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A chitosan containing thiophene group and its preparation method and application
No full text本发明涉及海洋化工工程领域，具体涉及一种含噻吩基团的壳聚糖及其制备方法和应用。含噻吩基团的壳聚糖结构如式一所示；其制备方法简单，原料来源广泛，无副作用。实验证明，所得的含噻吩基团的壳聚糖衍生物具有良好的抗氧化活性及抑菌活性，可广泛应用于农业、医药和食品等领域。式一
Crawler grass chopper
No full text本实用新型公开了履带碎草机，涉及碎草机技术领域，该设备包括履带机，所述履带机的一端设有力挖铲，固定机构的内部设有将互花米草打碎的碎草机构。本实用新型通过设置力挖铲和浮筒，可以使履带机在易陷滩涂中行驶时，操作力挖铲将其插入泥中，力挖铲往后发力，可辅助履带机向前移动，同时，履带机两侧装有浮筒，使履带机不会在易陷滩涂中陷车，进一步提高履带机在泥滩中的通行能力，达到了履带机在易陷滩涂中的通行能力更好的效果，从而解决现有互花米草治理设备容易陷车的难题，本实用新型中设置碎草机构, 启动驱动电机带动连接杆进行转动时使圆盘刀进行转动，通过定刀与转动的圆盘刀相配合，从而打碎防护罩下的互花米草，对其进行碎草治理
Variations of the atmospheric polycyclic aromatic hydrocarbon concentrations, sources, and health risk and the direct medical costs of lung cancer around the Bohai Sea against a background of pollution prevention and control in China
No full textThe Bohai Sea (BS) region, an area of China that is severely polluted with atmospheric polycyclic aromatic hydrocarbons (PAHs), has received wide attention in recent decades. To characterize the variations of the concentrations and sources of PAHs from June 2014 to May 2019, 15 PAH congeners (Sigma(15)PAHs) were measured in atmospheric samples (N=228) collected at 12 sites around the BS, and the health risk and direct medical costs associated with lung cancer caused by exposure to PAHs were also estimated. The annual daily average concentration of Sigma(15)PAHs was 56.78 +/- 4.75ng m(-3), which was dominated by low molecular weight PAHs (LMW-PAHs) containing three rings (58.7 +/- 7.8%). During the 5-year sampling period, the atmospheric Sigma(15)PAHs concentration reduced by 17.5% for the whole BS region, with an especially large drop of 51.7% observed in the tightly controlled area of Tianjin (TJ), which was mainly due to a decrease in the concentration of high molecular weight PAHs (HMW-PAHs) containing five or six rings. Generally, the concentration of Sigma(15)PAHs was highest in winter and lowest in summer, which can mainly be attributed to the change in LMW-PAH concentration. Based on the positive matrix factorization (PMF) model, PAHs in the BS region were mainly ascribed to coal combustion and biomass burning. The PAH contributions of coal combustion and motor vehicles showed different trends for the BS region (PAHs from coal combustion rose by 7.2% and PAHs from motor vehicles fell by 22.4%) and for TJ (PAHs from coal combustion fell by 12.6% and PAHs from motor vehicles rose by 6.9%). The incidence of lung cancer (ILCR) caused by exposure to atmospheric PAHs decreased by 74.1% and 91.6% from 2014 to 2018 in the BS region and in TJ, respectively. This was mainly due to the decrease in the concentration of highly toxic HMW-PAHs and was reflected in USD10.7 million of savings in direct medical costs of lung cancer caused by exposure to PAHs, which represent a decrease of 46.1% compared to the corresponding costs before air pollution prevention and control was implemented around the BS. There was an even higher reduction in medical costs of 54.5% in TJ. Hence, this study proves that implementing pollution prevention and control not only effectively reduced the concentration of pollutants and the risks caused by them, but it also significantly reduced the medical costs of diseases caused by the corresponding exposure
Artificial wetlands providing space gain for the suitable habitat of coastal Pied Avocet
No full textA large number of artificial wetlands have replaced natural wetlands along waterbird migration routes to supply breeding, resting and feeding grounds for waterbirds. Effective identification of potential artificial wetlands that could serve as suitable habitats for waterbirds can provide important reference for field investigation and waterbird conservation. In this study, the habitat suitability of the Pied Avocet in the Yellow River Delta (YRD), China was simulated with the optimized MaxEnt model based on its occurrence records and environmental variables. The results showed that the MaxEnt model could well predict the habitat suitability of the Pied Avocet (Recurvirostra avosetta) in the YRD. The