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Based on first-principles calculation of density functional theory, this study investigates the structural stability, magnetic properties, and electronic properties of the three different phases (i.e. type 1, type 2, and type 3) of OsXCoSi (X=Ti, Zr, Hf) in a new quaternary Heusler alloy series. The corresponding equilibrium lattice constants of each type are optimized, and the change of formation enthalpy and elastic constant phonon spectrum show that the OsXCoSi (X=Ti, Zr, Hf) alloy is thermodynamically, dynamically and mechanically stable. Furthermore, the bonding features of each phase are discussed. It is found that all type 1 structures of OsXCoSi (X=Ti, Zr, Hf) exhibit natural half-metallicity (HM) in equilibrium lattice constant, and their equilibrium lattice constants in the ground state were determined to be 5.909 Å for OsTiCoSi, 6.155 Å for OsZrCoSi, and 6.100 Å for OsHfCoSi. Meanwhile, by testing the alloy under different pressures, the range of the integer magnetic moment non-equilibrium lattice constants for the three alloys OsTiCoSi, OsZrCoSi, and OsHfCoSi are 5.710 Š∼ 6.329 Å, 5.696 Š∼ 6.1557 Å and 5.716 Š∼6.1009 Å, respectively, which is wide and is more close to the practical application for spin-polarized materials. In addition, its magnetic moment is consistent with the values given by the Slater-Pauling rule. Furthermore, the forming of the HM gap is examined by analysing the total and partial density of states, energy bands of alloy's electronic property, with respect to the calculated results. What's more, special attention is paid to the differences of the properties for series Heusler alloys. It is found that the electronics properties distinction is mainly based on valence electron changes. However, the lattice constants are susceptible to size of a nucleus.

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Using first-principles calculations, we predicted three novel superhard semiconducting structures of C8B2N2 with a space group of P3m1. We investigated their mechanical properties and electronic structures up to 100 GPa. These three structures were successfully derived by substituting carbon (C) atoms with isoelectronic boron (B) and nitrogen (N) atoms in the P3m1 phase, which is the most stable structure of BCN and exhibits exceptional mechanical properties. Our results indicated that these structures had superior energy over previously reported t-C8B2N2, achieved by replacing C atoms in the diamond supercell with B and N atoms. To ensure their stable existence, we thoroughly examined their mechanical and dynamical stabilities, and we found that their hardness values reached 82.4, 83.1, and 82.0 GPa, which were considerably higher than that of t-C8B2N2 and even surpassing the hardness of c-BN. Calculations of the electron localization function revealed that the stronger carbon-carbon covalent bonds made them much harder than t-C8B2N2. Additionally, our further calculations of band structures revealed that these materials had indirect bandgaps of 4.164, 4.692, and 3.582 eV. These findings suggest that these materials have the potential to be used as superhard semiconductors, potentially surpassing conventional superhard materials.

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Stimulated by a recent experiment observing successfully two superconducting states with even- and odd-number of electrons in a nanowire topological superconductor as expected from the existence of two end Majorana quasiparticles (MQs) [Albrecht et al., Nature 531, 206 (2016)], we propose a way to manipulate Majorana qubit exploiting quantum tunneling effects. The prototype setup consists of two one-dimensional (1D) topological superconductors coupled by a tunneling junction which can be controlled by gate voltage. We show that the time evolution of superconducting phase difference at the junction under a voltage bias induces an oscillation in energy levels of the Majorana parity states, whereas the level-crossing is avoided by a small coupling energy of MQs in the individual 1D superconductors. This results in a Landau-Zener-Stückelberg (LZS) interference between the Majorana parity states. Adjusting pulses of bias voltage and gate voltage, one can construct a LZS interferometry which provides an arbitrary manipulation of the Majorana qubit.

