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Purification and Characterization of an Extracellular Protease from Bacillus pumilus CN8
Mei-Hu Ma,Yong-Guo Jin,Hao-Li Li,Jun Wang,Ha-Na Kim,오덕환 한국식품위생안전성학회 2011 한국식품위생안전성학회지 Vol.26 No.1
The protease produced by a Bacillus pumilus CN8 strain was purified by DEAE-Cellulose-52 ion exchange. It has a molecular weight of approximately 96,920 Dalton. In the present study, this protease showed strong activity over a broad range of pH (6.5-9.5) and temperature from 40℃ to 60℃, and the protease performed the maximal activity at pH 7.3 at 42℃. The effect of metal ions on protease activity showed that K+ could slightly increase the protease activity, and other ions such as Zn²+, Fe²+, Na+, Ca²+, Mg²+ had no significant activation or inhibition to the protease (P > 0.05), and the more important is that Cu²+, Mn²+, Sn²+, Cd²+ had a strong inhibitory effect on the protease activity.
Mei Shen,Hongtao Yang,Jingjing Cheng,Mengyao Zhang,Tingting Hu,Yi Hu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12
The self-driven articulated arm coordinate measuring machine (self-driven AACMM) is a new type of flexible coordinate measuring equipment. The integrated joint module is introduced to the AACMM joint for self-driven control and automatic measurement, resulting in the joint angle error of self-driven AACMM. In this study, an ideal measurement model of the self-driven AACMM have been established. The sources of angle error of joint module is analysed, and single and comprehensive models of the joint module‘s angle error are established. Numerical simulation of the angle error model of the single joint module is conducted by MATLAB. An angle error calibration experiment of the joint module is carried out with the photoelectric autocollimator and the metal 36-sided prism. Results show that each joint module produces different torsional deformation due to load. The angle error of joint module 1, 6 are most and least affected by the load torque, the actual average errors of the two are 37.64 arcsec and -0.9632 arcsec, respectively. The simulated and calibrated single-joint module angle error trends are cyclical, and the calibrated angle error range is [-100.4 arcsec, 205.2 arcsec]. The harmonic error component in the harmonic reducer and the magnetic encoder is an important factor of the angle error of joint module. The eatablished angle error model of single joint module can be effiectively applied to comprehensive error compensation for high measurement accuracy of self-driven AACMM.
SOME RESULTS ON CONDITIONALLY UNIFORMLY STRONG MIXING SEQUENCES OF RANDOM VARIABLES
De-Mei Yuan,Xue-Mei Hu,Bao Tao 대한수학회 2014 대한수학회지 Vol.51 No.3
From the ordinary notion of uniformly strong mixing for a se- quence of random variables, a new concept called conditionally uniformly strong mixing is proposed and the relation between uniformly strong mix- ing and conditionally uniformly strong mixing is answered by examples, that is, uniformly strong mixing neither implies nor is implied by condi- tionally uniformly strong mixing. A couple of equivalent definitions and some of basic properties of conditionally uniformly strong mixing ran- dom variables are derived, and several conditional covariance inequalities are obtained. By means of these properties and conditional covariance inequalities, a conditional central limit theorem stated in terms of condi- tional characteristic functions is established, which is a conditional version of the earlier result under the non-conditional case.
Stereoselective Biotransformation of Timosaponin A-3 by Saccharomyces cerevisiae
( Yong Mei Hu ),( Zhi Ling Yu ),( Wang Fun Fong ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.6
Bioconversion of timosaponin A-III (TA-III), one of the major steroidal saponins isolated from the rhizomes of Anemarrhenae asphodeloides Bunge (Liliaceae), was investigated in Saccharomyces cerevisiae. Five bioconversion products, denoted compounds 2-6, were obtained. Biotransformation metabolite 2 was a stereoisomer of TAIII with a specific isotype F-ring and β-ranged CH3-21, which rarely occurs in nature. The structure of 2 was elucidated by extensive spectroscopic analysis (H-H COSY, HSQC, HMBC), as well as by high-resolution mass spectral analysis. The growth inhibitory activity of compounds 1-6 was assayed against four human cancer cell lines, HepG2, H-1299, HT-29, and HCT-116. Compounds 1 and 2 obviously inhibited the growth of the four types of cancer cells with IC50 values being less than 19 μM. A structure-activity relationship is discussed, and the spirostane-ring F in compounds 1 and 2 appears to be the critical bioactive moiety for the cell growth inhibitory property.
SOME RESULTS ON CONDITIONALLY UNIFORMLY STRONG MIXING SEQUENCES OF RANDOM VARIABLES
Yuan, De-Mei,Hu, Xue-Mei,Tao, Bao Korean Mathematical Society 2014 대한수학회지 Vol.51 No.3
From the ordinary notion of uniformly strong mixing for a sequence of random variables, a new concept called conditionally uniformly strong mixing is proposed and the relation between uniformly strong mixing and conditionally uniformly strong mixing is answered by examples, that is, uniformly strong mixing neither implies nor is implied by conditionally uniformly strong mixing. A couple of equivalent definitions and some of basic properties of conditionally uniformly strong mixing random variables are derived, and several conditional covariance inequalities are obtained. By means of these properties and conditional covariance inequalities, a conditional central limit theorem stated in terms of conditional characteristic functions is established, which is a conditional version of the earlier result under the non-conditional case.
