Validation Parameters Research Articles

Technical evaluation and standardization of the human thyroid microtissue assay.

The success and sustainability of U.S. EPA efforts to reduce, refine, and replace in vivo animal testing depends on the ability to translate toxicokinetic and toxicodynamic data from in vitro and in silico new approach methods (NAMs) to human-relevant exposures and health outcomes. Organotypic culture models employing primary human cells enable consideration of human health effects and inter-individual variability but present significant challenges for test method standardization, transferability, and validation. Increasing confidence in the information provided by these in vitro NAMs requires setting appropriate performance standards and benchmarks, defined by the context of use, to consider human biology and mechanistic relevance without animal data. The human thyroid microtissue (hTMT) assay utilizes primary human thyrocytes to reproduce structural and functional features of the thyroid gland that enable testing for potential thyroid-disrupting chemicals. As a variable-donor assay platform, conventional principles for assay performance standardization need to be balanced with the ability to predict a range of human responses. The objectives of this study were to (1) define the technical parameters for optimal donor procurement, primary thyrocyte qualification, and performance in the hTMT assay, and (2) set benchmark ranges for reference chemical responses. Thyrocytes derived from a cohort of 32 demographically diverse euthyroid donors were characterized across a battery of endpoints to evaluate morphological and functional variability. Reference chemical responses were profiled to evaluate the range and chemical-specific variability of donor-dependent effects within the cohort. The data-informed minimum acceptance criteria for donor qualification and set benchmark parameters for method transfer proficiency testing and validation of assay performance.

Simultaneous HPLC method development for azelastine HCl and fluticasone propionate nasal spray formulation

Abstract: Azelastine HCl and Fluticasone Propionate nasal spray drug product is commonly used to treat moderate to severe allergic rhinitis and rhino-conjunctivitis. To date, a simultaneous HPLC method for active sub-stances and impurities of this product has not been reported. Acetonitrile and buffer (Octane-1-Sulfonic Acid Sodium Salt and Potassium Dihydrogen Phosphate) were used as a mobile phase. The separation was achieved using Phenomenex Phenyl-hexyl (150 cm × 4.6 mm, 5 µm) column at 1 mL/min flow rate in gradient elution mode. The chromatograms were monitored at 240 nm. The validation parameters such as linearity, limit of quantification, limit of detection, accuracy, precision, robustness and specificity were investigated for the nasal spray. Overall, this study provides valuable insights into the development and validation of an efficient analytical method for assessing the quality and stability of a combination of Azelastine HCl and Fluticasone Propionate nasal spray.

Development and validation of a microwave-assisted digestion technique as a rapid sample preparation method for the estimation of selenium in pharmaceutical dosage forms by ICP-OES.

Selenium is a class 2B element according to the International Council for Harmonization Q3D guidelines. Selenium sulfide is an anti-infective agent with antifungal and antibacterial properties used to treat dandruff and seborrheic dermatitis. The literature survey revealed that most of the analytical techniques to estimate selenium were time-consuming and/or required high skill levels. The process involved identifying the isotopes, selecting the measurement approach, and optimizing a typical microwave-aided digesting procedure. Ammonium hydrogen difluoride, water, and concentrated nitric acid were added to the samples. The confirmed microwave digestion program was a two-step program where in the initial step, the samples were ramped at 200°C for 20 min and held for 5 min. Later, samples were cooled and neutralized by boric acid, then ramped for 20 min to a temperature of 180°C and held for 10 min. Selenium was estimated at 196.090 nm by inductively coupled plasma optical emission spectroscopy (ICP-OES). System suitability was run before initiating analysis to ensure that system performance was consistent. Analytical validation parameters, such as the specificity of the method, were demonstrated at 196.090 nm, linearity was proven from 10 ppm to 150 ppm of selenium concentration, the detection limit was 1.28 ppm, and the limit of quantification was 3.89 ppm. Robustness was confirmed for small changes to ICP-OES operating conditions. The precision of the method demonstrated by analyzing the percentage relative standard deviation for six injections was found to be less than 2.0%. Accuracy was confirmed from 10 ppm to 150 ppm, and all the samples were observed to be within the range of 95%-105%. A common microwave-assisted digestion technique was developed and validated as well. The precision, specificity, linearity, accuracy, and robustness of the method for estimating selenium in selenium sulfide drug substances and various pharmaceutical dosage forms were demonstrated. This newly developed microwave-assisted digestion technique has optimum sensitivity and is highly reproducible and time-saving than the existing methods This method can be applied to numerous matrices for a finished dosage of selenium sulfide formulations.

