Polymer-based cascaded waveguide Bragg grating for blood glucose sensing.

Waveguide Bragg grating (WBG) blood glucose sensing, as a biological sensing technology with broad application prospects, plays an important role in the fields of health management and medical treatment. In this work, a polymer-based cascaded WBG is applied to glucose detection. We investigated photonic devices with two different grating structures cascaded-a crossed grating and a bilateral grating-and analyzed the effects of the crossed grating period, bilateral grating period, and number of grating periods on the sensing performance of the glucose sensor. Finally, the spectral reflectance characteristics, response time, and sensing specificity of the cascaded WBG were evaluated. The experimental results showed that the glucose sensor has a sensitivity of 175 nm/RIU in a glucose concentration range of 0-2 mg/ml and has the advantages of high integration, a narrow bandwidth, and low cost.

Effect of pyrolysis temperature and molecular weight on characterization of biochar derived dissolved organic matter from invasive plant and binding behavior with the selected pharmaceuticals.

A comprehensive understanding of the characteristics of biochar released-dissolved organic matter (BDOM) derived from an invasive plant and its impact on the binding behavior of pharmaceuticals is essential for the application of biochar, yet has received less attention. In this study, the binding behavior of BDOM pyrolyzed at 300-700 °C with sulfathiazole, acetaminophen, chloramphenicol (CAP), and carbamazepine (CMZ) was investigated based on a multi-analytical approach. Generally, the pyrolysis temperature exhibited a more significant impact on the spectral properties of BDOM and pharmaceutical binding behavior than those of the molecular weight. With increased pyrolysis temperature, the dissolved organic carbon decreased while the proportion of the protein-like substance increased. The highest binding capacity towards the drugs was observed for the BDOM pyrolyzed at 500 °C with the molecular weight larger than 0.3 kDa. Moreover, the protein-like substance exhibited higher susceptive and released preferentially during the dialysis process and also showed more sensitivity and bound precedingly with the pharmaceuticals. The active binding points were the aliphatic C-OH, amide II N-H, carboxyl CO, and phenolic-OH on the tryptophan-like substance. Furthermore, the binding affinity of the BDOM pyrolyzed at 500 °C was relatively high with the stability constant (logKM) of 4.51 ± 0.52.

The Emerging Role of Deubiquitinases in Radiosensitivity.

Radiation therapy is a primary treatment for cancer, but radioresistance remains a significant challenge in improving efficacy and reducing toxicity. Accumulating evidence suggests that deubiquitinases (DUBs) play a crucial role in regulating cell sensitivity to ionizing radiation. Traditional small-molecule DUB inhibitors have demonstrated radiosensitization effects, and novel deubiquitinase-targeting chimeras (DUBTACs) provide a promising strategy for radiosensitizer development by harnessing the ubiquitin-proteasome system. This review highlights the mechanisms by which DUBs regulate radiosensitivity, including DNA damage repair, the cell cycle, cell death, and hypoxia. Progress on DUB inhibitors and DUBTACs is summarized, and their potential radiosensitization effects are discussed. Developing drugs targeting DUBs appears to be a promising alternative approach to overcoming radioresistance, warranting further research into their mechanisms.

An 18.3 MJ charging and discharging pulsed power supply system for the space plasma environment research facility (SPERF): the subsystem for the magnetic mirror coil.

The magnetic reconnection process relevant to that at the magnetotail is one of the research contents of the Space Plasma Environment Research Facility, which is under construction at the Harbin Institute of Technology in China. Two magnetic mirror sub-coils placed symmetrically in the vertical direction and connected in series cooperate with a dipole coil to generate a magnetic field environment similar to the Earth's magnetotail. A capacitor-based pulsed power supply (PPS) system with a modular design is developed to excite two magnetic mirror sub-coils to generate a magnetic field with a magnetic flux density of not less than 200 G at the center of the two sub-coils. The PPS should deliver a pulsed current with a peak of more than 8 kA, and the duration of the current not be less than 95% of the peak over 5 ms to two magnetic mirror sub-coils when the charging voltage is not less than 20 kV. In addition, the duration from the peak to 10% of the peak is not more than 130 ms. The detailed design of the PPS is discussed in this paper, and a test method is designed to reduce the risk of damage to the wires and the connection between the wires and the coaxial cables of the PPS when the PPS discharges at a higher charging voltage. Finally, the discharge test of the PPS is carried out to verify the design of the PPS.

