Investigation of Scramjet Flowfield Temperatures at the Boundary Layer with Hyperspectral Imaging

Within the domain of chemical propulsion, the fields of combustion diagnostics and computational fluid dynamics each have a long history, and both have led to a better understanding of complex phenomena yielding practical improvements in propulsion systems. As more exotic forms of propulsion are developed, the importance of -- and often the challenges with -- both diagnostic and simulation capabilities also increase. In the case of scramjet combustion, these challenges primarily arise from the highly turbulent environment in the combustion cavity, and the high-speed, compressible nature of the flowfield. Efforts are underway to develop computer models of scramjet combustion environments to better understand the evolution of the flow field and heat transfer to the walls during combustion. This thesis effort experimentally supports these goals. Specifically, hyperspectral imaging measurements of an optically accessible scramjet were collected for different fueling rates. The primary focus was characterization the magnitude and dynamics of the outer window temperature in its response to combustion of different fueling rate. The outer window temperature was estimated via the radiometric brightness temperature -- a quantitative measure of infrared radiant emissions -- between 2000 cm-1 \u3c ~v \u3c 2250 cm-1 where the emissivity of the infrared-grade fused silica window is near unity and atmospheric absorption effects are minimal. Examining the radiant window emissions over a range of frequencies between 2500 cm-1 \u3c ~v \u3c4000 cm1, the spectral region in which the window transitions from opaque to transparent, reveals information related to the temperature gradient normal to the line-of-sight. A simple one-dimensional, numerical heat transfer model is used along with a spectral model for the window to interpret the temporal dynamics of brightness temperature in different spectral bands. Inferring the actual temperature profile would require temperature-dependent optical properties of fused silica over a broad, high-temperature regime, and at present these are unavailable. This work indicates there would be value in obtaining this optical data so that hyperspectral measurements of the scramjet could be used to quantify heat transfer to the side window. The window represents an important and dynamic boundary condition, and these hyperspectral measurements could be used to validate numerical simulations. Other work in this thesis effort explores qualitative differences in flowfield turbulence under different fueling conditions, and in principle this turbulence characterization could also be used to for comparisons with numerical simulations

Low physiologic oxygen tensions reduce proliferation and differentiation of human multipotent mesenchymal stromal cells

<p>Abstract</p> <p>Background</p> <p>Human multipotent mesenchymal stromal cells (MSC) can be isolated from various tissues including bone marrow. Here, MSC participate as bone lining cells in the formation of the hematopoietic stem cell niche. In this compartment, the oxygen tension is low and oxygen partial pressure is estimated to range from 1% to 7%. We analyzed the effect of low oxygen tensions on human MSC cultured with platelet-lysate supplemented media and assessed proliferation, morphology, chromosomal stability, immunophenotype and plasticity.</p> <p>Results</p> <p>After transferring MSC from atmospheric oxygen levels of 21% to 1%, HIF-1α expression was induced, indicating efficient oxygen reduction. Simultaneously, MSC exhibited a significantly different morphology with shorter extensions and broader cell bodies. MSC did not proliferate as rapidly as under 21% oxygen and accumulated in G₁phase. The immunophenotype, however, was unaffected. Hypoxic stress as well as free oxygen radicals may affect chromosomal stability. However, no chromosomal abnormalities in human MSC under either culture condition were detected using high-resolution matrix-based comparative genomic hybridization. Reduced oxygen tension severely impaired adipogenic and osteogenic differentiation of human MSC. Elevation of oxygen from 1% to 3% restored osteogenic differentiation.</p> <p>Conclusion</p> <p>Physiologic oxygen tension during <it>in vitro </it>culture of human MSC slows down cell cycle progression and differentiation. Under physiological conditions this may keep a proportion of MSC in a resting state. Further studies are needed to analyze these aspects of MSC in tissue regeneration.</p

West Nile virus in overwintering Culex mosquitoes, New York City, 2000.

After the 1999 West Nile (WN) encephalitis outbreak in New York, 2,300 overwintering adult mosquitoes were tested for WN virus by cell culture and reverse transcriptase-polymerase chain reaction. WN viral RNA and live virus were found in pools of Culex mosquitoes. Persistence in overwintering Cx. pipiens may be important in the maintenance of WN virus in the northeastern United States

Health-related quality of life of Adolescent and Young Adult Cancer Survivors before and during the COVID-19 pandemic::Longitudinal improvements on social functioning and fatigue

The health-related quality of life (HRQoL) among long-term Adolescent and Young Adult Cancer Survivors (AYACS) and an age- and sex-matched normative population was examined. Although the HRQoL of AYACS was worse compared to the normative population before and during the COVID-19 pandemic, the scores of AYACS improved over time in contrast to the normative population. Presumably, AYACS are used to adjusting their lives to stressful life events. Furthermore, the lockdown may have been beneficial for AYACS who face difficulties fully participating in society due to the impact of cancer. AYACS who encounter HRQoL issues could benefit from support interventions to empower them and build resilience