Mei-rong Zhou,Zhong-hua Tang,Jing Li,Jin-Hu Fan,Yi Pang,Hong-jian Yang,Shan Zheng,Jing-qiao Bai,Ning Lv,You-Lin Qiao,Feng Xu,Hai-zhi Qi 한국유방암학회 2013 Journal of breast cancer Vol.16 No.1
Purpose: This study aims to analyze the clinical-pathological characteristics of multifocal and multicentric breast cancer (MMBC) in Chinese women. Methods: Sixty-seven cases with MMBC were randomly collected and reviewed at seven hospitals in representative districts of China during 1999 to 2008. Results: The incidence of MMBC in breast cancer in China was 1.75%. Compared to those with unifocal breast cancer, women with MMBC were more likely to have larger tumor size, lymph node metastasis (59.70% vs. 45.62%) and stage III to IV (46.26% vs. 21.10%). The peak age at onset of MMBC was 40 to 49 years old and has been gradually increasing during 1999 to 2008. Most of the MMBC women were treated with surgery and adjuvant therapy. Conclusion: In China, the incidence of MMBC in breast cancer is significantly lower than that in Western countries. Compared to unifocal breast cancer, MMBC is biologically more aggressive. Most MMBC women underwent mastectomy, instead of breast conservation surgery.
Hu-Nan Sun,Wan Fang,Mei-Hua Jin,Ying-Hao Han,Sun-Uk Kim,Sang-Han Lee,Nam-Soon Kim,Cheol-Hee Kim,Dong-Seok Lee 대한의생명과학회 2004 Biomedical Science Letters Vol.10 No.4
Inflammatory factor such as Interleukin-1 play important roles in determining the fate of both acute and chronic neurological disorders. We investigated whether inhibitors of PKC or PTK can serve as pharmacological agents to reduce IL-1 production and the mechanisms underlying their pharmacological effects in a mixed population of glia. Inhibitors of PKC such as H7, G?6976 and Ro31-8220 significantly reduced both the mRNA and protein levels of IL-1α and IL-β in lipopolysaccharide-activated primary glial cells. While the PTK inhibitor genistein also significantly reduced the production of these cytokines, it did not affect the expression of their mRNA. Taken together, inhibitors of PKC and PTK could serve as pharmacological agents to reduce IL-1 production. However, the mechanisms underlying their pharmacological effects are different. Our results provide evidence that inhibitors of protein kinases can serve as pharmacological agents to modulate IL-1 production in glial cell, and in tum, alleviate neuronal injury.
Determination of Tocopherol Contents in Refined Edible Oils Using an HPLC Method
Hu, Jiang-Ning,Zhu, Xue-Mei,Adhikari, Prakash,Li, Dan,Kim, In-Hwan,Lee, Ki-Teak The Korean Society of Food Science and Nutrition 2009 Preventive Nutrition and Food Science Vol.14 No.3
A high-performance liquid chromatography method was applied to determine the contents of tocopherols in edible oils using a LiChrosorb DIOL HPLC column and hexane fortified with 0.1% acetic acid in an isocratic mode. The validation of the method included tests for linearity, sensitivity, accuracy, precision, and recovery. All calibration curves showed good linear regression ($r^2$>0.9995) within the tested ranges. The established method offered good precision and accuracy with overall intra-day and inter-day variations of 0.94$\sim$4.27 and 1.77$\sim$ 4.88%, respectively. The tocopherol recoveries ranged from 91.44$\sim$108.90%. Subsequently, the method was successfully applied to qualitatively and quantitatively determine the total contents of $\alpha$, $\gamma$, and $\delta$-tocopherols in 12 selected refined edible oils, showing a range of 0.92 to 188.71 mg/100 g.
Hu, Hua-Bin,Kuang, Lei,Zeng, Xiao-Min,Li, Bin,Liu, En-Yi,Zhong, Mei-Zuo Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.1
Purpose: The relationship between thymidylate synthase (TS) expression and outcomes in gastric cancer (GC) patients remains controversial, although most studies reported poor survival and reduced response to fluoropyrimidine were related to high TS in tumors. We carried out a systematic review of the literature with meta-analysis to estimate the predictive value of TS expression from published studies. Methods: We indentified 24 studies analysing the outcome data in gastric cancer stratified by TS expression. Effect measures of outcome were hazard ratios (HRs) for overall survival (OS) and event-free survival (EFS), or the odds ratio (OR) for overall response rate (ORR). HRs and ORs from these eligible studies were pooled using random-effects meta-analysis. Results: Fifteen studies investigated outcomes in a total of 844 patients with advanced GC, and nine studies investigated outcomes in a total of 1,235 patients with localized GC undergoing adjuvant therapy. Meta-analysis of estimates showed high TS expression was significantly associated with poor OS in the advanced setting (HR: 1.43, 95%CI: 1.08 - 1.90), and poor EFS in the adjuvant setting (HR: 1.53, 95%CI: 1.01 - 2.32). Subgroup analysis demonstrated TS expression to haves even greater value in predicting OS, EFS and ORR in advanced GC patients treated with fluoropyrimidine monotherapy (HR for OS: 2.32, 95%CI: 1.53 - 3.50; HR for EFS: 1.76, 95%CI: 1.19 - 2.60; OR for ORR: 0.32, 95%CI: 0.11 - 0.95). Conclusion: High levels of TS expression were asssociated with a poorer OS for advanced GC patients compared with low levels. In the adjuvant setting, high TS expression was also associated with a worse EFS. Additional studies with consistent methodology are needed to define the precise predictive value of TS.