Ab initio study of the giant ferroelectric distortion and pressure induced spin-state transition in BiCoO3

Using configuration-state-constrained electronic structure calculations based on the generalized gradient approximation plus Hubbard U method, we sought the origin of the giant tetragonal ferroelectric distortion in the ambient phase of the potentially multiferroic material BiCoO3 and identified the nature of the pressure induced spin-state transition. Our results show that a strong Bi-O covalency drives the giant ferroelectric distortion, which is further stabilized by an xy-type orbital ordering of the high-spin (HS) Co3+ ions. For the orthorhombic phase under 5.8 GPa, we find that a mixed HS and low-spin (LS) state is more stable than both LS and intermediate-spin (IS) states, and that the former well accounts for the available experimental results. Thus, we identify that the pressure induced spin-state transition is via a mixed HS+LS state, and we predict that the HS-to-LS transition would be complete upon a large volume decrease of about 20%.Comment: 6 pages, 6 figures, 2 table

Soil water distribution on different number of growing years of alfalfa pasture in the Loess Plateau of Northwest China

The alfalfa pastureland in the semiarid Loess Plateau region of Northwest China usually has dry soil layers. We studied the soil water variations on alfalfa (Medicago sativa L.) grassland with different number of growing years. Seven growing years of alfalfa grassland were chosen in this study: (1) 4-year-old, (2) 6-year-old, (3) 8-year-old, (4) 12-year-old, (5) 14-year-old, (6)18-year-old and (7) 26-year-old. The results showed that the highest soil water content, 12.0 -17.15%, with different number of growing years of alfalfa grassland occurred in 80 -100 cm soil layer, but gradually became stable below 300 cm soil layer. The soil water content with 4, 6 and 8 year alfalfa grassland was in the range of 13.66 - 14.76%, with 12 and 14 year ranged within 11.76 -1 1.87% and with 18 and 26 year within 10.5%. We also found that in 0 - 1000 cm soil layer, the soil water content with different number of growing years of alfalfa grassland had differences due to different soil water conditions and water-supplying capability. The soil water content with 4 and 6 year were 13.85 and 14.22%, respectively, with 8, 12 and 14 year were 12.98, 11.25 and 11.22%, respectively, and with 18 and 26 year were 10.27 and 10.76%, respectively. After alfalfa grew for >18 years, the annual recovery of its soil water at 0 - 200 cm soil depth was 1.49%, whereas the soil water with 18 and 26 year alfalfa pastureland at 200 - 1000 cm soil depth was only 10.10%, dry soil layers occurring in alfalfa pasture. The dry soil layer of alfalfa grassland appears at 160 - 600 cm soil depth in the Loess Plateau. We found that at 250 - 350 cm soil depth, the soil water content with 4 and 6 year alfalfa grassland was in the range of 10.23 - 10.48%, presenting slightly dry soil layer and for more than 8 year, alfalfa was in the range of 7.78 - 8.48%, presenting moderately dry soil layer. In summary, the soil water use of alfalfa would grow with the number of growing years and the depth of desiccated layers will become intensified and thicker.Keywords: Alfalfa grassland, different number of growing years, soil water content, dry soil layers, Loess Plateau of ChinaAfrican Journal of Biotechnology Vol. 9(35), pp. 5686-5693, 30 August, 201

Rare case of magnetic Ag3+^{3+} ion: double perovskite Cs2_{2}KAgF6_{6}

Normally $4d$ or $5d$ transition metals are in a low-spin state. Here using first-principles calculations, we report on a rare case of a high-spin $S$=1 magnetic state for the Ag$^{3+}$ ion in the double perovskite Cs$_{2}$KAgF$_{6}$. We also explored a possibility of a conventional low-spin $S$=0 ground state and find an associated tetragonal distortion to be 0.29 {\AA}. However, the lattice elastic energy cost and the Hund exchange loss exceed the e$_{g}$ crystal-field energy gain, thus making the low-spin tetragonal structure less favorable than the high-spin cubic structure. We conclude that the compact perovskite structure of Cs$_{2}$KAgF$_{6}$ is an important factor in stabilizing the unusual high-spin ground state of Ag$^{3+}$.Comment: 6 pages, 6 figures, accepted for publication in PR

Multiobjective optimization of the production process for ground granulated blast furnace slags

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The production process of ground granulated blast furnace slag (GGBS) aims to produce products of the best grade and the highest yields. However, grade and yields are two competing objectives which can not be optimized at the same time by one single solution. Meanwhile, the production process is a multivariable strong coupling complicated nonlinear system. It is hard to establish the accurate mechanism model of this system. Considering above problems, we formulate the GGBS production process as an multiobjective optimization problem, introduce a least square support vector machine method based on particle swarm optimization to build the data-based system model and solve the corresponding multiobjective optimization problem by several multiobjective optimization evolutionary algorithms. Simulation example is presented to illustrate the performance of the presented multiobjective optimization scheme in GGBS production process

Use of the Nanobridge system for the Rapid Production of Pluipotent Stem Cells and Neural Progenitor Cells

