Master of Science (MS), Ohio University, 2013, Geological Sciences (Arts and Sciences)

This study focused on furthering the development of a novel, cost-effective scheme to remediate large, dilute plumes of DNAPLs in groundwater through the in-situ, well-based emplacement of concentrated permanganate solution mixed with a gelling agent. The controlled-release permanganate gel (CRP-G) solution was developed so that it may be injected and flow with groundwater and subsequently increase in viscosity over time to remain emplaced and slowly release MnO4- in a long-term, controlled release fashion. This study characterized CRP-G gelation and release mechanisms of MnO4- in saturated porous media through the execution of batch experiments, viscosity tests, and column tests. Specific attention was devoted to use of colloidal silica within the CRP-G. Results of batch tests indicated that gelation times can be modified on the order of 5 min to over 10 dys; dilution by flowing water in the subsurface will be a consideration upon gel engineering. Results of column tests in open water indicated that release of MnO4- from CRP-G occurred within 24 hrs. In column tests conducted with saturated, sandy media, gelation occurred within 1, 3, and 6 hrs when using CRP-G solution 25.0, 23.0, and 22.9 g/L of KMnO4. Permanganate mass flux approached values that are near the benchmark for this study (˜ 850 µg/day), with release lasting up to 3 dys. This release was characterized as rapid short-term release followed by a longer, stabilized release phase. Impact of dilution of the injected CRP-G solution in the subsurface will be a consideration upon gel formation. The use of colloidal silica as a controlled-release material for the CRP-G is promising. Further studies are warranted for the development of a novel remediation scheme using the CRP-G.

Committee: Eung Seok Lee Ph.D. (Advisor); Douglas Green Ph.D. (Committee Member); Dina Lopez Ph.D. (Committee Member) Subjects: Environmental Engineering; Environmental Geology; Environmental Studies

Master of Science in Engineering, Youngstown State University, 2022, Department of Civil/Environmental and Chemical Engineering

Precise control over the release of drugs from wearable bioelectronic devices on wound sites, such as quantity and timing, is highly desirable in order to optimize wound treatment. The aim of this study is to obtain and characterize an electro-responsive ferrocene-chitosan/alginate polyelectrolyte complex (PEC) hydrogel that can be used as a smart wound dressing. First, chitosan/alginate PEC hydrogel was obtained as a control and characterized in terms of chemical properties and drug release kinetics. Natural chitosan (CHI) was chemically conjugated with ferrocene (Fc) moieties to create Fc-CHI. The Fc-CHI was interacted with alginate (ALG) to form Fc-CHI/ALG PEC through electrostatic interaction. The turbidity test was performed to find the optimum ratio between the Fc-CHI and ALG, thus the stoichiometric PEC hydrogel. The PEC hydrogel was characterized by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometer (EDS), in addition to the swelling behavior and gel content tests. Comparative analysis of the ATR-FTIR spectra of CHI, Fc-CHI, ALG, and their mixtures indicated the formation of a polyelectrolyte complex. The SEM images showed the porosity of the PEC. The EDS analysis proved the incorporation of the Fc into the CHI by the appearance of the Fc peaks in the analysis. The PEC hydrogel showed a comparative swelling percentage to be 4400% and also showed excellent stability, proved by almost 100% gel content after incubation in phosphate buffer saline (PBS) solution. To demonstrate the drug delivery potential of the developed PEC-based wound dressing, fluorescence (FITC) and FITC-Dextran were used as model drugs. First, the drug loading and release kinetics of the PEC were studied in solution. In three days, about 83% and 61% were released of the FITC, and FITC-Dextran, respectively in PBS solution. Secondly, the drug release properties on the phantom skin surface (a (open full item for complete abstract)

Committee: Byung-Wook Park PhD (Advisor); Pedro Cortes PhD (Committee Member); Holly Martin PhD (Committee Member) Subjects: Biomedical Engineering; Chemical Engineering; Materials Science

