images had dimensional errors that approximately matched the voxel size. Thus, CT cannot be used to plan conforming arthroplasties in small joints and could lack precision when used to plan the correction of a limb deformity or repair of a fracture.
}, number={10}, journal={AMERICAN JOURNAL OF VETERINARY RESEARCH}, author={Webster, Caroline E. and Marcellin-Little, Denis J. and Koballa, Erin M. and Stallrich, Jonathan W. and Harrysson, Ola L. A.}, year={2019}, month={Oct}, pages={976–984} }
 @article{mahbooba_thorsson_unosson_skoglund_west_horn_rock_vogli_harrysson_2018, title={Additive manufacturing of an iron-based bulk metallic glass larger than the critical casting thickness}, volume={11}, ISSN={["2352-9407"]}, DOI={10.1016/j.apmt.2018.02.011}, abstractNote={Fe-based bulk metallic glasses (BMG) are of increasing research interest, driven in part by a unique combination of mechanical, magnetic and chemical properties. However, the maximum thickness and geometry of BMGs achievable in traditional manufacturing processes is limited. This work examines the capabilities of laser based powder bed additive manufacturing (AM) to produce relatively large Fe-based bulk metallic glass specimens. AM fabricated specimens exceed the critical casting thickness of the material by a factor of 15 or more in all dimensions. Resulting microstructural and mechanical properties are reported. Despite decreasing quench effect with increasing build thickness, X-ray diffraction analysis suggests that a fully amorphous structure was maintained throughout the build. However, a low concentration of sparsely distributed nano-grain clusters was discovered using a high-resolution electron backscatter diffraction scan. The results pave the way for novel applications of metallic glasses achievable through appropriate material design and optimization of existing additive manufacturing processes.}, journal={APPLIED MATERIALS TODAY}, author={Mahbooba, Zaynab and Thorsson, Lena and Unosson, Mattias and Skoglund, Peter and West, Harvey and Horn, Timothy and Rock, Christopher and Vogli, Evelina and Harrysson, Ola}, year={2018}, month={Jun}, pages={264–269} }
 @article{seifi_dahar_aman_harrysson_beuth_lewandowski_2018, title={Correction to: Evaluation of Orientation Dependence of Fracture Toughness and Fatigue Crack Propagation Behavior of As-Deposited ARCAM EBM Ti-6Al-4V}, volume={70}, ISSN={1047-4838 1543-1851}, url={http://dx.doi.org/10.1007/S11837-018-2736-0}, DOI={10.1007/S11837-018-2736-0}, abstractNote={There was a typographical error in Fig. 2b in the original publication of this article. It has been corrected in the image below.}, number={3}, journal={JOM}, publisher={Springer Science and Business Media LLC}, author={Seifi, Mohsen and Dahar, Matthew and Aman, Ron and Harrysson, Ola and Beuth, Jack and Lewandowski, John J.}, year={2018}, month={Jan}, pages={436–436} }
 @article{basinger_keough_webster_wysk_martin_harrysson_2018, title={Development of a modular computer-aided process planning (CAPP) system for additive-subtractive hybrid manufacturing of pockets, holes, and flat surfaces}, volume={96}, ISSN={["1433-3015"]}, DOI={10.1007/s00170-018-1674-x}, number={5-8}, journal={INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY}, author={Basinger, Katie L. and Keough, Carter B. and Webster, Caroline E. and Wysk, Richard A. and Martin, Thomas M. and Harrysson, Ola L.}, year={2018}, month={May}, pages={2407–2420} }
 @article{spearman_irin_ramesh_rivero_green_harrysson_2019, title={Effect of pseudomonas lipase enzyme on the degradation of polycaprolactone/polycaprolactone-polyglycolide fiber blended nanocomposites}, volume={68}, ISBN={1563-535X}, DOI={10.1080/00914037.2018.1445633}, abstractNote={ABSTRACT This study describes the interaction resulting from adding pseudomonas lipase (PS) enzyme to polycaprolactone-based composites designed for orthopedic applications. The biopolymer composite evaluated in this study consists of electrospun polycaprolactone (PCL)/polyglycolide (PGA) blended fibers impregnated with double stranded deoxyribonucleic acid wrapped single-walled carbon nanotubes encapsulated by a PCL matrix. PS enzyme was used to catalyze the degradation of PCL-based biocomposites. PCL present in the biocomposites showed considerable degradation in 4 weeks in the presence of the enzyme, exhibiting a contrast to hydrolytic degradation which lasts several years. PGA-consisting fibers degraded completely within one week of exposure to the enzyme. GRAPHICAL ABSTRACT}, number={7}, journal={INTERNATIONAL JOURNAL OF POLYMERIC MATERIALS AND POLYMERIC BIOMATERIALS}, author={Spearman, Shayla S. and Irin, Fahmida and Ramesh, Srikanthan and Rivero, Iris V. and Green, Micah J. and Harrysson, Ola L. A.}, year={2019}, pages={360–367} }
 @article{ruppert_harrysson_marcellin-little_dahners_weinhold_2018, title={Improved osseointegration with as-built electron beam melted textured implants and improved peri-implant bone volume with whole body vibration}, volume={58}, ISSN={["1873-4030"]}, DOI={10.1016/j.medengphy.2018.05.003}, abstractNote={Transcutaneous osseointegrated prostheses provide stable connections to the skeleton while eliminating skin lesions experienced with socket prosthetics. Additive manufacturing can create custom textured implants capable of interfacing with amputees' residual bones. Our objective was to compare osseointegration of textured surface implants made by electron beam melting (EBM), an additive manufacturing process, to machine threaded implants. Whole body vibration was investigated to accelerate osseointegration. Two cohorts of Sprague-Dawley rats received bilateral, titanium implants (EBM vs. threaded) in their tibiae. One cohort comprising five groups vibrated at 45 Hz: 0.0 (control), 0.15, 0.3, 0.6 or 1.2 g was followed for six weeks. Osseointegration was evaluated through torsional testing and bone volume fraction (BV/TV). A second cohort, divided into two groups (control and 0.6 g), was followed for 24 days and evaluated for resonant frequency, bone-implant contact (BIC) and fluorochrome labeling. The EBM textured implants exhibited significantly improved mechanical stability independent of vibration, highlighting the benefits of using EBM to produce custom textured surfaces. Bone formation on and around the EBM textured implants increased compared to machined implants, as seen by BIC and fluorescence. No difference in torque, BIC or fluorescence among vibration levels was detected. BV/TV significantly increased at 0.6 g compared to control for both implant types.}, journal={MEDICAL ENGINEERING & PHYSICS}, author={Ruppert, David S. and Harrysson, Ola L. A. and Marcellin-Little, Denis J. and Dahners, Laurence E. and Weinhold, Paul S.}, year={2018}, month={Aug}, pages={64–71} }
 @article{eldesouky_harrysson_west_elhofy_2017, title={Electron beam melted scaffolds for orthopedic applications}, volume={17}, ISSN={2214-8604}, url={http://dx.doi.org/10.1016/J.ADDMA.2017.08.005}, DOI={10.1016/J.ADDMA.2017.08.005}, abstractNote={Ti6Al4V porous scaffolds of two unit cell geometries (reentrant and cubic) were investigated as candidates for load-bearing biomedical applications. Samples were fabricated using an Arcam A2 electron beam melting (EBM) machine and evaluated for geometric deviation from the original CAD design using a digital optical microscope. The mass and bounding volume of each sample were also measured to calculate the resulting relative density. The scaffolds were loaded in compression in the build direction to determine the relative modulus of elasticity and ultimate compressive load. Experimental results were used to calculate the Gibson and Ashby relation parameters for the studied unit cell geometries. The results suggest that samples with the cubic unit cell geometries, with struts oriented at an angle of 45° to the loading direction, exhibited higher stiffness than samples with the reentrant unit cell geometry at equivalent relative densities. A cubic scaffold is verified to withstand high compressive loads (more than 71 kN) while having an approximate pore size in the range of 0.6 mm. These characteristics demonstrate its suitability for load bearing biomedical implants.}, journal={Additive Manufacturing}, publisher={Elsevier BV}, author={Eldesouky, Ibrahim and Harrysson, Ola and West, Harvey and Elhofy, Hassan}, year={2017}, month={Oct}, pages={169–175} }
 @article{eldesouky_harrysson_marcellin-little_west_el-hofy_2017, title={Pre-clinical evaluation of the mechanical properties of a low-stiffness cement-injectable hip stem}, volume={41}, ISSN={0309-1902 1464-522X}, url={http://dx.doi.org/10.1080/03091902.2017.1394391}, DOI={10.1080/03091902.2017.1394391}, abstractNote={Abstract In total hip arthroplasty (THA), the femoral stem can be fixed with or without bone cement. Cementless stem fixation is recommended for young and active patients as it eliminates the risk of loss of fixation at the bone–cement and cement–implant interfaces. Cementless fixation, however, suffers from a relatively high early revision rate. In the current research, a novel low-stiffness hip stem was designed, fabricated and tested. The stem design provided the option to inject biodegradable bone cement that could enhance initial stem stability. The stem was made of Ti6Al4V alloy. The proximal portion of the stem was porous, with cubic cells. The stem was fabricated using electron beam melting (EBM) technology and tested in compression and bending. Finite-element analysis was used to evaluate stem performance under a dynamic load representing a stair descending cycle and compare it to the performance of a solid stem with similar geometry. The von Mises stresses and maximum principal strains generated within the bone increased after porous stem insertion compared to solid stem insertion. The low-modulus stem tested in this study has acceptable mechanical properties and generates strain patterns in bone that appear compatible with clinical use.}, number={8}, journal={Journal of Medical Engineering & Technology}, publisher={Informa UK Limited}, author={Eldesouky, Ibrahim and Harrysson, Ola and Marcellin-Little, Denis J. and West, Harvey and El-Hofy, Hassan}, year={2017}, month={Nov}, pages={681–691} }
 @article{smith_marcellin-little_harrysson_griffith_2017, title={Three-dimensional assessment of curvature, torsion, and canal flare index of the humerus of skeletally mature nonchondrodystrophic dogs}, volume={78}, DOI={10.2460/ajvr.78.10.1140}, abstractNote={Abstract
OBJECTIVE To assess 3-D geometry of the humerus of dogs and determine whether the craniocaudal canal flare index (CFI) is associated with specific geometric features.
