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A comparative study of four 20-membered N_2S_4-crown ethers as ionophores for polymeric membrane silver selective electrodes 被引量:4
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作者 Zhang, Jun Yu, Shun Yang +2 位作者 Yin, Tan Ji Hu, Xue Feng Qin, Wei 《Chinese Chemical Letters》 SCIE CAS CSCD 2010年第4期464-467,共4页
Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effe... Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effect on the selectivity and sensitivity to Ag^+ ions.The electrode based on ionophore 9,10,20,25-tetrahydro-5H,12H-tribenzo[b,n,r][1,7,10,16,4,13]tetrathiadiaza cycloicosine 6,13-(7H,14H)-dione(C) with 2-nitrophenyl octyl ether(o-NPOE) as solvent in a poly(vinyl chloride)(PVC) membrane matrix sho... 展开更多
关键词 Ion-selective electrodes SILVER ionophore Azathiacrown ether
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INDUCTION OF ECTODERMAL CELLS FROM VEGETALENDODERMAL BLASTOMERES OF AMPHIOXUS(BRANCHIOSTOMA BELCHERI TSINGTAUNESE) EMBRYOS BY THE CALCIUM IONOPHORE A23187 被引量:1
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作者 张士璀 郑家声 +1 位作者 张红卫 毛炳宇 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1999年第2期97-104,共8页
Timing of vegetal-endodermal cell determination in amphioxus embryos remains uncertain. We tentatively testal effects of A23187, the calcium ionophore, on the deveopment of vegetal blastomeres isolated at the 16-cell ... Timing of vegetal-endodermal cell determination in amphioxus embryos remains uncertain. We tentatively testal effects of A23187, the calcium ionophore, on the deveopment of vegetal blastomeres isolated at the 16-cell stage. It was found that when vegetal blastomres committed to endodermwere treated with A23187 prior to gastrulation, they were transformed into ectodermal cells as evidenced by the cell morphology and function characteristic of epidermis. Howver, the developmental fate of the sam blastomeres untreated or treated with DMSO at the same stage or of those treated with A23187 after gastrulation remained unchanged. Thus, vegetal-endodermal cells in amphioxus embryos are not irreversibly deermined before the gastrula stage, and artificial incarease in intracelluar Ca2+ concentration can induce transdetermination of the predetermined endodermal cells into ectodermal cells. 展开更多
关键词 AMPHIOXUS ectodermal CELLS vegetal BLASTOMERES ionophore INDUCTION
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A New Type of Dibenzoyl Tartaric Acid Selective Electrode Based on Polymer Membrane Containing Calixarene Ionophore 被引量:1
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作者 Meng L ing\|zhi, Mei Gong\|xiong, He Yong\|bing, Li Jiang\|feng (College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, Hubei, China) 《Wuhan University Journal of Natural Sciences》 CAS 2003年第01A期113-116,共4页
A new type of di benzoyl tartaric acid selective electr ode has been developed. Three double\| arm calixarene derivatives were emp loyed as the neutral ionophores. The poly(vinyl chloride) me... A new type of di benzoyl tartaric acid selective electr ode has been developed. Three double\| arm calixarene derivatives were emp loyed as the neutral ionophores. The poly(vinyl chloride) membrane electrode containing an amide derivative of ca lixarene as the neutral carrier an d a dibutyl phthalate as the plastici zer exhibited the highest sensitivity for dibenzoyl tartaric acid. The slop e of linear portion was 27.8 mV per c oncertration decade. The electrode has a fast response and a long lifetime . 展开更多
关键词 ion\|selective electrode calixarene ionophore mole cular recognition dibenzoyl tartaric acid
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Thiocyanate Ion Selective Solid Contact Electrode Based on Mn Complex of N,N'-BIs-(4-Phenylazosalicylidene)-O-Phenylene Diamine Ionophore 被引量:1
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作者 Won-Sik Han Tae-Kee Hong Young-Hoon Lee 《American Journal of Analytical Chemistry》 2011年第6期731-738,共8页