The novel Nanobridge system allows the formation of cellular aggregates of pluripotent stem cells, which can then be grown in suspensions cultures allowing accurate control of the environment in which the cells are growing. The Nanobridge system utilizes a thermo-responsive poly N-isopropyl acrylamide (PNIPAM) polymer decorated with extracellular matrix (ECM) protein fragments (fibronectin or vitronectin) to bind to and bridge between adjacent cells and form cell aggregates at 370 C. A temperature shift from 370 C to 320 C causes the PNIPAM to become water soluble weakening the bonding between adjacent PNIPAM chains and allowing the aggregates to be broken down to smaller aggregates by increased shear forces. By returning the temperature to 370 C and increasing the culture volume with additional medium, the increased number of smaller aggregates are able to grow to a larger diameter. Repeating this cycle allows for the rapid expansion in cell numbers. In addition, the ability to vary the concentrations and ratios of the two components in the Nanobridge system, when coupled with the temperature shift procedure during passaging, allows for tight control over the aggregate diameters at all stages of the expansion process. In this paper, two examples of using the Nanobridge system to culture stem cells will be described: firstly using the system for the rapid expansion of human embryonic stem cells whilst maintaining high viability and pluripotency, and secondly; using the system to develop a process to form neural cell aggregates and maintain and expand cells at a stem/progenitor (NPC) stage, obviating the need for the current cumbersome manual methods to produce larger numbers of NPCs. In the first example, embryonic stem cells (hESC) WA09 were cultured in spinner flasks with the Nanobridge system. At the end of the growth phase, aggregates of 348 micron average diameter were reduced to an average diameter of 139microns after sub-passaging. When this cycle was repeated five times, there was a 500 fold increase in the number of cells produced, with a viability at the end of the process of 90% while maintaining key pluripotent markers NANOG, OCT3/4, SOX2, and DNMT3B. Characterization of the hESC aggregates was performed using the IN Cell Analyser 2200, which demonstrated that there was uniform cell viability and pluripotency marker distribution throughout the aggregates, ie there was no evidence of any diffusional limitations or necrotic regions within the aggregates. At the end of the expansion process it was shown that the cells were able to differentiate into all three germ layers, and that the cells could be converted, to cells types such as cardiomyocytes. The results demonstrate that the Nanobridge system is a simple and scalable method of producing large numbers of PSCs without the need for enzymes during passaging. For the production of the neural progenitors (NPCs), hESC (WA09) cells were formed and cultured as Nanobridge aggregates with diameters of 200-300 mm. Differentiation was initiated by culturing the aggregates in mTESR medium with 5uM SB431542 and 100 nM LDN for 5 days. At day 5, the medium was changed to neural basal medium (NBM) supplemented with EGF and FGF2 for the next 5 days of culture. Cultures were maintained in NBM from day 10 onwards. Passaging was performed at day 5 and day 10 and thereafter on a weekly basis for 4 weeks. Temperature shift and mechanical shear were utilized to breakup aggregates and Nanobridge components and medium were replaced during passaging. Cells demonstrated upregulation and subsequent maintenance of neural-associated markers (PAX6, SOX1, and NCAM) in aggregate culture. Passaging resulted in an overall seven fold increase in the number of cells expressing the neural-associated markers. Furthermore, neural progenitor cell aggregates exhibited the capacity to differentiate towards a more mature phenotype as demonstrated by the outgrowth of neurites. This demonstrated that the Nanobridge system has the potential to facilitate the scale-up of NPC production in bioreactors for applications in regenerative medicine and pharmacological testing

4-[(9-Ethyl-9H-carbazol-3-yl)imino­meth­yl]phenol

In the title compound, C21H18N2O, the dihedral angle between the phenol ring and the carbazole system is 39.34 (2)°. Inter­molecular O—H⋯N hydrogen bonds and C—H⋯π and π–π inter­actions [centroid–centroid distances = 3.426 (2) and 3.768 (2) Å] stabilize the crystal structure

Protective effect of human serum amyloid P on CCl4-induced acute liver injury in mice.

Human serum amyloid P (hSAP), a member of the pentraxin family, inhibits the activation of fibrocytes in culture and inhibits experimental renal, lung, skin and cardiac fibrosis. As hepatic inflammation is one of the causes of liver fibrosis, in the present study, we investigated the hepatoprotective effects of hSAP against carbon tetrachloride (CCl4)-induced liver injury. Our data indicated that hSAP attenuated hepatic histopathological abnormalities and significantly decreased inflammatory cell infiltration and pro-inflammatory factor expression. Moreover, CCl4-induced apoptosis in the mouse liver was inhibited by hSAP, as measured by terminal-deoxynucleotidyl transferase mediated nick-end labeling (TUNEL) assay and cleaved caspase-3 expression. hSAP significantly restored the expression of B cell lymphoma/leukemia (Bcl)-2 and suppressed the expression of Bcl-2-associated X protein (Bax) in vivo. The number of hepatocytes in early apoptosis stained with Annexin V was significantly reduced by 28-30% in the hSAP treatment group compared with the CCl4 group, and the expression of Bcl-2 was increased, whereas the expression of Bax and cleaved caspase-3 were significantly inhibited in the hSAP pre-treatment group compared with the CCl4 group. hSAP administration also inhibited the migration and activation of hepatic stellate cells (HSCs) in CCl4-injured liver and suppressed the activation of isolated primary HSCs induced by transforming growth factor (TGF)-β1 in vitro. Collectively, these findings suggest that hSAP exerts a protective effect againts CCl4-induced hepatic injury by suppressing the inflammatory response and hepatocyte apoptosis, potentially by inhibiting HSC activation