Browsing by Subject "Efficacy"
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Item A separate efficacy : the green behaviors of Black men in cities(2019-09-26) Almeida, Elaine Brittany-Simões; Atkinson, LucindaAbstract: As communicators seek to increase and bolster green behaviors throughout society, this paper examines an audience who have been historically left out of the messaging and literature: Black men who reside in cities. Though various theories and methods can predict and drive positive behavior change, at the root of many of these scholarly pursuits is an understanding of one’s efficacy, which is their belief that they can perform a task successfully and that it will yield positive results. As such, this paper uses in-depth interviews with respondents from four large American cities to explore their perceptions of and efficacy in performing green behaviors. A qualitative study was undertaken as to reveal organically occurring themes and perceptions from an audience that has very few qualitative works within this topic. From these interviews three key themes emerged from the respondents: the perceived exclusion from hegemonic green behaviors and identities; their actual efficacy in performing green tasks and why they believe it has been excluded from mainstream definitions; the implications for their cities and communities if Black men and communities are not seen as green. These responses point to need for a reassessment of green behaviors that accurately represents the lived experiences and perceptions of Black men and communities.Item A solid nanoparticle formulation of 4-(N)-docosahexaenoyl 2′, 2′- difluorodeoxycytidine, a compound with potent, broad spectrum antitumor activity(2018-09-13) Valdes Curiquen, Solange Alondra; Cui, Zhengrong; Ghosh, Debadyuti; Williams III, Robert O; Stavchansky, Salomon; Finch, Rick AThe strategy to improve the lipophilicity of gemcitabine by conjugation with a lipid (e.g. docosahexaenoic acid (DHA) or stearoyl acid) allows to prevent the deamination of gemcitabine by cytidine deaminase, main cause of gemcitabine degradation in vivo. In addition, this strategy may confer gemcitabine a strong antitumor activity compared to parental drug. 4-(N)-docosahexaenoyl 2´, 2´-difluorodeoxycytidine (DHA-dFdC) is a novel compound with strong in vitro and in vivo antitumor activity in several cancer models (e.g. pancreatic, breast, leukemia, and lung cancer). However, the toxicity of DHA-dFdC has not been tested in an animal model. In this dissertation, a preclinical short-term toxicity study to evaluate the tolerability of DHA-dFdC was performed in healthy DBA/2 mice. DHA-dFdC showed a dose-dependent toxicity, affecting mainly the spleen. The repeat-dose maximum tolerated dose (RD-MTD) of DHA-dFdC was 50 mg/kg. DHA-dFdC exhibits a strong efficacy at or below its RD-MTD in mouse models of pancreatic cancer or leukemia. Unfortunately, DHA-dFdC has two main issues, chemical instability and poor solubility in water. In this dissertation, a solid lipid nanoparticle (SLN) formulation of DHA-dFdC was developed to improve its chemical stability and water solubility. The SLN formulation improves the apparent water solubility of DHA-dFdC by 2.6-fold, as compared to a previously developed DHA-dFdC in Tween 80-ethanol-water solution. The SLN formulation as a lyophilized powder also improves the chemical stability of DHA-dFdC. In addition, DHA-dFdC-SLNs showed stronger antitumor activity than DHA-dFdC in Tween-ethanol-water solution in a mouse model when given intravenously. Finally, this dissertation demonstrates in a mouse model that the absolute oral bioavailability of DHA-dFdC in the DHA-dFdC-SLN formulation is 68%. It is concluded that the SLN formulation of the DHA-dFdC (i.e. DHA-dFdC-SLNs) improves the chemical stability of DHA-dFdC and increases its apparent water solubility, and the DHA-dFdC-SLNs can be administered intravenously or orallyItem Academic and social influences of underrepresented adolescents' perceptions of opportunity and plans for the future(2016-08) Kyte, Sarah Blanchard; Riegle-Crumb, Catherine; Callahan, Rebecca M; Crosnoe, Robert; Muller, Chandra; Raley, KellySociologists of education have long stressed the importance of students’ expectations for their subsequent success. Yet, an insufficient amount of previous work has considered how academic and social psychological factors guide when and how students develop their expectations for the future, particularly for the socioeconomically disadvantaged and minority students attending our cities’ schools. By using rich survey and administrative data from a large, urban district serving low income and predominantly Hispanic and African American students, this dissertation identifies how these students develop expectations related to higher education in general as well as science, technology, engineering, and math (STEM) in particular at the start of high school. Chapter 2 examines whether Hispanic girls hold higher college expectations than Hispanic boys because they acquire a superior toolkit of academic resources including achievement, attitudes, and relationships, and/or whether