A thiocyanate ion selective poly(aniline) solid contact electrode based on manganese complex of N,N’-bis-(4-phenylazosalicylidene)-o-phenylene diamine ionophore was successfully developed. The electrode exhibits a go... A thiocyanate ion selective poly(aniline) solid contact electrode based on manganese complex of N,N’-bis-(4-phenylazosalicylidene)-o-phenylene diamine ionophore was successfully developed. The electrode exhibits a good linear response of 58.1 mV/decade (at 20?C ± 0.2?C, r2 = 0.998) with in the concentration range of 1 × 10–1.0 ~ 1 × 10–5.8 M thiocyanate solution. The composition of this electrode was: ionophore 0.040, polyvinylchloride 0.300, dibutylphthalate 0.660 (mass). This dibutylphthalate plasticizer provides the best response characteristics. The electrode shows good selectivity for thiocyanate ion in comparison with any other anions and is suitable for use with aqueous solutions of pH 4.0 ~ 6.0. The standard deviations of the measured emf difference were ±1.70 and ±2.01 mV for thiocyanate sample solutions of 1.0 × 10–2 M and 1.0 × 10–3 M, respectively. The stabilization time was less than 170 sec. and response time was less than 17 sec. 展开更多
关键词 THIOCYANATE ION SCEs ISEs MN Complexed ionophore Schiff Base ION Sensor
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Effect of Calcium Ionophore and Calcium Channel Blockers on Immediate Hypersensitivity Reactions
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作者 黄钦田 陈丙莺 孙爱民 《The Journal of Biomedical Research》 CAS 1994年第1期26-28,共3页
The release of mediators from mast cells is a model for cell secretion and is an in-vitro index for immediate hypersensitivity reactions. Calcium influx is generally accepted to be the primary biochemicalevent in mast... The release of mediators from mast cells is a model for cell secretion and is an in-vitro index for immediate hypersensitivity reactions. Calcium influx is generally accepted to be the primary biochemicalevent in mast cell activation.We studied the effect of the calcium ionophore A 23187 and calcium channelblockers,nifedipine and verapamil, in triggering the activation of rat peritoneal mast cells.At suitableconcentration nifedipine and verapamil have had the inhibition effect in the IgE-dependent roaction. 展开更多
关键词 calcium ionophore A23187 calcium channel blocker NIFEDIPINE VERAPAMIL mediator Histamine
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Solid-Contact Perchlorate Sensor with Nanomolar Detection Limit Based on Cobalt Phthalocyanine Ionophores Covalently Attached to Polyacrylamide
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作者 Mohammad Nooredeen Abbas Abdel Lattief A. Radwan +1 位作者 Philippe Bühlmann Mahmud A. Abd El Ghaffar 《American Journal of Analytical Chemistry》 2011年第7期820-831,共12页
Novel solid-contact perchlorate sensors based on cobalt phthalocyanine-C-monocarboxylic acid (I), and cobalt phthalocyanine-C,C,C,C-tetracarboxylic acid (II) as free ionophores and covalently attached to polyacryla- m... Novel solid-contact perchlorate sensors based on cobalt phthalocyanine-C-monocarboxylic acid (I), and cobalt phthalocyanine-C,C,C,C-tetracarboxylic acid (II) as free ionophores and covalently attached to polyacryla- mide (PAA)—ionophores III and IV, respectively were prepared. The all solid-state sensors were constructed by the application of a thin film of a polymer cocktail containing a phthalocyanine ionophore and cetyltrimethylammonium bromide (CTMAB) as a lipophilic cationic additive onto a gold electrode precoated with the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) as an ion and electron transducer. The sensor with 10.3% of ionophore (III) covalently attached to plasticizer-free poly (butyl methacrylate-co-do- decyl methacrylate) (PBDA) exhibited a good selectivity for perchlorate and discriminated many ions, in- cluding F–, Cl–, Br–, I–, SCN–, , S2– and . The covalent attachment of the ionophore to the polymer resulted in a near-Nernstian anionic slope of –62.3 mV/decade whereas a super-Nernstian slope of –79.9 mV/ decade was obtained for the free ionophore. The sensor covered a linear concentration range of 5 × 10–9 - 1 × 10–2 mol?L–1 with a lower detection limit (LDL) of 1 × 10–9 mol?L–1 and gave a stable response over a pH range of 4 - 10.5. The all-solid state sensors were utilized for the selective flow injection potentiometric determination of perchlorate in natural water and human urine samples in the nanomolar concentration range. 展开更多
关键词 Ion-Selective Electrode SOLID CONTACT Covalent ionophore Attachment PERCHLORATE FLOW-INJECTION Analysis Urine
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Is There Any Role for Calcium Ionophore in ICSI Cycles for Cases of Non Obstructive Azoospermia?
