Determination of 45 Pesticides in Avocado Varieties by the QuEChERS Method and Gas Chromatography-Tandem Mass Spectrometry.

Gas chromatography (GC) tandem mass spectrometry (MS/MS) stands as a preeminent analytical instrument extensively employed for the surveillance of pesticide residues in food. Nevertheless, these methods are vulnerable to matrix effects (MEs), which can potentially affect accurate quantification depending on the specific combination of analyte and matrix. Among the various strategies to mitigate MEs, matrix-matched calibration represents the prevailing approach in pesticide residue applications due to its cost-effectiveness and straightforward implementation. In this study, a total of 45 representative pesticides were analyzed in three different varieties of avocado (i.e., Criollo, Hass, and Lorena) using the Quick-Easy-Cheap-Effective-Rugged-Safe (QuEChERS) method with ammonium formate and GC-MS/MS. For this purpose, 5 g of the avocado sample was extracted with 10 mL of acetonitrile, and then 2.5 g of ammonium formate was added to induce phase separation. Subsequently, the supernatant underwent a cleanup process via dispersive solid-phase extraction employing 150 mg of anhydrous MgSO4, 50 mg of primary-secondary amine, 50 mg of octadecylsilane, 10 mg of graphitized carbon black, and 60 mg of a zirconium oxide-based sorbent (Z-Sep+). The GC-MS/MS analysis was successfully performed in less than 25 min. Rigorous validation experiments were carried out to assess the performance of the method. The examination of a matrix-matched calibration curve for each variety of avocado revealed that the ME remained relatively consistent and less than 20% (considered as a soft ME) for most pesticide/variety combinations. Furthermore, the method´s limits of quantification were lower than 5 µg/kg for all three varieties. Finally, the recovery values for most pesticides fell within the acceptable range of 70-120%, with relative standard deviation values below 20%.

Implementing best practices on data generation and reporting of Mycobacterium tuberculosis in vitro assays within the ERA4TB consortium.

Tuberculosis (TB) is the historical leading cause of death by a single infectious agent. The European Regimen Accelerator for Tuberculosis (ERA4TB) is a public-private partnership of 30+ institutions with the objective to progress new anti-TB regimens into the clinic. Thus, robust and replicable results across independent laboratories are essential for reliable interpretation of treatment efficacy. A standardization workgroup unified in vitro protocols and data reporting templates. Time-kill assays provide essential input data for pharmacometric model-informed translation of single agents and regimens activity from in vitro to in vivo and the clinic. Five conditions were assessed by time-kill assays in six independent laboratories using four bacterial plating methods. Baseline bacterial burden varied between laboratories but variability was limited in net drug effect, confirming 2.5 µL equally robust as 100 µL plating. This exercise establishes the foundations of collaborative data generation, reporting, and integration within the overarching Antimicrobial Resistance Accelerator program.

Starting from scratch: Step-by-step development of diagnostic tests for SARS-CoV-2 detection by RT-LAMP.

The pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected millions of people worldwide. Public health strategies to reduce viral transmission are based on widespread diagnostic testing to detect and isolate contagious patients. Several reverse transcription (RT)-PCR tests, along with other SARS-CoV-2 diagnostic assays, are available to attempt to cover the global demand. Loop-mediated isothermal amplification (LAMP) based methods have been established as rapid, accurate, point of care diagnostic tests for viral infections; hence, they represent an excellent alternative for SARS-CoV-2 detection. The aim of this study was to develop and describe molecular detection systems for SARS-CoV-2 based on RT-LAMP. Recombinant DNA polymerase from Bacillus stearothermophilus and thermostable engineered reverse transcriptase from Moloney Murine Leukemia Virus were expressed using a prokaryotic system and purified by fast protein liquid chromatography. These enzymes were used to set up fluorometric real time and colorimetric end-point RT-LAMP assays. Several reaction conditions were optimized such as reaction temperature, Tris-HCl concentration, and pH of the diagnostic tests. The key enzymes for RT-LAMP were purified and their enzymatic activity was determined. Standardized reaction conditions for both RT-LAMP assays were 65°C and a Tris-HCl-free buffer at pH 8.8. Colorimetric end-point RT-LAMP assay was successfully used for viral detection from clinical saliva samples with 100% sensitivity and 100% specificity compared to the results obtained by RT-qPCR based diagnostic protocols with Ct values until 30. The developed RT-LAMP diagnostic tests based on purified recombinant enzymes allowed a sensitive and specific detection of the nucleocapsid gene of SARS-CoV-2.

