«Strengthening the Nation through Diversity, Innovation & Leadership in STEM San Antonio,Texas · October 3-6, 2013 Get Connected! Connect with the ...»
Research in mathematics education has shifted towards a sociopolitical perspective on equity, classified as critical mathematics education. As such, researchers are developing ways of defining and measuring student identity in relation to mathematics. Specifically, methods of defining students’ identity are influenced by researchers’ experiences within the field, either as past teachers, researchers observing the field, or teacher educators. With research calling for more student learning positioning in the classroom, professional development programs are transforming the resources to better support students. This poster presents a meta-analysis of literature in critical mathematics that explores how student agency and identity can be defined and the role that mathematics plays in that definition.
Results from 32 articles/chapters reviewed show that how researchers position themselves within the field influences the methods and definitions of mathematics and student identity they develop. As of now, the majority of research studies talk about students gaining resiliency to confront stereotypes that they face and very little about how math Graduate
mathematical identities should not just consider how math contributes to students’ identities, but should also show how students can contribute to the identity of mathematics. By moving research beyond the notion of students being math doers and seeing mathematics as a way of shaping our world, students can see themselves as contributors in creating a new world and a more humanistic version of mathematics.
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SYSTEMIC FUNCTIONAL LINGUISTICS AS A TOOL FOR EXAMINING NOS/OTR@S EXPERTISE IN A
SECONDARY MATHEMATICS PRESERVICE SEMINARJuan M. Gerardo, Rochelle Gutierrez.
University of Illinois at Urbana-Champaign, Champaign, IL.
Mathematics education researchers use discourse analysis to analyze small-group and whole-group discussions.
Systemic functional linguistics (SFL), more specifically, the system of negotiation, is one methodological approach that researchers are beginning to use to examine authority in interactions. To date, most SFL research focuses on K to 12 classrooms where teachers are older than students. In contrast, we examined the extent to which preservice secondary mathematics teachers (PSMTs) were positioned as experts during two lessons in a teacher education seminar, one mathematical, and the other pedagogical. Our theoretical framework assumes the PSMTs will acknowledge teaching is a political act and strive to develop solidarity and interdependent (nos/otr@s) relationships with marginalized students. That is, they will aim to position their students as experts. We wanted to test if the research team, indeed, was modeling this kind of behavior of positioning students as experts during interactions with the PSMTs. Using SFL, we coded for moves that positioned PSMTs as experts and when they positioned themselves as experts. The analysis shows that PSMTs were not positioned as experts in a mathematics problem led by an accomplished teacher (and member of the research team) as often as when the PSMTs were discussing a pedagogical lesson with the same teacher. By focusing on the kinds of questions that were asked, SFL helped elucidate when authority was located within a single person and when it was distributed among several people.
Implications for future research are discussed.
AEROSPACE, AERONAUTICAL, ASTRONAUTICAL ENGINEERINGBallroom C - 101
THE EFFECTS OF VARIOUS COMBUSTION TECHNIQUES IN A SUBSONIC TURBINE-LESS ENGINE THROUGH
COMPUTATIONAL INVESTIGATION AND EXPERIMENTAL VALIDATIONHakob Karaoglanian, Joseph David Wells, Chivey Wu.
California State University, Los Angeles, Los Angeles, CA.
A new high-powered, green, clean, turbine-less engine has been developed at California State University, Los Angeles. While successfully tested and run without a mixing chamber, the present study will investigate computationally and experimentally different mixing and combustion techniques to see which will provide the ultimate amount of thrust through a cylindrical shaped mixing chamber. Due to its chemistry and clean byproducts when burned, hydrogen will be used as the fuel source initially in the present study. Hydrogen is very light and abundant on Earth and will be the stepping stone to segue ourselves away from harmful energy sources into an age of clean, renewable energy.
