Pathways of inhibition of filamentous sludge bulking by slowly biodegradable organic compounds.

The organic compound composition of wastewater, serves as a crucial indicator for the operational performance of activated sludge processes and has a major influence on the development of filamentous bulking in activated sludge. This study focused on the impact of typical soluble and slowly-biodegradable organic compounds, investigating the pathways through which these substrates affect the occurrence of filamentous bulking in systems operated under both high- and low-oxygen conditions. Results showed that slowly-biodegradable organic compounds lead to a concentrated distribution of microorganisms within flocs, with inward growth of filamentous bacteria. Both Tween-80 and granular starch treated systems exhibited a significant increase in protein content. The glucose system, utilizing soluble substrates, exhibited a markedly higher total polysaccharide content. Microbial communities in the Tween-80 and granular starch treated systems were characterized by a higher abundance of bacteria known to enhance sludge flocculation and settling, such as Competibacter, Xanthomonadaceae and Zoogloea. These findings are of high significance for controlling the operational performance and stability of activated sludge systems, deepening our understanding and providing a novel perspective for the improvement of wastewater treatment processes.

A comparative study on the formation of nitrogen-containing organic compounds in cloud droplets and aerosol particles.

Nitrogen-containing organic compounds (NOCs) may potentially contribute to aqueous secondary organic aerosols, yet the different formation of NOCs in aerosol particles and cloud droplets remains unclear. With the in-situ measurements performed at a mountain site (1690 m a.s.l.) in southern China, we investigated the formation of NOCs in the cloud droplets and the cloud-free particles, based on their mixing state information of NOCs-containing particles by single particle mass spectrometry. The relative abundance of NOCs in the cloud-free particles was significantly higher than those in cloud residual (cloud RES) particles. NOCs were highly correlated with carbonyl compounds (including glyoxalate and methylglyoxal) in the cloud-free particles, however, limited correlation was observed for cloud RES particles. Analysis of their mixing state and temporal variations highlights that NOCs was mainly formed from the carbonyl compounds and ammonium in the cloud-free particles, rather than in the cloud RES particles. The results support that the formation of NOCs from carbonyl compounds is facilitated in concentrated solutions in wet aerosols, rather than cloud droplets. In addition, we have identified the transport of biomass burning particles that facilitate the formation of NOCs, and that the observed NOCs is most likely contributed to the light absorption. These findings have implications for the evaluation of NOCs formation and their contribution to light absorption.

Photochemical activity of water-soluble organic compounds in motor vehicle exhaust particulate matter.

Particulate matter from motor vehicle exhaust is a type of important atmospheric particulates, which can absorb sunlight affecting its photochemical behavior. However, the photochemical activity of water-soluble organic compounds (WSOC) in motor vehicle exhaust particulate matter has not been explored. Here, we applied WSOC in particulate matter from motor vehicle exhaust to investigate the photogenerating ability of its reactive oxygen species (ROS) and its effect based on model phenol photodegradation with the comparison between WSOC in diesel particulate matter and in gasoline particulate matter. The WSOC in diesel particulate matter indicates higher abililty to generate ROS. The main active substance produced by WSOC in the presence of light is 3WSOC*, the secondary substance is 1O2, and small amounts of ·OH and O2·- are also produced. Less active material was produced as WSOC photoaging time increases. Furthermore, the WSOC in diesel particulate matter is more sensitive to light exposure compared to WSOC in gasoline particulate matter. The effects of common atmospheric ionic components on model phenol photodegradation were also explored. Whether WSOC of diesel particulate matter or WSOC of gasoline particulate matter, ammonium nitrate, ammonium sulfate, and ferric chloride promote degradation of model phenol, and copper sulfate inhibited model phenol degradation. However, a different trend emerged with the addition of sodium chloride, which promoted the degradation of model phenol in WSOC of diesel particulate matter and inhibited the degradation in WSOC of gasoline particulate matter.

