Thesis (Ph.D)--Aerospace Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Hanagud,Sathya; Committee Member: Apetre, Nicoleta; Committee Member: Kardomateas, George; Committee Member: McDowell, David L.; Committee Member: Ruzzene, Massimo. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains vi, 113, 30 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 112-113).

Thesis (M.S. in civil engineering)--Washington State University, May 2010. / Title from PDF title page (viewed on June 16, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 82-89).

The increase and change in traffic loading in recent years has resulted in the introduction of a new range of high performance asphalt binders. These new binders known as modified asphalt binders, have a more complex behavior than traditional binders. A review of the current mathematical models shows that most of them suffer from different drawbacks that make them inadequate for their intended application. To describe the behavior of straight and modified binders in the thermorheologically simple linear viscoelastic region, two models are proposed. Models to characterize the absolute value of the complex shear modulus (|G*|) and the phase angle (d) were developed using the matching function approach and validated by an experimental program. The dynamic mechanical properties of two typical paving grade binders and three modified binders were tested at intermediate and high service temperatures. Short-term and long-term aging were simulated by the rolling thin film oven test and the pressure aging vessel test, respectively. A dynamic shear rheometer with parallel plate configuration was used to conduct the dynamic mechanical tests at frequencies between 0.06 to 188.5 rad/sec and temperatures ranging from 5 to 75°C. Prior to the frequency sweeps, strain sweeps were performed to establish the linear viscoelastic region. Results indicated a strong susceptibility to the defined strain at intermediate temperatures; however, strain susceptibility was less pronounced at high temperatures. Frequency sweeps were then conducted at a constant strain corresponding to greater than 95% of the initial complex shear modulus as established by AASHTO TP5 for straight asphalts. The Time-Temperature Superposition Principle was used to construct the master curves. The shift factors were determined based on the complex shear modulus master curves and verified for the phase angle, storage shear modulus and loss shear modulus. After construction of the master curves, non-linear regression was used to fit the proposed models to the experimental data. Comparison between the measured and predicted values indicated a good agreement for frequencies higher than 10⁵ rad/sec. The phase angle model was found to adequately describe unmodified binder with a small percentage of errors (less than 6%). On the other hand, the phase angle model was found unable to simulate the plateau region observed for polymer-modified binders. However, the error in this case was found to be relatively small (from zero to 10%). The ability of the models to estimate other viscoelastic functions, e.g. storage shear modulus (G'), loss shear modulus (G"), and relaxation spectrum (H(t)), was found to be adequate. / Master of Science

DNA photosensitizers are compounds that are capable of binding in to DNA strands through groove binding, intercalation, or electrostatic interactions. Excitation of these agents by light generates reactive oxygen species which causes extensive photo-oxidative damage to genomic DNA. Physiological concentrations of NaCl and KCl are ~ 150 mM and 260 mM within the cell nucleus where DNA is contained. Unfortunately, the ability of most photosensitizers to bind to double-helical DNA is reduced and photocleavage yields are diminished as concentrations of salt increase. The aim of this project is to observe the photocleavage of pUC19 plasmid DNA induced by N1,N1-bis(9-anthrymethyl)triethylenetetraamine tetrahydrochloride (AL-VIII 23) 1 or N,N-dimethyl-N’-(9-methylanthracenyl)ethylenediamine (NMEA) 2 in presence of salt. Spectroscopic titrations and DNA melting assays were used to study binding modes and affinities of both dyes to the helix upon the addition of salt.

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains viii, 106 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 104-105).

No description available.

Published Article / Titanium has fired the imagination of engineers and designers for decades by its 'ideal' combination of high strength, low density and good corrosion resistance. However, its application has unfortunately been limited to those niche markets where performance is more important than cost, such as in the aerospace, military, medical and off-shore oil drilling fields. Extensive efforts have been and still are being expended on ways to make this metal cheaper. There are promising new processes but these have yet to be demonstrated commercially. Nevertheless, there has been a global surge in interest in titanium over the past decade, and in South Africa the government has recently made this a particular focus for research and development funding. With the increased availability of higher quality titanium powder, metal injection moulding offers an attractive method for producing small, intricate components at a reasonable cost. This paper will present an overview of the metal injection moulding process and discuss the particular challenges related to the use of titanium and titanium alloy powders. The state of the global and local industry and markets will also be reviewed.

