11/11/2024


The diagnostic ratios and the results of principal component analysis (PCA) and multiple linear regression of the absolute principal component scores (MLR-APCS) indicated that the PAHs were mainly contributed from sources related to petrogenic (71.4%) and vehicles (28.6%). Most likely due to MPs on the sea surface coming into contact with floating oil spills from ships or floating tar particles. Microplastics are plastic particles which are widely distributed in the environment. The pollution of microplastics in environment have attracted increasing attention in recent years. This paper reviews research progress in sources, analytical methods, eco-environmental effects and control in environment, and suggests relevant countermeasures in governance and research. Microplastics mainly originate from two sources firstly, a significant direct input of primary microplastics; second, secondary microplastics generate from the fragmentations of larger plastic materials. The analysis and identification of microplastics are critical to other researches, and related instrument methods have also been applied to the analysis and identification of microplastics. The advantages and disadvantages of microplastics analytical methods were reviewed. The eco-environmental effects of microplastics can be divided into four aspects adsorption, biological uptake, ecotoxicological and combined pollution. Control measures need to strengthen the systematic research of microplastics pollution control and management technology system from the aspects of organizational cooperation, technological research and development, laws and regulations. In the future, a unified quantitative analysis method for microplastics should be established, and more accurate traceability analysis techniques should be developed to further explore its environmental behavior and fate. To strengthen scientific research on microplastic pollution in terrestrial, freshwater and atmospheric environments, and develop more scientific and rational control policies. This paper aims to provide a theoretical basis for the prevention and control of microplastics pollution, and also provides insights for the next step of research. The use of a variety of antibiotics in fish farming raises serious concern about the development of antibiotic resistance. Sulfonamides antibiotics (SAs), which are widely used in aquaculture and generate large eco‒toxicological effects with significant mutagenicity and teratogenic consequences, are still difficult to determine in aquatic organisms. In this study, an automatic technology was developed by coupling on‒line solid phase extraction system (on‒line SPE) with ultra‒high‒performance liquid chromatography spectrometry‒mass spectrometry (UHPLC‒MS/MS). Particularly, using a single on‒line column in the process of sample pretreatment, e.g., HLB or C18, phospholipids that potentially caused the matrix effect cannot be removed form biological sample. We applied a mixed cation exchange column (Oasis® MCX) connected with a hydrophilic lipophilic balance column (Oasis® HLB) in series in on‒line SPE clean‒up to remove interferences and finally obtained a clear and stable eluant. The on‒line SPE working conditions and UHPLC‒MS/MS parameters were optimized for their sensitivity, accuracy, decision limit, and detection capability, which were further calibrated for fish, shrimp and crab. The results showed that the limits of detection and limits of quantification ranged from 1.46 to 15.5 ng/kg, and 4.90-51.6 ng/kg, respectively. Accuracy values covered 71.5%-102% at the three concentration levels (0.1, 0.5, 1.0 μg/kg) for all compounds and average repeatability (relative standard deviation, RSD%) ranged from 3.47% to 14.2%. This on‒line SPE coupled with UHPLC‒MS/MS method is a way forward for an automatic, powerful detection technology for determination of antibiotics from complex matrix. Excitation-emission matrix (EEM) fluorescence spectroscopy is a powerful tool for the characterization of dissolved organic matter (DOM) in wastewater systems. It is of particular value if its utility could be extended by connecting the spectral features to hydrophobicity, one of the fundamental physicochemical properties of DOM. In this study, we employed a DAX-8 resin column to fractionate the hydrophobic/philic components of DOM and determine the relative degree of hydrophobicity by adjusting the critical retention factor (k'cr, the ratio of treated water sample volume to column volume). A higher k'cr would result in a higher hydrophobicity of the column effluent. At different k'cr values (5, 10, 25, 50, 100, and 200), the EEM characteristics of the obtained DOM components were inspected, including overall properties (average fluorescence per total organic carbon and UV absorbance), regional properties (fluorescence regional integration (FRI) and its secondary parameters), and energy-related properties (energy level of the excited states, Stokes shift for relaxation of the excited states, and fluorescence lifetime). In case studies of a wastewater membrane bioreactor and an oxidation ditch, plenty of the EEM properties varied significantly with logk'cr (r > 0.9, p  less then  0.05). The average fluorescence per UV absorbance (reflecting quantum yield), fluorescence proportion at Stokes shift ≥ 1.1 μm-1, and some secondary FRI parameters presented the best linear fitting with logk'cr, suggesting a smooth variation of the π-conjugated structures with the relative degree of DOM hydrophobicity. https://www.selleckchem.com/products/ademetionine.html This may help to further understand the relationship between EEM fingerprints and DOM hydrophobicity. Mannose-binding lectin (MBL) deficiency is a common innate immune system deficiency, and is associated with exacerbations and increased colonization of some pathogens. However, the response of the gut microbiota, a pivotal factor in host health, to MBL deficiency is not clear. In this study, MBL-/- and wild-type (WT) mice were generated by backcrossing from MBL-A and MBL-C knockout (KO) mice, and fecal samples were collected at different ages (4th, 8th, 12th, 19th and 27th weeks). The gut microbiota was analyzed by high-throughput sequencing with universal 16S rDNA primers (V3-V5 region). The results showed that structural segregation of the gut microbiota occurred at the 8th, 12th, 19th and 27th weeks of age, although there were no significant differences in alpha diversities between MBL-/- and WT mice at different ages. Impressively, in MBL-/- mice, Akkermansia (from the family Verrucomicrobiaceae) were decreased significantly, Lactobacillus (from the family Lactobacillaceae) abundances, Alistipes and Rikenella (both from the family of Rikenellaceae) were always enriched.