@article{koprov_gadhwala_walimbe_fang_starly_2023, title={Systems and methods for authenticating manufacturing Machines through an unobservable fingerprinting system}, volume={35}, ISSN={2213-8463}, url={http://dx.doi.org/10.1016/j.mfglet.2023.08.051}, DOI={10.1016/j.mfglet.2023.08.051}, abstractNote={Digital transformation leads to the inevitable change in the security paradigm for machines on a factory production floor. A unified namespace for machines in an Industrial Internet of Things (IIoT) network is only reliable when machine assets can trust and verify the identity of assets connected to the IIoT system. Current methods of asset authentication do not consider physical unclonable functions (PUFs) and can easily be spoofed or misused. Our work proposes using PUFs for industrial equipment such as CNC machines, robots, and 3D printers for identifying machines on a network and providing authentication procedures. In this work, we chose to use the vibration associated with machines and its embedded moving parts as a means to identify machine assets on a network. It is hypothesized that the vibrations associated with specific machine movements will be unique to each machine even when machines look exactly the same. The moving parts within a machine may produce a unique vibration pattern that can be used for machine identification throughout the working cycle. Our method requires light computing and relatively cheap measuring devices to capture the ‘fingerprints’ of machines and verify the signal's integrity. An adequate number of equipment has been tested for the worst-case scenario, i.e. when two machines look exactly the same with the same moving parts and produce exactly similar motion to generate the vibration signal. Data preprocessing and standard machine learning techniques like RF, LASSO, and SVM show great performance on raw time series data, enabling 100% TPR and more than 94% TNR in detecting the false class of the machines.}, journal={Manufacturing Letters}, publisher={Elsevier BV}, author={Koprov, Pavel and Gadhwala, Shyam and Walimbe, Aniket and Fang, Xiaolei and Starly, Binil}, year={2023}, month={Aug}, pages={1009–1018} }
 @article{starly_koprov_bharadwaj_batchelder_breitenbach_2023, title={“Unreal” factories: Next generation of digital twins of machines and factories in the Industrial Metaverse}, volume={37}, ISSN={2213-8463}, url={http://dx.doi.org/10.1016/j.mfglet.2023.07.021}, DOI={10.1016/j.mfglet.2023.07.021}, abstractNote={In its current technology form, digital twins are 3D representations that still lack the realism necessary to enable digital twins to progress towards virtual collaboration and high-fidelity simulation. In this short paper, ten technologies necessary to build the next generation of digital twins of factories are elucidated with a focus on real-time rendering while capturing dynamic states within machines, two-way real-time data transfer between assets and synthetic generation of factory states. Potential applications are also outlined to enable the community to further imagine technology needs and research questions that arise as the next generation of Digital twins are developed.}, journal={Manufacturing Letters}, publisher={Elsevier BV}, author={Starly, Binil and Koprov, Pavel and Bharadwaj, Akshay and Batchelder, Thomas and Breitenbach, Bennett}, year={2023}, month={Sep}, pages={50–52} }
 @article{bharadwaj_starly_2022, title={Knowledge graph construction for product designs from large CAD model repositories}, volume={53}, ISSN={["1873-5320"]}, DOI={10.1016/j.aei.2022.101680}, abstractNote={Product Design based Knowledge graphs (KG) aid the representation of product assemblies through heterogeneous relationships that link entities obtained from multiple structured and unstructured sources. This study describes an approach to constructing a multi-relational and multi-hierarchical knowledge graph that extracts information contained within the 3D product model data to construct Assembly-Subassembly-Part and Shape Similarity relationships. This approach builds on a combination of utilizing 3D model meta-data and structuring the graph using the Assembly-Part hierarchy alongside 3D Shape-based Clustering. To demonstrate our approach, from a dataset consisting of 110,770 CAD models, 92,715 models were organized into 7,651 groups of varying sizes containing highly similar shapes, demonstrating the varied nature of design repositories, but inevitably also containing a significant number of repetitive and unique designs. Using the Product Design Knowledge Graph, we demonstrate the effectiveness of 3D shape retrieval using Approximate Nearest Neighbor search. Finally, we illustrate the use of the KG for Design Reuse of co-occurring components, Rule-Based Inference for Assembly Similarity and Collaborative Filtering for Multi-Modal Search of manufacturing process conditions. Future work aims to expand the KG to include downstream data within product manufacturing and towards improved reasoning methods to provide actionable suggestions for design bot assistants and manufacturing automation.}, journal={ADVANCED ENGINEERING INFORMATICS}, author={Bharadwaj, Akshay G. and Starly, Binil}, year={2022}, month={Aug} }
 @article{kumar_starly_2021, title={"FabNER": information extraction from manufacturing process science domain literature using named entity recognition}, volume={6}, ISSN={["1572-8145"]}, url={https://doi.org/10.1007/s10845-021-01807-x}, DOI={10.1007/s10845-021-01807-x}, number={8}, journal={JOURNAL OF INTELLIGENT MANUFACTURING}, author={Kumar, Aman and Starly, Binil}, year={2021}, month={Jun} }
 @article{kapadia_uzsoy_starly_warsing_2021, title={A genetic algorithm for order acceptance and scheduling in additive manufacturing}, volume={10}, ISSN={["1366-588X"]}, DOI={10.1080/00207543.2021.1991023}, abstractNote={ABSTRACT We consider the problem of order acceptance and scheduling faced by an additive manufacturing facility consisting of multiple build chambers and postprocessing operations for support removal and surface finishing. We model each build chamber as a batch processing machine with processing times determined by the nesting and orientation of parts within the chamber. Due to the difficulty of developing an explicit functional relation between part batching, batch processing time, and postprocessing requirements we develop random-keys based genetic algorithms to select orders for complete or partial acceptance and produce a high-quality schedule satisfying all technological constraints, including part orientation and rotation within the build chamber. Extensive computational experiments show that the proposed approaches yield significant improvements in profit over the situation where all orders must be accepted, and produce solutions that compare favourably to statistically estimated bounds.}, journal={INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH}, author={Kapadia, Maaz Saleem and Uzsoy, Reha and Starly, Binil and Warsing, Donald P., Jr.}, year={2021}, month={Oct} }
 @article{pahwa_starly_2021, title={Dynamic matching with deep reinforcement learning for a two-sided Manufacturing-as-a-Service (MaaS) marketplace}, volume={29}, ISSN={["2213-8463"]}, DOI={10.1016/j.mfglet.2021.05.005}, abstractNote={Suppliers registered within a manufacturing-as-a-service (MaaS) marketplace require near real time decision making to accept or reject orders received on the platform. Myopic decision-making such as a first come, first serve method in this dynamic and stochastic environment can lead to suboptimal revenue generation. In this paper, this sequential decision making problem is formulated as a Markov Decision Process and solved using deep reinforcement learning (DRL). Empirical simulations demonstrate that DRL has considerably better performance compared to four baselines. This early work demonstrates a learning approach for near real-time decision making for suppliers participating in a MaaS marketplace.}, journal={MANUFACTURING LETTERS}, author={Pahwa, Deepak and Starly, Binil}, year={2021}, month={Aug}, pages={11–14} }
 @article{hasan_ogan_starly_2021, title={Hybrid Blockchain Architecture for Cloud Manufacturing-as-a-service (CMaaS) Platforms with Improved Data Storage and Transaction Efficiency}, volume={53}, ISSN={["2351-9789"]}, DOI={10.1016/j.promfg.2021.06.060}, abstractNote={Blockchain based decentralized Cloud Manufacturing-as-a-Service (CMaaS) platforms enable customers to gain access to a large capacity of manufacturing nodes over cryptographically secure networks. In recent times, the Ethereum network has emerged as a popular blockchain framework for providing provenance and traceability of proprietary manufacturing data in decentralized CMaaS. However, the Ethereum ecosystem was only designed to store and transmit low volume financial transaction data and little has been done to make it an efficient repository of large manufacturing data streams in CMaaS systems. In this paper, the authors build on their previous work and report the design, implementation, and validation of middleware software architectures that allow Ethereum based distributed CMaaS platforms to harness the benefits of the secure asset models of the Ethereum ecosystem and the immutable big data storage capabilities of the decentralized BigchainDB database platform. A novel hybrid blockchain architecture enabled by efficient communication protocols and blockchain oracles is proposed. This architecture allows the transfer and immutable storage of large manufacturing data streams onto global BigchainDB nodes allowing data rich manufacturing transactions to bypass the transaction fees of the Ethereum ecosystem. Additionally, a machine learning based time series inference model is proposed which enables the forecast of Ethereum gas price into the future. This allows the CMaaS platform smart contracts to judiciously assign gas price limits and hence save on transactions ensuing from transfer or creation of assets. The outcomes of this research show that the designed hybrid architecture can lead to the reduction of significant number of computational steps and hence transaction fees on Ethereum by offloading large volume data onto BigchainDB nodes. A Random Forest regressor based time series inference model has been shown to exhibit superior performance in the prediction of Ethereum gas price, that allows the CMaaS to avoid executing transactions in periods of high gas prices within the Ethereum ecosystem.}, journal={49TH SME NORTH AMERICAN MANUFACTURING RESEARCH CONFERENCE (NAMRC 49, 2021)}, author={Hasan, Mahmud and Ogan, Kemafor and Starly, Binil}, year={2021}, pages={594–605} }
 @article{angrish_bharadwaj_starly_2021, title={MVCNN plus plus : Computer-Aided Design Model Shape Classification and Retrieval Using Multi-View Convolutional Neural Networks}, volume={21}, ISBN={1944-7078}, DOI={10.1115/1.4047486}, abstractNote={
 Deep neural networks (DNNs) have been successful in classification and retrieval tasks of images and text, as well as in the graphics domain. However, these DNNs algorithms do not translate to 3D engineering models used in the product design and manufacturing. This paper studies the use of multi-view convolutional neural network (MVCNN) algorithm enhanced by the addition of engineering metadata, for classification and retrieval of 3D computer-aided design (CAD) models. The proposed algorithm (MVCNN++) builds on the MVCNN algorithm with the addition of part dimension data, improving its efficacy for manufacturing part classification and yielding an improvement in classification accuracy of 5.8% over the original version. Unlike datasets used for 3D shape classification and retrieval in the computer graphics domain, engineering level description of 3D CAD models do not yield themselves to neat, distinct classes. Techniques such as relaxed-classification and prime angled cameras for capturing feature detail were used to address training data capture issues specific to 3D CAD models, along with the use of transfer learning to reduce training time. Our study has shown that DNNs can be used to search and discover relevant 3D engineering models in large public repositories, making 3D models accessible to the community.}, number={1}, journal={JOURNAL OF COMPUTING AND INFORMATION SCIENCE IN ENGINEERING}, author={Angrish, Atin and Bharadwaj, Akshay and Starly, Binil}, year={2021} }
 @article{shohan_harm_hasan_starly_shirwaiker_2021, title={Non-destructive quality monitoring of 3D printed tissue scaffolds via dielectric impedance spectroscopy and supervised machine learning}, volume={53}, ISSN={["2351-9789"]}, url={http://dx.doi.org/10.1016/j.promfg.2021.06.063}, DOI={10.1016/j.promfg.2021.06.063}, abstractNote={Majority of methods currently used for quality assessment of tissue engineered medical products (TEMPs) are offline and destructive in nature, which is one of the factors impeding the scale up and translation of these technologies. In this study, we investigate quality assessment of TEMP via dielectric impedance spectroscopy (DIS) and supervised machine learning (ML) as a non-destructive alternative that requires minimal human intervention. 3D printed, NaOH-treated polycaprolactone (PCL) scaffolds seeded with human adipose-derived stem cells (hASC), NIH 3T3, MG63, and human chondrocyte cells were assessed via DIS over 4 days of in vitro culture. The results showed that the cell type and duration in culture had a significant effect on the delta permittivity (Δε, an important DIS metric. Five supervised ML algorithms – K Nearest Neighbors (KNN), Logistic Regression, Random Forest Classifiers, Support Vector Machines, and artificial neural network – were then used to analyze the comprehensive structured permittivity datasets to determine their ability to discern between different cell types and culture durations. The KNN algorithm demonstrated the best accuracy (99%). The outcomes of this study demonstrate the approach of using DIS and supervised ML in conjunction for assessment of TEMPs in an automated manufacturing system.}, journal={49TH SME NORTH AMERICAN MANUFACTURING RESEARCH CONFERENCE (NAMRC 49, 2021)}, publisher={Elsevier BV}, author={Shohan, Shohanuzzaman and Harm, Jordan and Hasan, Mahmud and Starly, Binil and Shirwaiker, Rohan}, year={2021}, pages={636–643} }
