Comparison of 304 SS, 2205 SS, and 410 SS Corrosion by Sulfate-Reducing Desulfovibrio ferrophilus

Three types of stainless steel (304 SS, 410 SS, and 2205 SS) were evaluated for their corrosion behaviors in microbiologically influenced corrosion (MIC) by Desulfovibrio ferrophilus strain IS5, a relatively new and very corrosive sulfate-reducing bacteria (SRB) strain. The incubation lasted for 7 days in enriched artificial seawater at 28°C and the results showed that 410 SS had a rather large weight loss (6.2 mg/cm2) and a maximum pit depth (118 µm), but 2205 SS and 304 SS did not suffer from significant weight loss or pitting. Electrochemical tests indicated that 2205 SS was slightly more resistant to SRB MIC than 304 SS, while 410 SS was far less resistant.

Association Between Body Mass Index, Its Change And Cognitive Impairment Among Chinese Older Adults: A Community-Based, 9-Year Prospective Cohort Study

Objective To examine the association of baseline body mass index (BMI) and BMI change with cognitive impairment among older adults in China. Methods The study included data from the Chinese Longitudinal Healthy Longevity Study, a national community-based prospective cohort study from 2002-2018. Baseline BMI and BMI change measurements were available for 12,027 adults aged older than 65 years. Cognitive impairment was defined as Chinese version of the Mini Mental State Examination score less than 18. Multivariable Cox proportional hazard model was used.Results Among 12027 participants (mean age was 81.23 years old and 47.48% were male), the proportion of underweight, normal, overweight and obese at baseline was 33.87%, 51.39%, 11.39% and 3.34%, respectively. During an average of 5.9 years’ follow-up, 3086 participants (4.35 per 100 person-years) with incident cognitive impairment were identified. Compared with normal weight group, adjusted hazard ratio (AHR) for cognitive impairment was 0.86 (95% CI 0.75-0.99) among overweight group, whereas corresponding AHR was 1.02 (95% CI 0.94-1.10) in underweight and 1.01 (95% CI 0.80-1.28) in obese. Large weight loss (<-10%) was significantly associated with an increased risk of cognitive impairment (AHR, 1.42, 95% CI 1.29-1.56), compared to stable weight status group (-5%~5%). In the restricted cubic spline models, BMI change showed a L-shaped association with cognitive impairment. Conclusions BMI-defined overweight is associated with a reduced risk of cognitive impairment among Chinese older adults, while large weight loss is associated with increased risk. More attention should be paid to older adults with significant weight loss.

Abstract 16319: Large Weight Loss Improves Left Ventricular Geometry but Not Myocardial Function 6 Months After Bariatric Surgery (the Fatwest Study)

Background: Bariatric surgery causes rapid and large weight loss and improves cardiovascular risk profile, yet the effect on left ventricular (LV) systolic function has been less explored. Methods: In the prospective FatWest (Bariatric Surgery on the West Coast of Norway) study 98 severely obese patients (44±10 years, 72% women, preoperative body mass index [BMI] 41.8±4.8 kg/m 2 , 36% with hypertension) underwent echocardiography before and 5.9 months after gastric bypass surgery. We assessed changes in LV geometry and systolic function by biplane ejection fraction (EF), midwall shortening (MWS) and mitral annular systolic velocity (s′). LV hypertrophy was defined based on LV mass/height 2.7 . Myocardial O 2 demand was derived from the LV mass-wall stress-heart rate product. Results: Patients experienced on average a 10 kg/m 2 reduction in BMI, and a significant drop in heart rate and blood pressure (all p<0.001). LV mass (-12 g) and myocardial O 2 demand improved significantly (all p<0.01). However, LV EF (60 vs. 61%), s’ (8.5 vs. 8.3cm/s) and MWS (16.1 vs. 15.7%) remained unchanged, and 45% of patients had low MWS 6 months after surgery (Figure). In multivariable regression analyses, LV mass reduction was predicted by weight loss and female sex, independent of changes in blood pressure and heart rate (R 2 0.24, p <0.001) while lower myocardial O2 demand was explained by improvement in its three components, particularly lower LV end-systolic wall stress (R 2 0.9, p<0.001). Conclusion: In severely obese patients with normal EF, bariatric surgery induces a significant reduction in BMI, LV mass and myocardial O 2 demand, but no improvement in LV myocardial systolic function 6 months after surgery.

