Studies of the cation exchange system Fe+++−H+: II. Rate studies in concentrated solutions

AIChE Journal ◽  
1959 ◽  
Vol 5 (3) ◽  
pp. 394-396
Author(s):  
R. C. Vasishth ◽  
M. M. David
Keyword(s):  
Cation Exchange ◽  
Concentrated Solutions ◽  
Exchange System

Fractionation of rare earth elements within bone mineral: A natural cation exchange system

2011 ◽  
Vol 310 (1-2) ◽  
pp. 124-132 ◽  
Author(s):  
Clive N. Trueman ◽  
László Kocsis ◽  
Martin R. Palmer ◽  
Chris Dewdney
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Cation Exchange ◽  
Bone Mineral ◽  
Exchange System

scholarly journals Ionic Control of the Reversal Response of Cilia in Paramecium caudatum

1968 ◽  
Vol 51 (1) ◽  
pp. 85-103 ◽  
Author(s):  
Yutaka Naitoh
Keyword(s):  
Cation Exchange ◽  
Calcium Ions ◽  
Time Course ◽  
Calcium Release ◽  
Published Data ◽  
Paramecium Caudatum ◽  
Exchange System ◽  
Contractile System ◽  
Ciliary Reversal ◽  
Final Amount

The duration of ciliary reversal of Paramecium caudatum in response to changes in external ionic factors was determined with various ionic compositions of both equilibration and stimulation media. The reversal response was found to occur when calcium ions bound by an inferred cellular cation exchange system were liberated in exchange for externally applied cations other than calcium. Factors which affect the duration of the response were (a) initial amount of calcium bound by the cation exchange system, (b) final amount of calcium bound by the system after equilibration with the stimulation medium, and (c) concentration of calcium ions in the stimulation medium. An empirical equation is presented which relates the duration of the response to these three factors. On the basis of these and previously published data, the following hypothesis is proposed for the mechanism underlying ciliary reversal in response to cationic stimulation: Ca++ liberated from the cellular cation exchange system activates a contractile system which is energized by ATP. Contraction of this component results in the reversal of effective beat direction of cilia by a mechanism not yet understood. The duration of reversal in live paramecia is related to the time course of bound calcium release.

Studies of the cation exchange system Fe+++-H+: I. Equilibrium studies

AIChE Journal ◽  
1959 ◽  
Vol 5 (3) ◽  
pp. 391-393
Author(s):  
R. C. Vasishth ◽  
M. M. David
Keyword(s):  
Cation Exchange ◽  
Exchange System ◽  
Equilibrium Studies

scholarly journals 22Na+ fluxes in thymic lymphocytes. I. Na+/Na+ and Na+/H+ exchange through an amiloride-insensitive pathway.

1984 ◽  
Vol 84 (4) ◽  
pp. 565-584 ◽  
Author(s):  
S Grinstein ◽  
J D Goetz ◽  
A Rothstein
Keyword(s):  
Membrane Potential ◽  
Cation Exchange ◽  
Fluorescent Probes ◽  
Cytoplasmic Ph ◽  
Na Transport ◽  
Exchange System ◽  
Transport Pathways ◽  
Ion Substitution ◽  
Normal Rat ◽  
22Na Uptake

The Na+ transport pathways of normal rat thymocytes were investigated. Na+ conductance was found to be lower than K+ conductance, which is consistent with reported values of membrane potential. In contrast, the isotopically measured Na+ permeability was greater than 10-fold higher than that of K+, which indicates that most of the flux is electroneutral. Cotransport with Cl- (or K+ and Cl-) and countertransport with Ca2+ were ruled out by ion substitution experiments and use of inhibitors. Countertransport for Na+ or H+ through the amiloride-sensitive antiport accounts for only 15-20% of the resting influx. In the presence of amiloride, 22Na+ uptake was increased in Na+-loaded cells, which suggests the existence of Na+/Na+ countertransport. Cytoplasmic pH determinations using fluorescent probes indicated that under certain conditions this amiloride-resistant system will also exchange Na+ for H+, as evidenced by an internal Na+-dependent acidification is proportional to internal [Na+] but inversely related to extracellular [Na+]. Moreover, 22Na+ uptake is inhibited by increasing external [H+]. The results support the existence of a substantial amiloride-insensitive, electroneutral cation exchange system capable of transporting Na+ and H+.

Machine-Scored Syntax: Comparison of the CLAN Automatic Scoring Program to Manual Scoring

2020 ◽  
Vol 51 (2) ◽  
pp. 479-493
Author(s):  
Jenny A. Roberts ◽  
Evelyn P. Altenberg ◽  
Madison Hunter
Keyword(s):  
Data Exchange ◽  
Child Language ◽  
Exchange System ◽  
Absolute Point ◽  
Language Analysis ◽  
Search Patterns ◽  
Language Data ◽  
Report Accuracy ◽  
Point To Point ◽  
Automatic Scoring

Purpose The results of automatic machine scoring of the Index of Productive Syntax from the Computerized Language ANalysis (CLAN) tools of the Child Language Data Exchange System of TalkBank (MacWhinney, 2000) were compared to manual scoring to determine the accuracy of the machine-scored method. Method Twenty transcripts of 10 children from archival data of the Weismer Corpus from the Child Language Data Exchange System at 30 and 42 months were examined. Measures of absolute point difference and point-to-point accuracy were compared, as well as points erroneously given and missed. Two new measures for evaluating automatic scoring of the Index of Productive Syntax were introduced: Machine Item Accuracy (MIA) and Cascade Failure Rate— these measures further analyze points erroneously given and missed. Differences in total scores, subscale scores, and individual structures were also reported. Results Mean absolute point difference between machine and hand scoring was 3.65, point-to-point agreement was 72.6%, and MIA was 74.9%. There were large differences in subscales, with Noun Phrase and Verb Phrase subscales generally providing greater accuracy and agreement than Question/Negation and Sentence Structures subscales. There were significantly more erroneous than missed items in machine scoring, attributed to problems of mistagging of elements, imprecise search patterns, and other errors. Cascade failure resulted in an average of 4.65 points lost per transcript. Conclusions The CLAN program showed relatively inaccurate outcomes in comparison to manual scoring on both traditional and new measures of accuracy. Recommendations for improvement of the program include accounting for second exemplar violations and applying cascaded credit, among other suggestions. It was proposed that research on machine-scored syntax routinely report accuracy measures detailing erroneous and missed scores, including MIA, so that researchers and clinicians are aware of the limitations of a machine-scoring program. Supplemental Material https://doi.org/10.23641/asha.11984364

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