Biomedical Research Series: Dr. Gary Walker

Within the Department of Biological Sciences at Youngstown State University there are many areas of research being explored by faculty and students alike. In a new monthly series, we will highlight faculty research that covers various aspects of biomedical efforts from DNA to bacteria, fungi, and more.

Dr. Gary Walker is a professor and chairperson of Biological Sciences at YSU. He obtained a PhD in Biological Sciences from the Wayne State University of Michigan. He began graduate school with an interest in becoming a developmental biologist with focus on cell division and later in stem cells.

His interest in biomedical research began decades ago but recently changed direction when he collaborated with a local neurologist, Dr. Carl Ansevin. They wrote several papers together and heavily researched muscle proteins. Now he is mainly focusing on the basic molecular programming of muscle tissue with anticipation that he can eventually engineer a functional muscle.

Dr. Walker is currently studying the growth of muscle cell cultures to advance the fundamental understanding of muscle development and function. In addition, he is interested in tissue engineering, specifically 3D-printed structures, which will be used primarily for therapy purposes.

Given his research background, one of his goals is to create functional muscles. To create a 3D-printed tissue structure, Dr. Walker grows myoblasts in cell cultures that are then mixed with a bio gel. The bio gel aides in the suspension of the cells and maintains the 3D structure throughout the printing process. A computerized 3D fluid printer is then used to create a specific geometric structure allowing the “tissues” to transfer to culture vessels so that the myoblasts can grow.

“As you can see, these myofibers form in all sorts of directions,” said Dr. Walker. “So you can’t make a functional muscle because in a functional muscle all these fibers have to be aligned parallel.”

In the end, once the cells are understood and a live tissue is formed, Dr. Walker wants to tinker with the geometry of the tissue, making it more like a standard muscle tissue.

Once the structure is fit for usage in medical procedures, his personal hope for the 3D-printed muscle tissue is to benefit trauma patients and those who experience muscle diseases. This research project has tied together his love of growing cells and researching how functional tissues are formed. The project is also a great way to show the transition between basic and applied knowledge.

There is great potential for this research and Dr. Walker could be an important part of this advancement of biomedical technology.

Recent Publication: Biology Student, Faculty, and Staff

Thomas DR, Chadwell BA, Walker GR, Budde JE, Vandeberg JL, Butcher MT. “Ontogeny of myosin isoform expression and prehensile function in the tail of the gray short-tailed opossum (Monodelphis domestica),” Journal of Applied Physiology, May 2017. DOI: 10.1152/japplphysiol.00651.2016

Former YSU biology student Dylan Thomas authored this paper in collaboration with faculty and staff from YSU, Ohio University, and the University of Texas Rio Grande Valley. The paper was submitted in July 2016 and was accepted and published in May 2017 by the American Physiological Society.


Terrestrial opossums use their semi-prehensile tail for grasping nesting materials as opposed to arboreal maneuvering. We relate the development of this adaptive behavior with ontogenetic changes in myosin heavy chain (MHC) isoform expression from 21 days to adulthood. Monodelphis domestica is expected to demonstrate a progressive ability to flex the distal tail up to age 7 months, when it should exhibit routine nest construction. We hypothesize that juvenile stages (3-7 months) will be characterized by retention of the neonatal isoform (MHC-Neo), along with predominant expression of fast MHC-2X and 2B, which will transition into greater MHC-1β and 2A isoform content as development progresses. This hypothesis was tested using Q-PCR to quantify and compare gene expression of each isoform to its protein content determined by gel electrophoresis and densitometry. These data were correlated with nesting activity in an age-matched sample of each age group studied. Shifts in regulation of MHC gene transcripts matched well with isoform expression. Notably, mRNA for MHC-Neo and 2B decrease, resulting in little-to-no isoform translation after age 7 months, whereas mRNA for MHC-1β and 2A increase, and this corresponds with subtle increases in content for these isoforms into late adulthood. Despite the tail remaining intrinsically fast-contracting, a critical growth period for isoform transition is observed between 7 and 13 months, correlating primarily with use of the tail during nesting activities. Functional transitions in MHC isoforms and fiber type properties may be associated with muscle ‘tuning’ repetitive nest remodeling tasks requiring sustained contractions of the caudal flexors.

