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  • Author: Dongmei Li x
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Abstract

This study analyzed the role of PERFORM 3D in the preliminary evaluation of seismic performance of engineering structures. Firstly, PERFORM 3D was briefly introduced, and its material constitutive model and basic model were analyzed. Then, taking a high-rise building project in Yulin, Shaanxi, China, as an example, PERFORM 3D was used to evaluate its seismic performance. After establishing the engineering model, five seismic waves were selected for simulation. The results showed that the maximum values of X-axis inter-story displacement angle and Y-axis displacement angle were 1/500 and 1/360 respectively, which were far less than the standard limit; the overall energy dissipation was good, the damping was small, the overall deformation was good, and the seismic performance was also good. In conclusion, PERFORM 3D has a good performance in the preliminary evaluation of seismic performance of engineering, and it is worth further promotion and application.

Abstract

The trophic relations of the red-crowned crane in Zhalong wetland, northeastern China may significantly be altered due to the rapid decrease in accessible food resources. To confirm this hypothesis, we determined the trophic status of this vulnerable species by using stable isotope (carbon (δ 13 C) and nitrogen (δ 15 N) methods. The δ 13 C and 15 N signatures in the red-crowned crane species were in the range of – 17.8‰ to – 18.5‰ and 6.9‰ to 8.1‰, respectively. The majority of the ecosystem of Zhalong wetland has an average food-chain length of 3.9, and the trophic level of the examined species, i.e., red-crowned crane, was approximately 3.1. The trophic relations of red-crowned cranes have changed over the period of 2004 to 2014, as the biological species in the bottom trophic level significantly exhausted in the past years. The conflict of food demand by red-crowned cranes versus the livelihood demand of local wetland residents should be resolved to ensure sustainability of food supply sustainable for rare and extinguishable species.

Pogostemon cablin (Blanco) Benth. is an important medicinal plant in Traditional Chinese Medicine (TCM). Because of differences in the chemical composition, this species has been classified into two major chemotypes, i. e. the patchouliol-type and the pogostone-type; however, no quick and effective method is presently available for the precise identification of these two chemotypes. DNA barcoding, using a standardized DNA fragment, is a promising molecular diagnostic method for species identification. We have established a reliable and quick method for the identification of the P. cablin chemotypes. Of five potential barcodes [rbcL, psbA-trnH, rpoB, ITS (internal transcibed spacer), and ndhJ], tested among 103 samples, ITS was the best candidate, as comparative studies between patchouliol-type and pogostone-type P. cablin revealed that ITS had more variable regions among these five barcodes. We suggest that ITS can serve as the most suitable barcode for differentiating between the chemotypes of P. cablin

Abstract

C24H25N3O3, monoclinic, (no. 14), a = 10.2246(7) Å, b = 21.2529(7) Å, c = 10.6924(6) Å, β = 116.990(8)°, V = 2070.4(2) Å3, Z = 4, R gt (F) = 0.0499, wR ref (F 2 ) = 0.1155, T = 102 K.

Abstract

C14H13Cl2N3Zn, M = 359.54, orthorhombic, Pna21 (No. 33), a = 10.1222(5) Å, b = 18.6435(10) Å, c = 7.6190(4) Å, V = 1437.81(12) Å3, Z = 4, R gt (F) = 0.0407, wR ref (F 2 ) = 0.0780, T = 102 K.

Abstract

C14H30Co2N2O20, triclinic, P1̄ (no. 2), a = 7.264(2) Å, b = 8.647(3) Å, c = 11.460(3) Å, α = 70.204(5)°, β = 85.143(5)°, 3 = 70.168(5)°,V = 636.7 Å3, Z = 1, Rgt(F) = 0.0274, wRref(F2) = 0.0773, T = 293 K.

