Sampling Points Research Articles

Identifying sources and distribution of organic pollutants in a Moroccan river: Characterization of dissolved organic matter by absorption, excitation–emission fluorescence and chemometric analyses

This study investigates surface water contamination of Ben-Kazza River in Morocco, fed by effluents from an adjacent lagoon-based wastewater treatment plant (WWTP) and seasonally by industrial effluents, and which occasionally serves to irrigate agricultural fields. This study has two purpose: i) to track the main sources of contamination through the evolution of dissolved organic matter (DOM) characteristics along the watercourse, and ii) to characterize the WWTP influents and effluents with a focus on the efficiency of the lagoon treatment. We characterized a total of 495 water samples across the watercourse and from the inlet and outlet of the WWTP, using UV–visible absorption and excitation–emission fluorescence coupled with chemometric analyses. Absorption indicators and fluorescence indices were calculated and compared across sampling points. Results highlight spatial shifts together with temporal changes in DOM. PARAFAC identified components that varied between protein-like, humic-like and anthropogenic-like fluorophores along the river, permitted to trace the anthropogenic components and their sources. The lagoon treatment appeared to better remove fresh organic material than humic material: fluorescence intensity decreased by 68 % for peak T1 and by 22 % for peak C. Maximum fluorescence intensities (Fmax) decreased across all PARAFAC components, leading to more than 55 % reduction of ΣFmax.

Development and Application of a Liquid Sampling Device with Timing, Quantitative and Depth Determination

This thesis describes the development process of a liquid sampling device that can be timed, quantitative, and deep. The structural composition, working principle, and innovative features of the liquid sampling device are introduced, and the application prospects are analyzed. The device has the function of controllable and adjustable sampling point depth and sampling volume, and adopts quantitative collection and collection methods without contact with accessories. The device has a silent function in the sample body, which can realize pre-booking of collection time points and multi-point synchronous collection. Wireless remote control automatic mode is adopted for sending and stopping collection instructions, which can be sent one-to-one or one-to-many at the same time. It provides automation links for water quality monitoring projects and meets the requirements of modern scientific and technological development.

Surveillance of tick-borne pathogens in domestic dogs from Chad, Africa

BackgroundTick-borne pathogens are understudied among domestic animals in sub-Saharan Africa but represent significant threats to the health of domestic animals and humans. Specifically, additional data are needed on tick-borne pathogens in Chad, Africa. Surveillance was conducted among domestic dogs in Chad for selected tick-borne pathogens to measure (1) the prevalence of antibodies against Anaplasma spp., Borrelia burgdorferi, and Ehrlichia spp.; (2) the prevalence of infections caused by Hepatozoon spp., Ehrlichia canis, Anaplasma platys, and Babesia spp.; and (3) associations of pathogens with demographic, spatial, and temporal factors. Blood samples were collected from domestic dogs at three time points (May 2019, November 2019, June 2020) across 23 villages in southern Chad.ResultsOf the 428 dogs tested with the IDEXX SNAP 4Dx test in May 2019, 86% (n = 370, 95% CI = 83–90%) were positive for antibodies to Ehrlichia spp., 21% (n = 88, 95% CI = 17–25%) were positive for antibodies to Anaplasma spp., and 0.7% (n = 3, 95% CI = 0.1–2%) were positive for antibodies to Borrelia burgdorferi. Four different pathogens were detected via PCR. Hepatozoon spp. were most commonly detected (67.2–93.4%, depending on the time point of sampling), followed by E. canis (7.0-27.8%), A. platys (10.1–22.0%), and Babesia vogeli (0.4–1.9%). Dogs were coinfected with up to three pathogens at a single time point, and coinfections were most common in May 2019 compared to November 2019 and May 2020.ConclusionsOverall, this study provides new data about the epidemiology of tick-borne pathogens in domestic dogs in Chad, with potential implications for dog and human health.