suitable habitats were distributed in the specific areas of the coastal zone, and artificial wetlands such as salt pans and mariculture ponds were the main components in the high-suitability area. The top three environmental factors affecting habitat selection were the land use and land cover (LULC), distance to the coastline and normalized difference vegetation index (NDVI). This paper emphasizes the role of artificial wetlands in providing suitable habitat for waterbirds. In order to better protect the habitat of waterbirds and alleviate human-bird conflict in the YRD, some targeted suggestions were put forward for the management gap of artificial wetlands. This study has strong practical significance for the protection and habitat management of waterbirds in the YRD. The methodology we employed is transferable to other wetlands, where efficient management is inhibited due to a lack of comprehensive field investigations
Multifractal parameters reveal the impacts of shrub encroachment on soil particle size distribution (PSD) in a coastal wetland of the Yellow River Delta
No full textShrub encroachment in coastal wetlands leads to heterogeneous distribution of soil resources, which may affect soil particle size distribution (PSD). Fractal theory was widely used to quantify the characteristics of soil PSD. However, exploration on the spatial changes in PSD of deep soil layers due to shrub-encroached vegetation succession is limited. Multifractal theory and GIS spatial analysis tools were used to spatially quantify the changes in soil PSD at different soil layers (0-80 cm) in a coastal wetland landscape (100 x 120 m) encroached by a native shrub Tamarix chinensis in the Yellow River Delta (YRD), China. We also discussed the potential mechanisms of soil PSD changes contributed by shrub encroachment. The results showed that higher content of fine sand, medium sand and coarse sand, while lower content of silt and very fine sand in 0-10 cm were observed in T.chinensis patches than in single T. chinensis and bare land (p single shrub > bare land in each layer. In addition, the D0 suggested that influences of T.chinensis on soil PSD can remain 70 cm below the surface in our case. Considering the complex sedimentary process in the YRD, the processes of water and wind erosion mediated by shrub encroachment, the positive feedback based on plant preferences and the mixed effects of shrub and grass species might promote the redistribution of soil particle size. Encroachment in coastal wetland of the YRD caused changes in soil PSD, especially at the surface soil layer. Multifractal parameters could quantify subtle characteristics of soil PSD in shrub-encroached area. Our work indicates that shrub encroachment in coastal wetland plays a significant role in altering regional and even global soil environments
Spatial effects of shrub encroachment on wetland soil pH and salinity in the Yellow River Delta, China
No full textThe encroachment of woody shrubs in grass-dominated coastal salt marsh ecosystems has potentially influenced soil physical and chemical processes at various scales. Understanding the effects of shrub encroachment on those ecosystems requires assessments of the spatial heterogeneity in soil variables across multiple scales. Combined with GIS spatial tools and sampling data, we evaluated the vertical (0-80 cm) and spatial characteristics of soil pH and soil salinity (or electrical conductivity, EC) in a coastal wetland that experienced 40 years of shrub (specifically, the Tamarix chinensis species) encroachment. In order to obtain the information of the spatial patterns and scale domains of soil pH and EC, we employed the lacunarity analysis method. Furthermore, we utilized both Mantel test and Pearson correlation to identify their relationship. The results revealed that shrub encroachment had notable impacts on the magnitude and spatial patterns of soil pH and EC. These effects were driven by specific encroaching processes. Specifically, large shrub patches (SP) resulted in a significant rise in soil pH and a noteworthy reduction in soil EC. In