SAMPLE CT images (n = 40) and radiographs (38) for 2 groups of skeletally mature nonchondrodystrophic dogs.
PROCEDURES General dimensions (length, CFI, cortical thickness, and humeral head offset), curvature (shaft, humeral head, and glenoid cavity), version (humeral head and greater tubercle), and torsion were evaluated on CT images. Dogs were allocated into 3 groups on the basis of the craniocaudal CFI, and results were compared among these 3 groups. The CT measurements were compared with radiographic measurements obtained for another group of dogs.
RESULTS Mean ± SD humeral head version was −75.9 ± 9.6° (range, −100.7° to −59.4°). Mean mechanical lateral distal humeral angle, mechanical caudal proximal humeral angle, and mechanical cranial distal humeral angle were 89.5 ± 3.5°, 50.2 ± 4.5°, and 72.9 ± 7.8°, respectively, and did not differ from corresponding radiographic measurements. Mean humeral curvature was 20.4 ± 4.4° (range, 9.6° to 30.5°). Mean craniocaudal CFI was 1.74 ± 0.18 (range, 1.37 to 2.10). Dogs with a high craniocaudal CFI had thicker cranial and medial cortices than dogs with a low craniocaudal CFI. Increased body weight was associated with a lower craniocaudal CFI. Radiographic and CT measurements of craniocaudal CFI and curvature differed significantly.
CONCLUSIONS AND CLINICAL RELEVANCE CT-based 3-D reconstructions allowed the assessment of shaft angulation, torsion, and CFI. Radiographic and CT measurements of shaft curvature and CFI may differ.}, number={10}, journal={American Journal of Veterinary Research}, author={Smith, E. J. and Marcellin-Little, D. J. and Harrysson, Ola and Griffith, E. H.}, year={2017}, pages={1140–1149} }
 @article{mahbooba_west_harrysson_wojcieszynski_dehoff_nandwana_horn_2017, title={Effect of Hypoeutectic Boron Additions on the Grain Size and Mechanical Properties of Ti-6Al-4V Manufactured with Powder Bed Electron Beam Additive Manufacturing}, volume={69}, ISSN={["1543-1851"]}, DOI={10.1007/s11837-016-2210-9}, abstractNote={In additive manufacturing, microstructural control is feasible via processing parameter alteration. However, the window for parameter variation for certain materials, such as Ti-6Al-4V, is limited, and alternative methods must be employed to customize microstructures. Grain refinement and homogenization in cast titanium alloys has been demonstrated through the addition of hypoeutectic concentrations of boron. This work explores the influence of 0.00 wt.%, 0.25 wt.%, 0.50 wt.%, and 1.0 wt.% boron additions on the microstructure and bulk mechanical properties of Ti-6Al-4V samples fabricated in an Arcam A2 electron beam melting (EBM) system with commercial processing parameters for Ti-6Al-4V. Analyses of EBM fabricated Ti-6Al-4V + B indicate that the addition of 0.25–1.0 wt.% boron progressively refines the grain structure, and it improves hardness and elastic modulus. Despite a reduction in size, the β grain structure remained columnar as a result of directional heat transfer during EBM fabrication.}, number={3}, journal={JOM}, author={Mahbooba, Zaynab and West, Harvey and Harrysson, Ola and Wojcieszynski, Andrzej and Dehoff, Ryan and Nandwana, Peeyush and Horn, Timothy}, year={2017}, month={Mar}, pages={472–478} }
 @article{smith_marcellin-little_harrysson_griffith_2016, title={Influence of chondrodystrophy and brachycephaly on geometry of the humerus in dogs}, volume={29}, ISSN={["2567-6911"]}, DOI={10.3415/vcot-15-11-0181}, abstractNote={Summary
          Objective: To assess the geometry of canine humeri as seen on radiographs in chondrodystrophic dogs (CD) and brachycephalic dogs (BD) compared to non-chondrodystrophic dogs (NCD).
          Methods: Mediolateral (ML) and craniocaudal (CC) radiographs of skeletally mature humeri were used (CD [n = 5], BD [n = 9], NCD [n = 48]) to evaluate general dimensions (length, width, canal flare, cortical thickness), curvature (shaft, humeral head, and glenoid), and angulation (humeral head and condyle). Measurements from CD, BD, and NCD were compared.
          Results: Mean humeral length was shorter in CD (108 mm) compared to BD (184 mm, p = 0.001) and NCD (183 mm, p <0.001). Craniocaudal cortical thickness at 70% of humeral length and ML cortical thickness at 30%, 50%, and 70% of humeral length were less in CD compared to BD and NCD. Humeral shaft curvature was greater in CD (9.9°) compared to BD (6.7°, p = 0.023). The ratio of glenoid radius of curvature / humeral length was greater for CD (11.1%) compared to NCD (9.7%, p = 0.013). The ratio of humeral width / humeral length was greater for BD (29.4%) compared to NCD (26.2%, p = 0.043). The ratio of glenoid length / humeral length was greater in CD (18.0%) than BD (16.4%, p = 0.048) and NCD (15.6%, p <0.001).
          Clinical significance: Bone proportions and curvature in CD differ from BD and NCD. Differences are minor and unlikely to have clinical significance.}, number={3}, journal={VETERINARY AND COMPARATIVE ORTHOPAEDICS AND TRAUMATOLOGY}, author={Smith, Emily J. and Marcellin-Little, Denis J. and Harrysson, Ola L. A. and Griffith, Emily H.}, year={2016}, pages={220–226} }
 @article{seifi_salem_beuth_harrysson_lewandowski_2016, title={Overview of Materials Qualification Needs for Metal Additive Manufacturing}, volume={68}, ISSN={["1543-1851"]}, DOI={10.1007/s11837-015-1810-0}, abstractNote={This overview highlights some of the key aspects regarding materials qualification needs across the additive manufacturing (AM) spectrum. AM technology has experienced considerable publicity and growth in the past few years with many successful insertions for non-mission-critical applications. However, to meet the full potential that AM has to offer, especially for flight-critical components (e.g., rotating parts, fracture-critical parts, etc.), qualification and certification efforts are necessary. While development of qualification standards will address some of these needs, this overview outlines some of the other key areas that will need to be considered in the qualification path, including various process-, microstructure-, and fracture-modeling activities in addition to integrating these with lifing activities targeting specific components. Ongoing work in the Advanced Manufacturing and Mechanical Reliability Center at Case Western Reserve University is focusing on fracture and fatigue testing to rapidly assess critical mechanical properties of some titanium alloys before and after post-processing, in addition to conducting nondestructive testing/evaluation using micro-computerized tomography at General Electric. Process mapping studies are being conducted at Carnegie Mellon University while large area microstructure characterization and informatics (EBSD and BSE) analyses are being conducted at Materials Resources LLC to enable future integration of these efforts via an Integrated Computational Materials Engineering approach to AM. Possible future pathways for materials qualification are provided.}, number={3}, journal={JOM}, author={Seifi, Mohsen and Salem, Ayman and Beuth, Jack and Harrysson, Ola and Lewandowski, John J.}, year={2016}, month={Mar}, pages={747–764} }
 @article{seifi_salem_beuth_harrysson_lewandowski_2016, title={Overview of Materials Qualification Needs for Metal Additive Manufacturing (vol 68, pg 747, 2016)}, volume={68}, ISSN={["1543-1851"]}, DOI={10.1007/s11837-016-1901-6}, number={5}, journal={JOM}, author={Seifi, Mohsen and Salem, Ayman and Beuth, Jack and Harrysson, Ola and Lewandowski, John J.}, year={2016}, month={May}, pages={1492–1492} }
 @inproceedings{shouche_wysk_king_harrysson_2016, title={Supply chain operations reference model for us based powder bed metal additive manufacturing processes}, DOI={10.1109/wsc.2016.7822173}, abstractNote={This paper focuses on modeling the supply chain of an additively manufactured, uniquely customized Total Hip Replacement implant. It explores how the supply chain could be modeled for hip components which are customized for individual patients and produced using additive manufacturing processes. The concept of the SCOR (Supply Chain Operations Reference) model is used to create a formal model of this system. The SCOR model is used to compare the traditional and the AM supply chain on the basis of different performance metrics. The formal supply chain model is used to extract operational activities so that a computer simulation model of the system can be developed. The simulation is used to model system performance so that bottleneck operations can be identified and source needs determined along with a sensitivity analysis to analyze how change in times and resources affect production quantities.}, booktitle={2016 winter simulation conference (wsc)}, author={Shouche, S. and Wysk, R. A. and King, Russell and Harrysson, Ola}, year={2016}, pages={1158–1169} }