girls are better able to leverage these resources. Further, it considers the potentially gendered role of nativity, language-minority, and socioeconomic status in shaping college expectations among Hispanic students. Chapter 3 analyzes how students’ perceptions of the relevance of science outside of school contribute to gender differences in expectations to major in specific areas of STEM, namely the biological and physical sciences as compared with computer science and engineering. Chapter 4 unpacks the extent to which minority students expecting to major in STEM anticipate that gender- or race-based discrimination may act as a barrier to their goals. Taken together, the findings of these studies underscore the importance of perceptions related to schools, society, and opportunity at the intersection of gender and race/ethnicity for guiding students’ expectations, an important precursor to subsequent behavior and success.Item Efficacy of constraint-induced language therapy for treating acquired apraxia of speech(2011-05) Swinson, Rachel Elizabeth; Marquardt, Thomas P.; Harris, Joyce L.This report investigates the efficacy of using constraint-induced language therapy (CILT) for treating acquired apraxia of speech (AOS). CILT is a treatment method used with individuals with aphasia in which communication is restricted to verbal output in order to isolate the damaged language areas of the brain and reactivate impaired neural connections (Pulvermuller et al., 2001). CILT employs repetitive, massed practiced stimuli and structured shaping of expressive output within the confines of verbal expression (Pulvermuller et al., 2001). Kirmess and Maher (2010) indirectly discovered that two patients with aphasia and apraxia of speech made gains in both language output and articulatory accuracy after receiving intensive CILT, suggesting possible efficacy for the use of CILT with patients with AOS.Item The efficacy of electrical-stimulation for acquired dysphagia : a critical literature review(2012-05) Spivack, Jennifer Naomi; Marquardt, Thomas P.; Granof, DenaElectrical stimulation has been a controversial treatment option for acquired dysphagia since the initial study by Freed, Freed, Chatburn, and Christian (2001). This report investigates the efficacy of electrical stimulation by addressing three issues related to the use of this technique: 1) the movement of the hyolaryngeal complex during stimulation, 2) the population(s) for which electrical stimulation is efficacious, and 3) the necessity of combining electrical stimulation with traditional treatments for the treatment to be effective. Twenty-two studies were evaluated and revealed overall positive findings for the use of electrical stimulation as a treatment technique. To further analyze the strength of these findings, the studies were evaluated for methodological limitations with regards to participant selection, treatment design, and outcome measure selection. This analysis revealed two main methodological limitations: 1) a lack of established treatment protocol which led to differences in how and with what other techniques electrical stimulation was used and 2) an absence of follow-up measures. While these factors do not appear to affect the applicability of the study findings, future research should focus developing a treatment protocol and investigating the long-term benefits of electrical stimulation treatment.Item Minimal contrasts and maximal oppositions : an evidence-based practice brief(2012-05) Crockett, Jeffrey Neil; Byrd, Courtney T.; Bedore, Lisa A.This report presents a comprehensive review of efficacy studies for minimal contrasts therapy and maximal oppositions therapy. The target population was defined as children with phonological disorders who had no co-occurring impairments in hearing, receptive language, speech articulation, or oral-motor structure and function. Thirty three minimal contrasts studies from 1981 to 2008 and six maximal oppositions studies from 1990 to 2008 were identified. No studies from 2009 to 2012 were found. The majority of the studies were either Level III (descriptive studies, 34.2%) or Level IIb (quasi-experimental studies, 57.9%). Twenty three studies reported treatment duration, which ranged from six to 58 hours. Based on reports of treatment success and generalization to new linguistic and communicative contexts, it was found that minimal contrasts therapy has greater support in the literature. Additional studies using a uniform methodology will be needed to establish the validity of maximal oppositions therapy. Recommendations are made for future studies of minimal contrasts and maximal oppositions.Item Modeling lesbian, gay, and bisexual patient disclosures : an exploration of the role of memorable messages, past experiences, perceived visibility, screening behaviors, and efficacy(2015-08) Brown, Laura Elizabeth, Ph. D.; Donovan-Kicken, Erin E.; Dailey, Rene; Vangelisti , Anita; McGlone, Matt; Whittaker , TiffanyLesbian, gay, and bisexual (LGB) people in the United States face unique challenges such as the denial of civil and human rights, discrimination, and societal stigma (HealthyPeople.gov). These challenges facilitate additive minority stress, as evidenced by significantly poorer physical and mental health outcomes for LGBs as compared to heterosexuals. One root of these health disparities is a disclosure-based dilemma in the patient-provider context. Summarized, this dilemma is: "Should I reveal my sexual orientation to my doctor and risk discrimination or stigmatization, or should I conceal my sexual orientation and risk not receiving quality medical care that is tailored to my needs as a patient?" This study investigated competing, predictive models, all of which are grounded in existing research regarding interpersonal health communication and LGB health. The models hypothesized that the following variables predict likelihood of disclosure of sexual orientation: Memorable messages about sexual orientation and receiving care, past disclosure experiences in the patient-provider context, self-perceived visibility of sexual orientation, and patients' pre-screening behaviors of providers. Disclosure efficacy and target efficacy were predicted to mediate these relationships. LGB individuals (N = 209) completed an online questionnaire about receiving health care. Results revealed that disclosure efficacy mediated the predictive relationship between positivity of a past disclosure experience and likelihood of future disclosure. Significance of a past disclosure experience directly, negatively predicted likelihood of future disclosure. Some evidence indicated that self-perceived visibility of sexual minority status positively predicted likelihood of future disclosure. Results failed to support the predictive power of memorable messages and patients' pre-screening behaviors of providers. Theoretical contributions to interpersonal communication models of disclosure are offered, as are practical contributions meant to address patient-provider interactions and, more broadly, the reduction of health disparities for LGB individuals.Item Perceptions of teachers' preparedness and efficacy beliefs for teaching English language learners(2011-08) Tran, Yune Kim; Salinas, Cinthia; Fuller, Ed; Tinajero, Josefina; DeLissovoy, Noah; Valenzuela, AngelaThe changing and growing student population in the U.S. demands well-equipped and trained teachers who have the adequate preparation and pedagogical tools to fully meet their diverse needs. This research study examined the perceptions of teachers’ preparedness and their efficacy beliefs for teaching English Language Learners. A mixed-method was carried out to address four research questions: 1) What perceptions are held by in-service teachers about teaching practices for ELLs? 2) What is the relationship, if any, between teacher knowledge about teaching ELL students and the instructional practices employed by teachers when instructing ELL students? 3) How effective do in-service teachers feel in teaching ELL students? 4) What factors influence teachers’ perceptions of self-efficacy about teaching ELL students? Over 144 teachers participated in the survey questionnaire along with five teachers who participated in focus-groups, interviews, and classroom observations to identify in-depth analysis on their feelings of perceptions and efficacy beliefs. Results from the quantitative study revealed differences in perception and efficacy beliefs for teachers who are bilingual in a second language, teachers who hold a bilingual/ESL certification, and the route in which teachers receive their certification. Qualitative results included the methodologies and cultural competencies that teachers employed in their classroom for English Language Learners. Additionally, participation in professional development activities was found to have an effect in teachers’ instructional decisions for teaching ELLs.Item The relationship between glycine receptor agonist efficacy and allosteric modulation(2014-05) Kirson, Dean; Mihic, S. JohnThe glycine receptor (GlyR) is a ligand-gated ion channel member of the cys-loop receptor superfamily, responsible for inhibitory neurotransmission in the brain and spinal cord. Both glycine and the partial agonist taurine act as endogenous ligands of the GlyR. Taurine-activated GlyR may have a role in the rewarding effects of drugs of abuse, such as ethanol. As a partial agonist, taurine has a decreased efficacy relative to glycine, resulting in a decreased maximum response. We investigated the effects of ethanol, anesthetics, inhalants, and zinc to determine if these allosteric modulators could increase the efficacy of the taurine-activated GlyR. Whole cell recordings of wild type GlyR revealed that each of the allosteric modulators potentiated currents generated by saturating concentrations of taurine but not glycine, implying an increase in efficacy. Zinc is found at GlyR-potentiating concentrations throughout the nervous system, so we examined the combinatorial effects of these allosteric modulators with zinc to mimic in vivo conditions. Whole cell recordings revealed that zinc potentiation of saturating taurine-generated currents decreased further potentiation by another allosteric modulator, indicating no synergistic