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Mechanism of Yanghe Pingchaun granules on airway remodeling in asthmatic rats based on IL-6/JAK2/STAT3 signaling axis
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作者 LV Chuan ZHU Hui-zhi +4 位作者 LIU Xiang-guo CAO Xiao-mei XIA Yong-qi ZHANG Qiu-ping YU Zi-qi 《Journal of Hainan Medical University》 CAS 2024年第1期15-21,共7页
Objective: To investigate the effects of Yanghe Pingchuan Granules on airway remodeling in asthmatic rats, and to explore the mechanism of Interleukin-6/Janus kinase 2/ Signal transducing activator of transcription 3(... Objective: To investigate the effects of Yanghe Pingchuan Granules on airway remodeling in asthmatic rats, and to explore the mechanism of Interleukin-6/Janus kinase 2/ Signal transducing activator of transcription 3(IL-6/JAK2/STAT3) signal axis. Methods: We separated 42 healthy male SD rats into two groups, a control group (7) and a model group (35).The model group was sensitized with a combination of ovalbumin (OVA) and aluminum hydroxide for 2 weeks, while the control group was given an equal amount of physiological saline.After 2 weeks, the modeling group was randomly divided into Model group, Yanghe Pingchuan Granules high, medium and low dose groups and Dexamethasone group, each group consisted of 7 animals. After 4 weeks, OVA atomization and gavage were used for stimulation and treatment. Yanghe Pingchuan Granules high, middle and low groups were given 15.48, 7.74, 3.87 g∙kg-1 Yanghe Pingchuan Granules daily, dexamethasone group was given 0.0625 mg∙kg-1 dexamethasone daily, and the other groups were given the same amount of normal saline. HE, PAS and Masson staining were used to observe the lung histopathological changes in rats. The levels of interleukin-6, IL-23 and IL-17A were detected by ELISA. The expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 in lung tissues were detected by Western blot. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect the mRNA expression levels of IL-6, JAK2 and STAT3 in rat lung tissue. Results: The lung tissue structure of the model group was severely damaged compared to the control group, accompanied by a great many of inflammatory cell infiltration, goblet cell hyperplasia, subepithelial collagen fiber deposition and airway epithelial thickening were more obvious. The expressions of IL-6, IL- 23 and IL-17A in serum were significantly increased (P<0.01), the protein expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 and the mRNA expression levels of IL-6, JAK2 and STAT3 in lung tissue were significantly increased (P<0.01);Compared with the model group, inflammatory cell infiltration, goblet cell proliferation, subepithelial collagen fiber deposition and airway epithelial thickening were significantly reduced in each administration group, and the expressions of IL-6, IL-23 and IL-17A in serum were significantly decreased (P< 0.01). The protein expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 and mRNA expression levels of IL-6, JAK2 and STAT3 in lung tissue were significantly decreased (P<0.01). Conclusion: Yanghe Pingchuan Granules can significantly alleviate airway remodeling in asthmatic rats, and its mechanism may be through inhibiting the IL-6/JAK2/STAT3 signal axis. 展开更多
关键词 Yanghe Pingchuan Granules Interleukin-6/Janus kinase 2/Signal transducing activator of transcription 3(IL-6/JAK2/STAT3)signal axis Asthma Airway remodeling Mechanism study
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Mechanism study on UV-induced photodegradation of nonylphenol ethoxylates by intermediate products analysis 被引量:8
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作者 Ling Chen Hai Yun Zhou +1 位作者 Lan Liu Qin Ying Deng 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第4期473-475,共3页
Photodegradation of nonylphenol ethoxylates (NPloEO) was investigated in laboratory scale under UV irradiation. The intermediate photodegradation products were analyzed by LC-ESI-MS. Three kinds of intermediate prod... Photodegradation of nonylphenol ethoxylates (NPloEO) was investigated in laboratory scale under UV irradiation. The intermediate photodegradation products were analyzed by LC-ESI-MS. Three kinds of intermediate products including aldehydic compounds, carboxylic compounds and cyclohexanyl compounds were identified. Five main degradation routes involving the oxidation of the alkyl chain and ethoxylate unit, shortening of the alkyl chain and ethoxylate unit, hydrogenation of the benzene ring were proposed. 展开更多
