<Emphasis Type="Italic">a</Emphasis>-Wythoff’s game with <Emphasis Type="Italic">n</Emphasis> players

Letting a = 1 in a- Wythoff’s game introduced by Fraenkel yields Wythoff’s game which is a well-known 2-player impartial combinatorial game introduced by Wythoff in 1907. A method of solving n-player impartial games was presented by Krawec in 2012. In this paper, we employ Krawec’s function to analyze n > 2 players a-Wythoff’s game and obtain game values for all a 1. The results obtained cover n-player Wythoff’s game, a special case 1-Wythoff’s game.     

Overexpression of phospholipase <Emphasis Type="Italic">D</Emphasis>α gene enhances drought and salt tolerance of <Emphasis Type="Italic">Populus tomentosa</Emphasis>

The cDNA of AtPLDa （Arabidopsis thaliana Phospholipase Da） gene was introduced into P. tomentosa （Populus tomentosa） under the control of the Cauliflower mosaic virus 35S promoter. Southern and Northern blot analyses suggested that the AtPLDa gene has been transferred into the P. tomentosa genome. No obvious morphological or developmental difference was observed between the transgenic and wild-type （WT） plants. Drought and salt tolerance and gene expression of seedlings of several transgenic lines and WT plants （control） were studied. The results showed that the rhizogenesis rate and the average root-length of transgenic lines were significantly higher than WT plants after mannitol and NaCI treatment under the same growth conditions. Northern blot analysis indicated that the higher the PLDa expression in the transgenic plants, the more tolerant the transgenic plants are to drought and salt treatment. Meanwhile, another group of these transgenic lines and WT plants （control） were treated with PEG6000 and NaCI separately. The contents of chlorophylls and the activities of some anti- oxidant enzymes （superoxide dismutase, guaiacol peroxidase and catalase） as well as malondialdehyde and relative electrical conductivity were analyzed. Altogether, our results demonstrated that overexpression of the PLDa gene can enhance the drought and salt tolerance in transgenic P. tomentosa plants.     

Effect of Mg content on the structural and optical properties of Mg<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Zn<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>O alloys

Mgx Zn1–x O thin films with x = 0, 0.11, 0.28, 0.44, 0.51, and 0.65 were grown by plasma-assisted molecular beam epitaxy on (0001) sapphire substrates. X-ray diffraction measurement reveals that phase separation of the Mgx Zn1–x O films occurred at x =0.44 and 0.51. Optical absorption spectra show that the absorption edges of the films shift to high-energy side with increasing Mg contents. In resonant Raman spectra, multiple-order Raman peaks originating from ZnO-like longitudinal optical phonons were obser...     

Synthesis of <Emphasis Type="Italic">β</Emphasis>-cyclodextrin-modified carbon nanocrystals and their fluorescent behavior

Water-soluble β-cyclodextrin (β-CD)-modified carbon nanocrystals (CNCs) have been synthesized by the reaction of CNCs with mono(6-diethylenetriamino-6-deoxy)-β-CD (DETA-β-CD) and comprehensively characterized by 1H NMR, FT-IR, transmission electron microscopy (TEM) and UV-Vis. DETA-β-CD-modified CNCs (DETA-β-CD-CNCs) are luminescent, and the quantum yield is 8.41%. The photoinduced electron transfer (PET) process between DETA-β-CD-CNCs and (ferrocenylmethyl) trime-thylammonium iodide (Fc⁺) was investigated by means of fluorescence spectroscopy.     

The inhibiting effect of 1·4 recombinant P chromosome of wheat-<Emphasis Type="Italic">Agropyron cristatum</Emphasis> addition line on the <Emphasis Type="Italic">Ph</Emphasis> gene

P chromosomes may carry a genetic system that inhibits the Ph gene in wheat. Abnormal chromosome synapsis in wheat-Agropyron cristatum addition line II-21-2 (additional 1·4 recombinant P chromosome) was observed in this study. The results of cytogenetics and Ph1 gene amplification showed that the Ph1 gene was normal and the average number of quadrivalents or hexavalents was determined to be 0.41 and 0.13, respectively, in pollen-mother cells of wheat-Agropyron cristatum addition line II-21-2. The analysis o...     

