Asymmetric epoxidation of <Emphasis Type=Italic>α</Emphasis>,<Emphasis Type=Italic>β</Emphasis>-unsaturated ketones using <Emphasis Type=Italic>α</Emphasis>,<Emphasis Type=Italic>α</Emphasis>-diarylprolinols as catalysts

Asymmetric epoxidation of α,β-unsaturated ketones has been extensively studied and several important procedures have been developed in the last decade. This review addresses the most significant advances in asymmetric epoxidation of α,β-unsaturated ketones using proline-derived α,α-diarylprolinols as catalysts. Special attention has been paid to the enantioselective epoxidation of chalcones, α,β-unsaturated trifluoromethyl, trichloromethyl ketones and β,γ-unsaturated α-keto esters based on the reseach of our group.     

Synthesis,characterization and photoluminescence of aluminum <Emphasis Type=Italic>N</Emphasis>-aryloxo functionalized <Emphasis Type=Italic>β</Emphasis>-ketoiminate complexes

The synthesis, characterization and luminescent properties of aluminum complexes containing a dianionic N-aryloxo functionalized β-ketoiminate ligand are presented. 4-(2-Hydroxy-5-R-phenyl)imino-2-pentanone (R = Me, L¹H₂; R = tert-butyl, L²H₂) ligands reacted with AlEt₃ in tetrahydrofuran to give the aluminum complexes (L¹AlEt)₂ (1) and (L²AlEt)₂ (2) in reasonable isolated yields. X-ray diffraction revealed that complexes 1 and 2 have solvent-free centrosymmetric dimeric structures, and each aluminum center has distorted trigonal bipyramidal geometry. At room temperature, complexes 1 and 2 exhibit blue photoluminescence in acetonitrile with maximum emission wavelengths of 419 and 413 nm, respectively.     

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.     

Asymmetric intramolecular oxa-Michael addition of activated <Emphasis Type=Italic>α,β</Emphasis>-unsaturated ketones by chiral <Emphasis Type=Italic>N</Emphasis>-triflyl phosphoramide

Asymmetric intramolecular oxa-Michael addition of activated α,β-unsaturated ketones by chiral N-triflyl phosphoramide was realized. The flavanone products can be synthesized with excellent yields (50%–95%) and up to 74% ee.     

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.     

Genetic analysis of “all-fish” growth hormone gene trans ferred carp (Cyprinus carpio L.) and its F1 generation

Recombinant “all-fish” growth hormone gene (GH) was microinjected into the fertilized eggs of carp. A comparison between the growth traits of transgenics and non-transgenics was carried out, and the transgenic individuals with significant “fast-growing” effect were successfully gained. A comparison on the reproductivities was also given out between the transgenics and their non-transgenic siblings, and showed that the reproductive capacity of transgenics was substantially equivalent to those of the non-transgenics. On the other hand, the genetic separation and the characteristic distribution of the F₁ generation were genetically analyzed, which gave solid evidence for the hypothesis that 2–3 chromosomes are integrated with transgene. In addition, the distinct biological effects for multisite-integrated transgenes were further discussed. The present study opens a door for the breeding of “fast-growing” transgenic fish.     

<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.     

A new compressibility modification <Emphasis Type=Italic>k</Emphasis>-ε turbulence model with shock unsteadiness effect

A new compressibility modification k-ε model, including shock unsteadiness effect and the previous compressibility modification of pressure dilatation and dilatational dissipation rate, was developed with a simple formulation for numerical simulation in supersonic complex turbulent flows. The shock unsteadiness effect was modeled by inhibiting turbulent kinetic energy production in the governing equations of turbulent kinetic energy and the turbulent kinetic energy dissipation rate. Sarkar＇s correction models were employed accounting for the dilatational compressibility effects in the new model. Two types of flows, the free supersonic mixing layers and complex supersonic flow with transverse injection were simulated with different flow conditions. Comparisons with experimental data of the free supersonic mixing layers showed that the new compressibility modification k-ε model significantly inhibited the excessive growth of turbulent kinetic energy and improved predictions. On the supersonic mixing layer flows, prediction results with the new model were in close agreement with experimental data, accurately predicting the decreasing trend of the mixing layer spreading rate with the increase of the convective Mach number. Due to the complicated flow field with flow separation, shock unsteadi- ness modification inhibited excessive growth of the turbulent kinetic energy in shock regions and wider shock regions are predicted, thereby significantly improving results of the flow with a strong separation forecast. The flow separation was stronger, which was the primary modification effect of the new model. Predictions accord with experimental results even in strong separation flows.     