Faculty Publication: Dr. Jim Andrews

Daniel Wehrung, Elaheh. A. Chamsaz, James H. Andrews, Abraham Joy, and Moses O. Oyewumi, “Engineering Alkoxyphenacyl-Polycarbonate Nanoparticles for Potential Application in Near-Infrared Light-Modulated Drug Delivery via Photon Up-Conversion Process,” Journal of Nanoscience and Nanotechnology 17, 4867-4881 (2017). 

This publication describes the results of experiments primarily done at NEOMED, but also at YSU’s Dept. of Physics & Astronomy, using nano-crystals to convert near infrared light to ultraviolet light. Typically, ultraviolet light is difficult to apply as a form of medical phototherapy due to its harmful effects to other tissues. Using the materials studied in this paper, the primary exposure would instead be to infrared light that is then converted to ultraviolet at the site of the phototherapy for localized treatment. This work was led by Daniel Wehrung as part of his successful PhD dissertation work at NEOMED under the supervision of Dr. Moses Oyewumi in the Department of Pharmaceutical Sciences. Dr. Andrews assisted with experiments at YSU as part of this study.


Photoresponsive delivery systems that are activated by high energy photo-triggers have been accorded much attention because of the capability of achieving reliable photoreactions at short irradiation times. However, the application of a high energy photo-trigger (UV light) is not clinically viable. Meanwhile, the process of photon-upconversion is an effective strategy to generate a high energy photo-trigger in-situ through exposure to clinically relevant near-infrared (NIR) light. In this regard, we synthesized photon upconverting nanocrystals (UCNCs) that were subsequently loaded into photoresponsive nanoparticles (NPs) prepared using alkoxyphenacyl-based polycar- bonate homopolymer (UCNC-APP-NPs). UCNC loading affected resultant NP size, size distribu- tion, colloidal stability but not the zeta potential. The efficiency of NIR-modulated drug delivery was impacted by the heterogenetic nature of the resultant UCNC-APP-NPs which was plausibly formed through a combination of UCNC entrapment within the polymeric NP matrix and nucleation of polymer coating on the surface of the UCNCs. The biocompatibility of UCNC-APP-NPs was demonstrated through cytotoxicity, macrophage activation, and red blood cell lysis assays. Studies in tumor-bearing (nu/nu) athymic mice showed a negligible distribution of UCNC-APP-NPs to retic- uloendothelial tissues. Further, distribution of UCNC-APP-NPs to various tissues was in the order (highest to lowest): Lungs > Tumor > Kidneys > Liver > Spleen > Brain > Blood > Heart. In all, the work highlighted some important factors that may influence the effectiveness, reproducibility biocompatibility of drug delivery systems that operate on the process of photon-upconversion.

Faculty Publication: Robert J. Korenic

Robert J. Korenic, Associate Professor, Civil and Construction Engineering Technology, presented a paper entitled “Youngstown State University ‘Gateway Project’ Rain Garden Design Upgrades.” The paper was presented at the Engineering Sustainability Innovation and the Triple Bottom Line Conference on April 10, 2017 in Pittsburgh, PA. This is a national conference affiliated with the University of Pittsburgh Swanson School of Engineering and the Mascaro Center for Sustainable Innovation.

Robert J. Korenic



The Youngstown State University (YSU) “Gateway Project,” completed several years ago, was a large scale grounds and facilities project intended to upgrade several campus buildings and the grounds surrounding these facilities. Many of the upgrades utilized Leadership in Energy and Environmental Design (LEED) sustainable design criteria. Included in these upgrades was the installation of bioswale and rain garden areas intended to help manage storm water runoff from new parking facilities. While the bioswales are functioning as intended, the rain garden has never maintained plant life and is not functioning to manage storm water runoff. Phase one of this research involved testing the hydraulic conductivity of the soil in the garden, sampling the soil for its pH and identifying the soil stratification in the garden by digging test pits. This document will recap the results of that research and build on those results by specifying how the rain garden can be rebuilt in order to properly manage the storm water runoff.