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2020, Photochemical Sciences

We present the study of Fe(III)-carboxylate photochemistry of natural polyuronates in aqueous solutions and in soft hydrogel materials with near UV and violet light. Described in this dissertation are the use of Fe(III)-carboxylate photochemistry for sustainable material applications such as surface modifications and controlled plant nutrient delivery. Quantitative photochemistry of the Fe(III)-alginate system in aqueous solutions was studied using near UV light, and the effect of factors such as alginate composition and solution pH was studied. Degradation of alginate chain with the photochemical reaction was observed by the changes in the solution viscosity. The photochemical reaction seemed to proceed through a radical species and the generation of carbon dioxide anion radical (CO2.-) was identified using Electron Paramagnetic Resonance (EPR) spectroscopy. We present all polysaccharide hydrogels prepared with agarose and carboxylate group containing pectin which showed photoresponsive behavior. Upon Fe(III) coordination and irradiation with 405 nm LED for various time intervals, these gels changed their pH, mechanical properties, porous structure and swelling properties. Based on the radical generation phenomenon, studies on polymerization of selected acrylic monomers using this Fe(III)-carboxylate photochemical system was studied. Other than polyuronate based hydrogels, fabrics with introduced carboxylate functionality showed their ability to polymerize acrylic monomers on their surface, and change their physical and mechanical properties with the use of light. Hydrogel beads prepared with alginate or alginate and other polysaccharide mixtures with Fe(III) showed their ability to absorb phosphate ions from model waste solutions. The solution phosphate concentration dependent phosphate uptake showed a maximum phosphate uptake around 1.5 mgg-1. Phosphate uptake above 1 mgg-1 was seen for a wide pH range of 4.8 - 11.5 due to the strong binding betwe (open full item for complete abstract)

Committee: Alexis Ostrowski PhD (Advisor); Pavel Anzenbacher PhD (Committee Member); George Bullerjahn PhD (Committee Member); Lewis Fulcher PhD (Other) Subjects: Agriculture; Biogeochemistry; Chemistry; Environmental Science; Geochemistry; Inorganic Chemistry; Materials Science; Polymers

Master of Science, University of Akron, 2019, Polymer Science

Adequate post-operative pain management has been proven to enhance the healing and recovery of patients following most major procedures.1 However, it remains significantly under managed and is a serious unmet need in the medical field. The mainstay of post-operative pain management is the prescription of oral opioids, which, although effective, have many pitfalls. Most notably, opioids prescriptions are currently based on a “one-size-fits-all” model, providing an imbalance of doses given to patients and leaving the medication at the risk for misuse and abuse. Opioids are still in practice today ultimately due to a lack of a better solution. Herein, we propose a drug-loaded polymer film to control post-operative pain. Poly(ester urea)s were used to load drugs into solvent cast blade-coated films and tested for drug release of non-opioids agents. Specifically, etoricoxib, a selective cyclooxygenase isoform 2 (COX-2) was used to monitor the efficacy of delivery from these films both in vitro and in a rat model. To obtain different release profiles, film thickness, drug-load, and polymer composition was analyzed in order to get desired profile for analgesic release. The polymer analogs that were implemented for this study are copolymers, 10%, 20% and 30% 1-PHE-6 P(1-VAL-8), and homopolymers, P(1-VAL-8), P(1-VAL-10), and P(1-VAL-12). Moreover, a multi-modal analgesia model with bupivacaine (a local anesthetic) has been sought out to show the versatility of this device. The goal of this study was to study a controlled release system that will produce little to no inflammation while providing pain relief for 3-5 days following a surgical procedure. Ultimately, this device's intended purpose is to replace or minimize the need for prescription opioids. We hypothesize that by tuning the multiple factors available with PEUs that a variety of drug release profiles can be obtained to fit a number of different applications (i.e. acute to chronic pain).