Binding characters of biomass burning smoke-derived dissolved organic matter with Cu(II) in aqueous environment: Roles of functional groups and organic components.

The environmental effect of biomass burning smoke-derived dissolved organic matter (BBS-DOM) has attracted growing attention due to the increasing wildfire globally. BBS-DOM eventually deposits on the water and soil environments, thus altering the environmental behaviors of pollutants (e.g., heavy metals) in the surface environments of the wildfire region. However, presently, the binding characters between heavy metals and BBS-DOM remains unknown. In this study, alfalfa, pinewood, and corn straw were burned at 300 °C and 600 °C to produce BBS-DOMs and their binding characters with Cu(II) were investigated using fluorescence excitation-emission matrix spectra coupled with parallel factor (EEM-PARAFAC), synchronous fluorescence spectra combined with two-dimensional correlation spectroscopy (2D-SFS-COS) and FTIR combined with two-dimensional correlation spectroscopy (2D-FTIR-COS). The fluorescence quenching/enhancing results after Cu(II) addition suggested that the binding capacities with Cu(II) of various organic components in BBS-DOMs followed an order of polyphenols-like matters (Ex/Em: 220 nm/310 nm) > aromatic protein-like matters (Ex/Em: 275 nm/310 nm) ≈ small humic-like matters (Ex/Em: 300 nm/380 nm) > large humic-like matters (Ex/Em: 330 nm/410 nm). Interestingly, the quenching effect of Cu(II) addition on the fluorescence intensities of polyphenols-like matters and humic-like matters decreased with their increasing abundances, which possibly depended on the proportion of organic ligands of these components. Furthermore, 2D-FTIR-COS demonstrated that the binding sequence of different functional groups followed deprotonated -COOH→deprotonated phenol-OH→-C]O of aldehydes, ketones, and lactones/aromatic rings/-NH→C-O-C/C-OH of ethers and alcohols. Another novelty was that Cu(II) binding could increase the molecular size and humification of BBS-DOMs, due to the bridge effect of Cu(II). This work provides an importantly theoretical basis for deeply understanding the mechanism of BBS-DOM binding with Cu(II) at the molecular level, which is a key for reasonably predicting the multimedia-crossing effects of BBS-DOM and the environmental behavior of heavy metals in the wildfire region.

Machine learning-based q-RASAR predictions of the bioconcentration factor of organic molecules estimated following the organisation for economic co-operation and development guideline 305.

In this study, we utilized an innovative quantitative read-across (RA) structure-activity relationship (q-RASAR) approach to predict the bioconcentration factor (BCF) values of a diverse range of organic compounds, based on a dataset of 575 compounds tested using Organisation for Economic Co-operation and Development Test Guideline 305 for bioaccumulation in fish. Initially, we constructed the q-RASAR model using the partial least squares regression method, yielding promising statistical results for the training set (R2 =0.71, Q2LOO=0.68, mean absolute error [MAE]training=0.54). The model was further validated using the test set (Q2F1=0.77, Q2F2=0.75, MAEtest=0.51). Subsequently, we explored the q-RASAR method using other regression-based supervised machine-learning algorithms, demonstrating favourable results for the training and test sets. All models exhibited R2 and Q2F1 values exceeding 0.7, Q2LOO values greater than 0.6, and low MAE values, indicating high model quality and predictive capability for new, unidentified chemical substances. These findings represent the significance of the RASAR method in enhancing predictivity for new unknown chemicals due to the incorporation of similarity functions in the RASAR descriptors, independent of a specific algorithm.

Molecular insight into biomass-burning smoke water-soluble organic matter binding with Cd(II): Comprehensive analysis from fluorescence EEM-PARAFAC, FT-ICR-MS and two-dimensional correlation spectroscopy.