Pesticide-Residue Analysis in Soils by the QuEChERS Method: A Review.

Pesticides are among the most important contaminants worldwide due to their wide use, persistence, and toxicity. Their presence in soils is not only important from an environmental point of view, but also for food safety issues, since such residues can migrate from soils to food. However, soils are extremely complex matrices, which present a challenge to any analytical chemist, since the extraction of a wide range of compounds with diverse physicochemical properties, such as pesticides, at trace levels is not an easy task. In this context, the QuEChERS method (standing for quick, easy, cheap, effective, rugged, and safe) has become one of the most green and sustainable alternatives in this field due to its inherent advantages, such as fast sample preparation, the minimal use of hazardous reagents and solvents, simplicity, and low cost. This review is aimed at providing a critical revision of the most relevant modifications of the QuEChERS method (including the extraction and clean-up steps of the method) for pesticide-residue analysis in soils.

Mechanisms of Friction Reduction in Longitudinal Ultrasonic Surface Haptic Devices With Non-Collinear Vibrations and Finger Displacement.

Friction reduction using ultrasonic longitudinal surface vibration can modify the user perception of the touched surface and induce the perception of textured materials. In the current paper, the mechanisms of friction reduction using longitudinal vibration are analyzed at different finger exploration velocities and directions over a plate. The development of a non-Coulombic adhesion theory based on experimental results is evaluated as a possible explanation for friction reduction with vibrations that are non-collinear with the finger displacement. Comparison with experimental data shows that the model adequately describes the reduction in friction, although it is less accurate for low finger velocities and depends on motion direction.

The Role of Chromatographic and Electromigration Techniques in Foodomics.

Foodomics is the discipline aimed at studying the prevention of diseases by food, identifying chemical, biological and biochemical food contaminants, determining changes in genetically modified foods, identifying biomarkers able to confirm the authenticity and quality of foods or studying the safety, quality and traceability of foods, among other issues. It is mainly based on the use of genomic, transcriptomic, proteomic and metabolomic tools, among others, in order to understand the effect of food on animals and humans at the level of genes, messenger ribonucleic acid, proteins and metabolites. Since the first definition of Foodomics, a reasonable number of works have shown the extremely high possibilities of this discipline, which is highly based on the use of advanced analytical hyphenated techniques - especially for proteomics and metabolomics. This book chapter aims at providing a general description of the role of chromatographic and electromigration techniques that are currently being applied to achieve the main objectives of Foodomics, particularly in the proteomic and metabolomic fields, since most published works have been focused on these approaches, and to highlight relevant applications.

PCA Model of Fundamental Acoustic Finger Force for Out-of-Plane Ultrasonic Vibration and its Correlation with Friction Reduction.

When a finger touches an ultrasonic vibrating plate, a non-sinusoidal contact force is produced. This force is called acoustic finger force. In a setup where closed-loop control is performed on the vibration amplitude, a component of the acoustic finger force can be measured at the fundamental vibration frequency of the plate. This calculation is obtained from the measurement of the variation of the controller voltage between the no-load case and when a finger is present. This calculation is made for a group of twelve participants. From these results a PCA (Principal Component Analysis) model is created. This model permits estimation of the acoustic finger force response of a participant at any vibration amplitude, based on a one or two point measurement. Finally, a linear relation between the PCA coefficients and the friction reduction is proposed. The objective of this relation would be to ultimately provide the means to create an amplitude reference calibration based on the desired friction reduction level, and thus be able to produce a standardized tactile feedback for each user, despite the biomechanical differences in finger pad properties between subjects.

