Recent advance of ATP citrate lyase inhibitors for the treatment of cancer and related diseases.

ATP citrate lyase (ACLY), a strategic metabolic enzyme that catalyzes the glycolytic to lipidic metabolism, has gained increasing attention as an attractive therapeutic target for hyperlipidemia, cancers and other human diseases. Despite of continual research efforts, targeting ACLY has been very challenging. In this field, most reported ACLY inhibitors are "substrate-like" analogues, which occupied with the same active pockets. Besides, some ACLY inhibitors have been disclosed through biochemical screening or high throughput virtual screening. In this review, we briefly summarized the cancer-related functions and the recent advance of ACLY inhibitors with a particular focus on the SAR studies and their modes of action. We hope to provide a timely and updated overview of ACLY and the discovery of new ACLY inhibitors.

Coherent interfaces govern direct transformation from graphite to diamond.

Understanding the direct transformation from graphite to diamond has been a long-standing challenge with great scientific and practical importance. Previously proposed transformation mechanisms1-3, based on traditional experimental observations that lacked atomistic resolution, cannot account for the complex nanostructures occurring at graphite-diamond interfaces during the transformation4,5. Here we report the identification of coherent graphite-diamond interfaces, which consist of four basic structural motifs, in partially transformed graphite samples recovered from static compression, using high-angle annular dark-field scanning transmission electron microscopy. These observations provide insight into possible pathways of the transformation. Theoretical calculations confirm that transformation through these coherent interfaces is energetically favoured compared with those through other paths previously proposed1-3. The graphite-to-diamond transformation is governed by the formation of nanoscale coherent interfaces (diamond nucleation), which, under static compression, advance to consume the remaining graphite (diamond growth). These results may also shed light on transformation mechanisms of other carbon materials and boron nitride under different synthetic conditions.

Electronegativity and chemical hardness of elements under pressure.

SignificanceOver the years, many unusual chemical phenomena have been discovered at high pressures, yet our understanding of them is still very fragmentary. Our paper addresses this from the fundamental level by exploring the key chemical properties of atoms-electronegativity and chemical hardness-as a function of pressure. We have made an appropriate modification to the definition of Mulliken electronegativity to extend its applicability to high pressures. The change in atomic properties, which we observe, allows us to provide a unified framework explaining (and predicting) many chemical phenomena and the altered behavior of many elements under pressure.

Ultrahigh-Pressure Magnesium Hydrosilicates as Reservoirs of Water in Early Earth.

The origin of water on the Earth is a long-standing mystery, requiring a comprehensive search for hydrous compounds, stable at conditions of the deep Earth and made of Earth-abundant elements. Previous studies usually focused on the current range of pressure-temperature conditions in the Earth's mantle and ignored a possible difference in the past, such as the stage of the core-mantle separation. Here, using ab initio evolutionary structure prediction, we find that only two magnesium hydrosilicate phases are stable at megabar pressures, α-Mg_{2}SiO_{5}H_{2} and ß-Mg_{2}SiO_{5}H_{2}, stable at 262-338 GPa and >338 GPa, respectively (all these pressures now lie within the Earth's iron core). Both are superionic conductors with quasi-one-dimensional proton diffusion at relevant conditions. In the first 30 million years of Earth's history, before the Earth's core was formed, these must have existed in the Earth, hosting much of Earth's water. As dense iron alloys segregated to form the Earth's core, Mg_{2}SiO_{5}H_{2} phases decomposed and released water. Thus, now-extinct Mg_{2}SiO_{5}H_{2} phases have likely contributed in a major way to the evolution of our planet.

Discovery of carbon-based strongest and hardest amorphous material.

Carbon is one of the most fascinating elements due to its structurally diverse allotropic forms stemming from its bonding varieties (sp, sp 2 and sp 3). Exploring new forms of carbon has been the eternal theme of scientific research. Herein, we report on amorphous (AM) carbon materials with a high fraction of sp 3 bonding recovered from compression of fullerene C60 under high pressure and high temperature, previously unexplored. Analysis of photoluminescence and absorption spectra demonstrates that they are semiconducting with a bandgap range of 1.5-2.2 eV, comparable to that of widely used AM silicon. Comprehensive mechanical tests demonstrate that synthesized AM-III carbon is the hardest and strongest AM material known to date, and can scratch diamond crystal and approach its strength. The produced AM carbon materials combine outstanding mechanical and electronic properties, and may potentially be used in photovoltaic applications that require ultrahigh strength and wear resistance.

