Study on the Rheological Properties and Constitutive Model of Shenzhen Mucky Soft Soil

In order to obtain the basic parameters of numerical analysis about the time-space effect of the deformation occurring in Shenzhen deep soft-soil foundation pit, a series of triaxial consolidated-undrained shear rheology tests on the peripheral mucky soft soil of a deep foundation pit support were performed under different confining pressures. The relations between the axial strain of the soil and time, as well as between the pore-water pressure of the soil and time, were achieved, meanwhile on the basis of analyzing the rheological properties of the soil, the relevant rheological models were built. Analysis results were proved that the rheology of Shenzhen mucky soft soil was generally viscous, elastic, and plastic, and had a low yield stress between 90 and 150 kPa. The increase in pore-water pressure made the rheological time effect of the mucky soft soil more remarkable. Thus, the drainage performance in practical engineering should be improved to its maximum possibility extent to decrease the soft-soil rheological deformation. Lastly, a six-component extended Burgers model was employed to fit the test results and the parameters of the model were determined. Findings showed that the extended Burgers model could satisfactorily simulate the various rheological stages of the mucky soft soil. The constitutive model and the determination of its parameters can be served as a foundation for the time-space effect analysis on the deformation of deep soft-soil foundation pits

Structure and superconductivity of Mg(B1-xCx)2 compounds

In this paper, we reported the structural properties and superconductivity of Mg(B1-xCx)2 compounds. Powder x-ray diffraction results indicate that the samples crystallize in a hexagonal AlB2-type structure. Due to the chemical activity of Mg powders, a small amount of MgO impurity phase was detected by x-ray diffraction. The lattice parameters decrease slightly with increasing carbon content. Magnetization measurements indicate the non-stoichiometry of MgB2 has no influence on the superconducting transition temperature and the transition temperature width. The addition of carbon results in a decrease of Tc and an increase in the superconducting transition width, implying the loss of superconductivity.Comment: PDF files, 5 pages,3 figures, Accepted by Chinese Physics on Feb. 26, 2001(in press

catena-Poly[[[diaqua­iron(II)]-μ-pyridine-2,5-dicarboxyl­ato-[tetra­aqua­iron(II)]-μ-pyridine-2,5-dicarboxyl­ato] tetra­hydrate]

In the crystal structure of the title compound, {[Fe2(C7H3NO4)2(H2O)6]·4H2O}n, there are two types of coordination for the FeII atoms. One FeII atom is in a distorted octa­hedral N2O4 environment, with two chelating rings from the pyridine­dicarboxyl­ate ligands and two O atoms from the water mol­ecules, while the other is in a distorted octa­hedral O6 environment with two O atoms from the pyridine­dicarboxyl­ate ligands and four O atoms from the water mol­ecules. Both FeII atoms lie on crystallographic centers of symmetry. The complex possesses an infinite chain structure running along the [101] direction. These chains are inter­connected by the uncoordinated water mol­ecules through O—H⋯O hydrogen bonds

Bis[N-benzyl-2-(quinolin-8-yl­oxy)acetamide]dichloridocopper(II) acetonitrile solvate monohydrate

In the title complex, [CuCl2(C18H16N2O2)2]·CH3CN·H2O, the six-coordinated Cu atom is in a distorted octa­hedral geometry with the donor centers of two O atoms and two N atom from two bidentate ligands, and two chloride ions. In the crystal, pairs of inter­molecular N—H⋯ Cl hydrogen bonds form centrosymmetric dimers and inter­molecular O—H⋯ O hydrogen bonds between the ligand and the uncoordinated water mol­ecules link the dimers into chains parallel to the c axis

Structural Characteristics and Driving Factors of the Planktonic Eukaryotic Community in the Danjiangkou Reservoir, China

Planktonic eukaryotes are widespread in aquatic ecosystems, and the study of their community composition and driving factors is of great significance to protecting and maintaining the balance of these ecosystems. This study evaluates five typical ecological sites in the Danjiangkou Reservoir—the water source for the project. This was done to comprehensively understand the composition of Danjiangkou Reservoir planktonic eukaryotes, and ensure the ecological balance of the water source for the South-to-North Water Diversion Project. The diversity of the planktonic eukaryotes in surface water and the factors driving changes in their abundance are analyzed with an 18S ribosomal DNA sequencing approach. Monitoring shows that the Danjiangkou Reservoir has good water quality. The Danjiangkou Reservoir planktonic eukaryote community is mainly composed of 11 phyla, of which Cryptomonadales is dominant, accounting for an average percentage of 65.19% of the community (47.2–84.90%). LEFSe analysis shows significant differences among samples in the abundances of 13 phyla, 20 classes, 23 orders, 26 families, and 27 genera, and there are also significant differences in the diversity of planktonic eukaryotes at different temporal and spatial scales. Redundancy analysis (RDA) show that water temperature, DO, SD, TN, and Chla are significant factors that affect the composition of the planktonic eukaryote community. Spearman rank correlation analysis combined with taxonomic difference analysis shows that Kathablepharidae and Choanoflagellida are not sensitive to environmental or physicochemical factors and that the interannual variations in their abundance are not significant. Network analysis shows that Protalveolata, Basidiomycota, P1-31, Bicosoecida, and Ochrophyta represent important nodes in the single-factor network, while Chytridiomycota, P1-31, Cryptomycota, Ochrophyta, Ichthyosporea, Bicosoecida, Protalveolata, and physicochemical factors (ORP, TN, WT, DO, SD, NH3-N, and NO3-N) represent important nodes in the two-factor network

Memory of chirality in J-type aggregates of an achiral perylene dianhydride dye created in a chiral asymmetric catalytic synthesis

