The thermal demands of flood rescue and impacts on task performance.

The aim of this study was to determine the thermal demand of simulated Flood Rescue tasks and impacts on performance. Ten participants undertook two simulations: 'Cold' (4 °C) -participants stood in knee height moving water (4.8 km·h-1), with simulated wind and rain for 60 min. 'Warm' (20 °C) - participants performed 6x7 min walking in knee height moving water (3.2 km·h-1), pulling 10 kg. Grip strength, manual dexterity, and jump height were measured pre and post. The cold resulted in cooling of the great toe and finger (9.98 [0.84]°C and 10.38 [8.21-12.1] °C, respectively). Jump height, manual dexterity and grip strength fell by 20%, 22% and ∼13%, respectively. In the 'Warm': heart rates were 157 (19) b·min-1, oxygen consumption 30.62 (7.83) mL.kg-1·min-1, and sweat loss 1.06 (0.31) L. There were no differences in the physical tests. Flood Rescue represents significant, but different, challenges. Remaining static in the cold resulted in peripheral neuromuscular cooling, whilst exercising in the warm resulted in a significant thermal challenge. Practitioner Summary: Little is known about the physical requirements, thermal profiles and optimum personal protective equipment for flood rescue. Flood rescue represents significant challenges. In the cold, emergency responders may be incapacitated by peripheral cooling. In the heat, they may be incapacitated by heat-related exhaustion. Consideration should be given to these risks.

Microgrooves with Small Taper Angle Processed by Nanosecond Laser in Closed Flowing Water.

To improve the capability of nanosecond lasers to process structures with a high aspect ratio, a new method of nanosecond laser processing in closed flowing water was proposed in this paper. The microgrooves on a stainless steel 304 surface were processed by the new method, and the influence of processing parameters on the microgrooves was studied. The comparative experiments of laser processing in still water and overflowing water were also carried out, and the unusual phenomenon of laser processing in different flowing water was discovered by a high-speed camera. The results showed that the flowing velocity played a crucial role in underwater laser processing, and that high flowing velocity could timely remove bubbles in closed flowing water, thus obtaining higher processing efficiency. As the depth of the groove increased, the bubbles firstly affected the processing of the sidewall, causing a circular transition between the sidewall and bottom surface. The reflection of the laser beam by the bubble could cause secondary processing on the sidewall, resulting in a decrease in the taper angle. Based on the above research, the microgroove with a width of 0.5 mm, aspect ratio of 3, and taper angle of 87.57° was successfully processed by a nanosecond laser in closed flowing water. Compared to conventional nanosecond laser processing, laser processing in closed flowing water was more advantageous in processing microgrooves with a small taper angle and high aspect ratio.

Streambed immobilization controls the transport of antibiotic resistance genes in flowing water.

Antibiotic resistance is a serious global health issue, resulting in at least 1.2 million deaths in 2019. The environment is a potentially important reservoir of antibiotic resistance; however, the fate of Antibiotic Resistance Genes (ARGs) in the environment remains poorly characterized. One important environmental source of ARGs is manure used as a soil amendment. ARGs from manure may then enter nearby flowing waterbodies, where the factors governing their downstream transport remain unknown. To address this, we conducted experiments by spiking cattle manure in an artificial stream to estimate removal rates (k; m-1) for three ARGs (mefA, tetQ, and tetW) and a ruminant fecal marker (bacR). We then used a Stochastic Mobile-Immobile Model (SMIM) to separate the overall removal into two components, rs, and rh, corresponding to immobilizations in the surface (i.e., water column) and subsurface (i.e., streambed), respectively. Finally, we applied the SMIM across four model streams to predict the downstream travel distance of ARGs and bacR. Our results showed measurable removal for all targets in all experimental replicates (n = 3) and no differences were found in the removal rates among replicates for any target (ANCOVA; p > 0.05). We found that the removal of bacR was significantly lower than tetW (p < 0.05) and slightly lower than mefA (p = 0.088), while tetQ removal was slightly different from tetW's (p = 0.072). We also found that rh values were orders of magnitude larger than rs for ARGs and bacR (t-test; p < 0.05). These findings suggest that ARGs and bacR are being removed from the water column through immobilization reactions occurring in the streambed. Additionally, we predicted that the 90 % removal (or D90) of targets occurs within the first 500 m in all model streams except in a slow-flow pastoral stream, which required 1400 m of downstream transport for 90 % removal. Our findings and model stand out as promising tools to predict the fate of ARGs in streams and will contribute to improving and managing agricultural practices that employ animal manure.