关键词 PHOTODEGRADATION Nonylphenol ethoxylates Intermediate products Mechanism study
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Chemiluminescence determination of 20 amino acids and the mechanism study 被引量:3
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作者 Yan Ming Liu Zhuan Li Liu 《Chinese Chemical Letters》 SCIE CAS CSCD 2010年第7期856-859,共4页
It was found that 20 amino acids could inhibit the intensity of the luminol-H_2O_2-CuSO_4 chemiluminescence system.Using this character,a rapid and sensitive method for the determination of 20 amino acids was develope... It was found that 20 amino acids could inhibit the intensity of the luminol-H_2O_2-CuSO_4 chemiluminescence system.Using this character,a rapid and sensitive method for the determination of 20 amino acids was developed with flow injection coupled with chemiluminescence detection.Under the optimal conditions,the detection limits of 20 amino acids were in the range of 4.5×10^(-7)- 4.3×10^(-10) mol/L,and the relative standard deviations were less than 3.2%.The proposed method was successfully applied to drug analysis.The possible mechanism was also discussed. 展开更多
关键词 CHEMILUMINESCENCE Flow injection Amino acid Mechanism study
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Okadaic acid: a tool to study regulatory mechanisms for neurodegeneration and regeneration in Alzheimer's disease 被引量:4
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作者 Pradip Kumar Kamat Chandishwar Nath 《Neural Regeneration Research》 SCIE CAS CSCD 2015年第3期365-367,共3页
Okadaic acid: Okadaic acid (OKA), a polyether (C38 fatty acid) toxin, is a potent and selective inhibitor of protein phosphatase, PP1 and protein phosphatase 2A (PP2A). It is mainly extracted from a black spong... Okadaic acid: Okadaic acid (OKA), a polyether (C38 fatty acid) toxin, is a potent and selective inhibitor of protein phosphatase, PP1 and protein phosphatase 2A (PP2A). It is mainly extracted from a black sponge Hallichondria okadaii and has been suggested to play a potent probe for studying the various molecular, cellular, biochemical and mechanism of neurotoxicity. It is known as a selective and potent in- hibitor of serine/threonine phosphatases 1 and 2A induces hyperphosphorylation of tau in vitro and in vivo. It has been reported that Alzheimer's disease (AD) is a complex multi- factorial neurodegenerative disorder and hyperphosphor- ylated tau protein is a major pathological hallmark of AD. The reduced activity of phosphatases like, PP2A has been implicated in the brain of AD patients. OKA also induced inhibition of protein phosphatases cause neurofibrillary tangles (NFTs) like pathological changes and tau hyperphos- phorylation seen in AD pathology. Our and others reports inferred that OKA induces neurodegeneration along with tau hyperphosphorylation, GSK3β activation, oxidative stress, neuroinflammation and neurotoxicity which are char- acteristic of AD pathology (Figure 1). 展开更多
关键词 a tool to study regulatory mechanisms for neurodegeneration and regeneration in Alzheimer’s disease Okadaic acid AD
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A Numerical Study on the Mechanisms Producing Forces on Cylinders Interacting with Stratified Shear Environments 被引量:1
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作者 Yin Wang Lingling Wang +2 位作者 Yong Ji Zhicheng Xi Wenwen Zhang 《Fluid Dynamics & Materials Processing》 EI 2021年第2期471-485,共15页
A three dimensional(3D)numerical wave flume is used to investigate carefully the ISWs(Internal solitary wave)forces acting on cylinders interacting with a stratified shear environment.Using the Large-Eddy Simulation(L... A three dimensional(3D)numerical wave flume is used to investigate carefully the ISWs(Internal solitary wave)forces acting on cylinders interacting with a stratified shear environment.Using the Large-Eddy Simulation(LES)approach and analyzing the distribution of shear stress and pressure along the surface of the cylinder,the differential pressure resistance and the viscous force are obtained.The method of multiple linear regression analysis is adopted and a comprehensive influence coefficient is determined accordingly to account for the dimensionless forces acting on the cylinder.Results show that the differential pressure resistance on a square cylinder is 1.5 times higher than that on a circular cylinder in the upper layer,while the differential pressure resistance on a square cylinder is 3.5 times larger than that on a circular cylinder in the lower layer.The viscous force is 1–2 orders of magnitude smaller than the differential pressure resistance,which means that the viscous force could be ignored.The comprehensive influence coefficient shows positive correlation with the relative wave height and negative correlation with upper and lower water depth ratio. 展开更多