Committee: Matthew Becker (Advisor); Andrey Dobrynin (Committee Member) Subjects: Biomedical Research; Polymers

Master of Science, University of Toledo, 2018, Chemical Engineering

The release of low acyl gellan gum from a controlled release system was evaluated at 0, 0.5, 1% concentration of tri-calcium phosphate. Release rates of 6.387, 0.345, and 0.679 mg/h of low acyl gellan gum were obtained for the 0, 0.5, and 1% tri-calcium phosphate, respectively. Additionally, rheological properties were obtained for the 0.5% TCP gel and 1% TCP. Moreover, low acyl gellan gum was enzymatically cleaved into two smaller molecular weight products, named midi-GAGR and mini-GAGR. Rheological testing revealed molecular weights of approximately 5,500 Da and 1,300 Da for midi-GAGR and mini-GAGR, respectively. Furthermore, the antioxidant capacities of both products were evaluated using DPPH assay. Midi-GAGR was able to scavenge 23% of free radicals, while mini-GAGR scavenged 13%. The polysaccharide low acyl gellan gum has shown promise to be engineered to fit clinical applications.

Committee: Dong-Shik Kim (Committee Chair); Joshua Park (Committee Member); Yakov Lapitsky (Committee Member) Subjects: Chemical Engineering

PhD, University of Cincinnati, 2018, Pharmacy: Pharmaceutical Sciences/Biopharmaceutics

Controlled release oral dosage form offers great advantages over conventional dosage form by providing steady drug plasma concentration, decreasing the frequency of administration, and providing enhanced patient compliance. However, orally ingested tablet is exposed to varying pH conditions and fluctuating mechanical agitations during its travel through the gastrointestinal tract (GIT). Selection of materials that provide controlled release mechanism to the oral dosage form is important as they can a) minimize drug release rate fluctuations for ionizable drugs during its travel along the changing pH environment of the GIT and b) maintain the release rate mechanism even when subjected to the physiological mechanical agitation forces. To examine these two important requirements, matrix tablets prepared using low glass transition temperature (Tg) silicone pressure sensitive adhesive (PSA) were evaluated and compared with matrix tablets prepared using high Tg ethyl cellulose (EC). Specifically, the effect of dissolution medium pH on drug release from binary tablets consisting of the polymer and ionizable model drugs verapamil hydrochloride and diclofenac sodium was studied using USP dissolution apparatus (without mechanical stress). The effect of simulated physiological mechanical stress agitation on drug release was studied using dissolution stress test apparatus for non-ionizable model drug acetaminophen. Mechanical properties, physical structures, electrical resistance, water uptake, and contact angle of pure polymer films and of matrix tablets were studied to understand the relationships of these factors to drug release. Our study indicated that increasing polymer amount decreased drug release rate from both silicone PSA and EC tablets using USP dissolution apparatus. However, silicone PSA tablets showed lower friability compared to EC tablets. The application of physiological simulated mechanical stress affected drug release from high Tg EC tablets that resulte (open full item for complete abstract)

Committee: Kevin Li Ph.D. (Committee Chair); Pankaj Desai Ph.D. (Committee Member); Sergey Grinshpun Ph.D. (Committee Member); Gerald Kasting Ph.D. (Committee Member); Gary Kelm Ph.D. (Committee Member); R. Randall Wickett Ph.D. (Committee Member) Subjects: Pharmaceuticals

