Method For Quantitative Estimation Research Articles

Development and Validation of High Performance Thin Layer Chromatography Method for Standardization of Polyherbal Formulation Using Mangiferin and Gallic Acid as Markers

Oxitard capsules, a polyherbal formulation, is an effective natural antioxidant that prevents oxidative stress-related tissue damage and is helpful for coronary artery disease. The aim of the present work was systematic development and validation of the high-performance thin-layer chromatographic method for simultaneous quantitative estimation of mangiferin and gallic acid from oxitard capsules. Both markers, mangiferin and gallic acid were separated on a pre-coated silica gel 60 F254 thin-layer chromatographic plate, using toluene:ethyl acetate:formic acid:methanol (4:6:0.8:2 v/v/v/v) as mobile phase. The retention factor of mangiferin and gallic acid was found to be 0.28±0.03 and 0.78±0.03, respectively. The linear regression analysis data for the calibration plots of drugs scanned at isosbestic point 299 nm showed a good linear relationship with r2=0.9931 and r2=0.9901, over the concentration range of 300 to 700 ng/spot and 500 to 900 ng/spot for mangiferin and gallic acid, respectively. The validation parameter followed for simultaneous estimation of these polyherbal drugs were linearity, precision, accuracy, robustness, ruggedness and sensitivity (limit of detection and limit of quantitation). The method was found to be precise, accurate, sensitive and robust meeting all the parameters as per International Council for Harmonisation guideline Q2 (R1). Thus, the developed high-performance thin-layer chromatography method can conveniently be employed for simultaneous detection and quantification of mangiferin and gallic acid in commercial polyherbal formulation.

Методический подход к комплексному описанию объекта информационной защиты

Purpose: on the basis of analysis of a comprehensive approach to the assessment of threats to information security to substantiate a methodological approach to a comprehensive description of the object of information protection with an assessment of its risks. Offer a tool for building private models and information security management system. Research method: use of partial integral index of security, which reflects the average risk of damage during the implementation of a threat of a certain type and characterizes the degree of danger. Analysis of the architecture of the object of assessment in relation to possible violations of information security, information security risk assessment using the apparatus of the theory of fuzzy sets when considering the methodological approach to a comprehensive description of the object of information security with an assessment of its risks. Result: proposed a comprehensive approach to assessing threats to the security of information. The assessment of the state of the protection object in case of violation of security is carried out with the help of particular integral index of security, which characterizes the possibility of inflicting damage in its implementation, according to which the ranking is made. On the basis of this methodical approach to complex description of the object of information protection with an assessment of its risks, using analysis of architecture of the object in application to possible violations of information security, and also making an assessment of risk using the apparatus of the theory of fuzzy sets is substantiated. This methodical approach is a formal tool for building private models and information security management system as a whole. On the basis of these models, it is possible to develop: methods of quantitative estimation of security; methods and approaches to the description of the factors influencing security; methods of security estimation of operating systems with use of the methodological approach to information systems security.

Development of UPLC-MS/MS method and its pharmacokinetic application for estimation of sertraline in rat plasma

The current research aims to develop a rapid, sensitive and robust UPLC-MS/MS method for quantitative estimation of sertraline in rat plasma following oral administration of lipid-based formulation. Different types of isocratic systems were tried for optimization of mobile phase to attain good resolution and appropriate retention time. The multiple reaction monitoring transitions of m/z 306.3 → 159.1 and 515.2 → 276.1 were used to quantify sertraline and internal standard, respectively. The method was validated for different parameters as per the guideline of the United States Food and Drug administration (USFDA). The validated linearity range of sertraline was found to be 1-1,00 ng/mL in rat plasma with 0.1 ng/mL as lower limit of quantification. The intra-day and inter-day precision (RSD%) were within 7.6-10.6% and the accuracies (RE%) were ± 8.0%. The results showed a good percentage recovery of analytes within acceptance limit. No significant degradation of drug in plasma was observed during the stability study. The method demonstrated short analytical run time (< 3 min), low sensitivity (0.1 ng/mL) and requirement of small amount of plasma (50 µL) for extraction procedure.Overall, this method•Results in an optimized and validated assay for estimation of sertraline in plasma.•Offers a cost effective mobile phase with excellent linearity, sensitivity, accuracy, and precision. The method suggested its application in pharmacokinetic study of sertraline administered via oral route.•The method can be used for therapeutic drug monitoring in drug designing. The method can also be used for toxicity and bioequivalence studies.

