Chloroquine blocks the Kir4.1 channels by an open-pore blocking mechanism

2017 ◽  
Vol 800 ◽  
pp. 40-47 ◽  
Author(s):  
Leticia G. Marmolejo-Murillo ◽  
Iván A. Aréchiga-Figueroa ◽  
Eloy G. Moreno-Galindo ◽  
Ricardo A. Navarro-Polanco ◽  
Aldo A. Rodríguez-Menchaca ◽  
...  
Keyword(s):  
Pore Blocking ◽  
Blocking Mechanism

A new approach to model asphaltene induced permeability damage with emphasis on pore blocking mechanism

2020 ◽  
Vol 184 ◽  
pp. 106512 ◽  
Author(s):  
Marzieh Ghadimi ◽  
Mojtaba Ghaedi ◽  
Mohammad R. Malayeri ◽  
Mohammad J. Amani
Keyword(s):  
New Approach ◽  
Pore Blocking ◽  
Permeability Damage ◽  
Blocking Mechanism

scholarly journals Mechanism of single- and double-sided inhibition of dual topology fluoride channels by synthetic monobodies

2017 ◽  
Vol 149 (4) ◽  
pp. 511-522 ◽  
Author(s):  
Daniel L. Turman ◽  
Randy B. Stockbridge
Keyword(s):  
Lipid Bilayers ◽  
Symmetry Axis ◽  
Voltage Dependence ◽  
Electrophysiological Study ◽  
Side Chain ◽  
Negative Cooperativity ◽  
Pore Blocking ◽  
Axis Parallel ◽  
Twofold Symmetry Axis ◽  
Blocking Mechanism

The Fluc family of proteins comprises small, electrodiffusive fluoride channels, which prevent accumulation of toxic F− ions in microorganisms. Recent crystal structures have confirmed their unusual architecture, in which a pair of antiparallel subunits convenes to form a dimer with a twofold symmetry axis parallel to the plane of the membrane. These structures have also revealed the interactions between Fluc channels and several different fibronectin domain monobodies that inhibit Fluc-mediated F− currents; in all structures, each channel binds to two monobodies symmetrically, one on either side of the membrane. However, these structures do not reveal the mechanism of monobody inhibition. Moreover, the results appear to diverge from a recent electrophysiological study indicating that monobody binding is negatively cooperative; that is, a bound monobody on one side of a Fluc channel decreases the affinity of an oppositely bound monobody by ∼10-fold. In this study, we reconcile these observations by probing the mechanism of monobody binding and its negative cooperativity using electrophysiological experiments in planar lipid bilayers. Our results indicate that monobody inhibition occurs via a pore-blocking mechanism and that negative cooperativity arises from electrostatic repulsion between the oppositely bound monobodies. A single glutamate residue, on a loop of the monobody that extends into the channel interior, is responsible for negatively cooperative binding. This glutamate side chain also confers voltage dependence and sensitivity to the concentration of trans-F− ion to monobody binding. Neutralization by mutation to glutamine abolishes these electrostatic effects. Monobodies that are amenable to cocrystallization with Fluc channels lack an analogous negatively charged side chain and bind independently to opposite sides of the channel. Thus, this work reveals the source of voltage dependence and negative cooperativity of monobody binding to Fluc channels along with the pore-blocking mechanism.

scholarly journals A novel N-terminal motif of dipeptidyl peptidase-like proteins inactivates KV4.2 channels by a pore-blocking mechanism

Channels ◽  
2009 ◽  
Vol 3 (6) ◽  
pp. 448-461 ◽  
Author(s):  
Henry H. Jerng ◽  
Kevin Dougherty ◽  
Manuel Covarrubias ◽  
Paul J. Pfaffinger
Keyword(s):  
Dipeptidyl Peptidase ◽  
Pore Blocking ◽  
Blocking Mechanism

Studies on pore blocking mechanism and technical feasibility of a hybrid PAC-MF process for reclamation of irrigation water from biotreated POME

2016 ◽  
Vol 51 (12) ◽  
pp. 2047-2061 ◽  
Author(s):  
Mutiu Kolade Amosa ◽  
Mohammed Saedi Jami ◽  
Ma’an Fahmi R. Alkhatib ◽  
Thokozani Majozi
Keyword(s):  
Irrigation Water ◽  
Technical Feasibility ◽  
Pore Blocking ◽  
Blocking Mechanism

Emulsion flow which preparation excludes a presence of mechanical impurities

2012 ◽  
Vol 9 (2) ◽  
pp. 118-122
Author(s):  
A.A. Rakhimov
Keyword(s):  
Cell Size ◽  
First Case ◽  
A Cell ◽  
Emulsion Flow ◽  
Blocking Mechanism