Hierarchically structured diamond composite with exceptional toughness.

The well known trade-off between hardness and toughness (resistance to fracture) makes simultaneous improvement of both properties challenging, especially in diamond. The hardness of diamond can be increased through nanostructuring strategies1,2, among which the formation of high-density nanoscale twins - crystalline regions related by symmetry - also toughens diamond2. In materials other than diamond, there are several other promising approaches to enhancing toughness in addition to nanotwinning3, such as bio-inspired laminated composite toughening4-7, transformation toughening8 and dual-phase toughening9, but there has been little research into such approaches in diamond. Here we report the structural characterization of a diamond composite hierarchically assembled with coherently interfaced diamond polytypes (different stacking sequences), interwoven nanotwins and interlocked nanograins. The architecture of the composite enhances toughness more than nanotwinning alone, without sacrificing hardness. Single-edge notched beam tests yield a toughness up to five times that of synthetic diamond10, even greater than that of magnesium alloys. When fracture occurs, a crack propagates through diamond nanotwins of the 3C (cubic) polytype along {111} planes, via a zigzag path. As the crack encounters regions of non-3C polytypes, its propagation is diffused into sinuous fractures, with local transformation into 3C diamond near the fracture surfaces. Both processes dissipate strain energy, thereby enhancing toughness. This work could prove useful in making superhard materials and engineering ceramics. By using structural architecture with synergetic effects of hardening and toughening, the trade-off between hardness and toughness may eventually be surmounted.

Low-energy 3D sp2 carbons with versatile properties beyond graphite and graphene.

Carbon materials with full sp2-hybridized bonding, e.g. zero-dimensional (0D) fullerenes, 1D carbon nanotubes, and 2D graphene, possess outstanding and unparalleled properties, and have unique scientific and technological importance. The theoretical design and experimental exploration of other types of novel sp2 carbon allotropes, especially with 3D architectures, is always a compelling scientific theme. Here we proposed a class of low-energy 3D sp2 carbons with exceptional properties, not only possessing excellent mechanical properties such as high 3D strength, rubber-like ultra-stretchability, and negative Poisson's ratio, but also including the electronic properties of graphite-like metallicity and graphene-like Dirac cone, which are the desirable properties across a broad range of potential applications. Furthermore, a design route was suggested to access these 3D sp2 carbons by the polymerization of edge-functionalized graphene nanoribbon arrays.

Black-Phosphorus-Based Orientation-Induced Diodes.

Despite many decades of research of diodes, which are fundamental components of electronic and photoelectronic devices with p-n or Schottky junctions using bulk or 2D materials, stereotyped architectures and complex technological processing (doping and multiple material operations) have limited future development. Here, a novel rectification device, an orientation-induced diode, assembled using only few-layered black phosphorus (BP) is investigated. The key to its realization is to utilize the remarkable anisotropy of BP in low dimensions and change the charge-transport conditions abruptly along the different crystal orientations. Rectification ratios of 6.8, 22, and 115 can be achieved in cruciform BP, cross-stacked BP junctions, and BP junctions stacked with vertical orientations, respectively. The underlying physical processes and mechanisms can be explained using "orientation barrier" band theory. The theoretical results are experimentally confirmed using localized scanning photocurrent imaging. These orientation-induced optoelectronic devices open possibilities for 2D anisotropic materials with a new degree of freedom to improve modulation in diodes.

Novel magnesium borides and their superconductivity.

With the motivation of searching for new superconductors in the Mg-B system, we performed ab initio evolutionary searches for all the stable compounds in this binary system in the pressure range of 0-200 GPa. We found previously unknown, yet thermodynamically stable, compositions MgB3 and Mg3B10. Experimentally known MgB2 is stable in the entire pressure range 0-200 GPa, while MgB7 and MgB12 are stable at pressures below 90 GPa and 35 GPa, respectively. We predict a reentrant behavior for MgB4, which becomes unstable against decomposition into MgB2 and MgB7 at 4 GPa and then becomes stable above 61 GPa. We find ubiquity of phases with boron sandwich structures analogous to the AlB2-type structure. However, with the exception of MgB2, all other magnesium borides have low electron-phonon coupling constants λ of 0.32-0.39 and are predicted to have Tc below 3 K.

A stable compound of helium and sodium at high pressure.

