Variations and Interseasonal Changes in the Gut Microbial Communities of Seven Wild Fish Species in a Natural Lake with Limited Water Exchange during the Closed Fishing Season.

The gut microbiota of fish is crucial for their growth, development, nutrient uptake, physiological balance, and disease resistance. Yet our knowledge of these microbial communities in wild fish populations in their natural ecosystems is insufficient. This study systematically examined the gut microbial communities of seven wild fish species in Chaohu Lake, a fishing-restricted area with minimal water turnover, across four seasons. We found significant variations in gut microbial community structures among species. Additionally, we observed significant seasonal and regional variations in the gut microbial communities. The Chaohu Lake fish gut microbial communities were predominantly composed of the phyla Firmicutes, Proteobacteria(Gamma), Proteobacteria(Alpha), Actinobacteriota, and Cyanobacteria. At the genus level, Aeromonas, Cetobacterium, Clostridium sensu stricto 1, Romboutsia, and Pseudomonas emerged as the most prevalent. A co-occurrence network analysis revealed that C. auratus, C. carpio, and C. brachygnathus possessed more complex and robust gut microbial networks than H. molitrix, C. alburnus, C. ectenes taihuensis, and A. nobilis. Certain microbial groups, such as Clostridium sensu stricto 1, Romboutsia, and Pseudomonas, were both dominant and keystone in the fish gut microbial network. Our study offers a new approach for studying the wild fish gut microbiota in natural, controlled environments. It offers an in-depth understanding of gut microbial communities in wild fish living in stable, limited water exchange natural environments.

A Watt-Level Pulsed Er:Lu2O3 Laser Based on a TiB2 Saturable Absorber.

TiB2 nanoparticles with a bandgap of 0 eV were prepared, and the corresponding nonlinear optical response at 2.85 µm was investigated. Employing a TiB2 as a saturable absorber, a 2.85 µm pulsed Er:Lu2O3 crystal laser with an average output power of 1.2 W was achieved under a maximum pump power of 9.51 W. Laser pulses with durations of ~203 ns were delivered at a repetition rate of 154 kHz, which corresponds to a pulse energy of ~7.8 µJ and a peak power of 39.3 W. As far as we know, the result represents the highest average output power from all Q-switched Er:Lu2O3 crystal lasers.

Malnutrition and cerebral intraparenchymal damage in patients with thrombosis of dural sinuses and/or cerebral veins.

BACKGROUNDS: Thrombosis of dural sinuses and/or cerebral veins (CVT) is an uncommon form of cerebrovascular disease. Malnutrition is common in patients with cerebrovascular disease, and early assessment of malnutrition and individualized nutritional treatment have been reported to improve functional outcomes of these patients. As for CVT patients, little is known about whether these patients would suffer from malnutrition. Also, the correlation between malnutrition and cerebral intraparenchymal damage (CID) in CVT patients was rarely studied. METHODS: Patients with CVT were retrospectively included in this observational study. Multivariate logistic regressions were used to investigate the effects of nutritional indexes on the risk of CID. Subsequently, we used the independent risk factors to construct the nomogram model, and the consistency index (C-index), calibration curve and decision curve analysis (DCA) to assess the reliability and applicability of the model. RESULTS: A total of 165 patients were included in the final analysis. Approximately 72.7% of CVT patients were regarded as malnourished by our malnutrition screening tools, and malnutrition is associated with an increased risk of CID. Prognostic Nutritional Index (PNI) (OR = 0.873; CI: 0.791, 0.963, p = 0.007) remained as an independent predictor for CID after adjustment for other risk factors. The nomogram model showed that PNI and gender have a great contribution to prediction. Besides, the nomogram model was consistent with the actual observations of CID risk (C-index = 0.65) and was of clinical significance. CONCLUSIONS: We reported that malnutrition, as indicated by PNI, was associated with a higher incidence of CID in CVT patients. Also, we have constructed a nomogram for predicting the risk of CID in these patients.

