ScholarWorks@UMassAmherst

Recent Submissions

  • Research Project
    Afghanistan University Support and Workforce Development Program (USWDP)
    (Center for International Education, UMass Amherst, 2014-06) Evans, David R.
    A PowerPoint presentation introducing the new Afghanistan University Support and Workforce Development Program (USWDP) and the transition process from the previous HEP2 project. It summarizes the achievements of the two earlier HEP projects and the challenges of new USWDP. project.
  • Research Project
    Basics of Academic Research
    (Center for International Education, UMass Amherst, 2013-07) Multiple Authors
    The purpose of this “Basics of Academic Research Module” is to provide all professors both young and old the basic elements of academic research. It is hoped that this module will be a tool to assist them with promotion within their institutions, but also contribute to the Afghan academic community. Finally, this module is also a tool to teach students critical research skills that they will need to carry on scholarly work for future generations. It should be noted that an academic research course generally takes at least 6 weeks to a semester. This is a training outline that provides information on different elements of academic research to be delivered once a week over a six week period so that can complete their homework. For each of the six activities it provides a pre-reading discussion, a reading, a post-reading activity, a in-class practice, and homework.
  • Research Project
    Using Case Sudies as a Teaching Tool
    (Center for International Education, UMass Amherst, 2012-12) Multiple Authors
    The document Introduces the basics of creating and applying case studies as a tool for learning in the classroom as a way to engage students in active learning. it suggests ways to use case studies in large classes. The contents include nine detailed training modules with illustrative case studies
  • Publication
    Convective forces contribute to post‐traumatic degeneration after spinal cord injury
    (Wiley, 2025-01-14) Kwon, Hoi; Streilein, Christopher; Cornelison, Chase
    Spinal cord injury (SCI) initiates a complex cascade of chemical and biophysical phenomena that result in tissue swelling, progressive neural degeneration, and formation of a fluid-filled cavity. Previous studies show fluid pressure above the spinal cord (supraspinal) is elevated for at least 3 days after injury and contributes to a phase of damage called secondary injury. Currently, it is unknown how fluid forces within the spinal cord itself (interstitial) are affected by SCI and if they contribute to secondary injury. We find spinal interstitial pressure increases from −3 mmHg in the naive cord to a peak of 13 mmHg at 3 days post-injury (DPI) but relatively normalizes to 2 mmHg by 7 DPI. A computational fluid dynamics model predicts interstitial flow velocities up to 0.9 μm/s at 3 DPI, returning to near baseline by 7 DPI. By quantifying vascular leakage of Evans Blue dye after a cervical hemi-contusion in rats, we confirm an increase in dye infiltration at 3 DPI compared to 7 DPI, suggestive of higher fluid velocities at the time of peak fluid pressure. In vivo expression of the apoptosis marker caspase-3 is strongly correlated with regions of interstitial flow at 3 DPI, and exogenously enhancing interstitial flow exacerbates tissue damage. In vitro, we show overnight exposure of neuronal cells to low pathological shear stress (0.1 dynes/cm2) significantly reduces cell count and neurite length. Collectively, these results indicate that interstitial fluid flow and shear stress may play a detrimental role in post-traumatic neural degeneration.
  • Publication
    Rapid Detection of Titanium Dioxide in Food Products using X-Ray Fluorescence Spectroscopy
    (2024-09) Sankaranarayanan, Prarthanaa
    Titanium dioxide (TiO2) is a white, odorless, and tasteless powder used as the colorant E171 in candies, pudding, coffee creamers, etc. The potential toxicity of E171 led to its ban as a food additive in the EU starting 2022, when the European Food Safety Authority (EFSA) declared E171 as no longer considered to be safe when as a food additive, as they could not exclude genotoxicity concerns after consumption of titanium dioxide particles. However, the current regulations imposed by the US FDA only restrict the amount of TiO2 used in food, which is set at 1% by weight of the food and it is not required to be explicitly listed on the label. There are large knowledge gaps about the amount of titanium dioxide being used in food products in the US and how much of the population is being exposed to it. This study investigates the use of X-ray Fluorescence (XRF) to fill these gaps by developing a rapid and effective method to detect the presence of E171 in various food products and quantify the concentration by weight. This method will help to obtain exposure and concentration data to enable regulatory bodies to facilitate a reliable risk assessment. Since existing methods for detection such as Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) are expensive, require lengthy sample preparation and utilize dangerous chemicals such as hydrofluoric acid, there is a dire need for a more rapid and cost-effective way to detect and quantify TiO2 in food. A standard curve with standards from 0.005% to 2% for quantifying the mass concentration of TiO2 was established by using a mixture of E171 with either sucrose or starch as a filling material. Sucrose yielded an excellent linear curve with r2 = 0.9962 and showed limit of detection (LOD) of 0.00059% and limit of quantitation (LOQ) of 0.00197%. A total of 40 food samples in the powder matrix were purchased from the market with and without E171 label claim and tested using XRF. Results showed the presence of E171 in 30 samples, with 16 samples having explicit label claim and 14 samples without. The concentrations ranged from 0.003% to 0.486% TiO2 with the highest category being coffee creamers and the lowest TiO2 content in seasonings. The method was validated by running the samples on ICP-MS which yielded similar results. Recovery tests were also run giving percent recovery in the range of 70%-100%. This method was also adapted to include other matrices that food products exist in, such as solid, semi-solid and liquid. Several sample preparation methods were tested for semi-solid samples. An emulsion was developed to create a standard curve with concentrations from 0.005% to 2%, which showed great linearity with r2 = 0.9959 and LOD = 0.000054% and LOQ = 0.00018%. This showed optimal results and was used for analysis of all products in this matrix. The highest concentration was found in a Queso Blanco with 0.739% TiO2. Other matrices such as solid included hard candy products, which could be quantified using the previous standard curve. This proves the ability of XRF to perform elemental analysis in a wide range of products. However, some limitations of the method include samples such as jellies and certain confectionery items which require a more specific and extensive preparation method to be used with XRF. Recovery tests were used for validation and percent recovery values from 80%-100% show that this can be a great semi-quantitative method, which is capable of screening a large number of food products for E171 in a rapid and efficient manner. An exposure assessment was also performed by considering the population consumption data from national surveys and amount of titanium dioxide present in each product. Estimated daily intake was obtained as 0.795 mg/kg bw. Overall, this study has proposed a valuable tool to rapidly and effectively detect and quantify or semi-quantify TiO2 in food and filled the existing gaps about population exposure to this additive.

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