Faculty Publications: Nguyet Nguyen

Paper Title: “Hidden Markov Model for Portfolio Management with Mortgage-Backed Securities Exchange-Traded Fund” was published on the Society of Actuaries website in April. This project was funded by the finance research grants from SOA, from June 2016-June 2017.


The hidden Markov model (HMM) is a regime-shift model that assumes observation data were driven by hidden regimes (or states). The model has been used in many fields, such as speech recognition, handwriting recognition, biomathematics and financial economics. In this paper, we describe HMM and its application in finance and actuarial areas. We then develop a new application of HMM in mortgage-backed securities exchange-traded funds (MBS ETFs). We begin with a primer on the hidden Markov model, covering main concepts, the model’s algorithms and examples to demonstrate the concepts. Next, we introduce some applications of the model in actuarial and financial areas. We then present applications of HMM on MBS ETFs. Finally, we establish a new use of HMM for a portfolio management with MBS ETFs: predicting prices and trading some MBS ETFs. Data, algorithms and codes generated in this paper can be used for future research in actuarial science and finance.

Paper Title: “Using the Hidden Markov Model to Improve the Hull-White Model for Short Rate”, a collaboration work with Thomas Wakefield, YSU, and Dung Nguyen, Ned Davis Research Group, was accepted to publish in the International Journal of Trade, Economics and Finance.

Recent Publication: Abdullah Kuraan, Stefan Moldovan, Kyosung Choo

Abdullah M. Kuraan, Stefan I. Moldovan, Kyosung Choo, “Heat transfer and hydrodynamics of free water jet impingement at low nozzle-to-plate spacings,” International Journal of Heat and Mass Transfer 108 (2017) 2211-2216.


In this study, heat transfer and hydrodynamics of a free water jet impinging a flat plate surface are experimentally investigated. The effects of the nozzle-to-plate spacing, which is equal to or less than one nozzle diameter (H/d = 0.08–1), on the Nusselt number, hydraulic jump diameter, and pressure at the stagnation point are considered. The results show that the normalized stagnation Nusselt number, pressure, and hydraulic jump diameter are divided into two regions: Region (I) jet deflection region (H/d ⩽ 0.4) and Region (II) inertia dominant region (0.4 < H/d ⩽ 1). In region I, the normalized stagnation Nusselt number and hydraulic jump diameter drastically increase with decreasing the nozzle-to-plate spacing, since the stagnation pressure increases due to the jet deflection effect. In region II, the effect of the nozzle-to-plate spacing is negligible on the normalized stagnation Nusselt number and hydraulic jump diameter since the average velocity of the jet is constant, which means the jet deflection effect disappears. Based on the experimental results, new correlations for the normalized hydraulic jump diameter, stagnation Nusselt number, and pressure are developed as a function of the nozzle-to-plate spacing alone.

Faculty Faction: Dr. Eric MacDonald

Eric MacDonald

photo credit: YSU News Center

Dr. Eric MacDonald is a professor of electrical engineering and YSU’s Friedman Chair in Engineering. He holds a BS, MS, and PhD in Electrical Engineering from the University of Texas at Austin.

He worked as a professor at the University of Texas at El Paso for 15 years after leaving industry as a chip designer. He created microprocessors for products including computers and game systems and he worked for companies like IBM and Motorola.

In 2003, Dr. MacDonald teamed up with a mechanical engineer at UTEP to experiment with the mixing of 3D printing and electronics, which was almost unheard of at that time.

“So you could make a ball that’s a circuit board for instance, or you could make a prosthetic hand,” said Dr. MacDonald. “We ended up getting a lot of interest from NASA and the National Science Foundation, the Department of Defense, the intelligence community even.”