The deposition of biomass-burning smoke water-soluble organic matter (BBS-WSOM) significantly affects the environmental behavior of heavy metals in aqueous environments. However, the interactions between BBS-WSOM and heavy metals at the molecular level remain unknown. This study combined FT-ICR-MS, fluorescence spectrum, FTIR, and two-dimensional correlation spectroscopy to anatomize the molecular characteristics of BBS-WSOM binding with Cd(II). The results show that CHO and CHOP compounds were responsible for the fluorescence response of BBS-WSOM at Ex: 225 nm and 275 nm/Em: 325 nm, and abundant proteins or CHON compounds were responsible for the fluorescence response of BBS-WSOM at Ex: 225-250 nm/Em: 350-450 nm and Ex: 300-350 nm/Em: 350-450 nm, which was very different from the fluorescence molecules in natural organic matters. Fluorescence change after Cd(II) addition indicated that CHOP and CHOS compounds enhanced BBS-WSOM binding with Cd(II). Differently, the CHON compounds could weaken the binding of other compounds with Cd(II). Different compounds binding with Cd(II) generally followed the order: CHON/CHOS compounds>CHOP compounds>CHO compounds, and the chemical groups binding with Cd(II) generally followed the prioritization: -COO-> -NH/SO>P = O/P-O>aromatic ring>CO>C-OH of phenol/alcohol>C-O-C. This study provides a profound insight into the interaction between BBS-WSOM and Cd(II) at the molecular level.

Insight into response mechanism of short-chain fatty acids to refined microbial transformation order of dissolved organic matter ranked by molecular weight during dry anaerobic digestion.

Dynamic transformation of dissolved organic matter (DOM) contributes to short-chain fatty acids (SCFAs) production during anaerobic digestion. However, the impact of refined transformation of DOM ranked by molecular weight (MW) on SCFAs has never been investigated. Results indicated that DOM conversion order was 3500-7000 Da>(MW>14000 Da) > 7000-4000 Da during hydrolysis stage, while it was independent of their MW in acidogenesis phase and followed a low to high MW order during methanogenesis stage. Proteins-like DOMs with different MW were closely related to SCFAs. Eight groups of microorganisms (e.g., Bacillus and Caldicoprobacter) responsible for the conversion of proteins-like DOMs to SCFAs. The possible routes linking environmental properties to microorganisms-proteins-like DOMs-SCFAs connections were constructed. Microbial activity modifications by regulating moisture, pH, NO3--N and NH4+-N can expedite the conversion of proteins-like DOMs to SCFAs. The study emphasizes the importance of MW-classification-based biotransformation of organic waste, offering a potential strategy to enhance anaerobic digestion performance.

Long-term acclimation to organic carbon enhances the production of loliolide from Scenedesmus deserticola.

Production of functional biocompounds from microalgae has garnered interest from different industrial sectors; however, their overall productivity must be substantially improved for commercialization. Herein, long-term acclimation of Scenedesmus deserticola was conducted using glucose as an organic carbon source to enhance its heterotrophic capabilities and the production potential of loliolide. A year-long acclimation on agar plates led to the selection of S. deserticola HS4, which exhibited at least 2-fold increase in loliolide production potential; S. deserticola HS4 was subjected to further screening of its cultivation conditions and fed-batch cultivation was subsequently performed in liter-scale reactors. While S. deserticola HS4 exhibited shifts in cellular morphology and biochemical composition, the results suggested a substantial increase in its loliolide productivity regardless of trophic modes. Collectively, these results highlight the potential of long-term acclimation as an effective strategy for improving microalgal crops to align with industrial production practices.

Oxyanion-Sensitive Catalytic Activity of Ni(II)/Oxyanion Systems for Heterogeneous Organic Degradation: Differential Oxidizing Capacity of Ni(III) and Ni(IV) as High-Valent Intermediates.