Doctor of Philosophy, University of Akron, 2017, Chemical Engineering

This dissertation describes the design and development of several sustained delivery systems based on alginate for delivering small hydrophilic drugs. The release behaviors and specific release mechanisms were investigated to determine how each system prolongs the release of hydrophilic drugs from alginate. The first approach utilizes the coating of a hydrophobic organosilane, octadecyltrichlorosilane (OTS), to hydrophilic alginate microspheres (Alg-Ms), the hydrogel drug carrier, to sustain the release of sodium benzoate (NaB), a model hydrophilic drug. The hydrophobicity of Alg-Ms increased with the incorporated OTS concentration, prolonging the release duration of NaB from hours to days. The release mechanism of NaB from Alg-Ms switched from combined diffusion/polymer relaxation to diffusion as the amount of OTS incorporated increased. The results demonstrate the simplicity of improving hydrophobicity of hydrogel drug carriers using OTS to broaden the drug delivery applications of hydrogels in delivering small hydrophilic drugs. The second coating based method applies layer-by-layer (LbL) deposition of polyelectrolyte to alginate microgels. The polyelectrolyte shell acted as an effective diffusion barrier to extend the release of hydrophilic compounds of NaB and zosteric acid (ZA) from a few hours up to 3 days and 5 days, respectively, as the LbL deposited layer thickness increased. The deposition of polyelectrolyte onto Alg-Ms was confirmed by with microscopic imaging. The release of NaB and ZA was found to be proportional to the bilayers' number and followed the Fickan 2nd law of diffusion. The results indicate that LbL polyelectrolytes coated Alg-Ms have a potential as controlled drug-delivery devices for hydrophilic drugs. The third platform involves a modified double-emulsion technique to generate alginate based poly lactic-co-glycolic acid (PLGA) microparticles for controlling hydrophilic drug (e.g., NaB) delivery. The formulation parameters, such as (open full item for complete abstract)

Committee: Bi-min Zhang Newby Dr (Advisor); Gang Cheng Dr (Committee Member); Jie Zheng Dr (Committee Member); Leah Shriver Dr (Committee Member); Marnie Saunders Dr (Committee Member) Subjects: Biomedical Engineering; Biomedical Research; Chemical Engineering; Chemistry; Materials Science; Medicine; Pharmaceuticals; Polymer Chemistry; Polymers

PhD, University of Cincinnati, 2017, Engineering and Applied Science: Chemical Engineering

Cancer is still a major threat to public health worldwide. Thanks to the extensive studies in cancer biology and growing understanding in cancer, many novel and effective therapeutic agents and drug combinations have been discovered and designed. However, many of them are challenged in reaching their targeted site. Nano-scaled drug carriers that target and deliver therapeutic agents to the sites of diseases have shown great promises in cancer treatment. As a starting point, we designed a human epidermal growth factor receptor 2 (HER-2) targeting pH sensitive nanoparticle combining the advantages of polyhistidine (PHis) and Herceptin. This nanoparticle contains a pH sensitive hydrophobic core in which chemotherapeutic drug is loaded and hydrophilic layer which stabilizes the whole nanoparticle while providing active targeting to HER-2. This nanoparticle shows a pH triggered drug release (i.e. fast drug release at acidic condition and sustained release at physiological condition), a capability of endosomal escape which allows delivery of cargo to cytoplasm, and HER-2 targeting which enhances cellular uptake of the nanoparticle. This work is described in detail in chapter 2. In addition, there are growing needs in delivery of micro RNA inhibitor (miRi) for RNA interferences (RNAi). In chapter 3, a novel lipid coated calcium phosphate miRi complex was made to address poor encapsulation of hydrophilic RNA molecules in hydrophobic polymeric core for co-delivery of molecules with different physicochemical properties. This novel complex was co-encapsulated with paclitaxel in nanoparticle to achieve co-delivery. The co-delivery nanoparticle was found effective in regulating gene expression in vitro. The synergistic effects of co-delivery of miRi and paclitaxel were confirmed in culture cells. In the last part of the study, chapter 4-5 were focused on developing drug delivery systems address the unmet needs for systematic sequential delivery of combination th (open full item for complete abstract)

Committee: Joo Youp Lee Ph.D. (Committee Chair); Chia Chi Ho Ph.D. (Committee Member); Yoonjee Park Ph.D. (Committee Member); Susan Waltz Ph.D. (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 1986, Graduate School

