Search

To screen the odorant binding proteins (OBPs) of Tribolium castaneum related to repellent activity and explore the repellent mechanism of terpenoids by studying the interaction between ligands and TcOBPs. Behavior tests indicated that (1R)-(+)-α-Pinene and β-Caryophyllene had repellent activity against T. castaneum. Through homology modeling and molecular docking, we screened TcOBP-9B, which is highly expressed in antennae and has strong interactions with (1R)-(+)-α-Pinene, β-Caryophylne, as target protein for recombinantly expressed. Fluorescence spectra and UV absorption spectra showed that TcOBP-9B had strong bind to (1R)-(+)-α-Pinene and β-Caryophyllene with concentration-dependent in static quenching. Thermodynamic date revealed that they formed stable complexes through van der Waals force, electrostatic and hydrophobic interactions. By fluorescence competitive binding assay, molecular docking and circular dichroism spectra, the binding sites of TcOBP-9B was confirmed as the α-helix, where the ligands were competitively bound to 1-NPN. These results suggested that TcOBP-9B was a significant target protein associated with repellent activity, providing new approach for screening repellents against T. castaneum.

Using the projector augmented wave (PAW) within the Perdew, Burke, and Ernzerhof (PBE) form of generalized gradient approximation (GGA), We present a study of the electronic structure, phase transition, elastic, thermodynamic, and thermoelectric properties of FeRh. We find that FM structure exhibits the largest Fe magnetic moment, which is in accordance with the experimental data and Fe magnetic moment for A-AFM and G-AFM phases, c-AFM, A’-AFM and Ort phases show lower Fe local magnetic moment. Our most stable structure is orthorhombic phase. This conclusion is supported by Zarkevich and Johnson, but contrary to the results of Aschauer et al., Kim et al. and Gruner et al. The obtained phase transition of Ort → c-AFM occurs at ca. 116.5 GPa and c-AFM to A’-AFM phase transition pressure is 119.0 GPa. The compressional, shear and average velocities as well as the bulk and shear moduli increase monotonically with increasing pressure. It is also found that thermal electronic contributions to specific heat are not negligible and contribution rate of electrons to the total thermal conductivity dominant at high temperature. At lower temperature, lattice thermal conductivity KL increases rapidly with the increasing pressure and KL has a moderate increase under pressure at higher temperature. Whereas, electronic thermal conductivity Ke is opposite. Most of the heat is carried by phonons with mean free paths ranging from 10 to 300 nm at 300 K.

BACKGROUND: Apatinib is a small-molecule multitargeted tyrosine kinase inhibitor. Apatinib has demonstrated encouraging antitumor activities. This study aimed to observe the efficacy and safety of apatinib for the treatment of multiple brain micrometastases. CASE SUMMARY: We report two patients with multiple brain micrometastases after failure of second-line treatment. Both patients had extracerebral metastases. When the patients took 250 mg/d apatinib orally, the intracerebral lesions disappeared. The extracerebral lesions were partially alleviated. Both patients had a progression-free survival of more than 12 mo and were still stable. The safety was good. The main adverse events (AEs) were mild hypertension and proteinuria, which could be controlled. CONCLUSION: Apatinib has clear efficacy and good tolerance in patients with multiple brain micrometastases after failure of second-line treatment.

This study was designed to investigate the insecticidal activity of the essential oils (EOs) and extracts from

The objective of this work was to investigate the chemical compositions of the essential oil (EO) extracted from

The effects of orientation and silicon chain length on the electronic transport properties for linear silicon chains sandwiched between two graphene electrodes are investigated by using non-equilibrium Green’s functions combined with density functional theory. Our results demonstrate that the conductance of single silicon chains can hardly be affected by its orientation, as there is negligible difference between the conductance of tilted and un-tilted chains, and the conductance is impacted greatly by the length of chains, i.e. the transmission coefficient is doubled for double chains. The equilibrium conductance of single silicon chains shows even-odd oscillating behavior, and its tendency decreases with the increase of the chain length. The non-equilibrium electronic transport properties for all types of chains are also calculated, and all current–voltage curves of silicon chains show a linear character. The frontier molecular orbitals, the total and projected density of states are used to analy...