 @article{zhang_zeng_starly_2021, title={Recurrent neural networks with long term temporal dependencies in machine tool wear diagnosis and prognosis}, volume={3}, ISSN={["2523-3971"]}, DOI={10.1007/s42452-021-04427-5}, abstractNote={Abstract Data-driven approaches for machine tool wear diagnosis and prognosis are gaining attention in the past few years. The goal of our study is to advance the adaptability, flexibility, prediction performance, and prediction horizon for online monitoring and prediction. This paper proposes the use of a recent deep learning method, based on Gated Recurrent Neural Network architecture, including Long Short Term Memory (LSTM), which try to captures long-term dependencies than regular Recurrent Neural Network method for modeling sequential data, and also the mechanism to realize the online diagnosis and prognosis and remaining useful life (RUL) prediction with indirect measurement collected during the manufacturing process. Existing models are usually tool-specific and can hardly be generalized to other scenarios such as for different tools or operating environments. Different from current methods, the proposed model requires no prior knowledge about the system and thus can be generalized to different scenarios and machine tools. With inherent memory units, the proposed model can also capture long-term dependencies while learning from sequential data such as those collected by condition monitoring sensors, which means it can be accommodated to machine tools with varying life and increase the prediction performance. To prove the validity of the proposed approach, we conducted multiple experiments on a milling machine cutting tool and applied the model for online diagnosis and RUL prediction. Without loss of generality, we incorporate a system transition function and system observation function into the neural net and trained it with signal data from a minimally intrusive vibration sensor. The experiment results showed that our LSTM-based model achieved the best overall accuracy among other methods, with a minimal Mean Square Error (MSE) for tool wear prediction and RUL prediction respectively.}, number={4}, journal={SN APPLIED SCIENCES}, author={Zhang, Jianlei and Zeng, Yukun and Starly, Binil}, year={2021}, month={Mar} }
 @article{starly_cohen_raman_2020, title={Automating the Search and Discovery of Manufacturing Service Providers to Enable a Digital Supply Chain Network}, volume={4}, ISSN={["2572-3928"]}, DOI={10.1520/SSMS20200061}, abstractNote={Uncertainty in manufacturing networks has created barriers to closing the gap between design enterprises and the American industrial base Uncertainty arises from the lack of transparent access to manufacturer capabilities, the inability to auto-discover service providers who are best capable for a given job request, and the dependence on human word-of-mouth trust network relationships that exist in the manufacturing supply chain This uncertainty slows down the pace of product development lifecycles from a viewpoint of inefficient forms of supplier assessment, vetting, selection, and compliance, leading to a trust tax tacked onto the final price of products In times of global crisis such as the coronavirus disease pandemic, this uncertainty also leads to inefficient forms of gathering information on manufacturing capability, available capacity, and registered licenses and assessing compliance This technical note outlines solution pathways that can help ease the search and discovery process of connecting clients and manufacturing service providers through digitally enabled technologies Copyright © 2020 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959}, number={3}, journal={SMART AND SUSTAINABLE MANUFACTURING SYSTEMS}, author={Starly, Binil and Cohen, Paul and Raman, Shivakumar}, year={2020}, month={Dec}, pages={276–280} }
 @article{hasan_starly_2020, title={Decentralized cloud manufacturing-as-a-service (CMaaS) platform architecture with configurable digital assets}, volume={56}, ISSN={["1878-6642"]}, DOI={10.1016/j.jmsy.2020.05.017}, abstractNote={Contemporary Cloud Manufacturing-as-a-Service (CMaaS) platforms now promise customers instant pricing and access to a large capacity of manufacturing nodes. However, many of the CMaaS platforms are centralized with data flowing through an intermediary agent connecting clients with service providers. This paper reports the design, implementation and validation of middleware software architectures which aim to directly connect client users with manufacturing service providers while improving transparency, data integrity, data provenance and retaining data ownership to its creators. In the first middleware, clients have the ability to directly customize and configure parts parametrically, leading to an instant generation of downstream manufacturing process plan codes. In the second middleware, clients can track the data provenance generated in a blockchain based decentralized architecture across a manufacturing system. The design of digital assets across a distributed manufacturing system infrastructure controlled by autonomous smart contracts through Ethereum based ERC-721 non-fungible tokens is proposed to enable communication and collaboration across decentralized CMaaS platform architectures. The performance of the smart contracts was evaluated on three different global Ethereum blockchain test networks with the centrality and dispersion statistics on their performance provided as a reference benchmark for future smart contract implementations.}, journal={JOURNAL OF MANUFACTURING SYSTEMS}, author={Hasan, Mahmud and Starly, Binil}, year={2020}, month={Jul}, pages={157–174} }
 @article{sun_starly_daly_burdick_groll_skeldon_shu_sakai_shinohara_nishikawa_et al._2020, title={The bioprinting roadmap}, volume={12}, ISSN={["1758-5090"]}, DOI={10.1088/1758-5090/ab5158}, abstractNote={This bioprinting roadmap features salient advances in selected applications of the technique and highlights the status of current developments and challenges, as well as envisioned advances in science and technology, to address the challenges to the young and evolving technique. The topics covered in this roadmap encompass the broad spectrum of bioprinting; from cell expansion and novel bioink development to cell/stem cell printing, from organoid-based tissue organization to bioprinting of human-scale tissue structures, and from building cell/tissue/organ-on-a-chip to biomanufacturing of multicellular engineered living systems. The emerging application of printing-in-space and an overview of bioprinting technologies are also included in this roadmap. Due to the rapid pace of methodological advancements in bioprinting techniques and wide-ranging applications, the direction in which the field should advance is not immediately clear. This bioprinting roadmap addresses this unmet need by providing a comprehensive summary and recommendations useful to experienced researchers and newcomers to the field.}, number={2}, journal={BIOFABRICATION}, author={Sun, Wei and Starly, Binil and Daly, Andrew C. and Burdick, Jason A. and Groll, Juergen and Skeldon, Gregor and Shu, Wenmiao and Sakai, Yasuyuki and Shinohara, Marie and Nishikawa, Masaki and et al.}, year={2020}, month={Apr} }
 @article{mehdi_starly_2020, title={Witness Box Protocol: Automatic machine identification and authentication in industry 4.0}, volume={123}, ISSN={["1872-6194"]}, DOI={10.1016/j.compind.2020.103340}, abstractNote={The current wave of Industrial Internet of Things (IIoT) is reshaping the manufacturing sector with system interoperability, remote real-time process monitoring and advanced analytics. As digitally enabled manufacturing machines continue to grow exponentially, it becomes imperative to uniquely and securely identify them in the cyber-physical world, particularly in defense, biomedical, energy and aerospace manufacturing. Research about threats originating from internal adversaries’ i.e the machine/organization owner within a tiered digitally connected supply chain is scarce. This paper introduces a machine fingerprinting scheme named as the ‘Witness Box Protocol’ (WBP) that exploits the physical properties of manufacturing machines (legacy or smart) and their surroundings to create a unique biometric like fingerprint. WBP provides both machine registration and authentication on a digital network through a low cost, non-invasive approach. The fingerprint is generated by a Locality Sensitive Hashing (LSH) technique that accommodates small variations in physical signature data and can corroborate data provenance from machines by verifying machine identity through authentication. Additionally, this fingerprint hash simplifies asset management within a large enterprise or distributed network comprising of thousands of machines in a Manufacturing-as-a-Service (MaaS) paradigm. In this research, fingerprints were randomly generated from the statistical features of signals from 3D printers and CNC machine in a production-like lab environment. Using k-means clustering and Jaccard similarity index, these fingerprints are shown to identify the source equipment with 95 % accuracy.}, journal={COMPUTERS IN INDUSTRY}, author={Mehdi, Nabeel and Starly, Binil}, year={2020}, month={Dec} }
 @article{latif_shao_starly_2019, title={Integrating A Dynamic Simulator and Advanced Process Control using the OPC-UA Standard}, volume={34}, ISSN={["2351-9789"]}, DOI={10.1016/j.promfg.2019.06.200}, abstractNote={Insufficient interoperability has long been an issue on the factory floor, however, new technologies and standards are enabling production systems to become more agile and interoperable. A communication standard can, for example, make interoperation among different vendor-specific software and hardware tools in production systems easier and more reliable. In this paper, we share our research results and experience for the establishment of a connection between a dynamic simulator and an advanced process controller in a manufacturing system using OPC-UA. The OPC-UA communication protocol, which is middleware, acts as a common interface between these systems. We established the client and server for communication and defined an exchange data structure based on the OPC-UA standard for a control problem in a chemical process plant. The case study is a proof of concept of the OPC-UA standard implementation to support interoperability for different domains.}, journal={47TH SME NORTH AMERICAN MANUFACTURING RESEARCH CONFERENCE (NAMRC 47)}, author={Latif, Hasan and Shao, Guodong and Starly, Binil}, year={2019}, pages={813–819} }
 @article{pahwa_starly_2019, title={Network-based pricing for 3D printing services in two-sided manufacturing-as-a-service marketplace}, volume={ahead-of-print}, ISSN={1355-2546 1355-2546}, url={http://dx.doi.org/10.1108/RPJ-01-2019-0018}, DOI={10.1108/rpj-01-2019-0018}, abstractNote={
Purpose
This paper presents approaches to determine a network-based pricing for 3D printing services in the context of a two-sided manufacturing-as-a-service marketplace. The purpose of this study is to provide cost analytics to enable service bureaus to better compete in the market by moving away from setting ad hoc and subjective prices.


Design/methodology/approach
A data mining approach with machine learning methods is used to estimate a price range based on the profile characteristics of 3D printing service suppliers. The model considers factors such as supplier experience, supplier capabilities, customer reviews and ratings from past orders and scale of operations, among others, to estimate a price range for suppliers’ services. Data were gathered from existing marketplace websites, which were then used to train and test the model.


Findings
The model demonstrates an accuracy of 65 per cent for US-based suppliers and 59 per cent for Europe-based suppliers to classify a supplier’s 3D printer listing in one of the seven price categories. The improvement over baseline accuracy of 25 per cent demonstrates that machine learning-based methods are promising for network-based pricing in manufacturing marketplaces


Originality/value
Conventional methodologies for pricing services through activity-based costing are inefficient in strategically priced 3-D printing service offering in a connected marketplace. As opposed to arbitrarily determining prices, this work proposes an approach to determine prices through data mining methods to estimate competitive prices. Such tools can be built into online marketplaces to help independent service bureaus to determine service price rates.
