Selection and use of reference panels: a case study highlighting current gaps in the materials available for foot and mouth disease.

The World Organisation for Animal Health (OIE) Manual of Diagnostic Tests and Vaccines for Terrestrial Animals describes a diverse array of assays that can be used to detect, characterise and monitor the presence of infectious agents of farmed livestock. These methods have been developed in different laboratories, at different times, and often include tests or kits provided by the commercial sector. Reference panels are essential tools that can be used during assay development and in validation exercises to compare the performance of these varied (and sometimes competing) diagnostic technologies. World Organisation for Animal Health Reference Laboratories already provide approved international standard reagents to help calibrate diagnostic tests for a range of diseases, but there remain important gaps in their availability for comparative purposes and the calibration of test results across different laboratories. Using foot and mouth disease (FMD) as an example, this review highlights four specific areas where new reference reagents are required. These are to: reduce bias in estimates of the diagnostic sensitivity and inter-serotypic specificity of tests used to detect diverse strains of FMD virus (FMDV), provide bio-safe positive controls for new point-of-care test formats that can be deployed outside high containment, harmonise FMDV antigens for post-vaccination serology, and address inter-laboratory differences in serological assays used to measure virus-specific FMD antibody responses. Since there are often limited resources to prepare and distribute these materials, sustainable progress in this arena will only be achievable if there is consensus and coordination of these activities among OIE Reference Laboratories.

Le Manuel des tests de diagnostic et des vaccins pour les animaux terrestres de l'Organisation mondiale de la santé animale (OIE) décrit une vaste panoplie d'essais utilisables pour la détection, la caractérisation et la surveillance des agents pathogènes affectant les animaux d'élevage. Ces méthodes ont été mises au point par des laboratoires différents à diverses périodes et intègrent souvent des tests ou des kits fournis par le secteur privé. Les panels de référence sont des outils essentiels aussi bien lors de la conception d'un essai que lors d'exercices de validation, leur but étant alors de comparer les performances de technologies diagnostiques variées (et parfois concurrentes). Les Laboratoires de référence de l'OIE fournissent des réactifs de référence internationaux validés afin d'aider à calibrer les tests de diagnostic pour un certain nombre de maladies animales ; toutefois, on constate que nombre de ces réactifs ne sont pas disponibles pour la comparaison et le calibrage interlaboratoires des résultats de tests. À partir de l'exemple de la fièvre aphteuse, les auteurs soulignent quatre domaines spécifiques pour lesquels il conviendrait de disposer de nouveaux réactifs de référence. Il s'agit des réactifs nécessaires pour : (1) réduire les biais dans l'estimation de la sensibilité diagnostique et de la spécificité pour différents sérotypes des tests utilisés pour détecter diverses souches du virus de la fièvre aphteuse ; (2) fournir des contrôles positifs sûrs au plan biologique pour les nouveaux formats de tests utilisables sur le lieu d'intervention et non plus dans des laboratoires de confinement à haute sécurité ; (3) harmoniser les antigènes du virus de la fièvre aphteuse pour la sérologie post-vaccinale ; (4) résoudre le problème des différences obtenues entre laboratoires lors d'essais sérologiques visant à mesurer la réponse en anticorps spécifiques du virus de la fièvre aphteuse. Compte tenu des ressources souvent limitées consacrées à la préparation et à la distribution de ces réactifs, des progrès durables ne seront obtenus que s'il existe un consensus en la matière et une coordination de ces activités parmi les Laboratoires de référence de l'OIE.