Thermoelectric material is a new type of functional material for directly converting heat energy into electric energy, which has an important application prospect in the fields of new energy generation and waste heat recovery. In this paper, the thermoelectric properties of two-dimensional PtS 2 are researched under different strain based on density functional theory calculations. The ZT was obtained by calculating thermal transport properties and electric transport properties. The largest ZT value of Penta-PtS 2 for p-type and n-type are 0.29 and 0.56 respectively under strain 0%, the maximum ZT value of PtS2 can reach to 0.7 by applying strain.

The structural properties and the phase transition for scandium carbide (ScC) have been studied in NaCl (B1), CsCl (B2), ZB (B3), WZ (B4), NiAs (B81), WC (B h ), and Pmmn structures by using the pseudopotential plane-wave method in the framework of the density functional theory. Our theoretical results show that the most stable structure is the B1 phase, contrary to the result of Rahim et al. The phase transitions B1 → Pmmn and Pmmn → B2 are predicted at 83.7 and 109.7 GPa, respectively. At the same time, we find that the B3, B4, B81, and B h phases are not stable over the whole pressure range considered. In particular, the elastic constants of Pmmn-ScC under high pressure are obtained successfully. The effects of pressure on the elastic properties of B1-ScC and Pmmn-ScC are also predicted. The Debye temperatures Θ and the sound velocities of these two structures are estimated from the elastic constants, and by analyzing G/B, the brittle-ductile behavior of ScC is assessed. In addition, the density of states of B1-ScC at high pressures is also discussed.

The pressure-induced structural phase transition of rhenium monocarbon (ReC) is investigated via the projector augmented wave (PAW) method with the generalized gradient approximation (GGA). Using the first-principles calculations, the equilibrium structural parameters of ReC in rocksalt (NaCl), cesium chloride (CsCl), zinc blende (ZB), wurtzite (WZ), nickel arsenide (NiAs) and tungsten carbide (WC) types are successfully obtained, and the results are well consistent with other theoretical data. It is firstly noted that WC-ReC translates into CsCl-ReC at 510.50 GPa by analyzing the enthalpy difference versus pressure. From the calculated elastic constants, the aggregate elastic modulus ( B , G , E ), the Poisson's ratio ( σ ) and the Debye temperature Θ D of WC-type are also derived. It is observed that all the data of WC-ReC obtained increase monotonically with increasing pressure. Meanwhile, the thermodynamic properties of WC-ReC under high temperature and high pressure are investigated applying nonempirical Debye model in the quasi-harmonic approximation.

Phase transition of rhenium mononitride (ReN) in NaCl, CsCl, zincblende (ZB), NbO, wurtzite (WZ), NiAs, WC, PtS, Pmn2 1 and Cmc2 1 structures have been studied by using the projector augmented wave method. It is found that NbO-type structure is the most stable. This conclusion is consistent with the report of Wang et al., while contrary to the results of Zhao et al., Chen et al., Asvini et al., and Hlynsson et al. The phase transition from NbO-type to NiAs-type occurs at ca. 52.8 GPa, which is also in good agreement with that of Wang et al. The elastic constants of NbO- and NiAs-type ReN under high pressure are calculated and found to be increased with the increasing pressures. At the same time, the ductile-brittle behavior is evaluated by Pugh's criteria. Also, we have predicted the density of states and Vickers hardness for NbO and NiAs types of ReN. Finally, the Debye temperature Θ D , thermal expansion α and heat capacity C V for NbO-type structure at high pressures are also derived through the quasi-harmonic Debye model.

The effect of hydrostatic pressure on the structures of HfN at 0 K was investigated by using the projector augmented wave (PAW) within the Perdew–Burke–Ernzerhof (PBE) form of the generalized gradient approximation (GGA). The transition pressure between NaCl (B1) and CsCl (B2) structures is predicted to be 277.3 GPa. This value is consistent with that reported by Kroll, while in contrast to the results obtained by Ojha et al. and Meenaatci et al. Moreover, the elastic properties of B1-HfN and B2-HfN under high pressures are successfully obtained. It is found that the elastic constants, bulk modulus B , shear modulus G , compressional and shear wave velocities increase monotonically with increasing pressure. The Debye temperature Θ calculated from the elastic constants of HfN is in good agreement with the experimental values. The anisotropies of B1-HfN and B2-HfN at zero pressure have also been discussed.

