Yes / Peptide-mediated synthesis and assembly of nanostructures opens new routes to functional inorganic/organic hybrid materials. However, understanding of the many factors that influence the interaction of biomolecules, specifically peptides, with metal surfaces remains limited. Understanding of the relationship between peptide sequence and resulting binding affinity and configurations would allow predictive design of peptides to achieve desired peptide/metal interface characteristics. Here, we measured the kinetics and thermodynamics of binding on a Au surface for a series of peptide sequences designed to probe specific sequence and context effects. For example, context effects were explored by making the same mutation at different positions in the peptide and by rearranging the peptide sequence without changing the amino acid content. The degree of peptide-surface contact, predicted from advanced molecular simulations of the surface-adsorbed structures, was consistent with the measured binding constants. In simulations, the ensemble of peptide backbone conformations showed little change with point mutations of the anchor residues that dominate interaction with the surface. Peptide-capped Au nanoparticles were produced using each sequence. Comparison of simulations with nanoparticle synthesis results revealed a correlation between the colloidal stability of the Au nanoparticles and the degree of structural disorder in the surface-adsorbed peptide structures for this family of sequences. These findings suggest new directions in the optimization and design of biomolecules for in situ peptide-based nanoparticle growth, binding, and dispersion in aqueous media.

The purpose of this investigation was to compare the frequencies of normal and abnormal findings from exercise electrocardiography (ECG) and post-exercise echocardiography (ECHO) studies in a series of hypertensive and normotensive individuals who underwent diagnostic testing. Data for the ECG and ECHO variables were obtained simultaneously in association with treadmill exercise studies. Eighty consecutive cases were included in this retrospective study. Records were excluded if patients had: history of myocardial infarction; valvular heart disease; ECG evidence of abnormal Q waves, left ventricular hypertrophy (LVH) with abnormal ST/T wave pattern, or left bundle branch block (LBBB); medications that would alter blood pressure responses or ECG interpretation; technically uninterpretable records; or failure to attain 85% of age-adjusted maximal heart rates in the exercise tests. Subjects were defined as hypertensive (HYP) if any one of the following criteria were met: 1) SBP ≥ 140 mmHg or DBP ≥ 90 mmHg; 2) current use of antihypertensive medications; or 3) history of hypertension. Normotensive subjects (NORM) were defined as absence of the above criteria. In each test, ECG data were taken at peak exercise, and ECHO data were taken immediately post-exercise (~ 45 sec). The ECG response was considered abnormal if the ST shifted ≥ 0.1 mV from baseline at J₆₀ while the ECHO response was considered abnormal when new or worsening of pre-existing wall motion abnormalities was observed. Chi square analysis demonstrated that high blood pressure status Significantly increased the frequency of clinically abnormal findings with ECHO (X²=9.15; p ≤ 0.01). This was not the case for exercise ECG (X²=2.12; p > 0.05). However, there waS no Significant difference in the frequency of normal findings when comparing the two testing methods for both subject groups. These results indicate that resting blood pressure status may influence the rate of occurrence of abnormal vs normal ECG and ECHO findings; these data warrant further evaluation studies with invasive criterion measures of CAD status. / Master of Science

No description available.

published_or_final_version / Physiology / Doctoral / Doctor of Philosophy

Effective design of liquid fuel injection systems is a function of good understanding of liquid breakup mechanisms. A transient liquid breakup model is developed on the classical interfacial breakup theory by modifying the classical linear perturbation process to include time-dependent base and perturbed flow parameters. The non-isothermal condition on liquid jet instability and breakup is theoretically modelled; with the particular consideration of a spatially variation of surface tension along the liquid-gas interface. The model combines the classical interface hydrodynamic instability and breakup theory and heat-transfer through semi-infinite medium. Analytical liquid breakup model, which combines transient and non-isothermal effects on liquid jet breakup, is suggested. The suggested model could be simplified to the transient breakup model and the non-isothermal breakup model equivalents. A novel mechanistic model, which is based on a simple momentum balance between the injected jet and the aerodynamic drag force, is suggested for breakup length. A new model, which combines energy criterion and dual-timescale for turbulent shear in droplet dispersion, is suggested for droplet breakup criteria on the basis of critical Webber number. All developed models showed good predictions of available experimental data, and established empirical correlation, within the operational conditions of contemporary ICEs, specifically diesel engines. Continued research in these areas could benefit the development of the next generation of liquid fuel injectors and combustors – by accounting for transient effects and non-isothermal conditions in liquid jet breakup, and turbulent shear in droplet breakup.

This paper studies the effect of same-sex teachers on students attending Economics A at Uppsala University from 2013 to 2018. Having a female teacher has no significant effect on female students’ exam performance but a significant and positive effect on the likelihood of attending the subsequent course in Economics. Certain types of female teachers have negative effects on male students’ exam performance in certain specifications and no effect on the likelihood of them attending the subsequent course. It was not possible to identify the underlying mechanism behind these results.

