Dong Wang

Bio: Dong Wang is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Scanning tunneling microscope & Medicine. The author has an hindex of 49, co-authored 491 publications receiving 9970 citations. Previous affiliations of Dong Wang include University of Science and Technology of China & Shanghai University.

Intermolecular dearomative oxidative coupling of indoles with ketones and sulfonylhydrazines catalyzed by I 2 : synthesis of [2,3]-fused indoline tetrahydropyridazines

Abstract: A convergent construction of [2,3]-fused indoline tetrahydropyridazines via an I2/tert-butyl hydroperoxide (TBHP) catalyzed three-component dearomative oxidative coupling of indoles, hydrazines and acetophenone was established in moderate to good yields. This protocol provides a new approach for the synthesis of these biologically interesting fused indolines.

AFM-IR probing the influence of polarization on the expression of proteins within single macrophages.

Abstract: Macrophages are essential in innate immunity and are involved in a variety of biological functions. Due to high plasticity, macrophages are polarized in different phenotypes depending on different microenvironments to perform specific functions. Although many studies have focused on macrophage polarization, few have explored the polarization characteristics of macrophages at the subcellular level, even at nanoscale resolution. Here, we utilize AFM-based infrared spectroscopy (AFM-IR) to investigate the influence of an inducer on the expressed proteins of M1/M2 macrophages (induced by LPS and IL-13, respectively). The results from AFM-IR combined with principal component analysis revealed that the characteristic proteins within M1 contain about 35% antiparallel β-sheets (due to the high expression of TNF-α), while the proteins within M2 are made up of approximately 38.8% α-helices. The corresponding nanoscale chemical mapping demonstrates a remarkably heterogeneous distribution of expressed proteins inside single macrophages. Beside the biochemical properties, the biomechanical properties of macrophages were found to be softened in response to the polarization process.

C3, C6, C17-trisubstituted dammarane type triterpenoid saponin derivative, pharmaceutical composition thereof and applications of derivative in pharmacy

Abstract: The invention provides a dammarane type triterpenoid saponin derivative represented in a general formula I, pharmaceutical composition adopting the dammarane type triterpenoid saponin derivative as an active ingredient, and applications of the dammarane type triterpenoid saponin derivative in preparation of drugs for treating neurological diseases and Alzheimer's disease. R1 in the formula I is hydrogen or glycosyl, R2 is hydrogen or glycosyl, and R3 is the C-20-C-27 site of a dammarane type triterpenoid C17-site side chain.

Effects of Magnesium on Niobium Segregation and Impact Toughness in Cast Alloy 718

Abstract: A program has been conducted on the effects of Mg in cast alloy 718. The results show that small amounts of Mg improves impact toughness and decreases Nb segregation by decreasing secondary dendrite arm spacing which results in less and smaller interdendritic Laves and MC eutectics. Small amounts of Mg produce a more spheroidal as well as a more dispersive MC phase. Impact toughness was found to be related to the refinement of interdendritic segregation of Nb which affects the size, quantity and morphology of Laves and MC phases. Introduction The unique effects of Mg have been determined for many wrought superalloys. Mg has been shown to improve the creep properties and particularly the high temperature ductility due to refinement of the grain boundary carbides and equilibrium segregation. Mg also reduces the detrimental effect of S. Effects of Mg in cast superalloys have recently been investigated and results indicate that Mg improves solidification behaviors and structures. Mg segregates to phase boundaries and refines the interdendritic MC carbides and 1/ eutectic as well as decreasing the quantity of ?( eutectic. A program to study the effect of Mg in cast alloy 718 was conducted. The purpose of this study was to study the effects of Mg on the segregaton behavior of Nb and the morphology distribution of primary Laves and MC carbides. This paper presents the effects of Mg on impact toughness and segregation of Nb in cast alloy 7 18. Experimental Procedure Seven heats of alloy 718 with various contents of Mg were prepared. The materials used for first cycle tests were commercial alloy 718 without Mg (Alloy A) and with Mg of 0.0026% (Alloy B). The content of Nb is as high as 5.25%. The 718 materials used for the second cycle testing have a lower Nb content (4.75%) and varying amounts of Mg (0.000%. 0.0016%, 0.0084% and 0.01 l%, respectively. Investment cast specimens were used for testing. The pour temperature was 1420-1450°C and the mold temperature was 820-840°C. The heat treatment for first cycle tests was llOO”C/l hr/AC + 980°C/1 hr/AC + 720°C/16 hr/AC. The heat treatment for the second cycle tests was 1 lOO’C/l hrs/AC + 97O”C/2 hrs/AC + 72O”C/8 hrs/AC to 62O”C/18 hrs/AC. The morphology of Laves and MC eutectic in alloys with various contents of Mg was characterized. Fracture surface were investigated by SEM to determine the effects of Mg. Quantitative measurements of Laves and MC particles were carried out. Both electron microprobe and EDS analyses were also used in this program. Impact tests were premanely used to follow the resultant structural changes on toughness. Superalloy 718--Metallurgy and Applications Edited by E.A. Loria The Minerals, Metals & Materials Society, 1989 545 Experimental Results and Discussion The results of the impact tests show that Mg increases significantly the impact toughness as shown in Table I. Impact toughness increases with Mg content as illustrated in Figure 1. Microstructural studies show that Mg additions have no influence on grain size, but decreases the secondary dendritic arm spacing as shown in Figure 2. Table I. Impact Toughness of Cast alloy 718 with Various

