Atomistic insight into the promising thermoelectric performance of the copper-based ternary phosphide CaCuP.

A first-principles study on the thermoelectric properties of the copper-based ternary phosphide CaCuP is presented. Self-energy relaxation time approximation and unified theory for lattice transport provide an accurate description of electron-phonon and phonon-phonon scattering. Our work provides an atomistic insight into its high thermoelectric performance, highlighting that nano-structuring can increase the thermoelectric figure of merit by reducing the lattice thermal conductivity.

First-principles study on structural, electronic and optical properties of halide double perovskite CsAgBX (B = In, Sb; X = F, Cl, Br, I).

All-inorganic halide double perovskites (HDPs) attract significant attention in the field of perovskite solar cells (PSCs) and light-emitting diodes. In this work, we present a first-principles study on structural, elastic, electronic and optical properties of all-inorganic HDPs CsAgBX (B = In, Sb; X = F, Cl, Br, I), aiming at finding the possibility of using them as photoabsorbers for PSCs. Confirming that the cubic perovskite structure can be formed safely thanks to the proper geometric factors, we find that the lattice constants are gradually increased on increasing the atomic number of the halogen atom from F to I, indicating the weakening of Ag-X and B-X interactions.

High thermoelectric performance in metal phosphides MP (M = Co, Rh and Ir): a theoretical prediction from first-principles calculations.

Although metal phosphides have good electronic properties and high stabilities, they have been overlooked in general as thermoelectrics based on expectation of high thermal conductivity. Here we propose the metal phosphides MP (M = Co, Rh and Ir) as promising thermoelectrics through first-principles calculations of their thermoelectric properties. By using lattice dynamics calculations within unified theory of thermal transport in crystal and glass, we obtain the lattice thermal conductivities of MP as 0.

Improving the stability of hybrid perovskite FAPbI by forming 3D/2D interfaces with organic spacers.

Interfaces composed of three-dimensional (3D) and 2D organic-inorganic hybrid formamidinium lead iodide (FAPbI) linked by organic spacers (OSs) are studied using first-principles calculations. The OS cations with aromatic rings, like phenylethylammonium and anilinium (AN), are found to be more favourable for enhancing the stability of the 3D/2D interface than butylammonium with aliphatic chains. The AN-based interface shows the highest resistance to penetration of water molecules.

First-principles study on structural, electronic, magnetic and thermodynamic properties of lithium ferrite LiFeO.

Lithium ferrite, LiFeO (LFO), has attracted great attention for various applications, and there has been extensive experimental studies on its material properties and applications. However, no systematic theoretical study has yet been reported, so understanding of its material properties at the atomic scale is still required. In this work, we present a comprehensive investigation into the structural, electronic, magnetic and thermodynamic properties of LFO using first-principles calculations.

Effect of roscovitine pretreatment for increased utilization of small follicle-derived oocytes on developmental competence of somatic cell nuclear transfer embryos in pigs.

The objective of this study was to evaluate the effect of roscovitine pretreatment on the number of matured oocytes per ovary available for somatic cell nuclear transfer (SCNT) and their developmental competence. Irrespective of reproduction status (prepuberty/puberty), the average number of small follicles per ovary (19.3/17.

Effect of vacancy concentration on the lattice thermal conductivity of CHNHPbI: a molecular dynamics study.

Hybrid halide perovskites are drawing great interest for photovoltaic and thermoelectric applications, but the relationship of thermal conductivities with vacancy defects remains unresolved. Here, we present a systematic investigation of the thermal conductivity of perfect and defective CHNHPbI, performed using classical molecular dynamics with an -derived force field. We calculate the lattice thermal conductivity of perfect CHNHPbI as the temperature increases from 300 K to 420 K, confirming a good agreement with the previous theoretical and experimental data.

Enhancing the Photocatalytic Hydrogen Evolution Performance of the CsPbI/MoS Heterostructure with Interfacial Defect Engineering.

Developing highly efficient photocatalysts for the hydrogen evolution reaction (HER) by solar-driven water splitting is a great challenge. Here, we study the atomistic origin of interface properties and the HER performance of all-inorganic iodide perovskite β-CsPbI/2H-MoS heterostructures with interfacial vacancy defects using first-principles calculations. Both CsI/MoS and PbI/MoS heterostructures have strong binding and dipole moment, which are enhanced by interfacial iodine vacancies ().