Effect of flowing water on the pharmacokinetic properties of norfloxacin in channel catfish (Ictalurus punctatus) after single-dose oral administration.

BACKGROUND: The recirculating aquaculture system (RAS) is a widely used, water-saving and efficient aquaculture model. However, bacterial diseases are common in farmed fish reared at high densities. Although antibiotics effectively treat these diseases, developing efficient methods to increase drug clearance in fish and decrease the concentrations of antibiotic residues in aquatic products is essential. OBJECTIVES: This study evaluates the effect of flowing water in the RAS on norfloxacin (NOR) pharmacokinetics in channel catfish (Ictalurus punctatus). METHODS: Channel catfish were randomly divided into the control group (RAS group) and the experimental group (flow-through aquaculture system group) (120 individuals/group). A NOR dose of 20 mg/kg was then orally administered to the fish. Plasma, muscle, liver and kidney samples were collected up to 168 h after treatment. NOR concentrations were measured using liquid chromatography-mass spectrometry, and pharmacokinetic parameters were calculated using a non-compartmental method. RESULTS: Flowing water had a significant effect on the plasma pharmacokinetics and tissue distribution of NOR, increasing NOR clearance in the kidney, muscle and plasma. The time to maximum concentration of NOR was shorter in the plasma and longer in the kidney and liver. Moreover, flowing water increased the maximum concentration of NOR in the kidney, muscle and plasma and decreased the area under the concentration-time curve from time 0 to the last measurable concentration in the liver and plasma. Flowing water decreased the withdrawal period in muscle from 10 to 6 days. CONCLUSIONS: These results indicate that flowing water can potentially increase NOR clearance in channel catfish.

Multi-omics integration analysis of long-distance drifting process of green tides in the Yellow Sea simulated in a large-volume flowing water system.

The drifting process of U. prolifera were simulated in a large-volume flowing water system with conditions similar to the field in the Yellow Sea. Biomass and chl-a content per unit of U. prolifera were monitored in the flowing water system by simulating nutrients and temperature variations of seawaters from starting place to terminus of U. prolifera in the South Yellow Sea. According to the variations of nutrients during the drifting process, the floating process can be divided into three stages. Differentially expressed genes and differential metabolites in the three stages of U. prolifera drifting process were identified, which are mainly related to glycometabolism, nitrogen metabolism, and selenium compound metabolism. The process from Stage I to Stage II are mainly related to the translation and molecular function of biological processes, and the main differential metabolites are primary metabolites, whereas, from Stage II to Stage III, secondary metabolites start to increase, indicating that U. prolifera resisted environmental stress by increasing lipids and producing secondary metabolites. It will provide some guidance for the comprehensive interpretation of the biological basis and ecological mechanisms of the large-scale U. prolifera green tides in the Yellow Sea.

A hydroponic plants and biofilm combined treatment system efficiently purified wastewater from cold flowing water aquaculture.

