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An elegant, simple, and exact analytical solution (AS) was obtained for a large range of elementary steps with practical importance in free radical polymerization. The AS matches excellently with the numerical solution for the fou...
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An elegant, simple, and exact analytical solution (AS) was obtained for a large range of elementary steps with practical importance in free radical polymerization. The AS matches excellently with the numerical solution for the four cases of monomer- polymer systems studied ranging from the slowest to the fastest. It works equally well for different initiators, different initiator and monomer concentrations, presence or absence of solvent, various solvent volume fractions, and different temperatures. It also matches quite well with experimental data reported in the literature. This AS is not only in line with previous published solutions but also extends their applicability in a natural way. Overall, the conceptual correctness as well as predictive capabilities of the derived AS are established beyond doubt. This AS has the potential to be used in various practical applications such as model based process control, CFD simulations, and so forth.
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The master equation is used extensively to model chemical reaction systems with stochastic dynamics. However, and despite its phenomenological simplicity, it is not in general possible to compute the solution of this equation. Dra...
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The master equation is used extensively to model chemical reaction systems with stochastic dynamics. However, and despite its phenomenological simplicity, it is not in general possible to compute the solution of this equation. Drawing exact samples from the master equation is possible, but can be computationally demanding, especially when estimating high-order statistical summaries or joint probability distributions. As a consequence, one often relies on analytical approximations to the solution of the master equation or on computational techniques that draw approximative samples from this equation. Unfortunately, it is not in general possible to check whether a particular approximation scheme is valid. The main objective of this paper is to develop an effective methodology to address this problem based on statistical hypothesis testing. By drawing a moderate number of samples from the master equation, the proposed techniques use the well-known Kolmogorov-Smirnov statistic to reject the validity of a given approximation method or accept it with a certain level of confidence. Our approach is general enough to deal with any master equation and can be used to test the validity of any analytical approximation method or any approximative sampling technique of interest. A number of examples, based on the Schl?gl model of chemistry and the SIR model of epidemiology, clearly illustrate the effectiveness and potential of the proposed statistical framework.
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As summarized in Part I, in any regulated environment ana--lytica method validation is a critical part of the overall process of vali-dation (1). Analytical method validation is a part of the validation process that establishes, t...
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As summarized in Part I, in any regulated environment ana--lytica method validation is a critical part of the overall process of vali-dation (1). Analytical method validation is a part of the validation process that establishes, through laboratory studies, that the performance characteristics of the method meet the requirements for the intended analytical application and provides an assurance of reliability during normal use; sometimes referred to as "the process of providing documented evidence that the method does what it is intended to do." Regulated laboratories must perform analytical method validation to be in compliance with government or other regulators, in addition to being good scientists. A well-defined and well-documented validation process not only provides evidence that the system and method is suitable for its intended use, but it can aid in transferring the method and satisfy regulatory compliance requirements.
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Building energy simulation analysis plays an important supporting role in the conservation of building energy. Since the early 1980s, researchers have focused on the development and validation of building energy modeling programs ...
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Building energy simulation analysis plays an important supporting role in the conservation of building energy. Since the early 1980s, researchers have focused on the development and validation of building energy modeling programs (BEMPs) and have basically formed a set of systematic validation methods for BEMPs, mainly including analytical, comparative, and empirical methods. Based on related papers in this field, this study systematically analyzed the application status of validation methods for BEMPs from three aspects, namely, sources of validation cases, comparison parameters, and evaluation indicators. The applicability and characteristics of the three methods in different validation fields and different development stages of BEMPs were summarized. Guidance were proposed for researchers to choose more suitable validation methods and evaluation indicators. In addition, the current development trend of BEMPs and the challenges faced by validation methods were investigated, as well as the existing progress of current validation methods under this trend was analyzed. Subsequently, the development direction of the validation method was clarified.
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Genetic testing is a rapidly expanding area with many clinical applications. While the introduction of new genetic tests creates tremendous potential for improving patient care, it is essential to adequately evaluate these tests t...
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Genetic testing is a rapidly expanding area with many clinical applications. While the introduction of new genetic tests creates tremendous potential for improving patient care, it is essential to adequately evaluate these tests to ensure their accuracy and utility for clinical practice. This article describes a general approach to the evaluation of genetic tests and discusses common challenges that evaluators face. This article's goal was to provide a starting point for those who are concerned with the safety and utility of genetic tests to develop an overall strategy to perform the assessment.
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Among the main concerns of the researchers is the comparability of the analysis methods, in order to highlight possible errors. Several statistical approaches and graphical tools are available to investigate sources of analytical ...
