A Comparison of Saxophone Mouthpieces Using Fourier Analysis to Quantify Perceived Timbre

The saxophone mouthpiece significantly contributes to the overall timbre of the instrument. Specialized mouthpiece designs employ combinations of chamber shape, facing dimensions, and material to create a potential sound and response for the performer. Also, manufacturers claim that ligatures affect tonal brightness. However, there is a lack of scientific data reflecting the impact of the claimed tonal characteristics of the specified designs on timbre. With the advent of the smartphone application, the spectrum analysis (also known as impedance spectra) resulting from a Fourier Transform has recently become available to a mass audience. This technology is being investigated to quantify timbre color. Thus, the primary focus of this thesis was to investigate the use of acoustic measurement technology available on a smartphone to benefit the performance of the musician. Frequency spectra of 12 different alto saxophone mouthpieces with six different ligature combinations and three tenor mouthpiece clones made of different materials were recorded. Four notes were recorded from each mouthpiece based on the fundamentals of the saxophone. The timbres were compared for brightness by measuring the spectral centroid (SC) and normalized spectral centroid (NSC). Specific mouthpiece characteristics were explained and characterized for their contribution to timbre brightness. This explanation was compared against past research. The physical characteristics of several mouthpieces were measured using X-ray tomography, and the frequency spectra of each were recorded. Resulting spectra were analyzed, compared, and charted to isolate and evaluate the influence of mouthpiece characteristics and ligature characteristics on timbre

Reinforcement of dry spun polymeric fibers by cellulose nanocrystal

This study presents the development of composite polymeric fibers using cellulose nanocrystals (CNCs) as reinforcements. CNCs are a class of low cost, renewable and biodegradable materials with high mechanical properties and customizable surfaces. In this study, CNCs were successfully integrated into various polymeric fibers using the method of dry spinning in efforts to improve the fibers’ tensile strength and modulus. The effects of CNCs on two different polymer systems (cellulose acetate and polyvinyl alcohol) were studied. The surface morphologies, mechanical properties, and interactions between the CNCs and the polymer matrix within the fibers were investigated. The results of the characterizations show significant improvement in the tensile strength and modulus of both the cellulose acetate and polyvinyl alcohol fibers with low dosage of CNCs. The presence of CNCs increased the crystallinity of the polymer matrix. The effects of the high shear rates associated with dry spinning on the alignment and dispersion of the nanocrystals in the different systems were also studied. A micromechanical model was developed using data from both systems for the prediction of the fiber mechanical properties as a function of the alignment of the CNC rods

Cardioprotection by systemic dosing of thymosin beta four following ischemic myocardial injury

Thymosin beta 4 (Tβ4) was previously shown to reduce infarct size and improve contractile performance in chronic myocardial ischemic injury via two phases of action: an acute phase, just after injury, when Tβ4 preserves ischemic myocardium via antiapoptotic or anti-inflammatory mechanisms; and a chronic phase, when Tβ4 activates the growth of vascular or cardiac progenitor cells. In order to differentiate between the effects of Tβ4 during the acute and during the chronic phases, and also in order to obtain detailed hemodynamic and biomarker data on the effects of Tβ4 treatment suitable for use in clinical studies, we tested Tβ4 in a rat model of chronic myocardial ischemia using two dosing regimens: short term dosing (Tβ4 administered only during the first 3 days following injury), and long term dosing (Tβ4 administered during the first 3 days following injury and also every third day until the end of the study). Tβ4 administered throughout the study reduced infarct size and resulted in significant improvements in hemodynamic performance; however, chamber volumes and ejection fractions were not significantly improved. Tβ4 administered only during the first 3 days following injury tended to reduce infarct size, chamber volumes and improve hemodynamic performance. Plasma biomarkers of myocyte injury were significantly reduced by Tβ4 treatment during the acute injury period, and plasma ANP levels were significantly reduced in both dosing groups. Surprisingly, neither acute nor chronic Tβ4 treatment significantly increased blood vessel density in peri-infarct regions. These results suggest the following: repeated dosing may be required to achieve clinically measureable improvements in cardiac function post-myocardial infarction (MI); improvement in cardiac function may be observed in the absence of a high degree of angiogenesis; and that plasma biomarkers of cardiac function and myocardial injury are sensitive pharmacodynamic biomarkers of the effects of Tβ4

