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Bariatric surgery is an effective treatment for morbid obesity and its metabolic related comorbidities; type 2 diabetes, hypertension and hyperlipidaemia.1 However, the literature is scarce regarding the long-term outcome after bariatric surgery, especially among multi-ethnic Asian populations. Considering the growing number of bariatric metabolic surgeries in Asia, we have attempted to provide a regional perspective on 5-year long-term clinical outcomes post bariatric surgery in Singapore. Between 2010 and 2016, all bariatric operative cases were included, and these comprised: laparoscopic sleeve gastrectomy (LSG), 393; laparoscopic Roux-En-Y gastric bypass (RYGB), 125; laparoscopic mini-gastric bypass (MGB), 43. The primary outcome measure was the percentage of excess weight loss (% EWL) at 6 months, 1, 2, 3, 4 and 5 years, with % remission of type 2 diabetes mellitus (T2DM) at 1 year following LSG (49.7%, 61.2%, 56.1%, 47.8%, 40.8% and 47.3%; 82.2%), RYGB (60.2%, 62.1%, 57.6%, 50.1%, 48.7% and 47.7%; 86.9%) and MGB (58%, 68.1%, 62.7%, 66.2%, 64.0%, 65.2%; 71.9%). In conclusion, MGB and RYGB showed the greatest % EWL at 5 years and are recommended for moderate T2DM. LSG is an effective bariatric operation with a high % EWL up to 2 years, and a high remission rate of mild T2DM. The remission rate of T2DM was equally high in all 3 surgical groups, independent of ethnic differences.

There has been little study on the effect of composition or molecular weight on the biodegradation rate of photo-cross-linked biodegradable aliphatic polyesters though such information is important for tissue engineering scaffolds. We have synthesized a new series of photopolymerizable linear poly(epsilon-caprolactone-co-lactide-co-glycolide) diacrylates with different molecular weights (Mn = 1800, 4800, and 9300 Da) and compositions (20%, 40%, and 60% epsilon-CL) and studied their biodegradation rates. The resultant oligomers were amorphous and appeared as viscous liquids at room temperature. Liquid-to-solid polymerization was carried out by UV irradiation in the presence of a photoinitiator. The photocuring yield was high (greater than 95%), and the photo-cross-linked polymers were amorphous and rubbery. Mechanical measurements showed that the polymers can be stretchable or rigid; the high molecular weight/low epsilon-CL network has a strain of 176% and a modulus of 1.66 MPa while the low molecular weight/high epsilon-CL network has a strain of 21% and a modulus of 12.3 MPa. In a 10 week in vitro biodegradation study, the polymers exhibited a two-stage degradation behavior. In the first stage, the polymer weight and strain remained almost constant, but a linear decrease in the Young's modulus (E) and ultimate stress (sigma) were observed. Lower oligomer molecular weight or epsilon-CL content correlated with a faster decrease in Young's modulus. In the second stage, which began when the Young's modulus dropped below 1 MPa, there was rapid weight loss and strain increase. The lower the epsilon-CL content, the earlier the second stage happened. Low molecular weight and high epsilon-CL content correlated with a longer modulus half-life (time for the modulus to degrade to 50% of its initial value). The degradation results suggest principles that may be helpful in predicting the biodegradation behavior of similar polymeric cross-linked networks. Films formed from these new polymers have excellent biocompatibility with smooth muscle cells.

Boron adsorption on 2-0.2-#m size fractions of kaolinite at 25 ~ --- 2~ at pH values between 6.0 and 10.5 was studied. The kaolinite sample was pretreated to remove any surface oxide and hydroxide coatings. The initial concentrations of boron in solution ranged between 2 and 10 mg/liter with either KC104 or Ca(C104)2 as background electrolyte at constant ionic strength of 0.09 _+ 0.01 mole/liter. Boron speciation in equilibrium solutions was calculated by using the chemical equilibrium computer program GEOCHEM. The adsorption of boron on kaolinite in either medium showed similar dependence on pH and initial boron concentrations. Boron adsorption at higher pHs was noticeably higher in Ca(C104)2 medium as compared to KC104 medium. These differences were attributed to the formation and adsorption of CaB(OH4) + ion-pair species.