POLLUTION OF THE FIFTH CANAL ON THE CRNA RIVER IN THE REGION OF BITOLA

Water is an irreplaceable natural resource. The main goal of this research is to see the pollution of the fifth canal on Crna River in the region of Bitola. As measuring points for sampling for this analysis are: measuring point 1 (Crna River near the village of Novaci), measuring point 2 (fifth canal exit of Bitola), measuring point 3 (fifth canal near the village of Kravari) measuring point 4 (fifth canal before flowing into the Crna River), measuring point 5 (Crna River before being mixed with water from the fifth canal), measuring point 6 (Crna River after mixing with water from the fifth canal) and measuring point 7 (Crna River near the village of Skocivir). Water samples were taken in May and November. To determine the water quality, the following physicochemical parameters were made: turbidity (by turbidimeter), suspended solids, total organic carbon, biological oxygen demand, and dissolved oxygen (determined with UV pastel). From the results, it has been concluded that the highest pollution is in the fifth channel, measuring point 2 for the following parameters in May: turbidity (35.3 mg/L), total organic carbon (210.8 mg/L), suspended solids (77.5 mg/L, and in November164.0 mg/L). Of the measuring points of Crna River, the highest pollution is in measuring point 6 in November: biological oxygen demand (14.5 mg/L), and total organic carbon (13.7 mg/L). That is why it is suggested to purify the wastewater before it is released into the rivers.

Motor imagery EEG signal classification based on deformable convolution v3 and adaptive spatial attention mechanism

This paper is dedicated to solving the issue of insufficient feature extraction and declining model performance in the classification of motor imagery electroencephalogram (EEG) signals. We propose an enhanced ResNet18 neural network model and introduce two pivotal innovations at the model level. Firstly, we present the deformable convolution v3 (DCNv3), an improved convolutional structure that overcomes the limitations of the original deformable convolution. Through unbiased design with center sampling points, DCNv3 achieves more precise feature localization, enhances the model’s representation capability for complex structures, and reduces the risk of overfitting. Simultaneously, it comprehensively captures features in effective information regions, thereby strengthening the model’s generalization ability. Furthermore, this enhancement design also improves computational efficiency, reducing computational and parameter burdens. Secondly, we introduce a novel Adaptive Spatial Attention Mechanism (ASAM) aimed at precisely capturing feature correlations, thereby avoiding information loss. We conducted extensive comparative experiments on publicly available datasets BCI IV dataset 2a, BCI IV dataset 2b, and BCI III dataset 3a, achieving accuracy rates of 91.32%, 92.3%, and 90.47% respectively. Compared to other methods, our approach not only significantly improves the average classification accuracy but also demonstrates remarkable generalization capabilities. These results validate the effectiveness and stability of our method, thereby better meeting the practical application requirements of brain-computer interface technology.

SPATIAL VARIABILITY OF PRODUCTION AND BROMATOLOGICAL COMPOSITION OF Brachiaria AND Panicum ACCORDING TO THE SOIL CHEMICAL ATTRIBUTES IN A SILVIPASTORAL SYSTEM WITH EUCALYPTUS

The variability of the soil chemical attributes in an area where woody crops are integrated with forage is quite complex, so it is important to understand the distribution of these soil attributes and their correlation with the forage yield. This study aimed to analyze the spatial variability of the production and bromatological composition of Brachiaria and Panicum forage species according to the soil chemical attributes when cultivated in a silvopastoral system integrated with eucalyptus to optimize the forage yield and nutritional quality of the forage in this multiple-use system. The study was conducted in the municipality of Ribas do Rio Pardo (MS) in the 2011/2012 crop season, where linear and spatial correlations were analyzed between attributes of eucalyptus, forage plants, and the chemical attributes of a Neossolo Quartzarênico (pH, organic matter (OM) and organic carbon (OC) contents, and carbon stock (CS)) at two soil layers: 0.00-0.10 and 0.10-0.20 m. A geostatistical grid with 72 sample points was used. Spatially, eucalyptus height can be estimated by cokriging with OM, and cellulose by cokriging with pH. OM contents above 6 g cm-3 indicated sites with the highest eucalyptus heights. On the other hand, pH values below 4.3 indicated sites with the highest cellulose content for the forage plants. Using geostatistics is technically feasible for creating specific management zones in the eucalyptus forage silvopastoral system.

