scholarly journals Sensitivity and Selectivity on Aptamer-Based Assay: The Determination of Tetracycline Residue in Bovine Milk

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Sohee Jeong ◽  
Insook Rhee Paeng
Keyword(s):  
Dynamic Range ◽  
Bovine Milk ◽  
Point Of View ◽  
Dna Aptamer ◽  
Binding Assays ◽  
Good Tool ◽  
Sensitivity And Selectivity ◽  
Data Points ◽  
Aptamer Assay

A competitive enzyme-linked aptamer assay (ELAA) to detect tetracycline in milk was performed by using two different aptamers individually; one is 76 mer-DNA aptamer and the other is 57 mer-RNA aptamer. The best optimum condition was obtained without monovalent ion, Na+and also by adding no Mg2+ion in the assay buffer, along with RT incubation. The optimized ELAA showed a good sensitivity (LOD of 2.10 × 10−8M) with a wide dynamic range (3.16 × 10−8M ~ 3.16 × 10−4M). In addition, the average R.S.D. across all data points of the curve was less than 2.5% with good recoveries (~101.8%) from the milk media. Thus, this method provides a good tool to monitor tetracycline in milk from MRLs’ point of view. However, this ELAA method was not superior to the ELISA method in terms of specificity. This paper describes that it does not always give better sensitivity and specificity in assays even though aptamers have several advantages over antibodies and have been known to be good binders for binding assays.

scholarly journals Potentiometric Signal Transduction for Selective Determination of 1-(3-Chlorophenyl)piperazine “Legal Ecstasy” Through Biomimetic Interaction Mechanism

Chemosensors ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 46
Author(s):  
Eman El-Naby
Keyword(s):  
Dynamic Range ◽  
Limit Of Detection ◽  
Interaction Mechanism ◽  
High Sensitivity ◽  
Fast Response ◽  
Polymeric Membrane ◽  
Selective Determination ◽  
Sensitivity And Selectivity ◽  
Pharmacologically Active

1-(3-chlorophenyl)piperazine (mCPP) is a wide spread new psychoactive substance produces stimulant and hallucinogenic effects similar to those sought from ecstasy. Hence, in the recent years, mCPP has been introduced by the organized crime through the darknet as a part of the illicit ecstasy market with a variable complex profile of pharmacologically active substances that pose problematic risk patterns among people who take these seized products. Accordingly, the design of selective sensors for the determination of mCPP is a very important demand. In this respect, a supramolecular architecture; [Na(15-crown-5)][BPh4] from the assembly of 15-crown-5 and sodium tetraphenylboron has been utilized as an ionophore, for the first time in the selective recognition of mCPP in conjunction with potassium tetrakis(p-chlorophenyl)borate and dioctylphthalate through polymeric membrane ion sensors. The ionophore exhibited a strong binding affinity that resulted in a high sensitivity with a slope closed to the ideal Nernstian value; 58.9 ± 0.43 mV/decade, a larger dynamic range from 10−6 to 10−2 M, a lower limit of detection down to 5.0 × 10−7 M and a fast response time of 5 s. Very important also is it was afforded excellent selectivity towards mCPP over psychoactive substances of major concern, providing a potentially useful system for the determination of mCPP in the illicit market. On comparison with the natural β-cyclodextrin as an ionophore, it exhibited more sensitivity and selectivity estimated to be the superior.

Determination of Morantel-Related Residues in Bovine Milk by Electron Capture Gas Chromatography

1986 ◽  
Vol 69 (4) ◽  
pp. 646-651
Author(s):  
Martin J Lynch ◽  
Donald M Burnett ◽  
Franklyn R Mosher ◽  
Mary E Dimmock ◽  
S Richard Bartolucci
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Dynamic Range ◽  
Bovine Milk ◽  
Internal Standard ◽  
Mean Values ◽  
Accuracy And Precision ◽  
Control Milk ◽  
Hydrolysis Of

Abstract A gas chromatographic assay was developed to determine major residues of morantel in bovine milk over a range that is suitable for monitoring residues of the drug. The method is based on hydrolysis of the N-methyl-tetrahy dropyrimidine portion of morantel and its metabolites to N-mefhyl-1,3-propanediamine, and converting the diamine to an N,N-bis-(2-nitro-4-trifluoromethylphenyl) derivative. The addition of an internal standard, the N-desmethyl-N-ethyl homolog of pyrantel, to the milk sample circumvents any potential problem that could arise from variable reaction yields, and eliminates the true recovery as a factor affecting the accuracy and precision of the procedure. The concentrations of the derivatives are determined by pulsed electron capture gas chromatography over a linear dynamic range that is equivalent to 12.5-50 ppb morantel. The method was evaluated at the 0, 12.5,25, and 50 ppb levels in fortified bovine milk, and in a withdrawal sample containing physiologically incurred morantel residues. Mean values of 14 ± 1.7,24 ± 3.7, and 47 ± 6.9 were found for the fortified samples, approximately 3 ppb for control milk, and 16 ± 1.7 ppb for the withdrawal sample.