Committee: Not Provided (Other) Subjects: Health Sciences

Doctor of Philosophy, The Ohio State University, 1980, Graduate School

Committee: Not Provided (Other) Subjects: Health Sciences

Doctor of Philosophy, The Ohio State University, 1980, Graduate School

Committee: Not Provided (Other) Subjects: Chemistry

Master of Sciences, Case Western Reserve University, 2015, Biomedical Engineering

Cells adapt themselves to the dynamic extracellular environment by responding to numerous signal stimuli. Strategies for engineering stimulus-responsive biomaterials as drug delivery vehicles may mimic this responsiveness and allow for spatiotemporal control over drug delivery. Short interfering RNA (siRNA) can inhibit specific gene expression by cleaving complementary mRNA molecules, which may be useful when presented in a stimulus-responsive manner. Here, a photodegradable hydrogel system was developed for siRNA delivery, and the release of siRNA complexed with poly(ethyleneimine) (siRNA/PEI) from photodegradable hydrogels was tailored by the trigger of UV exposure. Photodegradable poly (ethylene glycol)-based hydrogels containing siRNA/PEI complexes have been successfully fabricated, and light-triggered release of siRNA and gene-silencing abilities of released siRNA in cells cultured in monolayer has been shown using green fluorescent protein as a reporter. Future work can extend this platform technology to temporally control biologically relevant processes in an “on-demand” manner.

Committee: Eben Alsberg (Advisor); Zheng-Rong Lu (Committee Member); Nicole Steinmetz (Committee Member) Subjects: Biomedical Engineering

Master of Science, University of Toledo, 2014, Chemical Engineering

Underwater adhesives have several potential applications in industry as well as in medicine. Much of the recent research in this area has focused on adhesive preparation from biological or custom-designed biomimetic polymers. As a simpler alternative, we have recently shown that ionically crosslinked, gel-like underwater adhesive complexes can be prepared by the mixing of the readily-available and inexpensive polyelectrolyte, poly(allylamine hydrochloride) (PAH), with commonly-used multivalent anions, pyrophosphate (PPi) and tripolyphosphate (TPP). Remarkably, these gel-like complexes adhere to both hydrophilic and hydrophobic substrates under water with tensile adhesive strength considerably greater than that of Scotch Permanent Double Sided Tape (up to ~400 kPa vs. ~85 kPa when used as a pressure-sensitive adhesives) and due to the reversible nature of the ionic crosslinks, self-heal when torn. These complexes also exhibit very high storage moduli (greater than 100 kPa), indicative of a very high crosslink density. The high crosslink density allow these gel-like complexes to also entrap and deliver small molecule payloads over multiple-month timescales. Moreover, their formation and rheological/adhesion properties can be controlled using external stimuli (pH and ionic strength). In this thesis we characterize formation and rheological/adhesion properties of gel-like PAH/PPi and PAH/TPP complexes the through the use of dynamic and electrophoretic light scattering, rheology and tensile adhesion tests. We also describe their sensitivity to pH and ionic strength, and explain how the complexes can be dissolved on demand by raising or lowering the ambient pH, and can form spontaneously by increasing the NaCl concentration (which can be used for developing injectable underwater adhesive formulations). Finally, we demonstrate the ability of these adhesives to release small molecule payloads over multiple-month timescales by characterizing their ability to take up and (open full item for complete abstract)

Committee: Yakov Lapitsky PhD (Committee Chair); Isabel Escobar PhD (Committee Member); Youngwoo Seo PhD (Committee Member) Subjects: Chemical Engineering; Chemistry; Materials Science; Polymer Chemistry; Polymers

