12 research outputs found
Cytotoxic 1,3-Thiazole and 1,2,4-Thiadiazole Alkaloids from Penicillium oxalicum: Structural Elucidation and Total Synthesis
Two new thiazole and thiadiazole alkaloids, penicilliumthiamine A and B (2 and 3), were isolated from the culture broth of Penicillium oxalicum, a fungus found in Acrida cinerea. Their structures were elucidated mainly by spectroscopic analysis, total synthesis and X-ray crystallographic analysis. Biological evaluations indicated that compound 1, 3a and 3 exhibit potent cytotoxicity against different cancer cell lines through inhibiting the phosphorylation of AKT/PKB (Ser 473), one of important cancer drugs target
Diastereoselective synthesis of C‑vinyl glycosides via gold(I)-catalyzed tandem 1,3-acyloxy migration/Ferrier rearrangement
A novel gold-catalyzed C-glycosylation has been developed to gain access to α,(Z)-selective C-vinyl glycosides, starting from readily available glycals and propargylic carboxylate. This reaction involves a tandem intermolecular gold-catalyzed 1,3-acyloxy migration/Ferrier rearrangement with the involvement of allenic ester as the glycosyl acceptor. A wide range of substrate scope with good to excellent yields was achieved with complete diastereoselectivity.Ministry of Education (MOE)National Research Foundation (NRF)Accepted versionWe thank the Ministry of Education (MOE 2013-T3-1-002), National Research Foundation (NRF2016NRF-NSFC002-005), Nanyang Technological University, Singapore (RG14/16), China Scholarship Council (No. 201508420062), and Youth Talent Development Foundation of China Three Gorges University for their financial support. Dr. Yongxin Li and Dr. Ganguly Rakesh in the division of chemistry and biological chemistry, Nanyang Technological University are also acknowl-edged for X-ray analysis
Enhancing cycle life of nickel-rich LiNi0.9Co0.05Mn0.05O2 via a highly fluorinated electrolyte additive - pentafluoropyridine
A highly fluorinated additive, pentafluoropyridine (PFP), is used here to enhance the interfacial stability of the Ni-rich LiNi0.9Co0.05Mn0.05O2 (NCM90) cathode at a cut-off voltage of 4.3 V vs. Li/Li+ at 30 °C. The capacity retention of the NCM90||Li cell is obviously improved from 72.3% to 80.3% after 200 cycles at 1C (1C = 180 mA g-1) when 0.2% PFP is introduced into the baseline electrolyte (1 mol L-1 LiPF6 in ethylene carbonate/diethyl carbonate). The improvement in electrochemical performance could be attributed to the formation of a compact and uniform cathode electrolyte interphase (CEI) layer enriched with F-containing polypyridine moieties and LiF species on the NCM90 particles. This CEI prevents side reactions between the electrode and electrolyte and hinders the corrosion of the cathode caused by HF attack. In addition, the formation of internal particle cracks is somewhat suppressed by the robust CEI, thus prohibiting the irreversible phase transformation and better maintaining the superior lithium-ion diffusion kinetics
Cytotoxic 1,3-Thiazole and 1,2,4-Thiadiazole Alkaloids from Penicillium oxalicum: Structural Elucidation and Total Synthesis
Laparoscopic ureteroneocystostomy with bladder flap for benign ureteral stenosis: our initial experience
Abstract To present our experience with laparoscopic ureteroneocystostomy with bladder flap (LUCBF) for treating benign ureteral stenosis and evaluate its feasibility and efficacy. The clinical data of 27 patients with benign ureteral stenosis who underwent LUCBF were retrospectively analyzed. After identification and excision of the ureteral stenosis segment, the healthy ureteral stump was dissected and incised longitudinally. A U-shaped or spiral bladder flap was harvested from the anterolateral bladder wall for ureteroplasty. All patients underwent LUCBF successfully, including 14 patients were combined with psoas hitch technique, between 90 and 220 min (median, 155 min). The median length of ureteral defect was 6 cm (range, 5–17 cm). The median blood loss was 40 ml (20–150 ml). The median indwelling time of double-J stent was 8 weeks (range, 4–8 weeks). Five patients (10.6%) suffered postoperative complications during the follow-up period (range, 12–48 months), including fever, hematuria, urinary tract infection and recurrent stenosis. The success rate was 96.3% (26/27). Patients with long ureter defects had longer operative time and more blood loss than short ureter defects. LUCBF was a safe and feasible technique for benign ureteral stenosis. Long ureter defect was related to longer operative time and more blood loss
Diastereoselective Synthesis of <i>C</i>‑Vinyl Glycosides via Gold(I)-Catalyzed Tandem 1,3-Acyloxy Migration/Ferrier Rearrangement
A novel gold-catalyzed <i>C</i>-glycosylation has been
developed to gain access to α,(<i>Z</i>)-selective <i>C</i>-vinyl glycosides, starting from readily available glycals
and propargylic carboxylate. This reaction involves a tandem intermolecular
gold-catalyzed 1,3-acyloxy migration/Ferrier rearrangement with the
involvement of allenic ester as the glycosyl acceptor. A wide range
of substrate scope with good to excellent yields was achieved with
complete diastereoselectivity
Effect mechanism of Ni coating layer on the characteristics of Al/steel dissimilar metal brazing
Effect of superoxide dismutase and diethyldi-thicarbamate on the induction of squamous cell carcinoma of lung withmethyl-cholanthren in rats
Numerical analysis on the residual stress distribution and its influence factor analysis for Si3N4/42CrMo brazed joint
Dual resolution cone beam breast CT: A feasibility study
Purpose: In this study, the authors investigated the feasibility of a dual resolution volume-of-interest (VOI) cone beam breast CT technique and compared two implementation approaches in terms of dose saving and scatter reduction