Quantitative analysis of carbon fluxes for fat biosynthesis in wild-type and IRS-1 knockout brown adipocytes

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2005.Vita.Includes bibliographical references.Excessive fat synthesis and the subsequent dysregulation of lipid metabolism constitute the major pathological factors of obesity and type 2 diabetes through triggering insulin resistance. Thus, controlling fat synthesis by identifying key sites for regulation of lipogenesis and modulating the lipogenic fluxes may provide novel approaches to intervention of the diseases. As a first step to quantitative investigation of lipogenic fluxes from various carbon sources as related to insulin signaling, relative contribution of glucose, glutamine, and acetoacetate to fat biosynthesis in wild-type (WT) and insulin receptor substrate-i knockout (IRS-1 KO) brown adipocytes were analyzed by stable-isotope labeling, GC/MS, and flux estimation. Glutamine contributed more to fatty acid synthesis than glucose in WT cells while glucose's contribution was heavier in IRS-1 KO cells. Unlike the straightforward pathway for lipogenesis from glucose, two possibilities for glutamine's route to fatty acid synthesis have been proposed: glutaminolysis pathway through conventional tricarboxylic acid cycle and a pathway via reductive carboxylation of a-ketoglutarate to isocitrate. These pathways were integrated into a metabolic network model for quantitative estimation of individual lipogenic fluxes. Incubation of the cells with [U-13C] glutamine for 6 hrs led to metabolic and isotopic steady state where individual fluxes of the model were estimated with 95% confidence by least-square fit method.(cont.) Dose dependent repression of estimated net flux of reductive carboxylation by specific inhibition of NADP+-dependent isocitrate dehydrogenase and the subsequent reduction in glutamine's contribution to fatty acid synthesis in WT cells strongly indicated that reductive carboxylation is an important site of regulating glutamine's lipogenic flux. Abolition of this net flux, reduction in glutamine's lipogenic contribution, and concurrent rise in glucose's lipogenic contribution in IRS-1 KO cells were consistent with the importance of reductive carboxylation. Differential effects of lack of insulin signaling on individual lipogenic fluxes suggested that there might be specific sites at which insulin signaling regulates lipogenic utilization of carbon sources. These results revealed the importance of other carbon sources such as glutamine in fat synthesis and the means by which the flux of these carbon sources to fat synthesis can be controlled.by Hun-Tae Yoo.Ph.D

Application of Copula-Based Markov Model to Generate Monthly Precipitation

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

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Prevalence of sarcopenia and sarcopenic obesity in Korean adults: The Korean Sarcopenic Obesity Study (KSOS)

*Context:* Sarcopenic obesity (SO), a combination of excess weight and reduced muscle mass and/or strength, is suggested to be associated with an increased risk of adverse health outcomes. 
*Objectives:* To examine the prevalence and characteristics of Sarcopenic and SO defined by using different indices such as Appendicular Skeletal muscle Mass (ASM)/height^2^ and Skeletal Muscle Index (SMI (%): skeletal muscle mass (kg)/weight (kg) × 100) for Korean adults. 
*Methods:* 591 participants were recruited from the Korean Sarcopenic Obesity Study (KSOS) which is an ongoing prospective observational cohort study. Analysis was conducted in 526 participants (328 women, 198 men) who had complete data on body composition using Dual X-ray absorptiometry and computed tomography. 
*Results:* The prevalence of sarcopenia and SO increases with aging. Using two or more standard deviations (SD) of ASM/height^2^ below reference values from young, healthy adults as a definition of sarcopenia, the prevalence of sarcopenia and SO was 6.3% and 1.3% in men and 4.1% and 1.7% in women over 60 years of age. However, using two or more SD of SMI, the prevalence of sarcopenia and SO was 5.1% and 5.1% respectively in men and 14.2% and 12.5% respectively in women. As defined by SMI, subjects with SO had 3 times the risk of metabolic syndrome (OR = 3.03, 95% confidence interval (CI) = 1.26-7.26) and subjects with non-sarcopenic obesity had approximately 2 times the risk of metabolic syndrome (OR = 1.89, 95% CI = 1.18-3.02) compared with normal subjects. 
*Conclusion:* Obese subjects with relative sarcopenia were associated with a greater likelihood for metabolic syndrome. As Koreans were more obese and aging, the prevalence of SO and its impact on health outcomes are estimated to be rapidly grow. Further research is requested to establish the definition, cause and consequences of SO.
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Friction Tubes to Generate Nanobubble Ozone Water with an Increased Half-Life for Virucidal Activity

Nanobubbles and related technologies are expected to be highly utilized in water resource-based industries such as water purification, crops, horticulture, medicine, bio, and sterilization. Ozone, a chemical with high sterilizing power, is known as a natural substance that is reduced to oxygen and water after reacting with pollutants. Ozone water, which is generated by dissolving ozone in water, has been used in various industrial sectors such as medical care, food, and environment. Due to the unstable molecular state of ozone, however, it is difficult to produce, use, and supply ozone at industrial sites in a stable manner. This study proposed a method for constructing a system that can generate high-concentration ozone water in large quantities using low power in real time and maintaining the concentration of the generated ozone water over the long term. Friction tubes (called 'nanotube') played a key role to generate nanobubble ozone water with an increased half-life for virus killing activity. In addition, the safety of ozone water during its spray into the air was explained, and virucidal activity test cases for the influenza A (H1N1/A/PR8) and COVID-19 (SARS-CoV-2) virus using high-concentration ozone water as well as its technical efficacy were described

SPRINTING SPEED OF ELITE SPRINTERS AT THE WORLD CHAMPIONSHIPS

The purpose of this study was to analyze the sprinting speed of the sprinters during the men's 100 m events at the IAAF World Championships (WC) in order to provide important information to track and field coaches and athletes. Sprinting speed of the sprinters was collected by using laser guns (Laveg Sport, Jenoptik, Germany) during the World Championships in Daegu 2011. Then, data from Osaka 2007 WC and Berline 2009 WC were included in the analysis. The findings indicated that a reduction of a sprinter’s maximum speed is correlated with their performance time (