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The understanding of the formation of silicate oligomers in the initial stage of zeolite synthesis is important. The use of organic structure-directing agents (OSDAs) is known to be a key factor in the formation of different silicate species and the final zeolite structure. For example, tetraethylammonium ion (TEA + ) is a commonly used organic template for zeolite synthesis. In this study, ab initio molecular dynamics (AIMD) simulation is used to provide an understanding of the role of TEA + in the formation of various silicate oligomers, ranging from dimer to 4-ring. Calculated free-energy profiles of the reaction pathways show that the formation of a 4-ring structure has the highest energy barrier (97 kJ/mol). The formation of smaller oligomers such as dimer, trimer, and 3-ring has lower activation barriers. The TEA + ion plays an important role in regulating the predominant species in solution via its coordination with silicate structures during the condensation process. The kinetics and thermodynamics of the oligomerization reaction indicate a more favorable formation of the 3-ring over the 4-ring structure. The results from AIMD simulations are in line with the experimental observation that TEA + favors the 3-ring and double 3-ring in solution. The results of this study imply that the role of OSDAs is not only important for the host–guest interaction but also crucial for controlling the reactivity of different silicate oligomers during the initial stage of zeolite formation.

Aims To assess diabetes care delivery and prevention of short-and long-term diabetes-related complications in patients with type 2 diabetes mellitus (T2DM) in Vietnam. Methods DiabCare Asia is an observational, non-interventional, cross-sectional study of hospital-based outpatient care for patients diagnosed with T2DM. Results A total of 1631 patients (mean age 62.7 years; 58.9% female) participated in the study. The percentage of patients with HbA1c < 7.0% (< 53 mmol/mol) was 36.1% and mean (standard deviation) HbA1c was 7.9 ± 1.8% (63 ± 19 mmol/mol). The proportion of patients using insulin was 40%, at a mean total daily dose of 35.4 U. Apart from dyslipidemia (81.2%) and hypertension (78.4%), the most common diabetes-related complications were peripheral neuropathy (37.9%) and eye complications (39.5%). Current insulin therapy was associated with peripheral vascular disease (odds ratio [OR] = 2.28 [95% confidence interval (CI) 1.68; 3.09]) and eye complications (OR = 1.70 [95% CI 1.37; 2.11]). Conclusion In this sample of patients with T2DM in Vietnam, the majority had poor glycemic and metabolic control. Concerted efforts are needed to optimize control and prevent complications in these patients. Trial registration: NCT02066766