Adherence to the World Cancer Research Fund/American Institute for Cancer Research recommendations for cancer prevention in adolescent and young adult (AYA) cancer survivors:results from the SURVAYA study

Purpose: For adolescent and young adult (AYA) cancer survivors with a good prognosis, having a healthy lifestyle prevents morbidity and mortality after treatment. The aim of this study was to investigate the prevalence of (un)healthy lifestyle behaviors and related determinants in AYA cancer survivors. Methods: A population-based, cross-sectional study was performed among long-term (5–20 years) AYA cancer survivors (18–39 years old at diagnosis) registered within the Netherlands Cancer Registry. Self-reported questionnaires data about health behaviors were used to calculate the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) adherence score. Associations between the score and clinical/sociodemographic determinants of (un)healthy behaviors were investigated using logistic regression models. Results: The mean WCRF/AICR score was low to moderate, 3.8 ± 1.2 (0.5–7.0) (n = 3668). Sixty-one percent adhered to “limit the consumption of sugar sweetened drinks,” 28% to “be a healthy weight,” 25% to “fruit and vegetable consumption,” and 31% to “limit alcohol consumption.” Moderate and high adherence were associated with being a woman (ORmoderate = 1.46, 95% CI = 1.14–1.85, and ORhigh = 1.87, 95% CI = 1.46–2.4) and highly educated (ORmoderate = 1.54, 95% CI = 1.30–1.83, and ORhigh = 1.87, 95% CI = 1.46–2.4). Low adherence was associated with smoking (ORmoderate = 0.68, 95% CI = 0.50–0.92, and ORhigh = 0.30, 95% CI = 0.21–0.44) and diagnosis of germ cell tumor (ORmoderate = 0.58, 95% CI = 0.39–0.86, and ORhigh = 0.45, 95% CI = 0.30–0.69). Conclusions: Adherence to the 2018 WCRF/AICR lifestyle recommendations was low to moderate, especially regarding body weight, fruit, vegetables, and alcohol consumption. Men, current smokers, lower-educated participants, and/or those diagnosed with germ cell tumors were less likely to have a healthy lifestyle. Implications for Cancer Survivors: Health-promotion programs (e.g., age-specific tools) are needed, focusing on high-risk groups.</p

Adherence to the World Cancer Research Fund/American Institute for Cancer Research recommendations for cancer prevention in adolescent and young adult (AYA) cancer survivors:results from the SURVAYA study

Purpose: For adolescent and young adult (AYA) cancer survivors with a good prognosis, having a healthy lifestyle prevents morbidity and mortality after treatment. The aim of this study was to investigate the prevalence of (un)healthy lifestyle behaviors and related determinants in AYA cancer survivors. Methods: A population-based, cross-sectional study was performed among long-term (5–20 years) AYA cancer survivors (18–39 years old at diagnosis) registered within the Netherlands Cancer Registry. Self-reported questionnaires data about health behaviors were used to calculate the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) adherence score. Associations between the score and clinical/sociodemographic determinants of (un)healthy behaviors were investigated using logistic regression models. Results: The mean WCRF/AICR score was low to moderate, 3.8 ± 1.2 (0.5–7.0) (n = 3668). Sixty-one percent adhered to “limit the consumption of sugar sweetened drinks,” 28% to “be a healthy weight,” 25% to “fruit and vegetable consumption,” and 31% to “limit alcohol consumption.” Moderate and high adherence were associated with being a woman (ORmoderate = 1.46, 95% CI = 1.14–1.85, and ORhigh = 1.87, 95% CI = 1.46–2.4) and highly educated (ORmoderate = 1.54, 95% CI = 1.30–1.83, and ORhigh = 1.87, 95% CI = 1.46–2.4). Low adherence was associated with smoking (ORmoderate = 0.68, 95% CI = 0.50–0.92, and ORhigh = 0.30, 95% CI = 0.21–0.44) and diagnosis of germ cell tumor (ORmoderate = 0.58, 95% CI = 0.39–0.86, and ORhigh = 0.45, 95% CI = 0.30–0.69). Conclusions: Adherence to the 2018 WCRF/AICR lifestyle recommendations was low to moderate, especially regarding body weight, fruit, vegetables, and alcohol consumption. Men, current smokers, lower-educated participants, and/or those diagnosed with germ cell tumors were less likely to have a healthy lifestyle. Implications for Cancer Survivors: Health-promotion programs (e.g., age-specific tools) are needed, focusing on high-risk groups.</p