Phase transition, elastic and thermodynamical properties of technetium monocarbide (TcC) in the WC, NiAs, NaCl, CsCl, and ZnS structures have been studied by full-potential linearized augmented-plane-wave (FP-LAPW) theory. From the enthalpy difference between the five structures, we predict that the structural phase transition from WC-type structure to CsCl-type structure occurs at ca. 411.4 GPa. Meanwhile, it is found that the NiAs, NaCl, and ZnS types are not stable phases in whole pressure ranges considered. In particular, for the first time we calculate the elastic properties and phase transition of TcC under high pressures. For WC TcC and CsCl TcC structures, the elastic constants, bulk modulus, shear modulus, and Young's modulus are predicted to increase monotonically with increasing pressure. The Vickers hardness of TcC under high pressure is estimated. The brittle–ductile behavior of TcC has been obtained by Pugh's criteria. Finally, the Debye temperature, isochoric heat capacity and thermal expansion coefficient are predicted by the quasiharmonic Debye model method.

The structural phase transition and elastic properties of Titanium Nitride (TiN) are investigated using density functional theory (DFT) method within the Perdew–Burke–Ernzerhof (PBE) form of generalized gradient approximation (GGA). Our theoretical equilibrium structural parameters of TiN are in good agreement with the available experimental results and other theoretical values. The predicted phase transition from NaCl-type (B1) to CsCl-type (B2) structure occurs at ca. 341.9 GPa. This conclusion is in agreement with that of Ahuja et al., contrary to the calculation of Ojha et al. using a two-body interionic potential theory. In addition, it is found that the zinc-blende type (B3) and WC structures are not stable in the whole pressure range considered. Especially, the elastic properties of B1 and B2 structures for TiN under pressures are studied for the first time. The bulk moduli, shear moduli, compressional and shear wave velocities of B1–TiN and B2–TiN are obtained successfully and these results increase monotonically with increasing pressure. By analyzing of B/G, the brittle-ductile behavior of TiN is assessed. In addition, polycrystalline elastic properties are also obtained successfully for a complete description of elastic properties.

The effects of orientation on the electronic transport properties of C6 monocyclic ring bound to two Al(1 0 0) electrodes are investigated by density functional theory (DFT) combining with non-equilibrium Green’s-function (NEGF) method. It is found that the equilibrium conductance of the system shows an oscillatory behavior with the angle increasing between the ring plane and the transport direction. The changes of coupling strength and charge transfer between the cluster and the electrodes make a massive contribution to the oscillatory behavior. The calculated I–V characteristics for the cluster show different behaviors with different rotation angles. In certain case, the current increases monotonously and nonlinearly. In the other cases, small negative differential resistance (NDR) is observed.

Virtual Maintenance Technology (VMT), characterized with advantages such as high integration, strong interactivity and economical efficiency, has been broadly applied in industrial applications, academic researches and software systems. Through basic elements and vital technologies on virtual maintenance, the advantages and differences among different methods are analyzed and compared in terms of research advances. By summarizing the critical features of virtual maintenance technology, the future directions in this area are pinpointed.

The structural phase transition and elastic properties of zirconium nitride (ZrN) are investigated by using density functional theory (DFT) methods within the Perdew–Burke–Ernzerhof (PBE) form of generalized gradient approximation (GGA). Our calculated equilibrium structural parameters of ZrN are in good agreement with the available experimental data and other theoretical results. The obtained phase transition B1 → B2 at ca. 210.41 GPa. This conclusion is in agreement with that of Hao et al., contrary to the theoretical calculation of Ojha et al. using a two-body interionic potential theory. We also found that the NiAs and WC phases are not stable in the whole pressure range considered. Especially, the elastic properties of B1-ZrN under high pressure are predicted. It is noted that the elastic constants, bulk moduli, shear moduli, compressional and shear wave velocities as well as Debye temperature of B1-ZrN increase monotonically with increasing pressure. By analyzing G/B, the brittle-ductile behavior of ZrN is assessed. In addition, polycrystalline elastic properties are also obtained successfully for a complete description of elastic properties.

The structural, elastic, and thermodynamic properties of the cotunnite-type phase of hafnium dioxide (HfO2) under high pressure are investigated using pseudopotential plane-wave methods within the Perdew–Burke–Ernzerhof (PBE) form of generalized gradient approximation (GGA). The obtained results are consistent well with the experimental data and those calculated by others. The elastic properties under high pressure are studied for the first time. We note that the elastic constants, bulk modulus, shear modulus, Young's modulus, compressional, and shear wave velocities as well as Debye temperature increase monotonically with increasing pressure. By analyzing G/B and Poisson's ratio, the brittle–ductile behavior is assessed. In addition, polycrystalline elastic properties are also obtained successfully for a complete description of elastic properties. Through the quasi-harmonic Debye model, the pressure P and temperature T dependence of the bulk modulus B, variation of the thermal expansion α, heat capacity CV, and Gruneisen constant γ are studied systematically. At low temperatures, CV is proportional to T3, and CV tends to the Dulong–Petit limit at higher temperatures.