[Influence of Land Use Structure and Spatial Pattern on Water Quality of Small and Medium-sized Rivers in Poyang Lake Basin].

To reveal the influence mechanism of land use structure and spatial pattern on water quality of small and medium-sized rivers, water samples were collected from 25 sampling points in three small and medium-sized rivers of the Poyang Lake Basin in January 2022 and July 2022. Bioenv analysis, the Mantel test, and variance partitioning analysis were used to quantify the effects of land use structure and spatial patterns on water quality at different spatial scales; generalized additive models were used to fit the relationship between water quality and different land use structures and spatial patterns; and a generalized linear model was used to construct segmented regression models and calculate the thresholds based on the stepwise recursive method. The results showed that:① the average interpretation rate of land use structure and spatial pattern on river water quality was 59.72% during the wet period and 48.95% during the dry period. The sub-basin and riparian 100 m scales were the key scales of land use structure and spatial pattern affecting water quality in small and medium-sized rivers, with an average explanation rate of 54.70% and 64.88%, respectively. The joint explanation of land use structure and spatial pattern was an important factor driving the change in river water quality, accounting for 66.90% of the total explanation. ② The impact of land use structure on the water quality of small and medium-sized rivers had a significant threshold effect. When the proportion of construction land was less than 2%, farmland was less than 8%, or forest land was more than 82% at the sub-basin scale and the proportion of construction land was less than 12%, farmland was less than 41%, or forest land was more than 49% at the riparian buffer scale, all could significantly improve water quality. ③ The effect of spatial pattern on water quality in small and medium-sized rivers also had a threshold effect but was weaker than that of land use structure. A patch shape value more than 28.77 or patch diversity more than 0.69 at the sub-basin scale and a patch shape value more than 2.99 or patch diversity more than 1.02 at the riparian buffer scale could improve water quality. The above results showed that strengthening the management of land use at the sub-basin and riparian 100 m scales and setting a reasonable threshold of land use structure and spatial pattern can effectively prevent water quality from deteriorating.

[Bisulfite Promoted Minute Fe2+-Activated Peroxydisulfate for Paracetamol Degradation].

Fe2+ has been commonly selected to activate peroxydisulfate(PDS) for sulfate radical(SO4-·) generation because of its eco-friendly, cost-effective, and high activity characteristics. However, Fe2+ can be rapidly oxidized to Fe3+ in the reaction, leading to poor utilization of iron for PDS activation. Further, a fairly high concentration of Fe2+ is generally required and may cause iron sludge production and secondary pollution. In this study, a minute Fe2+-activated PDS system induced by bisulfite(BS) was used to degrade paracetamol(APAP) in water. The results showed that the Fe2+-PDS system could be enhanced by the circulation of Fe2+-Fe3+ with the injection of BS and by keeping Fe2+ at a high concentration. Under the optimal conditions(PDS=0.6 mol·L-1; BS=0.4 mol·L-1; Fe2+=10 µmol·L-1; pH=4), 100% APAP(4 µmol·L-1) was removed within 180 s. The degradation rate of APAP increased with the increase in BS(0-0.6 mmol·L-1) and PDS(0.2-1.5 mmol·L-1) concentration, and a modest Fe2+ concentration could accelerate APAP removal. Co-existing substances inhibited the APAP removal and followed the order of HCO3->HPO42->Cl->NO3->humic acid(HA). Based on the quenching experiments and electron paramagnetic resonance spectroscopy test, SO4-· was shown to be the primary reactive species for APAP decomposition in the BS-Fe2+-PDS process. Three-dimensional fluorescence spectroscopy revealed that APAP intermediates had fluorescence characteristics. Moreover, five intermediates were identified, and the probable APAP degradation pathways were proposed. The removal efficiencies of APAP were lower in real waters than that in ultrapure water. Nevertheless, the removal effect was greatly improved after a prolonged reaction time. All results indicated that the BS-Fe2+-PDS system could be a promising method for organic pollutant treatment.