Estimation of river discharge using Monte Carlo simulations and a 1D hydraulic model based on the artificial multi-segmented rating curves at the confluence of two rivers

During extreme floods caused by climate change, reliable flow discharge data are essential for successful reservoir operation to mitigate downstream flood damage. Generally, the flow discharge is computed using the rating curve (RC) established from the relationship between the flow rate and water stage level. Determining the parameters of rating curves is subject to uncertainties related to the difficulties and limitations of flow monitoring in covering a wide range of flow variations. Especially at river confluences, the uncertainties are pronounced when floods occur owing to several factors such as roughness change, backwaters, and levee overflow. The Seomjin River Basin in Korea suffered from flood inundation that occurred at the tributary confluence during an extreme flood in 2020. To identify a reliable flow rate of the main stream and tributary, this study proposes an indirect flow assessment scheme using a 1D hydrodynamic simulation model to find the best simulated water level in an iterative manner based on Monte Carlo (MC) simulations. With a large amount of discharge data generated from random-number combinations, it is possible to obtain the best results automatically by specifying the reliability limitation considering the uncertainty of the predetermined RC parameters associated with the roughness coefficient. Nash Sutcliffe Efficiency (NSE) was incorporated to evaluate the reproduced water level to meet the threshold specified for NSE ≥ 0.75. The simulated flowrates computed from the revised RC and roughness coefficients revealed an error range of 8%–36.6% compared with the design flood. The approach proposed in this study is applicable for determining the valid parameters necessary to create a revised RC at an existing water level gauge station, where the uncertainties of the RC are pronounced, particularly in the vicinity of the channel confluence.

Generation of 3D realistic geological particles using conditional generative adversarial network aided spherical harmonic analysis

The reconstruction of 3D realistic geological particles remains a significant challenge in the field of granular mechanics. Specifically, numerous spherical harmonic (SH) based generation frameworks have been proposed to synthetic new particle shapes retaining majority particle morphology yet having a certain variety. However, given the fact of assuming one or more established distributions or ignoring secondary particle features, the regenerated particles inevitably lose certain diversities. To address this issue, the deep learning method, conditional generative adversarial network (CGAN) was introduced to the SH analysis for particle shape regeneration. Three kinds of sand particles were synthesized and compared with their real mother particle samples concerning the distribution features of SH coefficients and particle shape parameters for validation. Results prove the proposed method has a good reliable and diverse regeneration performance. This approach is promising to facilitate a more reality closer research on 3D particle-related issues in the future.

Antibiotic knowledge assessment questionnaire in undergraduate pharmacy students: A Rasch analysis of validity evidence

Background: Antibiotic knowledge is crucial for undergraduate pharmacy students who are future healthcare professionals. However, a valid and reliable instrument to assess their knowledge is scarce. This study aimed to develop and validate an Antibiotic Knowledge Assessment Questionnaire (AKAQ). Methods: The AKAQ had three domains and 29 items, encompassing general antibiotic knowledge, antibiotic resistance, and antibiotic stewardship. Rasch analysis was used to assess psychometric properties, including validity parameters (item and person fit and structural validity), reliability (person and item reliability, Cronbach’s Alpha value), item-person interaction, and item bias, using differential item functioning (DIF) based on tems. Results: This study included 500 undergraduate pharmacy students from 90 Indonesian universities. The validity of the questionnaire was demonstrated, except for one item. Person means infit and outfit for MNSQ were 1.02 and 0.95, whereas ZSTD were 0.11 and 0.08, respectively. Items means infit and outfit for MNSQ were 1.01 and 0.96, while ZSTD were 0.11 and -0.23. Item and person reliabilities were acceptable at 0.99 and 0.68. Cronbach’s alpha reliability was acceptable at 0.71. Two items were biased by term. Conclusion: The AKAQ is a valid, reliable, and standard instrument for assessing the antibiotic knowledge levels of undergraduate pharmacy students.

