Doctor of Philosophy

dissertationThe development of techniques to probe molecular transport and the dynamics of molecular interactions at interfaces is important for understanding and optimizing surface-based technologies including surface-enhanced spectroscopies, biological assays, sensors, catalysis, and chemical separations. In particular, the efficiency and resolution of separation via reversed-phase liquid chromatography is governed by the interaction of analytes with the solution/stationary phase interface. Most commonly, the stationary phase material consists of high surface area, micron-sized, mesoporous silica particles functionalized with n-alkane ligands. Understanding the timescales at which analyte molecules are transported through the interior of the particle, as well as adsorbed and desorbed from the particle surface, is of fundamental importance in the development of new, more efficient chromatographic materials. Probing chemical interactions at interfaces is difficult due to the selectivity needed to measure the small population of molecules at an interface versus bulk solution. Measuring interfacial chemical interactions within chromatographic particles has the added challenge that the majority of the surface area is contained within the particle making it difficult to measure interfacial processes directly. In this work, single-molecule spectroscopic techniques are used to measure the transport and adsorption/desorption kinetics of molecules at planar reversed-phase chromatographic interfaces and within reversed-phase chromatographic particles. Fluorescence imaging with single-molecule tracking is used to track the locations of fluorescent molecules during their retention within chromatographic particles. This yields information regarding their diffusion rates and their residence time within the particle. Statistical criteria based on the single-molecule localization resolution are also developed to characterize the population of strongly adsorbed molecules and their effect on intraparticle molecular residence times. Fluorescence imaging is also combined with fluorescence-correlation spectroscopy and used to measure fast interfacial transport and sorption kinetics at planar models of chromatographic interfaces. This technique has higher temporal resolution relative to imaging and is capable of measuring transport approaching free solution diffusion rates of small molecules. Finally, a comparison is made between interfacial transport rates and surface populations measured at planar chromatographic interfacial models versus within porous particles. It is found that n-alkyl modified planar interfaces are reasonable models for reversed-phase chromatographic particles with proper interpretation of measured parameters

The Importance of Teacher Behavior in Increasing Student Success: Are Teachers Prepared to Meet the Needs of Students with Emotional or Behavioral Disorders?

Despite the dissemination of specific instructional practices including High Leverage Practices and other pedagogical strategies that are considered fundamental to the success of students with emotional/behavioral disorders, research suggests that many of these practices are occurring in schools at unacceptably low rates. This research-to-practice gap is not a new phenomenon. This paper provides an overview of some of these specific teacher-driven instructional behaviors and the implications of the paucity of their use in schools. In addition, the importance of the role that teacher preparation programs play, and steps that they can take to alleviate the research-to-practice gap are discussed

Increasing Student Engagement Through Opportunities to Respond

The evidence for providing sufficient opportunities for students to respond (OTR) has been established in terms of increasing student engagement while decreasing disruptive behavior. Although proven to be effective, teachers are demonstrating low rates of OTR across all grade levels and instructional content areas. Given the potential benefits of increasing OTR, it is critical that teachers find ways to increase the provision of OTR during instruction. This article will discuss the research behind providing sufficient OTR, examine the rate of OTR teachers are providing in schools in relation to optimal rates suggested by research, and provide strategies for increasing OTR during classroom instruction

Using a Token Economy Combined with a Mystery Motivator for a Student with Autism Exhibiting Challenging Behavior

A common characteristic of students with autism spectrum disorder is difficulty attending to and staying on task in classrooms, which can lead to inappropriate and/or disruptive behavior. Benefits of a token economy have been examined with various individuals but few have examined its effects with children with autism spectrum disorder. This study examined the effectiveness of a token economy combined with a mystery motivator in decreasing inappropriate behaviors displayed by a student with an autism spectrum disorder in a small group setting. Results indicated that the token reinforcement program was effective in decreasing the inappropriate behaviors displayed by the student

An Examination of Response Requirements Associated with Teachers\u27 use of Different Opportunities for Student Response During Instruction

Providing effective instruction that increases the degree to which students are engaged with the instructional content has been identified as a research-based practice in that it is associated with positive academic and behavioral outcomes. One high-leverage practice for engaging students is the provision of opportunities to respond (OTR) during instruction. However, previous research has shown that teachers at every level typically use OTRs at rates far below research-based recommendations. This study adds to the literature by breaking OTRs into verbal, non-verbal, and partner categories to further examine how teachers typically foster student engagement. Across 1095 total observations, OTR rates were observed to be higher than previous research. However, teachers at every level were found to use simple verbal questioning greater than 75% of the of the time they provided an engagement opportunity. A discussion focuses on what this implies for students with verbal deficits and on practical implications and areas for future research

Local anaesthesia for pain control during outpatient hysteroscopy: systematic review and meta-analysis

Objective To compare the effects of different types of local anaesthetic for pain control during outpatient hysteroscopy