[Characteristics of Microplastic-derived Dissolved Organic Matter(MPDOM) and the Complexation Between MPDOM and Sulfadiazine/Cu2].

Microplastic-derived dissolved organic matter(MPDOM) during the aging process could be complexed with organic pollutants, heavy metals, and other contaminants and thus affect their migration and transformation. In this study, two types of microplastics, polyethylene terephthalate(PET) and polystyrene(PS), were selected to investigate the spectral properties of MPDOM and their effect on the complexation between MPDOM and sulfadiazine(SDZ)/copper ion(Cu2+) using the fluorescence quenching method, various spectroscopic analysis techniques, and the Ryan-Weber quenching model. The results of UV-vis absorption spectroscopy analysis showed that the molecular weight of the two MPDOMs decreased; the aromaticity and humification increased; and the carboxyl, carbonyl, hydroxyl, and ester substituents on aromatic rings increased after aging. The fluorescence quenching process between MPDOM and SDZ/Cu2+ was static quenching. After quenching, the aromaticity and humification of the two MPDOMs were similar, and the molecular weights were comparable. Combined with three-dimensional fluorescence spectra and parallel factor analysis, two humic-like components and one protein-like component were identified. In addition, the protein-like components of MPDOM reacted preferentially with SDZ and were more sensitive to Cu2+. The results of the Ryan-Weber quenching model revealed that the binding ability of humic-like components to PET-DOM was higher in both SDZ and Cu2+ quenching systems, but the binding ability of MPDOM in the SDZ quenching system was generally stronger than that in the Cu2+ system.

[Community Composition, Symbiotic Patterns, and Influencing Factors of Planktonic Fungi in Urban Lakes of Nanchang].

To investigate the characteristics of planktonic fungal communities in Nanchang lakes and the mechanism of environmental stress on planktonic fungal communities, surface water samples were collected from seven major urban lakes evenly distributed in different county-level districts of Nanchang in the dry (February and December), normal (April and October), and wet (June and August) seasons, respectively. The environmental stressors such as WT, DO, NH4+-N, and NO3--N were measured; the characteristics of planktonic fungal communities were studied using high-throughput sequencing; the symbiotic patterns of planktonic fungal communities were elucidated using network analysis and other methods; and the environmental stressors affecting the structure and symbiotic patterns of planktonic fungal communities were revealed. The results showed that ① the planktonic fungal community composition in lakes of Nanchang varied significantly among seasons but not significantly among the lakes. WT, DO, pH, and NH4+-N were the significant environmental stressors affecting the planktonic fungal community composition. ② The dominant phyla of the planktonic fungal community were Chytridiomycota (9.55%-33.14%), Basidiomycota (0.48%-4.25%), and Ascomycota (1.29%-3.19%), and the sizes of the dominant phyla were in the following order:wet season>normal season>dry season. The relative abundance of Chytridiomycota was significantly higher in the wet season than that in the normal season and the dry season, the relative abundance of Basidiomycota was significantly lower in the dry season than that in the normal and wet seasons, and the difference in Ascomycota among seasons was not significant. ③ The stability size of the planktonic fungal community symbiosis network in lakes of Nanchang was in the following order:wet season>normal season>dry season. WT was the best environmental stressor affecting the planktonic fungal community symbiosis pattern. The study can provide theoretical basis for the comprehensive evaluation and management study of the lake and provide guidance for protecting the lake ecosystem in the middle and lower reaches of the Yangtze River.

Effects of high manganese-cultivated seedlings on cadmium uptake by various rice (Oryza sativa L.) genotypes.