Lennox-Gastaut syndrome characterized by super-refractory status epilepticus treated with high-dose anesthetics: A case report.

RATIONALE: Super-refractory status epilepticus is a serious illness with high morbidity and mortality, which is defined as an SE that continues or recurs 24 hours or more after the onset of anesthesia. Anesthetic agents can be either pro-convulsant or anticonvulsant or both. PATIENT CONCERNS: Epilepsy occurred at the age of 3 years. At the age of 4 years, generalized tonic-clonic seizure occurred for the first time. The patient was hospitalized at the age of 27 and 28 years for treating status epilepticus. At the age of 33 years, antiepileptic drugs were stopped due to poor appetite. In an early morning, the patient was found delirious with reduced speech. DIAGNOSIS: Occasionally, the patient blinked his eyelids, or deflected his eyeballs to 1 side. When propofol was lowered to 10 mL/H, the epileptic wave reduced obviously. Afterwards, the patient opened his eyes autonomously and his consciousness gradually recovered. The patient could answer questions, and the limbs had voluntary movements. The patient breathing also gradually recovered, and his urine gradually returned to pale yellow from green. After anesthetic was stopped for 10 days, the patient lost his consciousness again. The patient eyes turned upward frequently, which was relieved in 1 to 2 seconds with an attack once every 2 to 5 minutes. INTERVENTIONS: Clonazepam was gradually reduced to 2 mg qn, and the patient gradually woke up during this process. The patient was also treated with levetiracetam 1.5 g bid, oxcarbazepine 0.6 g bid, topiramate 50 mg bid and valproate 0.4 g tid. OUTCOMES: After 1 month follow-up, status epilepticus did not appear again. LESSONS: Propofol aggravated the tonic seizures. As tonic seizures occur during natural sleep and after sleep induced by various narcotic drugs, the decrease of consciousness level induced by excessive sedation of narcotic drugs has been suggested as the reason for poor seizure control.

What makes residents more willing to participate in source separation of waste masks under the COVID-19 pandemic?

With the outbreak of the novel coronavirus (COVID-19), the generation of a large amount of medical waste brought a rude shock to the existing solid waste management system. Since masks constitute the most common household medical waste under the COVID-19 pandemic, their effective collection and treatment can significantly reduce the potential risks for secondary transmission, and this concern has attracted worldwide attention. Taking Macau City as a case study, this research tried to identify factors that can influence residents' behavioral intentions toward the source separation of COVID-19 waste masks. The extended theory of planned behavior (TPB) model is used to examine the influence factors of the source separation behaviors of 510 respondents. The results show that the main factors that positively affected respondents' behavioral intentions toward waste-mask source separation are: cognitive attitude, convenience, and perceived behavioral control, and among these, cognitive attitude has the highest influence. Subjective norm is also proved to be the weak factor to improving behavioral intention. Policy advocacy, and demographic variables have no significant effect on behavioral intention. The results of this study can help decision makers and managers formulate effective strategies to increase residents' participation in the source separation of waste masks. Supplementary Information: The online version contains supplementary material available at 10.1007/s10163-022-01513-7.

Chronological deposition record of trace metals in sediment cores from Chaohu Lake, Anhui Province, China.

