Slow kinetics of a potassium channel inAcetabularia

1988 ◽  
Vol 102 (2) ◽  
pp. 141-152 ◽  
Author(s):  
A. Bertl ◽  
H. G. Klieber ◽  
D. Gradmann
2014 ◽  
Vol 113 (3) ◽  
Author(s):  
E. Ben-Naim ◽  
P. L. Krapivsky
Keyword(s):  

2017 ◽  
Vol 112 (3) ◽  
pp. 172a-173a
Author(s):  
Laura S. Alberio ◽  
Giordano Defranceschi ◽  
Federica Simeoni ◽  
Paolo Zuccolini ◽  
Gerhard Thiel ◽  
...  

2015 ◽  
Vol 21 (3) ◽  
pp. 429-439 ◽  
Author(s):  
Marija Ilic ◽  
Franz-Hubert Haegel ◽  
Vesna Pavelkic ◽  
Snezana Zlatanovic ◽  
Zoran Markovic ◽  
...  

Microemulsion systems with water, toluene and nonionic surfactants are interesting for application due to the excellent solvent properties of aromatic hydrocarbons. In this study, the pseudo-binary phase diagram (?fish-diagram?) of such a ternary system was investigated using a branched technical alkyl polyethoxylate. Lutensol ON 50 (i-C10E5) was considered a suitable surfactant. The system with technical branched i-C10E5 exhibits very long and for compositions near optimum solubilization, i.e. the minimum content of surfactant needed for a bicontinuous microemulsion, extremely long times for equilibration. In addition to visual observation, qualitative measurements of turbidity were performed with a UV-Vis spectrometer for characterizing the behavior of this unusually sluggish system. Isothermal phase diagrams at 20, 25 and 30?C yielded inconsistent results after the change of temperature and the application of mechanical stress for different treatment of the samples. Ternary mixtures of water, toluene, and Lutensol ON 50 seem to form long-living metastable states. The sluggishness and the ambiguous phase behavior of the system are discussed. Inconsistent results are attributed to the slow kinetics of the formation and destruction of liquid crystals and the ability of the system to form miniemulsions within an unusual concentration range.


Author(s):  
junsheng lin ◽  
Yangcheng Mo ◽  
Shiwen Li ◽  
Jie Yu

Under high sulfur loading, high sulfur content and low electrolyte/sulfur ratio (E/S), the practical application of lithium sulfur (Li–S) batteries is seriously limited by the negative and slow kinetics of...


1999 ◽  
Vol 81 (4) ◽  
pp. 1974-1977 ◽  
Author(s):  
Daniel Dilks ◽  
Huai-Ping Ling ◽  
Mark Cockett ◽  
Patricia Sokol ◽  
Randy Numann

Cloning and expression of the human Kv4.3 potassium channel. We report on the cloning and expression of hKv4.3, a fast inactivating, transient, A-type potassium channel found in both heart and brain that is 91% homologous to the rat Kv4.3 channel. Two isoforms of hKv4.3 were cloned. One is full length (hKv4.3 long), and the other has a 19 amino acid deletion (hKv4.3 short). RT-PCR shows that the brain contains both forms of the channel RNA, whereas the heart predominantly has the longer version. Both versions of the channel were expressed in Xenopus oocytes, and both contain a significant window or noninactivating current seen near potentials of −30 to −40 mV. The inactivation curve for hKv4.3 short is shifted 10 mV positive relative to hKv4.3 long. This causes the peak window current for the short version to occur near −30 mV and the peak for the longer version to be at −40 mV. There was little difference in the recovery from inactivation or in the kinetics of inactivation between the two isoforms of the channel.


Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2106
Author(s):  
K. Karuppasamy ◽  
K. Prasanna ◽  
Vasanth Rajendiran Jothi ◽  
Dhanasekaran Vikraman ◽  
Sajjad Hussain ◽  
...  

A large volume of research on lithium–oxygen (Li–O2) batteries (LOBs) has been conducted in the recent decades, inspired by their high energy density and power density. However, these future generation energy-storage devices are still subject to technical limitations, including a squat round-trip efficiency and a deprived rate-capability, due to the slow-moving electrochemical kinetics of both the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) over the surface of the cathode catalyst. Because the electrochemistry of LOBs is rather complex, only a limited range of cathode catalysts has been employed in the past. To understand the catalytic mechanisms involved and improve overall cell performance, the development of new cathode electrocatalysts with enhanced round-trip efficiency is extremely important. In this context, transition metal carbides and nitrides (TMCs and TMNs, respectively) have been explored as potential catalysts to overcome the slow kinetics of electrochemical reactions. To provide an accessible and up-to-date summary for the research community, the present paper reviews the recent advancements of TMCs and TMNs and its applications as active electrocatalysts for LOBs. In particular, significant studies on the rational design of catalysts and the properties of TMC/TMN in LOBs are discussed, and the prospects and challenges facing the continued development of TMC/TMN electrocatalysts and strategies for attaining higher OER/ORR activity in LOBs are presented.


1997 ◽  
Vol 323 (1) ◽  
pp. 123-130 ◽  
Author(s):  
Ludwig MISSIAEN ◽  
Humbert DE SMEDT ◽  
Jan B. PARYS ◽  
Ilse SIENAERT ◽  
Henk SIPMA ◽  
...  

Inositol 1,4,5-trisphosphate (InsP3)-induced Ca2+ release from intracellular stores is generally assumed to be a ‘quantal’ process because low InsP3 concentrations mobilize less Ca2+ than high concentrations and a submaximal concentration does not release all the InsP3-mobilizable Ca2+. However, some recent reports questioned the generally accepted view that a low dose of InsP3 is unable to empty the whole store. We have now challenged the stores of permeabilized A7r5 cells in InsP3 for much longer periods than previously reported, to assess directly whether the slow phase of the release would empty the whole store (a non-quantal response) or only a fraction of it (a quantal response). Addition of a maximal [InsP3] at the end of a prolonged (92 min) stimulation with a submaximal [InsP3] resulted in additional Ca2+ release. Experiments in which the stores were challenged with different submaximal InsP3 concentrations for long time periods revealed that a lower [InsP3] never released the same amount of Ca2+ as a higher [InsP3]. This quantal pattern of Ca2+ release occurred both at 25 °C and at 4 °C. There was a time-dependent increase in the fraction of Ca2+ recruited by the lower compared with the higher [InsP3]. This recruitment of Ca2+ persisted if the [InsP3] was decreased, but was largely prevented by palmitoyl-CoA, a potent blocker of the luminal Ca2+ translocation between individual store units. ATP, in the presence of InsP3, released Ca2+ under conditions permitting the recruitment of no additional InsP3 receptors, indicating that an all-or-none emptying of a fraction of the stores cannot be the only mechanism responsible for quantal Ca2+ release in A7r5 cells. We conclude that some of the previously published evidence for a non-quantal Ca2+ release pattern should be reinterpreted.


2014 ◽  
Vol 85 (5) ◽  
pp. 769-776 ◽  
Author(s):  
Adam P. Hill ◽  
Mark J. Perrin ◽  
Juliane Heide ◽  
Terence J. Campbell ◽  
Stefan A. Mann ◽  
...  

2016 ◽  
Vol 7 (5) ◽  
pp. 3364-3369 ◽  
Author(s):  
Kenichi Shimizu ◽  
Lior Sepunaru ◽  
Richard G. Compton

A bifunctional fuel cell catalyst system demonstrated herein overcomes the slow kinetics of the oxygen reduction reaction by rapid heterogeneous disproportionation of hydrogen peroxide.


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