Helium is generally understood to be chemically inert and this is due to its extremely stable closed-shell electronic configuration, zero electron affinity and an unsurpassed ionization potential. It is not known to form thermodynamically stable compounds, except a few inclusion compounds. Here, using the ab initio evolutionary algorithm USPEX and subsequent high-pressure synthesis in a diamond anvil cell, we report the discovery of a thermodynamically stable compound of helium and sodium, Na2He, which has a fluorite-type structure and is stable at pressures >113 GPa. We show that the presence of He atoms causes strong electron localization and makes this material insulating. This phase is an electride, with electron pairs localized in interstices, forming eight-centre two-electron bonds within empty Na8 cubes. We also predict the existence of Na2HeO with a similar structure at pressures above 15 GPa.

Prediction of a new ground state of superhard compound B6O at ambient conditions.

Boron suboxide B6O, the hardest known oxide, has an Rm crystal structure (α-B6O) that can be described as an oxygen-stuffed structure of α-boron, or, equivalently, as a cubic close packing of B12 icosahedra with two oxygen atoms occupying all octahedral voids in it. Here we show a new ground state of this compound at ambient conditions, Cmcm-B6O (ß-B6O), which in all quantum-mechanical treatments that we tested comes out to be slightly but consistently more stable. Increasing pressure and temperature further stabilizes it with respect to the known α-B6O structure. ß-B6O also has a slightly higher hardness and may be synthesized using different experimental protocols. We suggest that ß-B6O is present in mixture with α-B6O, and its presence accounts for previously unexplained bands in the experimental Raman spectrum.

Superconductivity of novel tin hydrides (Sn(n)H(m)) under pressure.

With the motivation of discovering high-temperature superconductors, evolutionary algorithm USPEX is employed to search for all stable compounds in the Sn-H system. In addition to the traditional SnH4, new hydrides SnH8, SnH12 and SnH14 are found to be thermodynamically stable at high pressure. Dynamical stability and superconductivity of tin hydrides are systematically investigated. I4m2-SnH8, C2/m-SnH12 and C2/m-SnH14 exhibit higher superconducting transition temperatures of 81, 93 and 97 K compared to the traditional compound SnH4 with Tc of 52 K at 200 GPa. An interesting bent H3-group in I4m2-SnH8 and novel linear H in C2/m-SnH12 are observed. All the new tin hydrides remain metallic over their predicted range of stability. The intermediate-frequency wagging and bending vibrations have more contribution to electron-phonon coupling parameter than high-frequency stretching vibrations of H2 and H3.

Synthesis of borophenes: Anisotropic, two-dimensional boron polymorphs.

At the atomic-cluster scale, pure boron is markedly similar to carbon, forming simple planar molecules and cage-like fullerenes. Theoretical studies predict that two-dimensional (2D) boron sheets will adopt an atomic configuration similar to that of boron atomic clusters. We synthesized atomically thin, crystalline 2D boron sheets (i.e., borophene) on silver surfaces under ultrahigh-vacuum conditions. Atomic-scale characterization, supported by theoretical calculations, revealed structures reminiscent of fused boron clusters with multiple scales of anisotropic, out-of-plane buckling. Unlike bulk boron allotropes, borophene shows metallic characteristics that are consistent with predictions of a highly anisotropic, 2D metal.

Nitrogen oxides under pressure: stability, ionization, polymerization, and superconductivity.

Nitrogen oxides are textbook class of molecular compounds, with extensive industrial applications. Nitrogen and oxygen are also among the most abundant elements in the universe. We explore the N-O system at 0 K and up to 500 GPa though ab initio evolutionary simulations. Results show that two phase transformations of stable molecular NO2 occur at 7 and 64 GPa, and followed by decomposition of NO2 at 91 GPa. All of the NO(+)NO3(-) structures are found to be metastable at T = 0 K, so experimentally reported ionic NO(+)NO3(-) is either metastable or stabilized by temperature. N2O5 becomes stable at 9 GPa, and transforms from P-1 to C2/c structure at 51 GPa. NO becomes thermodynamically stable at 198 GPa. This polymeric phase is superconducting (Tc = 2.0 K) and contains a -N-N- backbone.

A novel phase of beryllium fluoride at high pressure.