Relationships between Trait Emotional Intelligence, mood states, and future orientation among female Italian victims of Intimate Partner Violence.

OBJECTIVE: Trait Emotional Intelligence (EI) has been associated with psychological outcomes in many conditions; however, it has received little attention in the field of Intimate Partner Violence (IPV). We explored the relationship between trait EI, mood states, and future orientation in a sample of Italian women victims of IPV. METHOD: We recruited 409 help-seeking women who were victims of IPV. They completed the Trait Emotional Intelligence Questionnaire, Positive Affect-Negative Affect Schedule, Long-Term Personal Direction Scale, and Achievability of Future Goals Scale. RESULTS: The results showed that trait EI was associated with the future orientation of IPV victims both directly and indirectly through the mood states. CONCLUSIONS: Our findings suggest potential paths for developing future psychoeducation methodologies designed at improving the quality of life of women IPV victims.

Analysis of phthalic acid esters in sea water and sea sand using polymer-coated magnetic nanoparticles as extraction sorbent.

In this work, poly(dopamine)-coated magnetic nanoparticles (Fe3O4@pDA) have been used as sorbents for the magnetic dispersive solid-phase extraction (m-dSPE) of a group of 10 phthalic acid esters (dipropyl phthalate, DPP, dibutyl phthalate, DBP, dicyclohexyl phthalate, DCHP, bis(2-ethylhexyl)phthalate, DEHP, di-n-octyl phthalate, DNOP, diisodecyl phthalate, DIDP, butylbenzyl phthalate, BBP, diisononyl phthalate, DINP, diisopentyl phthalate, DIPP, di-n-pentyl phthalate, DNPP) and one adipate (di(2-ethylhexyl) adipate, DEHA) from sea water and sea sand extracts employing DBP-d4 and DHP-d4 as internal standards. After m-dSPE, analysis was carried out by gas chromatography mass spectrometry. Mean recovery values (which were determined at three concentration levels) ranged between 70 and 120%, with relative standard deviation values ≤ 20%, for nearly all analytes in both matrices. Matrix-matched calibration curves revealed the presence of matrix effects for certain PAEs, specially for sea sand, though linearity was assayed with determination coefficients (R2) above 0.991 for all target analytes. The limits of quantification of the method were in the range 1.8-319 ng/L for sea water and 0.020-4.0 ng/g for sea sand. Several samples of each type collected at different sites of the coast of Tenerife were also analysed. Only DEHA, DNOP and DIPP were detected in some of the sea sand samples at concentrations ≤ 44 ng/g.

Determination of pesticides in dried minor tropical fruits from Colombia using the Quick, Easy, Cheap, Effective, Rugged, and Safe method-gas chromatography-tandem mass spectrometry.

The AOAC 2007.1 quick, easy, cheap, effective, rugged, and safe official method, together with gas chromatography coupled to a triple quadrupole mass spectrometer was applied for the analysis of 38 multiclass pesticides from dried fruits typically cultivated and exported from Colombia: uchuva (Physalis peruviana), lulo (Solanum quitoense), guanabana (Anona muricata), and pitahaya (Hylocereus undatus). The whole method was validated in terms of matrix-matched calibration, matrix effect, and recovery using atrazine-d5 as internal standard, triphenylphosphate for quality control of the injection, and a proper mixture of analytes protectants. Matrix-matched calibration data were found satisfactory for all pesticides and dried fruits, reporting R2 values above 0.99. Matrix effect values evidenced the existence of such effect in most cases. The applied procedure gave satisfactory recovery percentages (70-120%) and relative standard deviation values (< 20%) for 92% of the 456 combinations pesticide/fruit studied (spiked levels of 25, 200, and 400 µg/kg). Finally, 20 real dried fruit samples were analyzed and residues of tebuconazole were found in two samples of uchuva at a concentration below the lowest calibration level of the method for one of them and at 10.8 ± 1.6 µg/kg for the other, being below or similar to the general maximum residue level established for monitoring purposes in food applications.