addition, small shrub clusters (SC) caused a notable reduction in soil EC, but did not have significant impacts on soil pH. The impacts of shrubs on soil pH were primarily observed in 0-20 cm, whereas their effects on soil EC extended to deeper soil layers (e.g., up to 60 cm). Shrub encroachment also increased the landscape heterogeneity of both soil pH and EC, with the effects being more pronounced on soil EC. The lacunarity analysis revealed that the spatial heterogeneity of soil EC differed significantly among four depths, 0-20, 20-30, 30-60, and 60-80 cm, while the heterogeneity of soil pH varied significantly between two depths of 0-60 and 60-80 cm. Furthermore, soil pH and soil EC showed a strong spatial association, with a negative relationship observed between the two variables within each soil layer. Our study at the landscape scale highlights the opposite responses of soil pH and EC in saline-alkali wetlands to shrub encroachment. By understanding the impacts of shrubs on soil properties, we can enhance our ability to effectively restore and manage these degraded ecosystems
The water-insoluble organic carbon in PM<sub>2.5</sub> of typical Chinese urban areas: light-absorbing properties, potential sources, radiative forcing effects, and a possible light-absorbing continuum
No full textWater-insoluble organic carbon (WIOC) constitutes a substantial portion of organic carbon (OC) and contributes significantly to light absorption by brown carbon (BrC), playing pivotal roles in climate forcing. China is a hotspot region with high levels of OC and BrC, but information regarding the sources and light-absorbing properties of WIOC on a national scale remains scarce. Here, we investigated the light-absorbing properties and sources of WIOC in 10 representative urban cities in China. On average, WIOC made up 33.4 +/- 7.66 % and 40.5 +/- 9.73 % of concentrations and light absorption at 365 nm (Abs(365)) of extractable OC (EX-OC), which includes relatively hydrophobic OC (WIOC and humic-like substances, HULIS-C) and hydrophilic OC (non-humic-like substances, non-HULIS-C). The mass absorption efficiency of WIOC at 365 nm (MAE(365)) was (1.59 +/- 0.55 m(2) (g C)(-1)) comparable to that of HULIS (1.54 +/- 0.57 m(2) (g C)(-1)) but significantly higher than non-HULIS (0.71 +/- 0.28 m(2) (g C)(-1)), indicating that hydrophobic OC possesses a stronger light-absorbing capacity than hydrophilic OC. Biomass burning (31.0 %) and coal combustion (31.1 %) were the dominant sources of WIOC, with coal combustion sources exhibiting the strongest light-absorbing capacity. Moreover, employing the simple forcing efficiency (SFE300-700 nm) method, we observed that WIOC exhibited the highest SFE300-700 nm (6.57 +/- 5.37 W g(-1)) among the EX-OC fractions. The radiative forcing of EX-OC was predominantly contributed by hydrophobic OC (WIOC - 39.4 +/- 15.5 % and HULIS - 39.5 +/- 12.1 %). Considering the aromaticity, sources, and atmospheric processes of different carbonaceous components, we propose a light-absorbing carbonaceous continuum, revealing that components enriched with fossil sources tend to possess stronger light-absorbing capacity, higher aromatic levels, increased molecular weights, and greater recalcitrance in the atmosphere. Reducing fossil fuel emissions emerges as an effective means of mitigating both gaseous (CO2) and particulate light-absorbing carbonaceous warming components
Key drivers of hypoxia revealed by time-series data in the coastal waters of Muping, China