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作者 Mohamed Elmahdy Yasser Oreif +1 位作者 Soad Musleh Emadeldin Khalifa 《Open Journal of Obstetrics and Gynecology》 2021年第8期1037-1049,共13页
<strong>Objectives:</strong><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> Evaluate the effect of ... <strong>Objectives:</strong><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> Evaluate the effect of artificial oocyte activation (AOA) using calcium ionophore (A23187) on the rate of fertilization and cleavage of embryos in surgically retrieved sperm of patients with non-obstructive azoospermia undergoing intracytoplasmic sperm injection (ICSI).</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style="font-family:Verdana;">Study design: </span></b></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">This study was conducted on 60 infertile couples undergoing ICSI cycles as a randomized controlled parallel group’s experimental study in a private IVF center in Egypt from January 2018 to July 2019. ICSI cycles were divided into two g</span><span style="font-family:Verdana;">roups: Group A: includes 30 ICSI patients with surgically retrieved sperms of non-obstructive azoospermia treated with calcium ionophore (A23187). Group C/Control: includes 30 ICSI patients with surgically retrieved sperms of non-obstructive azoospermia non-treated with calcium ionophore (A23187)</span><span style="font-family:Verdana;">. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">There was no statistical difference between both groups regarding the fertilization rate (</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> = 0.853). There was no statistical difference between them regarding implantation rate (</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> = 0.237). The percentage of Class A embryos in the ca ionophore group was 81.7%, while it was 82.8% in the control group. There was insignificant difference between them (</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> = 0.782). There was no statistical significant difference between the two groups regarding the clinical pregnancy rate</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> it was (56.7%) in the ca ionophore group while it was (53.3%) in the control group.</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style="font-family:Verdana;">Conclusion: </span></b></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">AOA by Ca</span><sup><span style="font-family:Verdana;">2++</span></sup></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ionophore didn’t improve the outcome of ICSI cycle in cases of non obstructive azoospermia in terms of fertilization, implantation and pregnancy rate.</span></span></span> 展开更多
关键词 Fertilization Failure ICSI Azosperemia Ca ionophore
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Revealing the kinetics of ionophore facilitating ion transport across lipid bilayers by surface enhanced infrared absorption spectroscopy
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作者 Qianwen Zhang Yang Liu +1 位作者 Jian Li Xinghua Xia 《Chinese Chemical Letters》 SCIE CAS CSCD 2020年第2期479-481,共3页
Ionophore can prominently improve the ion permeability of cell membrane and disrupt cellular ion homeostasis.Most studies regarding ionophore facilitating ion transmembrane transport focus on artificial liquid-liquid ... Ionophore can prominently improve the ion permeability of cell membrane and disrupt cellular ion homeostasis.Most studies regarding ionophore facilitating ion transmembrane transport focus on artificial liquid-liquid interfaces,which have large difference from the actual environment of cell membrane.Here,we construct a supported lipid bilayeron a gold nanoparticles film modified ZnSe prism as an appropriate model of cell membrane to investigate the dynamic of the ion transport facilitated by ionophore using surface enhanced infrared absorption spectroscopy(SEIRAS).We find that the ion transmembrane transport consists of two steps:The ion transmembrane transport starts with the association/disassociation between ion and ionophore at the edge of lipid bilayer;The second step is the transfer of ion-ionophore complex across lipid bilayer.Our results show that the complex transfer across the lipid bilayer is the rate determining step. 展开更多