Master of Science, Miami University, 2013, Computational Science and Engineering

Treatment of volumetric muscle loss (VML) is a significant challenge in warfighters due to the severity of the injuries usually caused by improvised explosive devices (IEDs), to which there are currently few viable clinical treatment options. Keratin hydrogels offer a potential solution to this problem as carriers of cells and growth factors. Human epithelial keratins are the intermediate structural proteins in cells and can be extracted from several sources including human hair. Their intrinsic characteristics, such as high levels of cysteine residues and resulting disulfide bonds, make them candidates for biomaterial-based carriers of growth factors and cells. We hypothesized that the formulation hydrogels composed of two forms of keratin (keratose that lacks disulfide bonds and kerateine that contains disulfide bonds) could be used to tailor their degradation profiles. Such control over degradation is important in tissue engineering approaches to allow for growth factor release, provide for cell delivery, and ultimately allow for tissue regeneration. In this work, we assessed both material properties of (e.g. rheology, degradation, and protein release) and biological response (e.g. cell viability) to keratin hydrogel formulations of keratose-kerateine mixtures. The results of this thesis work indicate that modulation of intrinsic mechanical properties of the hydrogel will allow spatiotemporal drug and cell delivery that may ultimately promote skeletal muscle regeneration.

Committee: Justin Saul PhD (Advisor); Lei Kerr PhD (Committee Member); Jessica Sparks PhD (Committee Member) Subjects: Biomedical Engineering; Chemical Engineering; Materials Science

PhD, University of Cincinnati, 2007, Engineering : Materials Science

This work focuses on the use of temperature responsive gels (TRGs) (polymeric hydrogels with a large temperature-dependent change in volume) for flavor retention at cooking temperatures. Specifically, we have studied a gel with a lower critical solution temperature (LCST) that swells at low temperatures and collapses at high temperatures. In the collapsed state, the polymer acts as a transport barrier, keeping the volatile flavors inside. An encapsulation system was designed to utilize the solution (phase separation) behavior of a temperature responsive gel. The gel morphology was understood and diffusive properties were tailored through morphology manipulation. Heterogeneous and homogeneous gels were processed by understanding the effect of temperature on gel morphology. A morphology model was developed linking bulk diffusive properties to molecular morphology. Flavor was encapsulated within the gel and the emulsifying capability was determined. The capsules responded to temperature similarly to the pure polymer. The release kinetcs were compared to commercial gelatin capsules and the temperature responsive polymer took longer to release. Chemistry was developed following guidelines for the Food and Drug Administration for food use. The food grade crosslinking was coupled with commercial scale-up equipment to develop large scale commercial production procedures. This dissertation resulted in a new commercial encapsulation system. The system is able to tailor release kinetics through processing conditions. New crosslinking methods were developed with the possibility of opening new markets in food, flavor, and fragrance.

Committee: Dr. Dale Schaefer (Advisor) Subjects:

MS, University of Cincinnati, 2006, Engineering : Materials Science

This work focuses on the use of temperature responsive gels (TRGs) (polymeric hydrogels with a large temperature-dependent change in volume) for flavor retention at cooking temperatures. Specifically, we have studied a gel with a lower critical solution temperature (LCST) that swells at low temperatures and collapses at high temperatures. In the collapsed state, the polymer acts as a transport barrier, keeping the volatile flavors inside. We have successfully synthesized a cellulose gel to exhibit this volume change and have encapsulated an oil phase inside the gel. The flavor-loaded encapsulated oil exhibited an increased release time when compared to similar gelatin capsules.