Analysis of multiclass pesticides in dried fruits using QuEChERS-gas chromatography tandem mass spectrometry.

In this work, three versions of the QuEChERS method (original, AOAC 2007.01 and CEN 15662) were evaluated for the extraction of 38 multiclass pesticides from a mixture of five dried fruits: (strawberry, blackberry, passion fruit, pineapple and grapes) prior to their gas chromatography tandem mass spectrometry analysis. Among them, the AOAC 2007.01 method provided the best results in terms of lower amount of matrix co-extractives, matrix effect, extraction efficiency and precision. Its application to the analysis of the same pesticides in the individual dried fruits provided good recovery (between 70 and 120%) and relative standard deviation values (<20%) for most pesticides at three spiked levels. Matrix effect assessment revealed the necessity of taking into account such effect. Matrix-matched calibration data were also satisfactory for all analytes and matrices being the R2 ≥ 0.9900 and the lowest calibration level 5 µg/kg, which is lower than the agreed limit set at 10 µg/kg for monitoring purposes in food applications. Three samples of each type were also analysed, finding residues of metalaxyl, chlorpyrifos and iprodione in some of them.

In vitro activity of bedaquiline against slow-growing nontuberculous mycobacteria.

Bedaquiline (BDQ) is a recently approved antibiotic for the treatment of multidrug-resistant tuberculosis, but its potential against slow-growing mycobacteria (SGM) is still unknown. The objective of this study was to determine the in vitro activity of BDQ on SGM by assessing their MIC and minimal bactericidal concentration (MBC). The MIC of BDQ against 17 clinical isolates including Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium chimaera, Mycobacterium kansasii and Mycobacterium simiae species was determined by the resazurin microtitre assay and the MBC by the c.f.u. determination on 7H10 agar plates. BDQ has a bacteriostatic activity on all SGM tested with a MIC range from 0.03 to 0.007 µg ml-1 and surprisingly a good bactericidal activity on the majority of the isolates tested with an MBC of 1-2 µg ml-1 . Based on these preliminary results BDQ seems to be very promising for treatment of diseases caused by SGM.

Cambios en el desempeño de estudiantes de pensamiento matemático desde la evaluación formativa con un banco de preguntas en línea / Changes in the performance of students of a mathematical thinking course through formative assessment with an online question bank

El uso de entornos digitales en línea en la Universidad Jorge Tadeo Lozano ha permitido implementar una base de preguntas con retroalimentación para apoyar al estudiante en el proceso de aprendizaje en la asignatura Pensamiento Matemático. Se desarrolló un proyecto de innovación pedagógica en dos semestres académicos, con el fin de observar si el uso de una base de preguntas con retroalimentación en línea mejora el proceso de apropiación de los conceptos matemáticos de los estudiantes. Las preguntas que conformaron la base se diseñaron siguiendo indicaciones sobre elaboración de preguntas de múltiples opciones con única respuesta; se utilizaron exámenes modelo con los temas vistos en cada uno de los tres momentos en que se divide un periodo académico de la Universidad; dichas evaluaciones formativas fueron puestas a disposición de los estudiantes dos semanas antes de cada evaluación. Debido al carácter del examen -en línea-, con múltiples intentos y accediendo desde cualquier dispositivo, el estudiante podía preparar sus evaluaciones con mayor autonomía y al ritmo que él estableciera. Se realizaron encuestas, entrevistas y grupos focales para identificar algunas características cualitativas que han permitido realizar ajustes y mejoras a la base de preguntas. Los datos obtenidos de cada modelo de examen y los resultados de los estudiantes durante los semestres fueron analizados estadísticamente. Los resultados, tanto cualitativos como cuantitativos, indican que en general, sí hay mejora en el desempeño y apropiación de los conceptos matemáticos en aquellos estudiantes que acceden a los exámenes en línea frente a aquellos que no los usan.

