Analytical Characteristics Research Articles

Upconversion-Linked Immunosorbent Assay for the Biomimetic Detection of the Mycotoxin Cyclopiazonic Acid.

The neurotoxin α-cyclopiazonic acid (CPA) is an emerging mycotoxin produced as a secondary metabolite by several fungi species (i.e., Penicillium spp. and Aspergillus spp.). CPA commonly contaminates maize, crops, cheese, and wine. In this work, CPA detection in foodstuff was accomplished by the innovative integration of two strategies: upconversion nanoparticles (UCNPs) and epitope-mimicking peptides, to develop a competitive upconversion-linked immunosorbent assay (ULISA). We have applied UCNPs (type NaYF4:Yb3+, Er3+) as background-free optical labels due to their anti-Stokes shift with excitation in the near-infrared region and emission in the ultraviolet-visible region. Moreover, a CPA epitope-mimicking cyclic peptide (A2) was used as a substitute for the toxin-conjugates traditionally applied to competitive assays. UCNPs were decorated with an anti-CPA fragment antigen-binding antibody (UCNP-Fab), and CPA detection was achieved through competition with a biotinylated CPA epitope-mimicking cyclic peptide (A2-biotin, ACNWWDLTLC-GGGSK (Biotin)-NH2), anchored to a streptavidin-coated microtiter plate, for antibody binding. The ULISA platform offers ultrasensitive detection of CPA (limit of detection of 1.3 pg mL-1 and IC50 value of 15 pg mL-1), and no cross-reactivity was observed with other coproduced mycotoxins. These results substantially outperformed the analytical features of conventional heterogeneous immunoassays based on enzymatic detection. Additionally, the use of advanced computational tools, such as MOE and Alphafold AI, proved advantageous in elucidating the molecular interactions between the antibody and the epitope, providing insights that enhance the rational design of immunoassays. The proposed ULISA was applied to detect CPA in spiked maize samples, and the results were validated by high-performance liquid chromatography coupled to a tandem mass spectrometry detector (HPLC-MS/MS).

In-service teachers’ developing conceptualisations of inquiry in mathematics during a professional development course

ABSTRACT This study follows a group of four secondary school teachers as they participate in various inquiry activities in a one-semester professional development (PD) course in mathematics. Using their discourse as a lens on their conceptualisations of inquiry in mathematics, we report on the development of their conceptualisations throughout the semester. This development seems to be largely related to providing students intellectual space and creating a collaborative learning environment. Exploration and communication foreground their conceptions, while analytical features are more peripheral themes. Throughout the semester, little attention is given in their discourse to mathematical foundations of design elements. We address how the teachers themselves link their development to the PD course. Finally, we discuss findings in light of the PD context and the limited body of research on teacher conceptualisations of inquiry in mathematics, in particular why some features of inquiry appear to be less emphasised in teacher conceptualisations than others.

Polymer-modified screen-printed electrode-based electrochemical sensors for doxorubicin detection

In the last decade, intensive research has been performed in the field of analytical electrochemistry, seeking designs of electrochemical sensors capable of providing better analytical characteristics in terms of sensitivity, selectivity, reliability, ease of fabrication and use, and low cost, especially for pharmaceutical drug monitoring. Our research has primarily focused on developing screen-printed electrode-based sensors and their application as electrochemical platforms for drug determination and monitoring, specifically emphasizing their suitability for surface modification. A commercial screen-printed graphene electrode was used as the electrochemical sensing component, which was subsequently modified with polymers, such as polyvinylidene fluoride and chitosan. All studied electrodes were tested using a doxorubicin hydrochloride (DOX) solution with a concentration of 0.002 mol L-1 dissolved in 0.1 mol L-1 phosphate-buffered saline at pH 6.7. Cyclic voltammetry was used as an electrochemical characterization technique to gather data on all tested electrodes' electrochemical activity. The morphological characterization of the electrodes was done using scanning electron microscopy. The changes in the electrolyte during the electrochemical measurements were followed through ultraviolet-visible spectroscopy. The modified electrodes demonstrated a favorable electrochemical response to DOX and exhibited higher electrical conductivity than the commercial one. The characterization results indicated that the Ch-modified electrode exhibited excellent electrochemical conductivity and demonstrated strong electrochemical performance. The evaluations of this electrode comprised the definition of the lowest limit of detection and limit of quantification among the tested electrodes, with values of 9.822 and 32.741 µmol L-1, respectively, within a linear concentration range from 1.5 to 7.4 µmol L-1. Additionally, the electrodes showed excellent repeatability, stability, and reproducibility, confirming their suitability for sensitive DOX detection.