Lakes located in the mid-low reaches of the Yangtze River watershed have been subjected to various degrees of human perturbation that would have resulted in toxic metal concentrations and would pose potential risk to the natural habitats. Therefore, in the present study, two sediment cores from Chaohu Lake were collected to determine any such concentration, expressed as the enrichment characteristics of major and trace metals (Al, Fe, Mn, Cu, Pb, Zn, Cr, Cd, As, Hg, and Ni) in response to natural and anthropogenic changes. An approximate 180-year (1840-2021) deposition record of trace metals in sediment cores was obtained on the basis of 137Cs and 210Pb dating. Enrichment factors (EFs) and the geo-accumulation index (Igeo) were adopted to evaluate the enrichment state and pollution status of trace metals. The results showed that Cu and Zn were persistently more enriched in sediment, whereas Mn, Pb, Cd, and Hg has shown remarkable increasing trends in the west lake since the 1970s. Evaluation of the Igeo confirmed that sediment was moderately polluted with Cu and Zn within the whole lake and with Cd in the west lake area, whereas it was uncontaminated with Cr and slightly contaminated with other metals. Furthermore, source identification based on multivariate statistical analysis including correlation analysis, principal component analysis, and cluster analysis suggested similar pollution sources for the studied metals. Combined with the natural and anthropogenic changes within the watershed, enhanced soil erosion due to population expansion and agricultural intensification was a major contributor to sedimentary metals before the 1970s while industrial wastewater, urban runoff, and domestic sewage were predominant inputs of trace metals after the 1970s.

Gene Regulation during Carapacial Ridge Development of Mauremys reevesii: The Development of Carapacial Ridge, Ribs and Scutes.

The unique topological structure of a turtle shell, including the special ribs-scapula relationship, is an evolutionarily novelty of amniotes. The carapacial ridge is a key embryonic tissue for inducing turtle carapace morphologenesis. However, the gene expression profiles and molecular regulatory mechanisms that occur during carapacial ridge development, including the regulation mechanism of rib axis arrest, the development mechanism of the carapacial ridge, and the differentiation between soft-shell turtles and hard-shell turtles, are not fully understood. In this study, we obtained genome-wide gene expression profiles during the carapacial ridge development of Mauremys reevesii using RNA-sequencing by using carapacial ridge tissues from stage 14, 15 and 16 turtle embryos. In addition, a differentially expressed genes (DEGs) analysis and a gene set enrichment analysis (GSEA) of three comparison groups were performed. Furthermore, a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was used to analyze the pathway enrichment of the differentially expressed genes of the three comparative groups. The result displayed that the Wnt signaling pathway was substantially enriched in the CrTK14 vs. the CrTK15 comparison group, while the Hedgehog signaling pathway was significantly enriched in the CrTK15 vs. the CrTK16 group. Moreover, the regulatory network of the Wnt signaling pathway showed that Wnt signaling pathways might interact with Fgfs, Bmps, and Shh to form a regulatory network to regulate the carapacial ridge development. Next, WGCNA was used to cluster and analyze the expression genes during the carapacial ridge development of M. reevesii and P. sinensis. Further, a KEGG functional enrichment analysis of the carapacial ridge correlation gene modules was performed. Interesting, these results indicated that the Wnt signaling pathway and the MAPK signaling pathway were significantly enriched in the gene modules that were highly correlated with the stage 14 and stage 15 carapacial ridge samples of the two species. The Hedgehog signaling pathway was significantly enriched in the modules that were strongly correlated with the stage 16 carapacial ridge samples of M. reevesii, however, the PI3K-Akt signaling and the TGF-ß signaling pathways were significantly enriched in the modules that were strongly correlated with the stage 16 carapacial ridge samples of P. sinensis. Furthermore, we found that those modules that were strongly correlated with the stage 14 carapacial ridge samples of M. reevesii and P. sinensis contained Wnts and Lef1. While the navajo white 3 module which was strongly correlated with the stage 16 carapacial ridge samples of M. reevesii contained Shh and Ptchs. The dark green module strongly correlated with the stage 16 carapacial ridge samples of P. sinensis which contained Col1a1, Col1a2, and Itga8. Consequently, this study systematically revealed the signaling pathways and genes that regulate the carapacial ridge development of M. reevesii and P. sinensis, which provides new insights for revealing the molecular mechanism that is underlying the turtle's body structure.

Bacterial community composition and indicators of water quality in Caizi Lake, a typical Yangtze-connected freshwater lake.