The use of online digital environments at Jorge Tadeo Lozano University has allowed the implementation of a question bank, with feedback, with the purpose of supporting students in their learning process for the subject of Mathematical Thinking; this subject is taught through lectures and workshops that are interrelated and leaded by different professors, one lecture session and two workshop sessions per week. A pedagogical innovation project was developed along two academic periods with the purpose of observing if the use of this online question bank with feedback improved the appropriation of mathematical concepts. The questions that are part of this bank were designed following recommendations for elaborating multiple choice questions with one answer; the selection of distractors for each question was made following conceptual or procedural reasons, which is where most of the difficulties for students are when solving an evaluation on this subject. For each question a detailed description was made, including conceptual aspects and key features such as type of question, question statement, answer choices, reasons for each choice, key information that must be included in feedback (graphics, concepts, solved examples, etc.), cognitive and conceptual domain, level of difficulty, date of elaboration and revision, name of who elaborated the question and name of who reviewed it. Each question was made available on this bank, located at the Virtual Classrooms System at Jorge Tadeo Lozano University (AVATA is the name of this Learning Management System working over Moodle) and corresponding to the Mathematical Thinking course, organized on folders separated by topics and levels of difficulty, according to the available syllabus of the subject. Evaluation models that gathered the topics covered on each of the three segments that form the academic period were used; such formative assessment was made available for students two weeks before each course evaluation. Due to the features of this evaluation, online, with multiple attempts and accessible from multiple devices, students were able to prepare their evaluations with a higher level of autonomy and at the pace, they would establish. Surveys, interviews and focus groups from students and professors that were part of the Mathematical Thinking course were carried out, with the purpose of identifying qualitative features that could eventually lead to adjustments and improvements to the question bank, although not many students participated in these interviews and surveys. Among the qualitative aspects that were highlighted is the fact that students felt comfortable when using this kind of evaluation, as they did not feel the pressure of the results; they also pointed out the role of workshop professors as a motivating element to consult the question bank in order to prepare the evaluations and strengthen mathematical concepts. The data obtained from each evaluation model and the results from students during the academic periods were analyzed statistically, allowing to conclude that there is a significant difference on course grades, both partial and finals, for students who used the evaluation models and students who did not. Results, both qualitative and quantitative, indicated that in general terms there is an improvement in performance for students who access to these online evaluation models compared to students who don't. In order to continue progressing on the work presented here, it is necessary to feed the bank with more questions, considering the aspects indicated from students and professors and also as a way of expanding the possibilities of randomizing the questions as students use the bank. It is also important to carry out statistical analysis to questions, with the purpose of establishing with better precision their levels of difficulty and the levels of difficulty of the evaluation models themselves.

High-throughput analysis of pesticides in minor tropical fruits from Colombia.

In this work, a method has been applied and validated for the determination of a group of 35 multiclass pesticides in the minor tropical fruits rose apple/pomarrosa (Syzygium malaccense), starfruit/carambola (Averrhoa carambola), yoyomo (Spondias purpurea) and papayuela (Vasconcellea pubescens) cultivated and exported in Colombia. The AOAC 2007.1 QuEChERS method, that uses an acetic acid/acetate buffer, was applied together with gas chromatography coupled to a triple quadrupole mass spectrometer. The method was validated in terms of calibration, recovery at three levels of concentration and matrix effects (MEs). A mixture of analyte protectants was also used. A good linearity was obtained in all cases, while the study of the ME revealed the need of developing matrix-matched calibration for many pesticides. Recovery values were in the range 70-120% with relative standard deviation values less than 20% for most of the pesticides studied. The lowest calibration level was 5 µg/kg. Several samples of each type were analysed.