Analytic and Numerical Study of Preheating Dynamics

We analyze the phenomenon of preheating,i.e. explosive particle production due to parametric amplification of quantum fluctuations in the unbroken case, or spinodal instabilities in the broken phase, using the Minkowski space $O(N)$ vector model in the large $N$ limit to study the non-perturbative issues involved. We give analytic results for weak couplings and times short compared to the time at which the fluctuations become of the same order as the tree level,as well as numerical results including the full backreaction.In the case where the symmetry is unbroken, the analytic results agree spectacularly well with the numerical ones in their common domain of validity. In the broken symmetry case, slow roll initial conditions from the unstable minimum at the origin, give rise to a new and unexpected phenomenon: the dynamical relaxation of the vacuum energy.That is, particles are abundantly produced at the expense of the quantum vacuum energy while the zero mode comes back to almost its initial value.In both cases we obtain analytically and numerically the equation of state which turns to be written in terms of an effective polytropic index that interpolates between vacuum and radiation-like domination. We find that simplified analysis based on harmonic behavior of the zero mode, giving rise to a Mathieu equation forthe non-zero modes miss important physics. Furthermore, analysis that do not include the full backreaction do not conserve energy, resulting in unbound particle production. Our results do not support the recent claim of symmetry restoration by non-equilibrium fluctuations.Finally estimates of the reheating temperature are given,as well as a discussion of the inconsistency of a kinetic approach to thermalization when a non-perturbatively large number of particles is created.Comment: Latex file, 52 pages and 24 figures in .ps files. Minor changes. To appear in Physical Review D, 15 December 199

Outpatient versus inpatient uterine polyp treatment for abnormal uterine bleeding: randomised controlled non-inferiority study.

OBJECTIVE: To compare the effectiveness and acceptability of outpatient polypectomy with inpatient polypectomy. DESIGN: Pragmatic multicentre randomised controlled non-inferiority study. SETTING: Outpatient hysteroscopy clinics in 31 UK National Health Service hospitals. PARTICIPANTS: 507 women who attended as outpatients for diagnostic hysteroscopy because of abnormal uterine bleeding and were found to have uterine polyps. INTERVENTIONS: Participants were randomly assigned to either outpatient uterine polypectomy under local anaesthetic or inpatient uterine polypectomy under general anaesthesia. Data were collected on women's self reported bleeding symptoms at baseline and at 6, 12, and 24 months. Data were also collected on pain and acceptability of the procedure at the time of polypectomy. MAIN OUTCOME MEASURES: The primary outcome was successful treatment, determined by the women's assessment of bleeding at six months, with a prespecified non-inferiority margin of 25%. Secondary outcomes included generic (EQ-5D) and disease specific (menorrhagia multi-attribute scale) quality of life, and feasibility and acceptability of the procedure. RESULTS: 73% (166/228) of women in the outpatient group and 80% (168/211) in the inpatient group reported successful treatment at six months (intention to treat relative risk 0.91, 95% confidence interval 0.82 to 1.02; per protocol relative risk 0.92, 0.82 to 1.02). Failure to remove polyps was higher (19% v 7%; relative risk 2.5, 1.5 to 4.1) and acceptability of the procedure was lower (83% v 92%; 0.90, 0.84 to 0.97) in the outpatient group Quality of life did not differ significantly between the groups. Four uterine perforations, one of which necessitated bowel resection, all occurred in the inpatient group. CONCLUSIONS: Outpatient polypectomy was non-inferior to inpatient polypectomy. Failure to remove a uterine polyp was, however, more likely with outpatient polypectomy and acceptability of the procedure was slightly lower

Outpatient versus inpatient uterine polyp treatment for abnormal uterine bleeding: randomised controlled non-inferiority study.

OBJECTIVE: To compare the effectiveness and acceptability of outpatient polypectomy with inpatient polypectomy. DESIGN: Pragmatic multicentre randomised controlled non-inferiority study. SETTING: Outpatient hysteroscopy clinics in 31 UK National Health Service hospitals. PARTICIPANTS: 507 women who attended as outpatients for diagnostic hysteroscopy because of abnormal uterine bleeding and were found to have uterine polyps. INTERVENTIONS: Participants were randomly assigned to either outpatient uterine polypectomy under local anaesthetic or inpatient uterine polypectomy under general anaesthesia. Data were collected on women's self reported bleeding symptoms at baseline and at 6, 12, and 24 months. Data were also collected on pain and acceptability of the procedure at the time of polypectomy. MAIN OUTCOME MEASURES: The primary outcome was successful treatment, determined by the women's assessment of bleeding at six months, with a prespecified non-inferiority margin of 25%. Secondary outcomes included generic (EQ-5D) and disease specific (menorrhagia multi-attribute scale) quality of life, and feasibility and acceptability of the procedure. RESULTS: 73% (166/228) of women in the outpatient group and 80% (168/211) in the inpatient group reported successful treatment at six months (intention to treat relative risk 0.91, 95% confidence interval 0.82 to 1.02; per protocol relative risk 0.92, 0.82 to 1.02). Failure to remove polyps was higher (19% v 7%; relative risk 2.5, 1.5 to 4.1) and acceptability of the procedure was lower (83% v 92%; 0.90, 0.84 to 0.97) in the outpatient group Quality of life did not differ significantly between the groups. Four uterine perforations, one of which necessitated bowel resection, all occurred in the inpatient group. CONCLUSIONS: Outpatient polypectomy was non-inferior to inpatient polypectomy. Failure to remove a uterine polyp was, however, more likely with outpatient polypectomy and acceptability of the procedure was slightly lower