关键词 Internal solitary waves cylinders force behaviors mechanism study numerical simulation
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Clinical Observation on Treatment of 78 Patients of B-Thalassemla with Bushen Ylsul (补肾益髓) Method and Study on Its Molecular Mechanism 被引量:6
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作者 吴志奎 蔡辉国 +7 位作者 方素萍 张新华 王蕾 陈玉英 吕鑫霞 黄有文 王荣新 陈佩珍 《Chinese Journal of Integrated Traditional and Western Medicine》 2003年第2期141-141,共1页
Objective: To study the treatment of B-Thalas-semia (ThE) with Chinese herbal medicine for Bushen Yisui (BSYS), its theoretical base and molecular mechanism. Methods: Seventy-eight patients with ThE were treated with ... Objective: To study the treatment of B-Thalas-semia (ThE) with Chinese herbal medicine for Bushen Yisui (BSYS), its theoretical base and molecular mechanism. Methods: Seventy-eight patients with ThE were treated with BSYS recipe (consisted of 11 Chinese herbal drugs as Dogwood fruit, Fleeceflower root, prepared Rehmannia root and turtle shell, etc.) orally taken, 3 times per day, 10 g/time, 3 months as one therapeutic course. Hemoglobin (Hb), red blood cell (RBC), reticulocyte (Ret) and hemoglobin F (HbF) were checked every month. At the same time, PAGE, PVR, PCR-SSCP, RT-PCR, DNA series analysis, mRNA gene expression analysis techniques were used to conduct the systematic gene analysis in patients to study the molecular mechanism of TCM treatment from aspects of gene mutation, gene expression and control-regulation. Results: All the blood criteria in patients after BSYS treatment were improved significantly with clinical symptoms 展开更多
关键词 of in gene Method and study on Its Molecular Mechanism Clinical Observation on Treatment of 78 Patients of B-Thalassemla with Bushen Ylsul HbF on with
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Parametric study of control mechanism of cortical bone remodeling under mechanical stimulus 被引量:1
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作者 YananWang Qing-Hua Qin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第1期37-44,共8页
The control mechanism of mechanical bone remodeling at cellular level was investigated by means of an extensive parametric study on a theoretical model described in this paper. From a perspective of control mechanism,... The control mechanism of mechanical bone remodeling at cellular level was investigated by means of an extensive parametric study on a theoretical model described in this paper. From a perspective of control mechanism, it was found that there are several control mechanisms working simultaneously in bone remodeling which is a complex process. Typically, an extensive parametric study was carried out for investigating model parameter space related to cell differentiation and apoptosis which can describe the fundamental cell lineage behaviors. After analyzing all the combinations of 728 permutations in six model parameters, we have identified a small number of parameter combinations that can lead to physiologically realistic responses which are similar to theoretically idealized physiological responses. The results presented in the work enhanced our understanding on mechanical bone remodeling and the identified control mechanisms can help researchers to develop combined pharmacological-mechanical therapies to treat bone loss diseases such as osteoporosis. 展开更多
关键词 Control mechanism Parametric study Mechanical bone remodeling
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STUDY ON THE ANTI-TUMOR EFFICACY INDUCED BY HEAT SHOCK PROTEIN 70-PEPTIDE COMPLEXES DERIVED FROM TUMOR CELLS 被引量:6
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作者 傅庆国 张玮 +2 位作者 孟凡东 郭仁宣 姚振宇 《Chinese Medical Sciences Journal》 CAS CSCD 2002年第3期153-156,共4页
