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Using first-principles calculations, we investigate the stability and electronic properties of five isomers of two-dimensional (2D) GeSe monolayer under in-plane strain. Our calculated results show that the five isomers of GeSe monolayer are all stable. It is found that the α-GeSe has a direct band gap, while each of the β-GeSe, γ-GeSe, δ-GeSe and ε-GeSe possesses an indirect band gap. By applying compressive or tensile uniaxial and biaxial strain to the five GeSe isomers, the indirect-to-direct transition in band gap is found. In the α-GeSe, the changes from indirect-to-direct and semiconducting-to-metallic are both found under an applied strain. In the 2D β-GeSe and γ-GeSe, an adjustable range of indirect band gap under strain is found. Moreover, a direct band gap in the δ-GeSe is found separately under the biaxial compression strain of σxy = –2% and σxy = –4%. By applying a tensile strain of 10% along the armchair direction in ε-GeSe, a transition from an indirect to direct band gap occurs. When the tensile strain is continuously increased to 20%, the band structure of ε-GeSe maintains direct character. This direct band gap can be tuned from 1.21 eV to 1.44 eV. When 10% tensile strain is applied along the biaxial direction, the transition in band gap from indirect-to-direct also occurs. Our results indicate that the direct band gap can be tuned from 0.61 eV to 1.19 eV when the tensile strain is increased from 10% to 19% in ε-GeSe.

After more than half century development, remarkable achievements have been made in the study of earth's interior electrical structure by using the magnetotelluric (MT) method. The majority of these research results are based on the electrical isotropic assumption. However, the electrical anisotropy phenomenon is prevalent in the earth interior, and the presence of such anisotropy in the crust and upper mantle is an important link factor among geoelectric models, underground structure and tectonic models. In this paper, the tensor conductivity is first introduced by starting from the Maxwell equations, then we deduce a set of partial differential equations with respect to Ex and Hx according to the characteristic of two-dimensional electrical anisotropic structure. By using the partial differential equations, the appropriate solutions of Ex and Hx are solved, and other field components are obtained on the basis of Ex and Hx. In order to recognize the characteristics of electromagnetic propagation under common and special geological conditions, the influence on the measured MT data is studied by the forward simulation on ordinary and special two-dimension anisotropic electrical structure, which lays theoretical foundation for the subsequent processing and interpretation of MT data. Finally, the electrical anisotropy theory is introduced into processing and interpretation of MT data based on the results in the paper, and the widespread existence of electrical anisotropy is illuminated, and the exactness of this theory and practicability of the algorithm are verified by means of the two-dimension forward fitting interpretation on the MT data from Xinjiang. This work would provide theoretical basis and technical guidance for analyzing and explaining the electrical anisotropy in MT data and help opens approaches for processing of measured MT data.

Soil-bentonite (SB) vertical slurry cutoff wall is a useful treatment for urban industrial contaminated sites. Due to the clay−heavy metal interaction, significant changes would occur in the engineering behavior of SB cutoff walls. However, previous study is limited to kaolinitic soils or montmorillonitic soils along using solidum chloride and/or calcium chloride as target contaminant. In this work, a series of oedometer tests were conducted to investigate the effects of lead (Pb) on the compressibility and the permeability of kaolin-bentonite (KB) mixtures, a simplified model of in-situ SB cutoff wall backfills. In addition, sedimentation tests were conducted to interpret the mechanism controlling the change of compressibility and permeability from the perspective of soil fabric. The Pb-contaminated KB mixtures for oedometer tests and sedimentation tests were prepared with bentonite contents of 0, 5%, 10%, and 15% by dry mass, and they were mixed with pre-determined volume of lead nitrate solution based on designed Pb concentration and solid-to-solution ratio. The Pb concentration was controlled as 0, 0.1, 0.5, 1.0, 5.0, 10, and 50 mg/g with a solid-to-solution ratio of approximate 0.5. The prepared KB mixtures with bentonite contents of 0, 5%, and 10% were chosen for the sedimentation tests. They were freeze-dried and mixed with DDI with a solid-to-solution ratio of 10 g/100 mL. The results indicate that pH, compressibility, and permeability of KB mixture changed considerably with respect to Pb concentration. It is concluded that the fabric of KB mixture, depending on the particle−particle interaction subjected to different ranges of pH and Pb concentration, governs the sedimentation behavior and permeability. The results of liquid limit (wL) cannot be explained in terms of the sedimentation behavior since it is only ionic-dependent.

In order to detect the molecular mechanism of heterosis in pigs, an mRNA differential display (DD) technique was performed to investigate the differences in gene expression in the longissimus dorsi muscle tissues from Meishan, Meishan×Large White cross and Large White pigs. Fourteen expressed sequence tags (ESTs), differentially expressed between the hybrid and purebred pigs, were isolated and identified through semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Nucleotide sequence analysis revealed that the 14 ESTs are not homologous to any of the known genes or ESTs. These novel ESTs were then deposited in the GenBank database. Tissue expression profile analysis showed that the ESTs were expressed in most tissues, including heart, spleen, liver, kidney, small intestine, ovary and lung, and this also implied that these genes must be important for the life process. Our results indicate the diversity of differential display of genes between the hybrids and purebreds in the Meishan×Large White cross combination. Results also suggest that heterosis in pigs might be derived from the differential expression of many indispensable genes in specific life phases.