}, number={ahead-of-print}, journal={Rapid Prototyping Journal}, publisher={Emerald}, author={Pahwa, Deepak and Starly, Binil}, year={2019}, month={Aug} }
 @article{sherlekar_starly_cohen_2019, title={Provisioned Data Distribution for Intelligent Manufacturing via Fog Computing}, volume={34}, ISSN={["2351-9789"]}, DOI={10.1016/j.promfg.2019.06.158}, abstractNote={The number of ‘things’ ranging from simple devices to complex machines on the factory floor connected at the enterprise level and to the broader internet is growing exponentially. This connection also leads to a tremendous amount of data generated leading to ‘Data’ now considered one of the core assets in the broader manufacturing industry. However, the availability of this asset is hardly made use of by Small and Medium scale manufacturing enterprises (SME) - the ‘Mittelstand’ of America. How can certain types of data be shared by SME companies, yet have the ability to retain ownership and control over their own data? How does SME leverage computing on these diverse forms of data for the benefit of its clients and itself? In this paper, we propose a decentralized data distribution architecture to democratize the potential availability of large amounts of data generated by the manufacturing industry using the Fog Computing paradigm. The architecture leverages an Industry scalable middleware extension of Cloud manufacturing that securely filters and transmits data from IoT enabled manufacturing machines on the shop floor to potential users over the cloud. This work also demonstrates a data-centric approach which allows peer-to-peer data sharing laterally within the fog layer to serve cloud users. We demonstrate the feasibility of the Fog middleware infrastructure through case studies that involves various types of manufacturing data.}, journal={47TH SME NORTH AMERICAN MANUFACTURING RESEARCH CONFERENCE (NAMRC 47)}, author={Sherlekar, Riddhiman and Starly, Binil and Cohen, Paul H.}, year={2019}, pages={893–902} }
 @article{angrish_craver_starly_2019, title={“FabSearch”: A 3D CAD Model-Based Search Engine for Sourcing Manufacturing Services}, volume={19}, ISSN={1530-9827 1944-7078}, url={http://dx.doi.org/10.1115/1.4043211}, DOI={10.1115/1.4043211}, abstractNote={In this paper, we present “FabSearch,” a prototype search engine for sourcing manufacturing service providers, by making use of the product manufacturing information (PMI) contained within a 3D digital file of a part product. FabSearch is designed to take in a query 3D model, such as the .STEP file of a part model which then produces a ranked list of job shop service providers who are best suited to fabricate the part. Service providers may have potentially built hundreds to thousands of parts with associated part 3D models over time. FabSearch assumes that these service providers have shared shape signatures of the part models built previously to enable the algorithm to most effectively rank the service providers who have the most experience to build the query part model. FabSearch has two important features that helps it produce relevant results. First, it makes use of the shape characteristics of the 3D part by calculating the Spherical Harmonics signature of the part to calculate the most similar shapes built previously be job shop service providers. Second, FabSearch utilizes metadata about each part, such as material specification, tolerance requirements to help improve the search results based on the specific query model requirements. The algorithm is tested against a repository containing more than 2000 models distributed across various job shop service providers. For the first time, we show the potential for utilizing the rich information contained within a 3D part model to automate the sourcing and eventual selection of manufacturing service providers.}, number={4}, journal={Journal of Computing and Information Science in Engineering}, publisher={ASME International}, author={Angrish, Atin and Craver, Benjamin and Starly, Binil}, year={2019}, month={Jun} }
 @article{angrish_craver_hasan_starly_2018, title={A Case Study for Blockchain in Manufacturing: “FabRec”: A Prototype for Peer-to-Peer Network of Manufacturing Nodes}, volume={26}, ISSN={2351-9789}, url={http://dx.doi.org/10.1016/J.PROMFG.2018.07.154}, DOI={10.1016/J.PROMFG.2018.07.154}, abstractNote={With product customization an emerging business opportunity, organizations must find ways to collaborate and enable sharing of information in an inherently trust-less network. In this paper, we propose – “FabRec”: a decentralized approach to handle manufacturing information generated by various organizations using blockchain technology. We propose a system in which a decentralized network of manufacturing machines and computing nodes can enable automated transparency of an organization’s capability, third party verification of such capability through a trail of past historic events and automated mechanisms to drive paperless contracts between participants using ‘smart contracts’. Our system decentralizes critical information about the manufacturer and makes it available on a peer-to-peer network composed of fiduciary nodes to ensure transparency and data provenance through a verifiable audit trail. We present a testbed platform through a combination of manufacturing machines, system-on-chip platforms and computing nodes to demonstrate mechanisms through which a consortium of disparate organizations can communicate through a decentralized network. Our prototype testbed demonstrates the value of computer code residing on a decentralized network for verification of information on the blockchain and ways in which actions can be autonomously initiated in the physical world. This paper intends to expose system elements in preparation for much larger field tests through the working prototype and discusses the future potential of blockchain for manufacturing IT.}, journal={Procedia Manufacturing}, publisher={Elsevier BV}, author={Angrish, Atin and Craver, Benjamin and Hasan, Mahmud and Starly, Binil}, year={2018}, pages={1180–1192} }
 @article{narayanan_thompson_shirwaiker_starly_2018, title={Label free process monitoring of 3D bioprinted engineered constructs via dielectric impedance spectroscopy}, volume={10}, ISSN={["1758-5090"]}, DOI={10.1088/1758-5090/aaccbf}, abstractNote={Biofabrication processes can affect biological quality attributes of encapsulated cells within constructs. Currently, assessment of the fabricated constructs is performed offline by subjecting the constructs to destructive assays that require staining and sectioning. This drawback limits the translation of biofabrication processes to industrial practice. In this work, we investigate the dielectric response of viable cells encapsulated in bioprinted 3D hydrogel constructs to an applied alternating electric field as a label-free non-destructive monitoring approach. The relationship between β-dispersion parameters (permittivity change—Δε, Cole–Cole slope factor—α, critical polarization frequency—fc) over the frequency spectrum and critical cellular quality attributes are investigated. Results show that alginate constructs containing a higher number of viable cells (human adipose derived stem cells—hASC and osteosarcoma cell line—MG63) were characterized by significantly higher Δε and α (both p < 0.05). When extended to bioprinting, results showed that changes in hASC proliferation and viability in response to changes in critical bioprinting parameters (extrusion pressure, temperature, processing time) significantly affected ∆ε, α, and fc. We also demonstrated monitoring of hASC distribution after bioprinting and changes in proliferation over time across the cross-section of a bioprinted medial knee meniscus construct. The trends in ∆ε over time were in agreement with the alamarBlue assay results for the whole construct, but this measurement approach provided a localized readout on the status of encapsulated cells. The findings of this study support the use of dielectric impedance spectroscopy as a label-free and non-destructive method to characterize the critical quality attributes of bioprinted constructs.}, number={3}, journal={BIOFABRICATION}, author={Narayanan, Lokesh Karthik and Thompson, Trevor L. and Shirwaiker, Rohan A. and Starly, Binil}, year={2018}, month={Jul} }
 @article{sweeney_starly_morris_xu_jones_radhakrishnan_grassa_davis_2018, title={Large-scale digitization of herbarium specimens: Development and usage of an automated, high-throughput conveyor system}, volume={67}, ISSN={["1996-8175"]}, DOI={10.12705/671.9}, abstractNote={The billions of specimens housed in natural science collections provide a tremendous source of under-utilized data that are useful for scientific research, conservation, commerce, and education. Digitization and mobilization of specimen data and images promises to greatly accelerate their utilization. While digitization of natural science collection specimens has been occurring for decades, the vast majority of specimens remain un-digitized. If the digitization task is to be completed in the near future, innovative, high-throughput approaches are needed. To create a dataset for the study of global change in New England, we designed and implemented an industrial-scale, conveyor-based digitization workflow for herbarium specimen sheets. The workflow is a variation of an object-to-image-to-data workflow that prioritizes imaging and the capture of storage container-level data. The workflow utilizes a novel conveyor system developed specifically for the task of imaging flattened herbarium specimens. Using our workflow, we imaged and transcribed specimen-level data for almost 350,000 specimens over a 131-week period; an additional 56 weeks was required for storage container-level data capture. Our project has demonstrated that it is possible to capture both an image of a specimen and a core database record in 35 seconds per herbarium sheet (for intervals between images of 30 minutes or less) plus some additional overhead for container-level data capture. This rate was in line with the pre-project expectations for our approach. Our throughput rates are comparable with some other similar, highthroughput approaches focused on digitizing herbarium sheets and is as much as three times faster than rates achieved with more conventional non-automated approaches used during the project. We report on challenges encountered during development and use of our system and discuss ways in which our workflow could be improved. The conveyor apparatus software, database schema, configuration files, hardware list, and conveyor schematics are available for download on GitHub.}, number={1}, journal={TAXON}, author={Sweeney, Patrick W. and Starly, Binil and Morris, Paul J. and Xu, Yiming and Jones, Aimee and Radhakrishnan, Sridhar and Grassa, Christopher J. and Davis, Charles C.}, year={2018}, month={Feb}, pages={165–178} }
 @article{pahwa_starly_cohen_2018, title={Reverse auction mechanism design for the acquisition of prototyping services in a manufacturing-as-a-service marketplace}, volume={48}, ISSN={["1878-6642"]}, DOI={10.1016/j.jmsy.2018.05.005}, abstractNote={The affordability and increased capability of additive manufacturing machines has spawned prototyping service bureaus throughout the world. This poses a challenge to designers who are looking to obtain quality 3D printed parts at best available prices within fastest turnaround times. Customers relying on a sole source for 3D printed parts may have limited options in obtaining the best deals. From a service supplier point of view, filling excess capacity will require significant marketing budgets to reach and retain customers. In this paper, we present a novel mechanism design approach for improving the accessibility of prototyping services providers by leveraging their excess capacity. In our proposed mechanism, consumers name their own price and the mechanism will find service bureaus who are willing to make the part under the stated price. The mechanism runs similar to a reverse auction where consumers bid and the platform finds a service supplier which is able to match the stated bid price. The incentive for suppliers to participate in such a platform is the opportunity to market their excess capacity to a deal conscious consumer at a lower price without cannibalizing their existing sales channels. Qualified suppliers do not directly compete with each other for any given order since they are chosen using a two stage selection process by the service platform. This algorithm ensures that every supplier has a fair chance of selling its services on the platform regardless of price. We implement the proposed mechanism design approach in a simulated service marketplace and empirically evaluate the marketplace behavior by studying the impact of various model factors such as the supplier threshold price, the size and variety of suppliers in the marketplace.}, journal={JOURNAL OF MANUFACTURING SYSTEMS}, author={Pahwa, Deepak and Starly, Binil and Cohen, Paul}, year={2018}, month={Jul}, pages={134–143} }
