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You searched for +publisher:"Clemson University" +contributor:("Jason D McNeil"). Showing records 1 – 2 of 2 total matches.

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Clemson University

1. Uzair, Unaiza. A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging.

Degree: PhD, Chemistry, 2020, Clemson University

Implant-associated infection is a leading cause of fixation failures and these infections are resistant to antibiotics especially after mature biofilms have been established on the implant surface. These infections can also be challenging to detect, especially at early stages or during antibiotic treatment, due to lack of symptoms and specific tests to detect localized infection. Low pH is believed to be associated with infection as bacteria and inflammatory responses can cause a pH drop in the affected area. Detecting changes in pH on the implant surface can provide a better understanding and help to detect, treat and monitor such infections more effectively thereby reducing the need for revision surgeries. We developed a novel X-ray Excited Luminescence Chemical Imaging (XELCI) technique to measure surface specific chemical concentrations with sub-millimeter spatial resolution. A focused X-ray beam (~0.3 mm) passes through tissue and irradiates scintillators coated on an orthopedic implant; these scintillators generate visible and near infrared light which is partially absorbed by a pH indicator film (e.g., bromocresol green or bromothymol blue pH dye encapsulated in a PEG hydrogel) altering the luminescence spectrum in a pH-dependent manner. Images are acquired by scanning the beam point-by-point and measuring the spectrum at each point. We developed, synthesized and tested pH indicator films and measured the signal intensity, noise level, and knife-edge spatial resolution through varying thicknesses of chicken breast tissue and through 11 mm of human cadaveric tissue in a tibial fixation specimen. For example, we observed a knife-edge (80/20) spatial resolution of ~0.5 mm through up to 1 cm of tissue and an average pH noise level of 0.25 ±0.05 pH units. We also implanted the pH sensor in rabbits to image pH during infection. The in vivo studies found that the sensors continued to function well for the 11-day experiments. During infection, the pH did not significantly drop compared to uninfected implants on opposite legs (<0.5 pH unit change). For sensors that were initially acidic and infected, the pH neutralized in time, and this neutralization could be delayed by enclosing the implant in cavity with a 1 mm aperture to slow perfusion and diffusion. These studies show applicability provide useful insight into the pH changes that occur on implant surface during infection and can have important implications for antibiotic treatments. Future directions include improving the collection efficiency, adding an X-ray chopper to measure background signal and luminescence lifetime, scanning scintillator nanoparticles in three dimensions for tomography, detecting additional analytes, and studying pH changes on the device surface during infection followed by antibiotic treatment in animal models and to develop a model for pH changes during osteomyelitis. Advisors/Committee Members: Jeffrey N Anker, Tzuen-Rong Tzeng, Stephen Creager, Carlos D Garcia, Jason D McNeil.

Subjects/Keywords: bioimaging; implant associated infection; in vivo pH mapping; pH sensing; X-ray scintillation; XELCI

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Uzair, U. (2020). A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2655

Chicago Manual of Style (16th Edition):

Uzair, Unaiza. “A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging.” 2020. Doctoral Dissertation, Clemson University. Accessed December 05, 2020. https://tigerprints.clemson.edu/all_dissertations/2655.

MLA Handbook (7th Edition):

Uzair, Unaiza. “A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging.” 2020. Web. 05 Dec 2020.

Vancouver:

Uzair U. A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging. [Internet] [Doctoral dissertation]. Clemson University; 2020. [cited 2020 Dec 05]. Available from: https://tigerprints.clemson.edu/all_dissertations/2655.