scholarly journals Determination of Enrofloxacin in Bovine Milk by a Novel Single-Stranded DNA Aptamer Chemiluminescent Enzyme Immunoassay

2014 ◽  
Vol 47 (17) ◽  
pp. 2844-2856 ◽  
Author(s):  
Hengjia Ni ◽  
Suxia Zhang ◽  
Xinghua Ding ◽  
Tiejun Mi ◽  
Zhanhui Wang ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
Bovine Milk ◽  
Dna Aptamer ◽  
Single Stranded Dna ◽  
Chemiluminescent Enzyme Immunoassay

Determination of the International Sensitivity Index of a New Near-Patient Testing Device to Monitor Oral Anticoagulant Therapy

1997 ◽  
Vol 78 (02) ◽  
pp. 855-858 ◽  
Author(s):  
Armando Tripodi ◽  
Veena Chantarangkul ◽  
Marigrazia Clerici ◽  
Barbara Negri ◽  
Pier Mannuccio Mannucci
Keyword(s):  
Linear Relationship ◽  
Whole Blood ◽  
Oral Anticoagulant ◽  
Oral Anticoagulant Therapy ◽  
Oral Anticoagulants ◽  
Calibration Model ◽  
Testing Device ◽  
Data Points ◽  
Near Patient Testing

SummaryA key issue for the reliable use of new devices for the laboratory control of oral anticoagulant therapy with the INR is their conformity to the calibration model. In the past, their adequacy has mostly been assessed empirically without reference to the calibration model and the use of International Reference Preparations (IRP) for thromboplastin. In this study we reviewed the requirements to be fulfilled and applied them to the calibration of a new near-patient testing device (TAS, Cardiovascular Diagnostics) which uses thromboplastin-containing test cards for determination of the INR. On each of 10 working days citrat- ed whole blood and plasma samples were obtained from 2 healthy subjects and 6 patients on oral anticoagulants. PT testing on whole blood and plasma was done with the TAS and parallel testing for plasma by the manual technique with the IRP CRM 149S. Conformity to the calibration model was judged satisfactory if the following requirements were met: (i) there was a linear relationship between paired log-PTs (TAS vs CRM 149S); (ii) the regression line drawn through patients data points, passed through those of normals; (iii) the precision of the calibration expressed as the CV of the slope was <3%. A good linear relationship was observed for calibration plots for plasma and whole blood (r = 0.98). Regression lines drawn through patients data points, passed through those of normals. The CVs of the slope were in both cases 2.2% and the ISIs were 0.965 and 1.000 for whole blood and plasma. In conclusion, our study shows that near-patient testing devices can be considered reliable tools to measure INR in patients on oral anticoagulants and provides guidelines for their evaluation.

Simultaneous Determination of Alogliptin, Linagliptin, Saxagliptin, and Sitagliptin in Bulk Drug and Formulation by UPLC Q-TOF-MS

2020 ◽  
Vol 17 (1) ◽  
pp. 95-105
Author(s):  
Ramji Rathod ◽  
Faraat Ali ◽  
Amrish Chandra ◽  
Robin Kumar ◽  
Meenakshi Dahiya ◽  
...  
Keyword(s):  
Internal Standard ◽  
Gradient Elution ◽  
Ultra Performance Liquid Chromatography ◽  
Pharmaceutical Dosage Forms ◽  
Sensitivity And Selectivity ◽  
The Mean ◽  
Bulk Drug ◽  
Positive Ion ◽  
Higher Sensitivity