This study demonstrated that NiO and Ni(OH)2 as Ni(II) catalysts exhibited significant activity for organic oxidation in the presence of various oxyanions, such as hypochlorous acid (HOCl), peroxymonosulfate (PMS), and peroxydisulfate (PDS), which markedly contrasted with Co-based counterparts exclusively activating PMS to yield sulfate radicals. The oxidizing capacity of the Ni catalyst/oxyanion varied depending on the oxyanion type. Ni catalyst/PMS (or HOCl) degraded a broad spectrum of organics, whereas PDS enabled selective phenol oxidation. This stemmed from the differential reactivity of two high-valent Ni intermediates, Ni(III) and Ni(IV). A high similarity with Ni(III)OOH in a substrate-specific reactivity indicated the role of Ni(III) as the primary oxidant of Ni-activated PDS. With the minor progress of redox reactions with radical probes and multiple spectroscopic evidence on moderate Ni(III) accumulation, the significant elimination of non-phenolic contaminants by NiOOH/PMS (or HOCl) suggested the involvement of Ni(IV) in the substrate-insensitive treatment capability of Ni catalyst/PMS (or HOCl). Since the electron-transfer oxidation of organics by high-valent Ni species involved Ni(II) regeneration, the loss of the treatment efficiency of Ni/oxyanion was marginal over multiple catalytic cycles.

Sewage and Organic Pollution Compounds in Nairobi River Urban Sediments Characterized by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS).

Nairobi River sediments from locations adjacent to the Kawangware and Kiambio slums were analyzed via Fourier transform ion cyclotron resonance mass spectrometry with atmospheric pressure photoionization (APPI-FT-ICR-MS). The data from these ultrahigh resolution, untargeted measurements provided new insights into the impacts of local anthropogenic activity, which included likely benzo- and dibenzothiophene pollution with a suspected petrogenic origin, and prominent surfactant-like compositions. Other features in the data included highly abundant tetra-oxygenated compounds, and oxygenated nitrogen compounds with sphingolipid interpretations. Most notably, several hydrocarbon and oxygenated compound classes in the sediment data featured intensity patterns consistent with steroid molecular formulas, including those associated with sewage contamination investigatory work. In support of this interpretation, standards of cholesterol, ß-sitosterol, stigmasterol, coprostanol, cholestanol, and 5α-sitostanol were analyzed via APPI, to explore steroid ionization behavior. Generally, these analytes produced radical molecular ions ([M]•+), and water-loss pseudo molecular ion species ([M-H2O]•+ and [M+H-H2O]+), among various other less intense contributions. The absence of pseudo molecular protonated species ([M+H]+) was notable for these compounds, because these are often assumed to form with APPI. The standard measurements demonstrated how steroids can create the observed intensity patterns in FT-ICR-MS data, and hence these patterns have the potential to indicate sewage contamination in the analysis of other complex environmental samples. The steroid interpretation for the Kawangware and Kiambio data was further verified by subjecting the steroid standard radical molecular ions to collision-induced dissociation and comparing the detected fragments to those for the corresponding isolated ions from a Kawangware sediment sample.

Susceptible Detection of Organic Molecules Based on C3B/Graphene and C3N/Graphene van der Waals Heterojunction Gas Sensors.

Constructing van der Waals (vdW) heterostructures is a prospective approach that is essential for developing a new generation of functional two-dimensional (2D) materials and designing new conceptual nanodevices. Using density-functional theory combined with a nonequilibrium Green's function approach allows for the theoretical and systematic exploration of the electronic structure, transport properties, and sensitivity of organic small molecules adsorbed on 2D C3B/graphene (Gra) and C3N/Gra vdW heterojunctions. Calculations show the metallic properties of C3B/Gra and C3N/Gra after the formation of heterojunctions. Interestingly, the heterojunctions C3B/Gra (C3N/Gra) for the adsorption of small organic molecules (C2H2, C2H4, CH3OH, CH4, and HCHO) at the C3B (C3N) side are sensitive to the chemisorption of C2H2 and C2H4. Similarly, the Gra/C3B is chemisorbed for both C2H2 and C2H4 when adsorbed on Gra side, while it is only chemisorbed for C2H2 in Gra/C3N. Interestingly, all heterojunctions on different sides are physisorbed for CH3OH, CH4, and HCHO. Furthermore, the calculated I-V curves demonstrate that the devices based on the adsorption of C2H2 and C2H4 at each side of the heterojunction have remarkable anisotropy, in with the current being considerably greater in the zigzag direction than in the armchair direction. More specifically, with C2H2 adsorbed on the Gra side, the sensitivity along the armchair direction is up to 85.0% for Gra/C3B and close to 100% for Gra/C3N. This study reveals that C3B/Gra (C3N/Gra) heterojunctions with high selectivity, high anisotropy, and excellent sensitivity are highly prospective 2D materials for applications, which further contributes new insights into the development of future electronic nanodevices.

