The effects of solution and aging treatments on the microstructures and mechanical properties of tungsten inert gas arc welded AZ61 magne-sium alloy joints were investigated by microstructural observations,microhardness tests and tensile tests.The results showed that the solution treatment led to the β-Mg17Al12 particles dissolved into the α-Mg grains.Hence,the microhardness of the fusion zone and the ultimate tensile strength of the welded joints were the lowest.With the increase of the aging temperature,the volume fraction of the β-Mg17Al12 particles in the fusion zone increased and this enhanced the microhardness of the fusion zone gradually.Also,the elongation of the welded joints was in-creased slightly with the increase of the volume fraction of the β-Mg17Al12 particles.However,the ultimate tensile strength of the welded joints increased at first and dropped at 190 ?C due to cracks formed at the boundaries of the β-Mg17Al12 particles.
The causative agent of tuberculosis,Mycobacterium tuberculosis,is one of the most successful of human pathogens.It can evade the host immune response and establish a persistent infection or enter a dormant state within the host which can be reactivated if the host becomes immuno-compromised.Both of these features are major obstacles to tuberculosis eradication.Dormancy and reactivation of M.tuberculosis are tightly coordinated dynamic processes involving numerous genes and their products.Molecular mechanisms underlying M.tuberculosis persistence may provide an opportunity for the discovery of effective drug targets for tuberculosis control.Here,we review the genes required for M.tuberculosis persistence and propose a regulatory network for the action of these genes using text mining.This should provide fresh insights into the persistence mechanisms of M.tuberculosis and suggest candidates for new drug targets and immune intervention.
The molten liquid flow inside a packed bed is a familiar momentum transportation phenomenon in a blast furnace. With regard to the reported mathematical models describing the liquid flow within a packed bed, there are some obstacles for their application in engineering design, or some limitations in the model itself. To overcome these problems, the forces from the packed bed to the liquid flow were divided into appropriate body and surface forces on the basis of three assumptions. Consequently, a new mathematical model was built to present the liquid flow inside the coke bed in a blast furnace. The mathematical model can predict the distribution of liquid flowrate and the liquid flowing range inside the packed bed at any time. The predicted results of this model accord well with the experimental data. The model will be applied considerably better in the simulation on the ironmaking process compared with the existent models.
Objective： 5-Aminoisoquinolinone, a water-soluble, potent inhibitor of the activity of poly （adenosine 5＇-diphosphate ribose） polymerase, plays an important role in the tissue injury associated with ischaemia-reperfusion injury and inflammation by inhibiting the activity of poly （adenosine 5＇-diphosphate ribose） polymerase and the expression of cell adhesion molecules such as ICAM-1, P-selectin et al. But how about it in the tumor is not clear. The aim of the present study was to study the effects of 5-Aminoisoquinolinon on the adhesion of colon carcinoma line HT-29 cells to human umbilical vein endothelial cells; and the effects of 5-Aminoisoquinolinon on the expression of ICAM-1, P-selectin and the activity of poly （adenosine 5＇-diphosphate ribose） polymerase in colon carcinoma HT-29 cells. Methods： The adhesion of HT-29 cells to human umbilical vein endothelial cells was detected by adhesive experiment. Immunocytochemically Streptavidin-Peroxidase method was used to investigate the expression of ICAM-1, P-selectin and Poly （adenosine 5＇-diphosphate ribose）（ the product of poly （adenosine 5＇-diphosphate ribose） polymerase activation）. Results： the results of the adhesion assay of HT-29 cells to HUVEC showed that the OD570 value in each 5-AIQ-treated group was significant lower than that in the control group （5-AIQ-untreated） in a dose-dependent manner. The expression of ICAM-1, P-selectin and Poly （adenosine 5＇-diphosphate ribose） was significant lower in 5-Aminoisoquinolinone-treated HT-29 cell group than that in 5-Aminoisoquinolinoneuntreated groups. Conclusion： The data suggest that 5-Aminoisoquinolinone can inhibit the adhesion of HT-29 cells to human umbilical vein endothelial cells. 5-Aminoisoquinolinone also can inhibit poly （adenosine 5＇-diphosphate ribose） polymerase activation and the expressions of ICAM-1 and P-selectin in HT-29 cells. 5-Aminoisoquinolinone probably contributes to the prevention of tumor cell metastasis. Further study is neede
