Voltammetry of drugs at the interface between two immiscible electrolyte solutions

2004 ◽  
Vol 76 (4) ◽  
pp. 697-705 ◽  
Author(s):  
Hailemichael Alemu
Keyword(s):  
Partition Coefficients ◽  
Electrolyte Solutions ◽  
Ionic Species ◽  
Precise Determination ◽  
Electrochemical Technique ◽  
New Approach ◽  
Charged Species ◽  
Two Phases ◽  
Ph Range

In this review, the results of the electrochemical investigations made on the transfer of ionizable drugs at the interface between two immiscible electrolyte solutions (ITIES) in the last decade have been presented. In many of the studies, cyclic voltammetry has been used to investigate the transfer characteristics of the charged species and deduce their partition coefficients, which are very important parameters to infer the lipophilicity of drugs in biological systems. The electrochemical technique allows the precise determination of the distribution of ionic species between two phases in a wider pH range. Such studies point out the complexity of the distribution of ionizable compounds and offer a new approach to relate the structure of such compounds to their passive transport across biological membranes.

Novel electrochemical fingerprinting methods for the precise determination of Ptshell coverage on Rucore nanoparticles

2014 ◽  
Vol 50 (78) ◽  
pp. 11558-11561 ◽  
Author(s):  
Ehab N. El Sawy ◽  
Hany A. El-Sayed ◽  
Viola I. Birss
Keyword(s):  
Precise Determination ◽  
Oxide Formation ◽  
Electronic Interactions ◽  
Co Stripping ◽  
Two Phases ◽  
First Time ◽  
Fingerprinting Methods ◽  
Core Nanoparticles

The electrochemical signatures of Ru oxide formation and CO stripping were used, for the first time, to determine the Pt shell coverage (from 0–2 monolayers) on Ru core nanoparticles, also revealing the chemical and electronic interactions that exist between these two phases.

New approach to precise determination of the capacity of an adsorption monolayer

2006 ◽  
Vol 68 (5) ◽  
pp. 654-654
Author(s):  
G. I. Berezin ◽  
K. O. Murdmaa ◽  
A. A. Fomkin
Keyword(s):  
Precise Determination ◽  
New Approach ◽  
Adsorption Monolayer

scholarly journals Penentuan Aspek Implisit dengan Ekstraksi Knowledge Berbasis Rule pada Ulasan Bahasa Indonesia (Determination of Implicit Aspects with Rule Based Knowledge Extraction in Indonesian Reviews)

2020 ◽  
Vol 9 (1) ◽  
pp. 35-44
Author(s):  
Yuliana Setiowati ◽  
Fitri Setyorini ◽  
Afrida Helen
Keyword(s):  
Knowledge Extraction ◽  
Training Phase ◽  
Threshold Values ◽  
Rule Based ◽  
New Approach ◽  
Word Similarity ◽  
Testing Phase ◽  
Two Phases ◽  
The Relationship

Determination of implicit aspects is one of the important things in opinion sentences. This study proposes a new approach for developing rule-based knowledge by forming a relation between opinion words with aspect categories. The relationship is obtained from the combination of rules, based on Opinion Word Similarity (OWS). Evaluation for rule-based knowledge extraction is in the form of threshold values of frequency and confidence to produce the best precision, recall, and f-measure values. The knowledge extraction consists of two phases: training phase and testing phase. The training phase is described as the process to extract rule-based knowledge. The testing phase is described as the process to obtain the implicit aspects of opinion sentences by referring to rule-based knowledge. To extract rule-based knowledge on user reviews, it is necessary to identify opinion sentences with explicit aspects and get pairs of aspects and words of opinion with rules generated from regular expressions. The evaluation res ult of rule-based knowledge with confidence using OWS showed better results compared to rule-based knowledge without using OWS. By using OWS, precision value increased by 0.25%, recall value increased by 1.15%, and precision value increased by 0.83%.