He had strong ties to Youngstown before he even considered coming here to teach.

“In 2011, President Obama in his State of the Union address basically said that he was going to invest in manufacturing by setting up institutes, the first of which was additive manufacturing… and it came to Youngstown,” said Dr. MacDonald.

A grant from this institute based in Youngstown brought him and Dr. Brett Conner together for collaboration.

Dr. MacDonald was very interested in coming to Youngstown through a recent endowment. He is now the first Morris and Phyllis Friedman Chair in Engineering at Youngstown State University.

He plans to continue his hands-on research with 3D printing and electronics while also incorporating Youngstown’s history of metal manufacturing.

Last semester, Dr. MacDonald published a paper in the journal Science along with former colleague Ryan Wicker of UTEP. Science is a highly prestigious magazine and it is very difficult to be accepted for publication.

A frequent traveler, Dr. MacDonald has been to many different countries all over the world. Even so, he still thinks Ohio is a beautiful place to live.

STEM Faculty Awarded Research Professorships

In accordance with the YSU-OEA Agreement, at least eighteen faculty members shall be designated “Research Professors” each year. The language in the agreement specifies that:

“The Research Professorship Committee may award a minimum of six (6) hours to a maximum of nine (9) hours; the total number of hours distributed will be no less than 162 hours.”

Proposals from thirty-two faculty members, submitted for research professorships, were reviewed and evaluated by a seven-member committee. Graduate faculty members representing all six colleges were on the committee which awarded 22 research professorships for the 2017-2018 academic year. Congratulations to the research professors.

Research Professorship Committee
Dr. Rebecca Badawy
Mr. Michael Hripko (Chair)
Dr. Daniel Keown
Dr. Mary LaVine
Dr. Susan Lisko
Dr. Dolores Sisco
Dr. Tom Wakefield

STEM Research Professors

Dr. Snjezana Balaz, Physics and Astronomy – Awarded 6 Hours
“Investigation of Charge Transfer in Organic Interfaces”

Dr. Ganesaratnam Balendiran, Chemistry – Awarded 9 Hours
“Role of Fibrates and Like Molecules in Diabetes and Metabolic Diseases”

Dr. Kyosung Choo, Mechanical and Industrial Engineering – Awarded 6 Hours
“Heat Transfer Enhancement of Steel Pipe”

Dr. Douglas Genna, Chemistry – Awarded 9 Hours
“Removal of Common Water Contaminants using Select Porous Materials”

Dr. Johanna Krontiris-Litowitz, Biology – Awarded 9 Hours
“Inserting Quantitative Literacy into the Human Physiology Lab Curriculum”

Dr. Xiangjia Min, Biological Sciences – Awarded 6 Hours
“Expanding the plant alternative splicing database”

Dr. Moon Nguyen, Mathematics and Statistics – Awarded 6 Hours
“Ohio Extreme Weather Forecast using Hidden Markov Model”

Dr. Jae Joong Ryu, Mechanical Engineering – Awarded 9 Hours
“Influence of biochemical environment on synovial lubrication and surface wear of prosthetic knee joints”

Dr. Bonita Sharif, CSIS – Awarded 9 Hours
“An eye tracking experiment summarizing API elements using code and documentation”

Dr. Suresh Sharma, Civil/Environmental and Chemical Engineering – Awarded 9 Hours
“Investigating Temporal and Spatial Variability of Flow and Salinity Level in the Mentor Marsh Watershed”

Recent Publication: Biology Faculty & Students

STEM faculty members on the paper: Xiangjia “Jack” Min, Feng Yu, Chester Cooper
STEM graduate students:  Brian Powell, Vamshi Amerishetty, John Meinken
STEM undergraduate student: Geneva Knott

Powell B., Amerishetty V., Meinken J., Knott G., Feng Y., Cooper C., and Min X.J., 2016, “ProtSecKB: the protist secretome and subcellular proteome knowledgebase,” Computational Molecular Biolog 6(4): 1-12.