The influence of students' linguistic condition, school level, and pedagogical input on analytical essay features

IntroductionAnalytical essays are a fundamental discourse practice within educational settings. These essays are topic-oriented texts that aim to inform readers about a specific matter while persuading them of the writer's perspective. This study investigates how students' linguistic condition (monolingual vs. bilingual) affects their ability to meet the social and discursive expectations of analytical essays. This is examined both over a broad developmental span, from elementary to higher education, and microdevelopmentally, through a sequence of genre-oriented classroom activities.MethodsA corpus of 1,179 essays, written by Spanish monolingual and Catalan/Spanish bilingual students across elementary, secondary, and university levels, was analyzed. Participants were tasked with producing texts on both same and different topics. The analysis focused on lexical, syntactic-discursive and structural features identified as indicators of writing proficiency in the Developing Analytical Writing (DAW) model developed in previous studies. Pedagogical input was controlled by the researchers, and an external evaluation of text quality was performed by teachers from the different school levels.ResultsResults indicate that students' linguistic condition influenced most, but not all, the linguistic and structural indicators of writing proficiency but always in interaction with age/school level and pedagogical input. Improvements were observed across school levels and with pedagogical input. Additionally, teachers varied in their appreciation of different facets of writing performance as a function of the participants' age/school level and pedagogical input. However, the linguistic condition of students alone did not significantly impact external evaluations of text quality.DiscussionOur findings reveal a complex interplay between factors such as writers' linguistic condition, their age/school level, and pedagogical input, which jointly shape the quality of analytical essays.

Analytical properties and related inequalities derived from multiplicative Hadamard [formula omitted]-fractional integrals

The present article is intended to address the properties and associated inequalities of multiplicative Hadamard k-fractional integrals. The core concept lies in introducing the multiplicative Hadamard k-fractional integrals. In this framework, various analytical characteristics they possess, such as ∗integrability, continuity, commutativity, semigroup property, boundedness, and others, are examined herein. Subsequently, the Hermite–Hadamard-analogous inequalities are formulated for the novelly constructed operators. Meanwhile, an identity is inferred within multiplicative Hadamard k-fractional integrals, based on which a series of Bullen-type inequalities are derived in this article, where the function Λ∗ is GG-convex and the function (lnΛ∗)s is GA-convex for s>1, with a particular focus on discussing the case when 0<s≤1. To facilitate a more profound understanding of the outcomes, we offer illustrative examples together with numerical simulations to confirm the consistency of the theoretical results. Finally, applications of the proposed results in multiplicative differential equations, quadrature formulas, and special means for real numbers are investigated as well.

Biharmonic slant submanifolds in space forms

In this research work, bi-harmonic slant sub-manifolds in space forms have been studied. Bi-harmonic maps are critical points of the bi-energy functional and are of great importance due to both analytical and geometrical characteristics. After the study of Riemannian Manifolds with complex and contact structure and s-space form structure along with slant sub-manifolds theory, some significant developments related to bi-harmonic slant submanifolds in space forms have been established. Manifolds with constant sectional curvature is known as space form. As s-space form is the generalization of complex and contact structure, we get generalized results. Different aspects of results have discussed.