Background: A simple and sensitive Ultra Performance Liquid Chromatography-Mass Spectrometry method was developed and validated to measure the concentrations of Alogliptin (ALO), Linagliptin (LIN), Saxagliptin (SAX), and Sitagliptin (SIT) using Pioglitazone (PIO) as an internal standard. Methods: Chromatographic separation of six gliptins was achieved on a C-18 column (100×2.1 mm, 2.7 μm) using a mobile phase consisting of formic acid in water, 0.1%v/v: acetonitrile in gradient elution. Electrospray ionization (ESI) source was operated in the positive ion mode. Targeted MS/MS mode on a QTOF MS was used to quantify the drug utilizing the transitions of 340.1(m/z), 473.2 (m/z), 316.2 (m/z), 408.1 (m/z), and 357.1 (m/z) for ALO, LIN, SAX, SIT and PIO respectively. Results: As per ICH Q2R1 guidelines, a detailed validation of the method was carried out and the standard curves were found to be linear over the concentration ranges of 1516.0-4548.1 ng mL-1, 519.8- 1559.4 ng mL-1, 1531.4-4594.3 ng mL-1and 1519.6-4558.8 ng mL-1 for ALO, LIN, SAX and SIT respectively. Precision and accuracy results were within the acceptable limits. The mean recovery was found to be 98.8 _ 0.76 % (GEM), 102.2 _ 1.59 % (LIN), 95.3 _ 2.74 % (SAX) and 99.2 _ 1.75 % (SIT) respectively. Conclusions: The optimized validated UPLC QTOF-MS/MS method offered the advantage of shorter analytical times and higher sensitivity and selectivity. The optimized method is suitable for application in quantitative analysis of pharmaceutical dosage forms for QC laboratory.

scholarly journals Evaluation of the Ability to Accurately Produce Angular Details by 3D Printing of Plastic Parts

Machines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 150
Author(s):  
Andrei Marius Mihalache ◽  
Gheorghe Nagîț ◽  
Laurențiu Slătineanu ◽  
Adelina Hrițuc ◽  
Angelos Markopoulos ◽  
...  
Keyword(s):  
3D Printing ◽  
Point Of View ◽  
Vertex Angle ◽  
Function Type ◽  
Constant Height ◽  
3D Printers ◽  
3D Printed ◽  
Mathematical Processing ◽  
Plastic Parts

3D printing is a process that has become widely used in recent years, allowing the production of parts with relatively complicated shapes from metallic and non-metallic materials. In some cases, it is challenging to evaluate the ability of 3D printers to make fine details of parts. For such an assessment, the printing of samples showing intersections of surfaces with low angle values was considered. An experimental plan was designed and materialized to highlight the influence of different factors, such as the thickness of the deposited material layer, the printing speed, the cooling and filling conditions of the 3D-printed part, and the thickness of the sample. Samples using areas in the form of isosceles triangles with constant height or bases with the same length, respectively, were used. The mathematical processing of the experimental results allowed the determination of empirical mathematical models of the power-function type. It allowed the detection of both the direction of actions and the intensity of the influence exerted by the input factors. It is concluded that the strongest influence on the printer’s ability to produce fine detail, from the point of view addressed in the paper, is exerted by the vertex angle, whose reduction leads to a decrease in printing accuracy.

Determination of a Rubber-Like Material Model as an Inverse Problem

2011 ◽  
Vol 70 ◽  
pp. 225-230 ◽  
Author(s):  
Agnieszka Derewonko ◽  
Andrzej Kiczko
Keyword(s):  
Selection Process ◽  
Axial Stress ◽  
Constitutive Models ◽  
Material Model ◽  
Polyester Fabric ◽  
Point Of View ◽  
Air Cushion ◽  
Ill Conditioning ◽  
Stress States

The purpose of this paper is to describe the selection process of a rubber-like material model useful for simulation behaviour of an inflatable air cushion under multi-axial stress states. The air cushion is a part of a single segment of a pontoon bridge. The air cushion is constructed of a polyester fabric reinforced membrane such as Hypalon®. From a numerical point of view such a composite type poses a challenge since numerical ill-conditioning can occur due to stiffness differences between rubber and fabric. Due to the analysis of the large deformation dynamic response of the structure, the LS-Dyna code is used. Since LS-Dyna contains more than two-hundred constitutive models the inverse method is used to determine parameters characterizing the material on the base of results of the experimental test.

Resistance to Outflow of Cerebrospinal Fluid Determined by Bolus Injection Technique and Constant Rate Steady State Infusion in Humans

Neurosurgery ◽  
1985 ◽  
Vol 16 (3) ◽  
pp. 336-340 ◽  
Author(s):  
Michael Kosteljanetz
Keyword(s):  
Cerebrospinal Fluid ◽  
Steady State ◽  
Bolus Injection ◽  
Point Of View ◽  
Injection Technique ◽  
Communicating Hydrocephalus ◽  
Constant Rate ◽  
High Degree ◽  
Infusion Technique

Abstract Two methods for the determination of resistance to the outflow of cerebrospinal fluid, the bolus injection technique and the constant rate steady state infusion technique, were compared. Thirty-two patients with a variety of intracranial diseases (usually communicating hydrocephalus) were studied. There was a high degree of correlation between the resistance values obtained with the two methods, but values based on the bolus injection technique were systematically and statistically significantly lower than those obtained with the constant rate infusion test. From a practical point of view. both methods were found to be applicable in a clinical setting.

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