ABSTRACT
In this study, we developed an endoscopic hyperspectral imaging (eHSI) system and evaluated its performance in analyzing tissues within tissue phantoms and orthotopic mouse pancreatic tumor models. Our custom-built eHSI system incorporated a liquid crystal tunable filter. To assess its tissue discrimination capabilities, we acquired images of tissue phantoms, distinguishing between fat and muscle regions. The system underwent supervised training using labeled samples, and this classification model was then applied to other tissue phantom images for evaluation. In the tissue phantom experiment, the eHSI effectively differentiated muscle from fat and background tissues. The precision scores regarding fat tissue classification were 98.3% for the support vector machine, 97.7% for the neural network, and 96.0% with a light gradient-boosting machine algorithm, respectively. Furthermore, we applied the eHSI system to identify tumors within an orthotopic mouse pancreatic tumor model. The F-score of each pancreatic tumor-bearing model reached 73.1% for the KPC tumor model and 63.1% for the Pan02 tumor models. The refined imaging conditions and optimization of the fine-tuning of classification algorithms enhance the versatility and diagnostic efficacy of eHSI in biomedical applications.
ABSTRACT
Microplastics (MPs) are small (< 5 mm) plastic particles that are widely found in marine, freshwater, terrestrial and atmospheric environments. Due to their prevalence and persistence, MPs are considered an emerging contaminant of environmental concern. The separation and quantitation of MPs from freshwater sediments is a challenging and critical issue. It is necessary to identify the fate and sources of MPs in the environment, minimise their release and adverse effects. Compared to marine sediments, standardised methods for extracting and estimating the amount of MPs in freshwater sediments are relatively limited. The present study focuses on MP recovery efficiency of four commonly used salt solutions (NaCl, NaI, CaCl2 and ZnCl2) for isolating MPs during the density separation step from freshwater sediment. Known combinations of artificial MP particles (PS, PE, PVC, PET, PP and HDPE) were spiked into standard river sediment. Extraction using NaI, ZnCl2 and NaCl solutions resulted in higher recovery rates from 37 to 97% compared to the CaCl2 solution (28-83%) and varied between polymer types. Low-density MPs (PE, HDPE, PP and PS) were more effectively recovered (> 87%) than the denser polymers (PET and PVC: 37 to 88.8%) using NaCl, NaI and ZnCl2 solutions. However, the effective flotation of ZnCl2 and NaI solutions is relatively expensive and unsafe to the environment, especially in the context of developing countries. Therefore, considering the efficiency, cost and environmental criteria, NaCl solution was selected. The protocol was then tested by extracting MPs from nine riverine sediment samples from the Red River Delta. Sediments collected from urban rivers were highly polluted by MPs (26,000 MPs items·kg-1 DW) compared to sediments located downstream. Using a NaCl solution was found to be effective in this case study and might also be used in long-term and large-scale MP monitoring programmes in Vietnam.
Subject(s)
Microplastics , Water Pollutants, Chemical , Environmental Monitoring , Geologic Sediments , Plastics , Water Pollutants, Chemical/analysisABSTRACT
Fishborne zoonotic trematode (FZT) parasites are a serious food safety problem in Asian countries because of their tradition of eating raw fish. In northern Vietnam, the prevalence of FZT metacercariae (MC) in wild-caught and cultured fish is quite high. The objective of this study was to assess the risk for acquiring these parasites from raw fish dishes prepared in restaurants. Samples of fish meat (body muscle) and remainder parts (head, gills, fins, skin, and muscle tissue from the tail) were obtained from 39 restaurants located in Nam Dinh province, an area endemic for FZTs, and from 74 restaurants in the capital city of Hanoi. Six species of zoonotic intestinal trematodes were recovered from a total of nine freshwater and brackish water fish species. Overall, the prevalence of MC in meat samples was 6.1% and in remainder samples, 34.9%; freshwater fish were more often infected (39.4%) than brackish water species (16.0%). Dishes from Nam Dinh restaurants were more often infected (11.8%) than those from Hanoi (3.1%). The dominant trematode species, Haplorchis pumilio, exhibited a strong predilection for encystment in remainder fish parts (36.5%) compared with meat (3.9%). The mean density of MC in meat samples overall was low (1.0 to 1.5 MC per 50 g); however, the potential for parasites to accumulate over years of eating raw fish could result in significant clinical disease, as occurs with liver flukes. Also, the high densities of MC in the remainder parts (2.3 to 72.9 MC per 50 g) pose a threat for cross-contamination during dish preparation.