Kingdom Protista contains a large group of eukaryotic organisms with diverse lifestyles. We developed the Protist Secretome and Subcellular Proteome Knowledgebase (ProtSecKB) to host information of curated and predicted subcellular locations of all protist proteins. The protist protein sequences were retrieved from UniProtKB, consisting of 1.97 million entries generated from 7,024 species with 101 species including 127 organisms having complete proteomes. The protein subcellular locations were based on curated information and predictions using a set of well evaluated computational tools.  The database can be searched using several different types of identifiers, gene names or keyword(s). Secretomes and other subcellular proteomes can be searched or downloaded. BLAST searching against the complete set of protist proteins or secretomes is available.  Protein family analysis of secretomes from representing protist species, including Dictyostelium discoideum, Phytophthora infestans, and Trypanosoma cruzi, showed that species with different lifestyles had drastic differences of protein families in their secretomes, which may determine their lifestyles. The database provides an important resource for the protist and biomedical research community. The database is available at

Recent Publication: Dr. Jai K. Jung

Editors’ Choice – Canadian Geotechnical Journal – December 201

Jai K. Jung, Thomas D. O’Rourke, Christina Argyrou“Multi-directional force–displacement response of underground pipe in sand,” Canadian Geotechnical Journal, 2016, 53(11): 1763-1781.

This paper is part of a Special Issue entitled “Pipeline geotechnics”.


A methodology is presented to evaluate multi-directional force–displacement relationships for soil–pipeline interaction analysis and design. Large-scale tests of soil reaction to pipe lateral and uplift movement in dry and partially saturated sand are used to validate plane strain, finite element (FE) soil, and pipe continuum models. The FE models are then used to characterize force versus displacement performance for lateral, vertical upward, vertical downward, and oblique orientations of pipeline movement in soil. Using the force versus displacement relationships, the analytical results for pipeline response to strike-slip fault rupture are shown to compare favorably with the results of large-scale tests in which strike-slip fault movement was imposed on 250 and 400 mm diameter high-density polyethylene pipelines in partially saturated sand. Analytical results normalized with respect to maximum lateral force are provided on 360° plots to predict maximum pipe loads for any movement direction. The resulting methodology and dimensionless plots are applicable for underground pipelines and conduits at any depth, subjected to relative soil movement in any direction in dry or saturated and partially saturated medium to very dense sands.

Recent Publication: Dr. Kyosung Choo

Brian K. Friedrich, Tamira D. Ford, Aspen W. Glaspell, Kyosung Choo, “Experimental study of the hydrodynamic and heat transfer of air-assistant circular water jet impinging a flat circular disk,” International Journal of Heat and Mass Transfer Volume 106 (March 2017) 804-809.


Hydrodynamic and heat transfer characteristics of the circular hydraulic jump by air-assistant water jet impingement was experimentally investigated using water and air as the test fluid. The effects of volumetric quality (β = 0–0.9) on the hydraulic jump radius, local Nusselt number and, pressure at the stagnation point were considered under fixed water-flow-rate condition. The results showed that the dimensionless hydraulic jump radius increased with volumetric quality, attained a maximum value at around 0.8 of the volumetric quality, and then decreased. The hydraulic jump of two phase impinging jet is governed by the stagnation pressure and the lateral variation of Nusselt number is governed by hydraulic jump radius. Based on the experimental results, a new correlation for the normalized hydraulic jump radius of the impinging jet are developed as a function of the normalized stagnation pressure alone.

Recent Publications: John Martin

John Martin, an assistant professor of engineering technology at Youngstown State University, has recently presented for the American Society for Engineering Education and the American Society of Mechanical Engineers. Martin holds a bachelor’s and master’s degree in mechanical engineering and his research area is in engineering education.

Work in Progress: The Effects of Concurrent Presentation of Engineering Concepts and FEA Applications”, Martin, J., Martin, A., Proceedings of the 2016 ASEE Annual Conference and Expo, New Orleans, LA, June, 2016.