Abstract

Mesenchymal stem cells (MSCs) constitute an interesting cellular source to promote brain regeneration after Parkinson’s disease. MSCs have significant advantages over other stem cell types, and greater potential for immediate clinical application. The aim of this study was to investigate whether MSCs from the human placenta could be induced to differentiate into dopaminergic cells. MSCs from the human placenta were isolated by digestion and density gradient fractionation, and their cell surface glycoproteins were analyzed by flow cytometry. These MSCs were cultured under conditions promoting differetiation into adipocytes and osteoblasts. Using a cocktail that includes basic fibroblast growth factor (bFGF), all trans retinoic acid (RA), ascorbic acid (AA) and 3-isobutyl-1-methylxanthine (IBMX), the MSCs were induced in vitro to become dopamine (DA) neurons. Then, the expression of the mRNA for the Nestin and tyrosine hydroxylase (TH) genes was assayed via RT-PCR. The expression of the Nestin, dopamine transporter (DAT), neuronal nuclear protein (NeuN) and TH proteins was determined via immunofluorescence. The synthesized and secreted DA was determined via ELISA. We found that MSCs from the human placenta exhibited a fibroblastoid morphology. Flow cytometric analyses showed that the MSCs were positive for CD44 and CD29, and negative for CD34, CD45, CD106 and HLA-DR. Moreover, they could be induced into adipocytes and osteocytes. When the MSCs were induced with bFGF, RA, AA and IBMX, they showed a change in morphology to that of neuronal-like cells. The induced cells expressed Nestin and TH mRNA, and the Nestin, DAT, NeuN and TH proteins, and synthesized and secreted DA. Our results suggest that MSCs from the human placenta have the ability to differentiate into dopaminergic cells.

Abstract

Cancer cells are relatively resistant to endoplasmic reticulum (ER) stress-induced apoptosis. However, the underlying mechanisms remain largely unclear. We observed that the microRNAs miR-221/222 are associated with apoptosis regulation under ER stress in human hepatocellular carcinoma (HCC) cells. Induction of ER stress does not trigger significant apoptosis but obviously causes downregulation of miR-221/222 in HCC cells. In these cells, ER stress-induced apoptosis is enhanced by miR-221/222 mimics and attenuated by miR-221/222 inhibitors. miR-221/222 promoted-apoptosis under ER stress is associated with p27Kip1- and MEK/ERK-mediated cell cycle regulation. Our results suggest that suppression of miR-221/222 plays a crucial role in the protection against apoptosis induced by ER stress in HCC cells.

Abstract

Transport and deposition of copper in the Earth’s crust are mainly controlled by the solubility of Cu-bearing phases and the speciation of Cu in magmatic-hydrothermal fluids. To improve our understanding of copper mobilization by hydrothermal fluids, we conducted an experimental study on the interaction between Cu-bearing phases (metallic copper, Cu2O, CuCl) and aqueous chloride solutions (H2O ± NaCl ± HCl; with Cl concentrations of 0 to 4.3 mol kg-1). The experiments were run in rapid heat/rapid quench cold-seal pressure vessels at 800 °C, 200 MPa, and logfO2 ~ NNO+2.3. Either Cu or Au capsules were used as containers. The reaction products were sampled in situ by the entrapment of synthetic fluid inclusions in quartz. Fluid composition was subsequently determined by analyzing individual fluid inclusions using a freezing cell and laser ablation inductively coupled plasma-mass spectrometry. Our results show that large isolated and isometric inclusions, free of late-stage modifications, can be preserved after the experiment even when using a high cooling rate of 25 K s-1.

The obtained results demonstrate that: (1) reaction between native Cu, NaCl solution, and quartz (± silica gel) leads to the coexistence of fluid inclusions and Na-bearing silicate melt inclusions. Micrometer- to submicrometer-sized cuprite (Cu2O) crystals have been observed in both types of the inclusions, and they are formed most probably due to the dissociation of CuOH. (2) When Cu0 reacts with HCl and CuCl solutions, or Cu+ reacts with NaCl solution, nantokite (CuCl) formed due to oversaturation has been found in fluid inclusion. Copper concentration in the fluid shows a strong positive dependence on the initial chlorine content, with Cu/Cl molal ratios varying from 1:9 to 1:1 in case 1 and case 2, respectively. When Cl is fixed to 1.5 m, initial fluid acidity has a major control on the Cu content, i.e., 0.17 ± 0.09 and 1.29 ± 0.57 m Cu were measured in fluids of case 1 and case 2, respectively. Cu solubility in pure water and in 1.5 m NaCl solutions are 0.004 ± 0.002 and 0.16 ± 0.07 m, respectively. The main responsible Cu-bearing complexes are CuOH(H2O)x in water, NaCuCl2 in NaCl solutions and HCuCl2 in alkali-free solutions. These results provide quantitative constraints on the mobility of Cu in hydrothermal solutions and confirm that Cl is a very important ligand responsible for Cu transport. The first observation that silicate melt can be generated in the fluid-dominated and native-copper-bearing system implies that transitional thermosilicate liquids can coexist with metal-rich fluids and may enhance Cu mobility in magmatic-hydrothermal systems. This may have important implications for the formation of Cu deposits in the systems with low S activities.