The structural phase transition and elastic properties of monoclinic, orthoI and orthoII zirconium dioxide (ZrO2) are investigated by using pseudopotential plane-wave methods within the Perdew–Burke–Ernzerhof (PBE) form of generalized gradient approximation (GGA). Our calculated equilibrium structural parameters of ZrO2 are in good agreement with the available experimental data. On the basis of enthalpy versus pressure data obtained from our theoretical calculations for high pressure, we find that phase transition pressure from monoclinic to orthoI and orthoI to orthoII are ca. 7.94 GPa and 11.58 GPa, respectively, which are in good agreement with the experimental observations. Especially, the elastic properties of orthoII ZrO2 under high pressure are studied for the first time. We note that the elastic constants, bulk moduli, shear moduli, compressional and shear wave velocities as well as Debye temperature of orthoII ZrO2 increase monotonically with increasing pressure. By analyzing G/B, the brittle-ductile behavior of ZrO2 is assessed. In addition, polycrystalline elastic properties are also obtained successfully for a complete description of elastic properties.

The projector augmented wave method is used within the Perdew–Burke–Ernzerhof form of generalized gradient approximation to investigate the effect of hydrostatic pressure on the structures of hafnium metal. The obtained phase transformation pressures and the elastic constants at zero pressure are in excellent agreement with the experimental values. The elastic constants of α-Hf under high pressures are predicted for the first time. We find that the modulus and the averaged aggregate wave velocities increase monotonically with increasing pressure. The Debye temperature of α-Hf is also calculated at different pressures. The obtained result is well-consistent with the available experimental data.

We present a study of the structural phase transition and elastic properties of titanium (Ti) by using the projector augmented wave (PAW) within the Perdew–Burke–Ernzerhof (PBE) form of generalized-gradient approximation (GGA). The calculated phase transition ω → γ at ca. 116.5 GPa, which agrees well with the experimentally observed transition pressure of 116.0 ± 4.0 GPa. However, other theoretical calculations are far from experimental value. We also find that the δ phase is not stable in the whole pressure range considered and phase transition from γ to β phase occurs at 162.4 GPa. This conclusion is in accordance with those of Joshi et al. and Vermal et al., but in disagreement with the experimental results of Vohra et al. and Akahama et al. Especially, the elastic properties of ω -Ti under high pressure are studied for the first time. We note that the compressional and shear wave velocities as well as the bulk B and shear moduli G increase monotonically with increasing pressure. By analyzing R G / B , the brittle–ductile behavior of Ti is assessed. Polycrystalline elastic properties are also obtained successfully for a complete description of elastic properties.

The structure of ZrB2 under high-pressure was predicted by Particle Swarm Optimization method (CALYPSO). We investigated the structure stability, phonon dispersion curve, elasticity, electronic structure and thermodynamic properties of ZrB2 under high-pressure and high-temperature via first-principles calculations. It maintained the hexagonal structure when the pressure lowers below 600 GPa at 0 K, which is confirmed by the calculated phonon dispersion curve. Studies indicate that the elastic modulus and Poisson’s ratio increase monotonically with pressure, as supported by some theoretical and experimental evidences. Calculated anisotropic factors demonstrate that compression and shear isotropy of ZrB2 weakens as the pressure increases. Using the quasi-harmonic approximation Debye model, the Debye temperature, sound velocity, expansion coefficient, thermal capacity under the high-temperature and pressure were also predicted.

The projector augmented wave method (PAW) within the Perdew–Burke–Ernzerhof (PBE) form of generalized gradient approximation (GGA) is applied to investigate the effect of hydrostatic pressure on the structures of titanium metal. In our calculations, the full geometry optimization for all the structures at each volume considered is performed. The phase sequence ω → γ → δ has been obtained and is in good agreement with the experimental results of Vohra et al. and Akahama et al. The obtained phase transition δ → bcc is at ca. 160.9 GPa. This conclusion is in accordance with those of Kutepov et al. and Joshi et al. The quasi-harmonic Debye model for the first time is used to predict phase diagram of α → ω and the result is in better agreement with the experimental data than those from earlier calculations at 300 K.

