Mimicking Blood Rheology for More Accurate Modeling in Benchtop Research

To confirm computer simulations and Computational Fluid Dynamics (CFD) analysis, benchtop experiments are needed with a fluid that mimics blood and its viscoelastic properties. Blood is challenging to use as a working fluid in a laboratory setting because of health and safety concerns. Therefore, a blood analogue is necessary to perform benchtop experiments. Viscosity is an important property of fluids for modeling and experiments. Blood is a shear thinning fluid, so it has a decreasing viscosity with higher shear rates. This project seeks to create a blood mimicking fluid for benchtop laboratory use. Numerous fluids with different combinations of water, glycerin, and xanthan gum were created to mimic the shear thinning property of blood at different hematocrit levels. Since the amount of xanthan gum is very small, an analytical balance was used. To mix the solution, an immersion blender and a heat circulator were used. The data were obtained from 10-90 torque percent, which is the range over which the rheometer is accurate, so the exact ranges of shear rate tested depended on the test fluid. The created solutions were compared to blood at the equivalent hematocrit and previously performed tests.The three different equivalent hematocrits all produced results similar to viscosities of blood. The results were similarly representative of blood at different equivalent viscosities for the 0.0075% xanthan gum and the 0.075% xanthan gum by weight. The solutions were able to mimic the shear thinning behavior of blood at different equivalent hematocrits. The fluids with 0.075% xanthan gum and 50% water and 50% glycerin is a better representative than the fluids with 0.075% xanthan gum and 60% water and 40% glycerin

Mimicking Blood Rheology for More Accurate Modeling in Benchtop Research

Because blood is challenging to use as a working fluid in a laboratory setting due to health and safety concerns, a blood analogue would be useful to perform benchtop experiments. Viscosity is an important fluid property for modeling and experiments, especially because blood is a shear thinning fluid; therefore, it has a decreasing viscosity with higher shear rates. This project seeks to create a blood-mimicking fluid for benchtop laboratory use. Numerous fluids with different combinations of water, glycerin, salt, and xanthan gum (XG) were created to mimic blood viscosity at different hematocrit levels. Four additional solutions were also created from the previously mentioned solutions by adding 0.5% by mass salt. The solutions were compared with blood at the equivalent hematocrit (EH) and with previous tests. Three different EHs were tested and all produced results similar to blood viscosities. The solutions were also able to mimic the shear thinning behavior of blood at different EHs. The fluids with 0.075% XG, 50% water, and 50% glycerin were better representative of blood than the fluids with 0.075% XG, 60% water and 40% glycerin. However, no difference in viscosity was found between the fluids with and without salt. These results show that the proposed mixtures can closely mimic blood viscosities at different hematocrit levels

The Immortal Accusation

In the American criminal justice system, accusations have eternal life. Prosecutors, judges, and prison officials regularly consider dismissed charges and even prior acquittals in the defendant’s criminal history when making decisions ranging from the filing of charges to the imposition of punishment. This Article argues that the criminal justice system’s reliance on “accusation evidence” should be understood as furthering that system’s larger allegiance to attaining and preserving findings of guilt. Once the government obtains a guilty plea or verdict, appellate courts rarely overturn convictions based on concerns about the accuracy of the conviction; indeed, post-conviction review procedures often are structured to prevent meaningful consideration of innocence claims. Appellate courts will eventually cease reconsideration of the conviction altogether, even, in many cases, where legitimate questions about the defendant’s guilt remain. But while convictions are eventually laid to rest, accusations that do not result in convictions can be reconsidered forever, in a variety of contexts, by a variety of government actors, applying low or non-existent standards of proof. Once guilt is obtained, the system aims to preserve it; if guilt is eluded, the system will pursue it. This Article begins by reviewing the ways in which the criminal justice system seeks to obtain and maintain convictions. It then discusses the criminal justice system’s reliance on accusation evidence, identifying how uncertainty about the defendant’s culpability in the absence of a conviction drives decision makers to reconsider that outcome and replace it with their own determinations of guilt. It goes on to contrast the systemic reconsideration of convictions with the reconsideration of charges for which no conviction was obtained, using the doctrine of finality as a comparison point. Based on this analysis, it argues that the criminal justice system is structured to obtain and preserve findings of guilt, even if doing so does not advance the pursuit of truth or the conviction of the culpable. This Article then examines the implications of the systemic dedication to the pursuit and preservation of guilt, and suggests ways in which it might, and should, be dismantled