A novel adsorption-based method for revealing the Si distribution in SAPO molecular sieves: The case of SAPO-11

A novel adsorption-based method for quantitative estimation of the phosphorus atom replacement for a (Si, H+) pair in the SAPO-11 framework is suggested. The most probable configurations and regularities in the location of silicon atoms and protons in the SAPO-11 structure containing 1, 2, 3 and 5 Si atoms per unit cell were determined by computations. A new force field for adsorption simulation in the H2 – SAPO system was developed. The dependence of averaged Henry's constants for H2 adsorption at 77 K on the amount of substituted Si was calculated. The effect of model used for computation of the Si distribution probability in the SAPO-11 on the adsorption properties in the H2 – SAPO system was studied. Practical applications of the method for several SAPO-11 frameworks with different Si concentrations are demonstrated.

Fluorescence Enhancement Based Quantification of Human Serum Albumin from Biological Sample Using Indole Based Nanosuspension: Molecular Interactions and Molecular Docking Studies.

Fluorescent 3-[(E)-(2-phenylhydrazinylidene) methyl]-1H-indole (PHI) was synthesized by condensation of indole-3-carboxaldehyde and phenyl hydrazine in presence of acetic acid and ethanol and after spectral characterization used further to prepare its aqueous nano suspension by reprecipitation method using polyvinylpyrrolidone (PVP) as stabilizer. The average particle size of nano suspension measured by Dynamic Light Scattering (DLS) was found 77.5nm while FESEM microphotograph showed spherical morphology. The blue shift in the absorption spectrum and stokes shifted fluorescence of nanosuspension of PHI compared to its monomer spectrum in dilute solution indicate formation of H-type aggregate by face to face overlapping of the molecules.The aggregation induced enhanced emission (AIEE) of PVP capped nanosuspension of PHI is increased appreciably by presence of aqueous solution of human serum albumin (HSA). A suitable mechanism of molecular binding interactions based on complex formation between PHI nanoaggregate and HSA through PVP is proposed. Fluorescence life time, zeta potential and particle size data of PHI nanoparticles (PHINPs) obtained in presence of different amounts of HSA are in support of molecular interactions leading to complex formation. The molecular docking studies showed that HSA and PVP capped PHINPs exhibit strong hydrogen bonding interaction. The fluorescence enhancement effect induced in PHI nanosuspension is used further to develop analytical method for quantitative estimation of HSA in aqueous biological sample solution.

Development, validation and application of RP-HPLC method for quantitative estimation of wedelolactone in different accessions and plant parts of Eclipta alba (L.)

Development, validation and application of RP-HPLC method for quantitative estimation of wedelolactone in different accessions and plant parts of Eclipta alba (L.)

Raman spectroscopy study of the secondary actinolite in gabbrodiorite intrusive rocks from Varan area, Urumieh-Dokhtar Magmatic Arc, Iran

Mineralogical studies play a key role in deciphering mineral’s formation and associated geochemical processes in geosciences. This paper presents the application of Raman spectroscopy to the characterization of actinolite in rock samples. The studied actinolite was formed as the pseudomorph of primary pyroxene in gabbrodiorite intrusive rock sample collected from Varan area, Urumieh-Dokhtar Magmatic Arc of Iran. The Raman spectra of micrometer-sized actinolite grains embedded in a crude rock sample are compared with the corresponding literature data for actinolite and tremolite in range of 200-1200 cm-1 and 3600-3700 cm-1 region. The results show that the quantitative estimation of Mg# = Mg/(Mg+Fe2+) can be obtained from the fractional intensities of the OH-stretching bands by applying Raman spectroscopy to micrometer-sized actinolite grains in a crude rough rock sample, which is in good agreement with the results from EMPA. The Raman spectroscopy is a fast method and low-cost for quantitative estimation of Mg# in actinolite.

