The colonias along the Texas-Mexico border are one of the most rapidly growing areas in Texas. Because of the relatively low income of the residents and an inadequate availability of transportation services, the need for basic social activities for the colonias cannot be properly met. The objectives of this study are to have a better comprehension of the status quo of these communities by examining the potential demand for an improved transportation service and evaluate the capacity and optimum service time interval of a new demand responsive transit "feeder" service within one representative colonia, El Cenizo. A comprehensive analysis of the results of a survey conducted through a questionnaire is presented to explain the existing travel patterns and potential demand for a feeder service. The results of this thesis and work from the subsequent simulation analysis showed that a single shuttle would be able to comfortably serve 150 passengers/day. It further showed that the optimal cycle length between consecutive departures from the terminal should be between 11-13 minutes for best service quality. This exploratory study should serve as a first step towards improving transportation services within these growing underprivileged communities especially those with demographics and geography similar to the target area of El Cenizo.

This qualitative study examined urban middle school teachers' participation in a teacher study group (TSG) focused on culturally responsive teaching (CRT) content. Specifically, the researcher investigated the professional development experiences of five urban middle school teachers participating in a TSG on CRT and examined how these urban middle school teachers described their learning experiences of the CRT content. A purposeful sample of five teachers was used. Data collection was done with open-ended surveys, semi-structured interviews and field notes during the interviews and TSG sessions. The data were transcribed and analyzed using constant comparison. Data were continuously shuffled, sorted and re-organized as part of the constant comparative method. Through this method, key themes about TSGs and teachers' learning experiences emerged and were reported. The data analysis for research question one produced three overarching themes: changes in perception of staff development, building relationships and impact on instruction. Each theme had descriptors that further explain more specific aspects of the data results. The second research question was designed so the researcher could report descriptions of each participant's learning experiences of CRT content from the TSG experience. Two major themes emerged for research question two: personal and professional development. The discussion offers considerable support for the findings of existing research on TSGs and the positive attitude towards this design of professional development. The importance of building relationships in TSGs and the impact this TSG had on instruction are contributed to the literature. In this study the findings are reported in the voices of the participants, which is lacking in the current literature. Also, two major themes of the participants' learning of CRT are presented, personal and professional responsibilities, which are new to the existing literature. In conclusion, this research produced two important results for the educational realm: 1) the tremendous need for schools and school districts to offer our current practitioners better and more meaningful staff development, 2) Trained and certified teachers have little to no understanding of the tenets of culturally responsive teaching methods. CRT practices that are proving meaningful, validating and effective need to be further studied and reported.

Nanoparticles (such as, carbon nanotubes, carbon black, clay etc.) have one or more dimensions of the order of 100 nm or less. Owing to very high van der Waals force of attraction, these nanoparticles exist in a highly aggregated state. It is often required to break these aggregates to truly experience the “nanosize” effect for any required end use. There are several strategies proposed for dispersing/exfoliating nanoparticles but limited progress has been made towards controlling their dispersion state. The ability to tailor nanoparticle dispersion state in liquid and solid media can ultimately provide a powerful method for tailoring the properties of solution processed nanoparticle-filled polymer composites. This dissertation reports the use of a variety of stimuli-responsive polymers to control the dispersion state of single-walled carbon nanotubes. Stimuli-responsive polymers exhibit conformational transitions as a function of applied stimulus (like pH, temp, chemical etc.). These variations in conformations of the polymer can be used tailor nanotube dispersion state in water and solid composites.The use of pH and temperature responsive polymers to stabilize/disperse single walled carbon nanotubes (SWNTs) in water is presented. Non-covalent functionalization of SWNTs using pH and temperature responsive polymer show tailored dispersion state as a function of pH and temperature, respectively. Carbon nanotube microstructure in these aqueous suspensions was characterized using several techniques (cryo-TEM, viscosity measurements, uv-vis spectroscopy, zeta potential measurements and settling behavior). Furthermore, nanotube dispersion state in aqueous suspensions is preserved to a large extent in the composites formed by drying these suspensions as evidenced by SEM images and electrical conductivity measurements. Based on the results obtained a mechanism is proposed to explain the tailored dispersion of SWNTs as a functions of applied external stimulus (i.e., pH, temperature). Such stimuli-controlled dispersion of carbon nanotubes could have a variety of applications in nanoelectronics, sensing, and drug and gene delivery systems. Furthermore, this dissertation also contains a published study focused on controlling the dispersion state of carbon black (CB) in epoxy composites using clay.

