Thermal Properties of Graphene, Carbon Nanotubes and Nanostructured Carbon Materials

Recent years witnessed a rapid growth of interest of scientific and engineering communities to thermal properties of materials. Carbon allotropes and derivatives occupy a unique place in terms of their ability to conduct heat. The room-temperature thermal conductivity of carbon materials span an extraordinary large range - of over five orders of magnitude - from the lowest in amorphous carbons to the highest in graphene and carbon nanotubes. I review thermal and thermoelectric properties of carbon materials focusing on recent results for graphene, carbon nanotubes and nanostructured carbon materials with different degrees of disorder. A special attention is given to the unusual size dependence of heat conduction in two-dimensional crystals and, specifically, in graphene. I also describe prospects of applications of graphene and carbon materials for thermal management of electronics.Comment: Review Paper; 37 manuscript pages; 4 figures and 2 boxe

BASELINE CARDIORESPIRATORY AS A PREDICTOR OF BP STATUS IN INSUFFICIENTLY ACTIVE ADULTS

Zachary S. Leicht1, Nathan R. Weeldreyer1, Marc A. Adams2, Siddhartha S. Angadi, FACSM1. 1University of Virginia, Charlottesville, VA. 2Arizona State University, Phoenix, AZ. Background: Blood pressure and peak oxygen uptake (VO2peak) are strong independent predictors of all-cause and cardiovascular mortality. Individuals with a VO2peak of 8 METs or greater have decreased risk of cardiovascular disease compared to those with a VO2peak less than 8 METs. Increasing physical activity in insufficiently active adults is associated with improvements in both cardiorespiratory fitness (CRF) and blood pressure (BP), however approximately 90% of adults in the United States do not meet current physical activity guidelines. Additionally, the relationship between CRF and the odds of having an elevated blood pressure (SBP ≥ 120 and/or DBP ≥ 80) or hypertension (SBP ≥ 140 and/or DBP ≥ 90) are unknown. Therefore, we determined the odds of having elevated blood pressure or hypertension in individuals stratified based on VO2peak (\u3c 8METS or ≥ 8 METS). Methods: Insufficiently active (as determined by accelerometry) individuals (N=518) underwent blood pressure and anthropometric testing followed by a treadmill-based graded exercise test (modified Balke protocol) with ventilatory gas exchange assessment to determine VO2peak. Only valid VO2peak tests (defined as achieving ≥90% age-predicted heart rate max and RER \u3e 1.05) were used for analyses. Adjusted Logistic Regression examined the role of CRF in whether subjects would have normal (SBP \u3c 120 and DBP \u3c 80) , elevated BP or hypertension. Data are presented as means ± SD or odds ratios with α was set at 0.05. Results: Three hundred and seventy five individuals had BP measured and met the criteria for a valid VO2peak test (age = 44.8 ± 9.1 years; BMI = 32.9 ± 6.6; VO2peak = 24.5 ± 4.8 mL/kg/min; SBP = 121 ± 13; DBP = 81 ± 10 mmHg; Males/Females = 124/251). One-hundred and twenty-seven individuals had normal BP, 164 had elevated BP, and 84 individuals were hypertensive. After adjusting for age and sex, those with a VO2peak less than 8 METs did not have significantly different odds of having elevated BP (OR = 1.3, 95% CI: 0.7 - 2.4, p = 0.33). However, those with a VO2peak less than 8 METs were more likely to be hypertensive compared to individuals with a VO2peak greater than 8 METs (OR = 2.5, 95% CI: 1.2 - 5.2, p = 0.01). Conclusions: Approximately 33.9% of our cohort had a BP that was in the normotensive range, 43.7% had elevated BP, and 22.4% were hypertensive. Importantly, the present study found that low CRF in inactive adults was associated with an increased odds of being hypertensive. This underscores the high CVD burden in this population and the need for targeted interventions to optimize outcomes. Supported by R01CA19891