关键词 SEIRAS Ion TRANSMEMBRANE transport ionophore KINETICS Supported LIPID BILAYERS
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熊射出精子体外获能的研究
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作者 张嘉保 于仙忠 +1 位作者 武世珍 刘光泽 《草食家畜》 1992年第S1期100-102,共3页
本文报道了用咖啡因和Ionophore A23187(Ⅰ-A)诱导熊射出精子体外获能的研究。用去透明带仓鼠卵穿透试验评价获能效果,用台盼兰—姬姆萨(TG)染色检测精子的死活及顶体形态。结果发现,咖啡因与Ⅰ-A能诱导熊精子体外获能,经获能处理的精... 本文报道了用咖啡因和Ionophore A23187(Ⅰ-A)诱导熊射出精子体外获能的研究。用去透明带仓鼠卵穿透试验评价获能效果,用台盼兰—姬姆萨(TG)染色检测精子的死活及顶体形态。结果发现,咖啡因与Ⅰ-A能诱导熊精子体外获能,经获能处理的精子能穿入卵内,穿透率达70%以上,并能形成发育良好的雄原核。咖啡因与Ⅰ-A能在体外诱导熊精子的顶体反应,相关分析表明,有顶体反应活精子百分率与穿透率呈强正相关(r=0.94,n=6,P<0.01)。TG染色是检测精子顶体反应的有效手段,并能预测获能处理后精子的受精能力。 展开更多
关键词 熊射出精子 体外获能 顶体反应 咖啡因 ionophore A23187
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PVC Membrane Selective Electrode for Determination of Cadmium(Ⅱ) Ion in Chocolate Samples 被引量:2
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作者 Sulekh Chandra Deepshikha Singh Anjana Sarkar 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第4期480-488,共9页
Benzil bis(carbohydrazone)(BBC) is prepared and explored as new N N Schiff's base, which plays the role of an excellent ion carrier in the construction of a Cd(II) ion membrane sensor. The tris(2-ethylhexyl) phosp... Benzil bis(carbohydrazone)(BBC) is prepared and explored as new N N Schiff's base, which plays the role of an excellent ion carrier in the construction of a Cd(II) ion membrane sensor. The tris(2-ethylhexyl) phosphate best performance corresponds to a membrane composition of 30% poly(vinyl chloride), 65%(TEHP), 3.5% BBC and 1.5% tetradodecyl-ammoniumtetrakis(4-chlorophenyl) borate(ETH 500). This sensor shows very good selectivity and sensitivity towards cadmium ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The effect of membrane composition, selectivity, pH and influence of additive on the response properties of electrode were investigated. The response mechanism was discussed in the view of UV-spectroscopy. The electrode exhibits a Nernstian behavior(with slope of 29.7 mV per decade) over a very wide concentration range from 1.0×10?1 to 1.0×10?8 mol·L?1 with a detection limit of 3.2×10?8 mol·L?1. It shows rela-tively fast response time in whole concentration range(<8 s) and can be used for at least 10 weeks in the pH range of 2.0-9.0. The proposed sensor is successfully used for the determination of cadmium in different chocolate sam-ples and as indicator electrode in titration with ethylene diamine tetraacetate(EDTA). 展开更多
关键词 benzil bis(carbohydrazone) ionophore Cd(II) ion membrane sensor selectivity coefficient additive
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Correlation between inhibition of calcium-dependent apoptosis by cyclosporin A and calcium transportation in HL-60 cells 被引量:1
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作者 HUANG QI QING MING FANG +1 位作者 HONG QING ZHANG SHAO BAI XUE(Department of Biology, Beijing Normal University, Beijing 100875, China.) 《Cell Research》 SCIE CAS CSCD 1996年第1期23-30,共8页
Both calcium ionophore A23187 and endoplasmic reticulum Ca2+- ATPase inhibitor thapsigargin (Tg) could increase intracellular free calcium concentration and induce apoptosis in some cell lines. In the present study, w... Both calcium ionophore A23187 and endoplasmic reticulum Ca2+- ATPase inhibitor thapsigargin (Tg) could increase intracellular free calcium concentration and induce apoptosis in some cell lines. In the present study, we found that HL-60 cells treated with A23187 (1μg/ml) for 4 h or with Tg (0.5μg/ml) for 2 h showed typical characteristics of apoptosis. Pretreatment with nontoxic concentration of cyclosporin A (CsA) (1μg/ml) Could block these effects. Flow cytometric analysis of intracellular Ca2+ after staining with fluo-3 AM showed that CsA did not prevent the increase of intracellular calcium induced by A23187 or Tg, but it could maintain the high level of intracellular Ca2+ for a long time. These results suggest that CsA may prevent calcium- induced apoptosis by blocking the transportation of Ca2+ in HL-60cells. 展开更多
关键词 Cyclosporin A calcium ionophore A_(23187) THAPSIGARGIN APOPTOSIS intracellular calcium
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Study of Non-Ideal Effects for Extended Gate Field Effect Transistor Chlorine Ion Sensing Device 被引量:1