Voltammetric method for determining hydrazine at a composite polymer-carbon electrode modified with gold particles

Relevance. Hydrazine and its derivatives are used in the production of corrosion inhibitors, medicines, pesticides, dyes, polymers, components of energy production and storage systems, rocket fuels. The prospect of replacing carbon fuels with hydrazine is associated with its high calorific value and the formation of environmentally friendly oxidation end products (nitrogen, water). A serious disadvantage limiting the widespread use of hydrazine is its high toxicity. When exposed to the human and animal body, hydrazine and its compounds have carcinogenic and mutagenic effects, affect the central nervous system, and cause anemia. In this regard, the development of new and improvement of existing methods for the determination of hydrazine and its compounds in environmental objects, technological and biological environments is an urgent task. Aim. To establish the possibility of voltammetric determining hydrazine in solutions using a composite polymer-carbon electrode modified with gold particles. Objects. Solutions of hydrazine salts; aqueous solutions of acids, alkalis and salts. Methods. DC voltammetry, scanning electron microscopy, X-ray spectral microanalysis, computational modeling of ion-molecular equilibria. Results. The oxidation of hydrazine in solutions of N2H4×H2SO4+0.1 М KNO3 on a polymer-carbon electrode modified with gold particles under conditions of voltammetry with linear potential sweep proceeds at potentials E&gt;0.3 V (vs. Ag/AgCl/KCl electrode) with a pronounced maximum current of anodic oxidation in the range of 0.5...0.9 V. Hydrazine oxidation on a modified electrode proceeds at low potentials due to the manifestation of the effect of electrocatalysis. It is established that the delayed stage of the electrode process is single-electron transfer. The reaction is of the first order in terms of hydrazine, is irreversible and is controlled by the diffusion of the substrate to the electrode surface. Based on the results of the analysis of the dependence of the maximum value of the hydrazine oxidation current on the modified electrode on the conditions of voltammetry (solution concentration, potential sweep rate, pH), a method for determining hydrazine in solutions is proposed. The following conditions for recording voltammograms are optimal: nitrogen deaerated background electrolyte 0.1 M KNO3, pH=5...7, the potential range for recording an analytical signal is 0.2...1.0 V, the potential sweep rate is 50 mV/s. Under these conditions, the dependence of the maximum value of the anodic oxidation current on the hydrazine concentration is described by linear regression equations in the ranges of 1×10–5…1×10–4 and 1×10–4…1.5×10–3 M N2H4 (the detection limit is 2.1×10–6 M). In comparison with the electrodes known from the literature, the modified electrode used in the work does not require a costly preparation and storage procedure, according to its analytical characteristics, the proposed method is not inferior to the most highly sensitive electrochemical methods for determining hydrazine.

PERFORMANCE EVALUATION OF OLD VINE VARIETIES IN THE CONTEXT OF ECOPEDOCLIMATIC CHALLENGES AT INCDBH ȘTEFĂNEȘTI, ARGEȘ

This scientific paper analyzes the agrobiological and technological characteristics of the old autochthonous ancestral grapevine varieties, focusing on the specific ecopedoclimatic conditions of the Ștefănești vineyard, Argeș, in the context of contemporary climate challenges. The study conducted in 2024 at INCDBH Ștefănești examined five distinct varieties: Ardeleanca, Coada oilor, Galbenă uriașă, Gordan, and Coarnă neagră. Advanced analytical techniques were applied to assess fertility, facilitating a thorough understanding of agrobiological dynamics. Additionally, technological variables reflecting productivity, yield, and the biochemical traits of the grapes were investigated. The results obtained highlight a significant variability in phenotypic responses, emphasizing the resilience of these ancestral varieties in the face of climatic stress. The correlations identified between analytical characteristics and sensory traits emphasize their relevance in shaping effective strategies for sustainable viticulture. This paper aims not only to rejuvenate interest in the native viticultural heritage but also to promote the integration of these ancestral varieties into the contemporary viticultural landscape, thereby contributing to the development of viable solutions that meet the sustainability requirements of the wine industry.

Physiochemical, Radiative Transitions and Thermoluminescence Characterizations of Nano Ce-doped Monoclinic Barium Titanate

AbstractThis article reports the preparation, analytical, and thermoluminescence (TL) characterization of BaTi5O11 doped with different amounts of Ce. The Sol–gel technique was used to synthesize the doped nanocrystals. The prepared samples were examined by XRD, EDX, UV–Vis spectrophotometry, SEM, and TEM techniques to determine their analytical features. The samples with 0.7% Ce doping showed the best thermoluminescent behavior among the samples we made. The glow curves analysis showed that there were seven peaks that overlapped with each other. The thermal activation energy values of the carrier traps are 0.93, 1.08, 1.16, 1.23, 1.29, 1.35, and 1.38 eV. This study displayed that 0.7% Ce-doped BaTi5O11 can be used in monitoring high doses radiation applications.