First-principles study on structural, electronic and optical properties of perovskite solid solutions KB Mg I (B = Ge, Sn) toward water splitting photocatalysis.

Perovskite materials have been recently attracting a great amount of attention as new potential photocatalysts for water splitting hydrogen evolution. Here, we propose lead-free potassium iodide perovskite solid solutions KBI with B-site mixing between Ge/Sn and Mg as potential candidates for photocatalysts based on systematic first-principles calculations. Our calculations demonstrate that these solid solutions, with proper Goldschmidt and octahedral factors for the perovskite structure, become stable by configurational entropy at finite temperature and follow Vegard's law in terms of lattice constant, bond length and elastic constants.

First-principles study on the elastic, electronic and optical properties of all-inorganic halide perovskite solid solutions of CsPb(Br Cl ) within the virtual crystal approximation.

All-inorganic halide perovskites have drawn significant attention for optoelectronic applications such as solar cells and light-emitting diodes due to their excellent optoelectronic properties and high stabilities. In this work, we report a systematic study on the material properties of all-inorganic bromide and chloride perovskite solid solutions, CsPb(Br Cl ), varying the Cl content from 0 to 1 with an interval of 0.1 by applying the first-principles method within the virtual crystal approximation.

Superior thermoelectric properties of ternary chalcogenides CsAgQ (Q = Te, Se) predicted using first-principles calculations.

Tailoring novel thermoelectric materials (TEMs) with a high efficiency is challenging due to the difficulty in realizing both low thermal conductivity and high thermopower factor. In this work, we propose ternary chalcogenides CsAgQ (Q = Te, Se) as promising TEMs based on first-principles calculations of their thermoelectric properties. Using lattice dynamics calculations within self-consistent phonon theory, we predict their ultralow lattice thermal conductivities below 0.

Interfacial Enhancement of Photovoltaic Performance in MAPbI/CsPbI Superlattice.

Perovskite solar cells have continued to fascinate over the past decade due to fast increasing power conversion efficiency and very low fabrication cost but still suffered from poor stability. Interface engineering is evolved to be one of the most promising solutions to the instability problem. In this work, we perform a first-principles study on the MAPbI/CsPbI interface system, aiming at clarifying the underlying mechanism of interfacial enhancement of solar cell performance.

Computational prediction of structural, electronic, and optical properties and phase stability of double perovskites KSnX (X = I, Br, Cl).

The vacancy-ordered double perovskites KSnX (X = I, Br, Cl) attract significant research interest due to their potential applications as light absorbing materials in perovskite solar cells. However, deeper insight into their material properties at the atomic scale is currently lacking. Here we present a systematic investigation of the structural, electronic, and optical properties and phase stabilities of the cubic, tetragonal, and monoclinic phases based on density functional theory calculations.

Interface Engineering in Hybrid Iodide CHNHPbI Perovskites Using Lewis Base and Graphene toward High-Performance Solar Cells.

Photovoltaic solar cells based on organic-inorganic hybrid halide perovskites have achieved a substantial breakthrough via advanced interface engineering. Reports have emphasized that combining the hybrid perovskites with the Lewis base and/or graphene can definitely improve the performance through surface trap passivation and band alignment alteration; the underlying mechanisms are not yet fully understood. Here, using density functional theory calculations, we show that upon the formation of CHNHPbI interfaces with three different Lewis base molecules and graphene, the binding strength with S-donors thiocarbamide and thioacetamide is higher than with O-donor dimethyl sulfoxide, while the interface dipole and work function reduction tend to increase from S-donors to O-donor.

First-principles study of NaTiO with trigonal bipyramid structures: an insight into sodium-ion battery anode applications.

Developing efficient anode materials with low electrode voltage, high specific capacity and superior rate capability is urgently required on the road to commercially viable sodium-ion batteries (SIBs). Aiming at finding a new SIB anode material, we investigate the electrochemical properties of NaxTiO2 compounds with unprecedented penta-oxygen-coordinated trigonal bipyramid (TB) structures by using first-principles calculations. Identifying the four different TB phases, we perform the optimization of their crystal structures and calculate their energetics such as sodium binding energy, formation energy, electrode potential and activation energy for Na ion migration.