CHANGES IN BLOOD PRESSURE ACROSS THE LIFESPAN AMONG INSUFFICIENTLY ACTIVE ADULTS IN THE AMERICAN SOUTHWEST

Nathan R. Weeldreyer1, Zachary S. Leicht1, Marc A. Adams2, Siddhartha S. Angadi, FACSM1. 1University of Virginia, Charlottesville, VA. 2Arizona State University, Phoenix, AZ. Purpose: Hypertension is one of the leading risk factors for cardiovascular disease (CVD) and is strongly associated with increased mortality risk. Increasing physical activity (PA) has been shown to reduce the risk of hypertension and CVD, however roughly 90% of US adults don’t meet PA guidelines. Therefore, the purpose of this study was to cross-sectionally assess blood pressure across the lifespan in adults a priori selected for being insufficiently active. Methods: Data from this cross sectional, secondary analysis came from a larger clinical trial that included insufficiently active, mostly overweight/obese (93%) adults from the Phoenix region. Subjects had anthropometric and blood pressure testing performed on them at baseline. Multiple regression was used to describe the relationships between age and systolic (SBP) and diastolic blood pressure (DBP). Additionally, sex differences across adult age-groups and differences between obesity classifications were examined. Data are presented as mean ± SD and α was set at 0.05. Results: Five hundred and sixteen subjects were analyzed (Age: 44.8±9.2 (range 19-60), BMI: 33.8±7.2, SBP: 121±13, DBP: 81±10, M/F: 184/332). Regression models revealed a linear increase in SBP across the lifespan. SBP increased by 0.4 mmHg per year with mean SBP in males being 5 mmHg greater than females. DBP had a curvilinear increase with the greatest increase seen between 19-40 years old and a plateau between 40-60. When dividing the cohort by decades of life, individuals 51-60 years old had SBP ~10 mmHg greater than 19-29 years old and 6 mmHg greater than 30-40 years old (124±13 vs 115±12, p = 0.001; and 124±13 vs 118±13, p \u3c 0.001, respectively). In addition, obese inactive individuals had an SBP 6 mmHg greater than normal weight (122±13 vs. 116±11, p = 0.02) and ~4 mmHg greater than those who were overweight (122±13 vs 119±14, p = 0.03) respectively. Conclusion: Our cross-sectional analyses of insufficiently active adults suggests that there is a linear increase in SBP with age. Males on average have SBP 5 mmHg greater than females. Additionally, obese subjects had greater SBP than those in either the normal or overweight BMI groups. Implications for CVD risk reduction in inactive obese populations will be discussed. Supported by R01CA19891

IMPACT OF A CLINIC-BASED, PRAGMATIC LIFESTYLE INTERVENTION FOR THE MANAGEMENT OF TYPE 2 DIABETES MELLITUS

Nathan R. Weeldreyer1, Matthew Martin2, Mindy McEntee2, Farshad Fani Marvasti3, Rodger Kessler4, Glenn Gaesser, FACSM2, Siddhartha S. Angadi, FACSM1. 1University of Virginia, Charlottesville, VA. 2Arizona State University, Phoenix, AZ. 3University of Arizona, Phoenix, AZ. 4University of Colorado Anschutz, Aurora, CO. BACKGROUND: Type 2 diabetes (T2D) is a common metabolic disorder affecting more than 34 million Americans. The associated hyperglycemia results in substantially increased morbidity and mortality risk. Even though efficacious pharmacotherapies exist, glycemic control remains poor with 33-49% of patients not meeting targets for glycemic control as quantified by HbA1c. This study sought to determine the efficacy of a clinic-based, healthy lifestyle intervention on measures of glycemia and cardiovascular health. METHODS: Patients with T2D (n=20; 56.7±12y; 170±9 cm; 98±22 kg; 33.7±7.2 BMI) with an HbA1c of 7.5-10% not requiring injectable insulin were recruited from the Dignity Health outpatient, family medicine clinic in Phoenix, AZ and underwent a quasi-experimental 3-month lifestyle intervention. Subjects were given a daily à la carte menu of healthy exercise, nutrition, and behavioral options from which to choose from. Exercise options consisted of subjects accumulating 150 minutes of moderate or 75 minutes of vigorous exercise a week utilizing various exercise schemes each day (e.g. 3 x 10 min bouts). The dietary intervention utilized increased fiber and healthy fat intake while avoiding refined and added sugars. This was accomplished by provided healthy food menus, nutritional counseling, and gift cards to local markets. Behavioral interventions utilizing motivational interviewing, acceptance and commitment therapy, and problem-solving therapy were used to help promote behavior change. The intervention was administered to patients by medical assistants in the family medicine clinics. Wilcoxon Signed Rank tests were used to analyze pre-and post-intervention differences. RESULTS: A reduction in HbA1c of 0.5% was observed after the intervention (8.6±0.9 vs. 8.1±1.2% respectively; p= 0.05). Additionally, there was a reduction in waist circumference of 3 cm seen (115.5±12.6 vs. 112.5±15.2 cm; p=0.014). Similarly changes in both body weight (97.7±21.9 vs. 95.6±23.9 kg; p= 0.016) and BMI (33.7±7.2 vs 32.8±7.5 kg/m2; p= 0.028) were observed. CONCLUSIONS: Our pilot data suggest that a lifestyle intervention administered by medical assistants in a family medicine clinic demonstrates improvements in glycemic control, waist circumference, and body mass index. These results remain to be verified in a randomized controlled trial setting. Funding: Dignity Health/Arizona State University Strategic Initiatives Progra

Radicular Cyst in Deciduous Maxillary Molars: A Rarity

Radicular cyst arising from deciduous teeth is exceedingly rare accounting for <1% of all radicular cysts. A total of 122 cases have been reported to date in the English language literature. We present a rare case of a radicular cyst associated with a decayed deciduous maxillary molar tooth without any history of prior pulp therapy. Our aim is to emphasize the recognition of inflammatory radicular lesions associated with deciduous teeth which may adversely impact underlying permanent successor