The elastic constants and thermodynamic properties of c-BN are calculated using the first-principles plane wave method with the relativistic analytic pseudopotential of the Hartwigen, Goedecker and Hutter (HGH) type in the frame of local density approximation and using the quasi-harmonic Debye model, separately. Moreover, the dependences of the normalized volume V/V-0 on pressure P, as well as the bulk modulus B, the thermal expansion alpha, and the heat capacity C-V on pressure P and temperature T are also successfully obtained.

The lattice parameters, elastic constants, bulk modulus and its pressure derivative of c-BN are calculated using a first-principles plane wave method with the relativistic analytic pseudopotential of the Hartwigen, Goedecker and Hutter (HGH)-type and the pseudopotential of Troullier Martins (TM)-type in the frame of local density approximation, and the dependences of bulk modulus on temperature and on pressure are investigated by the quasi-harmonic Debye model. The Debye temperature and the thermal expansion coefficient of c-BN are also calculated. The results obtained are well consistent with the available experimental data and other theoretical results. At zero pressure, the thermal expansion coefficients are about 6.0 x 10(-6) K-1 at T = 1724 K and 6.5 x 10(-6) K-1 at T = 1972 K, respectively, consistent with the experimental data. (c) 2006 Elsevier B.V. All rights reserved.

We investigate the structure and the equation of state of compound MgB(2) at high pressure using the full-potential linearized muffin-tin orbital scheme within the generalized gradient approximation correction in the frame of density functional theory. Through the quasi-harmonic Debye model, in which the phononic effects are considered, we have obtained successfully the bulk modulus and the thermal expansion of MgB(2). (c) 2005 Elsevier B.V. All rights reserved.

The structural and electronic transport properties of GaxNy ([Formula: see text]) clusters are investigated in the framework of density functional theory (DFT). To get their most stable structures, a strategy of particle swarm optimization (PSO) algorithm is adopted. It is found that the most stable cluster’s binding energy and HOMO–LUMO gap energy decrease with Ga atom’s number in cluster increasing. The electronic transport properties of the clusters connected with two Al(100) electrodes are obtained by a method of combining nonequilibrium Green’s function (NEGF) with DFT. Equilibrium conductance of all six-atom GaN cluster is low (less than 0.65 G0), and Ga2N4 has the highest one (0.635 G0). Significant negative differential resistance (NDR) phenomenon is observed in configurations with cluster Ga2N4, Ga3N3 and Ga5N1, and these three clusters have almost the same current value in voltage region from 0.8 V to 1.3 V.

The vertical distribution of aerosol extinction coefficients within winter planetary boundary layer (WPBL) over the observation site are shown in this paper, and the heights of PBL are discussed. The data indicates that the aerosol over the measurement site is almost trapped within PBL and troposphere layer and is rather stable, and the multi-layer structure of the aerosol distribution is obvious.

Using the projector augmented wave (PAW) within the Perdew-Burke-Ernzerhof (PBE) form of the generalized gradient approximation (GGA), we investigate the effect of hydrostatic pressure on the structures of zirconium metal at zero temperature. We obtain the [Formula: see text] transition at around 26.8 GPa, which is in excellent agreement with the experimental values. We also find that the ω phase is most stable at 0 K and 0 GPa. This conclusion is supported by first-principles calculations of Schell et al and Jona et al. The elastic constants of ω-Zr under high pressures are calculated for the first time. We find that the compressional and shear wave velocities increase monotonically with increasing pressure and the results are in good agreement with the available experimental data. The pressure dependences of three anisotropies of elastic waves are also presented.

The finite-temperature density-functional theory and quasiharmonic lattice dynamics are used to calculate the Gibbs free energy and quasiharmonic phonons of the hexagonal-close-packed (hcp) and omega (omega) crystal structures for Zr. The hcp phonon dispersions agree with experiment; the omega phonon dispersions have not been measured yet. From the free energy, the volume thermal expansion coefficients of alpha-Zr are predicted. The calculated volume thermal expansion coefficients for alpha-Zr are in good agreement with the experiment data at T>100 K. Our calculated results found that at zero-temperature the lowest-energy phase is not the omega but the hcp phase. This conclusion is in accordance with the result of Schnell and Albers, but in disagreement with those of Ahuja and Jona and Marcus. The predicted phase boundary of alpha ->omega is in good agreement with the available experiment; however, other theoretical results are far from the experiment at high temperatures.