Sustainability assessment in food analysis: the application of Green Analytical Chemistry tools to phthalate residue analysis in edible oils

Edible oils are essential in daily diet due to their high contribution of fatty acids, fat-soluble vitamins, and triglycerides. During the processes of growing, processing, storage, transport, or packaging, they can be contaminated by ubiquitous phthalate esters, considered endocrine disruptors. Thus, analytical methodologies to allow tight control of their presence are mandatory. Several sample treatments have been considered in this study: microwave-assisted extraction (MAE), liquid-liquid extraction (LLE), dispersive solid phase extraction (DSPE), magnetic SPE (MSPE), solid phase microextraction (SPME), Surface-enhanced Raman spectroscopy (SERS) or its combinations. However, the selection of an analytical procedure is usually performed from an Analytical Chemistry perspective, without considering factors such as the sustainability of the selected methodology and/or its impact on the environment. In this sense, the Green Analytical Chemistry strategy can play an important role. To demonstrate this fact, six different analytical procedures have been evaluated in terms of sustainability by using several greenness evaluation tools. Procedures from MAE-gel permeation chromatography (GPC)-SPE till SERS, showing adequate analytical characteristics, have been selected. The application of Analytical GREEnness calculator (AGREE), AGREE preparation (AGREE prep), and blue applicability grade index (BAGI) tools showed that MAE-GPC-SPE was the less green analytical procedure while SERS was the greener one. The BAGI evaluation showed that headspace (HS) and SERS were the most applicable procedures.

Analytical Characteristics and Clinical Performance of Anti-Müllerian Hormone Immunoassay on the ADVIA Centaur® System: A Comparison with Other Chemiluminescent Methods

Background: Serum anti-Müllerian hormone (AMH) levels and antral follicle count are key in evaluating ovarian reserve (OR) for fertility. The performance of the Siemens Healthineers AMH assay was assessed on the ADVIA Centaur® System. Methods: Analytical characteristics, clinical performance, and method comparison studies were performed in a prospective cohort of 532 women at fertility clinics. Serum AMH levels were determined using ADVIA Centaur, Beckman Access®, and Roche Elecsys® assays. Results: The limit of quantitation for the ADVIA Centaur AMH assay was 0.030 ng/mL. Repeatability was ≤2.9% CV, within-lab repeatability was ≤3.2% CV, and reproducibility was ≤4.4% CV. Results using serum or lithium heparin sample types were equivalent. Diagnostic sensitivity across assays ranged from 77.3% to 90.2% and specificity ranged from 51.0 to 71.0%; corresponding positive and negative predictive values ranged from 66.6% to 74.3% and 74.2% to 83.0%, respectively. Receiver operating characteristic analyses demonstrated that the assays have a high probability for discriminating between diminished–normal and high OR. ADVIA and Beckman assays agreed according to ADVIA = 1.00 × Beckman + 0.014 ng/mL, τ = 0.909, while a more modest correlation of ADVIA = 1.41 × Roche − 0.024 ng/mL, τ = 0.777 was observed with Roche assay. Conclusions: The ADVIA Centaur assay demonstrates acceptable analytical characteristics and clinical performance comparable to the Roche AMH assay and is essentially interchangeable with the Beckman AMH assay for reliable OR assessment.