Novel microglial transcriptional signatures promote social and cognitive deficits following repeated social defeat.

Chronic stress is associated with anxiety and cognitive impairment. Repeated social defeat (RSD) in mice induces anxiety-like behavior driven by microglia and the recruitment of inflammatory monocytes to the brain. Nonetheless, it is unclear how microglia communicate with other cells to modulate the physiological and behavioral responses to stress. Using single-cell (sc)RNAseq, we identify novel, to the best of our knowledge, stress-associated microglia in the hippocampus defined by RNA profiles of cytokine/chemokine signaling, cellular stress, and phagocytosis. Microglia depletion with a CSF1R antagonist (PLX5622) attenuates the stress-associated profile of leukocytes, endothelia, and astrocytes. Furthermore, RSD-induced social withdrawal and cognitive impairment are microglia-dependent, but social avoidance is microglia-independent. Furthermore, single-nuclei (sn)RNAseq shows robust responses to RSD in hippocampal neurons that are both microglia-dependent and independent. Notably, stress-induced CREB, oxytocin, and glutamatergic signaling in neurons are microglia-dependent. Collectively, these stress-associated microglia influence transcriptional profiles in the hippocampus related to social and cognitive deficits.

[Construction effect of fertile cultivated layer in albic soil â Effects of inversion tillage with organic mate-rials on the redistribution of organic matter in surface layer of albic soil]. / 白浆土肥沃耕层构建效应â .不同有机物料深混对白浆土有机质在表层土壤中再分布的影响.

Soil organic matter serves as a crucial indicator for soil quality. Albic soil, characterized by a barrier layer, exhibits limitations in organic matter content, which can adversely affect crop growth and development. To elucidate the impact of deep mixing of various organic materials on the redistribution of organic matter in the surface soil of albic soil could provide theoretical and technical insights for establishing suitable plough layers for albic soil in Northeast China. We conducted a two-year positioning experiment in Shuangyashan, Heilongjiang Province with five treatments, conventional shallow tillage (0-15 cm, CK), inversion tillage (0-35 cm) without or with straw return (T35 and T35+S), inversion tillage with cattle manure (T35+M) and cattle manure plus maize straw (T35+S+M). The results showed that soil fertilization via deep mixing of organic materials to a depth of 35 cm significantly increased maize yield in albic soil, with the T35+S+M treatment demonstrating the most pronounced effect, yielding an average production of 2934.76 kg·hm-2. Compared to CK, the T35 treatment resulted in a significant 8.4% decrease in organic matter content in the tillage layer, a significant 7.6% increase in organic matter in the sub-tillage layer, and a relative richness degree of soil organic matter in the sub-tillage layer increased by 17.5%. Deep mixed return of organic materials following deep ploughing markedly increased organic matter content of the plough layer, with organic matter conversion ranging from 16.3% to 31.0%. In comparison to the T35 treatment, there was no significant increase in soil organic matter content in the T35+S tillage layer and sub-tillage layer. Conversely, soil organic matter content increased by 4.6% and 6.9% in the T35+M and T35+S+M treatments, with corresponding increase of 11.2% and 15.4% in sub-tillage layer, respectively. Additionally, the soil organic matter richness index in sub-tillage layer increased by 2.5% and 5.1%, respectively. There was a significant positive correlation between organic matter content in the entire plough layer and maize yield, with a contribution rate of 17.5%. Therefore, the utilization of organic fertilizer or a combination of organic fertilizer and straw deep mixing can quickly fertilize albic soil by increasing soil organic matter content in both the whole tillage layer (0-35 cm) and the sub-tillage layer (15-35 cm).

