The reactions of 1,2,4-trimethylbenzene, 1,2,4,5-tetramethylbenzene (durene), pentamethylbenzene, hexamethylbenzene (HMB), ethylbenzene, and cumene were studied on large-pore zeolite HBeta catalysts, either alone or with co-injection of methanol-13 C. The reactivity of the methylbenzenes alone increased with increasing methyl substitution, as did selectivity for propene over ethylene. Disproportionation occurred for all methylbenzenes studied; in the case of HMB, pentamethylbenzene was a major volatile product, and we inferred that the heptamethylbenzenium cation also formed and remained in the catalyst. Substantially higher yields of olefins were obtained when methylbenzenes were co-reacted with methanol-13 C. Ethylbenzene alone was unreactive at 350 °C, but when injected with five equivalents of methanol-13 C, ethylbenzene formed ethylene-12 C 2 with very high selectivity. These and other experiments led to a detailed description of the hydrocarbon pool mechanism for MTO chemistry with side-chain methylation as the predominant route to olefins and the paring reaction as a possible minor pathway.

BackgroundThere is controversy over whether aerobic or resistance exercise is more effective for improving endothelial function in type 2 diabetes mellitus (T2DM). This study was aimed to investigate the effects of an aerobic and resistance training program on endothelial function, and the influences of glycemic control, body weight changes, and aerobic capacity in T2DM.MethodsTotal 40 overweight women with T2DM were assigned into 3 groups: an aerobic exercise group (AEG, n=13), resistance exercise group (REG, n=12), and control group (CG, n=15), and followed either brisk walking for the AEG or resistance band training for the REG, 60 minutes per day, 5 days per week for 12 weeks with monitoring daily activity using accelerometers. We assessed endothelial function by flow-mediated dilation (FMD), and aerobic capacity by oxygen uptake at anaerobic threshold (AT_VO2) at baseline and following training program.ResultsThe mean participants' age was 57.0±6.8 years, and body mass index (BMI) was 27.0±2.3 kg/m2. After intervention, FMD increased by 2.2±1.9% in AEG, which differed from REG and CG (P=0.002), despite of decreased body weight (BW) in both AG and RG (2.8±2.5%, P=0.002; 1.6±2.0%, P=0.017, respectively). A significant increased AT_VO2 and decreased HbA1c were found only in AEG. In all participants, FMD was changed with the significant relations to the AT_VO2 (r=0.348, P=0.035), but not to HbA1c levels or BW.ConclusionAerobic exercise appears to be more beneficial than resistance exercise for improving endothelial function in T2DM. In addition, aerobic capacity could be a better predictor of changes in FMD than BW and glycemic control.

Aerobic exercise increases sRAGE levels along with improvement of various cardiometabolic risk factors in patients with T2DM.

BackgroundOur goal was to investigate the effects of low intensity resistance training on body fat, muscle mass and strength, cardiovascular fitness, and insulin sensitivity in type 2 diabetes.MethodsTwenty-eight overweight women with type 2 diabetes were randomly assigned to a resistance training group (RG, n = 13) or a control group (CG, n = 15). RG performed resistance training using elastic bands, of which strength was equal to 40 to 50% of one repetition maximum (1RM), for three days per week. Each exercise consisted of three sets for 60 minutes. We assessed abdominal fat using computed tomography, muscle mass using dual-energy X-ray absorptiometry, and muscle strength using Keiser's chest and leg press. Insulin sensitivity was measured using the insulin tolerance test, and aerobic capacity was expressed as oxygen uptake at the anaerobic threshold (AT-VO2) before and after the 12-week exercise program.ResultsThe age of participants was 56.4 ± 7.1 years, duration of diabetes was 5.9 ± 5.5 years, and BMI was 27.4 ± 2.5 kg/m2, without significant differences between two groups. During intervention, a greater increase in muscle mass and greater decreases in both total fat mass and abdominal fat were observed in RG compared to those of CG (P = 0.015, P = 0.011, P = 0.010, respectively). Increase in 1RM of upper and lower extremities was observed in the RG (P = 0.004, P = 0.040, respectively), without changes in AT-VO2 and insulin resistance in either group.ConclusionIn conclusion, the low intensity resistance training was effective in increasing muscle mass and strength and reducing total fat mass without change of insulin sensitivity in type 2 diabetic patients.

Aims We examined the effects of physical activity with or without dietary restriction for 3 months on regional fat and insulin sensitivity and compared the effect of total energy expenditure from all levels of physical activity with that of physical activity energy expenditure from moderate-to-vigorous exercise in obese women with Type 2 diabetes.Methods In this randomized, controlled trial, we assessed change of body weight, abdominal visceral fat area, subcutaneous fat area and insulin sensitivity, expressed as K ITT , and monitored total energy expenditure and physical activity energy expenditure using an accelerometer during a 12-week intervention in four groups: control, diet, exercise and diet plus exercise.Results The mean body mass index was 28.0 AE 2.7 kg ⁄ m 2 and the mean duration of diabetes was 8 AE 6 years. Both the diet and diet plus exercise groups showed significant body weight loss compared with the control group (P < 0.05). However, the visceral fat area was reduced only in the diet and exercise group (P = 0.017) and the subcutaneous fat area was reduced only in the diet group (P = 0.009). Mean energy intake was an independent determinant of the change in subcutaneous fat area (P = 0.020) and mean total anergy expenditure was an independent determinant of visceral fat area (P = 0.002). Insulin sensitivity K ITT was associated with physical activity energy expenditure (P = 0.006), energy intake (P = 0.047) and the change in fructosamine level (P = 0.016) but not with changes in body weight, subcutaneous fat area, visceral fat area or adipokine level.Conclusions Exercise had an additive effect to dietary restriction on visceral fat reduction. Visceral fat area was associated with total energy expenditure, but insulin sensitivity was associated with physical activity energy expenditure.