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作者 Jung-Chuan Chou Pei-Lan Chou 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2006年第A03期242-243,共2页
We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then ... We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then the chlorine ion selective membrane is formed on the sensing window,and the fabrication of the EGFET chlorine ion sensing device is completed.The surface potential on the sensing membrane of the EGFET chlorine ion sensing device will be changed in the different chlorine ion concentration solutions,then changes further gate voltage and drain current to detect chlorine ion concentration.We will study non-ideal effects such as temperature,hysteresis and drift effects for the EGFET chlorine ion sensing device in this paper,these researches will help us to improve the sensing characteristics of the EGFET chlorine ion sensing device. 展开更多
关键词 extended gate field effect transistor chlorine ion ionophore chlorine ion sensing device temperature effect hysteresis effect drift effect
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Chemically Modified Carbon Paste Electrode for Determination of Cesium Ion by Potentiometric Method 被引量:2
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作者 Refat F. Aglan Gehad G. Mohamed Hala A. Mohamed 《American Journal of Analytical Chemistry》 2012年第8期576-586,共11页
A new chemically modified carbon paste electrode for cesium(I) ion determination based on potassium zinc hexacyan-oferrate (PZHCF) as an ionophore was prepared. The electrode exhibits a Nernstian response for Cs(I) io... A new chemically modified carbon paste electrode for cesium(I) ion determination based on potassium zinc hexacyan-oferrate (PZHCF) as an ionophore was prepared. The electrode exhibits a Nernstian response for Cs(I) ions over a wide concentration range from 1 × 10-6 to 1 × 10-1 mol·L-1 with a slope of 58 ± 0.5 mV·decade-1. It has a response time of about 35 s and can be used for a period of 3 months with good reproducibility. Detection limit obtained in the optimal conditions was 3 × 10-7 mol·L-1. The potentiometric response is independent of the pH of the solution in the pH range 4.0 - 8.0. The electrode possesses the advantages of low resistance, fast response over a variety of other cations. The proposed electrode is applied as a sensor for the determination of Cs(I) ion concentration in different samples solutions. The results showed a good correlation with the data obtained by atomic absorption spectrometric method. 展开更多
关键词 CESIUM DETERMINATION Modified Ion Selective Electrode POTASSIUM ZINC HEXACYANOFERRATE ionophore
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LINEAR POLYSILOXANE WITH DIBENZO-18-CROWN-6 MOIETIES AS LIQUID MEMBRANE CARRIER
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作者 龚淑玲 卢雪然 +1 位作者 卢先明 陈远荫 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1995年第2期173-179,共7页
A modified method of preparing crown functionalized linear polysiloxane has been described. 4'-Allyldibenzo-18-crown-6 was subjected to hydrosilylation with methyldichlorosilane, followed by polycondensation with ... A modified method of preparing crown functionalized linear polysiloxane has been described. 4'-Allyldibenzo-18-crown-6 was subjected to hydrosilylation with methyldichlorosilane, followed by polycondensation with silanol-terminated polydimethylsiloxane to give the title crown functionalized linear polysiloxane. The transport properties of sodium, potassium, and ammonium salt through a bulk liquid membrane system using the new type of crown functionalized linear polysiloxane as a carrier were investigated. It is worthy to point out that the carrier can be used repeatedly at least six runs with no apparent change in the transport rate of potassium ion. 展开更多
关键词 LIQUID MEMBRANE CROWN ETHER POLYSILOXANE ION TRANSPORT ionophore
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APOPTOSIS INDUCED BY HYPERTHERMIA IN HUMAN GLIOBLASTOMA CELL LINE AND MURINE GLIOBLASTOMA
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作者 浦佩玉 张亚卓 江德华 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 2000年第4期257-262,共6页