 @article{algardh_horn_west_aman_snis_engqvist_lausmaa_harrysson_2016, title={Thickness dependency of mechanical properties for thin-walled titanium parts manufactured by Electron Beam Melting (EBM) ®}, volume={12}, ISSN={2214-8604}, url={http://dx.doi.org/10.1016/J.ADDMA.2016.06.009}, DOI={10.1016/J.ADDMA.2016.06.009}, abstractNote={Metal powder bed additive manufacturing technologies, such as the Electron Beam Melting process, facilitate a high degree of geometric flexibility and have been demonstrated as useful production techniques for metallic parts. However, the EBM process is typically associated with lower resolutions and higher surface roughness compared to similar laser-based powder bed metal processes. In part, this difference is related to the larger powder size distribution and thicker layers normally used. As part of an effort to improve the resolution and surface roughness of EBM fabricated components, this study investigates the feasibility of fabricating components with a smaller powder size fraction and layer thickness (similar to laser based processes). The surface morphology, microstructure and tensile properties of the produced samples were evaluated. The findings indicate that microstructure is dependent on wall-thickness and that, for thin walled structures, tensile properties can become dominated by variations in surface roughness.}, journal={Additive Manufacturing}, publisher={Elsevier BV}, author={Algardh, Joakim Karlsson and Horn, Timothy and West, Harvey and Aman, Ronald and Snis, Anders and Engqvist, Håkan and Lausmaa, Jukka and Harrysson, Ola}, year={2016}, month={Oct}, pages={45–50} }
 @article{manogharan_wysk_harrysson_aman_2015, title={AIMS – A Metal Additive-hybrid Manufacturing System: System Architecture and Attributes}, volume={1}, ISSN={2351-9789}, url={http://dx.doi.org/10.1016/J.PROMFG.2015.09.021}, DOI={10.1016/J.PROMFG.2015.09.021}, abstractNote={This paper presents an integrated hybrid manufacturing approach to enhance and accelerate the adoption of metal Additive Manufacturing (AM) by adding a direct digital subtractive process to the production that is capable of improving the form, location and position tolerance of critical part features as well as improving surface finish. The hybrid system, AIMS (Additive systems Integrated with subtractive MethodS) can be integrated with existing metal AM systems without any significant modifications. The intent of this paper is to: 1) detail the system architecture, 2) highlight the process requirements, and 3) illustrate the sequential functions from development of CAD models through AM processing, to subtractive post-processing and corresponding process monitoring. Attributes of individual components such as physical and computational requirements associated with each discrete step of the overall process is presented. Advantages and current limitations of AIMS are also noted. The developed models provide insight into how the overall process-flow could be affected by errors (variability) due to both physical and data transfer across multiple systems. This paper also presents a generalized use of AIMS-for a variety of part geometries, noting materials and processing efficiencies associated with this unique hybrid method.}, journal={Procedia Manufacturing}, publisher={Elsevier BV}, author={Manogharan, Guha and Wysk, Richard and Harrysson, Ola and Aman, Ronald}, year={2015}, pages={273–286} }
 @inproceedings{manogharan_wysk_harrysson_aman_2015, title={AIMS- a metal additive-hybrid manufacturing system: System architecture and attributes}, volume={43}, booktitle={43rd North American Manufacturing Research Conference, NAMRC}, author={Manogharan, G. and Wysk, R. and Harrysson, O. and Aman, R.}, year={2015}, pages={273–286} }
 @article{yang_harrysson_cormier_west_gong_stucker_2015, title={Additive Manufacturing of Metal Cellular Structures: Design and Fabrication}, volume={67}, ISSN={["1543-1851"]}, DOI={10.1007/s11837-015-1322-y}, number={3}, journal={JOM}, author={Yang, Li and Harrysson, Ola and Cormier, Denis and West, Harvey and Gong, Haijun and Stucker, Brent}, year={2015}, month={Mar}, pages={608–615} }
 @article{manogharan_wysk_harrysson_2016, title={Additive manufacturing-integrated hybrid manufacturing and subtractive processes: economic model and analysis}, volume={29}, ISSN={["1362-3052"]}, DOI={10.1080/0951192x.2015.1067920}, abstractNote={This article presents economic models for a new hybrid method where additive manufacturing (AM) and subtractive methods (SMs) are integrated through composite process planning. Although AM and SM offer several unique advantages, there are technological limitations such as tolerance and surface finish requirements; tooling and fixturing, etc. that cannot be met by a single type of manufacturing. The intent of this article is not to show a new manufacturing method, but rather to provide economic context to additive and subtractive methods as the best practice provides, and look at the corresponding economics of each of those methods as a function of production batch size, machinability, cost of the material, part geometry and tolerance requirements. Basic models of fixed and variable costs associated with additive, subtractive and hybrid methods to produce parts are also presented. An experimental design is used to study the influence of production volume, material and operating cost, batch size, machinability of the material and impact of reducing AM processing time. A composite response model for the unit cost is computed for the various levels associated with such engineering requirements. The developed models provide insight into how these variables affect the costs associated with engineering a mechanical product that will be produced using AM and SM methods. From the results, it appears that batch size, AM processing time and AM processing cost were the major cost factors. It was shown that the cost of producing ‘near-net’ shape through SM and AM was the decision criteria; which will be critical for tough-to-machine alloys and at multi-batch size.}, number={5}, journal={INTERNATIONAL JOURNAL OF COMPUTER INTEGRATED MANUFACTURING}, author={Manogharan, Guha and Wysk, Richard A. and Harrysson, Ola L. A.}, year={2016}, month={May}, pages={473–488} }
 @article{harrysson_marcellin-little_horn_2015, title={Applications of Metal Additive Manufacturing in Veterinary Orthopedic Surgery}, volume={67}, ISSN={["1543-1851"]}, DOI={10.1007/s11837-015-1295-x}, number={3}, journal={JOM}, author={Harrysson, Ola L. A. and Marcellin-Little, Denis J. and Horn, Timothy J.}, year={2015}, month={Mar}, pages={647–654} }
 @article{srinivasan_harrysson_wysk_2015, title={Automatic part localization in a CNC machine coordinate system by means of 3D scans}, volume={81}, ISSN={["1433-3015"]}, DOI={10.1007/s00170-015-7178-z}, number={5-8}, journal={INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY}, author={Srinivasan, Harshad and Harrysson, Ola L. A. and Wysk, Richard A.}, year={2015}, month={Nov}, pages={1127–1138} }
 @article{seifi_dahar_aman_harrysson_beuth_lewandowski_2015, title={Evaluation of Orientation Dependence of Fracture Toughness and Fatigue Crack Propagation Behavior of As-Deposited ARCAM EBM Ti-6Al-4V}, volume={67}, ISSN={["1543-1851"]}, DOI={10.1007/s11837-015-1298-7}, number={3}, journal={JOM}, author={Seifi, Mohsen and Dahar, Matthew and Aman, Ron and Harrysson, Ola and Beuth, Jack and Lewandowski, John J.}, year={2015}, month={Mar}, pages={597–607} }
 @article{yang_harrysson_west_cormier_park_peters_2015, title={Low-energy drop weight performance of cellular sandwich panels}, volume={21}, ISSN={["1758-7670"]}, DOI={10.1108/rpj-08-2013-0083}, abstractNote={
               Purpose
                – The aim of this study is to perform a comparative study on sandwich structures with several types of three-dimensional (3D) reticulate cellular structural core designs for their low-energy impact absorption abilities using powder bed additive manufacturing methods. 3D reticulate cellular structures possess promising potentials in various applications with sandwich structure designs. One of the properties critical to the sandwich structures in applications, such as aerospace and automobile components, is the low-energy impact performance. 
            
            
               Design/methodology/approach
                – Sandwich samples of various designs, including re-entrant auxetic, rhombic, hexagonal and octahedral, were designed and fabricated via selective laser sintering (SLS) process using nylon 12 as material. Low-energy drop weight test was performed to evaluate the energy absorption of various designs. Tensile coupons were also produced using the same process to provide baseline material properties. The manufacturing issues such as geometrical accuracy and anisotropy effect as well as their effects on the performance of the structures were discussed. 
            
            
               Findings
                – In general, 3D reticulate cellular structures made by SLS process exhibit significantly different characteristics under low-energy drop weight impact compared to the regular extruded honeycomb sandwich panels. A hexagonal sandwich panel exhibits the largest compliance with the smallest energy absorption ability, and an octahedral sandwich panel exhibits high stiffness as well as good impact protection ability. Through a proper geometrical design, the re-entrant auxetic sandwich panels could achieve a combination of high energy absorption and low response force, making it especially attractive for low-impact protection applications. 
            
            
               Originality/value
                – There has been little work on the comparative study of the energy absorption of various 3D reticulate cellular structures to date. This work demonstrates the potential of 3D reticulate cellular structures as sandwich cores for different purposes. This work also demonstrates the possibility of controlling the performance of this type of sandwich structures via geometrical and process design of the cellular cores with powder bed additive manufacturing systems.