Assessing Trace Metal Contamination and Associated Risks in the Kossan River Ecosystem, Southern Côte d'Ivoire

Trace metals accumulate in aquatic systems and can pose a threat to human health and wildlife. In recent decades, human activity has become the main source of metals in the environment. In order to gain a better understanding of metal contamination in Ivorian rivers impacted by human activity, and to help set up a database, we studied the distribution of arsenics (As), cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in the Kossan River. A total of 21 surface water and sediment samples were taken at 7 stations along the River Kossan between March 2019 and July 2020. Total concentrations of the metals were analyzed by atomic absorption spectroscopy (AAS). Carcinogenic and non-carcinogenic risks were assessed in surface water. Contamination indices such as EF, CF; Igeo and PLI were calculated to determine the level of sediment contamination. Ecological risk indices Er and RI were used to assess the potential risks associated with metals. The concentrations of As, Pb, Cd, Cu and Zn found in surface water samples fell within the following ranges: 2.03 - 17.19, 1.752 - 13.264, 0.067 - 0.774, 17.44 - 2369.11 and 136.72 - 3669.37 µg/L, respectively and in sediment: 0.69 - 4.60, 2.10 - 11.30, 0.13 - 5.00, 1.70 - 28.20 and 4.10 - 90.30 µg/g, respectively. The results showed high levels of As, Cu, Pb and Zn contamination in places, above WHO limits. The calculation of non-carcinogenic and carcinogenic risk indices revealed that arsenic and copper can present major health risks for humans through the consumption of water. Cd concentrations exceeded geochemical background values. The results suggest moderate to very severe Cd contamination of the sediments by anthropogenic origin at certain sampling points. In general, the results of the ecological risk indices revealed low to moderate levels of contamination for metals, with the exception of heavy cadmium contamination in the river. The highest concentrations of trace metals were observed in water and sediment samples collected from stations with high anthropogenic pressure. The continuing intensification of human activity may in the long term present a major risk to man and his environment, hence the need to set up a system for monitoring river watercourses and to develop a system for remediating trace metals in river water such as phytoremediation.

Contextualising samples: supporting reference genomes of European biodiversity through sample and associated metadata collection

The European Reference Genome Atlas (ERGA) consortium aims to generate a reference genome catalogue for all of Europe's eukaryotic biodiversity. The biological material underlying this mission, the specimens and their derived samples, are provided through ERGA’s pan-European network. To demonstrate the community’s capability and capacity to realise ERGA’s ambitious mission, the ERGA Pilot project was initiated. In support of the ERGA Pilot effort to generate reference genomes for European biodiversity, the ERGA Sampling and Sample Processing committee (SSP) was formed by volunteer experts from ERGA’s member base. SSP aims to aid participating researchers through (i) establishing standards for and collecting of sample/specimen metadata; (ii) prioritisation of species for genome sequencing; and (iii) development of taxon-specific collection guidelines including logistics support. SSP serves as the entry point for sample providers to the ERGA genomic resource production infrastructure and guarantees that ERGA’s high-quality standards are upheld throughout sample collection and processing. With the volume of researchers, projects, consortia, and organisations with interests in genomics resources expanding, this manuscript shares important experiences and lessons learned during the development of standardised operational procedures and sample provider support. The manuscript details our experiences in incorporating the FAIR and CARE principles, species prioritisation, and workflow development, which could be useful to individuals as well as other initiatives.

Rapid motion planning of manipulator in three-dimensional space under multiple scenes

Most working scenes of industrial robots are static scenes and from a previous static scene to a current static scene is a multi-scene. Finding optimal paths with limited time is difficult for motion planning in a high-dimensional space or in multiple scenes. The low efficiency of motion planning of rapidly-exploring random tree star in high-dimensional spaces, low adaptability of global replanning to multiple scenes are addressed by proposing the local replanning based on goal dynamically-guiding rapidly-exploring random tree star (LR-GD-RRT*). The algorithm contributes to fast path tree exploration and multi-scene motion planning. For path tree exploration, sampling points heuristically generating and new nodes growth by goal dynamically-guiding are proposed to reduce the blind and ineffective searches. Moreover, dynamic adjustment of size of new node neighborhood according to density of the obstacles is proposed to search for more neighbor nodes to optimize the path and also to reduce ineffective computation to improve efficiency. For multi-scene, three steps of trimming, re-exploration, and reconnection for local replanning are proposed. For path tree exploration, simulations in 2D plane, 3D space, and the manipulator show that GD-RRT* improves convergence speed, shortens path length and search time, compared with RRT*. For multi-scene, simulations in 3D space and with the manipulator show that the local replanning of the current scene has both lower path cost and higher planning efficiency compared with the global replanning of the previous scene. Motion of the six-degree-of-freedom robot end in a real scene also verifies the effectiveness of the LR-GD-RRT*.