 @article{angrish_starly_lee_cohen_2017, title={A flexible data schema and system architecture for the virtualization of manufacturing machines (VMM)}, volume={45}, ISSN={0278-6125}, url={http://dx.doi.org/10.1016/j.jmsy.2017.10.003}, DOI={10.1016/j.jmsy.2017.10.003}, abstractNote={Abstract Future factories will feature strong integration of physical machines and cyber-enabled software, working seamlessly to improve manufacturing production efficiency. In these digitally enabled and network connected factories, each physical machine on the shop floor can have its ‘virtual twin’ available in cyberspace. This ‘virtual twin’ is populated with data streaming in from the physical machines to represent a near real-time as-is state of the machine in cyberspace. This results in the virtualization of a machine resource to external factory manufacturing systems. This paper describes how streaming data can be stored in a scalable and flexible document schema based database such as MongoDB, a data store that makes up the virtual twin system. We present an architecture, which allows third-party integration of software apps to interface with the virtual manufacturing machines. We evaluate our database schema against query statements and provide examples of how third-party apps can interface with manufacturing machines using the VMM middleware. Finally, we discuss an operating system architecture for VMMs across the manufacturing cyberspace, which necessitates command and control of various virtualized manufacturing machines, opening new possibilities in cyber-physical systems in manufacturing.}, journal={Journal of Manufacturing Systems}, publisher={Elsevier BV}, author={Angrish, Atin and Starly, Binil and Lee, Yuan-Shin and Cohen, Paul H.}, year={2017}, month={Oct}, pages={236–247} }
 @article{nordberg_zhang_griffith_frank_starly_loboa_2017, title={Electrical Cell-Substrate Impedance Spectroscopy Can Monitor Age-Grouped Human Adipose Stem Cell Variability During Osteogenic Differentiation}, volume={6}, ISSN={["2157-6580"]}, DOI={10.5966/sctm.2015-0404}, abstractNote={Human adipose stem cells (hASCs) are an attractive cell source for bone tissue engineering applications. However, a critical issue to be addressed before widespread hASC clinical translation is the dramatic variability in proliferative capacity and osteogenic potential among hASCs isolated from different donors. The goal of this study was to test our hypothesis that electrical cell‐substrate impedance spectroscopy (ECIS) could track complex bioimpedance patterns of hASCs throughout proliferation and osteogenic differentiation to better understand and predict variability among hASC populations. Superlots composed of hASCs from young (aged 24–36 years), middle‐aged (aged 48–55 years), and elderly (aged 60–81 years) donors were seeded on gold electrode arrays. Complex impedance measurements were taken throughout proliferation and osteogenic differentiation. During osteogenic differentiation, four impedance phases were identified: increase, primary stabilization, drop phase, and secondary stabilization. Matrix deposition was first observed 48–96 hours after the impedance maximum, indicating, for the first time, that ECIS can identify morphological changes that correspond to late‐stage osteogenic differentiation. The impedance maximum was observed at day 10.0 in young, day 6.1 in middle‐aged, and day 1.3 in elderly hASCs, suggesting that hASCs from younger donors require a longer time to differentiate than do hASCs from older donors, but young hASCs proliferated more and accreted more calcium long‐term. This is the first study to use ECIS to predict osteogenic potential of multiple hASC populations and to show that donor age may temporally control onset of osteogenesis. These findings could be critical for development of patient‐specific bone tissue engineering and regenerative medicine therapies. Stem Cells Translational Medicine 2017;6:502–511}, number={2}, journal={STEM CELLS TRANSLATIONAL MEDICINE}, author={Nordberg, Rachel C. and Zhang, Jianlei and Griffith, Emily H. and Frank, Matthew W. and Starly, Binil and Loboa, Elizabeth G.}, year={2017}, month={Feb}, pages={502–511} }
 @article{kumar_lau_starly_2017, title={Human Mesenchymal Stem Cells Expansion on Three-Dimensional (3D) Printed Poly-Styrene (PS) Scaffolds in a Perfusion Bioreactor}, volume={65}, ISSN={["2212-8271"]}, DOI={10.1016/j.procir.2017.04.012}, abstractNote={In this study, we present a novel approach of expanding Adipose derived hMSCs (human Mesenchymal Stem Cells) seeded on 3D printed Poly-Styrene (PS) scaffolds within a perfusion based cell expansion bioreactor. 3D printed PS scaffolds inoculated with adipose derived hMSCs were cultured statically for 9 days in 2D for assuring the viability and proliferation expansion of hMSCs on PS scaffolds. Thereafter, a batch of pre-seeded scaffolds were dynamically cultured inside a perfusion based bioreactor system for 8 days to assess the expansion of hMSCs on the PS scaffolds. As compared to static 3D culture (control), the 3D perfusion based system resulted in comparable fold-expansion and viability. Osteogenic and Adipogenic differentiation potential of the harvested cells were evaluated to assess if the stem cells retained their stem cell properties at the end of the expansion step.}, journal={3RD CIRP CONFERENCE ON BIOMANUFACTURING}, author={Kumar, Arun and Lau, Wing and Starly, Binil}, year={2017}, pages={115–120} }
 @inproceedings{narayanan_thompson_bhat_starly_shirwaiker_2017, title={Investigating dielectric impedance spectroscopy as a non-destructive quality assessment tool for 3D cellular constructs}, DOI={10.1115/msec2017-2725}, abstractNote={In any three dimensional (3D) biofabrication process, assessing critical biological quality attributes of 3D constructs such as viable cell number, cell distribution and metabolic activity is critical to determine the suitability and success of the process. One major limitation in current state-of-the-art is the lack of appropriate methods to monitor these quality attributes in situ in a non-destructive, label-free manner. In this study, we investigate the feasibility of using dielectric impedance spectroscopy to address this gap. We first measured the relative permittivity of 3D alginate constructs with four different concentrations of encapsulated MG63 cells (1–6.5 million cells/mL) and found them to be statistically significantly different (p < 0.05). Within the tested range, the relationship between cell concentration and relative permittivity was noted to be linear (R2 = 0.986). Furthermore, we characterized the β-dispersion parameters for MG63-encapsulated in alginate (6.5 million cells/mL). These results demonstrate that dielectric impedance spectroscopy can be used to monitor critical quality attributes of cell-encapsulated 3D constructs. Owing to the measurement efficiency and non-destructive mode of testing, this method has tremendous potential as an in-process quality control tool for 3D biofabrication processes and the long-term monitoring of cell-encapsulated 3D constructs.}, booktitle={Proceedings of the ASME 12th International Manufacturing Science and Engineering Conference - 2017, vol 4}, author={Narayanan, L. K. and Thompson, T. L. and Bhat, A. and Starly, Binil and Shirwaiker, Rohan}, year={2017} }
 @article{zhang_starly_cai_cohen_lee_2017, title={Particle learning in online tool wear diagnosis and prognosis}, volume={28}, ISSN={["1526-6125"]}, DOI={10.1016/j.jmapro.2017.04.012}, abstractNote={Automated Tool condition monitoring is critical in intelligent manufacturing to improve both productivity and sustainability of manufacturing operations. Estimation of tool wear in real-time for critical machining operations can improve part quality and reduce scrap rates. This paper proposes a probabilistic method based on a Particle Learning (PL) approach by building a linear system transition function whose parameters are updated through online in-process observations of the machining process. By applying PL, the method helps to avoid developing a complex closed form formulation for a specific tool wear model. It increases the robustness of the algorithm and reduces the time complexity of computation. The application of the PL approach is tested using experiments performed on a milling machine. We have demonstrated one-step and two-step look ahead tool wear state prediction using online indirect measurements obtained from vibration signals. Additionally, the study also estimates remaining useful life (RUL) of the cutting tool inserts.}, journal={JOURNAL OF MANUFACTURING PROCESSES}, author={Zhang, Jianlei and Starly, Binil and Cai, Yi and Cohen, Paul H. and Lee, Yuan-Shin}, year={2017}, month={Aug}, pages={457–463} }
 @article{cai_starly_cohen_lee_2017, title={Sensor Data and Information Fusion to Construct Digital-twins Virtual Machine Tools for Cyber-physical Manufacturing}, volume={10}, ISSN={2351-9789}, url={http://dx.doi.org/10.1016/J.PROMFG.2017.07.094}, DOI={10.1016/J.PROMFG.2017.07.094}, abstractNote={This paper presents sensor data integration and information fusion to build “digital-twins” virtual machine tools for cyber-physical manufacturing. Virtual machine tools are useful for simulating machine tools’ capabilities in a safe and cost-effective way, but it is challenging to accurately emulate the behavior of the physical tools. When a physical machine tool breaks down or malfunctions, engineers can always go back to check the digital traces of the “digital-twins” virtual machine for diagnosis and prognosis. This paper presents an integration of manufacturing data and sensory data into developing “digital-twins” virtual machine tools to improve their accountability and capabilities for cyber-physical manufacturing. The sensory data are used to extract the machining characteristics profiles of a digital-twins machine tool, with which the tool can better reflect the actual status of its physical counterpart in its various applications. In this paper, techniques are discussed for deploying sensors to capture machine-specific features, and analytical techniques of data and information fusion are presented for modeling and developing “digital-twins” virtual machine tools. Example of developing the digital-twins of a 3-axis vertical milling machine is presented to demonstrate the concept of modeling and building a digital-twins virtual machine tool for cyber-physical manufacturing. The presented technique can be used as a building block for cyber-physic manufacturing development.}, journal={Procedia Manufacturing}, publisher={Elsevier BV}, author={Cai, Yi and Starly, Binil and Cohen, Paul and Lee, Yuan-Shin}, year={2017}, pages={1031–1042} }
 @article{singh_angrish_barkley_starly_lee_cohen_2017, title={Streaming Machine Generated Data to Enable a Third-Party Ecosystem of Digital Manufacturing Apps}, volume={10}, ISSN={2351-9789}, url={http://dx.doi.org/10.1016/J.PROMFG.2017.07.093}, DOI={10.1016/J.PROMFG.2017.07.093}, abstractNote={The digital factory of the future will be driven by the integration of physical smart machine tools and cyber-enabled software, working seamlessly to increase manufacturing intelligence, flexibility, agility and production efficiency. The objective of this study is develop and demonstrate a middleware software architecture to interface physical machines on a shop floor with client manufacturing applications. We have connected both legacy and modern ‘smart’ machines to a highly scalable database capable of storing streaming time-series data generated by on-board sensors and machine controllers. Three client applications were developed to demonstrate the mechanism through which third-party apps can be written without direct physical communications with machines on the shop-floor. The first, is an application that resides within the Digital Manufacturing Commons (DMC) which demonstrates the ability to query data from any physical machine on the floor; the 2nd application demonstrates a python app which compares digital product data with machine generated data; and the 3rd application demonstrates building a LabView app built to interface with the middleware service. This proposed architecture enables an ecosystem of smart manufacturing applications to be built and deployed on the shop-floor through open-sourced software and hardware devices thereby reducing cost of manufacturing software development.}, journal={Procedia Manufacturing}, publisher={Elsevier BV}, author={Singh, Shaurabh and Angrish, Atin and Barkley, James and Starly, Binil and Lee, Yuan-Shin and Cohen, Paul}, year={2017}, pages={1020–1030} }