Cadmium (Cd) contamination in paddy soil threatens rice growth and food safety, enriching manganese (Mn) in rice seedlings is expected to reduce Cd uptake by rice. The effects of 250 µM Mn-treated seedlings on reducing Cd uptake of four rice genotypes (WYJ21, ZJY1578, HHZ, and HLYSM) planted in 0.61 mg kg-1 Cd-contaminated soil, were studied through the hydroponic and pot experiments. The results showed that the ZJY1578 seedling had the highest Mn level (459 µg plant-1), followed by WYJ21 (309 µg plant-1), and less Mn accumulated in the other genotypes. The relative expression of OsNramp5 (natural resistance-associated macrophage protein) was reduced by 42.7 % in ZJY1578 but increased by 23.3 % in HLYSM. The expressions of OsIRT1 (iron-regulated transporter-like protein) were reduced by 24.0-56.0 % in the four genotypes, with the highest reduction in ZJY1578. Consequently, a greater reduction of Cd occurred in ZJY1578 than that in the other genotypes, i.e., the root and shoot Cd at the tillering were reduced by 27.8 % and 48.5 %, respectively. At the mature stage, total Cd amount and distribution in the shoot and brown rice were also greatly reduced in ZJY1578, but the inhibitory effects were weakened compared to the tillering stage. This study found various responses of Cd uptake and transporters to Mn-treated seedlings among rice genotypes, thus resulting in various Cd reductions. In the future, the microscopic transport processes of Cd within rice should be explored to deeply explain the genotypic variation.

More management is needed to improve the effectiveness of artificial grassland in vegetation and soil restoration on the three-river headwaters region of China.

Establishing an artificial grassland is a common measure employed to restore heavily degraded alpine grasslands for regional sustainability. The Three-River Headwaters Region in China has significant areas of black-soil-type grassland which is typified by heavy degradation; nearly 35% of the grassland regions in the Three-River Headwaters Region has degraded into this type. There are different plant community types of black-soil-type grasslands, however, it is not clear which restoration measures should be adopted for different kinds of black-soil-type grasslands. Here, we investigate the plant community characteristics and soil physicochemical properties of artificial grasslands, two types of black-soil-type grasslands, and native undegraded grassland in the Three-River Headwaters Region, then analyzed the direct and indirect interactions between the plant and soil properties by partial least squares path models (PLS-PM). Our results revealed that establishing artificial grassland significantly increased aboveground biomass and plant community coverage, and also decreased plant species richness and diversity and soil water content, soil organic carbon and total nitrogen in the 0-10 cm soil layer as compared with black-soil-type grasslands. Plant community diversity had a positive effect on plant community productivity, soil nutrient, and soil water content in native undegraded grassland. These results suggest that more management interventions are needed after establishing an artificial grassland, such as reducing dominant species in two types of black-soil-type grasslands, water regulation in the A. frigida-dominated meadow, diversifying plant species (i.e., Gramineae and sedges), and fertilizer addition.

Reduced soil multifunctionality and microbial network complexity in degraded and revegetated alpine meadows.

Understanding how microbial processes develop and change in alpine meadow soils is key to global initiatives toward environmental sustainability and local land management. Yet, how microbial interactions mediate soil multifunctionality in disturbed and managed alpine meadows remains understudied. Here, we investigated multiple community metrics, particularly microbial network properties and assembly processes, of soil bacterial and fungal communities and their links to certain soil functions along a degradation-restoration sequence of alpine meadows in the Qinghai-Tibetan Plateau. Meadow degradation caused significant declines in soil hydraulic conductivity (e.g., higher bulk density, reduced soil porosity and water content) and nitrogen availability, leading to lowered soil multifunctionality. Meadow degradation only caused weak changes in microbial abundance, alpha diversity, and community composition, but remarkably reduced bacterial network complexity, to a less extent for fungal network properties. Short-term artificial restoration with productive grass monocultures did not restore soil multifunctionality, in turn even destabilized bacterial network and favored pathogenic over mutualistic fungi. Soil fungi community are more stable than bacteria in disturbed alpine meadows, and they evolved with distinct assembly strategies (stochastic-dominant versus deterministic-driven processes, respectively). Further, microbial network complexity, positively and better predicts soil multifunctionality than alpha diversity. Our work shows how microbial interaction complexity may enhance soil multifunctionality in degraded alpine meadow ecosystems, noting that meadow restoration with low plant species diversity may failed in restoring multiple ecosystem functions. These findings would help predict the outcomes of global environmental changes and inform management strategies in regional grassland conservation and restoration.

[Bacterioplankton Communities and Assembly Mechanisms in Wet Season of Lakes, Nanchang].