Crystal structure and negative thermal expansion of solid solution Lu<Subscript>2</Subscript>W<Subscript>3−<Emphasis Type="Italic">x</Emphasis></Subscript>Mo<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>O<Subscript>12</Subscript>

A new series of solid solutions Lu₂W_3−x Mo _x O₁₂ (0.5≤x≤2.5) were successfully synthesized by the solid-state method. Their crystal structure and negative thermal expansion properties were studied using high-temperature X-ray powder diffraction and the Rietveld method. All samples of rare-earth tungstates and molybdates are found to crystallize in the same orthorhombic structure with space group Pnca and show the negative thermal expansion phenomena related to transverse vibration of bridging oxygen atoms in the structure. Thermal expansion coefficients (TEC) of Lu₂W_3−x Mo _x O₁₂ are determined as −20.0×10⁻⁶ K⁻¹ for x=0.5 and −16.1×10⁻⁶ K⁻¹ for x=2.5 but -18.6×10⁻⁶ and −16.9×10⁻⁶ K⁻¹ for unsubstituted Lu₂W₃O₁₂ and Lu₂Mo₃O₁₂ in the identical temperature range of 200 to 800°C. High-temperature X-ray diffraction (XRD) data and bond length analysis suggest that the difference between W-O and Mo-O bond is responsible for the change of TECs after the element substitution in this series of solid solutions.     

Preparation and thermal stability of Pd<Subscript>40.5</Subscript>Ni<Subscript>40.5</Subscript>Si<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>P<Subscript>19−<Emphasis Type="Italic">x</Emphasis></Subscript> bulk metallic glasses

With the addition of Si to replace some P, Pd_40.5Ni_40.5Si _x P_19−x (x=0, 2.5, 5, 9.5, 14, and 19 in atomic number fraction) bulk glassy samples with the diameter of about 5 mm were successfully prepared by use of flux treatment and water quenching technology. With the increase of Si content, the glass forming ability of Pd_40.5Ni_40.5Si _x P_19−x increases first for low Si content and then decreases for high Si content (Si≥9.5at%). The Pd_40.5Ni_40.5Si ₅ P₁₄ glassy alloy possesses the largest supercooled liquid region ΔT of 119 K, the largest reduced glass transition temperature of 0.621, and the largest γ parameter of 0.460, indicating that this glassy alloy possesses very large glass forming ability and very high thermal stability.     

First principles studies on the electronics structures of (Li<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Me<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>)FePO<Subscript>4</Subscript> (Me=Na and Be)

Based on density functional theory (DFT) of the first-principle for cathode materials of lithium ion battery, the electronic structures of (Li_1?x Me _x )FePO₄ (Me=Na and Be, x=0–0.40) are calculated by plane wave pseudo-potential method using Cambridge serial total energy package (CASTEP) program. The calculated results show that Li-site doping can improve the electronic conductivity enormously. Doping with Na has a noticeable effect on improving its electrical conductivity. However, serious structural distortion will occur when its doping density is beyond 0.25. In view of this, the best density of doping Na is less than 0.25. Doping with Be has an inconspicuous effect on increasing its electrical conductivity and has good cyclical stability, but it cannot achieve as good results as when it is doped with Na. Therefore we cannot find a middle ground between the two proposals. Considering cost and environmental protection, it is ideal to choose Na. So this method gives a reasonable prediction to the improvement of electronic conductivity through Li-site doping in LiFePO₄ material.     