Color-Based Object Tracking Using Forward and Inverse Kinematics

Nowadays, the current surge in diverse applications of robotic arms makes comprehending these concepts of paramount importance. Various studies have been conducted on the topic of robotic arms. However, little attention was paid to the coupling relationship between object tracking and kinematics. Therefore, this research paper delves into the intricacies of robotic arm dynamics, with a specific focus on the topics of Forward and Inverse Kinematics, alongside object tracking facilitated by color-based methodologies to deepen foundational insights into robotic arm functionality. Controlling the motion and movement of robotic arms is the initial step. Leveraging the capabilities of cutting-edge technologies such as OpenCV, Armpi, and Hiwonder, it becomes feasible to precisely rotate the servos to user-input degrees and accurately position the arm based on three-dimensional Cartesian coordinates. Additionally, cameras equipped in the system enable photographing and recognizing target objects. By analyzing various positions of the target object, the robotic arm can dynamically adjust multiple servos to maintain the object's relative position. This tracking mechanism relies on the Proportional-Integral-Derivative algorithm, incorporating a minimum valid area parameter to mitigate interferences. Harnessing these algorithms empowers the robotic arm to discern objects based on camera-detected colors, and is affected slightly by different angles or distances, meaning the system's error margin consistently resides within a favorable interval. The approach exhibits practical utility in daily life scenarios, such as drug classification and recognition.

Evaluation of an Oral Fluid Collection Device and a Solid-Phase Extraction Method for the Determination of Coca Leaf Alkaloids by Gas Chromatography-Mass Spectrometry.

Some South American countries have ancient traditions that may pose legal problems, such as the consumption of coca leaves, as this can provide positive results for cocaine use after the analysis of biological samples. For this reason, it is necessary to find specific markers that help differentiate legal from illegal consumption, such as tropacocaine, cinnamoylcocaine, and especially hygrine and cuscohygrine. In this work, two techniques for collecting biological samples are compared: the Quantisal® Oral Fluid collection device and passive drooling. Once the samples were collected, they were subjected to solid-phase extraction for subsequent injection into GC-MS. Different validation parameters included in international guides have been studied to evaluate whether the proposed method is valid for the defined purpose, placing special emphasis on the study of the matrix effect and little value on GC-MS analyses. With respect to this parameter, an increase in the signal was found for CUS and t-CIN, but it was not significant for the rest of the substances studied. The recoveries have varied significantly depending on the way of working, being higher when working with standardized areas. After carrying out work with the oral fluid samples collected from laboratory volunteers, the method was applied to two real samples. The results obtained support the need for further research to overcome certain limitations presented by the device.

α-particle preformation factors in heavy and superheavy nuclei* *Supported in part by the National Natural Science Foundation of China (12175100, 11975132), the Construct Program of the Key Discipline in Hunan Province, the Research Foundation of Education Bureau of Hunan Province, China (21B0402, 18A237, 22A0305), the Natural Science Foundation of Hunan Province, China (2018JJ2321), the Innovation Group of Nuclear and Particle

In this study, α-particle preformation factors in heavy and superheavy nuclei from 220Th to 294Og are investigated. By combing experimental α decay energies and half-lives, the α-particle preformation factors are extracted from the ratios between theoretical α decay half-lives calculated using the Two-Potential Approach (TPA) and experimental data. We find that the α-particle preformation factors exhibit a noticeable odd-even staggering behavior, and unpaired nucleons inhibit α-particle preformation. Moreover, we find that both the α decay energy and mass number of parent nucleus exhibit considerable regularity with the extracted experimental α-particle preformation factors. After considering the major physical factors, we propose a local phenomenological formula with only five valid parameters for α-particle preformation factors . This analytic expression has a clear physical meaning as well as good precision. As an application, this analytic formula is extended to estimate the α-particle preformation factors and further predict the α decay half-lives for unknown even-even nuclei with Z = 118 and 120.