Caizi Lake is an important lake connected to the Yangtze River in Anhui Province and a crucial connection for the Yangtze-to-Huaihe Water Diversion Project. There were marked differences in trophic status of the six sampling sites based on the physicochemical characterization. The Bacterial Eutrophic Index (BEI), used to quantify water quality, was well related to Carlson's trophic state index (TSI) (Spearman's ρ = 0.829, P < 0.05). Mean TSI and BEI were 54 and 0.58, respectively, indicating that Caizi Lake was slightly eutrophic. Actinobacteriota were the predominant bacterial phylum in the water and Acidobacteriota in sediments. The diversity and composition of the bacterial community was markedly different between sites for water but not sediment samples. Unlike other Yangtze-connected freshwater lakes, the distance-based redundancy analysis revealed that dissolved oxygen affected the composition of the planktonic bacterial community (P < 0.001), while total phosphorus was the major factor in the sediments (P < 0.05). The water quality of Caizi Lake has significantly improved since a few years ago. These results contribute to the long-term monitoring of the ecological quality of the water environment along the Yangtze River to the Huaihe River.

Trace metals in sediment from Chaohu Lake in China: Bioavailability and probabilistic risk assessment.

Bioavailability-based probabilistic risk assessment is an effective approach for risk characterization of trace metals towards aquatic species. However, it has not been routinely applied in lake management due to limited research. In this study, Chaohu Lake (Anhui Province, China) was selected as a case study, and total and bioavailable concentrations of trace metals in surface sediment were investigated using chemical extraction and diffusive gradients in thin films (DGT). Probabilistic risk assessment (PRA) was performed using Monte Carlo simulation. In addition, the species sensitivity distribution (SSD) was constructed using acute toxicity data to model the sensitivity of aquatic species towards metals. Three evaluation methods, namely, toxic units based on total content, modified potential ecological risk index (RI) based on chemical fractionation and DGT-SSD coupled PRA, were implemented and compared. Results showed that trace metals, especially Cd, were significantly affected by anthropogenic activities. Chemical fractionation analysis revealed that the majority of Cd was readily available to aquatic organisms, while Cr was stable under normal conditions. Toxic units based on the total content demonstrated that metals in sediment were at 91.6 % low and 8.4 % medium toxicity levels, while the modified RI based on chemical fractionation found toxicity levels of 84.1 % low and 15.9 % medium. Furthermore, the combined toxicity calculated from DGT-SSD coupled PRA showed that trace metals in sediment had a 24.8 % probability of toxic effects towards aquatic organisms, with Cu, Zn, Cd, and Ni being the main contributors. Comparative analysis suggested that the DGT-SSD coupled PRA could provide a more objective and scientific evidence for lake management with regard to metal contamination.

Accumulation of microplastics in fish guts and gills from a large natural lake: Selective or non-selective?

In recent years, microplastics (MPs) have become emerging contaminant causing widespread concern about their ecotoxicological effects. However, little is known regarding the accumulation of MPs in different tissues of fishes, especially for freshwater fishes in natural environments. In this study, MPs in guts and gills of 11 fish species from Lake Chao, China were examined to explore the accumulation differences and foraging preferences of MPs. In general, MPs in fish guts varied from 2.85 to 8.38 items/individual, while ranged from 3.06 to 8.90 items/individual in fish gills. In terms of characteristic composition (shape, color, size, and polymer type), our results demonstrate higher occurrence of fibrous, black, small sized (<1 mm), and polypropylene MPs. Meanwhile, MPs concentrations in fish guts differed significantly among various feeding groups, with none significant difference detected in fish gills. In addition, fish guts exhibit more distinct foraging preferences for specific featured MPs in contrast with fish gills. These results indicate selective MPs accumulation in fish guts whereas random MPs accumulation in fish gills. Fish gills, adhering MPs by non-selective water exchange, may be more related to the real-time MPs abundance in water. To some extent, fish gills may be employed as important instruments to reflect MPs contamination in aquatic environments. Influenced by diverse feeding behaviors such as visual cues and sensory systems, MPs accumulation in fish guts reflect intrinsic differences, thus making fish guts sensitive organ in monitoring MPs' ecological risk for their health.