Quality by Design Methodology to Develop and Validate a UPLC-QToFMS Method for Simultaneous Estimation of Ergocalciferol, Cholecalciferol, Phylloquinone, Menaquinone-4, Menaquinone-7, and Menadione in Prepared Tablet and Vitamin Supplements

The Quality by Design (QbD) method was used to develop a new simple, rapid, and sensitive ultra-performance liquid chromatography and time of flight mass spectrometric (UPLC-QToFMS) method for quantitative estimation of ergocalciferol (D 2 ), cholecalciferol (D 3 ), phylloquinone (K 1 ), menaquinone-4 (K 2 -4), menaquinone-7 (K 2 -7), and menadione (K 3 ). Four independent parameters were tested using a full factorial design (FFD): pH of the aqueous component of the mobile phase, flow rate, injection volume, and percentage of the organic modifier. Two factors were discovered to be significant using analysis of variance (ANOVA). To further optimise chromatographic conditions, a central composite design (CCD) was used. At a flow rate of 0.5 mL/min and an injection volume of 5 µL, the analysis was carried out on an Accucore C-18 (50 x 4.6 mm; 2.6 µm) column with a gradient mobile phase containing methanol and 0.1% formic acid buffer, pH 3.5. The proposed method was validated under optimal conditions, with a linear range of 15 to 1500 ng/mL for analytes and correlation coefficient (R 2 ) values greater than 0.99. The percentage of analyte recovery ranged from 97.19 to 100.84 percent. RSD values for both inter-day and intra-day precisions were less than 1%. The proposed method was discovered to be precise, specific, and robust.

Electrochemical Methods for Quantitative Estimation of Ambroxol Hydrochloride in drug for the Treatment of Asthmatic Bronchitis

Electrochemical Methods for Quantitative Estimation of Ambroxol Hydrochloride in drug for the Treatment of Asthmatic Bronchitis

Количественная оценка скорости коррозии металлических материалов с помощью конфокальной лазерной сканирующей микроскопии

This study represents an alternative method for quantitative estimation of the corrosion rate of various metallic materials, in particular magnesium and its alloys, using confocal laser scanning microscopy (CLSM). This method makes it possible to obtain not only optical images of the specimen surface, but also accurate 3D height maps which allow a quantitative assessment of many characteristics such as surface profile, damage locality, number and maximum depth of corrosion pits, volume of metal loss and corrosion products. Specific methodological aspects and possibilities of using the CLSM method for the analysis of corrosion damage have been described. The proposed method is based on obtaining 3D images of the surface of specimens after corrosion tests with their subsequent processing and analysis, with the use of original software computer procedures for digital image processing and topographic data arrays. A technique for recording and subsequent analysis of specimens after corrosion tests using CLSM has been developed and tested. The optimal magnification, lens type, scanning step and noise filtering have been determined. The procedure prescribes mounting the test metallic sample into a non-corrosive material to create a stable reference plane surface. The dissolution of the metal at the specimen-mount interface is found to be notably more intensive than in the specimen interior when the conventional metallographic resins are used as the mount. This fact deteriorates the objectivity of the results of corrosion rate measurements. Polyethylene is proposed as the mounting material to minimize this effect. The geometry and the minimum size of the metal sample, providing a reduction in labor contribution for scanning and data processing without loss of accuracy and reliability of the data are established. The values of the uniform corrosion rate of commercially pure magnesium in Ringer's solution using the gravimetric method and the CLSM method showed satisfactory repeatability of measurements.

New Method of Oil Reservoir Rock Heterogeneity Quantitative Estimation from X-ray MCT Data

This paper considers a new method for “pore scale” oil reservoir rock quantitative estimation. The method is based on core sample X-ray tomography data analysis and can be directly used to both classify rocks by heterogeneity and assess representativeness of the core material collection. The proposed heterogeneity criteria consider the heterogeneity of pore size and heterogeneity of pore arrangement in the sample void and can thus be related to the drainage effectiveness. The classification of rocks by heterogeneity at the pore scale is also proposed when choosing a reservoir engineering method and may help us to find formations that are similar at pore scale. We analyzed a set of reservoir rocks of different lithologies using the new method that considers only tomographic images and clearly distributes samples over the structure of their pore space.