Committee: Dr. Dale Schaefer (Advisor) Subjects: Engineering, Materials Science

PhD, University of Cincinnati, 2003, Pharmacy : Pharmaceutical Sciences

The objective of this project was to study the effect of modifications of endhydroxylated poly(dimethylsiloxane) (PDMS) formulations on tablet drug release. Emulsions of crosslinked endhydroxylated PDMS, a novel film-forming polymer, were characterized and investigated for their ability to be applied onto tablet cores in a spray-coating process for controlled drug release. Modifications of the crosslinking agent from the most commonly used tetraethylorthosilicate (TEOS) to the trifunctional 3-(2,3-epoxypropoxy)propyltrimethoxysilane (SIG) and a 1:1-mixture of the two crosslinker were undertaken. Addition of vermiculate clay, copolymeric substances and different channeling-agents were studied. Copolymers of methylpolysiloxane with polyoxyethylene (DC193 and DC5324) or dimethyl,methyl (polyoxyethylene) (DCQ2-5220) as well as poly (acrylamide-co-acrylic acid) were used. Lactose, microcrystalline cellulose (MCC) and polyethyleneglycol 8000 (PEG) were the channeling-agents applied. A change in molecular weight of the PDMS was analyzed. Effects on dispersion properties were characterized by particle size distribution, viscosity and visual observation of phase-separation. Mechanical properties of resulting cast and sprayed films were studied to determine applicability in a pan-coating process. Release of Hydrochlorothiazide (marker-drug) was studied from tablets coated in a lab-size conventional coating pan. Dispersions were found suitable for a spray-coating process. Only the formulation with acrylic-copolymer addition was unstable as phase separation occurred. Preparation of free films showed that methylpolysiloxane-copolymers negatively affected the mechanical properties so that coating onto tablet cores was not possible. Tablets coated with formulations crosslinked using the 1:1-mixture of SIG/TEOS and containing polyethyleneglycol were most suitable to control drug release, at 5% coating weight. Constant release rates were achieved for formulations with up to 25% (w/w (open full item for complete abstract)

Committee: DR. ADEL SAKR (Advisor) Subjects:

Master of Science, The Ohio State University, 2011, Horticulture and Crop Science

In the first experiment of this thesis, four different fertilizers were applied at three rates each in order to investigate their effect on growth and quality of New Guinea Impatiens (NGI ) (Impatiens hawkeri Bull.) ‘Paradise New Red.' Fertilizer treatments included 1) Peters Peat-Lite 20-4.4-16.6 water-soluble fertilizer (WSF), 2) Daniels 10-1.8-2.5 soybean-based fertilizer (SBF), 3) Osmocote Plus 15-4-10, 3- 4 month longevity controlled-release fertilizer (CRF), 4) and Contec-DG 15-4-10, 5-month slow-release turf fertilizer (AGT). SPAD readings, plant dry weight (DW), consumer preference ratings (CP), and cumulative flower number (CFN) were measured and used to calculate a total quality index and select ‘optimal' application rates for experiment two. SBF applied at equivalent rates of N fertilization resulted in higher dry weight and significantly lower EC than WSF. ‘Optimal' rates were determined to be 1) AGT at 2.14 kg-m-3, 2) CRF at 7.11 kg-m-3, 3) SBF at 150 mg-L-1 N, and 4) WSF at 75 mg-L-1 N. In experiment two, the effect of these ‘optimal' rates on plant growth, nutrition, and nutrient leaching were compared. One or more nutrient deficiencies were detected in every treatment except CRF. While SBF plants appeared healthy, necrotic spotting occurred due to K deficiency. AGT plants were rated the lowest by consumers, grew the least, had lower SPAD, and were generally less floriferous than other treatments. CRF leached the most nutrients, most notably N (94-524% more total N), especially early in the production period. N, P, K, and Mg losses were the most affected by leaching with clear water to reduce supraoptimal substrate EC. While SBF leached similar amounts of N as WSF even though it was fertigated at twice the rate, higher N leaching may have occurred due to unmeasured urea in leachate. Based on these results, three-month longevity CRF and AGT may not be suitable for NGI fertilization. In experiment three, the effect of temperature on nutrient leaching at (open full item for complete abstract)

Committee: Claudio C. Pasian (Advisor); Jonathan M. Frantz (Committee Member); Michelle L. Jones (Committee Member) Subjects: Horticulture

Doctor of Philosophy, The Ohio State University, 2010, Chemical and Biomolecular Engineering