 @article{narayanan_huebner_fisher_spang_starly_shirwaiker_2016, title={3D-Bioprinting of Polylactic Acid (PLA) Nanofiber–Alginate Hydrogel Bioink Containing Human Adipose-Derived Stem Cells}, volume={2}, ISSN={2373-9878 2373-9878}, url={http://dx.doi.org/10.1021/ACSBIOMATERIALS.6B00196}, DOI={10.1021/acsbiomaterials.6b00196}, abstractNote={Bioinks play a central role in 3D-bioprinting by providing the supporting environment within which encapsulated cells can endure the stresses encountered during the digitally driven fabrication process and continue to mature, proliferate, and eventually form extracellular matrix (ECM). In order to be most effective, it is important that bioprinted constructs recapitulate the native tissue milieu as closely as possible. As such, musculoskeletal soft tissue constructs can benefit from bioinks that mimic their nanofibrous matrix constitution, which is also critical to their function. This study focuses on the development and proof-of-concept assessment of a fibrous bioink composed of alginate hydrogel, polylactic acid nanofibers, and human adipose-derived stem cells (hASC) for bioprinting such tissue constructs. First, hASC proliferation and viability were assessed in 3D-bioplotted strands over 16 days in vitro. Then, a human medial knee meniscus digitally modeled using magnetic resonance images was bioprinted and evaluated over 8 weeks in vitro. Results show that the nanofiber-reinforced bioink allowed higher levels of cell proliferation within bioprinted strands, with a peak at day 7, while still maintaining a vast majority of viable cells at day 16. The cell metabolic activity on day 7 was 28.5% higher in this bioink compared to the bioink without nanofibers. Histology of the bioprinted meniscus at both 4 and 8 weeks showed 54% and 147% higher cell density, respectively, in external versus internal regions of the construct. The presence of collagen and proteoglycans was also noted in areas surrounding the hASC, indicating ECM secretion and chondrogenic differentiation.}, number={10}, journal={ACS Biomaterials Science & Engineering}, publisher={American Chemical Society (ACS)}, author={Narayanan, Lokesh Karthik and Huebner, Pedro and Fisher, Matthew B. and Spang, Jeffrey T. and Starly, Binil and Shirwaiker, Rohan A.}, year={2016}, month={Jul}, pages={1732–1742} }
 @article{yasar_starly_2016, title={Fabrication of Lindenmayer System-Based Designed Engineered Scaffolds Using UV-Maskless Photolithography}, volume={1}, ISSN={["2059-8521"]}, DOI={10.1557/adv.2016.223}, abstractNote={In the field of tissue engineering, design and fabrication of precisely and spatially patterned, highly porous scaffolds/matrixes are required to guide overall shape of tissue growth and replacement. Although rapid prototyping fabrication techniques have been used to fabricate the scaffolds with desired design characteristics, controlling the interior architecture of the scaffolds has been a challenge due to Computer-aided Design (CAD) constrains. Moreover, thick engineered tissue scaffolds show inadequate success due to the limited diffusion of oxygen and nutrients to the interior part of the scaffolds. These limitations lead to improper tissue regeneration. In this work, in order to overcome these design and fabrication limitations, research has been expanded to generation of scaffolds which have inbuilt micro and nanoscale fluidic channels. Branching channels serve as material delivery paths to provide oxygen and nutrients for the cells. These channels are designed and controlled with Lindenmayer Systems (L-Systems) which is an influential way to create the complex branching networks by rewriting process. In this research, through the computational modeling process, to control the thickness, length, number and the position of the channels/branches, main attributes of L-Systems algorithms are characterized and effects of algorithm parameters are investigated. After the L-System based branching design is completed, 3D tissue scaffolds were fabricated by “UV-Maskless Photolithography”. In this fabrication technique, Polyethylene (glycol) Diacrylate (PEGDA), which is biodegradable and biocompatible polymer, was used as a fabrication material. Our results show that L-System parameters can be successfully controlled to designof 3D tissue engineered scaffolds. Our fabrication results also show that L-System based designed scaffolds with internal branch structures can be fabricated layer-by-layer fashion by Maskless Photolithography. This technology can be easily applied to engineering living systems.}, number={11}, journal={MRS ADVANCES}, author={Yasar, Ozlem and Starly, Binil}, year={2016}, pages={749–754} }
 @inproceedings{kumar_starly_2016, title={Modeling human mesenchymal stem cell expansion in vertical wheel bioreactors using lactate production rate in regenerative medicine biomanufacturing}, DOI={10.1115/msec2016-8787}, abstractNote={Stem cells are critical components of regenerative medicine therapy. However, the therapy will require millions to billions of therapeutic stem cells. To address the need, we have recently cultured stem cells in 3D microgels and used them as a vehicle for cell expansion within a low shear stress rotating wheel type bioreactor within a 500ml volumetric setting. This study specifically highlights the cell encapsulation in microbead process, harvesting and operation of microbeads within a dynamic bioreactor environment. We have specifically encapsulated stem cells (human adipose derived) into microbeads prepared from alginate hydrogels via an electrostatic jetting process. This study highlights the effect of fabrication process parameters on end-point biological quality measures such as stem cell count and viability. We were able to maintain a >80% viability during the 21 day static culture period. We have also measured the concentration of metabolites produced during the expansion, specifically lactate production measured during specific time points within culture inside the rotating wheel bioreactor Future work will need to address predicting yields in higher volume settings, efficiency of harvest and a more detailed description of the hydrodynamics affecting stem cell growth.}, booktitle={Proceedings of the ASME 11th International Manufacturing Science and Engineering Conference, 2016, vol 2}, author={Kumar, A. and Starly, Binil}, year={2016} }
 @article{narayanan_kumar_tan_bernacki_starly_shirwaiker_2015, title={Alginate Microspheroid Encapsulation and Delivery of MG-63 Cells Into Polycaprolactone Scaffolds: A New Biofabrication Approach for Tissue Engineering Constructs}, volume={6}, ISSN={1949-2944 1949-2952}, url={http://dx.doi.org/10.1115/1.4031174}, DOI={10.1115/1.4031174}, abstractNote={Scaffolds play an important role in tissue engineering by providing structural framework and a surface for cells to attach, proliferate, and secrete extracellular matrix (ECM). In order to enable efficient tissue formation, delivering sufficient cells into the scaffold three-dimensional (3D) matrix using traditional static and dynamic seeding methods continues to be a critical challenge. In this study, we investigate a new cell delivery approach utilizing deposition of hydrogel-cell encapsulated microspheroids into polycaprolactone (PCL) scaffolds to improve the seeding efficiency. Three-dimensional-bioplotted PCL constructs (0 deg/90 deg lay down, 284 ± 6 μm strand width, and 555 ± 8 μm strand separation) inoculated with MG-63 model bone cells encapsulated within electrostatically generated calcium-alginate microspheroids (O 405 ± 13 μm) were evaluated over seven days in static culture. The microspheroids were observed to be uniformly distributed throughout the PCL scaffold cross section. Encapsulated cells remained viable within the constructs over the test interval with the highest proliferation noted at day 4. This study demonstrates the feasibility of the new approach and highlights the role and critical challenges to be addressed to successfully utilize 3D-bioprinting for microencapsulated cell delivery.}, number={2}, journal={Journal of Nanotechnology in Engineering and Medicine}, publisher={ASME International}, author={Narayanan, Lokesh K. and Kumar, Arun and Tan, Zhuo (George) and Bernacki, Susan and Starly, Binil and Shirwaiker, Rohan A.}, year={2015}, month={May} }
 @article{dreher_starly_2015, title={Biofabrication of Multimaterial Three-Dimensional Constructs Embedded With Patterned Alginate Strands Encapsulating PC12 Neural Cell Lines}, volume={6}, ISSN={1949-2944 1949-2952}, url={http://dx.doi.org/10.1115/1.4031173}, DOI={10.1115/1.4031173}, abstractNote={In this study, we report the bioprinting of a three-dimensional (3D) heterogeneous conduit structure encapsulating PC12 neural cells. A core–shell-based hybrid construct is fabricated by combining electrospinning, polymer extrusion, and cell-based bioprinting processes to create a multiscale and multimaterial conduit structure. PC12 nerve cells were shown to be printed with high cell viability (>95%) and to proliferate within the rolled construct at a rate consistent with traditional two-dimensional (2D) culture. Light microscopy and scanning electron microscopy (SEM) have also shown encapsulation of cells within the printed alginate gel and an even cell distribution throughout the heterogeneous cellular construct.}, number={2}, journal={Journal of Nanotechnology in Engineering and Medicine}, publisher={ASME International}, author={Dreher, Rachel and Starly, Binil}, year={2015}, month={May} }
 @article{kumar_starly_2015, title={Large scale industrialized cell expansion: producing the critical raw material for biofabrication processes}, volume={7}, ISSN={["1758-5090"]}, DOI={10.1088/1758-5090/7/4/044103}, abstractNote={Cellular biomanufacturing technologies are a critical link to the successful application of cell and scaffold based regenerative therapies, organs-on-chip devices, disease models and any products with living cells contained in them. How do we achieve production level quantities of the key ingredient—‘the living cells’ for all biofabrication processes, including bioprinting and biopatterning? We review key cell expansion based bioreactor operating principles and how 3D culture will play an important role in achieving production quantities of billions to even trillions of anchorage dependent cells. Furthermore, we highlight some of the challenges in the field of cellular biomanufacturing that must be addressed to achieve desired cellular yields while adhering to the key pillars of good manufacturing practices—safety, purity, stability, potency and identity. Biofabrication technologies are uniquely positioned to provide improved 3D culture surfaces for the industrialized production of living cells.}, number={4}, journal={BIOFABRICATION}, author={Kumar, Arun and Starly, Binil}, year={2015}, month={Dec} }
 @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={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{khandaker_vaughan_starly_2014, title={The Influence of MgO Nanoparticles on the Osseointegration of Polycaprolactone - Sodium Alginate Hydrogel Interfaces}, volume={4}, ISSN={2231-0843}, url={http://dx.doi.org/10.9734/bjast/2014/5404}, DOI={10.9734/bjast/2014/5404}, abstractNote={This work was carried out in collaboration between all authors. Authors MK and BS designed the study and supervised the experiments. Author MBV directed the absorbance test study. Author MK wrote the first draft of the manuscript. All authors read and approved the final manuscript. ABSTRACT Aims: The aims of this study were to evaluate the influence of magnesium oxide (MgO) nanoparticles on the cell viability of a sodium alginate (SA) hydrogel and to evaluate the influence of MgO nanoparticles on the interface tensile strength between polycaprolactone (PCL) and SA hydrogel scaffolds after two weeks of cell culture. Study Design: Mouse osteoblast cells (MT3T3E1) were cultured on two groups of scaffolds: SA hydrogel and SA hydrogel with 22 nm MgO particles. Quantitative cell viability tests were conducted on each of the samples to compare the influence of magnesium oxide (MgO) nanoparticles on cell viability between the two groups. MT3T3E1 cells were cultured on two groups of coupled PCL-SA hydrogel scaffolds: PCL-SA hydrogel scaffold and PCL-SA hydrogel scaffold with 22 nm MgO particles. Tension tests were conducted on the coupled samples to compare the interface tensile strength between the two groups. Laboratory at the University of Central Oklahoma between June 2009 and May 2011. Methodology: Standard cell culture protocols were used to culture cells on SA hydrogel scaffolds with and without MgO nanoparticles for 4 and 24 hours. Absorbance and fluorescent intensity tests were conducted for quantitative measurements of cell viability. Cells were cultured on PCL-SA coupled scaffolds for 2 weeks. A custom tension setup was designed and fabricated to conduct tension tests on the coupled scaffolds to quantify the mechanical strength of the osseointegration. Results: This research found that SA hydrogel scaffolds containing MgO nanoparticles demonstrated higher osteoblast cell activity compared to SA hydrogel without MgO. The study also found reduced interface tensile strength when PCL-SA coupled scaffolds contained MgO nanoparticles. Conclusion: This study thus suggested that MgO nanoparticle improves the cell viability of SA hydrogel, but it is detrimental for the osseointegration of PCL-SA hydrogel constructs.}, number={1}, journal={British Journal of Applied Science & Technology}, publisher={Sciencedomain International}, author={Khandaker, M. and Vaughan, M. and Starly, B.}, editor={Vimalan, MEditor}, year={2014}, month={Jan}, pages={79–88} }