Bacterioplankton communities play an important role in nutrient cycling and organic matter decomposition in urban lakes. Based on high-throughput sequencing, we analyzed the temporal (April, June, and August) and urban-suburban difference and assembly of bacterioplankton communities in lakes of Nanchang City. Our results showed that:① the dominant bacterioplankton communities in the lakes were Actinobacteria (41.60%), Proteobacteria (22.29%), Cyanobacteria (16.21%), and Bacteroidota (10.17%). ② There were significant differences in bacterial communities between April, June, and August but not between urban lakes and suburban lakes. The abundance of 10 bacteria, mainly Proteobacteria (April>June>August) and Cyanobacteria (June>August>April), was significantly different among the three months. There was a significant distance decay pattern in June, which was not seen in April and August. ③ The proportion of non-freshwater bacteria was significantly higher in June than that in April and August, but there were no significant differences between urban lakes and suburban lakes. ④ Deterministic processes dominated the assembly of bacterioplankton communities, whereas stochastic processes had a lower contribution. Water temperature (WT) was the environmental factor that best explained the changes in bacterioplankton communities in the lakes.

[Enrichments, Migrations, and Conversions of Heavy Metal in the Soil/Sediment-Plant System Towards the Lake in Typical Poyang Lake Wetland].

A large area of periodic water-level-fluctuating zone (WLFZ) in the Poyang Lake, regulated by a special hydrologic rhythm, was deposited with significant amounts of nutrients and pollutants. In this study, the WLFZ located in a typical estuarine wetland was chosen and sampling transects were arranged according to different vegetation types towards the lake. Soil/sediment and dominant plant (different tissues) samples were collected, and contents and enrichment levels of heavy metals (Cr, Ni, Cu, Zn, As, Cd, Sb, and Pb) in these samples were analyzed. The migrations and conversions of heavy metal in the soil/sediment-plant system were evaluated, and driving environmental factors were explored. The results indicated that the contents of heavy metal in the soil/sediment presented an obvious single-peak distribution towards the lake, that is, the seasonally flooded zone was identified as the main deposited zone of heavy metals. There was a high enrichment level of Cu, Pb, and Sb in the soil/sediment from the WLFZ, and significant Cu and Sb pollution was identified (EF>5). The results from the potential ecological risk evaluation (RI) indicated that the ecological risk of the seasonally flooded zone was significantly higher than that in the flooded and unflooded zones, being at a low ecological risk (70 ≤ RI<140). There was no obvious spatial distribution of heavy metal contents in the dominant plant towards the lake, whereas significant seasonal differences were detected. The levels of heavy metals in plants at the growth phase (April) were higher compared to those at the other sampling times. The tissue distributions of heavy metal content basically followed the sequence of soil/sediment>root ≥ above-ground part, except for in Cd and Sb. The Cd content in the roots was significantly higher than that in the sediment/soil, and the Sb concentration was not significantly different among the three tissues. The bio-enrichment coefficient (BAF) and transfer factor (TF) of heavy metal in the dominant plant towards the lake did not show an obvious spatial pattern, and BAF and TF of heavy metals in the Artemisia capillaris Thunb. was higher than those in other dominant plants. The RDA revealed that pH, organic matter, plant height, and Fe-Mn oxides were the key environmental factors driving the migrations of heavy metals in the soil/sediment-plant system. These results will provide scientific basis and theoretical support for the biodiversity conservation and heavy metal pollution prevention and management in wetlands of the Poyang Lake.

A meta-analysis reveals that geographical factors drive the bacterial community variation in Chinese lakes.

The biogeographical distribution of plants and animals has been extensively studied, however, the biogeographical patterns and the factors that influence bacterial communities in lakes over large scales are yet to be fully understood, even though they play critical roles in biogeochemical cycles. Here, bacterial community compositional data, geographic information, and environmental factors were integrated for 326 Chinese lakes based on previously published studies to determine the underlying factors that shape bacterial diversity among Chinese lakes. The composition of bacterial communities significantly varied among the three primary climatic regions of China (Northern China, NC; Southern China, SC; and the Tibetan Plateau, TIP), and across two different lake habitats (waters and sediments). Sediment bacterial communities exhibited significantly higher alpha-diversity and distance-decay relationships compared to water communities. The results indicate that the "scale-dependent patterns" of controlling factors, primarily influenced by geographical factors, become increasingly pronounced as the spatial scale increases. At a national scale, geographical factors exerted a dominant influence on both the water and sediment communities across all lakes, as geographical barriers restrict the dispersal of individuals. At smaller spatial scales, temperature-driven selection effects played a greater role in shaping water bacterial community variation in the NC, SC, and TIP, while geographical factors had a stronger association with sediment bacterial community variation in the lakes of the three regions. This synthesis offers novel insights into the ecological factors that determine the distribution of bacteria in Chinese lakes.

