Hua Zhang

Bio: Hua Zhang is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Medicine & Graphene. The author has an hindex of 163, co-authored 1503 publications receiving 116769 citations. Previous affiliations of Hua Zhang include Shenzhen University & Zhengzhou University.

Aphadilactones A–D, Four Diterpenoid Dimers with DGAT Inhibitory and Antimalarial Activities from a Meliaceae Plant

Abstract: Aphadilactones A-D (1-4), four diastereoisomers possessing an unprecedented carbon skeleton, were isolated from the Meliaceae plant Aphanamixis grandifolia. Their challenging structures and absolute configurations were determined by a combination of spectroscopic data, chemical degradation, fragment synthesis, experimental CD spectra, and ECD calculations. Aphadilactone C (3) with the 5S,11S,5'S,11'S configuration showed potent and selective inhibition against the diacylglycerol O-acyltransferase-1 (DGAT-1) enzyme (IC50 = 0.46 ± 0.09 μM, selectivity index > 217) and is the strongest natural DGAT-1 inhibitor discovered to date. In addition, compounds 1-4 showed significant antimalarial activities with IC50 values of 190 ± 60, 1350 ± 150, 170 ± 10, and 120 ± 50 nM, respectively.

Understanding the Formation of the Truncated Morphology of High-Voltage Spinel LiNi0.5Mn1.5O4 via Direct Atomic-Level Structural Observations

Abstract: High-voltage spinel LiNi0.5Mn1.5O4 cathode materials typically exhibit a perfect octahedral morphology; i.e., only the {111} planes are observed. However, a truncated octahedral morphology is sometimes observed with the appearance of both the {100} planes and the {111} planes. The underlying mechanism of this morphological transformation is unclear. CS corrected scanning transmission electron microscopy (STEM) techniques were used to study LiNi0.5Mn1.5O4 samples lifted by a focused ion beam (FIB) to determine the atomic-level crystal and electronic structures of the octahedral and truncated octahedral morphologies. STEM images directly show that the appearance of the {100} planes in the truncated octahedral particles of LiNi0.5Mn1.5O4 is closely associated with the atomic-level migration of Ni and Mn ions in the surface region. The STEM electron energy loss spectroscopy (EELS) confirms the presence of oxygen-deficient and Ni-rich areas, particularly in the region close to the newly formed {100} planes. Th...

Identity of planar defects in the Infinite-layer' copper oxide superconductor

Abstract: THE 'infinite-layer' compound1–3 AcuO2 (where A stands for cations such as strontium or calcium), has the simplest structure of all superconducting copper oxides, with only bare cations separating the CuO2 planes. Accordingly, an understanding of the doping mechanism(s) that lead to superconductivity in this compound may facilitate the elucidation of the same phenomenon in the other copper oxide superconductors. Recently, Azuma and co-workers2,4 observed planar defects in an infinite-layer phase synthesized at high oxygen pressure, and proposed that the defects are A-cation deficient, and lead to superconductivity (with transition temperature Tc≈ 100–110 K) in this compound. Here, based on quantitative X-ray and high-resolution electron-microscopic analysis of the planar defects in (Sr, Ca)CuO2, we propose that the defects consist of a corrugated Sr–O layer substituted for a CuO2 layer, with the incorporation of apical oxygen atoms (which are absent in the parent structure) at roughly half the available sites in the neighbouring Sr layers. This is equivalent to an insertion of a Sr3O2 ± x block in an otherwise infinite-layer sequence. The variable oxygen stoichiometry of our defect model can account for the occurrence of p-type superconductivity (following high-pressure oxygenation), n-type superconductivity (high-pressure reduction) or lack of superconductivity (high-pressure neutral-atmosphere annealing) in this system, depending on the synthesis conditions4.

Super tough bilayer actuators based on multi-responsive hydrogels crosslinked by functional triblock copolymer micelle macro-crosslinkers.

Abstract: Intelligent hydrogels responsive to external stimuli have been widely studied due to their great potentials for applications in artificial muscles, soft robotics, sensors and actuators. However, the weak mechanical properties, narrow response range, and slow response speed of many responsive hydrogels have hindered practical applications. In this paper, tough multi-responsive hydrogels were synthesized by using vinyl-functionalized triblock copolymer micelles as macro-crosslinkers and N-isopropyl acrylamide (NIPAM) and acrylamide (AAm) or 2-(dimethylamino)ethyl methacrylate (DMAEMA) and 2-acrylamido-2-methyl-1-propane-sulfonic acid (AMPS) as monomers. The P(NIPAM-co-AAm) hydrogels presented tensile strength of up to 1.6 MPa and compressive strength of up to 127 MPa and were tunable by changing their formulations. Moreover, the lower critical solution temperature (LCST) of the thermosensitive hydrogels was manipulated in a wide range by changing the molar ratio of NIPAM to AAm. Responsive hydrogel bilayers were fabricated through a two-step synthesis. A second layer of P(DMAEMA-co-AMPS) was synthesized on the first P(NIPAM-co-AAm) layer to obtain a bilayer hydrogel, which was responsive to temperature, pH and ionic strength changes to undergo fast and reversible shape transformation in a few minutes. This kind of strong and tough multi-responsive hydrogel device has broad prospects in soft actuators.

Felsic volcanism as a factor driving the end-Permian mass extinction.

Abstract: The Siberian Traps large igneous province (STLIP) is commonly invoked as the primary driver of global environmental changes that triggered the end-Permian mass extinction (EPME). Here, we explore t...

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.

Abstract: Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.