Abstract P251: Weight Change is Associated With Risk of Cardiovascular Mortality Among Singapore Chinese

Introduction: While epidemiologic studies have established overweight and obesity as risk factors of cardiovascular disease (CVD) mortality, findings on the relationship of change in body weight with CVD mortality are inconsistent. Hypothesis: We assessed the hypothesis that weight change was related to CVD mortality among middle-aged to elderly Chinese in Singapore. Methods: We used prospective data from the Singapore Chinese Health Study, a population-based cohort of 63,257 Chinese men and women aged 45-74 years at recruitment (1993-1998). After 5.7 [standard deviation (SD) 1.4] years, we conducted a follow-up interview (1999-2004) among 52,322 surviving subjects in the cohort. Body weight and height were self-reported among 42,328 participants at both baseline and follow-up interviews. Weight change was computed by percentage difference in weight at both assessments relative to weight at baseline, and categorized as moderate-to-large loss (≥10%), small loss (5.1 to 9.9%), stable (±5%), small gain (5.1-9.9%), and moderate-to-large gain (≥10%). Cox proportional hazards regression model was applied to estimate hazard ratio (HR) after controlling for age, gender, dialect group, dietary pattern, smoking status, alcohol consumption, physical activity, hours of sleep and history of diabetes and hypertension. Results: A total of 1,805 CVD deaths were identified during the follow-up until December 31, 2013 [follow-up duration of 11.5 (SD 2.9) years]. Compared to participants with stable weight, those with moderate-to-large weight loss had a 42% higher risk of CVD mortality (HR: 1.42; 95% CI: 1.25-1.61), while those with moderate-to-large weight gain had a 19% higher risk (HR: 1.19; 95% CI: 1.02-1.37). The HR (95% CI) for stroke mortality was 1.77 (1.44-2.18) for moderate-to-large weight loss, and 1.42 (1.12-1.80) for moderate-to-large weight gain. Conversely, for coronary heart diseases (CHD) mortality, only moderate-to-large weight loss was associated with an increased risk (HR: 1.24; 95% CI: 1.05-1.47). The associations were not different by gender or age-group. When stratified by BMI at baseline using 23 kg/m 2 as cutoff for overweight, moderate-to-large weight loss was associated with increased risks of CHD and stroke mortality in both BMI groups. In contrast, moderate-to-large weight gain was only associated with increased risk of stroke mortality but not with CHD mortality in both BMI groups. Conclusions: In conclusion, this study suggested that both moderate-to-large weight loss and weight gain significantly increased risk of CVD mortality among middle-aged to elderly Chinese. This study emphasizes the importance of maintaining stable body weight in middle-aged and elderly populations.

Carbonization and graphitization of polyimide Upilex

Two-step carbonization was found on a polyimide film, Upilex, similar to that observed on another polyimide, Kapton: large weight loss up to about 22 wt. % and linear shrinkage along the film surface to 30% in a narrow temperature range from 500 to 650 °C, and an additional small weight loss and shrinkage in a wide range between 700 and 1000 °C. The yield of carbonization agreed roughly with that calculated by assuming the release of non-carbon atoms as simple species of CO, O2, and N2. A 25 μm Upilex film yielded a relatively high degree of graphitization after heat treatment at 3000 °C: a layered structure under SEM, high magnetoresistance, and a sharp 002 x-ray diffraction peak at a d-spacing of 0.336 nm. The degree of graphitization was lower than for a similar Kapton film, which is attributed to the lack of flatness in the Upilex molecule. A very much lower degree of graphitization was observed for 50 μm Upilex films. This difference is tentatively attributed to constraints that must have influenced the orientation of the Upilex molecules near the surface of the films as they were formed.

Body Composition and Aerobic Capacity in Morbidly Obese Females

This investigation quantified body composition and aerobic capacity and examined the interrelationships of these measures in 20 morbidly obese females (M age = 34.6 yrs) prior to gastric bypass surgery. Fifteen subjects were hydrostatically weighed at residual lung volume in order to determine body composition. Eighteen subjects performed a maximal modified progressive treadmill test to determine aerobic capacity. Results indicated that the 15 subjects who were weighed hydrostatically were heavier (M wt = 132.34 kg) and fatter (M % fat = 53.18) than any previously described individuals. Relative weight, which is used as a criterion to determine surgery eligibility, was not significantly (p > .05) correlated to percent body fat. Mean aerobic capacity (V̇O2 = 14.99 ml • kg-1 mir-1) was comparable to Class III cardiac patients and was limited by the individuals’ extreme body weight. Since relative weight was shown to be an insensitive measure of obesity, it is recommended that percent fat be measured and used as a means to determine eligibility for gastric bypass surgery. Further study of these individuals is warranted in order to determine what effects large weight loss following surgery will have on parameters of body composition and aerobic capacity. Understanding how large weight loss affects these parameters will aid in designing effective postsurgical exercise rehabilitative programs for future patients.