Controlling the spontaneous spiking regularity via channel blocking on Newman-Watts networks of Hodgkin-Huxley neurons

We investigate the regularity of spontaneous spiking activity on Newman-Watts small-world networks consisting of biophysically realistic Hodgkin-Huxley neurons with a tunable intensity of intrinsic noise and fraction of blocked voltage-gated sodium and potassium ion channels embedded in neuronal membranes. We show that there exists an optimal fraction of shortcut links between physically distant neurons, as well as an optimal intensity of intrinsic noise, which warrant an optimally ordered spontaneous spiking activity. This doubly coherence resonance-like phenomenon depends significantly, and can be controlled via the fraction of closed sodium and potassium ion channels, whereby the impacts can be understood via the analysis of the firing rate function as well as the deterministic system dynamics. Potential biological implications of our findings for information propagation across neural networks are also discussed.Comment: 6 two-column pages, 5 figures; accepted for publication in Europhysics Letter

Analysis of Potassium Ion (K+), Sodium Ion (Na+), and Proteins from Coconut Water Variety of Coconut and Hybrid Coconut

Analysis of potassium ion (K+), sodium ion (Na+), and proteins of Dalam coconut varieties water and Hybrid coconut varieties water have been done. The sample is green coconut which was taken simple random from Deli Tua Barat village in the regency of Deli Tua. Analysis of potassium ion (K+) and sodium ion (Na+) was determined by Atomic Absorption Spectrophotometry method (AAS) and analysis of protein was determined by the Kjeldahl method. From the result analysis of Dalam coconut varieties water contain amount potassium ion 321.60 mg/100 mL + 0,77 mg/100 mL, sodium ion 33.17 mg/100 mL + 1.85 mg/100 mL, and protein 0,18 % + 0.05 %. Whereas Hybrid coconut varieties water contain amount potassium ion 278.67 mg/100 mL + 1.53 mg/100 mL, sodium ion 31.33 mg/100 mL + 0.83 mg/100 mL, and protein 0.48 % + 0.3 %

»Programmable« Selective Inexpensive Potentiometric Detector for Flow Injection Analysis. Potassium Determination with a Nafion Membrane Modified Electrode

The study of a nafion membrane (ISE membrane) for the inexpensive potentiometric detection of potassium ion in a flow injection system is reported. The nafion membrane doped with potassium ion showed that excellent selectivity could be achieved for various cations, except for Rb+, and some interference for Cs+. A linear potential response of 10-2 - 10~® M for the potassium ion was obtained with a detection limit of about 0.5 x 10-6 M. This approach can be employed for constructing a potentiometric detector for virtually any cation (soluble at basic pH values) by simply changing the electrode pretreatment (or doping solution)

Development of potassium ion conducting hollow glass fibers

Potassium ion conducting glasses, chemically resistant to potassium, potassium sulfide and sulfur, were made and their possible utility as the membrane material for a potassium/sulfur battery was evaluated. At least one satisfactory candidate was found. It possesses an electrical resistance which makes it usable as a membrane in the form of a fine hollow fiber. It's chemical and electrochemical resistances are excellent. The other aspects of the possible potassium sulfur battery utilizing such fine hollow fibers, including the header (or tube sheet) and a cathode current collector were studied. Several cathode materials were found to be satisfactory. None of the tube sheet materials studied possessed all the desired properties. Multi-fiber cells had very limited life-time due to physical failure of fibers at the fiber/tube sheet junctions

The Effects of Changing Membrane Compositions and Internal Electrolytes on the Respon of Potassium Ion Sensor

A study on the changing of membrane compositions and internal solution towards the response potassium ion sensor was carried out. Potassium ion sensor based on photocured cross linking poly(n-butyl acrylate) membranes with varying composition of valinomycin (val), sodium tetrakis [3.5-bis(trifluoro-methyl) phenyl] borat (NaTFPB), types ion of internal solution were investigated. Effects of varying composition of val, NaTFPB, types and concentration of internal solution were observed on potassium ion sensor. The effect of higher val composition was lower LOD, wider linear range, lower sensitivity but increase selectivity. Higher NaTFPB compositions lead to lower LOD, higher sensitivity and selectivity. The effect of changing internal electrolyte lead to lower LOD, wider linear response range and higher selectivity according to internal electrolyte consisting Na+, Ca2+ and K+, and sensitivity increase following internal electrolyte with Ca2+, K+ and Na+

Sperm BerserKers

Human sperm cells rely on an unusual type of potassium ion channel

Determination of association constants between 5 '-guanosine monophosphate gel and aromatic compounds by capillary electrophoresis

Hydro gel formed by 5'-guanosine monophosphate (GMP) in the presence of a potassium ion is expected to exhibit interesting selectivity in capillary electrophoretic separations. Here, we estimated the conditional association constants between the hydro gel (G-gel) and aromatic compounds by capillary electrophoresis in order to investigate the separation selectivity that is induced by the G-gel. Several aromatic compounds were separated in a solution containing GMP and potassium ion at different concentrations. The association constants were calculated by correlating the electrophoretic mobilities of the analytes obtained experimentally using a concentration of G-gel. During semi-quantitative estimation, naphthalene derivatives had larger association constants (K-ass = 10.3-16.8) compared with those of benzene derivatives (K-ass = 3.91-5.31), which means that the binding sites of G-gel match better to a naphthalene ring than to a benzene ring. A hydrophobic interaction was also found when the association constants for alkyl resorcinol were compared with those of different hydrocarbon chains. The association constants of nucleobases and tryptophan ranged from 6.05 to 12.6, which approximated the intermediate values between benzene and naphthalene derivatives. Consequently, the selective interaction between G-gel and aromatic compounds was classified as one of three types: (1) an intercalation into stacked planar GMP tetramers; (2) a hydrophobic interaction with a long alkyl chain; or, (3) a small contribution of steric hindrance and/or hydrogen bonding with functional groups such as amino and hydroxyl groups

Self-assembly and potassium ion triggered disruption of peptide-based soft structures

This report describes formation of soft vesicular structures by a tetrapeptide and its disruption triggered by potassium ions