A previously unknown thermodynamically stable high-pressure phase of BeF2 has been predicted using the evolutionary algorithm USPEX. This phase occurs in the pressure range 18-27 GPa. Its structure has C2/c space group symmetry and contains 18 atoms in the primitive unit cell. Given the analogy between BeF2 and SiO2, silica phases have been investigated as well, but the new phase has not been observed to be thermodynamically stable for this system. However, it is found to be metastable and to have comparable energy to the known metastable phases of SiO2, suggesting a possibility of its synthesis.

Phagraphene: A Low-Energy Graphene Allotrope Composed of 5-6-7 Carbon Rings with Distorted Dirac Cones.

Using systematic evolutionary structure searching we propose a new carbon allotrope, phagraphene [fæ'græfi:n], standing for penta-hexa-hepta-graphene, because the structure is composed of 5-6-7 carbon rings. This two-dimensional (2D) carbon structure is lower in energy than most of the predicted 2D carbon allotropes due to its sp(2)-binding features and density of atomic packing comparable to graphene. More interestingly, the electronic structure of phagraphene has distorted Dirac cones. The direction-dependent cones are further proved to be robust against external strain with tunable Fermi velocities.

Unexpected reconstruction of the α-boron (111) surface.

We report a novel reconstruction of the α-boron (111) surface, discovered using ab initio evolutionary structure prediction, and show that this unexpected neat structure has a much lower energy than the recently proposed (111)-I(R,(a)) surface. In this reconstruction, all single interstitial boron atoms bridge neighboring B(12) icosahedra by polar covalent bonds, and this satisfies the electron counting rule, leading to the reconstruction-induced metal-semiconductor transition. The peculiar charge transfer between the interstitial atoms and the icosahedra plays an important role in stabilizing the surface.

[Infect of pingshen decoction on serum HGF, Cys C and TGF-beta1 diabetic nephropathy in early stage].

Study the serum level of HGF, Cys C and TGF-beta1 in type 2 diabetic nephropathy (DN), the infect of Pingshen decoction on those index. Selected 69 cases of 2 type DN and randomly divided into therapy group (36 cases) and control group (33 cases). The therapy group were treated with Pingshen decoction 1 dose/d, bid po. The control group were treated with NephritisShu tablet, 6 tablet, tid po. 8 weeks was a course. Before and after treatment, we examine the serum level of HGF, Cys C and TGF-beta1 by ELISA and immunonephelometry, and compare with 30 cases of healthy control group. The study demonstrates that before treatment, the serum level of HGF in both groups were significantly lower than healthy control group (P < 0.01), but Cys C, TGF-beta1 were significantly higher (P < 0.01). After treatment, the serum level of HGF of both groups were increased. The serum level of HGF of therapy group were significantly higher than of control group (P < 0.01), but the serum level of Cys C and TGF-beta1 were significantly lower than control group (P < 0.01). The serum level of HGF was correlated negatively with Cys C,TGF-beta1. In control group, the UAER, urine beta2-MG and quantity of 24-hour urine protein were significantly decreased after treatment (P < 0.01). The index of urine of therapy group were significantly lower than control group (P < 0.01). Results indicate that test of serum level of HGF and Cys C,TGF-beta1 of diabetic nephropathy have important clinical significance. Pingshen decoction can effectively intervene in the serum level of HGF and Cys C, TGF-beta1 and index of urine.

Crystal structure prediction and its application in Earth and materials sciences.

Evolutionary algorithms, based on physically motivated forms of variation operators and local optimization, proved to be a powerful approach in determining the crystal structure of materials. This review summarized the recent progress of the USPEX method as a tool for crystal structure prediction. In particular, we highlight the methodology in (1) prediction of molecular crystal structures and (2) variable-composition structure predictions, and their applications to a series of systems, including Mg(BH4)2, Xe-O, Mg-O compounds, etc. We demonstrate that this method has a wide field of applications in both computational materials design and studies of matter at extreme conditions.

New reconstructions of the (110) surface of rutile TiO2 predicted by an evolutionary method.

Reconstructions of the (110) surface of rutile TiO2 (the dominant surface of this important mineral and catalyst) are investigated using the evolutionary approach, resolving previous controversies. Depending on thermodynamic conditions, four different stable reconstructions are observed for this surface. We confirm the recently proposed "Ti2O3-(1×2)" and "Ti2O-(1×2)" reconstructions and predict two new reconstructions "Ti3O2-(1×2)" and "Ti3O3-(2×1)," which match experimental results. Furthermore, we find that surface electronic states are sensitive to reconstructions and, therefore, depend on thermodynamic conditions.