A New Approach to IDDQ Failure Fault Localization Using Single Shot Logic (SSL) Patterns

2019 ◽  
Author(s):  
Rommel Estores ◽  
Stefaan Verleye
Keyword(s):  
Fault Location ◽  
Fault Localization ◽  
Internal Node ◽  
Precise Determination ◽  
Control Individual ◽  
Single Shot ◽  
New Approach ◽  
Measurement Results ◽  
Defective Area

Abstract In this paper the authors will discuss an application of Single Shot Logic (SSL) patterns used for further localizing IDDQ failures using ATPG constraints and targeted faults. This new method provides the analyst a possibility of performing circuit analysis using IDDQ measurement results as a pass/fail criterion rather than logic mismatches. Once a defective area was partially isolated through fault localization, SSL patterns were created to control individual internal node logic states in a deterministic way. IDDQ was measured at each SSL iteration where schematic analysis can further isolate the failure to a specific location. Two case studies will be discussed to show how this technique was used on actual failing units, with detailed explanation of the steps performed that led to a more precise determination of the fault location in the suspect cell.

Rapid Method for Determination of 2-Hydroxy-4-(Methylthio)butanoic Acid in Poultry Feeds by Capillary Isotachophoresis

1986 ◽  
Vol 69 (3) ◽  
pp. 474-477
Author(s):  
Dutt V Vinjamoori ◽  
Robert M Schisla
Keyword(s):  
Cold Water ◽  
Rapid Determination ◽  
Ionic Species ◽  
Capillary Isotachophoresis ◽  
Butanoic Acid ◽  
Poultry Feeds ◽  
Charged Species ◽  
Order Of Magnitude ◽  
Gas Chromatographic Method

Abstract Capillary isotachophoresis, which involves the separation of charged species under an electric field, has been applied to the rapid determination of 2-hydroxy-4-(methylthio)butanoic acid at 0.04-0.50% concentration levels in corn/soy-based poultry feeds, using conductivity detection. The procedure merely involves a 15 min cold water extraction of the sample and a 15 min analysis after injection of the filtrate into the instrument. Since only charged species migrate and non-ionic species stay virtually at the front of the column, extraordinary selectivity can be achieved. The isotachophoresis method is an order of magnitude faster than the gas chromatographic method reported recently and also provides information on HMB-monomer/dimer ratio in the same run. The sample recoveries exceeded 90% in all concentration ranges studied with coefficients of variation less than ± 10%.

POLAROGRAPHIC DETERMINATION OF THE DISSOCIATION CONSTANT OF THE SULPHYDRYL GROUP AND DIFFUSION COEFFICIENT MEASUREMENTS OF THIOMALIC ACID

1961 ◽  
Vol 39 (11) ◽  
pp. 2236-2239 ◽  
Author(s):  
R. C. Kapoor ◽  
O. P. Agrawal ◽  
T. D. Seth
Keyword(s):  
Diffusion Coefficients ◽  
Polarographic Study ◽  
Standard Potential ◽  
Charged Species ◽  
Half Wave ◽  
Ph Range ◽  
And Diffusion ◽  
Respective Species ◽  
Made In

Polarographic study of thiomalic acid has been made in the pH range 1–12.5 using Britton–Robinson buffer at 30°. The half-wave potential [Formula: see text] values have been used to determine the pK3 (SH) value of the acid (pK3 = 10.55).The diffusion current obtained in these experiments has been utilized to calculate the diffusion coefficients of the different charged species of thiomalic acid. The values thus obtained for the respective species are H3A = 1.20 × 10−5 cm2/sec; H2A− = 1.16 × 10−5 cm2/sec; HA−− = 1.08 × 10−5 cm2/sec; and A−−− = 7.67 × 10−6 cm2/sec.The standard potential of the reaction[Formula: see text]has been calculated as +0.266 volt vs. N.H.E.