Objective: To study the role of apoptosis in tumor cell of malignant glioma death following treatment with hyperthermia and calcium ionophore. Methods: The apoptosis induced by hyperthermia and calcium ionophore, A231... Objective: To study the role of apoptosis in tumor cell of malignant glioma death following treatment with hyperthermia and calcium ionophore. Methods: The apoptosis induced by hyperthermia and calcium ionophore, A23187, in human glioblastoma cell line TJ905 and murine glioblastoma G422 was evaluated by characteristic findings in DNA agarose gel electrophresis, ultrastructural examination and flow cytometric analysis. Results: Apoptosis could be induced by moderate hyperthermia, but not by mild hyperthermia, calcium ionophore enhanced significantly the effect of mild hyperthermia on the induction of apoptosis. Conclusion: This result indicates that apoptotic cell death is one of the mechanisms of hyperthermic therapy for malignant glioma and taking measures to increase the cytolic calcium may enhance the effect of hyperthermia. 展开更多
关键词 APOPTOSIS HYPERTHERMIA Calcium ionophore GLIOBLASTOMA
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Synthesis of N-(2-Hydroxy-1-Phenoxyacetyl)Prolyproline
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作者 Yang Dingqiao(Department of Chemistry,Huanggang Teachers College, Huanggang City, Hubei 436100,China)Grace B Borowitz,Irving J Borowitz(Department of Chemistry,Ramapo College of New Jersey, Mahwah,NJ 07430,USA) 《Wuhan University Journal of Natural Sciences》 EI CAS 1998年第2期217-220,共4页
Ionophores consist of molecules which surround and carry positive metal ions and other ions through biological membranes. One classe of ionophores which we have been developing contains dipeptides which are encouraged... Ionophores consist of molecules which surround and carry positive metal ions and other ions through biological membranes. One classe of ionophores which we have been developing contains dipeptides which are encouraged to become part of a ring because of possible hydrogen bond formation between the 2-hydroxy on the phenyl group and carboxyl group (COOH) of the final amide proline. Formation of a ring should increase the complexation ability of the ionophore. We report that the synthesis of N-(2-hydroxyl-1-phenoxyacetyl) prolyproline(1), a novel ionophore is prepared from activated 2-acetoxy phenoxyacetic acid (3a) and the appropriate dipeptide ester using coupling methods such as dicyclohexyl carbodiimide with hydroxyben-ztriazole or carbonyl diimidazole. 展开更多
关键词 SYNTHESIS ionophore DIPEPTIDE
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Finishing Cattle in All-Natural and Conventional Production Systems
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作者 Zachary K. Smith Peter T. Anderson Bradley J. Johnson 《Open Journal of Animal Sciences》 2020年第2期237-253,共17页
Beef cattle producers in the North America have a variety of production and marketing options and must choose the best production system for their situation. This review describes considerations involved in choosing b... Beef cattle producers in the North America have a variety of production and marketing options and must choose the best production system for their situation. This review describes considerations involved in choosing between feeding cattle conventionally versus feeding them in programs that prohibit the use of certain technologies. Data from peer-reviewed journals, extension publications, nutritional consultants, governmental organizations, and feed companies were used to construct this review. Most cattle in North America are fed in conventional production systems. Conventional beef production systems typically use steroidal implants, ionophores, and beta-adrenergic agonists to improve animal productivity;as well as feed grade and injectable antimicrobials to control, treat or prevent disease and improve animal health. These technologies have been shown to lower the cost of production, allowing for beef to be competitive in the global protein market. Some consumers have expressed a preference for beef produced without these technologies. These “All-natural” (AN) cattle may bring a premium price in the market. The economic impact of differing productions systems can be described in relation to 1) cost of production, 2) operating costs of the feedlot, 3) price paid for feeder calves, and 4) price received for fed cattle. Conventional production provides the most favorable outcome for factors 1, 2, and 3, while AN production provides