Estimation of the ecological integrity of the Guadiana River using Partial Least Squares Path Modelling and simulation scenarios

Ecological integrity is fundamental to human life and ecosystems, so its assessment and management are crucial. This concept assesses ecosystem health by examining physico-chemical and biological characteristics, riparian vegetation and macroinvertebrate communities. In recent decades, water resources have undergone significant changes due to various factors that have contributed to the physical, chemical and biological pollution of water. To address this problem, a specific model has been developed using the Partial Least Squares Path Modelling methodology to analyse and quantify the main factors affecting the ecological integrity of the Spanish part of the Guadiana River (Spain). The variables analysed at the different sampling points in the catchment include forest cover, anthropogenic pressure, water quality and biological integrity. Water quality and biological integrity, in turn, constitute the concept of ecological integrity. The model predicts 60.3 % of the physico-chemical water quality and 56.6 % of the biological integrity, showing that ¨Forest cover¨ negatively impacts water quality (W = −0.476) by reducing pollution, while ¨Anthropogenic Pressure¨ positively impacts it (W = 0.680) by increasing pollution. Based on the modelling, three future scenarios were designed, from the lowest to the highest pressure considering changes in riparian forest quality based on QBR and changes in the number of reservoirs: a favourable scenario with high riparian forest quality and no reservoirs; an intermediate scenario with good riparian forest quality and no change in the number of reservoirs; and an unfavourable scenario, characterised by very poor riparian forest quality and an increase in the number of reservoirs. In this context, the importance of the conservation and enhancement of riparian vegetation as a nature-based solution is highlighted, as well as the pressure generated by industrial activity and agricultural practices on the ecological integrity of the study area. The favourable scenario, with very good quality riparian vegetation, improves water quality by up to 85 %, positively impacting the ecological integrity of the river. In contrast, the unfavourable scenario, with extremely degraded riparian forest, would decrease water quality by up to 62 %, negatively affecting ecological integrity. Modelling and future scenarios is an essential tool in the decision-making process to improve environmental governance and water security. In addition, the PLS-PM methodology allows the identification and quantification of relationships between complex variables, providing a solid basis for the design of effective environmental management strategies.

Safe concentration, unsafe effects: Impact of BPA on antioxidant function in the hepatopancreas and ovarian gene expression in oriental river prawns (Macrobrachium nipponense)

This study investigated the effects of Bisphenol A (BPA), a common endocrine-disrupting chemical, on the antioxidant enzyme activities in the hepatopancreas and the expression of genes related to ovarian development in oriental river prawns (Macrobrachium nipponense). The 24hLC50 and 48hLC50 values for BPA were 80.59 mg/L and 63.90 mg/L, respectively, with a safe concentration of 12.06 mg/L. Prawns were exposed to low (4.85 mg/L), safe (12.06 mg/L), and high (30.00 mg/L) concentrations of BPA for 10 days to measure enzyme activities, and for 20 days followed by 7 days in BPA-free water to measure gene expression.Short-term exposure (12 h, 1d, 3d) to low concentration BPA did not significantly affect superoxide dismutase (SOD) activity in the hepatopancreas (P > 0.05), but long-term exposure (6d, 10d) significantly reduced SOD activity (P < 0.05). Catalase (CAT) activity showed no significant changes throughout the low concentration exposure period (P > 0.05). At safe and high concentrations, SOD and CAT activities significantly decreased after 12 h of exposure (P < 0.05).BPA affected heat shock protein 90 (HSP90) expression in the ovary, with low concentration BPA significantly upregulating HSP90 after 1 day (P < 0.05), but returning to normal levels after 10 and 20 days. At the safe concentration, HSP90 was significantly upregulated at all three sampling points (1d, 10d, 20d) (P < 0.05), while high concentration exposure led to significant upregulation only on day 10 (P < 0.05).Low concentration BPA had no significant effect on Cathepsin B (CB) and Cathepsin L (CL) gene expression in the ovaries (P > 0.05). However, safe concentration exposure promoted CB expression on days 1, 10, and 20 (P < 0.05), while high concentration exposure significantly increased CB expression on day 1 (P < 0.05), with levels returning to normal on days 10 and 20. CL expression significantly increased after 20 days of exposure to both safe and high concentrations (P < 0.05). Gene expression levels in the ovaries returned to normal after transfer to BPA-free water, with HSP90 and CB normalizing by day 1, and CL by day 7.These results indicate that even safe concentrations of BPA impose stress on the hepatopancreas and increase the expression of HSP90, CB, and CL genes in the ovaries, affecting ovarian development. And, these effects are reversible within a certain period after the removal of BPA.