            }, number={4}, journal={RAPID PROTOTYPING JOURNAL}, author={Yang, Li and Harrysson, Ola A. and West, Harvey A., II and Cormier, Denis R. and Park, Chun and Peters, Kara}, year={2015}, pages={433–442} }
 @article{hunsberger_harrysson_shirwaiker_starly_wysk_cohen_allickson_yoo_atala_2015, title={Manufacturing Road Map for Tissue Engineering and Regenerative Medicine Technologies}, volume={4}, ISSN={["2157-6580"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84921807245&partnerID=MN8TOARS}, DOI={10.5966/sctm.2014-0254}, abstractNote={Abstract
               
                  Summary
                  The Regenerative Medicine Foundation Annual Conference held on May 6 and 7, 2014, had a vision of assisting with translating tissue engineering and regenerative medicine (TERM)-based technologies closer to the clinic. This vision was achieved by assembling leaders in the field to cover critical areas. Some of these critical areas included regulatory pathways for regenerative medicine therapies, strategic partnerships, coordination of resources, developing standards for the field, government support, priorities for industry, biobanking, and new technologies. The final day of this conference featured focused sessions on manufacturing, during which expert speakers were invited from industry, government, and academia. The speakers identified and accessed roadblocks plaguing the field where improvements in advanced manufacturing offered many solutions. The manufacturing sessions included (a) product development toward commercialization in regenerative medicine, (b) process challenges to scale up manufacturing in regenerative medicine, and (c) infrastructure needs for manufacturing in regenerative medicine. Subsequent to this, industry was invited to participate in a survey to further elucidate the challenges to translation and scale-up. This perspective article will cover the lessons learned from these manufacturing sessions and early results from the survey. We also outline a road map for developing the manufacturing infrastructure, resources, standards, capabilities, education, training, and workforce development to realize the promise of TERM.
               }, number={2}, journal={STEM CELLS TRANSLATIONAL MEDICINE}, author={Hunsberger, Joshua and Harrysson, Ola and Shirwaiker, Ronan and Starly, Binil and Wysk, Richard and Cohen, Paul and Allickson, Julie and Yoo, James and Atala, Anthony}, year={2015}, month={Feb}, pages={130–135} }
 @article{yang_harrysson_west_cormier_2015, title={Mechanical properties of 3D re-entrant honeycomb auxetic structures realized via additive manufacturing}, volume={69-70}, ISSN={["1879-2146"]}, DOI={10.1016/j.ijsolstr.2015.05.005}, abstractNote={In this work, an analytical model of a 3D re-entrant honeycomb auxetic cellular structure has been established based on both a large deflection beam model and a Timoshenko beam model. Analytical solutions for the modulus, Poisson’s ratios and yield strength of the cellular structure in all principal directions were obtained, which indicate a wide range of mechanical property control via geometrical designs. The results were compared with experimentation and finite element analysis, and it was verified that the analytical model provides a convenient and relatively accurate method in the prediction of the performance for the auxetic cellular structures once the manufacturing related factors are adequately incorporated into the model. It was also found that the model provides less accurate predictions when higher-order coupling effects such as warp locking becomes significant under lower structural symmetry.}, journal={INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES}, author={Yang, Li and Harrysson, Ola and West, Harvey and Cormier, Denis}, year={2015}, month={Sep}, pages={475–490} }
 @article{rose_kimbell_webster_harrysson_formeister_buchman_2015, title={Multi-material 3D Models for Temporal Bone Surgical Simulation}, volume={124}, ISSN={["1943-572X"]}, DOI={10.1177/0003489415570937}, abstractNote={Hypothesis: A simulated, multicolor, multi-material temporal bone model can be created using 3-dimensional (3D) printing that will prove both safe and beneficial in training for actual temporal bone surgical cases. Background: As the process of additive manufacturing, or 3D printing, has become more practical and affordable, a number of applications for the technology in the field of Otolaryngology–Head and Neck Surgery have been considered. One area of promise is temporal bone surgical simulation. Methods: Three-dimensional representations of human temporal bones were created from temporal bone computed tomography (CT) scans using biomedical image processing software. Multi-material models were then printed and dissected in a temporal bone laboratory by attending and resident otolaryngologists. A 5-point Likert scale was used to grade the models for their anatomical accuracy and suitability as a simulation of cadaveric and operative temporal bone drilling. Results: The models produced for this study demonstrate significant anatomic detail and a likeness to human cadaver specimens for drilling and dissection. Conclusion: Simulated temporal bones created by this process have potential benefit in surgical training, preoperative simulation for challenging otologic cases, and the standardized testing of temporal bone surgical skills. }, number={7}, journal={ANNALS OF OTOLOGY RHINOLOGY AND LARYNGOLOGY}, author={Rose, Austin S. and Kimbell, Julia S. and Webster, Caroline E. and Harrysson, Ola L. A. and Formeister, Eric J. and Buchman, Craig A.}, year={2015}, month={Jul}, pages={528–536} }
 @article{west_harrysson_horn_cormier_aman_marcellin-little_2015, title={Novel Materials and Structures Fabricated by Electron Beam Melting}, volume={21}, ISSN={1431-9276 1435-8115}, url={http://dx.doi.org/10.1017/S1431927615003104}, DOI={10.1017/S1431927615003104}, abstractNote={Researchers in the Center for Additive Manufacturing and Logistics (CAMAL) in the Edward P. Fitts Department of Industrial and Systems Engineering at North Carolina State University have been active in the area of additive manufacturing since 2000, and have gained an international reputation for their research and educational efforts. While, historically, the first rapid prototyping machines were created to produce parts from thermoset or thermoplastic polymers, the additive manufacturing of metal components has become the most important research topic for a wide variety of industries including aerospace, medicine, power industry, and the military. NCSU was the first user of Electron Beam Melting (EBM) technology in the world when, in 2003, the world’s first EBM machine was acquired from Arcam AB (Mölndal, Sweden). This technology allows for production of fully dense metal parts using an electron beam to selectively fuse layers of metal powder.}, number={S3}, journal={Microscopy and Microanalysis}, publisher={Cambridge University Press (CUP)}, author={West, Harvey and Harrysson, Ola and Horn, Tim and Cormier, Denis and Aman, Ron and Marcellin-Little, Denis}, year={2015}, month={Aug}, pages={461–462} }
 @article{hasib_harrysson_west_2015, title={Powder Removal from Ti-6Al-4V Cellular Structures Fabricated via Electron Beam Melting}, volume={67}, ISSN={["1543-1851"]}, DOI={10.1007/s11837-015-1307-x}, abstractNote={Direct metal fabrication systems like electron beam melting (EBM) and direct metal laser sintering (also called selective laser melting) are gaining popularity. One reason is the design and fabrication freedom that these technologies offer over traditional processes. One specific feature that is of interest is mesh or lattice structures that can be produced using these powder-bed systems. One issue with the EBM process is that the powder trapped within the structure during the fabrication process is sintered and can be hard to remove as the mesh density increases. This is usually not an issue for the laser-based systems since most of them work at a low temperature and the sintering of the powder is less of an issue. Within the scope of this project, a chemical etching process was evaluated for sintered powder removal using three different cellular structures with varying mesh densities. All meshes were fabricated via EBM using Ti6Al4V powder. The results are promising, but the larger the structures, the more difficult it is to completely remove the sintered powder without affecting the integrity of the mesh structure.}, number={3}, journal={JOM}, author={Hasib, Hazman and Harrysson, Ola L. A. and West, Harvey A., II}, year={2015}, month={Mar}, pages={639–646} }
 @article{rose_webster_harrysson_formeister_rawal_iseli_2015, title={Pre-operative simulation of pediatric mastoid surgery with 3D-printed temporal bone models}, volume={79}, ISSN={["1872-8464"]}, DOI={10.1016/j.ijporl.2015.03.004}, abstractNote={As the process of additive manufacturing, or three-dimensional (3D) printing, has become more practical and affordable, a number of applications for the technology in the field of pediatric otolaryngology have been considered. One area of promise is temporal bone surgical simulation. Having previously developed a model for temporal bone surgical training using 3D printing, we sought to produce a patient-specific model for pre-operative simulation in pediatric otologic surgery. Our hypothesis was that the creation and pre-operative dissection of such a model was possible, and would demonstrate potential benefits in cases of abnormal temporal bone anatomy. In the case presented, an 11-year-old boy underwent a planned canal-wall-down (CWD) tympano-mastoidectomy for recurrent cholesteatoma preceded by a pre-operative surgical simulation using 3D-printed models of the temporal bone. The models were based on the child's pre-operative clinical CT scan and printed using multiple materials to simulate both bone and soft tissue structures. To help confirm the models as accurate representations of the child's anatomy, distances between various anatomic landmarks were measured and compared to the temporal bone CT scan and the 3D model. The simulation allowed the surgical team to appreciate the child's unusual temporal bone anatomy as well as any challenges that might arise in the safety of the temporal bone laboratory, prior to actual surgery in the operating room (OR). There was minimal variability, in terms of absolute distance (mm) and relative distance (%), in measurements between anatomic landmarks obtained from the patient intra-operatively, the pre-operative CT scan and the 3D-printed models. Accurate 3D temporal bone models can be rapidly produced based on clinical CT scans for pre-operative simulation of specific challenging otologic cases in children, potentially reducing medical errors and improving patient safety.}, number={5}, journal={INTERNATIONAL JOURNAL OF PEDIATRIC OTORHINOLARYNGOLOGY}, author={Rose, Austin S. and Webster, Caroline E. and Harrysson, Ola L. A. and Formeister, Eric J. and Rawal, Rounak B. and Iseli, Claire E.}, year={2015}, month={May}, pages={740–744} }
 @inproceedings{huang_huang_gettys_prim_harrysson_2014, title={A biomechanical study of directional mechanical properties of porcine skin tissues}, booktitle={Proceedings of the ASME International Mechanical Engineering Congress and Exposition, 2013, vol 9}, author={Huang, H. Y. S. and Huang, S. Y. and Gettys, T. and Prim, P. M. and Harrysson, O. L.}, year={2014} }
 @article{horn_harrysson_west_little_marcellin-little_2014, title={Development of a patient-specific bone analog for the biomechanical evaluation of custom implants}, volume={20}, ISSN={["1758-7670"]}, DOI={10.1108/rpj-08-2012-0069}, abstractNote={
               Purpose
                – The aim of this study is to describe an improved experimental substrate for the mechanical testing of patient-specific implants fabricated using direct metal additive manufacturing processes. This method reduces variability and sample size requirements and addresses the importance of geometry at the bone/implant interface. 