Perylene dyes tend to form H-aggregates because of their large aromatic p-core and high hydrophobicity. We report here a chiral asymmetric catalytic synthesis of water-soluble chiral J-aggregates from highly hydrophobic and achiral perylene dianhydride (PDA). We propose to generate in situ aggregating hydrophobic species from a water soluble precursor so that it aggregates at a low concentration in solution within a predesigned microenvironment to stabilize the formed aggregates. Choosing PDA as an example, we generated it in situ from a water-soluble perylene-3,4,9,10-tetracarboxylate in acidic cetyltrimethylammonium bromide (CTAB) micelle solution, employing small molecule D- and/or L-tartaric acid as the chiral auxiliary. CD spectra of the PDA J-aggregates formed in the presence of D-and L-tartaric acid, respectively, were mirror images of each other. When the chiral auxiliary was absent, water-soluble J-aggregates of PDA were also obtained from acidic HCl-CTAB solution but they were then achiral. This confirms that the chirality of the J-aggregates is transferred from tartaric acid. Using an L-/D-tartaric acid mixture of varying ee as the chiral auxiliary, the exciton-coupled induced circular dichroism (ICD) signal of the formed PDA J-aggregates shows an "S"-shaped profile when plotted versus ee, indicating that chiral amplification occurs. Purified J-aggregates were found to contain PDA and CTAB, whereas tartaric acid was hardly detected, yet the ICD signals remained the same as those in the presence of tartaric acid before purification. This indicates memory in the J-aggregates of the chirality of tartaric acid. The ICD signal of the purified J-aggregates was also found to remain unchanged upon addition of a large excess of the other enantiomer of tartaric acid than the one used to induce the chirality, implying the imprinting of the chirality in the J-aggregates. The J-aggregates of PDA were shown to be positively charged from the polar heads of the CTAB surfactant molecules that help to disperse the aggregates and prevent their precipitation in aqueous solution. It was found that it is critical that the surfactant tail is long enough for the chiral J-aggregates to be created. This suggests that the hydrophobic tail might act as a pillar to support the J-aggregates that are driven by edge-edge hydrophobic interactions. With this in situ generation for the highly hydrophobic perylene dyes we succeeded in creating water soluble J-aggregates, chiral and achiral, in a controllable manner.National Natural Science Foundation of China[20835005]; MOST of China[2011CB910400

Inflammation mobilizes copper metabolism to promote colon tumorigenesis via an IL-17-STEAP4-XIAP axis.

Copper levels are known to be elevated in inflamed and malignant tissues. But the mechanism underlying this selective enrichment has been elusive. In this study, we report a axis by which inflammatory cytokines, such as IL-17, drive cellular copper uptake via the induction of a metalloreductase, STEAP4. IL-17-induced elevated intracellular copper level leads to the activation of an E3-ligase, XIAP, which potentiates IL-17-induced NFκB activation and suppresses the caspase 3 activity. Importantly, this IL-17-induced STEAP4-dependent cellular copper uptake is critical for colon tumor formation in a murine model of colitis-associated tumorigenesis and STEAP4 expression correlates with IL-17 level and XIAP activation in human colon cancer. In summary, this study reveals a IL-17-STEAP4-XIAP axis through which the inflammatory response induces copper uptake, promoting colon tumorigenesis

Alternative chiral thiols for preparation of chiral CdS quantum dots covered immediately by achiral thiols

Developing of alternative chiral thiol stabilizers from the assembly of achiral thiol (e.g. thioglycolic acid) and chiral ligand (e.g. arginine) via both hydrogen bonding and electrostatic interactions was proposed and successfully applied to an efficient preparation of chiral CdS quantum dots (QDs). Chiral CdS QDs capped mainly with achiral thioglycolic acid were also obtained that may allow the chiral QDs to be modified for extended applications.MOST of China[2011CB910403]; NSF of China[20835005

Proline-Based Boronic Acid Receptors for Chiral Recognition of Glucose

Chiral recognition remains a major challenge in the area of molecular receptor design. With this research, we set out to explore the use of proline-based receptors for chiral recognition. Importantly, the proline structure allows for the introduction of at least two different binding groups due to the availability of both an amine and carboxylic acid group. Here we report a proof-of-concept exploration into the chiral recognition of d/l-glucose as a model chiral species, which prefers to bind to at least two boronic acid groups. We evaluated several proline-based receptors incorporating two phenylboronic acid groups, respectively, at the N- and C-termini of the amino acid residue, via amide bonds. We confirmed that the receptors exhibited chiral recognition using CD, 1H NMR, and 19F NMR spectroscopy. Given the derivation diversity available, our strategy to use proline-based receptors for chiral recognition holds significant promise for extension to other chiral systems. </p

Transcriptome profiling and digital gene expression by deep-sequencing in normal/regenerative tissues of planarian Dugesia japonica

AbstractPlanarians exhibit an extraordinary ability to regenerate lost body parts which is attributed to an abundance of pluripotent somatic stem cells called neoblasts. In this article, we report a transcriptome sequence of a Planaria subspecies Dugesia japonica derived by high-throughput sequencing. In addition, we researched transcriptome changes during different periods of regeneration by using a tag-based digital gene expression (DGE) system. Consequently, 11,913,548 transcriptome sequencing reads were obtained. Finally, these reads were eventually assembled into 37,218 unique unigenes. These assembled unigenes were annotated with various methods. Transcriptome changes during planarian regeneration were investigated by using a tag-based DGE system. We obtained a sequencing depth of more than 3.5million tags per sample and identified a large number of differentially expressed genes at various stages of regeneration. The results provide a fairly comprehensive molecular biology background to the research on planarian development, particularly with regard to its regeneration progress