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Cementing failure of the casing-cement-rock interfaces during hydraulic fracturing
Hai Y. Zhu,Jin G. Deng,Jun Zhao,Hu Zhao,Hai L. Liu,Teng Wang 사단법인 한국계산역학회 2014 Computers and Concrete, An International Journal Vol.14 No.1
Using the principle of damage mechanics, zero-thickness pore pressure cohesive elements(PPCE) are used to simulate the casing-cement interface (CCI) and cement-rock interface (CRI). The traction-separation law describes the emergence and propagation of the PPCE. Mohr-coulomb criteria determines the elastic and plastic condition of cement sheath and rock. The finite element model (FEM) of delamination fractures emergence and propagation along the casing-cement-rock (CCR) interfaces during hydraulic fracturing is established, and the emergence and propagation of fractures along the wellbore axial and circumferential direction are simulated. Regadless of the perforation angle (the angle between the perforation and the max. horizontal principle stress), mirco-annulus will be produced alonge the wellbore circumferential direction when the cementation strength of the CCI and the CRI is less than the rock tensile strength; the delamination fractures are hard to propagate along the horizontal wellbore axial direction; emergence and propagation of delamination fractures are most likely produced on the shallow formationwhen the in-situ stresses are lower; the failure mode of cement sheath in the deep well is mainly interfaces seperation and body damange caused by cement expansion and contraction, or pressure testing and well shut-in operations.
Zhao, Hai Lin,Kim , Yeong-Shik The Pharmaceutical Society of Korea 2004 Archives of Pharmacal Research Vol.27 No.10
A 1, 2-diglyceride-based multi-step colorimetric assay to measure the pancreatic lipase activity was applied for the determination of the kinetic profiles of the lipase inhibition with a slight modification and the validity verification. With this assay method, our study revealed that platycodin D, one of major constituents of Platycodi Radix, inhibits the pancreatic lipase activity in a competitive type, with the value of $K_I$ being 0.18${\pm}$0.02 mM. In addition, PD has affected the values of $K_{m,app}\;and\;K_{cat}/K_m$ in a dose- dependent manner. The results shed a meaningful light on how PD mediates lipid metabolism in the intestinal tracts. On the other hand, since the revised assay is sensitive, rapid, and does not affect the accuracy to the kinetic properties, it is applicable not only to evaluation of the kinetic properties of the pancreatic lipase, but also to highthroughput screening of pancreatic lipase activity.
Hai Lin Zhao,Yeong Shik Kim 대한약학회 2004 Archives of Pharmacal Research Vol.27 No.9
A 1, 2-diglyceride-based multi-step colorimetric assay to measure the pancreatic lipase activity was applied for the determination of the kinetic profiles of the lipase inhibition with a slight modification and the validity verification. With this assay method, our study revealed that platycodin D, one of major constituents of Platycodi Radix, inhibits the pancreatic lipase activity in a competitive type, with the value of KI being 0.18±0.02 mM. In addition, PD has affected the values of Km, app and Kcat/Km in a dose- dependent manner. The results shed a meaningful light on how PD mediates lipid metabolism in the intestinal tracts. On the other hand, since the revised assay is sensitive, rapid, and does not affect the accuracy to the kinetic properties, it is applicable not only to evaluation of the kinetic properties of the pancreatic lipase, but also to highthroughput screening of pancreatic lipase activity.
Zhao, Hai-Un,Kim, Yeong-Shik The Pharmaceutical Society of Korea 2004 Archives of Pharmacal Research Vol.27 No.9
A 1, 2-diglyceride-based multi-step colorimetric assay to measure the pancreatic lipase activ-ity was applied for the determination of the kinetic profiles of the lipase inhibition with a slight modification and the validity verification. With this assay method, our study revealed that platy-codin D, one of major constituents of Platycodi Radix, inhibits the pancreatic lipase activity in a competitive type, with the value of $K_1$ being 0.18${\pm}$0.02 mM. In addition, PO has affected the val-ues of $K_{m}$, app/ and $K_{cat}$/$K_{m}$ in a dose-dependent manner. The results shed a meaningful light on how PO mediates lipid metabolism in the intestinal tracts. On the other hand, since the revised assay is sensitive, rapid, and does not affect the accuracy to the kinetic properties, it is applica-ble not only to evaluation of the kinetic properties of the pancreatic lipase, but also to high-throughput screening of pancreatic lipase activity.