No full textCoastal hypoxia (low dissolved oxygen in seawater) is a cumulative result of many physical and biochemical processes. However, it is often difficult to determine the key drivers of hypoxia due to the lack of frequent observational oceanographic and meteorological data. In this study, high-frequency time-series observational data of dissolved oxygen (DO) and related parameters in the coastal waters of Muping, China, were used to analyze the temporal pattern of hypoxia and its key drivers. Two complete cycles with the formation and destruction of hypoxia were captured over the observational period. Persistent thermal stratification, high winds and phytoplankton blooms are identified as key drivers of hypoxia in this region. Hypoxia largely occurs due to persistent thermal stratification in summer, and hypoxia can be noticeably relieved when strong wind mixing weakens thermal stratification. Furthermore, we found that northerly high winds are more efficient at eroding stratification than southerly winds and thus have a greater ability to relieve hypoxia. This study revealed an episodic hypoxic event driven by a phytoplankton bloom that was probably triggered by terrestrial nutrient loading, confirming the causal relationship between phytoplankton blooms and hypoxia. In addition, we found that the lag time between nutrient loading, phytoplankton blooms and hypoxia can be as short as one week. This study could help better understand the development of hypoxia and forecast phytoplankton and hypoxia, which are beneficial for aquaculture in this region
Genome-Wide Identification and Comparative Analysis of Elongation of Very Long-Chain Fatty Acid (Elovl) Genes in Echinoderms
No full textElongation of very long-chain fatty acid (Elovl) proteins is the critical rate-limiting enzyme that catalyzes the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs). Echinoderms are extremely important research objects in various fields, such as regeneration studies and developmental biology. However, to date, the genome-wide characterization and analysis of Elovl genes in echinoderms have not been investigated. In this study, the identification and analysis of Elovl genes in 10 representative echinoderms were performed using bioinformatics methods. A total of 117 Elovl genes have been found in the studied echinoderms. The phylogenetic tree showed that all Elovl genes from echinoderms can be subdivided into 6 classes, Elovl3-like class, Elovl4-like class, Elovl5-like class, Elovl6-like class, Elovl7-like class, and Elovl8-like class. Furthermore, the selection pressure analysis suggested that Elovl genes in echinoderms were mainly constrained by strong purifying selection events. In general, this study provides a molecular basis for echinoderm Elovl genes and may serve as a reference for in-depth phylogenomics
Heterogeneous degradation of chloramphenicol antibiotic by peroxymonosulfate activated by FeS and FeS<sub>2</sub>: Mechanism and effects of catalysts dosage and pH
No full textAntibiotics in the environmental waters pose long-term threat to ecological safety because of their persistent and potential toxic nature. FeS and FeS2 were proved to be efficient catalysts for the activation of peroxymonosulfate (PMS) and the generation of sulfate radical generation for refractory pollutant degradation. However, their performance for antibiotic degradation has not yet been comparatively and comprehensively investigated. Herein, the FeS/PMS and FeS2/PMS systems were developed to explore chloramphenicol (CAP) degradation under equal conditions. The results show that CAP was efficiently degraded in both two systems, with a removal efficiency exceeding 90 % within 120 min using 6 mM PMS and 0.6 g/L catalysts. Acceleration in degradation rate was observed in the FeS2/PMS system when the catalyst dosage ranged from 0.1 g/L to 1.0 g/L (constant PMS concentration) with a reaction rate constant (k(obs)) of 2.1-fold higher than that in the FeS/PMS system. However, the k(obs) were comparable with the PMS concentration range (constant catalyst dosage) in the two systems, suggesting that the catalysts were the rate-limiting step in CAP degradation process. The initial pH strongly affected CAP degradation in the FeS/PMS system but had little effect on that in the FeS2/PMS system. Surface Fe2+ played a dominant role in PMS activation, and S-2(2-)/S2- facilitated Fe2+ regeneration. Further, both FeS and FeS2 had stable activity for PMS activation during long-term use. This study proves the effectiveness of FeS and FeS2 for PMS activation for antibiotic degradation and differentiates their catalytic qualities, which will provide alternative heterogeneous catalysts for practical application