Research of Large Inflow Angles BEMT-Based Analytical–Numerical Performance Evaluation Model

This paper presents a comprehensive analytical–numerical algorithm constructed for proprotor performance evaluation, focusing on accommodating large inflow angles. The algorithm’s design, range, and analytical features are clarified, indicating its potential to improve performance analysis, particularly for blades with substantial pitch variations. The Stahlhut model has not been validated against the conventional BEMT small-inflow angle methodology. This paper implements a modified Stahlhut model, coupled with the conventional BEMT. Preliminary validations of the model demonstrate promising results, with deviations reduced to −3% to 4% compared to conventional BEMT methods exhibiting deviations as high as 20% to 88% against experimental data for a highly twisted proprotor. The reconsideration of the computational module carries considerable implications for the design and refinement of proprotors, providing alternative analysis methods that could improve operational effectiveness across a range of flight scenarios. Drawing upon the theoretical framework presented by Stahlhut, the algorithm enables a more complex understanding of proprotor dynamics, facilitating accurate predictions of the loads at each blade section. The introduced algorithm emerges as a valuable asset for evaluating proprotor performance during the early stages of design and certification, offering both low computational cost and medium to high reliability.

Comparison of Two Analytical Techniques of Biomass Burning Markers in PM1 and PM2.5 From Zabrze, Southern Poland.

With increasing attention to alternative energy sources due to environmental concerns, biomass emerges as a promising solution. However, biomass combustion emits particulate matter and harmful substances, impacting air quality and human health. The study compares gas chromatography-mass spectrometry (GC-MS) and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) methods for biomass combustion marker determination. GC-MS involves derivatization and subsequent analysis, while HPAEC-PAD utilizes water extraction, bypassing derivatization. Both methods' analytical performance characteristics were compared, showing HPAEC-PAD to have slightly lower detection limits and simplified sample preparation. The comparison revealed similar concentrations of levoglucosan and mannosan between the methods. However, galactosan (GA) concentrations showed discrepancies, possibly due to method sensitivity and recovery. HPAEC-PAD exhibited advantages in GA detection due to its direct analysis and better recovery. The study highlights the suitability of HPAEC-PAD for biomass combustion marker analysis, especially for GA determination, owing to its simplicity. However, GC-MS offers advantages in complex matrix identification. The findings provide insights for future research on atmospheric aerosol analysis and comparative studies of analytical techniques for other monosaccharides.

Analytical Features Assisted Hierarchical Classification for Automatic Sleep Stage Scoring

Analytical Features Assisted Hierarchical Classification for Automatic Sleep Stage Scoring

Electroextraction of Large Volume Samples Using Paper Points Coupled With Hollow Fiber Membranes: Study of Parameters and Strategies to Enhance Analytical Performance.

Electroextraction (EE) encompasses a range of sample preparation methods whose effectiveness, selectivity, and efficiency are significantly influenced by the physical-chemical characteristics of analytes, samples, and instrumental conditions. This article explores, for the first time, various strategies aimed at enhancing the extraction efficiency of a recent approach of EE utilizing a paper point (PP) combined with a hollow fiber (HF) (abbreviated as PP-HF-EE) to extract various cationic and anionic model compounds from water samples. The study also explores, experimentally, the impact of agitation, organic filter composition, PP diameter, and PP brand on extraction performance, and proves that all these factors are quite important, especially when digital image analysis is utilized for determination. Furthermore, this work demonstrates the ease and feasibility of simultaneously extracting cations and anions using PP-HF-EE and proposes a straightforward method to enhance analyte concentration on the vertex of the PP through a base-to-vertex focusing. Lastly, it is demonstrated, using capillary electrophoresis coupled to a UV-Vis detector, that for PP-HF-EE, the extraction efficiency and pre-concentration factor are less dependent on other parameters when multiple PPs per sample are utilized, with signal enhancement values of up to 111 and 339 for nortriptyline and haloperidol, respectively. All the findings and strategies presented herein constitute significant contributions that can facilitate future research in method development, particularly in the utilization of PP-HF-EE and similar EE approaches.

Retraction Note: Analytic hierarchy process-based automatic feature weight assignment method for content-based satellite image retrieval system

Retraction Note: Analytic hierarchy process-based automatic feature weight assignment method for content-based satellite image retrieval system

A Comprehensive Review of Solitonic Inequalities in Riemannian Geometry

n Riemannian geometry, Ricci soliton inequalities are an important field of study that provide profound insights into the geometric and analytic characteristics of Riemannian manifolds. An extensive study of Ricci soliton inequalities is given in this review article, which also summarizes their historical evolution, core ideas, important findings, and applications. We investigate the complex interactions between curvature conditions and geometric inequalities as well as the several kinds of Ricci solitons, such as expanding, steady, and shrinking solitons. We also go over current developments, unresolved issues, and possible paths for further study in this fascinating area.