BIOENGINEERING/BIOMEDICAL ENGINEERINGBallroom C - 131
ENHANCED DELIVERY AND IMAGING OF NEUROTHERAPEUTICS VIA US, MRI, SPECTMichael Valdez1, Ted Trouard1, Pier Ingram1, Paul Helquist2, Robert Erickson1, Russell Witte1, Terry Matsunaga1, Lars Furenlid1, Zhonglin Liu1.
University of Arizona, Tucson, AZ, 2University of Notre Dame, Notre Dame, IN.
1 Niemann-Pick type C (NPC) disease is an incurable and fatal childhood disease. The disease is characterized by a buildup of cholesterol in the brain resulting in cognitive decline and eventually death. Cyclodextrin (CD) has been shown to bind cholesterol and transport it out of cells, but CD does not cross the blood-brain barrier. This represents a major obstacle for using CD treatment in children. Transient and nondestructive opening of the blood-brain barrier (BBB) has been demonstrated in mice by using ultrasound (US) in conjunction with microbubble contrast agents.
We are investigating the use of this technique to treat NPC disease with CD. Mouse models of NPC will be used in conjunction with US and CD treatment. MRI is currently being used to assess the opening of the BBB by coinjecting gadolinium-DTPA (Gd-DTPA) with the microbubbles and carrying out T1-weighted MRI.
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PLATELET STORAGE: A CHILLING STORYKristin Reddoch1, Prajeeda Nair1, Robbie Montgomery2, Heather Pidcoke2, Chriselda Fedyk2, Anand Ramasubramanian1, Andre Cap2.
University of Texas at San Antonio, San Antonio, TX, 2United States Army Institute of Surgical Research, San 1 Antonio, TX.
Platelets are transfused to prevent bleeding and induce hemostasis and can be critical in saving lives following trauma. Currently, platelets are stored at room temperature (RT) for up to 5 days. This short shelf life severely compromises platelet inventories owing to a high risk of bacterial contamination. Cold storage (4 °C) of platelets can lower this risk, but the actual practice has been abandoned since cold activates platelets and causes rapid clearance from circulation. In cases of severe trauma, 4 °C platelet storage may help achieve faster control of bleeding and improve patient outcomes. In this work, we evaluated the hemostatic potential of platelets stored at 4 °C and RT under standard blood banking conditions for up to 5 days using clinically relevant assays. Single-donor apheresis platelets were collected from 5 donors and stored at RT or at 4 °C with agitation. Measurements were made on days 1, 3, and 5 to assess platelet quality, metabolism, aggregation, clot strength, adhesion, activation, microparticle release, and soluble factor release. Cold storage of platelets proved superior in terms of function, preservation of platelet metabolism, and minimization of the amount of soluble marker release compared to RT. While there is currently no single assay in the market that accurately predicts in vivo performance, the data obtained from this study suggests a need to further explore the use of cold temperatures, particularly for treatment of severe hemorrhage, in times where quick and efficient hemostasis is the determining factor between life and death. (This work was partially funded by NIGMS MBRS-RISE GM060655.) Ballroom C - 107
MODELIZATION OF PHOTOACOUSTIC SIGNALS FROM MAGNETICALLY ORIENTED GOLD NANORODSGilbert Bustamante, Jing Yong Ye.
University of Texas at San Antonio, San Antonio, TX.
Gold nanorods exhibit a high optical absorption that can be tuned based on the aspect ratio. When the gold Graduate Poster nanorods are excited with a nanosecond laser pulse, they can produce ultrasonic waves through thermoelastic effects. Thus, gold nanorods may be used as contrast agents for photoacoustic imaging. The strength of the signal is dependent on several factors, including the angle between the polarization of the excitation light and the rod orientation. Having the ability to control the orientation of the gold nanorod allows one to optimize the photoacoustic signal when the polarization of the laser is parallel to the rod. We propose to build a computational model of a gold nanorod conjugated with an iron nanoparticle on one end of the rod and use an external magnetic field to control the orientation of the nanoparticle conjugates. Two dimensional models will be used to calculate the minimal forces needed to orient the rod and the intensity of the photoacoustic signals from the excited gold nanorod. We plan to implement the experiment in the future using the information from the simulations.