            
            
               Design/methodology/approach
                – Short-fiber glass/resin materials for cortical bone and polyurethane foam materials for cancellous bone were evaluated using standard tensile coupons. A method for fabricating bone analogs with patient-specific geometries using rapid tooling is presented. Bone analogs of a canine radius were fabricated and compared to cadaveric specimens in several biomechanical tests as validation. 
            
            
               Findings
                – The analog materials exhibit a tensile modulus that falls within the range of expected values for cortical and cancellous bone. The tensile properties of the cortical bone analog vary with fiber loading. The canine radius models exhibited similar mechanical properties to the cadaveric specimens with a reduced variability. 
            
            
               Research limitations/implications
                – Additional replications involving different bone geometries, types of bone and/or implants are required for a full validation. Further, the materials used here are only intended to mimic the mechanical properties of bone on a macro scale within a relatively narrow range. These analog models have not been shown to address the complex microscopic or viscoelastic behavior of bone in the present study. 
            
            
               Originality/value
                – Scientific data on the formulation and fabrication of bone analogs are absent from the literature. The literature also lacks an experimental platform that matches patient-specific implant/bone geometries at the bone implant interface.
            }, number={1}, journal={RAPID PROTOTYPING JOURNAL}, author={Horn, Timothy J. and Harrysson, Ola L. A. and West, Harvey A., II and Little, Jeffrey P. and Marcellin-Little, Denis J.}, year={2014}, pages={41–49} }
 @article{huang_huang_frazier_prim_harrysson_2014, title={Directional biomechanical properties of porcine skin tissue}, volume={14}, number={5}, journal={Journal of Mechanics in Medicine and Biology}, author={Huang, H. Y. S. and Huang, S. Y. and Frazier, C. P. and Prim, P. M. and Harrysson, O.}, year={2014} }
 @article{frigola_harrysson_horn_west_aman_rigsbee_ramirez_murr_medina_wicker_et al._2014, title={Fabricating copper components with electron beam melting}, volume={172}, number={7}, journal={Advanced Materials & Processes}, author={Frigola, P. and Harrysson, O. A. and Horn, T. J. and West, H. A. and Aman, R. L. and Rigsbee, J. M. and Ramirez, D. A. and Murr, L. E. and Medina, F. and Wicker, R. B. and et al.}, year={2014}, pages={20–24} }
 @article{horn_harrysson_marcellin-little_west_lascelles_aman_2014, title={Flexural properties of Ti6Al4V rhombic dodecahedron open cellular structures fabricated with electron beam melting}, volume={1-4}, ISSN={2214-8604}, url={http://dx.doi.org/10.1016/J.ADDMA.2014.05.001}, DOI={10.1016/J.ADDMA.2014.05.001}, abstractNote={Open cellular structures fabricated in Ti6Al4V using the electron beam melting (EBM) process have been proposed for tissue scaffolds and low stiffness implants that approximate the properties of bone. The properties of these structures, regardless of cell geometry, have often been determined through compressive testing, and very few of these studies have investigated the flexural properties. For certain types of implants that are designed to fill very large segmental defects in appendicular bones, such as those used in limb sparing, compression testing does not provide the necessary insight into the complex loading states typical of bending. In this study, EBM-fabricated Ti6Al4V prismatic bars, populated with rhombic dodecahedron unit cells of various sizes and relative densities, were subjected to four-point flexure tests. While the results generally follow the power scaling models of Gibson and Ashby, the use of these models as a design tool is limited by machine resolution, particularly when producing structures with small pore sizes required for bone ingrowth.}, journal={Additive Manufacturing}, publisher={Elsevier BV}, author={Horn, Timothy J. and Harrysson, Ola L.A. and Marcellin-Little, Denis J. and West, Harvey A. and Lascelles, B. Duncan X. and Aman, Ronald}, year={2014}, month={Oct}, pages={2–11} }
 @article{springer_harrysson_marcellin-little_bernacki_2014, title={In vitro dermal and epidermal cellular response to titanium alloy implants fabricated with electron beam melting}, volume={36}, ISSN={["1873-4030"]}, DOI={10.1016/j.medengphy.2014.07.004}, abstractNote={Transdermal osseointegrated prostheses (TOPs) are emerging as an alternative to socket prostheses. Electron beam melting (EBM) is a promising additive manufacturing technology for manufacture of custom, freeform titanium alloy (Ti6Al4V) implants. Skin ongrowth for infection resistance and mechanical stability are critically important to the success of TOP, which can be influenced by material composition and surface characteristics. We assessed viability and proliferation of normal human epidermal keratinocytes (NHEK) and normal human dermal fibroblasts (NHDF) on several Ti6Al4V surfaces: solid polished commercial, solid polished EBM, solid unpolished EBM and porous unpolished EBM. Cell proliferation was evaluated at days 2 and 7 using alamarBlue(®) and cell viability was analyzed with a fluorescence-based live-dead assay after 1 week. NHDF and NHEK were viable and proliferated on all Ti6Al4V surfaces. NHDF proliferation was highest on commercial and EBM polished surfaces. NHEK was highest on commercial polished surfaces. All EBM Ti6Al4V discs exhibited an acceptable biocompatibility profile compared to solid Ti6Al4V discs from a commercial source for dermal and epidermal cells. EBM may be considered as an option for fabrication of custom transdermal implants.}, number={10}, journal={MEDICAL ENGINEERING & PHYSICS}, author={Springer, Jessica Collins and Harrysson, Ola L. A. and Marcellin-Little, Denis J. and Bernacki, Susan H.}, year={2014}, month={Oct}, pages={1367–1372} }
 @inproceedings{huang_huang_gettys_harrysson_2013, title={A biomechanical study of directional mechanical properties of porcine skin tissues}, booktitle={ASME 2013 International Mechanical Engineering Congress & Exposition}, author={Huang, H.-Y. S. and Huang, S. and Gettys, T. A. and Harrysson, O.}, year={2013} }
 @article{gulledge_marcellin-little_levine_tillman_harrysson_osborne_baxter_2014, title={Comparison of two stretching methods and optimization of stretching protocol for the piriformis muscle}, volume={36}, ISSN={1350-4533}, url={http://dx.doi.org/10.1016/J.MEDENGPHY.2013.10.016}, DOI={10.1016/j.medengphy.2013.10.016}, abstractNote={Piriformis syndrome is an uncommon diagnosis for a non-discogenic form of sciatica whose treatment has traditionally focused on stretching the piriformis muscle (PiM). Conventional stretches include hip flexion, adduction, and external rotation. Using three-dimensional modeling, we quantified the amount of (PiM) elongation resulting from two conventional stretches and we investigated by use of a computational model alternate stretching protocols that would optimize PiM stretching. Seven subjects underwent three CT scans: one supine, one with hip flexion, adduction, then external rotation (ADD stretch), and one with hip flexion, external rotation, then adduction (ExR stretch). Three-dimensional bone models were constructed from the CT scans. PiM elongation during these stretches, femoral neck inclination, femoral head anteversion, and trochanteric anteversion were measured. A computer program was developed to map PiM length over a range of hip joint positions and was validated against the measured scans. ExR and ADD stretches elongated the PiM similarly by approximately 12%. Femoral head and greater trochanter anteversion influenced PiM elongation. Placing the hip joints in 115° of hip flexion, 40° of external rotation and 25° of adduction or 120° of hip flexion, 50° of external rotation and 30° of adduction increased PiM elongation by 30–40% compared to conventional stretches (15.1 and 15.3% increases in PiM muscle length, respectively). ExR and ADD stretches elongate the PiM similarly and therefore may have similar clinical effectiveness. The optimized stretches led to larger increases in PiM length and may be more easily performed by some patients due to increased hip flexion.}, number={2}, journal={Medical Engineering & Physics}, publisher={Elsevier BV}, author={Gulledge, Brett M. and Marcellin-Little, Denis J. and Levine, David and Tillman, Larry and Harrysson, Ola L.A. and Osborne, Jason A. and Baxter, Blaise}, year={2014}, month={Feb}, pages={212–218} }
 @article{yang_harrysson_west_cormier_2012, title={Compressive properties of Ti-6Al-4V auxetic mesh structures made by electron beam melting}, volume={60}, ISSN={["1873-2453"]}, DOI={10.1016/j.actamat.2012.03.015}, abstractNote={In this current work, a Ti–6Al–4V 3-D re-entrant lattice auxetic structure is manufactured by the electron beam melting (EBM) process. Four different design configurations (two negative Poisson’s ratio values × two relative densities) were manufactured and tested under compressive stress. Two failure modes were observed whose occurrence appeared to be dependent on the ratio of vertical strut length to re-entrant strut length. A small deflection analytical model is presented that predicts yield strength and modulus for one type of design with good accuracy. Results also show that the re-entrant lattice structure possesses superior mechanical properties compared to regular foam structures. Limitations of the analytical model are also discussed.}, number={8}, journal={ACTA MATERIALIA}, author={Yang, Li and Harrysson, Ola and West, Harvey and Cormier, Denis}, year={2012}, month={May}, pages={3370–3379} }
