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Study on the Kinetics and Mechanism of Grain Growth during the Thermal Decomposition of Magnesite
Da-xue Fu,Nai-xiang Feng,Yao-wu Wang 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.8
The X-ray line broadening technique was used to calculate the grain size of MgO at 1023, 1123, 1223 K respectively either in CO2 or during the thermal decomposition of magnesites in air as well as in vacuum. By referring to the conventional grain growth equation, Dn = kt, the activation energy and pre-exponential factor for the process in air are gained as 125.8 kJ/mol and 1.56 × 108 nm4/s, respectively. Ranman spectroscopy was employed to study the surface structure of MgO obtained during calcination of magnesite, by which the mechanism of grain growth was analyzed and discussed. It is suggested that a kind of highly reactive MgO is produced during the thermal decomposition of magnesites, which is exactly the reason why the activation energy of the grain growth during the thermal decomposition of magnesite is lower than that of bulk diffusion or surface diffusion.
Xiang-rong Zhang,Xiao-yan Chen,Lian-Dong Hu,Xing Tang,San-Ming Li,Da-fang Zhong 대한약학회 2005 Archives of Pharmacal Research Vol.28 No.8
The aim of this study was to compare two formulations of film-coated pellets containing clarithromycin after single oral dose study in healthy male volunteers. Two formulations with different coating polymers were prepared: formulation-1 (F-1) was prepared by incorporating three kinds of pH-dependent gradient-release coated pellets into capsules and formulation-2 (F-2) was prepared by coated with an insoluble semiosmotic film. Release profiles of filmcoated pellets were evaluated using paddle method under different conditions. Pharmacokinetic profiles of these formulations were obtained in three healthy male volunteers and compared to commercially available immediate release (IR) tablets. The relative bioavailability based on the AUC0-24 h was found to be 96.2% and 58.7% for F-1 and F-2 compared with IR, and the Tmax was delayed.
( Da Wei Chen ),( Zhen Quan Yang ),( Xia Chen ),( Yu Jun Huang ),( Bo Xing Yin ),( Fei Xiang Guo ),( Hai Qing Zhao ),( Jia Di Huang ),( Yun Wu ),( Rui Xia Gu ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.5
Accumulating evidence indicates that lactic acid bacteria could improve host physiology and lipid metabolism. To investigate the effect of the gut microbiota on host lipid metabolism, a hyperlipidemic rat model was established by feeding rats a high-fat diet for 28 days, and the gut microbiota of the rats was analyzed using real-time PCR before and after administration of Lactobacillus rhamnosus hsryfm 1301 and its fermented milk for 28 days. The findings showed that the Lactobacillus spp., Bifidobacterium spp., Bacteroides spp., and Enterococcus spp. content in the hyperlipidemic rats gut was increased significantly (p < 0.05), while the Clostridium leptum and Enterobacter spp. content was decreased significantly after intervening with L. rhamnosus hrsyfm 1301 and its fermented milk for 28 days (p < 0.05). Furthermore, the lipid levels of the serum and the liver were decreased significantly (p < 0.05) and the fecal water content was increased significantly (p < 0.05) in the hyperlipidemic rats after the intervention, and hepatocyte fatty degeneration of liver tissues was also prevented. A positive correlation was observed between the Clostridium leptum content and the level of serum cholesterol, triglycerides, low-density lipoprotein, and high-density lipoprotein, and a negative correlation was observed between the Enterobacter spp. content and the Lactobacillus spp. and Bifidobacterium spp. content in the hyperlipidemic rats gut. These results suggest that the gut microbiota and lipid metabolism of hyperlipidemic rats could be improved by supplementation with L. rhamnosus hsryfm 1301 and its fermented milk.
Numerical Study on Stress Intensity Factors for Stud Connectors of Steel–Concrete Connection
Da Wang,Benkun Tan,Lei Wang,Fanghuai Chen,Shengtao Xiang 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.5
The fatigue fracture of the stud connector is the main failure mode of the steel–concrete composite structure. Fatigue assessment of cracked stud connectors with weld details is conducted in this study by using the linear elastic fracture mechanics approach. The mixed-mode stress intensity factor is calculated by the M -integral method, and the relative crack position h c is considered. First, a 3D fi nite element model of the push-out test with stud welding details is proposed in this study, and the load–slip curve and stress distribution of the stud connector were analyzed. Then, the mixed-mode stress intensity factor was calculated by defi ning the sub-model with cracks, and the infl uence coeffi cient of the mixed-mode stress intensity factor was investigated. The important infl uencing parameters, which include the crack aspect ratio, relative crack height, stud diameter, and stud height, are combined for calculation. The mixed-mode stress intensity factor of the stud is dominated by mode I (open). The infl uence of the stud height is not observed. However, the stress intensity factor of the crack tip gradually increases with the stud diameter. The study also found the infl uence of the crack shape under various conditions. The results of this study can be used by researchers to evaluate the fatigue fracture conditions of stud connectors.