Integrating Preoperative Computed Tomography and Clinical Factors for Lymph Node Metastasis Prediction in Esophageal Squamous Cell Carcinoma by Feature-Wise Attentional Graph Neural Network.

PURPOSE: This study aimed to propose a regional lymph node (LN) metastasis prediction model for patients with esophageal squamous cell carcinoma (ESCC) that can learn and adaptively integrate preoperative computed tomography (CT) image features and nonimaging clinical parameters. METHODS AND MATERIALS: Contrast-enhanced CT scans taken 2 weeks before surgery and 20 clinical factors, including general, pathologic, hematological, and diagnostic information, were collected from 357 patients with ESCC between October 2013 and November 2018. There were 999 regional LNs (857 negative, 142 positive) with pathologically confirmed status after surgery. All LNs were randomly divided into a training set (n = 738) and a validation set (n = 261) for testing. The feature-wise attentional graph neural network (FAGNN) was composed of (1) deep image feature extraction by the encoder of 3-dimensional UNet and high-level nonimaging factor representation by the clinical parameter encoder; (2) a feature-wise attention module for feature embedding with learnable adaptive weights; and (3) a graph attention layer to integrate the embedded features for final LN level metastasis prediction. RESULTS: Among the 4 models we constructed, FAGNN using both CT and clinical parameters as input is the model with the best performance, and the area under the curve (AUC) reaches 0.872, which is better than manual CT diagnosis method, multivariable model using CT only (AUC = 0.797), multivariable model with combined CT and clinical parameters (AUC = 0.846), and our FAGNN using CT only (AUC = 0.853). CONCLUSIONS: Our adaptive integration model improved the metastatic LN prediction performance based on CT and clinical parameters. Our model has the potential to foster effective fusion of multisourced parameters and to support early prognosis and personalized surgery or radiation therapy planning in patients with ESCC.

Potential of granular complexes of lime and montmorillonite for stabilizing soil cadmium and the underlying mechanisms.

Cadmium (Cd) contaminated soils were widely remediated by alkaline materials in powder, while the effects of granular materials are still unknown. This study was conducted to prepare granular materials based on hydrated lime and montmorillonite with ratios of 1:1, 1:2, and 1:3 (LM1, LM2, and LM3); their effects and mechanisms on stabilizing Cd in hydroponic, pot, and field conditions were further explored. The results showed that powdery materials caused intense pH elevations within 30-60 min and dissolved-Cd reductions within 8-100 min. However, granular materials significantly delayed these effects; the highest solution pH and lowest dissolved-Cd occurred after 250 min. The LM1 granules induced a much higher reduction of dissolved-Cd (99.8%) than that in the LM2 (53.6%) and LM3 granules (14.3%) due to the generation of more cadmium carbonate precipitates. Additionally, the soil pH gradually decreased after an intense elevation induced by powdery materials, but the LM1 granules maintained the soil pH at approximately 7.0, resulting in a lower level of CaCl2-extractable Cd (0.03 mg kg-1) than the LM1 powder (0.22 mg kg-1) after 30 d of cultivation. Similar to lime powder, a small spatial variation (Std. of 3.45) of DGT (diffusive gradient in thin films) extractable Cd in soil profile was observed in the LM1 granules, revealing a homogeneous stabilization effect induced by the LM1 granules. Accordingly, the LM1 granules induced a higher reduction in brown rice Cd (50.9%) than that in the LM1 powders (35.1%). Thus, the granular material of hydrated lime and montmorillonite (1:1) h the potential to replace lime powder in the remediation of Cd-contaminated field.

Characterization of copper binding to biochar-derived dissolved organic matter: Effects of pyrolysis temperature and natural wetland plants.