Exciton-induced mid-infrared optical nonlinearity of wide bandgap hexagon boron nitride.

In this Letter, an exciton absorption assumption is made to explain the mid-infrared saturable absorption performance of the 2D h-BN nanosheet. The exciton binding energy of ∼0.4 eV corresponds to the light wavelength around 3 µm, matching well with the experimental results. Experimentally, the h-BN saturable absorber (SA) shows a modulation depth of 5.3% in the wavelength region of 3 µm. By employing the h-BN SA in an Er:Lu2O3 laser, laser pulses with a pulse duration of 252 ns are realized at a repetition rate of 169 kHz, corresponding to a pulse energy of 3.55 µJ and peak power of 14 W. The exciton absorption assumption will help obtain a better understanding of the nonlinear optical dynamics in 2D materials from a new perspective.

Source tracing with cadmium isotope and risk assessment of heavy metals in sediment of an urban river, China.

The Nanfei River was one of dominant inflowing rivers of the fifth largest freshwater Chaohu Lake in China, which had been subjected to increasing nutrients and contaminants from population expansion, rapid industrialization and agricultural intensification in recent decades. In present study, surface sediment from the Nanfei River was collected to investigate the anthropogenic impact on distribution and bioavailability of heavy metals. Possible Cd sources along the river were constrained by using Cd isotope signatures and labile concentrations of heavy metals in sediment were determined through the DGT technique for risk assessment. Results showed that Cd in river sediment showed greatest enrichment (EF 0.8-9.4), indicating massive pollution from anthropogenic activities. Among the various possible Cd source materials, urban road dust, industrial soil and chicken manure, displayed higher Cd abundance and enrichment that might contribute to Cd accumulation in river sediment. Cadmium isotopic composition in river sediment was ranged from -0.21 ± 0.01‰ to 0.13 ± 0.03‰, whereas yielded relative variation from -0.31 ± 0.02‰ to 0.23 ± 0.01‰ in source materials. Accordingly, Cd sources along the river were constrained, i.e. traffic and industrial activities in the upper and middle reaches whereas agricultural activities in the lower reaches. Furthermore, the evaluation on ecological risk of heavy metals in sediment on basis of SQGs and DGT-labile concentrations demonstrated that Pb and Zn might pose higher risk on aquatic species. The present study confirmed that Cd isotopes were promising source tracer in environmental studies.

Seasonal variation and ecological risk assessment of microplastics ingested by economic fishes in Lake Chaohu, China.

Microplastic (MP) contaminations in freshwater organisms have attracted substantial attention worldwide. However, seasonal field studies of MPs concentrations in aquatic life are scarce. In this study, we analyzed the seasonal variation and ecological risk of MPs concentrations in economic fish species from Lake Chaohu in China between wet and dry seasons. Within both seasons, MPs in fish were systematically analyzed using methods of KOH digestion, NaCl density floatation and raman spectroscopy. MPs abundance in economic fishes were significantly higher in dry season than that in wet season, which can be ascribed to the MPs' amplification effects in lacustrine ecosystems during dry season. Whereas, our results recorded similar and homogenized characteristic composition of MPs in economic fishes between wet and dry seasons. In both seasons, fiber was the main morphological type, black and blue were the most common MPs color, and MPs ranging from <0.5 mm accounting for the most abundant size. In addition, polypropylene (PP) and polyethylene terephthalate (PET) accounted for the most abundant polymer type detected by economic fishes in both seasons. In terms of feeding groups and habitat preferences, planktivorous and pelagic fish species exhibited sensitive variations of MPs concentrations between wet and dry seasons, thus being highlighted as good bioindicators of MPs contaminants in freshwater ecosystems. Our results revealed higher ecological risks of MPs in wet season than that in dry season when indicating from polymer risk index (H). By providing detailed and direct toxicity information, our study highlights the usage of polymer risk index for ecological risk assessment in aquatic organisms.