(Partially funded by NIGMS MBRS-RISE GM060655.)
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ORGANIC AMPHIPHILIC NANOSTRUCTURES FOR PHOTOTHERMAL ABLATION OF TUMORSTravis Cantu, Jennifer Irvin, Tania Betancourt.
Texas State University, San Marcos, TX.
Currently, chemotherapy is the most widely used technique to treat cancer. Although this method is effective at treating certain stages and types of cancer, there is a need for more direct treatment. Recently, one technique that has gained interest due to high selectivity is photothermal therapy (PTT). The PTT approach uses photoabsorbing agents to burn cancer cells by generating heat from externally applied optical energy. The vast majority of research focused on PTT is on the inorganic nanomaterials that absorb light in the near-infrared (NIR) region. We are currently developing an organic-based PTT nanomaterial. The polymer being studied is bis-3,4-ethylenedioxythiophene (EDOT)-benzene (BEDOT-B) and the surface will be modified with polyethylene glycol (PEG). This is an electroactive polymer-based material with an absorbance in the NIR region. BEDOT-B will be synthesized from coupling 1,4-dibromo-2,5-dihexyloxy-benzene and EDOT. Once the monomer is formed, BEDOT-B will be synthesized using electrochemistry. The 1,4-dibromo-2,5-dihexyloxy-benzene has been synthesized and characterized using H1NMR (CDCl3, ppm): 7.09 (s), 3.95 (t), 1.80 (m), 1.47 (t). Further characterization will be done using C13NMR, and FTIR. Nanoparticles will be characterized by dynamic light scattering, zeta-potential analysis, fluorescence, absorption spectroscopy, and by transmission and scanning electron microscopy (TEM and SEM, respectively). The photothermal capabilities of the materials will be studied by irradiating an aqueous suspension with a NIR light source.
In vitro studies will also be conducted to determine the biocompatibility, specificity, and therapeutic efficacy of these photoablation agents.
Ballroom C - 111
A MULTIOBJECTIVE OPTIMIZATION FRAMEWORK FOR THE CONTROL OF SIZE AND SHAPE DISTRIBUTIONS
OF CRYSTALLIZATION SYSTEMSDavid Acevedo. Zoltan Nagy.
Purdue University, West Lafayette, IN.
Optimization studies of batch crystallizers to determine temperature trajectories for controlling properties of the crystal size distribution (CSD) have been commonly performed by using one-dimensional population balance models (PBM). However, the properties of the crystalline products are significantly influenced by both the size and shape distribution of the particles. Crystals experience changes both in size and shape during the process. Size and shape are strongly coupled properties. The purpose of the current work is to provide a systematic investigation of the classes of crystallization systems for which optimal temperature trajectories can be determined that simultaneously control properties of the CSD and shape. A generic, multidimensional PBM is implemented for unseeded crystallization processes. The model is used in optimization studies considering different kinetics such as fast/slow growing systems, and growth versus nucleation dominated processes, and various objective functions. Multiple performance objectives lead to significantly different optimal operating conditions. A multi-objective approach has been implemented that gives rise to a set of Pareto-optimal solutions, which is determined via a sequential quadratic programming (SQP) framework. The equivalent spherical diameter and aspect ratio were proposed as size and shape related performance objectives. The effect of shape related objectives on size objectives is shown through the analysis of the Pareto front for size and size-shape controlled cases. The proposed study provides a systematic understanding of the types of crystallization systems for which size and shape can be manipulated and the level at which shape distribution can be controlled by manipulating the supersaturation only.
CIVIL ENGINEERINGBallroom C - 120
SUSTAINABLE DEVELOPMENT AND TRANSPORTATION DECISION MAKING: INCORPORATING PUBLIC
PREFERENCES USING VISUALIZATIONDavis Chacón Hurtado, Alberto Figueroa Medina, Christopher Papadopoulos, Marcel Castro Sitiriche.
University of Puerto Rico at Mayagüez, Mayagüez, PR.