Since axons do not regenerate appreciably in their native extracellular environment in the central nervous system (CNS); some researchers tried to help patients to restore their lost neural function by integrating prosthetics with their nervous system. However, achieving stable, long-term performance of implanted neural prosthetic devices has been challenging because of implantation related neuron loss and a foreign body response that results in encapsulating glial scar formation. To improve neuron-prosthesis integration and form chronic, stable interfaces, we investigated the potential of neurotrophin-eluting hydrogel-electrospun fiber mat (EFM) composite coatings. We first synthesized and characterized diacrylate poly(ethylene glycol)-poly(ε-caprolactone) (PEGPCL) and poly(ethylene glycol)-poly(lactic acid) (PEGPLA) block copolymers as hydrogel materials. Then, we fabricated and evaluated poly(ε-caprolactone) (PCL) EFMs with different thicknesses and hydrophobicity. Followed, we constructed PEGPCL hydrogel-PCL EFM composite materials in two different configurations using UV photo-polymerization, and compared the release kinetics of these composites using bovine serum albumin (BSA) as a model protein. The aggregation status and bioactivity of eluted proteins were also investigated. To better understand the interaction between the eluted protein and composite material, PEGPLA hydrogel-EFM composite materials were formed, comprising of EFMs with different thicknesses and hydrophobicity. The results of composite materials' swelling and release behaviors demonstrated that both EFM's thickness and hydrophobicity had significant impact on therapeutics release profile. In addition, we studied the cell adhesion of SK-N-SH neuroblastoma cells and rat cortical cells to hydrogel-EFM composite materials. The incorporation of external EFMs significantly enhanced cell attachment on composite materials, when compared with PEG and PEGPCL hydrogels. And RNCs preferred to adhere (open full item for complete abstract)

Committee: Jessica O. Winter (Advisor); John J. Lannutti (Committee Member); Jeffrey J. Chalmers (Committee Member) Subjects: Biomedical Engineering; Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2010, Horticulture and Crop Science

A liner refers to a small plant that is transplanted and grown to become larger. Tree liners are typically produced in the Pacific Northwest of the United States. Even though the Midwestern US has a shorter growing season, many advantages of producing tree liners in retractable roof greenhouses (RRG) in the US Midwest have been previously found. A production system at The Ohio State University (OSU), Columbus, Ohio, using a RRG (Cravo Equipment, Ltd., Bradford, ON, Canada) and containerized tree liner production with or without out planting to pot in pot (PIP) was evaluated in this dissertation. Bottom heat (BH) mats (Olson Products Inc., Medina, Ohio) used for Fall 2007 plantings at 40°F did not affect the growth of trees when compared to plants at ambient temperature (AT). BH treatment for Fall 2008 plantings at 70°F used during winter promoted the height and caliper of red maple (Acer rubrum L. ‘October Glory'®) and Avondale red bud (Cercis chinensis L. ‘Avondale'). Avondale redbud continued to show benefits of BH even 20 months after application in the RRG. Littleleaf linden (Tilia cordata Mill. ‘Greenspine'®) had a better growth in AT than BH. Red maples and littleleaf linden, planted in Fall, showed larger heights and calipers than those planted in Summer due to better acclimation. Fertilizer treatments were used on the first year with either a top dressing of controlled release fertilizer 40g of 19N-2.2P-6.6K (19-5-8, Osmocote Pro with minors, 8-9 months, Scott's Co.), or a top dressing of 20g of CR supplemented with liquid fertilizer (LF), 400 ppm of 21N-3.1P-5.9K (21-7-7, Scott's Company, Marysville, Ohio), via a fertilizer injector (Dosatron®, Clearwater, Florida) once every two weeks (CR+LF treatment). Fall 2007 plantings with CR+LF produced larger caliper for red maple and taller Avondale redbuds. Littleleaf lindens were not affected by the fertilizer treatments in Fall 2007. Summer 2008 plantings had bigger height and caliper with CR for red maple and (open full item for complete abstract)

Committee: Hannah Mathers PhD (Advisor); Daniel K. Struve PhD (Committee Member); Robert C. Hansen PhD (Committee Member); Rebecca S. Lamb PhD (Committee Member) Subjects: Horticulture