OBJECTIVE: To study the efficacy and explore the mechanism of the anti-tumor immunity elicited by heat shock protein 70-peptide complexes (HSP70-PC) derived from tumor cells. METHODS: Cells culture, flow cytometric an... OBJECTIVE: To study the efficacy and explore the mechanism of the anti-tumor immunity elicited by heat shock protein 70-peptide complexes (HSP70-PC) derived from tumor cells. METHODS: Cells culture, flow cytometric analysis, affinity chromatography for protein purification, SDS-PAGE, Western-blotting and animal experiment were used. RESULTS: HSP70-PC immunization rendered protective effect to both naive tumorl-bearing mice. All of the naive mice obtained complete resistance to Hcaf cell attack; 40% of the tumor-bearing mice survived for over 90 days, whereas the mice of control group died within 2 weeks (P 展开更多
关键词 NEOPLASM heat shock protein 70 peptide complexes tumor vaccineObjective. To study the efficacy and explore the mechanism of the anti tumor immunity elicited by heat shock protein 70 peptide complexes (HSP70 PC) derived from tumor cells. M
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Mossbauer Study of Mechanica Aloying Fe-Ti and Fe-Ti-N Alloys
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《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第1期1-2,共2页
关键词 TI FE ssbauer study of Mechanical Alloying Fe-Ti and Fe-Ti-N Alloys
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Study on the Protective Mechanism of Acupuncture Regulating ICAM-5 mRNA Expression in Rats with Ischemic Stroke
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作者 Yating Shen Ximei Xie +4 位作者 Xiu Bai Hua Bai Xiaofan Chang Yuanyuan Tang Qiuyu Li 《Journal of Behavioral and Brain Science》 2021年第12期313-321,共9页
<b>Objective:</b> The objective is to investigate whether acupuncture can protect brain by regulating the expression of ICAM-5 mRNA in brain tissue. <b>Methods:</b> Male SD rats were used to co... <b>Objective:</b> The objective is to investigate whether acupuncture can protect brain by regulating the expression of ICAM-5 mRNA in brain tissue. <b>Methods:</b> Male SD rats were used to construct a middle cerebral artery occlusion reperfusion injury (Middle cerebral artery occlusion, MCAO) model, and the rats were randomly divided into 4 groups, namely the normal group (group A) and the sham operation group (group B), MCAO group (group C), MCAO + acupuncture group (group D);real-time fluorescent quantitative PCR (RT-qPCR) was used to detect the expression of ICAM-5 mRNA in the brain tissue of the ischemic area, and HE staining and TUNEL were used to detect the level of neuronal apoptosis to evaluate the therapeutic effect. <b>Results:</b> Acupuncture can improve neuronal morphology and reduce neuronal apoptosis in rats with ischemic stroke. RT-qPCR: compared with group A and group B, the expression level of ICAM-5 mRNA in the brain tissues of group C and group D decreased, while compared with group C, The expression of ICAM-5 mRNA in the brain tissue of group D was significantly up-regulated (P < 0.05). There was no statistical difference between group A and group B (P > 0.05). <b>Conclusion:</b> The effectiveness of acupuncture in the treatment of ischemic stroke may achieve neuroprotection by up-regulating the expression level of ICAM-5 mRNA. 展开更多
关键词 Ischemic Stroke ACUPUNCTURE ICAM-5 mRNA Mechanism study
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A Mssbauer Study on the Mechanically Alloyed Cu-Sn Alloys
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作者 Yuanzheng YANG Youlan ZHU and Qiaoshen LI(Dept. of Materials Science and Engineering, Guangdong University of Technology, Guangzhou 510090, China)Xueming MA and Yuanda DONG(Dept. of Materials Science and Engineering, Shanghai University, Shanghai 200072, 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1998年第6期551-554,共4页
