• Title/Summary/Keyword: Water Channels

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ESR Analysis of Cupric Ion Species Exchanged into NaH-ZSM-5 Gallosilicate

  • Yu, Jong-Sung;Kim, Jeong-Yeon
    • Journal of the Korean Magnetic Resonance Society
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    • v.5 no.1
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    • pp.1-12
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    • 2001

  • ZSM-5 gallosilicate molecular sieves was synthesized and cupric ion was ion-exchanged into the gallosilicate. The locations of Cu(ll) species in the framework and their interactions with various adsorbates were characterized by combined electron spin resonance(ESR) and electron spin echo modulation(ESEM) methods. It was found that in a fresh hydrated material, Cu(II) is octahedrally coordinated to six water molecules. This species is located in the channel intersections of two sinusoidal channels and rotates rapidly at room temperature. Evacuation removes some of these water molecules, leaving the Cu(II) coordinated to less water molecules and anchored to of oxygens in the channel wall. Dehydration produces two Cu(II) species, both of which are located in sites inaccessible to oxygen as evidenced by non-broadening of its ESR lines by oxygen. Adsorption of adsorbate molecules such as water, alcohols, ammonia, acetonitrile and ethylene on dehydrated CuNaH-ZSM-5 gallosilicate materials causes changes in the ESR spectrum of Cu(II), indicating the migration of Cu(II) into main channels to form complexes with these adsorbates there. Cu(II) forms a complex with two molecules of methanol, ethanol and propanol, respectively as evidenced by ESR parameters and ESEM data. Cu(II) also forms a square planar complex with four molecules of ammonia, based on the resolved nitrogen superhyperfine interactions and their ESEM parameters. Cu(II) forms a complex with two molecules of acetonitrile based on the ESR parameters and ESEM data. Interestingly, however, only part of Cu(II) interacts indirectly with one molecule of nonpolar ethylene based on ESR and ESEM analyses.

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A Study on the Design and Performance of a Prototype Pumping Skid for Resonant Frequency Control in the PEFP DTL (PEFP DTL 가속장치의 공진주파수 제어를 위한 펌프장치의 설계 및 성능에 관한 연구)

  • Kim, Kyung-Ryul;Park, Jun;Kim, Hyung-Gyun;Kim, Hee-Sub;Hwang, Woon-Ha;Yoon, Jong-Cheol;Lee, Mong-Su;Cho, En-Byul
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2064-2069
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    • 2008

  • The Resonance Control Cooling System (RCCS) prototype installed in KAERI site has been designed to control the resonant frequency of the normal conducting drift tube linac (DTL) for the Proton Engineering Frontier Project (PEFP). The RCCS water pumping skid is composed of two channels as a by-passing the cooling water and a plate heat exchanger. The required temperature can be achieved by mixing both channels in order to control its the resonant frequency at 350 MHz. The temperature controlled water pumping skid operates in combination with the Low Level Radio Frequency (LLRF) system. We have discussed the design, modeling with each components, control scheme, fabrication and test results of the water pumping skid for resonant frequency control of the DTL cavity. In conclusion, the fabricated RCCS prototype through the optimization of modeling has corresponded with the design requirement and concept.

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Patterns of Aquaporin 7 Expression in Normal Follicles and Follicular Cyst Follicles of Hanwoo (한우의 정상 난포와 난포낭종 난포에서 Aquaporin7 발현 양상)

  • Kim, Chang-Woon;Han, Sunkyu;Choe, Changyong
    • Journal of Embryo Transfer
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    • v.30 no.1
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    • pp.17-21
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    • 2015

  • Alteration in ion channel or transporter expression levels affects cell volume which is produced by movement of water and ion across the plasma membrane. In particular, aquaporin (AQP) channels among ion channels play a crucial role in movement of water across the cell membrane. This study was performed to identify whether AQP expression is changed in bovine follicular cystic follicles using microarray, RT-PCR and Western blotting analyses. In microarray data, AQP4 expression was decreased, whereas AQP7 was increased in cystic follicles. Additional experiments were focused on the AQP7 expression increased in cystic follicles. The microarray data was confirmed by semi-quantitative polymerase chain reaction (PCR) and Western blot analysis. AQP7 mRNA and protein expressions were significantly increased in the cystic follicles (p<0.05). Application of estrogen ($10{\mu}g/ml$) to bovine ovarian cells showed a trend of increase in AQP7 expression. From these results, we suggest that the increase in AQP7 expression in cystic follicles may play an important role in movement of water in bovine ovary. In addition, AQP7, a aquaglyceroporin permeating water and glycerol, could be a good target in development of methods for the cryopreservation of bovine ovary.

  • https://doi.org/10.12750/JET.2015.30.1.17 인용 PDF KSCI