The purpose of this study was to examine the relationship between urban teachers’ perceptions and their implementation of culturally responsive materials into the classroom. Specifically, this study examined the influences of age, years of teaching experience, level of education, professional development, and prior knowledge with culturally diverse populations on perceptions of implementing culturally responsive materials into urban elementary classrooms. Based on the results of this research, the variables of age, teaching experience, and professional development were found to affect how teachers value culturally responsive materials. This suggests that variables can have important ramifications for educators and administrators in urban and culturally diverse schools.

Poly(N-isopropylacrylamide) (PNIPAM), a temperature responsive polymer, undergoes a phase change at a lower critical solution temperature (LCST) in aqueous solutions. For PNIPAM this temperature is 32 °C in water. Below the LCST, the polymer is readily solvated by water. As the temperature of the solution increases, the polymer undergoes a phase transition so that above the LCST it is no longer water soluble. The LCST of PNIPAM may be changed by the addition of salt solutions from the Hofmeister series which will follow the Hofmeister effect for salting-in and salting-out the polymer. Temperature responsive polymers may be grafted to a surface in a variety of methods to create responsive thin films that exhibit a change in wettability. The surface wettability is directly related to the polymers ability to be solvated in its coil conformation. When PNIPAM is grafted to a surface, the surface becomes alternatively hydrophobic and hydrophilic in response to both temperature and the anions in the Hofmeister series which take the surface either above or below the LCST of PNIPAM. The synthesis of responsive nanocomposite grafts was successfully applied to glass slides and three-dimensional surfaces, porous glass frits which were capable of controlling the passive flow rate. The nanocomposite graft was assembled in a covalent layer-by-layer approach to create more chemically robust surfaces, and also to incorporate nanoparticles into the graft for increased surface roughness and therefore improve wettability response. Because of a much greater inherent roughness to a glass frit, characterization of the polymers and nanoparticles was performed before they were covalently bound to the surface. The final product, a functionalized frit with a PNIPAM/SiO2 nanocomposite graft, was analyzed by observing changes in the passive permeation rate of the frit between water and salt solutions. These changes in flow were indicative of the surface bound PNIPAM changing between its hydrophilic and hydrophobic conformation in response to water and concentrations of kosmotropic salts such as sodium sulfate and sodium citrate. In addition to the solute response, the frit was also determined to be responsive to temperature and concentration. Water exhibited a passive flow rate 1000 times faster than a kosmotropic salt but had a similar flow rate to that a chaotropic salt. By measuring the flow rate of 0.5 M Na2SO4 at ~7 °C in a cold room and at room temperature it was observed that sodium sulfate in the cold room passed through the frit at a rate 100 times faster than at room temperature. Because of the hysteresis of PNIPAM documented in literature, washing procedures were kept consistent between experiments to achieve more reproducible results. It was concluded that the frits were temperature responsive and had relative standard deviations below 25 percent for flow rates on a single frit. However, standard deviations of flow rates between frits were higher. This was likely due to a combination of factors, such as the frits’ pore size range of 10 μm resulting in the possibility of varied degrees of functionalization of each frit.

Traffic congestion has become a menace to civilized society. It degrades air quality, jeopardizes safety and causes delay. Traffic congestion can be alleviated by providing an effective traffic control signal system. Closed-loop traffic control systems are an example of such a system. Closed-loop traffic control systems can be operated primarily in either of two modes: Time of Day Mode (TOD) or Traffic Responsive Plan Selection Mode (TRPS). TRPS mode, if properly configured, can easily handle time independent variation in traffic volumes. It can also reduce the effect of timing plan aging. Despite these advantages, TRPS mode is not used as frequently as TOD mode. The reason being a lack of methodologies and formal guidelines for predicting the factors and thresholds associated with TRPS mode. In this research, a new methodology is developed for determining the thresholds and factors associated with the TRPS mode. This methodology, when tested on a closed-loop system in Odem, Texas, produced a classification accuracy of 94%. The classification accuracy can be increased to 98% with a proposed TRPS architecture.