Encapsulation of the HSP-90 Chaperone Inhibitor 17-AAG in Stable Liposome Allow Increasing the Therapeutic Index as Assessed, in vitro, on Leishmania (L) amazonensis Amastigotes-Hosted in Mouse CBA Macrophages.

The current long-term treatment for leishmaniasis causes severe side effects and resistance in some cases. An evaluation of the anti-leishmanial potential of an HSP90-inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), demonstrated its potent effect against Leishmania spp. in vitro and in vivo. We have previously shown that 17-AAG can kill L. (L) amazonensis promastigotes with an IC50 of 65 nM and intracellular amastigote at concentrations as low as 125 nM. As this compound presents low solubility and high toxicity in human clinical trials, we prepared an inclusion complex containing hydroxypropyl-ß-cyclodextrin and 17-AAG (17-AAG:HPßCD) to improve its solubility. This complex was characterized by scanning electron microscopy, and X-ray diffraction. Liposomes-containing 17-AAG:HPßCD was prepared and evaluated for encapsulation efficiency (EE%), particle size, polydispersity index (PDI), pH, and zeta potential, before and after accelerated and long-term stability testing. An evaluation of leishmanicidal activity against promastigotes and intracellular amastigotes of L. (L) amazonensis was also performed. The characterization techniques utilized confirmed the formation of the inclusion complex, HPßCD:17-AAG, with a resulting 33-fold-enhancement in compound water solubility. Stability studies revealed that 17-AAG:HPßCD-loaded liposomes were smaller than 200 nm, with 99% EE. Stability testing detected no alterations in PDI that was 0.295, pH 7.63, and zeta potential +22.6, suggesting liposome stability, and suitability for evaluating leishmanicidal activity. Treatment of infected macrophages with 0.006 nM of 17-AAG:HPßCD or 17-AAG:HPßCD-loaded liposomes resulted in almost complete amastigote clearance inside macrophages after 48 h. This reduction is similar to the one observed in infected macrophages treated with 2 µM amphotericin B. Our results showed that nanotechnology and drug delivery systems could be used to increase the antileishmanial efficacy and potency of 17-AAG in vitro, while also resulting in reduced toxicity that indicates these formulations may represent a potential therapeutic strategy against leishmaniasis.

Antimicrobial activity against Mycobacterium tuberculosis under in vitro lipid-rich dormancy conditions.

Although tuberculosis treatment is dependent on drug-susceptibility testing (DST) and molecular drug-resistance detection, treatment failure and relapse remain a challenge. This could be partially due to the emergence of antibiotic-tolerant dormant mycobacteria, where host lipids have been shown to play an important role. This study evaluated the susceptibility of Mycobacterium tuberculosis to two antibiotic combinations - rifampicin, moxifloxacin, amikacin and metronidazole (RIF-MXF-AMK-MTZ), and rifampicin, moxifloxacin, amikacin and pretomanid (RIF-MXF-AMK-PA) - in a lipid-rich dormancy model. Although their effectiveness in in vitro cultures with dextrose as a carbon source has been proved, we observed that none of the antibiotic mixtures were bactericidal in the presence of lipids. The presence of lipids may confer tolerance to M. tuberculosis against the mixture of antibiotics tested and such tolerance could be even higher during the dormant stages. The implementation of lipids in DST on clinical isolates could potentially lead to a better treatment strategy.

Recent applications of nanomaterials in capillary electrophoresis.

Nanomaterials have found an important place in Analytical Chemistry and, in particular, in Separation Science. Among them, metal-organic frameworks, magnetic and non-magnetic nanoparticles, carbon nanotubes and graphene, as well as their combinations, are the most important nanomaterials that have been used up to now. Concerning capillary electromigration techniques, these nanomaterials have also been used as both pseudostationary phases in electrokinetic chromatography (EKC) and as stationary phases in microchip capillary electrophoresis (CE) and capillary electrochromatography (CEC), as a result of their interesting and particular properties. This review article pretends to provide a general and critical revision of the most recent applications of nanomaterials in this field (period 2010-2017).