Abstract will not load on to DSpace

A thesis submitted to the Faculty of Medicine, University of the Witwatersrand, for the degree of Doctor of Philosophy in Medicine. / Despite having been initially described more than fifty years ago, sclerotherapy of oesophageal varices has only relatively recently became regarded as one of the primary modalities both to control bleeding oesophageal varices and to prevent recurrent bleeding. Sclerotherapy, however, ts associated with numerous complications and its exact mechanism of action, particularly that pertaining to its effect on haemostasis, has to date been poorly documented. One of the problems of comparing the various trials has been the diversity of both the technique and the type and concentration of the sclerosants used. (Abbreviation abstract) / Andrew Chakane 2018

Estudos sugerem que a suplementação de creatina pode atenuar a resistência à insulina, embora sejam escassas evidências que atestem a segurança desse suplemento. Diante disso, esse estudo teve como objetivo investigar a eficácia e segurança da suplementação de creatina em diabéticos do tipo 2. Foi conduzido um estudo clínico, randomizado, duplo-cego, controlado por placebo. Ao longo de três meses, os pacientes foram submetidos a treinamento físico e suplementação de creatina (CR) ou placebo (PL). No período basal e após a intervenção, os indivíduos realizaram avaliações de controle glicêmico, perfil lipídico, capacidade física, composição corporal e efeitos adversos. Além disso, os voluntários foram submetidos à biópsias musculares, para análises da expressão proteica e translocação de GLUT-4, e espectrometria de fósforo para determinação dos conteúdos intramusculares de fosforilcreatina. Após a intervenção, as concentrações intramusculares de fosforilcreatina foram maiores no grupo CR (diferença estimada entre as médias: 23,6 mmol/Kg músculo úmido; p = 0,03). Esse grupo também apresentou menores concentrações de hemoglobina glicada quando comparado ao grupo PL (diferença estimada entre as médias: -1,1%; p = 0,004). Os testes de tolerância oral à refeição demonstraram menores valores de glicemia de jejum e pós-prandial (momentos 30 e 60 minutos) no grupo CR versus PL. A expressão proteica de GLUT-4 não foi diferente entre os grupos, porém o aumento na translocação dessa proteína foi significantemente superior no grupo CR (p = 0,03). Não houve diferenças significantes entre os grupos para a insulinemia, perfil lipídico, concentrações séricas de peptídeo C, composição corporal, condicionamento aeróbio, força e função musculares. A suplementação de creatina não provocou deterioração nas funções renal e hepática. Os demais efeitos adversos relatados também não foram diferentes entres os grupos. Desta forma, concluímos que a suplementação de creatina aliada ao treinamento físico é uma estratégia terapêutica segura e efetiva em melhorar o controle glicêmico em diabéticos do tipo 2. Número de registro no domínio Clinicaltrials.com: NCT00992043 / Some studies have suggested that creatine supplementation may attenuate insulin resistance, but whether this supplement is safe remains uncertain. In light of this, the aim of this trial was to investigate the efficacy and safety of creatine supplementation combined with exercise training in patients with type II diabetes. A randomized, double-blind, placebo-controlled, clinical trial was conducted. The patients were submitted to exercise training and received either creatine (CR) or placebo (PL) for 12 weeks. At baseline and after the intervention, glycemic control, lipid profile, physical capacity, body composition, and adverse effects were assessed. Moreover, muscular biopsies were performed to determine the muscle GLUT-4 content and the GLUT-4 translocation, and muscle phosphorylcreatine was assessed by using magnetic resonance spectroscopy. After the intervention, muscle phosphorylcreatine content was higher in the CR group (estimated difference of means: 23.6 mmol/Kg wet muscle; p = 0.03). The CR group also presented decreased glycosylated hemoglobin when compared to the PL group (estimated difference of means: -1.1%; p = 0.004). The oral meal tolerance tests revealed reduced fasting and postprandial glycemia (30 and 60 minutes) in the CR versus the PL group. The muscle GLUT-4 content was similar between groups, but the increase in GLUT-4 translocation was significantly superior in the CR group when compared to the PL group (p = 0.03). In addition, No significant differences between groups were observed for insulinemia, lipid profile, serum peptide C concentration, body composition, aerobic conditioning, strength, and muscle function. Cr supplementation provokes no deleterious effects on kidney and liver functions. The reported adverse effects were similar between groups. Thus, we concluded that creatine supplementation is safe and capable of improving glycemic control in type 2 diabetic patients. ClinicalTrials.gov registration number: NCT00992043

Teachers and schools both play important roles in students' education. Yet, the unique contribution of each to students' growth has rarely been explored. In this dissertation, a Bayesian multilevel model was applied in each of Grades 3 to 5, with students' growth estimated across three seasonal (fall, winter, spring) administrations of a mathematics assessment. Variance in students' within-year growth was then partitioned into student-, classroom-, and school-level components. The expected differences in students' growth between classrooms and schools were treated as indicators of the teacher or school "effect" on students' mathematics growth. Results provided evidence that meaningful differences in students' growth lies both between classrooms within schools, and between schools. The distribution of teacher effects between schools was also examined through the lens of access and equity with systematic sorting of teachers to schools leading to disproportional student access to classrooms where the average growth was above the norm. Further, previous research has documented persistent and compounding teacher effects over time. Systematic teacher sorting results in students' having differential probabilities of being enrolled in multiple "high" or "low" growth classrooms in a row. While clear evidence of teacher sorting was found, the demographic composition of schools did not relate to the sorting, contrary to previous research. The persistence of teacher and school effects was also examined from a previously unexplored angle by examining the effect of students' previous teacher(s) on their subsequent rate of within-year growth during the school year. These effects were found to be small and teacher effects overall were found to decay quite rapidly.