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Atmospheric fine particle pollution has an important impact on regional environment, global climate and human health, so it has been one of the key and difficult points of air pollution prevention and control. In recent years, due to the continuous promotion of China's air pollution prevention and control plan, the problem of atmospheric fine particle pollution has been significantly improved, and the relevant measurement technology has also made considerable progress. In this paper, the development and application of atmospheric fine particle measurement technology in recent years are reviewed based on the information of physical and chemical parameters such as atmospheric fine particle number concentration, particle size distribution and chemical composition. For the measurement of fine particle number concentration, it mainly includes diffusion charge counting and condensation particle counting. The former is mainly applicable to the combustion emission scenario, and the latter is applicable to the urban air low concentration scenario. For the measurement of fine particle size, it mainly involves single particle size and overall particle size spectrum analysis. The single particle size is mostly determined by electron microscopy and optical microscopy, and the particle size spectrum analysis is mainly determined by electro migration classification. For the component measurement of fine particles, aerosol mass spectrometry and spectral analysis are mainly used. Finally, in view of the new requirements of research on the evolution mechanism of atmospheric particulates and intelligent monitoring and supervision, this paper discusses the future development of atmospheric fine particulates in multi-parameter comprehensive characterization, rapid measurement of dynamic processes, high-performance micro-nano sensors and other directions.

Background: Ammonia, a ubiquitous contaminant in aquatic ecosystems, poses multifaceted threats to fish species at elevated concentrations. Methods: In order to investigate the toxic effects of chronic ammonia stress on the liver of juvenile Micropterus salmoides, the present experiment was conducted to investigate the differences in changes in liver tissue structure, enzyme activities, and metabolomes after 28 days of ammonia exposure (0, 4, 8, and 16 mg/L). Results: The findings revealed that ammonia exposure induced significant oxidative stress in the liver, manifesting in decreased activities of antioxidant enzymes SOD and GSH-Px, elevated levels of GSH, GST, and MDA, and heightened activities of immune enzymes LZM, ALP, and ACP. An increase in ammonia concentration exacerbated liver tissue damage. Metabolome analysis further unveiled perturbations in liver metabolites of Micropterus salmoides exposed to ammonia, with Ala-His emerging as a potentially pivotal functional substance under chronic stress. Specifically, the 4 mg/L group responded to ammonia toxicity by augmenting GSH and L-Carnosine levels, the 8 mg/L group detoxified via upregulation of L-Glutamine, and the 16 mg/L group mitigated toxicity through the urea synthesis pathway. Conclusions: This research offers preliminary insights into the toxicological responses of Micropterus salmoides under chronic ammonia stress. It is suggested that the duration of ammonia concentration exceeding 4 mg/L in high-density aquaculture should not exceed 7 days. [ABSTRACT FROM AUTHOR]

Rapid road network expansion has heightened the importance of surface condition information for traffic accident prevention and route optimization. This article introduces a laser diode-based sensor that identifies seven surface conditions and accurately measure ice, water, and snow film thicknesses on roads. An optical module was developed to detect weak optical signals based on the characteristic absorption spectrum of the target surface. The module used three laser diodes (1310, 1440, and 1550 nm wavelengths) as light sources. Additionally, a road classification algorithm that is adaptable to foggy weather was developed using a multi-wavelength processing protocol. The sensor was subjected to numerous calibration and performance verification experiments. During thick foggy measurements, the processed spectra displayed a maximum variation of 2.372% across a 600 to 25,000 m visibility range with a relative standard deviation of only 0.328%. This demonstrated effective weakening of the effects of visibility variations. During winter field testing, the sensor classified road conditions effectively and accurately measured ice, snow, and water film thicknesses, with a correlation coefficient of 0.97444. The accuracy of the measurements was less than 0.5 mm. The sensor's effectiveness for long-term field-based road testing has been verified. [ABSTRACT FROM AUTHOR]

Stocking density is a key factor affecting the health of aquatic organisms in industrial aquaponics. In this study, Micropterus salmoides were assigned to one of two density groups (160 and 120 fish/m3) for 40 days. The growth performance, intestinal morphology, enzyme activity, and microbial communities were compared between the two density groups. The findings revealed that the higher stocking density condition exhibited an increased weight gain rate and specific growth rate during the developmental phase of the juvenile M. salmoides. Moreover, remarkable increases in villi height, villi width, and muscular layer thickness were observed. Additionally, this elevated stocking density condition also enhanced the activity of intestinal antioxidant enzymes, consequently improving the structural integrity of the intestine and augmenting the digestive and absorptive capacities of the juvenile M. salmoides. With regard to the intestinal microbial community, the dominant phyla detected were Firmicutes and Proteobacteria. However, under the higher stocking density condition, there was a significant upsurge in the abundance of Mycoplasma. Consequently, it is advised to mitigate the abundance of such pathogenic microorganisms through the regulation of the water environment during the aquacultural process. Drawing from recent investigations on the impact of various factors on the intestinal microbiota of M. salmoides, it can be deduced that the composition of the intestinal microbiota is closely intertwined with factors including aquaculture practices, feed composition, water environment, and developmental stage. In summary, the aforementioned research findings possess noteworthy implications for the control of stocking density in the cultivation of juvenile M. salmoides. [ABSTRACT FROM AUTHOR]