Thesis advisor: Jianmin Gao / Thesis advisor: Eranthie Weerapana / Nature has developed a generous number of peptides carrying out various essential functions in all living organisms. Human body produces peptides as signaling molecules, such as hormones, to transmit messages from cell to cell and regulate metabolic homeostasis. Microbes synthesize peptides as antibiotics to inhibit the growth of other microorganisms. These peptides display an exceeding diversity of amino acid composition, peptide sequence, secondary structure and post-translational modification. Inspired by nature, researchers have developed peptides as a unique modality of therapeutics, combining the best attributes of small-molecule drugs and protein-based biopharmaceuticals. This work has sought to explore the potential of peptides as synthetic receptors, binders of protein and probes for bacteria detection. The research started from a foldable cyclic peptide scaffold, prolinomycin, a proline-rich analogue of valinomycin. The peptide can chelate a potassium ion folding into a drum like structure, which provides a platform to display and preoganize functional side chains for target binding. We first investigated its folding behavior under physiological conditions. We demonstrate that the metal-assisted folding of the prolinomycin scaffold tolerates various side chain mutations. The stability of the structure can be improved by introducing crosslinking moieties. Based on this scaffold, we rationally designed synthetic receptors of various amines by utilizing iminoboronate chemistry with acetylphenyl boronic acid (APBA). Furthermore, I pursued phage display, a powerful technique to develop high affinity peptide binders of protein targets. Proteins are the most appealing targets for drug development and disease biomarkers discovery. We chose sortase A (SrtA) as a model target protein to screen for potent peptide binders. A peptide inhibitor of sortase A with single-digit micromolar affinity was identified from a cyclic peptide library displayed by phage. In addition, from the chemically modified phage display peptide library presenting APBA motifs, peptide binders with specificity and micromolar affinity towards SrtA were discovered. Instead of binding to the active site, the peptide could recognize the surface of the protein. Additionally, to further expand the chemical space of phage display, I constructed a phage display peptide library presenting N-terminal cysteine (NCys) which can undergo site-specific chemical modifications. Two pieces of chemistry were applied, including thiazolidino boronate (Tzb) mediated acylation reaction of NCys and 2-cyanobenzothiazole (CBT)-NCys condensation. The site-specific dual modifications on NCys and internal Cys of phage-encoded peptides were achieved. Furthermore, a strategy to N, S-doubly label NCys via an alternative pathway of CBT condensation was reported, which presents a significant addition to the toolbox for site-specific protein modifications. Finally, by functionalizing graphene field effect transistors (G-FET) with peptide probes, we developed the first selective, electrical detection of the pathogenic bacterial species Staphylococcus aureus and antibiotic resistant Acinetobacter baumannii on a single platform. Overall, peptides provide enormous opportunities for therapeutics development. Research herein demonstrated principles of peptide design for specific molecular recognition. Novel chemistry strategies have been developed to expand the molecular diversity of peptide libraries. We believed that the advances in peptide design and screening would promote peptide-based drug discovery. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Mycotoxins are feed contaminants that are a major problem in the livestock industry because of their prevalence in feedstuffs and the difficulty of removing them. They can cause a wide range of issues at varying levels of exposure. Each species is affected by different mycotoxins and at different levels. Pigs are more susceptible to deoxynivalenol (DON), whereas ducks are more susceptible to aflatoxin.<br> Effects of mycotoxin contamination on animal performance are not fully understood. Therefore, the two experiments described in this thesis were conducted to determine the response of pigs and ducks to consumption of feed contaminated with DON and aflatoxin, respectively. In the first experiment, the effect of a mycotoxin binder on duck feeds contaminated with aflatoxin was examined. One-day-old male Pekin ducks (n=360) were randomly divided into four groups; each group had 6 replicate pens with 15 ducks per replicate pen. The positive control (PC) group was fed a diet that was free of aflatoxin B1, the negative control (NC) group was fed a diet that contained >75ppb of aflatoxin without a binder, the negative control with low binder (NC + 0.5) group was fed a diet that contained >75ppb of aflatoxin and 0.5 kg/ton of the binder, the negative control with high binder (NC + 1.0) group was fed a diet that contained >75ppb of aflatoxin and 1.0 kg/ton of the binder. The diets were fed in two phases, days 0-14 (phase 1) and 15-35 (phase 2). The results showed that during early phase 2, NC + 0.5 resulted in a higher rate of weight gain compared to NC (P<0.05); 2) NC + 0.5 ducks had higher feather quality than both NC and PC (P<0.05); 3) NC had higher relative liver weights (P<0.05); 4) blood glucose was higher in NC + 0.5 ducks (P<0.05); and 5) PC ducks had higher serum protein levels in the blood (P<0.05).<br> In the second study, effect of the same mycotoxin binder, used in the duck study, was examined in pigs fed diets contaminated with DON. A total of 128 pigs (Duroc × Landrace × Yorkshire, (1:1 barrows and gilts, aged 42 d) were randomly assigned to 4 treatments, 8 replicate pens with 4 pigs per. The treatments were DON, DON + liver protectant (1 kg/ton), DON + mycotoxin binder (0.5 kg/ton), or DON + liver protectant and mycotoxin binder. The study lasted 28 days and body weights (BW), feed intake (FI), and blood samples were taken on days 14 and 28. Body weights and feed intake were taken and used to calculate gain:feed (G:F). Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured in the blood serum. BW, FI, and G:F were not significantly different at any point during the study. AST levels were significantly reduced (P < 0.05) on day 14 in pigs fed the liver protectant but were not significantly different day 28.<br> In summary, effects of the use of mycotoxin binders in feed can be highly variable. This depends on the type of mycotoxin present in the feed, the amount of mycotoxin, and the species fed the diet. In the present study, the mycotoxin binder did not have an impact on the feed efficiency of the ducks or pigs. Effects of additional binders need to be evaluated for their effectiveness in mitigating the negative effects of mycotoxins.<br><br>