Nanocrystalline E and η electron compounds and supersaturated solid solution of the Cu-Sn system have been prepared by mechanical alloying of elemental Cu and Sn powders. The atomie alloying and microstructure of the... Nanocrystalline E and η electron compounds and supersaturated solid solution of the Cu-Sn system have been prepared by mechanical alloying of elemental Cu and Sn powders. The atomie alloying and microstructure of the resultant alloys have been investigated by XRD, DSC and 119Sn Mossbauer spectroscopy. A little amount of SnO2 was detected by Mossbauer spectroscopy, although no trace of diffiaction peaks occurred in the XRD pattern. Thus the spectra for all the milled samples should be fitted using two quadrupole-splitting doublets: one corre sponding to SnO2, the other corresponding to the resultant alloys. The composition dependence of the hyperfine parameters has been eXtensively discussed and explained well with respect to oxidation, sudece effect resulting from grain refinement, coordination environment asymmetry and distortion caused or/and induced by mechanical alloying. 展开更多
关键词 SN A M ssbauer study on the Mechanically Alloyed Cu-Sn Alloys CU
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A STUDY ON MECHANICAL MODEL OF THE HELICOPTER "GROUND RESONANCE
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作者 Gu Zhong-quan Nanjing Aeronautical Institute 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1991年第4期354-360,共7页
The key problem to the calculation and optimization design of the helicopter 'Ground Resonance' is to correctly build up a mechanical model. In the past, the literature was only concerned with the lag modes of... The key problem to the calculation and optimization design of the helicopter 'Ground Resonance' is to correctly build up a mechanical model. In the past, the literature was only concerned with the lag modes of the rotor blade and the flap modes were neglected. But such approaches should be reconsidered now. In order to study the influences of rotating multiblades rotor on the degrees of freedom and also the flap ''Ground Resonance' of a helicopter, it is necessary to consider not only the lag degrees of freedom but also the flap degrees of freedom. Using Lagrangian equation a dynamical equation of the space model for helicopter 'Ground Resonance'is deduced for the first time. Some computation results show that the mechanical model including both lag DOF and flap DOF is more reasonable. 展开更多
关键词 GROUND RESONANCE A study ON MECHANICAL MODEL OF THE HELICOPTER
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First Principles Study on Mechanical Properties of Superhard α-Ga Boron
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作者 徐源慧 刘会云 +2 位作者 郝险峰 陈蓉娜 高发明 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第2期95-98,共4页
The mechanical properties and intrinsic hardness of the α-Ga boron phase (α-Ga-B) are studied by using the combination of first-principles calculations and a semiempirieal macroscopic hardness model. It is found t... The mechanical properties and intrinsic hardness of the α-Ga boron phase (α-Ga-B) are studied by using the combination of first-principles calculations and a semiempirieal macroscopic hardness model. It is found that α- Ga-B is mechanically stable and possesses higher bulk/shear modulus as compared with γ-B28, a newly discovered high-pressure boron phase. The theoretical hardness of α-Ga-B is estimated to be 45 GPa, which is much higher than 38 GPa for γ-B28. The results strongly indicate that α-Ga-B is a potential superhard boron phase. To further obtain insight into the superhard nature of α-Ga-B, we simulate stress-strain curves under tensile and shear deformation. Meanwhile, the microscopic mechanism driving the tensile and shear deformation modes in α-Ga-B is discussed in detail. 展开更多
关键词 Ga Boron First Principles study on Mechanical Properties of Superhard
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Study on the Mechanism of the Rearrangement Reaction of 3-n-Butylphthalide by Deuterium-Labelling
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作者 Bai Ling XU Zong Ru GUO +1 位作者 Xiao Tian LIANG Guang Zhong YANG (Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050) 《Chinese Chemical Letters》 SCIE CAS CSCD 1997年第6期479-482,共4页
By the Grignard reaction of 1,1-di-deutero-1-bromobutane with phthalaldehydic acid 1',1'-di-deutero-3-n-butyl phthalide was obtained, which underwent a rearrangement reaction using AlCl3 as catalyst in CS2 to ... By the Grignard reaction of 1,1-di-deutero-1-bromobutane with phthalaldehydic acid 1',1'-di-deutero-3-n-butyl phthalide was obtained, which underwent a rearrangement reaction using AlCl3 as catalyst in CS2 to give 1-methyl-5-carboxy-3,4-di-deutero-tetrahydronaphthalene. The mechanism was proposed to be a series of consecutive 1,2- hydride transfers rather than a direct 1,4-hydride transfer. 展开更多
