On the linear convergence of circumcentered isometry methods

Numerical Algorithms - The circumcentered Douglas–Rachford method (C–DRM), introduced by Behling, Bello Cruz and Santos, iterates by taking the circumcenter of associated successive...     

Unpaired 3d Electrons on Atomically Dispersed Cobalt Centres in Coordination Polymers Regulate both Oxygen Reduction Reaction (ORR) Activity and Selectivity for Use in Zinc–Air Batteries

Reversible oxygen conversion is important for various green energy technologies. Herein we synthesize a series of bimetallic coordination polymers by varying the Ni/Co ratio and using HITP (HITP=2,3,6,7,10,11-hexaiminotriphenylene) as the ligand, to interrogate the role of metal centres in modulating the activity of the oxygen reduction reaction (ORR). Co₃HITP₂ and Ni₃HITP₂ are compared. Unpaired 3d electrons in Co₃HITP₂ result in less coplanarity but more radical character. Thus, despite of a reduced crystallinity and conductivity, the best ORR activity, comparable to 20 % Pt/C, is obtained for Co₃HITP₂, showing the 3d orbital configuration of the metal centre promotes ORR. Experimental and DFT studies show a transition of ORR pathway from four-electron for Co₃HITP₂ to two-electron for Ni₃HITP₂. Rechargeable zinc–air batteries using Co₃HITP₂ as the air cathode catalyst demonstrate excellent energy efficiency and stability.     

Antitumor activity on human bladder cancer T-24 cells and composition analysis of the core of Camellia osmantha fruit

Abstract

In this study, antitumor activity and composition analysis of the core of Camellia osmantha fruit were investigated. The cores were extracted by 80% ethanol to obtain the crude extract (TF), which was successively distributed by different concentrations of ethanol with MCI resin to obtain three different parts (Frs 1 to 3). Cytotoxicity activities showed that TF, Fr-2, and Fr-3 exhibited good inhibition against T-24 with IC₅₀ values of 6.7 ± 1.3, 6.9 ± 0.9, and 6.7 ± 1.7 μg/mL, respectively. Fr-3 has a strong inhibitory activity on T-24 cells, mainly due to effectively increasing the release of intracellular calcium ions and reactive oxygen species. In addition, Fr-3 can inhibit T-24 cells migration and invasion. Further composition analysis on Fr-3 was detected by LC-Q-TOFMS implying the main components to be ellagic acid and its derivatives.     

Suppression of friction-induced-vibration in MDoF systems using tangential harmonic excitation

Meccanica - This paper investigates the effects of tangential harmonic excitation on the friction-induced-vibration in multi-degree-of-freedom systems that are coupled in the tangential and normal...     

N‐heterocyclic carbenes as organocatalysts in controlled/living ring‐opening polymerization of O‐carboxyanhydrides derived from l‐lactic acid and l‐mandelic acid

An organocatalytic approach to controlled/living ring‐opening polymerizations (ROPs) of O‐carboxyanhydrides (OCAs) using N‐heterocyclic carbenes (NHCs) as nucleophilic catalysts has been investigated. NHCs with different structures were used in order to compare the catalytic performances in the ROP of OCA of l ‐lactic acid. ¹H NMR, SEC, and MALDI‐TOF MS measurements of the products clearly indicated a controlled/living manner of the polymerization. The controlled/living nature was further confirmed by kinetic and chain extension experiments. Additionally, polylol initiators were used to produce α,ω‐dihydroxy telechelic, 3‐, and 4‐armed star‐shaped polymers. Moreover, star‐shaped diblock copolymer, bearing methyl and phenyl side groups, has been successfully synthesized with OCA/NHC system. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 . 52, 2306–2315