 @article{kumar_cormier_harrysson_2012, title={Electrical conductivity of hexagonal periodic lattice structures}, volume={7}, ISSN={1745-2759 1745-2767}, url={http://dx.doi.org/10.1080/17452759.2012.668784}, DOI={10.1080/17452759.2012.668784}, abstractNote={Periodic lattice structures are three-dimensional arrays of unit cells having carefully engineered geometric properties. Solid Freeform Fabrication (SFF) processes have made it possible to tailor structural, thermal, or electrical properties by varying the shape and density of the unit-cell geometry. In this paper, the electrical conductivity of a hexagonal lattice structure is analytically derived using an effective unit-cell approach. The relationship between ligament length, ligament radius, relative density and electrical conductivity has been derived. The analysis indicates that the electrical conductivity increases with relative density and is linearly dependent on relative density at low lattice densities. Conductivity measurements of Ti-6Al-4V hexagonal lattices made via the Electron Beam Melting (EBM) process over a range of relative densities from 4% to 16% were taken in order to experimentally validate the analytical models.}, number={1}, journal={Virtual and Physical Prototyping}, publisher={Informa UK Limited}, author={Kumar, Vikas and Cormier, Denis and Harrysson, Ola}, year={2012}, month={Mar}, pages={81–90} }
 @article{yang_harrysson_west_cormier_2013, title={Modeling of uniaxial compression in a 3D periodic re-entrant lattice structure}, volume={48}, ISSN={["0022-2461"]}, DOI={10.1007/s10853-012-6892-2}, number={4}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Yang, Li and Harrysson, Ola and West, Harvey and Cormier, Denis}, year={2013}, month={Feb}, pages={1413–1422} }
 @article{yang_cormier_west_harrysson_knowlson_2012, title={Non-stochastic Ti-6Al-4V foam structures with negative Poisson's ratio}, volume={558}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2012.08.053}, abstractNote={This paper details the design, fabrication, and testing of non-stochastic auxetic lattice lattice structures. All Ti–6Al–4V samples were created via the Electron Beam Melting (EBM) additive manufacturing process. It was found that the Poisson's ratio values significantly influence the mechanical properties of the structures. The bending properties of the auxetic samples were significantly higher than those of currently commercialized metal foams. The compressive strength was moderately higher than available metal foams. These results suggest that metallic auxetic structures have considerable promise for use in a variety of applications in which tradeoffs between mass and mechanical properties are crucial.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Yang, Li and Cormier, Denis and West, Harvey and Harrysson, Ola and Knowlson, Kyle}, year={2012}, month={Dec}, pages={579–585} }
 @article{little_horn_marcellin-little_harrysson_west_2012, title={Development and validation of a canine radius replica for mechanical testing of orthopedic implants}, volume={73}, ISSN={["1943-5681"]}, DOI={10.2460/ajvr.73.1.27}, abstractNote={Abstract
Objective—To design and fabricate fiberglass-reinforced composite (FRC) replicas of a canine radius and compare their mechanical properties with those of radii from dog cadavers.
Sample—Replicas based on 3 FRC formulations with 33%, 50%, or 60% short-length discontinuous fiberglass by weight (7 replicas/group) and 5 radii from large (> 30-kg) dog cadavers.
Procedures—Bones and FRC replicas underwent nondestructive mechanical testing including 4-point bending, axial loading, and torsion and destructive testing to failure during 4-point bending. Axial, internal and external torsional, and bending stiffnesses were calculated. Axial pullout loads for bone screws placed in the replicas and cadaveric radii were also assessed.
Results—Axial, internal and external torsional, and 4-point bending stiffnesses of FRC replicas increased significantly with increasing fiberglass content. The 4-point bending stiffness of 33% and 50% FRC replicas and axial and internal torsional stiffnesses of 33% FRC replicas were equivalent to the cadaveric bone stiffnesses. Ultimate 4-point bending loads did not differ significantly between FRC replicas and bones. Ultimate screw pullout loads did not differ significantly between 33% or 50% FRC replicas and bones. Mechanical property variability (coefficient of variation) of cadaveric radii was approximately 2 to 19 times that of FRC replicas, depending on loading protocols.
Conclusions and Clinical Relevance—Within the range of properties tested, FRC replicas had mechanical properties equivalent to and mechanical property variability less than those of radii from dog cadavers. Results indicated that FRC replicas may be a useful alternative to cadaveric bones for biomechanical testing of canine bone constructs.}, number={1}, journal={AMERICAN JOURNAL OF VETERINARY RESEARCH}, author={Little, Jeffrey P. and Horn, Timothy J. and Marcellin-Little, Denis J. and Harrysson, Ola L. A. and West, Harvey A., II}, year={2012}, month={Jan}, pages={27–33} }
 @article{fitzwater_marcellin-little_harrysson_osborne_poindexter_2011, title={Evaluation of the effect of computed tomography scan protocols and freeform fabrication methods on bone biomodel accuracy}, volume={72}, ISSN={["1943-5681"]}, DOI={10.2460/ajvr.72.9.1178}, abstractNote={Abstract
Objective—To assess the effect of computed tomography (CT) scan protocols (radiation amounts) and fabrication methods on biomodel accuracy and variability.
Sample—Cadaveric femur of a Basset Hound.
Procedures—Retroreconstructions (n = 158) were performed of 16 original scans and were visually inspected to select 17 scans to be used for biomodel fabrication. Biomodels of the 17 scans were made in triplicate by use of 3 freeform fabrication processes (stereolithography, fused deposition modeling, and 3-D printing) for 153 models. The biomodels and original bone were measured by use of a coordinate measurement machine.
Results—Differences among fabrication methods accounted for 2% to 29% of the total observed variation in inaccuracy and differences among method-specific radiation configurations accounted for 4% to 44%. Biomodels underestimated bone length and width and femoral head diameter and overestimated cortical thickness. There was no evidence of a linear association between thresholding adjustments and biomodel accuracy. Higher measured radiation dose led to a decrease in absolute relative error for biomodel diameter and for 4 of 8 cortical thickness measurements.
Conclusions and Clinical Relevance—The outside dimensions of biomodels have a clinically acceptable accuracy. The cortical thickness of biomodels may overestimate cortical thickness. Variability among biomodels was caused by model fabrication reproducibility and, to a lesser extent, by the radiation settings of the CT scan and differences among fabrication methods.}, number={9}, journal={AMERICAN JOURNAL OF VETERINARY RESEARCH}, author={Fitzwater, Kathryn L. and Marcellin-Little, Denis J. and Harrysson, Ola L. A. and Osborne, Jason A. and Poindexter, E. Christine}, year={2011}, month={Sep}, pages={1178–1185} }
 @article{haslauer_springer_harrysson_loboa_monteiro-riviere_marcellin-little_2010, title={In vitro biocompatibility of titanium alloy discs made using direct metal fabrication}, volume={32}, ISSN={["1873-4030"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000279857300014&KeyUID=WOS:000279857300014}, DOI={10.1016/j.medengphy.2010.04.003}, abstractNote={Custom orthopedic implants may be generated using free-form fabrication methods (FFF) such as electron beam melting (EBM). EBM FFF may be used to make solid metal implants whose surface is often polished using CNC machining and porous scaffolds that are usually left unpolished. We assessed the in vitro biocompatibility of EBM titanium–6 aluminum–4 vanadium (Ti6Al4V) structures by comparing the cellular response to solid polished, solid unpolished, and porous EBM discs to the cellular response to discs made of commercially produced Ti6Al4V. The discs were seeded with 20,000 human adipose-derived adult stem cells (hASCs) and assessed for cell viability, proliferation, and release of the proinflammatory cytokines interleukin-6 (IL-6) and interleukin-8 (IL-8). Cell viability was assessed with Live/Dead staining 8 days after seeding. Cell proliferation was assessed using alamarBlue assays at days 0, 1, 2, 3, and 7. The hASCs were alive on all discs after 8 days. Cellular proliferation on porous EBM discs was increased at days 2, 3, and 7 compared to discs made of commercial Ti6Al4V. Cellular proliferation on porous EBM discs was also increased compared to solid polished and unpolished EBM discs. IL-6 and IL-8 releases at day 7 were lower for porous EBM discs than for other discs. Solid polished, unpolished, and porous EBM Ti6Al4V discs exhibited an acceptable biocompatibility profile compared to solid Ti6Al4V discs from a commercial source. EBM FFF may be considered as an option for the fabrication of custom orthopedic implants.}, number={6}, journal={MEDICAL ENGINEERING & PHYSICS}, author={Haslauer, Carla Maria and Springer, Jessica Collins and Harrysson, Ola L. A. and Loboa, Elizabeth G. and Monteiro-Riviere, Nancy A. and Marcellin-Little, Denis J.}, year={2010}, month={Jul}, pages={645–652} }
 @article{marcellin-little_cansizoglu_harrysson_roe_2010, title={In vitro evaluation of a low-modulus mesh canine prosthetic hip stem}, volume={71}, ISSN={["1943-5681"]}, DOI={10.2460/ajvr.71.9.1089}, abstractNote={Abstract
Objective—To compare an electron beam melting-processed (EBMP) low-modulus titanium alloy mesh stem with a commercial cobalt-chromium (CC) stem in a canine cadaver model.
Sample Population—9 pairs of cadaver femora.