Identification of Pops Organic Compounds in Sediment in the Cisangkuy Watershed Using GC-MS Analysis Method

The Cisangkuy Watershed is a tributary of the Upper Citarum River located in the Bandung Basin, West Java. Based one previous research, one organic pollution in the Cisangkuy Watershed is the presence of POPs (Persistent Organic Pollutants) compounds. POPs are organic compounds that can last a very long time in the environment (persistent) and have toxic properties for organisms. This study aims to identify and analyse the organic content of POPs and sediments in the Cisangkuy Watershed, as well as to analyse the source of pollutants and categorise them based on the Stockholm Convention on Persistent Organic Pollutants. Identification of POPs compounds using gas chromatography-mass spectrometry (GC-MS) technique. Sediment sampling was conducted by grab sampling that involved 20 sampling points from upstream to downstream of the Cisangkuy Watershed (CS-1 to CS-20). Samples were collected from 9 sub-districts. The research location shows that the land activities at the sampling point include asphalt hot mix, pharmaceutical, textile, and manufacturing industries. The results showed the presence of 1,2-Benzenedicarboxylic acid, mono (2-ethylhexyl) ester, 4,8,12-Tetradecatrienenitrile, 5,9,13-trimethyl-, and 2-Hexyl-1-octanol compounds at sampling points from upstream to downstream. These compounds were derived from chemical industry effluents, fossil fuel combustion, and agricultural activities. The compounds are classified as ‘industrial waste’ and ‘industrial waste with antibiotic properties’ by the Stockholm Convention on Organic Waste Management.

Evaluation of stress in farmed Atlantic salmon (Salmo salar) using different biological matrices

Atlantic salmon were subjected to an acute crowding scenario, and their subsequent stress responses were observed under three distinct swimming speed/water flow (WF) conditions: 0.5, 1, and 1.5 body lengths per second (BL/s). Feces, dermal mucus, and plasma were collected for analysis at 1, 6, and 24 h (h) post-stress. Additionally, the head kidney and two regions of the brain (pituitary and POA) were collected for transcript expression analysis. Fish swimming at 0.5 BL/s exhibited higher pre-stress (baseline) cortisol levels. Across all groups and matrices, the highest cortisol/cortisol metabolites (CM) levels were observed at the 1 h post-stress sampling point. At 6 h (second sampling time point), a clear decline toward baseline levels were observe in all groups. Significant increases in mean plasma glucose levels were observed at 1 h post-stress for all groups. The mean plasma lactate levels varied based on WF treatments, with a significant increase observed at 1 h only for the 1.5 BL/s group. Additionally, significant decreases in mean plasma lactate were noted at 6 and 24 h post-stress for some groups. The mRNA abundances of the tested genes (star, cyp17a1, hsd11β2, srd5a1) increased following the stress events. These changes were not uniform across all groups and were tissue dependent. In summary, the results indicate that mucus and feces can be used as potentially less invasive matrices than blood for evaluating stress and, consequently, the welfare of Atlantic salmon in captivity.

PSIX-21 Can seeds rich in polyunsaturated fatty acids reduce methane emissions when substituting palm oil on dairy beef calves fed high-concentrate diets? In vitro screening

Abstract The aim of this study was to evaluate the rumen in vitro methane (CH4) production of concentrates feed with a different protein source (PS) replacing partially palm oil by different seeds (SE) rich in polyunsaturated fatty acids (PUFA). Concentrate PS were: T1 = 8% soybean meal; and T2 = 15% dried distillers grain. Palm oil (CTR; 4% and 3.5% for T1 and T2, respectively) was partially substituted (1%) by flax seed (FL; 2.7%), canola seed (CO; 3%) or sunflower seed (SU; 2.3%), thus 8 concentrates were tested. Samples were ground at 1-mm and used in an in vitro digestibility assay. The rumen liquid was obtained at the slaughterhouse. Two incubation sets were done; two sampling points lasted 24 and 48 h to calculate the dry matter (DM) digestibility; a third sampling point lasted 12 d to monitor the CH4 production. Data were analyzed using a mixed effects model. Net volume of CH4 per degraded DM presented a PS effect (P &amp;lt; 0.01); T1 produced greater net volume of CH4 per degraded DM than T2 (8.12 vs. 6.91 ± 0.330 ml/mg, respectively). Furthermore, net volume of CH4 per degraded DM presented a SE effect (P &amp;lt; 0.01); all concentrates with seeds tested reduced the net volume of CH4 per degraded DM compared with CTR, and specifically CO produced lower net volume of CH4 per degraded DM than FL and SU (8.91, 7.47, 6.28, 7.39 ± 0.467 ml/mg; CTR, FL, CO, SU, respectively). In conclusion, the use of flax, canola, or sunflower seeds to partially substitute palm oil in concentrate feed, regardless of its PS, can be potential strategies to reduce rumen CH4 emissions, and seems that canola seed may be the most effective one.

