Sun Yat-sen University

About: Sun Yat-sen University is a education organization based out in Guangzhou, Guangdong, China. It is known for research contribution in the topics: Population & Cancer. The organization has 115149 authors who have published 113763 publications receiving 2286465 citations. The organization is also known as: Zhongshan University & SYSU.

Copper(I) 1,2,4-triazolates and related complexes: studies of the solvothermal ligand reactions, network topologies, and photoluminescence properties.

Abstract: One-pot solvothermal treatments of organonitriles, ammonia, and Cu(II) salts yielded Cu(I) and 3,5-disubstituted 1,2,4-triazolates. The organic triazolate components were derived from copper-mediated oxidative cycloaddition of nitriles and ammonia, in which a key intermediate 1,3,5-triazapentadienate was isolated as [Cu(II)(4-pytap)(2)] (4-Hpytap = 2,4-di(4-pyridyl)-1,3,5-triazapentadiene) via controlled solvothermal conditions. This intermediate could also be synthesized by Ni(II)-mediated reactions; however, the final triazoles were obtained only when Cu(II) was employed. Therefore, the reaction mechanism of these reactions was elucidated as follows: nitrile was first attacked by ammonia to form the amidine, which further reacted with another nitrile or self-condensed to yield 1,3,5-triazapentadiene, which was coordinated to two Cu(II) ions in its deprotonated form. A two-electron oxidation of the 1,3,5-triazapentadienate mediated by two Cu(II) ions gave one triazolate and Cu(I) cations. Other in situ ligand reactions, such as C-C bond cleavage and hydrolysis, were also found for the nitriles under these solvothermal conditions. Another remarkable feature of these crystalline Cu(I) triazolates is their simple, typical 3- or 4-connected network topologies. The self-assembly of these nets is presumably controlled by steric hindrance, which is subsequently applied to the rational design of the close-packed 2D networks [Cu(I)(tz)](infinity) and [Ag(I)(tz)](infinity) (Htz = 1,2,4-triazole), as well as the porous 3D network [Cu(I)(etz)](infinity) (Hetz = 3,5-diethyl-1,2,4-triazole). The interesting photoluminescence properties of these coinage d(10) metal complexes were also investigated.

High Statistics Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5-500 GeV with the Alpha Magnetic Spectrometer on the International Space Station

Abstract: A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200 GeV the positron fraction no longer exhibits an increase with energy.

Potential health‐promoting effects of astaxanthin: A high‐value carotenoid mostly from microalgae

Abstract: The ketocarotenoid astaxanthin can be found in the microalgae Haematococcus pluvialis, Chlorella zofingiensis, and Chlorococcum sp., and the red yeast Phaffia rhodozyma. The microalga H. pluvialis has the highest capacity to accumulate astaxanthin up to 4–5% of cell dry weight. Astaxanthin has been attributed with extraordinary potential for protecting the organism against a wide range of diseases, and has considerable potential and promising applications in human health. Numerous studies have shown that astaxanthin has potential health-promoting effects in the prevention and treatment of various diseases, such as cancers, chronic inflammatory diseases, metabolic syndrome, diabetes, diabetic nephropathy, cardiovascular diseases, gastrointestinal diseases, liver diseases, neurodegenerative diseases, eye diseases, skin diseases, exercise-induced fatigue, male infertility, and HgCl2-induced acute renal failure. In this article, the currently available scientific literature regarding the most significant activities of astaxanthin is reviewed.