关键词 PPM CHD study on the Mechanism of the Rearrangement Reaction of 3-n-Butylphthalide by Deuterium-Labelling
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DSC STUDY ON THE WATER-ABSORBING MECHANISM OF PLASMA POLYMERIZED N-VINYL-2-PYROROLIDONE
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作者 Ding Sheng YU R.E.MARCHANT 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第11期889-892,共4页
Water existing in water-absorbing plasma polymerized N-vinyl-2-pyrrolidone(PPNVP) include pure bulk water, freezable water and non-freezing, or bound, water. The C-N bond of N, N-disubstituted amides in PPNVP was cons... Water existing in water-absorbing plasma polymerized N-vinyl-2-pyrrolidone(PPNVP) include pure bulk water, freezable water and non-freezing, or bound, water. The C-N bond of N, N-disubstituted amides in PPNVP was considered as an active binding site for bound water. 展开更多
关键词 DSC study ON THE WATER-ABSORBING MECHANISM OF PLASMA POLYMERIZED N-VINYL-2-PYROROLIDONE 加加 ESCA NVP
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An AM1 Study on the Mechanism of Uridine Phospborolysis
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《Chinese Chemical Letters》 SCIE CAS CSCD 1996年第11期999-1002,共4页
We have cd quantum chemical method tO ho the transition states of uridinephosphorolysis reaction under the neutral condition. Comparing the activation energies ofdifferent reaction modes, we conclude that uridine p... We have cd quantum chemical method tO ho the transition states of uridinephosphorolysis reaction under the neutral condition. Comparing the activation energies ofdifferent reaction modes, we conclude that uridine phosphorolysis takes Place mainlyaccording tO a concerted mechanism. The computational are consistent with somecritical experimental factsss. 展开更多
关键词 AM An AM1 study on the Mechanism of Uridine Phospborolysis
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THE STUDY ON THE MASS TRANSFER MECHANISM OF EUROPIUM ION THROUGH LIQUID SURFACTANT MEMBRANES
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作者 姜长印 郁建涵 朱永(贝睿) 《Chinese Journal of Chemical Engineering》 SCIE EI CAS 1985年第1期11-19,共9页
The transfer of trivalent europium ion in a liquid surfactant membrane system is investigated in order toclarify the characteristics of liquid membrane separation process and the availability of this technique forreco... The transfer of trivalent europium ion in a liquid surfactant membrane system is investigated in order toclarify the characteristics of liquid membrane separation process and the availability of this technique forrecovering trivalent lanthanides and actinides.A layered structure model for the emulsion globule is sug-gested.The equations describing the relationship among the effective membrane thickness,the time andother factors are derived and verified experimentally.Results show that under certain conditions the decreas-ing concentration of europium ion in the external phase is proportional to the square root of the time,the acidity of the internal phase and the carrier concentration in the membrane phase.The membrane phase consists of kerosene(solvent),Span-80(surfactant)and di-(2-ethylhexyl) phosphoricacid(HDEHP,carrier).The internal phase is dilute nitric acid and the external phase is aqueous solu-tion containing Eu(NO3)3.The mass transfer rate of europium in this system is high and the recovery ofeuropium may be more than 99%. 展开更多
关键词 FIGURE show Eu HAZ THE study ON THE MASS TRANSFER MECHANISM OF EUROPIUM ION THROUGH LIQUID SURFACTANT MEMBRANES
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THE STUDY ON TRE KINETICS AND MECHANISM OF THE REACTIONS OF METAL IONS WITH PnAO
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作者 Bin SONG Qi Yan ZHANG Yun Ti CHEN Department of Chemistry,Nankai University,Tianjin,300071R.K.MURMANN Department of Chemistry,University of Missouri,Columbia,65211,USA Biotechnology reseach center,Zhongshan University,Guangzhou,510275 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第7期569-570,共2页
The kinetics and the mechanism of the formation reactions of M(PnAO)^(2+)(M=Ni,Co,Cu)were studied with UV Spectrophotometer and Stopped Flow Spectrophotometer and a three steps mechanism was suggested.