Hai-zhen Zhao,Juan Wang,Fengxia Lv,Xiaomei Bie,Zhaoxin Lu 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.2
A water-soluble exopolysaccharide (PESP-1) was extracted and purified using DEAE Sephadex A-50 and Sephadex G-100 columns from a submerged culture broth of Pholiota squarrosa Quel. AS 5.245. PEPS-1 was investigated for antitumor activity against Heps tumors implanted in mice. An inhibition rate of 78.46% at a dosage of 100 mg/kg was observed. PEPS-1 significantly (p<0.05) increased the relative spleen/thymus indices of Heps tumor-bearing mice at a dosage of 100 mg/kg, compared with controls. Antitumor properties were probably related to stimulation of the immune response. Preliminary physicochemical analysis identified PEPS-1 as a heteropolysaccharide mainly containing D-mannose, D-glucose and D-galactose at molar ratios of 50:33:18. Small amounts of D-rhamnose and D-xylose were also detected. The average Mw of PEPS-1 was 3.26×104 Da. Structural features probably played an important role in the antitumor activity of PEPS-1.
Adsorption of Bovine Serum Albumin onto Tannic Acid-Immobilized Chitosan Resin
Hai-yan Li,Hai-mei Liu,Qin Zhao 한국섬유공학회 2020 Fibers and polymers Vol.21 No.11
A novel tannic acid-immobilized chitosan resin (TICR) was prepared by Mannich reaction for the adsorption ofproteins. The physical properties of TICR were characterized and the effects of contact time, pH, and initial concentration of(bovine serum albumin) BSA on its adsorption by TICR were investigated. The Langmuir isotherm model was applied todescribe the adsorption isotherm. The equilibrium data are fitted to the Langmuir isotherm model. The maximum monolayerBSA adsorption capacities of TICR were found to be 1.094, 1.487, and 1.694 mg/g at 298, 308, and 318 K, respectively. Furthermore, the data were analyzed on the basis of pseudo-first order, pseudo-second order, and intraparticle diffusionmodels. The correlation results suggested that the pseudo-second order model fitted the experimental data very well. Thethermodynamic study indicated that the adsorption process of BSA onto TICR was endothermic, and the Gibbs free energy(ΔGo), enthalpy (ΔHo), and entropy (ΔSo) of the adsorption process were calculated according adsorption isotherm data. TICRcould be reused for 10 times with only 19 % loss of adsorption capacity for BSA.
Cholesterol-lowering effect of platycodin D in hypercholesterolemic ICR mice
Zhao, Hai Lin,Cho, Kyung-Hyun,Ha, Young Wan,Jeong, Tae-Sook,Lee, Woo Song,Kim, Yeong Shik Elsevier 2006 european journal of pharmacology Vol.537 No.1
<P><B>Abstract</B></P><P>This study investigates the in vivo hypocholesterolemic action of platycodin D and its in vitro evidence for the cholesterol-lowering properties. In order to examine the effects of platycodin D on hypercholesterolemia in male ICR mice, platycodin D with doses of 15, 30 or 50?mg/kg was orally administered for 8 weeks. Changes in body weight and daily food intake were measured regularly during the experimental period. Final contents of triglyceride and different types of cholesterol in the serum, livers and feces were determined. The effects of platycodin D on cholesterol metabolism were further investigated with several in vitro assays, including antioxidant effect on low density lipoprotein oxidation, inhibition of human acyl-coenzyme A:cholesterol acyltransferase (hACAT) and serum lipoprotein associated-phospholipase A<SUB>2</SUB> (Lp-PLA<SUB>2</SUB>), as well as the regulation of farnesoid X receptor. The formation of insoluble complex between platycodin D and cholesterol was also investigated. Following an eight week experimental period, the body weights of platycodin D-fed mice were less than those of control mice on a high cholesterol diet by 11.2±5% (<I>P</I><0.01) with 15 mg/kg platycodin D, 11.7±5% (<I>P</I><0.01) with 30?mg/kg platycodin D, and 23.4±7.9% (<I>P</I><0.0001) with 50?mg/kg platycodin D, respectively. A decrease in daily food consumption was also noted in most of the treated animals. Triglyceride and cholesterol concentrations were decreased in serums and livers, but increased in feces. Some of the in vitro observations revealed that the hypocholesterolemic effect of platycodin D is partly associated with inhibition to hACAT activity and antagonism to the farnesoid X receptor as well as the formation of insoluble complex with between platycodin D and cholesterol. Both in vivo and in vitro results demonstrate a potential value of platycodin D as a novel cholesterol-lowering and anti-atherogenic candidate.</P>