Council of Science Editors:

Uzair U. A pH Sensor for Non-Invasive Detection and Monitoring of pH Changes During Implant-Associated Infection Using X-ray Excited Luminescence Chemical Imaging. [Doctoral Dissertation]. Clemson University; 2020. Available from: https://tigerprints.clemson.edu/all_dissertations/2655


Clemson University

2. Wan, Wang. Main Group Element-containing Chromophores and Polyelectrolytes: Sulfur, Phosphorus and Gallium.

Degree: PhD, Chemistry, 2018, Clemson University

Research on chromophores and polyelectrolytes incorporating main group elements has attracted tremendous research interest and been investigated extensively in the past few decades. In the current contribution, potential applications of polyelectrolytes in ion-conductive/exchange materials, optoelectronics and as antibacterial agents are studied systematically. Several new classes of chromophores based on heterocycle (thiophene and pyrrole) motifs have been developed in this work, with potential use in various areas including organic photovoltaics, organic light-emitting diodes, chemical/bio-sensors, bio-imaging/labeling, etc. In Chapter 2, a series of ten polythiophene derivatives is discussed. Each polymer in the series has a different percentage of carboxylic acid-bearing repeat units. The properties of these polymers are explored under neutral and anionic forms. The properties that are examined include UV-vis absorption and photoluminescence spectroscopy of films and solutions as well as solution aggregation measured by dynamic light scattering. All of these properties are strongly dependent both on protonation state and percentage of carboxylic acid/carboxylate side chains along the polymer backbone. The anionic form of each polythiophene derivative was then employed for layer-by-layer (LbL) film deposition with a cationic phosphonium polyelectrolyte. The film growth process is studied by spectroscopic techniques and film morphologies are examined by atomic force microscopy. In Chapters 3 and 4, two series of tetraarylphosphonium polyelectrolytes (TPELs) has been discussed. This work involved developing new polymerization protocols for using commercial diphenylphosphine and dihalides or readily-prepared bis(aryl triflate)s as monomers. The Ni- and Pd-catalyzed P–C coupling formation reactions produce degrees of polymerization up to 65. All TPELs have reasonable thermal stability in the range of 350-450 °C. The stability of the TPELs to alkaline solution is strongly depend on the spacer between adjacent phosphonium sites as well as counterions. The work presented in Chapter 5 shows design and synthesis of two series of phosphonium polyelectrolytes (PELs) analogues. The polymerizations of diphosphines and α,α′-dibromo-p-xylene via SN2 reaction yielded phosphonium polymers with the degrees of polymerization higher than 10. The prepared polymers were employed for LbL self-assembly fabrication. The influences depending on spacer between charged sites and existence of hydrophobic side-chains have been investigated and compared systematically. The Chapter 6 presents the work on a heavier analogue of BODIPY dye which presents strong visible light absorption and fluorescence emission. The new type of fluorescent dye has been prepared successfully with moderate yield ~ 44.2%. These new dyes exhibit strong visible light absorption and fluorescence emission (quantum yield up to 90 %). One member of this new chromophore family has been characterized by single crystal X-ray… Advisors/Committee Members: Rhett C Smith, Andrew G Tennyson, Jason D McNeil, Daniel C Whitehead.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wan, W. (2018). Main Group Element-containing Chromophores and Polyelectrolytes: Sulfur, Phosphorus and Gallium. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2407

Chicago Manual of Style (16th Edition):

Wan, Wang. “Main Group Element-containing Chromophores and Polyelectrolytes: Sulfur, Phosphorus and Gallium.” 2018. Doctoral Dissertation, Clemson University. Accessed December 05, 2020. https://tigerprints.clemson.edu/all_dissertations/2407.

MLA Handbook (7th Edition):

Wan, Wang. “Main Group Element-containing Chromophores and Polyelectrolytes: Sulfur, Phosphorus and Gallium.” 2018. Web. 05 Dec 2020.

Vancouver:

Wan W. Main Group Element-containing Chromophores and Polyelectrolytes: Sulfur, Phosphorus and Gallium. [Internet] [Doctoral dissertation]. Clemson University; 2018. [cited 2020 Dec 05]. Available from: https://tigerprints.clemson.edu/all_dissertations/2407.

Council of Science Editors:

Wan W. Main Group Element-containing Chromophores and Polyelectrolytes: Sulfur, Phosphorus and Gallium. [Doctoral Dissertation]. Clemson University; 2018. Available from: https://tigerprints.clemson.edu/all_dissertations/2407

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