Procedures—EBMP stems of 3 sizes were placed in randomly chosen sides of femora (left or right) and CC stems in opposite sides. Stem impaction distances were recorded. Five strain gauges were attached to the femoral surface to record transverse tensile (hoop) strains in the femur during axial loading. Constructs were axially loaded 4 times to 800 N and 4 times to 1,600 N in a materials testing machine. Axial stiffness of constructs and bone surface strains were compared between EBMP and CC constructs.
Results—Stems were impacted without creating femoral fissures or fractures. Stem impaction distances were larger for EBMP stems than for CC stems. Mean axial stiffness of EBMP constructs was lower than mean axial stiffness of CC constructs. Subsidence did not differ between groups. Bone strains varied among strain gauge positions and were largest at the distal aspect of the stems. At a load of 1,600 N, bones strains were higher in CC constructs than in EBMP constructs for 2 of 4 medial strain gauges.
Conclusions and Clinical Relevance—EBMP stems were successfully impacted and stable and led to a focal decrease in bone strain; this may represent an acceptable option for conventional or custom joint replacement. (Am J Vet Res 2010;71:1089–1095)
Although cemented hip stems have been used successfully as part of total hip replacements in humans, their success rate has been reportedly lower in younger patients than in older patients.1 The longterm success of hip stems is affected by aseptic implant loosening, implant wear, and stress-mediated bone resorption (stress shielding).2 Cementless hip stems were originally developed in part because polymethylmethacrylate bone cement was considered to be a contributing factor to aseptic loosening of cemented hip stems.3 A portion of a cementless stem is textured or coated with porous surfaces for bone ongrowth and ingrowth.4,5 Stem stability relies on initial press fit and long-term bone ingrowth into the porous portions of the stems. Cementless stems are large and have a high}, number={9}, journal={AMERICAN JOURNAL OF VETERINARY RESEARCH}, author={Marcellin-Little, Denis J. and Cansizoglu, Omer and Harrysson, Ola L. A. and Roe, Simon C.}, year={2010}, month={Sep}, pages={1089–1095} }
 @article{cansizoglu_harrysson_west_cormier_mahale_2008, title={Applications of structural optimization in direct metal fabrication}, volume={14}, ISSN={["1355-2546"]}, DOI={10.1108/13552540810862082}, abstractNote={PurposeOptimization techniques can be used to design geometrically complex components with a wide variety of optimization criteria. However, such components have been very difficult and costly to produce. Layered fabrication technologies such as electron beam melting (EBM) open up new possibilities though. This paper seeks to investigate the integration of structural optimization and direct metal fabrication process.Design/methodology/approachMesh structures were designed, and optimization problems were defined to improve structural performance. Finite element analysis code in conjunction with nonlinear optimization routines were used in MATLAB. Element data were extracted from an STL‐file, and output structures from the optimization routine were manufactured using an EBM machine. Original and optimized structures were tested and compared.FindingsThere were discrepancies between the performance of the theoretical structures and the physical EBM structures due to the layered fabrication approach. A scaling factor was developed to account for the effect of layering on the material properties.Practical implicationsStructural optimization can be used to improve the performance of a design, and direct fabrication technologies can be used to realise these structures. However, designers must realize that fabricated structures are not identical to idealized CAD structures, hence material properties much be adjusted accordingly.Originality/valueIntegration of structural optimization and direct metal fabrication was reported in the paper. It shows the process from design through manufacturing with integrated analysis.}, number={2}, journal={RAPID PROTOTYPING JOURNAL}, author={Cansizoglu, Omer and Harrysson, Ola L. A. and West, Harvey A., II and Cormier, Denis R. and Mahale, Tushar}, year={2008}, pages={114–122} }
 @article{marcellin-little_harrysson_cansizoglu_2008, title={In vitro evaluation of a custom cutting jig and custom plate for canine tibial plateau leveling}, volume={69}, ISSN={["1943-5681"]}, DOI={10.2460/ajvr.69.7.961}, abstractNote={Abstract
Objective—To design and manufacture custom titanium bone plates and a custom cutting and drill guide by use of free-form fabrication methods and to compare variables and mechanical properties of 2 canine tibial plateau leveling methods with each other and with historical control values.
Sample Population—10 canine tibial replicas created by rapid prototyping methods.
Procedures—Application time, accuracy of correction of the tibial plateau slope (TPS), presence and magnitude of rotational and angular deformation, and replica axial stiffness for 2 chevron wedge osteotomy (CWO) methods were assessed. One involved use of freehand CWO (FHCWO) and screw hole drilling, whereas the other used jig-guided CWO (JGCWO) and screw hole drilling.
Results—Replicas used for FHCWO and JGCWO methods had similar stiffness. Although JGCWO and FHCWO did not weaken the replicas, mean axial stiffness of replicas after JGCWO was higher than after FHCWO. The JGCWO method was faster than the FHCWO method. Mean ± SD TPS after osteotomy was lower for FHCWO (4.4 ± 1.1°) than for JGCWO (9.5 ± 0.4°), and JGCWO was more accurate (target TPS, 8.9°). Slight varus was evident after FHCWO but not after JGCWO. Mean postoperative rotation after JGCWO and FHCWO did not differ from the target value or between methods.
Conclusions and Clinical Relevance—The JGCWO method was more accurate and more rapid and resulted in more stability than the FHCWO method. Use of custom drill guides could enhance the speed, accuracy, and stability of corrective osteotomies in dogs.}, number={7}, journal={AMERICAN JOURNAL OF VETERINARY RESEARCH}, author={Marcellin-Little, Denis J. and Harrysson, Ola L. A. and Cansizoglu, Omer}, year={2008}, month={Jul}, pages={961–966} }
 @article{cansizoglu_harrysson_cormier_west_mahale_2008, title={Properties of Ti-6Al-4V non-stochastic lattice structures fabricated via electron beam melting}, volume={492}, ISSN={["0921-5093"]}, DOI={10.1016/j.msea.2008.04.002}, abstractNote={This paper addresses foams which are known as non-stochastic foams, lattice structures, or repeating open cell structure foams. The paper reports on preliminary research involving the design and fabrication of non-stochastic Ti–6Al–4V alloy structures using the electron beam melting (EBM) process. Non-stochastic structures of different cell sizes and densities were investigated. The structures were tested in compression and bending, and the results were compared to results from finite element analysis simulations. It was shown that the build angle and the build orientation affect the properties of the lattice structures. The average compressive strength of the lattice structures with a 10% relative density was 10 MPa, the flexural modulus was 200 MPa and the strength to density ration was 17. All the specimens were fabricated on the EBM A2 machine using a melt speed of 180 mm/s and a beam current of 2 mA. Future applications and FEA modeling were discussed in the paper.}, number={1-2}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Cansizoglu, O. and Harrysson, O. and Cormier, D. and West, H. and Mahale, T.}, year={2008}, month={Sep}, pages={468–474} }
 @article{liska_marcellin-little_eskelinen_sidebotham_harrysson_hielm-bjorkman_2007, title={Custom total knee replacement in a dog with femoral condylar bone loss}, volume={36}, ISSN={["0161-3499"]}, DOI={10.1111/j.1532-950X.2007.00270.x}, abstractNote={Objective— To report surgical planning, technique, and outcome of custom total knee replacement (TKR) performed to manage a medial femoral condylar nonunion in a dog.Study Design— Clinical case report.Animal— A 3‐year‐old, 20 kg Karelian Bear Hound.Methods— Computed tomographic scan of the left pelvic limb was used to build a stereolithography model of the distal portion of the femur. The model was used to create a custom augment to replace the missing medial femoral condyle and a custom stem for intramedullary condylar cemented fixation. The augment and stem were adapted to femoral and tibial components already available. The model was used to rehearse the surgery and then the custom prosthesis was implanted.Results— Weight bearing returned 8 hours after surgery and improved thereafter. Joint alignment was normal and prosthetic joint motion was 60–165° postoperatively. The dog resumed moose hunting 3 months after surgery. Peak vertical force and impulse of the operated limb measured 17 months after surgery were 65% and 47% of the normal, contralateral limb.Conclusion— Based on short‐term follow‐up, cemented canine TKR was successfully achieved for management of a severely abnormal stifle joint.Clinical Relevance— With further refinement and development of commercially available prostheses, TKR should be possible for canine patients.}, number={4}, journal={VETERINARY SURGERY}, author={Liska, William D. and Marcellin-Little, Denis J. and Eskelinen, Esa V. and Sidebotham, Christopher G. and Harrysson, Ola L. A. and Hielm-Bjorkman, Anna K.}, year={2007}, month={Jun}, pages={293–301} }
 @article{la harrysson_hosni_nayfeh_2007, title={Custom-designed orthopedic implants evaluated using finite element analysis of patient-specific computed tomography data: femoral-component case study}, volume={8}, ISSN={["1471-2474"]}, DOI={10.1186/1471-2474-8-91}, abstractNote={Conventional knee and hip implant systems have been in use for many years with good success. However, the custom design of implant components based on patient-specific anatomy has been attempted to overcome existing shortcomings of current designs. The longevity of cementless implant components is highly dependent on the initial fit between the bone surface and the implant. The bone-implant interface design has historically been limited by the surgical tools and cutting guides available; and the cost of fabricating custom-designed implant components has been prohibitive. This paper describes an approach where the custom design is based on a Computed Tomography scan of the patient's joint. The proposed design will customize both the articulating surface and the bone-implant interface to address the most common problems found with conventional knee-implant components. Finite Element Analysis is used to evaluate and compare the proposed design of a custom femoral component with a conventional design. The proposed design shows a more even stress distribution on the bone-implant interface surface, which will reduce the uneven bone remodeling that can lead to premature loosening. The proposed custom femoral component design has the following advantages compared with a conventional femoral component. (i) Since the articulating surface closely mimics the shape of the distal femur, there is no need for resurfacing of the patella or gait change. (ii) Owing to the resulting stress distribution, bone remodeling is even and the risk of premature loosening might be reduced. (iii) Because the bone-implant interface can accommodate anatomical abnormalities at the distal femur, the need for surgical interventions and fitting of filler components is reduced. (iv) Given that the bone-implant interface is customized, about 40% less bone must be removed. The primary disadvantages are the time and cost required for the design and the possible need for a surgical robot to perform the bone resection. Some of these disadvantages may be eliminated by the use of rapid prototyping technologies, especially the use of Electron Beam Melting technology for quick and economical fabrication of custom implant components.}, journal={BMC MUSCULOSKELETAL DISORDERS}, author={La Harrysson, Ola and Hosni, Yasser A. and Nayfeh, Jamal F.}, year={2007}, month={Sep} }
 @article{harrysson_cansizoglu_marcellin-little_cormier_west_2008, title={Direct metal fabrication of titanium implants with tailored materials and mechanical properties using electron beam melting technology}, volume={28}, ISSN={["0928-4931"]}, DOI={10.1016/j.msec.2007.04.022}, abstractNote={The design of custom or tailored implant components has been the subject of research and development for decades. However, the economic feasibility of fabricating such components has proven to be a challenge. New direct metal fabrication technologies such as Electron Beam Melting (EBM) have opened up new possibilities. This paper discusses the design and fabrication of titanium implant components having tailored mechanical properties that mimic the stiffness of bone to reduce stress shielding and bone remodeling. Finite Element Analysis was used to design the tailored structures, and results were verified using mechanical testing.}, number={3}, journal={MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS}, author={Harrysson, Ola L. A. and CansiZoglu, Omer and Marcellin-Little, Denis J. and Cormier, Denis R. and West, Harvey A., II}, year={2008}, month={Apr}, pages={366–373} }
 @article{hildreth_marcellin-little_roe_harrysson_2006, title={In vitro evaluation of five canine tibial plateau leveling methods}, volume={67}, ISSN={["1943-5681"]}, DOI={10.2460/ajvr.67.4.693}, abstractNote={Abstract
Objective—To compare application time, accuracy of tibial plateau slope (TPS) correction, presence and magnitude of rotational and angular deformities, and mechanical properties of 5 canine tibial plateau leveling methods.