Recently, more and more cold flowing water aquaculture has been adopted, but its wastewater treatment is always ignored, which causes great pressure on the environment. In this study, a compound in-situ treatment system that applied hydroponic plants and biofilm was constructed to treat the wastewater produced by cold flowing water culture of sturgeon. The removal efficiency of the nutrients from culture and the microbial composition in water and biofilm were tested, the correlation between the water quality indexes and bacterium was analyzed, and the abundance of nitrogen and phosphorus cycling genes was quantified. The results show that the system respectively achieved 90%, 100%, 100%, 100% and 48% removal efficiency of NH4+-N, NO3--N, TN, TP and COD which were produced by experimental sturgeon culture. Chinese cabbage (Brassica rapa var. chinensis) and water dropwort (Oenanthe javanica) showed obvious growth in the four plants, which contributed to the removal of nutrients from wastewater. Besides, in the biofilm, Proteobacteria, Bacteroidetes and Verrucomicrobia became the top three dominant flora at the phylum level, and Flavobacterium, Rhodoferax, Sphaerotilus and Chitinimonas became the top four dominant flora at the genus level, which promoted the removal of nitrogen in the wastewater. The FAPROTAX analysis result shows that the highest functions within the carbon and nitrogen metabolisms were significantly identified in the biofilm, such as chemoheterotrophy, aerobic chemoheterotrophy and nitrate reduction. Further, the abundance of denitrifying genes (narG and napA) was higher than the nitrifying related genes (nxrB and amoA), indicating the more active denitrifying process. In summary, the compound in-situ treatment system efficiently removed nutrients from cold flowing water aquaculture. And the combined purification of hydroponic plants and biofilm which is rich in denitrifying bacterium plays an essential role in this process.

Modeling, Validation, and Performance of Two Tandem Cylinder Piezoelectric Energy Harvesters in Water Flow.

This paper studies a novel enhanced energy-harvesting method to harvest water flow-induced vibration with a tandem arrangement of two piezoelectric energy harvesters (PEHs) in the direction of flowing water, through simulation modeling and experimental validation. A mathematical model is established by two individual-equivalent single-degree-of-freedom models, coupled with the hydrodynamic force obtained by computational fluid dynamics. Through the simulation analysis, the variation rules of vibration frequency, vibration amplitude, power generation and the distribution of flow field are obtained. And experimental tests are performed to verify the numerical calculation. The experimental and simulation results show that the upstream piezoelectric energy harvester (UPEH) is excited by the vortex-induced vibration, and the maximum value of performance is achieved when the UPEH and the vibration are resonant. As the vortex falls off from the UPEH, the downstream piezoelectric energy harvester (DPEH) generates a responsive beat frequency vibration. Energy-harvesting performance of the DPEH is better than that of the UPEH, especially at high speed flows. The maximum output power of the DPEH (371.7 µW) is 2.56 times of that of the UPEH (145.4 µW), at a specific spacing between the UPEN and the DPEH. Thereupon, the total output power of the two tandem piezoelectric energy harvester systems is significantly greater than that of the common single PEH, which provides a good foreground for further exploration of multiple piezoelectric energy harvesters system.

Effect of different thawing methods on the quality of mackerel (Pneumatophorus japonicus).

Five thawing methods such as flow water thawing, ultrasonic flowing water thawing, air thawing, microwave thawing and low temperature thawing were used, and the physical, chemical properties and structure of mackerels after thawing were assessed. The results showed that the low temperature thawing had the best water retention, lower protein and fat oxidation. The microwave thawing had the shortest thawing time, but uneven heating leads to partial maturation. Air thawing prolonged exposure to air leads to high levels of protein and fat oxidation. The flow water thawing had better water retention than that of the ultrasonic flowing water thawing, only the thawing time was slightly longer than that of the ultrasonic flowing water thawing. In general, the low temperature thawing performed well after thawing. The flow water thawing used only 1/43 of the low temperature thawing's elapsed time after sacrificing some acceptable qualities. Thus, flow water thawing is more suitable for thawing frozen mackerel.

Very low prevalence of Opisthorchis viverrini s.l. cercariae in Bithynia siamensis siamensis snails from the canal network system in the Bangkok Metropolitan Region, Thailand.