effects on efficacy. We next investigated the actions of ethanol and isoflurane on the taurine-activated GlyR at the single channel level, finding that both allosteric modulators stabilized the channel open state, increasing the efficacy of the taurine-activated GlyR. We previously identified a mutation in the ligand-binding domain of the GlyR (D97R) that produces spontaneously activating channels, on which taurine has increased efficacy. We identified a residue, R131, as a possible binding partner of D97 in forming an electrostatic interaction that holds the channel in the closed state. We found that disruption of this interaction results in greatly increased taurine efficacy, indicating that efficacy for partial agonists may be determined by agonist ability to break this bond early in the activation process following binding. Thus we find differential mechanisms of allosteric modulation and efficacy determinations for the GlyR when activated by taurine vs. glycine.Item Spironolactone to treat hypertension in end-stage renal disease : analysis of effectiveness and safety(2013-05) Smith, Amber Lanae; Koeller, JimPurpose: Cardiovascular events and complications are the major causes of death in patients with end-stage renal disease (ESRD)¹⁻³. Antihypertensive agents that block the renin-angiotensin-aldosterone system (RAAS) are considered first-line therapy in patients with ESRD as these patients have a propensity for RAAS overactivation⁴⁻⁷. Studies show that aldosterone receptor blockade reduces BP in patients with chronic kidney disease (CKD) and helps prevent negative outcomes from continued renal cellular damage⁸⁻¹⁰. Spironolactone, an aldosterone antagonist, has the potential to provoke hyperkalemia. Consequently, current guidelines do not recommend spironolactone to manage hypertension in ESRD because of this risk⁶⁻⁷. Our primary objectives were to determine the change in BP and serum potassium levels following spironolactone use. Methods: This study was a retrospective, pre-post cohort study in ESRD patients with difficult-to-control BP receiving HD. Patients prescribed spironolactone (25 mg to 50 mg) between January 2009 and January 2013 were identified using an e-prescribing record from three HD clinics in San Antonio, TX. Patients were included if they were prescribed spironolactone as 'add-on' therapy to control BP for at least 8 weeks. Results: Seventy patients were evaluated and the majority of them were overweight, diabetic, Hispanic females with a mean 65 years of age. Mean SBP and DBP decreased from baseline to week 8 [-20.74 mmHg (p < 0.0001) and -9.7 mmHg (p < 0.0426), respectively]. Mean serum potassium levels increased by an average of 0.18 mEq/L (4.5 mEq/L to 4.68 mEq/L, p = 0.09). Data analysis revealed that only 9 of 70 patients had a serum potassium level > 5.5 mEq/L at week 8. There were no adverse cardiac events reported as a result of these potassium concentrations. A two-fold decrease in SBP was seen in patients with a body mass index (BMI) > 25 kg/m² compared to patients with a BMI of ≤ 25 kg/m². At the end of the study, 23 patients (33%) achieved the goal BP for healthy adults of < 140/90 mmHg. Conclusion: These findings demonstrated that using spironolactone use in ESRD patients receiving HD can be effective and safe.Item The complex nature of equitable STEM instruction : emotion, cognition, and constraints(2019-08-19) Welch-Ptak, Jasmine Joy; Callahan, Rebecca M.; Riegle-Crumb, Catherine; Keating, Xiaofen; Sampson, Victor; Treisman, UriEquitable STEM instruction aims to alleviate the perpetual achievement gap by ensuring students have access to multiple opportunities to engage in rich inquiry-based activities and content-specific discourse practices. The three studies in this dissertation explore the complexity inherent to the implementation of such equitable practices in the current high-stakes accountability context. With the first analytic chapter, I seek to draw attention to the negative emotions that emerge during open-ended activity, and the need to identify specific pedagogical practices that can normalize difficulty and persistence as a necessary part of learning. I suggest interested practitioners integrate the straightforward approach I highlight in this chapter into any instructional innovation. However, in my second analytic chapter I present a multi-site case study of the challenges teachers at two distinct school sites report to impede their implementation of curricular innovations. Although the two sites look very different in terms of student and teacher demographics, teachers at both sites report similar challenges to implementation. The third and final, analytic chapter is a quantitative survey analysis I conducted that examines one of the key challenges reported: teacher efficacy. Specifically, my study explores differences in preservice teachers’ teaching efficacy for culturally and linguistically diverse students in STEM contexts based on their pedagogical preparation and personal linguistic background. Findings from the three studies have potential implications for education policy, practice, teacher preparation, and research