A phytochemical investigation of the ethanolic extracts of the dried roots of Euphorbia nematocypha resulted in the isolation of a new phenylpropanoid, 16-O-caffeoyl-16-hydroxylhexadecanoic acid (1), together with 23 known compounds (2–24). Their structures were elucidated on the basis of spectroscopic data. Compound 1 was first to be isolated as a caffeic acyl long chain alkyl acid from the family Euphorbiaceae. The new isolated phenylpropanoid showed potent cytotoxic activities against the MCF-7 and HeLa cell lines.

The molecular genetic characteristics were evaluated, and the genetic effects of marker loci on heterosis of three traits (birth weight, BWT; average daily gain, ADG; and feed and meat ratio, FMR) were analysed in the experimental pig populations: Yorkshire (Y, n=34), Landrace (L, n=46) and Meishan (M, n=55); Yorkshire×Landrace (YL, n=32) and its reciprocal (LY, n=36), Yorkshire×Meishan (YM, n=82) and its reciprocal (MY, n=47), by 39 microsatellite markers selected from pig chromosomes SSC4, 6, 7, 8 and 13. The results indicated that observed alleles ranged from 2 to 6, average 4.13, observed heterozygosity varied from 0.39 (Y) to 0.58 (YM+MY) and average polymorphism information content (PIC) varied from 0.33 (Y) to 0.5 (YM). There were two loci (sw2155 and sw1037) at which the alleles were fixed in Y and L, and there were three loci (sw2409, sw2454 and sw1691) at which the alleles were fixed in M. The results from heterozygosity and kinship analysis revealed an intrinsic genetic relationship among the seven populations. Furthermore, the results on genetic effect analysis indicate that several marker loci had a significant effect on heterosis of the three traits in the two different F1 crossbred populations (P⩽0.01), for example s0161, swr1130 and sw1856 for BWT, sw1856 and swr2036 for ADG, and sw1302 and swr2036 for FMR. The significant marker loci implied a deep genetic relationship between molecular marker loci and heterosis.

In order to reveal the molecular basis of heterosis, Large White (LW), an introduced European pig breed, and Meishan (MS), a Chinese indigenous pig breed, were selected to hybridize directly and reciprocally in the present experiment. mRNA differential display (DD) technique was performed to identify genes that were differentially expressed in the backfat tissues of hybrids (LW×MS, MS×LW) and purebred (LW×LW, MS×MS) pigs. The ten anchor primers in combination with ten arbitrary primers (100 sets in total) were used and nearly 1500 reproducible bands were observed in polyacrylamide gels. The 40 differentially displayed bands were selected for cloning and sequencing. Thirty-six out of 40 expressed sequence tags (ESTs) proved to be novel and the sequences were submitted to GenBank (accession No. CV507051-CV507087); the other four showed similarity to known genes published in GenBank. Three among 36 novel ESTs were chosen for further identification with semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). The result showed that two ESTs were differentially expressed, and the third showed no obvious difference between hybrids and purebreds. In order to reduce the percentage of false-positive DD, RNA pools of four types of pigs were constructed, by mixing samples from six pigs of the same genotype, and subjected to DD. Stringent annealing temperature was applied and only bands that could be repeated in duplicate PCR were used for further study. The results showed that the expression pattern of these 36 ESTs differed among the four genotypes of pigs, suggesting that the genes corresponding to these differentially expressed ESTs might be related to the heterosis occurring in fat tissue.

Previously candidate gene approach revealed estrogen receptor (ESR) locus was associated with increased litter size. In this study, PvuII polymorphisms of ESR gene was detected by PCR-RFLP, and ESR locus was evaluated for its association with reproductive tracts components in the Large White×Meishan (LW×M) F2 offspring. Ninety seven gilts with reproductive tracts components records and 136 offspring with performance traits records were genotyped and the results were used to estimate allele substitution effects. The results showed that two alleles (A and B) were identified, and 121 bp fragments were observed for the AA genotype and 65 bp and 56 bp fragments for the BB genotype; the length of uterine body (LUB) of BB gilts were significantly shorter than AA gilts', the additive effect was -1.762 cm; the uterine weight (UW) of AB gilts were significantly lighter than AA gilts' with the additive effect -18.058 g; no significant associations of ESR alleles with ovulation rate (OR), length of uterine horn (LUH), length of uterine cervix (LUC), weight of two ovaries (OW), volume of uterine lumen (VUL), length of oviduct (LO) were observed. BB genotypes gilts need significantly less days to 100 kg (D100 kg) than AA genotypes (p