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Single atom catalysts (SACs) based on 2D materials have been identified to be efficient in many catalytic reactions. In this work, the catalytic performance of Pd/Pt embedded planar carbon nitride (CN) for CO oxidation has been investigated via spin-polarized density functional theory calculations. We find that Pd/Pt can be firmly anchored in the porous CN monolayer due to the strong hybridization between Pd/Pt-d orbitals and adjacent N-2p orbitals. The resulting high adsorption energy and large diffusion barrier of Pd/Pt ensures the remarkable stability of the catalyst Pd/Pt@CN during the CO oxidation reaction. The three distinct CO reaction mechanisms, namely, Eley-Rideal (ER), Langmuir-Hinshelwood (LH), and tri-molecular Eley-Rideal (TER), are taken into consideration comparatively. Intriguingly, the oxidation reaction on Pd@CN prefers to proceed through the less common TER mechanism, where two CO molecules and one O2 molecule need to cross a small reaction barrier of 0.48 eV, and finally dissociate into two CO2 molecules. However, the LH mechanism is the most relevant one on Pt@CN with a rate-limiting reaction barrier of 0.68 eV. Moreover, the origin of the SAC's reactivity enhancement is the electronic "acceptance-donation" interaction caused by orbital hybridization between Pd/Pt and preadsorbed O2/CO. Our findings are expected to widen the catalytic application of carbon-based 2D materials.

Based on first-principles calculations, we study the hydrogen evolution reaction (HER) on metal-free C2N and make efforts to improve its catalytic performance. At H* coverages (θ) of 3/6 and 4/6, the free energy of hydrogen adsorption (ΔGH*) is 0.10 eV and 0.07 eV, respectively, which is competitive with the precious catalyst Pt. Moreover, ΔGH* can be modulated to zero under a tensile strain, and the strength of the strain depends on the H concentration. Experimentally, it is possible to achieve a strain of around 2% through coupling C2N with graphene, and the HER performance of the hybrids would be generally enhanced. Moreover, the catalytic activity of the hybrids is tunable via electron and hole doping of graphene. In the strong H binding cases (θ = 1/6), anchoring Mn atoms into C2N exhibits a perfect catalytic property with ΔGH* of -0.04 eV. Therefore, C2N-based catalysts are expected to be easily synthesized and highly active catalysts for the HER. These findings may shed light on replacing Pt by metal-free or/and non-precious metal counterparts.

Based on first-principles calculations, we present a systematic investigation of the electronic and magnetic properties of armchair phosphorene nanoribbons (APNRs) functionalized by 3d transition metal (TM) atoms. We found that the central hollow site is the most favorable adsorption site for Mn, Co and Ni, while Fe preferentially occupies the edge hollow site. All of the TM atoms bind to the adjacent P and their adsorption energies are in the range of -4.29 eV to -1.59 eV. Meanwhile, the large ratio of the adsorption energy to the cohesive energy of the metal bulk phase indicates that TM atoms have a preferred 2D growth mode on the edge hydrogenated armchair phosphorene nanoribbons (H-APNRs). The magnetic moments reduce by about 2-4 μB, relative to their free atom states, depending on whether the TM atom is in the high-spin or low-spin state. This reduction is mainly attributed to the electrons transferring from the high-level TM 4s shell to the low-lying 3d shell. Our results demonstrate that TM atom adsorption is a feasible approach to functionalizing the H-APNRs chemically, which results in peculiar electronic and magnetic properties for potential applications in nano-electronics and spintronics.

Hybrid structures have attracted a great deal of attention because of their excellent properties, which can open up a way we could not foresee in materials science and device physics. Here, we investigate the electrical and optical behaviors of SiC(GeC)/MoS 2 heterostructures, using first principles calculations based on density functional theory. Non-covalent bonding exists between the junctions due to the weak orbital coupling. Both junctions have optically active band gaps, smaller than that of the SiC or GeC and MoS 2 layers, which result in enhanced optical adsorption under visible-light irradiation. A small number of electrons transfer from SiC/GeC to MoS 2 causing its n-doping. Furthermore, the charge density states of the valence band maximum and the conduction band minimum are localized at different sides, and thus the electron-hole pairs are spatially separated. Our results provide a potential scheme for photovoltaic materials.

The basic premise of high yield in rice is to improve leaf photosynthetic efficiency and coordinate the source-sink relationship in rice plants. Quantitative trait loci (QTLs) related to morphological traits and chlorophyll content of rice leaves were detected at the stages of heading to maturity, and a major QTL (qLSCHL4) related to flag leaf shape and chlorophyll content was detected at both stages in recombinant inbred lines constructed using the indica rice cultivar 93-11 and the japonica rice cultivar Nipponbare. Map-based cloning and expression analysis showed that LSCHL4 is allelic to NAL1, a gene previously reported in narrow leaf mutant of rice. Overexpression lines transformed with vector carrying LSCHL4 from Nipponbare and a near-isogenic line of 93-11 (NIL-9311) had significantly increased leaf chlorophyll content, enlarged flag leaf size, and improved panicle type. The average yield of NIL-9311 was 18.70% higher than that of 93-11. These results indicate that LSCHL4 had a pleiotropic function. Exploring and pyramiding more high-yield alleles resembling LSCHL4 for super rice breeding provides an effective way to achieve new breakthroughs in raising rice yield and generate new ideas for solving the problem of global food safety., (© The Author 2014. Published by Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.)

The aim of the study was to test the efficacy of a one month in-patient naturopathy and yoga programme for patients with asthma. Retrospective data of 159 bronchial asthma patients, undergoing the naturopathy and yoga programme, was analyzed for Forced Vital Capacity, Forced Expiratory Volume at the end of 1 second, Maximum Voluntary Ventilation and Peak Expiratory Flow Rate on admission, 11th day, on discharge and once in three months for three years. The paired sample t test results showed significant increase in the Forced Vital Capacity and Forced Expiratory Volume from the date of admission up to 6th month (P < 0.0035) post Bonferroni correction. Maximum Voluntary Ventilation significantly increased from admission till the date of discharge (P < 0.0035) and Peak Expiratory Flow Rate significantly increased from admission till the 36th month of follow-up (P < 0.0035), post Bonferroni correction. This validated the beneficial effect of combining naturopathy and yoga for the management of bronchial asthma.

The growing world population and shrinkage of arable land demand yield improvement of rice, one of the most important staple crops. To elucidate the genetic basis of yield and uncover its associated loci in rice, we resequenced the core recombinant inbred lines of Liang-You-Pei-Jiu, the widely cultivated super hybrid rice, and constructed a high-resolution linkage map. We detected 43 yield-associated quantitative trait loci, of which 20 are unique. Based on the high-density physical map, the genome sequences of paternal variety 93-11 and maternal cultivar PA64s of Liang-You-Pei-Jiu were significantly improved. The large recombinant inbred line population combined with plentiful high-quality single nucleotide polymorphisms and insertions/deletions between parental genomes allowed us to fine-map two quantitative trait loci, qSN8 and qSPB1, and to identify days to heading8 and lax panicle1 as candidate genes, respectively. The quantitative trait locus qSN8 was further confirmed to be days to heading8 by a complementation test. Our study provided an ideal platform for molecular breeding by targeting and dissecting yield-associated loci in rice.