Expression of C4.4A is a Potential Independent Prognostic Factor for Patients with Gastric Cancer
Cheng, Da-Qing,Gu, Xiao-Dong,Li, Zhen-Yang,Xiang, Jian-Bin,Chen, Zong-You Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.9
C4.4A, a metastasis-associated gene, encodes a glycolipid-anchored membrane protein which is overexpressed in several human malignancies. However, there are few data available on C4.4A expression and its relationship with progression in gastric cancer. Our study was designed to explore the expression of C4.4A in gastric cancer and to correlate it with clinical outcome. C4.4A expression was studied by quantitative real-time RT-PCR and immunohistochemistry for assessment of correlations with clinicopathological factors. C4.4A mRNA expression was significantly up-regulated in gastric cancer as compared with noncancerous tissue (p<0.05)., being observed in 107 (88.4%) of the 121 gastric cancer cases by immunohistochemistry. We found that the expression of C4.4A mRNA was correlated with size of the tumor, depth of invasion, lymph node metastasis, distant metastasis and TNM stage. Moreover, patients with overexpression of C4.4A has a significantly worse survival (p<0.05). Further multivariable analysis indicated that the expression of C4.4A was an independent prognostic indicator for gastric cancer (p<0.05). In conclusion, overexpression of C4.4A correlates with metastatic potential of gastric cancer and C4.4A could be a novel independent prognostic marker for predicting outcome.
Study on the Kinetics and Mechanism of Grain Growth during the Thermal Decomposition of Magnesite
Fu, Da-Xue,Feng, Nai-Xiang,Wang, Yao-Wu Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.8
The X-ray line broadening technique was used to calculate the grain size of MgO at 1023, 1123, 1223 K respectively either in $CO_2$ or during the thermal decomposition of magnesites in air as well as in vacuum. By referring to the conventional grain growth equation, $D^n=kt$, the activation energy and pre-exponential factor for the process in air are gained as 125.8 kJ/mol and $1.56{\times}10^8\;nm^4/s$, respectively. Ranman spectroscopy was employed to study the surface structure of MgO obtained during calcination of magnesite, by which the mechanism of grain growth was analyzed and discussed. It is suggested that a kind of highly reactive MgO is produced during the thermal decomposition of magnesites, which is exactly the reason why the activation energy of the grain growth during the thermal decomposition of magnesite is lower than that of bulk diffusion or surface diffusion.
Zhang Xiang-rong,Chen Xiao-yan,Hu Lian-Dong,Tang Xing,Li San-Ming,Zhong Da-fang The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.8
The aim of this study was to compare two formulations of film-coated pellets containing c1arithromycin after single oral dose study in healthy male volunteers. Two formulations with different coating polymers were prepared: formulation-1 (F-1) was prepared by incorporating three kinds of pH-dependent gradient-release coated pellets into capsules and formulation-2 (F-2) was prepared by coated with an insoluble semiosmotic film. Release profiles of filmcoated pellets were evaluated using paddle method under different conditions. Pharmacokinetic profiles of these formulations were obtained in three healthy male volunteers and compared to commercially available immediate release (IR) tablets. The relative bioavailability based on the $AUC_{0-24h}$ was found to be $96.2\%\;and\;58.7\%$ for F-1 and F-2 compared with IR, and the $T_{max}$ was delayed.
Molecular organization of the B mating type locus of a Lentinula edodes monokaryon strain SUP2
Bao Da-Peng Chen Ming-Jie,Song Wen-Hua,Song Chun-yan,Zhang Mei-Yan,Chen Xiang,Lin Nan 한국버섯학회 2010 한국버섯학회지 Vol.8 No.4
Lentinula edodes is an important cultivated mushroom in China. The development of Lentinula edodes production promotes more studies on it. In our previous work, degenerate PCR and chromosome walking technologies were used to obtain one pheromone receptor gene and one pheromone precursor gene from Lentinula edodes. In this study, four pairs of specific primers were designed according to the whole genome sequencing of the protoplast monokaryon of Lentinula edodes strain 135, to amplify STE3-like pheromone receptor gene and its flanking conserved genes in the protoplast monokaryon strain SUP2 derived from Lentinula edodes strain Suxiang and 33655bp DNA sequence was obtained. By BlastX search, seven putative genes were identified, and three of them are pheromone receptor encoded genes. Furthermore, near to two pheromone receptor genes, four genes encoding proteins with conserved motifs of pheromone precursors were found. This study firstly reveals the molecular organization of the B mating type locus of Lentinula edodes.