Comprehensive Versus Usual Community Care for First-Episode Psychosis: 2-Year Outcomes From the NIMH RAISE Early Treatment Program

The primary aim was to compare the impact of NAVIGATE, a comprehensive, multidisciplinary, team-based treatment approach for first episode psychosis designed for implementation in the U.S. healthcare system, to Community Care on quality of life

Sooty Mangabey Genome Sequence Provides Insight into AIDS Resistance in a Natural SIV Host

In contrast to infections with human immunodeficiency virus (HIV) in humans and simian immunodeficiency virus (SIV) in macaques, SIV infection of a natural host, sooty mangabeys (Cercocebus atys), is non-pathogenic despite high viraemia. Here we sequenced and assembled the genome of a captive sooty mangabey. We conducted genome-wide comparative analyses of transcript assemblies from C. atys and AIDS-susceptible species, such as humans and macaques, to identify candidates for host genetic factors that influence susceptibility. We identified several immune-related genes in the genome of C. atys that show substantial sequence divergence from macaques or humans. One of these sequence divergences, a C-terminal frameshift in the toll-like receptor-4 (TLR4) gene of C. atys, is associated with a blunted in vitro response to TLR-4 ligands. In addition, we found a major structural change in exons 3-4 of the immune-regulatory protein intercellular adhesion molecule 2 (ICAM-2); expression of this variant leads to reduced cell surface expression of ICAM-2. These data provide a resource for comparative genomic studies of HIV and/or SIV pathogenesis and may help to elucidate the mechanisms by which SIV-infected sooty mangabeys avoid AIDS

Noble metal-free cathode and electrolyte materials for low-cost, efficient Li-CO₂ batteries

IIn this dissertation, noble metal-free cathode and electrolyte materials are developed to improve the energy efficiency, capacity, and cycle life of lithium - carbon dioxide (Li-CO₂) batteries. These performance enhancements are achieved by reducing the overpotentials of the carbon dioxide reduction reaction (CDRR) during discharge and the carbon dioxide evolution reaction (CDER) during charge. In Chapter 1, an overview of the Li-CO₂ battery system is provided, including a description of Li-CO₂ electrochemistry, Li-CO₂ battery requirements and challenges, and a summary of prior noble metal-free catalysts reported to date. In Chapter 2, general experimental details are outlined, including the cell design, general materials, and characterization instruments used. In Chapter 3, a nanocomposite of anatase TiO₂ nanoparticles grown onto carbon nanotubes and mixed with carbon nanofibers (TiO₂-NP@CNT/CNF) is employed as a gas diffusion cathode (GDC) in Li-CO₂ batteries to improve CDRR kinetics and cycling stability. In Chapter 4, phenyl disulfide (PDS) is introduced as an Li-CO₂ battery electrolyte additive to allow for homogeneous CO₂ utilization. A reaction mechanism involving the formation of the intermediate S-phenyl carbonothioate (SPC⁻) is proposed and supported with experimental evidence. In Chapter 5, a composite of MoS₂ nanosheets grown onto multi-walled carbon nanotubes and mixed with single-walled carbon nanotubes (MoS₂-NS@MWNT/SWNT) is employed as an efficient Li-CO₂ GDC to reduce CDRR and CDER overpotentials. A mechanism is proposed in which the oxalate intermediate C₂O₄²⁻-Mo⁶⁺S₂⁴⁻ is formed, lowering the energy barrier to Li₂CO₃ decomposition on charge. Finally, in Chapter 6, freestanding vanadium nitride nanowires (VN-NW) are employed as a carbon-free Li-CO₂ GDC. The discharge product morphology is greatly improved compared to that of a control MWNT GDC, leading to reduced charge voltage and improved cycle life. Finally, a summary of all the work carried out in this dissertation and a brief perspective on future Li-CO₂ research is given in Chapter 7.Mechanical Engineerin