3D-printed extraction devices fabricated from silica particles suspended in acrylate resin

In recent years, there has been an increasing worldwide interest in the use of alternative sample preparation methods. Digital light processing (DLP) is a 3D printing technique based on using UV light to form photo-curable resin layer upon layer, which results in a printed shape. This study explores the application of this technique for the development of novel drug extraction devices in analytical chemistry. A composite material consisting of a photocurable resin and C18-modified silica particles was employed as a sorbent device, demonstrating its effectiveness in pharmaceutical analysis. Apart from estimating optimal printing parameters, microscopic examination of the material surface, and sorbent powder to resin ratio, the extraction procedure was also optimised. Optimisation included the type and amount of sample matrix additives, desorption solvent, sorption and desorption times, and proper number of sorbent devices needed in extraction protocol. To demonstrate this method's applicability for sample analysis, the solid-phase extraction followed by gas chromatography coupled with mass spectrometry (SPE-GC–MS) method was validated for its ability to quantify benzodiazepine-type drugs. This evaluation confirmed good linearity in the concentration range of 50–1000 ng/mL, with R2 values being 0.9932 and 0.9952 for medazepam and diazepam, respectively. Validation parameters proved that the presented method is precise (with values ranging in-between 2.98 %-7.40 %), and accurate (88.81 % to 110.80 %). A negative control was also performed to investigate possible sorption properties of the resin itself, proving that the addition of C18-modified silica particles significantly increases the extraction efficiency and repeatability.The cost-effectiveness of this approach makes it particularly advantageous for single-use scenarios, eliminating the need for time-consuming sorbent-cleaning procedures, common in traditional solid-phase extraction techniques. Future optimisation opportunities include refining sorbent size, shape, and geometry to achieve lower limits of quantification. As a result of these findings, 3D-printed extraction devices can serve as a viable alternative to commercially available SPE or solid-phase microextraction (SPME) protocols for studying new sample preparation approaches.

Evaluation of Extractants for Determination of Micronutrients in Soils of South Gujarat, India

An experiment was conducted at Department of Soil Science and Agricultural Chemistry, Navsari Agricultural University during the year 2018-19. The methods of micronutrients determination were (i) extracted through diethylene triamine penta acetic acid (DTPA) (ii) extracted through ammonium bicarbonate- diethylene triamine penta acetic acid (AB-DTPA) (iii) extracted through Neubauer. The methods of micronutrients were evaluated through method validation parameters like linearity, sensitivity of instruments, precision and predictability. The available micronutrients determined from the sample soils were correlated with soil physico-chemical properties to know the relationship of these properties with available micronutrients. The linearity study of the series of micronutrients standard were measured through different methods of micronutrient determination. These measured values showed linear relationship with reference values. The coefficient of determination (R2) for all the methods was > 0.90. The precision was determined by relative standard deviation (RSD) (%) of different micronutrient methods which were in the range of 1.834 to 19.11 %. All the studied methods of copper, iron, zinc and manganese determination, AB-DTPA extractant method has highly significant and positive correlation with nutrient uptake by wheat on Microwave Plasma Atomic Emission Spectroscopy (MP-AES) instrument. Organic C and sand content of soil have positive correlation with micronutrients availability. While pH, EC, CEC, CaCO3, silt and clay content of soil have negative correlation with available micronutrients.

Characterization of Walking in Mild Parkinson's Disease: Reliability, Validity and Discriminant Ability of the Six-Minute Walk Test Instrumented with a Single Inertial Sensor.

Although the 6-Minute Walk Test (6MWT) is among the recommended clinical tools to assess gait impairments in individuals with Parkinson's disease (PD), its standard clinical outcome consists only of the distance walked in 6 min. Integrating a single Inertial Measurement Unit (IMU) could provide additional quantitative and objective information about gait quality complementing standard clinical outcome. This study aims to evaluate the test-retest reliability, validity and discriminant ability of gait parameters obtained by a single IMU during the 6MWT in subjects with mild PD. Twenty-two people with mild PD and ten healthy persons performed the 6MWT wearing an IMU placed on the lower trunk. Features belonging to rhythm and pace, variability, regularity, jerkiness, intensity, dynamic instability and symmetry domains were computed. Test-retest reliability was evaluated through the Intraclass Correlation Coefficient (ICC), while concurrent validity was determined by Spearman's coefficient. Mann-Whitney U test and the Area Under the receiver operating characteristic Curve (AUC) were then applied to assess the discriminant ability of reliable and valid parameters. Results showed an overall high reliability (ICC ≥ 0.75) and multiple significant correlations with clinical scales in all domains. Several features exhibited significant alterations compared to healthy controls. Our findings suggested that the 6MWT instrumented with a single IMU can provide reliable and valid information about gait features in individuals with PD. This offers objective details about gait quality and the possibility of being integrated into clinical evaluations to better define walking rehabilitation strategies in a quick and easy way.