Shedding light on the cell biology of extracellular vesicles.

Abstract: Extracellular vesicles are a heterogeneous group of cell-derived membranous structures comprising exosomes and microvesicles, which originate from the endosomal system or which are shed from the plasma membrane, respectively They are present in biological fluids and are involved in multiple physiological and pathological processes Extracellular vesicles are now considered as an additional mechanism for intercellular communication, allowing cells to exchange proteins, lipids and genetic material Knowledge of the cellular processes that govern extracellular vesicle biology is essential to shed light on the physiological and pathological functions of these vesicles as well as on clinical applications involving their use and/or analysis However, in this expanding field, much remains unknown regarding the origin, biogenesis, secretion, targeting and fate of these vesicles

Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review.

Abstract: The lithium metal battery is strongly considered to be one of the most promising candidates for high-energy-density energy storage devices in our modern and technology-based society. However, uncontrollable lithium dendrite growth induces poor cycling efficiency and severe safety concerns, dragging lithium metal batteries out of practical applications. This review presents a comprehensive overview of the lithium metal anode and its dendritic lithium growth. First, the working principles and technical challenges of a lithium metal anode are underscored. Specific attention is paid to the mechanistic understandings and quantitative models for solid electrolyte interphase (SEI) formation, lithium dendrite nucleation, and growth. On the basis of previous theoretical understanding and analysis, recently proposed strategies to suppress dendrite growth of lithium metal anode and some other metal anodes are reviewed. A section dedicated to the potential of full-cell lithium metal batteries for practical applicatio...

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Abstract: Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...

Active sites of nitrogen-doped carbon materials for oxygen reduction reaction clarified using model catalysts

Abstract: Nitrogen (N)-doped carbon materials exhibit high electrocatalytic activity for the oxygen reduction reaction (ORR), which is essential for several renewable energy systems. However, the ORR active site (or sites) is unclear, which retards further developments of high-performance catalysts. Here, we characterized the ORR active site by using newly designed graphite (highly oriented pyrolitic graphite) model catalysts with well-defined π conjugation and well-controlled doping of N species. The ORR active site is created by pyridinic N. Carbon dioxide adsorption experiments indicated that pyridinic N also creates Lewis basic sites. The specific activities per pyridinic N in the HOPG model catalysts are comparable with those of N-doped graphene powder catalysts. Thus, the ORR active sites in N-doped carbon materials are carbon atoms with Lewis basicity next to pyridinic N.

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

Abstract: The recent advances in electrocatalysis for oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs) are thoroughly reviewed. This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core–shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts, and metal-free catalysts. The recent development of ORR electrocatalysts with novel structures and compositions is highlighted. The understandings of the correlation between the activity and the shape, size, composition, and synthesis method are summarized. For the carbon-based materials, their performance and stability in fuel cells and comparisons with those of platinum are documented. The research directions as well as perspectives on the further development of more active and less expensive electrocatalysts are provided.