Distribution of <Emphasis Type="Italic">δ</Emphasis><Superscript>18</Superscript>O in surface snow along a transect from Zhongshan Station to Dome A,East Antarctica

Surface snow samples were collected during the 14th (1997/1998) and 24th (2007/2008) Chinese National Antarctica Research Expeditions along a transect from Zhongshan Station to Dome A. The stable oxygen isotope ratios of these samples were measured to investigate their relationships with temperature and geographical parameters (latitude, longitude, altitude and distance to the coast). The results reveal a strong positive correlation (R=0.945) between δ¹⁸O and mean annual temperature, with a gradient of 0.84‰°C ^–1, which is a little higher than that in Terre Adelie Land. Regression analyses also show that the δ¹⁸O of surface snow is strongly correlated with distance to the coast (R=0.942), latitude (R=0.942), and altitude (R=0.941). But no significant correlation was found between δ¹⁸O and longitude in study area. Altitude should be the most important factor influencing the δ¹⁸O distribution because of distinctive topography. The δ¹⁸O-altitude and T-altitude gradients along this transect are determined to be –1.1‰/100 m and 1.31°C/100 m, respectively.     

Diastereoselective addition of lithium enolate of γ-substituted α-diazoacetoacetate to <Emphasis Type="Italic">N</Emphasis>-sulfinyl imines

Highly diastereoselective addition of lithium enolate of γ-substituted α-diazoacetoacetate to chiral N-sulfinyl imines has been developed. The addition products were further subjected to photo-induced Wolff rearrangement or Rh(II)-catalyzed intramolecular N–H insertion to afford chiral 4,5-disubstituted 2-oxo and 3-oxo pyrrolidines, respectively.     

Structural dependences of the <Emphasis Type="Italic">η</Emphasis><Superscript>6</Superscript> complexes of 3-amino-9-ethylcarbazole with chromium tricarbonyl fragment on third-order optical nonlinearities

Degenerate four-wave mixing measurements, using the 35 ps pulses at 532 nm, have been employed to investigate the third-order nonlinear optical parameters of two chromium tricarbonyl complexes η6-bonded to 3-amino-9-ethylcarbazole at either the NH2-substituted aryl ring （1） or the unsubstituted ring （2） and their precursor 3-amino-9-ethylcarbazole （AECz）. The second-order hyperpolarizability y of the compounds 1 and 2 were found to be 42.9×10^-31 and 35.9×10^-31 esu, respectively, approximately one order of magnitude greater than AECz. The relation between the molecular structure and second-order hyperpolarizability of the compounds I and 2 was explored in detail based on the three-level model and the density functional theory （DFT） calculation. The theoretical results indicate that the spatial distribution of electron density has the profound role in the third-order nonlinear optical properties.     

Fatty-acids and their <Emphasis Type="Italic">δ</Emphasis><Superscript>13</Superscript>C characteristics of seep carbonates from the northern continental slope of Gulf of Mexico

Here we reported the fatty-acids and their δ¹³C values in seep carbonates collected from Green Canyon lease block 185 (GC 185; Sample GC-F) at upper continental slope (water depth: ~540 m), and Alaminos Canyon lease block 645 (GC 645; Sample AC-E) at lower continental slope (water depth: ~2200 m) of the Gulf of Mexico. More than thirty kinds of fatty acids were detected in both samples. These fatty acids are maximized at C₁₆. There is a clear even-over-odd carbon number predominance in carbon number range. The fatty acids are mainly composed of n-fatty acids, iso-/anteiso-fatty acids and terminally branched odd-numbered fatty acids (iso/anteiso). The low δ¹³C values (−39.99‰ to −32.36‰) of n-C₁₂:0, n-C₁₃:0, i-C₁₄:0 and n-C₁₄:0 suggest that they may relate to the chemosynthetic communities at seep sites. The unsaturated fatty acids n-C_18:2 and C_18:1△⁹ have the same δ¹³C values, they may originate from the Beggiatoa/Thioploca. Unlike other fatty acids, the terminally branched fatty acids (iso/anteiso) show lower δ¹³C values (as low as −63.95‰) suggesting a possible relationship to sulfate reducing bacteria, which is common during anaerobic oxidation of methane at seep sites.     