Soil organic carbon fractions and their stability under different land uses in wind erosion area of Northeast China.

Exploring the physical fractions of organic carbon and influencing mechanisms in grassland, forest, and farmland soils in wind erosion area can provide scientific basis for carbon sequestration, land utilization, wind prevention measure making, and fertility restoration of sloping farmland in the region. We examined the differentiation of aggregate organic carbon and density fractionation organic carbon in 0-15 cm soil layer across grassland, forest, and sloping farmland with 350 m long and 5° slope gradient in the wind erosion area of Meilisi District, Qiqihar, Heilongjiang, as well as the sloping farmland in the downhill section, middle section, and uphill section with every 100 m apart from the bottom to the top. The results showed that soil aggregates >2 mm were all destroyed across grassland, forest, and farmland soils, while the percentage of aggregates <0.053 mm was significantly higher than that of other sizes. The percentage of various soil aggregates, organic carbon content from density fractionations, and the proportion of organic carbon in the heavy fraction aggregates in farmland were significantly lower than that in grassland and forest soils. Soil aggregates in the uphill section of farmland were completely destroyed, and organic carbon content in various size aggregates and density fractionations gradually decreased with increasing slope. The proportion of organic carbon in the heavy fraction aggregates decreased, but that in light fraction aggregates increased gradually. Soil organic carbon and available potassium were key factors affecting aggregate stability, aggregate organic carbon content, and organic carbon content in density fractionations, while the loss of organic carbon in aggregate led to a decrease in aggregate stability. In summary, compared with grassland and forest soils, the stability of soil aggregates, the aggregate organic carbon content, the organic carbon content in density fractionations, and the proportion of organic carbon in heavy fraction aggregates in farmland all decreased in the wind erosion area of Northeast China. With the increases of slope, the aggregate organic carbon content, the organic carbon content in density fractionations, and the proportion of organic carbon in the heavy fraction aggregates in sloping farmland all decreased. Planting trees, conserving and expanding grassland area, and increasing the application of organic materials in sloping farmland in wind erosion area are effective approaches to stabilize and increase carbon storage, improve soil structure, and enhance soil quality.

Tracing fluorescent dissolved organic matter (fDOM) characteristics and water quality parameters: Insights from an urban industrial river to marine zone.