Investigation on the optical nonlinearity of the layered magnesium-mediated metal organic framework (Mg-MOF-74).

The wavelength-related optical nonlinearities of few-layer Mg-MOF-74 nanosheets were investigated in the wavelength region around 1.08, 1.94, and 2.85 µm by the closed aperture Z-scan, open aperture Z-scan and I-scan method. Under the excitation of 100-µJ laser pulses, the nonlinear refractive index (n2) of -7.7 ± 2.6, -131 ± 5 and 4.9 ± 0.2 cm2/W were obtained, respectively. The wavelength-related optical nonlinearity of the Mg-MOF-74 nanosheet was also investigated. In 2.85 µm wavelength region, the Mg-MOF-74 nanosheets shows a stable saturable absorption property with a modulation depth of 8% and a saturation intensity of 170 mJ/cm2. In the 1.08 and 1.94 µm wavelength regions, we can observe that the Mg-MOF-74 transits from saturable absorption regime to reverse saturable absorption regime with the increasing incident laser intensity. Employed as a saturable absorber in a Er:Lu2O3 laser, Mg-MOF-74 nanosheet shows a thickness-related laser modulation performance. The shortest laser pulse of 284-ns was achieved under a repetition rate of 116 kHz with a 6-nm-thick Mg-MOF-74 nanosheet, which corresponds to a pulse energy of 3.2 µJ and a peak power of 11.4 W.

Numerical modeling of ultrasonic cavitation by dividing coated microbubbles into groups.

Homogeneous cavitation models usually use an average radius to predict the dynamics of all bubbles. However, bubbles with different sizes may have quite different dynamic characteristics. In this study, the bubbles are divided into several groups by size, and the volume-weighted average radius is used to separately calculate the dynamics of each group using a modified bubble dynamics equation. In the validation part, the oscillations of bubbles with two sizes are simulated by dividing them into 2 groups. Comparing with the predictions by the Volume of Fluid (VOF) method, the bubble dynamics of each size are precisely predicted by the proposed model. Then coated microbubbles with numerous sizes are divided into several groups in equal quantity, and the influence of the group number is analyzed. For bubble oscillations at f = 0.1 MHz and 1 MHz without ruptures, the oscillation amplitude is obviously under-estimated by the 1-group model, while they are close to each other after the group number increases to 9. For bubble ruptures triggered by Gaussian pulses, the predictions are close to each other when more than 5 groups are used.

Microplastic contamination assessment in water and economic fishes in different trophic guilds from an urban water supply reservoir after flooding.

Rain and floods events are responsible for the transport of microplastics in freshwater ecosystems, yet to date, rare study has examined microplastics pollution in urban water supply reservoirs during such events. In this study, we investigated the concentrations and characteristics of microplastic in water and economic fish species with different feeding guilds in the Dafangying Reservoir, an important source of drinking water for Hefei city. Microplastic concentrations in water were relatively higher than that in natural lakes, indicating abundant microplastic contaminants input through overland runoff triggered by flooding. Our results detected five types (fiber, debris, film, microbead and particle) and six colors (black, transparent, blue, yellow, red and green) of microplastics in water samples. Fiber accounted for the dominant shape, which may result from the household sewage from washing clothes and desquamated fiber transported by wind and overland runoff. Meanwhile, transparent was the predominant microplastic color, which can be ascribe to the widely use of intentionally manufactured transparent disposable plastic commodities in cities. Then in fish samples, the microplastic concentrations ranged from 8.75 to 51.3 items/individual in fish guts, and 9.5-52.6 items/individual in fish gills. Our results demonstrated significant higher microplastic concentrations in planktivorous and herbivorous species. The filter feeding capture mode, i.e., engulfing floating prey through frequently drawing in large volume of water confused with microplastics, may result in the higher microplastic concentrations of planktivorous fishes. Due to the dense microplastics adhering on plant surface, herbivorous fishes can concentrate higher microplastics abundance through the ingestion of macrophytes. According to the biological concentration factor (BCF), all the determined microplastics gave BCF far below 1, suggesting the low bioaccumulation capacity of microplastics in fish species.