VARIAÇÃO BIOMÉTRICA E REPRODUÇÃO DO BIVALVE Anomalocardia flexuosa (BIVALVIA; VENERIDAE) EM DIFERENTES ÁREAS DE PESCA

The bivalve Anomalocardia flexuosa is one of the main fishing resources utilized in artisanal fishing in northeastern Brazil. The objective of the study was to identify the reproductive and biometric variations in the A. flexuosa shell across different fishing areas in the estuary of the Goiana and Megaó rivers in Northeast Brazil, generating information to support strategies for its conservation. Three bimonthly sampling points were used, with P1 being characterized by manual fishing; P2 by more intensive fishing than P1, with the use of less potent fishing gear; and P3 by high-intensity fishing with tools that enhance the collection capacity, such as long-handled nets. For each specimen collected, shell length, shell height, shell width, total weight wet weight, and meat yield were measured to assess size patterns of the organisms and meat yield. Histological analyses were also conducted to identify the reproductive stages. From the analysis of 5,188 captured specimens, it was observed that with P3 presented the lowest body sizes, possibly reflecting overfishing at the site. Growth models were isometric for shell measurements and negative allometric for the length-weight relationship in P1 and P2, and positive allometric in P3. Photomicrographs were taken of 32 specimens for P1, withe 45% males, 48% females and 7% unidentified; and 25 specimens in P3, 12% males, 52% females and 36% unidentified. Regarding reproductive stages, the most representative were the “maturation” and “mature” stages. Due to the evidence of overfishing in P3 and high potential yield in other points, we highlight the need for efficient management actions that mitigate the impacts of overfishing, such as rotation of fishing areas.

Detecting 3D Salinity Anomalies from Soil Sampling Points: A Case Study of the Yellow River Delta, China

Rapidly capturing the spatial distribution of soil salinity plays important roles in saline soils’ management. Existing studies mostly focus on the macroscopic distribution of soil-salinity changes, lacking effective methods to detect the structure of micro-regional areas of soil-salinity anomalies. To overcome this problem, this study proposes a 3D Soil-Salinity Anomaly Structure Extraction (3D-SSAS) methodology to discover soil-salinity anomalies and step forward in revealing the irregular 3D structure of soil-anomaly salinity areas from limited sampling points. We first interpolate the sampling points to soil voxels using 3D EBK. A novel concept, the Local Anomaly Index (LAI), is developed to identify the candidate soil-salinity anomalies with the greatest amplitude of change. By performing differential calculations on the LAI sequence to determine the threshold, the anomaly candidates are selected. Finally, we adopt 3D DBSCAN to construct anomalous candidates as a 3D soil-salinity anomaly structure. The experimental results from the Yellow River Delta data set show that 3D-SSAS can effectively identify the 3D structure of salinity-anomaly areas, which are highly correlated with the geographical distribution mechanism of soil salinity. This study provides a novel method for soil science, which is conducive to further research on the complex variation process of soil salinity’s spatial distribution.

Lateral flow immunoassay device to detect staphylococcal enterotoxin B (SEB) in durian candy.

Staphylococcal enterotoxin B (SEB), a potent enterotoxin produced by Staphylococcus aureus, has been implicated in incidences of Staphylococcal food poisoning in the Philippines. The use of lateral flow immunoassay devices to detect this toxin in solid food samples, like durian candy, at the point of sampling is constrained by the requirement for sample purification (e.g. centrifugation). This problem is also true with the other applications of LFIA devices on food samples. To overcome this challenge, a lateral flow immunoassay (LFIA) device capable of detecting SEB in unpurified durian candy sample was developed in this study. A modified LFIA device was assembled with three layers of glass fiber pads functioning as sample pads instead of a conventional cellulose fiber pad. Unlike with the cellulose fiber pad, the glass fiber sample pads acted as filter and allowed the flow of a 1:5 dilution of durian candy. The LFIA device applied to spiked 1:5 diluted durian candy samples achieved a visual limit of detection of 5ng/mL for SEB, which is twofold lower than reported for previous LFIA devices designed to detect SEB in food samples.