En el Manual de pruebas de diagnóstico y vacunas para los animales terrestres de la Organización Mundial de Sanidad Animal (OIE) se describe todo un conjunto de ensayos que se pueden emplear para detectar y caracterizar agentes infecciosos del ganado doméstico y hacer así controles sistemáticos de su eventual presencia. Estos métodos, concebidos en distintos laboratorios en distintos momentos, suelen acompañarse de pruebas o estuches analíticos que proporcionan empresas privadas. Los paneles de referencia son una herramienta esencial, que se puede emplear durante la concepción de ensayos y en los procesos de validación para comparar el funcionamiento de estas diferentes técnicas de diagnóstico, que a veces compiten unas con otras. Los laboratorios de referencia de la OIE ya facilitan reactivos de referencia internacional aprobados que ayudan a calibrar las pruebas de diagnóstico de una serie de enfermedades, pero todavía hay importantes carencias por lo que respecta a la posibilidad de procurárselos con fines de comparación y a la calibración de los resultados que obtienen diferentes laboratorios. Sirviéndose del ejemplo de la fiebre aftosa, los autores destacan cuatro aspectos específicos para los que hacen falta nuevos reactivos de referencia. Se trata de los siguientes: reducir el sesgo a la hora de calcular la sensibilidad de diagnóstico y la especificidad interserotípica de las pruebas empleadas para detectar diversas cepas del virus de la fiebre aftosa; proporcionar controles positivos que ofrezcan seguridad biológica para nuevos modalidades de ensayo utilizables en el lugar de consulta, esto es, en condiciones que no sean de alta contención; armonizar los antígenos víricos para la práctica de análisis serológicos tras la vacunación; y solventar las diferencias entre laboratorios por lo que respecta a los ensayos serológicos empleados para medir la respuesta de anticuerpos específicos contra el virus de la fiebre aftosa. Dado que suele haber escasos recursos para preparar y distribuir este tipo de material, solo será posible avanzar duraderamente en la materia si los laboratorios de referencia de la OIE consensúan y coordinan estas actividades.

Assessing Effects of Salinity on the Performance of a Low-Cost Wireless Soil Water Sensor.

Low-cost, accurate soil water sensors combined with wireless communication in an internet of things (IoT) framework can be harnessed to enhance the benefits of precision irrigation. However, the accuracy of low-cost sensors (e.g., based on resistivity or capacitance) can be affected by many factors, including salinity, temperature, and soil structure. Recent developments in wireless sensor networks offer new possibilities for field-scale monitoring of soil water content (SWC) at high spatiotemporal scales, but to install many sensors in the network, the cost of the sensors must be low, and the mechanism of operation needs to be robust, simple, and consume low energy for the technology to be practically relevant. This study evaluated the performance of a resistivity-capacitance-based wireless sensor (Sensoterra BV, 1018LE Amsterdam, Netherlands) under different salinity levels, temperature, and soil types in a laboratory. The sensors were evaluated in glass beads, Oso Flaco sand, Columbia loam, and Yolo clay loam soils. A nonlinear relationship was exhibited between the sensor measured resistance (Ω) and volumetric soil water content (θ). The Ω-θ relationship differed by soil type and was affected by soil solution salinity. The sensor was extremely sensitive at higher water contents with high uncertainty, and insensitive at low soil water content accompanied by low uncertainty. The soil solution salinity effects on the Ω-θ relationship were found to be reduced from sand to sandy loam to clay loam. In clay soils, surface electrical conductivity (ECs) of soil particles had a more dominant effect on sensor performance compared to the effect of solution electrical conductivity (ECw). The effect of temperature on sensor performance was minimal, but sensor-to-sensor variability was substantial. The relationship between bulk electrical conductivity (ECb) and volumetric soil water content was also characterized in this study. The results of this study reveal that if the sensor is properly calibrated, this low-cost wireless soil water sensor has the potential of improving soil water monitoring for precision irrigation and other applications at high spatiotemporal scales, due to the ease of integration into IoT frameworks.

Development of Low-Cost Air Quality Stations for Next Generation Monitoring Networks: Calibration and Validation of PM2.5 and PM10 Sensors.

A low-cost air quality station has been developed for real-time monitoring of main atmospheric pollutants. Sensors for CO, CO2, NO2, O3, VOC, PM2.5 and PM10 were integrated on an Arduino Shield compatible board. As concerns PM2.5 and PM10 sensors, the station underwent a laboratory calibration and later a field validation. Laboratory calibration has been carried out at the headquarters of CNR-IBIMET in Florence (Italy) against a TSI DustTrak reference instrument. A MATLAB procedure, implementing advanced mathematical techniques to detect possible complex non-linear relationships between sensor signals and reference data, has been developed and implemented to accomplish the laboratory calibration. Field validation has been performed across a full "heating season" (1 November 2016 to 15 April 2017) by co-locating the station at a road site in Florence where an official fixed air quality station was in operation. Both calibration and validation processes returned fine scores, in most cases better than those achieved for similar systems in the literature. During field validation, in particular, for PM2.5 and PM10 mean biases of 0.036 and 0.598 µg/m³, RMSE of 4.056 and 6.084 µg/m³, and R² of 0.909 and 0.957 were achieved, respectively. Robustness of the developed station, seamless deployed through a five and a half month outdoor campaign without registering sensor failures or drifts, is a further key point.

Investigation of polar organic chemical integrative sampler (POCIS) flow rate dependence for munition constituents in underwater environments.