How can organizations measure the integration of environmental, social, and governance (ESG) criteria? Validation of an instrument using item response theory to capture workers' perception

AbstractEvaluation of corporate sustainability parameters has become part of organizational management. Item Response Theory (IRT) serves as a valuable approach for quantifying and exploring observable variables associated with these parameters. Therefore, this article aims to propose, apply, and validate an instrument utilizing IRT to measure environmental, social, and governance (ESG) impacts on corporate sustainability performance, using the perspective of workers. Workers were chosen as key stakeholders for the present study, as they were pointed by previous research as central to corporate sustainability decisions. The present paper addresses a literature gap by introducing, implementing, and validating a research instrument, along with a comparative scale, to assess the effects of integrating ESG criteria on corporate sustainability performance. Workers of two major Brazilian electricity sector companies were respondents for this instrument. Multigroup IRT method was used to assess item discrimination and difficulty levels, and to construct a scale reflecting workers' perceptions of integrating ESG criteria. The questionnaire consisted of 15 items, demonstrating Content Validity Coefficients (CVC) above .97, confirming the instrument's content effectiveness. Cronbach's Alpha and McDonald's Omega were greater than .94 for both companies. Questionnaire items demonstrated satisfactory discrimination ability and varying difficulty levels, resulting in a five‐level scale to gauge the impacts of ESG criteria. This research contributes through the introduction and validation of the research instrument, the latent trait assessment scale, and the evaluation of workers' perceptions regarding ESG criteria impacts on corporate sustainability performance. In conclusion, the proposed instrument showed robust psychometric properties, displaying favorable reliability and validity parameters. It effectively measures the impacts of ESG criteria, providing interpretable levels aligned with the unique characteristics of its constituent items

Bioanalytical methods and extraction techniques for the quantification of hydrochlorothiazide and its pharmaceutical combinations: A comprehensive review

AbstractHydrochlorothiazide has been utilized clinically for the past half-century, which is popularly known as a “water pill” as it produces increased urine output. The advancement of bioanalytical methods brought a dynamic field with exciting opportunities for future research. The current review emphasis the bioanalytical methods employed for the quantitative estimation of Hydrochlorothiazide as monotherapy and its popularly used combinational medications available from 1956 to till date. A fixed dose of 25 mg of hydrochlorothiazide with 43 combinational medications is currently available in the market and these combinations are widely employed in the treatment of hypertensive people; those whose blood pressure does not respond effectively to monotherapy of hydrochlorothiazide and also for the treatment of edema (excess fluid in the body) caused by illness such as heart failure, liver problems, and renal disease. It has been convincingly demonstrated that the combination of any two antihypertensive medications belonging to different groups of the same category, significantly lowers blood pressure, in comparison with the effect produced by increasing the dose of a single medicament. Among the various analytical techniques employed for the estimation of Hydrochlorothiazide, the review portrays that hyphenated technique, in specific liquid chromatography coupled with mass spectroscopy was widely employed. The validation parameters namely linearity, LOD, LOQ for individual drug and their combinations, were successfully calibrated. The effectiveness of analytical approaches was evaluated and enhanced for chemical factors. The involvement of green chemistry in the optimized methods for the evaluation of Hydrochlorothiazide for the future development, are suggested.

The difference of model robustness assessment using cross‐validation and bootstrap methods

AbstractThe validation principles on Quantitative Structure Activity Relationship issued by Organization for Economic and Co‐operation and Development describe three criteria of model assessment: goodness of fit, robustness and prediction. In the case of robustness, two ways are possible as internal validation: bootstrap and cross‐validation. We compared these validation metrics by checking their sample size dependence, rank correlations to other metrics and uncertainty. We used modeling methods from multivariate linear regression to artificial neural network on 14 open access datasets. We found that the metrics provide similar sample size dependence and correlation to other validation parameters. The individual uncertainty originating from the calculation recipes of the metrics is much smaller for both ways than the part caused by the selection of the training set or the training/test split. We concluded that the metrics of the two techniques are interchangeable, but the interpretation of cross‐validation parameters is easier according to their similar range to goodness‐of‐fit and prediction metrics. Furthermore, the variance originating from the random elements of the calculation of cross‐validation metrics is slightly smaller than those of bootstrap ones, if equal calculation load is applied.