Molecular cloning of growth hormone receptor (GHR) from common carp(Cyprinus carpio L.)and identification of its two forms of mRNA transcripts

Growth hormone receptor (GHR) belongs tothehematopoietic receptor superfamily[1]. The action ofgrowth hormone (GH) in regulating growth[2],re-production[3]and i mmunity[4]has been elucidated.The binding of GHtothe GHRontarget tissues trig-gers a cascade of tyrosine and protein phosphorylationevents, which cul minates in the biological action ofGH[5 ,6]. Up to date GHR cDNAs have been clonedfrom many species[7—9],including various kinds ofmammalian ani mals ; avian of chicken and domest…     

An α-expansin, <Emphasis Type="Italic">VfEXPA1</Emphasis>, is involved in regulation of stomatal movement in <Emphasis Type="Italic">Vicia faba</Emphasis> L.

The wall loosening of guard cells differs from other types of plant cells. However, the regulation of wall loosening during stomatal movement is poorly understood. VfEXPA1 is an α-expansin gene cloned from Vicia faba epidermal strips. Expression of VfEXPA1 is regulated by darkness and submergence, and is not affected by light and abscisic acid (ABA). In situ hybridization showed that VfEXPA1 is expressed primarily in the guard cells. Overexpression of VfEXPA1 in transgenic tobacco accelerated light-induced stomatal opening, and increased both transpiration and photosynthetic rates under favorable growth conditions. Our results indicate the guard cell-expressed expansin VfEXPA1 plays an important role in regulation of stomatal opening.     

Analysis of the characteristics of the harmonics coefficient <Emphasis Type=Italic>J</Emphasis><Subscript>2</Subscript> of the Earth’s gravity field in different periods

The characteristics of the geopotential coefficient J2 in different periods are analyzed using satellite laser ranging data spanning the last 27 years.The satellites used in the analysis are Lageos1 and Lageos2.The variations in J2 are obtained by determining the dynamic orbit.The results show that there are strong seasonal and long-term variations.For different data spans,the seasonal variations agree well in terms of both amplitude and phase.Using all the data,the amplitude and phase of the annual term are 2.5 10-10 and 127°,respectively,while the amplitude and phase of the semiannual term are 0.94 10-10 and 213°,respectively.In the case of long-term variation,the secular variation in J2(J2) is-2.2 10-11 a-1 from 1984 to 2010.J2 differs for the different periods because of interannual variations,such as the 1998 anomaly.Another anomaly may have taken place during 2007-2010.Although the cause of the anomaly is unknown,it is an important observational constraint on the shape of the Earth.     

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.     

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.     

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.     

Is the maximum carbon number of long-chain <Emphasis Type=Italic>n</Emphasis>-alkanes an indicator of grassland or forest? Evidence from surface soils and modern plants

The molecular distribution of long-chain n-alkanes in 62 soil samples collected from diverse locations across eastern China was analyzed.The long-chain n-alkanes were mostly dominated by n-C29 or n-C31,regardless of the overlying vegetation type at each site.The results were compared with those summarized from the literature,covering more than 100 soil samples within China and more than 300 genera of modern plants distributed worldwide.There were similar n-alkane distribution patterns for most genera, with no clear differences among grasses,shrubs,and trees.The evidence from analyses of surface soils and modern plants indicates that the relationship between the molecular distribution of long-chain n-alkanes of surface soils and source vegetation is highly complex,and is influenced by many factors.Further,it is suggested that source vegetation types should not be simply inferred from distribution patterns of long-chain n-alkanes in sediments.     

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.     

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.     

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.     

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.     

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.