The liver fluke Opisthorchis viverrini s.l. is associated with a long-term public health problem in Thailand. However, O. viverrini s.l. infection in Bithynia snails in the canal network system (CNS) in the Bangkok Metropolitan Region (BMR) has never been assessed. This study aimed to investigate the occurrence of B. siamensis siamensis and the prevalence of O. viverrini s.l. infection in this snail in the CNS in BMR along with morphological examination and molecular analyses on O. viverrini s.l. cercariae. The snails were randomly sampled from the CNS in all BMR areas from January 2018 to July 2019. Snail specimens were identified and examined for digenean infection by shedding and dissection. The cercariae were identified using morphology and molecular methods, including PCR with a species-specific primer and a Bayesian phylogenetic analysis of ITS2 sequences. Bithynia siamensis siamensis was found in almost all sampling localities, with different quantities and detected frequencies. From a total of 7473 B. s. siamensis specimens, O. viverrini s.l. infections were detected in the Northern Bangkok, Muang Nakhon Pathom, Krathum Baen, and Lam Luk Ka areas with an overall prevalence of 0.05% (4/7473) and prevalence of 0.22% (1/455), 0.21% (1/469), 0.40% (1/253), and 0.16% (1/614) in individual localities with positive snails, respectively. This study is the first investigation of digenean infection in the canal network system-type habitat in Thailand and revealed extremely low O. viverrini s.l. prevalence.

TITLE: Très faible prévalence des cercaires d'Opisthorchis viverrini s.l. chez les mollusques Bithynia siamensis siamensis du réseau de canaux dans la région métropolitaine de Bangkok, Thaïlande. ABSTRACT: La douve du foie Opisthorchis viverrini s.l. cause un problème de santé publique récurrent en Thaïlande. L'infection des Bithynia par O. viverrini s.l. dans le réseau de canaux (RC) dans la région métropolitaine de Bangkok (RMB) n'a jamais été évaluée. Cette étude visait à étudier la présence de B. siamensis siamensis et la prévalence de l'infection par O. viverrini s.l. chez ce mollusque dans le RC de la RMB, avec aussi une étude morphologique et des analyses moléculaires sur les cercaires d' O. viverrini s.l. Les mollusques ont été prélevés au hasard dans le RC dans toutes les zones de la RMB de janvier 2018 à juillet 2019. Les spécimens de mollusques ont été identifiés et l'infection par les Digènes a été étudiée par excrétion et dissection. Les cercaires ont été identifiées à l'aide de méthodes morphologiques et moléculaires, y compris la PCR avec une amorce spécifique à l'espèce et une analyse phylogénétique bayésienne des séquences ITS2. Bithynia siamensis siamensis a été trouvé dans presque toutes les localités d'échantillonnage, avec des quantités et des fréquences de détection différentes. Sur un total de 7473 spécimens de B. s. siamensis, des infections par O. viverrini s.l. ont été détectées dans les régions du nord de Bangkok, Muang Nakhon Pathom, Krathum Baen et Lam Luk Ka avec une prévalence globale de 0,05 % (4/7473) et une prévalence respective de 0,22 % (1/455), 0,21 % (1/469), 0,40 % (1/253) et 0,16 % (1/614) dans les localités avec des mollusques positifs. Cette étude est la première enquête sur l'infection des Digènes dans l'habitat de type réseau de canaux en Thaïlande et a révélé une très faible prévalence d'O. viverrini s.l.

Impacts of water temperature on phosphorus release of sediments under flowing overlying water.

River sediment typically acts a 'sink' or 'source' of phosphorus for the overlying water owing to the adsorption of phosphorous by the sediment or release of phosphorous to the water, respectively. In this study, a method is proposed for the determination of the equilibrium concentration of the total phosphorus (ECTP) and total phosphorus release rate (Rr). Phosphorus release experiments were conducted on natural river sediments in flowing water with a low velocity under different water temperatures. An empirical equation was established for the correlation between ECTP and Rr at an arbitrary temperature and at 20 °C. The results indicate that an increase in the water temperature significantly enhances the phosphorus release. In comparison with total phosphorus, dissolved phosphorus and particulate phosphorus in the overlying water do not change with the water temperature. Thus, the results of this study aid in understanding the contaminant exchange between sediments and water in flowing rivers.