Polymer carriers composed of poly(methacrylic acid – grafted – ethylene glycol) (P(MAA-g-EG)) hydrogels modified with poly(butyl acrylate) (PBA) to form IPNs or photopolymerized in the presence of poly(methyl methacrylate) (PMMA) nanoparticles were investigated for their use in the oral delivery of therapeutic agents for cancer treatment. The P(MAA-g-EG) hydrogel provided pH-responsive and hydrophilic properties while PBA or PMMA polymers provided hydrophobic properties. An inulin- doxorubicin conjugate was also synthesized to provide local, direct targeting for the treatment of colon cancer. The pH-responsive behavior of these polymer systems was investigated using equilibrium and dynamic swelling experiments. In gastric conditions (low pH) all materials were in a collapsed state and in intestinal conditions (neutral pH) these material were swollen. The equilibrium swelling ratios decreased with increasing hydrophobic content for both IPNs and compositions of P(MAA-g-EG) containing nanoparticles. The loading efficiencies of doxorubicin, a chemotherapeutic drug, were as high as 56% for IPNs and the IPN structure and hydrophobicity influenced the loading efficiency values. The loading efficiency of doxorubicin using P(MAA-g-EG) containing nanoparticles was as high as 64% and increased with increasing weight percent of PMMA nanoparticles in the P(MAA-g-EG) hydrogel. In gastric conditions (low pH), IPNs released a majority of the encapsulated doxorubicin (up to 70%) as compared to the P(MAA-g-EG) containing nanoparticles (up to 27%). P(MAA-g-EG) containing nanoparticles was used to load and release the inulin-doxorubicin conjugate. Loading efficiency was 54% and release profiles behaved similarly as doxorubicin. Both polymer systems were biocompatible with Caco-2, HT29-MTX, and SW620 cell models over concentration ranging from 1 mg/mL to 5 mg/mL and exposure times lasting from 2 hr to 24 hr. The 75/25 IPN exhibited the highest degree of mucoadhesion and the P(MAA-g-EG)-5.0NP the lowest. Using the same cell lines and cytotoxicity assays, the inulin-doxorubicin conjugate was determined to be more toxic than free doxorubicin at equal doxorubicin concentrations. Doxorobuicin and inulin-doxorubicin conjugate were tested for transport across Caco-2/HT29-MTX cell monolayers with and without the presence of unmodified P(MAA-g-EG) or P(MAA-g-EG)-5.0NP microparticles. The presence of the microparticles did not increase transport across the cell monolayer which is advantageous for local, direct delivery to the colon. / text

Changing student demographics in the state of Texas as well as across the nation make it imperative for educators in K-12 public school settings to develop instructional strategies to meet the needs of increasingly diverse students in multicultural classrooms. To develop greater understandings of this complex issue, culturally responsive teaching was considered through the lens of the instructional coaching professional development model. For purposes of this research study, the culturally responsive/relevant theoretical frameworks of Geneva Gay (2000, 2001, 2004), Ana Maria Villegas & Tamara Lucas (2002), and Gloria Ladson-Billings (1994, 1995) were foundational. Instructional coaching is a job-embedded professional development model for teachers which is gaining increasing attention in K-12 educational settings (Bloom, Castagna, Moir, & Warren, 2005; Kise, 2006; Knight, 2007; Lindsey, Martinez, Lindsey, 2007; Showers, 1984; West & Staub, 2003). Proponents of instructional coaching suggest that coaching is a way to support the reflective practice of educators through a coaching cycle of planning, observation, and reflection. Lindsey, Martinez & Lindsey (2007) further propose a culturally proficient coaching model focused on teachers being responsive to diverse populations of students, and they assert that “coaching and cultural proficiency are integrated sets of tools for guiding individuals and groups to meet cross-cultural issues as opportunities and assets rather than as challenges and deficits” (p. 4). To implement culturally responsive teaching in multicultural classrooms, teachers must develop many skills including the ability to analyze the curriculum-in-use and the ability to implement instructional practices that are efficacious in diverse cultural settings. To support this work, it is further essential that teachers examine their own beliefs and values regarding cultural diversity to enhance their ability to meet the needs of increasingly diverse students. There is strong evidence (Payne & Allen, 2006; Neufeld & Roper, 2003) that instructional coaching contributes to improved teaching and student learning, however, it should be noted that instructional coaching must also be accompanied by rigorous curriculum, on-going formative assessment and feedback for students, strategic planning, and strong local, state and national leadership if educators are to eliminate existing gaps in opportunities to learn between White students and students of color. / text