Development and validation of UPLC method for quantitative estimation of related impurities in tizanidine hydrochloride tablets

Quantitative Estimation of Piperine in Piper nigrum and Piper longum Using High Performance Thin Layer ChromatographyP.D.Hamrapurkar, Kavita Jadhav, Sandip Zine

CEO-To-Worker Pay Ratio, Say On Pay Votes, and Executive Compensation

This study investigates the extent to which the CEO-to-Worker pay ratio affects shareholders’ say on pay votes and consequently examine whether shareholder opposition to pay gaps influence future CEO compensation. The effects of the implementation of the CEO-to-Worker pay ratio disclosure rule (2017) and the Portland Surplus tax (2018) are also discussed. We employ a large and up-to-date sample of US Russell 3,000 companies with 13,885 firm-year observations from 2011 to 2018. We develop and employ a unique measure of the CEO-to-Worker pay ratio allowing us to study time-periods for which data is not available. Using different quantitative estimation methods, we found that the CEO-to-Worker pay ratio is significantly and positively associated with shareholder dissent votes and that a pay gap opposition from shareholders is negatively and significantly associated with future CEO compensation. In addition, mandatory disclosure of the CEO-to-Worker pay ratio has increased the number of shareholder dissent votes the year after its implementation in 2017. By contrast, companies identified by the Portland Surplus tax have not shown higher shareholder dissent votes nor lower future CEO compensation compared to the Russell 3,000 companies. This study has important implications for the corporate governance literature, corporate directors, and policymakers.

Model-based autonomous plate defects visualization method for quantitative wall-thinning estimation

The visualization of the wall thinning of plate-like structures using scanning laser Doppler vibrometry (SLDV) is a promising method in nondestructive evaluation using laser ultrasonics. In particular, the Lamb-wave-based SLDV method that uses continuous excitation exhibits excellent performance for the estimation of the wall thinning of plates. Currently, plate thickness is quantitatively evaluated based on wavenumber analysis using measured signals. However, it is difficult to estimate plate thickness automatically below the product of frequency and thickness of 6 MHz·mm without knowing the wavenumber sensitivity and minimum wavenumber distance from reference mode owing to the lack of the physical understanding of Lamb waves. In this study, a model-based autonomous plate defects visualization method is proposed for the quantitative imaging of the wall thinning of plates so that inspectors can use scanning laser Doppler vibrometry (SLDV) without any knowledge of Lamb waves and its signal processing. Interdigital-transducer-based SLDV is utilized to validate the proposed method, and a 6-mm-thick carbon steel plate with 1–8% wall thinning, and a 2-mm-thick aluminum plate with Y-shaped wall thinning are used. Experiments demonstrate that the capability of the proposed method for detecting wall thinning in plates is equivalent to that of manual plate defects visualization method.

Pressure-based estimation of right ventricular ejection fraction: Validation as a clinically relevant target for drug development in a rodent model of pulmonary hypertension

Depressed right ventricular ejection fraction (RVEF) has clear prognostic significance in patients with pulmonary arterial hypertension (PAH). Accordingly, improvements in RVEF represent a desirable end-point in the development of PAH therapies. However, current methods for determination of RVEF require measurement of RV volume and are relatively complex and costly. Here, we validate a novel method for quantitative estimation of RVEF in rats based entirely upon analysis of readily available RV pressure waveforms that eliminates the need for simultaneous volume measurement and can be rapidly applied.Right ventricular pressure and volume (conductance catheter) measurements acquired from 15 rats (7 controls, 8 sugen/hypoxia PAH; 220–250 g) were used for the study. Over the same 10 beat interval, RVEF was directly measured from the volume signal and estimated from the pressure signal. Simultaneous measures were compared by linear regression and Bland-Altman analysis to define bias (accuracy) and precision.Measured RVEF ranged from 0.19 to 0.60 (mean 0.44 ± 0.10) and estimated from 0.19 to 0.52 (mean 0.42 ± 0.09). Across the dataset there was strong correlation (r2 = 0.813), with minimal bias (0.01) and an overall error of 20% consistent with acceptable accuracy and precision.Study results support the potential utility of a method based entirely upon analysis of the RV pressure waveform for assessing drug effects on RVEF in rat models of PAH.