Validity of individual self-report oral health measures in assessing periodontitis for causal research applications.

Self-reported measures of periodontitis developed for use in population surveillance are increasingly used in causal research. Numerous studies evaluate the validity of these measures against clinical parameters of periodontitis, yet few include validation parameters outside of multivariable models. Individual item validity is necessary to adequately inform use of these measures in causal research. We used data from the National Health and Nutrition Examination Survey 2011-2014 in which dentate participants completed full-mouth periodontal examinations (N=6966). We evaluated six self-report questionnaire items related to periodontal disease status against periodontitis case definitions developed by the Centers for Disease Control and Prevention and American Academy of Periodontology (CDC-AAP). We estimated the sensitivity and specificity of individual items using severe and moderate-to-severe periodontitis classifications. We additionally combined items to evaluate the validity of joint measures. Sensitivity was highest when measures were evaluated against severe periodontitis. Self-rated oral health of fair/poor demonstrated the highest sensitivity for severe (0.60) and moderate-to-severe periodontitis (0.48). Specificity was highest when evaluated against moderate-to-severe periodontitis, with self-reported history of tooth mobility as the most specific measure (0.87 for severe disease; 0.92 for moderate-to-severe) followed by a history of bone loss (0.88 for severe; 0.91 for moderate-to-severe). Combining questions generally improved specificity at the expense of sensitivity. Our findings related to item-specific validity and the associated clinical profiles facilitate needed considerations for the use of self-reported measures of periodontitis in causal research. Additionally, item-specific validity can be used to inform assessments of misclassification bias within such investigations.

Stress degradation study of Etoricoxib, isolation, and characterization of major degradation impurity by preparative high‐performance liquid chromatography, liquid chromatography‐mass spectrometry, and nuclear magnetic resonance: Validation of ultra‐performance liquid chromatography method

AbstractEtoricoxib (ETO) is a selective cyclooxygenase‐2 inhibitor, used as a nonsteroidal anti‐inflammatory drug. In this study, a detailed investigation was conducted on the degradation behavior of ETO under acidic, basic, neutral, photolytic, oxidative, and thermal degradation conditions as per the International Conference on Harmonization (ICH) guideline Q1A (R2). A gradient “ultra‐performance liquid chromatography (UPLC)” method was developed for separating the degradation products formed under various degradation conditions along with process‐related impurities. Acquity BEH phenyl column was used for the separation of analytes and 0.1% formic acid in water and 0.05% formic acid in acetonitrile:methanol (8:2 %v/v) were used as mobile phase‐A and mobile phase‐B. A major degradant namely, N‐oxide impurity was observed in oxidative degradation along with two minor degradants where N‐oxide was confirmed based on LC‐mass spectrometry (LC‐MS) studies. Further, the major degradant was enriched and isolated using preparative HPLC and the conformation of the N‐oxide impurity was established using nuclear magnetic resonance techniques including two‐dimensional studies and high‐resolution MS. In addition, the method for related substances by UPLC has been validated by considering a major degradant, namely N‐oxide along with process‐related impurities as per the ICH guidelines validation parameters.

Trace detection of perfluorooctanoic acid and perfluorooctane sulfonate in surface sediments using a liquid chromatograph coupled to an electrospray ionization single quadrupole mass spectrometer (LC-ESI–Q-MS)