Sample Population—27 canine tibial replicas created by rapid prototyping methods.
Procedure—The application time, accuracy of TPS correction, presence and magnitude of rotational and angular deformation, and construct axial stiffness of 3 internal fixation methods (tibial plateau leveling osteotomy, tibial wedge osteotomy, and chevron wedge osteotomy [CWO]) and 2 external skeletal fixation (ESF) methods (hinged hybrid circular external fixation and wedge osteotomy linear fixation [WOLF]) were assessed.
Results—Mean bone model axial stiffness did not differ among methods. Mean application time was more rapid for WOLF than for other methods. Mean TPSs did not differ from our 5° target and were lower for ESF methods, compared with internal fixation methods. Mean postoperative rotational malalignment did not differ from our target or among groups. Mean postoperative medio-lateral angulation did not differ from our target, except for CWO. Internal fixation methods lead to axially stiffer constructs than ESF methods. Reuse of ESF frames did not lead to a decrease in axial stiffness.
Conclusions and Clinical Relevance—The 5 tibial plateau leveling methods had acceptable geometric and mechanical properties. External skeletal fixation methods were more accurate as a result of precise data available for determining the exact magnitude of correction required to achieve a 5° TPS.}, number={4}, journal={AMERICAN JOURNAL OF VETERINARY RESEARCH}, author={Hildreth, BE and Marcellin-Little, DJ and Roe, SC and Harrysson, OLA}, year={2006}, month={Apr}, pages={693–700} }
 @article{osmond_marcellin-little_harrysson_kidd_2006, title={Morphometric assessment of the proximal portion of the tibia in dogs with and without cranial cruciate ligament rupture}, volume={47}, ISSN={["1740-8261"]}, DOI={10.1111/j.1740-8261.2006.00119.x}, abstractNote={Based on the clinical observation that dogs with a steep tibial plateau slope had variable tibial morphology, we hypothesized that these dogs could be further characterized using measurements developed by examining computer generated models of specific proximal tibial malformations. A 3D tibial model was created from a normal canine tibia. The model was manipulated to reproduce two specific proximal tibial anomalies representing deformities originating from the tibial plateau or the proximal tibial shaft. Data from these models were used to create specific measurements that would characterize the shape of these anomalies. These measurements included the diaphyseal tibial axis (DTA)/proximal tibial axis (PTA) angle, which defined the orientation of the proximal portion of the shaft in relation to the tibial mid‐shaft. These measurements were then made on radiographs of dogs with and without cranial cruciate ligament (CCL) rupture. Models with tibial plateau and proximal shaft deformities had a steep tibial plateau slope (TPS). Models with proximal shaft deformity had a markedly increased DTA/PTA angle. The model with a 10° proximal shaft deformity had a DTA/PTA angle of 11.23°. Six dogs (9.0%) had a DTA/PTA angle larger than 11.23° (range, 11.4–13.9°). Dogs in this group had ruptured CCL and a steep TPS. Dogs with CCL rupture had higher TPS (mean, 31.8±4.1°) and DTA/PTA angle (mean, 6.0±3.3°) than dogs without CCL rupture (means, 23.6±3.4° and 4.1±2.2°, respectively). Dogs with proximal shaft deformity represented a distinct group, which could not be identified using the magnitude of the TPS alone. Characterizing more precisely the shape of the proximal portion of the tibia in dogs contributes to our understanding of the pathogenesis of steep TPS and may facilitate the optimization of the surgical management of dogs with CCL rupture.}, number={2}, journal={VETERINARY RADIOLOGY & ULTRASOUND}, author={Osmond, CS and Marcellin-Little, DJ and Harrysson, OLA and Kidd, LB}, year={2006}, pages={136–141} }
 @article{cormier_harrysson_west_2004, title={Characterization of H13 steel produced via electron beam melting}, volume={10}, ISSN={["1355-2546"]}, DOI={10.1108/13552540410512516}, abstractNote={Electron beam melting (EBM) is a direct‐metal freeform fabrication technique in which a 4 kW electron beam is used to melt metal powder in a layer‐wise fashion. As this process is relatively new, there have not yet been any independently published studies on the H13 steel microstructural properties. This paper describes the EBM process and presents results of microstructural analyses on H13 tool steel processed via EBM.}, number={1}, journal={RAPID PROTOTYPING JOURNAL}, author={Cormier, D and Harrysson, A and West, H}, year={2004}, pages={35–41} }
 @article{harrysson_robertsson_nayfeh_2004, title={Higher cumulative revision rate of knee arthroplasties in younger patients with osteoarthritis}, ISSN={["0009-921X"]}, DOI={10.1097/01.blo.0000127115.05754.ce}, abstractNote={This study was designed to test the hypothesis that younger patients treated for osteoarthritis and similar conditions using total knee arthroplasty and unicompartmental knee arthroplasty have a lower implant survival rate when compared with older patients. Previous studies have been done on a small number of patients and only included the younger patients. In many cases patients treated for rheumatoid arthritis have been included in the studies and exceptional survival rates have been reported. The current study compared the cumulative revision rate of the components in 33,251 patients older than 60 years and 2606 patients younger than 60 years treated with total knee arthroplasty or unicompartmental knee arthroplasty for osteoarthritis or similar conditions. Cox regression was used to compare the risk for revision between the two age groups and between gender and the effect of year of operation. The results showed a higher cumulative revision rate for the group of younger patients in all statistical analyses and the risk ratio for revision was significantly lower for the group of older patients. The risk for revision decreased for both groups when considering the year of surgery. This is probably attributable to better implant components and surgical techniques.}, number={421}, journal={CLINICAL ORTHOPAEDICS AND RELATED RESEARCH}, author={Harrysson, OLA and Robertsson, O and Nayfeh, JF}, year={2004}, month={Apr}, pages={162–168} }
 @article{harrysson_cormier_marcellin-little_jajal_2003, title={Rapid prototyping for treatment of canine limb deformities}, volume={9}, ISSN={["1355-2546"]}, DOI={10.1108/13552540310455647}, abstractNote={This report describes Rapid Prototyping (RP) ‐aided assessment and preoperative planning for treatment of bilateral multifocal pelvic limb deformities in a 1 year old German Shepherd dog. Computed tomography (CT) scans were acquired on a General Electric CT scanner and converted to solid models using Mimics software from Materialise. Stereolithography patterns were prototyped using QuickCast build style on a SLA ‐190. Room temperature vulcanized silicone molds were constructed and three sets of polyurethane patterns were cast for pre‐surgical planning and rehearsal. The paper compares traditional osteotomy planning procedures using only radiographs and 2D CT images to planning with full‐scale physical biomodels. The biomodels had a clearly beneficial impact on the accuracy of surgery and positively influenced the clinical outcome.}, number={1}, journal={RAPID PROTOTYPING JOURNAL}, author={Harrysson, OLA and Cormier, DR and Marcellin-Little, DJ and Jajal, K}, year={2003}, pages={37–42} }