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Among the main concerns of the researchers is the comparability of the analysis methods, in order to highlight possible errors. Several statistical approaches and graphical tools are available to investigate sources of analytical error and for decision-making. In this article, we present an operative protocol for the comparison of the precision for two laboratories with the same quantitative analytical methods. This paper describes the importance of achieving sequential stages, including experimental design, familiarization with the method of optimal research analysis, quality evaluation, selection of sample, definition of acceptability criteria. Sample measurement, data analysis and evaluation, final decision and reporting are also discussed and exemplified. The reason for performing a comparison experiment is to estimate the type and magnitude of systematic error between two laboratories with the same method and to judge if the two laboratories are identical within the inherent imprecision methods or within preset analytical quality specifications. Finally, the purpose was to check if same ranges of concentrations and fluxes of pollutants are obtained using the same methods of analysis, but in two different labs.
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Carvone volatile oil is a commercial product that is widely used in the food, cosmetic and pharmaceutical industry due to its fragrance, flavoring and medicinal properties. A validated HPLC method for the qualitative and quantitat...
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Carvone volatile oil is a commercial product that is widely used in the food, cosmetic and pharmaceutical industry due to its fragrance, flavoring and medicinal properties. A validated HPLC method for the qualitative and quantitative analysis of this oil in raw and commercial products is not available in the literature. The aim of this study is to develop a validated new analytical HPLC method for the estimation of Carvone in raw materials and suppositories. The HPLC analysis was carried out using a reversed phase-C18 (250 × 4.0 mm, 5 μm) column. Chromatographic analysis was carried out using a Shimadzu HPLC system equipped with an LC-2010 pump, LC-2010 autosampler, LC-2010 oven, and LC-2010 UV–VIS detector. The mobile consists of two phases Methanol and 1.0 mL of trifluoroacetic acid in 1000 mL filtered and degas HPLC water. The developed HPLC analytical method was simple and was validated in accordance with FDA and ICH guidelines and showed good linearity, accuracy, precision, selectivity and the system suitability results were within the acceptance criteria. This new analytical method could be used to screen the quality of the oil in formulation studies of the final product formulations and can be applied for routine analysis of carvone in raw material as well as in pharmaceutical suppositories and can be applied in any lab and industrial batch quality control.
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Scope for the analytical description of zonal flows and thermodynamic fields in cyclostrophic and geostrophic balance on the sphere is explored in both deep and shallow formulations. Closed‐form zonal flow solutions are given for...
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Scope for the analytical description of zonal flows and thermodynamic fields in cyclostrophic and geostrophic balance on the sphere is explored in both deep and shallow formulations. Closed‐form zonal flow solutions are given for much wider classes of temperature field than those employed in an earlier study. As well as being of scientific interest, these solutions find application in numerical model development and testing. Some considerations for the comparison of deep and shallow formulations using the solutions are noted. ? 2011 British Crown copyright, the Met Office. Published by John Wiley & Sons Ltd.
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MicroRNAs (miRNAs), small noncoding RNAs, are involved in tumorigenesis and in the development of various cancers. Quantitative real-time polymerase chain reaction (qPCR) is the most commonly used tool to investigate miRNA express...
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MicroRNAs (miRNAs), small noncoding RNAs, are involved in tumorigenesis and in the development of various cancers. Quantitative real-time polymerase chain reaction (qPCR) is the most commonly used tool to investigate miRNA expression, and qPCR low-density arrays are increasingly being used as an experimental technique for both the identification of potentially relevant miRNAs and their subsequent validation. Due to the reduced number of microRNAs to be validated, this phase is generally performed on ad hoc customized cards for which a technical robustness is assumed similar to that of the high-throughput cards used during the identification phase. With the aim of investigating the degree of reproducibility between the 2 types of cards, we analyzed plasma-circulating miRNAs evaluated in 60 subjects enrolled in a colorectal cancer screening program. Our results showed a reproducibility between the 2 methods that was not fully satisfactory, with a concordance correlation coefficient equal to 0.69 (95% confidence interval, 0.12-0.92). This report highlights the need to add a technical validation step to the high-throughput-based miRNA identification workflow, after their discovery and before the validation step in an independent series.
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Background: The pharmaceutical industry is in constant development, aiming to increase its portfolio, optimizing time, product quality and efficacy along with patient safety. The main goal of developing and validating an analytica...
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Background: The pharmaceutical industry is in constant development, aiming to increase its portfolio, optimizing time, product quality and efficacy along with patient safety. The main goal of developing and validating an analytical method is to achieve a balance between costs and risks within the wide array of technical possibilities in order to assure that the method is capable of meeting its expectations, ensuring effective quality control. Objective: The objective of this mini-review is to discuss the analytical aspects of development and validation for analysis of pharmaceutical products, focusing on the complete evaluation package in a systematic way to demonstrate the optimal performance of the method. Methods and Results: Validation results are obtained following strict protocols, typically starting with the assessment of selectivity/specificity parameters, followed by parameters such as linearity and precision. Moreover, accuracy, detection limit, quantification limit and method robustness are also evaluated. Conclusion: This paper may serve as a guide for the pharmaceutical-chemical laboratory, conceptualizing quality and current analytical needs, according to Green Analytical Chemistry, for the development and validation of reliable methods, ensuring clarity to the analyst and assisting in decision making.
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