the most favorable outcome for item 4. There are also industry wide and societal aspects related to differing beef production systems related to health and safety of beef, land use, and cost of production allowing for a greater share of the global protein market. Technologies used in conventional production are critical tools to North American beef production. Differences in efficiencies between each type of non-conventional production systems must be re-captured in added premiums when cattle are marketed and sold. Premiums for AN cattle are enticing, but the true differences in the cost of production between the AN and conventional cattle must be evaluated in order for a producer to make the correct decision for their operation. 展开更多
关键词 All-Natural Beef Beta-Adrenergic AGONIST CONVENTIONAL ionophore
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The Relationship between Some lons and Acrosome Reaction of Human Sperm
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作者 王春年 谢文英 +1 位作者 徐胜 王一飞 《Journal of Reproduction and Contraception》 CAS 1994年第1期204-208,共5页
The acrosome reaction of sperm was induced by calcium ionophore A 23187.The letionship between some ions and acrosome reaction by removing Na+ from the medium.or by adding angtagonist of K+.TEA chloride,or antagonist ... The acrosome reaction of sperm was induced by calcium ionophore A 23187.The letionship between some ions and acrosome reaction by removing Na+ from the medium.or by adding angtagonist of K+.TEA chloride,or antagonist of Ca++,verapamil,or anlagonist of Na+-K+-ATPase,acetyl strophanthithidin is studied.The results show that Na+,H,Ca++ and Na+ pump are necessary.for acrosome reaclion of human sperm.The Ca++ might not enter the sperms through the channel of Ca++. 展开更多
关键词 Acrosome reaction ionophore IONS
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Preparation and Properties of a New Carbon Paste Iron Selective Electrodes and Their Applications
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作者 Refat F. Aglan Mahmoud S. Rizk +2 位作者 Gehad G. Mohamed Ahmed H. El-Wahy Hala A. Mohamed 《American Journal of Analytical Chemistry》 2014年第2期140-148,共9页
The new ferrous-selective modified carbon paste electrodes (I and II) based on 5,5’-(propane-1,3-diylbis(sulfanediyl))bis(3-benzyl-4H-1,2,4-triazol-4-amine) (electrode I, A-ionophore) and 5,5’-(butane-1,4-diyl-bis(s... The new ferrous-selective modified carbon paste electrodes (I and II) based on 5,5’-(propane-1,3-diylbis(sulfanediyl))bis(3-benzyl-4H-1,2,4-triazol-4-amine) (electrode I, A-ionophore) and 5,5’-(butane-1,4-diyl-bis(sulfane- diyl))bis(3-benzyl-4H-1,2,4-triazol-4-amine) (electrode II, B-ionophore) as ionophores are described. These electrodes exhibit Nernstian slopes of 30.2 ± 0.5 and 29.1 ± 0.5 mV·decade-1, linear range of 1.0 × 10-7 - 1.0 × 10-2 mol·L-1 Fe(II) ion and detection limit of 1.0 × 10-7 mol·L-1 Fe(II) ion for electrode (I) and electrode (II), respectively. Both electrodes (I and II) have a fast response time of about 15 sand can be used for at least 3 months. The two electrodes revealed a good selectivity for Fe(II) over a wide variety of other metal ions and could be used in the pH range of 1.8 - 3.0 without any divergence in potential. The proposed sensors were successfully applied for the determination of Fe(II) ion in different real samples. 展开更多
关键词 Triazol ionophoreS FERROUS Ion Determination Modified CARBON PASTE ELECTRODES
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放线菌C-411发酵液抑菌活性及活性成分 被引量:11
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作者 赵娜 王海丽 +2 位作者 魏少鹏 姬志勤 吴文君 《植物保护学报》 CAS CSCD 北大核心 2013年第1期73-77,共5页
为了明确放线菌C-411发酵液中的抑菌活性成分和评价其在农林病害防治中的潜在应用价值,采用抑菌活性追踪法,经大孔树脂吸附、硅胶柱层析及反相高效液相色谱等方法,从C-411菌株发酵液中分离得到1个抑菌活性化合物Za-1,经ESI-MS、NMR等波... 为了明确放线菌C-411发酵液中的抑菌活性成分和评价其在农林病害防治中的潜在应用价值,采用抑菌活性追踪法,经大孔树脂吸附、硅胶柱层析及反相高效液相色谱等方法,从C-411菌株发酵液中分离得到1个抑菌活性化合物Za-1,经ESI-MS、NMR等波谱技术鉴定为聚醚类抗生素ionophore X-206。Za-1对枯草芽胞杆菌Bacillus subtilis、蜡状芽胞杆菌Bacillus cereus、金黄色葡萄球菌Staphyloccocus aureuse和猕猴桃溃疡病菌Pseudomonas syingae有强烈的抑制作用,其最小抑菌浓度分别为0.78、1.56、3.13和6.25μg/mL。Za-1对茄子黄萎病菌Verticillium dahliae、核果炭疽病菌Drupe anthrax和苹果炭疽病菌Colletotrichum gloeosporioides菌丝生长亦有明显的抑制作用,其抑制率分别为85.10%、87.66%和88.99%。研究表明化合物Za-1有开发成农用杀菌剂的潜力。 展开更多
关键词 放线菌C-411菌株 聚醚类抗生素 ionophore X-206 抑菌活性
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