First-Principles Study on Structural, Electronic, and Optical Properties of Inorganic Ge-Based Halide Perovskites.

Using density functional theory calculations, we explore the structural, electronic, and optical properties of the inorganic Ge-based halide perovskites AGeX (A = Cs, Rb; X = I, Br, Cl) that can possibly be used as light absorbers. We calculate the lattice parameters of the rhombohedral unit cell with an R3 m space group, frequency-dependent dielectric constants, photoabsorption coefficients, effective masses of charge carriers, exciton binding energies, and electronic band structures by use of PBEsol and HSE06 functionals with and without SOC effect. We also predict the absolute electronic energy levels with respect to the external vacuum level by using the (001) surfaces with AX and GeX terminations, demonstrating their strong dependence on the surface terminations.

Critical Role of Water in Defect Aggregation and Chemical Degradation of Perovskite Solar Cells.

The chemical stability of methylammonium lead iodide (MAPbI) under humid conditions remains the primary challenge facing halide perovskite solar cells. We investigate defect processes in the water-intercalated iodide perovskite (MAPbI_HO) and monohydrated phase (MAPbI·HO) within a first-principles thermodynamic framework. We consider the formation energies of isolated and aggregated vacancy defects with different charge states under I-rich and I-poor conditions.

Ab initio thermodynamic study of the SnO(110) surface in an O and NO environment: a fundamental understanding of the gas sensing mechanism for NO and NO.

For the purpose of elucidating the gas sensing mechanism of SnO for NO and NO gases, we determine the phase diagram of the SnO(110) surface in contact with an O and NO gas environment by means of an ab initio thermodynamic method. Firstly we build a range of surface slab models of oxygen pre-adsorbed SnO(110) surfaces using (1 × 1) and (2 × 1) surface unit cells and calculate their Gibbs free energies considering only oxygen chemical potential. The fully reduced surface containing the bridging and in-plane oxygen vacancies under oxygen-poor conditions, while the fully oxidized surface containing the bridging oxygen atom and the oxygen dimer under oxygen-rich conditions, and the stoichiometric surface in between, was proved to be most stable.

Generation of GGTA1 biallelic knockout pigs via zinc-finger nucleases and somatic cell nuclear transfer.

Genetically modified pigs are valuable models of human disease and donors of xenotransplanted organs. Conventional gene targeting in pig somatic cells is extremely inefficient. Zinc-finger nuclease (ZFN) technology has been shown to be a powerful tool for efficiently inducing mutations in the genome.

The effect of the number of transferred embryos, the interval between nuclear transfer and embryo transfer, and the transfer pattern on pig cloning efficiency.

To improve the efficiency of producing cloned pigs, we investigated the influence of the number of transferred embryos, the culturing interval between nuclear transfer (NT) and embryo transfer, and the transfer pattern (single oviduct or double oviduct) on cloning efficiency. The results demonstrated that transfer of either 150-200 or more than 200NT embryos compared to transfer of 100-150 embryos resulted in a significantly higher pregnancy rate (48 ± 16, 50 ± 16 vs. 29 ± 5%, p<0.

Acute fatty liver of pregnancy: a report of two cases.

In the past two years, two women with acute fatty liver of pregnancy have presented at this hospital. Both patients survived, but their babies died; published rates for both mother and fetus are up to 85% mortality with this condition. Both patients presented with symptoms and signs of impending hepatic failure including jaundice, elevated aminotransferases, leukocytosis, hepatic encephalopathy and disseminated intravascular coagulation during the third trimester.

Cancer of the oral cavity, pharynx/larynx and lung in North Thailand: case-control study and analysis of cigar smoke.

The unusually high relative frequency of cancer in the laryngeal region in males (18% of all histologically diagnosed cancers) and a sex ratio of unity for lung cancer in Northern Thailand were further explored in a hospital-based case-control study in Chiang Mai. This compared patients having cancers of the oral cavity (including oropharynx), larynx, hypopharynx and lung, with controls in relation to smoking and chewing habits. Statistical analysis indicated that chewing betel is strongly associated with the occurrence of oral cancer in both sexes, and with cancer of the laryngeal region in males.