“CFD Analysis Comparing Steady Flow and Pulsatile Flow through the Aorta and its Main Branches”, Martin, J., Proceedings for the 2016 ASME International Mechanical Engineering Congress & Exposition, Phoenix, AZ, November, 2016.

Faculty Research – Dr. Suresh Sharma

Dr. Suresh SharmaOriginally from Nepal, Dr. Suresh Sharma is an assistant professor in the Civil/Environmental and Chemical Engineering Department at Youngstown State University.

He worked for several years in Nepal as a government engineer before joining a PhD study in 2008. In 2012, he completed his PhD in Civil Engineering (Water Resources) from Auburn University, USA. Dr. Sharma worked as a Post-doctoral Research Associate at Purdue University for a year before joining the faculty ranks at YSU in 2013.

Dr. Sharma is interested both in hydrologic and water quality modeling. He has diverse research experiences working with data-driven modelling such as wavelet analysis, neural network, fuzzy logic, and semi-distributed and distributed watershed models.

Currently, Dr. Sharma is working on research projects including hydrologic investigation in wetlands, climate change impact on flooding, low flows, ice jams and snow fall in the northern belt of the United States. He is also conducting field-based research by collecting data from wetlands to develop various scenarios using a watershed model.

Dr. Sharma teaches graduate and undergraduate level courses such as Water Quality Modeling (graduate level), Hydrology (graduate level), Hydraulic Design, Fluid Mechanics and Statics. He will also teach Watershed Modelling (graduate level) beginning in spring 2017.

Dr. Sharma participates in regional and international conferences, typically 2 to 3 times a year. He is involved in various scientific committees and also represents the college as an editorial board member of some peer-reviewed journals.

In addition to his academic pursuits, Dr. Sharma is interested in social service such as donating blood, which he tries to do every two to three months. Dr. Sharma hopes to serve society in a unique way after retirement. For more information on Dr. Sharma’s research and publications, visit his page on the YSU website.

Recent Publication: Faculty and Students in Physics & Astronomy

Michael Crescimanno and Jim Andrews, Professors in Physics & Astronomy, together with students Brandon Latronica and Maddie Smotzer, co-authored the paper “Linear distributed Bragg cavity effects on optical limiting in two- and three-level media,” to appear in a special December issue of the Journal of the Optical Society of America on the topic “Nonlinear Optics near the Fundamental Limit.” This work was funded through grants from the National Science Foundation. 


A lumped distributed Bragg reflector (DBR)-nonlinear layer-DBR system is used to explore how nonlinear optical effects (in particular, optical limiting) are modulated by the dispersive character of the (optically linear) DBR. A three-level quantum optics model of the nonlinear layer is used to find self-consistent numerical solutions to the (nonlinear) optical transport in the composite system. We find that the intensity dependence of the real part of the index can be combined with the dispersion in the (linear) DBR to cause optical limiting even for materials that have only a saturated absorber (two-level) response.

Recent Publication: Dr. Eric MacDonald

“Multiprocess 3D printing for increasing component functionality”
Published in Science Vol. 353, Issue 6307.


Science Magazine coverLayer-by-layer deposition of materials to manufacture parts—better known as three-dimensional (3D) printing or additive manufacturing—has been flourishing as a fabrication process in the past several years and now can create complex geometries for use as models, assembly fixtures, and production molds. Increasing interest has focused on the use of this technology for direct manufacturing of production parts; however, it remains generally limited to single-material fabrication, which can limit the end-use functionality of the fabricated structures. The next generation of 3D printing will entail not only the integration of dissimilar materials but the embedding of active components in order to deliver functionality that was not possible previously. Examples could include arbitrarily shaped electronics with integrated microfluidic thermal management and intelligent prostheses custom-fit to the anatomy of a specific patient. We review the state of the art in multiprocess (or hybrid) 3D printing, in which complementary processes, both novel and traditional, are combined to advance the future of manufacturing.