 @article{lan_kehinde_zhang_khajotia_schmidtke_starly_2013, title={Controlled release of metronidazole from composite poly-ε-caprolactone/alginate (PCL/alginate) rings for dental implants}, volume={29}, ISSN={0109-5641}, url={http://dx.doi.org/10.1016/j.dental.2013.03.014}, DOI={10.1016/j.dental.2013.03.014}, abstractNote={Dental implants provide support for dental crowns and bridges by serving as abutments for the replacement of missing teeth. To prevent bacterial accumulation and growth at the site of implantation, solutions such as systemic antibiotics and localized delivery of bactericidal agents are often employed. The objective of this study was to demonstrate a novel method of controlled localized delivery of antibacterial agents to an implant site using a biodegradable custom fabricated ring. The study involved incorporating a model antibacterial agent (metronidazole) into custom designed poly-ε-caprolactone/alginate (PCL/alginate) composite rings to produce the intended controlled release profile. The rings can be designed to fit around the body of any root form dental implants of various diameters, shapes and sizes. In vitro release studies indicate that pure (100%) alginate rings exhibited an expected burst release of metronidazole in the first few hours, whereas Alginate/PCL composite rings produced a medium burst release followed by a sustained release for a period greater than 4 weeks. By varying the PCL/alginate weight ratios, we have shown that we can control the amount of antibacterial agents released to provide the minimal inhibitory concentration (MIC) needed for adequate protection. The fabricated composite rings have achieved a 50% antibacterial agent release profile over the first 48 h and the remaining amount slowly released over the remainder of the study period. The PCL/alginate agent release characteristic fits the Ritger–Peppas model indicating a diffusion-based mechanism during the 30-day study period. The developed system demonstrates a controllable drug release profile and the potential for the ring to inhibit bacterial biofilm growth for the prevention of diseases such as peri-implantitis resulting from bacterial infection at the implant site.}, number={6}, journal={Dental Materials}, publisher={Elsevier BV}, author={Lan, Shih-Feng and Kehinde, Timilehin and Zhang, Xiangming and Khajotia, Sharukh and Schmidtke, David W. and Starly, Binil}, year={2013}, month={Jun}, pages={656–665} }
 @article{parthasarathy_starly_raman_2011, title={A design for the additive manufacture of functionally graded porous structures with tailored mechanical properties for biomedical applications}, volume={13}, ISSN={1526-6125}, url={http://dx.doi.org/10.1016/j.jmapro.2011.01.004}, DOI={10.1016/j.jmapro.2011.01.004}, abstractNote={CAD/CAM-based layered manufacturing and additive manufacturing techniques of metals have found applications in near-net-shape fabrication of complex shaped parts with tailored mechanical properties for several applications. Especially with the onset of newer processes such as electron beam melting (EBM) and direct metal laser sintering (DMLS), revolutionary advances may be achieved in material substitution in the medical implant industry. These processes must be suitably developed and tested for the production of medical grade substitutions. In this article, we discuss a design process for creating periodic cellular structures specifically targeted for biomedical applications. Electron beam melting is used to fabricate the parts. Evaluation of the mechanical properties is performed and compared with design parameters. Compression tests of the samples show effective stiffness values ranging from 0.57 (±0.05) to 2.92 (±0.17) GPa and compressive strength values of 7.28 (±0.93) to 163.02 (±11.98) MPa. Substituting these values for simulation of biomechanical performance of patient-specific implants illustrates the compatibility and matched functional performance characteristics of highly porous parts at a safety factor of 5 and an effective reduction in weight. These developments are unique for the construction of maxillofacial and craniofacial implants. The novel design strategy also lends itself very well to metal additive manufacturing technologies. Implants designed and fabricated with this design strategy and manufacturing process would have mechanical properties equivalent to the part they replace and restore better function and esthetics as against the currently used methods of reconstruction. Suitable examples of a titanium porous cranioplasty plate and a sandwich structure are illustrated.}, number={2}, journal={Journal of Manufacturing Processes}, publisher={Elsevier BV}, author={Parthasarathy, Jayanthi and Starly, Binil and Raman, Shivakumar}, year={2011}, month={Aug}, pages={160–170} }
 @article{lan_starly_2011, title={Alginate based 3D hydrogels as an in vitro co-culture model platform for the toxicity screening of new chemical entities}, volume={256}, ISSN={0041-008X}, url={http://dx.doi.org/10.1016/j.taap.2011.07.013}, DOI={10.1016/j.taap.2011.07.013}, abstractNote={Prediction of human response to potential therapeutic drugs is through conventional methods of in vitro cell culture assays and expensive in vivo animal testing. Alternatives to animal testing require sophisticated in vitro model systems that must replicate in vivo like function for reliable testing applications. Advancements in biomaterials have enabled the development of three-dimensional (3D) cell encapsulated hydrogels as in vitro drug screening tissue model systems. In this study, we have developed an in vitro platform to enable high density 3D culture of liver cells combined with a monolayer growth of target breast cancer cell line (MCF-7) in a static environment as a representative example of screening drug compounds for hepatotoxicity and drug efficacy. Alginate hydrogels encapsulated with serial cell densities of HepG2 cells (105–108 cells/ml) are supported by a porous poly-carbonate disc platform and co-cultured with MCF-7 cells within standard cell culture plates during a 3 day study period. The clearance rates of drug transformation by HepG2 cells are measured using a coumarin based pro-drug. The platform was used to test for HepG2 cytotoxicity 50% (CT50) using commercially available drugs which further correlated well with published in vivo LD50 values. The developed test platform allowed us to evaluate drug dose concentrations to predict hepatotoxicity and its effect on the target cells. The in vitro 3D co-culture platform provides a scalable and flexible approach to test multiple-cell types in a hybrid setting within standard cell culture plates which may open up novel 3D in vitro culture techniques to screen new chemical entity compounds.}, number={1}, journal={Toxicology and Applied Pharmacology}, publisher={Elsevier BV}, author={Lan, Shih-Feng and Starly, Binil}, year={2011}, month={Oct}, pages={62–72} }
 @article{padmanabhan_kamaraj_magwood_starly_2011, title={Experimental investigation on the operating variables of a near-field electrospinning process via response surface methodology}, volume={13}, ISSN={1526-6125}, url={http://dx.doi.org/10.1016/j.jmapro.2011.01.003}, DOI={10.1016/j.jmapro.2011.01.003}, abstractNote={The past decade has seen tremendous advances in producing nanofibers and nanowires from a variety of materials for applications in sensors, photovoltaic devices and regenerative medicine. Nano and sub-micron fibers produced from a conventional electrospinning process are relatively inexpensive to produce but result in entangled and randomly oriented fibers. In this research, we have utilized a modified form of the electrospinning process, wherein polymeric fibers of Poly-caprolactone (PCL) are deposited in controlled pattern orientations by the ‘near-field electrospinning’ process. The process variables are interdependent and greatly influence the final deposition and diameters of the fibers. Response Surface Methodology (RSM) was used to obtain a quantitative and systematic understanding of the near-field deposition process and its relationship with the process parameters. A response surface function was empirically determined with fiber diameter as the observed response and the deposition parameters as the variables. Fibers of diameter ranging for 500–1500 nm were produced with a reasonable R2 value of 0.74, which indicates approximately seventy five percent of the variation in the response variable can be explained by the explanatory variables and the rest by the inherent process variability.}, number={2}, journal={Journal of Manufacturing Processes}, publisher={Elsevier BV}, author={Padmanabhan, Thirumalpathy and Kamaraj, Vivekanand and Magwood, Leroy, Jr. and Starly, Binil}, year={2011}, month={Aug}, pages={104–112} }
 @article{charles_raman_starly_2011, title={Sustainment: A Growth Industry for Custom Manufacturing in the United States}, volume={1}, number={1}, journal={Journal of Aviation and Aerospace Perspectives}, author={Charles, Ryan and Raman, Shivakumar and Starly, Binil}, year={2011}, pages={5–16} }
 @article{davies_starly_2011, title={Virtual and Real: Using 3D Scanning, Modeling and Printing in Reconstructing a Juvenile Apatosaurus Skeleton}, volume={31}, number={Supplement 2}, journal={Journal of Vertebrate Paleontology}, author={Davies, K. and Starly, B.}, year={2011} }
 @article{lan_safiejko-mroczka_starly_2010, title={Long-term cultivation of HepG2 liver cells encapsulated in alginate hydrogels: A study of cell viability, morphology and drug metabolism}, volume={24}, ISSN={0887-2333}, url={http://dx.doi.org/10.1016/j.tiv.2010.02.015}, DOI={10.1016/j.tiv.2010.02.015}, abstractNote={In this study, we have evaluated the use of ultra-sterile alginate hydrogels encapsulated with HepG2 liver cells for applications in high throughput drug screening. We have studied the cellular viability and metabolic capacity of the encapsulated cells in two different alginate structures SLM100 (G:M::40:60) and SLG100 (G:M::60:40). We have also developed protocols to characterize the encapsulated cells within the alginate structure using scanning electron microscopy (SEM) and laser scanning confocal microscopy (LSCM). Further we have studied the Phase-I/II metabolic characteristics of the encapsulated cells in monolayer and 3D culture. Our results indicate that cells encapsulated within SLM100 and SLG100 class of alginates have shown high cellular viability with >80% even after 14 days in culture. As expected, the proliferation rates of the encapsulated cells are held steady and do not proliferate within the gels. Production of liver-specific enzymes such as CYP1A1 and CYP3A4 after 14 days in culture indicates the viability and functionality of the encapsulated HepG2 cells. Phase-II Glutathione activity of the encapsulated cells were also maintained in 3D culture conditions. The encapsulated cells within the 3D gels were also capable of metabolizing the pro-drug EFC (7-ethoxy-4-trifluoromethyl coumarin) to HFC (7-hydroxy-4-trifluoromethyl) in a linear fashion over a period of time. These results have provided us with baseline results to benchmark future improvements in material and design configurations for optimal pharmacokinetic response of in vitro tissue model systems.}, number={4}, journal={Toxicology in Vitro}, publisher={Elsevier BV}, author={Lan, Shih-Feng and Safiejko-Mroczka, Barbara and Starly, Binil}, year={2010}, month={Jun}, pages={1314–1323} }
 @article{parthasarathy_starly_raman_christensen_2010, title={Mechanical evaluation of porous titanium (Ti6Al4V) structures with electron beam melting (EBM)}, volume={3}, ISSN={1751-6161}, url={http://dx.doi.org/10.1016/j.jmbbm.2009.10.006}, DOI={10.1016/j.jmbbm.2009.10.006}, abstractNote={Patient specific porous implants for the reconstruction of craniofacial defects have gained importance due to their better performance over their generic counterparts. The recent introduction of electron beam melting (EBM) for the processing of titanium has led to a one step fabrication of porous custom titanium implants with controlled porosity to meet the requirements of the anatomy and functions at the region of implantation. This paper discusses an image based micro-structural analysis and the mechanical characterization of porous Ti6Al4V structures fabricated using the EBM rapid manufacturing process. SEM studies have indicated the complete melting of the powder material with no evidence of poor inter-layer bonding. Micro-CT scan analysis of the samples indicate well formed titanium struts and fully interconnected pores with porosities varying from 49.75%–70.32%. Compression tests of the samples showed effective stiffness values ranging from 0.57(±0.05)−2.92(±0.17)GPa and compressive strength values of 7.28(±0.93)−163.02(±11.98)MPa. For nearly the same porosity values of 49.75% and 50.75%, with a variation in only the strut thickness in the sample sets, the compressive stiffness and strength decreased significantly from 2.92 GPa to 0.57 GPa (80.5% reduction) and 163.02 MPa to 7.28 MPa (93.54 % reduction) respectively. The grain density of the fabricated Ti6Al4V structures was found to be 4.423 g/cm3 equivalent to that of dense Ti6Al4V parts fabricated using conventional methods. In conclusion, from a mechanical strength viewpoint, we have found that the porous structures produced by the electron beam melting process present a promising rapid manufacturing process for the direct fabrication of customized titanium implants for enabling personalized medicine.}, number={3}, journal={Journal of the Mechanical Behavior of Biomedical Materials}, publisher={Elsevier BV}, author={Parthasarathy, Jayanthi and Starly, Binil and Raman, Shivakumar and Christensen, Andy}, year={2010}, month={Apr}, pages={249–259} }
