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- Creators: Harrington Bioengineering Program
This thesis presents a preliminary determination and design of a control algorithm for an assistive ankle device developed by the ASU RISE Laboratory. The assistive ankle device functions by compressing a spring upon heel strike during gait, remaining compressed during mid-stance and then releasing upon initiation of heel-off. The relationship between surface electromyography and ground reactions forces were used for identification of user-initiated heel-off. The muscle activation of the tibialis anterior combined with the ground reaction forces of the heel pressure sensor generated potential features that will be utilized in the revised control algorithm for the assistive ankle device. Work on this project must proceed in order to test and validate the revised control algorithm to determine its accuracy and precision.
Polymeric nanoparticles (NP) consisting of Poly Lactic-co-lactic acid - methyl polyethylene glycol (PLLA-mPEG) or Poly Lactic-co-Glycolic Acid (PLGA) are an emerging field of study for therapeutic and diagnostic applications. NPs have a variety of tunable physical characteristics like size, morphology, and surface topography. They can be loaded with therapeutic and/or diagnostic agents, either on the surface or within the core. NP size is an important characteristic as it directly impacts clearance and where the particles can travel and bind in the body. To that end, the typical target size for NPs is 30-200 nm for the majority of applications. Fabricating NPs using the typical techniques such as drop emulsion, microfluidics, or traditional nanoprecipitation can be expensive and may not yield the appropriate particle size. Therefore, a need has emerged for low-cost fabrication methods that allow customization of NP physical characteristics with high reproducibility. In this study we manufactured a low-cost (<$210), open-source syringe pump that can be used in nanoprecipitation. A design of experiments was utilized to find the relationship between the independent variables: polymer concentration (mg/mL), agitation rate of aqueous solution (rpm), and injection rate of the polymer solution (mL/min) and the dependent variables: size (nm), zeta potential, and polydispersity index (PDI). The quarter factorial design consisted of 4 experiments, each of which was manufactured in batches of three. Each sample of each batch was measured three times via dynamic light scattering. The particles were made with PLLA-mPEG dissolved in a 50% dichloromethane and 50% acetone solution. The polymer solution was dispensed into the aqueous solution containing 0.3% polyvinyl alcohol (PVA). Data suggests that none of the factors had a statistically significant effect on NP size. However, all interactions and relationships showed that there was a negative correlation between the above defined input parameters and the NP size. The NP sizes ranged from 276.144 ± 14.710 nm at the largest to 185.611 ± 15.634 nm at the smallest. In conclusion, the low-cost syringe pump nanoprecipitation method can achieve small sizes like the ones reported with drop emulsion or microfluidics. While there are trends suggesting predictable tuning of physical characteristics, significant control over the customization has not yet been achieved.
This study seeks to answer the research questions: What are the major risk factors associated with the lack of prenatal and neonatal healthcare in developing countries? What are potential routes of intervention (ROI) to help these countries? The goal is to analyze the risk factors and determine if there are any ROIs available to minimize potential incidents or accidents associated with complications of preterm birth.
A few potential risk factors include: poverty, a mother’s lack of education, a lack of professional visitation during pregnancy, having a short cervix, and routine use of Ultrasound. This research paper has identified that keeping ultrasound diagnostics to a minimum, seeking professional help during pregnancy, incorporating corticosteroids for preterm births, implementing Kangaroo Mother Care, and Cervical Cerclage are interventions that can reduce preterm births and the associated complications that come with it. We believe that further research, regarding compliance of each of these interventions, would show reduction of preterm births and low birth weight in developing countries.
development on a global scale. Originally, development within a country was solely judged by the degree of economic growth by way of Gross National Product (GNP) and per capita income. Holistically, GNP measures the total extent of economic activity of a country’s people within a given time period. (Rutherford, 2012). Critics found several issues with this one-dimensional approach of measuring human development. What failed to be recognized was the distribution of income among the country’s citizens. Higher incomes often favor men within the majority when compared to women and people of minority groups (Feiner & Roberts, 1990). GNP also failed to recognize the social limitations under a government. In other words, are there limitations as to what goods can be bought and who can buy them?