Experiments were carried out with waterhydrocarbon emulsions with various emulsifiers in capillaries with a length of 2 cm, diameters of 40 and 100 µm. To eliminate the influence of mechanical impurities comparable in size with the diameter of the capillary in first case emulsion components were filtered through fine-meshed filters. In second case obtained that way emulsion was additionally filtered through a system consisting of 3 filters with a cell size of 30-40 microns. In a capillary of 100 µm such emulsion came in a blocked state. Additional filtration of the emulsion through the mesh filters have led to an increase in viscosity but in 100 µm capillaries the time until the blocking 2-3 times more than the original. Rheology of used emulsions is well described by the model of Ostwald-de Waale. It was determined that emulsion blocking mechanism is due to the presence of inclusions not emulsion viscosity.

scholarly journals Tanning Wastewater Treatment by Ultrafiltration: Process Efficiency and Fouling Behavior

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 461
Author(s):  
Fu Yang ◽  
Zhengkun Huang ◽  
Jun Huang ◽  
Chongde Wu ◽  
Rongqing Zhou ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Shear Rate ◽  
Membrane Surface ◽  
Filtration Efficiency ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Transmembrane Pressure ◽  
Leather Industry ◽  
Pore Blocking ◽  
The Impact

Ultrafiltration is a promising, environment-friendly alternative to the current physicochemical-based tannery wastewater treatment. In this work, ultrafiltration was employed to treat the tanning wastewater as an upstream process of the Zero Liquid Discharge (ZLD) system in the leather industry. The filtration efficiency and fouling behaviors were analyzed to assess the impact of membrane material and operating conditions (shear rate on the membrane surface and transmembrane pressure). The models of resistance-in-series, fouling propensity, and pore blocking were used to provide a comprehensive analysis of such a process. The results show that the process efficiency is strongly dependent on the operating conditions, while the membranes of either PES or PVDF showed similar filtration performance and fouling behavior. Reversible resistance was the main obstacle for such process. Cake formation was the main pore blocking mechanism during such process, which was independent on the operating conditions and membrane materials. The increase in shear rate significantly increased the steady-state permeation flux, thus, the filtration efficiency was improved, which resulted from both the reduction in reversible resistance and the slow-down of fouling layer accumulate rate. This is the first time that the fouling behaviors of tanning wastewater ultrafiltration were comprehensively evaluated, thus providing crucial guidance for further scientific investigation and industrial application.

scholarly journals Piroxicam Loading onto Mesoporous Silicas by Supercritical CO2 Impregnation

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2500
Author(s):  
Marta Gallo ◽  
Luca Serpella ◽  
Federica Leone ◽  
Luigi Manna ◽  
Mauro Banchero ◽  
...  
Keyword(s):  
Supercritical Co2 ◽  
Water Solubility ◽  
Solid Dispersions ◽  
Mesoporous Silicas ◽  
Incipient Wetness Impregnation ◽  
Pore Blocking ◽  
Physico Chemical ◽  
Adsorption From Solution ◽  
First Time ◽  
Loading Procedure

Piroxicam (PRX) is a commonly prescribed nonsteroidal anti-inflammatory drug. Its efficacy, however, is partially limited by its low water solubility. In recent years, different studies have tackled this problem and have suggested delivering PRX through solid dispersions. All these strategies, however, involve the use of potentially harmful solvents for the loading procedure. Since piroxicam is soluble in supercritical CO2 (scCO2), the present study aims, for the first time, to adsorb PRX onto mesoporous silica using scCO2, which is known to be a safer and greener technique compared to the organic solvent-based ones. For comparison, PRX is also loaded by adsorption from solution and incipient wetness impregnation using ethanol as solvent. Two different commercial mesoporous silicas are used (SBA-15 and Grace Syloid® XDP), which differ in porosity order and surface silanol population. Physico-chemical analyses show that the most promising results are obtained through scCO2, which yields the amorphization of PRX, whereas some crystallization occurs in the case of adsorption from solution and IWI. The highest loading of PRX by scCO2 is obtained in SBA-15 (15 wt.%), where molecule distribution appears homogeneous, with very limited pore blocking.

scholarly journals Fouling layer characterization and pore-blocking mechanisms in an UF membrane externally coupled to a UASB reactor

Water SA ◽  
2017 ◽  
Vol 43 (4) ◽  
pp. 573 ◽  
Author(s):  
Mónica L Salazar-Peláez ◽  
Juan Manuel Morgan-Sagastume ◽  
Adalberto Noyola
Keyword(s):  
Uasb Reactor ◽  
Pore Blocking ◽  
Blocking Mechanisms
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