Catalytic removal of <Emphasis Type="Italic">tert</Emphasis>-butyldimethylsilyl (TBS) and tetrahydropyranyl (THP) groups from protected alcohols by NO<Superscript>+</Superscript>BF<Subscript>4</Subscript><Superscript>−</Superscript> in methanol

An effective, catalytic method has been developed to remove TBS and THP groups from protected alcohols. TBS and THP ethers were selectively cleaved using a catalytic amount of NO⁺BF₄^– (5 mol%) in methanol at room temperature.     

Stable carbon isotopes in the shell of <Emphasis Type="Italic">Corbicula fluminea</Emphasis> (Müller 1774): Implications for understanding environmental changes in drainage basins

Dissolved inorganic carbon (DIC) is a primary constituent of the aquatic geochemistry of terrestrial ecosystems. Changes in DIC concentration and its isotopic composition are closely associated with environmental changes in the drainage basin. Thus, a better understanding of DIC may lead to improved characterization of environmental changes. Corbicula fluminea (Müller 1774), a bivalve native to southeast Asia and a dominant invasive species in many aquatic environments around the world, has the potential to record DIC information, particularly because of its sequential skeletal deposition. Analysis of the stable carbon isotope composition (δ ¹³C) of the shell and the aquatic DIC in the Xijiang River drainage basins in southern and western China allowed us to determine that changes in δ ¹³C in the skeleton significantly correlated with those of DIC (P < 0.01, r = 0.63). These results indicate that the isotopic signature of the shell reflects that δ ¹³C of the DIC in ambient water. The temporal resolution was at the seasonal scale. Metabolic effect does not change the co-variation, even though it makes the shell δ ¹³C 1.4‰ lower statistically than that of DIC. δ ¹³C of DIC in creeks of some watershed areas may experience large temporal changes characterization of these changes requires high sampling resolution of the shell. This problem makes the clams in these areas less preferable for reconstruction of environmental changes. The present findings provide the basis for recovering paleoenvironmental changes and carbon cycles in a watershed through analysis of fossil shells of C. fluminea, which are common in some lacustrine and/or riverine sediment sequences.     

Analysis of components of conserved “backbone sequences” among genomes of<Emphasis Type="Italic">Shigella</Emphasis> spp. strains

Difference in the genomic compositions of prokaryotes is the basis of the diversity in their biological characters. However, besides their flora- or strain-specific genes, those floras with closer relationship in the evolution also have conserved “backbone sequences”, which reveal the marks of their origin and evolution, and these “backbone sequences” are just the basis of their elementary living abilities and common biological properties. Shigella is very closely related to E. coli in the origin and evolution, and may turn out to belong to the same genus. In this study, a microarray containing E. coli K-12 whole genome and SG01 specific ORFs is used to investigate the genomic components of four Shigella strains. The results indicate that 16%–22% K-12 ORFs sequences are not detected in the genome of Shigella strains while the genome of Shigella contains at least 2800 conserved ORFs, which compose the common “backbone sequences”. Advanced analysis indicated that the “backbone sequences” are the essential components in maintaining the normal physiological activities of intestinal bacteria. Furthermore, only 20% SGO1-specific ORFs exist in other strains simultaneously, which demonstrate the great genome heterogeneity and the genetic diversity among the strains. the first two authours made equal contribution to this work.     

Effects of foliage boron-spraying on seed yields and fatty acid composition of tree peony (<Emphasis Type="Italic">Paeonia ostii</Emphasis> ‘Feng Dan’)

The influence of the foliage boron(B)-spaying concentration on the yield and fatty acid composition of tree peony (Paeonia ostii ‘Feng Dan’) was explored in the experiment of 2014-2015. In this research, a statistically significant correlation was found between the mass concentration of foliage boron- spraying and tree peony seed yield. Maximum yield increment of tree peony seeds was obtained when the boron-spraying concentration was 4 g/L. The composition of fatty acid was analyzed by gas chromatography-mass spectrometry (GC-MS), and the main components of the fatty acid composition were quantified by internal standard method. The increase in the oil extraction rate after foliage boron-spraying nutrition of different concentration was significant and ranged between 0.04% and 11.43%. Seed oil production and oil extraction rate were also increased due to the increase of seed yields. Furthermore, foliage boron-spraying had a significant effect on the content of linolenic acid and linoleic acid in seed oil.     