Teacher decision-making is referred to as the fundamental responsibility of teachers. All teachers are asked to make decisions on a daily basis in their classrooms. For decades researchers have collected data on teacher decision-making in hopes to understand how teachers make decisions and why. Interestingly, most researchers collect data on teacher decision-making only in public school classrooms. The purpose of this study was to collect teacher decision-making data in a nearly unexplored classroom environment, the lower elementary Montessori classroom. The objective of this study was to examine what characteristics operated in the decision-making of two lower elementary Montessori guides. The hypothesis was lower elementary Montessori guides may have more opportunities to understand and approach care and culturally responsive teaching given the Montessori environment seeks to develop the whole child. In order to explore lower elementary Montessori guide decision-making I chose to perform a qualitative case study design. First, I gathered information about the school. Second, I collected data on the two lower elementary Montessori guides in this study. Once data was collected I reviewed the data for emerging themes. Then, I asked the question how was care and cultural responsiveness understood and approached in the decision-making of these two lower elementary Montessori guides.The findings of this study revealed three (3) main influences on the decision-making of lower elementary Montessori guides at River Montessori: (1) Association Montessori Internationale Training (AMI); (2) school ideology; and (3) guide improvisation based on student observation. Care and cultural responsiveness was understood and approached by both lower elementary Montessori guides in this study. However, the enactments of cultural responsiveness fell short of normative understandings of culturally responsive teaching (Gay, 2000; 2002). / text

<p>Cancer is currently the second leading cause of death in the United States. Although many treatment options exist, some of the most common, including radiotherapy and chemotherapy, are restricted by dose-limiting toxicities. In addition, the largest hurdle for translating novel biological therapies such as siRNA into the clinic is lack of an efficient delivery mechanism to get the therapeutic into malignant cells. This work aims to improve this situation by engineering a minimally invasive controlled release system that specifically delivers therapeutics to the site of malignant tissue. This platform consists of two novel material components: a thermally responsive poly[N-isopropylacrylamide-co-acrylamide] (NIPAAm-co-AAm) hydrogel and gold-silica nanoshells. Therapeutic molecules are encapsulated within a poly(NIPAAm-co-AAm) hydrogel carrier, leading to increased serum stability, circulation time, and decreased exposure to off-site tissues. Additionally, gold-silica nanoshells embedded within this hydrogel will be used to optically trigger therapeutic release from the carrier. This hydrogel-nanoshell composite material was designed to be swollen under physiologic conditions (37 oC), and expel large amounts of water and absorbed molecules at higher temperatures (40-45 oC). This phase transition can be optically triggered by embedded gold-silica nanoshells, which rapidly transfer near-infrared (NIR) light energy into heat due to the surface plasmon resonance phenomena. NIR light can deeply penetrate biological tissue with little attenuation or damage to tissue, and upon exposure to such light a rapid temperature increase, hydrogel collapse, and drug expulsion will occur. Ultimately, these drug-loaded hydrogel-nanoshell composite particles would be injected intravenously, passively accumulate in tumor tissue due to the enhanced permeability and retention (EPR) effect, and then can be externally triggered to release their therapeutic payload by exposure to an external NIR laser. This dissertation describes the synthesis, characterization, and validation of such a controlled therapeutic delivery platform.</p><p>Initial validation of poly(NIPAAm-co-AAm)-gold nanoshell composites to act as a material in site-specific cancer therapeutic delivery was accomplished using bulk hydrogel-nanoparticle composite disks. The composite material underwent a phase transition from a hydrated to a collapsed state following exposure to NIR light, indicating the ability of the NIR absorption by the nanoshells to sufficiently drive this transition. The composite material was loaded with either doxorubicin or a DNA duplex (a model nucleic acid therapeutic), two cancer therapeutics with differing physical and chemical properties. Release of both therapeutics was dramatically enhanced by NIR light exposure, causing 2-5 fold increase in drug release. Drug delivery profiles were influenced by both the molecular size of the drug as well as its chemical properties. </p><p>Towards translation of this material into in vivo applications, the hydrogel-nanoshell composite material was synthesized as injectable-sized particles. Such particles retained the same thermal properties as the bulk material, collapsing in size from ~330 nm to ~270 nm upon NIR exposure. Furthermore, these particles were loaded with the chemotherapeutic doxorubicin and NIR exposure triggered a burst release of the drug payload over only 3 min. In vitro, this platform provided increased delivery of doxorubicin to colon carcinoma cells compared to free-drug controls, indicating the irradiated nanoshells may increase cell membrane permeability and increase cellular uptake of the drug. This phenomena was further explored to enhance cellular uptake of siRNA, a large anionic therapeutic which cannot diffuse into cells easily. </p><p>This work advances the development of an injectable, optically-triggered delivery platform. With continued optimization and in vivo validation, this approach may offer an novel treatment option for cancer management.</p> / Dissertation