Microtremor-based analysis of the dynamic response characteristics of earth-fissured sites in the Datong basin, China

This study conducted microtremor testing along six survey lines that cross three typical earth fissures in the Datong basin to determine the dynamic response characteristics of earth fissure sites with regard to the Fourier amplitude spectrum,response spectrum,and Arias intensity.The results show the following.(1)The predominant frequency of an earth fissure site is mainly affected by the thickness and the shear wave velocity of the soil layer and is minimally effected by the presence of an earth fissure.(2)Earth fissures have a pronounced amplification effect on dynamic response.Fourier amplitude,response acceleration,and Arias intensity are high near an earth fissure and decrease with an increase in distance from the earth fissure,tending toward stability at a distance of 20 m.(3)The area that is seriously affected by this amplification is within 6-8 m of an earth fissure,and the general affected area is farther out than this,to a distance of 25 m.(4)New construction should be avoided in an area affected by the amplification,and existing buildings in general and seriously affected areas need to be reinforced to increase their seismic fortification intensity.

A New Discovery on the Deformation Behavior of Shale Gas Reservoirs Affecting Pore Morphology in the Juhugeng Coal Mining Area of Qinghai Province, Northwest China

Objective The Juhugeng mining area in Qinghai Province of northwest China has attracted wide attention among geologists for it hosts typical coal measure gases.The shale gas reservoirs were reformed by intensive structural movements during geological periods,

Effect of HuoguⅡFormula(活骨Ⅱ方) with Medicinal Guide Radix Achyranthis Bidentatae on Bone Marrow Stem Cells Directional Homing to Necrosis Area after Osteonecrosis of the Femoral Head in Rabbit

Objective： To investigate the effect of Huogu II Formula （活骨 II方 ） with medicinal guide Radix Achyranthis Bidentatae （Ach） on bone marrow stem cells （BMSCs） homing to necrosis area after osteonecrosis of the femoral head （ONFH） frozen by liquid nitrogen in rabbit as well as to explore the mechanism of prevention and treatment for ONFH. Methods： The animal model of ONFH was established by liquid nitrogen frozen on the rabbit left hind leg. Forty-eight Japanese White rabbits were randomly assigned to sham-operated group, model group, Huogu II group, and Huogu II plus Ach group, with 12 rabbits in each. During the course of ONFH animal model establishment, all rabbits were subcutaneously injected with recombinant human granulocyte colony-stimulating factor [rhG-CSF, 30 μg/（kg.day） for continuous 7 days]. Meanwhile, normal saline and decoction of the two formulae were administrated by gavage, respectively. White blood cells （WBC） were counted in peripheral blood before and after injection of rhG-CSF. Materials were drawn on the 2rid and 4th weeks after model built; bone glutamine protein （BGP） and bone morphogenetic protein 2 （BMP2） levels in serum were tested. Histopathologic changes were observed by hematoxylin and eosin （HE） staining. BMP2 mRNA levels were detected with in situ hybridization （iSH） staining. 5-Bromo-2＇-deoxyuridine （BrdU） and stromal cell derived factor 1 （SDF-1） were measured by immunohistochemical assay in femoral head of the left hind leg. Results： Compared with the shamoperated group, the ratio of empty lacuna, serum BGP, and SDF-1 level in the model group increased significantly, and BMP2 in both serum and femoral head decreased significantly. However, in comparison with the model group, the empty lacuna ratio of Huogu II group and Huogu II plus Ach group decreased obviously in addition to the levels of serum BGP and BMP2, and the expressions of BMP2 mRNA, BrdU, and SDF-1 increased significantly. Above changes were particularly obvious in Huogu II plus Ach group. BGP and SDF-1 on the 2nd week and empty lacuna rate and serum BMP2 level on the 4th week in Huogu II group significantly exceeded their counterparts. On the 2nd week, only in Huogu II plus Ach group that the BrdU counting rose significantly. On the 4th week, empty lacuna rate and serum BMP2 level in Huogu II plus Ach group exceeded those in Huogu II group distinctively. Conclusions： To a certain extent, the medicinal guide Ach improves the preventive and therapeutic effects of Huogu II Formula on expedmental ONFH model. The possible mechanism of this is related to its promoting effect on directional homing of BMSCs to the necrosis area.