Homojunction-Incorporated Oxygen Vacancy Functionalized Spherical TiO2 Nanocrystals for the Electrochemical Detection of Chemical Oxygen Demand.

Chemical oxygen demand (COD) is a critical criterion for the analytical assessment of the degree of organic contaminants in an aqueous system. Typically, toxic and expensive reagents are employed in standardized COD analysis methods, leading to secondary pollution. In this work, we developed a rapid electrochemical method for COD detection based on the oxidation of hydroxyl radicals for organics in water by using oxygen vacancy doped anatase/rutile-TiO2 nanoparticles as electrooxidation catalysts. Homojunction interface generated increasing oxygen vacancies for enhancing electron-transfer rate and accelerating H2O oxidation to substantially improve ·OH yield. Oxygen vacancy further increased the oxygen evolution potential of the material. Initially, glucose was chosen as a standard analyte to evaluate electrochemical responses, and water from urban wastewater treatment plants was assessed as real samples subsequently. Excellent analytical characteristics were achieved with the A/R-TiO2 sensor under the optimal conditions, exhibiting a linear range from 1 to 300 mg L-1 and detection limit of 0.1 mg L-1 COD. The estimated COD values obtained from the samples were highly consistent with those determined using the conventional standard dichromate method. We have presented a fast, cost-effective, and ecologically sustainable method that outperforms the standard COD analysis method and holds great potential for the accurate determination of COD and boasts high detection sensitivity and a broad linear range.

Analysis of multi-term arbitrary order implicit differential equations with variable type delay

Due to their capacity to simulate intricate dynamic systems containing memory effects and non-local interactions, fractional differential equations have attracted a great deal of attention lately. This study examines multi-term fractional differential equations with variable type delay with the goal of illuminating their complex dynamics and analytical characteristics. The introduction to fractional calculus and the justification for its use in many scientific and technical domains sets the stage for the remainder of the essay. It describes the importance of including variable type delay in differential equations and then applying it to model more sophisticated and realistic behaviours of real-world phenomena. The research study then presents the mathematical formulation of variable type delay and multi-term fractional differential equations. The system’s novelty stems from its unique combination of variable delay, generalized multi terms fractional differential operators (n and m), and integral implicit parameters, and studying the stability of the the newly formulated system as compared to the work in the existing literature. While the variable type delay is introduced as a function of time to describe instances where the delay is not constant, the fractional order derivatives are generated using the Caputo approach. The existence, uniqueness, and stability of solutions are the main topics of the theoretical analysis of the suggested differential equations. In order to establish important mathematical features, the inquiry makes use of spectral techniques, and fixed-point theorems. The study finishes by summarizing the major discoveries and outlining potential future research avenues in this developing field. It highlights the potential contribution of multi-term fractional differential equations with variable type delay to improving the control and design of complex systems. Overall, this study adds to the growing body of knowledge in the field of fractional calculus and provides insightful information about the investigation of multi-term fractional differential equations with variable type delay, making it pertinent for academics and practitioners from a variety of fields.

Development and validation of a prediction model for gastric cancer: a single-center prospective study.

This study aimed to develop and validate a novel nomogram for diagnosing gastric cancer (GC). In this prospective analysis, 146 patients of Wenzhou Central Hospital were recruited for a GC group and a benign lesion group and were divided into a training set and an internal validation set in a ratio of 7:3. Clinical and analytical characteristics were collected and analyzed by logistic regression analysis. The performance of the predictive model was evaluated using the receiver operating characteristic curve, calibration curve, and decision curve analysis. There were 5 variables, namely albumin, carcinoembryonic antigen, carbohydrate antigen 125, creatinine, and small proline-rich protein 2A, that were identified as the final parameters for the developed model. In the training and internal validation sets, the area under the curve of the model was 0.968 and 0.979, respectively, showing good diagnostic performance. This study developed and validated a new nomogram based on 5 parameters. This model shows good diagnostic performance in distinguishing GC from benign lesion groups and has certain significance in clinical application.