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Akron, OH, United States

Davis S.A.,The Cooper Union for the Advancement of Science and Art | Davis B.L.,Austen BioInnovation Institute
Current Sports Medicine Reports | Year: 2012

A variety of physiological changes are experienced by astronauts during both short- and long-duration space missions. These include space motion sickness, spatial disorientation, orthostatic hypotension, muscle atrophy, bone demineralization, increased cancer risk, and a compromised immune system. This review focuses on countermeasures used to moderate these changes, particularly exercise devices that have been used by National Aeronautics and Space Administration astronauts over the past six decades as countermeasures to muscle atrophy and bone loss. The use of these devices clearly has shown that a microgravity environment places unusual demands on both the equipment and the human users. While it is of paramount importance to overcome microgravityinduced musculoskeletal deconditioning, it also is imperative that the exercise system (i) is small and lightweight, (ii) does not require an external power source, (iii) produces 1g-like benefits to both bones and muscles, (iv) requires relatively short durations of exercise, and (v) does not affect the surrounding structure or environment negatively through noise and/or induced vibrations. Copyright © 2012 by the American College of Sports Medicine.

Bois A.J.,Cleveland Clinic | Fening S.D.,Austen BioInnovation Institute | Polster J.,Cleveland Clinic | Jones M.H.,Cleveland Clinic | Miniaci A.,Cleveland Clinic
American Journal of Sports Medicine | Year: 2012

Background: Glenoid support is critical for stability of the glenohumeral joint. An accepted noninvasive method of quantifying glenoid bone loss does not exist. Purpose: To perform independent evaluations of the reliability and accuracy of standard 2-dimensional (2-D) and 3-dimensional (3-D) computed tomography (CT) measurements of glenoid bone deficiency. Study Design: Descriptive laboratory study. Methods: Two sawbone models were used; one served as a model for 2 anterior glenoid defects and the other for 2 anteroinferior defects. For each scapular model, predefect and defect data were collected for a total of 6 data sets. Each sample underwent 3-D laser scanning followed by CT scanning. Six physicians measured linear indicators of bone loss (defect length and width-to-length ratio) on both 2-D and 3-D CT and quantified bone loss using the glenoid index method on 2-D CT and using the glenoid index, ratio, and Pico methods on 3-D CT. The intraclass correlation coefficient (ICC) was used to assess agreement, and percentage error was used to compare radiographic and true measurements. Results: With use of 2-D CT, the glenoid index and defect length measurements had the least percentage error (-4.13% and 7.68%, respectively); agreement was very good (ICC, .81) for defect length only. With use of 3-D CT, defect length (0.29%) and the Pico 1 method (4.93%) had the least percentage error. Agreement was very good for all linear indicators of bone loss (range, .85-.90) and for the ratio linear and Pico surface area methods used to quantify bone loss (range, .84-.98). Overall, 3-D CT results demonstrated better agreement and accuracy compared to 2-D CT. Conclusion: None of the methods assessed in this study using 2-D CT was found to be valid, and therefore, 2-D CT is not recommended for these methods. However, the length of glenoid defects can be reliably and accurately measured on 3-D CT. The Pico and ratio techniques are most reliable; however, the Pico1 method accurately quantifies glenoid bone loss in both the anterior and anteroinferior locations. Future work is required to implement valid imaging techniques of glenoid bone loss into clinical practice. Clinical Relevance: This is one of the only studies to date that has investigated both the reliability and accuracy of multiple indicators and quantification methods that evaluate glenoid bone loss in anterior glenohumeral instability. These data are critical to ensure valid methods are used for preoperative assessment and to determine when a glenoid bone augmentation procedure is indicated. © 2012 The Author(s).

Zheng J.,University of Akron | Liu K.,University of Akron | Reneker D.H.,University of Akron | Becker M.L.,University of Akron | Becker M.L.,Austen BioInnovation Institute
Journal of the American Chemical Society | Year: 2012

A primary amine-derivatized 4-dibenzocyclooctynol (DIBO) was used to initiate the ring-opening polymerization of poly(γ-benzyl-l-glutamate) (DIBO-PBLG). This initiator yields well-defined PBLG polymers functionalized with DIBO at the chain termini. The DIBO end group further survives an electrospinning process that yields nanofibers that were then derivatized post-assembly with azide-functionalized gold nanoparticles. The availability of DIBO on the surface of the fibers is substantiated by fluorescence, SEM, and TEM measurements. Post-assembly functionalization of nanofiber constructs with bioactive groups can be facilitated easily using this process. © 2012 American Chemical Society.

Zhou J.,University of Akron | Xie S.,University of Akron | Amond E.F.,University of Akron | Becker M.L.,University of Akron | Becker M.L.,Austen BioInnovation Institute
Macromolecules | Year: 2013

A series of low bandgap semi-random copolymers incorporating various ratios of two acceptor units - thienothiadiazole and benzothiadiazole - were synthesized by Pd-catalyzed Stille coupling. The polymer films exhibited broad and intense absorption spectra, covering the spectral range from 350 nm up to 1240 nm. The optical bandgaps and HOMO levels of the polymers were calculated from ultraviolet-visible spectroscopy and cyclic voltammetry measurements, respectively. By changing the ratio of the two acceptor monomers, the HOMO levels of the polymers were tuned from -4.42 to -5.28 eV and the optical bandgaps were varied from 1.00 to 1.14 eV. The results indicate our approach could be applied to the design and preparation of conjugated polymers with specifically desired energy levels and bandgaps for photovoltaic applications. © 2013 American Chemical Society.

Smith Callahan L.A.,University of Akron | Xie S.,University of Akron | Barker I.A.,University of Warwick | Zheng J.,University of Akron | And 4 more authors.
Biomaterials | Year: 2013

End-functional PLLA nanofibers were fabricated into mats of random or aligned fibers and functionalized post-spinning using metal-free "click chemistry" with the peptide Tyr-Ile-Gly-Ser-Arg (YIGSR). Fibers that were both aligned and functionalized with YIGSR were found to significantly increase the fraction of mouse embryonic stem cells (mESC) expressing neuron-specific class III beta-tubulin (TUJ1), the level of neurite extension and gene expression for neural markers compared to mESC cultured on random fiber mats and unfunctionalized matrices. Precise functionalization of degradable polymers with bioactive peptides created translationally-relevant materials that capitalize on the advantages of both synthetic and natural systems, while mitigating the classic limitations of each. © 2013 Elsevier Ltd.

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