 @article{yasar_lan_starly_2009, title={A Lindenmayer system-based approach for the design of nutrient delivery networks in tissue constructs}, volume={1}, ISSN={1758-5082 1758-5090}, url={http://dx.doi.org/10.1088/1758-5082/1/4/045004}, DOI={10.1088/1758-5082/1/4/045004}, abstractNote={Large thick tissue constructs have reported limited success primarily due to the inability of cells to survive deep within the scaffold. Without access to adequate nutrients, cells placed deep within the tissue construct will die out, leading to non-uniform tissue regeneration. Currently, there is a necessity to design nutrient conduit networks within the tissue construct to enable cells to survive in the matrix. However, the design of complex networks within a tissue construct is challenging. In this paper, we present the Lindenmayer system, an elegant fractal-based language algorithm framework, to generate conduit networks in two- and three-dimensional architecture with several degrees of complexity. The conduit network maintains a parent–child relationship between each branch of the network. Several L-system parameters have been studied—branching angle, branch length, ratio of parent to child branch diameter, etc—to simulate several architectures under a given L-system notation. We have also presented a layered manufacturing-based UV-photopolymerization process using the Texas Instruments DLP™ system to fabricate the branched structures. This preliminary work showcases the applicability of L-system-based construct designs to drive scaffold fabrication systems.}, number={4}, journal={Biofabrication}, publisher={IOP Publishing}, author={Yasar, Ozlem and Lan, Shih-Feng and Starly, Binil}, year={2009}, month={Dec}, pages={045004} }
 @article{parthasarathy_starly_raman_2009, title={Computer Aided Biomodeling and Analysis of Patient Specific Porous Titanium Mandibular Implants}, volume={3}, ISSN={1932-6181 1932-619X}, url={http://dx.doi.org/10.1115/1.3192104}, DOI={10.1115/1.3192104}, abstractNote={Custom implants for the reconstruction of mandibular defects have recently gained importance due to their better performance over their generic counterparts. This is attributed to their precise adaptation to the region of implantation, reduced surgical times, and better cosmesis. Recent introduction of direct digital manufacturing technologies, which enable the fabrication of implants from patient specific data, has opened up a new horizon for the next generation of customized maxillofacial implants. In this article, we discuss a representative volume element based technique in which precisely defined porous implants with customized stiffness values are designed to match the stiffness and weight characteristics of surrounding healthy bone tissue. Dental abutment structures have been incorporated into the mandibular implant. Finite element analysis is used to assess the performance of the implant under masticatory loads. This design strategy lends itself very well to rapid manufacturing technologies based on metal sintering processes.}, number={3}, journal={Journal of Medical Devices}, publisher={ASME International}, author={Parthasarathy, Jayanthi and Starly, Binil and Raman, Shivakumar}, year={2009}, month={Sep} }
 @article{mishra_starly_2009, title={Real time in vitro measurement of oxygen uptake rates for HEPG2 liver cells encapsulated in alginate matrices}, volume={6}, ISSN={1613-4982 1613-4990}, url={http://dx.doi.org/10.1007/s10404-008-0396-z}, DOI={10.1007/s10404-008-0396-z}, number={3}, journal={Microfluidics and Nanofluidics}, publisher={Springer Science and Business Media LLC}, author={Mishra, Anuja and Starly, Binil}, year={2009}, month={Jan}, pages={373–381} }
 @article{starly_yildirim_sun_2007, title={A tracer metric numerical model for predicting tortuosity factors in three-dimensional porous tissue scaffolds}, volume={87}, ISSN={0169-2607}, url={http://dx.doi.org/10.1016/j.cmpb.2007.04.003}, DOI={10.1016/j.cmpb.2007.04.003}, abstractNote={One of the critical functions of a tissue-engineered construct is to be able to provide adequate nutrient and oxygen supply into the interior of the construct. An insufficient supply will lead to slower cellular proliferation rates and eventual apoptosis. The supply of the nutrients is largely governed by the transport properties of the construct which in turn is dependent on the porosity, tortuosity and surface chemistry of the tissue construct. The design and fabrication of scaffolds with tailored properties is thus a crucial step in the growth of tissue within their host environment. This paper discusses the development of a numerical characterization technique to measure the three-dimensional tortuosity factors for any given interconnected porous design. Tortuosity factors are obtained in the three orthogonal principal directions for several candidate unit cell architectures. The proposed numerical technique has been validated with models of known tortuosity. The developed technique will provide a basis for the study of transport properties of the designed scaffold and its effect on cellular function and response through the development of dynamic culture bioreactors.}, number={1}, journal={Computer Methods and Programs in Biomedicine}, publisher={Elsevier BV}, author={Starly, B. and Yildirim, E. and Sun, W.}, year={2007}, month={Jul}, pages={21–27} }
 @article{starly_choubey_2007, title={Enabling Sensor Technologies for the Quantitative Evaluation of Engineered Tissue}, volume={36}, ISSN={0090-6964 1573-9686}, url={http://dx.doi.org/10.1007/s10439-007-9399-2}, DOI={10.1007/s10439-007-9399-2}, number={1}, journal={Annals of Biomedical Engineering}, publisher={Springer Science and Business Media LLC}, author={Starly, Binil and Choubey, Anuja}, year={2007}, month={Oct}, pages={30–40} }
 @article{starly_sun_2007, title={Internal Scaffold Architecture Designs using Lindenmayer Systems}, volume={4}, ISSN={1686-4360}, url={http://dx.doi.org/10.1080/16864360.2007.10738559}, DOI={10.1080/16864360.2007.10738559}, abstractNote={AbstractScaffolds with designed interior pore architecture, predefined porosity and a well interconnected predetermined channel network has been the favored design approach for tissue engineering applications. Solid freeform fabrication (SFF) technologies have provided the capability to fabricate scaffolds with desired design characteristics due to its integration with CAD enabled tools. However, currently the interior macro pore design of scaffolds have been limited to simple regular shapes of either squares or circles due to inadequate CAD capability. In this paper we seek to enhance the design of the scaffold architecture by the use of rewriting schemas such as Lindenmayer systems (Lsystems) which provide a powerful method to create complex branched networks. We have presented several exploratory case examples to show the applicability of using such rewriting systems to model nutrient delivery networks within hydrogel scaffolds without an overwhelming need for expensive computer hardware. Feasibility s...}, number={1-4}, journal={Computer-Aided Design and Applications}, publisher={CAD Solutions, LLC}, author={Starly, Binil and Sun, Wei}, year={2007}, month={Jan}, pages={395–403} }
 @article{piatt_starly_sun_faerber_2006, title={Application of computer-assisted design in craniofacial reconstructive surgery using a commercial image guidance system}, volume={104}, ISSN={1933-0707}, url={http://dx.doi.org/10.3171/ped.2006.104.1.64}, DOI={10.3171/ped.2006.104.1.64}, abstractNote={The technology of digital image guidance systems has transformed many aspects of neurosurgery, including intracranial tumor surgery, functional neurosurgery, and spinal surgery. Despite the central role of imaging studies in diagnosis and treatment planning, intraoperative image guidance has so far had very limited application to the surgical correction of craniofacial deformities, particularly those associated with craniosynostosis. The authors report an example of the marriage of computer-assisted design methods to a commercially available neurosurgical image-guidance system in the treatment of a case of anterior plagiocephaly due to unilateral coronal synostosis. They discuss the steps that must yet be taken to make this technology applicable to the management of craniosynostosis in infants.}, number={1}, journal={Journal of Neurosurgery: Pediatrics}, publisher={Journal of Neurosurgery Publishing Group (JNSPG)}, author={Piatt, Joseph H., Jr. and Starly, Binil and Sun, Wei and Faerber, Eric}, year={2006}, month={Jan}, pages={64–67} }
 @article{evans_starly_sun_2006, title={Computer Aided Tissue Engineering for the Design and Evaluation of Lumbar-Spine Arthroplasty}, volume={3}, ISSN={1686-4360}, url={http://dx.doi.org/10.1080/16864360.2006.10738430}, DOI={10.1080/16864360.2006.10738430}, abstractNote={AbstractDegeneration of the intervertebral disc with age has been shown to be a significant source of pain and discomfort in the elderly, ultimately leading to a decreased functionality of the spine. Current treatments for disc degeneration focus on the fixation of the spinal unit by fusing the vertebra together, thus limiting and stabilizing the intervertebral motion, reducing the pain associated with the compression of the degenerated disc. Other treatments consist of entirely replacing the intervertebral disc, restoring function to the spine without reducing the range of motion. However, long term results of these treatments have been less than satisfactory, demanding a new approach to the treatment of degenerated intervertebral discs. The goal of this study was to develop a scaffold-like intervertebral disc with the mechanical characteristics required to function in the lumbar spine environment, thereby facilitating biological growth and eventual fixation of the disc within the spinal column.}, number={6}, journal={Computer-Aided Design and Applications}, publisher={CAD Solutions, LLC}, author={Evans, Peter J. and Starly, Binil and Sun, Wei}, year={2006}, month={Jan}, pages={771–778} }
 @article{starly_lau_bradbury_sun_2006, title={Internal architecture design and freeform fabrication of tissue replacement structures}, volume={38}, ISSN={0010-4485}, url={http://dx.doi.org/10.1016/j.cad.2005.08.001}, DOI={10.1016/j.cad.2005.08.001}, abstractNote={Modeling, design and fabrication of tissue scaffolds with intricate architecture, porosity and pore size for desired tissue properties presents a challenge in tissue engineering. This paper will present the details of our development in the design and fabrication of the interior architecture of scaffolds using a novel design approach. The interior architecture design (IAD) approach seeks to generate layered scaffold freeform fabrication tool path without forming complicated 3D CAD scaffold models. This involves: applying the principle of layered manufacturing to determine the scaffold individual layered process planes and layered contours; defining the 2D characteristic patterns of the scaffold building blocks (unit cells) to form the Interior Scaffold Pattern; and the generating the process tool path for freeform fabrication of these scaffolds with the specified interior architecture. Feasibility studies applying the IAD algorithm to example models with multi-interior architecture and the generation of fabrication planning instructions will also be presented.}, number={2}, journal={Computer-Aided Design}, publisher={Elsevier BV}, author={Starly, B. and Lau, W. and Bradbury, T. and Sun, W.}, year={2006}, month={Feb}, pages={115–124} }