This study aims to identify continuous water quality changes and identify fluorescence properties from urban rivers to marine zones. Various types of natural and anthropogenic sources derived dissolved organic matter (DOM) have been identified in this study. These include soil-derived DOM, plant remnants, and soluble particles produced when organic material partially decomposes and is released by microorganisms, such as bacteria, algae, and plants. DOM was characterized using a three-dimensional excitation-emission matrix (3DEEM), parallel factor analysis (PARAFAC), and water quality parameters from the Buriganga River, Dhaka to Patenga Seaport, Chittagong, along with the Shitalakshya River, a small portion of the Padma River, and the Meghna River. To better understand the data analysis, the study area was divided into three central regions: urban industrial rivers, industrial estuarine rivers, and marine zones. In the urban industrial river, 3DEEM and PARAFAC identified five fluorophores (peaks: A, C, M, T, and Tuv) with five components: detergent-like, fulvic-like, tryptophan or protein-like, fulvic-like (C-type), and protein-like, which might originate from the industrial activities and sewage pollution. In the industrial estuarine river zone, three fluorophores have been identified (peaks: A, C, Tuv) with two known components, namely, fulvic acid (A-type) and fulvic acid (C-type), with an unknown photoproduct at Ex/Em = 295/368 (peak Tuv). Components in the industrial river zone may originate from terrestrial sources, indicating vegetation along the river. In the marine zone, four fluorophores have been identified (peaks: Tuv, A, T, C) with two components, that is, protein- or tryptophan-like and humic acid-like from coral origin. The intensities of both fulvic-like and protein-like substances were high in urban industrial river water owing to industrial activity and sewage pollution. SUVA254 suggests high aromaticity in all three regions, whereas the optical properties suggest that terrestrial and microbial components are present in the urban industrial and estuarine rivers. This further indicates that urban industrial river water quality is highly polluted. The lowest degradation potential index (DPI) in the marine zone might result from the presence of the highest number of dissolved solids in the water, and the highest DPI of industrial estuarine rivers explains the comparatively high presence of terrestrial-derived humic (A)- and humic (C)-like components in the ratio to the unknown photoproduct of mid-wavelength. PRACTITIONER POINTS: This study's uniqueness is a 220-km cruise from an urban river to a coastal seaport to analyze fluorescence properties. The study found that most water parameters were within the DoE standards, except for DO, which was consistently low. 3DEEM-PARAFAC identified five fluorophores linked to detergent, fulvic, and protein-like substances from sewage and industrial sources. Our study concludes that microbial and terrestrial sources dominate dissolved organic matter in urban, estuarine, and marine regions.

Label-free ratiometric fluorescence detection of Pb2+via structure-specific fluorescent dyes and dual signal amplification.

Lead ions (Pb2+) are a widely distributed and highly toxic heavy metal pollutant, which seriously threatens the environment, economy and human safety. Here, a label-free ratiometric fluorescent biosensor was constructed for Pb2+ detection using DNAzyme-driven target cycling and exonuclease III (Exo III)-mediated DNA cycling as a dual signal amplification strategy. The SYBR Green I (SGI) and N-methyl mesoporphyrin IX (NMM) used in this study are characterized by low cost, storage resistance, and short preparation time compared with conventional signaling probes labeled with fluorescent groups. Unlike the single-emission fluorescence strategy, monitoring the fluorescence intensity ratio of SGI and NMM can effectively reduce external interference to achieve accurate detection of Pb2+. DNAzyme structures on the surface of magnetic beads (MBs) can recognize Pb2+ and activate the target circulatory system to cleave single-stranded DNA (ssDNA). The ssDNA further initiated the Exo III-assisted DNA circulatory system to digest double-stranded DNA (dsDNA) and release guanine-rich G1. Finally, the fluorescence signals of SGI and NMM were weakened and enhanced, respectively. The sensing strategy achieved a wide linear range from 0.5 to 500 nM and a low limit of detection (LOD) of 26.4 pM. Furthermore, its anti-interference ability and potential applicability for Pb2+ detection in actual samples were verified. This work ingeniously combines the dual signal amplification strategy with the ratiometric sensing strategy constructed by structure-specific fluorescent dyes, which provides a promising method for constructing sensitive and accurate fluorescent biosensors.

Thermodynamics and explainable machine learning assist in interpreting biodegradability of dissolved organic matter in sludge anaerobic digestion with thermal hydrolysis.

Dissolved organic matter (DOM) is essential in biological treatment, yet its specific roles remain incompletely understood. This study introduces a machine learning (ML) framework to interpret DOM biodegradability in the anaerobic digestion (AD) of sludge, incorporating a thermodynamic indicator (λ). Ensemble models such as Xgboost and LightGBM achieved high accuracy (training: 0.90-0.98; testing: 0.75-0.85). The explainability of the ML models revealed that the features λ, measured m/z, nitrogen to carbon ratio (N/C), hydrogen to carbon ratio (H/C), and nominal oxidation state of carbon (NOSC) were significant formula features determining biodegradability. Shapley values further indicated that the biodegradable DOM were mostly formulas with λ lower than 0.03, measured m/z value higher than 600 Da, and N/C ratios higher than 0.2. This study suggests that a strategy based on ML and its explainability, considering formula features, particularly thermodynamic indicators, provides a novel approach for understanding and estimating the biodegradation of DOM.