Uncertainty analysis of FLiNaK thermophysical properties on convective heat transfer characteristics in circular tube

Molten salts have attracted a spate of quantity of interests in energy and chemistry fields due to their large volumetric capacity, and thermodynamic stability at elevated temperature. However, there are significant uncertainties in the physical properties of molten salts, such as density, specific heat capacity, dynamic viscosity, and thermal conductivity, due to inexperienced measurement techniques and technology. These uncertainties could have certain impact on the evaluation of molten salts heat transfer characteristics. Therefore, an uncertainty analysis is performed regarding FLiNaK thermophysical properties on convective heat transfer characteristics in circular tube. Then, a polynomial chaos expansion (PCE) method is performed to study the uncertainty affecting the heat transfer characteristic. In the process of uncertainty analysis, tensor product quadrature nodes are used to calculate representative sample points and reduce computational costs. Three primary physical properties of molten salt are taken into account as the input parameters. The Sobol composition method is also used to analyze the contributions of each parameter to heat transfer. The results of the uncertainty analysis suggest that the uncertainties in dynamic viscosity, thermal conductivity, and specific heat capacity have a significant impact on the heat transfer of molten salt, contributing to 80 %, 14 %, and 6 % of the total variability, respectively. It also suggests that the polynomial chaos expansion methodology is both novel and reliable when applied to uncertainty analysis of molten salt.

Ecological quality of the Jucusbamaba River, a high Andean urban river in northeastern Peru

The Jucusbamaba River, located in the northeastern region of Peru, flows through two towns that use its waters for agricultural activities. However, these activities generate waste discharged back into the river, which is additionally polluted by untreated domestic wastewater discharges. The main objective was to evaluate the ecological quality of this lotic system, analyzing biotic and abiotic parameters during two seasons. The biotic parameters included microinvertebrates and fecal coliforms, while the abiotic parameters encompassed temperature, pH, dissolved oxygen, electrical conductivity, turbidity, total dissolved solids, and biochemical oxygen demand. Six sampling points were established where physicochemical and microbiological parameters were analyzed. Simultaneously, quantitative sampling of macroinvertebrates was carried out at the same points to evaluate their diversity using Shannon- Wiener, Margalef and Simpson indices. The Andean Biotic Index (ABI) and the Biotic Family Index (FBI) were calculated to determine the ecological quality of the river using macroinvertebrates. Finally, the spatio-temporal variation of macroinvertebrate composition and physicochemical and microbiological parameters were analyzed. Very high concentrations of BOD, total dissolved solids, and electrical conductivity were obtained in the dry season, while in the rainy season, they were pH, dissolved oxygen, and turbidity. 12548 individuals from 6 classes, 11 orders, and 26 families were collected. The greatest richness of macroinvertebrate families was found at points 1 and 2, with Trichoptera, Ephemeroptera and Plecoptera individuals predominating. There was evidence of temporal variation in physicochemical and microbiological parameters, as well as in macroinvertebrate composition. It was concluded that the ecological quality of the Jucusbamba River decreases as it follows its course due to anthropic disturbances. This research can be used to develop management plans, awareness-raising, and sanitation measures to ensure the protection and conservation of the Jucusbamaba River.

Physics-Informed Active Learning for Accelerating Quantum Chemical Simulations.

Quantum chemical simulations can be greatly accelerated by constructing machine learning potentials, which is often done using active learning (AL). The usefulness of the constructed potentials is often limited by the high effort required and their insufficient robustness in the simulations. Here, we introduce the end-to-end AL for constructing robust data-efficient potentials with affordable investment of time and resources and minimum human interference. Our AL protocol is based on the physics-informed sampling of training points, automatic selection of initial data, uncertainty quantification, and convergence monitoring. The versatility of this protocol is shown in our implementation of quasi-classical molecular dynamics for simulating vibrational spectra, conformer search of a key biochemical molecule, and time-resolved mechanism of the Diels-Alder reaction. These investigations took us days instead of weeks of pure quantum chemical calculations on a high-performance computing cluster.