This article describes the mercury contaminated sites in Asia. Among the various regions, Asia has become the largest contributor of anthropogenic atmospheric mercury (Hg), responsible for over half ...of the global emission. Based on different emission source categories, the mercury contaminated sites in Asia were divided into various types, such as Hg pollution from Hg mining, gold mining, chemical industry, metal smelting, coal combustion, metropolitan cities, natural resources and agricultural sources. By the review of a large number of studies, serious Hg pollutions to the local environment were found in the area influenced by chemical industry, mercury mining and gold mining. With the probable effects of a unique combination of climatic (e.g. subtropical climate), environmental (e.g. acid rain), economic (e.g. swift growth) and social factors (e.g. high population density), more effort is still needed to understand the biogeochemistry cycle of Hg and associated health effects in Asia. Safer alternatives and cleaner technologies must be developed and effectively implemented to reduce mercury emission; remedial techniques are also required to restore the historical mercury pollution in Asia.
Quinoline and quinazoline alkaloids, two important classes of N‐based heterocyclic compounds, have attracted tremendous attention from researchers worldwide since the 19th century. Over the past 200 ...years, many compounds from these two classes were isolated from natural sources, and most of them and their modified analogs possess significant bioactivities. Quinine and camptothecin are two of the most famous and important quinoline alkaloids, and their discoveries opened new areas in antimalarial and anticancer drug development, respectively. In this review, we survey the literature on bioactive alkaloids from these two classes and highlight research achievements prior to the year 2008 (Part I). Over 200 molecules with a broad range of bioactivities, including antitumor, antimalarial, antibacterial and antifungal, antiparasitic and insecticidal, antiviral, antiplatelet, anti‐inflammatory, herbicidal, antioxidant and other activities, were reviewed. This survey should provide new clues or possibilities for the discovery of new and better drugs from the original naturally occurring quinoline and quinazoline alkaloids.
Emerging evidence suggests that host glycans influence severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we reveal that the receptor-binding domain (RBD) of the spike (S) ...protein on SARS-CoV-2 recognizes oligosaccharides containing sialic acid (Sia), with preference for monosialylated gangliosides. Gangliosides embedded within an artificial membrane also bind to the RBD. The monomeric affinities (K
= 100-200 μM) of gangliosides for the RBD are similar to another negatively charged glycan ligand of the RBD proposed as a viral co-receptor, heparan sulfate (HS) dp2-dp6 oligosaccharides. RBD binding and infection of SARS-CoV-2 pseudotyped lentivirus to angiotensin-converting enzyme 2 (ACE2)-expressing cells is decreased following depletion of cell surface Sia levels using three approaches: sialyltransferase (ST) inhibition, genetic knockout of Sia biosynthesis, or neuraminidase treatment. These effects on RBD binding and both pseudotyped and authentic SARS-CoV-2 viral entry are recapitulated with pharmacological or genetic disruption of glycolipid biosynthesis. Together, these results suggest that sialylated glycans, specifically glycolipids, facilitate viral entry of SARS-CoV-2.
Isoquinoline alkaloids, an important class of N‐based heterocyclic compounds, have attracted considerable attention from researchers worldwide since the early 19th century. Over the past 200 years, ...many compounds from this class were isolated, and most of them and their analogs possess various bioactivities. In this review, we survey the updated literature on bioactive alkaloids and highlight research achievements of this alkaloid class during the period of 2014–2018. We reviewed over 400 molecules with a broad range of bioactivities, including antitumor, antidiabetic and its complications, antibacterial, antifungal, antiviral, antiparasitic, insecticidal, anti‐inflammatory, antioxidant, neuroprotective, and other activities. This review should provide new indications or directions for the discovery of new and better drugs from the original naturally occurring isoquinoline alkaloids.
In an effort to establish a scientific foundation for the computational development of advanced Mg-based alloys, a systematic study of the generalized stacking fault (GSF) energy curves has been ...undertaken. Additionally, the associated stable and unstable stacking and twinning fault energies, ideal shear strengths, and comparative twinnability have been investigated in terms of first-principles calculations for dilute Mg-based alloys of type Mg95X. These GSF properties are predicted using the simple and especially the pure alias shear deformations on the basal (0001) plane and along the 101¯0 direction of the hexagonal close-packed (hcp) lattice. Fourteen alloying elements (X) are considered herein, namely Al, Ca, Cu, La, Li, Mn, Sc, Si, Sn, Sr, Ti, Y, Zn and Zr. The following conclusions are obtained: (i) the fault energies and the ideal shear strengths of Mg95X alloys decrease approximately linearly with an increasing equilibrium volume of X (or Mg95X), with the exceptions being for alloying elements Al, Cu, Si and Zn; (ii) alloying elements Sr and La greatly increase the twin propensity of hcp Mg, while Mn, Ti and Zr exhibit opposite trends; and (iii) the observed variation in GSF properties for hcp Mg caused by alloying elements X can be directly traced to the distribution of the differential charge density (Δρ)—a spherical distribution of Δρ facilitates the redistribution of charge and shear deformation, resulting in lower shear-related properties, such as stacking fault energy and ideal shear strength. Computed GSF properties of Mg95X are shown to agree with available experimental and other theoretical results in the literature.
To follow‐up on our prior Part I review, this Part II review summarizes and provides updated literature on novel quinoline and quinazoline alkaloids isolated during the period of 2009‒2016, together ...with the biological activity and the mechanisms of action of these classes of natural products. Over 200 molecules with a broad range of biological activities, including antitumor, antiparasitic and insecticidal, antibacterial and antifungal, cardioprotective, antiviral, anti‐inflammatory, hepatoprotective, antioxidant, anti‐asthma, antitussive, and other activities, are discussed. This survey should provide new clues or possibilities for the discovery of new and better drugs from the original naturally occurring quinoline and quinazoline alkaloids.
In this article, the authors tried to establish a direct correlation between crystallographic variants and impact toughness, and provided some novel insights into the mechanism of cooling rate on the ...impact toughness of coarse grained heat affected zone (CGHAZ) of offshore engineering steel by means of electron back-scattering diffraction (EBSD) analysis. The results showed that variant selection becomes stronger with an decrease in the cooling rate, resulting in the decline of high angle grain boundaries (HAGBs) and thus lower the impact toughness. Moreover, the variation in impact toughness is mainly correlated to the crystallographic block size. The larger the block size, the lower the impact toughness. By visualizing the crystallographic features, it has been clarified that the transition from Bain zone grouping to close-packed plane grouping with the increase of cooling rate, while the corresponding microstructure changes from granular bainite to lath bainite. Furthermore, it has been found that ~ 25% (number fraction) reconstructed prior austenite grains in simulated CGHAZ present a twin-related structure (austenitic twin), which can enhance the variant selection and displays a negative effect on the formation of HAGBs.
Abstract
Hefei Advanced Light Facility (HALF) is designed as a fourth-generation light source based on the diffraction-limited storage ring (DLSR). The pre-research for this design is complete. Due ...to the smaller beam dynamic aperture, about 6 mm, a novel dual-channel kicker has been purposed and designed, with other two traditional kicker, combined the new injection system bump system. This paper presented the principle and layout and the detail of the novel dual-channel kicker.
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