Munition constituents (MC) are present in aquatic environments throughout the world. Potential for fluctuating release with low residence times may cause concentrations of MC to vary widely over time at contaminated sites. Recently, polar organic chemical integrative samplers (POCIS) have been demonstrated to be valuable tools for the environmental exposure assessment of MC in water. Flow rate is known to influence sampling by POCIS. Because POCIS sampling rates (Rs) for MC have only been determined under quasi-static conditions, the present study evaluated the uptake of 2,4,6-trinitrotoluene (TNT), RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), and 2,4- and 2,6-dinitrotoluenes (DNT), by POCIS in a controlled water flume at 7, 15, and 30 cm/s in 10-day experiments using samplers both within and without a protective cage. Sampling rate increased with flow rate for all MC investigated, but flow rate had the strongest impact on TNT and the weakest impact on RDX. For uncaged POCIS, mean Rs for 30 cm/s was significantly higher than that for 7 cm by 2.7, 1.9, 1.9, and 1.3 folds for TNT, 2,4-DNT, 2,6-DNT, and RDX, respectively. For all MC except RDX, mean Rs for caged POCIS at 7 cm/s were significantly lower than for uncaged samplers and similar to those measured at quasi-static condition, but except for 2,6-DNT, no caging effect was measured at the highest flow rate, indicating that the impact of caging on Rs is flow rate-dependent. When flow rates are known, flow rate-specific Rs should be used for generating POCIS-derived time-averaged concentrations of MC at contaminated sites.

Laboratory calibration of a POCIS-like sampler based on molecularly imprinted polymers for glyphosate and AMPA sampling in water.

For more than 15 years, integrative passive sampling has been successfully used for monitoring contaminants in water, but no passive sampling device exists for strongly polar organic compounds, such as glyphosate. We thus propose a polar organic chemical integrative sampler (POCIS)-like tool dedicated to glyphosate and its main degradation product aminomethylphosphonic acid (AMPA), and describe the laboratory calibration of such a tool for calculating the sampling rates of glyphosate and AMPA. This passive sampler consists of a POCIS with molecularly imprinted polymer as a receiving phase and a polyethersulfone diffusion membrane. The calibration experiment for the POCIS was conducted for 35 days in a continuous water-flow-through exposure system. The calibration results show that the sampling rates are 111 and 122 mL day-1 for glyphosate and AMPA respectively, highlighting the potential interest in and the applicability of this method for environmental monitoring. The influence of membrane porosity on the glyphosate sampling rate was also tested. Graphical Abstract ᅟ.

Comparison of the sampling rates and partitioning behaviour of polar and non-polar contaminants in the polar organic chemical integrative sampler and a monophasic mixed polymer sampler for application as an equilibrium passive sampler.

In this work, Oasis HLB® beads were embedded in a silicone matrix to make a single phase passive sampler with a higher affinity for polar and ionisable compounds than silicone alone. The applicability of this mixed polymer sampler (MPS) was investigated for 34 aquatic contaminants (log KOW -0.03 to 6.26) in batch experiments. The influence of flow was investigated by comparing uptake under static and stirred conditions. The sampler characteristics of the MPS was assessed in terms of sampling rates (RS) and sampler-water partition coefficients (KSW), and these were compared to those of the polar organic chemical integrative sampler (POCIS) as a reference kinetic passive sampler. The MPS was characterized as an equilibrium sampler for both polar and non-polar compounds, with faster uptake rates and a shorter time to reach equilibrium than the POCIS. Water flow rate impacted sampling rates by up to a factor of 12 when comparing static and stirred conditions. In addition, the relative accumulation of compounds in the polyethersulfone (PES) membranes versus the inner Oasis HLB sorbent was compared for the POCIS, and ranged from <1% to 83% depending on the analyte properties. This is indicative of a potentially significant lag-phase for less polar compounds within POCIS. The findings of this study can be used to quantitatively describe the partitioning and kinetic behaviour of MPS and POCIS for a range of aquatic organic contaminants for application in field sampling.

An Innovative Miniature Bite Force Recorder.

In this study, a detailed description of development of a new novel bite force recorder (gnathodynamometer) using solid state components is vividly explained. This state of the art authenticated device can be used to assess the complex function of human bite force, which is the net resultant combination of functional response of various craniomandibular structures consisting of interrelated components, like the muscles of mastication, joints, teeth and the neuromuscular system. The consistency and accuracy of the bite force recorder was reaffirmed by doing a detailed laboratory calibration and clinical testing on 30 adult subjects.