Poly- and perfluoroalkyl substances (PFAS) are among the pollutants of environmental concern besides pharmaceuticals and personal care products, microplastics, and other persistent organic pollutants. Of all the different PFASs reportedly present in the environment, the most researched are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). In this study, these pollutants were detected using a precise, selective, and sensitive liquid chromatographic-electrospray ionization single quadrupole mass spectrometric (LC-ESI–Q-MS) method within a linear range of 0.002–0.02 μg/mL. The method developed was thereafter validated according to the ICH validation parameters. This method was used to monitor PFOA and PFOS in selected surface sediments collected within the environs of two prominent rivers in the KwaZulu-Natal province of South Africa: Umgeni and Palmiet Rivers. While the PFOA levels varied from not detected to 1.490 ng/g dw, and PFOS levels ranged from 0.206 ng/g dw to 0.426 ng/g dw, the total PFOA and PFOS concentration (∑ PFOA and ∑ PFOS) in the surface sediment samples collected were 7.50 ng/g dw and 2.79 ng/g dw, respectively. The percent positive occurrence of PFOA and PFOS in all the tested sediment samples was 81.8 % and 100 %, respectively. This study becomes an eye opener to the commencement of research works with respect to developing remediation strategies for the removal of PFAS in the environment, especially the African environment.

Efficient and straightforward spectrophotometric analysis of 5-hydroxymethylfurfural (HMF) using citrate@Fe3O4 nanoparticles as an adsorbent

In this study, we developed a spectrophotometry method for the analysis of 5-hydroxymethylfurfuraldehyde (HMF) in pharmaceutical formulations using citrate@Fe3O4 adsorbent. As bare magnetite (Fe3O4) has certain limitations, such as aggregation and oxidation, surface modifications are commonly used to improve its properties. We successfully coated Fe3O4 with sodium citrate to create a magnetic adsorbent for isolating HMF from samples. We confirmed the successful surface coating of Fe3O4 with citrate using Fourier Transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Zeta potential, and scanning electron microscopy (SEM). The high adsorption capacity of citrate@Fe3O4 is due to the abundance of carboxyl and hydroxyl groups on the surface of the adsorbent, making it ideal for HMF extraction. The HMF concentration was then quantified using spectrophotometry.Citrate@Fe3O4 exhibited a high surface area and strong interaction with HMF. We analyzed the individual influential factors affecting the magnetic solid phase extraction (MSPE) setup. Validation parameters were also provided to confirm the reliability of the method. Under optimal parameters, the method exhibited excellent linearity in the range of 0.05–30.00 μg/ml with the lower limit of quantification (LLOQ) of 0.05 μg/ml. Relative standard deviations (RSD) values for precision were better than 10% and the method's trueness were better than 10%. Recoveries were found to be in the range of 85% to 106%, indicating excellent accuracy and reliability. We used this method to identify and measure HMF in six different dextrose pharmaceutical dosage forms as intravenous injectable solutions and three honey samples.

Digital image processing in the determination of glued wood joints behavior

The determination of the efficiency of adhesives applied in glued joints, through the analysis of the percentage of wood failure, is one of the main validation parameters for the quality of gluing techniques and adhesive. However, the subjectivity of the interpretation, performance, and visual acuity of the evaluators makes the methodology subjective. This research aimed to establish a method for evaluating the behavior of the glue line in glued joints, using freely available software and digital camera images. Shear samples of glued joints with polyvinyl acetate - PVAc, resorcinol formaldehyde - RF, and melamine formaldehyde - MF were evaluated using digital images obtained by a 16.1-megapixel camera. The images were pre-processed to enable vectorization in Inkscape software, version 1.1.2. Each image was vectorized and subjected to the measurement of the areas of the generated vector layers (glue line and wood). The validation process was performed by evaluating the accuracy of vectorization. Thus, the photograph of each sample and the vectorized image were imported into ImageJ software, version 1.53. To ensure the reliability of the proposed methodology, statistical analyses of the Kappa coefficient, global accuracy, user, and producer were applied. To evaluate the efficiency of the proposed method in relation to the conventional method provided in ASTM D5266-13, five evaluators analyzed the proportion of bond line and wood failure of the 10 samples submitted to the proposed methodology. Subsequently, a descriptive analysis of the data was carried out to evaluate the variability and subjectivity of the conventional analyses among the evaluators. It is noted that the proposed methodology achieved high efficiency in the analysis of the proportion of glue line and wood, and it can be assured by the accuracy tests performed. The research also showed that there was no agreement among the five evaluators using the conventional method. It is concluded that the proposed methodology meets the research objective, with high levels of accuracy, and confirms the subjectivity of the analyses performed with the conventional methodology. The results underscore the need for objective methodologies, employing computational techniques to reduce subjectivity in adhesive bond failure assessments, enhancing critical decisions in the selection of adhesives for industrial structural applications.