Objective： To investigate the relationship of poly（ADP-ribose）glycohydrolase（PARG） with poly （ADP-ribose） polymerase（PARP）, vascular endothelial growth factor （VEGF） and basic fibroblast growth factor（b-FGF） in colorectal carcinoma（CRC）. Methods： Immunohistochemical analysis was used to detect PARG, PARP, VEGF and b-FGF in human colorectal carcinoma. Flow cytometry was used to detect PARG and PARP in murine CT26 cell line. Gallotannin （GLTN） was served as PARG inhibitor. Results： The individual positive rates of PARG, PARE VEGF and b-FGF were 55.81%（24/43）, 97.67%（42/43）, 79.07%（34/43） and 81.40%（35/43）, respectively, which were significantly higher than those of control group. The positive PARG was correlated to PARP（r=0.3703, P〈0.05） and b-FGF （r=0.4838, P〈0.05）. The positive PARP was correlated to VEGF （r=0.3968, P〈0.05） and b-FGF （r=0.5610, P〈0.05）. Both PARG and PARP were expressed in CT26 cells. The positive staining rates of PARG and PARP in GLTN-treated group were 7.3% and 52.38%, respectively. They were markedly reduced than those of control group （55.41% and 95.28%, P〈0.01, n=10000）. Conclusion： The data suggest that PARG expression probably plays a role for VEGF and b-FGF expression in colorectal carcinoma.
One of the most interesting problems of nonlinear differential equations is the construction of partial solutions. A new method is presented in this paper to seek special solutions of nonlinear diffusion equations. This method is based on seeking suitable function to satisfy Bernolli equation. Many new special solutions are obtained.
The ZnO powder with hexagonal-pyramids structure was prepared by the low-temperature combustion process. Ammonium acetate was used as the fuels, whereas zinc nitrate acted as the oxidant. The effect of different ration between fuel and oxidant on the morphology and photoluminescence （PL） characteristic was studied. The formation of hexagonal-pyramids structure was discussed. The optimum preparing parameter for fine morphology is that the ratio of zinc nitrate and ammonium acetate is 1：5, and ignition temperature is 500 ℃. The PL measurement indicates all samples have the strong blue and yellow emission peak. The changes of surface energy of the polar surfaces result in the formation of micro-pyramids structure.
Li Li~(1,2),Wei Xiantao~1,Chen Yonghu~1,Guo Changxin~1,Yin Min~(1*) (1.Department of Physics,University of Science and Technology of China,Hefei 230026, P R China) (2.College of Mathematics and Physics,Chongqing University of Posts and Telecommunications, Chongqing 400065,P R China)
Based on 33 U/Th dates and 1020 oxygen isotopic data from stalagmite Y1 from Yamen Cave, Guizhou Province, China, a record of the Asian Summer Monsoon (ASM) was established. The record covers the last deglaciation and the early Holocene (from 16.2 to 7.3 ka BP) with an average oxygen isotope resolution of 9 years. The main millennial-scale deglacial events first identified in Greenland (Greenland Interstadial Events: GIS 1e through GIS 1a) and later in China are clearly present in the Y1 record. By analogy to earlier work, we refer to these as Chinese Interstadials (CIS): CIS A.1e to CIS A.1a. The onset of these events in Y1 δ18O records are nominally dated at: 14750±50, 14100±60, 13870±80, 13370±80, and 12990±80 a BP. The end of CIS A.1a or the beginning of the Younger Dryas (YD) event is nominally at 12850±50 a BP and the end of the YD dates to 11500±40 a BP. The δ18O values shift by close to 3‰ during the transition into the Bφlling-Allerφd (BA, the onset of CIS A.1e) and at the end of the YD. Comparisons of Y1 to previously published early Holocene records show no significant phase differences. Thus, the East Asia Monsoon and the Indian Monsoon do not appear to have been out of phase during this interval. The Y1 record confirms earlier work that suggested that solar insolation and North Atlantic climate both affect the Asian Monsoon.