External Organizational Identification, Parasocial Relationships, and Social Media Use

The pervasive use of the Internet for social purposes has led to organizational and social change, as well as social movements online throughout the world. Of particular interest in this study is commitment to organizations by patrons and stakeholders showcased via social media outlets. This research includes a review of organizational identification, parasocial relationships and social media research followed by a detailed description of the method, which included the creation and testing of a questionnaire examining the organizational identification and parasocial relationships of external publics, and their social media use. A hypothesis is put forth suggesting that there is a relationship between social media use and external organizational identification, which was confirmed with a Pearson Product-Moment correlation A research question that sought to discover whether parasocial relationships influence that relationship was asked and results of a mediation analysis suggest that parasocial relationships do mediate the relationship between social media use and external organizational identification. Practical implications for communication researchers and organizations, as well as, suggestions for future research and limitations conclude this research

Impact of Insurance Status on Childhood Immunization Uptake

Economic barriers remain an obstacle to ensuring that children in the United States are protected against vaccine-preventable diseases. Disparities persist despite programs in place to alleviate them, such as the Vaccines for Children program, which provides free vaccines for eligible children. Using data from the 2010 National Immunization Survey, this study addresses whether insurance status has an impact on immunization uptake by investigating associations between vaccine receipt and insurance type, VFC eligibility, and insurance continuity. Logistic regression was performed using possible important factors suggested in the literature. Among children in the national sample, results showed strong associations between up-to-date immunization status and insurance type, VFC eligibility, and insurance continuity, suggesting that additional steps must be taken to alleviate disparities in vaccine receipt. Regression analysis showed child’s age group, insurance continuity, and number of vaccine providers to be the strongest predictors of up-to-date status among children in the national sample

Psychological Functioning and Trait Mindfulness in Urban Youth

The goal of this dissertation was to examine comorbid psychological symptoms experienced by urban minority adolescents, an at-risk and understudied population, to inform screening and intervention efforts for youth at highest risk of developing comorbid disorders and prevent later emotional and behavioral problems. The first study identified youth subgroups experiencing multiple psychological symptoms and compared them by psychosocial factors. Data were analyzed from a sample of 426 Baltimore City 8th grade students using latent profile analysis, which indicated four profiles characterized by concordance or discordance between student- and teacher-reported symptoms. Latent regressions found that the profile with high levels of student- and teacher-reported symptoms had the highest levels of trauma exposure, substance use, and maladaptive coping. The differentiation of the profiles indicates that future research and screening efforts should include information from both students and teachers to maximize the ability to detect students in need of supports. The second manuscript aimed to validate the subgroups identified in the prior study and to examine differences between groups in sex and trait mindfulness. Confirmatory latent profile analysis with a sample of 201 Baltimore City 8th grade students reproduced the same profiles as the first study. Latent regressions found significant differences in sex and trait mindfulness between profiles, and showed more differences in trait mindfulness between profiles for females than for males. These findings indicate that further research is needed to understand sex differences in comorbid psychological symptoms and trait mindfulness in urban youth. The third manuscript aimed to assess the associations between trauma exposures and comorbidity in urban youth, and to explore potential pathways through heart rate variability, using multilevel models with a sample of 112 Baltimore City 8th and 9th grade students. While findings did not reach statistical significance, results revealed potential patterns in the associations between trauma, comorbidity, and heart rate variability. These studies contribute to the literature on comorbidity in at-risk youth by identifying subgroups of urban youth experiencing comorbid psychological symptoms based on the level of concordance and/or discordance between student and teacher reports. Moreover, we were able to further describe urban youth with comorbid symptoms