Symmetry for elliptic equations in a half-space without strong maximum principle

2004 ◽  
Vol 134 (2) ◽  
pp. 259-269 ◽  
Author(s):  
Yihong Du ◽  
Zongming Guo
Keyword(s):  
Maximum Principle ◽  
Elliptic Equations ◽  
Precise Determination ◽  
Strong Maximum Principle ◽  
New Approach ◽  
Lipschitz Continuous ◽  
Weak Maximum Principle ◽  
Image Position ◽  
Symmetry Result

For a wide class of nonlinearities f(u) satisfying but not necessarily Lipschitz continuous, we study the quasi-linear equation where T = {x = (x1, x2, …, xN) ∈ RN: x1 > 0} with N ≥ 2. By using a new approach based on the weak maximum principle, we show that any positive solution on T must be a function of x1 only. Under our assumptions, the strong maximum principle does not hold in general and the solution may develop a flat core; our symmetry result allows an easy and precise determination of the flat core.

scholarly journals Continuous assay for acid phosphatase using 1-naphthyl phosphate as a substrate.

1997 ◽  
Vol 44 (4) ◽  
pp. 853-860 ◽  
Author(s):  
E Luchter-Wasylewska
Keyword(s):  
Aqueous Solution ◽  
Steady State ◽  
Acid Phosphatase ◽  
Reverse Micelles ◽  
Prostatic Acid Phosphatase ◽  
Precise Determination ◽  
Ph Range ◽  
Phosphatase Assay ◽  
Kinetics Of

The described continuous acid phosphatase assay is based on kinetics of the release of 1-naphthol in the course of the enzyme-catalyzed hydrolysis of 1-naphthyl phosphate, measured at 320 nm in aqueous solution and at 322 nm in sodium-bis(2-ethylhexyl)sulfosuccinate isooctane-water reverse micelles in a broad pH range (1.0-8.2). The method allows precise determination of the initial rate of the reaction and therefore may be used in the steady-state and pre-steady-state studies on the phosphatase-catalyzed reaction. The kinetic parameters (Km and kcat) for human prostatic acid phosphatase in aqueous solution and in reverse micelles, at pH 3.8, 4.5 and 5.7, by the proposed 1-naphthyl phosphate assay have been determined.

scholarly journals A Rapid and High-Precision Mountain Vertex Extraction Method Based on Hotspot Analysis Clustering and Improved Eight-Connected Extraction Algorithms for Digital Elevation Models

2020 ◽  
Vol 13 (1) ◽  
pp. 81
Author(s):  
Zhenqi Zheng ◽  
Xiongwu Xiao ◽  
Zhi-Chao Zhong ◽  
Yufu Zang ◽  
Nan Yang ◽  
...  
Keyword(s):  
Clustering Algorithm ◽  
Extraction Methods ◽  
Precise Determination ◽  
Hotspot Analysis ◽  
New Approach ◽  
Topographic Features ◽  
Digital Elevation ◽  
Extraction Algorithm ◽  
Elevation Model

Digital Elevation Model (DEM)-based mountain vertex extraction is one of the most useful DEM applications, providing important information to properly characterize topographic features. Current vertex-extraction techniques have considerable limitations, such as yielding low-accuracy results and generating false mountain vertices. To overcome these limitations, a new approach is proposed that combines Hotspot Analysis Clustering and the Improved Eight-Connected Extraction algorithms that would quickly and accurately provide the location and elevation of mountain vertices. The use of the elevation-based Hotspot Analysis Clustering Algorithm allows the fast partitioning of the mountain vertex area, which significantly reduces data and considerably improves the efficiency of mountain vertex extraction. The algorithm also minimizes false mountain vertices, which can be problematic in valleys, ridges, and other rugged terrains. The Eight-Connected Extraction Algorithm also hastens the precise determination of vertex location and elevation, providing a better balance between accuracy and efficiency in vertex extraction. The proposed approach was used and tested on seven different datasets and was compared against traditional vertex extraction methods. The results of the quantitative evaluation show that the proposed approach yielded higher efficiency, considerably minimized the occurrence of invalid points, and generated higher vertex extraction accuracy compared to other traditional methods.

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