Translation of the realias of state-administrative structure and public life from English language into the Russian language

This article provides an overview of the Russian and foreign classifications of realias, and the results of research conducted by the authors on the ways of conveying the realias of state-administrative structure and public life from the English language into the Russian language (based on the novel "Rebecca" by Daphne Du Maurier and its translation into the Russian language by G. Ostrovskaya). The goal of this is to determine the peculiarities and most effective ways of conveying the realias in the literary work, considering the specificity of literary translation, which requires preserving the flair, imagery, and aesthetic impact the original. The article employs the method of continuous sampling, quantitative estimation, linguistic observation and description, and comparative method. The conducted research contributes to studying the effectiveness of different ways of translating the realias in a literary text from the English language into the Russian language. The novelty of consist in the fact that this article is first to examine the language material and translation solutions from two perspectives &amp;ndash; the theory of linguistic translation and the theory of interpretative translation. The conclusion is made that in conveying the realias, in some instances, the translator shifts away from the standard ways in order to make the text comprehensible for the Russian-speaking recipient. At the same time, this is the why the methods justified from the standpoint of linguistic theory of translation leads to a loss of flair and semantic nuances. The acquired materials and results can be valuable for pedagogical and educational purposes, as well as in professional English &amp;ndash; Russian translations that contain non-equivalent vocabulary.

Method Development and Validation of Salmeterol xinofoate by HPLC

A rapid and precise high performance liquid chromatography method has been developed for the validation of Salmeterol xinofoate in its pure dosage form. The separation was carried out on Agilent Zorbax Bonus RP- (250mm ×4.6mm 5μ) column with a mobile phase consisting of 0.1% Formic acid: Acetonitrile in the ratio of 64:36 v/v as a mobile phase and flow rate is 1ml/min. The detection was carried out at wavelength 234nm. The column thermostatically controlled at 30℃. The retention time of Salmeterol was found to be 1.96 min. The Salmeterol xinofoate followed linearity in the concentration range of 40-60μg/mL with r2= 0.999. The developed method was validated for sensitivity, accuracy and precision. The sample was scanned from 200- 400nm with PDA detector. The % recovery of sample was found to be. The LOD and LOQ of the Salmeterol xinofoate was found to be 2.67μg/ml and 8.08μg/ml respectively. The suitability of this HPLC method for quantitative estimation of Salmeterol xinofoate was proved by validation by the requirements of ICH guidelines.

Development and Validation of Chromatographic Method for the Standardization of Homeopathic Formulation of Syzygium Cumini.

Syzygium cumini (Lam.), family Myrtaceae, has a long history of use in folk and traditional systems of indigenous medicine. Many homeopathic formulations of Jamun seeds are available in the market for their crucial usage as an anti-diabetic. Despite the popularity of homeopathic products, a lack of standard quality is a significant impediment in their acceptance. The present study aimed to develop and validate a chromatographic method for the standardization of the homeopathic formulation of Syzygium cumini. The seeds of Syzygium cumini were studied for physicochemical evaluation and preliminary phytochemical screening. Also, the in-house standard and marketed homeopathic formulations of Syzigium cumini were standardized for pH, total fatty content, total phenolic and flavonoid content, with quantitative high-performance liquid chromatography- photodiode array detector (HPLC-PDA) analysis by using ellagic acid as a marker. The physicochemical characteristics of crude material were found to be within pharmacopeial limits. The phytochemical screening showed the presence of various secondary metabolites. The total phenolic and flavonoid content was higher in the in-house standard than in marketed formulations. A validated quantitative HPLC-PDA analysis showed variations of ellagic acid content in different homeopathic formulations. Physicochemical analysis and the HPLC method for quantitative estimation of ellagic acid can be used to standardize a homeopathic formulation of Syzygium cumini.

Validation of Optimized Method for Quantitative Estimation of Extracellular Ethanol from Micro-algae

Validation of Optimized Method for Quantitative Estimation of Extracellular Ethanol from Micro-algae

Lateral Position-Dependent Velocity Estimation Error in Plane-Wave Doppler Ultrasound Systems

Doppler ultrasound has become a standard method used to diagnose and grade vascular diseases and monitor their progression. Conventional focused-beam color Doppler imaging is routinely used in clinical practice, but suffers from inherent trade-offs between spatial, temporal and velocity resolution. Newer, plane-wave Doppler imaging offers rapid simultaneous acquisition of B-mode, color and spectral Doppler information across large fields of view, making it a potentially useful method for quantitative estimation of blood flow velocities in the clinic. However, plane-wave imaging can lead to a substantial error in velocity estimation, which is dependent on the lateral location within the image. This is seen in both clinical and experimental plane-wave systems. In the work described in this article, we quantified this velocity error under different geometric and beamforming conditions using numerical simulation and experimental phantoms. We found that the lateral-dependent velocity errors are caused by asymmetrical geometric spectral broadening, and outline a correction algorithm that can mitigate these errors.