 @article{fang_starly_shokoufandeh_regli_sun_2005, title={A Computer-aided Multi-scale Modeling and Direct Fabrication of Bone Structure}, volume={2}, ISSN={1686-4360}, url={http://dx.doi.org/10.1080/16864360.2005.10738327}, DOI={10.1080/16864360.2005.10738327}, abstractNote={A multi-scale voxel modeling approach was presented to model the bone structure both in macroscopic and microscopic level. Based on the digital image, the overall macroscopic geometry of the vertebrate was acquired by traditional reverse engineering technology and the microscopic random trabecular network was described by two-point correlation function and the function was then used to reconstruct the bone microstructure. It was shown that the reconstructed model is statistically equivalent to the original structure in the microscopic level and the design intension can be integrated in the developed model. A direct-fabrication process planning was also developed based on the voxel model. The advantage is that there is no need for slicing process in this process which is a costly and essential process for traditional rapid prototype technology.}, number={5}, journal={Computer-Aided Design and Applications}, publisher={CAD Solutions, LLC}, author={Fang, Zhibin and Starly, Binil and Shokoufandeh, Ali and Regli, William and Sun, Wei}, year={2005}, month={Jan}, pages={627–635} }
 @article{sun_starly_nam_darling_2005, title={Bio-CAD modeling and its applications in computer-aided tissue engineering}, volume={37}, ISSN={0010-4485}, url={http://dx.doi.org/10.1016/j.cad.2005.02.002}, DOI={10.1016/j.cad.2005.02.002}, abstractNote={CAD has been traditionally used to assist in engineering design and modeling for representation, analysis and manufacturing. Advances in Information Technology and in Biomedicine have created new uses for CAD with many novel and important biomedical applications, particularly tissue engineering in which CAD based bio-tissue informatics model provides critical information of tissue biological, biophysical, and biochemical properties for modeling, design, and fabrication of complex tissue substitutes. This paper will present some salient advances of bio-CAD modeling and application in computer-aided tissue engineering, including biomimetic design, analysis, simulation and freeform fabrication of tissue engineered substitutes. Overview of computer-aided tissue engineering will be given. Methodology to generate bio-CAD models from high resolution non-invasive imaging, the medical imaging process and the 3D reconstruction technique will be described. Enabling state-of-the-art computer software in assisting 3D reconstruction and in bio-modeling development will be introduced. Utilization of the bio-CAD model for the description and representation of the morphology, heterogeneity, and organizational structure of tissue anatomy, and the generation of bio-blueprint modeling will also be presented.}, number={11}, journal={Computer-Aided Design}, publisher={Elsevier BV}, author={Sun, W. and Starly, B. and Nam, J. and Darling, A.}, year={2005}, month={Sep}, pages={1097–1114} }
 @article{fang_starly_sun_2005, title={Computer-aided characterization for effective mechanical properties of porous tissue scaffolds}, volume={37}, ISSN={0010-4485}, url={http://dx.doi.org/10.1016/j.cad.2004.04.002}, DOI={10.1016/j.cad.2004.04.002}, abstractNote={Performance of various functions of the tissue structure depends on porous scaffold microstructures with specific porosity characteristics that influence the behavior of the incorporated or ingrown cells. Understanding the mechanical properties of porous tissue scaffold is important for its biological and biomechanical tissue engineering application. This paper presents a computer aided characterization approach to evaluate the effective mechanical properties of porous tissue scaffold. An outline of a computer-aided tissue engineering approach for design and fabrication of porous tissue scaffold, procedure of computer-aided characterization and its interface with design model, development of a computational algorithm for finite element implementation and numerical solution of asymptotic homogenization theory is presented. Application of the algorithm to characterize the effective mechanical properties of porous poly-ε-caprolactone scaffold manufactured by precision extruding freeform deposition will also be presented, along with a parametric study of the process and design parameter to the structural properties of tissue scaffold.}, number={1}, journal={Computer-Aided Design}, publisher={Elsevier BV}, author={Fang, Z. and Starly, B. and Sun, W.}, year={2005}, month={Jan}, pages={65–72} }
 @article{wettergreen_bucklen_starly_yuksel_sun_liebschner_2005, title={Creation of a unit block library of architectures for use in assembled scaffold engineering}, volume={37}, ISSN={0010-4485}, url={http://dx.doi.org/10.1016/j.cad.2005.02.005}, DOI={10.1016/j.cad.2005.02.005}, abstractNote={Guided tissue regeneration is gaining importance in the field of orthopaedic tissue engineering as need and technology permits the development of site-specific engineering approaches. Computer Aided Design (CAD) and Finite Element Analysis (FEA) hybridized with manufacturing techniques such as Solid Freeform Fabrication (SFF), is hypothesized to allow for virtual design, characterization, and production of scaffolds optimized for tissue replacement. However, a design scope this broad is not often realized due to limitations in preparing scaffolds both for biological functionality and mechanical longevity. To aid scientists in fabrication of a successful scaffold, we propose characterization and documentation of a library of micro-architectures, capable of being seamlessly merged according to the mechanical properties (stiffness, strength), flow perfusion characteristics, and porosity, determined by the scientist based on application and anatomic location. The methodology is discussed in the sphere of bone regeneration, and examples of catalogued shapes are presented. Similar principles may apply for other organs as well.}, number={11}, journal={Computer-Aided Design}, publisher={Elsevier BV}, author={Wettergreen, M.A. and Bucklen, B.S. and Starly, B. and Yuksel, E. and Sun, W. and Liebschner, M.A.K.}, year={2005}, month={Sep}, pages={1141–1149} }
 @article{starly_lau_sun_lau_bradbury_2005, title={Direct slicing of STEP based NURBS models for layered manufacturing}, volume={37}, ISSN={0010-4485}, url={http://dx.doi.org/10.1016/j.cad.2004.06.014}, DOI={10.1016/j.cad.2004.06.014}, abstractNote={Direct slicing of CAD models to generate process planning instructions for solid freeform fabrication may overcome inherent disadvantages of using stereolithography format in terms of the process accuracy, ease of file management, and incorporation of multiple materials. This paper will present the results of our development of a direct slicing algorithm for layered freeform fabrication. The direct slicing algorithm was based on a neutral, international standard (ISO 10303) STEP-formatted non-uniform rational B-spline (NURBS) geometric representation and is intended to be independent of any commercial CAD software. The following aspects of the development effort will be presented: (1) determination of optimal build direction based upon STEP-based NURBS models; (2) adaptive subdivision of NURBS data for geometric refinement; and (3) ray-casting slice generation into sets of raster patterns. The development also provides for multi-material slicing and will provide an effective tool in heterogeneous slicing processes.}, number={4}, journal={Computer-Aided Design}, publisher={Elsevier BV}, author={Starly, B. and Lau, A. and Sun, W. and Lau, W. and Bradbury, T.}, year={2005}, month={Apr}, pages={387–397} }
 @article{starly_fang_sun_shokoufandeh_regli_2005, title={Three-Dimensional Reconstruction for Medical-CAD Modeling}, volume={2}, ISSN={1686-4360}, url={http://dx.doi.org/10.1080/16864360.2005.10738392}, DOI={10.1080/16864360.2005.10738392}, abstractNote={AbstractCAD has been traditionally used to assist in engineering design and modeling for representation, analysis and manufacturing. Advances in Information Technology and in Biomedicine have created new uses for CAD with many novel and important biomedical applications, particularly in tissue engineering in which the CAD based bio-tissue informatics model provides critical information of tissue biological, biophysical, and biochemical properties for modeling, design, and fabrication of complex tissue substitutes. This paper will present some salient advances of bio-CAD modeling and application in computer-aided tissue engineering, including biomimetic design, analysis, simulation and freeform fabrication of tissue engineered substitutes. An overview of computer-aided tissue engineering will be given. Methodology to generate bio-CAD models from high resolution non-invasive imaging, the medical image process and the 3D reconstruction technique will be described. Enabling state-of-the-art computer programs ...}, number={1-4}, journal={Computer-Aided Design and Applications}, publisher={CAD Solutions, LLC}, author={Starly, B. and Fang, Z. and Sun, W. and Shokoufandeh, A. and Regli, W.}, year={2005}, month={Jan}, pages={431–438} }
 @article{nam_starly_darling_sun_2004, title={Computer Aided Tissue Engineering for Modeling and Design of Novel Tissue Scaffolds}, volume={1}, ISSN={1686-4360}, url={http://dx.doi.org/10.1080/16864360.2004.10738308}, DOI={10.1080/16864360.2004.10738308}, abstractNote={AbstractComputer-aided tissue engineering (CATE) integrates advances of multi-disciplinary fields of Biology, Biomedical Engineering, Information Technology, and modern Design and Manufacturing. Application of CATE to the design and fabrication of tissue scaffolds can facilitate the exploration of many novel ideas of incorporating biomimetic and biological features into the scaffold design. This paper presents some of the salient applications of CATE, particularly in the modeling and design of scaffolds with controlled internal and external architecture; with vascular channels of different sizes; with modular and interconnecting subunits; with multi-layered heterogeneous dense and compact regions; and the scaffolds with designed artificial chambers for drug delivery, embedded growth factors and other sophisticated features.}, number={1-4}, journal={Computer-Aided Design and Applications}, publisher={CAD Solutions, LLC}, author={Nam, J. and Starly, B. and Darling, A. and Sun, W.}, year={2004}, month={Jan}, pages={633–640} }
 @article{sun_starly_darling_gomez_2004, title={Computer-aided tissue engineering: application to biomimetic modelling and design of tissue scaffolds}, volume={39}, ISSN={0885-4513 1470-8744}, url={http://dx.doi.org/10.1042/ba20030109}, DOI={10.1042/ba20030109}, abstractNote={Computer‐aided tissue engineering (CATE) enables many novel approaches in modelling, design and fabrication of complex tissue substitutes with enhanced functionality and improved cell–matrix interactions. Central to CATE is its bio‐tissue informatics model that represents tissue biological, biomechanical and biochemical information that serves as a central repository to interface design, simulation and tissue fabrication. The present paper discusses the application of a CATE approach to the biomimetic design of bone tissue scaffold. A general CATE‐based process for biomimetic modelling, anatomic reconstruction, computer‐assisted‐design of tissue scaffold, quantitative‐computed‐tomography characterization, finite element analysis and freeform extruding deposition for fabrication of scaffold is presented.}, number={1}, journal={Biotechnology and Applied Biochemistry}, publisher={Wiley}, author={Sun, Wei and Starly, Binil and Darling, Andrew and Gomez, Connie}, year={2004}, month={Feb}, pages={49} }
 @article{sun_darling_starly_nam_2004, title={Computer-aided tissue engineering: overview, scope and challenges}, volume={39}, ISSN={0885-4513 1470-8744}, url={http://dx.doi.org/10.1042/ba20030108}, DOI={10.1042/ba20030108}, abstractNote={Advances in computer‐aided technology and its application with biology, engineering and information science to tissue engineering have evolved a new field of computer‐aided tissue engineering (CATE). This emerging field encompasses computer‐aided design (CAD), image processing, manufacturing and solid free‐form fabrication (SFF) for modelling, designing, simulation and manufacturing of biological tissue and organ substitutes. The present Review describes some salient advances in this field, particularly in computer‐aided tissue modeling, computer‐aided tissue informatics and computer‐aided tissue scaffold design and fabrication. Methodologies of development of CATE modelling from high‐resolution non‐invasive imaging and image‐based three‐dimensional reconstruction, and various reconstructive techniques for CAD‐based tissue modelling generation will be described. The latest development in SFF to tissue engineering and a framework of bio‐blueprint modelling for three‐dimensional cell and organ printing will also be introduced.}, number={1}, journal={Biotechnology and Applied Biochemistry}, publisher={Wiley}, author={Sun, Wei and Darling, Andrew and Starly, Binil and Nam, Jae}, year={2004}, month={Feb}, pages={29} }