Preparation of soybean protein isolate-ester emulsifier oleogels and comparative study of their structure and properties.

In recent years, oleogel as a viscoelastic semi-solid to replace trans fatty acids and reduce saturated fatty acids in food has received more and more attention. Herein, an emulsion template method was used to produce soybean oil-based oleogels with seven different ester emulsifiers and soy protein isolate as oleogelators. The chemical and physical characteristics of oleogels produced via various crosslinking factors were comparatively examined. Results revealed that all oleogels generated ß-type needle crystals and exhibited high oil-holding capacity (>80 %), among which glycerol monolaurate G2 and diacetyl tartaric acid ester of mono-diglycerides G6 exhibited the strongest oil-holding capacity (96.6 % and 96.2 %, respectively). Furthermore, all oleogels exhibited strong thixotropic recovery, high thermal stability, as well as high gel strength (G' > G''). Of these, G2 and G6 exhibited the highest thixotropic recovery rates at 74.54 % and 78.19 %, respectively. Additionally, in accelerated oxidation trials, the peroxide value and thiobarbituric acid reactive substances of all oleogels had low oxidation rates, indicating high oxidative stability. These results contribute to a better understanding of oleogels for formulating trans-free and low-saturated foodstuffs with desired physical and functional properties.

The lipid-amylose complexes enhance resistant starch content in candelilla wax-based oleogels cookies.

The substitution of margarine with candelilla wax (CW)-based oleogel is currently a prominent focus of research in the bakery industry. However, the use of CW-based oleogel in cookies increased starch digestibility, potentially posing a risk to human health. Thus, the anti-enzymatic mechanism of lipid-amylose complexes was used to evaluate the influence of olive diacylglycerol stearin (ODS) on starch digestibility in CW-based oleogel cookies. The in vitro digestibility analysis demonstrated that the DCW/ODS-35 cookie exhibited a increase of 27.72 % in slowly digestible starch (SDS) and resistant starch (RS) contents, compared to cookie formulated with margarine. The in-vivo glycemic index analysis revealed that the DCW/ODS-35 cookie had a medium glycemic index of 68. XRD pattern suggested that the presence of ODS in oleogels facilitated the formation of lipid-amylose complexes. The DSC analysis revealed that the addition of ODS resulted in the gelatinization enthalpy of DCW-based cookies increased from 389.9 to 3314.9 J/g. The FTIR spectra indicated that the combination of ODS could promote a short-range ordered structure in DCW-based cookies. Overall, these findings demonstrated that the utilization of DCW-based oleogel presented a viable alternative to commercial margarine in the development of CW-based cookies with reduced starch digestibility.

Microglia are not necessary for maintenance of blood-brain barrier properties in health, but PLX5622 alters brain endothelial cholesterol metabolism.

Microglia, the resident immune cells of the central nervous system, are intimately involved in the brain's most basic processes, from pruning neural synapses during development to preventing excessive neuronal activity throughout life. Studies have reported both helpful and harmful roles for microglia at the blood-brain barrier (BBB) in the context of disease. However, less is known about microglia-endothelial cell interactions in the healthy brain. To investigate the role of microglia at a healthy BBB, we used the colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX5622 to deplete microglia and analyzed the BBB ultrastructure, permeability, and transcriptome. Interestingly, we found that, despite their direct contact with endothelial cells, microglia are not necessary for the maintenance of BBB structure, function, or gene expression in the healthy brain. However, we found that PLX5622 treatment alters brain endothelial cholesterol metabolism. This effect was independent from microglial depletion, suggesting that PLX5622 has off-target effects on brain vasculature.