Uncovering residents and restaurants' attitude and willingness toward effective food waste management: A case study of Macau.

Food waste has attracted wide attention around the world. A better understanding of food waste generation and consumers' willingness to pay (WTP) for effective food waste management is important for addressing growing food waste challenges, but this is still largely missing in the literature, especially for developing countries and cities in Asia. In this study, we conducted field interviews and questionnaire surveys, with effective samples of 463 residents and 18 restaurants in Macau. Our results show that over 80% of respondents think food waste in Macau is serious. "Food exceeded expiration date (28.2%)" and "Ordering too much food (39.5%)" are the two main reasons for throwing away food at home and when eating out, respectively. Vegetables and fruits (22.4%) are the most common type of food wasted at home, followed by snacks (17.3%), in Macau. About 70% of respondents agreed to pay for separate food waste collection and treatment facilities, and the WTP value per household in Macau is 42.5 MOP (Macau Pataca)/month. Respondents' income level was positively and significantly correlated with their WTP, while age and educational level had negative effects on the WTP, under the 5% significance level. Some respondents' perceptions and attitudes on food waste also significantly affected their WTP, according to our analysis. Because of the lack of effective management measures and collection facilities, about 72% of surveyed restaurants mixed their food waste into municipal solid waste (MSW). More information sharing, education and promotion should be done to raise environmental protection awareness and improve the food waste treatment system.

Optical nonlinearity and laser modulation performance of FeNi-LDH in the mid-infrared region.

In this Letter, we prepare FeNi-layered-double-hydroxide (LDH) nanoflakes and illustrate the corresponding microcosmic morphology. The optical response and laser modulation performance of the nanoflakes in the mid-infrared region were investigated for the first time, to the best of our knowledge. Employed as a saturable absorber in an ${\rm Er}{:}{\rm Lu}_2{\rm O}_3$ laser system, pulses with 256-ns duration were yielded at a repetition of 129 kHz under 7.8-W pump power, which corresponds to a pulse energy of 4.98 µJ.

Repercussions of COVID-19 pandemic on solid waste generation and management strategies.

It has been over ten months since the beginning of the 2019 coronavirus disease (COVID-2019), and its impact on solid waste management, especially medical waste, is becoming clearer. This study systematically reviews the potential influences of the COVID-19 pandemic on medical waste, personal protection equipment waste and municipal solid waste (MSW), and discusses the corresponding measures and policies of solid waste management in typical countries. The results show that the generation of medical waste from the pandemic increased significantly, with 18%-425% growth. It is estimated that the daily output of COVID-19 medical waste increased from 200 t/d on Feb. 22 to over 29000 t/d at the end of September 2020 throughout the world. The use of personal protective equipment will continue to grow in the long-term, while the blockade and isolation measures greatly reduced the volume of commercial waste, especially for tourist cities, and part of this waste was transferred to household waste. Residents' attitudes and behavior toward food waste have changed due to the COVID-19 pandemic. In response to the pandemic, international organizations and several countries have issued new policies and guidelines and adjusted their management strategies for medical waste and MSW treatment. The pandemic has brought specific challenges to the disposal capacity of medical waste worldwide. It has also brought about the stagnation of policies related to the reduction of plastic products and waste recycling. This study will provide some useful information for managers and governmental officials on effective solid waste management during and after the COVID-19 pandemic.