关键词 NI CO THE study ON TRE KINETICS AND MECHANISM OF THE REACTIONS OF METAL IONS WITH PnAO
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A Numerical Study of the Mechanism for the Effect of Northern Winter Arctic Ice Cover on the Global Short-Range Climate Evolution
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作者 倪允琪 张勤 李跃东 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1991年第4期489-498,共10页
By using a nine-layer global spectral model involving fuller parameterization of physical processes, with a rhomboidal truncation at wavenumber 15, experiments are performed in terms of two numerical schemes, one with... By using a nine-layer global spectral model involving fuller parameterization of physical processes, with a rhomboidal truncation at wavenumber 15, experiments are performed in terms of two numerical schemes, one with long-term mean coverage of Arctic ice (Exp.1), the other without the ice (Exp.2). Results indicate that the Arctic region is a heat source in Exp.2 relative to the case in Exp.1. Under the influence of the polar heat source simulated, there still exist stationary wavetrains that produce WA-EUP and weak PNA patterns in Northern winter. That either the Arctic or the tropical heat source can cause identical climatic effects is due to the fact that the anomaly of the Arctic ice cover will directly induce a south-propagating wavetrain, and bring about the redistribution of the tropical heat source / sink. The redistribution is responsible for new wavetrains that will exert impact on the global climate. The simulation results bear out further that the polar region in Exp.2 as a heat source, can produce, by local forcing, a pair of positive and negative difference centers, which circle the Arctic moving eastwards. Observed in the Northern Hemisphere extratropics is a 40-50 day oscillation in relation to the moving pair, both having the same period. 展开更多
关键词 over A Numerical study of the Mechanism for the Effect of Northern Winter Arctic Ice Cover on the Global Short-Range Climate Evolution
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STUDY ON THE SEPARATION AND EXTRACTION MECHANISM OF RARE EARTH ELEMENTS BY MEANS OF REVERSED-PHASE PAPER CHROMATOGRAPHY
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作者 Wang Yingwei Zheng Jianxiang(Department of Chemistry,Xiangtan University,Xiangtan 411105,P.R.China) 《Journal of Rare Earths》 SCIE EI CAS CSCD 1990年第1期15-20,共6页
Reversed-phase paper chromatography technique is used for study on the extraction mechanism and sep- aration of rare earth elements.As the stationary phase,chromatographic paper strips are impregnated with a solution ... Reversed-phase paper chromatography technique is used for study on the extraction mechanism and sep- aration of rare earth elements.As the stationary phase,chromatographic paper strips are impregnated with a solution of monomyristyl phosphoric acid (MPA) in chloroform.Mineral acids are used as developers. The effect of concentration of acids and/or salts upon R_f has been investigated.According to the re- sults of R_f values for a given rare earth element in various acids,the order of extraction ability is HCl>HNO_3>H_2SO_4.A tetrad effect is clearly observed.for the R_f value of rare earth elements.The effects of other parameters on the R_f value,such as the quantities of extractant retained by the paper and the temperature are also examined.Based on the determination of the molar ratio of MPA to rare earth elements and the number of H^+ ions released in extraction reaction,a reasonable mechanism is proposed.The mutual separation of heavy rare earth elements will be better than that of the light rare earth group because of the larger separation coefficient of the former.A mixture of Ho-Er-Tm-Lu is successfully separated by the present method. 展开更多
关键词 than study ON THE SEPARATION AND EXTRACTION MECHANISM OF RARE EARTH ELEMENTS BY MEANS OF REVERSED-PHASE PAPER CHROMATOGRAPHY Eu HCI MPA
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