A phase field study for influence of elastic energy on L1<Subscript>0</Subscript>→L1<Subscript>2</Subscript> transient ordering in Ni<Subscript>75</Subscript>Al<Subscript>17</Subscript>Zn<Subscript>8</Subscript>

The influence of the elastic energy on L1₀→L1₂ transient ordering transformation was investigated by microscopic phase field method. It is found that there are three stages experienced in atomic ordering: solute clustering+L10 short range ordering → L1₀ long range ordering → L1₂ long range ordering. Before the formation of the high ordered L1₂ phase, it has firstly taken place the transformation from matrix to L1₀ phase, and then held the L1₀→L1₂ secondary transformation. Elastic energy is proved to take little effect on the stage of short range ordering, but as the elastic energy is multiplied, it obviously shortened the course of the solute clustering, and speeded up the proceeding of the L1₀ long range ordering transition. Accordingly, the increased elastic energy also strengthens the single crystalline directionality of L1₀ phase projecting on 2D plane and makes the ordered degree of Al and Zn atoms enhanced. With the temperature elevation, Al’s and Zn’s ordered degree decreased in L10 phase.     

Modification of MgO·Al<Subscript>2</Subscript>O<Subscript>3</Subscript> spinel inclusions in Al-killed steel by Ca-treatment

The modification of MgO·Al₂O₃ spinel inclusions in Al-killed steel by Ca-treatment has been studied by industrial trials and thermodynamic calculations. In the industrial trials, samples were taken systematically during the refining process in which the molten steel was treated by calcium, and the characters of the inclusions were analyzed using scanning electron microscopy (SEM) and energy dispersive spectra (EDS). The effects of Ca-treatment were evaluated by tracking the compositions of the inclusions. The results show that the modification of MgO·Al₂O₃ spinel inclusions by Ca-treatment is effective and the transformation sequence of the inclusions during the refining is Al₂O₃→MgO·Al₂O₃→liquid complex inclusions. The modification of spinel inclusions by Ca-treatment was calculated by FactSage6.0 utilizing its free-energy minimization routines. The results of thermodynamic calculations indicate that spinel inclusions are easier to be modified than Al₂O₃ inclusions and the spinel inclusions in 30CrMo steel would transform to liquid complex inclusions when the content of dissolved Ca in the molten steel exceeds 1×10⁻⁶. Also, the results show that adding more calcium into the molten steel would lower the contents of Al₂O₃ and MgO and increase the CaO content of the inclusions, while the change in SiO₂ content is little.     

Regional Δ<Superscript>14</Superscript>C patterns and fossil fuel derived CO<Subscript>2</Subscript> distribution in the Beijing area using annual plants

The level of atmosphericΔ14C and the fossil fuel derived CO 2 concentration in the Beijing area from May to September,2009, were systematically analyzed based on radiocarbon(14C)measurements of annual plants by accelerator mass spectrometry(AMS). The results show that the maximumΔ14C in Beijing was 29.6‰±2.2‰,and the minimum was–28.2‰±2.5‰,with a trend of decreasingΔ14C from the outer suburbs to inner suburbs to the urban center.This trend correlates well with increases in fossil fuel derived CO2 caused by human activities such as population density,industrial emissions and traffic,with lower values of atmosphericΔ14C associated with more intensive human activities.The fossil fuel derived CO 2 concentrations from May to September, 2009,ranged from 3.9±1.0 ppm to 25.4±1.0 ppm.It was calculated that each additional 1 ppm of CO2 from fossil fuels depleted the atmosphericΔ14C by approximately 2.70‰.This study suggests that 14C measurements of annual plants by AMS provide an effective method to rapidly trace fossil fuel derived CO2.