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The activity and stability of mushroom tyrosinase were studied in ionic liquid (IL)-containing aqueous systems. The effect of three ILs ([BMIm][PF(6)], [BMIm][BF(4)]), and [BMIm][MeSO(4)], where [BMIm] = 1-butyl-3-methylimidazolium) and their inorganic salts (KMeSO(4), KPF(6), and NaBF(4)) on the enzyme performance was investigated by comparing the kinetic (such as K(m), V(max), optimal pH and temperature, and activation energy) and thermostability parameters (including half-lives, deactivation constants, activation energies for enzyme deactivation, DeltaG*, DeltaH*, and DeltaS*) of the enzyme in the absence and presence of the ILs and their anions. Both the three ILs and their inorganic salts were able to trigger enzyme activation. The enzyme could be stabilized by addition of KMeSO(4) and NaBF(4) but destabilized by the presence of all the three ILs. The substrate selectivity of the enzyme was unchanged. The effect of ILs on enzyme performance can be largely attributed to their ionic nature via interaction with the enzyme structure, the substrate, and the water molecules associated with the enzyme, depending on their kosmotropocity, nucleophilicity, and H-bond basicity. The different influences brought from the ILs and their associated ions indicate the cooperative functioning of both cation and anion of the IL in affecting the enzyme performance.

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High concentration of corticosterone (Cort) 0.2 mM was incubated with PC12 cells to simulate the lesion state of brain neurons in depressive illness, it was found that the inulin-type oligosaccharides extracted from Morinda officinalis, inulin-type hexasaccharide (IHS) at the doses of 0.625, 1.25 microM or desipramine (DIM) 0.25, 1 microM protected the PC12 cells from the lesion induced by Cort. With Fura-2/AM labeling assay, DIM 0.25, 1 microM or IHS 2.5, 10 microM attenuated the intracellular Ca2+ overloading induced by Cort 0.1 mM for 48 h in PC12 cells. Using RT-PCR, treatment with Cort 0.1 mM for 48 h decreased the nerve growth factor (NGF) mRNA level in PC12 cells, IHS 5, 10 microM reversed this change. In summary, IHS attenuate the intracellular Ca2+ overloading and thereby up-regulate the NGF mRNA expression in Cort-treated PC12 cells, which may be consisted at least part of the cytopretective effect of IHS. These results also extend evidence for our hypothesis that neuroprotective action is one of the common mechanisms for antidepressants.

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AIM: To explore the possible common action mechanism of antidepressants. METHODS: The cell viability was detected by MTT assay. The intracellular Ca2+ concentration ([Ca2+]i) was measured by Fura 2-AM fluorescence labeling assay. Using RT-PCR, the mRNA level of nerve growth factor (NGF) was also detected. RESULTS: High concentration of corticosterone (0.2 mmol/L) was incubated with PC12 cells to simulate the lesion state of brain neurons in depressive illness. Three main kinds of antidepressants used in clinic [(1) tricyclic antidepressants (TCAs), such as desipramine (DIM) 0.625-10 micromol/L; (2) selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (FLU) 0.625-10 micromol/L; (3) monoamine oxidase inhibitors (MAOIs), such as moclobemide (MOC) 2.5-40 micromol/L] protected cells from the lesion induced by corticosterone. While antipsychotic drug chlorpromazine or anxiolytic agent diazepam 0.4-50 micromol/L had no such effect. Moreover, DIM 1, 5 micromol/L or FLU 1, 5 micromol/L attenuated the [Ca2+]i overload induced by corticosterone 0.1 mmol/L for 48 h in PC12 cells. Furthermore, treatment with DIM or FLU 10 micromol/L for 48 h elevated the NGF mRNA expression in PC12 cells. CONCLUSION: Despite a remarkable structural diversity, the cytoprotective effect can be viewed as the common action pathway of the antidepressants. Moreover, attenuation of the intracellular Ca2+ overload and elevation of neurotrophic factor (such as NGF) expression is one of the mechanisms of cytoprotective effect of antidepressants.

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