ABSTRACT
Selective conversion of syngas to value-added olefins has attracted considerable research interest. Regulating product distribution remains challenging, such as achieving higher olefin selectivity, propylene/ethylene (P/E) and olefin/paraffin (O/P) ratios. A new pentasil zeolite Al-IDM-1 with recently approved -ION structure, composed of 17-membered-ring (MR) extra-large lobed pores and intersected 10-MR medium pores, shows a C2-6 = selectivity up to 85 % and a high O/P value of 14 in the conversion of syngas when being combined with Zna Alb Ox oxide. Moreover, for the high-silica Al-IDM-1 with Si/Al ratio of 400, the selectivity of propylene and butene accounts for 88 % in C2-4 = , resulting in high P/E (>4) and butene/ethylene (B/E >3) ratios. The high C3-4 = selectivity is contributed by two main reasons, that is, the relatively weak acidity of Al-IDM-1 zeolite enhances the olefin-based cycle revealed by the probe reactions of methanol-to-propylene (MTP) and 1-hexene cracking, and the rich isolated internal SiOH groups in Al-IDM-1 promote the desorption of C3-4 = , once they are formed inside zeolite pores.
ABSTRACT
Aluminosilicate nanosheets with pure IDM-1 structure, abbreviated as Al-I1, were rapidly synthesized by adjusting the F sources. Through preliminary aging, the length along the b-axis of Al-I1 was precisely tuned in the range of 40-200 nm and meanwhile the competitive growth to the MFI phase was suppressed. With improved mass transport owing to expanded pores and shortened diffusion path along the b-axis, the Al-I1 nanosheets exhibited superior catalytic performance to conventional b-axis oriented ZSM-5 in the methanol-to-propylene (MTP) reaction. The optimal Al-I1-40 catalyst with the thinnest thickness of 40 nm showed a long catalytic lifetime of 67 h and a high propylene selectivity of up to 57.1%.
ABSTRACT
Diabetic retinopathy (DR) has become the leading cause of blindness among adults at working age. Previous studies have implicated circ_0001897 in the development of DR. In this study, we investigated the functional roles and mechanisms of circ_0001897 in high glucose-induced angiogenesis and inflammation. Peripheral blood samples from DR patients and healthy controls were collected to examine circ_0001897 expression, which demonstrated a significant upregulation of circ_0001897 in DR patients. To investigate the functional role and mechanisms of circ_0001897, human retinal microvascular endothelial cells (HRECs) were treated with high glucose (HG) to establish an in vitro DR model of endothelial cells. HG treatment induced the upregulation of circ_0001897 in HRECs, and enhanced cell proliferation, inflammatory responses, as well as in vitro angiogenesis. Circ_0001897 knockdown significantly attenuated the cell proliferation, inflammatory responses, and angiogenesis induced by HG treatment. Mechanistically, circ_0001897 sponged and inhibited the activity of mir-29c-3p, which in turn regulates the downstream target transforming growth factor beta 2 (TGFB2). The effects of circ_0001897 knockdown could be rescued by mir-29c-3p inhibitor or TGFB2 overexpression. Collectively, our data demonstrated the novel role of circ_0001897/mir-29c-3p/TGFB2 axis in regulating HG-induced inflammation and angiogenesis of HRECs. These findings suggest that targeting circ_0001897 could serve as an intervention strategy to ameliorate DR.