Characterization of the biochar-derived dissolved organic matter (BDOM) is essential to understanding the environmental efficacy of biochar and the behavior of heavy metals. In this study, the binding properties of BDOM derived from different pyrolysis temperatures, wetland plants, and plant organs with Cu was investigated based on a multi-analytical approach. In general, the pyrolysis temperature exhibited a more significant impact on both the spectral characteristics of BDOM and Cu binding behavior than those of the feedstocks. With the pyrolysis temperature increased, the dissolved organic carbon, aromaticity, and fluorescence substance of BDOM decreased and the structure became more condensed. Humic-and tryptophan-like substance was more susceptible to the addition of Cu for BDOM pyrolyzed at 300 â„ƒ and 500 â„ƒ, respectively. In addition, the more tyrosine-like substance is involved in Cu binding at higher pyrolysis temperature (500 â„ƒ). However, the fluvic-like substance occurred preferentially with Cu than the other fluorophores. Moreover, the higher binding capacity for Cu was exhibited by the humic-like substance and by BDOM derived from the higher pyrolysis temperature and the lower elevation plants with the corresponding average stability constants (log KM) of 5.58, 5.36, and 5.16.

Spectral characteristic of the waters with different sizes of particles: impact of water quality and land-use type.

Natural colloids (NCs) are heterogeneous mixtures of particles in the aquatic environments that are strongly influenced by land use and water quality between terrestrial and aquatic environments. However, the relevant study paid little attention to the difference among the waters with different sizes of particles (e.g., suspended particulate matter (SPM), NCs, and the truly soluble substances). In this study, the spectral properties of these different waters were investigated from different land-use types in the Yuan River basin, China. Results of the UV-visible absorption spectral showed that with the particle size increased, the aromaticity, chromophoric dissolved organic matter, and humification degree of organic matter increased, while the condensation degree decreased. Data analysis from the fluorescence indices indicated that the source and the autochthonous feature of the truly soluble substances differed from that of NCs and SPM, whereas the protein-like component was mainly combined with the relatively larger size of particles (i.e., SPM and NCs), especially the downstream. Although the spectral characteristics of the water samples were strongly influenced by the water quality (> 45%), the land-use type might be the real potential impactor. Furthermore, the influence of land-use type on the spectral properties differed between the large and small scale of the buffer strips and between the mainstream and the tributaries. And this effect was more significant on the fluorescence properties in the mainstream and the spectral properties for NCs than for SPM. The study helps to understand the biogeochemical effects of the waters with different particle sizes.

[Effect of Colloids in Sediment and Soil on Their Sorption Behavior of Chloramphenicol].

Natural colloids (NCs) are ubiquitous in sediments and soils, which could affect the environmental fate of antibiotics. Focusing on chloramphenicol (CAP), different sources of the sediments and soil samples were selected to research the sorption capacity of NCs with different relative molecular weights towards CAP, as well as the impactors, combined with a multi-method approach including cross-flow ultrafiltration, dynamic light scattering, UV-visible absorption spectroscopy, and three-dimensional excitation-emission matrix fluorescence spectroscopy. The results revealed that the low molecular weight (LMW) of NCs was associated with a low autochthonous origin and a higher humification degree. The high molecular weight (HMW) of NCs were mainly terrestrial sources, and the aromatic rings contained more oxygen-containing functional groups such as carboxyl, hydroxyl, and carbonyl groups. Four fluorescence components were identified using the parallel factor analysis model, and the humic-like substances were the primary fluorescent components. Moreover, based on batch experiments, the study investigated the sorption behavior of CAP by the different fractions of the solid samples. The results showed that the sorption processes of CAP were well fitted by the linear model and Freundlich model. The average sorption rate of CAP by the original solid samples and the solid samples with removed organic and inorganic carbon were 4.46%, 3.93%, and 6.61%, respectively, indicating that organic carbon played an important role in the sorption behavior of CAP. The results of the sorption experiments indicated that CAP was more easily adsorbed on the LMW NCs that had a high degree of humification and a more aliphatic chain on the aromatic rings. In addition, tryptophan-like protein substances in NCs showed the inhibiting effect on the sorption progress of CAP. Redundancy analysis indicated that the sorption of CAP by NCs in sediment and soil was mainly related to the source, aromatics, oxygen functional groups on aromatic rings, humification degree, and humic-like substances of NCs.